The value of basal expression level of hemoxygenase-1 for sensitivity of human melanoma cells to oxidative stress in vitro

Introduction.The molecular basis of radio- and photodynamic therapy (PDT), the mechanism of action of a number of antitumor chemotherapy drugs is oxidative stress (OS). The enzyme hemoxygenase-I (НO-1), a molecular marker of OS, is a key participant in the system of protection and adaptation of tumor cells under stress.Objective.To find out whether the sensitivity of human melanoma tumor cells to OS depends on the basal and modulator-induced levels of НO-1 expressionMaterial and methods.Human melanoma cell lines were used in the study. The expression of mRNA НO-1 in cells was studied by real-time RT-PCR, the reactive oxygen species content in cells – by flow cytometry and the cytotoxicity of drugs – by MTT assay.Results.According to our data, human melanoma cells have different basal levels of HO-1 transcription: high (3.0–3.5 o. u.) in lines MelIL, MelP, medium (1.5 o. u.) in lines MeWo, MelZ, MelIbr and low (0.5 o. e.) – MelMe, A375).There is no direct correlation between the level of basal cell expression of HO-1 and their sensitivity to the OS inducer – Н2О2. The hemin-induced increase in HO-1 expression in cells is accompanied by doubled resistance to Н2О2. It was found that HO-1 repression in the presence of apigenin was registered in melanoma cells with different basal levels, but sensitization to Н2О2 (2–4 times) was observed only for cells with medium (MeWo) and low (A375) levels of basal HO-1 expression. It was found that the decrease in basal expression of HO-1 induced by apigenin is accompanied by an increase in the reactive oxygen species content in cells.Conclusions.The results of our research allow us to recommend natural flavon apigenin, a modulator of HO-1 expression, for inclusion in the chemotherapy and PDT regimens to increase the effectiveness of human melanoma treatment.