Proliferation characteristics of ovarian cancer cells. Proliferation of normal cells and cancer cell lines 1, 2, and 3 in serum free medium (SFM) with (A) and without (B) the addition of IGF-1 (20 ng/ml). The proliferation of cancer cell lines is approximately 20-fold over that of normal cells (P<0.05). (C) Effect of antisense (AS) IGF-1R mRNA oligonucleotides on the growth of cancer cells. Cancer cells were maintained in SFM as described in the “Methods” section. AS or sense oligonucleotides (S,40 ng/ml) were added to the medium for 24 h before the addition of IGF-1 (20 ng/ml) at time zero. Cells were counted at the indicated times. The data represent the mean of triplicate determinations from one of three representative experiments.