Abstract: Objective: To investigate the effect of epidermal growth factor receptor (EGFR) shRNA combined with rapamycin (RAPA) on the proliferation, migration and invasion of skin squamous cell carcinoma Colo-16 cells, and to explore its possible mechanism. Methods: Colo-16 cells were divided into five groups, normal cell group (Colo-16+phosphate buffer saline PBS), negative control group (Colo-16 cells+PBS transfected with shRNA-NC plasmid), EGFR shRNA group (Color-16 cells+PBS transfected with EGFR shRNA plasmid), RAPA group (conventionally cultured Colo-16 cells+RAPA), and combination group (Colo-16 cells+RAPA transfected with EGFR shRNA plasmid). Cell proliferation ability was measured by cell counting kit (CCK-8) and clone formation test. Scratch test and Transwell method were used to detect cell migration and invasion. The expression of Ki-67, MMP-2, MMP-9 protein and mRNA related to proliferation and invasion were detected by Western blot and RT-PCR . Single factor analysis of variance was used for comparison among multiple groups, and SNK-q test was used for multiple comparison between groups. Results: Colo-16 cell absorbance A value, cell clone formation rate, scratch healing rate, number of invasive cells, Ki-67, MMP-2, MM-P9 gene protein and mRNA expression in EGFR shRNA group, RAPA group and combination group were significantly lower than those in normal cell group and negative control group, with significant differences (Ps<0.05), and the combination effect was more obvious. There was no statistically significant difference between normal cell group and negative control group (Ps>0.05). Conclusion: EGFR shRNA combined with rapamycin has synergistic effect in inhibiting the proliferation, migration and invasion of Colo-16 cells, and its mechanism may be related to the double inhibition of EGFR/PI3K/AKT/mTOR signal pathway.

Key words: skin squamous cell carcinoma, epidermal growth factor, RNA interference, rapamycin, cell proliferation, cell migration, cell invasion