New drug target for inducing apoptosis in abnormal cells published in cancer research
HORSHAM, PA (July 5, 2000) -- Scientists at Cell Pathways, Inc. (Nasdaq: CLPA) and their collaborators have identified a new drug target that may play a key role in cancer cell survival. Exisulind (Aptosyn) and other compounds in the company's family of selective apoptotic antineoplastic drugs (SAANDs) inhibit this target, cyclic GMP phosphodiesterases of the PDE5 and PDE2 gene families that have been found to be over-expressed in cancerous and precancerous cells of the colon. The inhibition of these target proteins triggers a chain of events which results in the programmed cell death, or apoptosis, of cancerous and precancerous cells, but not normal ones. The drugs have additionally been shown to inhibit the growth of a broad variety of malignant tumor cells beyond colon tumors, in both cell culture and animal models of human cancers.
The new research appears in the July 1 issue of the journal Cancer Research. Cell Pathways scientists and their collaborators at the University of South Alabama College of Medicine, and the University of Colorado authored the paper.
Apoptosis and SAANDs
Apoptosis is the body's response to a normal, orderly sequence of biochemical or physical signals by which damaged or "worn out" cells are eliminated to make way for healthy, new cells. When the mechanism of apoptosis goes awry, cells continue to multiply and grow inappropriately, forming a mass of tissue -- a cancerous tumor. In colon cancer, excessive cell growth occurs as the result of the accumulation of a regulatory protein, beta-catenin, caused by mutations in the adenomatous polyposis coli (APC) gene.
The researchers showed that exisulind and other SAANDs induce apoptosis in colon tumor cells by inhibiting the different forms of cGMP PDE in these cell lines. This results in a sustained increase in cGMP in the cells and the indu
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