Silencing of hsa_circ_0009035 suppresses cervical progression and enhances radiosensitivity through miR-889-3p-dependent regulation of HOXB7.

Circular RNAs (circRNAs), a novel type of endogenous non-coding RNAs, have been identified as critical regulators in human carcinogenesis. Here, we investigated the precise actions of hsa_circ_0009035 in the progression and radioresistance of cervical cancer (CC). The levels of hsa_circ_0009035, microRNA (miR)-889-3p and homeobox B7 (HOXB7) were detected by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. Ribonuclease R (RNase R) and Actinomycin D assays were used to assess the stability of hsa_circ_0009035. Cell proliferation, cell cycle progression, apoptosis, migration and invasion were gauged by the Cell Counting Kit-8 (CCK-8), flow cytometry and transwell assays, respectively. Cell colony formation and survival were determined by the colony formation assay. Targeted correlations among hsa_circ_0009035, miR-889-3p and HOXB7 were examined by the dual-luciferase reporter, RNA immunoprecipitation (RIP) or RNA pull-down assay. Animal studies were performed to evaluate the impact of hsa_circ_0009035 on tumor growth. We found that hsa_circ_0009035 was highly expressed in CC tissues and cells, and it was associated with the radioresistance of CC patients. Moreover, the silencing of hsa_circ_0009035 inhibited CC cell proliferation, migration, invasion, and enhanced apoptosis and radiosensitivity in vitro and weakened tumor growth in vivo Mechanistically, hsa_circ_0009035 directly targeted miR-889-3p by binding to miR-889-3p, and hsa_circ_0009035 modulated HOXB7 expression through miR-889-3p. HOXB7 was a functional target of miR-889-3p in regulating CC progression and radioresistance in vitro, and hsa_circ_0009035 modulated CC progression and radioresistance in vitro by miR-889-3p. Our current study first identified hsa_circ_0009035 as an important regulation of CC progression and radioresistance at least in part through targeting the miR-889-3p/HOXB7 axis, highlighting its significance as a potential therapeutic target for CC treatment.