Investigation in cell culture of the effect of adding wheat germ aglutin (WGA) to cisplatin treatment in melanoma on biochemical mechanisms and drug

Objective: Melanoma is the most aggressive skin cancer, accounting for only 1,7% of all skin tumours. Despite limited toxicity to normal tissues, WGA has been shown to be toxic at low doses to pancreatic, liver, bone (osteosarcoma) and skin (melanoma) cancer. Cisplatin is a chemotherapeutic agent known for its ability to induce DNA damage and apoptosis, but is not very effective in the treatment of melanoma. The development of new combinations that can sensitise melanoma cells to Cisplatin is one way to increase drug efficacy. The aim of this study was to evaluate the effects of single and combined doses of Cisplatin and WGA on oxidative stress, apoptosis and drug resistance in melanoma cells in vitro. Materials and Methods: In our study, after the IC50 doses of Cisplatin and WGA were found by MTT test in G361 melanoma cell line, 4 study groups (Control, WGA, CP, WGA+CP) were formed and 24 hours of treatment was performed at these doses. The effect of single and combined doses on oxidative process was analysed by measuring TAS and TOS levels and calculating OSI. Bax, Bcl-2, Sit-c, Casp-3 and Casp-9 were analysed by ELISA, Western Blot and RT-qPCR for apoptosis; ABCB1, ABCC1 and ABCG2 were analysed by RT-qPCR for drug resistance. Results: WGA was found to induce oxidative stress by increasing TOS and OSI values and decreasing TAS values compared to the control group. CP alone and in combination with WGA decreased TAS, TOS and OSI values compared to the control group. WGA and WGA+CP groups increased Bax, Bcl-2 and Cyt-c levels evaluated by ELISA analysis compared to the control group, and the calculated apoptotic index value was found to be highest in the WGA+CP group. The mRNA expressions of ABCC1, one of the drug resistance-related genes, in the Cisplatin-treated group, ABCG2 in the WGA-treated group and their combinations significantly increased ABCB1 and ABCC1 mRNA expressions. Conclusion: The findings support the antiproliferative and apoptotic activity of WGA alone and in combination with Cisplatin in melanoma. The high apoptotic index provided by WGA-Cisplatin combination suggests that this treatment modality may be an important option. On the other hand, this study may be a guide for new studies to be conducted to increase cytotoxicity and reduce side effects in Cisplatin chemotherapy. Keywords: Apoptosis, Melanoma, Cisplatin, WGA.