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Neoplastic AIDS-associated Kaposi's sarcoma cell line KSY-1 cannot transdifferentiate into capillaries
Y Lunardi-Iskandar1, N Wernert, T H Cong
1Institute of Human Virology, Medical Biotechnology Center, University of Maryland at Baltimore, USA.
Objective:
Kaposi's sarcoma (KS) is an acquired immunodeficiency syndrome (AIDS)-defining neoplasm histologically characterized by proliferation of spindle cells, inflammatory cells, and abundant neovascularization. When the malignant cell line KSY-1 derived from an AIDS-KS tumor is transplanted subcutaneously into nude mice, prominent neovascular features develop. Using this mouse model of neoplastic KS, we set out to determine, using c-ets 1 markers specific for mouse or human tissues, whether vascular growth and inflammatory infiltrate induced by the transplanted KSY-1 cells is of host cell or transplant origin.
Study Design/Methods:
KS tumors were induced by subcutaneous inoculation of 5 x 10(6) KSY-1 cells/200 microL in immunodeficient mice, and species-specific mouse and human riboprobes of the c-ets 1 protooncogene were used for in situ hybridization to define cell of origin.
Results:
Five different tumors were examined. Tissue sections from all cases were hybridized with radiolabeled riboprobes for the presence of both mouse and human c-ets 1 mRNA. Tumor cells were labeled with the human c-ets 1 probe, whereas neovascular and inflammatory tissues were of mouse origin.
Conclusions:
The finding that vascular but not tumor cells are of host origin supports the model of tumor-induced vascularization via a mechanism of tumor cell-derived cytokine-medicated pathogenesis.