[Effect of chemokine CXCL12 and its receptor CXCR4 on proliferation, migration and invasion of epithelial ovarian cancer cells].

OBJECTIVE: To explore the effect of chemokine CXCL12 and its receptor CXCR4 on proliferation, migration and invasion of epithelial ovarian cancer cells.

METHODS: CXCR4 and CXCL12 mRNA and protein expression of human ovarian cancer cell line CAOV3 was detected by RT-PCR and immunocytochemistry. Integrin beta1 and vascular endothelial growth factor-C (VEGF-C) mRNA expression were detected in CAOV3 cells stimulated by CXCL12. The CAOV3 cells were divided into 6 groups: control group (un-stimulated), experimental group 1 (stimulated by 100 ng/ml CXCL12), experimental group 2 (stimulated by 10 ng/ml CXCL12), experimental group 3 (100 ng/ml CXCL12 and 10 microg/ml neutralizing CXCR4 antibody), experimental group 4 (100 ng/ml CXCL12 and 1 microg/ml CXCR4 antagonist AMD3100), experimental group 5 (10 microg/ml neutralizing CXCR4 antibody or ascites). Methyl thiazolyl tetrazolium (MTT) was used to analyze the effects of different concentrations of CXCL12 on CAOV3 cell proliferation. Transwell invasion chamber and reconstructed basement membrane (Matrigel) were used to evaluate effect of various concentrations of CXCL12 and ascites on CAOV3 cell migration and invasion.

RESULTS: CAOV3 cells expressed CXCR4 mRNA (0.70 +/- 0.10) and protein, but did not express CXCL12 mRNA or protein. Immunostaining of CXCR4 was mainly located in cytoplasm. CXCR4 mRNA was up-regulated after 100 ng/ml CXCL12 stimulation (1.24 +/- 0.14; t = -7.1088, P = 0.0021). Integrin beta1 mRNA was greatly increased at 3 hours by stimulation of 100 ng/ml CXCL12 (before and after stimulation 0.53 +/- 0.10, 1.53 +/- 0.16; P < 0.01), and VEGF-C mRNA showed significant increase at 24 hours by treatment with CXCL12 (before and after stimulation 0.52 +/- 0.09, 1.11 +/- 0.15; P < 0.05). Under serum-free sub-optimal culture conditions, experimental group 1 greatly enhanced cell proliferation in CAOV3 cells compared with control group and experimental group 2 (respectively 0.428 +/- 0.051, 0.325 +/- 0.045, 0.328 +/- 0.039; P < 0.05). Experimental group 1 was strongly inhibited compared with experimental groups 3 and 4 (the latter two groups respectively 0.356 +/- 0.031, 0.373 +/- 0.029; P < 0.05). There was no significant difference between experimental group 5 (0.349 +/- 0.038) and control group (P > 0.05). Experimental group 1 stimulated the migration and invasion of CAOV3 cells in chemotaxis assay compared with control group and experimental group 2 (number of cell migration respectively 523.3 +/- 25.2, 108.0 +/- 7.2, 211.7 +/- 24.7, number of cell invasion respectively 39.3 +/- 4.0, 4.0 +/- 1.0, 15.7 +/- 3.1; P < 0.01). This enhancing effect of experimental group 1 was strongly inhibited compared with experimental groups 4 and 5 (P < 0.05). The number of migrating and invading cells in experimental group 5 (migration: 706.6 +/- 30.6, invasion: 61.7 +/- 7.6) was significantly higher than that of experimental group 1 (P < 0.05).

CONCLUSIONS: This in vitro study shows CXCL12 promote proliferation, migration, invasion of ovarian cancer cell line CAOV3, and up-regulate integrin beta1 and VEGF-C expression, and these effects are strongly inhibited by neutralizing CXCR4 antibody. It suggests CXCL12 and its receptor CXCR4 may play important roles in ovarian cancer growth and metastasis.