2779

GNAT1

CSNBAD3|GBT1|GNATR;guanine nucleotide binding protein (G protein), alpha transducing activity polypeptide 1;GNAT1;guanine nucleotide binding protein (G protein), alpha transducing activity polypeptide 1

guanine nucleotide-binding protein G(T), alpha-1 subunit|guanine nucleotide-binding protein G(t) subunit alpha-1|rod-type transducin alpha subunit|transducin alpha-1 chain|transducin, rod-specific

3p21

protein-coding

Oral squamous cell carcinoma (OSCC) is the most common type of head and neck malignant tumor. however, its pathological mechanisms have not yet been elucidated. In the present study, we screened for candidate tumor-suppressor genes (TSGs) related to OSCC among 10 candidate genes located in 3p21.3, a region abundant with TSGs based on previous studies, using semi-quantitative reverse transcription PCR (RT-PCR). Three genes, GNAT1, SEMA3B and AXUD1, with low or no expression in OSCC tissues and the cell line TCA8113 were selected, and the promoter methylation status was further analyzed by methylation-specific PCR (MS-PCR). Hypermethylation in the promoter regions of SEMA3B was found in OSCC tissues, and a significant difference in the frequency of methylation of SEMA3B was observed between OSCC and non-cancerous tissues. Furthermore, TCA8113 cells treated with 5-Aza-Cdc started to re-express SEMA3B at a concentration of 5 microM or higher. Our study confirmed that three candidate TSGs with low expression may be involved in OSCC and that hypermethylation in promoter regions may contribute to the low expression of SEMA3B. These findings offer novel insights for clarifying the molecular mechanisms of tumorigenesis of OSCC as well as for aiding in its clinical diagnosis and therapeutic strategy.