TISSUE-SPECIFIC STEM CELLS Functional Remodeling of Benign Human Prostatic Tissues In Vivo by Spontaneously Immortalized Progenitor and Intermediate Cells MING JIANG,a DOUGLAS W. STRAND,a SUZANNE FERNANDEZ,a YUE HE,b YAJUN YI,c ANDREAS BIRBACH,d QINGCHAO QIU,c JOHANNES SCHMID,d DEAN G. TANG,e SIMON W. HAYWARDa,b Departments of aUrological Surgery, bCancer Biology, and cGenetic Medicine, Vanderbilt University Medical Center and Vanderbilt-Ingram Cancer Center, Nashville, Tennessee, USA; dDepartment of Vascular Biology and Thrombosis Research, Center for Biomolecular Medicine and Pharmacology, Medical University of Vienna, Vienna, Austria; eDepartment of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, Smithville, Texas, USA Key Words. Tissue-speciﬁc stem cells • Progenitor cells • Tissue regeneration • Cell transplantation • Self-renewal ABSTRACT Tissue remodeling or regeneration is believed to initiate from multipotent stem and progenitor cells. We report here the establishment of two spontaneously immortalized adult non-tumorigenic human prostate epithelial cell lines, NHPrE1 and BHPrE1. NHPrE1 (CD133high/CD44high/ OCT4high/PTENhigh) was characterized as a putative progeni- tor cell, and BHPrE1 (p63high/p53high/p21(WAF1)high/RBhigh) was characterized as a putative epithelial intermediate cell. Genomic analysis demonstrated an abnormal karyotype with genomic rearrangements including PTEN ampliﬁcation in NHPrE1 and CTNNB1 (b-catenin) ampliﬁcation in BHPrE1 cells. Embedded three-dimensional culture of NHPrE1 showed greater branching than BHPrE1. A tissue recombi- nation-xenografting model was utilized to compare remodel- ing of human prostatic tissues in vivo. A series of tissue recombinants, made by mixing different ratios of human prostatic epithelial cells and inductive rat urogenital sinus mesenchyme, were grafted to the renal capsule of severe combined immunodeﬁcient mice. Both cell lines were able to regenerate benign secretory ductal-acinar architecture in vivo, containing intact basal and luminal epithelial layers conﬁrmed by the expression of appropriate CK proﬁles. Prostate-speciﬁc antigen, 15-lipoxygenase-2, androgen recep- tor, and NKX3.1 proteins were appropriately expressed in the regenerated epithelia. Regeneration of benign prostatic glandular structures could be achieved using as few as 10 NHPrE1 cells, whereas 200,000 BHPrE1 cells were required to achieve prostatic architecture. This suggests a greater pro- portion of progenitor/stem cells in NHPrE1 than in BHPrE1. These cell lines provide important data on progenitor and in- termediate cell phenotypes and represent signiﬁcant new tools for the elucidation of molecular mechanisms of human prostatic regeneration, pathogenesis, and carcinogenesis. STEM CELLS 2010;28:344–356 Disclosure of potential conﬂicts of interest is found at the end of this article. INTRODUCTION The human prostate is a canalized ductal-acinar structure that develops from solid cords initiated by the budding of endo- dermal epithelium of the embryonic urogenital sinus (UGS) [1, 2]. These cords grow into the surrounding mesenchyme, then branch and canalize to form a secretory ductal-acinar structure with tall columnar secretory luminal cells and a ﬂat- tened basal epithelium. Concurrent with epithelial differentia- tion, the adjacent stroma develops to form a predominantly ﬁbromuscular phenotype [3, 4]. Differentiated basal and lumi- nal epithelial cells express appropriate cytokeratins (CK) and biomarkers characteristic of a molecularly deﬁnitive lineage commitment. Basal cells express p63 and CKs 5 and 14, whereas luminal cells express CKs 8 and 18 as well as spe- cies- and prostate-speciﬁc secretory proteins including pros- tate-speciﬁc antigen (PSA) and prostatic acid phosphatase in humans [5]. Prostate cancer (Pca) is characterized by a loss of basal epithelial cells [6]. During development, testicular androgens elicit paracrine interactions between epithelium and stroma in a series of coordinated molecular events, which occurs in a proximal to distal direction in the growing pros- tate [2, 7, 8]. The anatomy, histology, and molecular proﬁling of human prostate have obvious differences from those of rodents [9]. These include the expression of speciﬁc proteins, Author contribution: M.J.: Conception and design, collection and/or assembly of data, data analysis and interpretation, manuscript writing, ﬁnal approval of manuscript; D.S., S.F., and Y.H.: Collection and/or assembly of data; Y.Y. and Q.Q.: Collection and/or assembly of data; A.B. and J.S.: Collection and/or assembly of data; D.T.: Provision of study material or patients; S.H.: Financial support, conception and design, data analysis and interpretation, manuscript writing, ﬁnal approval of manuscript. Correspondence: Ming Jiang, M.D., Ph.D., Department of Urological Surgery, A-1302 MCN, Vanderbilt University Medical Center, Nashville, TN 37232-2765, USA. Telephone: 615-343-5984; Fax: 615-322-8990; e-mail: ming.jiang.1@vanderbilt.edu; or Simon W. Hayward, Ph.D., Department of Urological Surgery, A-1302 MCN, Vanderbilt University Medical Center, Nashville, TN 37232-2765, USA. Telephone: 615-322-5823; Fax: 615-322-8990; e-mail: simon.hayward@vanderbilt.edu. Received September 18, 2009; accepted for publication December 7, 2009; ﬁrst published online in STEM CELLS EXPRESS January 28, 2010. VC AlphaMed Press 1066-5099/2009/ $30.00/0 doi: 10.1002/stem.284 STEM CELLS 2010;28:344–356 www.StemCells.com