Clusterin as a possible predictor for biochemical recurrence of prostate cancer following radical prostatectomy with intermediate Gleason scores: a preliminary report

Disease recurrence following radical prostatectomy is a major concern in prostate cancer patients. Gleason scores are useful in predicting recurrence. Low Gleason scores are usually associated with long disease-free intervals, while high Gleason scores are suggestive of early recurrence. However, prediction of recurrence has been difficult with intermediate Gleason scores. Clusterin is a ubiquitous secretory sulfated glycoprotein. It is also an antiapoptotic mediator in prostate cancer. The objective of the present study is to determine if clusterin can serve as a predictive biomarker for recurrence of prostate cancer with intermediate Gleason scores in patients following radical prostatectomy. Prostatic specimens with Gleason score of 6 (3+3) or 7 (3+4) were obtained from the archival bank. Three groups of specimens were investigated. The first group was from nine patients who developed recurrent disease according to a persistent rise of serum PSA within 3 years following radical prostatectomy. Those in the second group and the third group were from patients who showed no evidence of disease recurrence for at least 5 y (11 patients) and 10 y (eight patients), respectively following the surgery. Histological sections were subjected to immunohistochemical staining using a monoclonal antibody specific for clusterin. The staining intensity was scored as 0, 1, 2, and 3, with 0 being no staining, 1 showing less than 25% positive staining, 2 being 25-50% positive, and 3 showing greater than 75% positive staining. One-way ANOVA with Bonferroni correction was used for statistical analysis. Evaluation of the scores of clusterin staining was carried out according to four specific areas in each specimen. They were (a) benign epithelial cells, (b) malignant epithelial cells (cancer epithelia), (c) stromal cells surrounding benign cells, and (d) stromal cells surrounding malignant cells (cancer stroma). Staining score in prostatic epithelial cells, benign as well as malignant, showed no significant relationship among the three patient groups. However, when staining scores in stromal cells were compared, there was a significant difference between patients with recurrent disease and those showed no evidence of disease recurrence for at least 10 y. Results of this preliminary study support the important role of clusterin in the stromal component for prostate cancer progression. Clusterin immunostaining may be useful to aid the prediction of chance of disease recurrence in patients with Gleason score 6 or 7 prostate cancer following radical prostatectomy. Further studies with a large number of cases are warranted to verify this preliminary finding.

High fat diet increases the weight of rat ventral prostate

BACKGROUND

Understanding the mechanisms by which diet influences the prostate may eventually lead to novel approaches for preventing prostate cancer. The objective of this research is to examine the impact of dietary fat, vitamin D, and genistein on prostate weight, serum and intraprostatic androgen levels, and the expression of several androgen-response genes.

METHODS

Sprague-Dawley rats were fed, beginning at 21 days of age, for 1 or 3 months of experimental diets with high saturated fat (32.2% calories from fat), low saturated fat (3.6% calories from fat), genistein plus (20 mg/kg), genistein deficient, vitamin D surplus (4,000 U/kg), or vitamin D deficient. The body weight, food intake, the weights of the ventral prostate and dorsolateral prostate, and the levels of testosterone and dihydrotestosterone (DHT) in the serum and in the prostate were determined. The expression of androgen-response genes was characterized by Northern blot analysis.

RESULTS

The pilot experiments showed that high dietary fat appeared to consistently increase the weight of the ventral prostate, while vitamin D or genistein did not have a consistent effect on prostate weight. Further analysis confirmed that the ventral prostate is 15% (P < 0.001) heavier in the rat on a high fat diet as compared to a low fat diet. Dietary fat had no significant influence on the levels of serum and intraprostatic androgens and the expression of androgen-response genes.

CONCLUSIONS

Our results suggested that the ventral prostate weight of the rat is increased without affecting the androgen axis by feeding the animals with high fat diet beginning at 21 days of age. This observation is potentially important since epidemiological data suggest that saturated fat consumption is a major risk factor associated with prostate cancer incidence rate.

Apoptotic activity of doxazosin on prostate stroma in vitro is mediated through an autocrine expression of TGF-beta1

BACKGROUND

Doxazosin, an alpha-adrenergic antagonist, has been shown to induce apoptosis in prostatic stromal cells. The mechanism of this apoptotic action by Doxazosin remains undefined. The present study was carried out to demonstrate that the effect of Doxazosin on apoptosis of prostate stromal cells is mediated through an autocrine action of TGF-beta1.

METHODS

Primary cultures of human prostate cells were treated with varying concentrations of Doxazosin (0, 0.1, 1, 10, and 100 microM) for a period up to 3 days. At the end of the 3-day culture, cell numbers were counted. Apoptosis was assessed by a colorimetric terminal deoxyribonucleotide transferase labeling technique. TGF-beta1 was determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Compared to control cultures, cell numbers were significantly decreased as much as 68.4% in cultures treated with 10 microM of Doxazosin after 3 days incubation, while apoptosis increased by 64.7% in cultures treated with the same concentration of Doxazosin after 24 h. This decrease in cell number was reversed when antibody to TGF-beta1 was added to these cultures. Addition of TGF-beta1 (0, 1.0, and 10 ng/mL) to the cultures also decreased the cell numbers. Quantitation of TGF-beta1 in lysates of cells by ELISA revealed that the cells treated with Doxazosin (10 microM) produced as much as 62.5% more TGF-beta1 than in that of untreated cells.

CONCLUSIONS

These results demonstrate that the apoptotic effect of Doxazosin on human prostatic stromal cells is mediated through an autocrine production of TGF-beta1.

NCCN Practice Guidelines for Prostate Cancer

Systemic therapies for prostate cancer are likely to improve, and as they do, they will have enormous impact on the treatment of high-risk and locally advanced cancers. Further technical improvements in radiotherapy and alternative local modalities, such as cryoablation, are also likely, and will bring even more options for local control. It is certain these guidelines will continue to evolve.

Autocrine effect of DHT on FGF signaling and cell proliferation in LNCaP cells: role of heparin/heparan-degrading enzymes

BACKGROUND

LNCaP cells are androgen-sensitive human prostate cancer cells. They are characterized by a bell-shaped growth curve in response to increasing doses of dihydrotestosterone (DHT) in culture. At a low concentration of DHT (0.1 nM), these cells show an increase in proliferation, but their growth is arrested at a high concentration (100 nM) of DHT. Results of our previous study demonstrated that the inhibitory effect of DHT at a high concentration was mediated through the action of TGF-beta1. The objective of the present study was to elucidate the mechanism of the proliferative effect of DHT in LNCaP cells. METHODS AND RESULTS DHT stimulated LNCaP proliferation only when cells were cultured in the presence of serum. In serum-free cultures, the characteristic DHT-induced proliferation was not observed. The addition of neutralizing antibody against FGF-2 (basic fibroblast growth factor) was able to inhibit this DHT-induced proliferation. These results suggest that the proliferative effect of DHT was mediated through the action of FGF-2. However, results of the reverse transcriptase polymerase chain reaction indicated that LNCaP cells did not express FGF-2 message. As a result, the source of FGF-2 in these cultures must be the serum supplemented in the culture media. FGF-2 can bind to heparin sulfate chains within the extracellular matrix (ECM). In cultures treated with exogenous heparin, the proliferative effect of DHT was abolished. These results led to the development of the hypothesis that DHT treatment mediates the release of FGF-2 entrapped in the ECM through increased heparinase activity. The addition of heparinase to cultures of LNCaP cells, in the absence of DHT, was able to stimulate cell proliferation. Moreover, 0.1 nM DHT caused a significant increase in heparinase activity.

CONCLUSIONS

These results provide a possible mechanism for DHT action in LNCaP cells. In the absence of DHT, FGF-2 in culture was trapped in the extracellular matrix and was not available to interact with LNCaP cells. However, in the presence of 0.1 nM DHT, heparinase activity in the culture was elevated and, as a result, it liberated the trapped FGF-2 which, in turn, stimulated proliferation in LNCaP cells.

Cytotoxic sensitivity to tumor necrosis factor-alpha in PC3 and LNCaP prostatic cancer cells is regulated by extracellular levels of SGP-2 (clusterin)

BACKGROUND

SGP-2 is a ubiquitous secreted glycoprotein that prevents cellular apoptosis. This study was carried out to determine the extracellular action of SGP-2 in a model of tumor necrosis factor-alpha (TNF)-induced cytotoxicity using two human prostatic cancer lines, LNCaP and PC3. These two lines were selected because LNCaP cells are highly sensitive to the cytotoxic effect of TNF, while PC3 cells are resistant to TNF at 24 hr.

METHODS

Cells were cultured in the presence or absence of TNF (10 ng/ml). LNCaP cells were treated with varying concentrations of exogenous SGP-2, while PC3 cells were treated with antisera to SGP-2 with and without exogenous SGP-2. Following a 24-hr treatment, cultures were assessed by counting of cell number and by the trypan blue exclusion assay.

RESULTS

Western blot analysis of conditioned media revealed that PC3 secreted more SGP-2 than did LNCaP. The sensitivity to TNF in LNCaP cells was reduced by the addition of exogenous SGP-2. PC3 cells became sensitive to TNF when SGP-2 antibody was added to the culture. The effect of SGP-2 antibody on PC3 cells was reversed by the addition of exogenous SGP-2 to the culture.

CONCLUSIONS

These results suggest that SGP-2 can act as an extracellular mediator of anti-TNF-induced cytotoxicity.

Differential growth rates in stromal cultures of human prostate derived from patients of varying ages

BACKGROUND

This study was undertaken to attempt to characterize changes in in vitro growth rates and cellular phenotypes of human prostatic stroma associated with aging and/or development of benign prostatic hyperplasia (BPH).

METHODS

Prostate stromal cell strains were established from 12 tissue donors of varying age. Culture growth rate was determined by cell counts over a 6-day period. Cell phenotype was assessed by immunocytochemical staining for smooth muscle alpha-actin, smooth muscle myosin, and prolyl-4-hydroxylase.

RESULTS

Growth rates of prostate stromal strains in vitro varied. Stromal cells derived from aged males with BPH had significantly slower growth rates than cells from younger donors. A positive reaction for prolyl-4-hydroxylase, a mesenchymal cell marker, was present in all cell cultures regardless of donor age. Expression of smooth muscle-specific actin, a nonspecific smooth muscle cell marker, was present in 48-79% of prostate stromal cultures. Staining for smooth muscle myosin, a specific smooth muscle cell marker, was found to vary significantly with age. The percentage of smooth muscle myosin-positive cells derived from males aged 15, 45, 57, and 72 years were 0.70 +/- 0.14%, 2.12 +/- 0.30%, 4.20 +/- 0.89%, and 26.25 +/- 1.0%, respectively. The shape and size of actin- and/or myosin-positive stromal cells from a 72-year-old donor culture were also usually larger and polygonal in shape as compared to thin and elongated shapes in 15-year-old donor cultures. The shape of actin- and/or myosin-positive cells from a 45-year-old donor culture demonstrated both phenotypes.

CONCLUSIONS

These results suggest that in human prostate stromal cells cultured as described, the growth rate decreases, the percent of smooth muscle cells increases, and the cellular shape changes with increasing donor age and/or development of BPH.

Acute adrenal insufficiency following unilateral radical nephrectomy: a case report

Adrenal insufficiency following unilateral radical nephrectomy has not been previously described in medical literature. We present a 78-year-old male patient who experienced a difficult postoperative course with vague findings, and was ultimately diagnosed with acute adrenal insufficiency. Treatment with glucocorticoids and mineralocorticoids resulted in prompt control of the disease.

The pathogenesis of benign prostatic hyperplasia: a proposed hypothesis and critical evaluation

PURPOSE

We used expanding observations regarding effects of testicular epididymal plasma and nonandrogenic testis factor(s) (NATF) on prostate growth to propose and evaluate a hypothesis regarding the development of benign prostatic hyperplasia (BPH) in man.

MATERIALS AND METHODS

Current experimental data regarding the presence of NATF were reviewed. The potential for their exposure to the prostate by various routes was assessed. These observations were coupled with recognized anatomical, histological and epidemiological characteristics of BPH to construct a hypothesis regarding its pathogenesis.

RESULTS

In vivo observations in man, rats and dogs supported the systemic secretion of NATF. These factors probably are, at least in part, spermatogenesis related. In vitro evaluation of the effect of spermatocele derived testicular epididymal plasma on human prostate stromal cells indicated the presence of androgen independent and androgen synergistic stromal growth promoters. These factors have potential local and systemic access to the prostate. The almost ubiquitous development of a regional, histologically variegated nodular growth occurring in the prostate in the androgen diminished environment of the aging man is compatible with local as well as systemic exposure to an age associated secretion of NATF.

CONCLUSIONS

We propose that human BPH is an induced phenomenon that is usually initiated by local episodic exposure of periurethral prostate to mitogens secreted by the testis/epididymis. Once initiated, isolated or complex interacting proliferative stimuli from the testis/epididymis and a variety of other sources may achieve exposure to the prostate by several routes and simulate prostate growth.

Loss of expression of transforming growth factor-beta receptors is associated with poor prognosis in prostate cancer patients

Transforming growth factor beta (TGF-beta) is a potent inhibitor of proliferation in most cells and exerts its effects through an interaction with membrane receptors type I (TGF-betaRI) and type II (TGF-betaRII). Recently, we have demonstrated a correlation between the loss of expression of TGF-betaRI and TGF-betaRII and increasing Gleason score in archival human prostate cancer tissues. To evaluate the potential prognostic value of this observation, the present study investigated the expression of TGF-beta receptors in association with disease progression after the initial diagnosis in 52 archival human prostate cancer tissues. The expression of both TGF-betaRI and TGF-betaRII was correlated with the Gleason score, clinical tumor stage, 4-year survival rate, and serological recurrence rate after radical prostatectomy. Results revealed that there was a significant association between the Gleason score and the loss of expression of TGF-betaRI (P < 0.025) and TGF-betaRII (P < 0.01). However, only the loss of TGF-betaRI expression showed a statistically significant association with the clinical tumor stage (P < 0.05), 4-year survival rate (P < 0.05), and serological recurrence rate after radical prostatectomy (P < 0.025). Therefore, these data indicate that the loss of TGF-betaRI expression as measured by immunohistochemical staining may be a potential prognostic marker in prostate cancer patients.

Synergistic action of steroids and spermatocele fluid on in vitro proliferation of prostate stroma

PURPOSE

Our goal is to understand human prostate growth phenomena potentially important to BPH development and growth. The objective of the present study is to characterize in vitro prostate stromal proliferative factors in testis epididymal secretions.

MATERIALS AND METHODS

Human spermatocele fluids were used as a source of testicular epididymal plasma (STEP). Primary cultures of human prostate stromal cells were routinely grown in RPMI-1640 with 10% fetal bovine serum. During a 6-day experimental period, cells were cultured in RPMI-1640 in the absence of serum but supplemented with ITS. Whole STEP, ether stripped STEP, or heparin affinity column treated STEP was included in the culture medium with and without the addition of testosterone (T), dihydrotestosterone (DHT), or estradiol (E). Results of these treatments were assessed by cell counts. Antibodies against smooth muscle myosin heavy chain, smooth muscle alpha actin, and prolyl-4-hydroxylase were utilized in immunocytochemical characterization of cultured cells.

RESULTS

Whole STEP stimulated prostatic stromal cells derived from prostates of 15, 45, 70 and 72-year-old men. Treatment of STEP by ether stripping or heparin affinity column exposure did not result in a significant reduction in cell counts. With the exception of the 15-year-old specimen, addition of T or DHT to ether stripped STEP resulted in a significant increase in cell counts over that of ether stripped STEP treatment alone. Preliminary immunocytochemical evaluation indicated the presence of variable mixture of fibroblasts, myofibroblasts, and smooth muscle cells in these cultures.

CONCLUSIONS

These in vitro observations indicate that testis epididymal secretions contain androgen/STEP synergistic and androgen independent STEP factors promoting prostate stromal growth. These factors are not heparin binding. These observations are consistent with the concept that, in addition to the production of steroids, the testis produces non-androgenic factors that act in concert with, as well as independently of, androgen to stimulate prostatic growth.

Epidermal growth factor receptor activation in androgen-independent but not androgen-stimulated growth of human prostatic carcinoma cells

These studies were undertaken to assess the relative expression and autocrine activation of the epidermal growth factor receptor (EGFR) in normal and transformed prostatic epithelial cells and to determine whether EGFR activation plays a functional role in androgen-stimulated growth of prostate cancer cells in vitro. EGFR expression was determined by Western blot analysis and ELISA immunoassays. Immunoprecipitation of radiophosphorylated EGFR and evaluation of tyrosine phosphorylation was used to assess EGFR activation. The human androgen-independent prostate cancer cell lines PC3 and DU145 exhibited higher levels of EGFR expression and autocrine phosphorylation than normal human prostatic epithelial cells or the human androgen-responsive prostate cancer cell line LNCaP. PC3 and DU145 cells also showed higher levels of autonomous growth under serum-free defined conditions. Normal prostatic epithelial cells expressed EGFR but did not exhibit detectable levels of EGFR phosphorylation when cultured in the absence of exogenous EGF. Addition of EGF stimulated EGFR phosphorylation and induced proliferation of normal cells. LNCaP cells exhibited autocrine phosphorylation of EGFR but did not undergo significant proliferation when cultured in the absence of exogenous growth factors. A biphasic growth curve was observed when LNCaP cells were cultured with dihydrotestosterone (DHT). Maximum proliferation occurred at 1 nM DHT with regression of the growth response at DHT concentrations greater than 1 nM. However, neither EGFR expression nor phosphorylation was altered in LNCaP cells after androgen stimulation. In addition, DHT-stimulated growth of LNCaP cells was not inhibited by anti-EGFR. These studies show that autocrine activation of EGFR is a common feature of prostatic carcinoma cells in contrast to normal epithelial cells. However, EGFR activation does not appear to play a functional role in androgen-stimulated growth of LNCaP cells in vitro.

Intracellular levels of SGP-2 (Clusterin) correlate with tumor grade in prostate cancer

Our previous observations in LNCaP cells in vitro demonstrated an association between apoptotic cell death resistance and SGP-2 (Clusterin) overexpression. Accordingly, we hypothesized that high levels of cellular SGP-2 would aid in identifying biologically aggressive prostate cancer cells with unique survival advantages. To test this hypothesis, 40 archival radical prostatectomy and/or biopsy specimens of varying grades of prostate cancer were subjected to immunohistochemical SGP-2 staining. The resulting epithelial stains were quantified subjectively on a scale of 1-3 by four independent observers. Benign prostatic epithelial cells from young donors served as controls and showed a consistently weak staining intensity. In contrast, prostate cancer specimens showed varying degrees of staining intensity that correlated with a Gleason pattern (P = 0.006). This correlation supports the hypothesis that protection from apoptotic death may account, in part, for biologically aggressive tumor behavior.

Intrinsic and extrinsic factors controlling benign prostatic growth

This review will present a new concept on the etiology of the development of benign prostatic hyperplasia (BPH). Conventionally, two known etiological factors for the development of BPH have been aging and the presence of functional testes. Assignment of these two factors, although reasonable, has not been conducive to aid the research community to identify and isolate the patho-physiological agents that are directly responsible for the development of this disease. In the present review, we proposed a broadened concept of intrinsic and extrinsic factors for BPH. This concept offers identifiable research opportunities that will facilitate our quest in search for etiological agents for BPH. A brief description of various intrinsic and extrinsic factors and justifications for their selection will be discussed.

Comparative genomic hybridization and molecular cytogenetic characterization of two prostate cancer xenografts

Conventional cytogenetic analysis of two prostate tumor xenografts, LuCaP 23.1 and RP22090, was unsatisfactory for comprehensive genetic evaluation of the cell lines. Fluorescence in situ hybridization (FISH) for chromosome enumeration and comparative genomic hybridization (CGH) for numerical imbalance detection were performed and resulted in a more complete molecular cytogenetic characterization of these lines. Both xenografts were hypertriploid and had significant numerical imbalances. For example, LuCaP 23.1 had gain of all or part of chromosomes 3, 5, 6, 7, 8, 11, and 12 and the X chromosome and loss of all or part of chromosomes 2, 3 6, 8, 9, 10, 17, and 18. In RP22090, gain of all or part of chromosomes 5, 7, 8, 9, 10, 12, 14, and 15 was seen, whereas loss was seen for all or part of chromosomes 4, 6, 8, 15, 16, 17, 19, 20, and 22. Both xenografts reflect the high frequency of chromosomal changes seen in some late-stage prostate cancers, including many novel changes and some changes such as the loss of 8p and gain of 8q, which have been reported previously in primary and metastatic prostate cancers. Consistent changes in both lines, such as loss of chromosomes 6 and chromosome arm 8p and gain of chromosome 7 and chromosome arm 8q, may represent genetic events specific for prostate cancer development, but imbalances on other chromosomes such as 3, 9, 19, and 20, not frequently reported in prostate cancers, may reflect potentially important changes that should also be examined.

The differentiating agent phenylacetate increases prostate-specific antigen production by prostate cancer cells

The prostatic-specific antigen (PSA) is the tumor marker most widely relied upon for the monitoring of patients with prostate cancer. Recently, declines in the serum concentrations of PSA have been advocated as a surrogate marker of tumor response in clinical trials of investigational antitumor agents. We examined the hypothesis that this postulate may not apply to the evaluation of drugs such as phenylacetate, a differentiating agent endowed with mechanisms of action different from those of classic cytotoxic chemotherapy. Using human prostatic carcinoma LNCaP cells as a model, we show that phenylacetate induces PSA production despite inhibition of tumor cell proliferation. Incubation of LNCaP cultures with cytostatic doses of phenylacetate (3-10 mM) resulted in a three- to fourfold increase in PSA secretion per cell. This appears to result from upregulation of PSA gene expression, as indicated by elevated PSA mRNA steady-state levels in treated cells. The increase in PSA production per cell was confirmed in rats bearing subcutaneous LNCaP tumor implants that were treated systemically with phenylacetate. Further comparative studies indicate that upregulation of PSA is common to various differentiation inducers, including all-trans-retinoic acid, 1,25-dihydroxyvitamin D3, and butyrate but is not induced by other antitumor agents of clinical interest such as suramin. We conclude that declines in PSA may be treatment specific and that the exclusive use of this criterion as a marker of disease response may mislead the proper evaluation of differentiating agents in prostate cancer patients.

Loss of expression of transforming growth factor beta type I and type II receptors correlates with tumor grade in human prostate cancer tissues

Transforming growth factor beta1 (TGF-beta1) is a potential regulator of prostate cancer cell growth that signals through a heteromeric complex composed of type I and type II receptors. In the present study, an attempt was made to establish a correlation between expression of TGF-beta receptors and tumor grade in archival human prostate cancer tissues. To this end, immunohistochemical studies for TGF-beta receptors were carried out on 32 cases of human prostate cancer and 8 samples of benign human prostate. In both benign and malignant human prostate tissues, immunoreactivity for both type I and type II receptors was detected predominantly in epithelial cells. In addition, there was an inverse correlation between the loss of expression of TGF-beta1 type I and type II receptors and the tumor grade. Of the 32 prostate cancer cases screened, staining was completely absent in four samples for type II receptor (P < 0.05) and eight samples for type I receptor (P < 0.025). In contrast, all eight samples of benign prostate tissues investigated in this study showed strong staining for both type I and type II receptors. These results, taken together, indicate that human prostate cancer cells frequently have loss of expression of TGF-beta type I and/or type II receptors. Furthermore, these observations provide a potential mechanism for prostate cancer cells to escape the growth-inhibitory effect of TGF-beta.

Stromal cells of the human prostate: initial isolation and characterization

The present study was conducted to isolate and to characterize stromal cells from the human prostate and to study the effects of androgen and different growth factors in this model system. Benign prostatic hyperplasia (BPH) tissue samples were obtained from transurethral resection of the prostate (TURP). Tissue specimens were mechanically and enzymatically dissociated by treatment with DNAse and collagenase. Epithelial cells were separated from stromal cells by discontinuous Percoll gradient centrifugation. The stromal cells obtained were cultured in phenol red-free RPMI-1640 supplemented with 10% fetal bovine serum. Immunocytochemical analysis revealed that the stromal cell cultures were composed of both smooth muscle cells and fibroblasts. The short and broad, smooth muscle cells wee identified by using an antibody directed against alpha-smooth muscle actin. The thin and elongated fibroblasts stained positively for prolyl 4-hydroxylase. Smooth muscle cells were the predominant cell type in the present investigation. Typical cultures contained up to 99% of cells staining positively for alpha-smooth muscle actin. The prostate smooth muscle cultures were treated with dihydrotestosterone (DHT), bovine pituitary extract (BPE), basic fibroblast growth factor (bFGF) and transforming growth factor-beta (TGF-beta). When cells were cultured in serum free RPMI-1640 supplemented with ITS+ (insulin, transferrin, and selenious acid) no significant (P > 0.05) mitogenic effect in medium supplemented with ITS+. In the presence of 10% charcoal-stripped fetal bovine serum (cFBS) DHT, at a concentration of 0.1 nM, was able to cause a slight but significant (P < 0.05) mitogenic effect on BPH smooth muscle cells growth. Basic FGF was able to stimulate BPH smooth muscle cells in a concentration-dependent fashion. The combination of DHT and 0.1 ng/ml bFGF was able to increase the proliferation of prostate smooth muscle cells above either agents alone. Addition of BPE to serum free RPMI-1640 caused a significant (P < 0.05) stimulation of cell proliferation in a concentration-dependent fashion. Addition to TGF-beta to serum or BPE containing RPMI-1640 caused a significant (P < 0.05) inhibition to cell proliferation in a concentration-dependent fashion. TGF-beta was cytostatic to the benign prostatic smooth muscle cells only in the presence of media containing growth stimulating factors found in charcoal-stripped serum or in bovine pituitary extract. These results demonstrated that stromal fraction isolated from BPH specimens was composed of both fibroblasts and smooth muscle cells. These cells could be cultured and were able to respond to various growth stimulatory and inhibitory agents.

Prevention of cell death induced by tumor necrosis factor alpha in LNCaP cells by overexpression of sulfated glycoprotein-2 (clusterin)

Sulfated glycoprotein-2 (SGP-2) expression has been associated with programmed cell death in the prostate, but its exact role remains unclear. The present study was carried out in an attempt to establish the function of SGP-2 in programmed cell death using tumor necrosis factor (TNF) alpha-induced cytotoxicity in LNCaP cells as the model system. LNCaP is an androgen-sensitive, human prostatic cancer cell line that responds to TNF in culture by undergoing programmed cell death, as determined by the loss of cell number, failure to exclude trypan blue, detection of DNA fragmentation, and increased release of previously incorporated [3H]thymidine. Immunocytochemical staining for SGP-2 was weak but evident in LNCaP cells. Following treatment with TNF alpha, there was a time-dependent increase in SGP-2 staining, the intensity of which peaked at 2 h and declined thereafter. SGP-2 staining in LNCaP cells was undetectable prior to the onset of DNA fragmentation at 6 h of TNF treatment. This observation indicated that TNF-induced cell death in LNCaP cells was characterized by an initial transient elevation of SGP-2, followed by a period of SGP-2 depletion that preceded cell death. Transfection of LNCaP with a 21-base oligonucleotide antisense to SGP-2 resulted in a significant increase in cell death that was sequence specific and was accompanied by a reduction in SGP-2 biosynthesis. These findings supported the concept that SGP-2 depletion, rather than its expression, was associated with cell death. Finally, stable transfection and subsequent overexpression of SGP-2 in LNCaP cells resulted in resistance to the cytotoxic effect of TNF. These results have provided evidence to indicate that SGP-2 plays a role in the protection of TNF-induced cell death in LNCaP cells.

Etiology of benign prostatic hyperplasia

Benign Prostatic Hyperplasia (BPH) is the most common neoplastic condition that afflicts men, and it constitutes a major factor impacting the health of the American male. This article reviews voiding dysfunction and the role of aging, the testis, and androgen in the development of BPH. Emphasis is placed on new concepts in the basic aspects of BPH etiology as a result of recent investigations.

Regulation of proliferation and production of prostate-specific antigen in androgen-sensitive prostatic cancer cells, LNCaP, by dihydrotestosterone

LNCaP is an androgen-sensitive human prostatic cancer cell line. The effect of androgen on these cells is characterized by a bell-shaped growth response and a dose-dependent induction of prostate-specific antigen (PSA) production. The present study was carried out to gain further insight into the effect of androgen on LNCaP. Cells were cultured in phenol red-free RPMI-1640 supplemented with 10% charcoal-stripped fetal bovine serum, with concentrations of dihydrotestosterone (DHT) ranging from 0-10(-7) M, in a 4-day culture system. A bell-shaped growth response was reproduced with a peak level of cell count at 10(-10) M DHT. PSA secretion from these cells did not increase significantly until the DHT level in the medium reached 10(-9) M. A progressive increase in PSA secretion was observed at higher DHT concentrations accompanied with a progressive decline in cellular proliferation. The results of immunocytochemical analysis of PSA localization indicated that the proportion of cells with positive staining for PSA also increased with increasing concentrations of DHT. Analysis of androgen receptors, as determined by both immunocytochemistry and Western blot analysis, showed a decline in nuclear androgen receptor at low concentrations of DHT and an increase in the amount of receptor protein at high concentrations. These results indicated that the androgen-induced bell-shaped growth response in LNCaP cells represented the manifestation of two different cellular events in dose-related manner: cellular proliferation at low DHT concentrations and increased production of PSA at high DHT concentrations.

Management of distant solitary recurrence in the patient with renal cancer. Contralateral kidney and other sites

About 25% to 57% of patients with RCC exhibit overt evidence of metastatic disease at the time of initial presentation. These patients have an average survival of about 4 months, and only 10% of them survive 1 year. Metachronous metastatic disease may develop in approximately 50% of patients who have undergone a presumably curative radical nephrectomy. Seventy percent of these patients relapse within the first year and manifest a median survival of about 11 months. The incidence of solitary metastatic lesions in patients with RCC ranges from 1.6% to 3.6%. In reality, the vast majority of these patients have evidence of subclinical, multifocal, micrometastatic disease and ultimately succumb to metastatic RCC. However, a 5-year survival rate of 35% to 50% can be achieved in properly selected patients using aggressive surgical treatment as a major component of therapy. In large part, insightful patient selection is predicated upon an understanding of the unique biologic and clinical issues relevant to each organ site of involvement.

Effect of spermatocele fluid on growth of human prostatic cells in culture

The present study was carried out to investigate whether testicular fluid derived from a spermatocele contains substance(s) that promote the growth of human prostatic cells in culture. Human spermatocele fluid was centrifuged to sediment spermatozoa. The supernatant was then added to cultures of human prostatic stromal or epithelial cells that were isolated from surgical specimens of benign prostatic hyperplasia. Addition of spermatocele fluid in quantities of 1 microgram/ml of protein resulted in a significant increase in the number of both prostatic stromal and epithelial cells at the end of a 6-day culture period. Human serum at equivalent protein concentrations in the culture medium had no stimulatory effect. At least two separate growth-promoting factors were found in spermatocele fluid, one for stromal cells and one for epithelial cells. The mitogen for stromal cells was heat labile and persisted after treatment with activated charcoal. The factor for epithelial cells was heat stable but was removed by charcoal treatment. These observations are consistent with the concept that the human testis secretes nonandrogenic substances that can promote prostatic growth.

Effect of retinoic acid on the proliferation and secretory activity of androgen-responsive prostatic carcinoma cells

We studied the effect of retinoic acid on the growth and secretory activity of the androgen-responsive prostatic carcinoma cell line LNCaP. Our data showed that retinoic acid at 0.01 microM. stimulated the proliferation of LNCaP cells but inhibited their growth at 0.1 microM. under androgen-free conditions. In the presence of 0.1 nM. dihydrotestosterone (DHT), LNCaP cell proliferation was inhibited by 10 microM. retinoic acid but not by lower concentrations of retinoic acid. Retinoic acid reduced LNCaP cell growth at concentrations of 0.1 microM. in the presence of 10 nM. DHT. Retinoic acid (10 microM.) also reduced the growth response of LNCaP cells to epidermal growth factor and transforming growth factor alpha and potentiated the inhibitory effect of transforming growth factor beta. In additional studies, retinoic acid induced a dose-dependent increase in prostate specific antigen (PSA) secretion at concentrations of 0.1 to 1 microM. Dihydrotestosterone (10 nM.) also enhanced the secretion of PSA by LNCaP cells, and this effect was potentiated in a dose-dependent fashion by the addition of retinoic acid at 0.1-10 microM. Competitive binding studies showed that retinoic acid did not bind to androgen receptors. Overall, retinoic acid had a biphasic effect on LNCaP proliferation and promoted the secretion of PSA. The biphasic effect of retinoic acid on LNCaP growth should be considered in designing in vivo studies to determine the impact of retinoic acid on solid prostatic tumor growth. In addition, the ability of retinoic acid to increase PSA secretion may complicate the interpretation of serum PSA levels used for diagnostic and prognostic purposes.

In vivo and in vitro approaches to study metastasis in human prostatic cancer

Prostate cancer is the most common malignancy in American males and is second only to lung cancer as a cause of death in the United States. Clinically, radical prostatectomy offers a patient with locally contained disease an excellent chance for cure. For patients with metastatic disease, the current therapies are merely palliative. Understanding the biology of prostate cancer metastasis should facilitate the development of novel and effective therapeutic modalities. Crucial to this objective is the availability of human tumor systems in which the biology of metastasis can be studied. The present chapter will briefly assess various in vivo and in vitro approaches to study metastasis in human prostate cancer. Utilization of athymic nude mice has played an important role in maintaining human prostatic cancer cells as xenografts and has provided an opportunity to establish site-specific subpopulations of the parental cell lines for further characterization and investigation. At present, a few established cell lines have been useful for this purpose. Fresh tumor specimens, unfortunately, have shown limited ability to grow in nude mice. The recent development of novel approaches to permit the maintenance of freshly harvested prostate cancers has been encouraging. The use of reconstituted basement membrane (Matrigel) for co-injection with cancer cells into the subcutaneous tissues has supported growth of biologically indolent tumors. Another approach is to administer tumor cells orthotopically into the prostate of recipient nude mice. Bone marrow metastases in nude mice have been rare in the past. Recently, three approaches have been shown to be successful in accomplishing bony metastasis with PC-3 cells.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA profile of nephrogenic adenoma assessed by flow cytometry

Nephrogenic adenoma is a metaplastic condition which usually involves the bladder urothelium within the clinical setting of chronic inflammation. Its presentation/endoscopic appearance may mimic bladder cancer and a premalignant potential has been speculated. DNA flow cytometry performed on involved bladder tissue revealed a diploid phenotype exhibiting low proliferative activity. These findings are most suggestive of a benign process.

Growth of an androgen-sensitive human prostate cancer cell line, LNCaP, in nude mice

This study was undertaken to establish an androgen-sensitive model of human prostatic carcinoma in nude mice. The androgen-sensitive prostatic carcinoma cell line, LNCaP, was suspended in reconstituted basement membrane (Matrigel) and injected subcutaneously into nude mice. The LNCaP cell line was chosen for the study, because the cell line is androgen-sensitive and secretes prostate specific antigen (PSA) into culture media. Following injection of 1 x 10(6) LNCaP cells with 0.25 ml of Matrigel, 88% of mice exhibited palpable tumor burdens after 12 weeks of observation. In addition, significant levels of PSA were observed in the serum of LNCaP-bearing mice. Bilateral orchiectomy of mice resulted in tumor regression and stabilization of serum PSA levels, compared to testis-intact controls. A significant correlation of PSA to tumor volume and weight was observed. The castrate level of testosterone was confirmed by radioimmunoassay and was similar to testosterone levels in female nude mice. Matrigel allows for a conducive environment to propagate LNCaP cells in nude mice. Furthermore, the growth can be manipulated by castration, leading to involution of tumor and stabilization of serum PSA level. This in vivo model of hormone-sensitive human prostate cancer cell line will serve as a model for the study of prostate tumor biology and treatment.

Epidermal growth factor receptor monoclonal antibody inhibits constitutive receptor phosphorylation, reduces autonomous growth, and sensitizes androgen-independent prostatic carcinoma cells to tumor necrosis factor alpha

Results of recent studies indicate that cultured, androgen-independent prostatic carcinoma cells synthesize and secrete transforming growth factor alpha, which interacts with epidermal growth factor receptors (EGFRs) to promote autonomous growth. In the present study, we evaluated the expression and constitutive activation of EGFRs in normal prostatic epithelial cells and the androgen-independent prostatic carcinoma cell lines PC3 and DU145. Our studies showed that cultured normal epithelial cells and androgen-independent prostatic carcinoma cells actively synthesize and exhibit constitutive phosphorylation of the M(r) 170,000 EGFR. The addition of monoclonal anti-EGFR reduced receptor phosphorylation and significantly inhibited the proliferation of prostatic tumor cells. The observed reduction in EGFR phosphorylation could be partially attributed to an antibody-induced decrease in the expression of metabolically labeled EGFR. Results of further studies showed that anti-EGFR enhanced the sensitivity of PC3 cells to the cytotoxic and cytostatic effects of tumor necrosis factor alpha. These studies demonstrate that constitutive activation of EGFR in androgen-independent prostatic carcinoma plays a functional role in the regulation of cellular proliferation in vitro. In addition, the enhanced sensitivity of prostatic carcinoma cells to tumor necrosis factor alpha in the presence of anti-EGFR provides a rationale for the further investigation of combination therapy in the treatment of disseminated, androgen-independent disease.

Basic fibroblast growth factor: a potential mediator of stromal growth in the human prostate

Studies were undertaken, using isolated prostatic epithelial and stromal cells, to evaluate the role of basic fibroblast growth factor (bFGF) in the regulation of benign prostatic growth. bFGF was detected in lysates, but not the conditioned media, of cultured prostatic epithelial and stromal cells by Western immunoblotting and immunoprecipitation of metabolically labeled proteins. Immunofluorescence analysis of benign human prostate localized the majority of bFGF to the prostatic stroma. In addition, bFGF was a potent stimulator of stromal cell proliferation in vitro, but was not mitogenic to cultured epithelial cells. Further studies demonstrated bFGF receptors (Kd = 258 pM; 61,400 receptors/cell) on stromal cells, but not epithelial cells. Epithelial cell-conditioned medium was mitogenic for stromal cells, suggesting the presence of paracrine interactions. However, bFGF does not appear to be the mediator of this interaction, since the mitogenic effect of epithelial cell-conditioned medium on stromal cells was not significantly reduced by the addition of anti-bFGF. Additional studies showed that concentrated stromal cell-conditioned medium was not mitogenic to cultured stromal cells under serum-free defined conditions, indicating the lack of an external autocine mechanism. These studies demonstrate that bFGF is actively synthesized by isolated prostatic epithelial and stromal cells, but is largely not secreted. Prostatic stroma, but not epithelia, are responsive to the mitogenic effect of bFGF in vitro. However, because of the limited secretion of bFGF by prostatic cells, the mechanism(s) of bFGF-mediated regulation of stromal growth remains unclear.

Inhibitory effects of suramin on a human renal cell carcinoma line, causing nephrogenic hepatic dysfunction

A sarcomatoid renal cell carcinoma has been isolated from a patient with Stauffer's syndrome. The tumor, designated BA1119, has been established in tissue culture over 80 passages. Subcutaneous deposition of BA1119 in athymic mice induced splenomegaly and hepatic dysfunction which became fatal within four weeks without metastasis. Suramin is a synthetic polyanionic compound which is capable of altering the function of a number of biologic systems and inhibiting the activity of a variety of protein and growth factors. In this study we attempted to study the effect of suramin on growth of BA1119 in culture and in nude mice. Suramin, at 300 micrograms/ml., had a profound inhibitory effect on cell growth during a six-day culture period. Suramin given i.p. weekly to nude mice at clinically relevant doses (200 mg./kg.) caused significant shrinkage of subcapsular tumor deposits. Splenic hypertrophy secondary to BA1119-induced Stauffer's syndrome was inhibited by suramin. Synergistic effect with enhanced cytotoxicity on BA1119 cells was observed when suramin (100 micrograms/ml.) was used in combination with lymphokines, such as gamma interferon (500 units/ml.) and alpha tumor necrosis factor (300 ng./ml.). These results may suggest a therapeutic efficacy of suramin in renal cell carcinoma patients with Stauffer's syndrome.

Regulation of prostatic carcinoma cell proliferation and secretory activity by extracellular matrix and stromal secretions

Previous studies from our laboratory have shown that reconstituted basement membrane and stromal secretory products are important regulators of benign prostatic epithelial cell growth and differentiation. In the present study we evaluated the impact of extracellular matrix (ECM) and soluble stromal secretory products on the proliferation and secretory activity of the androgen-responsive prostatic carcinoma cell line LNCaP. In these studies, dihydrotestosterone (DHT) was a potent mitogen for LNCaP cells cultured on plastic or on type I collagen. The growth response to DHT was greatly attenuated when LNCaP cells were grown on prostatic stromal ECM. Cells grown on stromal ECM also exhibited clustered morphology compared to the monolayer growth observed on plastic and secreted elevated levels of prostate specific antigen (PSA) and prostatic acid phosphatase (PAP). These findings indicate that cultivation of LNCaP on stromal ECM will promote the expression of differentiated functions. In additional studies, stromal cell conditioned medium (SCM) significantly increased PSA/PAP secretion by LNCaP cells in the presence of 10 nM DHT. The enhancement of DHT-induced PSA/PAP secretion by SCM was most pronounced when LNCaP cells were grown on stromal ECM. SCM did not significantly alter LNCaP proliferation. These studies indicate that prostatic stromal ECM and soluble secretory products will promote differentiated function in cultured LNCaP cells. In addition, we show that DHT can act as either a growth or differentiation-promoting stimulus depending on the presence of stromal factors.

Interaction of epidermal growth factor and transforming growth factor beta in human prostatic epithelial cells in culture

The present study was conducted to study the interaction between epidermal growth factor (EGF) and transforming growth factor-beta (TGF-beta) in benign human prostatic epithelial cells in culture. Primary cultures of human prostatic epithelial cells were grown in complete WAJC, which consisted of WAJC-404 medium and, in addition to other defined additives, EGF and bovine pituitary extract (BPE). Incomplete WAJC contained the same composition except EGF and BPE were deleted. TGF-beta was added into media at concentrations of 0, 0.1, and 1.0 ng/ml. When cells were grown in complete WAJC, they proliferated rapidly. Cell proliferation was greatly suppressed when incomplete WAJC was used. Addition of TGF-beta to these cultures caused a significant reduction in the final cell number when either complete WAJC or incomplete WAJC was used. In additional experiments, cells were prelabeled with 3H-thymidine for 72 hr prior to treatment with TGF-beta. The percentage of radioactivity released into the medium at the end of a 6-day culture was used as an indication of the extent of cell death. Trypan blue exclusion test was also used to assess the extent of cell death. Addition of TGF-beta into complete WAJC did not significantly affect the extent of cell death beyond what was considered as the result of normal cellular turnover. Addition of TGF-beta into incomplete WAJC, however, caused a significant increase in the percent of cell death in the culture. These results demonstrated an interaction between EGF and TGF-beta in proliferation and cell death in human prostatic epithelia in culture. In the presence of EGF alone in the culture medium, prostatic epithelial cells were stimulated to proliferate. The rate of proliferation was greatly diminished when EGF was deleted from the medium or when TGF-beta was added in the presence of EGF. Finally, cell death was induced when TGF-beta was added into the medium in the absence of EGF.

Inhibition of prostatic tumor cell proliferation by suramin: alterations in TGF alpha-mediated autocrine growth regulation and cell cycle distribution

Suramin is a trypanocidal drug that has generated recent interest as an antineoplastic agent because of its ability to inhibit the binding of growth factors to their cell surface receptors. Our studies, and others, suggest that the androgen-independent human prostatic carcinoma cell lines PC3 and DU145 proliferate via autocrine growth mechanisms mediated by transforming growth factor alpha (TGFa) and its receptor, the epidermal growth factor (EGF) receptor. The present studies were designed to evaluate the ability of suramin to inhibit PC3 and DU145 proliferation by interfering with TGFa-mediated autocrine growth. Suramin induced a dose-dependent reduction of prostatic tumor cell proliferation which was reversed by removal of suramin from the culture medium. 3H-thymidine release studies showed that suramin had little direct cytotoxicity to either cell line. These findings suggest that the effects of suramin are mediated by cytostatic, rather than cytotoxic, mechanisms. Suramin also interfered with TGFa-mediated growth mechanisms. Specifically, suramin reduced the specific binding of TGFa to PC3 and DU145 cells. Additionally, the inhibitory effect of suramin on DU145 was reversed by cultivation of cells in the presence of excess TGFa. Further investigations revealed that suramin increased the percentage of cells in the S phase of the cell cycle for both cell lines. These studies show that the inhibitory effect of suramin on PC3 and DU145 cell growth is mediated, in part, by alteration of TGFa-mediated autocrine growth mechanisms and cell cycle kinetics.

Prostate-type gland in the epididymis

We confirmed the presence of a prostate-type gland in the epididymis of a 30-year-old white man by immunohistochemical analysis using prostate specific antigen and prostate specific acid phosphatase. We suggest possible histogenetic mechanisms for such previously undescribed morphological heterogeneity within this wolffian duct derivative.

Autonomous growth of androgen-independent human prostatic carcinoma cells: role of transforming growth factor alpha

The androgen-independent prostatic carcinoma cell line PC3 is known to exhibit autonomous growth in vitro and in vivo. The purpose of the present study was to investigate the role of transforming growth factor alpha (TGF-alpha) and its receptor, the epidermal growth factor (EGF) receptor, in the regulation of PC3 cell proliferation. Results showed that PC3 cells secrete factors into conditioned medium that are mitogenic for the less aggressive prostatic carcinoma lines DU145 and LNCaP. Gel filtration chromatography of PC3-conditioned medium revealed a major peak of mitogenic activity at a molecular weight of 5,000 to 10,000 which was inhibited by the addition of antibody to TGF-alpha. The synthesis and secretion of TGF-alpha by PC3 cells were further demonstrated by immunoblotting and radioimmunoassay. Radioreceptor analysis showed a single class (Kd 5.3 nM) of EGF receptors on PC3 cells. The presence of Mr 170,000 EGF receptors on PC3 cells was further demonstrated by immunoprecipitation of metabolically labeled proteins. TGF-alpha was effective in stimulating the growth of low-density, but not high-density, PC3 cultures. In addition, the proliferation of PC3 cells under serum-free defined conditions was inhibited by antibodies to TGF-alpha and/or the EGF receptor. These data indicate that TGF-alpha/EGF receptor interactions are partially responsible for autonomous growth of the PC3 cell line and may explain one mechanism of escape from androgen-dependent growth in human prostatic carcinoma.

Advanced prostatic carcinoma. Early versus late endocrine therapy

Since the landmark observations of Huggins and Hodges in 1941, androgen deprivation has been the mainstay of treatment for advanced-stage prostate cancer. Although early, poorly controlled studies suggested enhanced survival with hormonal therapy, this view fell into disfavor as a result of the observations of the first and second VACURG studies. Recently, there has been a proliferation of experimental and clinical data supporting early androgen deprivation, including a reanalysis of the VACURG data, which suggests a survival advantage for younger patients with stage D disease and high-grade tumors who undergo androgen-ablative therapy at the time of diagnosis. The risk-benefit analysis presented in this review is strongly supportive of early hormonal therapy. Finally, long-term survival of patients with metastatic prostate cancer will require the development of novel treatment strategies effective against androgen-resistant tumor cells and their use in concert with early androgen deprivation.

Differential expression of specific cytokeratin polypeptides in the basal and luminal epithelia of the human prostate

The purpose of the present study was to identify cytokeratin polypeptides that are specifically associated with the basal and luminal epithelia of the human prostate. This aim was accomplished by immunohistochemical and immunoblot analysis of human prostate using cytokeratin-specific monoclonal antibodies. In immunohistochemical studies, monoclonal anticytokeratin 8.12 exhibited immunoreactivity with the basal, but not luminal, epithelial cells of fetal, juvenile, normal adult, and hyperplastic prostate. The 8.12 antibody did not stain prostate cancer tissues. Epithelia of 30 and 36 week fetal prostate contained only basal cells whereas both luminal and basal cells were noted in 7 month and 1 year old juvenile prostate. This finding suggests a stem cell function for the prostatic basal cells. Immunoblot analysis of proteins separated by two-dimensional electrophoresis showed that cytokeratins 5 and 15 were basal-cell-specific cytokeratins that were absent from prostatic carcinoma while cytokeratins 8 and 18 appear to be luminal-cell-specific. These results indicate that antibodies to specific cytokeratin polypeptides can be used not only to differentiate between prostatic basal and luminal cells but also to study the biological processes of prostatic organogenesis and carcinogenesis.

Heterogeneity in plasminogen activator (PA) levels in human prostate cancer cell lines: increased PA activity correlates with biologically aggressive behavior

Plasminogen activators (PA), particularly the lower Mr urokinase (u-PA) type, have been associated with tumor cell invasion and metastasis. We have examined the expression of PA by two human prostate cancer cell lines (PC-3 and DU-145) using functional and immunologic techniques. The culture media and cell extracts of the more aggressive PC-3 cell line contained more than two-fold greater PA activity than the relatively indolent DU-145 cell line. Zymographic studies identified the PA expressed as u-PA. PC-3 cells expressed an additional lower molecular weight form of u-PA not noted in DU-145 cells. Heterogeneity in u-PA expression was shown by the fibrin lysis assay, immunohistochemistry, and dual parameter flow cytometry indicating the presence of phenotypically divergent cell populations. Increased u-PA expression may identify those tumor cells that possess aggressive biological potential.

Reconstituted basement membrane promotes morphological and functional differentiation of primary human prostatic epithelial cells

Prostatic epithelial cells undergo rapid proliferation and lose their ability to synthesize and secrete prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) under standard tissue culture conditions. Herein, we compared the morphology, growth, secretory activity, and intermediate filament expression of human prostatic epithelial cells cultured on either standard tissue culture plastic or reconstituted basement membrane. Epithelial cells grown on plastic exhibited a 10-fold increase in proliferation and a higher percentage of cells in the S-phase of the cell cycle compared to cells cultured on basement membrane. However, cells grown on basement membrane secreted markedly higher levels of PSA and PAP. The basement membrane-induced enhancement of secretory activity was potentiated by dihydrotestosterone (DHT) and prostate stromal cell conditioned medium. Morphological studies showed that cells plated on basement membrane formed organoid-like clusters and maintained several aspects of differentiated epithelium including abundant secretory vesicles, microvilli, and desmosomes with associated cytoskeletal elements. Cultivation of epithelial cells on basement membrane components also suppressed the expression of vimentin, a mesenchymal intermediate filament polypeptide. However, cytokeratin expression was abnormal in cells grown on either surface. These results indicate that the differentiated properties of prostatic epithelial cells are promoted by cultivation on reconstituted basement membrane in the presence of DHT and stromal cell conditioned medium.

Therapeutic efficacy of recombinant tumor necrosis factor alpha in an experimental model of human prostatic carcinoma

Prostatic carcinoma represents the second leading cause of cancer mortality in men and is responsible for over 25,000 deaths each year. Currently, no curative therapy is available for metastatic carcinoma of the prostate. The present studies were undertaken to assess the efficacy of recombinant tumor necrosis factor alpha (TNF) in the therapy of experimental prostatic carcinoma. TNF was cytotoxic to the prostate cancer cell lines PC3, DU145, and LNCAP but not benign prostatic epithelial and stromal cells in vitro. The sensitivity of the prostatic carcinoma lines to TNF-mediated cytotoxicity was enhanced by the presence of actinomycin D. Intravenous administration of TNF (50-100 micrograms/kg) to nude mice bearing subcutaneous PC3 tumors resulted in significant inhibition of primary tumor growth compared to control. TNF was also effective in reducing the growth of intraabdominal PC3 tumors induced by intrasplenic injection of PC3. Furthermore, the incidence of microscopic PC3 foci in the spleen, liver, lung, and diaphragm was diminished in mice receiving TNF therapy. These studies demonstrate the potential of TNF in the therapy of human prostatic carcinoma.

Elevated transferrin receptor content in human prostate cancer cell lines assessed in vitro and in vivo

Transferrin receptors (TfR) were measured in benign and malignant prostatic cells by performing Scatchard analysis following the administration of 125I-transferrin. Established human prostate cancer cell lines (PC-3 and DU-145) as well as biologically aggressive variants (PC-3 ASC and PC-3 DES) were shown to possess significant levels of high affinity TfR when assessed in vitro. In contrast, TfR content was negligible in cultured stromal cell fractions derived from human benign prostatic hyperplasia (BPH) specimens. Scatchard analysis was also performed on in vivo derived prostatic tissues: tumors resulting from the subcutaneous xenografting of PC-3 ASC cells into athymic, nude mice and fresh BPH surgical specimens. These tissues were dissociated and their stromal and epithelial components separated. TfR were only detected in the epithelial component of both malignant and benign epithelial cells. PC-3 ASC tumor cells exhibited TfR levels comparable to their in vitro expression and these levels were 10-fold greater than in the BPH cells. These findings suggest that elevated TfRs may serve as another useful marker of the transformed phenotype within human prostate tumor systems.

Differential cytokeratin expression in normal, hyperplastic and malignant epithelial cells from human prostate

Studies were undertaken to define the expression of cytokeratins in normal, hyperplastic and malignant epithelial cells from human prostate. Cytokeratin (CK) polypeptides, separated by two-dimensional electrophoresis, were identified by immunoblotting with CK-specific monoclonal antibodies. CK polypeptides 5, 7, 8, 15, 18 and 19 were identified in fresh normal and hyperplastic prostate. Expression of CK 15 has not been previously reported in human prostate. Analysis of central and peripheral zone tissues from human prostate did not reveal qualitative differences in CK expression between these areas. Epithelial cells harvested from fresh BPH tissue by percoll gradient centrifugation and propagated in vitro using selective culture techniques showed alterations in CK expression compared to intact human prostate. Specifically, CKs 6, 14, 16 and 17 were noted in cultured BPH epithelial cells but not fresh normal prostate or BPH tissue. Immunoblot analysis of the established prostate cancer cell lines PC3, DU145 and LNCAP showed expression of CKs 8 and 18 but not CKs 5, 7 and 15 which were observed in benign prostate. These studies further characterize CK expression in benign and malignant human prostate and provide insights which may be useful in differentiating normal, hyperplastic and malignant epithelial cells in the human prostate gland.

Plasminogen activators in human prostate cancer cell lines and tumors: correlation with the aggressive phenotype

The levels of several tumor associated proteases, including plasminogen activators (PA), are elevated in many malignant tumors compared to their benign tumor counterparts. Extracellular matrix degradation mediated by PA may facilitate tumor cell invasion and metastasis. To assess whether PA content correlates with the aggressive phenotype in prostate cancer, we studied these activators in the PC-3 human prostate cell line and PC-3CALN, an aggressive in vivo derived variant cell line. Enzymatic assays using H-D-val-leu-lys-pNA (S-2251) as substrate and peroxidase-anti-peroxidase immunohistochemical techniques were used. In an in vitro chemoinvasion assay, the PC-3CALN variant cell line demonstrated significantly greater invasive behavior than the unselected, parental PC-3 line. The activity of PA secreted by PC-3CALN cells was 3.5 times greater than that of PC-3 cells (p less than 0.01). PC-3 metastases obtained following intrasplenic injection of PC-3 cells had greater PA activities than the corresponding primary tumors. Immunohistochemical studies of PC-3 tumors demonstrated preferential localization of urokinase-type PA to areas of apparent tumor cell invasion. These data suggest a correlation between PA and the aggressive phenotype in this model of human prostate cancer. PA, in particular u-PA, may play a role in the migration and invasion of prostate cancer cells and provide a marker of the aggressive phenotype.

Two-dimensional protein profiles of cultured stromal and epithelial cells from hyperplastic human prostate

Studies were undertaken to compare and contrast the two-dimensional protein profiles of epithelial and stromal cells from hyperplastic human prostate to establish the protein composition of the two major cellular components of the prostate. Epithelial and stromal cells were isolated from human prostate obtained from patients undergoing open prostatectomy for benign prostatic hyperplasia (BPH). Proteins, isolated from the two cell populations and separated by two-dimensional (2D) electrophoresis, were analyzed by silver staining, fluorography of [35S]-methionine-labeled proteins, and immunoprotein blotting. Isolated prostatic epithelial cells, but not stromal cells, contained cytokeratin polypeptides 5, 6, 7, 8, 13, 14, 15, 16, 17, 18, and 19. Although vimentin could not be identified in silver stained 2D gels and fluorographs of cultured prostatic epithelial cells, a low level of immunoreactivity was noted following immunoblot analysis of epithelial cells proteins by the use of an anti-vimentin polyclonal. Vimentin was prominently expressed in cultured prostatic stromal cells and could be identified on silver stained 2D gels, fluorographs, and immunoblots of stroma-derived proteins. In addition, stromal marker proteins SM1, SM2, and SM3 were identified in 2D gels of stromal cells to distinguish them from epithelial cells. These studies demonstrate (1) the two-dimensional protein profile and cytokeratin polypeptide composition of cultured epithelial cells from hyperplastic human prostate and (2) the 2D protein profile of cultured prostatic stromal cells and identification of specific stromal marker proteins.

Carcinoma of the prostate. Hormonal therapy

A selective review of the literature regarding hormonal therapy for patients with carcinoma of the prostate is presented to assess the current status of the following: therapeutic advantages, disadvantages and risks of alternate approaches to hormonal therapy; observations to predict the magnitude and duration of response to therapy; indications for initiating hormone therapy; the short-term and long-term effects of therapy; and role of hormone therapy in patients with recurrent tumor activity after initial hormonal measures.

Mesenteric desmoid tumor presenting as an abdominal mass following salvage cystectomy for invasive bladder cancer

The development of an abdominal mass after radical extirpative surgery for cancer is ominous and most frequently represents a recurrence of the original cancer. We present an unusual case of a large mesenteric desmoid tumor that occurred 3 years after salvage cystectomy for invasive bladder cancer.

A rapid in vitro assay for quantitating the invasive potential of tumor cells

We have reconstituted a matrix of basement membrane onto a filter in a Boyden chamber and assessed the ability of various malignant and nonmalignant cells to penetrate through the coated filter. Cells from all the malignant cell lines tested were able to cross the matrix in 5-6 h, whereas human fibroblasts as well as mouse 3T3 and 10T1/2 cell lines, which are not tumorigenic, were not invasive. In addition, normal primary prostate epithelial cells and benign prostatic hyperplasia cells were not invasive when tested in this assay, whereas malignant prostate carcinoma cells were highly invasive. Parallel experiments with these prostatic cells using the intrasplenic assay for metastasis detection in the nude mouse confirmed the benign behavior of the former cells and the metastatic phenotype of the latter ones. These results suggest that this in vitro test allows the rapid and quantitative assessment of invasiveness and a means to screen for drugs which alter the invasive phenotype of tumor cells.