High-throughput sequencing analysis of a "hit and run" cell and animal model of KSHV tumorigenesis

PLoS Pathog. 2020 Jun 30;16(6):e1008589. doi: 10.1371/journal.ppat.1008589. eCollection 2020 Jun.


Kaposi's sarcoma (KS), is an AIDS-associated neoplasm caused by the KS herpesvirus (KSHV/ HHV-8). KSHV-induced sarcomagenesis is the consequence of oncogenic viral gene expression as well as host genetic and epigenetic alterations. Although KSHV is found in all KS-lesions, the percentage of KSHV-infected (LANA+) spindle-cells of the lesion is variable, suggesting the existence of KS-spindle cells that have lost KSHV and proliferate autonomously or via paracrine mechanisms. A mouse model of KSHVBac36-driven tumorigenesis allowed us to induce KSHV-episome loss before and after tumor development. Although infected cells that lose the KSHV-episome prior to tumor formation lose their tumorigenicity, explanted tumor cells that lost the KSHV-episome remained tumorigenic. This pointed to the existence of virally-induced irreversible oncogenic alterations occurring during KSHV tumorigenesis supporting the possibility of hit and run viral-sarcomagenesis. RNA-sequencing and CpG-methylation analysis were performed on KSHV-positive and KSHV-negative tumors that developed following KSHV-episome loss from explanted tumor cells. When KSHV-positive cells form KSHV-driven tumors, along with viral-gene upregulation there is a tendency for hypo-methylation in genes from oncogenic and differentiation pathways. In contrast, KSHV-negative tumors formed after KSHV-episome loss, show a tendency towards gene hyper-methylation when compared to KSHV-positive tumors. Regarding occurrence of host-mutations, we found the same set of innate-immunity related mutations undetected in KSHV-infected cells but present in all KSHV-positive tumors occurring en exactly the same position, indicating that pre-existing host mutations that provide an in vivo growth advantage are clonally-selected and contribute to KSHV-tumorigenesis. In addition, KSHV-negative tumors display de novo mutations related to cell proliferation that, together with the PDGFRAD842V and other proposed mechanism, could be responsible for driving tumorigenesis in the absence of KSHV-episomes. KSHV-induced irreversible genetic and epigenetic oncogenic alterations support the possibility of "hit and run" KSHV-sarcomagenesis and point to the existence of selectable KSHV-induced host mutations that may impact AIDS-KS treatment.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Cell Transformation, Viral*
  • DNA Methylation*
  • Gene Expression Regulation, Neoplastic*
  • Gene Expression Regulation, Viral*
  • Herpesvirus 8, Human* / genetics
  • Herpesvirus 8, Human* / metabolism
  • High-Throughput Nucleotide Sequencing
  • Mice
  • Neoplasms, Experimental* / genetics
  • Neoplasms, Experimental* / metabolism
  • Neoplasms, Experimental* / pathology
  • Neoplasms, Experimental* / virology
  • Plasmids* / genetics
  • Plasmids* / metabolism
  • Sarcoma, Kaposi* / genetics
  • Sarcoma, Kaposi* / metabolism
  • Sarcoma, Kaposi* / pathology
  • Sarcoma, Kaposi* / virology