Transcription profiling of human proliferating oral keratinocytes isolated from normal gingival tissue infected with retorviruses expressing E6 and E6(delta)118-122
ABSTRACT: The goal of this study is to identify genes that are differentially expressed by E6 in oral epithelial cells that are stably expressing Bmi-1. Experiment Overall Design: Primary Normal human oral keratinocytes (NHOK) is explanted from normal human gingival tissue. The cells were infected with retroviruses capable of expressing Bmi-1 and being selected. Actively dividing HOK/Bm-1 cells were then superinfected with LXSN-based retorviruses capable of expressing E6 and E6(delta)118-122, and selected. Actively proliferating cells are then harvested to isolate total RNA which was subsequently subjected to microarray analysis.
Project description:The life cycle of human papillomaviruses (HPV) is strictly linked to the differentiation of their natural host cells. The HPV E6 and E7 oncoproteins can delay the normal differentiation program of keratinocytes, however, the exact mechanisms responsible for this have not yet been identified. The goal of this study was to investigate the effects of HPV16 oncoproteins on the expression of genes involved in keratinocyte differentiation. Primary human keratinocytes transduced by LXSN (control) retroviruses or virus vectors expressing HPV16 E6, E7 or E6/E7 genes were subjected to gene expression profiling. The results of microarray analysis showed that HPV 16 E6 and E7 have the capacity to down-regulate the expression of several genes involved in keratinocyte differentiation. Quantitative real-time polymerase chain reaction (qRT-PCR) assays were performed to confirm microarray data. To investigate the effects of the HPV oncoproteins on the promoters of selected keratinocyte differentiation genes, luciferase reporter assays were performed. Our results suggest that the HPV 16 E6 and/or E7 oncogenes are able to down-regulate the expression of several genes involved in keratinocyte differentiation, at least partially by down-regulating their promoter activity. This activity of the HPV oncoproteins may have a role in the productive virus life cycle, and also in virus induced carcinogenesis. Primary human foreskin keratinocytes were transduced by retrovirus vectors containing HPV 16 E6, E7, E6/E7 or the control vector LXSN. The global gene expression patterns of transduced keratinocytes were analyzed on Affymetrix microarrays
Project description:Cervical cancer is a leading cause of cancer-related death in women worldwide. Nearly all cases of cervical cancer are attributed to infection with human papillomavirus (HPV), mainly high-risk type HPV16 and HPV18. Two viral genes, E6 and E7, play an important role in viral life cycle, since they delay keratinocyte differentiation and stimulate cell cycle progression, allowing the virus to exploit host DNA replication machinery to replicate its genome. Some of the oncogenic properties of E6 and E7 are mediated by host microRNAs (miRNAs) involved in the control of cell proliferation, senescence, and apoptosis. In order to identify genome-wide changes in miRNA expression profile, miRNA microarray analysis was performed on HFKs transduced with retroviral vectors carrying E6 and E7 genes of either HPV6 or HPV16 and with the LXSN empty vector. This dataset was used to identify and to further investigate the role of miR-146a-5p in cervical cancer.
Project description:The E6 and E7 proteins are the major oncogenic drivers encoded by high-risk human papillomaviruses (HPVs). While many aspects of the transforming activities of these proteins have been extensively studied, there are fewer studies that have investigated how HPV E6/E7 expression affects expression of cellular noncoding RNAs. The goal of our study was to investigate HPV16 E6/E7 modulation of cellular microRNA (miR) levels and to determine the potential consequences on cellular gene expression. We performed deep sequencing of small and large cellular RNAs in primary, undifferentiated cultures of human foreskin keratinocytes (HFKs) with stable expression of HPV16 E6/E7 or a control vector. After integration of the two data sets we identified 51 differentially expressed cellular miRs associated with modulation of 1,456 potential target mRNAs in HPV16 E6/E7 expressing HFKs. We discovered that the degree of differential miR expression in HFKs expressing HPV16 E6/E7 was not necessarily predictive of the number of corresponding mRNA targets or the potential impact on gene expression. Additional analyses of the identified miR-mRNA pairs suggest modulation of specific biological activities and biochemical pathways. Overall, our study supports the model that perturbation of cellular miR expression by HPV16 E6/E7 importantly contributes to the rewiring of cellular regulatory circuits by the high-risk HPV E6 and E7 proteins that contribute to oncogenic transformation. Overall design: A total of 8 samples were analyzed, including two replicates of donor and passage matched human foreskin keratinocyte populations transduced with a control LXSN vector, a vector expressing HPV16 E6 alone, HPV16 E7 alone or both HPV16E6 and E7. Large and smal RNA was harvested from each of these samples. RNAseq was performed using large RNA from two populations expressing a control vector and two populations expressing HPV16 E6 and E7 together only (a total of 4 samples). All 8 samples were subjected to small RNAseq (miRNAseq).
Project description:Identification of genetic/cytogenetic alterations and differentially expressed cellular genes in HPV16 E6, E7 and E6/E7 positive human foreskin keratinocytes Keywords: ordered We used microarrays to identify differentially expressed genes in human foreskin keratinocytes (HFK) transfected with retroviral vectors harboring the human papillomavirus type 16 oncogenes E6, E7, or E6/E7 in comparison to HFK containing the empty vector control pLXSN.
Project description:Identification of genetic/cytogenetic alterations and differentially expressed cellular genes in HPV16 E6, E7 and E6/E7 positive human foreskin keratinocytes Keywords: ordered Overall design: We used microarrays to identify differentially expressed genes in human foreskin keratinocytes (HFK) transfected with retroviral vectors harboring the human papillomavirus type 16 oncogenes E6, E7, or E6/E7 in comparison to HFK containing the empty vector control pLXSN.
Project description:HPV E6 from the genus alpha 'high risk' types such as HPV16 recruit the ubiquitin ligase E6AP to ubiquitinate p53 and target it for proteasome-mediated degradation. This results in the functional inactivation of p53 in HPV16-E6 expressing cells. To test what patterns in gene expression might change as a result of HPV16 E6 protein functions and to test whether HPV E6 proteins from genus beta virus types also inactivate p53, we profiled gene expression using Affymetrix arrays before and after stimulating p53 activity via DNA damage in a panel of N/Tert-E6 cell lines. N/Tert-1 human keratinocyte cell lines were cultured in K-SFM (Invitrogen) and treated with 2 ug/ml mitomycin C or with vehicle control for 18 hours. RNA isolated from frozen cell pellets was analyzed on Affymetrix arrays. Each cell line was grown and processed on arrays in 3-5 separate experiments.
Project description:Deregulation of the ubiquitin ligase E6AP is causally linked to the development of human disease, including cervical cancer. In complex with the E6 oncoprotein of human papillomaviruses, E6AP targets the tumor suppressor p53 for degradation, thereby contributing to carcinogenesis. Moreover, E6 acts as a potent activator of E6AP by a yet unknown mechanism. However, structural information explaining how the E6AP-E6-p53 enzyme-substrate complex is assembled, and how E6 stimulates E6AP, is largely missing. We therefore developed and applied different approaches in structural mass spectrometry to show that binding of E6 induces conformational rearrangements in E6AP, which result in the positioning of E6 and p53 in the immediate vicinity of the catalytic centre of E6AP. Our data provides structural and functional insights into the dynamics of the full-length E6AP-E6-p53 enzyme-substrate complex and reveals how E6 can both stimulate the ubiquitin ligase activity of E6AP and facilitate the transfer of ubiquitin from E6AP onto p53.