PROJECT SUMMARY
Human papillomavirus (HPV)-driven oropharyngeal squamous cell cancer (OPSCC) has been rising in incidence
in the US and worldwide over the last four decades, particularly among young men. People with human
immunodeficiency virus (HIV) have an increased HPV-OPSCC risk as compared to HIV-negative individuals.
However, we have a very poor understanding of the mechanisms of persistent oral HPV infections and their
synergy with HIV co-infection, as well as the role of HIV in HPV-OPSCC induction and pathogenesis. The inability
to histologically characterize the early stages of HPV-induced OP tumorigenesis continues to hinder efforts to
diagnose OP precancerous lesions and assess cancer risk. Currently, there is no animal model for HPV-induced
oral infections and malignancies in the context of HIV-induced immunosuppression. In previous collaborative
efforts, the Ozbun and Traina-Dorge labs have successfully modeled cervical HPV infections and neoplasia in
female rhesus macaques (RMs) using Macca mulatta papillomavirus type 1 (MmPV1), a close relative of HPV16,
which causes 90-97% of HPV-OPSCC. In this R21 proposal, we will build on our prior work and collective
expertise with MmPV1, simian immunodeficiency virus (SIV), and non-human primate immunology to establish
a Rhesus macaque model of persistent oral HPV and HIV co-infection with which to study oral MmPV1 infections,
persistence, precancer, and OPSCC induction. This model is innovative and advantageous because both
MmPV1 and SIV recapitulate their respective infections and pathogenesis in RMs like their human counterparts:
MmPV1 is carcinogenic in its natural RM host, and these animals develop immunosuppression following SIV
infection. As HPV-OPSCCs are more common in males, we will expose immunosuppressed SIV-infected male
RMs to high-titer infectious MmPV1 virions in the tongue base, the palatine tonsil, and the soft palate. In AIM 1,
we will determine the oral infectivity and persistence of MmPV1 virions in SIV-infected and immunosuppressed
RMs. At timed intervals and in post-mortem tissues, we will assess MmPV1 viral loads and DNA persistence at
the sites of infection, and we will screen for localized viral shedding, preneoplastic oropharyngeal MmPV1
lesions, and disease progression. We will also measure circulating tumor MmPV1 DNA over time as a potential
biomarker of the onset of preneoplasia and/or OPSCC. In AIM 2, we will evaluate SIV- and MmPV1-induced
changes in RM biospecimens. At timed intervals, we will quantify plasma and saliva cytokine/chemokine levels
by Mesoscale immunoassays and assess HPV-disease-associated markers in cytobrush exfoliated OP cells and
endpoint post-mortem tissues by immunohistochemistry. These assays will identify biological pathways altered
by both viruses and determine potential disease correlates. Establishing a non-human primate model for OP PV
infections and precancers will facilitate expanded follow-up studies aimed at revealing mechanisms of MmPV1
infection, persistence, and progression from precancer to malignancy in the context of SIV-induced
immunosuppression; it will also promote efforts to diagnose and treat OP precancers.
