Characterization of c-Kit expression and activation in KSHV-infected endothelial cells

Virology. 2009 Aug 1;390(2):174-85. doi: 10.1016/j.virol.2009.05.011. Epub 2009 Jun 6.

Abstract

Kaposi's sarcoma (KS) herpesvirus (KSHV) is the etiological agent of several immunodeficiency-linked cancers, including KS. Our previous work showed that the proto-oncogene c-kit is upregulated in KSHV-infected endothelial cells (ECs), as well as in KS lesions. We show here that KSHV-dependent induction of both c-kit mRNA and protein requires the establishment of a latent infection and that this upregulation occurs in primary DMVECs as well as in immortalized DMVECs (eDMVECs). Interestingly, we find that while the lymphatic EC (LEC) subpopulation exhibits KSHV-induced c-Kit upregulation, the blood EC (BEC) subpopulation does not. Despite this upregulation of c-Kit, receptor activation and phosphorylation of downstream effectors such as MAP Kinase Erk 1/2 and GSK-3 still requires the addition of exogenous c-Kit ligand, stem cell factor (SCF). These data indicate that KSHV does not induce constitutive c-Kit signaling, but instead upregulates c-Kit receptor levels, thus allowing infected ECs to respond to endogenous and exogenous SCF. Nonetheless, inhibition of either c-Kit activation or its downstream effectors reverses the characteristic spindle phenotype of infected eDMVECs. Together, these results contribute to our overall understanding of the role that the c-kit proto-oncogene plays in KS pathogenesis.

Publication types

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

MeSH terms

  • Cell Line
  • Cells, Cultured
  • Endothelial Cells / virology*
  • Herpesvirus 8, Human / physiology*
  • Humans
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins c-kit / biosynthesis*
  • Stem Cell Factor / metabolism
  • Virus Latency

Substances

  • MAS1 protein, human
  • Proto-Oncogene Mas
  • Stem Cell Factor
  • Proto-Oncogene Proteins c-kit