Expression of Survivin in Human Colorectal Cancer Tissues

ABSTRACT

Survivin, the recently discovered apoptosis inhibitor of inhibitor of apoptosis (IAP) family is located in chromosome 17q25. It is found only in fetal tissue and transformed tissue but is never found in normal adult tissue. Several authors reported survivin expression in various cancer tissues, which suggested the role of survivin in cancer development. This study intended to find the degree of survivin expression making use of RT-PCR technology and to compare the expression pattern of survivin, caspase 3, and PARP. METHODS: The cell lines known to have survivin expression such as HL60, Daudi, THP1, and colon cancer cell lines such as COLO 201, WiDr and breast cancer cell line ZR-75-1 were used for the positive control. For the negative control, normal colon tissues were included. The total RNAs from the frozen tissue of 6 normal colon, 36 specimens of colorectal cancer, and cell lines were used in RT-PCR. The 20 paraffin embedded tissues were used in immunohistochemical study in order to find out the degree of protein expression of caspase 3 and PARP. Western blotting was conducted on same tissues for caspase 3 as usual manners. RESULTS: The survivin expression by RT-PCR techniques was found in the 22 cases (61.1%). As a result of the immunohistochemical staining, 13 cases (65%) in caspase 3, 17 cases (85%) in PARP showed reduced staining. In western blotting, 32 kDa inactive form of caspase 3 was expressed in 16 cases (80%), but the band of active split form was not found. No significant relationship was found between survivin expression and clinicopathologic data of colorectal carcinomas, and expression of caspase 3 and PARP. CONCLUSIONS: These result suggest that apoptosis mechanism is depressed in colorectal cancer tissues and survivin plays a role in the inhibition of apoptosis of colorectal cancer. More profound study could confirm the apoptosis mechanism in tumorigenesis.