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© 2011, 2012 Health Futures Digest
| We said here years ago that RNA interference (RNAi, the ability to control whether and how genes express themselves) was the best thing since sliced bread. Someone at Nobel must have been thinking the same thing, since the two researchers credited with RNAi’s discovery have been awarded the 2006 Nobel Prize for Medicine. It is significant that they won the prize a mere eight years after their discovery — Nobels used to cook for decades before being awarded. It is another sign of the acceleration in medicine, as is an explosion in patent filings for gene therapies in recent years. Although this has lengthened the average patent process from 12 months to 30 months, it is a reflection of our accelerating understanding of genetics-linked disorders including — in just the past few months – the discovery of a gene reponsible for otitis media (“glue ear”) in children, a second gene associated with Crohn’s Disease. and a gene linked with autism.
Our increased understanding has contributed to a major breakthrough in the war on cancer and in the development of gene therapy, with the latter’s successful curing of two metastasized melanoma patients. To the extent gene therapy replaces chemotherapy, as it evidently has the potential to do, then it could render moot a sophisticated test to predict which chemotherpy regimen to apply to the individual patient. Another gene therapy success, which appears to utilize RNAi, could be a blockbuster HIV therapy, except that even if it turns out to work perfectly, it is unlikely to be available to the vast majority of impoverished HIV/AIDS victims. |
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| RNAi Nobel Prize
Craig Mello and Andrew Z. Fire shared the 2006 Nobel Prize in medicine for their discovery of the RNA interference (RNAi) process that can silence specific genes. It has not only become a standard lab procedure for studying gene expression, but also has therapeutic potential in diabetes, AIDS, cancer, heart disease, asthma, cystic fibrosis, the flu, Parkinson’s and Huntington’s disease, and age-related macular degeneration, a major cause of blindness. The volume of biotech patents has been “exploding” in recent years, reports Mark Hollmer in the Boston Business Journal. The growth is accounted for more by specific genetic-related treatments, rather than genetic discoveries themselves. Patents are no longer awarded just for discuovery of the genetic sequencing for a protein; now you also have to show what the protein does — what its utility is. Most of the 409,500+ US patents filed in 2005 (up from 344,717 in 2001) are classified as “utility patents.” The growth in applications has lengthened the application process from about 12 months to more than 30. Scientists believe they have found a gene that may be responsible for glue ear in children. The condition, also called otitis media, meaning inflammation of the middle ear, is the most common cause of hearing impairment in children. The work in mice, published in Public Library of Science Genetics, pinpoints a gene called Evi1. A variation of a gene recently discovered to contribute to the development of Crohn’s disease appears to protect people from developing the condition, reports Anita Srikameswaran in the Pittsburgh Post-Gazette. The jointUS-Canadian research team found three genetic markers strongly associated with the disease. Two of them occurred in the CARD15 gene identified five years ago, but the third marker was in a gene that makes a receptor protein for interleukin-23, which is involved in inflammation and in fending off infections. The protective variant of this latter gene was the biggest difference between the Crohn’s group and the healthy group studied and “is more common in the healthy population than it is in the Crohn’s disease cases, so it appears to confer protection against developing the disease,” a researcher said. More work is needed to establish how each variant influences inflammatory pathways. Eventually, the challenge will be understanding how the genes interact with each other and how they interact with the environment to cause the disease. Researchers at Vanderbilt have identified a gene mutation that more than doubles the risk of developing autism, though it does not cause the disease, reports Claudia Pinto in the Tennessean. Indeed, according to the researchers, no single gene causes it — between five and 20 genes appear to be involved. Therefore, identifying this one gene mutation is not enough to create a diagnostic tool, but as more contributory genes are identified, screening soon after birth could be possible in a few years. The “MET” gene, as it has been named, is present in 47 percent of the population, and while many of those who carry the mutated gene don’t have autism, they appear to be at greater risk of developing it. MET is different from the other autism contributor genes so far discovered in that it alone plays a role both in brain development and in immune system regulation and gastrointestinal repair, and thus may play a particular role in the proneness of autistic children to tummy aches, constipation, and colds. The Vanderbilt researchers also stress that autism can’t be entirely caused by genetics, but may be triggered by environmental factors. Cancer: Gene Therapy Breakthrough Normal white blood cells genetically re-engineered to become especially aggressive toward melanoma have cured two patients whose melanoma had already metastasized. The therapy could be useful against many other forms of cancer. US National Cancer Institute researchers used harmless viruses, engineered to carry a package of designer genes, to “infect” with the new genes healthy white blood cells taken from each patient. When the cells were transplanted back into the patient’s body, they begin to make a protein that targeted and destroyed the melanoma cells. The two patients (out of 17 treated) have been disease free for almost two years since the start of the treatment. The therapy had no effect on the other 15. Clearly, more work is needed to improve efficacy in more patients, but on the strength of the two successes the research team is sufficiently encouraged to have begun to develop other aggressive white blood cells in an attempt to treat other cancers and have already designed gene packages to target breast and lung cancers. In 2007 Duke University researchers will begin clinical trials in 120 breast cancer patients of a gene test which, in preliminary trials, has been 80 percent accurate in predicting the optimum chemotherapy regimen for individual cancer patients. Lead researcher Dr Anil Potti said: “Chemotherapy will likely continue to be the backbone of many anti-cancer strategies. With the new test, we think that physicians will be able to personalise chemotherapy in a way that should improve outcomes.” Gene Therapy for HIV Promising After five HIV patients who had not responded to antiretroviral drugs were treated with a disabled HIV virus engineered with genes to block HIV reproduction, HIV levels in their blood either stabilised or decreased. The phase I trial patients were given a single infusion of their own immune system T cells that had been removed from their blood and modified to carry the HIV gene re-engineered with an antisense RNA molecule which scrambles the process of reading genetic information and is designed to sabotage the process HIV uses to reproduce itself inside infected cells. This was a small and early trial, and any patients receiving the therapy will be monitored for 15 years to assess long-term effects. The editor of Aids Treatment Update pointed out to the BBC News that gene therapy was likely to be a labor-intensive, expensive treatment designed for individuals, and so not available to the vast majority of people with HIV/Aids who live in developing countries. The researchers are now recruiting for a second trial, this time among patients whose HIV load is already well controlled by antiretroviral drugs, to see if they can stay off the drugs, which do have significant side effects, for an extended period. |
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