Expression and clinical significance of the long non-coding RNA PVT1 in human gastric cancer

Liu

Experimental and Therapeutic Medicine

et al. 2017

Abstract. Kanglaite (KLT) was shown to alleviate the development of multidrug resistance (MDR) clinically. The purpose of this study is to examine the mechanism of KLT for chemotherapy resistance in gastric cancer cells involving the regulation of MDR-related proteins. The cisplatin-resistant BGC823/DPP and SGC7901/DDP cells were treated with 1, 2.5 and 5 µl/ml of KLT for 24, 36 and 48 h. Cell Counting Kit-8 (CCK-8) assay and flow cytometry were performed to detect the cell viability and cell apoptosis, respectively. The expression of MDR1 and multidrug resistance associated protein 1 (MRP1) were examined by quantitative PCR and western blotting in BGC823/DPP cells and SGC7901/DDP cells treated with KLT. The effect of KLT on the expression of PVT1 was investigated. PVT1-overexpression vector was constructed and transfected into BGC823/DPP cells and SGC7901/DDP cells which were treated with KLT. KLT inhibited the cell viability and promoted the cell apoptosis of BGC823/DPP cells and SGC7901/DDP cells in a concentration-dependent manner. KLT suppressed the expression of MDR1 and MRP1 and the level of PVT1. PVT1 overexpression reversed the increased percentage of apoptotic cells induced by KLT. Finally, we found that PVT1 overexpression also abrogated the effect of KLT on the mRNA level and protein level of MDR1 and MRP1 in BGC823/DPP and SGC7901/DDP cells. KLT inhibited the expression of MDR1 and MRP1 via suppressing the expression of PVT1, which suggested the potential mechanism of KLT involving in MDR in gastric cancer.

Section: Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Kanglaite inhibits the expression of drug resistance genes through suppressing PVT1 in cisplatin-resistant gastric cancer cells

Liu

Experimental and Therapeutic Medicine

et al. 2017

“…Fifteen percent to 18% of somatic promoters mapped to noncoding RNAs, including HOTAIR and PVT1, previously associated with gastric cancer (Supplementary Table S3; refs. 52,53). Additional analyses at increasing thresholds of stringency (FC from 1.5 to 2 and FDR from 0.1 to 0.001) yielded similar results, supporting the robustness of this analysis ( Supplementary Fig.…”

Section: Identifying Epigenomic Promoter Alterations In Gastric Cancersupporting

confidence: 74%

Epigenomic Promoter Alterations Amplify Gene Isoform and Immunogenic Diversity in Gastric Adenocarcinoma

et al. 2017

Promoter elements play important roles in isoform and cell type-specific expression. We surveyed the epigenomic promoter landscape of gastric adenocarcinoma, analyzing 110 chromatin profiles (H3K4me3, H3K4me1, H3K27ac) of primary gastric cancers, gastric cancer lines, and nonmalignant gastric tissues. We identified nearly 2,000 promoter alterations (somatic promoters), many deregulated in various epithelial malignancies and mapping frequently to alternative promoters within the same gene, generating potential pro-oncogenic isoforms (RASA3). Somatic promoterassociated N-terminal peptides displaying relative depletion in tumors exhibited high-affinity MHC binding predictions and elicited potent T-cell responses in vitro, suggesting a mechanism for reducing tumor antigenicity. In multiple patient cohorts, gastric cancers with high somatic promoter usage also displayed reduced T-cell cytolytic marker expression. Somatic promoters are enriched in PRC2 occupancy, display sensitivity to EZH2 therapeutic inhibition, and are associated with novel cancer-associated transcripts. By generating tumor-specific isoforms and decreasing tumor antigenicity, epigenomic promoter alterations may thus drive intrinsic tumorigenesis and also allow nascent cancers to evade host immunity. SIGNIFICANCE:We apply epigenomic profiling to demarcate the promoter landscape of gastric cancer. Many tumor-specific promoters activate different promoters in the same gene, some generating pro-oncogenic isoforms. Tumor-specific promoters also reduce tumor antigenicity by causing relative depletion of immunogenic peptides, contributing to cancer immunoediting and allowing tumors to evade host immune attack. Cancer Discov; 7(6);

International Journal of Oncology

“…The ceRNA network we built reveals an unknown ceRNA regulatory network in GC. Recent study also identified that lncRNA interactions with miRNA and mRNA might act as potential diagnosis and prognosis biomarkers in cancer, such as H19, PVT1, HOTAIR, UCA1 and TINCR (7,(48)(49)(50)(51). In our ceRNA network, we also found these key lncRNAs.…”

Section: Discussionsupporting

confidence: 57%

Integrated analysis of long non-coding RNA competing interactions reveals the potential role in progression of human gastric cancer

Liang

Yao

et al. 2016

112

Abstract. Abnormal expression of long non-coding RNAs (lncRNAs) have been shown to play an important role in tumor biology. The Cancer Genome Atlas (TCGA) platform is a large sample sequencing database of lncRNAs, and further analysis of the associations between these data and patients' clinical related information can provide new approaches to find the functions of lncRNA. In the present study, 361 RNA sequencing profiles of gastric cancer (GC) patients were selected from TCGA. Then, we constructed the lncRNA-miRNA-mRNA competitive endogenous RNA (ceRNA) network of GC. There were 25 GC specific lncRNAs (fold change >2, p<0.05) identified, 19 of them were included in ceRNA network. Subsequently, we selected these 19 key lncRNAs and analyzed the correlations with clinical features and overall survival, 14 of them were discriminatively expressed with tumor size, tumor grade, TNM stage and lymphatic metastasis (p<0.05). In addition, eight lncRNAs (RPLP0P2, FOXD2-AS1, H19, TINCR, SLC26A4-AS1, SMIM10L2A, SMIM10L2B and SNORD116-4) were found to be significantly associated with overall survival (log-rank p<0.05). Finally, two key lncRNAs HOTAIR and UCA1 were selected for validation of their expression levels in 82 newly diagnosed GC patients by qRT-PCR. Results showed that the fold changes between TCGA and qRT-PCR were 100% in agreement. In addition, we also found that HOTAIR was significantly correlated with tumor size and lymphatic metastasis (p<0.05), and UCA1 was significantly correlated with tumor size, TNM stage and lymphatic metastasis (p<0.05).The clinical relevance of the two lncRNAs and the bioinformatics analysis results were almost the same. Overall, our study showed the GC specific lncRNAs expression patterns and a ceRNA network in GC. Clinical features related to GC specific lncRNAs also suggested these lncRNAs are worthwhile for further study as novel candidate biomarkers for the clinical diagnosis of GC and potential indicators for prognosis. IntroductionNoncoding RNAs (ncRNAs) are transcripts that have no ability of coding proteins, which widely exit in high eukaryotics. According to their characteristics, ncRNAs can be divided into several subtypes including transfer RNA, small nucleolar RNA (snoRNA), ribosomal RNA (rRNA), microRNA (miRNA) and long non-coding RNA (lncRNA). The amount of the ncRNAs transcripts is >98% of the whole genome transcripts and have been suggested to represent transcriptional noise (1). However, more and more evidence indicates that transcriptional output of genome is far more complex than predicted, and suggests new paradigms of ncRNA regulation (2).Recent studies suggest that the ncRNAs may play important biological roles in transcriptional regulation, cellular development, formation of chromosome and RNA modification (3). Based on the transcript size, ncRNAs are grouped into small ncRNAs (<200 bp) and long ncRNAs (>200 bp, up to 100 kb). lncRNA is the functional end-product, and the level of lncRNA expression correlates directly with the level of the active molecule. Thus, ...