CircC6orf132 Facilitates Proliferation, Migration, Invasion, and Glycolysis of Gastric Cancer Cells Under Hypoxia by Acting on the miR-873-5p/PRKAA1 Axis.

Weizhi Chen,Yanhong Ji

doi:10.3389/fgene.2021.636392

Abstract

Background: Hypoxia is a crucial factor in the progression of various tumors, including gastric cancer (GC). Circular RNAs (circRNAs) are important regulators in GC, and this study focused on researching circC6orf132 in GC progression under hypoxia.Methods: In vitro experiments were performed in GC cells under hypoxia (1% O2). CircC6orf132, microRNA-873-5p (miR-873-5p), and protein kinase AMP-activated alpha 1 catalytic subunit (PRKAA1) levels were examined by real-time polymerase chain reaction (qRT-PCR). Colony formation assay and transwell assay were used for detecting cell proliferation and migration or invasion. Glycolytic metabolism was evaluated using lactate production, glucose uptake, and adenosine triphosphate (ATP) level and extracellular acidification rate (ECAR). Western blotting was performed for determining protein expression. The target interaction was analyzed by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. In vivo assay was conducted via mouse xenograft model.Results: The expression of circC6orf132 was significantly high in GC cells under hypoxia. Hypoxia-induced GC proliferation, migration, invasion, and glycolysis were reversed by silencing circC6orf132. CircC6orf132 targeted miR-873-5p; and the inhibition of circC6orf132 knockdown for the effects of hypoxia on GC cells was abrogated by miR-873-5p inhibitor. PRKAA1 was validated as a downstream gene of miR-873-5p, and miR-873-5p functioned as an anticancer molecule in GC cells under hypoxia by downregulating PRKAA1 level. CircC6orf132 could regulate PRKAA1 by sponging miR-873-5p. CircC6orf132/miR-873-5p/PRKAA1 axis could regulate GC progression under the hypoxic condition. CircC6orf132 downregulation reduced tumorigenesis in vivo through affecting the miR-873-5p/PRKAA1 axis.Conclusion: CircC6orf132 has been affirmed to promote proliferation, migration, invasion, and glycolysis in GC under hypoxia, partly by depending on the regulation of miR-873-5p/PRKAA1 axis.

Highlights

MATERIALS AND METHODSGastric cancer (GC), the fifth most common cancer, is one of the leading causes of cancer-related death around the world (Smyth et al, 2020)
protein kinase AMP-activated alpha 1 catalytic subunit (PRKAA1) was validated as a downstream gene of miR-873-5p, and miR-873-5p functioned as an anticancer molecule in gastric cancer (GC) cells under hypoxia by downregulating PRKAA1 level
The qRTPCR results indicated that circC6orf132 level was increased in a time-dependent manner after AGS and HGC-27 cells were exposed to hypoxia (Figures 1G,H)

Summary

Introduction

MATERIALS AND METHODSGastric cancer (GC), the fifth most common cancer, is one of the leading causes of cancer-related death around the world (Smyth et al, 2020). Due to the low diagnosis rate of early GC, most GC patients were diagnosed as advanced stage, and the median survival is less than 1 year (Tan, 2019, Smyth et al, 2020). Hypoxia is a significant factor for tumor diffusion and progression and is associated with cancer treatment (Hockel and Vaupel, 2001; Tatum et al, 2006). Hypoxia contributes to tumor glycolytic metabolism that provides energy for tumor proliferation and metastasis (Fang et al, 2008; Tian et al, 2020). To investigate GC pathogenesis under hypoxia is indispensable for early diagnosis and advanced therapy. Hypoxia is a crucial factor in the progression of various tumors, including gastric cancer (GC). Circular RNAs (circRNAs) are important regulators in GC, and this study focused on researching circC6orf132 in GC progression under hypoxia

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Conclusion