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.
Project description:Human papillomavirus (HPV) genome integration into the host genome, blocking E2 expression and leading to overexpression of E6 and E7 viral oncogenes, is considered a major step in cervical cancer development. In high-risk HPVs, E6 and E7 oncogenes are expressed as a bicistronic pre-mRNA, with alternative splicing producing the ultimate mRNAs required for E6 and E7 translation. Given the number of alternative donor and acceptor splicing sites, ten E6/E7 different alternative transcripts might be formed for HPV16 and three for HPV18, although only six isoforms have been previously reported for HPV16. In the present work, we employ high-throughput sequencing of invasive cervical cancer transcriptome (RNA-Seq) to characterize the expression of the HPV genome in 24 invasive cervical cancers associated with HPV16 and HPV18 single infections. Based on high-resolution transcriptional maps, we herein report three viral gene expression patterns which might be associated with the presence of the viral genome in episomal and/or integrated stages. Alternative mRNAs splicing isoforms coding for E6 and E7 oncoproteins were characterized and quantified, and two novel isoforms were identified. Three major isoforms (E6*I, E6*II, and E6+E7) were detected for HPV16 and two for HPV18 (E6*I and E6+E7). Minor transcript isoforms, including the novel ones, were very rare in some tumor samples or were not detected. Our data suggested that minor transcript isoforms of E6/E7 do not play a relevant role in cervical cancer.
Project description:Human papillomavirus (HPV) is the etiological agent of cervical cancer. Three viral proteins, E5, E6 and E7 have been implicated in cell transformation. Increased expression of sialic acid and sialylated antigens have been reported during cervix transformation, these results agree with the increased mRNA levels of the sialyltransferases genes ST6GAL1 and ST3GAL3 reported in premalignant and malignant tissue of the cervix. E6 and E7 HPV oncoproteins modify the expression of some glycogenes. The role of E5 HPV oncoprotein in the glycogene expression changes in premalignant and malignant cervical tissue has not been reported. The objective of this work was to identify glycogenes that modify their expression by E5 HPV oncoprotein in HaCaT cell line. A gene expression microarray was performed on HaCaT cells that stably expressed the HPV16 E5 oncogene. Analysis revealed alteration in some glycogenes including upregulation of ST6GAL1 and ST3GAL3. The increased mRNA levels of both genes were confirmed by qRT-PCR. In addition, an in-silico analysis was performed to identify glycosylation networks altered in presence of E5 oncoprotein. The analysis showed that E5 could modify the sialic acid expression, keratan sulfate synthesis, N-glycosylation and biosynthesis of glycosaminoglycans. This is the first report of the role of HPV16 E5 oncoprotein on glycogenes expression changes. Moreover, our results suggest that the increase of the sialyltransferases genes reported in premalignant and malignant cervical tissue, could be the result of the expression of E5 oncoprotein. These results provide information of the possible role of HPV infection on the sialylation changes in the cervical epithelium identified in premalignant lesions and cancer.
Project description:The infection with high-risk human papillomavirus is aetiologically linked to cervical cancer, the role of miRNAs regulated by virus oncogene in cancer progression remain largely unknown. Here, we screened the differentially expressed miRNAs with miRNA array between virus oncogene e6/e7 silenced and not in HPV16-positive cervical cancer cell lines In the study, we screened the differentially expressed miRNAs with miRNA array (Exiqon, miRCURY LNA microRNA array, 7th gen [hsa, miRBase 18]) between virus oncogene e6/e7 silenced and not in HPV16-positive cervical cancer cell lines to found miRNAs regulated by virus oncogene e6/e7. Biological replicates: 3 control, 3 e6/e7 silenced, independently grown and harvested. four replicates per array.
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 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: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.
Project description:Comparative analysis of RNA expression profiles of keratinocytes expressing E6/E7 from the different beta-3, with the RNA profiles of HPV16 and HPV38 E6/E7 HFKs reveals that HPV115 is the more divergent from the HR-mucosal type. Moreover beta-3 HPV 49, 75 and 76 E6/E7 HFKs show altered expression of genes involved in cell cycle regulation and DNA damage response which are also deregulated by expression of E6/E7 of HPV16.
Project description:We utilised our in vitro model of cervical neoplastic progression, W12, to investigate the effect of HPV16 viral oncogene depletion on well-defined integrant- and episome- associated series. To target HPV16 viral oncogenes we used our previously published E7-targeting siRNA sequence that caused substantial depletion of both E7 and E6 in CaSki cells. We found all E7-siRNA treated W12 series underwent widespread autophagy and senescence, with up-regulation of an innate immune response.