Detection of HPV and the role of p16INK4A overexpression as a surrogate marker for the presence of functional HPV oncoprotein E7 in colorectal cancer

<p>Abstract</p> <p>Background</p> <p>Based on the well-recognized etiological role of human papillomavirus (HPV) in cervical, anogenital and oropharyngeal carcinogenesis, a potential role of HPV in colorectal carcinogenesis has been suggested. For that reason, the aim of the present study was to investigate the presence of HPV DNA in colorectal carcinomas (CRC) and to study overexpression of p16^INK4Aas a marker for the presence of an active HPV oncoprotein E7. These findings were correlated with clinical and pathological prognostic factors of CRC.</p> <p>Methods</p> <p>The presence of HPV was assessed using a multiplex PCR system of 10 non-biotinylated primers. The amplified fragments of HPV positive samples were further analyzed by a highly sensitive, broad spectrum SPF10 PCR and subsequently genotyped using reverse hybridization in a line probe assay.</p> <p>P16^INK4Aprotein expression was investigated in a subset of 90 (30 HPV positive and 60 HPV negative) CRC samples by immunohistochemistry.</p> <p>Results</p> <p>HPV DNA was found in 14.2% of the CRC samples with HPV16 as the most prevalent type. No significant differences in clinical and pathological variables were found between HPV positive and negative CRCs, except for age. HPV positive patients were significantly younger (p = 0.05). There was no significant correlation between the presence of HPV and overexpression of p16^INK4A(p = 0.325).</p> <p>Conclusions</p> <p>In conclusion, the presence of oncogenic HPV DNA in a small cohort of CRC samples may suggest that HPV may be involved in the carcinogenesis of some CRC. However, contrary to what has been observed in head and neck squamous cell cancer and cancer of the uterine cervix, p16^INK4Adoes not seem to be a surrogate marker for an active HPV infection in CRC. Therefore, further functional analyses are necessary to elucidate the role of HPV in CRC.</p

Prévalence et expression des papillomavirus humains dans les cellules trophoblastiques et cervicales

Human papillomavirus (HPV) is a double-stranded DNA virus, typically infecting mucosal or cutaneous epithelial keratinocytes. Today, more than 118 different HPV types have been formally described. Sexual transmission of mucosal HPVs is very common and generally asymptomatic, but HPV infection can be associated with benign lesions such as condylomata acuminata or, in rare cases, with malignant lesions such as cervical cancer. Two prophylactic vaccines are currently available in Europe, protecting against HPV-16 and HPV-18 (Cervarix&63720;) or against HPV-6, HPV-11, HPV-16 and HPV-18 (Gardasil&63720;). In order to assess the impact of the vaccination program, it is mandatory to obtain geographically widespread date on the baseline HPV prevalence and type distribution in cervical samples from women, presenting or not, normal or abnormal cytologic or histologic results. We undertook an epidemiological study in the Capital Region of Brussels to determine the HPV prevalence and type-distribution in 1526 cervical samples of women presenting a cytology within normal limits (WINL), atypical squamous cells of undetermined significance (ASC-US), low-grade squamous intra-epithelial lesions (LSIL), high-grade squamous intra-epithelial lesions (HSIL) or invasive cervical cancer (ICC). The HPV prevalence was 10.8% (95%CI: 8.8-12.8) for NILM, 34.5% (95%CI: 28.3-40.8) for ASC-US, 54.0% (95%CI: 47.4-60.6) for LSIL and 100% for HSIL and ICC. With an HPV-16 and HPV-18 prevalence of 63.3% (95%CI: 44.1-67.7) and 73.5% (95%CI: 63.0-84.0) in mono-infected HSIL and ICC, respectively, HPV 16/18 L1 VLP vaccines would be expected to significantly reduce the management and treatment of women suffering from HSIL and ICC in the Capital Region of Brussels. We also detected HPV-30, HPV-53, HPV-66 and HPV-68 in mono-infected HSIL and ICC samples, possibly providing arguments for the reconsideration of the carcinogenicity of these types. Vertical transmission of HPV was also previously reported, but in most cases one could not exclude a placental contamination by HPV positive cells from an infected birth canal. In order to confirm that the placenta can be infected with HPV, we analysed residual cells from 35 transabdominally obtained placental samples from pregnant women undergoing chorionic villous sampling for screening of suspected foetal abnormalities and found that two samples were positive for HPV-16 and HPV-62, respectively. The clinical importance of these results remains to be elucidated, but the previously observed association between placental HPV infection and pregnancy loss might gain further in importance. HPV gene regulation in placental trophoblastic cells has not been studied so far. We studied the HPV-16 early gene expression regulation in transiently transfected monolayer cultured trophoblastic cells with an HPV-16 long control region (LCR) driven reporter plasmid. We observed important differences in constitutive HPV-16 LCR activities between trophoblastic cell lines and could identify progesterone as an important inducer of HPV-16 early gene expression. Steroid hormones are induced during pregnancy and could therefore lead to an enhanced expression of the E5, E6 and E7 proteins upon placental HPV infection. Since these proteins were previously shown to affect trophoblast adhesion, survival, migration and invasion, their enhanced expression might eventually contribute to pregnancy loss. We furthermore found that the transcription of episomally maintained HPV-16 is not regulated by E2 or E1, but by E5, E6 and/or E7. Doctorat en Sciences biomédicales et pharmaceutiquesinfo:eu-repo/semantics/nonPublishe

Prévalence et expression des papillomavirus humains dans les cellules trophoblastiques et cervicales

Human papillomavirus (HPV) is a double-stranded DNA virus, typically infecting mucosal or cutaneous epithelial keratinocytes. Today, more than 118 different HPV types have been formally described. Sexual transmission of mucosal HPVs is very common and generally asymptomatic, but HPV infection can be associated with benign lesions such as condylomata acuminata or, in rare cases, with malignant lesions such as cervical cancer. Two prophylactic vaccines are currently available in Europe, protecting against HPV-16 and HPV-18 (Cervarix&63720;) or against HPV-6, HPV-11, HPV-16 and HPV-18 (Gardasil&63720;). In order to assess the impact of the vaccination program, it is mandatory to obtain geographically widespread date on the baseline HPV prevalence and type distribution in cervical samples from women, presenting or not, normal or abnormal cytologic or histologic results. We undertook an epidemiological study in the Capital Region of Brussels to determine the HPV prevalence and type-distribution in 1526 cervical samples of women presenting a cytology within normal limits (WINL), atypical squamous cells of undetermined significance (ASC-US), low-grade squamous intra-epithelial lesions (LSIL), high-grade squamous intra-epithelial lesions (HSIL) or invasive cervical cancer (ICC). The HPV prevalence was 10.8% (95%CI: 8.8-12.8) for NILM, 34.5% (95%CI: 28.3-40.8) for ASC-US, 54.0% (95%CI: 47.4-60.6) for LSIL and 100% for HSIL and ICC. With an HPV-16 and HPV-18 prevalence of 63.3% (95%CI: 44.1-67.7) and 73.5% (95%CI: 63.0-84.0) in mono-infected HSIL and ICC, respectively, HPV 16/18 L1 VLP vaccines would be expected to significantly reduce the management and treatment of women suffering from HSIL and ICC in the Capital Region of Brussels. We also detected HPV-30, HPV-53, HPV-66 and HPV-68 in mono-infected HSIL and ICC samples, possibly providing arguments for the reconsideration of the carcinogenicity of these types. Vertical transmission of HPV was also previously reported, but in most cases one could not exclude a placental contamination by HPV positive cells from an infected birth canal. In order to confirm that the placenta can be infected with HPV, we analysed residual cells from 35 transabdominally obtained placental samples from pregnant women undergoing chorionic villous sampling for screening of suspected foetal abnormalities and found that two samples were positive for HPV-16 and HPV-62, respectively. The clinical importance of these results remains to be elucidated, but the previously observed association between placental HPV infection and pregnancy loss might gain further in importance. HPV gene regulation in placental trophoblastic cells has not been studied so far. We studied the HPV-16 early gene expression regulation in transiently transfected monolayer cultured trophoblastic cells with an HPV-16 long control region (LCR) driven reporter plasmid. We observed important differences in constitutive HPV-16 LCR activities between trophoblastic cell lines and could identify progesterone as an important inducer of HPV-16 early gene expression. Steroid hormones are induced during pregnancy and could therefore lead to an enhanced expression of the E5, E6 and E7 proteins upon placental HPV infection. Since these proteins were previously shown to affect trophoblast adhesion, survival, migration and invasion, their enhanced expression might eventually contribute to pregnancy loss. We furthermore found that the transcription of episomally maintained HPV-16 is not regulated by E2 or E1, but by E5, E6 and/or E7. Doctorat en Sciences biomédicales et pharmaceutiquesinfo:eu-repo/semantics/nonPublishe

Regulation of the transcriptional activity of human papillomavirus type 16 LCR in choriocarcinoma cell lines

info:eu-repo/semantics/publishe

The trophoblast: a model to study HPV transcription, replication and host cell interactions

info:eu-repo/semantics/publishe

The trophoblast: a model to study HPV transcription, replication and host cell interactions

info:eu-repo/semantics/publishe

Extrachromosomal HPV-16 LCR transcriptional activation by HDACi opposed by cellular differentiation and DNA integration

Histone deacetylase inhibitors (HDACi) have been shown to render HPV-carrying cells susceptible to intrinsic and extrinsic apoptotic signals. As such, these epigenetic drugs have entered clinical trials in the effort to treat cervical cancer. Here, we studied the effect of common HDACi, with an emphasis on Trichostatin A (TSA), on the transcriptional activity of the HPV-16 Long Control Region (LCR) in order to better understand the impact of these agents in the context of the HPV life cycle and infection. HDACi strongly induced transcription of the firefly luciferase reporter gene under the control of the HPV-16 LCR in a variety of cell lines. In the HaCaT keratinocyte cell line undergoing differentiation induced by TSA, we observed a reduction in LCR-controlled transcription. Three major AP-1 binding sites in the HPV-16 LCR are involved in the regulation by TSA. However, whatever the status of differentiation of the HaCaT cells, TSA induced integration of extra-chromosomal transfected DNA into the cellular genome. Although these data suggest caution using HDACi in the treatment of HR HPV infection, further in vivo studies are necessary to better assess the risk.SCOPUS: ar.jinfo:eu-repo/semantics/publishe