Apoptotic effects of caffeic acid phenethyl ester on different colorectal cancer cell lines and alterations in the expression of survivin

Colorectal cancer is one of the most common cancer type. The resistance to chemotherapeutics which are used in the treatment of colorectal cancer constitutes an obstacle for the treatment of the disease. These chemotherapeutics also have toxic effects on healthy cells. In this thesis, it was aimed to investigate the apoptotic effects of caffeic acid phenethyl ester (CAPE) on different colorectal cancer cell lines and the alterations in the expression of anti apoptotic protein survivin. In this connection, it was analyzed the anti tumoral effects of CAPE on different colorectal cancer cell lines and healthy colorectal cancer line. Cell lines were treated with CAPE, a chemotherapeutic agent 5-fluorourasil (5-FU) and CAPE in combination with 5-FU. Their effects on different cell lines were invesitgated by cell viability tests. It was demonstrated that CAPE decreased cell viability of RKO, HCT-116 and DLD-1 cancer cell lines in a dose dependent manner. Morphological differences of cells after CAPE treatment were observed by acridine orange/ethidium bromide staining method. Apoptotic cell percentage and active caspase-3 alterations of the cells were observed by flow cytometric analysis. According to these analysis, CAPE increased apoptotic cell percentage and active caspase-3 level in RKO, HCT-116 and DLD-1 cell lines. The alterations of survivin, phospho p53-Ser46 and phospho p53-Ser15 protein levels were analyzed by western blot method. It was observed that CAPE caused different effects in survivin, phospho p53-Ser46 and phospho p53-Ser15 protein levels on different cell lines. The alterations of mRNA expression levels of survivin in different cell lines were analyzed by quantitative real time PCR method. It was shown that mRNA expression of survivin decreased in DLD-1 and RKO cell lines after CAPE treatment.