MiR-148a Attenuates Paclitaxel Resistance of Hormone-refractory,Drug-resistant Prostate Cancer PC3 Cells by Regulating MSK1 Expression

MicroRNAs are involved in cancer pathogenesis and act as tumor suppressors or oncogenes. It has been recently reported that miR-148a expression is down-regulated in several types of cancer. The functional roles and target genes of miR-148a in prostate cancer, however, remain unknown. In this report, we showed that miR-148a expression levels were lower in PC3 and DU145 hormone-refractory prostate cancer cells in comparison to PrEC normal human prostate epithelial cells and LNCaP hormone-sensitive prostate cancer cells. Transfection with miR-148a precursor inhibited cell growth, and cell migration and invasion, and increased the sensitivity to anti-cancer drug paclitaxel in PC3 cells. Computer-aided algorithms predicted mitogen- and stress-activated protein kinase, MSK1, as a potential target of miR-148a. Indeed, miR-148a overexpression decreased expression of MSK1. Using luciferase reporter assays, we identified MSK1 as a direct target of miR-148a. Suppression of MSK1 expression by siRNA, however, showed little or no effects on malignant phenotypes of PC3 cells. In PC3PR cells, a paclitaxel-resistant cell line established from PC3 cells, miR-148a inhibited cell growth, and cell migration and invasion, and also attenuated the resistance to paclitaxel. MiR-148a reduced MSK1 expression by directly targeting its 3′-UTR in PC3PR cells. Furthermore, MSK1 knockdown reduced paclitaxel-resistance of PC3PR cells, indicating that miR-148a attenuates paclitaxel-resistance of hormone-refractory, drug-resistant PC3PR cells in part by regulating MSK1 expression. Our findings suggest that miR-148a plays multiple roles as a tumor suppressor and can be a promising therapeutic target for hormone-refractory prostate cancer especially for drug-resistant prostate cancer.     

miR-888 is an expressed prostatic secretions-derived microRNA that promotes prostate cell growth and migration

microRNAs (miRNAs) are a growing class of small non-coding RNAs that exhibit widespread dysregulation in prostate cancer. We profiled miRNA expression in syngeneic human prostate cancer cell lines that differed in their metastatic potential in order to determine their role in aggressive prostate cancer. miR-888 was the most differentially expressed miRNA observed in human metastatic PC3-ML cells relative to non-invasive PC3-N cells, and its levels were higher in primary prostate tumors from cancer patients, particularly those with seminal vesicle invasion. We also examined a novel miRNA-based biomarker source called expressed prostatic secretions in urine (EPS urine) for miR-888 expression and found that its levels were preferentially elevated in prostate cancer patients with high-grade disease. These expression studies indicated a correlation for miR-888 in disease progression. We next tested how miR-888 regulated cancer-related pathways in vitro using human prostate cancer cell lines. Overexpression of miR-888 increased proliferation and migration, and conversely inhibition of miR-888 activity blocked these processes. miR-888 also increased colony formation in PC3-N and LNCaP cells, supporting an oncogenic role for this miRNA in the prostate. Our data indicates that miR-888 functions to promote prostate cancer progression and can suppress protein levels of the tumor suppressor genes RBL1 and SMAD4. This miRNA holds promise as a diagnostic tool using an innovative prostatic fluid source as well as a therapeutic target for aggressive prostate cancer.     

Genistein Up-Regulates Tumor Suppressor MicroRNA-574-3p in Prostate Cancer

Genistein has been shown to inhibit cancers both in vitro and in vivo, by altering the expression of several microRNAs (miRNAs). In this study, we focused on tumor suppressor miRNAs regulated by genistein and investigated their function in prostate cancer (PCa) and target pathways. Using miRNA microarray analysis and real-time RT-PCR we observed that miR-574-3p was significantly up-regulated in PCa cells treated with genistein compared with vehicle control. The expression of miR-574-3p was significantly lower in PCa cell lines and clinical PCa tissues compared with normal prostate cells (RWPE-1) and adjacent normal tissues. Low expression level of miR-574-3p was correlated with advanced tumor stage and higher Gleason score in PCa specimens. Re-expression of miR-574-3p in PCa cells significantly inhibited cell proliferation, migration and invasion in vitro and in vivo. miR-574-3p restoration induced apoptosis through reducing Bcl-xL and activating caspase-9 and caspase-3. Using GeneCodis software analysis, several pathways affected by miR-574-3p were identified, such as ‘Pathways in cancer’, ‘Jak-STAT signaling pathway’, and ‘Wnt signaling pathway’. Luciferase reporter assays demonstrated that miR-574-3p directly binds to the 3′ UTR of several target genes (such as RAC1, EGFR and EP300) that are components of ‘Pathways in cancer’. Quantitative real-time PCR and Western analysis showed that the mRNA and protein expression levels of the three target genes in PCa cells were markedly down-regulated with miR-574-3p. Loss-of-function studies demonstrated that the three target genes significantly affect cell proliferation, migration and invasion in PCa cell lines. Our results show that genistein up-regulates tumor suppressor miR-574-3p expression targeting several cell signaling pathways. These findings enhance understanding of how genistein regulates with miRNA in PCa.     

Modulation of miR-34a in curcumin-induced antiproliferation of prostate cancer cells

Curcumin is a phytochemical which exhibits significant inhibitory effect in multiple cancers including prostate cancer. MicroRNA-34a (miR-34a) was found to be a master tumor suppressor miRNA and regulated the growth of cancer cells. To date, however, the role of miR-34a in the anticancer action of curcumin against prostate cancer has been rarely reported. In the present study, we showed that curcumin altered the expression of cell cycle-related genes (cyclin D1, PCNA, and p21) and inhibited the proliferation of prostate cancer cells. Furthermore, we found that curcumin significantly upregulated the expression of miR-34a, along with the downregulated expression of β-catenin and c-myc in three prostate cancer cell lines. Inhibition of miR-34a activated β-catenin/c-myc axis, altered cell cycle-related genes expression and significantly suppressed the antiproliferation effect of curcumin in prostate cancer cells. Findings from this study revealed that miR-34a plays an important role in the antiproliferation effect of curcumin in prostate cancer.     

The miR-15a-miR-16-1 cluster controls prostate cancer by targeting multiple oncogenic activities

MicroRNAs (miRNAs) are noncoding small RNAs that repress protein translation by targeting specific messenger RNAs. miR-15a and miR-16-1 act as putative tumor suppressors by targeting the oncogene BCL2. These miRNAs form a cluster at the chromosomal region 13q14, which is frequently deleted in cancer. Here, we report that the miR-15a and miR-16-1 cluster targets CCND1 (encoding cyclin D1) and WNT3A, which promotes several tumorigenic features such as survival, proliferation and invasion. In cancer cells of advanced prostate tumors, the miR-15a and miR-16 level is significantly decreased, whereas the expression of BCL2, CCND1 and WNT3A is inversely upregulated. Delivery of antagomirs specific for miR-15a and miR-16 to normal mouse prostate results in marked hyperplasia, and knockdown of miR-15a and miR-16 promotes survival, proliferation and invasiveness of untransformed prostate cells, which become tumorigenic in immunodeficient NOD-SCID mice. Conversely, reconstitution of miR-15a and miR-16-1 expression results in growth arrest, apoptosis and marked regression of prostate tumor xenografts. Altogether, we propose that miR-15a and miR-16 act as tumor suppressor genes in prostate cancer through the control of cell survival, proliferation and invasion. These findings have therapeutic implications and may be exploited for future treatment of prostate cancer.     

MicroRNA-1280 Inhibits Invasion and Metastasis by Targeting ROCK1 in Bladder Cancer

MicroRNAs (miRNAs) are non-protein-coding sequences that can function as oncogenes or tumor suppressor genes. This study documents the tumor suppressor role of miR-1280 in bladder cancer. Quantitative real-time PCR and in situ hybridization analyses showed that miR-1280 is significantly down-regulated in bladder cancer cell lines and tumors compared to a non-malignant cell line or normal tissue samples. To decipher the functional significance of miR-1280 in bladder cancer, we ectopically over-expressed miR-1280 in bladder cancer cell lines. Over-expression of miR-1280 had antiproliferative effects and impaired colony formation of bladder cancer cell lines. FACS (fluorescence activated cell sorting) analysis revealed that re-expression of miR-1280 in bladder cancer cells induced G2-M cell cycle arrest and apoptosis. Our results demonstrate that miR-1280 inhibited migration and invasion of bladder cancer cell lines. miR-1280 also attenuated ROCK1 and RhoC protein expression. Luciferase reporter assays demonstrated that oncogene ROCK1 is a direct target of miR-1280 in bladder cancer. This study also indicates that miR-1280 may be of diagnostic and prognostic importance in bladder cancer. For instance, ROC analysis showed that miR-1280 expression can distinguish between malignant and normal bladder cancer cases and Kaplan-Meier analysis revealed that patients with miR-1280 high expression had higher overall survival compared to those with low miR-1280 expression. In conclusion, this is the first study to document that miR-1280 functions as a tumor suppressor by targeting oncogene ROCK1 to invasion/migration and metastasis. Various compounds are currently being used as ROCK1 inhibitors; therefore restoration of tumor suppressor miR-1280 might be therapeutically useful either alone or in combination with these compounds in the treatment of bladder cancer.     

miRNA profiling in colorectal cancer highlights miR-1 involvement in MET-dependent proliferation

Altered expression of miRNAs is associated with development and progression of various human cancers by regulating the translation of oncogenes and tumor suppressor genes. In colorectal cancer, these regulators complement the Vogelstein multistep model of pathogenesis and have the potential of becoming a novel class of tumor biomarkers and therapeutic targets. Using quantitative real-time PCR, we measured the expression of 621 mature miRNAs in 40 colorectal cancers and their paired normal tissues and identified 23 significantly deregulated miRNAs. We subsequently evaluated their association with clinical characteristics of the samples and presence of alterations in the molecular markers of colorectal cancer progression. Expression levels of miR-31 were correlated with CA19-9 and miR-18a, miR-21, and miR-31 were associated with mutations in APC gene. To investigate the downstream regulation of the differentially expressed miRNAs identified, we integrated putative mRNA target predictions with the results of a meta-analysis of seven public gene expression datasets of normal and tumor samples of colorectal cancer patients. Many of the colorectal cancer deregulated miRNAs computationally mapped to targets involved in pathways related to progression. Here one promising candidate pair (miR-1 and MET) was studied and functionally validated. We show that miR-1 can have a tumor suppressor function in colorectal cancer by directly downregulating MET oncogene both at RNA and protein level and that reexpression of miR-1 leads to MET-driven reduction of cell proliferation and motility, identifying the miR-1 downmodulation as one of the events that could enhance colorectal cancer progression.     

MicroRNA-490-5p inhibits proliferation of bladder cancer by targeting c-Fos

MicroRNAs (miRNAs) are non-protein-coding sequences that play a crucial role in tumorigenesis by negatively regulating gene expression. Here, we found that miR-490-5p is down-regulated in human bladder cancer tissue and cell lines compared to normal adjacent tissue and a non-malignant cell line. To better characterize the function of miR-490-5p in bladder cancer, we over-expressed miR-490-5p in bladder cancer cell lines with chemically synthesized mimics. Enforced expression of miR-490-5p in bladder cancer cells significantly inhibited the cell proliferation via G1-phase arrest. Further studies found the decreased c-Fos expression at both mRNA and protein levels and Luciferase reporter assays demonstrated that c-Fos is a direct target of miR-490-5p in bladder cancer. These findings indicate miR-490-5p to be a novel tumor suppressor of bladder cancer cell proliferation through targeting c-Fos.     

miR-126调控前列腺癌机制研究

miR-126通过靶向作用于表皮生长因子域7（EGFL7）、同源框A9（HOXA9）、胰岛素受体底物-1（11LS-1）、p85-B基因等,在转录后水平调控靶基因表达,在肿瘤形成中起重要作用。前列腺癌细胞中高表达miR,126,能明显下调VEGF—A、EGLF7、HOXA9、VCAM—1等与肿瘤生长、转移密切相关的蛋白分子。miR-126作为抑癌因子,在多种肿瘤中均下调。其抑癌作用及机制在肺癌、白血病、乳腺癌、宫颈癌等中均已得到证实。本课题拟对miR-126调控前列腺癌机制做一综述。     

miR-145靶向调控DAB2对前列腺癌PC3细胞迁移和侵袭能力的影响

已有研究表明, miR-145在多种肿瘤中低表达, 并与细胞增殖和转移相关。文章通过生物信息学分析并结合体外实验鉴定, 发现DAB2(Disabled homolog 2)为miR-145在肿瘤转移过程中累及的新靶点。DAB2一直被认为是一个重要的抑癌基因, 在多种肿瘤标本中表达低下。然而, 研究发现, 在具高侵袭能力的前列腺癌细胞株PC3中DAB2基因却呈较高水平表达。另外, 外源表达miR-145能显著下调 DAB2表达水平, 并抑制PC3细胞的迁移和侵袭能力, 且这种miR-145诱导的PC3细胞功能缺陷能被DAB2过表达修复。上述结果表明, miR-145能通过靶向调控DAB2而影响高侵袭前列腺癌细胞的迁移和侵袭能力。     

The Curcumin Analog EF24 Targets NF-κB and miRNA-21, and Has Potent Anticancer Activity In Vitro and In Vivo

EF24 is a curcumin analog that has improved anticancer activity over curcumin, but its therapeutic potential and mechanism of action is unknown, which is important to address as curcumin targets multiple signaling pathways. EF24 inhibits the NF-κB but not the JAK-STAT signaling pathway in DU145 human prostate cancer cells and B16 murine melanoma cells. EF24 induces apoptosis in these cells apparently by inhibiting miR-21 expression, and also enhances the expression of several miR-21 target genes, PTEN and PDCD4. EF24 treatment significantly suppressed the growth of DU145 prostate cancer xenografts in immunocompromised mice and resulted in tumor regression. EF24 enhanced the expression of the miR-21 target PTEN in DU145 tumor tissue, but suppressed the expression of markers of proliferating cells (cyclin D1 and Ki67). In syngeneic mice injected with B16 cells, EF24 treatment inhibited the formation of lung metastasis, prolonged animal survival, inhibited miR-21 expression and increased the expression of miR-21 target genes. Expression profiling of miRNAs regulated by EF24 in vitro and in vivo showed that the antitumor activity of EF24 reflected the enhanced expression of potential tumor suppressor miRNAs as well as the suppressed expression of oncogenic miRNAs, including miR-21. Taken together, our data suggest that EF24 is a potent anticancer agent and selectively targets NF-κB signaling and miRNA expression, indicating that EF24 has significant potential as a therapeutic agent in various cancers.     

miR-126 调控前列腺癌机制研究

miR-126通过靶向作用于表皮生长因子域7(EGFL7)、同源框A9(HOXA9)、胰岛素受体底物-1(IlLS-1)、p85-B基因等,在转录后水平调控靶基因表达,在肿瘤形成中起重要作用。前列腺癌细胞中高表达miR-126,能明显下调VEGF-A、EGLF7、HOXA9、VCAM-l等与肿瘤生长、转移密切相关的蛋白分子。miR-126作为抑癌因子,在多种肿瘤中均下调。其抑癌作用及机制在肺癌、白血病、乳腺癌、宫颈癌等中均已得到证实。本课题拟对miR-126调控前列腺癌机制做一综述。