Biomedical subjects

A Hobisch

Publications and source records attributed to A Hobisch.

At least 37 records · Page 2Linked to original sources

PubMed2000

Immunohistochemical localization of interleukin-6 and its receptor in benign, premalignant and malignant prostate tissue.

Interleukin-6 (IL-6) is a pleiotropic cytokine that interacts with its receptor in prostate cells, thus regulating proliferative response and differentiation. It also activates the human androgen receptor in prostate cancer cell lines. In order to assess the significance of these findings in vivo, the expression of key elements of the IL-6 signalling pathway, IL-6 and its receptor, was investigated in tissue samples obtained on radical prostatectomy from prostate cancer patients. IL-6 immunohistochemistry was performed on 17 frozen prostate cancer specimens. IL-6 receptor immunostaining was evaluated in 21 paraffin-embedded prostate tumour specimens. In both groups, adjacent areas of high-grade prostatic intraepithelial neoplasia and benign tissue were also investigated. In benign prostatic epithelium, IL-6 was localized predominantly in basal cells, whereas in prostate cancer tissues more IL-6-positive glandular cells were identified. No IL-6 expression was detected in stromal cells on immunohistochemistry, although IL-6 protein was measured in the supernatants obtained from cultured stromal cells by ELISA. IL-6 receptor was expressed in benign prostatic tissue in both epithelial and stromal cells. Furthermore, IL-6 receptor expression was observed in all tumour specimens investigated and the majority of Gleason patterns analysed had more than 50% of cells showing a positive reaction. IL-6 and IL-6 receptor expression patterns in high-grade prostatic intraepithelial neoplasia lesions were similar to those observed in tumour tissues. Taken together, the results of the present study imply that there are paracrine and autocrine IL-6 loops in benign and neoplastic prostate.

Adenocarcinoma↗

PubMed2000

Androgen receptor--an update of mechanisms of action in prostate cancer.

Androgen receptor (AR), a key nuclear transcription factor in the prostate gland, is expressed in all histological types and stages of prostate cancer. The AR regulates proliferation of prostate cancer cells by stimulation of cyclin-dependent kinases. However, in some prostate tumors AR stimulates expression of cell cycle inhibitors, thus leading to down-regulation of cellular proliferation. Androgens, by activation of the AR, control differentiation of prostate cells and synthesis of neutral lipids. There are several mechanisms by which prostate cancer cells adapt to an environment with low androgen supply during endocrine therapy. The AR expression and activity increase in several cell lines that are used as an in vitro model for monitoring changes during long-term androgen ablation. Mutant ARs are of importance for monitoring the natural course of the disease and for determining the response to anti-androgens in metastatic lesions from prostatic carcinoma. In addition, AR activity is up-regulated by various stimulators of intracellular protein kinases. Current research efforts are focused on elucidation of function of AR coregulatory proteins, coactivators and corepressors. Their inappropriate expression and/or function might critically influence cellular events in advanced carcinoma of the prostate. It is hoped that information on these coregulatory proteins will serve as a basis for a more efficient pharmacological inhibition of the AR in advanced carcinoma of the prostate.

Animals↗

PubMed2000

Quality of life after cystectomy and orthotopic neobladder versus ileal conduit urinary diversion.

The impact of bladder removal and urinary diversion for patients' everyday life is largely unknown. The aims of this study were to compare subjective morbidity of ileal neobladder to the urethra versus ileal conduit urinary diversion and to elucidate its influence on quality of life. A total of 102 patients who underwent cystectomy due to a bladder malignancy were included in the study. In 69 patients (67.6%) an orthotopic neobladder and in 33 patients (32.4%) an ileal conduit was performed as urinary diversion. The compliance was 99% and mean follow-up was 37 months. All patients completed two retrospective quality of life questionnaires, namely the QLQ-C30 and a questionnaire developed at our institution to ask for urinary diversion specific items. The questioning and assessment was performed by non-urologists. The results obtained from the validated (QLQ-C30) and our own specially compiled questionnaire clearly demonstrate that patients with an orthotopic neobladder are more able to adapt to the new situation than patients with an ileal conduit. In addition, neobladder to the urethra improves the quality of life because it improves self-confidence, causes better rehabilitation as well as the restoration of leisure, professional, travelling, and social activities, and reduced risk of inadvertent loss of urine. For example, 92.8% of neobladder patients did not feel handicapped at all, and 87% did not feel sick or ill, in contrast to 51.5% and 66.7% of ileal conduit patients, respectively. Of the neobladder patients, 74.6% felt absolutely safe with the urinary diversion in contrast to 33.3% in the ileal conduit group. Only 1.5% of neobladder patients had wet clothes caused by urine leakage during the day, versus 48.5% of ileal conduit patients. Moreover, 97% of our neobladder patients would recommend the same urinary diversion to a friend suffering from the same disease, but only 36% of ileal conduit patients would do so. These results demonstrate that the quality of life is preserved to a higher degree after orthotopic neobladder than after ileal conduit urinary diversion.

Aged↗

PubMed2000

Laparoscopic retroperitoneal lymph node dissection.

INTRODUCTION: Retroperitoneal lymph node dissection (RPLND) is the most accurate method for evaluating the presence of retroperitoneal metastases from clinical Stage I nonseminomatous testicular tumors. We have introduced laparoscopy to reduce the morbidity of open RPLND, which is too high for a diagnostic procedure. As the next step, we replaced open surgery with the laparoscopic approach for Stage IIb tumors to remove residual tumor after chemotherapy. TECHNICAL CONSIDERATIONS: One prerequisite for laparoscopic RPLND is free access to the retroperitoneum, which can be achieved by wide dissection of the colon and duodenum. The borders of the dissection are the same as with open surgery, and complete dissection can be achieved. Bipolar coagulation and the harmonic scalpel have proved very helpful in achieving adequate hemostasis, a crucial point. Venous lesions can be sealed with fibrin glue. CONCLUSIONS: Laparoscopic RPLND is superior to open surgery with regard to morbidity and complication rates, and operative times are equal once enough experience has been collected. The diagnostic accuracy is the same for both methods, and tumor control is not compromised by the laparoscopic approach. The only drawback of laparoscopy is the long and steep learning curve.

Humans↗

PubMed2000

Androgen receptor protein is down-regulated by basic fibroblast growth factor in prostate cancer cells.

Interactions between polypeptide growth factors and the androgen receptor (AR) are important for regulation of cellular events in carcinoma of the prostate. Basic fibroblast growth factor (bFGF), the prototype of heparin-binding growth factors, and the AR are commonly expressed in prostate cancer. bFGF diminished prostate-specific antigen protein in the supernatants of androgen-stimulated human prostate cancer cells LNCaP by 80%. In the present study, we asked whether the bFGF effect on prostate-specific antigen is preceded by action on AR expression. LNCaP cells were treated with bFGF and AR protein expression was determined by immunoblotting and ligand binding assay. bFGF down-regulated AR protein in a dose-dependent manner showing a maximal effect at 50 ng ml(-1) both in the presence or absence of dihydrotestosterone. Down-regulation of AR protein expression occurred already after 8 h of bFGF treatment and a maximal inhibition was observed 24 h after addition of bFGF to culture media. As AR expression can be reduced by an increase in intracellular calcium levels, we investigated whether the bFGF effect on AR protein is mediated by this mechanism. Calcium release from intracellular stores and store-operated calcium influx after treatment with either bFGF or calcium ionophore A 23187 were measured by single cell fluorescence technique. The ionophore A 23187 was able to induce calcium influx and an increase in cytoplasmic calcium concentration in LNCaP cells. In contrast, bFGF was incapable of eliciting a similar effect. In contrast to AR protein, AR mRNA levels were not affected by bFGF as shown by semiquantitative reverse transcription polymerase chain reaction. In summary, these studies show that bFGF is a potent negative regulator of AR protein expression in the human prostate cancer cell line LNCaP.

Calcium↗

PubMed2000

Renal cell carcinoma in a horseshoe kidney--superselective embolization of a vessel in a remaining calix after partial nephrectomy.

A 51-year-old patient underwent partial nephrectomy because of a renal cell carcinoma in a horseshoe kidney. Postoperatively a remaining calix led to persistent urinoma formation. By means of superselective embolization urine extravasation was stopped successfully. This demonstrates that superselective embolization can be an effective tool in the management of complications after open renal surgery.

Angiography↗

PubMed2000

Antagonist/agonist balance of the nonsteroidal antiandrogen bicalutamide (Casodex) in a new prostate cancer model.

Androgen ablation is standard therapy for advanced prostate carcinoma. It can be administered either as a monotherapy or as a combined androgen blockade. In the present study we have investigated molecular mechanisms which are responsible for the development of resistance to therapy in advanced prostate cancer. For this purpose, we have cultured LNCaP cells in steroid-depleted medium for 1 year. The newly generated subline LNCaP-abl was characterized. In early passages (<75) LNCaP-abl cells showed a biphasic hypersensitive response to androgenic stimulation. Passages later than 75 are inhibited by androgen. Proliferation of LNCaP-abl cells was stimulated by the pure nonsteroidal antiandrogen bicalutamide (Casodex). To improve our understanding of changes which occur during intermittent androgen ablation, we have generated the sublines LNCaP-R (reversal; cultured with fetal calf serum) and LNCaP-RA (reversal and androgen; cultured with fetal calf serum and androgen) from LNCaP-abl cells. In both cell lines an increase of the basal proliferation rate was observed. Androgen receptor expression in LNCaP-abl cells was 4-fold higher than that in parental LNCaP cells (4.7 vs. 1.2 fmol/microg protein). Androgen receptor content in LNCaP-R cells was 1.8 fmol/microg protein and in LNCaP-RA cells 1.0 fmol/microg protein. The basal androgen receptor activity was 30-fold higher in LNCaP-abl cells compared to that in parental LNCaP cells. This basal activity was reduced in LNCaP-RA cells. Both androgen and the nonsteroidal androgen receptor antagonist hydroxyflutamide induced a 2- to 4-fold higher activation of androgen receptor in LNCaP-abl than in LNCaP cells. There was a switch from an antagonist to an agonist of the nonsteroidal antiandrogen bicalutamide (Casodex) in LNCaP-abl cells. Antagonistic properties of this androgen receptor blocker were again observed in both sublines (LNCaP-R and LNCaP-RA) derived from LNCaP-abl cells. In concordance with proliferation data in vitro, growth of LNCaP-abl cells in nude mice was stimulated by bicalutamide. In contrast, supplementation of androgen led to inhibition of proliferation of these cells. The present study provides new information that is useful for a better understanding of therapy-refractory prostate cancer. It is also important for the development of new therapy strategies for advanced carcinoma of the prostate.

Androgen Antagonists↗

PubMed2000

Elevated levels of serum secretoneurin in patients with therapy resistant carcinoma of the prostate.

PURPOSE: The majority of prostate cancers show some degree of neuroendocrine differentiation. It was previously demonstrated that chromogranin A, a constituent of large dense core vesicles of neuroendocrine cells, is frequently elevated in patients with metastatic prostate cancer. We evaluate the expression of secretoneurin, which is generated by proteolytic processing of secretogranin II (chromogranin C), in patients with prostate disease. MATERIALS AND METHODS: Secretoneurin was measured in sera of 16 healthy men whose blood was drawn for prostate cancer screening (controls), and in 9 patients with prostatitis, 19 with benign prostate hyperplasia and 54 with prostate cancer detected by radioimmunoassay. Therapy resistant disease (clinical stage D3) was noted in 20 prostate cancer cases. Serum prostate specific antigen was measured in all patients and controls. In addition, chromogranin A, prostate acid phosphatase and interleukin-6 were determined in patients with D3 prostate cancer. Molecular properties of secretoneurin immunoreactivity were analyzed by gel filtration chromatography followed by radioimmunoassay. RESULTS: Mean secretoneurin was 58.9+/-8 fmol./ml. in patients with therapy resistant prostate cancer. Levels were significantly higher than those measured in sera from controls and patients with prostatitis, benign prostatic hyperplasia and pT2 or pT3 prostate cancer. There was a statistically significant correlation between secretoneurin and chromogranin A in patients with endocrine therapy failure (r = 0.543, p<0.05). There was no correlation between serum secretoneurin and prostate specific antigen, prostate acid phosphatase or interleukin-6. Gel filtration chromatography analysis of sera of 3 patients with D3 prostate cancer revealed a peak of secretoneurin immunoreactivity where intact secretoneurin elutes, thus showing that the processed peptide is circulating in the blood. CONCLUSIONS: Secretoneurin is elevated in sera of patients with endocrine therapy refractory prostate cancer. Our results support the concept that neuroendocrine differentiation is associated with prostate cancer progression.

Adult↗

PubMed2000

Laparoscopic retroperitoneal lymph node dissection for clinical stage I nonseminomatous testicular carcinoma: long-term outcome.

PURPOSE: We report the long-term oncological efficacy and morbidity of laparoscopic retroperitoneal lymph node dissection for testicular carcinoma. MATERIALS AND METHODS: From August 1992 to September 1999, 73 consecutive patients underwent laparoscopic retroperitoneal lymph node dissection with modified unilateral template dissection. All lumbar vessels within the template were routinely transected in the initial 29 cases only. Patients with positive lymph nodes received 2 cycles of chemotherapy. RESULTS: Operative time ranged from 150 to 630 minutes (mean 221) in our most recent 28 cases. All but 2 operations were completed as planned for a conversion rate of 2.7%. Minor intraoperative complications developed in only 6.8% of cases. In our last 44 patients there was no major and only 1 minor (2.3%) postoperative complication. Mean postoperative hospitalization was 3.3 days. Ejaculation was preserved in all patients. Lymph nodes were positive in 19 cases (26%). Mean followup in 47 patients with pathological stage I disease was 43.3 months (range 7 to 84). We noted 1 retroperitoneal recurrence due to false-negative histological findings but there were no other relapses. At a mean followup of 42.7 months (range 6 to 86) 17 patients with pathological stage II carcinoma treated with 2 cycles of adjuvant chemotherapy were also free of disease. CONCLUSIONS: In our hands laparoscopic retroperitoneal lymph node dissection has not only proved its surgical efficiency, but also its oncological efficacy. Patient satisfaction is high. During long-term followup of more than 3 years not a single recurrence developed due to surgical failure.

Adolescent↗

PubMed1999

Correlation between preoperative predictors and pathologic features in radical prostatectomy specimens in PSA-based screening.

BACKGROUND: Measurement of percent free prostate-specific antigen (PSA), PSA density, and PSA-transition zone density (PSA-TZ density) in addition to total PSA is known to improve the specificity of PSA-based prostate cancer screening. We evaluated the ability of total PSA, percent free PSA, PSA density, and PSA-TZ density to predict pathologic features in radical prostatectomy specimens. METHODS: The levels of total PSA, percent free PSA, PSA density, and PSA-TZ density assessed prior to the diagnosis of prostate cancer were correlated with the pathologic findings in 102 prostate glands with cancer obtained at radical prostatectomy. The entire organs were examined histologically; Pearson correlation coefficients were used for statistical analysis. RESULTS: High levels of total PSA, PSA density, and PSA-TZ density correlated significantly with capsular penetration, high Gleason scores, and large cancer volumes in the prostatectomy specimens. Free PSA was found to correlate well with high Gleason scores, high percentages of cancer, and large cancer volumes, but not with capsular penetration. The four parameters were evaluated by means of logistic regression, which showed that only percent free PSA and total PSA were significant predictors of Gleason scores > or =7 and cancer volumes > or =0.5 cc. With regard to clinically insignificant cancers, only percent free PSA and the Gleason score obtained at biopsy were significant predictors. CONCLUSIONS: In men whose prostate cancers are detected by PSA-based screening, high total PSA levels in combination with low percent free PSA levels are suggestive of a potentially more aggressive type of prostate cancer. This may help both patient and clinician in selecting the most appropriate therapeutic approach.

Adult↗

PubMed1999

Cytogenetic characterization of 22 human renal cell tumors in relation to a histopathological classification.

In this study, cytogenetic and fluorescence in situ hybridization analyses were performed on 22 sporadic, unilateral primary renal cell tumors. The tumors were classified according to cell types, growth patterns, and grades of malignancy. A feeder layer technique was used for the cell culture of 13 clear-cell carcinomas, 4 chromophilic carcinomas, 3 chromophobe carcinomas, 1 oncocytoma, and 1 spindle-shaped pleomorphic carcinoma. Eighty-six percent (19/22) of renal tumors showed clonal abnormalities. The most frequent finding in the 15 male patients was loss of chromosome Y (9/15). In 3/15, it was the only observed aberration. The second most visible aberration was regional loss or entire loss of chromosome 9, which was detected in 36% (8/22) of the cases. Four cases showed loss of chromosome 9 and 4 cases a deletion of the short arm with breakpoints on 9p11 and 9p21. Loss of 3p material was observed in 32% (7/22) of the cases but only in 2/13 patients with clear-cell carcinoma. Gain of chromosome 12 or 12p was observed in 27% (6/22). In 23% (5/22) of the patients, gain of whole or partial chromosomes 2, 5, and 7 was found. Less-frequent findings were loss of chromosomes 8, 14, and 21; gain of chromosome 16; and structural abnormalities of chromosome 1 (each 18%; 4/22). Only some of the karyotypes described as typical for the various renal tumor types were confirmed. In contrast with previous reports, chromosome 3 and 9 aberrations did not allow differentiation between tumor types in our study.

Aged↗

PubMed1999

Switch from antagonist to agonist of the androgen receptor bicalutamide is associated with prostate tumour progression in a new model system.

Advanced prostate cancer is treated by androgen ablation and/or androgen receptor (AR) antagonists. In order to investigate the mechanisms relevant to the development of therapy-resistant tumours, we established a new tumour model which closely resembles the situation in patients who receive androgen ablation therapy. Androgen-sensitive LNCaP cells were kept in androgen-depleted medium for 87 passages. The new LNCaP cell subline established in this manner, LNCaP-abl, displayed a hypersensitive biphasic proliferative response to androgen until passage 75. Maximal proliferation of LNCaP-abl cells was achieved at 0.001 nM of the synthetic androgen methyltrienolone (R1881), whereas 0.01 nM of this compound induced the same effect in parental cells. At later passages (> 75), androgen exerted an inhibitory effect on growth of LNCaP-abl cells. The non-steroidal anti-androgen bicalutamide stimulated proliferation of LNCaP-abl cells. AR protein expression in LNCaP-abl cells increased approximately fourfold. The basal AR transcriptional activity was 30-fold higher in LNCaP-abl than in LNCaP cells. R1881 stimulated reporter gene activity in LNCaP-abl cells even at 0.01 nM, whereas 0.1 nM of R1881 was needed for induction of the same level of reporter gene activity in LNCaP cells. Bicalutamide that acts as a pure antagonist in parental LNCaP cells showed agonistic effects on AR transactivation activity in LNCaP-abl cells and was not able to block the effects of androgen in these cells. The non-steroidal AR blocker hydroxyflutamide exerted stimulatory effects on AR activity in both LNCaP and LNCaP-abl cells; however, the induction of reporter gene activity by hydroxyflutamide was 2.4- to 4-fold higher in the LNCaP-abl subline. The changes in AR activity were associated neither with a new alteration in AR cDNA sequence nor with amplification of the AR gene. Growth of LNCaP-abl xenografts in nude mice was stimulated by bicalutamide and repressed by testosterone. In conclusion, our results show for the first time that the nonsteroidal anti-androgen bicalutamide acquires agonistic properties during long-term androgen ablation. These findings may have repercussions on the natural course of prostate cancer with androgen deprivation and on strategies of therapeutic intervention.

Androgen Antagonists↗

PubMed1999

Mechanism of androgen receptor activation and possible implications for chemoprevention trials.

Androgens are pivotal regulators of prostate cell growth, differentiation and function, and their actions are believed to be involved in prostate cancer development. The androgen-signaling pathway in the prostate gland is therefore one of the possible sites of intervention in prostate cancer prevention efforts. The central element of androgen signaling in the cell is the androgen receptor (AR), a member of the superfamily of nuclear receptors. Binding of androgen to its ligand-binding domain transforms the receptor to an active transcription factor that regulates gene expression by interacting with specific regulatory elements in the promoters of genes. In addition to this genomic action, the AR also interacts with other signaling pathways through protein-protein interaction, for example with AP-1 or Ets transcription factors. It is not only the action of androgenic hormones, but also the interactions with growth factor and protein kinase A-signaling pathways that can induce activation of AR. Moreover, these ligand-independent activators act synergistically together with low concentrations of androgens. The effects of long-term androgen deprivation on androgen signaling have been investigated in the LNCaP cell culture system. Long-term culture in a steroid-free medium results in a subline showing a hyperreactive AR characterized by increased AR expression and enhanced AR transcriptional activity in an environment with low levels of androgen hormones. It is not yet clear if similar changes also occur in normal or premalignant prostate epithelial cells and are thus relevant for prevention trials which interfere with androgen hormone signaling.

Antineoplastic Agents↗

PubMed1999

Laparoscopic retroperitoneal lymphadenectomy after chemotherapy for stage IIB nonseminomatous testicular carcinoma.

PURPOSE: We investigated laparoscopic retroperitoneal lymphadenectomy after chemotherapy for stage IIB testicular carcinoma in terms of operative feasibility, overall morbidity and tumor control. MATERIALS AND METHODS: Between February 1995 and April 1998, 24 patients underwent laparoscopic retroperitoneal lymphadenectomy following initial chemotherapy for stage IIB (2 to 5 cm.) solitary or unilateral lymph node metastases. Mean tumor diameter was 2.4 cm. before and 1.1 cm. after chemotherapy. Laparoscopic retroperitoneal lymphadenectomy was performed in all patients, including those with complete remission. RESULTS: Laparoscopic retroperitoneal lymphadenectomy could be completed as planned in all patients and there was no need for conversion to open surgery. Operative time was 150 to 300 minutes (mean 240). Blood loss was minimal and no blood transfusions were required. The only postoperative complications were chylous ascites (5 patients) which resolved with conservative management (low fat diet) and a small asymptomatic lymphocele. Histological examination revealed necrosis in 71%, mature teratoma in 25% and active tumor in 4% of patients. Antegrade ejaculation was preserved in all patients. Mean postoperative hospital stay was 4 days, return to normal activities between 1 and 3 weeks, and time to complete recovery between 5 and 10 weeks. All patients were well without evidence of disease at a mean followup of 24.4 months. CONCLUSIONS: Laparoscopic retroperitoneal lymphadenectomy after chemotherapy proved feasible in select patients presenting with solitary or unilateral lymph node metastases and was associated with a low morbidity. Tumor control was not compromised by the laparoscopic approach.

Adolescent↗

PubMed1998

Interleukin-6 regulates prostate-specific protein expression in prostate carcinoma cells by activation of the androgen receptor.

Interleukin-6 (IL-6) levels are frequently elevated in sera of patients with metastatic prostate cancer. IL-6 receptors are expressed in prostate cancer cell lines, as well as in benign prostate hyperplasia and prostate cancer tissue specimens. The androgen receptor (AR) is a key transcription factor that is present in all stages of prostate carcinoma, even in therapy-refractory tumors. In an attempt to investigate possible cross-talk between IL-6 and androgen signal transduction cascades, we tested the effects of this cytokine on AR transcriptional activity. The regulation of AR activity by IL-6 was studied in DU-145 cells, which were cotransfected with the androgen-responsive reporter plasmid ARE2TATACAT and the AR expression vector pSG5AR. We show that IL-6 up-regulates AR activity in a ligand-independent manner, as well as synergistically, with very low doses of the synthetic androgen methyltrienolone (5-10 pM). Therefore, AR activation by IL-6 may be operative in prostate cancer patients who have decreased androgen levels because of androgen ablation therapy. The maximal induction of reporter gene activity by IL-6 alone (50 ng/ml) was 67% of that stimulated by 1 nM of methyltrienolone. The nonsteroidal antiandrogen bicalutamide (Casodex) nearly completely inhibited AR activation by IL-6. IL-6 effects on AR activity were also abolished or greatly reduced by inhibitors of protein kinase A and C and mitogen-activated protein kinase pathways. In concordance with the results obtained in DU-145 cells, IL-6 induced AR-regulated prostate-specific antigen mRNA and protein in LNCaP cells. Stimulation of prostate-specific antigen protein secretion by IL-6 was antagonized by bicalutamide and inhibitors of protein kinase A and mitogen-activated protein kinase signaling pathways. Taken together, our data show for the first time that IL-6 is a nonsteroidal activator of the AR and that this activation is implicated in the regulation of prostate-specific proteins. Keeping in mind that IL-6, its receptor, and the AR are expressed in prostate cancers, cross-talk between IL-6 and AR signaling pathways may have clinical significance.

Down-Regulation↗

PubMed1998

Expression of Lewis carbohydrate antigens in metastatic lesions from human prostatic carcinoma.

BACKGROUND: Monoclonal antibodies B1 and B3 react with Lewis(y) and related carbohydrate antigens, which are abundant in many solid tumors. These antibodies, when conjugated to a toxin, have been used to target a variety of cancers. Treatment options for advanced prostate cancer are very limited, and there is a need to develop new therapies. In this study, we have asked whether antibodies B1 and B3 react with metastatic lesions from human prostatic carcinoma. METHODS: Indirect streptavidin-biotin peroxidase immunohistochemistry was performed on formalin-fixed specimens from prostate cancer metastases. A total of 6 lymph node metastatic samples from patients who did not receive endocrine treatment and specimens of 14 distant metastases from patients who failed hormonal therapy were obtained. RESULTS: Of the samples, 6 lymph node and 11 distant metastases stained for B1. In the case of B3 staining, 6 lymph node and 10 distant metastatic lesions were positive. In about half of these metastatic samples, more than 40% of cells were immunoreactive with either antibody. Two metastatic samples stained neither for B1 nor for B3 antibody. In general, B1 staining intensity was stronger in samples in which more than 40% of cells were positive. CONCLUSIONS: Our results suggest that B1 and B3 immunoconjugates could be applied to target a substantial percentage of prostate cancer metastases.

Antibodies, Monoclonal↗

PubMed1998

Expression, structure, and function of androgen receptor in advanced prostatic carcinoma.

BACKGROUND: Endocrine therapy for prostate cancer aims to reduce the levels of circulating androgen or to inhibit androgen action by blocking the androgen receptor in the prostate, or both. Studies in various animal and human prostate cancer models suggested that there may be a downregulation of androgen receptor during prostate cancer progression. Recent work, however, showed androgen receptor expression in all stages of prostate cancer. The presence of mutant androgen receptors in a portion of prostate cancers and receptor activation in the absence of androgen or in the presence of low androgen concentrations is discussed within this context. METHODS: This review attempts to summarize the literature on androgen receptor expression in vitro and in vivo, as well as structural and functional alterations and communication between androgen signal transduction cascade and other signaling pathways. CONCLUSIONS: Prostate tumors adapt to an environment with low androgen supply by using a hyperactive androgen receptor. The mechanisms involved are mutations of the androgen receptor generating receptors with broadened activation spectrum, increased receptor expression, and activation by interaction with other signaling pathways.

Androgen Antagonists↗

PubMed1998

Interleukin 1beta mediates the modulatory effects of monocytes on LNCaP human prostate cancer cells.

Proliferative and secretory responses in androgen-sensitive prostate cancer LNCaP cells are regulated by steroid and peptide hormones and by differentiation-promoting substances. In the present study, we evaluated whether peripheral blood monocytes that exhibit anti-tumour activity in haematopoietic and solid tumours influence growth and secretion in the LNCaP cell line. For this purpose, LNCaP cells were incubated with monocyte-conditioned medium (MCM), and proliferation as well as expression of androgen receptor (AR) and secretion of prostate-specific antigen (PSA) were assessed. Conditioned medium from monocytes reduced proliferation in a dose-dependent manner. Incubation with 40% MCM caused a 50% reduction in cell proliferation. AR protein decreased by 70% and PSA levels in supernatants from LNCaP cells were reduced by approximately 80% following treatment with MCM. We focused on the contribution of two major products of activated monocytes, prostaglandin E2 and interleukin 1beta (IL-1beta), to the MCM modulatory action. LNCaP cells treated with prostaglandin E2 showed neither a reduction in proliferation nor a down-regulation of AR and PSA levels. The effects of MCM on cellular proliferation, AR protein and PSA secretion were abolished by pretreatment of MCM with a neutralizing anti-IL-1beta antibody. In addition, recombinant IL-1beta was able to replace MCM for the inhibition of proliferation and down-regulation of AR and PSA proteins. LNCaP cells were shown to express the IL-1beta receptor type 1, which transduces IL-1beta signal. Our findings reveal that monocyte-derived IL-1beta inhibits the proliferation of androgen-responsive prostate tumour cells and reduces AR and PSA levels.

Cell Division↗