A newly discovered biomarker for pancreatic cancer could provide a new avenue of treatment for the disease.
With a 5-year survival rate of less than 5%, pancreatic cancer is targeted by only a small number of promising drugs. But now, researchers have found that an acidic phospholipid known as phosphatidylserine (PS) may be a biomarker for pancreatic cancer as well as a therapeutic target of the disease. PS is abnormally exposed on the membrane surface of human pancreatic tumor cells, according to a research team led by Xiaoyang Qi, PhD, associate professor of hematology oncology at the University of Cincinnati Academic Health Center in Cincinnati, Ohio.
As Qi and colleagues described in PLOS ONE (2013;8:e75507), they used laboratory tests to correlate PS exposure and the cytotoxic effect of the lysosomal protein saposin C (SapC) in human pancreatic cancer cells. The investigators assembled SapC and the natural lipid dioleoylphosphatidylserine (DOPS) into nanovesicles, which selectively killed the cancer cells by inducing apoptosis (programmed cell death) while leaving noncancerous cells unaffected. The cytotoxic effect correlated with the surface exposure level of PS on the tumor cells; a distinguishing feature of SapC-DOPS is its ability to bind to PS.
Qi’s group also evaluated the effects of SapC-DOPS therapy in mouse models of human pancreatic cancer. Mice receiving this treatment showed clear survival benefits, and their tumors shrank or disappeared.