Abstract:

Objective To investigate the effect and mechanism of glucose regulated protein78 (GRP78) on the proliferation and metastasis of tongue squamous cell carcinoma(TSCC) treated with cisplatin. Methods MTT assay was used to detect the proliferation of CAL27 and CAL27DR cell. RNA interference was used to knockdown GRP78 expression in CAL27DR cells and then cells were treated with DDP(0 μmol/L, 2.5 μmol/L, 5.0 μmol/L and 10.0 μmol/L)and the proliferation ability was detected by EdU. Transwell assay was used to detect the invasive potential and scratch assay was used to detect the migration potential in CAL27DR and siGRP78 cells. Immunofluorescence assay was used to detect the expression of Cortactin. Western blot assay was used to detect the protein expression of ERK, p-ERK, AKT, p-AKT, FAK, p-FAK, N-cad and E-cad in CAL27DR and siGRP78 cells. Results MTT result showed that the proliferation potential was increased obviously in CAL27DR cells compared with CAL27 cells. EdU assay result showed that the proliferation potential was decreased obviously in siGRP78 cells compared with vector (P<0.05).Transwell and scratch assay results showed that the invasive and migration potential was also decreased in siGRP78 cells compared with vector (P<0.05). Immunofluorescence assay result showed that Cortactin protein expression was decreased in siGRP78 cells compared with vector. The phosphorylation levels of ERK, AKT and FAK were significantly increased in siGRP78 cells compared with vector (P<0.05). The protein expression of N-cad was increased in siGRP78 cells compared with vector and the protein expression of N-cad has the opposite trend (P<0.05). Conclusion GRP78 up-regulates cell proliferation through ERK and AKT kinases, resulting in decreased sensitivity of cells to DDP, and mediates the occurrence of EMT and promotes cell invasion and metastasis by activating FAK kinase in tongue squamous cells.

Key words: GRP78, tongue squamous cell carcinoma, cisplatin, metastasis