ABSTRACT: Background: Cervical cancer remains a leading cause of death in women due to metastasis to distant tissues and organs. Integrins are involved in cancer metastasis. However, whether integrin ?3 participates in cervical cancer metastasis is under investigation. In this study, we explored the effect and detailed mechanism through which integrin ?3 regulates cervical cell migration, invasion, and angiogenesis. Methods: First, we explored the mRNA and protein expression levels of integrin ?3 in cervical cancer cell lines and tissue samples obtained from patients. After knocking down the expression of integrin ?3 using shRNA, the proliferation, migration, and invasion of cervical cancer cells, as well as the possible signaling pathways involved, were investigated in vitro. In addition, tube formation, proliferation, and migration of human umbilical vein endothelial cells were tested to identify their effect on angiogenesis. Zebrafish tumor migration and nude mouse lung metastasis models were utilized for the in vivo analysis. Results: We examined samples from 142 patients with cervical cancer and 20 normal cervixes. Integrin ?3 was highly expressed in patients and predicted poor overall survival and disease-free survival. In SiHa cells, treatment with integrin ?3 shRNA induced the phosphorylation of protein focal adhesion kinase and enhanced focal adhesion. These events were mediated by the activation of c-Src and extracellular signal-regulated protein kinase cascades. Consequently, integrin ?3 increased the migratory ability of SiHa cells. In addition, knockdown of integrin ?3 decreased the tube formation, proliferation, and migration of human umbilical vein endothelial cells, as well as the levels of matrix metalloproteinase-9, indicating its effect on angiogenesis. Stable transfection with integrin ?3 shRNA reduced the migratory ability of SiHa cells in the zebrafish model and diminished lung metastasis in the xenograft mouse model. Conclusion: Integrin ?3 recruits the c-Src/extracellular signal-regulated protein kinase cascade, leading to phosphorylation of focal adhesion kinase. Moreover, it regulates focal adhesion, endowing cervical cancer cells with potentiated migratory and invasive ability, and promotes angiogenesis via matrix metalloproteinase-9. Our findings may shed light on the mechanism involved in cervical cancer metastasis and highlight integrin ?3 as a candidate prognostic biomarker and therapeutic target in patients with cervical cancer.
