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. Author manuscript; available in PMC: 2022 Aug 1.
Published in final edited form as: Mol Cancer Ther. 2021 Dec 14;21(2):347–358. doi: 10.1158/1535-7163.MCT-21-0310

Figure 1. OB-Runx2 deficiency induces MM cell resistance to BTZ treatment in vivo.

Figure 1.

A, Schematic diagram of the tumor injection and treatment schedule for mice used in B-F. Five-week-old OB-Runx2+/+ and OB-Runx2−/− mice were i.v. injected with 5TGM1-Luc MM cells (down arrow) 1 week before treatment (left up arrow) with PBS or BTZ for 4 weeks. Blood and BM were collected at study end (right up arrow) for all analyses. B, Representative bioluminescence imaging of MM tumor-bearing OB-Runx2+/+ and OB-Runx2−/− mice after treatment (left); graphical representation of the luminescence intensity in each group (right) (n=5 mice/group). C, Quantification of serum IgG2bκ concentration in mice after treatment, measured by ELISA (in duplicate) (n=8–10 mice/group). D-F, BM cells harvested after treatment were analyzed by flow cytometry (n=7 mice/group). D, Representative plots (left) and the percentage of CD138+ (a membrane marker of 5TGM1 MM cells) MM cells detected among all B220+ B cells (right). E, Representative plots (left) and the percentage of Ki-67+ MM cells detected among CD138+ cells (right). F, Representative plots (left) and the percentage of BCL-2+ MM cells detected among CD138+ cells (right). G-H, 5TGM1-Luc MM cells were co-cultured with Pre-OBs harvested from the calvaria of newborn OB-Runx2+/+ or OB-Runx2−/− mice for 12 h before treatment with BTZ (0, 2.5, 5, or 10 nM) for 36 h. G, Representative bioluminescence imaging of luciferase activity in the 5TGM1-Luc MM cells after treatment (n=6 wells/group). H, Percent viability of 5TGM1-Luc MM cells, assessed by MTT assay, after treatment (in triplicate). I, Percent viability of OB-Runx2+/+ and OB-Runx2−/− Pre-OBs, assessed by MTT assay, after co-culture with 5TGM1-Luc MM cells for 48 h (n=24 wells/group). J, Percent viability of 5TGM1-Luc MM cells that were cultured for 24 h in medium mixed with BMS harvested from OB-Runx2+/+ or OB-Runx2−/− mice (no tumor injection) and PBS or BTZ (0, 2.5, 5, or 10 nM) (n=4/group). Data are presented as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.005, ****P < 0.001. ns, not significant.