RNA profiling of cervical cancer exosomes using next- generation sequencing.
Ontology highlight
ABSTRACT: In the preset study we isolated and characterized exosomes from both HPV positive and negative cervical cancer cell lines and identified a subset of mRNA’s enriched specifically in HPV positive exosomes through deep sequencing methods. Potential target prediction gene ontology, KEGG pathway analysis revealed possible functions associated with differentially expressed genes of CaCx exosomes. Profiling of these exosomes also revealed the export of HPV 16 associated transcripts (E1,E2, E5, and L2) within SiHa exosomes, however no such export was observed for major oncogenic transcripts (E6 and E7). Our Reverse transcription PCR experiments could validate our deep sequencing results for the absence of E6, E7 transcripts in exosomes. Interestingly, PCR could amplify a truncated version of E6 transcript in HeLa exosomes, which was not detectable in our sequencing results.
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:Human papillomavirus (HPV) E6 and E7 oncoproteins are expressed at all stages of HPV-mediated carcinogenesis and are essential drivers of cancers caused by high-risk HPV. Some of the activities of HPV E6 and E7, such as their interactions with host cellular tumor suppressors, have been characterized extensively. There is less information about how high-risk HPV E6 and E7 alter cellular responses to cytokines that are present in HPV-infected tissues and are an important component of the tumor microenvironment. We used several models of HPV oncoprotein activity to assess how E6 and E7 alter the cellular response to the pro-inflammatory cytokine IL-1beta. Models of early-stage HPV infection (human keratinocytes expressing HPV16 E6 and E7) and models of established HPV-positive head and neck cancers (patient-derived xenografts, head and neck cancer cell lines) exhibited similar dysregulation of IL-1 pathway genes and suppressed responses to IL-1beta treatment. Such overlap in cell responses supports that changes induced by HPV E6 and E7 early in infection could persist and contribute to a dysregulated immune environment throughout carcinogenesis. HPV E6 and E7 also drove the upregulation of several suppressors of IL-1 cytokine signaling, including SIGIRR, both in primary keratinocytes and in cancer cells. SIGIRR knockout was insufficient to increase IL-1beta-dependent gene expression in the presence of HPV16 E6 and E7, suggesting that multiple suppressors of IL-1 signaling contribute to dampened IL-1 responses in HPV16-positive cells.
Project description:Many DNA tumor viruses inhibit or repurpose host DNA repair pathways to evade viral defense mechanisms or promote their own replication. High risk genus α human papillomaviruses (α-HPVs) express two versatile oncogenes (α-HPV E6 and E7) that use both approaches simultaneously. To identify new interactions with DNA repair pathways, we conducted a computational analysis of gene expression in cervical cancer (CaCx) transcriptomic datasets and identified a frequent upregulation of translesion synthesis (TLS) genes. TLS polymerase genes, particularly the gene for POLη (POLH), did not follow this pattern. Characterization of α-HPV oncogene expressing cell lines and premalignant cervical tissue confirm these data. They also show that the increased TLS protein abundance come in response to nucleoside depletion. Primary and transformed cell lines to demonstrate that α-HPV E6 blocks POLη induction by degrading p53. Lack of POLη dooms the pathway, preventing it from facilitating tolerance of replication stress. Failed TLS results in replication fork stalling and collapse into deleterious double strand breaks in the DNA (DSBs). Consequently, cellular genome fidelity decreases in a manner consistent with the mutations that accumulate during CaCx progression. Alterations in TLS are determinants for the efficacy of the chemotherapeutics most often used to treat CaCx (cisplatin and carboplatin). Exogenous expression of POLη protected CaCx cells from cisplatin-associated toxicity/damage, effectively stabilizing their genome. TLS polymerase expression is also a prognostic factor in CaCx. Analysis of the cancer genome atlas database (TCGA) shows increased expression of these genes correlated with over a decade shorter median survival.
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 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:The high-risk subgroup of Human papilloma viruses (HPVs), exemplified by HPV16/18, are causally linked to human cancers of the anogenital tract, skin, and upper aerodigestive tract. The high-risk HPV oncoproteins E6 and E7 are expressed from a polycistronic transcript that can potentially give rise to alternatively spliced E6 mRNAs, a process important for E6 and E7 expression and oncogenic transformation. Previously, we identified ECD, the human homologue of the Drosophila ecdysoneless gene, as a novel HPV16 E6-interacting protein using Yeast two-hybrid system. Here, we show that the C-terminal region of ECD selectively binds to high-risk but not to low-risk HPV E6 proteins. We demonstrate that ECD is overexpressed in HPV+ as well as HPV- cervical and head and neck patient tumor samples. Using the TCGA dataset, we show that ECD mRNA overexpression predicts shorter survival in these cancer patients. Recent work from our laboratory showed that ECD associates with several components of RNA biogenesis/splicing machinery and are involved in mRNA export. Here, we show that ECD is an RNA binding protein and regulates mRNA splicing. RNAseq analyses of SiHa cells upon ECD knockdown (KD) revealed alterations of many cellular pathways with prominent downregulation of components of the mRNA splicing machinery. Further investigation revealed that ECD KD resulted in dysregulation of E6 RNA splicing, resulting in decreased E7 and increased RB protein. Furthermore, ECD KD dysregulated several cellular mRNAs known to be critical for HPV oncogenesis. Finally, we demonstrate that while ECD KD in cervical cancer cell lines led to a reduction in oncogenic traits, ECD overexpression together with E7 led to the immortalization of keratinocytes. Taken together, our results support a novel role of ECD in transcription and in viral and cellular mRNA splicing to support HPV-driven oncogenesis.
Project description:The human papillomavirus virus (HPV) is a proven cause of most human cervical cancers, and might have a role in other malignancies including vulva, skin, oesophagus, head and neck cancer. HPV has also been speculated to have a role in the pathogenesis of lung cancer. To validate the hypothesis of HPV involvement in small cell lung cancer pathogenesis we performed gene expression profile of transgenic mouse model of SCLC induced by HPV-16 E6/E7 oncoproteins. Gene expression profile of SCLC has been performed using Agilent whole mouse genome (4x44k) representing ~ 41000 genes and mouse transcripts. Samples were obtained from two HPV16-E6/E7 transgenic mouse model and from littermateM-bM-^@M-^Ys normal lung.
Project description:Gene methylation profiling of immortalized human mesenchymal stem cells comparing HPV E6/E7-transfected MSCs cells with human telomerase reverse transcriptase (hTERT)- and HPV E6/E7-transfected MSCs. hTERT may increase gene methylation in MSCs. Goal was to determine the effects of different transfected genes on global gene methylation in MSCs.
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.