Circular RNAs with exonic sequences represent a special form of non-coding RNAs, discovered by analyzing a handful of transcribed genes. It has been observed that circular RNAs function as microRNA sponges. In the present study, we investigated whether the expression of circular RNAs is altered during the development of esophageal squamous cell carcinoma (ESCC). Using a TaqMan-based reverse transcriptase polymerase chain reaction assay, the relationship between cir-ITCH and ESCC was analyzed in a total of 684 ESCC and paired adjacent non-tumor tissue samples from eastern and southern China. We found that cir-ITCH expression was usually low in ESCC compared to the peritumoral tissue. The functional relevance of cir-ITCH was further examined by biochemical assays. As sponge of miR-7, miR-17, and miR-214, cir-ITCH might increase the level of ITCH. ITCH hyper expression promotes ubiquitination and degradation of phosphorylated Dvl2, thereby inhibiting the Wnt/β-catenin pathway. These results indicate that cir-ITCH may have an inhibitory effect on ESCC by regulating the Wnt pathway.

Background: Though esophageal cancer is three to four times more common among males than females worldwide, this type of cancer still ranks in the top incidence among women, even more than the female specific cancer types. The occurrence is currently attributed to extrinsic factors, including tobacco use and alcohol consumption. However, limited attention has been given to gender-specific intrinsic genetic factors, especially in female. Methods: We re-annotated a large cohort of microarrays on 179 ESCC patients and identified female-specific differently expressed lncRNAs. The associations between FMR1-AS1 and the risk and prognosis of ESCC were examined in 206 diagnosed patients from eastern China and validated in 188 additional patients from southern China. The effects of FMR1-AS1 on the malignant phenotypes on female ESCC cells were detected in vitro and in vivo. ChIRP-MS, reporter gene assays and EMSA were conducted to identify the interaction and regulation among FMR1-AS1, TLR7 and NFκB. Results: We found FMR1-AS1 expression is exclusively altered and closely associated with the level of sXCI in female ESCC patients, and its overexpression may correlate to poor clinical outcome. ChIRP-MS data indicate that FMR1-AS1 could be packaged into exosomes and released into tumor microenvironment. Functional studies demonstrated that FMR1-AS1 could bind to endosomal toll-like receptor 7 (TLR7) and activate downstream TLR7-NFκB signaling, promoting the c-Myc expression, thus inducing ESCC cell proliferation, anti-apoptosis and invasion ability. Exosome incubation and co-xenograft assay indicate that FMR1-AS1 exosomes may secreted from ESCC CSCs, transferring stemness phenotypes to recipient non-CSCs in tumor microenvironment. Furthermore, we also found a correlation between the serum levels of FMR1-AS1 and the overall survival (OS) of the female ESCC patients. Conclusions: Our results highlighted exosomal FMR1-AS1 in maintaining CSC dynamic interconversion state through the mechanism of activating TLR7-NFκB signaling, upregulating c-Myc level in recipient cells, which may be taken as an attractive target approach for advancing current precision cancer therapeutics in female patients.

Long intergenic noncoding RNAs (lincRNAs) have critical regulatory roles in cancer biology; however, the contributions of lincRNAs to esophageal squamous cell carcinoma (ESCC) have been infrequently explored. The aim of this study was to explore the contribution of lincRNAs, located at ESCC susceptibility loci identified by genome-wide association studies, to the risk and prognosis of ESCC. The associations between lincRNAs and the risk and prognosis of ESCC were analyzed in 358 diagnosed patients from eastern China, and the findings were validated in 326 additional patients from southern China. Functional relevance of lincRNAs was further examined by biochemical assays. We found that lincRNA-uc002yug.2 was commonly overexpressed in ESCC compared with paired peritumoral tissue in eastern and southern Chinese populations. The expression levels of lincRNA-uc002yug.2 in ESCC might be a prognostic factor for survival. Moreover, lincRNA-uc002yug.2 promoted a combination of RUNX1 and alternative splicing (AS) factors in the nucleus to produce more RUNX1a, the short isoform and inhibitor of RUNX1, and reduce CEBPα (CCAAT/enhancer-binding protein-α) gene expression, thereby promoting ESCC progression. These results indicated that lincRNA-uc002yug.2 might involve in AS of RUNX1/AML1 and serve as a predictor for esophageal cancer and prognosis.

Interleukin-23 receptor (IL-23R) is a key element in the T-helper 17 cell-mediated inflammatory process, which plays an important role in the pathogenesis of cancer. In this study, we examined whether genetic polymorphisms in IL-23R are associated with cancer risk in 4936 cancer patients and 5664 control subjects from eastern and southern Chinese populations. We found that the C allele of the rs10889677A>C polymorphism in the 3'-untranslated region of IL-23R was inversely associated with risk of multiple types of cancer, including breast cancer, lung cancer and nasopharyngeal carcinoma. Healthy controls who harbored the rs10889677C allele had significantly decreased cancer risk (odds ratio = 0.74, 95% confidence interval = 0.71-0.78) compared with those who harbored the rs10889677A allele. Biochemical analysis demonstrated that the rs10889677A allele disrupted the binding site for the microRNA miR-let-7f, thereby increasing the transcription of the IL-23R in vitro and in vivo. Furthermore, cancer-free individuals carrying the rs10889677CC homozygous genotype had a lower proportion of regulatory T cells (Tregs) and a higher T-cell proliferation rate upon stimulation with concanavalin A than individuals carrying the rs10889677AA homozygous genotype. Our findings indicate that the IL-23R rs10889677A>C polymorphism may influence T-cell proliferation, resulting in changes in the levels of Tregs in vivo and modifying cancer susceptibility.

Thousands of long intergenic non-protein coding RNAs (lincRNAs) have been identified in mammals in genome-wide sequencing studies. Some of these RNAs have been consistently conserved during the evolution of species and could presumably function in important biologic processes. Therefore, we measured the levels of 26 highly conserved lincRNAs in a total of 176 pairs of endometrial carcinoma (EC) and surrounding non-tumor tissues of two distinct Chinese populations. Here, we report that a lincRNA, , which possesses an ultra-conserved region, is aberrantly down-regulated during the development of EC. Nevertheless, is a p53-targeting lincRNA acting along with heterogeneous nuclear ribonucleoproteins as a suppressive cofactor, which locally reinforces p53-mediated suppression of , an evolutionarily conserved neighboring gene of and putatively associated with increased tumor aggressiveness, during anti-tumor processes. overexpression could lower the levels of and slow the development of malignant phenotypes of EC both and Moreover, significantly increased the 50% inhibitory concentration of paclitaxel in EC cells and increased the sensitivity of xenograft mice to paclitaxel. These findings indicate that can influence expression as a locus-restricted cofactor for p53-mediated gene suppression, thus impacting EC malignancies and chemosensitivity to paclitaxel.