Cancers attributable to human papillomavirus (HPV) infections are the most common HIV-associated malignancies around the world; specifically cervical cancer in sub-Saharan Africa and anal cancer among long- term survivors in the United States. The mechanisms responsible for these increased odds are not completely understood. In contrast to other HIV-associated malignancies, the incidence of cervical cancer is not entirely related to the depth of CD4+ T-cell count nadir, suggesting that a mechanism in addition to inadequate CD4+ help predisposes HIV-infected individuals to cervical and other HPV-associated cancers. Our group and others made the important observation that HIV integration into certain genes appears to modulate host gene expression to favor proliferation and persistence of infected T-cells. Emerging data show that HIV integration can skew the differentiation of nave CD4+ T-cells into T regulatory cells, providing further mechanistic insights to the immunopathology of persistent HIV infection. The aforementioned observations combined with the recognized role of T regulatory cells in cervical cancer led to our overarching hypothesis that HIV integration into host genes that modulate T regulatory cells are integral to the development of cervical cancer in HIV- infected individuals through alterations of tumor-based immunity. To evaluate this hypothesis, we will utilize a well established collaboration with the Uganda Cancer Institute to define HIV integration into genes associated with T regulatory cell function in HPV-infected cervical tissues. We will enroll HIV-infected and -uninfected Ugandan women with a positive cervical cancer screening test (visual inspection with acetic acid), and identify those with high-risk HPV infections for study. In the first Aim, we will compar HIV integration sites, density of T regulatory cells with HIV proviruses and expression of checkpoint molecules in the cervical tissue of women who have progressed to pre-cancer/carcinoma with HIV-infected women with spontaneous clearance of high- risk HPV infections. Furthermore, the proteome pathways of T regulatory cells and cytotoxic T cells will be compared between HIV-infected women with progression to cervical neoplasia with -uninfected women with high-risk HPV who are likely to clear their HPV. In the second Aim, we will evaluate host gene function of CD4+ T-cells clones with proviruses infiltrating the cervical dysplasia. Specifically, we will characterize the T-cell markers of these cell clones using cells from the clone detected in the peripheral blood. HIV-infected circulating CD4+ T-cells from the clones infiltrating the cervical dysplasia will be expanded from in mini-cultures of single HIV infected cells using a novel technology to comprehensively characterize the HIV provirus and surrounding host genome. Finally, the ability to recapitulate transcriptome and phenotypic changes in nave CD4+ T-cells by insertion of the HIV LTR promoter into genomic sites found to be disrupted in cervical cancer cases will be evaluated. Together these data will inform whether and how HIV integration into host genes predisposes to an increased risk of HPV-associated cancers, and point to novel interventions to treat persistent HPV infections.
This proposal seeks to determine whether a novel mechanism may be in part responsible for the high incidence of HPV-associated cancers in persons with HIV infection. Using a unique cohort of HIV-infected women with cervical dysplasia in Uganda, we will characterize the frequency, sites and immunologic impact of HIV integration into host genes associated with cancer and cellular proliferation by comparing dysplastic cervical tissue from women who have squamous cell carcinoma of the cervix with women who spontaneously regress high-grade dysplasia. The knowledge gained from this proposal could directly improve therapeutic approaches to secondary prevention and treatment of HPV-associated cancers worldwide.
