Protein profile of basal prostate epithelial progenitor cells--stage-specific embryonal antigen 4 expressing cells have enhanced regenerative potential in vivo.

Thomas Höfner,Christian Eisen,Corinna Klein,Teresa Rigo‐Watermeier,Axel Haferkamp,Martin R Sprick

doi:10.1111/jcmm.12785

Abstract

The long‐term propagation of basal prostate progenitor cells ex vivo has been very difficult in the past. The development of novel methods to expand prostate progenitor cells in vitro allows determining their cell surface phenotype in greater detail. Mouse (Lin−Sca‐1+ CD49f+ Trop2high‐phenotype) and human (Lin− CD49f+ TROP2high) basal prostate progenitor cells were expanded in vitro. Human and mouse cells were screened using 242 anti‐human or 176 antimouse monoclonal antibodies recognizing the cell surface protein profile. Quantitative expression was evaluated at the single‐cell level using flow cytometry. Differentially expressed cell surface proteins were evaluated in conjunction with the known CD49f+/TROP2high phenotype of basal prostate progenitor cells and characterized by in vivo sandwich‐transplantation experiments using nude mice. The phenotype of basal prostate progenitor cells was determined as CD9+/CD24+/CD29+/CD44+/CD47+/CD49f+/CD104+/CD147+/CD326+/Trop2high of mouse as well as human origin. Our analysis revealed several proteins, such as CD13, Syndecan‐1 and stage‐specific embryonal antigens (SSEAs), as being differentially expressed on murine and human CD49f+ TROP2+ basal prostate progenitor cells. Transplantation experiments suggest that CD49f+ TROP2high SSEA‐4high human prostate basal progenitor cells to be more potent to regenerate prostate tubules in vivo as compared with CD49f+ TROP2high or CD49f+ TROP2high SSEA‐4low cells. Determination of the cell surface protein profile of functionally defined murine and human basal prostate progenitor cells reveals differentially expressed proteins that may change the potency and regenerative function of epithelial progenitor cells within the prostate. SSEA‐4 is a candidate cell surface marker that putatively enables a more accurate identification of the basal PESC lineage.

Highlights

Several model systems have been developed to understand the biological mechanisms involved during benign prostatic enlargement and prostate cancer, the latter being the most common type of cancer in men
Staining of murine and human cells revealed that basal PESCs, in addition to their expression CD49f+/TROP2high, are positive for a variety of additional markers (Tables 1 and 2)
Given the observed similarities of gene expression profiles of murine as well as human basal PESCs with the profiles of embryonic stem (ES) cells [11], we were interested in the specific expression of stage-specific embryonal antigens (SSEAs) we discovered in the cell surface protein screen

Summary

Introduction

Several model systems have been developed to understand the biological mechanisms involved during benign prostatic enlargement and prostate cancer, the latter being the most common type of cancer in men. 5% within all prostatic cells, which clearly complicates biological studies using these cells [5, 6]. Isolation and ex vivo expansion of basal PESCs have been further complicated by their dependence on poorly understood factors supplied by a prostate cell niche composed of smooth muscle cells, fibroblasts, neuroendocrine cells, and differentiating and mature prostate epithelial cells [7]. Significant progress had been made, culture techniques up to now allowed for only limited expansion of prostate epithelial cells (PrECs), which rapidly ceased to proliferate [8,9,10]. We recently discovered new methods to grow and expand both murine and human basal PESCs in serum- and feeder-free conditions [11].

Methods

Results

Conclusion