CircRNA hsa_circ_100395 regulates miR-1228/TCF21 pathway to inhibit lung cancer progression.

Circular RNA (circRNA) is shown to participate in various tumors, including lung cancer. Although a few circRNAs involved in lung cancer are reported, whether circRNA negatively regulates lung cancer development remains elusive. In this study, we showed hsa_circ_100395 expression was decreased in lung cancer tissues. Besides, hsa_circ_100395 level was inversely correlated with TNM stage and metastases in lung cancer and low hsa_circ_100395 expression in patients predicted poor prognosis. Overexpression of hsa_circ_100395 dramatically inhibited lung cancer cell proliferation, arrested cell-cycle progression and reduced cell migration and invasion in vitro. Xenograft experiments showed that hsa_circ_100395 overexpression delayed tumor growth in vivo. Mechanistically, we showed hsa_circ_100395 serves as a sponge for miR-1228 targeting TCF21 in lung cancer. Rescue assays indicated that hsa_circ_100395 regulates lung cancer cell proliferation, migration and invasion through modulating miR-1228/TCF21 pathway. Altogether, our study reveals a novel regulatory loop that hsa_circ_100395/miR-1228/TCF21 axis modulates lung cancer development. ABBREVIATIONS: circRNA: circular RNA; miRNA: microRNA; RNA-FISH: RNA fluorescence in situy bridization; qRT-PCR: Reverse transcription and quantitative real-time PCR.