INDUCTION OF PROSTATE CANCER CELL GROWTH, ANDROGENINDEPENDENCE AND BONE METASTASIS IN LNCAP CELLS BY HUMAN PROSTATE FIBROBLASTS OF DIFFERENT ZONAL ORIGIN

INDUCTION OF PROSTATE CANCER CELL GROWTH, ANDROGENINDEPENDENCE AND BONE METASTASIS IN LNCAP CELLS BY HUMAN PROSTATE FIBROBLASTS OF DIFFERENT ZONAL ORIGIN

13 BCAR1 EXPRESSION IN PROSTATE CANCER Fromont G.1 , Vallancien G.2 , Validire P.3 , Levillain P.4 , Cussenot O.5 1 CEREPP – University Hospital, Path...

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13 BCAR1 EXPRESSION IN PROSTATE CANCER Fromont G.1 , Vallancien G.2 , Validire P.3 , Levillain P.4 , Cussenot O.5 1 CEREPP – University Hospital, Pathology, Poitiers, France; 2 IMM, Urology, Paris, France; 3 IMM, Pathology, Paris, France; 4 University Hospital, Pathology, Poitiers, France; 5 CEREPP – Tenon Hospital, Urology, Paris, France INTRODUCTION & OBJECTIVES: Studies on breast and prostate cancer have suggested that the 16q23 locus contains a gene involved in tumor progression. Breast Cancer Antiestrogen Resistance 1 (BCAR1), which gene is located at 16q23, contributes to many cellular processes, including migration, survival and proliferation. In vitro experimentations have suggested an interaction between BCAR1 and both the growth factor receptor EGFR and the metastasis supressor KAI1. We analyzed BCAR1 expression profile in prostate cancer, together with 16q23 LOH status and both EGFR and KAI1 staining. MATERIAL & METHODS: BCAR1, EGFR and KAI1 expression was studied by immunohistochemistry on a tissu microarray containing 100 localized prostate cancers (LPC) and matched normal tissues, 15 hormone refractory prostate cancers (HRPC) and 15 lymph node metastasis (LNM). 48 of the LPC were also analyzed for 16q23 LOH status using highly informative microsatellite markers. RESULTS: BCAR1 staining was present in 25% of LPC, associated with higher Gleason score, and in 60% and 80% of respectively LNM and HRPC. BCAR1 expression was inversely correlated with 16q23 LOH status (p < 0.001), and was associated with high EGFR staining (p < 0.02) and negative KAI1 expression (p < 0.01). CONCLUSIONS: These datas suggest in vivo interactions between BCAR1 and key molecules involved in prostate cancer progression. BCAR1 seems to be regulated at least in part by genetic events, and the increase of BCAR1 expression during the natural history of prostate cancer strongly supports its role in processes leading to metastasis and hormono-independence.

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a2b 1HI /CD133+ PROSTATE CANCER STEM CELLS FROM HUMAN TUMOURS ARE HIGHLY TUMORIGENIC IN VIVO Collins A.1 , Hyde K.1 , Berry P.1 , Linton K.2 , Hamdy F.2 , Stower M.3 , Maitland N.1 1 University of York, Biology, York, United Kingdom; 2 University of Sheffield, Urology, Sheffield, United Kingdom; 3 York District Hospital, Urology, York, United Kingdom

INTRODUCTION & OBJECTIVES: Recent reports of cancer stem cells have prompted questions regarding the involvement of normal stem/progenitor cells in prostate tumour biology, their potential contribution to the tumour itself and whether they are the cause of tumour initiation and progression. A recent report from our laboratory identified the cancer stem cell as a2b 1hi/CD133+ (Collins et al., Cancer Res 2005; 65, 10946-10951). This in vitro study has now been extended to animals; the non-obese diabetic severe combined immunodeficient (NOD/SCID) mouse to determine whether prostate tumour initiation and maintenance originates from the stem cell. MATERIAL & METHODS: The phenotypes a2b1hi/CD133+ (stem cells), a2b1low/CD44+ (committed basal cells), CD44−/CD57+ (secretory luminal cells) were isolated from a2b1hi/CD133+-derived cultures of prostate cancer tissue, using a combination of cell adhesion to type I collagen and magnetic bead cell sorting for CD133. An unselected population was used as a control. Cells were injected into the ventral prostate, together with prostatic stromal cells from a different patient, of intact male mice. RESULTS: On average, mice developed tumours (primary and metastatic) four months following injection. Tumour incidence was greater from the CD44+/a2b1hi/CD133+ stem cell population despite injecting fewer than 500 cells. Differentiated phenotypes formed only rare tumours, even with an input of 10E6 cells. CONCLUSIONS: These results suggest that the cancer stem cell is likely to be the most crucial target in the treatment of prostate cancer, and a thorough understanding of its biology, particularly of how the cancer stem cell differs from the normal stem cell, might allow it to be targeted selectively and eliminated.

Eur Urol Suppl 2006;5:790

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TRANSFORMING GROWTH FACTOR STIMULATED CLONE 22 (TSC-22): POTENTIAL TUMOR SUPPRESSIVE ROLE IN PROSTATE CANCER AND NOVEL PROSTATE BASAL CELL MARKER Rentsch C.A.1 , Germann M.2 , Wetterwald A.2 , Schwaninger R.2 , Voller M.3 , Rotter V.4 , Oren M.4 , Schalken J.A.3 , Studer U.E.1 , Thalmann G.N.1 , Cecchini M.G.2 1 University Hospital of Bern, Department of Urology, Bern, Switzerland; 2 University Hospital of Bern, Urology Research Laboratory, Bern, Switzerland; 3 University Medical Center, Dept. of Exp. Urology, Nijmegen, The Netherlands; 4 Weizman Institute of Science, Department of Molecular Cell Biology, Rehovot, Israel

INTRODUCTION & OBJECTIVES: We have recently reported on TSC-22 as a basal cell marker of the human prostate and loss of TSC-22 protein expression in human prostate cancer (PC). In PC cell lines TSC-22 down-regulation corresponds to their tumorigenic and metastatic potential in vivo. There are two known human TSC-22 transcript variants (TV1 and 2). Studies in other cancers have focused on the short TV2, a downstream mediator of the tumor suppressive action of Transforming Growth Factor beta and peroxisome proliferator-activated receptor-gamma (PPARgamma) agonists. Here we investigated the expression and function of TSC-22 TVs in prostate cell lines. MATERIAL & METHODS: TSC-22 TV1 and TV2 were cloned in mammalian expression vectors which were used for transient transfection of prostate cell lines. A monoclonal anti-TSC-22 Ab (mAbTSC-22) was used for immuno-blotting and -histochemistry. PC cell lines (PC-3, LNCaP) and a human telomerase transformed prostate basal-cell cell line (Ep156T) were stimulated with TGFb, all-trans retinoic acid (ATRA), hepatocyte GF (HGF), epidermal GF (EGF) and the PPARgamma agonist rosiglitazone (Rz)or transiently transfected with TSC-22 specific siRNA (siTSC22). Cell growth was assessed by MTT-assays. RESULTS: mAbT22.1 recognises TV1 and TV2 150kD and 15kD specific bands in PC cell lines and 7 additional protein products in Ep156T. Of these a 40kD and 55kD product are absent in PC cell lines. Expression of TV1, TV2 and the 40kD product is affected by siTSC22. In PC-3 forced TV2 expression does not alter cell growth and silencing of TV2 expression does not change the growth inhibitory activity of TGFb and Rz. In Ep156T expression of the 40kD band only is affected by treatment with TGFb, HGF, EGF and ATRA and inversely correlates with the growth induced or inhibited by these compounds. CONCLUSIONS: TV1 and TV2 are expressed in basal cells and PC cells. TV2 does not have a tumor suppressive function in PC as reported in other cancers. The novel TSC-22 40kD protein product is absent in PC cell lines, its expression is modulated by GFs, and inversely correlates with in vitro growth of a basal cell line Ep156T. This suggests a potential tumour suppressive role for the TSC-22 40kD protein product in PC.

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INDUCTION OF PROSTATE CANCER CELL GROWTH, ANDROGENINDEPENDENCE AND BONE METASTASIS IN LNCAP CELLS BY HUMAN PROSTATE FIBROBLASTS OF DIFFERENT ZONAL ORIGIN Thalmann G.N.1 , Rhee H.2 , Sikes R.A.3 , Pathak S.4 , Zhau H.E.2 , Studer U.E.1 , Chung L.W.K.2 1 University Hospital of Bern, Department of Urology, Bern, Switzerland; 2 Emory University, Department of Urology, Atlanta, USA; 3 University of Delawara, Dept. of Biological Sciences, Delaware, USA; 4 University of Texas, Dept. of Cell Biology, Houston, USA

INTRODUCTION & OBJECTIVES: Clinically prostate cancer progression is characterized by the development of androgen-independence and the propensity to form bone metastases. We reported previously on the establishment of androgenindependent (AI) human prostate cancer cell lines derived from androgen-dependent (AD) LNCaP cells, which express prostate-specific antigen (PSA), are capable of growing in the castrated host and forming osteoblastic bone metastases. We evaluated the potential of human prostate fibroblasts (PF) derived from different zones of the prostate in inducing the growth of LNCaP cells and their progression toward androgen-independence. MATERIAL & METHODS: We isolated human PF from the peripheral (PZ), transitional (TZ) and central (CZ) zone of the prostate and established the AI and bone metastatic LNCaP sublines P4, P4-2, T4 and T4-2 using a previously established coinoculating procedure. We determined the biologic behaviorsof the parental and derivative LNCaP sublines in vivo and in vitro, as well as their molecular and cytogenetic characteristics. RESULTS: PF with defined zonal origin induce growth of LNCaP cells in vitro and in vivo. The in vitro growth of TZ-derived fibroblasts is more sensitive to dihydrotestosterone than PZ-derived fibroblasts. By contrast, PZ conditioned medium (CM) was more inductive than TZ CM on anchorage-independent LNCaP cell growth under soft agar conditions. The in vivo pattern of metastasis was from the primary to the lymph node and to the axial skeleton, with a predominant phenotype of osteoblastic reaction. Cytogenetic and biochemical characterizations of LNCaP sublines P4, P4-2, T4, and T4-2 demonstrate close similarities to human prostate cancer. These LNCaP sublines were found to grow faster under anchorage-dependent and -independent conditions and produced a substantially higher (3–10-fold) amount of basal steady-state concentrations of PSA in vitro than that of the parental LNCaP cells. CONCLUSIONS: Stromal-epithelial interaction of the cancer cell with the microenvironment plays a pivotal role in inducing permanent and inheritable changes through cellular interaction in vivo. Human prostate-derived fibroblasts from either the TZ or PZ modulate the growth, development of AI and metastatic progression of LNCaP cells when maintained as 3-D chimeric tumors in vivo.