Scientists have taken another step in cellular reprogramming that points the way towards the use of a patient’s own cells to treat genetic diseases. In a proof of concept study, researchers took skin cells from patients with a rare condition, Fanconi anemia, which causes skeletal problems and bone-marrow failure, and raises sufferers’ risk of cancer [Technology Review]. In the skin cells, the researchers fixed the genetic defects that caused the disease, and then reprogrammed the cells to act like stem cells capable of growing into any type of tissue.
The corrected stem cells could be grown into blood precursor cells for therapy. As these would carry a patient’s own DNA, except for the mutation responsible for the illness, they could be transplanted without risk of rejection by the body’s immune system [Times Online]. However, the patched up cells were not used to treat patients in this study, because it isn’t yet clear whether such cells are safe. Comments molecular geneticist Chris Mathew: “In future it may become possible to transfer the corrected stem cells back into the patient, but much work remains to be done before this can be transferred from the lab bench to the bedside” [The Scientist].
Over the past year, such reprogrammed and multipurpose cells known as induced pluripotent stem (iPS) cells have been generated from patients with a wide variety of genetic disorders…. Such disease-specific stem cells offer unprecedented experimental models to investigate disease mechanisms and to screen new drug compounds. But to treat diseases with tailor-made cell therapies, such stem cells first need to be corrected to be disease-free [The Scientist].
In the new study, published in Nature, lead researcher Juan Carlos Izpisua Belmonte and his colleagues first used a lentivirus to deliver genes to the skin cells, which corrected the mutation that caused Fanconi anemia in the three patients. The team then tranformed the skin cells into iPS cells by using retroviruses to introduce four genes known to be active in embryo development, which in effect turned back the clock and made the adult skin cells behave like embryonic stem cells.
The technique isn’t ready for medical trials, researchers stress. “Serious concerns need addressing before attempting any clinical trial with iPS-derived cells; perhaps the most important is that of tumor formation,” says Belmonte. This is because the virally delivered genes used to reprogram the skin cells can remain embedded in the cell’s DNA even after reprogramming. These genes are thought to become active during the cell-differentiation process, considerably raising the long-term risk of cancer [Technology Review]. However, just last week another group of researchers announced a new way to reprogram skin cells that doesn’t involve the use of viruses, raising hopes that scientists will find ways to use patients’ own cells to fight their diseases.
Related Content:
80beats: A Safer Way to Transform Skin Cells Into Stem Cells Brings Medical Trials Closer
80beats: One Step Closer to Embryo-Free (and Controversy-Free) Stem Cells
80beats: Researchers Create Stem Cells Without Cancerous Side Effects
Image: Juan Carlos Izpisua Belmonte. A colony of the iPS cells created.
June 1st, 2009 at 8:42 pm
“raising hopes that scientists will find ways to use patients’ own cells to fight their diseases.”
I think it’s only a matter of time and how much money we through at the problem. When you think about it, with all the work that’s been done with stem cells so far, getting the proper DNA into a stem cell to not cause a cancer started by a viral vector is a relatively minor technical hurdle. Think about this: some of the first gene therapies were conducted back in the early 90s. (They didn’t go well, but the patients were dying anyway.) Our computing technology has doubled roughly 10 to 15 times since then. And will double again next year, and so on.
But hey, you never know when a game changer may come along – maybe nanotech will suddenly hit it’s stride and someone will invent a nanomachine that can repair DNA in situ and hunt/kill cancerous cells. This is complete wild speculation, I’m just saying that sometimes game changers come in that replace a very valid technology with something that just happens to do it way better. CRTs were a valid technology a few years back but good luck getting one today that isn’t made for some highly specialized function. CRTs were 50 years in the making, LCDs, what, 10, 20?
In any case, I look forward to living a good, long time – the kind of time that makes my grandparents seem like children to me. Hail Science!