Down-regulation of γ-synuclein in human esophageal squamous cell carcinoma

AIM: To investigate gene expression pattern of human gamma-synuclein gene in human esophageal squamous cell carcinoma (ESCC) by using semi-quantitive reverse transcription polymerase chain reaction (RT-PCR), and to study the role of gamma-synuclein in the development of human ESCC. METHODS: Semi-quantitive RT-PCR of 27 pairs of specimens of human ESCC tissues and corresponding normal tissues was used to investigate the expression pattern of gamma-synuclein in ESCC. 9706/gamma-syn cells in which gamma-synuclein was overexpressed were obtained through cloning gamma-synuclein gene by PCR and transfecting it into ESCC 9706 cells, then selecting with G-418 for 14 days. The biological effects of gamma-synuclein were measured and compared between 9706/gamma-syn and 9706/vec cells by cell growth curve and soft agar assay. RESULTS: RT-PCR showed that gamma-synuclein gene was expressed in all the 27 cases of normal epithelial tissues, while downregulation of gamma-synuclein was observed in 16 out of the 27 cases (59.3 %) of ESCC. There were also 6 cases of ESCC tissues with a high expression level of gamma-synuclein mRNA. In functional analysis we found that over-expression of gamma-synuclein in ESCC 9706 cells could inhibit the growth rate and transformation ability of ESCC 9706 cells. CONCLUSION: The low expression level of gamma-synuclein in human ESCC and the biological effects of gamma-synuclein over-expression on ESCC 9706 cells suggest that gamma-synuclein may play a role as a negative regulator in the development of human ESCC.