The Role of CCL20-CCR6 Axis in Ovarian Cancer Metastasis

BACKGROUND: Chemokine networks play a key and complex role in tumor progression. CCL20 and its unique receptor CCR6 have been reported to mediate malignant biological activities in various cancers, but their role in ovarian cancer metastasis remains unclear. PURPOSE: Our study aims to explore the effect of CCL20-CCR6 axis on ovarian cancer metastasis and its potential mechanism. METHODS: The transwell assay was used to detect the cell migration and invasion after CCL20 treatment. The CCK-8 assay was used to detect the cell viability after CCL20 treatment and CCR6 depletion. The mRNA and protein expression were assayed through qRT-PCR and Western blotting. The siRNAs and CRISPR-Cas9 system were adopted to suppress CCR6 expression. Intraperitoneal xenograft mouse model was constructed to test the pro-metastasis effect of CCL20-CCR6 axis in vivo. The differentially expressed genes induced by CCL20 were identified through RNA-sequencing, and immunohistochemistry staining was used to detect their protein expression in tumor tissues. RESULTS: Our results revealed that CCL20 treatment selectively promoted the migration and invasion of CCR6(high) ovarian cancer cells, but had no effect on CCR6(low) cells. Blockade of CCR6 expression effectively reversed the cell migration and invasion induced by CCL20 stimulation. Animal experiment proved that CCL20-CCR6 axis mediated ovarian cancer metastasis in vivo. The differentially expressed genes after CCL20 stimulation were associated with metastasis, and CCL20 induced an increased expression of CDH2 and VCAN and decreased CDH1 expression in cancer cells. Moreover, CCL20 stimulated the expression of N-cadherin and versican in tumor tissues and inhibited the expression of E-cadherin, while CCR6 knockout successfully blocked the expression changes. CONCLUSION: Our findings revealed that CCL20-CCR6 axis promotes ovarian cancer metastasis both in vivo and in vitro, probably through increasing cancer cell adhesion and epithelial–mesenchymal transition. Blockade of CCL20-CCR6 axis might become a novel anti-tumor therapeutic target for ovarian cancer.