The biological functions of LGR5 in promoting non-small cell lung cancer progression

BACKGROUND: The Leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), which is used as a marker of adult stem cells and colorectal cancer stem cells (CSCs), is closely associated with the progression of non-small cell lung cancer (NSCLC). This study aimed to identify the clinical significance and biological function of LGR5 in NSCLC. METHODS: Quantitative reverse transcription polymerase chain reaction (RT-PCR) was applied to detect the expression of LGR5 and stemness-related genes in 22 NSCLC patients, and the clinical significance of LGR5 in NSCLC progression was estimated by statistical analysis. LGR5 overexpressing A549- and H1299-transfected cells were established, and CCK-8 and clone formation assays were used to test the proliferation ability. A wound-healing assay was utilized to clarify the migration ability. The invasion ability was confirmed via the Transwell assay kit. RESULTS: LGR5 expression was markedly higher in NSCLC tissues than in the matched adjacent normal tissues, and had a trend to associate with tumor size, lymph node metastasis, and TNM stage. The proliferation rates, clone formation rates, wound healing rates, number of invasive cells, and the NOTCH1 expression of the LGR5 overexpressing groups, were significantly higher than those of the control groups. CONCLUSIONS: LGR5 plays an essential role in NSCLC tumorigenesis and is closely associated with the proliferation, metastasis, and invasion of NSCLC cells. LGR5 may promote NSCLC progression via NOTCH1 and could be a new target for gene-targeted therapies for NSCLC.