Thursday, October 30, 2014
Sunday, October 26, 2014
Cancer-killing stem cells engineered in lab
Scientists from Harvard Medical School have discovered a way of turning stem cells into killing machines to fight brain cancer.
In experiments on mice, the stem cells were genetically engineered to produce and secrete toxins which kill brain tumours, without killing normal cells or themselves.
Researchers said the next stage was to test the procedure in humans.
A stem cell expert said this was "the future" of cancer treatment.
Dr Khalid ShahMassachusetts General Hospital and Harvard Medical School
We do see the toxins kill the cancer cells”
The study, published in the journal Stem Cells, was the work of scientists from Massachusetts General Hospital and the Harvard Stem Cell Institute.
For many years, they had been researching a stem-cell-based therapy for cancer, which would kill only tumour cells and no others.
They used genetic engineering to make stem cells that spewed out cancer-killing toxins, but, crucially, were also able to resist the effects of the poison they were producing.
They also posed no risk to normal, healthy cells.
In animal tests, the stem cells were surrounded in gel and placed at the site of the brain tumour after it had been removed.
Their cancer cells then died as they had no defence against the toxins.
Dr Khalid Shah, lead author and director of the molecular neurotherapy and imaging lab at Massachusetts General Hospital and Harvard Medical School, said the results were very positive.
"After doing all of the molecular analysis and imaging to track the inhibition of protein synthesis within brain tumours, we do see the toxins kill the cancer cells."
He added: "Cancer-killing toxins have been used with great success in a variety of blood cancers, but they don't work as well in solid tumours because the cancers aren't as accessible and the toxins have a short half-life."
But genetically engineering stem cells has changed all that, he said.
"Now, we have toxin-resistant stem cells that can make and release cancer-killing drugs."
Prof Chris MasonUniversity College London
This study shows you can attack solid tumours by putting mini pharmacies inside the patient...”
Chris Mason, professor of regenerative medicine at University College London, said: "This is a clever study, which signals the beginning of the next wave of therapies.
"It shows you can attack solid tumours by putting mini pharmacies inside the patient which deliver the toxic payload direct to the tumour.
"Cells can do so much. This is the way the future is going to be."
Nell Barrie, senior science information manager for Cancer Research UK, said it was an "ingenious approach".
"We urgently need better treatments for brain tumours and this could help direct treatment to exactly where it's needed.
"But so far the technique has only been tested in mice and on cancer cells in the lab, so much more work will need to be done before we'll know if it could help patients with brain tumours."
She said this type of research could help boost survival rates and bring much-needed progress for brain cancers.
Dr Shah now plans to test the technique using a number of different therapies on mice with glioblastoma, the most common brain tumour in human adults.
He hopes the therapies could be used in clinical trials within the next five years.
Thursday, October 23, 2014
Wednesday, August 27, 2014
Study Suggests Repurposing Anti-depressant Medication to Target Medulloblastoma
Sunday, August 24, 2014
CINCINNATI – An international research team reports in Nature Medicine a novel molecular pathway that causes an aggressive form of medulloblastoma, and suggests repurposing an anti-depressant medication to target the new pathway may help combat one of the most common brain cancers in children.
The multi-institutional group, led by scientists at Cancer and Blood Diseases Institute (CBDI) at Cincinnati Children’s Hospital Medical Center, publish their results in the journal’s online edition on Aug. 24. The researchers suggest their laboratory findings in mouse models of the disease could lead to a more targeted and effective molecular therapy that would also reduce the harmful side effects of current treatments, which include chemotherapy, radiation or surgery.
“Although current treatments improve survival rates, patients suffer severe side effects and relapse tumors carry mutations that resist treatment,” said lead investigator Q. Richard Lu, PhD, scientific director of the Brain Tumor Center, part of the CBDI at Cincinnati Children’s. “This underscores an urgent need for alternative targeted therapies, and we have identified a potent tumor suppressor that could help a subset of patients with an aggressive form of medulloblastoma.”
Using genetically-engineered mice to model human medulloblastoma, the authors identified a gene called GNAS that encodes a protein called Gsa. Gsa kicks off a signaling cascade that researchers found suppresses the initiation of an aggressive form of medulloblastoma driven by a protein called Sonic hedgehog – considered one of the most important molecules in tissue formation and development.
The scientists used an anti-depressant medication called Rolipram – approved for behavioral therapy for use in Europe and Japan – to treat mice that were engineered not to express the GNAS gene. Lack of GNAS allowed aggressive formation of medulloblastoma tumors in neural progenitor cells of the GNAS mutant mice.
Rolipram treatment in the mice elevated levels of a molecule called cAMP, which restored the GNAS-Gsa pathway’s tumor suppression function. This caused the tumors to shrink and subside. The study also suggests that elevating cAMP levels in cells enhances the potency of Sonic hedgehog inhibitors, currently being tested in clinical trials to fight tumor growth.
The scientists stressed that a significant amount of additional research is needed before their findings could become directly relevant to clinical treatment. The authors also caution that the effect of raising cAMP levels may depend on the type of cancer, and that laboratory results in mice do not always translate uniformly to humans.
Collaborating on the study with Dr. Lu was first author, Xuelian He (MD, a postdoctoral fellow), of the CBDI at Cincinnati Children’s and the West China Second Hospital, Sichuan University, in Chengdu, China.
Other collaborating institutions include: The Hospital for Sick Children, University of Toronto, Toronto; Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Pathology, Yonsei University College of Medicine, Seoul, Republic of Korea; the German Cancer Research Center, Heidelberg, Germany; the National Institute of Diabetes and Digestive and Kidney Diseases (NIH); Department of Neurology, Children’s Hospital, Dana-Farber Cancer Institute, Harvard Medical School, Boston; St. Jude Children’s Research Hospital, Memphis; departments of Pediatrics, Anatomy and Neurobiology, Washington University School of Medicine, St Louis; Tumor Development Program, Sanford-Burnham Medical Research Institute, La Jolla, Calif.
Funding support came in part from the National Institutes of Health (R01NS078092, R01NS075243) and the Canadian Institutes of Health Research.
About Cincinnati Children’s
Cincinnati Children’s Hospital Medical Center ranks third in the nation among all Honor Roll hospitals in U.S.News & World Report’s 2014 Best Children’s Hospitals. It is also ranked in the top 10 for all 10 pediatric specialties. Cincinnati Children’s, a non-profit organization, is one of the top three recipients of pediatric research grants from the National Institutes of Health, and a research and teaching affiliate of the University of Cincinnati College of Medicine. The medical center is internationally recognized for improving child health and transforming delivery of care through fully integrated, globally recognized research, education and innovation. Additional information can be found at www.cincinnatichildrens.org. Connect on the Cincinnati Children’s blog, via Facebook and on Twitter.