EXPRESSION OF INTERLEUKIN-15 (IL-15) IN HUMAN RHABDOMYOSARCOMA, OSTEOSARCOMA AND EWINGS-SARCOMA

Interleukin 15 (IL-15) is a recently discovered cytokine that stimulat es lymphocyte proliferation and migration via a trimeric receptor shar ing the beta and gamma signal transducing chains with the IL-2 recepto r. IL-15 is typically produced by normal cells that do not release IL- 2, but little information is currently available on human tumors. To a ssess whether human musculo-skeletal sarcomas produce IL-15, we analyz ed surgical specimens and cell lines obtained from rhabdomyosarcoma, o steosarcoma and Ewing's sarcoma. IL-15 mRNA was present in 9/9 surgica l specimens (3 Ewing's sarcomas, 5 osteosarcomas and 1 rhabdomyosarcom a). The analysis of a panel of cell lines (7 derived from Ewing's sarc oma, 12 from osteosarcoma and 5 from rhabdomyosarcoma) showed that all rhabdomyosarcoma and osteosarcoma cell lines expressed IL-15 mRNA at levels ranging from low to high, while Ewing's sarcoma cells contained little or no IL-15 message. ELISA assays showed IL-15 release in a su bset of rhabdomyosarcomas and osteosarcomas, but not in Ewing's sarcom a. The highest production of IL-15, in the picogram/ml range, was foun d in rhabdomyosarcoma cell lines RH30 and RD. (C) 1997 Wiley-Liss, Inc .