485 MOLECULAR GENETIC COMPARISON OF CANCER AND NONCANCER-ASSOCIATED FIBROBLASTS IN PROSTATE CANCER

Abstract

INTRODUCTION AND OBJECTIVES: Over the last years the influence of surrounding cellular microenviroment on cancer cell development and behavior has gained more interest. In this context, cancer associated fibroblasts (CAFs) adjacent to a tumor seem to be important modulators of tumor cell proliferation, migration and invasion. So far, only little is known about the differences between CAFs and normal, non-cancer-associated fibroblasts (NAFs) in prostate cancer on a molecular level. Therefore the aim of the present study is to compare CAFs and NAFs from primary prostate cancer samples applying cytoand molecular genetic methods. METHODS: Small tissue pieces from cancerous and cancer free areas of the prostate were obtained from 5 prostatectomies by an uropathologist. CAFs and NAFs were selectively cultivated from these tissue samples in vitro. Cultivated fibroblasts were genetically characterized by CGH analysis. Additionally, expression of androgen receptor (AR), PDGRFA, SMA, TGF, -catenin and E-cadherin was quantitated in early cell cultures passages (passage 4-6) by qRT-PCR. Fibroblasts were further characterized by immunofluorescence staining with antibodies against SMA, vimentin and CK18. RESULTS: CGH analysis revealed cytogenetic normal karyotypes without any chromosomal alterations in NAFs as well as in CAFs. Immunostaining demonstrated a vimentin expression in all fibroblasts, whereas CK18 was not detected. Positivity for SMA staining varied between 5 and 50% in NAFs and only 5-10% in CAFs. In qRT-PCR analysis, decreased expression levels of SMA were also seen in the CAFs, whereas TGFand PDGFRA expression was markedly increased compared to NAFs. A high -catenin and low AR expression was at comparable levels in CAFs and NAFs, respectively. E-Cadherin was neither in CAFs nor in NAFs detectable. CONCLUSIONS: CAFs and NAFs seem not to have gross cytogenetic abnormalities in cancer bearing prostates. Nevertheless differences in gene expression of SMA, TGF, -catenin and PDGFRA can be detected, when comparing CAFs and NAFs. Whether this differential expression pattern is caused by the adjacent tumor cells or originated by the CAFs itself to modulate tumor cell behavior needs to be clarified in further studies. Our results underline the need for a better understanding of tumor stroma interactions and a possible role of stromal cells as potential therapeutic targets in prostate cancer.