Home About us Contact
|
Home About us Contact | ||
|
|
||
Serum Prostate Specific Antigen (serum + prostate_specific_antigen)
Selected AbstractsRegulation of PSA secretion and survival signaling by calcium-independent phopholipase A2, in prostate cancer cellsTHE PROSTATE, Issue 12 2009Thomas M. Nicotera Abstract BACKGROUND Serum prostate specific antigen (PSA) levels in prostate cancer patients serve as a useful biomarker for diagnosing and monitoring prostate cancer. Recently, secreted PSA has been characterized as an autocrine survival factor through activation of Akt and induction of AR. In the normal prostate, PSA is secreted in the lumen of prostatic ducts to lyse proteins in the seminal coagulum. METHODS However, the mechanism for constitutive PSA secretion from benign prostate and its transport across the prostate-blood barrier into serum are unknown. Regulation of peptide secretion by iPLA2 -, has been reported in non-prostatic tissue and in prostate tissue iPLA2 -, is reported to be under androgen regulation. We investigated whether iPLA2 plays a role for in PSA secretion by comparing iPLA2 activity and expression in normal prostate epithelial RWPE-1 cells and in LNCaP prostate cancer cells. Expression of the two active iPLA2 -, mRNA splice variants, LH-iPLA2 and SH-iPLA2, were increased and the inhibitory ankyrin-iPLA2 isoform was markedly reduced in LNCaP cells as compared to normal prostate epithelial RWPE-1 cells. RESULTS These changes are consistent with a higher enzymatic activity in LNCaP cells. The iPLA2 -,-specific inhibitor BEL inhibited PSA secretion and induced apoptosis in LNCaP cells. iPLA2 knockdown using SiRNA inhibited PSA secretion, downregulated AR and induced apoptosis. Exogenous PSA suppressed BEL-induced apoptosis and neutralizing anti-PSA antibody blocked the survival effect of PSA. CONCLUSIONS These data indicate that iPLA2 -, participates in regulating PSA secretion and supports the concept that secreted PSA provides an autocrine survival function in LNCaP cells. Prostate 69:1270,1280, 2009. © 2009 Wiley-Liss, Inc. [source] Expression of BAG-1 protein correlates with aggressive behavior of prostate cancers,,THE PROSTATE, Issue 8 2006Maryla Krajewska Abstract Background Differences in tumor behavior, ranging from indolent to aggressive, create a need for novel prognostic biomarkers. BAG-1 is a co-chaperone that regulates the activity of Hsp70, Bcl-2, Raf-1, growth factor, and steroid receptors (e.g., the Androgen Receptor). Methods Using immunohistochemical method, we explored BAG-1 expression in prostate cancers and its association with clinicopathological parameters. Results BAG-1 immunostaining was elevated in prostate cancer compared to normal prostatic epithelium. Higher nuclear BAG-1 in hormone-refractory (n,=,34) compared to localized untreated tumors (n,=,58) (P,<,0.0001) suggested that upregulation of the nuclear isoform may contribute to disease progression. In 64 early-stage patients (T2N0M0) treated with external-beam irradiation, cytosolic BAG-1 correlated with higher pretreatment levels of serum Prostate specific antigen (P,=,0.04) and shorter time to disease progression (P,=,0.00004). Conclusions Increased cytosolic and nuclear BAG-1 expression may denote more aggressive variants of prostate cancer. Prostate © 2006 Wiley-Liss, Inc. [source] Amino-terminus domain of the androgen receptor as a molecular target to prevent the hormonal progression of prostate cancerJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2006Gang Wang Abstract Prostate cancer has a propensity to metastasize to the bone. Currently the only effective systemic treatment for these patients is androgen ablation therapy. However, the tumor will invariably progress to an androgen-independent stage and the patient will succumb to his disease within approximately 2 years. The earliest indication of hormonal progression is the rising titer of serum prostate specific antigen. Current evidence implicates the androgen receptor (AR) as a key factor in maintaining the growth of prostate cancer cells in an androgen-depleted state. Under normal conditions, binding of ligand activates the receptor, allowing it to effectively bind to its respective DNA element. However, AR is also transformed in the absence of androgen (ligand-independent activation) in prostate cells via multiple protein kinase pathways and the interleukin-6 (IL-6) pathway that converge upon the N-terminal domain of the AR. This domain is the main region for phosphorylation and is also critical for normal coregulator recruitment. Here we discuss evidence supporting the role of the AR, IL-6 and other protein kinase pathways in the hormonal progression of prostate cancer to androgen independence and the mechanisms involved in activation of the AR by these pathways. Receptor-targeted therapy, especially potential drugs targeting the N-terminal domain, may effectively prevent or delay the hormonal progression of AR-dependent prostate cancer. J. Cell. Biochem. 98: 36,53, 2006. © 2006 Wiley-Liss, Inc. [source] In vivo real-time imaging of TGF-,-induced transcriptional activation of the RANK ligand gene promoter in intraosseous prostate cancerTHE PROSTATE, Issue 4 2004Jian Zhang Abstract BACKGROUND Current animal models of prostate cancer (CaP) bone metastasis do not allow measurement of either tumor growth in bone over time or activation of gene promoters in intraosseous tumors. To develop these methods, we used bioluminescent imaging (BLI) to determine if expression of receptor activator of NF-,B ligand (RANKL), a pro-osteoclastogenic factor that promotes CaP bone metastases, is modulated by the bone matrix protein transforming growth factor-, (TGF-,) in vivo. METHODS C4-2B human CaP cells were treated with TGF-, in vitro and RANKL mRNA and protein production were measured by polymerase chain reaction (PCR) and ELISA, respectively. Then C4-2B cells stably transfected with the RANKL promoter driving luciferase (lux) were injected intra-tibially into severe combined immundeficient (SCID) mice. Tumors were subjected to BLI every 2 weeks for 6 weeks and serum prostate specific antigen (PSA) was measured using ELISA. Vehicle (V), 1,25 dihydroxyvitamin D (VitD), or TGF-, was administered to mice with established tumors and BLI to measure RANKL promoter activity was performed. Tumors were then subjected to immunohistochemistry for lux and assayed for RANKL mRNA levels. RESULTS TGF-, induced RANKL protein and mRNA expression and activated the RANKL promoter activity in a dose-dependent manner in vitro. BLI demonstrated an increase in intraosseous tumor size over time, which correlated with serum PSA levels. Administration of TGF-, and VitD to mice with established intraosseous tumors increased lux activity compared to V. Intratibial tumor RANKL mRNA expression paralleled the increased promoter activity. Immunohistochemistry confirmed the presence of lux in the intraosseous tumors. CONCLUSIONS These results demonstrate the ability to measure intraosseous tumor growth over time and gene promoter activation in an established intraosseous tumor in vivo and also demonstrate that TGF-, induces activates the RANKL promoter. These results provide a novel method to explore the biology of CaP bone metastases. © 2004 Wiley-Liss, Inc. [source] Response of patients with advanced prostatic cancer to administration of somatostatin analog RC-160 (vapreotide) at the time of relapseTHE PROSTATE, Issue 3 2003David González Barcena Abstract BACKGROUND The aim of this study was to evaluate the effects of administration of the somatostatin analog RC-160 (vapreotide) at the time of relapse in patients with androgen independent prostate cancer. METHODS Our study included 13 patients with biopsy-proven prostate cancer, stage D3. Eight patients had been treated with a depot formulation of the agonist D-Trp-6-LH-RH, with a median remission time of 68 (range 48,102 months). Five patients were initially treated by surgical orchiectomy, but relapsed after a median time of 33 months (range 17,91 months). A new remission period with a median duration of 10 months (range 2,29 months) was induced with Ketoconazole in the orchiectomy group. At the relapse time, all the patients received 1 mg of vapreotide t.i.d., by subcutaneous route, in addition to D-Trp-6-LH-RH, or Ketoconazole in the orchiectomy group. RESULTS Eight of 13 patients demonstrated clinical improvement after 3 months of therapy with vapreotide, six showing a decrease in serum prostate specific antigen (PSA) from 234.5,±,308.5 to 68.2,±,60.5 ng/ml (mean decline 71,±,8%; P,<,0.05). Two additional patients presented a fall in serum prostatic acid phosphatase (PAP). Responding patients showed a decrease in the bone pain score from 2.62,±,0.48 to 0.37,±,0.69 and an increase in the Karnofsky performance status from 72.3,±,4.21 to 83.6,±,23.2 (P,<,0.05). In accord with the ECOG criteria, two patients had a complete response; four had partial response, and two had a stable response. Four patients did not respond and one was not evaluable. Two patients died in remission, one at 16 months due to myocardial infarction and the other at 24 months due to pneumonia. Three patients relapsed at 5, 17, and 19 months respectively. Three patients who have been followed-up for more than 3 years continued in remission (79, 45, and 45 months) respectively. Vapreotide was well tolerated, only three patients having transitory mild diarrhea. CONCLUSIONS Our results indicate that therapy with the somatostatin analog vapreotide at the time of relapse can induce objective clinical responses in some patients with prostate cancer who are refractory to androgen ablation induced by LH-RH analogs or orchiectomy. Prostate 56: 183,191, 2003. © 2003 Wiley-Liss, Inc. [source] Possible mechanism of dexamethasone therapy for prostate cancer: Suppression of circulating level of interleukin-6THE PROSTATE, Issue 2 2003Koichiro Akakura Abstract BACKGROUND Glucocorticoids may have favorable effects on prostate cancer patients showing clinical and/or biochemical failure after androgen ablation. The efficacy and mechanisms of dexamethasone therapy as possible alternative endocrine therapy were investigated. METHODS Twenty five patients with prostate cancer treated by androgen ablation and showing a steady increase in serum prostate specific antigen (PSA) were treated with low-dose dexamethasone. RESULTS Of 25 patients, 11 demonstrated 50% or more decline of serum PSA and 9 showed improvement of pain on dexamethasone therapy. Of 8 patients who responded to dexamethasone thearpy, 5 had 80% or more decrease in serum interleukin-6 (IL-6). In contrast, none of 8 non-responders showed remarkable IL-6 suppression. Response of PSA was not correlated to the changes in serum dehydroepiandrosterone, dehydroepiandrosterone sulfate, or androstendione. CONCLUSIONS Significant suppression of serum IL-6, probably through inhibition of androgen-independent activation of androgen receptor, may be one of the mechanisms for the effect of dexamethasone therapy in prostate cancer patients with progressive disease. Prostate 56: 106,109, 2003. © 2003 Wiley-Liss, Inc. [source] Evaluation of the safety, pharmacokinetics and treatment effects of an ,,,3 integrin inhibitor on bone turnover and disease activity in men with hormone-refractory prostate cancer and bone metastasesASIA-PACIFIC JOURNAL OF CLINICAL ONCOLOGY, Issue 1 2010Mark A ROSENTHAL Abstract Aim: This study aimed to evaluate the safety, pharmacokinetics and treatment effects of an ,,,3 integrin inhibitor on bone turnover and disease activity in men with hormone-refractory prostate cancer (HRPC) and bone metastases. Methods: A total of 21 patients with bone metastases and HRPC were randomized to receive MK-0429 200 mg b.i.d. or 1600 mg b.i.d. for 4 weeks. Toxicity, pharmacokinetics and markers of bone turnover and tumor activity were examined. Results: Nausea was the most common adverse event: one (200-mg group) and 11 (1600-mg group) patients. At 4 weeks, mean AUC0,12 h was 210 mmol*h (200-mg group) and 673 mmol*h (1600-mg group); mean Cmax values were 42 mmol/L (200-mg group) and 154 mmol/L (1600-mg group). Urinary cross-linked N-telopeptides of type I collagen to creatinine ratio (uNTx), a bone turnover biomarker, showed a change from baseline of ,43.4 percent (200-mg group) and ,34.1 percent (1600-mg group). There was an increase in serum prostate specific antigen (PSA), a marker for disease activity, of 54.1 percent (200-mg group) and 44.5 percent (1600-mg group). Conclusion: MK-0429 was generally well tolerated, with the most common side-effect being nausea. There was some evidence of an early reduction of bone turnover, indicating a potential for clinical use in the treatment of MBD although serum PSA was unexpectedly increased during the study. [source] A multiinstitutional, concurrent chemoradiation trial of strontium-89, estramustine, and vinblastine for hormone refractory prostate carcinoma involving boneCANCER, Issue 6 2002Wallace Akerley M.D. Abstract BACKGROUND Estramustine phosphate (EMP) and vinblastine have radiosensitizing properties and significant activity against hormone refractory prostate carcinoma. Strontium-89 is a palliative agent that acts as a selective radiation source for bone metastasis. The combination of EMP, vinblastine, and strontium-89 was developed to exploit the potential for radiosynergy. PATIENTS AND METHODS Forty-four patients at the Brown Oncology Group affiliated hospitals were treated with oral EMP 600 mg/m2 daily on Weeks 1,4 and 7,10, vinblastine 4 mg/m2 intravenously once each week on Weeks 1,4 and 7,10, and strontium-89 2.2 MBq/kg on Day 1. Courses were repeated every 12 weeks. Response assessment was based on a change in the serum prostate specific antigen (PSA) levels, correlated with change in measurable disease and bone scan appearance. RESULTS A greater than or equal to 50% decline in PSA for at least 6 weeks was observed in 21 patients (48%, 95% confidence interval, 33,62%). Median duration of response was 23 weeks (range, 6,70.8 weeks). The median survival was 13 months with 1- and 2-year survival rates of 55% and 25%, respectively. After completion of protocol therapy, a retrospective review showed that only nine patients received subsequent palliative external beam radiation after progression. CONCLUSIONS The addition of strontium-89 to the regimen of EMP and vinblastine can be delivered safely and in repeated doses, provides effective palliation, and may decrease the need for future radiation therapy. A randomized trial is necessary to quantify these effects. Cancer 2002;94:1654,60. © 2002 American Cancer Society. DOI 10.1002/cncr.10437 [source] Rapid rise of serum prostate specific antigen levels after discontinuation of the herbal therapy PC-SPES in patients with advanced prostate carcinomaCANCER, Issue 3 2002Report of four cases Abstract BACKGROUND PC-SPES is an herbal supplement whose mechanisms of action are poorly understood, but may be estrogenic. The objective of the current report is to describe the effects of discontinuing PC-SPES treatment in four patients with androgen-independent prostate carcinoma. METHODS Patient charts were retrospectively reviewed. A MEDLINE search was performed to investigate whether these effects of PC-SPES had been previously reported. RESULTS Four men whose metastatic prostate carcinoma progressed despite androgen ablation and subsequent PC-SPES treatment are described. All four patients developed a rapid increase in serum prostate specific antigen (PSA) within one month of stopping PC-SPES, ranging from 345% to 880%. Two patients increased their PSA levels to 1300% and 1400% after 7 weeks. Compared to the rate of rise of PSA levels prior to and during PC-SPES therapy, the rise after stopping this treatment was much higher than expected. Clinical symptoms remained relatively stable despite the serologic changes. CONCLUSIONS Discontinuing PC-SPES therapy can be associated with a rapid rise in PSA. To the authors' knowledge, this effect has not been reported previously. This effect should be considered in the design of clinical trials as well as in the standard management of androgen-independent prostate carcinoma patients. Cancer 2002;94:686,9. © 2002 American Cancer Society. DOI 10.1002/cncr.10269 [source] | ||||||||||