AUTHOR=Fei Zhenghua , Wang Yanfen , Gu Yuyang , Xie Rongrong , Hao Qiongyu , Jiang Yiyan TITLE=CircKIF5B Promotes Hepatocellular Carcinoma Progression by Regulating the miR-192 Family/XIAP Axis JOURNAL=Frontiers in Oncology VOLUME=Volume 12 - 2022 YEAR=2022 URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2022.916246 DOI=10.3389/fonc.2022.916246 ISSN=2234-943X ABSTRACT=Abstract Background: The long-term prognosis of HCC (hepatocellular carcinoma) with metastasis remains extremely poor. CircRNAs are promising as critical biological markers in identifying disease mechanisms and precise diagnoses in developing new effective treatments. However, the role of circRNAs aberrant expression in HCC progression remains largely unknown. Methods: CircKIF5B location was investigated by RNA fluorescence in situ hybridization (RNA-FISH). RNase R treatment and Real-Time Quantitative RT-PCR (qRT-PCR) were performed for circRNA determination. Transwell chamber assays examined the chemotactic migration and invasion of liver cancer cells. Results: This study identified the circRNA circKIF5B originating from exon 1, 2, and 3 of the KIF5B gene. Importantly, we found that circKIF5B circRNA, rather than KIF5B linear mRNA, was notably upregulated in liver cancer cell lines and tissues. Moreover, we found that silencing circKIF5B markedly reduced the proliferation, invasion, and metastasis of liver cancer cells by sponging the miR-192 family, decreasing the expression of X-linked inhibitor of apoptosis (XIAP). Conclusion: Our data demonstrate that circKIF5B can regulate XIAP expression via sponging miR-192 and miR-215 competing for the ceRNA mechanism, indicating that circKIF5B may act as an essential upstream regulator and providing mechanistic evidence to support the view that circKIF5B/miR-192s/XIAP is a promising therapeutic target in the treatment of liver cancer.