Essential Roles for Soluble Virion-Associated Heparan Sulfonated Proteoglycans and Growth Factors in Human Papillomavirus Infections

A subset of human papillomavirus (HPV) infections is causally related to the development of human epithelial tumors and cancers. Like a number of pathogens, HPV entry into target cells is initiated by first binding to heparan sulfonated proteoglycan (HSPG) cell surface attachment factors. The virus must then move to distinct secondary receptors, which are responsible for particle internalization. Despite intensive investigation, the mechanism of HPV movement to and the nature of the secondary receptors have been unclear. We report that HPV16 particles are not liberated from bound HSPG attachment factors by dissociation, but rather are released by a process previously unreported for pathogen-host cell interactions. Virus particles reside in infectious soluble high molecular weight complexes with HSPG, including syndecan-1 and bioactive compounds, like growth factors. Matrix mellatoproteinase inhibitors that block HSPG and virus release from cells interfere with virus infection. Employing a co-culture assay, we demonstrate HPV associated with soluble HSPG-growth factor complexes can infect cells lacking HSPG. Interaction of HPV-HSPG-growth factor complexes with growth factor receptors leads to rapid activation of signaling pathways important for infection, whereas a variety of growth factor receptor inhibitors impede virus-induced signaling and infection. Depletion of syndecan-1 or epidermal growth factor and removal of serum factors reduce infection, while replenishment of growth factors restores infection. Our findings support an infection model whereby HPV usurps normal host mechanisms for presenting growth factors to cells via soluble HSPG complexes as a novel method for interacting with entry receptors independent of direct virus-cell receptor interactions

Current trends in initial management of oropharyngeal cancer: the declining use of open surgery.

Item does not contain fulltextThe widespread availability of novel primary treatment approaches against oropharyngeal cancers has provided several potentially curative surgical and nonsurgical treatment options for patients, generating both hope and controversy. As treatment is usually curative in intent, management considerations must include consideration of primary tumor and nodal disease control as well as long-term toxicities and functional outcomes. Anatomical and functional organ preservation (speech and deglutition) remains of paramount importance to patients with oropharyngeal cancer and the physicians involved in their care, accounting for the growing popularity of chemoradiotherapy and transoral surgical techniques for this indication. These novel approaches have greatly diminished the role of open surgery as initial therapy for oropharyngeal cancers. Open surgery which is often reserved for salvage on relapse, may still be an appropriate therapy for certain early stage primary lesions. The growing treatment armamentarium requires careful consideration for optimal individualized care. The identification of oncogenic human papillomavirus as a predictive and prognostic marker in patients with oropharyngeal cancer has great potential to further optimize the choice of treatment. In this review, novel primary therapies against oropharyngeal squamous cell carcinoma are presented in the context of anatomical, quality of life, and emerging biological considerations