Inhibitory Effect of GnRH and Its Analog on Tongue Cancer Cells Might Be Related to Downregulation of GnRHR mRNA

Aim: We investigated the expression of type-I gonadotropin-releasing hormone receptor (GnRHR-I) in human tongue cancer SCC-25 cells and the effects of gonadotropin-releasing hormone (GnRH)-I and its analog triptorelin on SCC-25 cells and the related mechanisms of action. Methods: We used RT-PCR, realtime PCR (qPCR) and western blotting to detect the expression of GnRHR-I mRNA and protein in SCC-25 cells, We also used a Cell Counting Kit-8 (CCK-8) assay to calculate cell viability, after treatment with GnRH-I or triptorelin. Results: Results of agarose gel electrophoresis and DNA sequencing showed that the GnRHR-I mRNA of SCC-25 cells were amplified correctly. Western blotting showed that the protein samples of SCC-25 cells had a specific reaction at approximately 60 kDa. GnRH or triptorelin inhibited the proliferation of SCC-25 cells in a dose-dependent manner. GnRH-I and triptorelin at the same concentrations did not significantly differ in inhibiting the proliferation of SCC-25 cells (10 µg/ml: P=0.44,20 µg/ml: P=0.57, 40µg/ml: P=0.28,80 µg/ml: P=0.051). Results of qPCR showed that triptorelin treatment led to stronger inhibition of GnRHR-I mRNA expression in SCC-25 cells than did GnRH-I treatment. (P<0.05). Triptorelin also decreased GnRHR mRNA expression time-dependently. Conclusion: The SCC-25 cell line expresses GnRHR protein and mRNA. The inhibitory effect of GnRH-I and triptorelin on tongue cancer cells might be related to the downregulation of GnRHR-I mRNA.