For the thousands of Americans diagnosed each year with oral squamous cell carcinoma, a cornerstone of their treatment is a chemotherapy drug called cisplatin. As potent as cisplatin is at killing tumor cells, a small subset often grow resistant to the drug and survive. This has left oncologists in great need of a second chemotherapy agent to kill the cisplatin-resistant cells. In the October 20 issue of the Journal of Biological Chemistry, National Institute of Dental and Craniofacial Research (NIDCR) grantees report that they may have the solution. It’s called PS-341, which belongs to a new class of chemotherapeutic drugs that can induce apoptosis, or programmed cell death, independently of conventional cancer therapy. In a series of laboratory experiments, the scientists found PS-341 “potently” triggered apoptosis in cultured oral squamous cell carcinoma cells that were known to be resistant to cisplatin. The scientists also worked out the biochemical details, showing PS-341 does its deadly deed through a novel signaling pathway that is activated as a stress response in the endoplasmic reticulum, the cytoplasmic organelle where proteins are synthesized. “Given the fact that chemoresistance is a significant problem in cancer therapy, our results suggest that PS-341 may offer a novel alternative for treating recurrent cancer patients.”
(Source: NIDCR Web site, Science News in Brief, November 14, 2006)
