Association between circ_0004365 and cisplatin resistance in esophageal squamous cell carcinoma.

Cisplatin is one of the most predominant drugs for the chemotherapy of esophageal squamous cell carcinoma (ESCC); however, the underlying resistance mechanisms are still almost unknown. The present study performed RNA sequencing of human circular RNA (circRNA) in TE11 cells and cisplatin-resistant TE11 cells (TE11R). The expression profiles determined using CIRCexplorer2 revealed that the expression of circ_0004365, mapped on the Semaphorin 3C gene, was significantly greater in TE11R compared with in TE11. In reverse transcription-quantitative PCR, circ_0004365 expression was observed in human ESCC and non-tumor tissues and was significantly upregulated in ESCC tumor tissues after chemotherapy. Circ_0004365 expression was significantly upregulated in patients with poor pathological response (P=0.02). Furthermore, patients with advanced pT stage showed an upregulation in circ_0004365 expression after chemotherapy (P=0.02). The MTT assay revealed that knockdown of circ_0003465 in TE11 significantly decreased resistance to cisplatin. In conclusion, the present study suggested that circ_0004365 was associated with cisplatin resistance in ESCC and can be used as both a novel biomarker and a therapeutic target.