Fibroblast Growth Factor 11 (FGF11) Promotes Non-small Cell Lung Cancer (NSCLC) Progression by Regulating Hypoxia Signaling Pathway

Abstract Background: Recently, accumulating studies highlight the critical regulatory roles of fibroblast growth factors (FGF), and a series of FGF, participated in the progression of multiple human cancers, including non-small cell lung cancer (NSCLC). Methods: Gene transcriptome analysis was used to identify the differential expression of FGF11 in NSCLC tumor tissues, GSE75037 and GSE81089 database analysis was performed on NSCLC tumor tissues and adjacent normal tissues to validate the expression of FGF11. Then, we selected 100 cases of NSCLC tumor tissues and 30 cases of matched adjacent normal tissues to confirm the mRNA and protein level of FGF11 by qRT-PCR and immunohistochemistry. Bioinformatics analysis and dual luciferase reporter analysis was also performed to examine the direct regulatory of FGF11 by miR-525-5p. CCK-8 and transwell assay was also performed to detect the cell proliferation, migration and invasion. Signal pathway analysis was also investigated the effect of FGF11 on NSCLC cell proliferation was associated with the hypoxia signaling pathway. The role of FGF11 in NSCLC tumor growth was further explored by in vivo study.Results: FGF11 was overexpressed in NSCLC tumor tissues and tumor cell lines, the high expression of FGF11 was closely associated with poor overall survival of NSCLC patients. In vitro loss- and gain- of function experiments demonstrated that FGF11 knockdown inhibited, whereas FGF11 overexpression promoted the proliferation, migration and invasion of NSCLC cells. The dual luciferase reporter assay confirmed that FGF11 was downregulated by miR-525-5p, and the effect of FGF11 on cell proliferation, migration and invasion could be interfered by miR-525-5p. We further found that FGF11 had significant correlation with hypoxia signaling pathway activation, meanwhile regulating HIF-1α. Further experiments implicated that the oncogenic role of FGF11 could be blocked via interfering of HIF-1α in NSCLC cells. Moreover, knockdown of FGF11 suppressed NSCLC tumor growth whereas overexpression of FGF11 promoted tumor growth in vivo. Conclusions: FGF11 might be functioned as an oncogene in tumor development, the findings of our study revealed a novel regulatory mechanism of FGF11 involved in hypoxia signaling pathway, which offers novel strategies for the treatment of NSCLC.