Enzyme Found Responsible for Survival of Cancer Cells

Researchers have discovered that a key enzyme, Pim-2, is responsible for the survival of cancer cells. The study is to appear in the August 1, 2003, issue of Genes & Development.

Using a microarray analysis of RNA in the immune systems of mice, researchers observed a mutated form of Pim-2 in high quantities in cases of prostate cancer, leukemia, and multiple myeloma. In the presence of Pim-2, 60% of cancer cells survived attempts to starve or kill the cell. Cancer cells survived for the maximum duration in the study, up to three weeks, regardless of whether or not growth factor was present.

Only after both the Akt pathway and Pim-2 pathway were dysregulated, were cancerous cells unable to survive and died. While Akt interacts with other enzymes to promote cell survival, the function of Pim-2 is independent. Akt is sensitive to rapamycin,, while Pim-2 is not. However, they do have some common factors, such as a phosphorylated "off signal” suppressor protein called 4E-BP1.

"Until now, predominant thinking has looked to the Akt pathway as the primary pathway for cancer cells. Now we know that Pim-2 plays an equally important role and is as much of a cancer-promoting gene, or oncogene, as Akt,” said principal investigator Craig Thompson, M.D., director of the Abramson Family Cancer Research Institute (AFCRI) at the University of Pennsylvania (Philadelphia, USA). "Our next step is to try and manipulate the action of Pim-2 so that we can interfere with the survival of cancer cells.”




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Abramson Family Cancer Research Institute (AFCRI) at the University of Pennsylvania