Figure 3

PAT4 regulates the growth of HCT116 cells in vitro and in vivo. (a) Proliferation of clones of HCT116 cells stably transduced with one of two independent IPTG-inducible shRNA constructs targeting PAT4, namely shPAT4(4.8) and shPAT4(7.1), or the IPTG-inducible non-targeting control construct (shNT) was measured in the presence and absence of IPTG (n=3). (b and c) Mean growth curves (±s.e.m.) of human HCT116 tumour xenografts in immunodeficient mice carrying pools of cells transduced with shNT (b) with (empty circles) or without (filled squares) IPTG induction, or shPAT4-transduced HCT116 cells (c) with (empty squares, outlined in red) or without (filled squares) IPTG induction (n=7). Data in (b and c) were analysed by unpaired two-tailed independent Student’s t-test. (d and e) Kaplan–Meier survival curves of seven animals with and without IPTG induction of shNT- (d) and shPAT4-containing (e) HCT116 tumours; log-rank (Mantel–Cox) test: P=0.019 for (e). For shPAT4-inducible cells, all but one of the seven non-induced mice (filled squares) needed to be killed within 36 days (median survival time of 36 days), whereas all seven induced mice (empty squares, outlined in red) were killed from 38 days onwards with a median survival time of 50 days. Cell proliferation experiment was repeated three times. *P<0.05, **P<0.01.