miR-145 and miR-133a function as tumour suppressors and directly regulate FSCN1 expression in bladder cancer

Background:

We have recently identified down-regulated microRNAs including miR-145 and miR-133a in bladder cancer (BC). The aim of this study is to determine the genes targeted by miR-145, which is the most down-regulated microRNA in BC.

Methods:

We focused on fascin homologue 1 (FSCN1) from the gene expression profile in miR-145 transfectant. The luciferase assay was used to confirm the actual binding sites of FSCN1 mRNA. Cell viability was evaluated by cell growth, wound-healing, and matrigel invasion assays. BC specimens were subjected to immunohistochemistry of FSCN1 and in situ hybridisation of miR-145.

Results:

The miR-133a as well as miR-145 had the target sequence of FSCN1 mRNA by the database search, and both microRNAs repressed the mRNA and protein expression of FSCN1. The luciferase assay revealed that miR-145 and miR-133a were directly bound to FSCN1 mRNA. Cell viability was significantly inhibited in miR-145, miR-133a, and si-FSCN1 transfectants. In situ hybridisation revealed that miR-145 expression was markedly repressed in the tumour lesion in which FSCN1 was strongly stained. The immunohistochemical score of FSCN1 in invasive BC (n=46) was significantly higher than in non-invasive BC (n=20) (P=0.0055).

Conclusion:

Tumour suppressive miR-145 and miR-133a directly control oncogenic FSCN1 in BC.     

The tumour-suppressive function of miR-1 and miR-133a targeting TAGLN2 in bladder cancer

Background:

On the base of the microRNA (miRNA) expression signature of bladder cancer (BC), we found that miR-1 and miR-133a were significantly downregulated in BC. In this study, we focussed on the functional significance of miR-1 and miR-133a in BC cell lines and identified a molecular network of these miRNAs.

Methods and results:

We investigated the miRNA expression signature of BC clinical specimens and identified several downregulated miRNAs (miR-133a, miR-204, miR-1, miR-139-5p, and miR-370). MiR-1 and miR-133a showed potential role of tumour suppressors by functional analyses of BC cells such as cell proliferation, apoptosis, migration, and invasion assays. Molecular target searches of these miRNAs showed that transgelin 2 (TAGLN2) was directly regulated by both miR-1 and miR-133a. Silencing of TAGLN2 study demonstrated significant inhibitions of cell proliferation and increase of apoptosis in BC cell lines. The immunohistochemistry showed a positive correlation between TAGLN2 expression and tumour grade in clinical BC specimens.

Conclusions:

The downregulation of miR-1 and miR-133a was a frequent event in BC, and these miRNAs were recognised as tumour suppressive. TAGLN2 may be a target of both miRNAs and had a potential oncogenic function. Therefore, novel molecular networks provided by miRNAs may provide new insights into the underlying molecular mechanisms of BC.     

Identification of novel molecular targets regulated by tumor suppressive miR-1/miR-133a in maxillary sinus squamous cell carcinoma

Based on our microRNA (miRNA) expression signature analysis of maxillary sinus squamous cell carcinoma (MSSCC), we found that miR-1 and miR-133a were significantly reduced in tumor tissues. Quantitative real-time RT-PCR revealed that the expression levels of miR-1 and miR-133a were significantly downregulated in clinical MSSCC tumor tissues compared with normal tissues. We focused on the functional significance of miR-1 and miR-133a in cancer cells and identification of the novel cancer networks regulated by these miRNAs in MSSCC. Restoration of downregulated miRNAs (miR-1 or miR-133a) in cancer cells revealed that both miRNAs significantly inhibited cancer cell proliferation and induced cell apoptosis. Molecular target identification of these miRNAs showed that transgelin 2 (TAGLN2) and purine nucleoside phosphorylase (PNP) were regulated by miR-1 and miR-133a. Both TAGLN2 and PNP mRNA expression levels were significantly upregulated in clinical MSSCC tumor tissues. Silencing studies of target genes demonstrated that both genes inhibited cancer cell proliferation. The identification of novel miR-1/miR-133a-regulated cancer pathways could provide new insights into potential molecular mechanisms of MSSCC oncogenesis.     

Tumour suppressors miR-1 and miR-133a target the oncogenic function of purine nucleoside phosphorylase (PNP) in prostate cancer

Background:

Our recent analyses of miRNA expression signatures showed that miR-1 and miR-133a were significantly reduced in several types of cancer. Interestingly, miR-1 and miR-133a are located on the same chromosomal locus in the human genome. We examined the functional significance of miR-1 and miR-133a in prostate cancer (PCa) cells and identified the novel molecular targets regulated by both miR-1 and miR-133a.

Methods and Results:

The expression levels of miR-1 and miR-133a were significantly downregulated in PCa compared with non-PCa tissues. Restoration of miR-1 or miR-133a in PC3 and DU145 cells revealed significant inhibition of proliferation, migration, and invasion. Molecular target identification by genome-wide gene expression analysis and luciferase reporter assay showed that purine nucleoside phosphorylase (PNP) was directly regulated by both miRNAs. Silencing of the PNP gene inhibited proliferation, migration, and invasion in both PC3 and DU145 cells. Immunohistochemistry detected positive staining of PNP in PCa specimens.

Conclusions:

Downregulation of miR-1 and miR-133a was a frequent event in PCa and both function as tumour suppressors. The PNP is a novel target gene of both miRNAs and potentially functions as an oncogene. Therefore, identification of novel molecular networks regulated by miRNAs may provide new insights into the underlying causes of PCa oncogenesis.     

miR-133b acts as a tumor suppressor and negatively regulates FGFR1 in gastric cancer

MicroRNAs (miRNAs) are a class of small noncoding RNAs that negatively regulate protein expression by binding protein-coding mRNAs and repressing translation. Accumulating evidence suggests that miRNAs are involved in cancer development and progression, acting as either tumor suppressors or oncogenes. Intriguingly, it has been shown that miR-133b was significantly downregulated in several types of cancers. However, its role and relevance in gastric cancer are still largely unknown. We showed that miR-133b was downregulated in human gastric cancer tissues and cell lines compared with nontumor counterparts by quantitative RT-PCR analysis. Overexpression of miR-133b could inhibit cell proliferation and colony formation of the gastric cancer cell lines MKN-45 and SGC-7901. Bioinformatics analysis indicated two putative miR-133b binding sites in the 3′-untranslated region of fibroblast growth factor receptor 1 (FGFR1) mRNA. In dual-luciferase reporter assay, miR-133b reduced the luciferase activity of Luc-FGFR1-wt, and mutation of miR-133b binding sites abolished the inhibitory effect of miR-133b. In this study, we found that miR-133b reduced the protein but not the mRNA levels of endogenous FGFR1. Furthermore, FGFR1 expression was upregulated in gastric cancer tissues and inversely correlated with miR-133b expression. Finally, knockdown of FGFR1 inhibited the growth of MKN-45 cells in a dose-dependent manner and overexpression of FGFR1 promoted the growth of GES-1 cells. These results indicate that miR-133b targets FGFR1 and inhibits gastric cancer cell growth, suggesting that it may serve as a tumor suppressive target in gastric cancer therapy.     

Caveolin-1 mediates tumor cell migration and invasion and its regulation by miR-133a in head and neck squamous cell carcinoma

MicroRNAs (miRNAs) are small non-coding RNAs of approximately 22 nucleotides that can function as oncogenes or tumor suppressors in human cancer. Down-regulation of the miRNA miR-133a in many type of cancers, and a reduction of cell proliferation, migration, and invasion upon over-expression, suggests that miR-133a is a tumor suppressor. In this study, genome-wide gene expression analysis of HNSCC cells that over-express miR-133a showed that caveolin-1 (CAV1), a multifunctional scaffolding protein, is down-regulated, a result that was confirmed by real-time PCR and Western blot analysis. A luciferase reporter assay revealed that miR-133a is directly bound to CAV1 mRNA. Cancer cell migration and invasion were significantly inhibited in HNSCC cells transfected with si-CAV1. Therefore, CAV1 functions as an oncogene in HNSCC. The identification of tumor suppressive miRNAs and their target genes could provide new insights into potential mechanism of HNSCC carcinogenesis.     

MicroRNA-133a regulates the mRNAs of two invadopodia-related proteins,FSCN1 and MMP14, in esophageal cancer

Background:

FSCN1 and matrix metalloproteinase 14 (MMP14) are both invadopodia-related proteins. We herein elucidate the tumourigenicity of these proteins and identify novel therapeutic agents in esophageal squamous cell carcinoma (ESCC).

Methods:

FSCN1 and MMP14 were evaluated by immunohistochemistry and quantitative PCR, and microRNA (miR)-133a was also evaluated by PCR in surgical ESCC specimens. The roles of FSCN1, MMP14 and miR-133a were established in ESCC cells.

Results:

The expression of FSCN1 or MMP14 was an independent poor prognostic factor according to a multivariate analysis of immunohistochemistry, and their co-expression correlated with the poorest overall survival (OS) out of all the examined factors. Additionally, their mRNAs significantly correlated and both inversely correlated with miR-133a in surgical specimens. Transfection of a miR-133a mimic decreased the mRNA and protein levels of both FSCN1 and MMP14 in ESCC cells. The knockdown of FSCN1 or MMP14 and transfection of a miR-133a mimic inhibited the proliferation and invasion of ESCC cells. Patients with a lower miR-133a expression have a significantly poorer OS than those with a higher expression.

Conclusion:

The combined expression of FSCN1 and MMP14 is associated with a poor prognosis, and miR-133a, which regulates their mRNAs, can serve as a strong tumour suppressor of ESCC.     

The microRNA-23b/27b/24-1 cluster is a disease progression marker and tumor suppressor in prostate cancer

Our recent study of microRNA (miRNA) expression signatures in prostate cancer (PCa) has revealed that all members of the miR-23b/27b/24-1 cluster are significantly downregulated in PCa tissues. The aim of this study was to investigate the effectiveness of these clustered miRNAs as a disease progression marker and to determine the functional significance of these clustered miRNAs in PCa. Expression of the miR-23b/27b/24-1 cluster was significantly reduced in PCa tissues. Kaplan-Meier survival curves showed that low expression of miR-27b predicted a short duration of progression to castration-resistant PCa. Gain-of-function studies using mature miR-23b, miR-27b, and miR-24-1 significantly inhibited cell proliferation, migration and invasion in PCa cells (PC3 and DU145). To identify the molecular targets of these miRNAs, we carried out gene expression and in silico database analyses. GOLM1 was directly regulated by miR-27b in PCa cells. Elucidation of the molecular targets and pathways regulated by the tumor-suppressive microRNAs should shed light on the oncogenic and metastatic processes in PCa.     

微小RNA-133b在胃癌中的表达及意义

目的 研究miR-133b在胃癌细胞、正常胃黏膜上皮永生化细胞、胃癌组织及相应癌旁组织中的表达,探讨miRNA对胃癌发生发展的调控作用。方法 培养7种胃癌细胞株及正常胃黏膜上皮细胞,并收集56例胃癌患者癌组织及相应癌旁组织,提取细胞及组织中总的Small RNA,采用real-timePCR法检测miR-133b在胃癌细胞及组织中的表达,分析miR-133b的表达与细胞分化程度、临床病理特征的关系。结果 miR-133b在胃癌细胞及组织中均表达下调,差异具有统计学意义。miR-133b的低表达与细胞分化程度、TNM分期及有无淋巴结转移显著相关。结论 miR-133b在胃癌细胞及胃癌组织中的表达明显下调,可能作为抑癌基因参与胃癌的发生、发展。     

Distinct microRNA expression profiles in prostate cancer stem/progenitor cells and tumor-suppressive functions of let-7

MiRNAs regulate cancer cells, but their potential effects on cancer stem/progenitor cells are still being explored. In this study, we used quantitative real-time-PCR to define miRNA expression patterns in various stem/progenitor cell populations in prostate cancer, including CD44+, CD133+, integrin α2β1+, and side population cells. We identified distinct and common patterns in these different tumorigenic cell subsets. Multiple tumor-suppressive miRNAs were downregulated coordinately in several prostate cancer stem/progenitor cell populations, namely, miR-34a, let-7b, miR-106a, and miR-141, whereas miR-301 and miR-452 were commonly overexpressed. The let-7 overexpression inhibited prostate cancer cell proliferation and clonal expansion in vitro and tumor regeneration in vivo. In addition, let-7 and miR-34a exerted differential inhibitory effects in prostate cancer cells, with miR-34a inducing G1 phase cell-cycle arrest accompanied by cell senescence and let-7 inducing G2-M phase cell-cycle arrest without senescence. Taken together, our findings define distinct miRNA expression patterns that coordinately regulate the tumorigenicity of prostate cancer cells.     

The functional significance of miR-1 and miR-133a in renal cell carcinoma

PurposeThe aim of this study was to find a novel molecular network involved in renal cell carcinoma (RCC) development through investigating the functions of miR-1 and miR-133a and their target genes.MethodsWe checked the expression levels of miR-1 and miR-133a in RCC cell lines and specimens (N = 40) using real time RT-PCR. MiR-1 and miR-133a transfectants were subjected to a gain-of-function study to identify the functions of the miRNAs. To find the target genes of the miRNAs, we analysed the gene expression profile of their transfectants and performed a luciferase reporter assay. mRNA expression levels of the candidate target gene in the clinical specimens were examined, and loss-of-function studies were performed.ResultsThe expression levels of miR-1 and miR-133a were significantly suppressed in RCC cell lines and specimens. Ectopic restoration of miR-1 and miR-133a showed significant inhibition of cell proliferation and invasion, and moreover, revealed induction of apoptosis and cell cycle arrest. The luciferase assay revealed transgelin-2 (TAGLN2), selected as a target gene for miR-1 and miR-133a on the basis of the gene expression profile, to be directly regulated by both miR-1 and miR-133a. The loss-of-function studies showed significant inhibitions of cell proliferation and invasion in the si-TAGLN2 transfectant. The expression level of TAGLN2 mRNA was significantly up-regulated in the RCC specimens; in addition, there was a statistically significant inverse correlation between TAGLN2 and miR-1 and miR-133a expression.ConclusionsOur data indicate that up-regulation of the oncogenic TAGLN2 was due to down-regulation of tumour-suppressive miR-1 and miR-133a in human RCC.     

miR-133a-5p suppresses gastric cancer through TCF4 down-regulation

BackgroundThe effect of microRNAs (miRNA) on cancer regulations has received a considerable amount of attention recently. MiR-133a-5p has been identified as an anti-tumor miRNA in several types of cancers. However, the effect of miR-133a-5p on gastric cancer (GC) have not been uncovered. In this study, we sought to evaluate the regulation of TCF4 expression by miR-133-5p and the role of the miR-25-3p/TCF4 axis in the progression of GC, with the aim of identifying a potential therapeutic target for GC.MethodsTCGA (The Cancer Genome Atlas), GTEx (The Genotype-Tissue Expression) and GEO (Gene Expression Omnibus) database were used to analyze the expression and prognosis. We performed MTT and EdU assays to elucidate the effect on cell replication. Apoptotic cells were stained with annexin V-fluorescein isothiocyanate and propidium iodide to stain, and then analyzed by flow cytometry. The effect on cell metastasis was investigated in wound healing and transwell assays. A dual-luciferase reporter assay was used to check for the direct targeting of TCF4 by miR-133a-5p. Bioinformatic analysis of the relationship of TCF4 with tumor microenvironment and the signaling cascade of TCF4 was finally performed.ResultsWe found that the level of miR-133a-5p was decreased in both tumor tissues and GC cell lines. MiR-133a-5p inhibited cell growth and metastasis, but promoted cell apoptosis. MiR-133a-5p directly targeted TCF4 and downregulated its expression. TCF4 was highly expressed in tumor and higher level of TCF4 indicated poorer prognosis. Moreover, TCF4 overexpression reversed the aforementioned anti-tumor activity of miR-133a-5p. The expression level of TCF4 was significantly correlated with tumor-infiltrating immune cells.ConclusionsOur findings altogether reveal that miR-133a-5p can serve as a tumor suppressor in gastric cancer via the miR-133a-5p/TCF4 pathway.     

Epigenetic regulation of miR-34b and miR-129 expression in gastric cancer

MicroRNAs (miRNAs) are small noncoding RNAs that play fundamental roles in diverse biological and pathological processes by targeting the expression of specific genes. Here, we identified 38 methylation-associated miRNAs, the expression of which could be epigenetically restored by cotreatment with 5-aza-2'-deoxycytidine and trichostatin A. Among these 38 miRNAs, we further analyzed miR-34b, miR-127-3p, miR-129-3p and miR-409 because CpG islands are predicted adjacent to them. The methylation-silenced expression of these miRNAs could be reactivated in gastric cancer cells by treatment with demethylating drugs in a time-dependent manner. Analysis of the methylation status of these miRNAs showed that the upstream CpG-rich regions of mir-34b and mir-129-2 are frequently methylated in gastric cancer tissues compared to adjacent normal tissues, and their methylation status correlated inversely with their expression patterns. The expression of miR-34b and miR-129-3p was downregulated by DNA hypermethylation in primary gastric cancers, and the low expression was associated with poor clinicopathological features. In summary, our study shows that tumor-specific methylation silences miR-34b and miR-129 in gastric cancer cells.