Investigation of the role of İFNγ signaling pathway in response to braf inhibitors in A375 and SK-MEL-1 human melanom cells

Malignant melanoma is associated with approximately 80% of skin cancer-related deaths, although it accounts for only 4% of all skin cancer types. In recent years, targeted therapies that directly inhibit BRAF protein such as Vemurafenib and Dabrafenib have been developed to combat molecular damage in the treatment of melanoma. Compared to conventional treatments, BRAF inhibitors have higher response rates, but undesirable conditions such as disease recurrence, short survival time and resistance to treatment are still the most important clinical problems in melanoma patients. To address this, there is a need to develop other small molecule inhibitor approaches, such as adjuvant therapy. Evidence that IFNγ not only controls tumor initiation and progression but also promotes the growth of tumor cells with immuno-invasive properties suggests that this cytokine may have a dual role. The aim of the thesis is to reveal the role of IFNγ signaling pathway in the response to BRAF inhibitors in human melanoma BRAF-mutant A375 and BRAF-mutant SK-MEL-1 cell lines with blocked IFNγ signaling pathway. MTT test was used to measure cell viability. IFNγ gene was blocked in a group of melanoma cells by administration of IFNγ siRNA. Whether IFNγ was successfully suppressed in melanoma cells after IFNγ siRNA applications was investigated by qRT-PCR. Cell viability decreased with increasing time and concentration in SK-MEL-1 and A375 melanoma cells treated with increasing concentrations of VEM and DAB for 24, 48, and 72 hours (*p<0.05). An increase in cell viability was observed in A375 and SK-MEL-1 human melanoma cells with IFNγ gene blocked by application of IFNγ siRNA compared to melanoma cells without IFNγ gene blocked, and resistance to BRAF inhibitors was detected. These results show that IFNγ induction should be performed as well as IFNγ inhibition in cells.