Down-regulated miR-625 suppresses invasion and metastasis of gastric cancer by targeting ILK. FEBS Lett. 2012;586:2382-2388. [PMID: 22677169 DOI: 10.1016/j.febslet.2012.05.050]

Decreased expression of microRNA-625 is associated with tumor metastasis and poor prognosis in patients with colorectal cancer

BACKGROUND

MicroRNAs (miRNAs) play an essential role in colorectal cancer (CRC) development and progression. Aberrant miR-625 expression has been reported in several cancers. However, the clinical significance of miR-625 in human CRC has not been addressed.

METHODS

miR-625 expression was determined in 96 pairs of primary CRC and their corresponding adjacent nontumor tissues by quantitative reverse transcriptase-polymerase chain reaction. Associations of miR-625 expression with demographic and clinicopathologic features were determined. Additionally, the effects of ectopic expression of miR-625 on cell migration and invasion were investigated in vitro and in vivo.

RESULTS

miR-625 was significantly downregulated in CRC tissues and cell lines. In addition, the decreased expression of miR-625 was positively associated with advanced lymph node metastasis (P = 0.038), liver metastasis (P = 0.031), poor overall survival (P = 0.002), and an unfavorable prognosis for CRC patients, as determined through a multivariate analysis (P = 0.034). Moreover, functional assays demonstrated that ectopic miR-625 expression inhibits the invasion and migration of HCT116 CRC cells both in vitro and in vivo.

CONCLUSIONS

Our results suggest that miR-625 may serve as an efficient clinical biomarker and a therapeutic tool for the inhibition of metastasis in CRC.

miRNA: The nemesis of gastric cancer (Review)

microRNAs (miRNAs) are a group of small non-coding RNAs that are ~22 (18 to 25) nucleotides (nt) long and have been associated with a variety of diseases, including cancer. Increasing evidence indicates that miRNAs are essential in the development, diagnosis, treatment and prognosis of a variety of tumors. The utility of miRNAs as biomarkers for diagnosis and of target molecules for the treatment of cancers is increasingly being recognized. With the discovery of circulating miRNAs, a non-invasive approach for the diagnosis and treatment of cancer has been identified. This review summarizes the role of miRNAs in the development of different tumors, as well as a variety of other biological events. Moreover, this review focuses on analyzing the function and mechanism of gastric cancer-related miRNAs and investigates the importance of circulating miRNAs in gastric cancer, as well as their origin. Finally, this review lists a number of the problems that must be solved prior to miRNAs being used as reliable non-invasive tools for the diagnosis, treatment and prognosis of gastric cancer.

Exploration of tumor-suppressive microRNAs silenced by DNA hypermethylation in cervical cancer

Background

Multiple studies proved that miRNAs have a causal role in tumorigenesis. Some miRNAs are regulated by epigenetic alterations in their promoter regions and can be activated by chromatin- modifying drugs.

Methods

We treated cervical cancer cells with 5-aza-2’-deoxycytidine and get a microarray analysis. Dysregulation of miRNAs was measured by qPCR in cervical cell lines and methylation status of them in cervical cancer tissue were performed with MeDIP-qPCR assay.

Results

We found hypermethylation of miR-432, miR-1286, miR-641, miR-1290, miR-1287 and miR-95 may have some relationship with HPV infection in cervical cell lines. In primary tumors of cervix with paired normal tissue, expression levels of miRNAs were inversely correlated with their DNA methylation status in the cervical cancer cell lines treated with 5-AZA.

Conclusions

Our results indicate that miRNAs might play a role in the pathogenesis of human cervical cancer with HPV and identify altered miRNA methylation as a possible epigenetic mechanism involved in their aberrant expression.

Small interfering RNA targeting ILK inhibits metastasis in human tongue cancer cells through repression of epithelial-to-mesenchymal transition

Integrin-linked kinase (ILK) is a multifunctional serine/threonine kinase. Accumulating evidences suggest that ILK are involved in cell-matrix interactions, cell proliferation, invasion, migration, angiogenesis and Epithelial-mesenchymal transition (EMT). However, the underlying mechanisms remain largely unknown. EMT has been postulated as a prerequisite for metastasis. The reports have demonstrated that EMT was implicated in metastasis of oral squamous cell carcinomas. Therefore, here we further postulate that ILK might participate in EMT of tongue cancer. We showed that ILK siRNA inhibited EMT with low N-cadherin, Vimentin, Snail, Slug and Twist as well as high E-cadherin expression in vivo and in vitro. We found that knockdown of ILK inhibited cell proliferation, migration and invasion as well as changed cell morphology. We also demonstrated that ILK siRNA inhibited phosphorylation of downstream signaling targets Akt and GSK3β as well as reduced expression of MMP2 and MMP9. Furthermore, we found that the tongue tumor with high metastasis capability showed higher ILK, Vimentin, Snail, Slug and Twist as well as lower E-cadherin expression in clinical specimens. Finally, ILK siRNA led to the suppression for tumorigenesis and metastasis in vivo. Our findings suggest that ILK could be a novel diagnostic and therapeutic target for tongue cancer.

Epigenetic analysis of the Notch superfamily in high-grade serous ovarian cancer

OBJECTIVES

Gene methylation and other epigenetic modifications of gene regulation have been implicated in the growth of ovarian cancer, but the clinical significance of such modifications in the Notch pathway in high-grade serous ovarian cancer (HGS-OvCa) is not well understood. We used The Cancer Genome Atlas (TCGA) data to study the clinical relevance of epigenetic modifications of Notch superfamily genes.

METHODS

We analyzed the interaction of DNA methylation and miRNAs with gene expression data for Notch superfamily members with the Spearman rank correlation test and explored potential relationships with overall survival (OS) with the log-rank test. We downloaded clinical data, level 3 gene expression data, and level 3 DNA methylation data for 480 patients with stage II-IV HGS-OvCa from the TCGA data portal. Patients were randomly divided into training and validation cohorts for survival analyses. In each set, patients were grouped into percentiles according to methylation and microRNA (miRNA) or messenger RNA (mRNA) levels. We used several algorithms to predict miRNA-mRNA interaction.

RESULTS

There were significant inverse relationships between methylation status and mRNA expression for PPARG, CCND1, and RUNX1. For each of these genes, patients with a lower methylation level and higher expression level had significantly poorer OS than did patients with a higher methylation level and lower expression level. We also found a significant inverse relationship between miRNAs and mRNA expression for CCND1, PPARG, and RUNX1. By further analyzing the effect of miRNAs on gene expression and OS, we found that patients with higher levels of CCND1, PPARG, and RUNX1 expression and lower expression levels of their respective miRNAs (502-5p, 128, and 215/625) had significantly poorer OS.

CONCLUSIONS

Epigenetic alterations of multiple Notch target genes and pathway interacting genes (PPARG, CCND1, and RUNX1) may relate to activation of this pathway and poor survival of patients with HGS-OvCa.

Identification of a set of miRNAs differentially expressed in transiently TIA-depleted HeLa cells by genome-wide profiling

BACKGROUND

T-cell intracellular antigen (TIA) proteins function as regulators of cell homeostasis. These proteins control gene expression globally at multiple levels in response to dynamic regulatory changes and environmental stresses. Herein we identified a micro(mi)RNA signature associated to transiently TIA-depleted HeLa cells and analyzed the potential role of miRNAs combining genome-wide analysis data on mRNA and miRNA profiles.

RESULTS

Using high-throughput miRNA expression profiling, transient depletion of TIA-proteins in HeLa cells was observed to promote significant and reproducible changes affecting to a pool of up-regulated miRNAs involving miR-30b-3p, miR125a-3p, miR-193a-5p, miR-197-3p, miR-203a, miR-210, miR-371-5p, miR-373-5p, miR-483-5p, miR-492, miR-498, miR-503-5p, miR-572, miR-586, miR-612, miR-615-3p, miR-623, miR-625-5p, miR-629-5p, miR-638, miR-658, miR-663a, miR-671-5p, miR-769-3p and miR-744-5p. Some up-regulated and unchanged miRNAs were validated and previous results confirmed by reverse transcription and real time PCR. By target prediction of the miRNAs and combined analysis of the genome-wide expression profiles identified in TIA-depleted HeLa cells, we detected connections between up-regulated miRNAs and potential target genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) database analysis suggest that target genes are related with biological processes associated to the regulation of DNA-dependent transcription, signal transduction and multicellular organismal development as well as with the enrichment of pathways involved in cancer, focal adhesion, regulation of actin cytoskeleton, endocytosis and MAPK and Wnt signaling pathways, respectively. When the collection of experimentally defined differentially expressed genes in TIA-depleted HeLa cells was intersected with potential target genes only 7 out of 68 (10%) up- and 71 out of 328 (22%) down-regulated genes were shared. GO and KEGG database analyses showed that the enrichment categories of biological processes and cellular pathways were related with innate immune response, signal transduction, response to interleukin-1, glomerular basement membrane development as well as neuroactive ligand-receptor interaction, endocytosis, lysosomes and apoptosis, respectively.

CONCLUSION

All this considered, these observations suggest that individual miRNAs could act as potential mediators of the epigenetic switch linking transcriptomic dynamics and cell phenotypes mediated by TIA proteins.

Downregulated microRNA-200a promotes EMT and tumor growth through the wnt/β-catenin pathway by targeting the E-cadherin repressors ZEB1/ZEB2 in gastric adenocarcinoma

In a previous study, we found that microRNA (miRNA)-200a suppresses Wnt/β-catenin signaling by interacting with β-catenin, thereby inhibiting migration, invasion and proliferation. However, the mechanism involved in this suppression remains unclear. In the present study, we investigated the underlying mechanism of miR-200a regulation of epithelial-mesenchymal transition (EMT) in gastric carcinoma cells, and confirmed the tumor suppressor role of miR-200a in vivo. The expressions of miRNA-200a, -200b and -200c, identified by fluorescent in situ hybridization, were downregulated and inversely correlated with WHO grades of gastric adenocarcinoma (GA). The expression of the potential miR-200a target genes ZEB1 and ZEB2 was detected immunohistochemically. These examinations used the same tissue microarrays to analyze the relationships between miR-200a and potential target genes. The expression of miR-200a and ZEB1/ZEB2 in the same GA tissue microarrays was inversely related. Restored miR-200a expression inhibited tumor growth in nude mice harboring subcutaneous SGC7901 xenografts. The expression of N-cadherin, β-catenin, Twist1 and Snail2 decreased, and E-cadherin levels increased, when miR-200a was elevated, as tested by fluorescence microscopy and immunohistochemistry. Similar results were observed in vivo. We found upregulated miR-200a expression to increase E-cadherin and suppress the Wnt/β-catenin pathway by targeting ZEB1 and ZEB2 in GA, thus delaying tumor growth in vivo. The effect of miR-200a on Wnt/β-catenin signaling may provide a therapeutic target against EMT.