Dandan Yin

Long noncoding RNA PVT1 indicates a poor prognosis of gastric cancer and promotes cell proliferation through epigenetically regulating p15 and p16

BackgroundMounting evidence indicates that long noncoding RNAs (lncRNAs) could play a pivotal role in cancer biology. However, the overall biological role and clinical significance of PVT1 in gastric carcinogenesis remains largely unknown.MethodsExpression of PVT1 was analyzed in 80 GC tissues and cell lines by qRT-PCR. The effect of PVT1 on proliferation was evaluated by MTT and colony formation assays, and cell apoptosis was evaluated by Flow-cytometric analysis. GC cells transfected with shPVT1 were injected into nude mice to study the effect of PVT1 on tumorigenesis in vivo. RIP was performed to confirm the interaction between PVT1 and EZH2. ChIP was used to study the promoter region of related genes.ResultsThe higher expression of PVT1 was significantly correlated with deeper invasion depth and advanced TNM stage. Multivariate analyses revealed that PVT1 expression served as an independent predictor for overall survival (p = 0.031). Further experiments demonstrated that PVT1 knockdown significantly inhibited the proliferation both in vitro and in vivo. Importantly, we also showed that PVT1 played a key role in G1 arrest. Moreover, we further confirmed that PVT1 was associated with enhancer of zeste homolog 2 (EZH2) and that this association was required for the repression of p15 and p16. To our knowledge, this is the first report showed that the role and the mechanism of PVT1 in the progression of gastric cancer.ConclusionsTogether, these results suggest that lncRNA PVT1 may serve as a candidate prognostic biomarker and target for new therapies in human gastric cancer.

Low expression of long noncoding RNA PANDAR predicts a poor prognosis of non-small cell lung cancer and affects cell apoptosis by regulating Bcl-2.

Recently, a novel class of transcripts, long noncoding RNAs (lncRNAs), is involved in diseases including cancer. Here, we investigated the the role of lncRNA PANDAR in the progression of non-small cell lung carcinoma (NSCLC). PANDAR, interacting with NF-YA, was generally downregulated in NSCLC tissues. In a cohort of 140 NSCLC patients, decreased PANDAR expression was negatively correlated with greater tumor size (P<0.001) and advanced TNM stage (P=0.002). Moreover, PANDAR could serve as an independent predictor for overall survival in NSCLC (P=0.015). Further experiments demonstrated that PANDAR expression was induced by p53, and chromatin immunoprecipitation (ChIP) assays confirmed that PANDAR was a direct transcriptional target of p53 in NSCLC cells. PANDAR overexpression significantly repressed the proliferation in vitro and in vivo. We also showed that PANDAR-mediated growth regulation is in part due to the transcriptional modulation of Bcl-2 by interacting with NF-YA, thus affecting NSCLC cell apoptosis. To our knowledge, this is the first report which showed the role of PANDAR in the progression of NSCLC. The p53/PANDAR/NF-YA/Bcl-2 interaction might serve as targets for NSCLC diagnosis and therapy.

Decreased expression of long noncoding RNA MEG3 affects cell proliferation and predicts a poor prognosis in patients with colorectal cancer

Colorectal cancer (CRC) remains an important public health problem in the world. Long noncoding RNA (lncRNA) is an RNA molecular that is longer than 200 nucleotides and cannot be translated into a protein. Recent studies have shown that lncRNAs play important roles in carcinogenesis and cancer metastasis. The aim of this study was to evaluate the expression and biological role of lncRNA maternally expressed gene 3 (MEG3) in colorectal cancer. Quantitative real-time-PCR (qRT-PCR) was performed to investigate the expression of MEG3 in tumor tissues and corresponding nontumor colorectal tissues from 62 patients. The lower expression of MEG3 was remarkably correlated with low histological grade, deep tumor invasion, and advanced tumor node metastasis (TNM) stage. Multivariate analyses revealed that MEG3 expression served as an independent predictor for overall survival. Further experiments revealed that overexpressed MEG3 significantly inhibited CRC cell proliferation both in vitro and in vivo. In conclusion, our study demonstrated that MEG3 is involved in the development and progression of colorectal cancer by regulating cell proliferation and shows that MEG3 may be a potential diagnostic and prognostic target in patients with colorectal cancer.

Increased expression of long noncoding RNA TUG1 predicts a poor prognosis of gastric cancer and regulates cell proliferation by epigenetically silencing of p57

Recent evidence highlights long noncoding RNAs (lncRNAs) as crucial regulators of cancer biology that contribute to tumorigenesis. LncRNA TUG1 was initially detected in a genomic screen for genes upregulated in response to taurine treatment in developing mouse retinal cells. Our previous study showed that TUG1 could affect cell proliferation through epigenetically regulating HOXB7 in human non-small cell lung cancer. However, the clinical significance and potential role of TUG1 in GC remains unclear. In this study, we found that TUG1 is significantly increased and is correlated with outcomes in gastric cancer (GC). Further experiments revealed that knockdown of TUG1 repressed GC proliferation both in vitro and in vivo. Mechanistic investigations showed that TUG1 has a key role in G0/G1 arrest. We further demonstrated that TUG1 was associated with PRC2 and that this association was required for epigenetic repression of cyclin-dependent protein kinase inhibitors, including p15, p16, p21, p27 and p57, thus contributing to the regulation of GC cell cycle and proliferation. Together, our results suggest that TUG1, as a regulator of proliferation, may serve as a candidate prognostic biomarker and target for new therapies in human GC.

Downregulation of Long Noncoding RNA Meg3 Affects Insulin Synthesis and Secretion in Mouse Pancreatic Beta Cells.

Increasing evidence indicates that long noncoding RNAs (lncRNAs) are involved in diverse biological process. Mouse maternal expressed gene 3 (Meg3) is an imprinted gene and essential for development. Here, we explored the relationship between Meg3 and the function of mouse beta cells in vitro and in vivo. Real‐time PCR analyses revealed that Meg3 was more abundantly expressed in Balb/c mouse islets than exocrine glands. Moreover, the expression of Meg3 in islets was decreased in T1DM (NOD female mice) and T2DM (db/db mice) models. Meg3 expression was modulated dynamically by glucose in Min6 cells and isolated mouse islets. The function role of Meg3 was investigated in Min6 cells and normal mouse by knockdown of Meg3 using small interfering RNA. After suppression of Meg3 expression in vitro, insulin synthesis and secretion were impaired and the rate of beta cells apoptosis was increased. Moreover, knockdown of Meg3 in vivo led to the impaired glucose tolerance and decreased insulin secretion, consisted with the reduction of insulin positive cells areas by immunochemistry assays. Notably, islets from Meg3 interference groups showed significant decrease of Pdx‐1 and MafA expression in mRNA and protein levels. These results indicate that Meg3 may function as a new regulator of maintaining beta cells identity via affecting insulin production and cell apoptosis. J. Cell. Physiol. 231: 852–862, 2016.

H3K27 acetylation activated-long non-coding RNA CCAT1 affects cell proliferation and migration by regulating SPRY4 and HOXB13 expression in esophageal squamous cell carcinoma.

Abstract Recently, long non-coding RNAs (lncRNAs) have been shown to have important regulatory roles in human cancer biology. In our study, we found that lncRNA CCAT1, whose expression is significantly increased and is correlated with outcomes in Esophageal Squamous Cell Carcinoma (ESCC). Consecutive experiments confirmed that H3K27-acetylation could activate expression of colon cancer associated transcript-1 (CCAT1). Further experiments revealed that CCAT1 knockdown significantly repressed the proliferation and migration both in vitro and in vivo. RNA-seq analysis revealed that CCAT1 knockdown preferentially affected genes that are linked to cell proliferation, cell migration and cell adhesion. Mechanistic investigations found that CCAT1 could serve as a scaffold for two distinct epigenetic modification complexes (5΄ domain of CCAT1 binding Polycomb Repressive Complex 2 (PRC2) while 3΄ domain of CCAT1 binding SUV39H1) and modulate the histone methylation of promoter of SPRY4 (sprouty RTK signaling antagonist 4) in nucleus. In cytoplasm, CCAT1 regulates HOXB13 as a molecular decoy for miR-7, a microRNA that targets both CCAT1 and HOXB13, thus facilitating cell growth and migration. Together, our data demonstrated the important roles of CCAT1 in ESCC oncogenesis and might serve as targets for ESCC diagnosis and therapy.

Downregulation of lncRNA TUG1 Affects Apoptosis and Insulin Secretion in Mouse Pancreatic β Cells

Background: Increasing evidence indicates that long noncoding RNAs (IncRNAs) perform specific biological functions in diverse processes. Recent studies have reported that IncRNAs may be involved in β cell function. The aim of this study was to characterize the role of IncRNA TUG1 in mouse pancreatic β cell functioning both in vitro and in vivo. Methods: qRT-PCR analyses were performed to detect the expression of lncRNA TUG1 in different tissues. RNAi, MTT, TUNEL and Annexin V-FITC assays and western blot, GSIS, ELISA and immunochemistry analyses were performed to detect the effect of lncRNA TUG1 on cell apoptosis and insulin secretion in vitro and in vivo. Results: lncRNA TUG1 was highly expressed in pancreatic tissue compared with other organ tissues, and expression was dynamically regulated by glucose in Nit-1 cells. Knockdown of lncRNA TUG1 expression resulted in an increased apoptosis ratio and decreased insulin secretion in β cells both in vitro and in vivo . Immunochemistry analyses suggested decreased relative islet area after treatment with lncRNA TUG1 siRNA. Conclusion: Downregulation of lncRNA TUG1 expression affected apoptosis and insulin secretion in pancreatic β cells in vitro and in vivo. lncRNA TUG1 may represent a factor that regulates the function of pancreatic β cells.

Low expression of long noncoding RNA CASC2 indicates a poor prognosis and regulates cell proliferation in non-small cell lung cancer.

Recently, long noncoding RNAs (lncRNAs) have been shown to have important regulatory roles in human cancer biology. The aim of this study was to evaluate the expression and biological role of lncRNA CASC2 in non-small cell lung cancer (NSCLC). By bioinformatics analysis, we found that CASC2 was significantly decreased in NSCLC. qRT-PCR was performed to investigate the expression of CASC2 in tumor tissues and corresponding non-tumor NSCLC tissues from 76 patients. The lower expression of CASC2 was remarkably correlated with advanced TNM stage and tumor size. Multivariate analyses found that CASC2 expression served as an independent predictor for overall survival of NSCLC. Moreover, overexpression of CASC2 significantly inhibited NSCLC cell proliferation both in vitro and in vivo. In conclusion, our study demonstrated that CASC2 is involved in the development and progression of NSCLC and shows that CASC2 may be a potential diagnostic and target for new therapies in patients with NSCLC.

c-Myc-regulated long non-coding RNA H19 indicates a poor prognosis and affects cell proliferation in non-small-cell lung cancer.

Recently, long non-coding RNAs (lncRNAs) have been shown to play important roles in human cancer biology. The purpose of this study was to assess the biological role of lncRNA H19 in non-small-cell lung cancer (NSCLC). Quantitative reverse transcription PCR (qRT-PCR) was used to detect the expression of H19 in tumor tissues and corresponding non-tumor NSCLC tissues from 70 patients. The higher expression of H19 was positively correlated with advanced tumor–node–metastasis (TNM) stage and tumor size. Multivariate analyses found that H19 expression could serve as an independent prognostic factor for overall survival of NSCLC. Moreover, chromatin immunoprecipitation (ChIP) assays revealed that H19 was a direct transcriptional target of c-Myc. And, knockdown of H19 significantly inhibited NSCLC cell proliferation both in vitro and in vivo. In conclusion, our study demonstrated that H19 is involved in the oncogenesis of NSCLC, and H19 may be a potential diagnostic and target for new therapies in patients with NSCLC.

Long noncoding RNA BLACAT1 indicates a poor prognosis of colorectal cancer and affects cell proliferation by epigenetically silencing of p15

Recently, a novel class of transcripts, long noncoding RNAs (lncRNAs), is being identified at a rapid pace. These RNAs have critical roles in diverse biological processes, including tumorigenesis. One of them, BLACAT1, a cancer-associated long noncoding RNA, exerts regulatory functions in various biological processes in cancer cells, however, the role of BLACAT1 in colon cancer remains unclear. Our experiments showed that increased BLACAT1 was an independent unfavorable prognostic indicator for colorectal cancer, and revealed that BLACAT1 knockdown significantly repressed proliferation, both in vitro and in vivo. Mechanistic investigations demonstrated that BLACAT1 had a key role in G1/G0 arrest, and showed that BLACAT1 can repress p15 expression by binding to EZH2, thus contributing to the regulation of CRC cell cycle and proliferation. Our results suggest that BLACAT1, as a cell cycle regulator, may serve as a potential target for colon cancer prevention and treatment in human CRC.