Human papillomaviruses (HPVs) are involved in the pathogenesis of cancer of the cervix (CaCx). MicroRNA (miRNA) expression analysis using Ambion (Austin, TX, USA) arrays showed that three miRNAs were overexpressed and 24 underexpressed in cervical cell lines containing integrated HPV-16 DNA compared to the normal cervix. Furthermore, nine miRNAs were overexpressed and one underexpressed in integrated HPV-16 cell lines compared to the HPV-negative CaCx cell line C-33A. Based on microarray and/or quantitative realtime PCR and northern blot analyses, microRNA-218 (miR-218) was specifically underexpressed in HPVpositive cell lines, cervical lesions and cancer tissues containing HPV-16 DNA compared to both C-33A and the normal cervix. Expression of the E6 oncogene of highrisk HPV-16, but not that of low-risk HPV-6, reduced miR-218 expression, and conversely, RNA interference of E6/E7 oncogenes in an HPV-16-positive cell line increased miR-218 expression. We also demonstrate that the epithelial cell-specific marker LAMB3 is a target of miR-218. We also show that LAMB3 expression is increased in the presence of the HPV-16 E6 oncogene and this effect is mediated through miR-218. These findings may contribute to a better understanding of the molecular mechanisms involved in cervical carcinogenesis.

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Human papillomaviruses (HPVs) have been implicated in the pathogenesis of a subset of squamous cell carcinoma of the head and neck (SCCHN). The goal of this study was to compare the cellular gene expression profiles of HPV-positive and HPV-negative oropharyngeal carcinomas with those of the normal oral epithelium. Using Affymetrix Human U133A GeneChip, our results showed that 397 genes were differentially expressed in HPV-positive SCCHN compared to the normal oral epithelium. The up-regulated genes included those involved in cell cycle regulation (CDKN2A), cell differentiation (SFRP4) and DNA repair (RAD51AP1), while the down-regulated genes included those involved in proteolysis (PRSS3). We also found 162 differentially expressed genes in HPVnegative SCCHN compared to the normal oral mucosa. The up-regulated genes included those involved in cell proliferation (AKR1C3) and transcription regulation (SNAPC1), while downregulated genes included those involved in apoptosis (CLU) and RNA processing (RBM3). Our studies also identified a subgroup of 59 differentially expressed genes in HPV-positive SCCHN as compared to both HPV-negative SCCHN and normal oral tissues. Such up-regulated genes included those involved in nuclear structure and meiosis (SYCP2), DNA repair (RFC5), and transcription regulation (ZNF238). Genes involved in proteolysis (KLK8) and signal transduction (CRABP2) were found to be down-regulated in HPV-positive SCCHN. The results of GeneChip experiments were validated by quantitative real-time RT-PCR analysis of a few representative genes. Our results reveal specific gene expression patterns in HPV-positive and HPV-negative oropharyngeal squamous carcinomas that may serve as potential biomarkers for the development of SCCHN. Novelty and impact of the paper: Using a 22,200 human transcript oligonucleotide microarray platform, we have examined the gene expression profiles in HPV-positive and HPV-negative oropharyngeal squamous cell carcinomas as compared to the normal oropharyngeal mucosa. Our study has identified several new genes whose expression is specifically associated with the presence of HPV-16 in the oropharyngeal squamous mucosa. Furthermore, we have identified several genes whose expression is altered in HPVnegative SCCHN as compared to the normal oral mucosa. Results of our study could contribute to the understanding of pathogenic mechanisms involved in the development of HPV-positive and HPV-negative oropharyngeal cancers and consequently in the identification of potential biomarkers associated with these two subtypes of squamous cell carcinomas.

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