Abstract. Long non-coding RNAs (lncRNAs) have previously been reported to be involved in cancer invasion, proliferation and apoptosis. However, the association between the lncRNA, H19, and esophageal cancer (EC) has remained elusive. In the present study, reverse transcription quantitative-polymerase chain reaction revealed that the expression of H19 was significantly increased and associated with tumor depth and metastasis in 133 EC samples. Furthermore, MTT and Transwell assays revealed that overexpression of H19 in vitro promoted the proliferation and invasion of EC cell lines, whereas knockdown of H19 inhibited the proliferation and invasion of EC cell lines. In addition, it was identified that an upregulation of H19 induced epithelial-to-mesenchymal transition, while the opposite effect was observed following the downregulation of H19. In conclusion, H19 has a significant role in the development of EC and may serve as a potential prognostic marker and therapeutic target for EC. IntroductionEsophageal carcinoma (EC) is the eighth most aggressive and malignant type of cancer, with a high incidence that varies according to geographic location and ethnicity (1). Despite progress in the development of diagnostic and therapeutic options, the survival rates for EC patients remain poor. Therefore, the identification of novel genes involved in the tumorigenesis and development of EC is urgently required.Long non-coding RNAs (lncRNAs) are a class of RNAs that have been reported to be involved in the regulation, invasion, proliferation and apoptosis of multiple tumors (2,3). The association between H19 expression and the progression of various types of cancer has been demonstrated in previous studies. One study found that the overexpression of lncRNA H19 enhanced the carcinogenesis and metastasis of gastric cancer (4). MALAT-1, an abundant lncRNA present in many human cell types, has been suggested to regulate the alternative splicing of a subset of pre-messenger (m)RNAs by modulating serine/arginine splicing factor activity. This factor in turn regulates tissue or cell-type-specific alternative splicing in a phosphorylation-dependent manner (5). However, the role of H19 in EC is yet to be elucidated.The epithelial-to-mesenchymal transition (EMT) has an important role in the invasion of various types of cancer by transforming adherent and polarized epithelial cells into invasive and motile mesenchymal cells (6,7). A number of transcription factors involved in EMTs, including Twist and Snail, increase the expression level of mesenchymal markers, including fibronectin, collagen and Vimentin, and decrease the expression of epithelial markers, including E-cadherin. The breakdown of tight junctions results in the loss of epithelial markers and the acquisition of mesenchymal markers (8-10).In the present study, the expression levels of H19 in EC were investigated, in order to elucidate the role of H19 in EC. Materials and methods Clinical

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Objective. Esophageal cancer (ESCC) is reported to be the eighth most common malignant tumors worldwide with high mortality. However, the functions of majority circRNAs in ESCC requires to be further explored. Methods. This study identified differently expressed circRNAs in 3 paired ESCC using RNA-sequencing method. The interactions among circRNAs, miRNAs, and mRNAs were predicted using bioinformatics analysis. Results. In this study, using RNA-sequencing method and integrated bioinformatics analysis, 418 overexpressed circRNAs and 637 reduced circRNAs in ESCC sample were identified. Based on the mechanism that circRNAs could play as ceRNAs to modulate targets expression, circRNA-miRNA and circRNA-miRNA-mRNA networks were constructed in this study. Based on the network analysis, 7 circRNAs, including circ_0002255, circ_0000530, circ_0001904, circ_0001005, circ_0000513, circ_0000075, and circ_0001121, were identified as key circRNAs in ESCC. We found that circ_0002255 was related to the regulation of substrate adhesion-dependent cell spreading. circ_0001121 was involved in regulating nucleocytoplasmic transport. circ_0000513 played a key role in regulating Adherens junction, B cell receptor signaling pathway. Meanwhile, we observed circ_0000075 was involved in regulating zinc II ion transport, transition metal ion homeostasis, and angiogenesis. Conclusion. We thought this study could provide novel biomarkers for the prognosis of ESCC.

Background Lung cancer (LC) is a malignant tumor originating in the bronchial mucosa or gland of the lung. Circular RNAs (circRNAs) are proved to be key regulators of tumor progression. However, the regulatory effect of circ_0001421 on lung cancer tumorigenesis remains unclear. Methods The expression levels of circ_0001421, microRNA-4677-3p (miR-4677-3p) and cell division cycle associated 3 (CDCA3) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Methyl thiazolyl tetrazolium (MTT), Transwell and Tumor formation assays were performed to explore the role of circ_0001421 in LC. Glucose consumption and lactate production were examined by a Glucose assay kit and a Lactic Acid assay kit. Western blot was utilized to examine the protein levels of Hexokinase 2 (HK2) and CDCA3. The interaction between miR-4677-3p and circ_0001421 or CDCA3 was confirmed by dual-luciferase reporter assay. Results Circ_0001421 was increased in LC tissues and cells, and knockdown of circ_0001421 repressed cell proliferation, migration, invasion and glycolysis in vitro. Meanwhile, circ_0001421 knockdown inhibited LC tumor growth in vivo. Mechanistically, circ_0001421 could bind to miR-4677-3p, and CDCA3 was a target of miR-4677-3p. Rescue assays manifested that silencing miR-4677-3p or CDCA3 overexpression reversed circ_0001421 knockdown-mediated suppression on cell proliferation, migration, invasion and glycolysis in LC cells. Conclusion Circ_0001421 promoted cell proliferation, migration, invasion and glycolysis in LC by regulating the miR-4677-3p/CDCA3 axis, which providing a new mechanism for LC tumor progression.

Lung adenocarcinoma (LUAD) accounts for ~40% of lung cancer cases, and the 5‐year relative survival rate is no more than 1%. Dysregulation of components of striatin‐interacting phosphatase and kinase (STRIPAK) complexes is associated with various diseases, including cancer. Striatin‐interacting protein 2 (STRIP2), also called Fam40b, has been reported to regulate tumor cell growth and migration. Here, we investigated the role of STRIP2 in LUAD growth, migration and the underlying mechanisms. Analysis of data from The Cancer Genome Atlas database revealed that STRIP2 is highly expressed and predicted poor outcomes in patients with LUAD. Moreover, quantitative RT‐PCR (qRT‐PCR) analysis revealed that the mRNA expression of STRIP2 is greater in all tested LUAD cells than in a normal lung cell line. To investigate the function of STRIP2, we overexpressed STRIP2 in SPC‐A1 cells and depleted STRIP2 in Calu‐3 cells. Cell proliferation was evaluated by Cell Counting Kit‐8 and colony‐forming assays, and Transwell assay was employed to test cell invasion and migration. Our results indicate that STRIP2 depletion suppressed cell proliferation, invasion and migration in Calu‐3 cells, and overexpression of STRIP2 had the opposite effects in SPC‐A1 cells. Moreover, we discovered that STRIP2 depletion reduced the protein levels of p‐Akt and phosphorylated‐mammalian target of rapamycin (p‐mTOR) in Calu‐3 cells, whereas STRIP2 overexpression increased levels of these proteins in SPC‐A1 cells. Furthermore, we found that silencing of STRIP2 clearly enhanced protein levels of E‐cadherin and reduced levels of N‐cadherin, Vimentin and matrix metalloproteinase‐9 in Calu‐3 cells, whereas overexpression of STRIP2 had the opposite effect in SPC‐A1 cells. Our data indicate that STRIP2 promotes the proliferation and motility of LUAD cells, and this may be mediated through the regulation of the Akt/mTOR pathway and epithelial–mesenchymal transition. These results may facilitate the development of therapeutic strategies to treat LUAD.