Photodynamic therapy potential of cobalt phthalocyanine in triple-negative breast cancer

Abstract

Triple-negative breast cancer (TNBC) has the worst prognosis among breast cancers. The deficiency of hormone receptors (ER-/PR-/HER-2-) limits treatment options. Photodynamic therapy (PDT) is a safe treatment method for target-specific applications and has no toxic side effects. In this study, the efficacy of PDT on TNBC cells after activation of phthalocyanine derivative CoPc-COOH with RED light was investigated. The cytotoxicity of CoPc-COOH in MDA-MB-231 cells was evaluated at 24, 48, and 72 h. To detect phototoxic activity, cells were exposed simultaneously to a dose range of CoPc-COOH at 48th hours and 20, 30, 40, and 50 J/cm2 RED light in a laser source with an output fluorescence of 12 mW/cm2. The apoptotic effect of single CoPc-COOH, RED light, and their combinations were examined by using the Annexin V method and the ROS generation potential using the carboxy-H2-DCFH-DA test in flow cytometry. DCF fluorescence intensity of control and dose groups were taken under the fluorescence microscope. The IC50 values of CoPc-COOH in MDA-MB-231 cells at the 24th, 48th, and 72nd hours were calculated as 131.04 µM, 66.75 µM, and 59.74 µM, respectively. In the phototoxicity test, 50 J/cm2 application increased the IC50 dose of CoPc-COOH to 73.73 µM; 20, 30, 40 J/cm2 application reduced the doses to 2.31 µM, 0.20 µM, and 28.14 µM, respectively. Compared to the untreated group, it was determined that ROS formation and apoptotic stimulation were triggered significantly in treatment groups. A combination of CoPc-COOH and 40 J/cm2 showed the highest synergistic effect.