Figure 5

In vivo effects of the PC-3PEc cells. (A) SCID mice injected with PC-3PEc cells produced larger tumors, in size and in weight, than those obtained from mPC-3 cells at the same time points. (Student t test, p < 0.001, n = 15. Error bars refer to SD) Arrows: point of the primary tumors. Arrowheads: points of tumors developed distal from the injection sites (35 d post-injection). (B) Immunohistochemical analysis of mPC-3 induced and PC-3PEc induced tumors. PC-3PEc tumors documented with elevated expression of PEc compared with the wtPC-3 tumors. PC-3PEc tumors also contained an increased Ki-67 expression, which is a proliferation marker, and vimentin expression, while they had a decrease in E-cadherin expression as compared with mPC-3 tumors. In addition, PC-3PEc tumors presented decreased CKHMW levels and elevated chromogranin and synaptophysin levels compared with mPC-3 tumors, suggesting a possible neuroendocrine differentiation. Furthermore, we detected a relatively increased p53 expression in PC-3PEc tumors compared with the mPC-3 tumors. (C) Analysis of tumorigenesis in SCID mice injected with PC-3 cells after the silencing of the IGF-1Ec expression (PC-3 IGF-1Ec KD). These tumors presented slower tumor growth, compared with mPC-3 tumors and low tumorigenicity rate (20%, 2 out of 10). PC-3 IGF-1Ec KD tumors presented a similar expression pattern of prostate cancer markers examined in mPC-3 tumors, as observed by IHC.