LRIG1 regulates proliferation and invasion of tongue squamous cell carcinoma via EGFR pathway

Tongue squamous cell carcinoma (TSCC) is an aggressive neoplasm which typically spreads through invasive growth with serious morbidity and mortality. Previous studies suggested that the expression of LRIG1 functions as the vital suppressor gene in various human cancer types by inhibiting invasion and proliferation. However, little is known about the downstream genes coordinating this process in tongue squamous cell carcinoma. In this study, we overexpressed LRIG1 with a full-length expression vector and used small interfering RNA (siRNA) to block LRIG1 gene in the Tca8113 TSCC cell line. The expression of LRIG1 and EGFR at mRNA and protein level were tested by qRT-PCR and Western blot, respectively. The transwell assay and CCK8 assay were performed to detect the invasion and proliferation of TSCC cells. LRIG1 overexpression reduced EGFR expression, and significantly inhibited the invasion and proliferation of TSCC cells. In addition, silence of endogenous LRIG1 expression resulted in elevated EGFR expression and increased cell invasion and proliferation. Our result suggested that LRIG1 restricted TSCC invasion and proliferation via regulating the EGFR pathway. Restoration of LRIG1 in TSCC cells could be used as a novel therapeutic strategy.