Objective: To investigate the expression of Transient Receptor Potential Melastatin type 2 (TRPM2) in the human tongue squamous cell carcinoma tissues and SCC cell lines. The effect of activated and down-regulation of TRPM2 on SCC cell lines were observed.

Methods: Immunohistochemical staining, Western-blot and Real-time PCR were used to survey the expression of TRPM2 in the human tongue squamous carcinoma tissues, SCC cell lines and non-malignant tongue tissues; MTT assay, trypan blue staining assay and flow cytometry techniques were used to detect the effect of exogenous H ₂ O ₂ on the proliferation, apoptosis and cell viability of SCC cell lines, respectively; Western-blot, Real-time PCR and flow cytometry techniques were used to study the altered expression of TRPM2, tumor related protein and cell apoptosis rate in SCC cell lines after treated by shRNA technique.

Results: The positive expression of TRPM2 was observed in human tongue squamous carcinoma tissues and SCC cell lines, while which was negative in non-malignant tongue tissues. The proliferation and cell viability of SCC cell lines were significantly inhibited by different concentrations of H ₂ O ₂ ( p < 0.05), while apoptosis rate was notably increased by which. Western-blot showed that expression of the tumor and apoptosis related protein including p53, p21, pro-caspase3, pro-caspase9 and bcl-2 reduced in SCC cell lines by exogenous H ₂ O ₂ . After treated by shRNA technique,the expression of TRPM2 and p53 reduced in SCC cell lines, while the expression of p21 increased,and the apoptosis rate of SCC cell lines significantly increased ( p < 0.05).

Conclusion: The high expression of TRPM2 in human carcinoma of tongue specimens and SCC cell lines indicated that the progression of tumor may have something to do with its abnormal expression. Our data showed that ionophorous proteins may play an importmant part in the process of the tumour generation and demonstrated a possible downstream mechanism which TRPM2 may involved in. We can conclude that TRPM2 may play an important role of dual regulation in progression of tumor and it may provide a new way for tumor gene-targeted therapy.