Abstract:

Objective To study the expression of the receptor for activated protein C kinase 1(RACK1, GNB2L1) in gastric cancer cells HGC27 and the effect of overexpressed RACK1 on the growth of HGC27 cells. Methods The gastric carcinoma cells HGC27 and normal gastric mucosa GES-1 cells were cultured in vitro and collected 48hours later. RNA and protein were extracted from the cells. The expression of RACK1 mRNA and protein was detected by RT-PCR and Western blotting in HGC27 and GES-1 cells, respectively. The recombinant plasmid pcDNA3.1A-flag-RACK1 was constructed using human embryo kidney cell HEK293 cDNA as template and transfected into HGC27 cells with Lipo2000, and the transfection efficiency was evaluated by Western blotting and the survival rate of HGC27 cells was detected by MTT method . Results The expressions of RACK1 mRNA and protein in HGC27 cells were lower than that in GES-1 cells (P<0.01). Double enzyme digestion analysis and sequencing analysis showed that the recombinant plasmid of pcDNA3.1A-flag-RACK1 was successfully constructed. There was no significant difference between untransfected group and pcDNA3.1 vector group（P>0.05）, while the RACK1 protein expression was significantly increased compared with untransfected group and vector transfected group(P<0.01). The survival rate of cells transfected with pcDNA3.1A-flag-RACK1 at 72 hours and 96 hours was significantly less than that of cells with pcDNA3.1 transfection (P<0.01). Conclusion The expression level of mRNA and protein of scaffold protein RACK1 in HGC27 gastric carcinoma cells is downregulated. Overexpressed RACK1 can significantly inhibit the growth of HGC27 cells. This study provides a new theoretical and experimental basis for RACK1 as a new molecular marker and star molecule in signaling pathways.

Key words: Receptor for activated C kinase 1, Gastric cancer cell, Proliferation, HGC27 cell, Western blotting