ONCOLYTIC ACTIVITY OF HUMAN ORTHOPNEUMOVIRUS IN CANCER CELL LINES.

Abstract

This study was designed to elucidate the possible role of hOPV in the modulation of cell growth and apoptosis in cancer cell lines including human epidermoid carcinoma (HEp-2), lung epithelial cell line (A549), and breast cancer cell line (MCF-7). The oncolytic activity of hOPV on cancer cells was studiedin vitro. The virus titersweredeterminedbytissue culture infectious dose (TCID50/mL) in A549cell. The cytotoxic effect of the virus onHEp-2, A549, and MCF-7was determined using MTT and trypan blue dyeexclusion test assays. hOPV in the infected cells was detected using real-time reverse transcription polymerase chain reaction(rRT-PCR) and indirect immunofluorescence (IIF) assays. Therelative expression of apoptosis-related genes (CASP-3, -8, -9, Bax, Bcl-2, Bcl-XL, TP53, P21) during virus infection was estimated using rRT-PCR assay in comparison with the house-keeping gene (GAPDH). hOPV infection inhibited the growth of HEp-2, A549, and MCF-7cells in a dose-and time-dependent manner. At a multiplicity of infection (MOI) of 5, hOPV reduced the viability of A549cells to about 16%, HEp-2to 22%, and MCF-7to 28% (p = 0.001), while no significant inhibitory effect was observed when cells were infected at MOI of 1and 2. hOPV mRNA and antigens were detected in infected HEp-2, A549, and MCF-7cells by RT-PCR and IIF. Upon hOPV infection, expression of CASP-3, -8, -9, as well as Bax, TP53, and p21mRNA increased while expression of Bcl-2, Bcl-xL anti-apoptotic genes decreased. In hOPV-infected A549cells, the fold increase of CASP-8and CASP-9, Bax, TP53, and P21expression exceeded significantly compared to that in HEp-2or MCF-7cells. Ourresults provide evidence that hOPV could be a potential candidate for oncolytic virotherapy.