Evaluation of Cytotoxic Effects of a DinuclearPalladacycle Derivative, Biphosphinic Complex, on Cisplatin-Resistant HT- 29 Cells

Previous studies showed that palladacycle complexes with three phenyl phosphine ligands and piperidine or biphosphinic based palladacycle complexes were cytotoxic on K562, HT29, and Hela cell lines. In the present study, in order to evaluate the efficacy of the compound on cisplatin resistant cells, first we made HT-29 cells resistant to cisplatin, and then evaluated the potential cytotoxicity of the mentioned plladacylce complex on them. In addition, it was evaluated whether cytotoxic effect of the compound is mediated via apoptosis or necrosis death mechanisms. In this regard, Annexin V/PI by staining followed by flow cytometric analysis was performed. Results showed that palladacycle complexes were 45 times more cytotoxic than cisplatin (P<0.05) on the resistant HT-29 cells. Flow cytometry results also revealed that apoptosis induction was the major cell death mechanism of these compounds. Therefore, it could be concluded that these compounds might be effectively cytotoxic for cisplatin resistant cells. However, further in vitro and in vivo preclinical studies on evaluation of specific and non-specific cytotoxic characteristics of these complexes are necessary.