Kaposi's sarcoma-associated herpesvirus infection of human bone-marrow-derived mesenchymal stem cells and their angiogenic potential.

Kaposi's sarcoma (KS) is a vascular tumor, and KS spindle cells express endothelial-cell-specific markers. Generally, it is believed that KS originates from endothelial cells. However, as various mesodermal-derived tissue markers are also expressed in KS spindle cells, the exact origin of KS still needs to be elucidated. Here, Kaposi's sarcoma-associated herpesvirus (KSHV) was used to infect human mesenchymal stem cells derived from bone marrow (hMSC-bm), and we investigated the angiogenic properties of these cells, which are one of the most important pathologic features of KS. KSHV-infected hMSC-bm showed latent infection and increased tube formation activity in vitro. In addition, the expression of endothelial-cell-specific markers and a growth factor that affects the angiogenesis of endothelial cells was induced in KSHV-infected cells. This study suggests that human mesenchymal stem cells might have important roles in KS pathogenesis.