Kaposi's sarcoma-associated herpesvirus induction of chromosome instability in primary human endothelial cells.

Chromosome instability contributes to the multistep oncogenesis of cancer cells. Kaposi's sarcoma (KS), an angiogenic vascular spindle cancer of endothelial cells, displays stage advancement with lesions at early stage being hyperproliferative, whereas lesions at late stage are clonal or multiclonal and can exhibit a neoplastic nature and chromosome instability. Although infection with KS-associated herpesvirus (KSHV) has been associated with the initiation and promotion of KS, the mechanism of KS neoplastic transformation remains unclear. We show that KSHV infection of primary human umbilical vein endothelial cells induces abnormal mitotic spindles and centrosome duplication. As a result, KSHV-infected cells manifest chromosome instability, including chromosomal misalignments and laggings, mitotic bridges, and formation of micronuclei and multinucleation. Our results indicate that KSHV infection could predispose cells to malignant transformation through induction of genomic instability and contributes to the development of KS.