Cytotoxicity and apoptosis of ovarian and breast cancer cell lines induced by OVS1 monoclonal antibody and paclitaxel.

OVS1 monoclonal antibody (MAb) produced against ovarian cancer is currently used to identify mucinous cystadenocarcinoma antigen as a tumor marker secreted in serum. The potential of OVS1 MAb in ovarian cancer treatment was studied by evaluating the induction of cytotoxicity and apoptosis of SKOV3 ovarian cancer and BT549 breast cancer cell lines induced by OVS1. Paclitaxel, an antitumor drug, was used as positive control and applied as a combined drug together with OVS1 MAb. OVS1 MAb and paclitaxel were found by MTT assay to induce cytotoxicity against both cell lines. The ED50 of OVS1 MAb were 26.25 and 25.00 microg/ml and of paclitaxel were 21.88 and 9.20 nM against SKOV3 and BT549 cell lines, respectively. The quantitative amount of cells determined by fluorimetric assay was correlated to the results of the MTT assay. The combined application of OVS1 MAb and paclitaxel on these two cell lines resulted in a greater cytotoxicity than observed by either agent alone. OVS1 MAb and paclitaxel applied against both cell lines induced the morphological changes of apoptotic cell death at 24 hours visualized by two color fluorescence dyes, Ho33342 and propidium iodide. Combination of the two substances enhanced the rate of apoptosis compared to either OVS1 MAb or paclitaxel given alone. DNA fragmentation was detected in an agarose gel electrophoresis after treating cells with OVS1 MAb and paclitaxel at 24 hours. These findings on the induction of cytotoxicity and apoptosis by OVS1 MAb on cancer cell lines have implications on the potential application of OVS1 MAb for clinical therapy.