Figure 5.

Combined eribulin and abemaciclib treatment enhances in vivo antitumor activity in palbociclib-resistant breast cancer xenograft. (A) Drug dosing scheme for the in vivo experimental procedure. (B) Mean tumor growth curve of MCF7-PR xenograft treated with eribulin, abemaciclib, or a combination of those two. Tumor volumes were monitored every 2–3 days. p-value was calculated with two-way analysis of variance after Bonferroni correction on day 28 after drug treatment initiation. Data are presented as the mean ± standard error of the mean (SEM). (C) The mice body weight graph indicated that drug treatment did not cause any bodyweight loss. (D) Xenografted tumors were harvested from each group of mice at the end of the experiment. Dotted circles indicated complete tumor regression. (E) The weights of the tumors were measured. p-values were calculated by Student’s t-test. Data are presented as the mean ± SEM. NS indicates not significant. All the student’s- t-test performed were two-tail and unpaired. (F,G) Western blot using MCF7-PR xenograft after 28 days of treatment showed a greater PLK1 suppression and cleaved caspase-3 induction in the combination group than eribulin or abemaciclib single-treatment groups. Full length blots (F,G) are presented in Figure S5.