Fig. 8: Nilotinib reverses and prevents resistance, in vivo.
a–c Mel1617-BR (BR) or parental cells (Mel) were injected s.q. into SCID-beige mice, and when average tumor size was 200 mm3, Mel1617-BR mice were randomized to vehicle (Veh, n = 12), nilotinib (nilo, n = 12; 33 mg/kg, b.i.d.), PLX4720 (PLX, 25 mg/kg, n = 12), or combination (n = 11). Parental xenografts were treated with vehicle or PLX (n = 5/group). Mice were euthanized when control tumors ≅1500 mm3 (or were ulcerated). a Individual mouse tumor volumes over time. b Kaplan–Meier survival analysis comparing tumor doubling across groups. Percentage of mice not reaching the tumor doubling endpoint. Logrank p = 0.00451. PLX + nilo vs. vehicle, p = 0.0202; PLX + nilo vs. nilo, p = 0.0093; PLX + nilo vs. PLX, p = 0.0202 using pairwise comparisons and Holm’s multiple comparison adjustment. c PLX + nilotinib-treated mice were divided into responding (n = 7) and non-responding (n = 4) groups, and mean ± SEM tumor volumes plotted. Some SEMs are too small to visualize. One-way ANOVA followed by Sidak’s multiple comparisons test for responding vs. other groups. veh, p = 0.0104; nilo, p = 0.0004; PLX, p = 0.0027; non-responding, p = 0.0116. d–g M14-BMR (BMR) or parental M14 (M14) xenografts were established in nude mice. BMR xenografts treated with vehicle, nilotinib (33 mg/kg, b.i.d.), dabrafenib (25 mg/kg/day) + trametinib (0.15 mg/kg/day) (D/T), or D/T + nilotinib (n = 12/group) when tumors were 200 mm3. Parental xenografts were treated with vehicle or D/T (n = 5/group). d Mean ± SEM tumor volumes. Vehicle/nilotinib-treated mice and four mice from D/T and D/T + nilo groups were euthanized on d35. Linear mixed model analysis: for all comparisons, p = 3e−04. e H&E and MYC immunohistochemical staining of representative tumors (d) from n = 4 mice/group. f Survival analysis. Time-to-tumor doubling on d35. Percentage of mice not reaching the tumor doubling endpoint. Logrank p = 1.07e−06. Pairwise comparisons and Holm’s: p < 6.46e−05 for all groups. g D/T and D/T + nilotinib mice (n = 8/group) were followed long term. Mean ± SEM tumor volumes are shown. Dotted line indicates loss of euthanized mice (4/group). h, i In vivo prevention study. M14 parental tumors were established in nude mice, and mice treated with the indicated drugs. Vehicle, n = 5; nilo, n = 6; D/T, n = 11; DT + nilo, n = 12. h Mean ± SEM tumor volumes. Dotted lines indicate loss of mice (high tumor volume and/or tumor ulceration). i Percentage of mice that developed resistance/relapse (tumors ≥ 300 mm3). Fisher’s exact test, p = 0.0000673 (two sided). Additional data and statistics related to these experiments are shown in Supplementary Fig. 8.
