Figure 6. MAOA is essential for the growth of prostate tumor xenografts by regulating EMT, hypoxia, and ROS.

(A) LNCaP, C4-2, ARCaP_M, or MPC3 cells that stably express a MAOA-targeting shRNA (shMAOA) or a scrambled shRNA (shCon) were injected s.c. into male nude mice (n = 4–7 mice for each group; details are given in Supplemental Table 1) for the growth of tumor xenografts. Tumor growth was determined by measurement of tumor volume, tumor weight, and the frequency of tumor formation. The graphs show the mean (± SEM) tumor size and tumor-free percentages at the indicated times. *P < 0.05, **P < 0.01. (B) H&E and IHC analysis of Ki-67, MAOA, E-cadherin, vimentin, HIF1α, and VEGF-A expressions in LNCaP (shCon and shMAOA) tumor xenografts. Representative images from 5 separate samples are shown. Original magnification, ×400; scale bars: 20 μm. (C) Quantification of percentage of Ki-67⁺ tumor cells in paired LNCaP and C4-2 tumor xenografts from 5 distinct images of each tumor sample (n = 5 tumor samples for each group). Data represent the mean ± SEM. *P < 0.05, **P < 0.01. (D) Determination of MAOA enzymatic activity in paired LNCaP and C4-2 tumor xenografts. Data represent the mean ± SEM from all tumors obtained at mouse necropsy (n = 5–12 tumors for each group; details are given in Supplemental Table 1). **P < 0.01. (E) Determination of H₂O₂ generation rate in intact mitochondria isolated from paired LNCaP and C4-2 tumor xenografts (n = 3 tumor samples for each group) by Amplex Red hydrogen peroxide assay. Data represent the mean ± SEM. *P < 0.05.