Differential Inductive Signaling of CD90 Prostate Cancer-Associated Fibroblasts Compared to Normal Tissue Stromal Mesenchyme Cells

Abstract

Prostate carcinomas are surrounded by a layer of stromal fibroblastic cells that are characterized by increased expression of CD90. These CD90(+) cancer-associated stromal fibroblastic cells differ in gene expression from their normal counterpart, CD49a(+)CD90(lo) stromal smooth muscle cells; and were postulated to represent a less differentiated cell type with altered inductive properties. CD90(+) stromal cells were isolated from tumor tissue specimens and co-cultured with the pluripotent embryonal carcinoma cell line NCCIT in order to elucidate the impact of tumor-associated stroma on stem cells, and the 'cancer stem cell.' Transcriptome analysis identified a notable decreased induction of smooth muscle and prostate stromal genes such as PENK, BMP2 and ChGn compared to previously determined NCCIT response to normal prostate stromal cell induction. CD90(+) stromal cell secreted factors induced an increased expression of CD90 and differential induction of genes involved in extracellular matrix remodeling and the RECK pathway in NCCIT. These results suggest that, compared to normal tissue stromal cells, signaling from cancer-associated stromal cells has a markedly different effect on stem cells as represented by NCCIT. Given that stromal cells are important in directing organ-specific differentiation, stromal cells in tumors appear to be defective in this function, which may contribute to abnormal differentiation found in diseases such as cancer.

Electronic supplementary material: The online version of this article (doi:10.1007/s12307-010-0061-4) contains supplementary material, which is available to authorized users.

Keywords: Cancer stem cell; Prostate; Prostate cancer; Reversion-inducing cysteine-rich protein with Kazal motifs (RECK); Tumor-associated stroma.

Fig. 1

Expression profiles of stromal and stem cell genes in treated NCCIT. a Increased expression of prostate stromal cell-specific genes relative to untreated NCCIT was detected in co-cultures of NP stromal + NCCIT cells (labeled NP-NCCIT). Expression of these stromal genes was less pronounced in co-culture of CP stromal + NCCIT cells (CP-NCCIT). For example, PENK was not induced. Note the increase in tumor-associated stromal marker CD90/THY1. b The CP-NCCIT transcriptome dataset (first column) contains minimal signal for smooth muscle differentiation genes (CALD1, CNN1) present in the NP-NCCIT transcriptome (third column) compared to untreated NCCIT transcriptome (second column) in virtual Northern blot format (darker shades of boxes indicate higher mRNA levels with background ≤50 RMA units). c Higher expression of several stem cell genes was detected in CP-NCCIT relative to NP-NCCIT as well as in cultured CP stromal cells relative to NP stromal cells. d Virtual Northern blot format shows that for stem cell genes NANOG, SOX2, CD9 and THY1, expression was increased in CP-NCCIT compared to untreated NCCIT, whereas expression was decreased in NP-NCCIT

Fig. 2

Expression of RECK genes in prostate cancer. a Relative expression of RECK, TIMP1 and MMP9 induced by CP vs. NP stromal cells in NCCIT. The average array signal values for 2 experiments (NP1, NP2, CP1, CP2) are tabulated, which were used to generate the histogram. b Relative expression profile of genes involved in ECM remodeling in sorted stromal and epithelial cells from tumor vs. normal tissue. Positive values indicate up-regulation in cancer and negative values indicate down-regulation in cancer

Fig. 3

Schematic of RECK pathway in stromal–epithelial interaction in prostate cancer. Decreased RECK expression leads to activation of MMPs and degradation of ECM proteins allowing dissemination of tumor cells. Virtual Northern blot format shows array signals for MMP9, HRAS and RECK in NP stromal vs. CP stromal cells (1 and 2 from two different specimens) and for TIMPs in NP epithelial vs. CP cancer cells