Abstract: Objective Esophageal cancer is a serious threat to human health, and the metabolic pattern of tumor cells is dominated by glycolysis. This study analyzed the mechanisms regulating glycolysis in esophageal cancer cells. Methods The expression levels of Circular RNA lysophosphatidic acid receptor 3 (CircLPAR3), microRNA-143-5p (miR-143-5p) and ubiquitin-specific protease 14 (USP14) were measured using quantitative real-time (qRT-PCR). The extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) were measured using Seahorse XF 24 Extracellular Flux Analyzer. The expression levels of HK2 (a key enzyme of glycolytic pathway) was measured by Western blotting. The target binding site of CircLPAR3 to miR-143-5p and that of miR-143-5p to USP14 were all predicted by the Starbase database and verified through dual luciferase gene reporter assay. Results CircLPAR3 was highly expressed in the esophageal cancer cell lines, especially in the KYSE450 cell lines. At the same time, KYSE450 cells had lower miR-143-5p expression level and higher USP14 expression level. Compared to the Het-1A group, the KYSE450 group showed increased protein expression level of HK2, along with an increased ECAR and a reduced overall glycolytic OCR. Knockdown of CircLPAR3 expression resulted in reduced protein expression levels of cellular HK2, reduced ECAR and increased overall glycolytic OCR. Inhibition of miR-143-5p expression was able to partially reverse the suppression of cellular glycolysis induced by the inhibition of CircLPAR3 expression. The dual luciferase gene reporter assay verified the targeting relationship between CircLPAR3 and miR-143-5p, as well as the targeting relationship between miR-143-5p and USP14. Conclusion Circular RNA LPAR3 regulates the glycolytic pathway in esophageal cancer cells by regulating the miR-143-5p / USP14 pathway.

Key words: circular RNA lysophosphatidic acid receptor 3, miR-143-5p, ubiquitin-specific protease 14, esophageal cancer, glycolysis