Figure 9. DCEM1 inhibits oncogenic signaling and PCa tumor growth in vivo.

(A and B) 22RV1 cell xenografts were established in each flank of SCID mice and treated with DCEM1 (60 mg/kg body weight, i.p.) twice weekly. Tumors were harvested, photographed (A), and weighed (B) at 30 days, and results are presented in grams. (C) DEVDase activity was analyzed in 22RV1 xenograft tumor tissues following DCEM1 treatment and is represented as fold change compared to vehicle control. (D) 22RV1 xenograft tissues were sectioned and expression of Ki67, c-Myc, EZH2, and AR proteins was analyzed by immunohistochemistry. Scale bar: 50 μm. (E and F) PC-3 cell xenografts were established in each flank of SCID mice and treated with DCEM1 (60 mg/kg body weight, i.p.) twice weekly. Tumors were harvested, photographed (E), and weighed (F) at 35 days and results are presented in grams. (G) DEVDase activity was analyzed in PC-3 xenograft tumor tissue following DCEM1 treatment and is represented as fold change compared to control. (H) PC-3 xenograft tumor tissues were fixed and sections were used for in situ PLA to analyze HSP60-ClpP interactions in tumor tissue samples. Original magnification, x40. (I–L) TKO animals were treated with either vehicle or DCEM1 (60 mg/kg body weight) twice weekly from 10 weeks of age. Animals were sacrificed at 16 weeks of age and the whole genitourinary tract was harvested and weighed (I). Animals were imaged by MRI at 16 weeks of age and sacrificed. Prostate tissues and tumors were harvested, and representative H&E-stained images are shown (J). Scale bar 100 μm. Whole-tissue lysates from vehicle- or DCEM1-treated (60 mg/kg body weight) TKO tumor tissues were prepared and analyzed for HSP60 and ClpP expression (K) and c-Myc and EZH2 expression (L) by Western blotting. Data are mean ± SD. *P < 0.05, by 2-tailed Student’s t test (B, C, and F–I). Actin serves as loading control.