FIG. 8.

J2-KO1 cells display delayed tumorigenicity in nude mice. (A) Athymic nude mice were injected intraperitoneally with 5 × 10⁴ J2-WT1 or J2-KO1 cells. The animals were monitored for histiocytic tumor development (indicated by peritoneal swelling and morbidity) and were sacrificed upon onset of severe disease symptoms. The data (percent surviving animals) are combined from two independent experiments, each containing 10 to 13 animals. (B) Peritoneal tumor cells were collected from mice showing signs of disease and placed in culture with M-CSF. One wt (J2-WT1.T20) and two mutant (J2-KO1.T32 and J2-KO1.T37) tumor-derived cell lines were established and then assayed for survival in the presence or absence of M-CSF (NF, no factor). Viable cells were determined at 0, 24, and 48 h by neutral red dye uptake. The data are the average of three independent experiments. (C) IGF-I mRNA expression was measured by RPA in the parental J2-WT1 and J2-KO1 cells and in tumor-derived cell lines (J2-WT1.T20, J2-KO1.T32, and J2-KO1.T37). IGF-I transcripts were quantitated by phosphorimaging and normalized to GAPDH and are expressed as arbitrary units (au).