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.     

Cyclin G1 is a target of miR-122a, a microRNA frequently down-regulated in human hepatocellular carcinoma

We investigated the role of microRNAs (miRNAs) in the pathogenesis of human hepatocellular carcinoma (HCC). A genome-wide miRNA microarray was used to identify differentially expressed miRNAs in HCCs arisen on cirrhotic livers. Thirty-five miRNAs were identified. Several of these miRNAs were previously found deregulated in other human cancers, such as members of the let-7 family, mir-221, and mir-145. In addition, the hepato-specific miR-122a was found down-regulated in approximately 70% of HCCs and in all HCC-derived cell lines. Microarray data for let-7a, mir-221, and mir-122a were validated by Northern blot and real-time PCR analysis. Understanding the contribution of deregulated miRNAs to cancer requires the identification of gene targets. Here, we show that miR-122a can modulate cyclin G1 expression in HCC-derived cell lines and an inverse correlation between miR-122a and cyclin G1 expression exists in primary liver carcinomas. These results indicate that cyclin G1 is a target of miR-122a and expand our knowledge of the molecular alterations involved in HCC pathogenesis and of the role of miRNAs in human cancer.     

Serum miRNA Panel in Egyptian Patients with Chronic Hepatitis C Related Hepatocellular Carcinoma

Background: Primary hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. MicroRNAs (miRNAs) have great HCC diagnostic potential and circulating miRNAs have been reported as promising biomarkers for various pathologic conditions. Aim: To explore the potential benefit of serum miR-126, miR-129, miR-155, miR-203 and miR-223 as non-invasive diagnostic markers of hepatitis C virus (HCV)-related HCC. Materials and Methods: The expression of miRNA was evaluated using real-time quantitative RT-PCR in 78 serum samples (30 treatment-naive chronic HCV, 25 post-HCV compensated cirrhosis and 23 treatment- naive HCC cases). Results: Comparing miRNA fold changes in the HCC group vs the non HCC groups, there was significant fold decrease in miR-126 (P= 0.034), miR-129 (P= 0.006), miR-155 (P= 0.011), miR-203 (<0.001) and miR-223 (P= 0.013). The highest AUC to differentiate HCC patients from non-HCC was 0.76 for miR-203. Conclusions: Among studied miRNAs, serum miR-203 has the highest potential as a non-invasive biomarker of HCC.     

miRNA let-7f-1-3p在伯基特淋巴瘤中的差异性分析

目的 研究伯基特淋巴瘤（BL）中差异表达的miRNA,探讨可用于BL鉴别诊断的miRNA标志物.方法 收集BL病例,miRNA芯片筛选其与淋巴结反应性增生之间的差异miRNA表达谱;运用miRWalk数据库对差异miRNA进行靶基因预测;利用MAS3对靶基因进行GO注释和KEGG信号通路分析.结果 与淋巴结反应性增生组织相比,BL中共有46个表达异常的miRNA,包括3 1个上调miRNA和15个下调miRNA;对miRNA let-7f-1-3p靶基因预测得到2837条靶基因,与BL密切相关的基因有16个：CENPC1、FANCF、IL4R等;GO注释显示主要涉及多细胞器官发育,RNA聚合酶Ⅱ启动子转录调控等生物学过程,KEGG分析显示主要涉及癌症信号通路,TGF-beta信号通路中.结论 在BL中发现了表达异常的miRNA,生物信息学分析对差异miRNA分析结果提示,这些差异miRNA可以作为BL鉴别诊断的新肿瘤标志物.     

Identification of let-7-regulated oncofetal genes

MicroRNAs (miRNA) are small RNA molecules of approximately 20 to 22 nucleotides that reduce expression of proteins through mRNA degradation and/or translational silencing. Each known miRNA has a large number of predicted targets. Members of the let-7/miR-98 family of miRNAs are up-regulated at the end of embryonic development. Let-7 is often down-regulated early during cancer development, suggesting that let-7-regulated oncofetal genes (LOG) may become reexpressed in cancer cells. Using comparative bioinformatics, we have identified 12 conserved LOGs that include HMGA2 and IMP-1/CRD-BP. IMP-1 has growth-promoting activities through stabilization of c-myc mRNA. We experimentally confirmed that IMP-1 is a direct let-7 target that promotes cell growth and motility of tumor cells, and we confirmed by proteomics analysis that IMP-1 and HMGA2 are major miRNA targets. Our data suggest that a substantial part of the growth inhibitory activities of let-7 comes from suppressing the expression of IMP-1. LOGs could be novel therapeutic targets and potential biomarkers for cancer treatment.     

microRNA Expression Profile in Patients with Stage II Colorectal Cancer: A Turkish Referral Center Study

Background: There are increasing data about microRNAs (miRNA) in the literature, providing abundantevidence that they play important roles in pathogenesis and development of colorectal cancer. In this study, weaimed to investigate the miRNA expression profiles in surgically resected specimens of patients with recurrentand non-recurrent colorectal cancer. Materials and Methods: The study population included 40 patients withstage II colorectal cancer (20 patients with recurrent tumors, and 20 sex and age matched patients withoutrecurrence), who underwent curative colectomy between 2004 and 2011 without adjuvant therapy. Expression of16 miRNAs (miRNA-9, 21, 30d, 31, 106a, 127, 133a, 133b, 135b, 143, 145, 155, 182, 200a, 200c, 362) was verifiedby quantitative real-time polymerase chain reaction (qRT-PCR) in all resected colon cancer tissue samples andin corresponding normal colonic tissues. Data analyses were carried out using SPSS 15 software. Values werestatistically significantly changed in 40 cancer tissues when compared to the corresponding 40 normal colonictissues (p<0.001). MiR-30d, miR-133a, miR-143, miR-145 and miR-362 expression was statistically significantlydownregulated in 40 resected colorectal cancer tissue samples (p<0.001). When we compared subgroups,miRNA expression profiles of 20 recurrent cancer tissues were similar to all 40 cancer tissues. However in 20non-recurrent cancer tissues, miR-133a expression was not significantly downregulated, moreover miR-133bexpression was significantly upregulated (p<0.05). Conclusions: Our study revealed dysregulation of expressionof ten miRNAs in Turkish colon cancer patients. These miRNAs may be used as potential biomarkers for earlydetection, screening and surveillance of colorectal cancer, with functional effects on tumor cell behavior.     

microRNAs in uterine sarcomas and mixed epithelial–mesenchymal uterine tumors: a preliminary report

Uterine sarcomas and mixed epithelial–mesenchymal uterine tumors are a heterogeneous group of rare tumors for which there are very few diagnostic markers available. As aberrant microRNA (miRNA) expression patterns represent putative diagnostic cancer markers, we aimed to identify miRNA expression profiles of the major uterine sarcoma subtypes and mixed epithelial–mesenchymal tumors of the uterus. Eighty-eight miRNAs were assessed by quantitative RT-PCR in cancerous and non-cancerous tissue samples collected from 29 patients with endometrial sarcoma, leiomyosarcoma, and mixed epithelial–mesenchymal tumors. Tumor and control samples significantly (P?<?0.05) differed in the expression of miR-23b, miR-1, let-7f, and let-7c in endometrial sarcomas, and miR-1, let-7c, miR-133b, let-7b, miR-143, let-7a, let-7d, let-7e, let-7g, miR-222, let-7i, and miR-214 in mixed epithelial–mesenchymal tumors. All the significantly changed miRNAs were down-regulated in the malignant tissues as compared to their normal counterparts. This may suggest their tumor suppressor role in these malignancies. No statistically significant changes in miRNA expression levels were found between leiomyosarcoma tumors and controls. The identified miRNAs warrant further studies as valuable candidate markers for the differential diagnosis of uterine sarcomas from benign uterine lesions and between uterine sarcoma subtypes.     

Expression analysis of liver-specific circulating microRNAs in HCV-induced hepatocellular Carcinoma in Egyptian patients

Objectives: Due to the absence of reliable and accurate biomarkers for the early detection of liver malignancy, circulating microRNAs have recently emerged as great candidates for prompt cancer identification. Therefore, the aim of this study was to investigate the potential of liver-specific circulating microRNAs as an accurate non-invasive diagnostic tool for early diagnosis of hepatitis C virus (HCV)-induced hepatocellular carcinoma (HCC).

Methodology: A total of 165 patients were enrolled in this study and categorized into four main groups: 42 chronic hepatitis C (CHC) without cirrhosis, 45 CHC with cirrhosis (LC), 38 HCC with HCV patients, and 40 healthy controls. The expression profiles of seven miRNAs (miR-16, miR-34a, miR-125a, miR-139, miR-145, miR-199a, and miR-221) were analyzed using real-time PCR.

Results: Serum levels of miRNA-125a, miRNA-139, miRNA-145, and miRNA199a were significantly lower (p < 0.01) in HCC than in both CHC and LC groups. On the other hand, no significant difference was shown in the expression of miR-16, miR-34a, and miR-221 between the CHC, LC, and HCC groups. MiR-16, miR-34a, and miR-221 were significantly elevated in the HCC group compared to the control group. MiR-34a showed the highest specificity and sensitivity.

Conclusions: The results indicated that the measurement of serum levels of miR-125a, miR-139, miR-145, and miR-199a can help to differentiate HCC from CHC and LC. Also, miR-16, miR-34a, and miR-221 serum levels would have a prognostic value. MiR-34a had the highest specificity and sensitivity, indicating that it might serve as a novel and potential non-invasive biomarker for HCV-induced HCC.     

Increased Ras GTPase activity is regulated by miRNAs that can be attenuated by CDF treatment in pancreatic cancer cells

Ras gene is frequently mutated, and also associated with increased Ras expression and its GTPase activity (activity) in pancreatic cancer (PC), which could in part be due to deregulated expression of microRNAs (miRNAs) contributing to tumor aggressiveness. Here we report, for the first time, that Ras expression and its activity were significantly higher in MIAPaCa-2 cells compared to COLO-357 and BxPC-3 cell lines, which was correlated with loss of let-7 family and miR-143 expression in MIAPaCa-2 cells compared to COLO-357 and BxPC-3 cells. Whereas the expression of miR-21, a frequently up-regulated miRNA in solid tumors was up-regulated in MIAPaCa-2 cells and it was correlated with increased Ras expression and its activity. The miRNAs, let-7i and miR-143 was found to target Ras, and forced re-expression of let-7i and miR-143 inhibited Ras activity, cell proliferation and colony formation in vitro. We also found that the treatment of cells in vitro or treatment of MIAPaCa-2 induced tumors in vivo with CDF, a novel synthetic analog of curcumin, led to the re-expression of let-7 and miR-143, and down-regulated miR-21 expression, which was consistent with attenuation of Ras expression and its activity. Moreover, re-expression of let-7iin vivo resulted in decreased tumor growth and Ras activity. These results suggest that the loss of expression of let-7 and miR-143, and increased expression of miR-21 leads to increased expression of Ras and its GTPase activity, which could be attenuated by CDF treatment and, thus CDF could become a novel therapeutic agent for the treatment of PC.     

Screening key microRNAs for castration-resistant prostate cancer based on miRNA/mRNA functional synergistic network

High-throughput methods have been used to explore the mechanisms by which androgen-sensitive prostate cancer (ASPC) develops into castration-resistant prostate cancer (CRPC). However, it is difficult to interpret cryptic results by routine experimental methods. In this study, we performed systematic and integrative analysis to detect key miRNAs that contribute to CRPC development. From three DNA microarray datasets, we retrieved 11 outlier microRNAs (miRNAs) that had expression discrepancies between ASPC and CRPC using a specific algorithm. Two of the miRNAs (miR-125b and miR-124) have previously been shown to be related to CRPC. Seven out of the other nine miRNAs were confirmed by quantitative PCR (Q-PCR) analysis. MiR-210, miR-218, miR-346, miR-197, and miR-149 were found to be over-expressed, while miR-122, miR-145, and let-7b were under-expressed in CRPC cell lines. GO and KEGG pathway analyses revealed that miR-218, miR-197, miR-145, miR-122, and let-7b, along with their target genes, were found to be involved in the PI3K and AKT3 signaling network, which is known to contribute to CRPC development. We then chose five miRNAs to verify the accuracy of the analysis. The target genes of each miRNA were altered significantly upon transfection of specific miRNA mimics in the C4–2 CRPC cell line, which was consistent with our pathway analysis results. Finally, we hypothesized that miR-218, miR-145, miR-197, miR-149, miR-122, and let-7b may contribute to the development of CRPC through the influence of Ras, Rho proteins, and the SCF complex. Further investigation is needed to verify the functions of the identified novel pathways in CRPC development.     

Invasion front-specific expression and prognostic significance of microRNA in colorectal liver metastases

The tumor edge of colorectal cancer and its adjacent peritumoral tissue is characterized by an invasion front-specific expression of genes that contribute to angiogenesis or epithelial-to-mesenchymal transition. Dysregulation of these genes has a strong impact on the invasion behavior of tumor cells. However, the invasion front-specific expression of microRNA (miRNA) still remains unclear. Therefore, the aim of the present study was to investigate miRNA expression patterns at the invasion front of colorectal liver metastases. Laser microdissection of colorectal liver metastases was performed to obtain separate tissue compartments from the tumor center, tumor invasion front, liver invasion front and pure liver parenchyma. Microarray expression analysis revealed 23 miRNA downregulated in samples from the tumor invasion front with respect to the same miRNA in the liver, the liver invasion front or the tumor center. By comparing samples from the liver invasion front with samples from pure liver parenchyma, the tumor invasion front and the tumor center, 13 miRNA were downregulated. By quantitative RT-PCR, we validated the liver invasion front-specific downregulation of miR-19b, miR-194, let-7b and miR-1275 and the tumor invasion front-specific downregulation of miR-143, miR- 145, let-7b and miR-638. Univariate analysis demonstrated that enhanced expression of miR-19b and miR-194 at the liver invasion front, and decreased expression of let-7 at the tumor invasion front, is an adverse prognostic marker of tumor recurrence and overall survival. In conclusion, the present study suggests that invasion front-specific downregulation of miRNA in colorectal liver metastases plays a pivotal role in tumor progression.     

结肠癌组织和癌旁组织miRNA表达谱研究

目的探讨结肠癌癌组织和癌旁组织中miRNA的表达差异,寻找潜在的结肠癌特异表达谱。方法miRNA表达芯片检测手术切除未发生转移的原位结肠癌组织和癌旁组织标本中miRNA表达水平,并采用Real-time PCR对差异表达的miRNA进行验证。结果miRNA表达芯片分析发现肿瘤细胞中24种miRNA表达下调,27种表达上调。miR-145、miR-143在癌组织中表达显著下调,miR-451在癌组织中表达显著上调,并被Real-time PCR方法进一步证实。结论结肠癌癌组织和癌旁组织中miRNA的表达存在差异,miR-145、miR-143在结肠癌组织中表达下调,miR-451表达上调,结肠癌组织具有特异miRNA表达谱,可作为结肠癌潜在诊断芯片进行开发。