H. Bo

AFAP1-AS1, a long noncoding RNA upregulated in lung cancer and promotes invasion and metastasis

Long noncoding RNAs (lncRNAs) have emerged as a major regulator of cancer. Significant fraction of lncRNAs is represented on widely used microarray platforms; however, many of which have no known function. To discover novel lung cancer-related lncRNAs, we analyzed the lncRNA expression patterns in five sets of previously published lung cancer gene expression profile data that were represented on Affymetrix HG-U133 Plus 2.0 array, and identified dysregulated lncRNAs in lung cancer. One lncRNA, actin filament associated protein 1 antisense RNA1 (AFAP1-AS1), was the most significantly upregulated in lung cancer and associated with poor prognosis. In vitro experiments demonstrated that AFAP1-AS1 knockdown significantly inhibited the cell invasive and migration capability in lung cancer cells. AFAP1-AS1 knockdown also increased the expression of its antisense protein coding gene, actin filament associated protein 1 (AFAP1), and affected the expression levels of several small GTPase family members and molecules in the actin cytokeratin signaling pathway, which suggested that AFAP1-AS1 promoted cancer cell metastasis via regulation of actin filament integrity. Our findings extend the number of noncoding RNAs functionally implicated in lung cancer progression and highlight the role of AFAP1-AS1 as potential prognostic biomarker and therapeutic target of lung cancer.

Epstein-Barr virus-encoded miR-BART6-3p inhibits cancer cell metastasis and invasion by targeting long non-coding RNA LOC553103

Epstein-Barr virus (EBV) infection is causatively related to a variety of human cancers, including nasopharyngeal carcinoma (NPC) and gastric cancer (GC). EBV encodes 44 mature miRNAs, a number of which have been proven to promote carcinogenesis by targeting host genes or self-viral genes. However, in this study, we found that an EBV-encoded microRNA, termed EBV-miR-BART6-3p, inhibited EBV-associated cancer cell migration and invasion including NPC and GC by reversing the epithelial–mesenchymal transition (EMT) process. Using microarray analysis, we identified and validated that a novel long non-coding RNA (lncRNA) LOC553103 was downregulated by EBV-miR-BART6-3p, and LOC553103 knockdown by specific siRNAs phenocopied the effect of EBV-miR-BART6-3p, while LOC553103 overexpression promoted cancer cell migration and invasion to facilitate EMT. In conclusion, we determined that EBV-miR-BART6-3p, a microRNA encoded by oncogenic EBV, inhibited EBV-associated cancer cell migration and invasion by targeting and downregulating a novel lncRNA LOC553103. Thus, our study presents an unreported mechanism underlying EBV infection in EBV-associated cancer carcinogenesis, and provides a potential novel diagnosis and treatment biomarker for NPC and other EBV-related cancers.

Regulation network and expression profiles of Epstein-Barr virus-encoded microRNAs and their potential target host genes in nasopharyngeal carcinomas

Epstein-Barr virus (EBV) is associated with nasopharyngeal carcinoma (NPC) tumorigenesis. However, the mechanism(s) connecting EBV infection and NPC remain unclear. Recently, a new class of EBV microRNAs (miRNAs) has been described. To determine how EBV miRNAs control the expression of host genes, and to understand their potential role in NPC tumorigenesis, we profiled the expression of 44 mature EBV miRNAs and potential host genes in NPC and non-tumor nasopharyngeal epithelial tissues. We found that 40 EBV miRNAs from the BART transcript were highly expressed in NPC. Analysis of potential BART miRNA target genes revealed that 3140 genes and several important pathways might be involved in the carcinogenesis of NPC. A total of 105 genes with potential EBV miRNA binding sites were significantly downregulated, suggesting that EBV miRNAs may regulate these genes and contribute to NPC carcinogenesis. An EBV miRNA and host gene regulation network was generated to provide useful clues for validating of EBV miRNA functions in NPC tumorigenesis.

Cloning and functional characterization of a novel long non-coding RNA gene associated with hepatocellular Carcinoma

Recently, we sequenced the transcriptomes of a hepatocellular carcinoma biopsy and a normal liver tissue using the RNA-Sequencing(RNA-Seq) strategy based on the Next Generation Sequencing(NGS) technique, and identified several adjacent high RNA-Seq signal peaks on chromosome 11q13.1 in the hepatocellular carcinoma biopsy, while not in the normal control tissue. In this chromosome region, there is no characterized genes have been identified, implying that these RNA-Seq peaks may represent one or more novel genes. Further study was confirmed that these RNA-Seq peaks were transcribed by one novel gene. Through cloning the full length of this novel gene, we found that this novel gene transcribed many splicing isoforms, and the longest isoform is 3 562 bp. Then we deposited twelve representative RNA isoforms into the GenBank database of the National Center for Biotechnology Information(NCBI), and created the GenBank IDs from KC136297 to KC136308 for these isoforms. None significant open reading fragment(ORF) was found in any transcripts of this novel gene, implying that this gene may encodes long non-coding RNAs(lncRNAs). To further elucidate the potential transcriptional regulation mechanism of this lncRNA gene, we predicted the promoter from the upstream sequence of the lncRNA gene using bioinformatic tools, and found that there is one potential promoter in-719 to-469 bp from the transcript start site of the lncRNA gene, and there are seven Sp1, one STAT5 and one EGR1 transcription factor binding sites in the promoter region. The molecular mechanisms of the lncRNA gene in carcinogenesis and progression of hepatocellular carcinoma are worthful for further investigation.

Inhibition of REDD1 sensitizes bladder urothelial carcinoma to paclitaxel by inhibiting autophagy

Purpose: Regulated in development and DNA damage response-1 (REDD1) is a stress-related protein and is involved in the progression of cancer. The role and regulatory mechanism of REDD1 in bladder urothelial carcinoma (BUC), however, is yet unidentified. Experimental Design: The expression of REDD1 in BUC was detected by Western blot analysis and immunohistochemistry (IHC). The correlation between REDD1 expression and clinical features in patients with BUC were assessed. The effects of REDD1 on cellular proliferation, apoptosis, autophagy, and paclitaxel sensitivity were determined both in vitro and in vivo. Then the targeted-regulating mechanism of REDD1 by miRNAs was explored. Results: Here the significant increase of REDD1 expression is detected in BUC tissue, and REDD1 is first reported as an independent prognostic factor in patients with BUC. Silencing REDD1 expression in T24 and EJ cells decreased cell proliferation, increased apoptosis, and decreased autophagy, whereas the ectopic expression of REDD1 in RT4 and BIU87 cells had the opposite effect. In addition, the REDD1-mediated proliferation, apoptosis, and autophagy are found to be negatively regulated by miR-22 in vitro, which intensify the paclitaxel sensitivity via inhibition of the well-acknowledged REDD1–EEF2K–autophagy axis. AKT/mTOR signaling initially activated or inhibited in response to silencing or enhancing REDD1 expression and then recovered rapidly. Finally, the inhibited REDD1 expression by either RNAi or miR-22 sensitizes BUC tumor cells to paclitaxel in a subcutaneous transplant carcinoma model in vivo. Conclusions: REDD1 is confirmed as an oncogene in BUC, and antagonizing REDD1 could be a potential therapeutic strategy to sensitize BUC cells to paclitaxel. Clin Cancer Res; 24(2); 445–59. ©2017 AACR.

SPAG5 promotes proliferation and suppresses apoptosis in bladder urothelial carcinoma by upregulating Wnt3 via activating the AKT/mTOR pathway and predicts poorer survival

Sperm-associated antigen 5 (SPAG5) is involved in various biological processes. However, the roles of SPAG5 in bladder urothelial carcinoma (BUC) are unknown. This study showed that upregulation of SPAG5 was detected frequently in primary BUC tissues, and was associated with significantly worse survival among the 112 patients that underwent radical cystectomy (RC). Up and downregulating the expression of SPAG5 enhanced or inhibited, respectively, the proliferation of BUC cells in vitro and in vivo, and suppressed or enhanced, respectively, apoptosis in vitro and in vivo. Moreover, SPAG5 increased the resistance of BUC cells to chemotherapy-induced apoptosis. Mechanistic investigations showed that SPAG5 promotes proliferation and suppresses apoptosis in BUC at least partially via upregulating Wnt3 through activating the AKT/mTOR signaling pathway. The importance of the SPAG5/AKT-mTOR/Wnt3 axis identified in BUC cell models was confirmed via immunohistochemical analysis of a cohort of human BUC specimens that underwent RC. Collectively, our data suggested that in patients with BUC who underwent RC, high SPAG5 expression is associated with poor survival. In addition, targeting SPAG5 might represent a novel therapeutic strategy to improve the survival of patients with BUC.