Circular RNA ciRS‐7 inhibits autophagy of ESCC cells by functioning as miR‐1299 sponge to target EGFR signaling

Abstract

Autophagy is a kind of intracellular degradation pathway which could be regulated by many noncoding RNAs. ciRS‐7, also called CDR1as, is a circular RNA that is relatively well studied at present. In our recent study, we have found that the expression of ciRS‐7 is abnormally increased in the esophageal squamous cell carcinoma (ESCC), and may function as an oncogene to accelerate ESCC progression through sponging miR‐876‐5p. Meanwhile, another study showed that ciRS‐7 is highly expressed in the triple‐negative breast cancer (TNBC) and may function as a competing endogenous RNA of miR‐1299 to maintain the high migration and invasive capacity of TNBC cells. Of interest, in the present work, we observed that ciRS‐7 could inhibit starvation or rapamycin‐induced autophagy of ESCC cells and miR‐1299 promotes starvation or rapamycin‐induced autophagy of ESCC cells. Mechanically, miR‐1299 could directly bind to the 3′‐untranslated region of epidermal growth factor receptor (EGFR) and then affects its downstream Akt‐mTOR pathway in ESCC cells. Consistent with our past findings, ciRS‐7 could also sponge miR‐1299 in ESCC cells. Taken together, this study has shed light on that circular RNA ciRS‐7 inhibits autophagy of ESCC cells by functioning as miR‐1299 sponge to target EGFR signaling.