Figure 2

Effect of interleukin-6 (IL-6) overexpression on in vitro and in vivo cell growth of LNCaP sublines before and after androgen ablation. (A) In vitro proliferation of LNCaP/Co (control vector-only transfected cell line) and LNCaP/IL-6#1 (IL-6-transfected cell line) cultured in the standard medium was evaluated by counting in triplicate the number of cells in each cell line daily. Bars, s.d. (B) Following culture in standard medium for 3 days, the medium was replaced with steroid hormone-depleted charcoal-stripped medium, and in vitro proliferation of LNCaP/Co and LNCaP/IL-6#1 under androgen-deprived condition was evaluated by counting in triplicate the number of cells in each cell line daily. Bars, s.d. ** and *, differ from LNCaP/Co (P<0.01 and P<0.05, respectively). (C) Intact nude mice were subcutaneously given 5 × 106 cells of LNCaP sublines in the right flank on day 0. Tumour size was expressed as the product of the maximal diameter multiplied by the perpendicular diameter. Bars, s.d. of tumour size; 10 mice per group. ** and *, differ from LNCaP/Co (P<0.01 and P<0.05, respectively). (D) Following subcutaneous injection of LNCaP sublines, nude mice were castrated on day 0 when the tumour size reached 80 mm2 or greater. Tumour size in castrated mice was then serially measured as described above. Bars, s.d. of tumour size; 10 mice per group. ** and *, differ from LNCaP/Co (P<0.01 and P<0.05, respectively).