Investigating Key Enzymes Involved In Glypican-3 Release from Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world. This form of cancer has a high rate of metastasis and recurrence, with only 10-20% of primary tumors in patients are resectable at the time of diagnosis. Uniquely, HCC contains unusually high amounts of glypican-3 (GPC3). GPC3 is a member of the glypican family, which are a family of heparan sulfate proteoglycans (HSPGs) anchored to the cell surface by a glycosylphosphatidylinositol (GPI) linkage. In general, glypicans act as coreceptors and interact with growth factors to regulate cellular growth. GPC3 is known to heavily promote cancer progression and tumor angiogenesis in HCC patients. GPC3 shed from the cell membrane becomes soluble and can freely interact with other cells. Elevated levels of soluble GPC3 were frequently found in the extracellular microenvironment of HCC cells, and higher levels of soluble GPC3 are directly associated with poorer prognosis of HCC. In this project, enzyme-linked immunosorbent assays (ELISA) and western blots were used to determine and compare the amount of GPC3 shedding that occurred under different conditions. The purpose of this project is to identify key enzymes involved in GPC3 shedding from the HCC cell surface. Higher additions of specific enzymes to HCC cells induced higher concentrations of soluble GPC3 from the cell surface, demonstrating a direct correlation between additions and GPC3 shedding. This demonstrates HCC’s dependence on enzymes for HCC tumor progression and angiogenesis, and can open the way to the creation of drugs that selectively target molecules HCC depends on with minimal adverse effects to the patient