In vivo evaluation of TRIM21 potentiates the antimyeloma effect of bort. A total of 5 × 10⁶ TRIM21 KD or OE ARP-1 cells were subcutaneously injected into nonobese diabetic (NOD)-severe combined immunodeficiency (SCID) mice (n = 24). The tumor size was measured with a caliper, and PBS or bort (0.5 mg/kg) was injected every 3 to 4 days when the established tumors reached ∼100 to 130 mm³ on day 12. (A) Tumor volume of each group shown as mean ± SD. (B) Xenografts were excised and photographed on day 26. (C-D) Immunohistochemistry analysis of TRIM21, ATG-5, c-Caspase-3, and LC3 on tumor tissue sections from each group. Summary measurement of signals (E) and representative images of chemiluminescence (F) in the TRIM21 KD, TRIM21 OE and control group. Original magnification: 200×. Scale bars: 100 μm. (∗P < .05; ∗∗P < .01; ∗∗∗P < .001).