The Role Of CXCL1 On The Epithelial-mesenchymal Trasition Of Breast Cancer And Its Underlying Mechanism

Objective This study was designed to investigate the effect of CXCL1 on the Epithelial-Msenchymal Transitionof Breast Cancer and its underlying mechanism.Methods In vitro,human breast cancer cell lines MCF-7 was cultured.Breast cancer cells were randomly divided into three groups: Control group,CXCL1(40ng/ml)group,CXCR2 inhibitor(SB225002 10um/ml)group.The morphological changes of cells were observed under microscope.E-cadherin,Vimentin,Snail,p-PI3 K and p-AKT were detected by ELISA assay.The effect of CXCL1 was evaluated on expression of EMT-related genes by RT-PCR.CCK8 and Cell Scratch assay were used to analyze the cell proliferation and migration.In vivo,48 samples of breast cancer tissue without any treatment were collected.Expression of CXCL1,CXCR2 and EMT related proteins E-cadherin and Vimentin were examined by IHC.Animal experiment: BALB/C mice were divided into two groups randomly: PBS group,CXCL1 group(n=20).In the CXCL1 group,intratumoral injection of CXCL1(0.1?g/g)was performed every 5 days,and intratumoral injection of CXCL1 was performed for 3 weeks,PBS group inject PBS only.Four weeks later,the mice were killed and fresh tissue was taken.Tumor volume and weight were determined.EMT related proteins E-cadherin and Vimentin were examined by IHC.Results In vitro,after CXCL1 treatment,MCF-7 cells showed typical mesenchymal morphology,and the proliferation and migration was significantly increased.The expression of E-cadherin was down-regulated,Vimentin and Snail were up-regulated,the phosphorylation level of the important members of PI3K/AKT signal pathwaywere up-regulated in the CXCL1 group.Compared with the control group and the CXCL1(40ng/ml)treatment group,after treated with SB225002,the expression of epithelial markers,E-cadherin was up-regulated and mesenchymal markers Vimentin and transcription factor Snail were down-regulated.The phosphorylation level of the PI3K/AKT signal pathway were down-regulated.Compared with the control group,E-cadherin m RNA were decreased in CXCL1 group while Vimentin m RNA was increased.In vivo,compared with paracancerous tissue,CXCL1 and CXCR2 were positively expressed in breast cancer tissues.The expression of epithelial markers,E-cadherin,was down-regulated and mesenchymal markers Vimentin was up-regulated.Animal experiments Tumor volume and weight were obviously bigger in the CXCL1 group.E-cadherin in the CXCL1 group was downregulated compared with control group,the expression of Vimentin was upregulated.Conclusion 1.CXCL1 promoted the EMT in breast cancer cells MCF-7.CXCL1/CXCR2 may induce epithelial-mesenchymal transformation in breast cancer cells by activating PI3K/AKT signaling pathway.2.CXCL1 CXCR2 and Vimentin were positively expressed in breast cancer tissues.BALB/C mice model of breast cancer was established.To investigate the effect of CXCL1 on the expression of EMT marker protein in breast cancer mice.