MACROPHAGE INFLAMMATORY PROTEIN (MIP)-1-ALPHA STEM-CELL INHIBITOR (SCI) DOES NOT AFFECT CLONAL GROWTH OF HUMAN SOLID TUMOR-CELL LINES IN-VITRO

MIP-1alpha is a member of a family of proinflammatory cytokines produc ed by activated macrophages which has been shown to be a negative regu lator of early hematopoietic stem cell progenitors. We report on resul ts testing recombinant human (rh) MIP-1alpha on the clonal growth of d ifferent human nonhematopoietic tumor cell lines in vitro. Cell lines tested included the following histologies: 7 glioblastomas, 1 neurobla stoma, 2 head and neck carcinomas, 4 lung carcinomas, 3 colorectal car cinomas, 1 gastric carcinoma, 1 pancreatic carcinoma, 1 breast carcino ma, 1 prostate carcinoma, 1 choriocarcinoma, 1 ovary carcinoma, 1 oste osarcoma, and 3 melanomas. MIP-1alpha (0, 2, 20, 200 ng/ml) was tested in human tumor cloning assays (HTCA) in agar-containing capillaries ( HTCAcap) and in mixtures of methylcellulose and agar (HTCAmix), repres enting assay systems with different plating efficiencies (PE). Tumor c ells were continuously exposed to the cytokine for the complete assay period. Clonal growth of none of the cell lines was significantly and reproducibly stimulated or inhibited by MIP-1alpha.