HOUSTON - Red-blood-cell-boosting drugs used to treat anemia may undermine breast cancer treatment with Herceptin, a targeted therapy that blocks the cancer-promoting HER2 protein, researchers from The University of Texas MD Anderson Cancer Center report in the Nov. 16 edition of Cancer Cell.
"Our research indicates when the two drugs were used at the same time, Herceptin was less effective," said study senior author Zhen Fan, M.D., associate professor in MD Anderson's Department of Experimental Therapeutics.
Natural erythropoietin (EPO) controls the body's red blood cell production. Manufactured versions called erythropoietin-stimulating agents or recombinant erythropoietin treat anemia caused by kidney failure and cancer treatment.
"Recombinant erythropoietin is a great drug, and it's saved many lives," Fan said. "Some studies, however, have shown that the drug has effects on cancer cells. We wanted to see if recombinant erythropoietin thwarts Herceptin, based on our understanding of how the two drugs work."
The researchers tested their hypothesis using breast cancer mouse models, then followed up with laboratory experiments on cancer cell lines to work out the molecular details. A retrospective case control study of 111 breast cancer patients supported their findings from the mouse studies.
Human epidermal growth factor receptor-2 (HER2) is overexpressed in 25-30 percent of breast cancers. The drug trastuzumab, known commercially as Herceptin, is an antibody designed to block HER2. Because resistance develops, only about a third of HER2-positive patients respond to the drug.
The presence of functional erythropoietin receptors on HER2-positive breast cancer could be one resistance mechanism, Fan said.
"The whole idea with targeted therapy against the HER2 protein is to shut off the downstream molecular activity launched by HER2," Fan said. "Erythropoietin can activate similar dow
|Contact: Scott Merville|
University of Texas M. D. Anderson Cancer Center