Cytotoxic and Apoptosis-Inducing Activities of Iridium Complexes Bearing 2-Phenylimidazo[4,5-f][1,10]-Phenanthroline Derivatives in Human Cancer Cells

Abstract

In recent years, there has been growing exploration of organometallic transition metal complexes as promising options for developing anticancer agents that offer the potential of reduced toxicity compared with the commonly utilized cisplatin analogs. In this respect, iridium complexes containing 2-phenylimidazo- [4,5-f][1,10]-phenanthroline derivatives with different substituents were investigated in different cell lines as potential anticancer agents. All the compounds exhibited potent cytotoxic activity against Caco-2, HeLa, A549, and MDA-MB-231 cell lines. EC₅₀ values of compound 1 were found to be 6.44 μM for Caco-2, 24.78 μM for HeLa, 9.14 μM for A549, and 4.45 μM for the MDA-MB-231 cell line. Similarly, EC₅₀ of 3 was found at 15.07, 14.15, 10.33, and 4.48 μM respectively. The EC₅₀ value of 2 was found to be 12.71 μM for Caco-2, 24.31 μM for HeLa, and 7.44 μM for MDA-MB-231 cells. EC₅₀ values of compound 4 were found to be 28.20 μM for Caco-2, 12.79 μM for HeLa, 8.33 μM for A549, and 3.76 μM for the MDA-MB-231 cell line. The results of gene expression and flow-cytometry analysis showed that the compounds caused the induction of apoptosis in all cancer cell lines by changing caspase 3, Bcl-2, and Bax proteins. The obtained results demonstrate that compounds could be introduced as potent agents to prevent the progression of certain types of cancer. However, preclinical and clinical trials will be needed to evaluate these complexes to obtain safe, effective, and optimal therapeutic drugs for cancer patients.