Induced cell death pathway post photodynamic therapy using a metallophthalocyanine photosensitizer in breast cancer cells

Objective: Zinc phthalocyanine (ZnPcS_mix) was used as the photosensitizer (PS) in this study to investigate the cell death patterns as a result of photodynamic therapy (PDT) in a breast cancer cell line (MCF-7) in vitro using a 680 nm diode laser at a fluence of 5 J/cm². Background: PDT is a noninvasive form of cancer therapy, successfully applied for the treatment of various cancer types. Methods: Flow cytometry using Annexin V-fluorescein isothiocyanate (FITC), a cell death immunosorbent assay (ELISA), and gene expression analysis following ZnPcS_mix mediated PDT were performed to determine the induced cell death pathways. Results: The apoptotic cells abounded after the treatment, nuclear fragmentation was seen as oligonucleosomal degradation and increased expression of the B-cell lymphoma 2 (Bcl-2), DNA fragmentation factor alpha (DFFA1), and caspase 2 (CASP2) genes, indicated that apoptosis is the main induced mode of cell death. Conclusions: ZnPcS_mix mediated PDT led to an apoptotic cell death pathway and the PS used showed its ability to stimulate and initiate programmed cell death.