Proapoptotic activity induced by photodynamic reaction with novel cyanine dyes in caspase-3-deficient human breast adenocarcinoma cell lines (MCF/WT and MCF/DX).

Photodynamic therapy (PDT) is currently one of the cancer treatment options. PDT requires the application of a photosensitizer (such as: porphyrins, chlorines, and phthalocyanines) that selectively targets malignant cells. It is a dilemma to find a proper photosensitizer. In our study, we have tested a new in-vitro group of cyanine dyes. These dyes are widely applied in biotechnology as fluorescent markers. Two malignant adenocarcinoma cell lines (MCF-7/WT and MCF-7/DOX) were investigated using photodynamic reaction (PDR) with four cyanine dyes (KF-570, HM-118, FBF-749, and ER-139). KF-570 and HM-118 were irradiated with red light (630 nm), whereas FBF-749 and ER-139 with green light (435 nm). To evaluate PDR efficiency, a clonogenic test was conducted. Apoptosis was investigated by TUNEL and NCA (neutral comet) assays. Proteins selected as indicators of the apoptotic pathway (AIF, sPLA2, Smac/Diablo) and intracellular response markers (SOD-1 and GST-pi) were detected using western blot. The highest number of apoptotic cells (ca. 100%) was observed after PDR with HM-118 and KF-570 in both conducted tests, in both cell lines. The results showed that HM-118 and KF-570 cyanine dyes demonstrated a major phototoxic effect causing apoptosis in doxorubicin-resistant and sensitive cell lines.