Introduction: Long non-coding RNAs (LncRNAs) have been demonstrated to play a vital role in human carcinogenesis. HOXA cluster antisense RNA 2 (HOXA-AS2), a 1048-bp lncRNA located between the HOXA3 and HOXA4 genes, is identified as an oncogene in several malignancies, including glioma. However, the biological functions of HOXA-AS2 and its underlying molecular mechanisms in glioma progression remain to be investigated.
Method: The expression of HOXA-AS2 and RND3 mRNA was determined using qRT-PCR analysis. The protein level of RND3 and EZH2 was measured by Western blot analysis. The biological function of HOXA-AS2 or RND3 in glioma was detected by CCK-8 assay, colony formation assays, transwell assay, and flow cytometry. Dual-luciferase reporter, RIP, RNA-protein pull down and ChIP assays were performed to explore the molecular mechanism of HOXA-AS2 in glioma. The effect of HOXA-AS2 in vivo was examined using xenograft tumor assay.
Results: HOXA-AS2 expression was increased in glioma tissues and cells. High HOXA-AS2 expression was associated with larger tumor size and advanced pathological stage. Functionally, knockdown of HOXA-AS2 suppressed cell proliferation and invasion, and promoted apoptosis. Mechanically, HOXA-AS2 epigenetically inhibited RND3 transcription by binding to EZH2. Moreover, overexpression of RND3 exerted similar tumor-suppressive effects to the depletion of HOXA-AS2. Furthermore, the anti-cancer effects induced by si-HOXA-AS2 were greatly reversed by silencing of RND3. Finally, knockdown of HOXA-AS2 impaired tumor growth in vivo possibly via increasing RND3 expression.
Conclusion: Taken together, HOXA-AS2 recruits EZH2 to the promoter region of RND3 and inhibits its expression, thereby facilitating glioma progression. Our findings provide a prospective therapeutic strategy for glioma intervention.
Keywords: glioma, lncRNA, HOXA-AS2, RND3, EZH2