LncRNA HOXA-AS2 Promotes Tumor Progression by Suppressing miR-567 Expression in Oral Squamous Cell Carcinoma

Abstract

Introduction

Growing evidence suggests that long non-coding RNAs (lncRNAs), such as lncRNA HOXA-AS2, are critical regulators involved in human cancer. However, the biological functions and detailed mechanisms underlying how lncRNA HOXA-AS2 affects oral squamous cell carcinoma (OSCC) remain unexplored.

Methods

The expression of lncRNA HOXA-AS2 and miR-567 was determined in OSCC cell lines and clinical tissues by quantitative real-time PCR (qRT-PCR). Target site prediction and luciferase report assays were used to explore their potential interaction and binding sites between lncRNA HOXA-AS2 and miR-567. Overexpression or silencing expression of lncRNA HOXA-AS2 was performed to confirm that miR-567 was suppressed by lncRNA HOXA-AS2. WST-1 assay, crystal staining assay, and cell cycle analysis were used to assess the cell viability and proliferation ability. The target gene of miR-567 was predicted by Targetscan and validated by luciferase report assay as well as qRT-PCR and Western Blot. Xenograft nude mice model was done to demonstrate that lncRNA HOXA-AS2 promoted cell proliferation via targeting miR-567/CDK8 in vivo.

Results

LncRNA HOXA-AS2 was up-regulated in OSCC cells and tissues with the expression of miR-567 decreased. The tissue lncRNA HOXA-AS2 expression was found to positively correlate with the TNM stage and lymph node metastasis of OSCC patients. In terms of the mechanism, we found that lncRNA HOXA-AS2 negatively regulates miR-567 expression via a direct interaction. Functionally, overexpression of lncRNA HOXA-AS2 significantly promoted OSCC cell proliferation, while knockdown of lncRNA HOXA-AS2 significantly inhibited it. We also observed that miR-567 directly targets the 3ʹ UTR of CDK8. Moreover, silencing lncRNA HOXA-AS2 inhibited tumor growth with the expression of miR-567 increased and CDK8 decreased in vivo.

Conclusion

LncRNA HOXA-AS2 was up-regulated in OSCC, and its up-regulation correlated with poor clinical outcomes. The lncRNA also promoted OSCC cell proliferation by directly binding to miR-567, leading to an increase in CDK8 expression. The potential prognostic value of lncRNA HOXA-AS2 should be explored in future studies.

Keywords:

• LncRNA HOXA-AS2
• MiR-567
• CDK8
• Oral squamous cell carcinoma
• Tumor progression

Acknowledgments

We are grateful to Dr. Liuyang Zhao from The Chinese University of Hong Kong for technical support.

Data Sharing Statement

The datasets used and/or analyzed during the current study are available from the corresponding author (Zongyue Zeng) upon reasonable request.

Ethics Approval and Consent to Participate

The animal use and care was approved by the Committee for Ethical Review of Research of The First Affiliated Hospital of Chongqing Medical University and all animal studies were performed according to the guidelines for the ethical review of laboratory animal welfare National Standard GB/T 35,892-2018 issued by the People’s Republic of China. The in vivo animal study was also carried out in compliance with the ARRIVE guidelines 2.0. The ethical consent for patient participation was approved by the Committee for Ethical Review of Research Involving Human Subjects of The First Affiliated Hospital of Chongqing Medical University according to the International Ethical Guidelines for Biomedical Research Involving Human Subjects (CIOMS). Written informed consent was provided by all of the patients who participated in the study. Meanwhile, all the experiments on the clinical samples were done in accordance with the Declaration of Helsinki.

Disclosure

The authors declare that they do not have any conflicts of interest.