lncRNA RMST suppresses the progression of colorectal cancer by competitively binding to miR-27a-3p/RXRα axis and inactivating Wnt signaling pathway.

Colorectal cancer (CRC) ranks the 3rd in cancer types globally. Long noncoding RNAs (lncRNAs) are related to the initiation and progression of CRC. The current study plans to reveal the action of rhabdomyosarcoma 2-associated transcript (RMST) in CRC. The results show that RMST is downregulated in CRC specimens and cell lines relative to normal specimens and a fetal normal colon cell line (FHC), respectively. Elevation of RMST represses cell proliferation and colony formation and induces cell apoptosis in CRC cells. Bioinformatic analysis reveals a binding site in RMST for miR-27a-3p. The direct association between RMST and miR-27a-3p is confirmed by dual luciferase reporter assay, RNA pull-down assay, and real time-quantitative polymerase chain reaction (RT-qPCR). miR-27a-3p is upregulated in CRC tumor specimens relative to normal specimens, and there is a negative correlation between RMST and miR-27a-3p in CRC tumor specimens. In addition, the effects of RMST overexpression are weakened by the elevation of miR-27a-3p. RMST and retinoid X receptor (RXRα) share the same complementary site with miR-27a-3p. The direct association between RXRα and miR-27a-3p is confirmed by RNA pull-down assay, RT-qPCR and western blot analysis. Overexpression of RMST induces RXRα expression and inactivates the Wnt signaling pathway by decreasing ß-catenin levels in CRC cells. Collectively, our findings reveal a pivotal role of RMST in regulating miR-27a-3p/RXRα axis and counteracting Wnt signaling pathway during the progression of CRC.

LncRNA AGAP2-AS1 Promotes Cancer Cell Proliferation, Migration and Invasion in Colon Cancer by Forming a Negative Feedback Loop with LINC-PINT.

INTRODUCTION: It has been reported that lncRNA AGAP2-AS1 promotes the development of gastric cancer, lung cancer and breast cancer. This study aimed to investigate the role of AGAP2-AS1 in colon cancer. METHODS: A total of 66 patients with colon cancer were enrolled. RT-qPCR was performed to detect the differential expression of AGAP2-AS1 in tumor tissues and adjacent normal tissues. To test the interaction between AGAP2-AS1 and LINC-PINT in colon cancer, overexpression vector or inhibitor of AGAP2-AS1 and LINC-PINT were transfected into RKO and HCT 116 cells. CCK-8 assay was used to detect cell proliferation. Transwell assays were performed to evaluate cell migration and invasion. The expression of p-LATS1, p-YAP and nuclear YAP were detected by Western blot and immunofluorescence. RESULTS: The expression of AGAP2-AS1 was upregulated in colon cancer tissues compared with that in adjacent normal tissues, and the expression of AGAP2-AS1 in colon cancer tissues was not significantly affected by tumor stages. In addition, we found that the expression of LINC-PINT was downregulated in colon cancer tissues compared with that in adjacent normal tissues and had a reverse correlation with the expression of AGAP2-AS1 in colon cancer tissues. Moreover, overexpression of AGAP2-AS1 downregulated the expression of LINC-PINT, and overexpression of LINC-PINT also altered the expression of AGAP2-AS1 in colon cancer cells. Inhibition of AGAP2-AS1 upregulated the expression of LINC-PINT, and inhibition of LINC-PINT promoted the expression levels of AGAP2-AS1 in colon cancer cells. Furthermore, overexpression of AGAP2-AS1 could increase the proliferation, invasion and migration of colon cancer cells, while overexpression of LINC-PINT could attenuate the effects of overexpression of AGAP2-AS1 on the proliferation, migration and invasion of colon cancer cells. We also found that AGAP2-AS1 promoted colon cancer cell proliferation, migration and invasion through the Hippo signaling. CONCLUSION: Upregulated expression of AGAP2-AS1 promoted proliferation, invasion and migration in colon cancer by forming a negative feedback loop with LINC-PINT.

Exploration of Potential Roles of m6A Regulators in Colorectal Cancer Prognosis.

Colorectal cancer (CRC) represents one of the most common malignancies with high morbidity worldwide. RNA methylation (m6A) has been considered to tremendously contribute to cancer initiation and progression since its first discovery. In this study, we comprehensively analyzed associations between mRNA expressions of m6A regulators and CRC tumor samples' epidemiologic information from the Cancer Genome Atlas (TCGA). Multivariate Cox proportional hazard model was applied to screening of m6A regulators whose mRNA expressions were significantly associated with CRC tumor samples' overall survival (OS) probability and those significant regulators were used for LASSO regression analysis to construct CRC prognosis prediction signature. As a result, two regulators i.e., YTHDC2 and ALKBH5 were picked out in multivariate analysis. CRC prognosis signature was constructed based on those two regulators through which CRC tumor samples with favorable and inferior prognosis could definitely be distinguished independent of potential confounding factors. This study should be helpful for identifying prognostic different CRC patients and guiding therapeutic method selection.

Evaluation of serum midkine and carcinoembryonic antigen as diagnostic biomarkers for rectal cancer and synchronous metastasis.

METHODS: S-MK and CEA, related to cancer status, were measured in 106 patients and 30 controls by ELISAs. Diagnostic and Prognostic values of S-MK and CEA for rectal cancer were conducted by receiver operating characteristic (ROC) curves with the analysis of sensitivity, specificity, diagnostic accuracy, positive predictive value (PPV) and negative predictive value (NPV) for differential diagnosis. RESULTS: Pre-surgical S-MK was elevated in cancer patients than the normal and benign subjects. In term of phases, S-MK and CEA of T3/T4 were both significantly higher than those in T1/T2, with further up-regulation of S-MK. The diagnostic capability of S-MK was higher than CEA and increased in integrating S-MK with CEA when differentiated rectal cancer, benign rectal polyps and normal subjects. Moreover, when evaluating metastasis predictive efficacies, the combination of S-MK and CEA showed higher accuracy than any individual parameter. CONCLUSIONS: Pre-surgical S-MK is a rectal cancer indicator which is superior to CEA. It can potentially be used to monitor the prognosis of rectal cancer, and predict synchronous metastases, providing assistance to clinicians.

Identification of a 5­lncRNA signature­based risk scoring system for survival prediction in colorectal cancer.

The present study aimed to investigate potential prognostic long noncoding RNAs (lncRNAs) associated with colorectal cancer (CRC). An mRNA­seq dataset obtained from The Cancer Genome Atlas was employed to identify the differentially expressed lncRNAs (DELs) between CRC patients with good and poor prognoses. Subsequently, univariate and multivariate Cox regression analyses were conducted to analyze the prognosis­associated lncRNAs among all DELs. In addition, a risk scoring system was developed according to the expression levels of the prognostic lncRNAs, which was then applied to a training set and an independent testing set. Furthermore, the co­expressed genes of prognostic lncRNAs were screened using a Multi­Experiment Matrix online tool for construction of lncRNA­gene networks. Finally, Kyoto Encyclopedia of Genes and Genomes pathway and Gene Ontology (GO) function enrichment analyses were performed on genes in the lncRNA­gene networks using KOBAS, GOATOOLS and ClusterProfiler. The present study identified 82 DELs, of which long intergenic nonprotein coding RNA 2159, RP11­452L6.6, RP11­894P9.1 and RP11­69M1.6, and whey acidic protein four­disulfide core domain 21 (WFDC21P) were reported to be independently associated with the prognosis of patients with CRC. A 5­lncRNA signature­based risk scoring system was developed, which may be used to classify patients into low­ and high­risk groups with significantly different recurrence­free survival times in the training and testing sets (P<0.05). Co­expressed genes of WFDC21P or RP11­69M1.6 were utilized to construct the lncRNA­gene networks. Genes in the networks were significantly enriched in 'tight junction', 'focal adhesion' and 'regulation of actin cytoskeleton' pathways, and numerous GO terms associated with 'reactive oxygen species metabolism' and 'nitric oxide metabolism'. The present study proposed a 5­lncRNA signature­based risk scoring system for predicting the prognosis of patients with CRC, and revealed the associated signaling pathways and biological processes. The results of the present study may help improve prognostic evaluation in clinical practice.

[Correlation between the activation of AP-1 signal transduction pathway and metastasis of colorectal carcinoma].

OBJECTIVE: To investigate the binding activity of activator protein-1 (AP-1) with DNA probe in the colorectal carcinoma (CRC) tissues and surrounding tissues and explore the correlation between the activation of AP-1 signal transduction pathway and metastasis of CRC. METHODS: The AP-1 DNA binding activities were investigated by electrophoretic mobility shift assay (EMSA) in CRC specimens (T), surrounding tissues including 2 cm (P(2)), 5 cm(P(5)) far away from primary tumor margin and distal resection margin of the specimens (N). The mRNA expression level of vascular endothelial growth factor (VEGF), matrix metalloproteinase-9 (MMP-9) were measured by quantitive reverse transcription polymerase chain reaction (Q- RT-PCR). RESULTS: The AP-1 DNA binding activity in T was significantly higher than those in P(2), P(5) and N (P< 0.05) tissues. There were significantly positive correlations between AP-1 DNA binding activity in tumor and invasive degree, lymphatic metastasis respectively (P< 0.01), but no correlation with histological classification and differentiation (P> 0.05). The transcription levels of VEGF and MMP-9 in CRC were significantly higher than those in P(5) and N (P< 0.01, P< 0.05) tissues. The transcription levels of VEGF and MMP-9 were significantly correlated with increasing AP-1 DNA binding activity (P< 0.01). CONCLUSIONS: AP-1 is significantly correlated to the invasion and metastasis in CRC. The activation of AP-1 signal transduction pathway might be involved in the angiogenesis and of degradation extracellular matrix during tumor metastasis.