Photodynamic therapy (
PDT) is a technique that can be used as a complementary
therapy in
cancer treatment combined with other therapeutic modalities.
Quercetin (QCT) is known to be effective in the treatment of
cancer, by reducing the cell viability of different
cancer cell lines. This study aimed to evaluate the influence of different concentrations of QCT in
PDT on the viability, mitochondrial membrane potential and induction of apoptosis/
necrosis in the human larynx
carcinoma cells (HEp-2). The HEp-2 cells were treated with
aluminum phthalocyanine tetrasulfonate (
AlPcS4) and QCT and subsequently irradiated with a
diode laser light (685 nm, 35 mW, 4.5 J/cm(2)). The results demonstrated that treatment of HEp-2 cells with high concentrations of QCT (at least 50 μM) reduced cell viability. This response was enhanced in cells subjected to
PDT supplemented with high concentrations of QCT. In addition, was observed decrease in the mitochondrial membrane potential and characteristics of late apoptosis and/or initial
necrosis process. QCT at concentrations from 50 μM improves
PDT-induced cytotoxicity by significantly reducing cell viability by apoptosis and/or
necrosis, and mitochondrial membrane potential of Hep-2 cells.