CircTMCC1 enhances radioresistance in esophageal squamous cell carcinoma by upregulating MYC via miR-186-3p sponging

The involvement of circRNA in the radiosensitivity of various malignancies has been well established; however, its specific regulatory function and underlying mechanisms in esophageal squamous cell carcinoma (ESCC) radiosensitivity remain largely unexplored. In this study, differentially expressed circRNAs were identified in ESCC tissues and cells exhibiting either radiosensitivity or resistance. Notably, circTMCC1 was found to be upregulated in radioresistant ESCC tissues and was predominantly localized in the cytoplasm. In both in vivo and in vitro models, silencing of circTMCC1 enhanced the radiosensitivity of ESCC cells. Mechanistic investigations further demonstrated that circTMCC1 acts as a molecular sponge for miR-186-3p, thereby promoting MYC expression and contributing to radioresistance in ESCC. This study identifies a novel role for the circTMCC1/miR-186-3p/MYC axis in regulating radioresistance in ESCC, suggesting the potential for new therapeutic strategies in ESCC radiotherapy.