Effect of Ad-p16 combined with CDDP or As2O3 on human bladder cancer cells

To evaluate the therapeutic efficiency of combined use of p16-expressing adenovirus and chemotherapeutic agents CDDP or As2O3 on human bladder cancer cell line EJ, the human bladder cancer cell line EJ were transfected with adenovirus-mediated p16 gene (Ad-p16), with administration of cisplatin (CDDP) or arsenic trioxide (As2O3). The cell growth, morphological changes, cell cycle, apoptosis and molecular changes were measured using cell counting, reverse microscopy, flow cytometry, cloning formation, immunocytochemical assays and in vivo therapy experiments to evaluate the therapeutic efficacy of such combined regimen. Ad-p16 transfer and CDDP or As2O3 administration to EJ cells could exert substantially stronger therapeutic effects than the single agent treatment. Especially in in vivo experiments, combined administration of p16 and CDDP or As2O3 induced almost tumor diminish compared to the partial tumor diminish induced by single agent. Moreover, delivery of Ad-p16, or administration of minimal-dose CDDP or As2O3 or combined regimen could induce massive apoptosis of EJ cell. Cell cycle analysis demonstrated that administration of CDDP or As2O3 remarkably arrested EJ cell in G1 prior to apoptotic cell death. When treated with combined regimen, cells were arrested in G1 to a greater extent prior to apoptotic cell death. It is concluded that after introduction into EJ cell, Ad-p16 shows enhanced therapeutic efficacy for EJ cell when used in combination with CDDP or As2O3.