Leukemia, Myelodysplasia, Transplantation

Image showing mitosis, with

the endoplasmic reticulum

in green, mitochondria in red,

and chromosomes in blue

Credit: Wellcome Images

Researchers say they’ve uncovered the structure of one of the most important protein complexes involved in cell division, and their finding has implications for cancer treatment.

The team mapped the anaphase-promoting complex (APC/C), which performs a wide range of tasks associated with mitosis.

The researchers believe that seeing APC/C in unprecedented detail could transform our understanding of how cells divide and reveal binding sites for future cancer drugs.

“It’s very rewarding to finally tie down the detailed structure of this important protein, which is both one of the most important and most complicated found in all of nature,” said David Barford, DPhil, of the Medical Research Council Laboratory of Molecular Biology in Cambridge, UK.

“We hope our discovery will open up whole new avenues of research that increase our understanding of the process of mitosis and ultimately lead to the discovery of new cancer drugs.”

Dr Barford and his colleagues detailed their discovery in Nature.

The researchers reconstituted human APC/C and used a combination of electron microscopy and imaging software to visualize it at a resolution of less than a billionth of a meter.

The resolution was so fine that it allowed the team to see the secondary structure—the set of basic building blocks that combine to form every protein. Alpha-helix rods and folded beta-sheet constructions were clearly visible within the 20 subunits of the APC/C, defining the overall architecture of the complex.

Previous studies led by the same team had shown a globular structure for APC/C in much lower resolution, but the secondary structure had not been mapped.

Each of the APC/C’s subunits bond and mesh with other units at different points in the cell cycle, allowing it to control a range of mitotic processes, including the initiation of DNA replication, the segregation of chromosomes along spindles, and cytokinesis. Disrupting each of these processes could selectively kill cancer cells or prevent them from dividing.

“The fantastic insights into molecular structure provided by this study are a vivid illustration of the critical role played by fundamental cell biology in cancer research,” said Paul Workman, PhD, of The Institute of Cancer Research, London.

“The new study is a major step forward in our understanding of cell division. When this process goes awry, it is a critical difference that separates cancer cells from their healthy counterparts. Understanding exactly how cancer cells divide inappropriately is crucial to the discovery of innovative cancer treatments to improve outcomes for cancer patients.”

Image showing mitosis, with

the endoplasmic reticulum

in green, mitochondria in red,

and chromosomes in blue

Credit: Wellcome Images

Researchers say they’ve uncovered the structure of one of the most important protein complexes involved in cell division, and their finding has implications for cancer treatment.

The team mapped the anaphase-promoting complex (APC/C), which performs a wide range of tasks associated with mitosis.

The researchers believe that seeing APC/C in unprecedented detail could transform our understanding of how cells divide and reveal binding sites for future cancer drugs.

“It’s very rewarding to finally tie down the detailed structure of this important protein, which is both one of the most important and most complicated found in all of nature,” said David Barford, DPhil, of the Medical Research Council Laboratory of Molecular Biology in Cambridge, UK.

“We hope our discovery will open up whole new avenues of research that increase our understanding of the process of mitosis and ultimately lead to the discovery of new cancer drugs.”

Dr Barford and his colleagues detailed their discovery in Nature.

The researchers reconstituted human APC/C and used a combination of electron microscopy and imaging software to visualize it at a resolution of less than a billionth of a meter.

The resolution was so fine that it allowed the team to see the secondary structure—the set of basic building blocks that combine to form every protein. Alpha-helix rods and folded beta-sheet constructions were clearly visible within the 20 subunits of the APC/C, defining the overall architecture of the complex.

Previous studies led by the same team had shown a globular structure for APC/C in much lower resolution, but the secondary structure had not been mapped.

Each of the APC/C’s subunits bond and mesh with other units at different points in the cell cycle, allowing it to control a range of mitotic processes, including the initiation of DNA replication, the segregation of chromosomes along spindles, and cytokinesis. Disrupting each of these processes could selectively kill cancer cells or prevent them from dividing.

“The fantastic insights into molecular structure provided by this study are a vivid illustration of the critical role played by fundamental cell biology in cancer research,” said Paul Workman, PhD, of The Institute of Cancer Research, London.

“The new study is a major step forward in our understanding of cell division. When this process goes awry, it is a critical difference that separates cancer cells from their healthy counterparts. Understanding exactly how cancer cells divide inappropriately is crucial to the discovery of innovative cancer treatments to improve outcomes for cancer patients.”

Image showing mitosis, with

the endoplasmic reticulum

in green, mitochondria in red,

and chromosomes in blue

Credit: Wellcome Images

Researchers say they’ve uncovered the structure of one of the most important protein complexes involved in cell division, and their finding has implications for cancer treatment.

The team mapped the anaphase-promoting complex (APC/C), which performs a wide range of tasks associated with mitosis.

The researchers believe that seeing APC/C in unprecedented detail could transform our understanding of how cells divide and reveal binding sites for future cancer drugs.

“It’s very rewarding to finally tie down the detailed structure of this important protein, which is both one of the most important and most complicated found in all of nature,” said David Barford, DPhil, of the Medical Research Council Laboratory of Molecular Biology in Cambridge, UK.

“We hope our discovery will open up whole new avenues of research that increase our understanding of the process of mitosis and ultimately lead to the discovery of new cancer drugs.”

Dr Barford and his colleagues detailed their discovery in Nature.

The researchers reconstituted human APC/C and used a combination of electron microscopy and imaging software to visualize it at a resolution of less than a billionth of a meter.

The resolution was so fine that it allowed the team to see the secondary structure—the set of basic building blocks that combine to form every protein. Alpha-helix rods and folded beta-sheet constructions were clearly visible within the 20 subunits of the APC/C, defining the overall architecture of the complex.

Previous studies led by the same team had shown a globular structure for APC/C in much lower resolution, but the secondary structure had not been mapped.

Each of the APC/C’s subunits bond and mesh with other units at different points in the cell cycle, allowing it to control a range of mitotic processes, including the initiation of DNA replication, the segregation of chromosomes along spindles, and cytokinesis. Disrupting each of these processes could selectively kill cancer cells or prevent them from dividing.

“The fantastic insights into molecular structure provided by this study are a vivid illustration of the critical role played by fundamental cell biology in cancer research,” said Paul Workman, PhD, of The Institute of Cancer Research, London.

“The new study is a major step forward in our understanding of cell division. When this process goes awry, it is a critical difference that separates cancer cells from their healthy counterparts. Understanding exactly how cancer cells divide inappropriately is crucial to the discovery of innovative cancer treatments to improve outcomes for cancer patients.”

HIV budding from a lymphocyte

Credit: CDC

MELBOURNE—Two men with hematologic malignancies who were also HIV-positive appear to be free of the virus after receiving stem cell transplants.

The patients have undetectable levels of HIV and remain free of their cancers—acute myeloid leukemia and non-Hodgkin lymphoma—more than 3 years after their transplants.

Importantly, the patients’ stem cell donors were not homozygous for CCR5-delta 32, a mutation that affords protection against HIV.

The researchers said these results herald a new direction in HIV research and provide hope for HIV-positive patients with leukemia and lymphoma.

The work was presented at the “Towards an HIV Cure Symposium,” which is part of the 20th International AIDS Conference.

Both patients were treated at St Vincent’s Hospital in partnership with the University of New South Wales’s Kirby Institute in Sydney, Australia.

One patient underwent a transplant in 2010 to treat his non-Hodgkin lymphoma, and his donor had 1 copy of CCR5-delta 32.

The second patient underwent a similar procedure for acute myeloid leukemia in 2011, and his donor did not have any copies of CCR5-delta 32.

Nevertheless, both patients were successfully cleared of HIV, although they remain on antiretroviral therapy as a protective measure.

“We’re so pleased that both patients are doing reasonably well years after the treatment for their cancers and remain free of both the original cancer and the HIV virus,” said David Cooper, MBBS, MD, DSc, of the Kirby Institute and St Vincent’s Hospital.

Until now, the only person considered to have cleared HIV is an American man, Timothy Ray Brown, who underwent 2 stem cell transplants in Berlin (in 2007 and 2008).

The cells in his second transplant included both copies of CCR5-delta 32, which affords protection against HIV and is found in less than 1% of the population. The man is no longer on antiretroviral therapy and remains free of HIV.

In Boston, 2 other patients underwent similar transplants in 2012, but the donor cells did not contain CCR5-delta 32. In both cases, HIV returned after antiretroviral treatment was stopped.

“It is very difficult to find a match for bone marrow donors and even more so to find one that affords protective immunity against HIV,” Dr Cooper said.

While his group’s results are a significant development, the researchers stressed that transplants are not a general functional “cure” for the up to 38.8 million people infected with HIV worldwide.

“This is a terrific, unexpected result for people with malignancy and HIV,” said Sam Milliken, MBBS, of St Vincent’s Hospital. “It may well give us a whole new insight into HIV, using the principles of stem cell transplantation.”

“It is important to caution that, at this stage, this form of treatment is far too dangerous for treating patients with HIV alone, but there may be potential for using transplants as an effective treatment modality for HIV down the track.”

The researchers said the 2 Sydney patients will be the subject of investigations to determine where any residual virus might be hiding and how it can be controlled. And the patients’ results point to a new direction for HIV research.

“We still don’t know why these patients have undetectable viral loads,” said Kersten Koelsch, MD, of the Kirby Institute. “One theory is that the induction therapy helps to destroy the cells in which the virus is hiding and that any remaining infected cells are destroyed by the patient’s new immune system.”

“We need more research to establish why and how bone marrow transplantation clears the virus. We also want to explore the predictors of sustained viral clearance and how this might be able to be exploited without the need for bone marrow transplantation.”

For the time being, the results mean that more patients who are eligible for transplant might be able to participate in clinical trials to determine the value of this procedure in HIV.

HIV budding from a lymphocyte

Credit: CDC

MELBOURNE—Two men with hematologic malignancies who were also HIV-positive appear to be free of the virus after receiving stem cell transplants.

The patients have undetectable levels of HIV and remain free of their cancers—acute myeloid leukemia and non-Hodgkin lymphoma—more than 3 years after their transplants.

Importantly, the patients’ stem cell donors were not homozygous for CCR5-delta 32, a mutation that affords protection against HIV.

The researchers said these results herald a new direction in HIV research and provide hope for HIV-positive patients with leukemia and lymphoma.

The work was presented at the “Towards an HIV Cure Symposium,” which is part of the 20th International AIDS Conference.

Both patients were treated at St Vincent’s Hospital in partnership with the University of New South Wales’s Kirby Institute in Sydney, Australia.

One patient underwent a transplant in 2010 to treat his non-Hodgkin lymphoma, and his donor had 1 copy of CCR5-delta 32.

The second patient underwent a similar procedure for acute myeloid leukemia in 2011, and his donor did not have any copies of CCR5-delta 32.

Nevertheless, both patients were successfully cleared of HIV, although they remain on antiretroviral therapy as a protective measure.

“We’re so pleased that both patients are doing reasonably well years after the treatment for their cancers and remain free of both the original cancer and the HIV virus,” said David Cooper, MBBS, MD, DSc, of the Kirby Institute and St Vincent’s Hospital.

Until now, the only person considered to have cleared HIV is an American man, Timothy Ray Brown, who underwent 2 stem cell transplants in Berlin (in 2007 and 2008).

The cells in his second transplant included both copies of CCR5-delta 32, which affords protection against HIV and is found in less than 1% of the population. The man is no longer on antiretroviral therapy and remains free of HIV.

In Boston, 2 other patients underwent similar transplants in 2012, but the donor cells did not contain CCR5-delta 32. In both cases, HIV returned after antiretroviral treatment was stopped.

“It is very difficult to find a match for bone marrow donors and even more so to find one that affords protective immunity against HIV,” Dr Cooper said.

While his group’s results are a significant development, the researchers stressed that transplants are not a general functional “cure” for the up to 38.8 million people infected with HIV worldwide.

“This is a terrific, unexpected result for people with malignancy and HIV,” said Sam Milliken, MBBS, of St Vincent’s Hospital. “It may well give us a whole new insight into HIV, using the principles of stem cell transplantation.”

“It is important to caution that, at this stage, this form of treatment is far too dangerous for treating patients with HIV alone, but there may be potential for using transplants as an effective treatment modality for HIV down the track.”

The researchers said the 2 Sydney patients will be the subject of investigations to determine where any residual virus might be hiding and how it can be controlled. And the patients’ results point to a new direction for HIV research.

“We still don’t know why these patients have undetectable viral loads,” said Kersten Koelsch, MD, of the Kirby Institute. “One theory is that the induction therapy helps to destroy the cells in which the virus is hiding and that any remaining infected cells are destroyed by the patient’s new immune system.”

“We need more research to establish why and how bone marrow transplantation clears the virus. We also want to explore the predictors of sustained viral clearance and how this might be able to be exploited without the need for bone marrow transplantation.”

For the time being, the results mean that more patients who are eligible for transplant might be able to participate in clinical trials to determine the value of this procedure in HIV.

HIV budding from a lymphocyte

Credit: CDC

MELBOURNE—Two men with hematologic malignancies who were also HIV-positive appear to be free of the virus after receiving stem cell transplants.

The patients have undetectable levels of HIV and remain free of their cancers—acute myeloid leukemia and non-Hodgkin lymphoma—more than 3 years after their transplants.

Importantly, the patients’ stem cell donors were not homozygous for CCR5-delta 32, a mutation that affords protection against HIV.

The researchers said these results herald a new direction in HIV research and provide hope for HIV-positive patients with leukemia and lymphoma.

The work was presented at the “Towards an HIV Cure Symposium,” which is part of the 20th International AIDS Conference.

Both patients were treated at St Vincent’s Hospital in partnership with the University of New South Wales’s Kirby Institute in Sydney, Australia.

One patient underwent a transplant in 2010 to treat his non-Hodgkin lymphoma, and his donor had 1 copy of CCR5-delta 32.

The second patient underwent a similar procedure for acute myeloid leukemia in 2011, and his donor did not have any copies of CCR5-delta 32.

Nevertheless, both patients were successfully cleared of HIV, although they remain on antiretroviral therapy as a protective measure.

“We’re so pleased that both patients are doing reasonably well years after the treatment for their cancers and remain free of both the original cancer and the HIV virus,” said David Cooper, MBBS, MD, DSc, of the Kirby Institute and St Vincent’s Hospital.

Until now, the only person considered to have cleared HIV is an American man, Timothy Ray Brown, who underwent 2 stem cell transplants in Berlin (in 2007 and 2008).

The cells in his second transplant included both copies of CCR5-delta 32, which affords protection against HIV and is found in less than 1% of the population. The man is no longer on antiretroviral therapy and remains free of HIV.

In Boston, 2 other patients underwent similar transplants in 2012, but the donor cells did not contain CCR5-delta 32. In both cases, HIV returned after antiretroviral treatment was stopped.

“It is very difficult to find a match for bone marrow donors and even more so to find one that affords protective immunity against HIV,” Dr Cooper said.

While his group’s results are a significant development, the researchers stressed that transplants are not a general functional “cure” for the up to 38.8 million people infected with HIV worldwide.

“This is a terrific, unexpected result for people with malignancy and HIV,” said Sam Milliken, MBBS, of St Vincent’s Hospital. “It may well give us a whole new insight into HIV, using the principles of stem cell transplantation.”

“It is important to caution that, at this stage, this form of treatment is far too dangerous for treating patients with HIV alone, but there may be potential for using transplants as an effective treatment modality for HIV down the track.”

The researchers said the 2 Sydney patients will be the subject of investigations to determine where any residual virus might be hiding and how it can be controlled. And the patients’ results point to a new direction for HIV research.

“We still don’t know why these patients have undetectable viral loads,” said Kersten Koelsch, MD, of the Kirby Institute. “One theory is that the induction therapy helps to destroy the cells in which the virus is hiding and that any remaining infected cells are destroyed by the patient’s new immune system.”

“We need more research to establish why and how bone marrow transplantation clears the virus. We also want to explore the predictors of sustained viral clearance and how this might be able to be exploited without the need for bone marrow transplantation.”

For the time being, the results mean that more patients who are eligible for transplant might be able to participate in clinical trials to determine the value of this procedure in HIV.

MRI scanner

Self-assembling nanoparticles may help physicians diagnose cancers earlier, according to a study published in Angewandte Chemie.

The nanoparticles boost the effectiveness of magnetic resonance imaging (MRI) by specifically seeking out CXCR4 receptors, which are found in cancerous cells.

The iron oxide nanoparticles are coated with peptide ligands that target tumor sites. When the particles find a tumor, they begin to interact with the cancerous cells.

Cancer-specific matrix metalloproteinase biomarkers prompt the nanoparticles to self-assemble into larger particles. And these larger particles are more visible on an MRI scan.

Researchers used cancer cells and mouse models to compare the effects of the self-assembling nanoparticles in MRI scanning against commonly used imaging agents. The nanoparticles produced a more powerful signal and created a clearer image of the tumor.

The team said the nanoparticles increase the sensitivity of MRI scans and could ultimately improve physicians’ ability to detect cancerous cells at much earlier stages of development.

“By improving the sensitivity of an MRI examination, our aim is to help doctors spot something that might be cancerous much more quickly,” said study author Nicholas Long, PhD, of Imperial College London in the UK. “This would enable patients to receive effective treatment sooner, which would hopefully improve survival rates from cancer.”

In addition to improving the sensitivity of MRI scans, the nanoparticles also appear to be safe. Before testing and injecting the particles into mice, the researchers had to ensure the particles would not become so big as to cause damage.

The team injected the particles into a saline solution inside a petri dish and monitored their growth over a 4-hour period. The nanoparticles grew from 100 nm to 800 nm, which was still small enough not to cause any harm.

Now, the researchers are working to enhance the effectiveness of the nanoparticles. And they hope to test their design in a human trial within the next 3 to 5 years.

“We would like to improve the design to make it even easier for doctors to spot a tumor and for surgeons to then operate on it,” Dr Long said. “We’re now trying to add an extra optical signal so that the nanoparticle would light up with a luminescent probe once it had found its target. So, combined with the better MRI signal, it will make it even easier to identify tumors.”

MRI scanner

Self-assembling nanoparticles may help physicians diagnose cancers earlier, according to a study published in Angewandte Chemie.

The nanoparticles boost the effectiveness of magnetic resonance imaging (MRI) by specifically seeking out CXCR4 receptors, which are found in cancerous cells.

The iron oxide nanoparticles are coated with peptide ligands that target tumor sites. When the particles find a tumor, they begin to interact with the cancerous cells.

Cancer-specific matrix metalloproteinase biomarkers prompt the nanoparticles to self-assemble into larger particles. And these larger particles are more visible on an MRI scan.

Researchers used cancer cells and mouse models to compare the effects of the self-assembling nanoparticles in MRI scanning against commonly used imaging agents. The nanoparticles produced a more powerful signal and created a clearer image of the tumor.

The team said the nanoparticles increase the sensitivity of MRI scans and could ultimately improve physicians’ ability to detect cancerous cells at much earlier stages of development.

“By improving the sensitivity of an MRI examination, our aim is to help doctors spot something that might be cancerous much more quickly,” said study author Nicholas Long, PhD, of Imperial College London in the UK. “This would enable patients to receive effective treatment sooner, which would hopefully improve survival rates from cancer.”

In addition to improving the sensitivity of MRI scans, the nanoparticles also appear to be safe. Before testing and injecting the particles into mice, the researchers had to ensure the particles would not become so big as to cause damage.

The team injected the particles into a saline solution inside a petri dish and monitored their growth over a 4-hour period. The nanoparticles grew from 100 nm to 800 nm, which was still small enough not to cause any harm.

Now, the researchers are working to enhance the effectiveness of the nanoparticles. And they hope to test their design in a human trial within the next 3 to 5 years.

“We would like to improve the design to make it even easier for doctors to spot a tumor and for surgeons to then operate on it,” Dr Long said. “We’re now trying to add an extra optical signal so that the nanoparticle would light up with a luminescent probe once it had found its target. So, combined with the better MRI signal, it will make it even easier to identify tumors.”

MRI scanner

Self-assembling nanoparticles may help physicians diagnose cancers earlier, according to a study published in Angewandte Chemie.

The nanoparticles boost the effectiveness of magnetic resonance imaging (MRI) by specifically seeking out CXCR4 receptors, which are found in cancerous cells.

The iron oxide nanoparticles are coated with peptide ligands that target tumor sites. When the particles find a tumor, they begin to interact with the cancerous cells.

Cancer-specific matrix metalloproteinase biomarkers prompt the nanoparticles to self-assemble into larger particles. And these larger particles are more visible on an MRI scan.

Researchers used cancer cells and mouse models to compare the effects of the self-assembling nanoparticles in MRI scanning against commonly used imaging agents. The nanoparticles produced a more powerful signal and created a clearer image of the tumor.

The team said the nanoparticles increase the sensitivity of MRI scans and could ultimately improve physicians’ ability to detect cancerous cells at much earlier stages of development.

“By improving the sensitivity of an MRI examination, our aim is to help doctors spot something that might be cancerous much more quickly,” said study author Nicholas Long, PhD, of Imperial College London in the UK. “This would enable patients to receive effective treatment sooner, which would hopefully improve survival rates from cancer.”

In addition to improving the sensitivity of MRI scans, the nanoparticles also appear to be safe. Before testing and injecting the particles into mice, the researchers had to ensure the particles would not become so big as to cause damage.

The team injected the particles into a saline solution inside a petri dish and monitored their growth over a 4-hour period. The nanoparticles grew from 100 nm to 800 nm, which was still small enough not to cause any harm.

Now, the researchers are working to enhance the effectiveness of the nanoparticles. And they hope to test their design in a human trial within the next 3 to 5 years.

“We would like to improve the design to make it even easier for doctors to spot a tumor and for surgeons to then operate on it,” Dr Long said. “We’re now trying to add an extra optical signal so that the nanoparticle would light up with a luminescent probe once it had found its target. So, combined with the better MRI signal, it will make it even easier to identify tumors.”

Drug release in a cancer cell

Credit: PNAS

A new model suggests we should be targeting cancers’ weaknesses instead of their strengths.

An article in BioEssays proposes that cancers form when recently evolved genes are damaged, and cancer cells have to revert to using older, inappropriate genetic pathways.

So we should create treatments that take advantage of capabilities humans have developed more recently—such as the adaptive immune system—instead of trying to target older capabilities—such as the innate immune system and cell proliferation.

“The rapid proliferation of cancer cells is an ancient, default capability that became regulated during the evolution of multicellularity about a billion years ago,” said study author Charley Lineweaver, PhD, of The Australian National University in Canberra.

“Our model suggests that cancer progression is the accumulation of damage to the more recently acquired genes. Without the regulation of these recent genes, cell physiology reverts to earlier programs, such as unregulated cell proliferation.”

To develop their model, Dr Lineweaver and his colleagues turned to knowledge uncovered by genome sequencing in a range of our distant relatives, including fish, coral, and sponges.

This knowledge has allowed scientists to establish the order in which genes evolved and is the basis of the new therapeutic implications of the model, Dr Lineweaver said.

He noted that the standard model of cancer development suggests that selection produces the acquired capabilities of cancer—such as sustained proliferative signaling and evading apoptosis—and they evolve during the lifetime of the patient.

But Dr Lineweaver’s model suggests the capabilities of cancer are acquired atavisms. They are activated during early embryogenesis and wound healing and reactivated inappropriately during carcinogenesis.

The most recent capabilities—mammalian and vertebrate capabilities—are the least entrenched in cancer. So they should be targeted with therapy.

The older capabilities—last eukaryotic common ancestor (LECA) capabilities, stem eukaryote capabilities, and the earliest evolved capabilities—are maintained in cancer and are therefore difficult to target.

For example, some human ATP binding cassette (ABC) transporters are ancient, and some are quite recent. Dr Lineweaver and his colleagues found that older ABC proteins were more likely to be active in cancer.

So the researchers believe we should create treatments that can be expelled by the newer ABC transporters. That way, normal cells will expel the treatment, but cancer cells will not.

Another potential treatment avenue, according to Dr Lineweaver, is targeting the adaptive immune system.

“The adaptive immune system that humans have has evolved relatively recently, and it seems cancer cells do not have the ability to talk to and be protected by it,” he noted.

“The new therapeutic strategies we are proposing target these weaknesses. These strategies are very different from current therapies, which attack cancer’s strength—its ability to proliferate rapidly.”

Drug release in a cancer cell

Credit: PNAS

A new model suggests we should be targeting cancers’ weaknesses instead of their strengths.

An article in BioEssays proposes that cancers form when recently evolved genes are damaged, and cancer cells have to revert to using older, inappropriate genetic pathways.

So we should create treatments that take advantage of capabilities humans have developed more recently—such as the adaptive immune system—instead of trying to target older capabilities—such as the innate immune system and cell proliferation.

“The rapid proliferation of cancer cells is an ancient, default capability that became regulated during the evolution of multicellularity about a billion years ago,” said study author Charley Lineweaver, PhD, of The Australian National University in Canberra.

“Our model suggests that cancer progression is the accumulation of damage to the more recently acquired genes. Without the regulation of these recent genes, cell physiology reverts to earlier programs, such as unregulated cell proliferation.”

To develop their model, Dr Lineweaver and his colleagues turned to knowledge uncovered by genome sequencing in a range of our distant relatives, including fish, coral, and sponges.

This knowledge has allowed scientists to establish the order in which genes evolved and is the basis of the new therapeutic implications of the model, Dr Lineweaver said.

He noted that the standard model of cancer development suggests that selection produces the acquired capabilities of cancer—such as sustained proliferative signaling and evading apoptosis—and they evolve during the lifetime of the patient.

But Dr Lineweaver’s model suggests the capabilities of cancer are acquired atavisms. They are activated during early embryogenesis and wound healing and reactivated inappropriately during carcinogenesis.

The most recent capabilities—mammalian and vertebrate capabilities—are the least entrenched in cancer. So they should be targeted with therapy.

The older capabilities—last eukaryotic common ancestor (LECA) capabilities, stem eukaryote capabilities, and the earliest evolved capabilities—are maintained in cancer and are therefore difficult to target.

For example, some human ATP binding cassette (ABC) transporters are ancient, and some are quite recent. Dr Lineweaver and his colleagues found that older ABC proteins were more likely to be active in cancer.

So the researchers believe we should create treatments that can be expelled by the newer ABC transporters. That way, normal cells will expel the treatment, but cancer cells will not.

Another potential treatment avenue, according to Dr Lineweaver, is targeting the adaptive immune system.

“The adaptive immune system that humans have has evolved relatively recently, and it seems cancer cells do not have the ability to talk to and be protected by it,” he noted.

“The new therapeutic strategies we are proposing target these weaknesses. These strategies are very different from current therapies, which attack cancer’s strength—its ability to proliferate rapidly.”

Drug release in a cancer cell

Credit: PNAS

A new model suggests we should be targeting cancers’ weaknesses instead of their strengths.

An article in BioEssays proposes that cancers form when recently evolved genes are damaged, and cancer cells have to revert to using older, inappropriate genetic pathways.

So we should create treatments that take advantage of capabilities humans have developed more recently—such as the adaptive immune system—instead of trying to target older capabilities—such as the innate immune system and cell proliferation.

“The rapid proliferation of cancer cells is an ancient, default capability that became regulated during the evolution of multicellularity about a billion years ago,” said study author Charley Lineweaver, PhD, of The Australian National University in Canberra.

“Our model suggests that cancer progression is the accumulation of damage to the more recently acquired genes. Without the regulation of these recent genes, cell physiology reverts to earlier programs, such as unregulated cell proliferation.”

To develop their model, Dr Lineweaver and his colleagues turned to knowledge uncovered by genome sequencing in a range of our distant relatives, including fish, coral, and sponges.

This knowledge has allowed scientists to establish the order in which genes evolved and is the basis of the new therapeutic implications of the model, Dr Lineweaver said.

He noted that the standard model of cancer development suggests that selection produces the acquired capabilities of cancer—such as sustained proliferative signaling and evading apoptosis—and they evolve during the lifetime of the patient.

But Dr Lineweaver’s model suggests the capabilities of cancer are acquired atavisms. They are activated during early embryogenesis and wound healing and reactivated inappropriately during carcinogenesis.

The most recent capabilities—mammalian and vertebrate capabilities—are the least entrenched in cancer. So they should be targeted with therapy.

The older capabilities—last eukaryotic common ancestor (LECA) capabilities, stem eukaryote capabilities, and the earliest evolved capabilities—are maintained in cancer and are therefore difficult to target.

For example, some human ATP binding cassette (ABC) transporters are ancient, and some are quite recent. Dr Lineweaver and his colleagues found that older ABC proteins were more likely to be active in cancer.

So the researchers believe we should create treatments that can be expelled by the newer ABC transporters. That way, normal cells will expel the treatment, but cancer cells will not.

Another potential treatment avenue, according to Dr Lineweaver, is targeting the adaptive immune system.

“The adaptive immune system that humans have has evolved relatively recently, and it seems cancer cells do not have the ability to talk to and be protected by it,” he noted.

“The new therapeutic strategies we are proposing target these weaknesses. These strategies are very different from current therapies, which attack cancer’s strength—its ability to proliferate rapidly.”

Adipose tissue

Preclinical research raises the prospect of more effective treatments for cachexia, a profound wasting of fat and muscle that can increase the risk of death in cancer patients.

In mouse models, an antibody effectively improved or prevented symptoms of cachexia.

The antibody inhibited the effects of parathyroid hormone-related protein (PTHrP), which is released from many types of cancer cells.

The researchers said their findings, published in Nature, are the first to explain in detail how PTHrP from tumors switches on a thermogenic process in fatty tissues, resulting in unhealthy weight loss.

The team carried out 2 experiments using mice that developed lung tumors and cachexia. In the first, a polyclonal antibody that specifically neutralizes PTHrP prevented cachexia almost completely, while untreated animals became mildly cachexic.

Anti-PTHrP treatment prevented the shrinkage of fat droplets. It blocked thermogenic gene expression in epididymal white adipose tissue, interscapular brown adipose tissue, and inguinal white adipose tissue, which suggests thermogenesis has a causal role in fat wasting.

Treatment with the anti-PTHrP antibody also lowered oxygen consumption in the mice, increased their physical activity, and reduced their heat production.

In the second experiment, the researchers treated mice with the anti-PTHrP antibody until they observed severe cachexia in control animals. The antibody significantly preserved muscle mass, which was evident by improved grip strength and in situ muscle contraction.

“You would have expected, based on our first experiments in cell culture, that blocking PTHrP in the mice would reduce browning of the fat,” said study author Bruce Spiegelman, PhD, of the Dana-Farber Cancer Institute in Boston.

“But we were surprised that it also affected the loss of muscle mass and improved health.”

Additional experiments, in which the researchers injected PTHrP into healthy and tumor-bearing mice, suggested that PTHrP alone doesn’t directly cause muscle wasting. But blocking the protein’s activity still prevents cachexia.

Thus, the role of PTHrP “is definitely not the whole answer” to the riddle of cachexia, Dr Spiegelman noted. Furthermore, it may turn out that the PTHrP mechanism is responsible for cachexia in only a subset of cancer patients.

The researchers analyzed blood samples from 47 cachexic patients with lung or colon cancer. And they found increased levels of PTHrP in 17 of the patients. Those patients had significantly lower lean body mass and were producing more heat energy at rest than the other patients in the group.

Dr Spiegelman noted that, before they test the anti-PTHrP antibody in clinical trials, clinicians would likely want to determine if the protein is elevated in certain cancers and determine which patients would be good candidates for the treatment.

Adipose tissue

Preclinical research raises the prospect of more effective treatments for cachexia, a profound wasting of fat and muscle that can increase the risk of death in cancer patients.

In mouse models, an antibody effectively improved or prevented symptoms of cachexia.

The antibody inhibited the effects of parathyroid hormone-related protein (PTHrP), which is released from many types of cancer cells.

The researchers said their findings, published in Nature, are the first to explain in detail how PTHrP from tumors switches on a thermogenic process in fatty tissues, resulting in unhealthy weight loss.

The team carried out 2 experiments using mice that developed lung tumors and cachexia. In the first, a polyclonal antibody that specifically neutralizes PTHrP prevented cachexia almost completely, while untreated animals became mildly cachexic.

Anti-PTHrP treatment prevented the shrinkage of fat droplets. It blocked thermogenic gene expression in epididymal white adipose tissue, interscapular brown adipose tissue, and inguinal white adipose tissue, which suggests thermogenesis has a causal role in fat wasting.

Treatment with the anti-PTHrP antibody also lowered oxygen consumption in the mice, increased their physical activity, and reduced their heat production.

In the second experiment, the researchers treated mice with the anti-PTHrP antibody until they observed severe cachexia in control animals. The antibody significantly preserved muscle mass, which was evident by improved grip strength and in situ muscle contraction.

“You would have expected, based on our first experiments in cell culture, that blocking PTHrP in the mice would reduce browning of the fat,” said study author Bruce Spiegelman, PhD, of the Dana-Farber Cancer Institute in Boston.

“But we were surprised that it also affected the loss of muscle mass and improved health.”

Additional experiments, in which the researchers injected PTHrP into healthy and tumor-bearing mice, suggested that PTHrP alone doesn’t directly cause muscle wasting. But blocking the protein’s activity still prevents cachexia.

Thus, the role of PTHrP “is definitely not the whole answer” to the riddle of cachexia, Dr Spiegelman noted. Furthermore, it may turn out that the PTHrP mechanism is responsible for cachexia in only a subset of cancer patients.

The researchers analyzed blood samples from 47 cachexic patients with lung or colon cancer. And they found increased levels of PTHrP in 17 of the patients. Those patients had significantly lower lean body mass and were producing more heat energy at rest than the other patients in the group.

Dr Spiegelman noted that, before they test the anti-PTHrP antibody in clinical trials, clinicians would likely want to determine if the protein is elevated in certain cancers and determine which patients would be good candidates for the treatment.

Adipose tissue

Preclinical research raises the prospect of more effective treatments for cachexia, a profound wasting of fat and muscle that can increase the risk of death in cancer patients.

In mouse models, an antibody effectively improved or prevented symptoms of cachexia.

The antibody inhibited the effects of parathyroid hormone-related protein (PTHrP), which is released from many types of cancer cells.

The researchers said their findings, published in Nature, are the first to explain in detail how PTHrP from tumors switches on a thermogenic process in fatty tissues, resulting in unhealthy weight loss.

The team carried out 2 experiments using mice that developed lung tumors and cachexia. In the first, a polyclonal antibody that specifically neutralizes PTHrP prevented cachexia almost completely, while untreated animals became mildly cachexic.

Anti-PTHrP treatment prevented the shrinkage of fat droplets. It blocked thermogenic gene expression in epididymal white adipose tissue, interscapular brown adipose tissue, and inguinal white adipose tissue, which suggests thermogenesis has a causal role in fat wasting.

Treatment with the anti-PTHrP antibody also lowered oxygen consumption in the mice, increased their physical activity, and reduced their heat production.

In the second experiment, the researchers treated mice with the anti-PTHrP antibody until they observed severe cachexia in control animals. The antibody significantly preserved muscle mass, which was evident by improved grip strength and in situ muscle contraction.

“You would have expected, based on our first experiments in cell culture, that blocking PTHrP in the mice would reduce browning of the fat,” said study author Bruce Spiegelman, PhD, of the Dana-Farber Cancer Institute in Boston.

“But we were surprised that it also affected the loss of muscle mass and improved health.”

Additional experiments, in which the researchers injected PTHrP into healthy and tumor-bearing mice, suggested that PTHrP alone doesn’t directly cause muscle wasting. But blocking the protein’s activity still prevents cachexia.

Thus, the role of PTHrP “is definitely not the whole answer” to the riddle of cachexia, Dr Spiegelman noted. Furthermore, it may turn out that the PTHrP mechanism is responsible for cachexia in only a subset of cancer patients.

The researchers analyzed blood samples from 47 cachexic patients with lung or colon cancer. And they found increased levels of PTHrP in 17 of the patients. Those patients had significantly lower lean body mass and were producing more heat energy at rest than the other patients in the group.

Dr Spiegelman noted that, before they test the anti-PTHrP antibody in clinical trials, clinicians would likely want to determine if the protein is elevated in certain cancers and determine which patients would be good candidates for the treatment.

 

 

Patient receiving chemotherapy

Credit: Rhoda Baer

 

Differences in treatment access and quality may explain why survival rates vary widely for European patients with hematologic malignancies, researchers have reported in The Lancet Oncology.

“The good news is that 5-year survival for most cancers of the blood has increased over the past 11 years, most likely reflecting the approval of new targeted drugs in the early 2000s . . . ,” said Milena Sant, MD, of the Fondazione IRCCS Istituto Nazionale dei Tumori in Milan, Italy.

“But there continue to be persistent differences between regions. For example, the uptake and use of new technologies and effective treatments has been far slower in eastern Europe than other regions. This might have contributed to the large differences in the management and outcomes of patients.”

Dr Sant and her colleagues uncovered these differences by analyzing data from 30 cancer registries covering all patients diagnosed in 20 European countries.*

The researchers compared changes in 5-year survival for 560,444 adults (aged 15 years and older) who were diagnosed with 11 lymphoid and myeloid cancers between 1997 and 2008, and followed up to the end of 2008.

Some cancers have shown particularly large increases in survival between 1997-1999 and 2006-2008, such as follicular lymphoma (59% to 74%), diffuse large B-cell lymphoma (42% to 55%), chronic myeloid leukemia (32% to 54%), and acute promyelocytic leukemia (50% to 62%).

The greatest improvements in survival have been in northern, central, and eastern Europe, even though adults in eastern Europe (where survival in 1997 was the lowest) continue to have lower survival for most hematologic malignancies than elsewhere.

Survival gains have been lower in southern Europe and the UK. For example, improvements in 5-year chronic myeloid leukemia survival in northern Europe (29% to 60%) and central Europe (34% to 65%) have been persistently higher than in the UK (35% to 56%) and southern Europe (37% to 55%).

Overall, the risk of death within 5 years from diagnosis fell significantly for all malignancies except myelodysplastic syndromes. But not all regions have seen such improvements.

For example, compared with the UK, the excess risk of death was significantly higher in eastern Europe than in other regions for most of the cancers investigated, but significantly lower in northern Europe.

The researchers said the most likely reasons for continuing geographical differences in survival are inequalities in the provision of care and in the availability and use of new treatments.

“We know that rituximab, imatinib, thalidomide, and bortezomib were first made available for general use in Europe in 1997, 2001, 1998, and 2003, respectively,” the researchers wrote.

“The years following general release of these drugs coincided with large increases in survival for chronic myeloid leukemia, diffuse large B-cell lymphoma, and follicular lymphoma, with a smaller but still significant survival increase for multiple myeloma plasmacytoma.”

However, they pointed out that the uptake and use of these drugs has not been uniform across Europe. For example, market uptake of rituximab, imatinib, and bortezomib was lower in eastern Europe than elsewhere and might explain the consistently lower survival in this region.

Writing in a linked comment article, Alastair Munro, MD, of the University of Dundee Medical School in Scotland, questioned whether improvements in survival can be attributed to drugs alone.

He said that better understanding of the conclusions from this study (called EUROCARE-5) requires additional information about changes affecting survival according to disease categories, the distribution of histological subtypes and their relation with the age distribution of the population, the distribution of stages at diagnosis, and the timing of active intervention for indolent tumors.

*The areas included in the study were northern Europe (Denmark, Iceland, and Norway), the UK (England, Northern Ireland, Scotland, and Wales), central Europe (Austria, France, Germany, Switzerland, and The Netherlands), eastern Europe (Bulgaria, Estonia, Lithuania, Poland, and Slovakia), and southern Europe (Italy, Malta, and Slovenia).

 

 

Patient receiving chemotherapy

Credit: Rhoda Baer

 

Differences in treatment access and quality may explain why survival rates vary widely for European patients with hematologic malignancies, researchers have reported in The Lancet Oncology.

“The good news is that 5-year survival for most cancers of the blood has increased over the past 11 years, most likely reflecting the approval of new targeted drugs in the early 2000s . . . ,” said Milena Sant, MD, of the Fondazione IRCCS Istituto Nazionale dei Tumori in Milan, Italy.

“But there continue to be persistent differences between regions. For example, the uptake and use of new technologies and effective treatments has been far slower in eastern Europe than other regions. This might have contributed to the large differences in the management and outcomes of patients.”

Dr Sant and her colleagues uncovered these differences by analyzing data from 30 cancer registries covering all patients diagnosed in 20 European countries.*

The researchers compared changes in 5-year survival for 560,444 adults (aged 15 years and older) who were diagnosed with 11 lymphoid and myeloid cancers between 1997 and 2008, and followed up to the end of 2008.

Some cancers have shown particularly large increases in survival between 1997-1999 and 2006-2008, such as follicular lymphoma (59% to 74%), diffuse large B-cell lymphoma (42% to 55%), chronic myeloid leukemia (32% to 54%), and acute promyelocytic leukemia (50% to 62%).

The greatest improvements in survival have been in northern, central, and eastern Europe, even though adults in eastern Europe (where survival in 1997 was the lowest) continue to have lower survival for most hematologic malignancies than elsewhere.

Survival gains have been lower in southern Europe and the UK. For example, improvements in 5-year chronic myeloid leukemia survival in northern Europe (29% to 60%) and central Europe (34% to 65%) have been persistently higher than in the UK (35% to 56%) and southern Europe (37% to 55%).

Overall, the risk of death within 5 years from diagnosis fell significantly for all malignancies except myelodysplastic syndromes. But not all regions have seen such improvements.

For example, compared with the UK, the excess risk of death was significantly higher in eastern Europe than in other regions for most of the cancers investigated, but significantly lower in northern Europe.

The researchers said the most likely reasons for continuing geographical differences in survival are inequalities in the provision of care and in the availability and use of new treatments.

“We know that rituximab, imatinib, thalidomide, and bortezomib were first made available for general use in Europe in 1997, 2001, 1998, and 2003, respectively,” the researchers wrote.

“The years following general release of these drugs coincided with large increases in survival for chronic myeloid leukemia, diffuse large B-cell lymphoma, and follicular lymphoma, with a smaller but still significant survival increase for multiple myeloma plasmacytoma.”

However, they pointed out that the uptake and use of these drugs has not been uniform across Europe. For example, market uptake of rituximab, imatinib, and bortezomib was lower in eastern Europe than elsewhere and might explain the consistently lower survival in this region.

Writing in a linked comment article, Alastair Munro, MD, of the University of Dundee Medical School in Scotland, questioned whether improvements in survival can be attributed to drugs alone.

He said that better understanding of the conclusions from this study (called EUROCARE-5) requires additional information about changes affecting survival according to disease categories, the distribution of histological subtypes and their relation with the age distribution of the population, the distribution of stages at diagnosis, and the timing of active intervention for indolent tumors.

*The areas included in the study were northern Europe (Denmark, Iceland, and Norway), the UK (England, Northern Ireland, Scotland, and Wales), central Europe (Austria, France, Germany, Switzerland, and The Netherlands), eastern Europe (Bulgaria, Estonia, Lithuania, Poland, and Slovakia), and southern Europe (Italy, Malta, and Slovenia).

 

 

Patient receiving chemotherapy

Credit: Rhoda Baer

 

Differences in treatment access and quality may explain why survival rates vary widely for European patients with hematologic malignancies, researchers have reported in The Lancet Oncology.

“The good news is that 5-year survival for most cancers of the blood has increased over the past 11 years, most likely reflecting the approval of new targeted drugs in the early 2000s . . . ,” said Milena Sant, MD, of the Fondazione IRCCS Istituto Nazionale dei Tumori in Milan, Italy.

“But there continue to be persistent differences between regions. For example, the uptake and use of new technologies and effective treatments has been far slower in eastern Europe than other regions. This might have contributed to the large differences in the management and outcomes of patients.”

Dr Sant and her colleagues uncovered these differences by analyzing data from 30 cancer registries covering all patients diagnosed in 20 European countries.*

The researchers compared changes in 5-year survival for 560,444 adults (aged 15 years and older) who were diagnosed with 11 lymphoid and myeloid cancers between 1997 and 2008, and followed up to the end of 2008.

Some cancers have shown particularly large increases in survival between 1997-1999 and 2006-2008, such as follicular lymphoma (59% to 74%), diffuse large B-cell lymphoma (42% to 55%), chronic myeloid leukemia (32% to 54%), and acute promyelocytic leukemia (50% to 62%).

The greatest improvements in survival have been in northern, central, and eastern Europe, even though adults in eastern Europe (where survival in 1997 was the lowest) continue to have lower survival for most hematologic malignancies than elsewhere.

Survival gains have been lower in southern Europe and the UK. For example, improvements in 5-year chronic myeloid leukemia survival in northern Europe (29% to 60%) and central Europe (34% to 65%) have been persistently higher than in the UK (35% to 56%) and southern Europe (37% to 55%).

Overall, the risk of death within 5 years from diagnosis fell significantly for all malignancies except myelodysplastic syndromes. But not all regions have seen such improvements.

For example, compared with the UK, the excess risk of death was significantly higher in eastern Europe than in other regions for most of the cancers investigated, but significantly lower in northern Europe.

The researchers said the most likely reasons for continuing geographical differences in survival are inequalities in the provision of care and in the availability and use of new treatments.

“We know that rituximab, imatinib, thalidomide, and bortezomib were first made available for general use in Europe in 1997, 2001, 1998, and 2003, respectively,” the researchers wrote.

“The years following general release of these drugs coincided with large increases in survival for chronic myeloid leukemia, diffuse large B-cell lymphoma, and follicular lymphoma, with a smaller but still significant survival increase for multiple myeloma plasmacytoma.”

However, they pointed out that the uptake and use of these drugs has not been uniform across Europe. For example, market uptake of rituximab, imatinib, and bortezomib was lower in eastern Europe than elsewhere and might explain the consistently lower survival in this region.

Writing in a linked comment article, Alastair Munro, MD, of the University of Dundee Medical School in Scotland, questioned whether improvements in survival can be attributed to drugs alone.

He said that better understanding of the conclusions from this study (called EUROCARE-5) requires additional information about changes affecting survival according to disease categories, the distribution of histological subtypes and their relation with the age distribution of the population, the distribution of stages at diagnosis, and the timing of active intervention for indolent tumors.

*The areas included in the study were northern Europe (Denmark, Iceland, and Norway), the UK (England, Northern Ireland, Scotland, and Wales), central Europe (Austria, France, Germany, Switzerland, and The Netherlands), eastern Europe (Bulgaria, Estonia, Lithuania, Poland, and Slovakia), and southern Europe (Italy, Malta, and Slovenia).

Berries are rich in antioxidants

Two researchers have offered an explanation as to why antioxidants are not effective in fighting cancers and suggested a way to change that.

The duo proposed that antioxidants from supplements or dietary sources are proving ineffective because they are not acting where reactive oxygen species (ROS) are produced.

So therapies that directly inhibit the production of mitochondrial- and NADPH oxidase-derived ROS, or that scavenge ROS at these sites, may be more effective.

David Tuveson, MD, PhD, of the Cold Spring Harbor Laboratory in New York, and Navdeep S. Chandel, PhD, of the Feinberg School of Medicine at Northwestern University in Chicago, detailed these theories in a report published in The New England Journal of Medicine.

The pair’s insights are based on recent advances in understanding the cell system that establishes a natural balance between oxidizing and antioxidizing compounds.

Oxidants like hydrogen peroxide are manufactured within cells and are essential in small quantities. But oxidants are toxic in large amounts, and cells naturally generate their own antioxidants to neutralize oxidants.

It has seemed logical, therefore, to boost a person’s intake of antioxidants to counter the effects of hydrogen peroxide and other similarly toxic ROS. All the more because cancer cells are known to generate higher levels of ROS to help feed their abnormal growth.

However, Drs Tuveson and Chandel proposed that taking antioxidant pills or eating foods rich in antioxidants may be failing to show a beneficial effect against cancer because antioxidants do not act where tumor-promoting ROS are produced—at mitochondria.

Rather, supplements and dietary antioxidants tend to accumulate at scattered distant sites in the cell, “leaving tumor-promoting ROS relatively unperturbed.”

Therefore, the authors suggested therapies that directly inhibit the production of mitochondrial- and NADPH oxidase-derived ROS, or that scavenge ROS at these sites, will be more effective than dietary antioxidants.

An alternative approach

Drs Tuveson and Chandel also proposed an alternative approach: disabling antioxidants in cancer cells. They noted that quantities of both ROS and natural antioxidants are higher in cancer cells. The higher levels of antioxidants are a natural defense by cancer cells to keep their higher levels of oxidants in check so that growth can continue.

In fact, therapies that raise the levels of oxidants in cells can be beneficial, whereas those that act as antioxidants may further stimulate the cancer cells.

So the authors suggested that genetic or pharmacologic inhibition of antioxidant proteins—a concept tested successfully in rodent models of lung and pancreatic cancers—may be a useful therapeutic approach in humans.

The key challenge is to identify antioxidant proteins and pathways in cells that are used only by cancer cells and not by healthy cells. Impeding antioxidant production in healthy cells will upset the delicate redox balance upon which normal cellular function depends.

So it seems research is needed to profile antioxidant pathways in tumor and adjacent normal cells, to identify possible therapeutic targets.

Berries are rich in antioxidants

Two researchers have offered an explanation as to why antioxidants are not effective in fighting cancers and suggested a way to change that.

The duo proposed that antioxidants from supplements or dietary sources are proving ineffective because they are not acting where reactive oxygen species (ROS) are produced.

So therapies that directly inhibit the production of mitochondrial- and NADPH oxidase-derived ROS, or that scavenge ROS at these sites, may be more effective.

David Tuveson, MD, PhD, of the Cold Spring Harbor Laboratory in New York, and Navdeep S. Chandel, PhD, of the Feinberg School of Medicine at Northwestern University in Chicago, detailed these theories in a report published in The New England Journal of Medicine.

The pair’s insights are based on recent advances in understanding the cell system that establishes a natural balance between oxidizing and antioxidizing compounds.

Oxidants like hydrogen peroxide are manufactured within cells and are essential in small quantities. But oxidants are toxic in large amounts, and cells naturally generate their own antioxidants to neutralize oxidants.

It has seemed logical, therefore, to boost a person’s intake of antioxidants to counter the effects of hydrogen peroxide and other similarly toxic ROS. All the more because cancer cells are known to generate higher levels of ROS to help feed their abnormal growth.

However, Drs Tuveson and Chandel proposed that taking antioxidant pills or eating foods rich in antioxidants may be failing to show a beneficial effect against cancer because antioxidants do not act where tumor-promoting ROS are produced—at mitochondria.

Rather, supplements and dietary antioxidants tend to accumulate at scattered distant sites in the cell, “leaving tumor-promoting ROS relatively unperturbed.”

Therefore, the authors suggested therapies that directly inhibit the production of mitochondrial- and NADPH oxidase-derived ROS, or that scavenge ROS at these sites, will be more effective than dietary antioxidants.

An alternative approach

Drs Tuveson and Chandel also proposed an alternative approach: disabling antioxidants in cancer cells. They noted that quantities of both ROS and natural antioxidants are higher in cancer cells. The higher levels of antioxidants are a natural defense by cancer cells to keep their higher levels of oxidants in check so that growth can continue.

In fact, therapies that raise the levels of oxidants in cells can be beneficial, whereas those that act as antioxidants may further stimulate the cancer cells.

So the authors suggested that genetic or pharmacologic inhibition of antioxidant proteins—a concept tested successfully in rodent models of lung and pancreatic cancers—may be a useful therapeutic approach in humans.

The key challenge is to identify antioxidant proteins and pathways in cells that are used only by cancer cells and not by healthy cells. Impeding antioxidant production in healthy cells will upset the delicate redox balance upon which normal cellular function depends.

So it seems research is needed to profile antioxidant pathways in tumor and adjacent normal cells, to identify possible therapeutic targets.

Berries are rich in antioxidants

Two researchers have offered an explanation as to why antioxidants are not effective in fighting cancers and suggested a way to change that.

The duo proposed that antioxidants from supplements or dietary sources are proving ineffective because they are not acting where reactive oxygen species (ROS) are produced.

So therapies that directly inhibit the production of mitochondrial- and NADPH oxidase-derived ROS, or that scavenge ROS at these sites, may be more effective.

David Tuveson, MD, PhD, of the Cold Spring Harbor Laboratory in New York, and Navdeep S. Chandel, PhD, of the Feinberg School of Medicine at Northwestern University in Chicago, detailed these theories in a report published in The New England Journal of Medicine.

The pair’s insights are based on recent advances in understanding the cell system that establishes a natural balance between oxidizing and antioxidizing compounds.

Oxidants like hydrogen peroxide are manufactured within cells and are essential in small quantities. But oxidants are toxic in large amounts, and cells naturally generate their own antioxidants to neutralize oxidants.

It has seemed logical, therefore, to boost a person’s intake of antioxidants to counter the effects of hydrogen peroxide and other similarly toxic ROS. All the more because cancer cells are known to generate higher levels of ROS to help feed their abnormal growth.

However, Drs Tuveson and Chandel proposed that taking antioxidant pills or eating foods rich in antioxidants may be failing to show a beneficial effect against cancer because antioxidants do not act where tumor-promoting ROS are produced—at mitochondria.

Rather, supplements and dietary antioxidants tend to accumulate at scattered distant sites in the cell, “leaving tumor-promoting ROS relatively unperturbed.”

Therefore, the authors suggested therapies that directly inhibit the production of mitochondrial- and NADPH oxidase-derived ROS, or that scavenge ROS at these sites, will be more effective than dietary antioxidants.

An alternative approach

Drs Tuveson and Chandel also proposed an alternative approach: disabling antioxidants in cancer cells. They noted that quantities of both ROS and natural antioxidants are higher in cancer cells. The higher levels of antioxidants are a natural defense by cancer cells to keep their higher levels of oxidants in check so that growth can continue.

In fact, therapies that raise the levels of oxidants in cells can be beneficial, whereas those that act as antioxidants may further stimulate the cancer cells.

So the authors suggested that genetic or pharmacologic inhibition of antioxidant proteins—a concept tested successfully in rodent models of lung and pancreatic cancers—may be a useful therapeutic approach in humans.

The key challenge is to identify antioxidant proteins and pathways in cells that are used only by cancer cells and not by healthy cells. Impeding antioxidant production in healthy cells will upset the delicate redox balance upon which normal cellular function depends.

So it seems research is needed to profile antioxidant pathways in tumor and adjacent normal cells, to identify possible therapeutic targets.

Chromosomes in red

with telomeres in green

Credit: Claus Azzalin

Measuring the length and function of telomeres can help us predict prognosis in patients with chronic lymphocytic leukemia (CLL), according to research published in the British Journal of Haematology.

Investigators found that CLL patients with short, dysfunctional telomeres had a considerably poorer clinical outcome than those with long, functional telomeres.

“For the first time, confident predictions of clinical outcome can be made for individual CLL patients at diagnosis based on accurate analysis of the length of telomeres in cancer cells,” said Chris Pepper, PhD, who led the research at Cardiff University’s School of Medicine in the UK.

“This should prove enormously valuable to doctors, patients, and their families, and there is no reason why there should not be widespread implementation of this powerful prognostic tool in the near future.”

CLL progression is known to be sped up by the loss of telomeres, which cap the ends of chromosomes and protect them from damage when a cell divides. Every time a cell divides, telomeres get shorter.

When they become too short in a healthy cell, signals are sent to instruct the cell to stop dividing and die. But this “safety check” does not occur in CLL cells. Telomeres become so short that chromosomes are left exposed and are prone to fusing together during cell division, causing even larger DNA faults and even greater instability.

So Dr Pepper and his colleagues set out to identify the telomere length at which fusions start to occur in CLL patients.

The team measured telomeres in patient samples using single telomere length analysis (STELA) along with an experimentally derived definition of telomere dysfunction. They defined the upper telomere length threshold at which telomere fusions occur and used the mean of the telomere “fusogenic” range as a prognostic tool.

The researchers first analyzed samples from 200 CLL patients and found that patients with telomeres below the fusogenic mean had significantly shorter overall survival than patients with telomeres above the fusogenic mean (hazard ratio [HR]=13.2, P<0.0001). This was also true for patients with early stage disease (HR=19.3, P<0.0001).

The investigators confirmed this association by analyzing samples from an additional 121 CLL patients. The prognostic impact of telomere dysfunction was evident in the entire cohort (HR=7.4, P<0.0001) and among patients classified as Binet stage A (HR=8.9, P<0.0001).

The researchers also found they could use telomere dysfunction to accurately classify Binet stage A patients into an indolent disease group and a poor prognostic group. At 10 years, the survival rate was 91% in the favorable prognostic group and 13% in the poor prognostic group.

Of note, patients with telomeres above the fusogenic mean had superior prognosis regardless of their IGHV mutation status or cytogenetic risk group. And in a multivariate analysis, the telomere fusogenic mean was associated with the highest hazard of progression and death, independent of all other biomarkers.

“The accuracy of this test in predicting how a person’s disease will develop is unprecedented and, if confirmed in clinical trials, would help doctors decide on the best treatment courses for individual CLL patients,” said Matt Kaiser, PhD, Head of Research at Leukaemia & Lymphoma Research, which funded this study.

“Telomeres are known to play a part in the progress of other forms of cancer, so this type of testing could have far-reaching benefits.”

Chromosomes in red

with telomeres in green

Credit: Claus Azzalin

Measuring the length and function of telomeres can help us predict prognosis in patients with chronic lymphocytic leukemia (CLL), according to research published in the British Journal of Haematology.

Investigators found that CLL patients with short, dysfunctional telomeres had a considerably poorer clinical outcome than those with long, functional telomeres.

“For the first time, confident predictions of clinical outcome can be made for individual CLL patients at diagnosis based on accurate analysis of the length of telomeres in cancer cells,” said Chris Pepper, PhD, who led the research at Cardiff University’s School of Medicine in the UK.

“This should prove enormously valuable to doctors, patients, and their families, and there is no reason why there should not be widespread implementation of this powerful prognostic tool in the near future.”

CLL progression is known to be sped up by the loss of telomeres, which cap the ends of chromosomes and protect them from damage when a cell divides. Every time a cell divides, telomeres get shorter.

When they become too short in a healthy cell, signals are sent to instruct the cell to stop dividing and die. But this “safety check” does not occur in CLL cells. Telomeres become so short that chromosomes are left exposed and are prone to fusing together during cell division, causing even larger DNA faults and even greater instability.

So Dr Pepper and his colleagues set out to identify the telomere length at which fusions start to occur in CLL patients.

The team measured telomeres in patient samples using single telomere length analysis (STELA) along with an experimentally derived definition of telomere dysfunction. They defined the upper telomere length threshold at which telomere fusions occur and used the mean of the telomere “fusogenic” range as a prognostic tool.

The researchers first analyzed samples from 200 CLL patients and found that patients with telomeres below the fusogenic mean had significantly shorter overall survival than patients with telomeres above the fusogenic mean (hazard ratio [HR]=13.2, P<0.0001). This was also true for patients with early stage disease (HR=19.3, P<0.0001).

The investigators confirmed this association by analyzing samples from an additional 121 CLL patients. The prognostic impact of telomere dysfunction was evident in the entire cohort (HR=7.4, P<0.0001) and among patients classified as Binet stage A (HR=8.9, P<0.0001).

The researchers also found they could use telomere dysfunction to accurately classify Binet stage A patients into an indolent disease group and a poor prognostic group. At 10 years, the survival rate was 91% in the favorable prognostic group and 13% in the poor prognostic group.

Of note, patients with telomeres above the fusogenic mean had superior prognosis regardless of their IGHV mutation status or cytogenetic risk group. And in a multivariate analysis, the telomere fusogenic mean was associated with the highest hazard of progression and death, independent of all other biomarkers.

“The accuracy of this test in predicting how a person’s disease will develop is unprecedented and, if confirmed in clinical trials, would help doctors decide on the best treatment courses for individual CLL patients,” said Matt Kaiser, PhD, Head of Research at Leukaemia & Lymphoma Research, which funded this study.

“Telomeres are known to play a part in the progress of other forms of cancer, so this type of testing could have far-reaching benefits.”

Chromosomes in red

with telomeres in green

Credit: Claus Azzalin

Measuring the length and function of telomeres can help us predict prognosis in patients with chronic lymphocytic leukemia (CLL), according to research published in the British Journal of Haematology.

Investigators found that CLL patients with short, dysfunctional telomeres had a considerably poorer clinical outcome than those with long, functional telomeres.

“For the first time, confident predictions of clinical outcome can be made for individual CLL patients at diagnosis based on accurate analysis of the length of telomeres in cancer cells,” said Chris Pepper, PhD, who led the research at Cardiff University’s School of Medicine in the UK.

“This should prove enormously valuable to doctors, patients, and their families, and there is no reason why there should not be widespread implementation of this powerful prognostic tool in the near future.”

CLL progression is known to be sped up by the loss of telomeres, which cap the ends of chromosomes and protect them from damage when a cell divides. Every time a cell divides, telomeres get shorter.

When they become too short in a healthy cell, signals are sent to instruct the cell to stop dividing and die. But this “safety check” does not occur in CLL cells. Telomeres become so short that chromosomes are left exposed and are prone to fusing together during cell division, causing even larger DNA faults and even greater instability.

So Dr Pepper and his colleagues set out to identify the telomere length at which fusions start to occur in CLL patients.

The team measured telomeres in patient samples using single telomere length analysis (STELA) along with an experimentally derived definition of telomere dysfunction. They defined the upper telomere length threshold at which telomere fusions occur and used the mean of the telomere “fusogenic” range as a prognostic tool.

The researchers first analyzed samples from 200 CLL patients and found that patients with telomeres below the fusogenic mean had significantly shorter overall survival than patients with telomeres above the fusogenic mean (hazard ratio [HR]=13.2, P<0.0001). This was also true for patients with early stage disease (HR=19.3, P<0.0001).

The investigators confirmed this association by analyzing samples from an additional 121 CLL patients. The prognostic impact of telomere dysfunction was evident in the entire cohort (HR=7.4, P<0.0001) and among patients classified as Binet stage A (HR=8.9, P<0.0001).

The researchers also found they could use telomere dysfunction to accurately classify Binet stage A patients into an indolent disease group and a poor prognostic group. At 10 years, the survival rate was 91% in the favorable prognostic group and 13% in the poor prognostic group.

Of note, patients with telomeres above the fusogenic mean had superior prognosis regardless of their IGHV mutation status or cytogenetic risk group. And in a multivariate analysis, the telomere fusogenic mean was associated with the highest hazard of progression and death, independent of all other biomarkers.

“The accuracy of this test in predicting how a person’s disease will develop is unprecedented and, if confirmed in clinical trials, would help doctors decide on the best treatment courses for individual CLL patients,” said Matt Kaiser, PhD, Head of Research at Leukaemia & Lymphoma Research, which funded this study.

“Telomeres are known to play a part in the progress of other forms of cancer, so this type of testing could have far-reaching benefits.”