Figure 2.

Cell growth of Smad4-reexpressing C4-II tet-on cell clones in vitro and in vivo. Long-term growth curves of the tet-on clones 18 and 28 and Smad4-reexpressing derivatives 18-2, 28-8 and 28-14 were established in doxycycline-containing media in the absence (a) and in the presence (b) of TGF-β. c) Short-term TGF-β effects on cell cycle distribution were assessed in the high-expressor clone 28-8 as compared to HaCaT cells used as a positive control. Bars show mean values +/- standard deviation from three cultures per cell line and condition in one experiment. Similar results were obtained in repeated experiments. d) Cell growth in vivo was assessed by subcutaneous injection in nude mice. The open bars and hatched bars show the mean tumour mass +/- standard deviation of 6 tumours, each, after 2 (clones 18 und 18-2) or 4 (clones 28, 28-8 and 28-14) weeks of growth in mice that received drinking water without and with the addition of doxycycline. Statistical significance is indicated. Similar results were obtained in repeated experiments.