Figure 6. Functional remodeling of benign human prostatic architecture in vivo. A: Gross images of tissue recombinants grafted under the sub- renal capsule of SCID mice for three months using different ratios of NHPrE1 epithelial cells {10 (a, b), 5,000 (c, d), 50,000(e, f), 100,000 (g, h)} with rat UGM. B: Histology of tissue recombinants made by NHPrE1 plus rat UGM using 10, 5,000 or 600,000 epithelial cells. Note the well differentiated tall columnar secretory cells and expression of secretion into the glandular lumen (position of host kidney noted). Scale bar ¼ 100 lm (low mag.) or 50 lm (high mag.). C: Immunohistochemical detection of GFP, NKX3.1, AR and p63 show functionally differentiated prostatic regeneration in tissue recombinants made with NHPrE1-EGFP cells plus rat UGM. NKX3.1 and AR are expressed throughout the lumi- nal epithelium and in some stromal cells, p63 marks the basal epithelium. Scale bar ¼ 50 lm. D: Double immunoﬂuorescence staining was used to detect p63 and human prostate speciﬁc biomarker PSA or 15-LOX-2 in tissue recombinants made by NHPrE1 or BHPrE1 cells with rat UGM. p63 was conﬁrmed to the basal cells in mature ducts while PSA and 15-LOX-2 were expressed in well differentiated luminal epithelial cells. b- catenin was seen by immunoﬂuorescence to be localized in epithelial cellular membrane in mature NHPrE1- or BHPrE1-tissue recombinants. Scale bar ¼ 50 lm. Abbreviations: BHPrE1, a spontaneously immortalized benign human prostate epithelial cell line from BHPrE0; EGFP, enhanced green ﬂuorescent protein; GFP, green ﬂuorescent protein; NHPrE1: a spontaneously immortalized ‘‘normal’’ human prostate epithelial cell line, that was established from parent NHPrE0 cells; UGM, urogenital sinus mesenchyme.