Two ovarian cancer discoveries
Two new findings are adding to the understanding of ovarian cancer. One takes an important step by identifying a target that inhibits cell division. The other identifies a protein that unexpectedly regulates the creation of new blood vessels that feed a tumor from outside.
Researchers in one study found that depleting Salt Inducible Kinase 2, known as SIK2, from ovarian cancers made the cancer cells sensitive to paclitaxel, a commonly prescribed chemotherapeutic agent that inhibits cell division, making the drug more effective in stopping the cancer’s growth.
“There’s a large window of opportunity to improve the effectiveness of existing chemotherapies by modifying the sensitivity of cancer cells to the drugs,” says study senior author Robert Bast Jr., M.D., professor and vice president for translational research at MD Anderson. “In our search for proteins that are responsible for that sensitivity, we found that SIK2 was required for cell division and that its inhibition offers a novel approach to improving chemotherapy for ovarian cancer that deserves further study.”
In the second study, a protein associated with cancer progression — when it is abundant inside of tumors — was discovered to also regulate the creation of new blood vessels that feed the tumor from outside. By using a nanoparticle-based, gene-silencing system to block production of the protein, the researchers inhibited formation of new blood vessels to the tumor and caused a steep reduction in tumor burden in a mouse model of ovarian cancer.
“We’ve discovered that EZH2 promotes tumor growth by shutting down genes that block formation of new blood vessels,” says study senior author Anil Sood, M.D., professor in the departments of Gynecologic Oncology and Cancer Biology. “Tumors treated with current anti-angiogenesis drugs eventually progress. The study presents a new mechanism for angiogenesis (blood vessel formation) that opens the door for development of new treatment approaches.”
EZH2 has been associated with the progression and spread of bladder, breast, prostate and gastric cancers, as well as one type of pharynx cancer.
Both studies reported in the August 2010 edition of Cancer Cell.