Disruption of p97/VCP induces autophagosome accumulation, cell cycle arrest and apoptosis in human choriocarcinoma cells

Gestational choriocarcinoma is aggressive trophoblastic disease. The development, progression and the cure of this disease is not well-established. p97/Valosin containing protein has been shown to play critical roles in many cellular processes. In various cancers, higher expression of p97/VCP has been reported and targeting of p97/VCP with its spesific inhibitors or siRNA's (siVCP) in cancer therapy was suggested. However, no study is avaible about the expression and function of p97/VCP in gestational choriocarcinoma. Hence, the aim of the study was to evaluate effects of p97/VCP inhibitor, DBeQ and siVCP on choriocarcinoma cells. We use human placental choriocarcinoma cell line (Jeg3) as model to find out the effects of DBeQ and VCP siRNA's (siVCP) on apoptotic and autophagic pathway by immunflouroscence staining, Western blotting, qPCR and flow-cytometry. p97/VCP siRNA's and DBeQ induced accumulation of autophagic proteins, LC3II and p62 in the cytoplasm of Jeg3 cells detected. Concurrently, Jeg3 cells treated with DBeQ and siVCP demonstrated G0/G1 cell cycle arrest, accompanied by accumulation of poly-ubiquitinated proteins. Moreover, disruption of p97/VCP by siRNA and DBeQ inhibited cancer cell growth managing the caspases-3 and -7. Our results show that inhibition of p97/VCP activity with DBeQ and depletion of p97/VCP expression with siRNA in Jeg3 cells induce caspase activation, inhibits cell proliferation and leads to a defect in autophagosome maturation, thus providing potential target for the prevention and treatment of choriocarcinoma.