Current Advances in Anticancer Properties of Heptamethine Carbocyanine DZ-1 Conjugated to Artesunate: Generation of Reactive Oxygen Species

Heptamethine cyanine dyes and anticancer agents based conjugates are being developed for enhanced targeting and killing of cancer cells. DZ-1 dye conjugated agents induced cytotoxicity and mechanism of action have been shown in previous studies. In this study, a conjugated form of DZ-1 and artesunate (DZ-1-ART) was used to evaluate its cytotoxicity and elucidate the mechanism of actions in various cancer cell lines. Cells survival assays indicated dose-dependent cytotoxic activities of DZ-1-ART in HCT116, BxPC-3, and OVCAR-3 cell lines. Immunoblotting and terminal deoxynucleotidyl transferase dUTP nick-end labeling assay confirmed involvement of apoptosis in DZ-1-ART-induced cytotoxicity. To elucidate the anticancer mechanism of the action of DZ-1-ART, MitoTracker and JC-1 assay were used. The results showed that translocation of DZ-1-ART in the mitochondria was followed by disruption of mitochondrial outer membrane potential. Dichlorofluorescin diacetate assay confirmed the generation of reactive oxygen species (ROS) in DZ-1-ART treated cancer cells. An antioxidant, N-acetyl cysteine treatment with DZ-1-ART showed reduction in cell death as well as suppression of ROS generation. When compared to HCT116 wild-type cells, Bak and Bax-deficient HCT116 cells also showed similar levels of cytotoxicity of DZ-1-ART. Taken together, this study's results reported that DZ-1-ART could induce mitochondria-mediated, ROS-generated, and Bak and Bax-independent apoptosis in cancer cells.