Pan-cancer analysis of TMEM45A and exploration of its prognostic value and mechanism in gastric cancer.

Cancer is a major category of diseases that need to be addressed urgently, bringing a huge burden to the world. Gastric cancer (GC) is a frequent malignant tumor of the digestive system with the highest incidence and mortality rate among all tumors. The purpose of this study was to explore the mechanism of action of TMEM45A in pan-cancer and gastric cancer. First, GEO and TCGA database were employed to analyze the expression of TMEM45A in GC patients. Then, we determined the association between TMEM45A expression and survival of GC patients using the Kaplan-Meier Plotter database and TCGA database and verified the accuracy of TMEM45A in predicting prognosis. Next, we analyzed the effect of CTHRC expression on TIICs in GC tissues. A prognostic model was constructed using immunomodulatory genes associated with TMEM45A. The specificity and accuracy of the model were verified. TMEM45A expression was markedly higher in GC tissue than in normal tissue. GC patients with TMEM45A overexpression had a poor prognosis. The AUC value of 5-year survival on the ROC curve was 0.705, indicating that TMEM45A is a reliable prognostic factor and can be used as a clinicopathological indicator alone to predict patient prognosis. Three high-risk immunomodulatory genes (CXCR4 and TGFB1) and one low-risk immunomodulatory gene (PDCD1) were obtained using both univariate and multivariate COX methods. These three immunomodulatory molecules were used to construct prognostic models. GC patients with TMEM45A overexpression have a poor prognosis and are associated with immune cell infiltration. Hence, TMEM45A is a fairly reliable independent prognostic marker.

Upregulation of nuclear-enriched abundant transcript 1 confers oxaliplatin resistance to gastric cancer.

The present study aims to investigate the roles of nuclear-enriched abundant transcript 1 (NEAT1) in the regulation of oxaliplatin resistance to gastric cancer (GC). Oxaliplatin-resistant cell lines were constructed using stepwise selection. NEAT1 knockdown and overexpression of NEAT1 were performed. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and colony formation assays were used to evaluate cell proliferation. Propidium iodide (PI) and annexin V staining were used to evaluate cell apoptosis. A dual-luciferase reporter assay was used to evaluate the molecular interactions. Quantitative polymerase chain reaction (qPCR) was used to determine messenger RNA (mRNA) expression. Western blotting was used to determine the protein expression. Kaplan-Meier's analysis was performed to evaluate the relationship between NEAT1 and poor prognosis in GC. NEAT1 was upregulated in oxaliplatin-resistant GC cells and associated with poor prognosis in GC patients. NEAT1 knockdown suppressed oxaliplatin resistance, whereas overexpression of NEAT1 induced oxaliplatin resistance. In addition, the expressions of NEAT1 were negatively associated with miR-26 expressions. Overexpression of NEAT1 attenuated the inhibitory effects of miR-26 on the enhancer of zeste homolog 2 (EZH2). The roles of NEAT1 in the regulation of oxaliplatin resistance to GC are in part by ameliorating the inhibitory effect of miR-26 on EZH2.

Long non-coding RNA HNF1A-AS1 mediated repression of miR-34a/SIRT1/p53 feedback loop promotes the metastatic progression of colon cancer by functioning as a competing endogenous RNA.

In recent years, accumulating evidence indicates that long noncoding RNAs (lncRNAs) have emerged as powerful influence factors in the progression of multiple malignancies. Dysregulation of lncRNA HNF1A-antisense 1 (HNF1A-AS1) has been reported in many types of human cancers, and studies on HNF1A-AS1 function in cancers revealed that HNF1A-AS1could act as either oncogene or tumor suppressor. Nevertheless, the functional involvement of HNF1A-AS1 in colon cancer remains unknown. In this study, we reported that HNF1A-AS1 was frequently upregulated in colon cancer tissues and associated with poor prognosis. Upregulated HNF1A-AS1 promoted colon cancer cell viability, migration and invasion both in vitro and in vivo. HNF1A-AS1 silencing impaired tumor growth and metastasis in xenograft model assay. Moreover, HNF1A-AS1 functioned as an oncogene in metastasis of colon cancer in part through serving as a competing endogenous RNA to modulate miRNA-34a expression, subsequently with repression of miR-34a/SIRT1/p53 feedback loop and activation of canonical Wnt signaling pathway. Our results demonstrated that HNF1A-AS1 mediated the metastatic progression of colon cancer in part through miR-34a/p53 signaling axis, and established its candidacy as a new prognostic biomarker and a potential novel therapeutic target.

Long non-coding ribonucleic acid zinc finger antisense 1 promotes the progression of colonic cancer by modulating ZEB1 expression.

BACKGROUND AND AIM: Long non-coding RNA zinc finger antisense 1 (ZFAS1) is frequently amplified in hepatocellular carcinoma and promotes metastasis by increasing zinc finger E-box binding homeobox 1 (ZEB1), which can potentiate the progression of epithelial-to-mesenchymal transition (EMT). However, the expression pattern and role of ZFAS1 in colonic cancer remains unknown. The present study aimed to investigate the role of ZFAS1 and its clinical significance in colonic cancer. METHODS: Paired clinical colonic cancer tissue samples and clinicopathologic characteristics of 73 patients were analyzed. Quantitative real-time polymerase chain reaction analysis was used to evaluate expression levels of ZFAS1 in colonic cancer tissues, cell lines, and plasma. ZEB1 and EMT-related markers expression levels also were explored. Cell biology assays were used to explore the biologic consequences of ZFAS1 in regulating cell proliferation and invasion, as well as the roles in regulating EMT. RESULTS: Zinc finger antisense 1 was up-regulated in colonic cancer tissues compared with adjacent mucosa (P < 0.01), and its expression level was significantly correlated with TNM stage, vascular invasion, and lymph node metastasis (P < 0.05). ZFAS1 and ZEB1 were also increased in patients' plasma. Moreover, ZFAS1 promoted proliferation, invasion, and impeded apoptosis. Knockdown of ZFAS1 decreased expression of ZEB1 and increased the epithelial markers E-cadherin, ZO-1 while decreasing mesenchymal markers vimentin and N-cadherin. CONCLUSIONS: Long non-coding RNA ZFAS1 may function as an oncogene by modulating ZEB1 to induce EMT. Manipulation of ZFAS1 level may be a novel approach to suppress colonic cancer progression. In addition, ZFAS1 in plasma has the potential to be a diagnostic biomarker of colonic cancer.

Linc00152 Functions as a Competing Endogenous RNA to Confer Oxaliplatin Resistance and Holds Prognostic Values in Colon Cancer.

Long noncoding RNAs act as crucial regulators in plenty of human cancers, yet their potential roles and molecular mechanisms in chemoresistance are poorly understood. This study showed that a novel lncRNA, long intergenic noncoding RNA 152 (Linc00152 ), promoted tumor progression and conferred resistance to oxaliplatin (L-OHP)-induced apoptosis in vitro and in vivo. It antagonized chemosensitivity through acting as a competing endogenous RNA to modulate the expression of miR-193a-3p, and then erb-b2 receptor tyrosine kinase 4 (ERBB4). Knockdown of ERBB4 in colon cancer cells decreased AKT phosphorylation, which resulted in decreased L-OHP resistance. Consistent with above findings, the specific AKT signaling inhibitor and activator were used, respectively, which demonstrated that Linc00152 contributed to L-OHP resistance at least partly through activating AKT pathway. Further studies indicated that Linc00152 was increased and appeared to be an independent prognostic factor for decreased survival and increased disease recurrence in stage II and III colon cancer patients undergoing L-OHP-based chemotherapy after surgery. Collectively, our findings established Linc00152 as a candidate prognostic indicator of outcome and drug responsiveness in colon cancer patients, and the involvement of competing endogenous RNAs mechanism in Linc00152/miR-193a-3p/ERBB4/AKT signaling axis may provide a novel choice in the investigation of drug resistance.

Elevated expression of Thoc1 is associated with aggressive phenotype and poor prognosis in colorectal cancer.

The THO complex 1 (Thoc1) is a nuclear matrix protein playing vital roles in transcription elongation and mRNA export. Recently, aberrant expression of Thoc1 has been reported in an increasing array of tumor types. However, the clinical significance of Thoc1 expression in colorectal cancer (CRC) is still unknown. The present study aimed to characterize the expression of Thoc1 in human CRC and evaluate its clinical significance. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting analyses showed that the mRNA and protein expression of Thoc1 in CRC specimens was significantly higher than that in adjacent normal colon mucosae. Immunohistochemistry (IHC) was conducted to characterize the expression pattern of Thoc1 in 185 archived paraffin-embedded CRC specimens. Statistical analyses revealed that high levels of Thoc1 expression were associated with the clinical stages and tumor differentiation. CRC patients with high levels of Thoc1 expression had poorer overall-survival and disease-free survival, whereas those with lower levels of Thoc1 expression survived longer. Furthermore, multivariate Cox regression analyses demonstrated that Thoc1 expression remained an independent prognostic factor for increased disease recurrence and decreased survival. Our results suggest for the first time that Thoc1 is involved in the development and progression of CRC, and elevated expression of Thoc1 is associated with aggressive phenotype and poor prognosis in CRC. These findings may prove to be clinically useful for developing a new therapeutic target of CRC treatment.