Kaposi's Sarcoma-Associated Herpesvirus Can Productively Infect Primary Human Keratinocytes and Alter Their Growth Properties

Abstract

Kaposi's sarcoma (KS) is a multicentric vascular neoplasm involving the skin and mucosal surfaces and in aggressive cases may involve visceral organs and lymph nodes. KS lesions contain distinctive proliferating spindle cells, activated endothelial cells, fibroblasts, smooth muscle cells, and infiltrating inflammatory cells (35,39). Four different epidemiologic forms of Kaposi's sarcoma have been described, i.e., the classic, endemic, iatrogenic, and AIDS-related forms (22, 47).The gamma-2 herpesvirus KSHV, also known as human herpesvirus 8 (HHV8), has been detected in Ͼ95% of KS patients with all clinical forms of KS (22,34,47). KSHV/HHV8 DNA sequences are also present in primary effusion lymphomas (PEL) (8), a subset of B-cell lymphomas occurring more frequently in AIDS patients and in a significant percentage of patients with multicentric Castelman's disease (51). By in situ hybridization (5) and immunohistochemistry (7,15), the results of several studies have documented the presence of KSHV/HHV8 in spindle and endothelial cells in KS lesions. Reed et al. (38) by analysis of the expression of the latently expressed v-cyclin gene, noted the presence of KSHV/HHV8 DNA in scattered keratinocytes of the epidermis overlying cutaneous lesions. Positive signals were also detected in eccrine ductular epithelial cells and in spindle and endothelial cells lining the well-formed blood vessels within and surrounding KS lesions (38). Similar results were described by Foreman et al. (20), who detected KSHV/HHV8-positive signals by in situ PCR in basal keratinocytes in the area immediately above some of the later-stage (i.e., plaque or tumor) KS lesions. Epstein-Barr virus (EBV), the human herpesvirus most closely related to KSHV/HHV8, has been detected both serologically and histologically in epithelial cells (42,49,56). Epithelial cells of many tissues, including salivary glands and kidneys, support the replication of cytomegalovirus, another herpesvirus that can also infect human keratinocytes (58).In this study we investigated whether KSHV/HHV8 was capable of infecting primary cultures of human keratinocytes in vitro and analyzed the biological consequences of this infection. We demonstrate that KSHV/HHV8 can establish a productive infection in primary human keratinocytes and that viral particles purified from the supernatant of infected keratinocytes can infect other primary cells, such as human endothelial cells. Infection by KSHV/HHV8 resulted in alterations of the keratinocytes, including the development of a spindle-shaped cell morphology similar to that observed in other immortalized cell lines of epithelial origin (24), and the ability to form

Wild-Type Kaposi's Sarcoma-Associated Herpesvirus Isolated from the Oropharynx of Immune-Competent Individuals Has Tropism for Cultured Oral Epithelial Cells

“…The data are consistent with previous studies showing infection of epithelial cells derived from foreskin keratinocytes (3,9). Oral epithelial cell types ranging from primary to transformed were susceptible substrates.…”

Herpes simplex virus type-1 infection upregulates cellular promoters and telomerase activity in both tumor and nontumor human cells

“…25,26 Alteration of telomerase activity has been reported in cells infected with HIV and Kaposi's sarcoma-associated herpesvirus. [35][36][37] While HSV-1/2 are not considered carcinogenic, clinical correlation between HSV-2 and human carcinoma of cervix remains to be a debatable issue. [38][39][40][41][42][43][44][45][46] It is unclear whether the HSV-1-induced upregulation of telomerase activity showed in the present study could afford individual cell freedom from senescence, allow accumulations of the genetic changes and chromosome instability, and eventually lead to pathological state such as cancer.…”

The Kaposi’s Sarcoma-Associated Herpesvirus (KSHV/HHV-8) K1 Protein Induces Expression of Angiogenic and Invasion Factors

“…Several studies also have shown the presence of KSHV viral DNA in basal keratinocytes and epithelial cells surrounding and within the KS lesion (10,11). The detection of infectious viral particles in the saliva of KSHV-infected individuals has suggested that the epithelial cells in the oral mucosa or salivary glands are a source of the virus (12)(13)(14)(15), and it is thought that KSHV may infect epithelial cells in transit during initial infection (16). In tissue culture studies, KSHV is capable of infecting several types of cells, including human primary keratinocytes, B cells, and endothelial, epithelial, and fibroblast cells (17,18).…”