Fibroblast Growth Factor 18 Promotes The Growth,migration And Invasion Of MDA-MB231 Cells

Background: Fibroblast growth factor 18(FGF18)is a member of FGF family and it is involved in various type of physiology processes,such as embryonic development,chondrogenesis.Some studies have reported that FGF18 has an important effect in development of ovarian tumor,colorectal tumor and lung tumor via promoting the proliferation、migration and invasion of these tumor cells,and the expression level of FGF18 has a strong relation with the grade and prognosis of these tumor.However,there are few studies reporting the effect of FGF18 in breast cancer,and more researches should be carried on.Objective: Our study is to explore the biological effect and molecular mechanism of FGF18 in breast cancer cell MDA-MB231.Materials and methods: In vitro: CCK-8 proliferation assay and colony formation assay were used to test the effect of FGF18 on the proliferative ability of MDA-MB231 cells,and flow cytometric analysis was used to test the change of cell cycle progression.Wound healing scratch assay and Transwell assay were used to test the effect of FGF18 on the migratory and invasive ability of MDA-MB231 cells.Reverse transcription-quantitative polymerase chain reaction(q RT-PCR)and Western blot analysis were used to test the change of the expression of m RNA and protein of FGF18 as well as the related protein.We also used si RNA transfection to observe the change of cellular functions of MDA-MB231 cells after FGF18 gene been knocked out.In vivo: We divided the mice into four groups: FGF18 CK,FGF18 O,FGF18 KO,FGF18 O+ERK inhibitor.We observed the growth of tumor in mice with FGF18 overexpressed and knocked out contrasting with the tumor with FGF18 negatively controlled,and investigated if ERK inhibitor had the effect of suppressing the growth of tumor stimulated by FGF18.Results: In vitro: Proliferation: In the CCK-8 proliferation assay and colony formation assay,the cell proliferation number of MDA-MB231 cells with FGF18 was highly more than the control group(p<0.05).In flow cytometric analysis,the percentage of cell in G0/G1 phase increased and the percentage of cell in S phase decreased with stimulation of FGF18.Migration and invasion: In the wound healing scratch assay,the migratory distance of cell added with FGF18 was significantly longer than control group.In the Transwell assay,there were much more cells crossing the membrane stimulated with FGF18.Expression level of protein: Using the Western blot analysis,we found that the expression level of p-ERK、 c-Myc、N-cadherin、Vimentin and Snail 1 increased significantly because of the effect of FGF18.Reversion experiment: We used the si RNA to knock down the expression of FGF18,and the proliferation、migration and invasion of MDA-MB231 cells was depressed obviously.The protein expression level of p-ERK、c-Myc、N-cadherin、Vimentin and Snail 1 decreased as wel.In vivo: We investigated that the size of tumor tissue in the group of FGF18 O was much larger than FGF18 CK group,and the size of tumor tissue in the group of FGF18 KO was much smaller than FGF18 CK group.The tumor size in the group of FGF18 O + ERK inhibitor was obviously smaller than the group of FGF18 O.Conclusion: FGF18 promotes the proliferation、migration and invasion of breast cancer cell line MDA-MB231 via ERK/c-Myc signaling pathway and epithelial-to-mesenchymal transition.Therefore,FGF18 may play an important role in growth and metastasis of breast cancer cell line MDA-MB231 and FGF18 may be a potential treatment target of breast caner.