Figure 4. Conditional ablation of Hdac1 and Hdac2 in Eμ-myc tumor cells delays tumor appearance in vivo.

(A) Experimental workflow scheme for transplantation experiments. Wild-type syngeneic recipient mice were sub-lethally irradiated (350 cGy of whole-body γ-irradiation) and transplanted intra-venously with lymph node-derived tumor cells from Hdac1^F/F; Hdac2^F/F; Actin-creER tg; Eμ-myc tg mice after development of overt malignancy. Recipient mice were treated with neomycin-supplemented drinking water 1 week before transplantation and up to 2 weeks post transplantation. At two weeks post transplantation, conditional KO was induced in one group of mice by intraperitoneal injection of 4-hydroxytamoxifen (4-OHT, 5 × 2 mg). Control mice were injected with vehicle. Mice were monitored for tumor onset and sacrificed when they reached termination criteria (see Material and Methods). (B) KPLM tumor-free survival curves of mice transplanted with tumor cells and treated with 4-OHT (n = 6) or vehicle (Ctr, n = 4) are shown. Survival is plotted as days post transplantation. The log-rank test was used to determine the level of significance between curves in the two groups.