Kaposi's sarcoma (KS) is the most common cancer in AIDS patients associated with infection by Kaposi's sarcoma-associated herpesvirus (KSHV). KS is often involved with oral cavity, and oral KSHV infection is necessary for the development of oral KS and virus spread. Despite antiretroviral therapy, KS remains common among HIV-infected patients. Existing antiviral and anticancer therapies are ineffective for eliminating persistent KSHV infection and for treating KSHV-induced cancer. Because KSHV latent infection is necessary for its long-term persistent infection and for KS development, identificatio of factors essential for KSHV latent infection can lead to the development of novel therapeutic approaches for oral KSHV persistent infection and malignancies. We have developed three novel systems to address these challenges: 1) KSHV-induced cellular transformation of primary human bone marrow mesenchymal stem cells (MSCs), 2) KSHV persistent infection in the oral cavity in NOD/SCID IL2R?-/- (NSG) humanized mice, and 3) KSHV persistent infection in primary human oral epithelial cells, gingiva MSCs and dental pulp MSCs. Using these models, we have found extensive epigenetic reprograming of cellular chromatins and gene expression networks in latent KSHV- infected cells. Furthermore, we have identified histone modifiers including polycomb repressive complex 2 (PRC2) proteins and class III histone deacetylases sirtuins as the critical factors for the survival of latent KSHV-infected cells. Significantly, targeting PRC2 proteins and sirtuins induce massive cell death of latent KSHV-infected cells including KSHV-transformed cells but have minimal cytotoxicity to uninfected cells. Based on these results, our hypothesis is that histone modifiers mediate the survival of latent KSHV-infected oral cells, and therefore inhibition of these targets can kill latent KSHV-infected cells resulting in effective therapeutic intervention for oral KSHV persistent infection and KSHV-induced cancer. We propose to identify the histone modifiers essential for KSHV latent infection in oral cells (Aim 1); delineate the mechanisms by which histone modifiers mediate the survival of latent KSHV infected oral cells (Aim 2); and therapeutically clear oral KSHV persistent infection and inhibit KSHV-induced oral cancer in animal models by targeting specific histone modifiers (Aim 3). The proposed project is significant because it will delineate the essential histone modifiers for oral KSHV persistent infection and pathogenesis, and identify effective inhibitors for therapeutic inhibition of these novel targets. The results will provide insights int the mechanisms of oral KSHV persistent infection and KSHV-induced oncogenesis. The outcomes can also be applied to other oral persistent viral infections and virus-induced cancer.

Public Health Relevance

Infections by herpesviruses are for life-long, causing many important diseases including cancers. There is no vaccine against most of human herpesviruses or effective approach for eliminating their long-term persistent infections. Using one of the human herpesvirus, KSHV, which causes several types of devastating cancer, as an example, we will develop novel antiviral/anticancer agents for treating viral cancer and for clearing persistent herpesviral infections, including persistent oral infections.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
5R01DE025465-06
Application #
9756364
Study Section
Special Emphasis Panel (ZDE1)
Program Officer
Wang, Chiayeng
Project Start
2018-08-01
Project End
2020-04-30
Budget Start
2019-05-01
Budget End
2020-04-30
Support Year
6
Fiscal Year
2019
Total Cost
Indirect Cost
Name
University of Pittsburgh
Department
Genetics
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
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Gruffaz, Marion; Zhou, Shenghua; Vasan, Karthik et al. (2018) Repurposing Cytarabine for Treating Primary Effusion Lymphoma by Targeting Kaposi's Sarcoma-Associated Herpesvirus Latent and Lytic Replications. MBio 9:
Cheng, Fan; Ramos da Silva, Suzane; Huang, I-Chueh et al. (2018) Suppression of Zika Virus Infection and Replication in Endothelial Cells and Astrocytes by PKA Inhibitor PKI 14-22. J Virol 92:
Jeon, Hyungtaek; Yoo, Seung-Min; Choi, Hyo Sun et al. (2017) Extracellular vesicles from KSHV-infected endothelial cells activate the complement system. Oncotarget 8:99841-99860
He, Meilan; Tan, Brandon; Vasan, Karthik et al. (2017) SIRT1 and AMPK pathways are essential for the proliferation and survival of primary effusion lymphoma cells. J Pathol 242:309-321
Yuan, Hongfeng; Tan, Brandon; Gao, Shou-Jiang (2017) Tenovin-6 impairs autophagy by inhibiting autophagic flux. Cell Death Dis 8:e2608
Li, W; Hu, M; Wang, C et al. (2017) A viral microRNA downregulates metastasis suppressor CD82 and induces cell invasion and angiogenesis by activating the c-Met signaling. Oncogene 36:5407-5420

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