The effects of cetuximab on apoptotic and autophagic genes in metastatic colorectal cancer cells

Purpose: The colorectal cancer (CRC) is one of the most common cancer type and chemotherapy has an important effect in the treatment. Recently, a number of studies investigating the effect of chemotherapeutic agents on genes involved in apoptosis and autophagy have been carried out. In this thesis, it was aimed to investigate the apoptotic, autophagic and cytotoxic effects of cetuximab (CTX), used for the treatment of colorectal cancer and is a monoclonal antibody that is epidermal growth factor (EGF) antagonist, on the cancer cells. Material and Method: Cetuximab was administered to colorectal cancer cell lines at different doses to form 10 test groups and all groups were left in incubations for 24 and 48 hours. MTT assay was applied for determine the cytotoxicity. TUNEL assay was used to detect the apoptosis by histochemical. p21, p27, p57, KRAS, LC3A, BECN1, EGF and ATG4A gene expression levels were measured by Real-Time PCR. Findings: MTT cytotoxicity analysis indicated that 10 μg/mL cetuximab was the effective dose. At the same time, there was a decrease in KRAS and EGF gene expression while p21, p27, p57, LC3A, BECN1 and ATG4A gene expressions were increased. In TUNEL staining, an increase in apoptosis was observed with increasing dose of cetuximab. Result: We can come to the conclusion that CTX mediates HT-29 KRK cells to apoptosis and autophagy by increasing both p21, p27, p57 gene expressions and ATG4A, LC3A and BECNI gene expressions. In addition, it can be said that inhibiting the growth of cancer cells by decreasing EGF and KRAS gene expression.