Effects of thymokinone and etoposide combination on cell viability in cervical cancer

Cervical cancer is the second most common type of cancer in women, after breast cancer, that causes the death of a woman every two minutes in the world. Major treatment options include surgery, radiotherapy, and chemotherapy. Etoposide, a topoisomerase-II inhibitor, is an effective chemotherapeutic agent in the treatment of lung cancer, testicular cancer, acute myelogenous leukemia and acute myelomonocytic leukemia, Hodgkin lymphoma and high-grade non-Hodgkin lymphoma, and cervical cancer. Research focuses on the discovery of innovative drug strategies to improve treatment outcomes. In alternative and complementary medicine, the positive effects of plants in cancer treatment have been the focus of attention and studies have begun to increase. In many studies, it has been suggested that thymoquinone, which is isolated from Nigella sativa species in the Ranunculacea family known as "çörek otu", has anticarcinogenic, cardioprotective, anti-inflammatory, analgesic, antioxidant, immune system strengthening effects. Studies on the efficacy of thymoquinone together with etoposide in cervical cancer are insufficient. In this study, it was aimed to evaluate the effect of combinations with thymoquinone on etoposide cytotoxicity in cervical cancer cell line (HeLa cell) by MTT method. Compared to the negative control, thymoquinone significantly decreased cell viability in a dose-dependent manner at the concentrations of 250 μM and above for 24 hours incubation and 125 μM and above for 48 hours incubation, and the IC50 value were 233.6 μM and 145.5 μM, respectively, in HeLa cells. The IC50 values of etoposide in HeLa cells were 167.3 μM and 52.7 μM at 24 and 48 hours of exposure, respectively. Thymoquinone significantly decreased the approximate IC50 value of etoposide in doses of 15.63 μM and above for 24 hours incubation and 31.5 μM and above for 48 hours incubation in a dose-dependent manner. Our results showed that thymoquinone can increase the cytotoxic effect of etoposide in cancer cell, which suggests that etopside may increase its anticancer effect, however comprehensive studies are needed on this subject. This study is a preliminary study and will contribute to the development of new treatment strategies.