Showing papers by "Massimo Tommasino published in 2007"
TL;DR: A novel mechanism used by HPV16 to suppress the host immune response by deregulating the TLR9 transcript is revealed, providing evidence that abolishing innate responses may be a crucial step involved in the carcinogenic events mediated by HPVs.
Abstract: Cervical cancer development is linked to the persistent infection by high-risk mucosal human papillomaviruses (HPVs) types. The E6 and E7 major oncoproteins from this dsDNA virus play a key role in the deregulation of the cell cycle, apoptosis, and adaptive immune surveillance. In this study, we show for the first time that HPV type 16 (HPV16), the most carcinogenic type among the high-risk subgroup, interferes with innate immunity by affecting the expression of TLRs. Infection of human primary keratinocytes with HPV16 E6 and E7 recombinant retroviruses inhibits TLR9 transcription and hence functional loss of TLR9-regulated pathways. Similar findings were achieved in HPV16-positive cancer-derived cell lines and primary cervical cancers, demonstrating that this event occurs also in an in vivo context. Interestingly, E6 and E7 from the low-risk HPV type 6 are unable to down-regulate the TLR9 promoter. In addition, E6 and E7 from the high-risk HPV type 18, which are known to persist less competently in the host than HPV16, have reduced efficiency compared with HPV16 in inhibiting TLR9 transcription. Furthermore, a CpG motif derived from the HPV16 E6 DNA sequence activated TLR9, indicating this virus is able to initiate innate responses via the receptor it later down-regulates. This study reveals a novel mechanism used by HPV16 to suppress the host immune response by deregulating the TLR9 transcript, providing evidence that abolishing innate responses may be a crucial step involved in the carcinogenic events mediated by HPVs.
333 citations
TL;DR: A novel one-shot method for the detection of all characterized beta HPV types, namely, HPV type 5 (HPV5), 8, 9, 12, 14, 15, 17, 19, 20, 21, 22, 23, 24, 25, 36, 37, 38, 47, 49, 75, 76, 80, 92, 93, and 96.
Abstract: Emerging lines of evidence indicate that the cutaneous human papillomavirus (HPV) types that belong to the genus Betapapillomavirus (beta HPV) are involved in the development of nonmelanoma skin cancer. Unlike the situation for mucosal HPV types, highly sensitive and reliable methods to identify characterized cutaneous HPV types in a single assay are limited. Here, we describe a novel one-shot method for the detection of all characterized beta HPV types, namely, HPV type 5 (HPV5), 8, 9, 12, 14, 15, 17, 19, 20, 21, 22, 23, 24, 25, 36, 37, 38, 47, 49, 75, 76, 80, 92, 93, and 96. This assay combines two different techniques: multiplex PCR using HPV type-specific primers for amplification of each E7 gene and array primer extension (APEX) for typing. This method has been validated using clinical samples which were analyzed simultaneously for the presence of cutaneous HPV types by two additional methods, i.e., the FAP59/64 PCR protocol and a commercially available PCR-reverse hybridization assay (PM-PCR RHA). Our data show good agreement between the results obtained with the multiplex PCR/APEX assay and the PM-PCR RHA method (overall HPV positivity of 92.2% for multiplex PCR/APEX assay versus 90.6% with the PM-PCR RHA) (kappa value, 50; 95% confidence interval, 13 to 88). In addition, the multiplex PCR/APEX assay showed higher sensitivity than the PM-PCR RHA did. This favorable feature and the high-throughput potential make this assay ideal for large-scale clinical and epidemiological studies aimed at determining the spectrum of cutaneous types in skin cancer.
93 citations
TL;DR: It is shown that TLR3 and TLR4 can induce cell cycle entry via TRIF, which targets the cell cycle inhibitor p27kip1 for relocalization, phosphorylation by cyclin/cdk complexes, and proteasome degradation, and these events are antagonized by type I IFN induced by the TRIF pathway.
Abstract: TRIF is an adaptor protein associated with the signaling by Toll-like receptor (TLR)3 and TLR4 for the induction of type I IFNs. Here, we demonstrate a mechanism by which TLR signaling controls cell proliferation and survival. We show that TLR3 and TLR4 can induce cell cycle entry via TRIF, which targets the cell cycle inhibitor p27kip1 for relocalization, phosphorylation by cyclin/cdk complexes, and proteasome degradation. These events are antagonized by type I IFN induced by the TRIF pathway. Furthermore, in human dendritic cells treated with TLR3, TLR4, or TLR5 ligands, we demonstrate that IFN signaling modulates p27kip1 degradation and apoptosis, identifying an immunoregulatory “switching” function of type I IFNs. These findings reveal a previously uncharacterized function of TLR signaling in cell proliferation and survival.
78 citations
TL;DR: The L83V polymorphism previously associated with risk for cancer progression in some populations, showed significant activity, comparable to that of the E6 prototype, in reducing p53 and Bax levels, however, the difference from the prototype was not statistically significant.
Abstract: Genetic variations in the E6 oncogene have been associated with different risk for cancer progression. In the present study, the functional significance of human papillomavirus (HPV) polymorphism in the E6 oncogene was investigated. Ten HPV16 E6 variants containing amino acid substitutions in the N-terminal region of E6 were evaluated for different biological and biochemical activities in human keratinocytes, the target cells for HPV infection. Western blot analyses of primary foreskin human keratinocytes or immortalized human keratinocytes, stably transduced with the E6 variants, revealed reduced p53 and Bax levels in all E6 expressing cultures. The reduction induced by most E6 proteins was at similar levels and comparable to the reduction induced by the E6 prototype. The ability of the proteins to induce serum/calcium-differentiation resistant colonies in primary keratinocytes was more variable. Overall activities of the variants ranged between 0.24- and 2.18-fold of the E6 prototype activity. The I27R/L83V variant showed the lowest activity whereas the R8Q variant showed the highest activity. The L83V polymorphism previously associated with risk for cancer progression in some populations, showed significant activity, comparable to that of the E6 prototype, in reducing p53 and Bax levels. Furthermore, this variant showed enhancement in the ability to induce colonies resistant to serum/calcium-triggered differentiation, however, the difference from the prototype was not statistically significant. This, and augmentation of other described functions might result in differences in L83V pathogenicity.
41 citations
TL;DR: This study further evaluates the molecular role of IFI16 in the development of HNSCCs and shows that the levels of the interferon‐inducible protein I FI16 inversely correlate with cancer grade.
Abstract: Background. In a previous analysis of head and neck squamous cell carcinomas (HNSCCs), we showed that the levels of the interferon-inducible protein IFI16 inversely correlate with cancer grade. In this study, we further evaluate the molecu- lar role of IFI16 in the development of HNSCCs. Methods. The effect of IFI16 expression was evaluated by its retroviral restoration in an IFI16-negative HNSCC-derived cell line, HNO136. Growth rate and soft agar colony formation were evaluated. The effect of IFI16 restoration in cells exposed to dox- orubicin was also analyzed. Results. IFI16 restoration resulted in the inhibition of both cell growth and in vitro transforming activity and increased doxorubicin- induced cell death by accumulating the cells at the G2/M phase. Conclusion. In agreement with our previous in vivo data, IFI16 appears to be involved in maintaining the normal growth of epithelial cells, whereas its downregulation may contribute to
17 citations
TL;DR: The data show that in vitro properties of these E7 proteins correlate with the epidemiological classification of HPV26, 53 and 66 as HPV types with an intermediate risk for cervical cancer development.
16 citations
TL;DR: The data show that Dok1 expression and structure are affected in a subset of Burkitt's lymphoma samples, suggesting its possible role in this type of cancer.
15 citations
TL;DR: Human papillomavirus infection among 100 oesophageal cancer cases in the People’s Republic of China is studied.
Abstract: Human papillomavirus infection among 100 oesophageal cancer cases in the People’s Republic of China Min Dai, Wei-dong Zhang, Gary M. Clifford, Tarik Gheit, Bao-chang He, Kristina M. Michael, Tim Waterboer, Pierre Hainaut, Massimo Tommasino and Silvia Franceschi* International Agency for Research on Cancer, Lyon, France Department of Epidemiology, Zhengzhou University, Zhengzhou, China Department of Epidemiology, Fujian Medical University, Fuzhou, China Infection and Cancer Program, German Cancer Research Center (DKFZ), Heidelberg, Germany
12 citations
TL;DR: It is observed that HPV77 E7 associated with pRb with a lower affinity than HPV16 E7, promoting weakly its degradation, in contrast to several E7s of mucosal HPV types.
2 citations