Fig. 2: Nicotine facilitated the malignant metastasis of LSCC by upregulating CHRNA5.

A CCK-8 assay was performed in four LSCC cell lines cultured with varying concentrations of nicotine (0.2–20 μM). B Wound healing assay revealed that 20-μM nicotine enhanced the proliferation of LSCC cells. Scale bar: 500 μm. Transwell migration (C) and invasion (D) assays demonstrated that 20-μM nicotine facilitated the metastasis of LSCC cells. Scale bar: 100 μm. E Protein–protein interaction network of nAChRs. Expression of nAChRs following nicotine stimulation in AMC-HN8 (F), FD-LSC-1 (G), FD-LS-6 (H) and Tu686 (I) cells. (J) Protein expression of CHRNA5 after nicotine stimulation. GAPDH served as a loading control. K Immunofluorescence staining revealed that CHRNA5 (green) was primarily localised in the cell membrane and cytoplasm and that nicotine upregulated CHRNA5 (green) in LSCC cells. Scale bar: 20 μm.