Nicotine upregulates FGFR3 and RB1 expression and promotes non-small cell lung cancer cell proliferation and epithelial-to-mesenchymal transition via downregulation of miR-99b and miR-192

Biomed Pharmacother. 2018 May:101:656-662. doi: 10.1016/j.biopha.2018.02.113. Epub 2018 Mar 22.

Abstract

Background: Tobacco smoke is by far the greatest risk factor for non-small-cell lung cancer (NSCLC). Nicotine, an active alkaloid in tobacco, is unable to initiate tumorigenesis in humans and rodents, but can promote the growth and metastasis of various tumors, including NSCLC, initiated by tobacco carcinogens. Recently, cigarette smoke is reported to downregulate 24 miRNAs more than 3-fold in the lungs of rats, and most of these downregulated miRNAs are associated with NSCLC initiation and development. Nicotine as the major tobacco component might be associated with the expression changes of some miRNAs.

Methods: qRT-PCR was performed to determine the miRNA and mRNA expression, and western blot was conducted to measure protein expression. MTT assay was used to detect cell proliferation.

Results: The effects of nicotine on the expression of 24 miRNAs in NSCLC cell lines were determined, and the results showed that nicotine treatment decreased miR-99b and miR-192 expression. Cell proliferation and epithelial-to-mesenchymal transition (EMT) detection showed that nicotine promoted NSCLC cell proliferation and EMT, and restoration of miR-99b or miR-192 expression relieved the effects of nicotine on NSCLC cell proliferation and EMT. Subsequently, fibroblast growth factor receptor 3 (FGFR3) and retinoblastoma 1 (RB1) were confirmed to be the targets of miR-99b and miR-192, respectively, and were upregulated by nicotine in NSCLC cells. In addition, FGFR3 or RB1 knockdown inhibited NSCLC cell proliferation and EMT.

Conclusion: This study, for the first time, elucidates nicotine-miR-99b/miR-192-FGFR3/RB1 regulatory network that nicotine promotes NSCLC cell proliferation and EMT by downregulating miR-99b and miR-192, and upregulating their targets FGFR3 and RB1. These findings offer novel insights into the understanding of underlying molecular mechanisms of NSCLC related with the nicotine effects.

Keywords: FGFR3; Nicotine; Non-small-cell lung cancer; RB1; miR-192; miR-99b.

MeSH terms

  • A549 Cells
  • Animals
  • Carcinoma, Non-Small-Cell Lung / metabolism*
  • Carcinoma, Non-Small-Cell Lung / pathology
  • Cell Proliferation
  • Dose-Response Relationship, Drug
  • Down-Regulation / drug effects
  • Down-Regulation / physiology
  • Epithelial-Mesenchymal Transition / drug effects
  • Epithelial-Mesenchymal Transition / physiology*
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Lung Neoplasms / metabolism*
  • Lung Neoplasms / pathology
  • MicroRNAs
  • Nicotine / pharmacology*
  • Nicotinic Agonists / pharmacology
  • Rats
  • Receptor, Fibroblast Growth Factor, Type 3 / agonists
  • Receptor, Fibroblast Growth Factor, Type 3 / biosynthesis*
  • Receptor, Fibroblast Growth Factor, Type 3 / genetics
  • Retinoblastoma Binding Proteins / agonists
  • Retinoblastoma Binding Proteins / biosynthesis*
  • Retinoblastoma Binding Proteins / genetics
  • Ubiquitin-Protein Ligases / biosynthesis*
  • Ubiquitin-Protein Ligases / genetics
  • Up-Regulation / drug effects
  • Up-Regulation / physiology

Substances

  • MIRN192 microRNA, human
  • MicroRNAs
  • Mirn99 microRNA, mouse
  • Nicotinic Agonists
  • RB1 protein, human
  • Retinoblastoma Binding Proteins
  • Fgfr3 protein, rat
  • Nicotine
  • Ubiquitin-Protein Ligases
  • Receptor, Fibroblast Growth Factor, Type 3