LAGE3 promotes cell metastasis and stemness in non-small cell lung cancer companied with AKT/PI3K signaling pathway activation

Abstract

Background: Non-small cell lung cancer (NSCLC) is reported to have high mortality and morbidity rate worldwide. It is highly susceptible to metastasis. Previous reports have shown the L antigen family member 3 (LAGE3) expression in many cancers and has a carcinogenic role. However, the molecular mechanism of LAGE3 in NSCLC needs to be further explored.

Methods: LAGE3 expression profile of NSCLC patients and normal samples in the TCGA cohort was utilized for visualization. Expression pattern of LAGE3 in cell lines of NSCLCs were determined through qRT-PCR. Further, transfection experiments was conducted to measure the LAGE3's effect on the migration, proliferation, invasion, and stemness in NSCLC cell lines (A549 and H1975) by the assays of CCK-8, colony formation, EdU, transwell, and flow cytometry. The in vivo xenograft tumor growth in the nude mouse was conducted to confirm LAGE3 effect on NSCLC tumor growth. Furthermore, western blotting was applied to determine the levels of core proteins including AKT/PI3K signaling pathway and stemness proteins of Nanog, OCT4 and SOX2.

Results: The TCGA based computational analysis showed that LAGE3 mRNA level in NSCLC was inter-related to worse overall survival. The up-regulated level of LAGE3 in NSCLC cell lines indicated its possibility as a future diagnostic and prognostic biomarker. Functional assays showed that cell migration, proliferation, invasion, sphere formation, and stemness-related protein (Nanog, SOX2, and OCT4) levels were significantly repressed by the knockdown of LAGE3. Subsequently, inhibition of LAGE3 in nude mice (in vivo) demonstrated its ability to reduce the tumor growth of NSCLC. The study also showed that LAGE3 knockdown suppressed cell progression by inactivating the signaling pathway of AKT/PI3K.

Conclusions: LAGE3 could promote NSCLC development by activating the AKT/PI3K signaling pathway, thereby accelerating metastasis and cell stemness.

Keywords: AKT/PI3K; Cell proliferation; LAGE3; Migration and invasion; NSCLC; Stemness.