451
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Glubb DM, Innocenti F. Mechanisms of genetic regulation in gene expression: examples from drug metabolizing enzymes and transporters. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2010; 3:299-313. [PMID: 20865777 DOI: 10.1002/wsbm.125] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Interindividual variability in the response to drug therapy is due, in part, to genetic mechanisms which influence the expression of genes involved with drug metabolism and transport. Genetic elements and processes such as DNA methylation, histone deacetylation, transcription factors, DNA sequence variants, and microRNAs (miRNAs) can impact at either the transcriptional or translational levels to modulate gene expression. Identification of such genetic regulators has greatly advanced in the last decade. Genome-wide analyses, using different types of approaches and methodologies, have uncovered many potential regulators of the expression of drug metabolizing enzymes and transporters. However, confirming the function of these putative regulators is necessary and requires further work in the laboratory, using techniques which are still evolving. It also still remains to be seen whether these findings have clinical implications for drug therapy but the realization of personalized medicine is a possible consequence of this research.
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Affiliation(s)
- Dylan M Glubb
- Department of Medicine, University of Chicago, Chicago, IL, USA
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452
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Yu D, dos Santos CO, Zhao G, Jiang J, Amigo JD, Khandros E, Dore LC, Yao Y, D'Souza J, Zhang Z, Ghaffari S, Choi J, Friend S, Tong W, Orange JS, Paw BH, Weiss MJ. miR-451 protects against erythroid oxidant stress by repressing 14-3-3zeta. Genes Dev 2010; 24:1620-33. [PMID: 20679398 DOI: 10.1101/gad.1942110] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The bicistronic microRNA (miRNA) locus miR-144/451 is highly expressed during erythrocyte development, although its physiological roles are poorly understood. We show that miR-144/451 ablation in mice causes mild erythrocyte instability and increased susceptibility to damage after exposure to oxidant drugs. This phenotype is deeply conserved, as miR-451 depletion synergizes with oxidant stress to cause profound anemia in zebrafish embryos. At least some protective activities of miR-451 stem from its ability to directly suppress production of 14-3-3zeta, a phospho-serine/threonine-binding protein that inhibits nuclear accumulation of transcription factor FoxO3, a positive regulator of erythroid anti-oxidant genes. Thus, in miR-144/451(-/-) erythroblasts, 14-3-3zeta accumulates, causing partial relocalization of FoxO3 from nucleus to cytoplasm with dampening of its transcriptional program, including anti-oxidant-encoding genes Cat and Gpx1. Supporting this mechanism, overexpression of 14-3-3zeta in erythroid cells and fibroblasts inhibits nuclear localization and activity of FoxO3. Moreover, shRNA suppression of 14-3-3zeta protects miR-144/451(-/-) erythrocytes against peroxide-induced destruction, and restores catalase activity. Our findings define a novel miRNA-regulated pathway that protects erythrocytes against oxidant stress, and, more generally, illustrate how a miRNA can influence gene expression by altering the activity of a key transcription factor.
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Affiliation(s)
- Duonan Yu
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
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453
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Wang Z, Li Y, Ahmad A, Azmi AS, Kong D, Banerjee S, Sarkar FH. Targeting miRNAs involved in cancer stem cell and EMT regulation: An emerging concept in overcoming drug resistance. Drug Resist Updat 2010; 13:109-18. [PMID: 20692200 PMCID: PMC2956795 DOI: 10.1016/j.drup.2010.07.001] [Citation(s) in RCA: 274] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 07/08/2010] [Accepted: 07/08/2010] [Indexed: 02/06/2023]
Abstract
Although chemotherapy is an important therapeutic strategy for cancer treatment, it fails to eliminate all tumor cells due to intrinsic or acquired drug resistance, which is the most common cause of tumor recurrence. Emerging evidence suggests an intricate role of cancer stem cells (CSCs) and epithelial-mesenchymal transition (EMT)-type cells in anticancer drug resistance. Recent studies also demonstrated that microRNAs (miRNAs) play critical roles in the regulation of drug resistance. Here we will discuss current knowledge regarding CSCs, EMT and the role of regulation by miRNAs in the context of drug resistance, tumor recurrence and metastasis. A better understanding of the molecular intricacies of drug-resistant cells will help to design novel therapeutic strategies by selective targeting of CSCs and EMT-phenotypic cells through alterations in the expression of specific miRNAs towards eradicating tumor recurrence and metastasis. A particular promising lead is the potential synergistic combination of natural compounds that affect critical miRNAs, such as curcumin or epigallocatechin-3-gallate (EGCG) with chemotherapeutic agents.
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Affiliation(s)
- Zhiwei Wang
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, School of Medicine, Detroit, MI 48201, USA
| | - Yiwei Li
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, School of Medicine, Detroit, MI 48201, USA
| | - Aamir Ahmad
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, School of Medicine, Detroit, MI 48201, USA
| | - Asfar S Azmi
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, School of Medicine, Detroit, MI 48201, USA
| | - Dejuan Kong
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, School of Medicine, Detroit, MI 48201, USA
| | - Sanjeev Banerjee
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, School of Medicine, Detroit, MI 48201, USA
| | - Fazlul H Sarkar
- Department of Pathology, Karmanos Cancer Institute, Wayne State University, School of Medicine, Detroit, MI 48201, USA
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454
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Napieralski R, Brünner N, Mengele K, Schmitt M. Emerging biomarkers in breast cancer care. Biomark Med 2010; 4:505-22. [DOI: 10.2217/bmm.10.73] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Currently, decision-making for breast cancer treatment in the clinical setting is mainly based on clinical data, histomorphological features of the tumor tissue and a few cancer biomarkers such as steroid hormone receptor status (estrogen and progesterone receptors) and oncoprotein HER2 status. Although various therapeutic options were introduced into the clinic in recent decades, with the objective of improving surgery, radiotherapy, biochemotherapy and chemotherapy, varying response of individual patients to certain types of therapy and therapy resistance is still a challenge in breast cancer care. Therefore, since breast cancer treatment should be based on individual features of the patient and her tumor, tailored therapy should be an option by integrating cancer biomarkers to define patients at risk and to reliably predict their course of the disease and/or response to cancer therapy. Recently, candidate-marker approaches and genome-wide transcriptomic and epigenetic screening of different breast cancer tissues and bodily fluids resulted in new promising biomarker panels, allowing breast cancer prognosis, prediction of therapy response and monitoring of therapy efficacy. These biomarkers are now subject of validation in prospective clinical trials.
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Affiliation(s)
- Rudolf Napieralski
- Clinical Research Unit, Department of Obstetrics & Gynecology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Germany
| | - Nils Brünner
- University of Copenhagen, Faculty of Life Sciences, Department of Veterinary Disease Biology, Ridebanevej 9, DK-1870 Frederiksberg C, Denmark
| | - Karin Mengele
- Clinical Research Unit, Department of Obstetrics & Gynecology, Klinikum rechts der Isar, Technische Universitaet Muenchen, Germany
| | - Manfred Schmitt
- Clinical Research Unit, Department of Obstetrics & Gynecology, Ismaninger Strasse 22, Klinikum rechts der Isar, Technische Universitaet Muenchen, D-81675 Munich, Germany
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455
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Kovalchuk O, Zemp FJ, Filkowski JN, Altamirano AM, Dickey JS, Jenkins-Baker G, Marino SA, Brenner DJ, Bonner WM, Sedelnikova OA. microRNAome changes in bystander three-dimensional human tissue models suggest priming of apoptotic pathways. Carcinogenesis 2010; 31:1882-8. [PMID: 20643754 DOI: 10.1093/carcin/bgq119] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The radiation-induced bystander effect (RIBE) is a phenomenon whereby unexposed cells exhibit molecular symptoms of stress exposure when adjacent or nearby cells are traversed by ionizing radiation (IR). Recent data suggest that RIBE may be epigenetically mediated by microRNAs (miRNAs), which are small regulatory molecules that target messenger RNA transcripts for translational inhibition. Here, we analyzed microRNAome changes in bystander tissues after α-particle microbeam irradiation of three-dimensional artificial human tissues using miRNA microarrays. Our results indicate that IR leads to a deregulation of miRNA expression in bystander tissues. We report that major bystander end points, including apoptosis, cell cycle deregulation and DNA hypomethylation, may be mediated by altered expression of miRNAs. Specifically, c-MYC-mediated upregulation of the miR-17 family was associated with decreased levels of E2F1 and RB1, suggesting a switch to a proliferative state in bystander tissues, while priming these cells for impending death signals. Upregulation of the miR-29 family resulted in decreased levels of its targets DNMT3a and MCL1, consequently affecting DNA methylation and apoptosis. Altered expression of miR-16 led to changes in expression of BCL2, suggesting modulation of apoptosis. Thus, our data clearly show that miRNAs play a profound role in the manifestation of late RIBE end points. In summary, this study creates a roadmap for understanding the role of microRNAome in RIBE and for developing novel RIBE biomarkers.
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Affiliation(s)
- Olga Kovalchuk
- Department of Biological Sciences, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, T1K 3M4 Canada.
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456
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Hummel R, Hussey DJ, Michael MZ, Haier J, Bruewer M, Senninger N, Watson DI. MiRNAs and their association with locoregional staging and survival following surgery for esophageal carcinoma. Ann Surg Oncol 2010; 18:253-60. [PMID: 20628822 DOI: 10.1245/s10434-010-1213-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2010] [Indexed: 12/18/2022]
Abstract
BACKGROUND Prognostic and staging information for esophageal cancer impacts clinical decision making. miRNAs, a newly discovered class of biomarkers and their expression might add additional information relevant to this. In this study we evaluated the expression of selected miRNAs and their relationship to tumor stage and survival in patients with locally advanced tumors following esophagectomy. MATERIALS AND METHODS A total of 43 individuals undergoing esophagectomy (without neoadjuvant therapy) for locally advanced but not metastatic (pT2/3; pN0/1) disease (22 adenocarcinoma [EAC], 21 squamous cell carcinoma [SCC]) were included in this study. Perioperative clinical and survival data were collected and managed on a database. The expression of miR-21, miR-106a, miR-148a, miR-205 in formalin-fixed paraffin-embedded specimens was evaluated by TaqMan qPCR assays. Expression was compared with clinicopathological features of the cancers and outcome. RESULTS In EAC, miR-148a expression levels were inversely associated with cancer differentiation. miR-21 expression levels were higher in SCC if distant lymph node metastases were present. miR-148a levels were lower when EAC was more proximally located, and miR-21 levels were lower when SCC was more proximal. miR-106a and miR-148a were lower in patients with SCC who developed recurrent disease or had a tumor-related death. CONCLUSIONS In patients with locally advanced esophageal squamous cell carcinoma, but not adenocarcinoma, alterations in the expression of miR-21 correlate with tumor location and lymph node status. Furthermore, miR-106a and miR-148a expression correlates with disease recurrence and tumor-related mortality. miRNA markers might inform the initial assessment of these patients, and predict those at higher risk of postsurgical recurrence.
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Affiliation(s)
- Richard Hummel
- Department of Surgery, Flinders University, Bedford Park, SA, Australia
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457
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Shi L, Chen J, Yang J, Pan T, Zhang S, Wang Z. MiR-21 protected human glioblastoma U87MG cells from chemotherapeutic drug temozolomide induced apoptosis by decreasing Bax/Bcl-2 ratio and caspase-3 activity. Brain Res 2010; 1352:255-64. [PMID: 20633539 DOI: 10.1016/j.brainres.2010.07.009] [Citation(s) in RCA: 256] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 06/27/2010] [Accepted: 07/05/2010] [Indexed: 10/19/2022]
Abstract
MicroRNAs (miRNAs) are small noncoding RNA molecules that regulate protein expression by cleaving or repressing the translation of target mRNAs. In mammal animals, their function mainly represses the target mRNAs transcripts via imperfectly complementary to the 3'UTR of target mRNAs. Several miRNAs have been recently reported to be involved in modulation of glioma development, especially some up-regulated miRNAs, such as microRNA-21 (miR-21), which has been found to function as an oncogene in cultured glioblastoma multiforme cells. Temozolomide (TMZ), an alkylating agent, is a promising chemotherapeutic agent for treating glioblastoma. However, resistance develops quickly and with high frequency. To explore the mechanism of resistance, we found that miR-21 could protect human glioblastoma U87MG cells from TMZ induced apoptosis. Our studies showed that TMZ markedly enhanced apoptosis in U87MG cells compared with untreated cells (P<0.05). However, over-express miR-21 in U87MG cells could significantly reduce TMZ-induced apoptosis (P<0.05). Pro-apoptotic Bax and anti-apoptotic Bcl-2 proteins are known to regulate the apoptosis of glioma cells. Bcl-2, resistance to induction of apoptosis, constitutes one major obstacle to chemotherapy in many cancer cells. Bax is shown to correlate with an increased survival of glioblastoma multiforme patients. Further research demonstrated that the mechanism was associated with a shift in Bax/Bcl-2 ratio and change in caspase-3 activity. Compared to control cells, cells treated with TMZ showed a significant increase in the Bax/Bcl-2 ratio and caspase-3 activity (P<0.01). However, such effect was partly prevented by treatment of cells with miR-21 overexpression before, which appeared to downregulate the Bax expression, upregulate the Bcl-2 expression and decrease caspase-3 activity. Taken together, these results suggested that over-express miR-21 could inhibit TMZ-induced apoptosis in U87MG cells, at least in part, by decreasing Bax/Bcl-2 ratio and caspase-3 activity, which highlighted the possibility of miR-21 overexpression in the clinical resistance to chemotherapeutic therapy of TMZ.
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Affiliation(s)
- Lei Shi
- Department of Neurosurgery, The First People's Hospital of Kunshan affiliated with Jiangsu University, Suzhou, PR China
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458
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MiR-27a modulates MDR1/P-glycoprotein expression by targeting HIPK2 in human ovarian cancer cells. Gynecol Oncol 2010; 119:125-30. [PMID: 20624637 DOI: 10.1016/j.ygyno.2010.06.004] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2010] [Revised: 06/02/2010] [Accepted: 06/04/2010] [Indexed: 12/11/2022]
Abstract
OBJECTIVE MicroRNAs (miRNAs) are non-coding, single-stranded small RNAs that regulate gene expression negatively, which is involved in fundamental cellular processes and the initiation, development and progression of human cancer. In this study, we investigated the role of miR-27a in the development of drug resistance in ovarian cancer cells. METHODS Expression of miR-27a in ovarian cancer cell lines A2780 and A2780/Taxol were detected by stem-loop real-time PCR. A2780 and A2780/Taxol cells were transfected with the mimics or inhibitors of miR-27a or negative control RNA (NC) by Lipofectamine 2000. The expression levels of MDR1 mRNA, P-glycoprotein (P-gp) and Homeodomain-interacting protein kinase-2 (HIPK2) proteins were assessed by real-time PCR and western blot respectively. Drug sensitivity was analyzed by MTT assay while apoptosis and the fluorescence intensity of intracellular Rhodamine 123 (Rh-123) were measured by FACS. RESULTS The expression levels of miR-27a and P-gp were up-regulated in paclitaxel-resistant ovarian cancer cell line A2780/Taxol as compared with its parental line A2780. Transfection of A2780/Taxol cells with the inhibitors of miR-27a decreased the expression of MDR1 mRNA and P-gp protein, increased HIPK2 protein expression, enhanced the sensitivity of A2780/taxol cells to paclitaxel, increased paclitaxel-induced apoptosis and the fluorescence intensity of intracellular Rh-123. Expression of MDR1 mRNA was increased while the sensitivity to paclitaxel was decreased in A2780 cells management with the mimics of miR-27a. CONCLUSIONS The deregulation of miR-27a may be involved in the development of drug resistance, regulating the expression of MDR1/P-gp, at least in part, by targeting HIPK2 in ovarian cancer cells.
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459
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Suzuki HI, Miyazono K. Dynamics of microRNA biogenesis: crosstalk between p53 network and microRNA processing pathway. J Mol Med (Berl) 2010; 88:1085-94. [PMID: 20614100 DOI: 10.1007/s00109-010-0650-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Revised: 06/17/2010] [Accepted: 06/24/2010] [Indexed: 12/12/2022]
Abstract
MicroRNAs (miRNAs) are pivotal regulators involved in various biological functions through the post-transcriptional regulation of gene expression. Alterations of miRNA expression and function contribute to both physiological and pathological processes such as development and cancer. While their roles have been attracting more attention in connection with tumor development, the mechanisms regulating miRNA biogenesis have not been well understood. Accumulating evidences have revealed the dynamic regulation of miRNA biosynthesis by several regulatory factors and demonstrated the complexity of miRNA-mediated gene regulation. In addition, several reports showed the interplay between the p53 tumor suppressor network and the miRNA-mediated gene regulatory system. We recently found that p53 modulates miRNA maturation at the processing step of primary miRNA transcripts, unraveling a novel function of p53. Here, we review the recent understanding of functional links between miRNA biogenesis and intracellular signaling pathways, with particular focus on the crosstalk between the p53 network and the miRNA biogenesis machinery. Further characterization of controlling elements for miRNA production and activity would provide important insights for a comprehensive understanding of the miRNA function in health and disease.
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Affiliation(s)
- Hiroshi I Suzuki
- Department of Molecular Pathology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
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460
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Calissano M, Latchman DS. Cell-specific regulation of the pro-survival Brn-3b transcription factor by microRNAs. Mol Cell Neurosci 2010; 45:317-23. [PMID: 20609388 DOI: 10.1016/j.mcn.2010.06.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 06/03/2010] [Accepted: 06/24/2010] [Indexed: 11/27/2022] Open
Abstract
We have previously shown that the Brn-3b transcription factor is subjected to post-transcriptional gene regulation by specific microRNAs (mir-23 and mir-214) in the ND7 and SHSY-5Y neuronal cell lines (Calissano et al., 2007). As Brn-3b plays an essential role in the survival of retinal ganglion cells in the rat (Erkman et al., 1996; Gan et al., 1996; Gan et al., 1999; Erkman et al., 2000), we wanted to investigate whether mir-23 and mir-214 are expressed and target Brn-3b mRNA in a retinal ganglion cell line (RGC-5) thus potentially killing the cells expressing it. Here we show that, possibly due to its pro-survival role, Brn-3b is protected from degradation by microRNAs in RGC-5 cells in contrast to its fate in other cell types. This seems to be accomplished by i) the lack of expression of one of the two microRNAs targeting its 3'UTR and by ii) the requirement of at least two distinct microRNAs to mediate its down-regulation in retinal ganglion cells. We speculate that this mechanism could have a widespread role in the regulation of mRNAs encoding for essential proteins.
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Affiliation(s)
- Mattia Calissano
- Medical Molecular Biology Unit, Institute of Child Health, University College London, 30 Guilford Street, WC1N 1EH London, UK.
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461
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Devaney E, Winter AD, Britton C. microRNAs: a role in drug resistance in parasitic nematodes? Trends Parasitol 2010; 26:428-33. [PMID: 20541972 PMCID: PMC2930248 DOI: 10.1016/j.pt.2010.05.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 05/17/2010] [Accepted: 05/18/2010] [Indexed: 12/19/2022]
Abstract
Drug resistance in parasitic nematodes is an increasing problem worldwide, with resistance reported to all three commonly used classes of anthelmintics. Most studies to date have sought to correlate the resistant phenotype with genotypic changes in putative target molecules. Although this approach has identified mutations in several relevant genes, resistance might result from a complex interaction of different factors. Here we propose an alternative mechanism underlying the development of drug resistance based on functional differences in microRNA activity in resistant parasites. microRNAs play an important role in resistance to chemotherapeutic agents in many tumour cells and here we discuss whether they might also be involved in anthelmintic resistance in parasitic nematodes.
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Affiliation(s)
- Eileen Devaney
- Parasitology Group, Division of Veterinary Infection and Immunity, Institute for Comparative Medicine, School of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK.
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462
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Koturbash I, Zemp FJ, Pogribny I, Kovalchuk O. Small molecules with big effects: the role of the microRNAome in cancer and carcinogenesis. Mutat Res 2010; 722:94-105. [PMID: 20472093 DOI: 10.1016/j.mrgentox.2010.05.006] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Accepted: 05/08/2010] [Indexed: 12/17/2022]
Abstract
Small non-coding RNAs-microRNAs, are potent negative regulators of gene expression. MicroRNAs are involved in multiple biological processes, metabolic regulation, including cell proliferation, differentiation, and programmed cell death. Since the dysregulation of these processes is a hallmark of cancer, microRNAs can be viewed as major contributors to the pathogenesis of cancer, including initiation and progression of cancer. This review focuses on microRNA biogenesis and function, and their role in cancer, metastasis, drug resistance, and tumorigenesis.
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Affiliation(s)
- Igor Koturbash
- Department of Biological Sciences, University of Lethbridge, AB, Canada
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463
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Abstract
Chemotherapy is the preferred treatment for malignancies. However, a successful long-term use of chemotherapy is often prevented by the development of drug resistance. Many mechanisms such as gene mutation, DNA methylation and histone modification have important roles in the resistance of cancer cells to chemotherapeutic agents. Climent suggested miR-125b was involved in the development of drug resistance by microRNA (miRNA) dysregulation. miRNAs are endogenously expressed small non-coding RNAs, which are evolutionarily conserved and function as regulators of gene expression. Much effort has been exerted in analyzing the role of miRNAs in the development of drug resistance in a variety of malignancies. Several research groups have shown that the expressions of miRNAs in chemoresistant cancer cells and their parental chemosensitive ones are different. The molecular targets and mechanisms of chemosensitivity and chemoresistance are also elucidated. This article reviews the functions of miRNAs in the development of drug resistance.
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464
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Liu H, Brannon AR, Reddy AR, Alexe G, Seiler MW, Arreola A, Oza JH, Yao M, Juan D, Liou LS, Ganesan S, Levine AJ, Rathmell WK, Bhanot GV. Identifying mRNA targets of microRNA dysregulated in cancer: with application to clear cell Renal Cell Carcinoma. BMC SYSTEMS BIOLOGY 2010; 4:51. [PMID: 20420713 PMCID: PMC2876063 DOI: 10.1186/1752-0509-4-51] [Citation(s) in RCA: 201] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Accepted: 04/27/2010] [Indexed: 12/19/2022]
Abstract
BACKGROUND MicroRNA regulate mRNA levels in a tissue specific way, either by inducing degradation of the transcript or by inhibiting translation or transcription. Putative mRNA targets of microRNA identified from seed sequence matches are available in many databases. However, such matches have a high false positive rate and cannot identify tissue specificity of regulation. RESULTS We describe a simple method to identify direct mRNA targets of microRNA dysregulated in cancers from expression level measurements in patient matched tumor/normal samples. The word "direct" is used here in a strict sense to: a) represent mRNA which have an exact seed sequence match to the microRNA in their 3'UTR, b) the seed sequence match is strictly conserved across mouse, human, rat and dog genomes, c) the mRNA and microRNA expression levels can distinguish tumor from normal with high significance and d) the microRNA/mRNA expression levels are strongly and significantly anti-correlated in tumor and/or normal samples. We apply and validate the method using clear cell Renal Cell Carcinoma (ccRCC) and matched normal kidney samples, limiting our analysis to mRNA targets which undergo degradation of the mRNA transcript because of a perfect seed sequence match. Dysregulated microRNA and mRNA are first identified by comparing their expression levels in tumor vs normal samples. Putative dysregulated microRNA/mRNA pairs are identified from these using seed sequence matches, requiring that the seed sequence be conserved in human/dog/rat/mouse genomes. These are further pruned by requiring a strong anti-correlation signature in tumor and/or normal samples. The method revealed many new regulations in ccRCC. For instance, loss of miR-149, miR-200c and mir-141 causes gain of function of oncogenes (KCNMA1, LOX), VEGFA and SEMA6A respectively and increased levels of miR-142-3p, miR-185, mir-34a, miR-224, miR-21 cause loss of function of tumor suppressors LRRC2, PTPN13, SFRP1, ERBB4, and (SLC12A1, TCF21) respectively. We also found strong anti-correlation between VEGFA and the miR-200 family of microRNA: miR-200a*, 200b, 200c and miR-141. Several identified microRNA/mRNA pairs were validated on an independent set of matched ccRCC/normal samples. The regulation of SEMA6A by miR-141 was verified by a transfection assay. CONCLUSIONS We describe a simple and reliable method to identify direct gene targets of microRNA in any cancer. The constraints we impose (strong dysregulation signature for microRNA and mRNA levels between tumor/normal samples, evolutionary conservation of seed sequence and strong anti-correlation of expression levels) remove spurious matches and identify a subset of robust, tissue specific, functional mRNA targets of dysregulated microRNA.
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Affiliation(s)
- Huiqing Liu
- BioMaPS Institute, Rutgers University, Piscataway, NJ 08854, USA
- Current address: Bioinformatics, Centocor R&D Inc, 145 King of Prussia Road, Radnor, PA 19087, USA
| | - Angela R Brannon
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Anupama R Reddy
- BioMaPS Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Gabriela Alexe
- Broad Institute of MIT and Harvard, 7 Cambridge Center, MA, 02142, USA
| | - Michael W Seiler
- BioMaPS Institute, Rutgers University, Piscataway, NJ 08854, USA
| | - Alexandra Arreola
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Jay H Oza
- Cancer Institute of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ 08903, USA
| | - Ming Yao
- Cancer Institute of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ 08903, USA
| | - David Juan
- Department of Pathology, Boston University Medical School, Boston, MA 02118, USA
| | - Louis S Liou
- Department of Pathology, Boston University Medical School, Boston, MA 02118, USA
- Cambridge Health Alliance, Harvard Medical School, Cambridge MA 02139, USA
| | - Shridar Ganesan
- Cancer Institute of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ 08903, USA
| | - Arnold J Levine
- Simons Center for Systems Biology, Institute for Advanced Study, Princeton, NJ 08540, USA
| | - WK Rathmell
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
- Departments of Medicine and Genetics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Gyan V Bhanot
- BioMaPS Institute, Rutgers University, Piscataway, NJ 08854, USA
- Cancer Institute of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ 08903, USA
- Simons Center for Systems Biology, Institute for Advanced Study, Princeton, NJ 08540, USA
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
- Department of Physics, Rutgers University, Piscataway, NJ 08854, USA
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465
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Implication of microRNAs in drug resistance for designing novel cancer therapy. Drug Resist Updat 2010; 13:57-66. [PMID: 20236855 DOI: 10.1016/j.drup.2010.02.001] [Citation(s) in RCA: 159] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2010] [Revised: 02/21/2010] [Accepted: 02/22/2010] [Indexed: 12/19/2022]
Abstract
Recently, microRNAs (miRNAs) have received increasing attention in the field of cancer research. miRNAs play important roles in many normal biological processes; however, the aberrant miRNA expression and its correlation with the development and progression of cancers is an emerging field. Therefore, miRNAs could be used as biomarkers for diagnosis of cancer and prediction of prognosis. Importantly, some miRNAs could regulate the formation of cancer stem cells and the acquisition of epithelial-mesenchymal transition, which are critically associated with drug resistance. Moreover, some miRNAs could target genes related to drug sensitivity, resulting in the altered sensitivity of cancer cells to anti-cancer drugs. Emerging evidences have also shown that knock-down or re-expression of specific miRNAs by synthetic anti-sense oligonucleotides or pre-miRNAs could induce drug sensitivity, leading to increased inhibition of cancer cell growth, invasion, and metastasis. More importantly, recent studies have shown that natural agents including isoflavone, 3,3'-diindolylmethane, and (-)-epigallocatechin-3-gallate altered miRNA expression profiles, leading to an increased sensitivity of cancer cells to conventional therapeutics. These emerging results suggest that specific targeting of miRNAs by different approaches could open new avenues for cancer treatment through overcoming drug resistance and thereby improve the outcome of cancer therapy.
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466
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Yoon S, Kim TH, Natarajan A, Wang SS, Choi J, Wu J, Zern MA, Venugopal SK. Acute liver injury upregulates microRNA-491-5p in mice, and its overexpression sensitizes Hep G2 cells for tumour necrosis factor-alpha-induced apoptosis. Liver Int 2010; 30:376-87. [PMID: 20015148 DOI: 10.1111/j.1478-3231.2009.02181.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND MicroRNAs (miRNAs) have emerged as novel genetic regulators of cell functions such as proliferation, apoptosis and cancer. AIMS The aim of this study was to evaluate the role of a specific miRNA in modulating hepatic cell functions. METHODS C57Bl/6 mice were administered anti-fas receptor antibodies to induce liver cell apoptosis. miRNAs were purified from the liver tissue and evaluated using an miRNA microarray. The role of miRNA-491_5p, which was overexpressed in the model, in modulating hepatic cell functions was evaluated. miRNA-491_5p was overexpressed in Hep G2 cells, followed by the addition of tumour necrosis factor (TNF)-alpha, and induction of apoptosis as well as genes involved in apoptosis pathways were evaluated. The effect of miRNA-491_5p target genes on apoptosis was also analysed by inhibiting their expression by siRNA-induced gene silencing. RESULTS Upregulation of miRNA-491_5p was found in a high-dose anti-fas receptor antibody group. Overexpression of microRNA-491_5p sensitized Hep G2 cells for TNF-alpha-induced apoptosis, and also caused an inhibition of alpha-fetoprotein, (AFP), heat shock protein-90 (hsp-90) and nuclear factor-kappaB (NF-kappaB). Overexpression of miRNA-491_5p or inhibition of AFP and hsp-90 resulted in an increased apoptosis in TNF-alpha-treated Hep G2 cells. CONCLUSIONS One of the miRNAs that is associated with the acute liver injury mouse model, miRNA-491_5p, sensitizes Hep G2 cells for TNF-alpha-induced apoptosis, at least in part, by inhibiting AFP, hsp-90 and NF-kappaB.
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Affiliation(s)
- Sangjeong Yoon
- Department of Internal Medicine: Transplant Research Program, University of California Davis Medical Center, Sacramento, CA 95817, USA
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467
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Masri S, Phung S, Wang X, Chen S. Molecular characterization of aromatase inhibitor-resistant, tamoxifen-resistant and LTEDaro cell lines. J Steroid Biochem Mol Biol 2010; 118:277-82. [PMID: 19897035 PMCID: PMC2836255 DOI: 10.1016/j.jsbmb.2009.10.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Accepted: 10/27/2009] [Indexed: 01/07/2023]
Abstract
To determine potential genes involved in mediating resistance to aromatase inhibitors (AIs), a microarray study was performed using MCF-7aro (aromatase overexpressing) cells that are resistant to letrozole (T+LET R), anastrozole (T+ANA R) and exemestane (T+EXE R), as well as LTEDaro and tamoxifen-resistant (T+TAM R) lines for comparison. Based on hierarchical clustering, estrogen-responsive genes were found to be differentially expressed in AI-resistant lines versus LTEDaro and T+TAM R. Additional genome-wide analysis showed that gene expression profiles of the non-steroidal AI-resistant lines were most closely correlated and that T+EXE R lines exhibit differing profiles. Also, LTEDaro and T+TAM R lines are inherently different from expression profiles of AI-resistant lines. Further characterization of these resistant lines revealed that T+LET R, T+ANA R and LTEDaro cells contain a constitutively active estrogen receptor alpha (ERalpha) that does not require the ligand estrogen for activation. Ligand-independent activation of ERalpha does not activate identical estrogen-responsive gene profiles in AI-resistant lines as in LTEDaro lines, thereby establishing differing mechanisms of resistance. This ligand-independent activation of ER was not observed in the parental cell lines MCF-7aro, T+EXE R or T+TAM R cells. Based on the steroidal structure of EXE, our laboratory has shown that this AI has weak estrogen-like properties, and that EXE resistance involves an ER-dependent crosstalk with EGFR growth factor signaling. Recent studies in our laboratory pertaining to pre-clinical models of AI treatment revealed that intermittent use of EXE delays the onset of acquired resistance in comparison to continuous treatment. Specific molecular mechanisms involved in intermittent use of EXE are currently being explored, based on microarray gene expression profiling. Lastly, our laboratory has initiated a study of microRNAs and their potential role in regulating target genes involved in AI-resistance. Overall, we propose a model of acquired resistance that progresses from hormone-dependence (T+TAM R and T+EXE R) to hormone-independence (T+LET R and T+ANA R), eventually resulting in hormone-independence that does not rely on conventional ER signaling (LTEDaro).
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Affiliation(s)
- Selma Masri
- Division of Tumor Cell Biology, Beckman Research Institute of the City of Hope, Duarte, CA, USA
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468
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Hui ABY, Lenarduzzi M, Krushel T, Waldron L, Pintilie M, Shi W, Perez-Ordonez B, Jurisica I, O'Sullivan B, Waldron J, Gullane P, Cummings B, Liu FF. Comprehensive MicroRNA profiling for head and neck squamous cell carcinomas. Clin Cancer Res 2010; 16:1129-39. [PMID: 20145181 DOI: 10.1158/1078-0432.ccr-09-2166] [Citation(s) in RCA: 294] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The objective of this study is to investigate the significance of microRNAs (miRNA) in patients with locally advanced head and neck squamous cell carcinoma (HNSCC). EXPERIMENTAL DESIGN A global miRNA profiling was done on 51 formalin-fixed archival HNSCC samples using quantitative reverse transcription-PCR approach, correlated with patients' clinical parameters. Functional characterization of HNSCC-associated miRNAs was conducted on three HNSCC cell lines. Cell viability and proliferation were investigated using MTS and clonogenic assays, respectively; cell cycle analyses were assessed using flow cytometry. RESULTS Thirty-eight of the 117 (33%) consistently detected miRNAs were significantly differentially expressed between malignant versus normal tissues. Concordant with previous reports, overexpression of miR-21, miR-155, let-7i, and miR-142-3p and underexpression of miR-125b and miR-375 were detected. Upregulation of miR-423, miR-106b, miR-20a, and miR-16 as well as downregulation of miR-10a were newly observed. Exogenous overexpression of miR-375 in HNSCC cell lines reduced proliferation and clonogenicity and increased cells in sub-G(1). Similar cellular effects were observed in knockdown studies of the miR-106b-25 cluster but with accumulation of cells in G(1) arrest. No major difference was detected in miRNA profiles among laryngeal, oropharyngeal, or hypopharyngeal cancers. miR-451 was found to be the only significantly overexpressed miRNA by 4.7-fold between nonrelapsed and relapsed patients. CONCLUSION We have identified a group of aberrantly expressed miRNAs in HNSCC and showed that underexpression of miR-375 and overexpression of miR-106b-25 cluster might play oncogenic roles in this disease. Further detailed examinations of miRNAs will provide opportunities to dissect the complex molecular abnormalities driving HNSCC progression.
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Affiliation(s)
- Angela B Y Hui
- Division of Applied Molecular Oncology, Ontario Cancer Institute, University of Toronto, Toronto, Ontario, Canada
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Ren Y, Zhou X, Mei M, Yuan XB, Han L, Wang GX, Jia ZF, Xu P, Pu PY, Kang CS. MicroRNA-21 inhibitor sensitizes human glioblastoma cells U251 (PTEN-mutant) and LN229 (PTEN-wild type) to taxol. BMC Cancer 2010; 10:27. [PMID: 20113523 PMCID: PMC2824710 DOI: 10.1186/1471-2407-10-27] [Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Accepted: 01/31/2010] [Indexed: 01/04/2023] Open
Abstract
Background Substantial data indicate that the oncogene microRNA 21 (miR-21) is significantly elevated in glioblastoma multiforme (GBM) and regulates multiple genes associated with cancer cell proliferation, apoptosis, and invasiveness. Thus, miR-21 can theoretically become a target to enhance the chemotherapeutic effect in cancer therapy. So far, the effect of downregulating miR-21 to enhance the chemotherapeutic effect to taxol has not been studied in human GBM. Methods Human glioblastoma U251 (PTEN-mutant) and LN229 (PTEN wild-type) cells were treated with taxol and the miR-21 inhibitor (in a poly (amidoamine) (PAMAM) dendrimer), alone or in combination. The 50% inhibitory concentration and cell viability were determined by the MTT assay. The mechanism between the miR-21 inhibitor and the anticancer drug taxol was analyzed using the Zheng-Jun Jin method. Annexin V/PI staining was performed, and apoptosis and the cell cycle were evaluated by flow cytometry analysis. Expression of miR-21 was investigated by RT-PCR, and western blotting was performed to evaluate malignancy related protein alteration. Results IC(50) values were dramatically decreased in cells treated with miR-21 inhibitor combine with taxol, to a greater extent than those treated with taxol alone. Furthermore, the miR-21 inhibitor significantly enhanced apoptosis in both U251 cells and LN229 cells, and cell invasiveness was obviously weakened. Interestingly, the above data suggested that in both the PTEN mutant and the wild-type GBM cells, miR-21 blockage increased the chemosensitivity to taxol. It is worth noting that the miR-21 inhibitor additively interacted with taxol on U251cells and synergistically on LN229 cells. Thus, the miR-21 inhibitor might interrupt the activity of EGFR pathways, independently of PTEN status. Meanwhile, the expression of STAT3 and p-STAT3 decreased to relatively low levels after miR-21 inhibitor and taxol treatment. The data strongly suggested that a regulatory loop between miR-21 and STAT3 might provide an insight into the mechanism of modulating EGFR/STAT3 signaling. Conclusions Taken together, the miR-21 inhibitor could enhance the chemo-sensitivity of human glioblastoma cells to taxol. A combination of miR-21 inhibitor and taxol could be an effective therapeutic strategy for controlling the growth of GBM by inhibiting STAT3 expression and phosphorylation.
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Affiliation(s)
- Yu Ren
- Laboratory of Neuro-oncology, Tianjin Neurological Institute, Tianjin, PR China
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470
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To KKW, Robey RW, Knutsen T, Zhan Z, Ried T, Bates SE. Escape from hsa-miR-519c enables drug-resistant cells to maintain high expression of ABCG2. Mol Cancer Ther 2010; 8:2959-68. [PMID: 19825807 DOI: 10.1158/1535-7163.mct-09-0292] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Overexpression of ABCG2 has been reported in cell lines selected for drug resistance and it is widely believed to be important in the clinical pharmacology of anticancer drugs. We and others have previously identified and validated two microRNAs (miRNA; hsa-miR-519c and hsa-miR-520h) targeting ABCG2. In this study, the shortening of the ABCG2 3' untranslated region (3'UTR) was found to be a common phenomenon in several ABCG2-overexpressing resistant cell lines, which as a result removes the hsa-miR-519c binding site and its repressive effects on mRNA stability and translation blockade, thereby contributing to drug resistance. On the other hand, reduced expression of hsa-miR-520h, previously thought to have allowed ABCG2 overexpression, was found to be caused by the sequestering of the miRNA by the highly expressed ABCG2. In drug-sensitive cells, inhibitors against hsa-miR-519c and hsa-miR-520h could augment the cytotoxic effect of mitoxantrone, suggesting a substantial role for both miRNAs in controlling ABCG2 level and thereby anticancer drug response. However, in drug-resistant cells, altering the levels of the two miRNAs did not have any effect on sensitivity to mitoxantrone. Taken together, these studies suggest that in ABCG2-overexpressing drug-resistant cells, hsa-miR-519c is unable to affect ABCG2 expression because the mRNA lacks its binding site, whereas hsa-miR-520h is sequestered and unable to limit ABCG2 expression. Given the recent observation that a truncated 3'UTR is also observed in ABCG2-overexpressing human embryonic stem cells, our results in drug-resistant cell lines suggest that 3'UTR truncation is a relatively common mechanism of ABCG2 regulation.
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MESH Headings
- 3' Untranslated Regions/genetics
- ATP Binding Cassette Transporter, Subfamily G, Member 2
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- Cell Line, Tumor
- Chromosomes, Human/genetics
- Drug Resistance, Neoplasm/drug effects
- Drug Screening Assays, Antitumor
- Gene Expression Regulation, Neoplastic/drug effects
- Gene Rearrangement/drug effects
- Gene Silencing/drug effects
- Humans
- MicroRNAs/genetics
- MicroRNAs/metabolism
- Mitoxantrone/pharmacology
- Neoplasm Proteins/genetics
- Neoplasm Proteins/metabolism
- RNA Stability/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Sequence Analysis, DNA
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Affiliation(s)
- Kenneth K W To
- School of Pharmacy, The Chinese University of Hong Kong, Hong Kong, Hong Kong.
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471
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Wang PY, Li YJ, Zhang S, Li ZL, Yue Z, Xie N, Xie SY. Regulating A549 cells growth by ASO inhibiting miRNA expression. Mol Cell Biochem 2010; 339:163-71. [PMID: 20049626 DOI: 10.1007/s11010-009-0380-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Accepted: 12/21/2009] [Indexed: 01/29/2023]
Abstract
MicroRNAs (miRNAs) have a profound impact on cell processes, including proliferation, apoptosis, and stress responses. We aimed to explore the role of antisense oligonucleotide (ASO) to induce proliferation or apoptosis of A549 cancer cells by inhibiting the expression of miRNAs. After A549/HBE/293T cells were treated with ASO, cells proliferation/apoptosis, and their relevant oncogenes/tumor suppressor genes were detected by light and electron microscopy, real-time PCR, enzyme-linked immunosorbent assay, etc. The results showed that ASO could inhibit the expression of miRNAs effectively. miR-16, miR-17, miR-34a-c, and miR-125 served as tumor suppressor miRNAs, while miR-20, miR-106, and miR-150 acted as oncogenic miRNAs. Our results also indicated that miR-16/34a-c, miR-17-5p, miR-125, miR-106, and miR-150 were the upstream factors, which could regulate the expression of BCL-2, E2F1, E2F3, RB1, and P53, respectively. After A549 cells treated with ASO for 24 h and different concentrations of anti-cancer drug (cisplatin or demethylcantharidin) were added into culture medium, the results indicated the percentage of alive cells in group treated with both ASO-106 (or ASO-150) and anti-cancer drug was lower than that in group treated with ASO, or anti-cancer drug, or both ASO-16 (or ASO-34a) and anti-cancer drug. In conclusion, ASO (specific to oncogenic miRNAs) could induce A549 cells apoptosis by inhibiting oncogenic miRNAs, and could increase chemotherapy sensitivity of A549 cells to anti-cancer drug, which holds great promise to lung cancer therapy.
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Affiliation(s)
- Ping-Yu Wang
- Department of Biochemistry and Molecular Biology, Institute of Medical Molecular Genetics, Binzhou Medical University, 264003 Yan Tai City, Shan Dong Province, People's Republic of China
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472
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Hummel R, Hussey DJ, Haier J. MicroRNAs: Predictors and modifiers of chemo- and radiotherapy in different tumour types. Eur J Cancer 2010; 46:298-311. [DOI: 10.1016/j.ejca.2009.10.027] [Citation(s) in RCA: 243] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Revised: 10/20/2009] [Accepted: 10/29/2009] [Indexed: 12/14/2022]
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473
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Ardelt W, Ardelt B, Darzynkiewicz Z. Ribonucleases as potential modalities in anticancer therapy. Eur J Pharmacol 2009; 625:181-9. [PMID: 19825371 PMCID: PMC2784098 DOI: 10.1016/j.ejphar.2009.06.067] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 05/20/2009] [Accepted: 06/08/2009] [Indexed: 11/24/2022]
Abstract
Antitumor ribonucleases are small (10-28 kDa) basic proteins. They were found among members of both, ribonuclease A and T1 superfamilies. Their cytotoxic properties are conferred by enzymatic activity, i.e., the ability to catalyze cleavages of phosphodiester bonds in RNA. They bind to negatively charged cell membrane, enter cells by endocytosis and translocate to cytosol where they evade mammalian protein ribonuclease inhibitor and degrade RNA. Here, we discuss structures, functions and mechanisms of antitumor activity of several cytotoxic ribonucleases with particular emphasis to the amphibian Onconase, the only enzyme of this class that reached clinical trials. Onconase is the smallest, very stable, less catalytically efficient and more cytotoxic than most RNase A homologues. Its cytostatic, cytotoxic and anticancer effects were extensively studied. It targets tRNA, rRNA, mRNA as well as the non-coding RNA (microRNAs). Numerous cancer lines are sensitive to Onconase; their treatment with 10-100 nM enzyme leads to suppression of cell cycle progression, predominantly through G(1), followed by apoptosis or cell senescence. Onconase also has anticancer properties in animal models. Many effects of this enzyme are consistent with the microRNAs, one of its critical targets. Onconase sensitizes cells to a variety of anticancer modalities and this property is of particular interest, suggesting its application as an adjunct to chemotherapy or radiotherapy in treatment of different tumors. Cytotoxic RNases as exemplified by Onconase represent a new class of antitumor agents, with an entirely different mechanism of action than the drugs currently used in the clinic. Further studies on animal models including human tumors grafted on severe combined immunodefficient (SCID) mice and clinical trials are needed to explore clinical potential of cytotoxic RNases.
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Affiliation(s)
- Wojciech Ardelt
- Brander Cancer Research Institute and Department of Pathology, New York Medical College, Valhalla, New York, USA.
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474
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Luzhna L, Kovalchuk O. Modulation of DNA methylation levels sensitizes doxorubicin-resistant breast adenocarcinoma cells to radiation-induced apoptosis. Biochem Biophys Res Commun 2009; 392:113-7. [PMID: 20034463 DOI: 10.1016/j.bbrc.2009.12.093] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2009] [Accepted: 12/16/2009] [Indexed: 11/26/2022]
Abstract
Chemoresistant tumors often fail to respond to other cytotoxic treatments such as radiation therapy. The mechanisms of chemo- and radiotherapy cross resistance are not fully understood and are believed to be epigenetic in nature. We hypothesize that MCF-7 cells and their doxorubicin-resistant variant MCF-7/DOX cells may exhibit different responses to ionizing radiation due to their dissimilar epigenetic status. Similar to previous studies, we found that MCF-7/DOX cells harbor much lower levels of global DNA methylation than MCF-7 cells. Furthermore, we found that MCF-7/DOX cells had lower background apoptosis levels and were less responsive to radiation than MCF-7 cells. Decreased radiation responsiveness correlated to significant global DNA hypomethylation in MCF-7/DOX cells. Here, for the first time, we show that the radiation resistance of MCF-7/DOX cells can be reversed by an epigenetic treatment--the application of methyl-donor SAM. SAM-mediated reversal of DNA methylation led to elevated radiation sensitivity in MCF-7/DOX cells. Contrarily, application of SAM on the radiation sensitive and higher methylated MCF-7 cells resulted in a decrease in their radiation responsiveness. This data suggests that a fine balance of DNA methylation is needed to insure proper radiation and drug responsiveness.
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Affiliation(s)
- Lidia Luzhna
- Department of Biological Sciences, University of Lethbridge, AB T1K3M4, Canada
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475
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Filkowski JN, Ilnytskyy Y, Tamminga J, Koturbash I, Golubov A, Bagnyukova T, Pogribny IP, Kovalchuk O. Hypomethylation and genome instability in the germline of exposed parents and their progeny is associated with altered miRNA expression. Carcinogenesis 2009; 31:1110-5. [PMID: 19959559 DOI: 10.1093/carcin/bgp300] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Recent studies suggest that transgenerational genome instability may be epigenetic in nature and mediated via altered DNA methylation and microRNAome. Here, we investigated the nature and mechanisms underlying the disruption of DNA methylation and microRNA expression status in the germline and progeny of exposed parents. We have found that paternal irradiation leads to upregulation of the miR-29 family in the exposed male germline, which causes decreased expression of de novo methyltransferase, DNA methyltransferase 3a, and profound hypomethylation of long interspersed nuclear elements 1 (LINE1) and short interspersed nuclear elements B2 (SINE B2). Epigenetic changes in the male germline further resulted in deleterious effects in the somatic thymus tissue from the progeny of exposed animals, including hypomethylation of LINE1 and SINE B2. Hypomethylation of LINE1 and SINE B2 in the thymus tissue from the progeny was associated with a significant decrease in the levels of lymphoid-specific helicase (LSH) that is crucial for the maintenance of methylation and silencing of repetitive elements. Furthermore, we noted a significant upregulation of miR-468 that targets LSH and leads to its decreased expression in thymus in the progeny of exposed parents. We suggest that miR-468-mediated suppression of LSH leads to aberrant methylation of LINE1 and SINE B2. In summary, altered microRNAome and hypomethylation of retroelements constitute deleterious effects that may significantly influence genome stability of the parental germline and consequently cause genome instability in the progeny.
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Affiliation(s)
- Jody N Filkowski
- Department of Biological Sciences, University of Lethbridge, 4401 University of Lethbridge, Alberta, Canada T1K 3M4
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476
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Abstract
Chemotherapy has been widely used in treatment of cancer, both as systemic therapy and as part of local treatment. Unfortunately, many kinds of cancer are still refractory to chemotherapy. The anticancer drug resistance mechanisms have been extensively explored, yet have not been fully characterized. Recent works have underlined the involvement of noncoding RNAs in cancer development, with several studies regarding their possible involvement in the evolution of drug resistance. MicroRNAs (miRNAs) are endogenous small noncoding RNAs (20-23 nucleotides) that negatively regulate the gene expressions at the post-transcriptional level by base pairing to the 3' untranslated region of target messenger RNAs. Evidence is emerging that particular microRNAs (miRNA) alterations are involved in the initiation and progression of human cancer. More recently, accumulating evidence is revealing an important role of miRNAs in anticancer drug resistance and miRNA expression profiling can be correlated with the development of anticancer drug resistance. The micro-RNA-mediated form of drug resistance adds yet another mechanism of drug resistance. So, exploiting the emerging knowledge of miRNAs for the development of new human therapeutic applications for overcoming anticancer drug resistance will be important.
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Affiliation(s)
- Tongsen Zheng
- Department of General Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
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477
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Involvement of miR-326 in chemotherapy resistance of breast cancer through modulating expression of multidrug resistance-associated protein 1. Biochem Pharmacol 2009; 79:817-24. [PMID: 19883630 DOI: 10.1016/j.bcp.2009.10.017] [Citation(s) in RCA: 259] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Revised: 10/20/2009] [Accepted: 10/21/2009] [Indexed: 12/19/2022]
Abstract
Multidrug resistance-associated protein (MRP-1/ABCC1) transports a wide range of therapeutic agents and may play a critical role in the development of multidrug resistance (MDR) in tumor cells. However, the regulation of MRP-1 remains controversial. To explore whether miRNAs are involved in the regulation of MRP-1 expression and modulate the sensitivity of tumor cells to chemotherapeutic agents, we analyzed miRNA expression levels in VP-16-resistant MDR cell line, MCF-7/VP, in comparison with its parent cell line, MCF-7, using a miRNA microarray. MCF-7/VP overexpressed MRP-1 mRNA and protein not MDR-1 and BCRP. miR-326 was downregulated in MCF-7/VP compared to MCF-7. Additionally, miR-326 was downregulated in a panel of advanced breast cancer tissues and consistent reversely with expression levels of MRP-1. Furthermore, the elevated levels of miR-326 in the mimics-transfected VP-16-resistant cell line, MCF-7/VP, downregulated MRP-1 expression and sensitized these cells to VP-16 and doxorubicin. These findings demonstrate for the first time the involvement of miRNAs in multidrug resistance mediated by MRP-1 and suggest that miR-326 may be an efficient agent for preventing and reversing MDR in tumor cells.
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478
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miRNAs modulate the drug response of tumor cells. ACTA ACUST UNITED AC 2009; 52:797-801. [DOI: 10.1007/s11427-009-0114-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Accepted: 06/23/2009] [Indexed: 02/06/2023]
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479
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Yu AM. Role of microRNAs in the regulation of drug metabolism and disposition. Expert Opin Drug Metab Toxicol 2009; 5:1513-28. [DOI: 10.1517/17425250903307448] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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480
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Zoon CK, Starker EQ, Wilson AM, Emmert-Buck MR, Libutti SK, Tangrea MA. Current molecular diagnostics of breast cancer and the potential incorporation of microRNA. Expert Rev Mol Diagn 2009; 9:455-67. [PMID: 19580430 DOI: 10.1586/erm.09.25] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Although comprehensive molecular diagnostics and personalized medicine have sparked excitement among researchers and clinicians, they have yet to be fully incorporated into today's standard of care. This is despite the discovery of disease-related oncogenes, tumor-suppressor genes and protein biomarkers, as well as other biological anomalies related to cancer. Each year, new tests are released that could potentially supplement or surpass standard methods of diagnosis, including serum, protein and gene expression analyses. All of these novel approaches have shown great promise, but initial enthusiasm has diminished as difficulties in reproducibility, expense, standardization and proof of significance beyond current protocols have emerged. This review will focus on current and novel molecular diagnostic tools applied to breast cancer with special attention to the exciting new field of microRNA analysis.
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Affiliation(s)
- Christine K Zoon
- Tumor Angiogenesis Section, Surgery Branch National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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481
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Fassan M, Baffa R, Palazzo JP, Lloyd J, Crosariol M, Liu CG, Volinia S, Alder H, Rugge M, Croce CM, Rosenberg A. MicroRNA expression profiling of male breast cancer. Breast Cancer Res 2009; 11:R58. [PMID: 19664288 PMCID: PMC2750120 DOI: 10.1186/bcr2348] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2008] [Revised: 06/15/2009] [Accepted: 08/10/2009] [Indexed: 12/19/2022] Open
Abstract
Introduction MicroRNAs (miRNAs) are a class of small noncoding RNAs that control gene expression by targeting mRNAs and triggering either translation repression or RNA degradation. Their aberrant expression may be involved in human diseases, including cancer. To test the hypothesis that there is a specific miRNA expression signature which characterizes male breast cancers, we performed miRNA microarray analysis in a series of male breast cancers and compared them with cases of male gynecomastia and female breast cancers. Methods Paraffin blocks were obtained at the Department of Pathology of Thomas Jefferson University from 28 male patients including 23 breast cancers and five cases of male gynecomastia, and from 10 female ductal breast carcinomas. The RNA harvested was hybridized to miRNA microarrays (~1,100 miRNA probes, including 326 human and 249 mouse miRNA genes, spotted in duplicate). To further support the microarray data, an immunohistochemical analysis for two specific miRNA gene targets (HOXD10 and VEGF) was performed in a small series of male breast carcinoma and gynecomastia samples. Results We identified a male breast cancer miRNA signature composed of a large portion of underexpressed miRNAs. In particular, 17 miRNAs with increased expression and 26 miRNAs with decreased expression were identified in male breast cancer compared with gynecomastia. Among these miRNAs, some had well-characterized cancer development association and some showed a deregulation in cancer specimens similar to the one previously observed in the published signatures of female breast cancer. Comparing male with female breast cancer miRNA expression signatures, 17 significantly deregulated miRNAs were observed (four overexpressed and 13 underexpressed in male breast cancers). The HOXD10 and VEGF gene immunohistochemical expression significantly follows the corresponding miRNA deregulation. Conclusions Our results suggest that specific miRNAs may be directly involved in male breast cancer development and that they may represent a novel diagnostic tool in the characterization of specific cancer gene targets.
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Affiliation(s)
- Matteo Fassan
- Department of Urology, Thomas Jefferson University - Kimmel Cancer Center, 1112 College Building, 1025 Walnut Street, PA 19107, USA.
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482
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MicroRNAs as New Players for Diagnosis, Prognosis, and Therapeutic Targets in Breast Cancer. JOURNAL OF ONCOLOGY 2009; 2009:305420. [PMID: 19644558 PMCID: PMC2716485 DOI: 10.1155/2009/305420] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Revised: 05/07/2009] [Accepted: 06/03/2009] [Indexed: 02/07/2023]
Abstract
MicroRNAs are small nonprotein-coding RNAs that regulate the expressions of a wide variety of genes by sequence-specific base pairing on the 3′UTR of mRNA targets resulting in mRNA degradation or inhibition of translation. Aberrant expressions of miRNAs have been linked to tumor development, metastasis, diagnosis, prognosis, and therapy response in human breast cancer. Some miRNAs have been considered to have potential clinical applications as a tool for breast cancer prognosis and therapy. Here we describe and discuss lines of evidence supporting the important relationship between miRNAs and breast cancer, and its therapeutic strategies.
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483
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Pan YZ, Gao W, Yu AM. MicroRNAs regulate CYP3A4 expression via direct and indirect targeting. Drug Metab Dispos 2009; 37:2112-7. [PMID: 19581388 DOI: 10.1124/dmd.109.027680] [Citation(s) in RCA: 200] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
CYP3A4 metabolizes many drugs on the market. Although transcriptional regulation of CYP3A4 is known to be tightly controlled by some nuclear receptors (NR) including vitamin D receptor (VDR/NR1I1), posttranscriptional regulation of CYP3A4 remains elusive. In this study, we show that noncoding microRNAs (miRNAs) may control posttranscriptional and transcriptional regulation of CYP3A4 by directly targeting the 3'-untranslated region (3'UTR) of CYP3A4 and indirectly targeting the 3'UTR of VDR, respectively. Luciferase reporter assays showed that CYP3A4 3'UTR-luciferase activity was significantly decreased in human embryonic kidney 293 cells transfected with plasmid that expressed microRNA-27b (miR-27b) or mouse microRNA-298 (mmu-miR-298), whereas the activity was unchanged in cells transfected with plasmid that expressed microRNA-122a or microRNA-328. Disruption of the corresponding miRNA response element (MRE) within CYP3A4 3'UTR led to a 2- to 3-fold increase in luciferase activity. Immunoblot analyses indicated that CYP3A4 protein was down-regulated over 30% by miR-27b and mmu-miR-298 in LS-180 and PANC1 cells. The decrease in CYP3A4 protein expression was associated with significantly decreased CYP3A4 mRNA levels, as determined by quantitative real-time PCR (qPCR) analyses. Likewise, interactions of miR-27b or mmu-miR-298 with VDR 3'UTR were supported by luciferase reporter assays. The mmu-miR-298 MRE site is well conserved within the 3'UTR of mouse, rat, and human VDR. Down-regulation of VDR by the two miRNAs was supported by immunoblot and qPCR analyses. Furthermore, overexpression of miR-27b or mmu-miR-298 in PANC1 cells led to a lower sensitivity to cyclophosphamide. Together, these findings suggest that CYP3A4 gene expression may be regulated by miRNAs at both the transcriptional and posttranscriptional level.
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Affiliation(s)
- Yu-Zhuo Pan
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260-1200, USA
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484
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Shevde LA, Metge BJ, Mitra A, Xi Y, Ju J, King JA, Samant RS. Spheroid-forming subpopulation of breast cancer cells demonstrates vasculogenic mimicry via hsa-miR-299-5p regulated de novo expression of osteopontin. J Cell Mol Med 2009; 14:1693-706. [PMID: 19538464 PMCID: PMC3829031 DOI: 10.1111/j.1582-4934.2009.00821.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The growth of cancer cells as multicellular spheroids has frequently been reported to mimic the in vivo tumour architecture and physiology and has been utilized to study antitumour drugs. In order to determine the distinctive characteristics of the spheroid-derived cells compared to the corresponding monolayer-derived cells, we enriched multicellular spheroid-forming subpopulations of cells from three human breast cancer cell lines (MCF7, MCF10AT and MCF10DCIS.com). These spheroid-derived cells were injected into female athymic nude mice to assess their tumorigenic potential and were profiled for their characteristic miRNA signature. We discovered that the spheroid-derived cells expressed increased levels of osteopontin (OPN), an oncogenic protein that has been clinically correlated with increased tumour burden and adverse prognosis in patients with breast cancer metastasis. Our studies further show that increased OPN levels are brought about in part, by decreased levels of hsa-mir-299–5p in the spheroid-forming population from all three cell lines. Moreover, the spheroid-forming cells can organize into vascular structures in response to nutritional limitation; these structures recapitulate a vascular phenotype by the expression of endothelial markers CD31, Angiopoeitin-1 and Endoglin. In this study, we have validated that hsa-mir-299–5p targets OPN; de novo expression of OPN in turn plays a critical role in enhancing proliferation, tumorigenicity and the ability to display vasculogenic mimicry of the spheroid-forming cells.
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Affiliation(s)
- Lalita A Shevde
- Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA.
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485
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MicroRNA expression and its implications for the diagnosis and therapeutic strategies of breast cancer. Cancer Treat Rev 2009; 35:328-34. [DOI: 10.1016/j.ctrv.2008.12.002] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Revised: 12/16/2008] [Accepted: 12/18/2008] [Indexed: 12/19/2022]
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486
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Kim WC, Lee CH. The role of mammalian ribonucleases (RNases) in cancer. Biochim Biophys Acta Rev Cancer 2009; 1796:99-113. [PMID: 19463900 DOI: 10.1016/j.bbcan.2009.05.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Revised: 05/08/2009] [Accepted: 05/13/2009] [Indexed: 01/01/2023]
Abstract
Ribonucleases (RNases) are a group of enzymes that cleave RNAs at phosphodiester bonds resulting in remarkably diverse biological consequences. This review focuses on mammalian RNases that are capable of, or potentially capable of, cleaving messenger RNA (mRNA) as well as other RNAs in cells and play roles in the development of human cancers. The aims of this review are to provide an overview of the roles of currently known mammalian RNases, and the evidence that associate them as regulators of tumor development. The roles of these RNases as oncoproteins and/or tumor suppressors in influencing cell growth, apoptosis, angiogenesis, and other cellular hallmarks of cancer will be presented and discussed. The RNases under discussion include RNases from the conventional mRNA decay pathways, RNases that are activated under cellular stress, RNases from the miRNA pathway, and RNases with multifunctional activity.
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Affiliation(s)
- Wan-Cheol Kim
- Chemistry Program, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada V2N 4Z9
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487
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Tsuchiya S, Oku M, Imanaka Y, Kunimoto R, Okuno Y, Terasawa K, Sato F, Tsujimoto G, Shimizu K. MicroRNA-338-3p and microRNA-451 contribute to the formation of basolateral polarity in epithelial cells. Nucleic Acids Res 2009; 37:3821-7. [PMID: 19386621 PMCID: PMC2699527 DOI: 10.1093/nar/gkp255] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
MicroRNAs are small noncoding RNA species, some of which are playing important roles in cell differentiation. However, the level of participations of microRNAs in epithelial cell differentiation is largely unknown. Here, utilizing an epithelial differentiation model with T84 cells, we demonstrate that miR-338-3p and miR-451 contribute to the formation of epithelial basolateral polarity by facilitating translocalization of β1 integrin to the basolateral membrane. Among 250 microRNAs screened in this study, the expression levels of four microRNAs (miR-33a, 210, 338-3p and 451) were significantly elevated in the differentiated stage of T84 cells, when epithelial cell polarity was established. To investigate the involvement of these microRNAs in terms of epithelial cell polarity, we executed loss-of- and gain-of-function analyses of these microRNAs. The blockade of endogenous miR-338-3p or miR-451 via each microRNA-specific antisense oligonucleotides inhibited the translocalization of β1 integrin to the basolateral membrane, whereas inhibition of miR-210 or miR-33a had no effect on it. On the other hand, simultaneous transfection of synthetic miR-338-3p and miR-451 accelerated the translocalization of β1 integrin to the basolateral membrane, although the introduction of individual synthetic microRNAs exhibited no effect. Therefore, we concluded that both miR-338-3p and miR-451 are necessary for the development of epithelial cell polarity.
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Affiliation(s)
- Soken Tsuchiya
- Department of Nanobio Drug Discovery, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida Shimoadachi, Sakyo-ku, Kyoto 606-8501, Japan
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488
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Pan YZ, Morris ME, Yu AM. MicroRNA-328 negatively regulates the expression of breast cancer resistance protein (BCRP/ABCG2) in human cancer cells. Mol Pharmacol 2009; 75:1374-9. [PMID: 19270061 DOI: 10.1124/mol.108.054163] [Citation(s) in RCA: 241] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Breast cancer resistance protein (BCRP/ABCG2) is a molecular determinant of pharmacokinetic properties of many drugs in humans. To understand post-transcriptional regulation of ABCG2 and the role of microRNAs (miRNAs) in drug disposition, we found that microRNA-328 (miR-328) might readily target the 3'-untranslated region (3'-UTR) of ABCG2 when considering target-site accessibility. We then noted 1) an inverse relation between the levels of miR-328 and ABCG2 in MCF-7 and MCF-7/MX100 breast cancer cells and 2) that miR-328 levels could be rescued in MCF-7/MX100 cells by transfection with miR-328 plasmid. Luciferase reporter assays showed that ABCG2 3'-UTR-luciferase activity was decreased more than 50% in MCF-7/MX100 cells after transfection with miR-328 plasmid, the activity was increased over 100% in MCF-7 cells transfected with a miR-328 antagomir, and disruption of miR-328 response element within ABCG2 3'-UTR led to a 3-fold increase in luciferase activity. Furthermore, the level of ABCG2 protein was down-regulated when miR-328 was over-expressed, and the level was up-regulated when miR-328 was inhibited by selective antagomir. Altered ABCG2 protein expression was associated with significantly declined or elevated levels of ABCG2 3'-UTR and coding sequence mRNAs, suggesting possible involvement of the mechanism of mRNA cleavage. Finally, miR-328-directed down-regulation of ABCG2 expression in MCF-7/MX100 cells resulted in an increased mitoxantrone sensitivity, as manifested by a significantly lower IC(50) value (2.46 +/- 1.64 microM) compared with the control (151 +/- 32 microM). Together, these findings suggest that miR-328 targets ABCG2 3'-UTR and, consequently, controls ABCG2 protein expression and influences drug disposition in human breast cancer cells.
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Affiliation(s)
- Yu-Zhuo Pan
- Department of Pharmaceutical Sciences, University at Buffalo, The State University of New York, NY 14260-1200, USA
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489
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Suzuki M, Yoshino I. Identification of microRNAs caused by DNA methylation that induce metastasis. Future Oncol 2009; 4:775-7. [PMID: 19086843 DOI: 10.2217/14796694.4.6.775] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Metastasis is a common feature in advanced cancers. To elucidate the mechanism underlying metastasis from analysis of primary disease would have substantial clinical benefit. MicroRNAs (miRNAs) have started a revolution in molecular biology, and emerged as key players in carcinogenesis. They have been identified in various tumor types, showing that different sets of miRNAs are usually deregulated in different cancers. Moreover, some miRNAs are aberrantly methylated and silenced, causing tumorigenesis. In the paper evaluated, the authors identified aberrantly methylated and silenced miRNAs that are cancer-specific using miRNA microarray techniques. Functional analyses for the selected genes proved that these miRNAs act on C-MYC, E2F3, CDK6 and TGIF2, resulting in metastasis through aberrant methylation of the miRNAs. These findings may have broad implications for mechanisms underlying metastasis in malignancies, and may be applicable to advance research in the clinical setting.
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Affiliation(s)
- Makoto Suzuki
- Department of Thoracic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.
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490
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Pharmacoepigenetics: its role in interindividual differences in drug response. Clin Pharmacol Ther 2009; 85:426-30. [PMID: 19242404 DOI: 10.1038/clpt.2009.2] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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491
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Altered microRNA expression patterns in irradiated hematopoietic tissues suggest a sex-specific protective mechanism. Biochem Biophys Res Commun 2008; 377:41-5. [DOI: 10.1016/j.bbrc.2008.09.080] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Accepted: 09/14/2008] [Indexed: 11/23/2022]
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492
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Zhao H, Ardelt B, Ardelt W, Shogen K, Darzynkiewicz Z. The cytotoxic ribonuclease onconase targets RNA interference (siRNA). Cell Cycle 2008; 7:3258-61. [PMID: 18927512 DOI: 10.4161/cc.7.20.6855] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Onconase (Onc), a ribonuclease from oocytes of Northern Leopard frogs (Rana pipiens) is cytostatic and cytotoxic to a variety of tumor lines in vitro, inhibits growth of tumors in animal in vivo models and enhances sensitivity of tumor cells to a number of other cytotoxic agents with diverse mechanism of action. In Phase III clinical trials Onc demonstrated significant efficacy in patients with malignant mesothelioma that failed prior chemotherapy. We previously postulated that the antitumor activity of Onc and the observed synergisms with other antitumor modalities at least in part may be mediated by targeting RNA interference (RNAi). In the present study we observed that the silencing of the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene in human lung adenocarcinoma A549 cells by siRNA was effectively prevented by Onc. While transfection of cells with GAPDH siRNA reduced expression of this protein by nearly 70%, the expression was restored in the cells exposed to 0.8 muM Onc for 48 or 72 h. The data thus provide evidence that one of the targets of Onc is siRNA, likely within the RNA-induced silencing complex (RISC). In light of the findings that microRNAs are involved in tumor pathogenesis as well as in enhancing cell resistance to anticancer therapy the present data may provide explanation for both, the antitumor Onc activity and its propensity to enhance effectiveness of cytotoxic drugs.
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Affiliation(s)
- Hong Zhao
- Department of Pathology, Brander Cancer Research Institute, New York Medical College, Valhalla, New York 10595, USA
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