Brain Cancer and Stem Cells

Brain Cancer and Stem Cells

Researchers at Preston Robert Tisch Brain Tumor Center at Duke University have identified stem-cell like glioma cells that expressed the growth factor VEGF generate the production of blood vessels that keep cancer cells alive and growing. This production of blood vessels is called angiogenesis.

The press release reports that the researchers identified the stem-cell like cells in tumors by use of known antibody markers. They then compared them to other tumor cells and found that these cells expressed more VEGF and formed more tumors with more blood vessels. When the VEGF activity was blocked with an antibody, the new blood vessel formation stopped and so did the tumor growth.

This research is not a way to cure brain cancer, but it does suggest that turning off the VEGF expression in the cancer stem cells could at least stop the progression of the disease. If it was combined with chemotherapy that killed the other cells, it might lead to a long-term remission.

It has been fairly well established at this point that a number of different kinds of cancers have cells with stem-cell like properties that may be causing the growth of the tumor cells and that are resistant to traditional chemotherapy because it targets cells based on their rate of division; the stem cells do not divide at the same rate the other tumor cells do. A lot of research has been done to identify these cells, but less has been successfully done so far to figure out what to do with them once found. Being able to inhibit key growth factors seems like a very important component of treatment.

The relationship between cancer and stem cells still consists of a large number of unknowns. Whether by synchronicity with this study or by design, UCSF Today published an article yesterday about cancer stem cells in general—take a peek if you are interested. There is also a cool stem cell photo and some links.

Retina Research

Retina Research

Scientists at the University of Washington have successfully used human embryonic stem cells to treat diseased portions of the retina in mice, according to an article in the Seattle Times. The research was done with one of the federally approved lines. Stem cells derived from mice have previously been shown to have an effect upon retinal damage, but this is reported to be the first time human ESCs have done so. The MIT Technology Review also has a story on the subject.

The major challenge of the research was finding the right combination of growth factors. The scientists used growth factors that contribute to the development of the head in humans and mice, and also used a growth factor that contributes to a large eye size in frogs. With this combination of growth factors, the cells developed into retinal progenitor cells about twice as fast as they would in utero. The new cells replaced damaged rods, cones, and amacrine cells in the retina. Being able to create cells that developed into photoreceptors is a significant step forward in treating eye disease with stem cells, as it has been very difficult to reliably get stem cells to differentiate into the right kind and number of eye cells.

The researchers hope that this might lead to a treatment for human retinal diseases, such as macular degeneration, within two years. (It would be used for degenerative diseases and not—at least so far—as a treatment for blindness caused by other factors.) They are watching for the results of a California biotech company (ACT in Alameda) that is using the same ESC line as they did in similar research. ACT hopes to start human trials by the end of next year.

The next step will be to transplant the stem cells into blind animals and to see if the blindness can be reversed. Treatments of the eye with stem cells are really important, not only because vision is such a key sense to people, but also because they may provide information about how to treat the degeneration of other kinds of neural tissue. Since the retina is essentially an extension of the nerves in the brain, what works for the retina might work for brain or spinal degeneration.

In a somewhat related story, the Glasgow Daily Record reported that a young Scotsman is going to have umbilical-cord derived stem cell treatment to try to cure a rare degenerative disease of the eye called Lebers. The stem cells will be injected into his arm and his temples. The procedure will take place at a clinic in Rotterdam which has claimed success with using umbilical stem cells to treat multiple sclerosis. Most neurologists do not believe the MS treatment actually works, so it will be interesting to see if there is a success in the treatment for the nerve damage this man has sustained.

Australian Update

Australian Update

The Sydney Morning Herald reported that John Howard will allow a conscience vote on expanding stem cell research, and that he was “surprised this morning by the depth of feeling within his party room…” He has been under pressure for a while to allow a conscience vote on the subject since the Lockhart report that was issued earlier this year recommended reducing the restrictions on embryonic stem cell researach.

There is still an issue as to in what form a bill will be brought to the floor of Parliament; one senator plans to introduce a private bill but under normal parliamentary procedure, it would need to be agreed to by the government for a vote to proceed. However, it appears that there are a number of voices calling for a free vote, and that Howard is hearing them.

Australia currently allows embryonic stem cell research on leftover IVF embryos. The new rules would permit therapeutic cloning. Another, very similar story was carried in The Age; it quoted one senator who is opposed to therapeutic cloning as saying that there should still be a debate on it.