Background: Circular RNA (circRNA) has emerged as an important regulator in the progression of human diseases. However, the role of circRNAs in ovarian cancer remains largely unknown.
Materials and Methods: DNA sequencing and PCR were used to identify the existence and expression of circKRT7. The targeting relationship between circKRT7/miR-29a-3p and miR-29a-3p/COL1A1 was verified by fluorescence reporter assay. In vitro, colony formation, transwell and wound healing assay were used to detect the effects of circKRT7 and miR-29a-3p on the proliferation, migration and invasion ability of ovarian cancer cells. In vivo, xenograft tumor model was performed to validate the role of circKRT7 and miR-29a-3p in tumor growth.
Results: We found that circKRT7 can promote the proliferation and metastasis of ovarian cancer cells by absorbing miR-29a-3p, which leads to the up-regulation of COL1A1 . In vitro, knock-down of circKRT7 can inhibit the migration and invasion of ovarian cancer cells. This effect of circKRT7 is achieved by adsorbing miR-29a-3p and subsequently COL1A1  release. In vivo experiments, the reduction of circKRT7 expression can also slow tumor growth, and this inhibition was partly counteracted after miR-29a-3p repression.
Conclusion: Overall, circKRT7 promotes EMT-related cell progression by absorbing miR-29a-3p in ovarian cancer. This suggests the crucial role of circular RNA in the malignant evolution in cancer.
Keywords: ovarian cancer, KRT7, circular RNA, EMT