Figure 6. Partial dependence of EGFR^L858R-induced lung adenocarcinomas on Erbb3.

(A) Model for tamoxifen induced deletion of Erbb3. Mutant EGFR^L858R tetra transgenic mice were fed doxycycline to induce tumors. When the tumor size reached a minimum volume of 100 mm³, experimental mice (Nkx2.1-Cre^ERT2+) were administered tamoxifen by oral gavage at the doses of 250 mg/day for two days. Control animals were Nkx2.1-Cre^ERT2 negative and treated with tamoxifen or Nkx2.1-Cre^ERT2 positive treated with corn oil. After tamoxifen treatment, mice were imaged using MRI weekly for 4 weeks. The tumor burden for each group is shown in Fig. 6B. Mouse lungs were collected at the end of 4 weeks or when moribund and tumor extracts were analyzed by Western blot for the indicated proteins (Fig. 6C).