Alterations in long non-coding RNAs (lncRNAs) are associated with human carcinogenesis. One group of lncRNAs, which are antisense in orientation to coding mRNAs (ASs), have been recently described in cancers but are poorly understood. We sought to identify ASs involved in human gastric cancer (GC) and to elucidate their mechanisms of action in carcinogenesis. We performed massively parallel RNA sequencing in GCs and matched normal tissues, as well as in GC-derived and normal gastric epithelial cell lines. One AS, designated KRT7-AS, was selected due to its marked upregulation and concordant expression with its cognate sense counterpart, KRT7, in GC tissues and cell lines. KRT7-AS formed an RNA-RNA hybrid with KRT7 and controlled KRT7 expression at both the mRNA and the post-transcriptional levels. Moreover, forced overexpression of the KRT7-overlapping region (OL) of KRT7-AS (but not its non-KRT7-overlapping portions) increased keratin 7 protein levels in cells. Finally, forced overexpression of full-length (FL) KRT7-AS or OL KRT7-AS (but not its non-KRT7-overlapping regions) promoted GC cell proliferation and migration. We conclude that lncRNA KRT7-AS promotes GC, at least in part, by increasing KRT7 expression.

Lung adenocarcinoma (LUAD) is the main subtype of lung cancer. In this study, we found that RBP Mex3a was significantly upregulated in LUAD tissues and elevated Mex3a expression was associated with poor LUAD prognosis and metastasis. Furthermore, we demonstrated that Mex3a knockdown significantly inhibited LUAD cell migration and invasion in vitro and metastasis in nude mice. Transcriptome sequencing indicated that Mex3a affected gene expression linked to ECM-receptor interactions, including laminin subunit alpha 2(LAMA2). RNA immunoprecipitation (RIP) assay revealed Mex3a directly bound to LAMA2 mRNA and Mex3a increased the instability of LAMA2 mRNA in LUAD cells. Furthermore, we discovered that LAMA2 was surprisingly downregulated in LUAD and inhibited LUAD metastasis. LAMA2 knockdown partially reverse the decrease of cell migration and invasion caused by Mex3a knockdown. In addition, we found that both Mex3a and LAMA2 could influence PI3K-AKT pathway, which are downstream effectors of the ECM-receptor pathway. Moreover, the reduced activation of PI3K-AKT pathway in caused by Mex3a depletion was rescued by LAMA2 knockdown. In conclusion, we demonstrated that Mex3a downregulates LAMA2 expression to exert a prometastatic role in LUAD. Our study revealed the prognostic and prometastatic effects of Mex3a in LUAD, suggesting that Mex3a can serve as a prognostic biomarker and a target for metastatic therapy.

BackgroundRecent studies observed that altered energy metabolism has become widespread in cancer cells along with other cancer-associated traits that have been accepted as hallmarks of cancer. Akt signaling pathway is involved in the aerobic glycolysis program. However, mechanisms underlying the regulation of aerobic glycolysis and Akt activity in gliomas remain unclear. MicroRNAs are a group of small non-coding RNAs that can function as endogenous RNA interference to regulate expression of targeted genes. This study was conducted to detect the function of miR-7 targeting insulin-like growth factor 1 receptor (IGF-1R), which is an upstream regulator of Akt.MethodsMicroRNA expression data for gliomas and normal controls were downloaded from The Cancer Genome Atlas (TCGA) database. Quantitative real-time PCR was used to measure the microRNA-7 (miR-7) expression level, and Western blot was performed to detect protein expression in U87 and U251 cells. Colony formation assay and glycolysis stress test were also conducted. Luciferase reporter assay was used to identify the mechanism of IGF-1R and miR-7 regulation.ResultsmiR-7 was downregulated in human glioma tissues based on TCGA database. Forced expression of miR-7 or IGF-1R knockdown inhibited colony formation and glucose metabolic capabilities of glioma cells in vitro and decreased the p-Akt expression level. Bioinformatics analysis results indicated that IGF-1R could be a target of miR-7. Western blot and luciferase reporter assays showed that miR-7 modulated IGF-1R expression by directly targeting the binding site within the 3′-untranslated region.ConclusionsThis study provides the first evidence that miR-7 inhibits cellular growth and glucose metabolism in gliomas, at least partially, by regulating the IGF-1R/Akt signaling pathway. Therefore, miR-7 is a promising molecular drug for glioma treatment.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_211

Lung cancer is the leading cause of cancer-related death worldwide. Non-small-cell lung cancer (NSCLC) is the most common pathological type of lung cancer, divided into squamous cell carcinoma and adenocarcinoma. Despite better techniques of surgery and improvement in adjuvant and neoadjuvant therapy, the median survival of advanced NSCLC is only 8-10 months. With increased understanding of molecular alternations in NSCLC, considerable efforts have focused on the development of personalized molecular-targeted therapies. The PI3K/AKT/mTOR pathway regulates tumor development, growth, and proliferation of NSCLC. Various novel inhibitors targeting this pathway have been identified in preclinical studies or clinical trials. Some genetic alternations may be considered sensitive or resistant biomarkers to these inhibitors. Sometimes, upregulation of RTK and the downstream PI3K pathway or upregulation of the ERK pathway by compensatory feedback reactivation in response to these inhibitors also lead to drug resistance. Therefore, combination therapy of these inhibitors and other targeted inhibitors such as EGFR-TKI or MEK inhibitors according to genetic status and categories of inhibitors is required to enhance the efficacy of these inhibitors. Here, we reviewed the genetic status of the PI3K/AKT/mTOR pathway in NSCLC and the novel inhibitors targeting this pathway in preclinical or clinical studies, exploring the possible genetic alternations related to different inhibitors and the means to enhance the antitumor effect in NSCLC.

Thymoquinone (TQ) has been reported to possess anti-tumor activity in various types of cancer. However, its effects and molecular mechanism of action in hepatocellular carcinoma (HCC) are still not completely understood. We observed that TQ inhibited tumor cell growth in vitro, where treatment with TQ arrested the cell cycle in G1 by upregulating p21 and downregulating cyclinD1 and CDK2 expression; moreover, TQ induced apoptosis by decreasing expression of Bcl-2 and increasing expression of Bax. Simultaneously, TQ demonstrated a suppressive impact on the Notch pathway, where overexpression of NICD1 reversed the inhibitory effect of TQ on cell proliferation, thereby attenuating the repressive effects of TQ on the Notch pathway, cyclinD1, CDK2 and Bcl-2, and also diminishing upregulation of p21 and Bax. In a xenograft model, TQ inhibited HCC growth in nude mice; this inhibitory effect in vivo, as well as of HCC cell growth in vitro, was associated with a discernible decline in NICD1 and Bcl-2 levels and a dramatic rise in p21 expression. In conclusion, TQ inhibits HCC cell growth by inducing cell cycle arrest and apoptosis, achieving these effects by repression of the Notch signaling pathway, suggesting that TQ represents a potential preventive or therapeutic agent in HCC patients.

Esophageal squamous cell carcinoma (ESCC) has a poor prognosis due to high lymphatic metastatic recurrence rates after Ivor Lewis esophagectomy. We sought to investigate the correlation between tumor necrosis factor alpha-induced protein 8 (TNFAIP8) expression and postoperative lymphatic recurrence in patients with pN0 ESCC. One hundred twenty-two patients with pN0 ESCC undergoing Ivor Lewis esophagectomy were enrolled in this study. TNFAIP8 overexpression was found in 73 (59.8 %) tumor specimens. The 3-year lymphatic metastatic recurrence rate among TNFAIP8-overexpressing patients was significantly higher than in TNFAIP8-negative patients (p = 0.003). Multivariate Cox regression identified TNFAIP8 overexpression as an independent risk factor for lymphatic recurrence (p = 0.048). TNFAIP8 messenger RNA (mRNA) levels were significantly higher in patients with lymphatic recurrence than in patients without tumor recurrence (p = 0.019). Stable silencing of TNFAIP8 expression in ESCC-derived cells (Eca109) reduced proliferation, motility, and invasion and induced apoptosis. In addition, transient silencing of TNFAIP8 expression decreased cell motility and invasion and increased apoptosis in a second ESCC-derived cell line (KYSE150). Taken together, these findings suggest that TNFAIP8 overexpression is a potential biomarker to identify pN0 ESCC patients at higher risk of lymphatic recurrence who may benefit from adjuvant therapy.

Background: Esophageal squamous cell carcinoma (ESCC) is the leading cause of cancer-related mortality.While recent studies have documented the presence of extrachromosomal circular DNAs (eccDNAs) in various tumors, to date, there have been no studies examining the distribution and function of eccDNAs in ESCC.Methods: The eccDNAs from three surgically matched ESCC tissue samples were extracted and amplified by rolling circle amplification after removal of linear DNA and mitochondrial circular DNA. Highthroughput eccDNA sequencing and bioinformatics analysis was performed to study the distribution pattern and the level of eccDNA expression. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed on the genes associated with the differentially expressed eccDNAs. Five up-regulated and five down-regulated candidate eccDNAs were validated by routine polymerase chain reaction (PCR), TOPO-TA cloning and Sanger sequencing. The nucleotides flanking the eccDNA junctions were analyzed to explore the mechanisms of eccDNA formation.Results: A total of 184,557 eccDNAs was identified. The overall length distribution ranged from 33 to 96,8842 base pairs (bp), with the peak at approximately 360 bp. These eccDNAs mainly originated from 5'-and 3'-untranslated regions (UTRs), and rarely from exons, introns, LINE, or Alu repeat regions. The chromosome distribution, length distribution, and genomic annotation of the eccDNAs were comparable between ESCC samples and matched normal epithelium. Nevertheless, 16,031 eccDNAs were found to be differentially expressed between ESCC and matched normal epithelium, including 10,126 up-regulated eccDNAs and 5,905 down-regulated eccDNAs. GO analysis and KEGG pathway analysis showed enriched in cancer pathways, mitogen-activated protein kinase (MAPK) pathway, GTPase-related activity, and cytoskeleton function. PCR, TOPO-TA cloning, and Sanger sequencing validated the junctional sites of five up-regulated candidate eccDNAs and four other unexpected eccDNAs. A repeat nucleotide pattern between the position flanking the start site and that flanking the end site was detected.Conclusions: This study demonstrated the genome-wide presence of eccDNAs, explored the differential expression of eccDNAs, and revealed the potential mechanisms of eccDNAs in ESCC. This work provides further insights into our understanding of genome plasticity, the role of eccDNAs in ESCC, and may contribute to the development of potential clinical therapies.

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