The human papillomavirus-16 E7 oncoprotein exerts antiapoptotic effects via its physical interaction with the actin-binding protein gelsolin

Mileo, Anna Maria; Abbruzzese, Claudia; Vico, Carmen; Bellacchio, Emanuele; Matarrese, Paola; Ascione, Barbara; Federico, Antonio; Bianca, Stefano Della; Mattarocci, Stefano; Malorni, Walter; Paggi, Marco G.

doi:10.1093/carcin/bgt192

Cited by 9 publications

(13 citation statements)

References 43 publications

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“…p.e., postexposure. cycle, as it was shown that HPV16 E7 interacts with gelsolin during postinfective carcinogenesis, resulting in increased cell survival (73). Besides gelsolin, the membrane glycoprotein dysadherin had no or only a minor influence on HPV16 PsV entry but could still be relevant for HPV16 morphogenesis.…”

Section: Discussionmentioning

confidence: 97%

The Cytoskeletal Adaptor Obscurin-Like 1 Interacts with the Human Papillomavirus 16 (HPV16) Capsid Protein L2 and Is Required for HPV16 Endocytosis

Wüstenhagen

Hampe

Boukhallouk

et al. 2016

J Virol

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The human papillomavirus (HPV) capsid protein L2 is essential for viral entry. To gain a deeper understanding of the role of L2, we searched for novel cellular L2-interacting proteins. A yeast two-hybrid analysis uncovered the actin-depolymerizing factor gelsolin, the membrane glycoprotein dysadherin, the centrosomal protein 68 (Cep68), and the cytoskeletal adaptor protein obscurin-like 1 protein (OBSL1) as putative L2 binding molecules. Pseudovirus (PsV) infection assays identified OBSL1 as a host factor required for gene transduction by three oncogenic human papillomavirus types, HPV16, HPV18, and HPV31. In addition, we detected OBSL1 expression in cervical tissue sections and noted the involvement of OBSL1 during gene transduction of primary keratinocytes by HPV16 PsV. Complex formation of HPV16 L2 with OBSL1 was demonstrated in coimmunofluorescence and coimmunoprecipitation studies after overexpression of L2 or after PsV exposure. We observed a strong colocalization of OBSL1 with HPV16 PsV and tetraspanin CD151 at the plasma membrane, suggesting a role for OBSL1 in viral endocytosis. Indeed, viral entry assays exhibited a reduction of viral endocytosis in OBSL1-depleted cells. Our results suggest OBSL1 as a novel L2-interacting protein and endocytosis factor in HPV infection. IMPORTANCEHuman papillomaviruses infect mucosal and cutaneous epithelia, and the high-risk HPV types account for 5% of cancer cases worldwide. As recently discovered, HPV entry occurs by a clathrin-, caveolin-, and dynamin-independent endocytosis via tetraspanin-enriched microdomains. At present, the cellular proteins involved in the underlying mechanism of this type of endocytosis are under investigation. In this study, the cytoskeletal adaptor OBSL1 was discovered as a previously unrecognized interaction partner of the minor capsid protein L2 and was identified as a proviral host factor required for HPV16 endocytosis into target cells. The findings of this study advance the understanding of a so far less well-characterized endocytic pathway that is used by oncogenic HPV subtypes. Human papillomaviruses (HPVs) are small, nonenveloped DNA viruses that infect dividing basal keratinocytes of skin and mucosa via microlesions of the tissue. HPV is capable of inducing benign epithelial warts on the skin and mucosa, and infection with a high-risk HPV type may cause cervical and other anogenital and oropharyngeal cancers (1, 2). Cervical cancer is the third most common cancer in women worldwide and is associated with HPV infection, more precisely with high-risk HPV types such as HPV16, HPV18, and HPV31 (3). HPV is composed of a viral capsid with the major capsid protein L1, the minor capsid protein L2, and the viral genome. One icosahedral capsid contains 360 copies of L1, which can self-assemble to 72 pentamers, and up to 72 copies of the minor capsid protein L2, located inside the L1 shell (4-6). The capsid proteins L1 and L2 are key players in early events of infection, such as virus binding at the plasma membrane, cell entry, and t...

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Section: Discussionmentioning

confidence: 97%

The Cytoskeletal Adaptor Obscurin-Like 1 Interacts with the Human Papillomavirus 16 (HPV16) Capsid Protein L2 and Is Required for HPV16 Endocytosis

Wüstenhagen

Hampe

Boukhallouk

et al. 2016

J Virol

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“…On this basis, and in the light of our previous results [11], we assessed, by means of IVM analysis and Fluorescence Resonance Energy Transfer (FRET), the occurrence of a protein-protein interaction between E7 and GSN. The results obtained by IVM (Figure 3A) clearly showed a co-localization (yellow staining in “merge” micrograph) of E7 with GSN in SiHa (second column) and CaSki cells (third column), which was undetectable in the E7 negative C-33A cells (first column).…”

Section: Resultsmentioning

confidence: 99%

“…To study the effects of the expression of the sole E7 oncoprotein, HPV-null C-33A cells were transfected in order to express the wild type E7 oncoprotein (E7 wt) or one of its deletion mutants E7Δ62–66 and E7Δ71–75, both characterized for their impaired ability to physically interact with the GSN molecule [11]. …”

Section: Resultsmentioning

confidence: 99%

“…Moreover, in a comparable keratinocyte cell model, we demonstrated that E7 can bind GSN and hinder its severing function, thus increasing the intracellular level of polymeric actin [11]. Accordingly, E7 has also been implicated in microfilament cytoskeleton integrity and function by acting on Rho GTPases, a family of small GTPases (e.g.…”

Section: Discussionmentioning

confidence: 99%

“…In a previous paper, we described the physical interaction between the E7 oncoprotein from the high-risk HPV16 strain (HPV16 E7, henceforth E7) and the actin-binding protein gelsolin (GSN) [11], one of the most potent members of the actin-severing gelsolin/villin superfamily. GSN acts as a key regulator of actin filament assembly and disassembly, binds to the barbed ends of actin filaments and prevents monomer exchange (end-blocking or capping).…”

Section: Introductionmentioning

confidence: 99%

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Interaction between the human papillomavirus 16 E7 oncoprotein and gelsolin ignites cancer cell motility and invasiveness

et al. 2016

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The viral oncoprotein E7 from the “high-risk” Human Papillomavirus 16 (HPV16) strain is able, when expressed in human keratinocytes, to physically interact with the actin severing protein gelsolin (GSN). In a previous work it has been suggested that this protein-protein interaction can hinder GSN severing function, thus leading to actin network remodeling. In the present work we investigated the possible implications of this molecular interaction in cancer cell metastatic potential by analyzing two different human CC cell lines characterized by low or high expression levels of HPV16 DNA (SiHa and CaSki, respectively). In addition, a HPV-null CC cell line (C-33A), transfected in order to express the HPV16 E7 oncoprotein as well as two different deletion mutants, was also analyzed. We found that HPV16 E7 expression level was directly related with cervical cancer migration and invasion capabilities and that these HPV16 E7-related features were associated with Epithelial to Mesenchymal Transition (EMT) processes. These effects appeared as strictly attributable to the physical interaction of HPV16 E7 with GSN, since HPV16 E7 deletion mutants unable to bind to GSN were also unable to modify microfilament assembly dynamics and, therefore, cell movements and invasiveness. Altogether, these data profile the importance of the physical interaction between HPV16 E7 and GSN in the acquisition of the metastatic phenotype by CC cells, underscoring the role of HPV16 intracellular load as a risk factor in cancer.

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Identification of Pivotal Cellular Factors Involved in HPV‐Induced Dysplastic and Neoplastic Cervical Pathologies

Mattarocci

Abbruzzese²,

Mileo³

et al. 2013

Journal Cellular Physiology

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Cervical carcinoma represents the paradigm of virus-induced cancers, where virtually all cervical cancers come from previous "high-risk" HPV infection. The persistent expression of the HPV viral oncoproteins E6 and E7 is responsible for the reprogramming of fundamental cellular functions in the host cell, thus generating a noticeable, yet only partially explored, imbalance in protein molecular networks and cell signaling pathways. Eighty-eight cellular factors, identified as HPV direct or surrogate targets, were chosen and monitored in a retrospective analysis for their mRNA expression in HPV-induced cervical lesions, from dysplasia to cancer. Real-time quantitative PCR (qPCR) was performed by using formalin-fixed, paraffin embedded archival samples. Gene expression analysis identified 40 genes significantly modulated in LSIL, HSIL, and squamous cervical carcinoma. Interestingly, among these, the expression level of a panel of four genes, TOP2A, CTNNB1, PFKM, and GSN, was able to distinguish between normal tissues and cervical carcinomas. Immunohistochemistry was also done to assess protein expression of two genes among those up-regulated during the transition between dysplasia and carcinoma, namely E2F1 and CDC25A, and their correlation with clinical parameters. Besides the possibility of significantly enhancing the use of some of these factors in diagnostic or prognostic procedures, these data clearly outline specific pathways, and thus key biological processes, altered in cervical dysplasia and carcinoma. Deeper insight on how these molecular mechanisms work may help widen the spectrum of novel innovative approaches to these virus-induced cell pathologies.

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The human papillomavirus-16 E7 oncoprotein exerts antiapoptotic effects via its physical interaction with the actin-binding protein gelsolin

Cited by 9 publications

References 43 publications

The Cytoskeletal Adaptor Obscurin-Like 1 Interacts with the Human Papillomavirus 16 (HPV16) Capsid Protein L2 and Is Required for HPV16 Endocytosis

The Cytoskeletal Adaptor Obscurin-Like 1 Interacts with the Human Papillomavirus 16 (HPV16) Capsid Protein L2 and Is Required for HPV16 Endocytosis

Interaction between the human papillomavirus 16 E7 oncoprotein and gelsolin ignites cancer cell motility and invasiveness

Identification of Pivotal Cellular Factors Involved in HPV‐Induced Dysplastic and Neoplastic Cervical Pathologies

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