Summary of the Role of IL-6 and IGF-I in the Panel of MM Cell Lines
| . | Cell Line . | Response to IGF-I . | Response to Anti– IGF-IR Antibodies . | Population Doubling Time (h) . | Reference . |
|---|---|---|---|---|---|
| IL-6–independent | LP-1 | + | + | 24 | 29 |
| EJM | − | + | 60 | 30 | |
| Karpas 707 | + | + | 60-72 | 31 | |
| HL407L | + | + | 36 | 27 | |
| U-266-1984 | − | + | 48 | 28 | |
| IL-6–dependent | U-1958 | + | + | 60-72 | 32 |
| HL407E | + | + | 48 | 27 | |
| U-266-1970 | − | + | 60 | 26 |
| . | Cell Line . | Response to IGF-I . | Response to Anti– IGF-IR Antibodies . | Population Doubling Time (h) . | Reference . |
|---|---|---|---|---|---|
| IL-6–independent | LP-1 | + | + | 24 | 29 |
| EJM | − | + | 60 | 30 | |
| Karpas 707 | + | + | 60-72 | 31 | |
| HL407L | + | + | 36 | 27 | |
| U-266-1984 | − | + | 48 | 28 | |
| IL-6–dependent | U-1958 | + | + | 60-72 | 32 |
| HL407E | + | + | 48 | 27 | |
| U-266-1970 | − | + | 60 | 26 |
Response to IGF-I refers to growth stimulation by exogenous IGF-I, while response to anti–IGF-IR antibodies refers to growth inhibition of cells growing in normal culture medium (without added IGF-I). Cells were cultured with different concentrations of IGF-I or anti–IGF-IR antibodies for 120 hours, harvested, and counted using trypan blue exclusion. Data on LP-1, EJM, and Karpas 707 were previously published,3 while data on the other cell lines are based on previously unpublished observations.