Differences in phenotype and gene expression of prostate stromal cells from patients of varying ages and their influence on tumour formation by prostate epithelial cells

Prostate cancer (PCa) is an age-related disease, and the stromal microenvironment plays an important role in prostatic malignant progression. However, the differences in prostate stromal cells present in young and old tissue are still obscure. We established primary cultured stromal cells from normal prostatic peripheral zone (PZ) of donors of varying ages and found that cultured stromal cells from old donors (PZ-old) were more enlarged and polygonal than those from young donors (PZ-young). Furthermore, based on immunocytochemical and ultrastructural analysis, the components of stromal cells changed from a majority of fibroblasts to a mixture of fibroblasts and myofibroblasts with increasing donor age. Using a three-dimensional in vitro culture system, we found that PZ-old stromal cells could enhance the proliferation, migration and invasion of cocultured benign BPH-1 and PC-3 cells. Using an in vivo tissue recombination system, we also found that PZ-old stromal cells are more effective than PZ-young cells in promoting tumour formation by BPH-1 cells of high passage (>100) and PC-3 cells. To probe the possible mechanism of these effects, we performed cDNA microarray analysis and profiled 509 upregulated genes and 188 downregulated genes in PZ-old cells. Among the changed genes, we found genes coding for a subset of paracrine factors that are capable of influencing adjacent epithelial cells; these include hepatocyte growth factor (HGF), fibroblast growth factor 5 (FGF5), insulin-like growth factor 2 (IGF2), insulin-like growth factor-binding protein 4 (IGFBP4), IGFBP5 and matrix metallopeptidase 1 (MMP1). Changes in the expression of these genes were further confirmed by quantitative real-time polymerase chain reaction (PCR), Western blotting and enzyme-linked immunosorbent assays. Overall, our findings indicate that stromal cells from prostate PZ of old donors are more active than similar cells from young donors in promoting the malignant process of adjacent epithelial cells. This finding hints at a new potential strategy for the prevention of PCa.     

Androgen receptors expressed by prostatic stromal cells obtained from younger versus older males exhibit opposite roles in prostate cancer progression

Aging is a major risk factor for prostate cancer （PCa）, and prostatic stromal cells may also promote PCa progression. Accordingly, stromal cells do not equally promote PCa in older males and younger males. Therefore, it is also possible that the expression of androgen receptors （ARs） by prostatic stromal cells in older versus younger males plays different roles in PCa progression. Using a gene knockdown technique and coculture system, we found that the knockdown of the AR in prostatic stromal cells obtained from younger males could promote the invasiveness and metastasis of cocultured PC3/LNCaP cells in vitro. By contrast, the invasiveness and metastasis of LNCaP cells was inhibited when cocultured with prostatic stromal cells from older males that when AR expression was knocked down. Moreover, after targeting AR expression with small hairpin RNA （shRNA）, matrix metalloproteinase （MMP） expression in stromal cells was observed to increase in the younger group, but decreased or remained unchanged in the older group. One exception, however, was observed with MMP9. In vivo, after knocking down AR expression in prostatic stromal cells, the incidence of metastatic lymph nodes was observed to increase in the younger age group, but decreased in the older age group. Together, these data suggest that the AR in prostatic stromal cells played opposite roles in PCa metastasis for older versus younger males. Therefore, collectively, the function of the AR in prostatic stromal cells appears to change with age, and this may account for the increased incidence of PCa in older males.     

Human Prostate Fibroblasts Induce Growth and Confer Castration Resistance and Metastatic Potential in LNCaP Cells

Background

The tumor microenvironment is important for progressive and metastatic disease.

Objective

To study the hypothesis that prostate fibroblasts have differential ability to induce castration-resistant prostate cancer (PCa) and metastatic progression and whether this effect might vary depending on the zonal origin of the fibroblast.

Design, setting, and participants

Human prostate fibroblasts from the peripheral (PZ), transition (TZ) and central (CZ) zones of radical prostatectomy specimens (n = 13) were isolated and compared for their ability to promote androgen independence and metastatic progression in androgen-responsive PCa lymph node carcinoma of the prostate (LNCaP) cells in vivo.

Interventions

By coinoculating marginally tumorigenic LNCaP cells with PZ or TZ and by altering host hormonal milieu, a series of tumorigenic and metastatic LNCaP epithelial sublines–P4, P4-2 (derivatives from interaction with PZ), T4, and T4-2 (derivatives from interaction with TZ)–were established and characterized.

Measurements

In vivo and in vitro evaluation of induction of tumor growth and metastatic potential.

Results and limitations

1) LNCaP sublines were permanently altered in their cytogenetic and biologic profiles after cellular interaction with prostate stromal fibroblasts. LNCaP sublines grew faster under anchorage-dependent and -independent conditions, expressed 1–12-fold more prostate-specific antigen in vitro than LNCaP cells, and gained metastatic potential; 2) zonal differences of stromal fibroblasts in their ability to induce the growth and progression of LNCaP tumors as xenografts in mice may exist but need further analysis; 3) PZ-conditioned medium induced more anchorage-independent growth of LNCaP cells in vitro. TZ had a higher growth rate and were more sensitive to dihydrotestosterone.

Conclusions

We demonstrate that prostate fibroblasts have growth inductive potential on PCa cells and affect their subsequent progression to castration resistance and development of a metastatic phenotype.     

Patterns of spread of adenocarcinoma in the prostate as related to cancer volume

BACKGROUND: Peripheral zone (PZ) and transition zone (TZ) cancers of the prostate remain confined to their zone of origin under 4 cc volume, with progressive molding to TZ boundary. In PZ cancer, growth in perineural spaces over 4 cc volume directs cancer toward the base, around subcapsular nerve trunks, and often transcapsular. This tendency to stereotyped patterns of cancer spread in the prostate is investigated systematically here for the first time. METHODS: Cancers in 571 radical prostatectomy specimens were sorted by zone of origin and tumor volume. A traced map of each cancer at 3 mm transverse intervals was assessed for location, contour, selected linear measures and the "transverse (largest) reference plane". RESULTS: Spread along prostate capsule characterized all but the smallest PZ cancers and was most extensive transversely. By 4 cc volume, most PZ cancers' transverse reference plane filled one side of PZ. Above 4 cc, bilateral spread, TZ invasion, and nodularity progressively increased, but dominant growth was toward the base along nerves to the superior pedicle; here capsule penetration was most common. TZ cancers arose mainly in anterior-mid TZ, invading anterior fibromuscular stroma (AFM) while small. AFM was massively invaded in many large tumors. Larger TZ cancers (> 4 cc) invaded anterolateral PZ but seldom penetrated posterior PZ. CONCLUSIONS: Patterns and extent of spread of carcinoma in the prostate are stereotyped following a few principles regarding stromal interactions. Using these, sequential maps were presented of evolving prostate cancer contours at consecutive increasing volumes.     

The differential effects of prostate stromal cells derived from different zones on prostate cancer epithelial cells under the action of sex hormones

It is well known that prostate cancer (PCa) occurs predominantly in the peripheral zone (PZ), whereas benign prostatic hyperplasia (BPH) typically develops in the transition zone. To identify possible mechanisms underlying zonal differences, we compared the effects of prostate stromal cells derived from the peripheral zone (PZsc) and the transition zone (TZsc) on a PCa epithelial cell line (PC3) in the presence of sex hormones. First, we observed that androgen receptor (AR) mRNA was more highly expressed in PZsc than TZsc when the cells were treated with dihydrotestosterone (DHT) and β-oestradiol (E2) (P<0.05). By ELISA, we looked for differences in the secretion of peptide growth factors from PZsc and TZsc. We found that keratinocyte growth factor (KGF) secretion increased with increasing concentrations of DHT (P<0.01) and was higher in PZsc than TZsc. Under treatment with DHT plus E2, PZsc secreted more transforming growth factor-β1 (TGF-β1) than TZsc, but this pattern was reversed when the cells were treated with E2 only. With increasing concentrations of DHT, insulin-like growth factor-1 (IGF-1) secretion increased in PZsc but decreased in TZsc. To further characterize the effects of PZsc and TZsc on PC3 cells, we developed a coculture model and performed MTT assays, Western blot analysis and real-time RT-PCR. We found that PZsc promoted PC3 cell proliferation and progression better than TZsc, particularly when treated with 10 nmol l⁻¹ DHT plus 10 nmol l⁻¹ E2. In conclusion, our data suggest that PZsc may have a greater capacity to induce PCa development and progression than TZsc via growth factors regulated by sex hormones. These findings provide possible mechanisms underlying zonal differences in prostate diseases, which may aid the search for novel therapeutic targets for PCa.     

Elevation of dipeptidylpeptidase iv activities in the prostate peripheral zone and prostatic secretions of men with prostate cancer: possible prostate cancer disease marker

PURPOSE: Dipeptidylpeptidase IV (DPIV) is a multifunctional type II plasma membrane glycoprotein with serine-type exopeptidase activity that is secreted by the prostate and increased in prostate cancer. We determined whether changes in DPIV activities in prostatic tissue zones and expressed secretions were associated with the presence of cancer. MATERIALS AND METHODS: Expressed prostatic secretion (EPS), and biopsy of the transition (TZ) and peripheral (PZ) zones were collected from men undergoing ultrasound guided prostate biopsy. DPIV activities were measured by glypro-p-nitroanalide hydrolysis. RESULTS: DPIV activities were significantly higher in TZ than in PZ tissues in men with no evidence of malignancy. However, activities in EPS were negatively associated with TZ volume and positively associated with PZ volume. Mean and median DPIV activities in EPS from men with biopsy determined cancer were significantly higher than in men with no evidence of malignancy. DPIV activities in TZ and PZ biopsies were higher in men with cancer but most markedly in the PZ. CONCLUSIONS: These data indicate that secreted DPIV originates from the TZ and PZ. Increased DPIV activities in cancer are strongly associated with the PZ, which is the zone most commonly involved with cancer. Measuring DPIV levels in expressed EPS or post-digital rectal prostate examination urine may be useful for evaluating men for prostate cancer.     

Effects of age,sex steroids,and family relationships on volumes of prostate zones in men with and without prostate cancer

Benign prostatic hyperplasia (BPH) and prostate cancer commonly occur together. This suggests that common familial, hormonal, and environmental factors contribute to their development. In men at risk for the development of prostate cancer (at 40 men in 19 families) and aged-matched unrelated controls (n = 46), we have determined whether familial factors, age, and blood hormone concentrations are related to the transition zone (TZ), peripheral zone (PZ), or total volume of the prostate measured by transrectal ultrasound (TRUS). We determined that the influences of age, prostate cancer (n = 15), and familial status did not significantly affect the relationships reported. Therefore, data from all groups were combined for this study. TZ correlated positively with age (P = 0.003) after controlling for family status, but total prostate volume correlated insignificantly with age (P = 0.08). In addition, the ratio of TZ to PZ volumes also correlated significantly with age in the control group (r = 0.27, P = 0.014). Both TZ and PZ volumes correlated highly (r = 0.91, P < 0.0001, n = 86) with total volume. In addition, total volume correlated significantly (r = 0.71, P < 0.001) with the ratio of the TZ/PZ volumes, which also correlated significantly with each other (r = 0.61, P < 0.0001, n = 86). In contrast to the increase of TZ volume related to total prostate volume, PZ volume declined compared with total volume. Prostate volumes up to 50 ml are predominated by the PZ and above 50 ml by the TZ, which may compress and shrink the PZ. Both TZ and total prostate volume correlated positively with serum estrone concentrations (P = 0.04 and P = 0.003, respectively). These results suggest that the risk of prostate cancer does not contribute to generalized overgrowth of the prostate, including the TZ. However, estrogens and age strongly influence TZ but not PZ volume. Both PZ and TZ volumes rise together until the prostate exceeds 50 ml, when the growth of the TZ appears to exceed the PZ and then to compress it.     

The diverse and contrasting effects of using human prostate cancer cell lines to study androgen receptor roles in prostate cancer

The androgen receptor （AR） plays an important role in the development and progression of prostate cancer （PCa）. Androgen deprivation therapy is initially effective in blocking tumor growth, but it eventually leads to the hormonerefractory state. The detailed mechanisms of the conversion from androgen dependence to androgen independence remain unclear. Several PCa cell lines were established to study the role of AR in PCa, but the results were often inconsistent or contrasting in different cell lines, or in the same cell line grown under different conditions. The cellular and molecular alteration of epithelial cells and their microenvironments are complicated, and it is difficult to use a single cell line to address this important issue and also to study the pathophysiological effects of AR. In this paper, we summarize the different effects of AR on multiple cell lines and show the disadvantages of using a single human PCa cell line to study AR effects on PCa. We also discuss the advantages of widely used epithelium-stroma co-culture systems, xenograft mouse models, and genetically engineered PCa mouse models. The combination of in vitro cell line studies and in vivo mouse models might lead to more credible results and better strategies for the study of AR roles in PCa.     

Analysis of differences in clinicopathological features between prostate cancers located in the transition and peripheral zones

BACKGROUND: The objective of this study was to retrospectively characterize differences in the clinicopathological features of prostate cancer according to the zonal origin. METHODS: Among 185 consecutive patients who underwent radical prostatectomy without any neoadjuvant hormonal therapies, this study included 134 patients who were diagnosed as having either transition zone (TZ) or peripheral zone (PZ) cancer according to the following criteria: TZ or PZ cancers were considered when more than 70% of the cancer area was located in the TZ or PZ, respectively. The various clinicopathological features were then compared according to this classification. RESULTS: In this series, 27 patients were diagnosed as having TZ cancer, while the remaining 107 were diagnosed as having PZ cancer. The percent of positive biopsy cores in TZ cancers was significantly lower than that in PZ cancers; however, there were no significant differences in the anatomical location of positive cores between these two groups except for the middle of prostate where TZ cancer showed a significantly lower rate of positive biopsies than PZ cancer. The preoperative serum prostate-specific antigen (PSA) value in patients with TZ cancer was significantly higher than that in those with PZ cancer. Furthermore, tumor volume in TZ cancers was significantly greater than that in PZ cancers. However, there was no significant difference in biochemical recurrence-free survival between patients with TZ and PZ cancers. CONCLUSIONS: Despite the significantly high PSA value as well as great tumor volume compared with those of PZ cancers, TZ cancers had similar biochemical cure rates following radical prostatectomy, suggesting a less aggressive phenotype of TZ cancers than that of PZ cancers.     

Expression of bone morphogenetic protein messenger RNAs by normal rat and human prostate and prostate cancer cells

Human prostate cancer cells are known to produce several growth regulatory factors, including transforming growth factor β (TGFβ) and heparin-binding fibroblast growth factors (FGFs), which may play as-yet-undefined roles in prostate gland morphogenesis, as well as in prostate cancer cell behavior. Recently, a family of proteins in the extended TGFβ family, the bone morphogenetic proteins (BMPs), has been identified which stimulates bone formation in vivo, and in which, the proteins are likely involved in a variety of morphogenetic processes during embryogenesis. These powerful morphogenetic factors are capable of redirecting muscle mesenchyme cells to differentiate along the lines of bone tissue. We examined a number of well-characterized rat and human prostate cancer cell lines for the expression of BMP 2, 3, 4, and 6 messenger RNA. Poly(A + )-RNA was isolated from normal human and rat ventral prostate, from the rat prostate adenocarcinoma PAIII tumor and cultured cells derived from it, and from human prostate cancer cell lines PC-3, LNCaP, and DU-145. BMP mRNA levels were measured using BMP 2, 3, 4 and Vgr-1 (BMP 6) cDNA probes. Both normal and neoplastic prostate tissue expressed these BMP mRNAs, although the level of expression varied from tumor to tumor. Normal human prostate expressed BMP 4 mRNA predominantly, as did the human prostate cancers PC-3 and DU-145. PC-3 also expressed BMP 2 mRNA and BMP 3 mRNA in large amounts. Normal rat ventral prostate expressed all these BMP mRNAs, but the rat prostate adenocarcinoma PAIII expressed predominantly BMP 3 mRNA. The reason that different BMPs are expressed in varying amounts by these normal and neoplastic cells is unknown. However, if these BMPs are expressed in biologically active form, they could be responsible for important effects on normal prostate growth and morphogenesis, on neoplastic prostate cell behavior, and could even contribute to the capacity of prostatic cancer cells to stimulate new bone formation at metastatic tumor sites in bone. © 1994 Wiley-Liss, Inc.     

Does benign prostatic hyperplasia originate from the peripheral zone of the prostate? A preliminary study

OBJECTIVE: To compare the histological characteristics, cell proliferation, apoptosis and biological features in benign prostatic hyperplasia (BPH) in the peripheral (PZ) and transition zone (TZ) of the prostate. PATIENTS AND METHODS: Tissue from BPH in TZ and PZ was obtained from 68 patients undergoing transrectal ultrasonography-guided biopsy and used for both morphometric analysis and immunohistochemical studies. The epithelial, stromal and luminal composition of the tissue was determined using a computer-assisted method for quantitative morphometric analysis. Apoptosis was detected as the apoptotic index (AI) using the TdT dUTP nick-end labelling assay. Cell proliferation was determined as the proliferation index (PI) using Ki-67 immunostaining. The expression of epidermal growth factor receptor (EGFR), transforming growth factor beta1 (TGFbeta1), androgen receptor (AR) and bcl-2 were assessed immunohistochemically. RESULTS: There was no difference in the stroma/epithelium ratio between PZ and TZ hyperplastic nodules (P > 0.05). The mean AI in epithelium was almost identical to the corresponding PI. In stroma, no apoptotic cells were detectable. There was a significantly higher PI and AI in the glandular epithelial cells in PZ hyperplastic than in TZ hyperplastic nodules, but no difference in PI of the stromal cells between PZ and TZ hyperplastic nodules. There was significantly higher expression of TGFbeta1 and lower expression of EGFR and bcl-2 in PZ than TZ hyperplastic nodules (P < 0.05). There was no difference in AR expression between PZ and TZ hyperplastic nodules (P > 0.05). CONCLUSIONS: These results indicate that some hyperplastic nodules in PZ might originate from the PZ, and the formation of these nodules might be modulated in a different way from that in the TZ.     

不同年龄段前列腺外周带基质细胞差异基因表达的研究

目的:探讨不同年龄段前列腺外周带(PZ)基质细胞基因表达的差异。方法:原代培养前列腺PZ基质细胞按不同年龄段分为23～32岁为PZ-young组和56～75岁为PZ-old组,利用Affymetrix基因表达谱芯片筛选不同年龄段PZ基质细胞间的差异基因,通过实时荧光聚合酶链反应(Q-PCR)和Western印迹进行验证。结果:老年组(PZ-old)与年轻组(PZ-young)PZ基质细胞的基因表达存在显著性差异。基于倍性变化比(Fold ChangeRatio)≥2或≤0.5(PZ-old vs PZ-young),筛选上调基因509个和下调基因188个;结合DiffGene Pathway和GeneOntology基因功能归类,筛选并初步验证一组对前列腺上皮细胞生长有重要影响的显著差异基因,包括HGF、IGF2、IGFBP5及MMP1等。结论:不同年龄段前列腺PZ基质细胞基因表达存在差异,老龄化的PZ基质细胞促进前列腺上皮细胞恶性表型进展的分子机制可能主要通过活性增强的旁分泌生长因子的调节。     

正常前列腺基质细胞抑制前列腺癌细胞系PC-3增殖的体外实验研究

目的 探讨前列腺癌发病的基质－上皮相互作用机制。方法 体外培养前列腺基质细胞和前列腺癌（Pca)细胞系PC－3。分别取已用于培养液作为另一种细胞的条件培养液,观察条件培养液对细胞增殖的影响。用双层软琼脂分析法混合培养前列腺基质细胞和PC－3细胞。用MTT法检测不同浓度TGFβ1对PC－3细胞增殖率的影响。用免疫组化SP法研究基质中平滑肌细胞的比例。用RT－PCR方法检测基质细胞TGFβ1的表达。结果 PC－3细胞的增殖在混合培养时受到抑制。混合培养3周PC－3细胞的增殖率对照组的41％（P＜0．01）。PC－3细胞的增殖在加入TGFβ1后受到抑制,随TGFβ浓度的增加,对PC－3细胞的抑制作用增强。随TGFβ1作用时间的延长,相同浓度的TGFβ1抑制效应更显著（P＜0．01）。前列腺基质细胞表达大量的TGFβ1。结论 前列腺基质细胞可以通过分泌TGFβ1抑制PC－3的增殖。前列腺癌的基质可能存在病变,使癌变的上皮逃脱基质的抑制作用。     

Prognostic significance of prostate cancer originating from the transition zone

PurposeTransition zone (TZ) cancers are reported to have better biochemical relapse-free survival (bRFS) after radical prostatectomy (RP) than cancers from the peripheral zone (PZ). To understand the influence of tumor location, we compared bRFS for TZ and PZ cancers stratified for risk using known clinical and pathological prognostic factors.Patients and MethodsThe surgical pathology and outcomes of 494 patients were reviewed. Cancers originating from the TZ and PZ were identified from step sectioning of surgical specimens and tumor mapping. Univariate and multivariate analyses of bRFS after RP were compared.ResultsTZ cancers were present in 89 (18%) patients. On univariate analysis, most factors predicted bRFS, although cancer location did not: 5-year bRFS was 85% for TZ vs. 77% for PZ (P = 0.12). However, on multivariate analysis, all factors except SV involvement were significant, including TZ cancer location (P = 0.04, HR = 1.88 [1.02–3.47]). Interestingly, TZ location was correlated with improved 5-year bRFS for cancers > 2 cc (81% for TZ vs. 65% for PZ, P = 0.017), for preop PSA >10 (80% for TZ vs. 59% for PZ, P = 0.027), and for PSAV > 2 (85% for TZ vs. 66% for PZ, P = 0.08). However, TZ cancers showed no difference in outcome for small volumes, low preop PSA, low PSAV, or high Gleason grade.ConclusionsTZ cancers that are large, with high preop PSA, low Gleason scores, and high PSAV show better outcomes than their PZ counterparts. However, high-grade cancer tumor location had no apparent influence on outcome. Tumor location could be considered in subsets for optimal prognostication.     

正常前列腺不同区带及癌组织来源原代基质细胞的生物学特性及其对前列腺癌细胞株C4-2B的作用

目的 比较正常前列腺外周带来源原代基质细胞(NPPF),移行带来源原代基质细胞(NPTF)及前列腺癌组织来源原代基质细胞(CAF)的生物学特性差异,以及它们对前列腺癌细胞株C4-2B的不同影响.方法 苏木素-伊红(HE)染色鉴定前列腺不同区带及癌组织的组织学特征差异;原代培养NPPF、NPTF、CAF,免疫细胞化学染色观察其波形蛋白(Vimentin)、平滑肌动蛋白(SMA)及前列腺特异性抗原(PSA)的表达,生长曲线比较其增殖能力,流式细胞仪检测比较其凋亡率,透射电镜观察比较其超微结构;建立不同来源原代基质细胞与C4-2B细胞株共培养系统,比较不同来源基质细胞对C4-2B细胞增殖(MTT)和凋亡(FCM)方面的影响.结果 NPPF、NPTF、CAF的生长、凋亡、超微结构及对C4-2B细胞的生物学影响存在明显差异,其生长速度依次递增,凋亡率分别为(9.25±2.24)%、(5.98±0.74)%、(2.63±0.96)%,透射电镜提示CAF蛋白质合成最旺盛;C4-2B细胞与基质细胞体外共培养后出现增殖加速,凋亡减少,MTT结果显示共培养2 d后吸光度分别0.540、0.471、0.632,共培养4 d后吸光度分别为0.554、0.488、0.670,P均<0.05;FCM结果显示与对照组(10.32±0.43)%比较,CAF对C4-2B细胞凋亡的抑制能力最强(3.36±0.17)%,其次是NPPF(5.97±0.70)%和NPTF(8.01±0.22)%,P<0.05.结论 NPPF、NPTF、CAF的生物学特性存在明显差异,这种差异可能是导致前列腺增生或前列腺癌发生发展的重要原因.     

Frequency and clinical significance of transition zone cancer in prostate cancer screening

Approximately 20% of prostate cancers originate in the transition zone (TZ). Although transrectal ultrasound (TRUS) and systematic biopsies have improved peripheral zone (PZ) cancer diagnosis, additional biopsies directed into the TZ may further improve cancer detection. To evaluate the frequency and clinical significance of TZ cancers, we added two TZ biopsies to the routinely performed sextant biopsies. Three hundred forty patients (aged 45–75) from our prostate-specific antigen (PSA) screening study (21,078 volunteers) with negative rectal examination findings underwent systematic and TZ biopsies with three-dimensional ultrasound equipment. All patients had elevated PSA levels according to age-specific reference ranges. Ninety-eight of 340 men (28.5%) had biopsies positive for cancer. Of these 98 cancers, 28 (28%) originated in the TZ only and 5 (5%) were located in the TZ as well as the PZ. Eight men showed TZ abnormalities on ultrasound images, of whom four had biopsies positive for TZ cancer. The TZ cancers detected were pathologically significant in 96% (27 of 28). Seventy-one percent (20 of 28) of pathologically staged cancers were found to be organ confined and all combined TZ and PZ cancers were advanced tumors. We conclude that TZ biopsies enhance the cancer detection rate in prostate cancer screening and should therefore be added to the routinely done sextant biopsies in men with PSA elevation and normal digital rectal examination findings. Prostate 30:130–135, 1997. © 1997 Wiley-Liss, Inc.     

A comparison of the biological features between prostate cancers arising in the transition and peripheral zones

OBJECTIVES: To investigate differences in the biological features of prostate cancer according to the zonal origin. PATIENTS AND METHODS: Among 172 consecutive patients who had a radical prostatectomy (RP), the study included 124 diagnosed as having either transition zone (TZ) or peripheral zone (PZ) cancer, defined according to whether there was > 70% of the cancer area in the TZ or PZ, respectively. The clinicopathological features were then compared between these groups. In addition, the RP specimens were stained immunohistochemically with antibodies to Ki-67, Bcl-2, matrix metalloproteinase-2 (MMP-2), MMP-9 and vascular endothelial growth factor (VEGF). RESULTS: Twenty-four patients were diagnosed as having TZ cancer and the remaining 100 as having PZ cancer. Prostate specific antigen (PSA) values in patients with TZ cancer were significantly higher than in those with PZ cancer. Tumour volume in TZ cancer was significantly greater than that in PZ cancer, but there was no significant difference in biochemical recurrence-free survival between the groups. Immunohistochemistry showed that despite there being no differences in Bcl-2 and VEGF expression between TZ and PZ cancers, there was significantly greater expression of Ki-67, MMP-2 and MMP-9 in PZ than TZ cancers. CONCLUSIONS: Despite there being no significant difference in biochemical recurrence-free survival after RP between patients with TZ and PZ cancers, there was less cell proliferation and biomarker levels related to invasive potential in TZ than in PZ cancers.     

High expression of PSM-E correlated with tumor grade in prostate cancer: a new alternatively spliced variant of prostate-specific membrane antigen

BACKGROUND: Prostate-specific membrane antigen (PSMA) overexpressed in prostate cancer (PCa) has been targeted for therapy and diagnosis of PCa. In the current study, PSMA cDNA was cloned from PCa tissue by RT-PCR. After sequencing, a new spliced variant of PSMA (PSM-E) was discovered and its specificity in PCa was evaluated. METHODS: PSM-E and PSMA mRNA were measured in LNCaP, PC-3 and prostate or nonprostatic malignancies. Following transfection of PC-3 with PSM-E cDNA in the pcDNA3.0 vector, PSM-E expression was measured by immunofluorescence and Western-blot. PSM-E and PSMA mRNA levels were quantified by a real-time PCR assay in normal prostate (n = 7), benign prostatic hyperplasia (BPH) (n = 22) and PCa (n = 41). The correlation between their levels and tumor grade was analyzed. RESULTS: PSM-E cDNA is identical to PSMA except for a 97-nucleotide region and a 93-nucleotide region. PSM-E and PSMA mRNA were detected in PCa and LNCaP, not in PC-3; PSMA could be detected in some nonprostatic tumors whereas PSM-E not. The expression of PSM-E protein was detected in transfected cells. Significant difference of PSM-E mRNA levels was observed among normal prostate, BPH and PCa (P < 0.001), and PSM-E levels increased with increasing Gleason score (r = 0.514, P < 0.001). PSMA mRNA levels were higher in BPH and PCa than in normal prostate (P < 0.001), but no difference between BPH and PCa, no significant correlation was observed between PSMA levels and Gleason score (r = 0.229, P = 0.057). CONCLUSIONS: PSM-E may be a potential prognostic indicator for PCa progression and may be a new target antigen for therapy of PCa.     

Inhibition of prostatic epithelial cell proliferation by a factor secreted specifically by prostatic stromal cells

Stromal cells from the prostate were recently shown to inhibit clonal growth of the prostatic carcinoma cell lines PC-3 (hormone-independent) and LNCaP (hormone-sensitive) in coculture. Our study revealed that stromal cell-conditioned medium strongly inhibited proliferation of PC-3 and LNCaP cells when grown in monolayer culture. Antiproliferative activity was found to be reversible, and was produced specifically by prostatic stromal cells and not by stromal cells derived from skin, foreskin, uterus, kidney, and Wilms' tumor. Inhibition was not species-specific, since the cell lines AT-2.1 and MATLyLu, derived from the Dunning rat prostate tumor, were also sensitive. No inhibition, however, occurred on breast and renal carcinoma cell lines, suggesting a prostate-specific action. The putative inhibiting factor(s) could be concentrated and partially purified by ammonium sulfate precipitation. The possible role in stromal control of epithelial cell proliferation is discussed.