Enhancement of the Adenoviral Sensitivity of Human Ovarian Cancer Cells by Transient Expression of Coxsackievirus and Adenovirus Receptor (CAR)

Abstract Objective. The coxsackievirus and adenovirus receptor (CAR) is known to be a primary receptor for attachment during adenovirus infection of target cells and thus is closely related to adenoviral infection efficiency. To extend this notion to human ovarian cancer, we investigated the difference in expression levels of CAR in human ovarian cancer cell lines and whether their adenoviral sensitivities are enhanced by transient transfection of the CAR gene. Methods. Adenoviral infection efficiency was examined by flow cytometry analysis, β-galactosidase staining, and β-galactosidase activity assay. Expression of the CAR-specific mRNA and protein was analyzed by reverse transcription polymerase chain reaction and flow cytometry, respectively. Results. Expression of CAR in human ovarian cancer cell lines (SKOV3, 2774, PA-1, and OVCAR3) appeared to be correlated with their susceptibilities to adenovirus-mediated gene delivery. The 2774 and PA-1 cells expressing an easily detectable level of CAR on the cell surface showed a higher susceptibility to infection with both AdCMVGFP and AdRSVβgal than SKOV3 and OVCAR3 cells, both of which had hardly detectable levels of CAR. Ectopic expression of the CAR gene by transient transfection of these ovarian cancer cells resulted in a dramatic increase in their adenoviral sensitivities. Conclusion. These data show that the expression of CAR is closely related to susceptibility to adenovirus infection in human ovarian cancer cells. These results indicate that the CAR gene can be a useful tool in boosting the efficiency of adenoviral vector-mediated gene therapy against human ovarian cancer.