Expression of γ-synuclein in colorectal cancer tissues and its role on colorectal cancer cell line HCT116

AIM: To investigate the expression pattern of gamma-synuclein in colorectal cancer (CRC) tissues, and to study the effects of gamma-synuclein on CRC cell line HCT116 biological features in vitro. METHODS: The expression pattern of gamma-synuclein was determined in 54 CRC tissues and 30 tumor-matched nonneoplastic adjacent tissues (NNAT) 5 cm away from the tumor via real-time quantitative reverse transcription PCR (RT-PCR) and immunohistochemistry. The relationship between gamma-synuclein protein expression and clinicopathological factors of CRC tissues was analyzed. Three small interfering RNA (siRNA) targeting gamma-synuclein mRNA plasmids were constructed and transfected into the CRC cell line HCT116. The stable cell lines were selected with G-418 for 28 cl, and the biological features of these cells were examined by cell growth curve, soft agar assay, and cell migration and invasion assays in vitro. RESULTS: The expression of gamma-synuclein mRNA and protein was much higher in CRC tissue samples than in NNAT samples (P = 0.02, P = 0.036). There was a significant correlation between the gamma-synuclein protein expression and clinical stage and lymph node involvement of CRC (P = 0.02, P = 0.033). In functional analysis we found that down-regulation of gamma-synuclein expression in HCT116 cells could inhibit the growth, colony formation rate, and migration and invasion ability of HCT116 cells. CONCLUSION: Increased expression of gamma-synuclein in CRC tissues and the biological effects of reduced gamma-synuclein expression on HCT116 cells suggest that gamma-synuclein may play a positive role in the progression of CRC. (C) 2009 The WJG Press and Baishicleng. All rights reserved.