Stromal factors involved in human prostate cancer development, progression and castration resistance

Abstract

Purpose: To detect new predictive markers from the prostate cancer tissue, to study the expression by cultured cancer-associated fibroblasts (CAFs) of stromal factors implicated in prostate carcinogenesis, and to compare their expressions in localized, metastatic, castration-sensitive (CSCP), castration-resistant prostate tumors (CRCP) as well as in fibroblasts from benign prostatic hyperplasia (BPH).

Materials and methods: The genomic expression of 20 stroma-derived factors, including the androgen receptor (AR), growth factors (FGF2, FGF7, FGF10, HGF, TGFβ, PDGFB), protein implicated in invasion (MMP-2, MMP-9 and MMP-11), inflammation (IL-6, IL-17, STAT-3 and NFκB), stroma/epithelium interaction (CDH11, FAP, CXCL12 and CXCL14) and chaperones (HPA1A and HSF1), was evaluated in cultured fibroblasts both from BHP and prostate carcinomas (PCa). After isolation and culture of fibroblasts by biopsy specimens, RNA was isolated and genomic studies performed.

Results: Finally, 5 BPH and 37 PCa specimens were selected: clinically localized (19), metastatic (5), CSCP (7) and CRPC (6). Interleukin-17 receptor (IL-17RB) was highly expressed in CAFs compared with fibroblasts from BPH. However, metalloproteinase-2 and chemokine ligand 14 (CXCL14) were expressed at higher levels by fibroblasts from BPH. The fibroblastic growth factor-7 was highly expressed by CAFs from localized tumors, but metalloproteinase-11 in metastatic tumors. MMP-11, androgen receptor (AR) and heat-shock-70kda-protein-1A (HSPA1A) expressions were significantly higher in CAFs from CRPC.

Conclusions: These results demonstrate a CAFs heterogeneity among prostate carcinomas with regard to some molecular profile expressions that may be relevant in tumor development (IL-17RB), progression (MMP-11) and castration resistance (AR, MMP-11 and HSPA1A).

Keywords: Androgen deprivation therapy; Cancer-associated fibroblasts (CAFs); Castration-resistant prostate cancer; Metastatic cancer; Tumor stroma.

Fig. 1

Representative pictures of cell culture of fibroblasts during isolation process (a) 24 h to 72 h alter isolation. b One week after isolation. c Two different morphological types of cells, spindle-shaped cells could be fibroblasts, whereas round cells could be epithelial/tumoral cells. d Pure fibroblasts cell culture

Fig. 2

Boxplot comparing the median expression levels of IL-17RB, MMP-2 and CXCL14 in CAFs from prostate carcinomas and in BPH fibroblasts (median is shown as the center line in the boxes). IL17 receptor was highly expressed by fibroblasts from prostate cancer compared with fibroblasts from BPH (p: 0.03). However, MMP-2 (p: 0.02) and CXCL14 (p: 0.03) were expressed at higher levels by fibroblasts from BHP compared with fibroblasts from prostate cancer tissue. The comparisons analyzing the rest of factors were not significant. CAF: cancer-associated fibroblasts. IL-17RB: receptor of interleukin 17; MMP-2: matrix metalloprotease 2; CXCL14: chemokine ligand 14

Fig. 3

Boxplot comparing the median expression levels of FGF7 and MMP-11 in CAFs from localized and metastatic prostate carcinomas (median is shown as the center line in the boxes). Both factors were expressed at higher levels by CAFs from metastatic tumors compared with CAFs from localized tumors (p: 0.016). The comparisons analyzing the rest of factors were not significant. CAF: cancer-associated fibroblasts. FGF7: fibroblast growth factor 7; MMP-11: matrix metalloprotease 11

Fig. 4

Boxplot comparing the median expression levels of AR, MMP-11 and HSPA1A in CAFs from castration-sensitive and castration-resistant prostate carcinomas. AR (p: 0.022), MMP-11 (0.003) and HSPA1A (p: 0.007) were overexpressed by CAFs from CRPC tumors. The comparisons analyzing the rest of factors were not significant (p: 0.016). CAF: cancer-associated fibroblasts. AR: androgen receptor; matrix metalloprotease 11; HSPA1A: heat-shock 70kda protein 1A

Fig. 5

Representative pictures of immunohistochemistry staining. IL-17RB: receptor of interleukin 17; matrix metalloprotease 11; FGF7: fibroblast growth factor 7; AR: androgen receptor; HSPA1A: heat–shock 70kda protein 1A