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. 2014 Dec 8;9(12):e114530.
doi: 10.1371/journal.pone.0114530. eCollection 2014.

The molecular signature of the stroma response in prostate cancer-induced osteoblastic bone metastasis highlights expansion of hematopoietic and prostate epithelial stem cell niches

Berna C Özdemir  1 , Janine Hensel  1 , Chiara Secondini  1 , Antoinette Wetterwald  1 , Ruth Schwaninger  1 , Achim Fleischmann  2 , Wolfgang Raffelsberger  3 , Olivier Poch  4 , Mauro Delorenzi  5 , Ramzi Temanni  6 , Ian G Mills  7 , Gabri van der Pluijm  8 , George N Thalmann  1 , Marco G Cecchini  1
Affiliations

The molecular signature of the stroma response in prostate cancer-induced osteoblastic bone metastasis highlights expansion of hematopoietic and prostate epithelial stem cell niches

Berna C Özdemir et al. PLoS One. .

Abstract

The reciprocal interaction between cancer cells and the tissue-specific stroma is critical for primary and metastatic tumor growth progression. Prostate cancer cells colonize preferentially bone (osteotropism), where they alter the physiological balance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption, and elicit prevalently an osteoblastic response (osteoinduction). The molecular cues provided by osteoblasts for the survival and growth of bone metastatic prostate cancer cells are largely unknown. We exploited the sufficient divergence between human and mouse RNA sequences together with redefinition of highly species-specific gene arrays by computer-aided and experimental exclusion of cross-hybridizing oligonucleotide probes. This strategy allowed the dissection of the stroma (mouse) from the cancer cell (human) transcriptome in bone metastasis xenograft models of human osteoinductive prostate cancer cells (VCaP and C4-2B). As a result, we generated the osteoblastic bone metastasis-associated stroma transcriptome (OB-BMST). Subtraction of genes shared by inflammation, wound healing and desmoplastic responses, and by the tissue type-independent stroma responses to a variety of non-osteotropic and osteotropic primary cancers generated a curated gene signature ("Core" OB-BMST) putatively representing the bone marrow/bone-specific stroma response to prostate cancer-induced, osteoblastic bone metastasis. The expression pattern of three representative Core OB-BMST genes (PTN, EPHA3 and FSCN1) seems to confirm the bone specificity of this response. A robust induction of genes involved in osteogenesis and angiogenesis dominates both the OB-BMST and Core OB-BMST. This translates in an amplification of hematopoietic and, remarkably, prostate epithelial stem cell niche components that may function as a self-reinforcing bone metastatic niche providing a growth support specific for osteoinductive prostate cancer cells. The induction of this combinatorial stem cell niche is a novel mechanism that may also explain cancer cell osteotropism and local interference with hematopoiesis (myelophthisis). Accordingly, these stem cell niche components may represent innovative therapeutic targets and/or serum biomarkers in osteoblastic bone metastasis.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. The gene expression pattern changes in bones xenografted with osteoinductive PCa cells.
A. Flow chart outlining experimental (blue) and bioinformatics (grey) steps adopted to define a complete (OB-BMST) and a curated (“Core” OB-BMST) stroma response signature (orange). The first two experimental steps constitute the tissue compartment-specific transcriptional profiling (TCTP). B. Heatmap showing differentially expressed probe-sets between xenografted (C4-2B and VCaP) and control (Ep156T, intact and sham) bones. The expression level is color-coded: low expression is represented in blue, whereas high expression is represented in red. C. Venn diagram showing the number of overlapping and unique genes differentially expressed in C4-2B (FDR = 1E-05) and VCaP (FDR = 3E-05) xenografted bones. The sum of differentially expressed genes is referred to as the OB-BMST. D. Scatter plot showing log2 fold change of differentially expressed genes in C4-2B and VCaP xenografts. E. Top 30 up-regulated genes of the OB-BMST derived from C4-2B (black bars) and VCaP (grey bars) xenografted bones.
Figure 2
Figure 2. The Core OB-BMST represents the fraction putatively specific for the BM/B response to osteoinductive PCa cells.
A. Four-set Venn diagram showing the comparison of primary MCa, PCa with the OB-BMST after subtraction of gene signatures derived from desmoplastic, wound-healing, inflammatory and non-osteotropic cancers ( =  “Curated 2” OB-BMST, sum of grey and red areas). The red shaded area is referred to as “Core OB-BMST” (complete list reported in S2 Table), genes of the grey area represent a potential osteotropic signature (complete list reported in S6 Table). B. Top 30 up-regulated genes of the Core OB-BMST derived from C4-2B (black bars) and VCaP (grey bars) xenografted bones.
Figure 3
Figure 3. Enriched GO terms and protein interaction networks within the “common” OBMST and Core OB-BMST.
GO terms enriched in the “common” OB-BMST (FDR≤5.50E-03) (A) and in the “common” Core OB-BMST (FDR≤5.0E-01) (B). Protein interaction networks by STRING analysis in the “common” OB-BMST (C) and in the “common” Core OB-BMST (D). The thickness of lines correlates positively with the confidence score that was obtained for each protein interaction. Abbreviation: FDR, false discovery rate.
Figure 4
Figure 4. The OB-BMST and Core OB-BMST contain genes from stem cell niche signatures.
Venn diagrams showing the number of overlapping OB-BMST (A and B) and Core OB-BMST (C and D) genes with gene signatures derived from the hematopoietic (A and C) and the developing prostate (B and D) stem cell niches. Relative expression levels of Ptn, Epha3, Cd109 and Slit3. E. VCaP (grey, n = 3) and C4-2B (black, n = 4) intra-osseous xenografts; values are shown as fold change (mean ± SD) relative to contralateral and sham-operated bones. F. VCaP (grey, n = 5) orthotopic xenografts; values are shown as fold change (mean ± SD) relative to intact and sham-operated prostate. G. VCaP (grey, n = 3) and C4-2B (black, n = 5) subcutaneous xenografts; values are shown as fold change (mean ± SD) relative to intact skin. H. PC-3 (light grey, n = 6) intra-osseous xenografts; values are shown as fold change (mean ± SD) relative to contralateral and sham-operated bones (n = 3–4). *, P<0.01; **, P<0.001; ***, P<0.0001; ****, P<0.0001. Abbreviations: HSCs, hematopoietic stem cells; UGM urogenital mesenchyme; Ptn, pleiotrophin; Epha3, Eph receptor a3; Slit3, slit homolog 3.
Figure 5
Figure 5. PTN, EPHA3 and FSCN1 protein expression is induced in human bone metastatic, but not primary PCa.
Immunohistochemical detection of PTN (A, D, G and J), EPHA3 (B, E, H and K) and FSCN1 (C, F, I and L) in normal bone (A, B and C), in osteoblastic PCa bone metastasis (D, E and F), in normal prostate (G, H and I) and in primary PCa (J, K and L). Insets represent a higher magnification of selected areas. Scale bar = 50 µm. Abbreviations: PTN, pleiotrophin; EPHA3, Eph receptor A3; FSCN1, fascin homolog 1.
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References

    1. Weckermann D, Muller P, Wawroschek F, Harzmann R, Riethmüller G, et al. (2001) Disseminated cytokeratin positive tumor cells in the bone marrow of patients with prostate cancer: detection and prognostic value. J Urol 166:699–703. - PubMed
    1. Bubendorf L, Schopfer A, Wagner U, Sauter G, Moch H, et al. (2000) Metastatic patterns of prostate cancer: an autopsy study of 1,589 patients. Hum Pathol 31:578–583. - PubMed
    1. Sleeman JP (2012) The metastatic niche and stromal progression. Cancer Metastasis Rev 31:429–440 10.1007/s10555-012-9373-9 - DOI - PMC - PubMed
    1. Logothetis CJ, Lin S-H (2005) Osteoblasts in prostate cancer metastasis to bone. Nat Rev Cancer 5:21–28 10.1038/nrc1528 - DOI - PubMed
    1. Guise T (2010) Examining the Metastatic Niche: Targeting the Microenvironment. Semin Oncol 37:S2–S14 10.1053/j.seminoncol.2010.10.007 - DOI - PubMed

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Grants and funding

This work was supported by grants from the European Commission (CANCURE-2006-020970 and FP7 Marie Curie ITN PRO-NEST-238278) and from the Swiss National Foundation (3100A0-116237). B.C.Ö. received funding from the OncoSuisse MD/PhD Scholarship (323630-128865/1). Part of the costs for the microarray hybridization was supported by the Department of Clinical Research, University of Bern, Switzerland. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.