Archive for September 24th, 2011

September 24, 2011

Stems cells are potential source of cancer-fighting T cells

The human immune system is, in principle, capable of killing cancer cells all by itself, without need for any extra drugs or doses of radiation. But that supposes the immune system is able to distinguish cancer cells from healthy body cells, since it’s not a good thing when the immune system targets healthy cells.

Stems cells are potential source of cancer-fighting T cells

Adult stem cells from mice converted to antigen-specific T cells — the immune cells that fight cancer tumor cells — show promise in cancer immunotherapy and may lead to a simpler, more efficient way to use the body’s immune system to fight cancer, according to Penn State College of Medicine researchers.

“Cancer immunotherapy is a promising method to treat cancer patients,” said Jianxsun Song, assistant professor of microbiology and immunology. “Tumors grow because patients lack the kind of antigen-specific T cells needed to kill the cancer. An approach called adoptive T cell immunotherapy generates the T cells outside the body, which are then used inside the body to target cancer cells.”

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September 24, 2011

Epigenetic changes don’t last

We just learned that epigenetic mutations occur much more rapidly than DNA mutations, in a study of methylation changes in Arabidopsis. And now it turns out that such epigenetic changes don’t actually last all that long – also from a study of methylation in Arabidopsis. The thing is that a methylation event can occur much more easily than a change in DNA base sequences – and the event is also much more easily undone. The implication is that epigenetics probably isn’t so important for long-term evolution after all.

Epigenetic changes don’t last – Max-Planck-Gesellschaft

Scientists at the Max Planck Institute of Developmental Biology in Germany have now produced the first comprehensive inventory of spontaneous epigenetic changes. Using Arabidopsis, the workhorse of modern plant genetics, the researchers determined how often and where in the genome epigenetic modifications occur – and how often they disappear again. They found that epigenetic changes are many orders of magnitude more frequent than conventional DNA mutations, but also often short lived. They are therefore probably much less important for long-term evolution than previously thought.

Further reading:

Spontaneous epigenetic variation in the Arabidopsis thaliana methylome