Abstract.Recently, fibroblast growth factor 18 (FGF18) expression was reported to be upregulated in colon cancer and ovarian cancer, and increased expression of FGF18 mRNA and protein is associated with tumor progression and poor overall survival in patients; however, its role in lung cancer remains to be explored. In the present study, the effect and underlying molecular mechanisms of FGF18 on H460 cells were investigated. Cell proliferation and cell cycle alterations were detected using a 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay and flow cytometry. A wound healing assay was conducted to detect cell migration. Reverse transcription-quantitative polymerase chain reaction and western blotting were performed to measure extracellular signal-regulated kinase (ERK), p38 and matrix metalloproteinase 26 (MMP26) expression. Knockdown of FGF18 using short interfering RNA (siRNA-FGF18) suppressed H460 cell proliferation, inhibited cell migration via the downregulation of MMP26 levels, with siRNA-FGF18 additionally inhibiting the ERK and p38 signaling pathway. The present study indicates that FGF18 serves an essential role in the growth and migration of non-small cell lung cancer (NSCLC) cells by regulating the ERK, p38 signaling pathways and MMP26 protein levels, suggesting that FGF18 may be a potential molecular drug target for the treatment NSCLC.

Fibroblast growth factor (FGF) 18 is a member of the FGF family and serves a key role in skeletal growth and development. The present study investigated the effect of FGF18 on pre‑osteoblast MC3T3-E1 cells and the signaling pathways involved by performing an alkaline phosphatase (ALP) assay and reverse transcription‑quantitative polymerase chain reaction. MC3T3‑E1 cells incubated in a culture medium supplemented with FGF18 exhibited increased viability when compared with the untreated control cells. In addition, ALP activity was decreased in MC3T3‑E1 cells treated with FGF18 plus an osteogenic medium (OM) for 7 and 14 days when compared with untreated and OM‑treated controls. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) results demonstrated that the expression of osteoblastic‑associated genes was significantly repressed in FGF18 plus OM‑treated MC3T3‑E1 cells, including ALP, collagen type I, osteocalcin, bone sialo protein and osterix. These results suggested that the expression levels of genes associated with osteogenesis were mainly repressed. In addition, combined treatment of MC3T3‑E1 cells with OM and FGF18 led to a significant reduction in mineral deposition when compared with the OM‑only treated group. Furthermore, FGF18 activated the extracellular signal‑regulated kinase pathway in MC3T3‑E1 cells, which may have been responsible for the observed decrease in the expression of osteoblastic‑associated genes. In conclusion, the results suggest that FGF18 may be involved in MC3T3‑E1 cell proliferation and osteoblastic differentiation.

Fibroblast growth factor 20 (FGF20) has a wide range of biological activities; its expression is most pronounced in neural tissues where it has functions in development and neuroprotection. Given these activities, interest in the clinical applications of FGF20 is rising, which will lead to increasing demand for active recombinant human FGF20 (rhFGF20). To improve the production of rhFGF20, an artificial gene encoding fgf20 was cloned into pET3a and expressed in E. coli BL21(DE3)pLysS. By optimizing induction conditions, we successfully induced large amounts of insoluble rhFGF20. Following solubilization and refolding of the rhFGF20 from inclusion bodies, it was purified by HiTrap heparin affinity chromatography to a purity of over 96% with a yield of 218 mg rhFGF20/100 g wet cells. The purified rhFGF20 could stimulate proliferation of both NIH 3T3 cells and PC-12 cells, measured by the MTT assay. In a model of Aβ25-35-induced apoptosis on PC-12 cells, rhFGF20 had a clear protective effect. RT-PCR and Western blot analysis of apoptosis-related genes and proteins revealed that the FGF20-derived protective mechanism was likely due to the relief of endoplasmic reticulum stress (ER stress). In conclusion, the approach described here may be a better means to produce active rhFGF20 in good quantity, thereby allowing for its future pharmacological and clinical use.

Human fibroblast growth factor 8b (FGF8b) was expressed based on a baculovirus expression vector system (BEVS) and identified as having a protective effect on Parkinson's disease. Immunoblotting demonstrated that rhFGF8b proteins were recognized by a human anti-FGF8b antibody. The multiplicity of infection and timing of harvest had a significant effect on protein yield and protein quality. Our results indicated that the rhFGF8b was first detectable at 36 h postinfection and reached a maximum at 60 h. A multiplicity of infection (MOI) of 8 pfu/mL was suitable for harvest. The target protein was purified by heparin-affinity chromatography. In vitro methylthiazol tetrazolium (MTT) assays demonstrated that the purified rhFGF8b could significantly stimulate proliferation of NIH3T3 cells. Furthermore, to elucidate the effect of rhFGF8b on Parkinson's disease, we used FGF8b pretreatment on a cell model of Parkinson's disease. The results indicated that rhFGF8b prevented necrosis and apoptosis of 1-METHYL-4-phenyl pyridine (MPP(+)) treated PC12 cells. Moreover, the effect of FGF8b on messenger RNA (mRNA) levels of apoptosis and ERS genes was investigated to clarify the molecular mechanisms of FGF8b. The results suggest that FGF8b exerts neuroprotective effects by alleviating endoplasmic reticulum (ER) stress during PD. These results suggest that FGF8b may be a promising candidate therapeutic drug for neurodegenerative diseases related to ER stress.

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