AKT and AMPK activation after high-fat and high-glucose in vitro treatment of prostate epithelial cells.

Considering the increasing consumption of saturated fat and glucose in diets worldwide and its possible association to carcinogenesis, this investigation analysed the proliferation profile of nonmalignant human prostate epithelial cells after exposure to elevated levels of fat and glucose. PNT1A cells were cultured with palmitate (100 or 200 µM) and/or glucose (450 mg/dl) for 24 or 48 h. Treated cells were evaluated for viability test and cell proliferation (MTS assay). AKT and AMPK phosphorylation status were analysed by Western blotting. After 24 h of high-fat alone or associated with high-glucose treatment, there was an increase in AMPK and AKT activation associated to unchanged MTS-cell proliferation. Following 48 h of high-fat but not high-glucose alone, cells decreased AMPK activation and maintained elevated AKT levels. These data were associated to increased cell proliferation after further high-fat treatment. After longer high-fat exposure, MTS revealed that cells remained proliferating. High-glucose alone or associated to high-fat treatment was not able to increase cell proliferation and AKT activation. A high-fat medium containing 100 µM of palmitate stimulates proliferation in PNT1A cells by decreasing the activation of AMPK and increasing activation of AKT after longer exposure time. These findings improve the knowledge about the negative effect of high levels of this saturated fatty acid on proliferative disorders of prostate.

Guidance on the use of bisphosphonates in solid tumours: recommendations of an international expert panel.

Bisphosphonates (BP) prevent, reduce, and delay cancer-related skeletal complications in patients, and have substantially decreased the prevalence of such events since their introduction. Today, a broad range of BP with differences in potency, efficacy, dosing, and administration as well as approved indications is available. In addition, results of clinical trials investigating the efficacy of BP in cancer treatment-induced bone loss (CTIBL) have been recently published. The purpose of this paper is to review the current evidence on the use of BP in solid tumours and provide clinical recommendations. An interdisciplinary expert panel of clinical oncologists and of specialists in metabolic bone diseases assessed the widespread evidence and information on the efficacy of BP in the metastatic and nonmetastatic setting, as well as ongoing research on the adjuvant use of BP. Based on available evidence, the panel recommends amino-bisphosphonates for patients with metastatic bone disease from breast cancer and zoledronic acid for patients with other solid tumours as primary disease. Dosing of BP should follow approved indications with adjustments if necessary. While i.v. administration is most often preferable, oral administration (clodronate, IBA) may be considered for breast cancer patients who cannot or do not need to attend regular hospital care. Early-stage cancer patients at risk of developing CTIBL should be considered for preventative BP treatment. The strongest evidence in this setting is now available for ZOL. Overall, BP are well-tolerated, and most common adverse events are influenza-like syndrome, arthralgia, and when used orally, gastrointestinal symptoms. The dose of BP may need to be adapted to renal function and initial creatinine clearance calculation is mandatory according to the panel for use of any BP. Subsequent monitoring is recommended for ZOL and PAM, as described by the regulatory authority guidelines. Patients scheduled to receive BP (mainly every 3-4 weeks i.v.) should have a dental examination and be advised on appropriate measures for reducing the risk of jaw osteonecrosis. BP are well established as supportive therapy to reduce the frequency and severity of skeletal complications in patients with bone metastases from different cancers.

Protein C inhibitor in human body fluids. Seminal plasma is rich in inhibitor antigen deriving from cells throughout the male reproductive system.

An assay was developed for the measurement of human protein C inhibitor antigen (PCI) in blood plasma and other biological fluids. Both native PCI, modified inhibitor, and complexes of inhibitor with activated protein C or plasma kallikrein could be measured with the assay. Inhibitor antigen concentrations were found to be very high in seminal plasma (greater than 200 mg/liter), more than 40 times the concentration of PCI found in blood plasma. The inhibitor in seminal plasma was unable to form complexes with activated protein C. Gel filtration and immunoblotting findings indicated that the inhibitor in seminal plasma is present in a high molecular mass complex or cleaved to its modified form. As PCI antigen was absent from seminal plasma of patients with dysfunctional seminal vesicles, the seminal vesicle glands would appear to be the major source of seminal plasma PCI, a conclusion supported by immunohistochemical demonstration of the presence of PCI epitopes in the secretory epithelium of the seminal vesicles. Specific PCI immunoreactivity was also shown to be present in the testes, the epididymis glands, and the prostate, suggesting the inhibitor to have a complex or multiple function in the male reproductive system. Conclusive evidence of a local synthesis of PCI in the four male sex glands was provided by Northern blot analysis of RNA from these organs.

Octreotide scintigraphy and Chromogranin A do not predict clinical response in patients with octreotide acetate-treated hormone-refractory prostate cancer.

In this pilot study, the predictive value of Octreotide scintigraphy (Octreoscan) and/or Chromogranin-A (CgA) was investigated in patients with hormone-refractory prostate cancer treated with Octreotide acetate. In total, 20 patients with progressive disease and bone metastases entered the trial. At baseline Octreoscan, CgA, PSA, alkaline phosphates (ALP) and two self-administered questionnaires (EORTC QLQ C-30 (v3) and brief pain index) were performed and a diary of the pharmaceutical was started. The treatment consisted of Octreotide (Sandostatin LAR) acetate 30 mg intramuscular injection every month. The blood samples and questionnaires were repeated every month until 3 months. Clinical responder was defined as a patient with increased global health score more than 10 units and stable or decreased pain score without an increase in analgesic. In all, 17 patients were treated per protocol, and four were assessed as clinical responders. Six patients developed a reduction in ALP (median -26%, range -5 to -78%). All patients increased in PSA. At baseline, three patients had a negative Octreoscan and the patients with positive lesions, demonstrated uptake of low intensity. At baseline the CgA was elevated above the normal range in 15 of the patients, and during treatment five patients decreased their CgA to the normal range. Neither baseline Octreoscan nor CgA could identify the clinical reponders. A minority of patients improves their health-related quality of life. The decrease and normalization of CgA levels in five patients during therapy indicates therapeutic activity but Octreoscan and CgA could not identify clinical responders.

The androgen receptor status of neuroendocrine cells in human benign and malignant prostatic tissue.

Neuroendocrine (NE) cells containing neurosecretory granules, rich in various peptide hormones and biogenic amines, are components of the human prostate epithelium and prostatic adenocarcinomas. Neuroendocrine differentiation in prostatic adenocarcinomas has been associated with a poor prognosis and, following androgen withdrawal therapy, tumor cell populations have been observed to become enriched with NE cells. We assessed androgen receptor (AR) expression in NE cells in benign and malignant prostatic tissue using double-labeling immunocytochemistry with validated monoclonal antibodies to the AR and to chromogranin A (a generic NE marker). Neuroendocrine cells in benign and malignant prostatic tissue generally showed nuclear staining with AR. Some distinct AR-negative nuclei were observed in normal NE cells. In prostatic adenocarcinomas with extensive NE differentiation, a subpopulation of AR-negative NE cells was demonstrated. In conclusion, benign and malignant prostatic tissue contain both AR-positive and AR-negative NE cells that may have significance in regards to androgen-independent tumor growth and tumor progression.

Immunohistochemical localization of parathyroid hormone-related protein in human prostate cancer.

Parathyroid hormone-related protein (PTHrP) is produced by a variety of malignant tumors and has been implicated as a major cause of humoral hypercalcemia of malignancy. Expression of PTHrP in prostate cancer tissue was studied immunohistochemically using 33 radical prostatectomy specimens from patients with clinically localized carcinoma of the prostate. None of these patients demonstrated hypercalcemia prior to the surgery. Acetone-methyl benzoate-xylene-processed, paraffin-embedded tissues were stained with a validated mouse monoclonal antibody to an amino acid fragment, PTHrP(109-141), using the streptavidin-peroxidase enzyme conjugate method. All cases (33 of 33; 100%) studied demonstrated some degree of immunoreactivity throughout the cytoplasm of the tumor cells, but immunostaining was absent from inflammatory and stromal cells. The intensity of the staining appeared to directly correlate with increasing tumor grade. The widespread immunohistochemical localization of PTHrP in carcinoma of the prostate suggests that PTHrP may play some local role in the growth of transformed cells in the prostate. Furthermore, overexpression of PTHrP may be a possible marker to evaluate the malignant potential of carcinoma of the prostate.

Neuroendocrine cells in tumour growth of the prostate.

The prognostic significance of neuroendocrine differentiation in prostatic malignancy is controversial, but the results of recent studies with markers such as chromogranin A and neurone-specific enolase suggest that neuroendocrine differentiation, as reflected by increased tissue expression or blood concentrations of these neuroendocrine secretory products, is associated with a poor prognosis, tumour progression, and androgen independence. As all malignant neuroendocrine cells are devoid of androgen receptors and the expression of neuroendocrine cells is not suppressed by androgen ablation, clonal propagation of androgen receptor-negative neuroendocrine cells may have an important role in the development of androgen-independent prostatic carcinoma. This has significant implications for the treatment of prostate cancer, because several of the hormones that are secreted by neuroendocrine differentiated, malignant prostatic cells are potential candidates for use in drug treatment. A limited number of hormones have been tested in this context, in particular somatostatin, bombesin, and serotonin. As there is currently no successful treatment for differentiated prostate cancer, new therapeutic procedures and trials need to be developed to test drugs based on neuroendocrine hormones or their antagonists.

Androgen receptor immunostaining and its tissue distribution in formalin-fixed, paraffin-embedded sections after microwave treatment.

We used microwave (MW) oven heat treatment to unmask human androgen receptor (AR) immunostaining in formalin-fixed, paraffin-embedded tissue. Prostate tissue was used as an AR-positive control. Tissue sections were boiled in citrate buffer in a conventional MW oven for 30 min, followed by immunostaining with a validated murine monoclonal antibody (MAb), F39.4.1, raised against a peptide included in the N-terminal domain of the 100 KD human AR. AR immunostaining was localized to the nuclei of prostate secretory epithelial cells but was weak or absent in basal cells and of variable intensity in the stromal cells. Slides exposed to less than 10 min of MW heat treatment or none at all manifested no AR immunoreactivity. Tissue morphology was well preserved. Immunohistochemical determination of AR status in a wide variety of human tissues was consistent with that previously reported by others using frozen sections. MW heat treatment of tissue samples in an excellent method of localizing AR antigenicity, enabling immunohistochemical evaluation of AR status in formalin-fixed, paraffin-embedded material.

Immunohistochemical localization of parathyroid hormone-related protein in prostatic intraepithelial neoplasia.

Parathyroid hormone-related protein (PTHrP) is a regulatory protein hormone that has been associated with normal fetal growth and differentiation as well as fetal calcium regulation. Parathyroid hormone-related protein has been implicated in a variety of carcinomas as a major factor in the development of humoral hypercalcemia of malignancy and may also play a role as an autocrine growth factor. In a previous immunohistochemical study we found that all prostatic adenocarcinomas (CAP) express PTHrP. In the current study, we evaluated PTHrP in prostate intraepithelial neoplasia (PIN) in radical prostatectomy specimens. A validated mouse monoclonal antibody, 9H7, raised against fragment 109-141 of the carboxy-terminus of PTHrP was used for immunostaining. The results generally showed negative to weak staining of normal and hyperplastic tissue and strong staining in PIN. The staining intensity was further evaluated by computer based image analysis. The relative optical density in PIN (9.24 +/- 9.05) was significantly (P = .008) higher than that in normal gland (.00 +/- 3.6). These findings suggest that PTHrP may be involved in the pathogenesis of prostatic dysplasia, and its immunohistochemical evaluation may have diagnostic use in the evaluation of PIN.

Granins and prostate cancer.

OBJECTIVES: The importance of the expression of granin A (GRN-A, chromogranin-A) has become appreciated in the neuroendocrine differentiation of prostate cancer. We studied the expression of GRN-A in prostate cancer using serum immunoassay and tissue immunohistology procedures for this protein in order to define the clinical value of its measurements. METHODS: GRN-A production was measured by immunoassay in serum samples from patients with prostate cancer. Immunohistology procedures were used to assess GRN-A expression in paraffin-embedded prostate tissue samples. Serum and tumor findings were evaluated according to the patient's clinical status in studies by us and others. RESULTS: These studies demonstrated that GRN-A can serve as a prostate cancer serum and tumor marker with clinical value for both diagnosis and prognosis. Serum GRN-A was increased in early- and late-stage disease. Elevated serum GRN-A levels identified some patients with prostate cancer who did not have elevated serum prostate-specific antigen levels. In addition to their diagnostic value, increased serum GRN-A concentrations had prognostic value. CONCLUSIONS: Our own studies as well as those of others support the clinical potential of GRN-A as a marker for early, progressive, and recurrent prostate cancer. This demonstration of clinical utility notwithstanding, further studies are needed to clearly define the clinical value of GRN-A as a serum and tumor marker for this common cancer.

Expression of heme oxygenase-1 (HSP32) in human prostate: normal, hyperplastic, and tumor tissue distribution.

OBJECTIVES: Heme oxygenase isozymes, HO-1 and HO-2, are members of the stress/heat shock (HSP) family of proteins, with the known function of cleaving the heme molecule to biliverdin, iron, and carbon monoxide. The aim of this study was to examine the pattern of tissue expression of HO-1 in the human prostate under different states of proliferation and differentiation and to investigate whether the pattern differs between these states. METHODS: Presently, we have determined the pattern of tissue expression of the stress-inducible isozyme, HO-1 (HSP32), in human prostate under normal and pathologic conditions, by immunohistochemistry, using polyclonal antibodies, and have measured HO-1 and HO-2 mRNA levels in normal prostate and benign prostatic hyperplasia (BPH) by Northern blotting. The activity of prostate to catalyze heme degradation was also assessed. RESULTS: In normal and BPH tissue, columnar epithelial cells of acini and ducts and cells in stroma displayed HO-1 immunoreactivity; in all cells, perinuclear staining was prominent. In BPH tissue, however, a more intense staining of the epithelial cells occurred, with notable staining of the basal cells. In undifferentiated malignant tumors, intense HO-1 staining was manifest in nearly all tumor cells, and also in the epithelial lining of blood vessels. HO-1 in the prostate tissue was found catalytically active and oxidatively cleaved the heme molecule (Fe-protoporphyrin IX) to biliverdin. Northern blot analysis shows that two forms of HO are present in the human prostate. Compared with normal tissue, predominantly hyperplastic tissue demonstrates a pronounced increase in the approximately 1.8 kb mRNA that hybridizes to the rat HO-1 probe. The levels of two transcripts, approximately 1.3 and approximately 1.7 kb, that hybridize to the rat HO-2 probe are not increased in BPH tissue. CONCLUSIONS: The finding that HO-1 expression is increased in BPH and malignant prostate tissue is consistent with a role for this stress protein in the pathogenesis of BPH and prostate cancer; in the context of iron metabolism, an argument is made in support of this possibility.

Neuroendocrine differentiation in prostatic carcinoma during hormonal treatment.

OBJECTIVES: Neuroendocrine differentiation (NED) is a common feature in adenocarcinoma of the prostate. Several studies suggest that NED may have a major impact on cancer progression as neuroendocrine (NE) secretory products have been shown to possess growth stimulatory effects. NED has also been proposed to constitute part of the mechanism by which a prostate cancer cell progresses toward androgen independence as NE tumor cells have been demonstrated to be devoid of androgen receptor immunoreactivity. In this retrospective study, we evaluated NED status in prostate cancer specimens from patients undergoing androgen ablation therapy. METHODS: The degree of NED in transurethral resection of the prostate (TURP) samples from 53 patients with prostate cancer was investigated by immunocytochemistry using polyclonal rabbit immunoglobin G (IgG) against chromogranin A (CgA). Changes in NED with time were determined by a manual semiquantitative cell counting method. RESULTS: During androgen withdrawal therapy, 21 tumors (40%) displayed increased NED concomitant with histopathologic tumor progression, whereas 29 carcinomas (55%) showed no change in NED status. However, a majority of the histopathologically unchanged tumors displayed marked NED at the first TURP and an increase in NED was by definition not possible. In only 3 cases (5%) was a decrease in NED observed with time. CONCLUSIONS: Androgen ablation therapy may be a contributing factor to the increase in NED of prostatic adenocarcinoma with time, and our findings imply that androgen withdrawal therapy enhances the selection and progression of NED, androgen-independent tumor cells.

A DNA cytometric proliferation index improves the value of the DNA ploidy pattern as a prognosticating tool in patients with carcinoma of the prostate.

OBJECTIVES: A still controversial issue is whether the results of a cytometric assessment of the DNA distribution pattern of the nuclei of the neoplastic parenchymal cells of a prostatic adenocarcinoma has additional prognostic value to that of the stage and grade of the disease. To increase the accuracy of the DNA ploidy assessments. Image cytometry (ICM) has been used and combined with the determination of an ICM proliferation index (PI) to increase its value as an additional prognosticating tool. METHODS: We investigated 96 patients, followed up since diagnosis in 1980/1981 until death or, in 11 surviving patients, for an average of 14.5 years. Survival analysis was made by the conventional Kaplan-Meier method. Fine-needle aspiration biopsy was used as the major diagnostic tool. The neoplastic cell nuclei were classified as ICM DNA diploid, tetraploid, or aneuploid by means of the ploidy-establishing peak in the ICM DNA histograms, as well as the fraction of tumor cells in the S-phase. Scattered cells to the right of the ploidy-establishing peak, the S-phase fraction, and those in the G2M area of the ICM DNA histograms were counted as percent of the total number of tumor cells; this percentage was defined as the PI. Arbitrarily, tumors with a PI less than 5% were classified as having a low proliferation rate, those with a PI greater than 10% were considered highly proliferating, and those with a PI between 5% and 10% as carcinomas with an intermediate proliferation potency. RESULTS: By univariate analyses, clinical stage, cytodiagnostic grade, cytometric DNA ploidy pattern and PI all had significant prognostic value. By multivariate analyses, the PI was found to add prognostic information to that of the ICM DNA ploidy pattern variable, giving it an increase in its statistical P value from 0.002 to 0.0005. As a consequence, the combination of these two variables was found to give rise to three new patient groups with regards to their prognosis: DNA group I had tumors with a diploid ICM DNA pattern with a low PI; DNA group II had tumors with a diploid or tetraploid ICM DNA tumor cell nuclei pattern with an intermediate PI; and DNA group III had a diploid or tetraploid ICM DNA pattern with high PI and all tumors with an aneuploid pattern. By multivariate analysis, including tumor grade and clinical stage, these new DNA groups (P = 0.0004) and M stage disease (P = 0.0006) were the only significant prognostic variables. CONCLUSIONS: A DNA cytometric PI improves the prognosticating value of DNA ploidy. Patients with prostatic adenocarcinomas, classified as DNA group I, have a low risk of death from their neoplastic disease with deferred or hormonal treatment only.

Painful bone metastases in hormone-refractory prostate cancer: economic costs of strontium-89 and/or external radiotherapy.

OBJECTIVES: In a prospective randomized Canadian trial, addition of radionuclide strontium (89Sr) to external radiotherapy (ER) was found to prolong the time to further ER by 15 weeks (35 versus 20, P = 0.006) compared to ER alone in patients with hormone-refractory metastatic prostate cancer (HRMPC). The total direct lifetime costs within the Swedish health care system for the following two treatment strategies was estimated as follows: (a) ER initially and in the event of relapse and (b) ER + 89Sr initially and ER in the event of relapse. METHODS: Calculation of lifetime costs was based on the initial total treatment cost and the probability of future treatment costs. In a retrospective analysis, the average cost of a relapse treated with ER alone was calculated from the actual care consumption of 79 consecutive patients from the south of Sweden who received ER because of skeletal pain due to HRMPC. The costs related to ER included skeletal scintigraphy, ER, outpatient visits, inpatients days, and travel to the treatment center. When 89Sr was added, the cost also included the radionuclide and its administration. Costs in Swedish currency (SEK) were based on the regional tariff for 1993 (U.S. $1 = SEK 8.30). RESULTS: The initial cost for one relapse treated with ER alone was estimated to be SEK 31,011 (U.S. $3736) per patient resident within county (close to hospital) and SEK 48,585 (U.S. $5854) per patient resident out of county (far from hospital). The corresponding figure for initial addition of 89Sr to ER was SEK 43,426 (U.S. $5232) and 61,000 (U.S. $7349), respectively. However, comparison between estimated lifetime cost for the two treatment strategies indicated potential cost savings with initial addition of 89Sr to 3% SEK 2720 (U.S. $328) and 7% SEK 11,290 (U.S. $1360), respectively. CONCLUSIONS: Strontium-89 as initial supplement to ER for palliation of pain in HRMPC is beneficial both from the patient and lifetime health service costs perspectives.

Production of alpha-1-antichymotrypsin by PSA-containing cells of human prostate epithelium.

Prostate-specific antigen (PSA) is a chymotrypsin-like serine protease exclusively produced by the prostate epithelium, and abundant in seminal fluid. In serum, PSA is predominantly complexed to a liver-derived serine protease inhibitor, alpha-1-antichymotrypsin (ACT). A higher proportion of serum PSA is complexed to ACT in prostate cancer than in benign prostate hyperplasia. Since the molecular basis for this is unclear, we have investigated whether or not ACT may be produced in the prostate gland. Immunocytochemistry, using either monoclonal or polyclonal IgGs, demonstrated specific immunostaining for ACT in normal PSA-containing prostate epithelium. Production of ACT in the normal PSA-producing prostate epithelium was demonstrated by means of nonradioactive in situ hybridization using 30-mer anti-sense DNA probes for ACT and for PSA. The ACT and PSA coding transcripts, as detected by in situ hybridization, were distributed perinuclearly, in contrast to the specific immunostaining for ACT and PSA which was most intense in the apical portion of the secretory cells. The results strongly suggest local production and release of ACT by the normal prostate epithelium that may be important for interaction between PSA and ACT in extracellular compartments.

Relationship of neuroendocrine cells of prostate and serotonin to benign prostatic hyperplasia.

Neuroendocrine (NE) cells containing neurosecretory granules, rich in various peptide hormones and biogenic amines such as serotonin (5-HT), are components of the human prostate epithelium. The NE cells probably subserve a paracrine or local regulatory role in both prostatic growth and differentiation as well as the exocrine secretory process. Neuroendocrine cells may be involved in the etiology of benign prostatic hyperplasia (BPH). In this study the number of NE cells in areas of BPH was compared with normal tissue using 5-HT immunocytochemistry. In addition, using high-performance liquid chromatography with electrochemical detection (HPLC-ECD), tissue levels of 5-HT and its metabolite 5-hydroxy-indoleacetic acid (5-HIAA) were analyzed in prostatic tissue extracts including 25 cases of BPH and 16 cases of normal tissue verified by adjacent histologic sections. Compared with normal prostate our results demonstrated a marked decrease in 5-HT immunoreactive NE cells in the vast majority of larger hyperplastic nodules of BPH. These findings were corroborated by quantitative analysis where a significant reduction in the tissue 5-HT levels in BPH (0.539 +/- 0.09 SE) compared with normal (1.75 +/- 0.22 SE) (p < 0.05) was found. When smaller nodules of BPH were studied, abundant NE cells, equal or increased in number compared with those in adjacent normal prostatic tissue, were seen. The small apparently developing BPH nodules and ductal-like structures contained NE cells which may be growth foci near the periphery of some hyperplastic nodules. These findings particularly in small hyperplastic nodules suggest that NE cells and their products involved in controlling cell proliferation through a paracrine hormonal mechanism and may be involved in the pathogenesis of BPH. Serotonin (5-HT) and NE peptides may represent that elusive local "missing link" often alluded to in various theories relating to the development of early nodular hyperplasia in BPH.

Rapid exponential elimination of free prostate-specific antigen contrasts the slow, capacity-limited elimination of PSA complexed to alpha 1-antichymotrypsin from serum.

OBJECTIVES: To study the rates of elimination of total prostate-specific antigen (PSA-T), free PSA (PSA-F), and PSA complexed to alpha 1-antichymotrypsin (PSA-ACT) from blood after radical retropubic prostatectomy (RRP). METHODS: We obtained venous blood from 10 patients with prostate cancer who were undergoing RRP. We analyzed PSA-F and PSA-ACT and equimolar detection of both of these forms together (PSA-T) by using immunofluorometric assays. An attempt was made to fit the serum concentrations of PSA-F, PSA-ACT, and PSA-T for each patient to exponential curves by applying one- and two-compartment models for pharmacokinetic analysis. RESULTS: Manipulation of the prostate during RRP resulted in a 3- to 28-fold increase in PSA-F concentrations in serum. Removal of the prostate resulted in a rapid, biexponential elimination of PSA-F from serum, corresponding to a mean initial (alpha) half-life of 0.81 hours and a mean terminal (beta) half-life of 13.9 hours. Serum PSA-ACT concentrations decreased by 20% to 40% immediately after removal of the gland; the elimination after surgery was slow and nonexponential, corresponding to a mean rate of 0.8 ng/mL/day. The elimination of PSA-T reflects a combination of the elimination patterns for PSA-F and PSA-ACT. CONCLUSIONS: The main proportion of PSA-F is rapidly eliminated from serum, possibly by glomerular filtration. PSA-F released during surgery did not form complexes with ACT, as suggested by the lack of PSA-ACT elevation in serum. The size (approximately 90 kDa) and the extensive in vitro stability of the PSA-ACT complex prevents renal clearance. The nonexponential elimination of the PSA-ACT complex is evidence of a capacity-limited process (e.g., metabolic transformation).

Alpha 1-antichymotrypsin production in PSA-producing cells is common in prostate cancer but rare in benign prostatic hyperplasia.

OBJECTIVE: To investigate the distribution and production of alpha 1-antichymotrypsin (ACT) and prostate-specific antigen (PSA) in benign hyperplastic and malignant prostatic tissue, respectively. METHODS: Using monoclonal anti-ACT and anti-PSA IgGs for immunocytochemistry and alkaline phosphatase conjugated 30-mer oligodeoxynucleotide probes for nonradioactive in situ hybridization, tissue specimens were studied from 15 patients with benign prostatic hyperplasia after transurethral resection of the prostate (TURP) and from 9 patients with bladder cancer who underwent cystoprostatectomy. Cancer specimens were from 23 TURP patients and from ultrasound guided core biopsies in 14 patients. Prostate tumors were graded according to the Gleason system. RESULTS: We found no or only occasional small foci of immunostaining for ACT, and no ACT transcripts in the PSA-producing epithelium in areas with benign nodular hyperplasia. By contrast, a high proportion of cells expressed both ACT and PSA in prostate cancers with low Gleason score, as detected by immunocytochemistry and in situ hybridization. Poorly differentiated tumor cells manifested greater variation in immunostaining for both ACT and PSA. As compared to tumors of low Gleason score, high-score tumors less frequently manifested immunostaining for ACT than for PSA, and less frequently generated hybridization signals for both PSA and ACT transcripts. CONCLUSIONS: A significantly higher proportion of serum PSA has been reported to be complexed to ACT in patients with prostate cancer than in patients with benign prostatic hyperplasia. The presently reported lack of ACT production in PSA-containing BPH nodules may contribute to this by making conditions less optimal for complex formation between PSA and ACT. As opposed to this, production of both ACT and PSA in prostate cancers may enhance the complex formation between PSA and ACT.

Parathyroid hormone-related protein: a potential autocrine growth regulator in human prostate cancer cell lines.

OBJECTIVE: We recently demonstrated that parathyroid hormone-related protein (PTHrP) is widely expressed by human prostate cancer tissue, suggesting that PTHrP might be involved in the growth and development of prostate cancer. To study this further, the production of PTHrP and its biologic effect were investigated using human prostate cancer cell lines. METHODS: The cell lines used were one androgen-dependent cell line, LNCaP, and two androgen-independent cell lines, PC-3 and DU-145. PTHrP secreted by cancer cells was measured by radioimmunoassay. The effect of PTHrP on DNA synthesis in these cells was determined by thymidine incorporation assay. RESULTS: All cell lines secreted immunodetectable levels of PTHrP in the culture-conditioned media. PC-3 cells secreted significantly higher amounts than the other two cell lines. A synthetic peptide, PTHrP(1-34), stimulated thymidine uptake in PC-3 and DU-145 cells more than threefold the control under serum-free and steroid-free conditions, whereas LNCaP was not affected. However, in the presence of dihydrotestosterone, DNA synthesis of LNCaP cells was stimulated by PTHrP in a dose-dependent manner. Additionally, this PTHrP-induced DNA synthesis was completely neutralized by a validated mouse monoclonal antibody (8B12) raised against PTHrP(1-34). CONCLUSIONS: Our data suggest that PTHrP may play a significant role in the growth of prostate cancer by acting locally in an autocrine fashion.