The circular RNA ciRS-7 has been reported to be involved in the pathogenesis of various tumors, including gastric and colorectal cancer. However, the role of ciRS-7 in esophageal squamous cell carcinoma (ESCC) remains unsolved. In this study, we found that the ciRS-7 expression was significantly upregulated in ESCC cancer tissues compared with matched normal tissues and associated with poor patient survival. Overexpression of ciRS-7 abrogated the tumor-suppressive roles of miR-7 including cell proliferation, migration and invasion in vitro as well as tumor growth and lung metastasis in vivo. Mechanistically, ciRS-7 functioned as the sponge of miR-7 and reactivated its downstream HOXB13-mediated NF-κB/p65 pathway. Conclusively, our findings demonstrate how ciRS-7 induces malignant progression of ESCC and that ciRS-7 may act as a novel prognostic marker and therapeutic target for this lethal disease.

The long non-coding RNA (lncRNA) NKILA (nuclear transcription factor NF-κB interacting lncRNA) functions as a suppressor in human breast cancer and tongue cancer. However, the clinical significance and biological roles of NKILA in esophageal squamous cell carcinoma (ESCC) remain unknown. In this study, we showed that NKILA was downregulated in ESCC tissues and cancer cells compared with their normal counterparts. Low NKILA expression correlated with large tumor size and advanced TNM stage, and predicted poor overall and disease-free survival of ESCC patients. Further loss- and gain-of-function assays indicated that NKILA inhibited proliferation and migration of ESCC cells in vitro, suppressed tumor growth and lung metastasis in vivo. Mechanistically, NKILA could inhibit phosphorylation of IκBα, suppress p65 nuclear translocation and downregulate the expression of NF-κB target genes in ESCC cells. These results suggest NKILA could suppress malignant development of ESCC via abrogation of the NF-κB signaling and may potentially serve as a prognostic marker for ESCC.

MicroRNAs (miRNAs) are a class of small non-coding RNAs approximately 18-22 nucleotides in length, which play an important role in malignant transformation. The roles of miR-192 as an oncogene or tumor suppressor in solid tumors have been previously reported. However, little is known about the role of miR-192 in human acute myeloid leukemia. The results of the present study indicate that miR-192 is significantly downregulated in specimens from acute myeloid leukemia patients. Functional assays demonstrated that overexpression of miR-192 in NB4 and HL-60 cells significantly inhibited cell proliferation compared with that in control cells, and induced G0/G1 cell cycle arrest, cell differentiation, and apoptosis in vitro. Dual-luciferase reporter gene assays showed that miR-192 significantly suppressed the activity of a reporter gene containing the wild type 3'-UTR of CCNT2, but it did not suppress the activity of a reporter gene containing mutated 3'-UTR of CCNT2. QRT-PCR and Western blot assays showed that miR-192 significantly downregulated the expression of CCNT2 in human leukemia cells. Exogenous expression of CCNT2 attenuated the cell cycle arrest induced by miR-192 in NB4 and HL-60 cells. Collectively, miR-192 inhibits cell proliferation and induces G0/G1 cell cycle arrest in AML by regulating the expression of CCNT2.