THE IN-VIVO ENHANCEMENT OF IL-1-ALPHA RECEPTOR EXPRESSION ON POLYOMA-VIRUS TRANSFORMED TUMOR-DERIVED CELLS

The aim of this study was to evaluate expression of receptor for IL-1 on tumor-derived cells. The in vivo acquisition of an expression of a receptor for Fc gamma immunoglobulin on polyoma virus transformed cell s has been established by us. We investigated whether a receptor for t he IL-1 cytokine, like that for Fc gamma immunoglobulin, could also co ntribute to the heterogeneity of tumor cell population, as well as to its tumorigenic phenotype. Various clones of polyoma virus transformed 3T3 cells were passaged once in syngeneic mice and resulting tumors e xplanted and recultured. The expression of receptor for IL-1 was teste d on in vitro maintained clones (designated C for culture) and on tumo r derived clones (designated CTC -culture-tumor-culture). Expression w as determined using a I-125 radiolabeled ligand and confirmed by flow cytometry with anti-mouse IL-1 receptor (IL-1R) antibodies. Some CTC c lones expressed a higher level of IL-1 receptor than others. A positiv e correlation between the level of IL-1R and a metastatic phenotype wa s established with some tumor derived cells. A high IL-1R expressing t umor cell population, sorted by flow cytometry, was considerably more metastatic than the sorted low IL-1 expressing cells. IL-1R expression by tumor derived cells may, contribute to the metastatic phenotype of a tumor cell population.