Dataset Information

Up-regulated Dicer expression in patients with cutaneous melanoma.

ABSTRACT: BACKGROUND: MicroRNAs (miRNAs) are small non-coding RNAs (18-24 nucleotides) that have recently been shown to regulate gene expression during cancer progression. Dicer, a central enzyme in the multi-component miRNA biogenesis pathway, is involved in cutting precursor miRNAs to functionally mature forms. Emerging evidence shows that Dicer expression is deregulated in some human malignancies and it correlates with tumor progression, yet this role has not yet been investigated in skin cancers. METHODS AND FINDINGS: Using an anti-human monoclonal antibody against Dicer and immunohistochemistry, we compared the expression of Dicer protein among 404 clinically annotated controls and skin tumors consisting of melanocytic nevi (n?=?71), a variety of melanomas (n?=?223), carcinomas (n?=?73) and sarcomas (n?=?12). Results showed a cell-specific up-regulated Dicer in 81% of cutaneous, 80% of acrolentiginous and 96% of metastatic melanoma specimens compared to carcinoma or sarcoma specimens (P<0.0001). The expression of Dicer was significantly higher in melanomas compared to benign melanocytic nevi (P<0.0001). In patients with cutaneous melanomas, Dicer up-regulation was found to be significantly associated with an increased tumor mitotic index (P?=?0.04), Breslow's depth of invasion (P?=?0.03), nodal metastasis (P?=?0.04) and a higher American Joint Committee on Caner (AJCC) clinical stage (P?=?0.009). Using western blot analysis, we confirmed the cell-specific up-regulation of Dicer protein in vitro. A pooled-analysis on mRNA profiling in cutaneous tumors showed up-regulation of Dicer at the RNA level in cutaneous melanoma, also showing deregulation of other enzymes that participate in the biogenesis and maturation of canonical miRNAs. CONCLUSIONS: Increased Dicer expression may be a clinically useful biomarker for patients with cutaneous melanoma. Understanding deregulation of Dicer and its influence on miRNA maturation is needed to predict the susceptibility of melanoma patients to miRNA-based therapy in the future.

SUBMITTER: Ma Z

PROVIDER: S-EPMC3117784 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature

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Up-regulated Dicer expression in patients with cutaneous melanoma.

Ma Zhihai Z Swede Helen H Cassarino David D Fleming Elizabeth E Fire Andrew A Dadras Soheil S SS

PloS one 20110617 6

<h4>Background</h4>MicroRNAs (miRNAs) are small non-coding RNAs (18-24 nucleotides) that have recently been shown to regulate gene expression during cancer progression. Dicer, a central enzyme in the multi-component miRNA biogenesis pathway, is involved in cutting precursor miRNAs to functionally mature forms. Emerging evidence shows that Dicer expression is deregulated in some human malignancies and it correlates with tumor progression, yet this role has not yet been investigated in skin cancer ...[more]

PMID: 21698147

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Project description:Sentinel lymph node, the first node draining the primary tumor, is a key component of tumor microenvironment promoting immune tolerance. In melanoma, sentinel node is one of the most important prognostic factors and the most frequent site of regional metastasis. To unravel the immunomodulatory pathways that are triggered by melanoma cells in the draining node that allow tumor spreading, transcriptional profiles associated to disease progression were analyzed in archival sentinel node biopsies (SNB). Gene expression profiles of melanoma-positive and negative SNB selected to maximize the differences in terms of disease stage and course, revealed subgroups correlating with regional node involvement and disease progression within positive biopsies. Transcriptional profiles revealed that genes showing differential expression between tumor-positive SNB with/without disease progression were mainly related to inflammatory response and that were mostly down regulated in patients with poor prognosis. TNFRSF8 encoding CD30 showing up regulation in SNB from patients with progressing disease displayed higher expression by immunohistochemical staining compared to SNB from non progressing patients. Subpopulations of CD30 positive CD4/CD8 double negative and CD4 Foxp3/PD-1 CD147 positive T cells were identified by flow cytometry analysis in metastatic nodes, suggesting a potential role of regulatory and tolerogenic T cells in melanoma progression. Cutaneous melanoma patients undergoing SNB biopsy in 2001-2004 with available 5–year follow-up clinical data were selected. Data relative to 752 cases was extracted, 80% (n= 603) with a negative SNB and 20% (n=149) with SNB positivity for melanoma metastases. The latter underwent regional lymphadenectomy by CLND and 30% (n=44) resulted positive for melanoma metastases at non-sentinel regional lymph nodes while 70% (n=105) resulted negative. Analysis of follow-up data showed that disease recurrence at 5 yrs occurred in 9% SNB negative patients, 14% of the patients with positive SNB resulting negative at CLND, and in 57% of the patients with positive SNB resulting positive at CLND, consistent to the range of previously reported rates (Santinami M 2009, Balch CM 2009). In order to exploit gene expression profiles to unravel molecular modifications occurring in SNB from patients with progressing disease we selected two groups of cases representing the extremes of the survey, i.e. patients positive at CLND (stage IIIB-C) recurring within 5 years follow-up (SNB-PP), and patients negative at CLND (stage IIIA-B) and non-relapsing at 5 years (SNB-PN). In addition, a group of negative SNB patients without disease recurrence at 5 years was selected and analysed for comparison as tumor negative SNB (SNB-N).

Project description:We previously reported reduced expression of Sox4 in metastatic melanoma and its role in suppression of cell migration and invasion through inhibition of nuclear factor (NF)-κB p50. Sox4 can also bind to the promoter sequence of Dicer, a microRNA (miRNA) biogenesis factor. Interestingly, altered expression of Dicer was also observed in cancers. However, the potential mechanisms that regulate Dicer expression and its potential significance in melanoma progression are unknown. Here, we studied the regulation of Dicer expression by Sox4 and its role in suppression of melanoma invasion. Our data showed that Sox4 positively regulates Dicer expression by binding to its promoter sequences and enhancing its activity. We found that knockdown of Dicer enhances the matrigel invasion of melanoma cells by at least twofold. In addition, we revealed that overexpression of exogenous Dicer reverts the enhanced melanoma cell invasion upon Sox4 knockdown. Furthermore, we examined the expression of Dicer protein in a large set of melanocytic lesions (n=514) at different stages by tissue microarray and found that Dicer expression is inversely correlated with melanoma progression (P<0.0001). Consistently, reduced Dicer expression was correlated with a poorer overall and disease-specific 5-year survival of patients (P=0.015 and 0.0029, respectively). In addition, we found a significant correlation between expression of Sox4 and Dicer proteins in melanoma biopsies (P=0.009), further indicating the regulation of Dicer expression by Sox4. Finally, we revealed that knockdown of Sox4 induces a major change in the expression pattern of miRNAs in melanoma cells, mainly due to reduced expression of Dicer. Our results pinpoint the regulation of Dicer expression by Sox4 in melanoma and the critical role of Dicer in suppression of melanoma invasion. Our findings on Sox4-regulated miRNA biogenesis pathway may aid toward the development of novel targeted therapeutic approaches for melanoma.

Project description:Perturbations in microRNA (miRNA) expression profiles has been reported for cutaneous malignant melanoma (CMM). With regards to a rapidly growing number of newly discovered miRNA sequences, the availability of up-to-date miRNA expression profiles for primary cutaneous malignant melanoma (PCMM), cutaneous malignant melanoma metastases (CMMM) and benign melanocytic naevi (BMN) is limited. Patients with PCMM (n=9), CMMM (n=4) and BMN (n=8) were included in the study. Specimens were obtained during surgery from the center of the tumors (lesional). An exploratory microarray analysis was performed by miRNA expression profiling based on miRBase V.16. Additionally, the expression levels of selected miRNA candidates were confirmed by TaqMan real-time quantitative polymerase chain reaction (RT-PCR). New miRNA candidates previously not described to be associated with CMM were found to be potentially dysregulated in CMM. Nine patients with PCMM (PCMM1-PCMM9), four patients with CMMM (CMMM1-CMMM4) and eight patients with BMN (BMN1-BMN8) were enrolled in the present study. All cutaneous specimens were harvested in the operating room, immediately stored in RNAlater (Quiagen, Hilden, Germany) and kept at - 80 °C until RNA isolation. Total RNA including miRNAs was isolated using the miRNeasy Mini Kit (Quiagen, Hilden, Germany) according to the manufacturer’s protocol. RNA concentration and purity was determined by NanoDrop ND-1000 spectral photometer (Peqlab, Erlangen, Germany). RNA integrity control (RIN) was determined by means of capillary electrophoresis with the 2100 Bioanalyzer and the RNA 6000 NanoLabCHip Kits (both Agilent Technologies, Santa Clara, USA). To be further considered for Microarray analysis a RIN ≥ 7.0 indicating medium to good RNA quality was defined as inclusion criteria. For assessment of labeling and hybridization efficiencies total RNA samples were spiked with in-vitro synthesized oligonucleotides by using the MicroRNA Spike-In Kit (Agilent Technologies, Santa Clara, USA). A total of 100 ng total RNA per sample were introduced into a labeling reaction. The spiked total RNA was treated with alkaline calf intestine phosphatase (CIP). The dephosphorylated RNA was labeled with the miRNA Complete Labeling and Hyb Kit (Agilent Technologies, Santa Clara, USA) according to the manufacturer´s instructions using T4 RNA ligase, incorporating Cyanine 3-Cytidine biphosphate (pCp). The Cyanine-3-labeled miRNA samples were prepared for One-Color based hybridization with Complete miRNA Labeling and Hyb Kit (Agilent Technologies, Santa Clara, USA) according to the manufacturer´s instructions. Labeled miRNA samples were hybridized at 55°C for 20 hrs on separate Human miRNA Microarrays Release 16.0 (8x60K format, (Agilent Technologies, Santa Clara, USA). Afterwards, microarrays were washed with increasing stringency using Gene Expression Wash Buffers (Agilent Technologies, Santa Clara, USA) followed by drying with acetonitrile (Sigma-Aldich, St.Louis, USA). Fluorescent signal intensities were detected with Scan Control A.8.4.1 Software (Agilent Technologies, Santa Clara, USA) on the Agilent DNA Microarray Scanner and extracted from the images using Feature Extraction 10.7.3.1 Software (Agilent Technologies, Santa Clara, USA). All the steps described were carried out according to the manufacturer´s instructions.

Dataset Information

Up-regulated Dicer expression in patients with cutaneous melanoma.

Publications

Up-regulated Dicer expression in patients with cutaneous melanoma.

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