The investigation of the anti-cancer effect of photodynamic therapy using schiff base ligand complex as photosensitiser on human breast cancer MCF-7 cell line

Breast cancer is one of the most common causes of mortality among women in our present day. Photodynamic Therapy (PDT) with photoactive agents has become important recently because of the serious side effects of cisplatin used in the treatment of breast cancer. PDT is an alternative treatment that can show its effect with light, photosensitizer, and oxygen. The purpose of the present paper was to reveal the effect mechanism and possible antitumor activity as a result of 72-hour incubation by irradiating with LED light source at 15 J/cm2 after 3 different agents are applied to MCF-7 cells by comparing with cisplatin. Then, light-exposed groups (control, 25 μM cisplatin, 12.5 μM cisplatin, 25 μM complex-1, 12.5 μM complex-1, 50 μM complex-2 and 25 μM complex-2) and non-light-exposed groups (control, 25 μM cisplatin, 12.5 μM cisplatin, 25 μM complex-1, 12.5 μM complex-1, 50 μM complex-2 and 25 μM complex-2) were created. The highest level of cellular uptake of agents applied to MCF-7 cells was observed at the 12th hour, and the incubation period was determined as 12 hours. In all groups, Annexin V staining was performed for cell death, and immunofluorescence staining was performed with caspase-8 and caspase-9 for apoptosis. Also, the level of Reactive Oxygen Species (ROS) was evaluated with the DCFDA kit. It was determined with our MTT findings that cisplatin, complex-1, and complex-2-mediated PDT increased cytotoxicity significantly. The level of ROS differed significantly between the non-light-exposed and light-exposed groups. Apoptotic and necrotic cell death was detected with caspase-8 and caspase-9 immunofluorescent staining after cisplatin and complex-1-mediated PDT. Immunofluorescent staining with caspase-8 and cell death were not observed after complex-2-mediated PDT. Also, a low level of caspase-9 fluorescent staining was detected in complex-2-mediated PDT. In conclusion, complex-1-mediated PDT was found to have a potential anticancer effect in MCF-7 cells. However, complex-2-mediated PDT alone did not have a curative effect.