Project description:Although gain of chromosome-5p is one of the most frequent DNA copy number imbalances in cervical squamous cell carcinoma (SCC), the genes that drive its selection remain poorly understood. In a previous cross-sectional clinical study we showed that the microRNA processor Drosha (located on chromosome-5p) demonstrates frequent copy-number gain and over-expression in cervical SCC, associated with altered microRNA profiles. Here, we have conducted gene depletion/over-expression experiments to demonstrate the functional significance of up-regulated Drosha in cervical SCC cells. Drosha depletion by RNA-interference (RNAi) produced significant, specific reductions in cell motility/invasiveness in vitro, with a silent RNAi-resistant Drosha mutation providing phenotype rescue. Unsupervised hierarchical clustering following global profiling of 319 microRNAs in eighteen cervical SCC cell line specimens generated two groups according to Drosha expression levels. Altering Drosha levels in individual SCC lines changed the group into which the cells clustered, with gene depletion effects being rescued by the RNAi-resistant mutation. Forty-five microRNAs showed significant differential expression between the groups, including four of fourteen that were differentially-expressed in association with Drosha levels in clinical samples. miR-31 up-regulation in Drosha over-expressing samples/cell lines was the highest-ranked change (by adjusted p-value) in both analyses, an observation validated by Northern blotting. These functional data support the role of Drosha as an oncogene in cervical SCC, by affecting expression of cancer-associated microRNAs that have the potential to regulate numerous protein-coding genes. This SuperSeries is composed of the following subset Series: GSE26175: Functional evidence that Drosha over-expression in cervical squamous cell carcinoma affects cell phenotype and microRNA profiles [miRNA] GSE26176: Functional evidence that Drosha over-expression in cervical squamous cell carcinoma affects cell phenotype and microRNA profiles [mRNA] Refer to individual Series
Project description:Although gain of chromosome-5p is one of the most frequent DNA copy number imbalances in cervical squamous cell carcinoma (SCC), the genes that drive its selection remain poorly understood. In a previous cross-sectional clinical study we showed that the microRNA processor Drosha (located on chromosome-5p) demonstrates frequent copy-number gain and over-expression in cervical SCC, associated with altered microRNA profiles. Here, we have conducted gene depletion/over-expression experiments to demonstrate the functional significance of up-regulated Drosha in cervical SCC cells. Drosha depletion by RNA-interference (RNAi) produced significant, specific reductions in cell motility/invasiveness in vitro, with a silent RNAi-resistant Drosha mutation providing phenotype rescue. Unsupervised hierarchical clustering following global profiling of 319 microRNAs in eighteen cervical SCC cell line specimens generated two groups according to Drosha expression levels. Altering Drosha levels in individual SCC lines changed the group into which the cells clustered, with gene depletion effects being rescued by the RNAi-resistant mutation. Forty-five microRNAs showed significant differential expression between the groups, including four of fourteen that were differentially-expressed in association with Drosha levels in clinical samples. miR-31 up-regulation in Drosha over-expressing samples/cell lines was the highest-ranked change (by adjusted p-value) in both analyses, an observation validated by Northern blotting. These functional data support the role of Drosha as an oncogene in cervical SCC, by affecting expression of cancer-associated microRNAs that have the potential to regulate numerous protein-coding genes. This SuperSeries is composed of the SubSeries listed below.
Project description:Comparison of miRNA expression profiles in cervical carcinoma cell lines to study the effects of Drosha expression levels Analyzed global miRNA expression profiles from 18 samples (7 samples in duplicate, 4 single sample) representing cervical carcinoma cell lines with either relative Drosha over-expression (Cluster 2) or Drosha under-expression (Cluster 1), due to wild-type expression in those cell lines or manipulation with RNAi.
Project description:Maturation of canonical microRNA (miRNA) is initiated by DROSHA that cleaves the primary transcript (pri-miRNA). Over 1,800 miRNA loci are annotated in humans, but it remains largely unknown if and at which sites the pri-miRNAs are cleaved by DROSHA. Here we performed in vitro processing on a full set of human pri-miRNAs (miRBase v21) followed by sequencing. This comprehensive profiling enabled us to classify miRNAs based on DROSHA-dependence and map their cleavage sites with respective processing efficiency measures. Only 758 pri-miRNAs are confidently processed by DROSHA, while the majority may be non-canonical or false entries. Analyses of the DROSHA-dependent pri-miRNAs show key cis-elements for processing. We observe widespread alternative processing as well as unproductive cleavage events such as “nick” or “inverse” processing. SRSF3 is a broad-acting auxiliary factor modulating alternative processing and suppressing unproductive processing. The profiling data and methods developed in this study will allow systematic analyses of miRNA regulation.
Project description:MicroRNA 21 (miR-21) has been implicated in various aspects of carcinogenesis. However, the function and molecular mechanism of miR-21 in cervical squamous carcinoma has not been studied. Using TaqMan quantitative real-time PCR and Northern blot, we confirmed that miR-21 is significantly overexpressed in human cervical squamous cancer tissues and cell lines. Remarkably, we showed that the level of miR-21 correlates with the nodal status and differentiation by ISH. Furthermore, we demonstrated that miR-21 regulates cervical squamous cells proliferation, apoptosis, and migration which are HPV16 positive. In order to identify the candidate target genes for miR-21, we used gene expression profiling. By luciferase reporter assay, we confirmed the CCL20 gene is one of its targets, which is relative to the HPV16 oncogenes E6 and E7. Our results suggest that miR-21 may be involved in the cervical squamous cell tumorigenesis.
Project description:Little is known about the alterations in microRNA (miRNA) expression patterns during the consecutive stages of cervical cancer development and their association with chromosomal instability and epigenetic changes. We integrated miRNA expression profiles in normal cervical squamous epithelium, high-grade precancerous lesions (CIN2-3), squamous cell carcinomas (SCC) and adenocarcinomas (AdCAs) with previously generated chromosomal profiles of the same samples. In addition, the DNA methylation status of downregulated miRNAs located in a CpG island was determined. Significantly differential expression during the consecutive stages of cervical SCC development was observed for 106 miRNAs. Altered expression of 5 significantly differentially expressed miRNAs, hsa-miR-9 (1q23.2), hsa-miR-15b (3q25.32), hsa-miR-28-5p (3q27.3), hsa-miR-100 and hsa-miR-125b (both 11q24.1) was directly linked to frequent chromosomal alterations. Another 9 significantly downregulated miRNAs were located within a CpG island. Three of these 9 miRNAs, hsa-miR-203, hsa-miR-572, and hsa-miR-638, showed increased methylation in cervical cancer cell lines and HPV-immortalised cells compared to primary keratinocytes. Functional analyses were performed for hsa-miR-9, representing a potential oncogene with increased expression linked to a chromosomal gain, and hsa-miR-203, representing a potential tumour suppressor gene silenced by DNA methylation. Hsa-miR-9 and hsa-miR-203 were found to alter cell viability and anchorage independent growth in vitro, respectively, supporting their oncogenic and tumour suppressive function in cervical cancer. In conclusion, differential expression of 106 miRNAs, partly associated with chromosomal alterations and epigenetic changes, was observed during cervical SCC development. Altered expression of hsa-miR-9 and hsa-miR-203 was shown to be functionally relevant, underlining the importance of deregulated miRNA expression in cervical carcinogenesis. 10 squamous cell carcinomas of the cervix, 9 adenocarcinomas of the cervix, 18 high-grade cervical intraepithelial neoplasias (CIN2-3), and 10 cervical squamous epithelial samples with normal histology were analysed using single channel (Cy3) miRNA microarrays from Agilent (G4471A-016436).
Project description:We investigated how suppression of the most upstream microRNA–processing RNase, Drosha, affects the differentiation of human CD34+ hematopoietic stem–progenitor cells (HSPCs). We hypothesized that knock-down of Drosha would alter blood lineage development by modulating the expression of microRNAs. Lentiviral delivery to HSPCs of a short-hairpin targeting Drosha resulted in a viable phenotype with promotion of myeloid, and especially monocytic, maturation and suppression of apoptosis. Our results show that Drosha deficiency triggered a parallel upregulation of components of the RNAi machinery, including DGCR8, Dicer and Ago2. Deep sequencing analyses revealed global miRNA deficiency after Drosha short-hairpin treatment with relative maintenance of mature miR-223 expression. Restoration of miR-223 to normal levels after Drosha knock-down further enhanced monocytic maturation concomitant with the modulation of myeloid transcription factors that promoted monocytic differentiation. Our results support a miRNA accentuation model in which relative enhancement of miR-223 increases levels of PU.1 thereby promoting monocytic differentiation.