Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027627 (metastases)
 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Radical prostatectomy as a primary treatment for clinically localized prostate cancer has increased dramatically over the past decade due to prostate-specific antigen (PSA) screening and the awareness of the increased incidence of localized disease. Despite the stage migration to increase clinically localized disease, there are still vast numbers of men who harbor occult extraprostatic extension and develop recurrence after surgery. The study of molecular markers in the blood or tissue of surgical patients prior to treatment, called " molecular staging, " is the focus of this review. The reverse transcriptase- polymerase chain reaction (RT-PCR) test for PSA gene expression in peripheral blood or bone marrow has received considerable attention since its first report in 1992. The test detects messenger RNA species for prostate-specific/abundant genes such as PSA and prostate-specific membrane antigen. These messenger RNAs were not detected in normal blood or bone marrow, but were detected in some prostate cancer patients presumably due to circulating prostatic epithelial cells. These prostate epithelial cells are thought to be occult metastases cells, and early studies correlated a positive RT-PCR test with surgical pathology adverse features such as positive margins. Despite the many studies over the past few years, there have been inconsistent results, and the most recent studies have not been able to confirm clinical utility. Bone marrow RT-PCR has been more promising; however, it is still a research tool that needs further study. The study of molecular markers in tissue material, ie, prostate biopsy samples prior to radical prostatectomy, is problematic due to the sampling error inherent in a multifocal heterogeneous tumor such as prostate cancer. The tumor suppressor proteins p53 and p27, Bcl-2 oncoprotein, Ki-67 proliferation index protein, E-cadherin, and microvessel density have been assessed in preradical prostatectomy needle biopsy. Results have been conflicting, and none are yet accepted as a clinically useful marker. Current and future work is focusing on analysis of multiple gene expressions or proteins simultaneously via gene chip or proteomics technology. While these expression profiles might be of value in whole prostate surgical specimens where tissues are well characterized, it is unclear how this new technology will be applied to the needle biopsy samples. Although molecular staging of radical prostatectomy patients has been under study for a decade, all assays remain research tools. Still, this area holds great promise for improving the accuracy of staging and providing a more accurate prognosis of individual men with clinically localized prostate cancer.
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PMID:Molecular markers in prostate cancer: the role in preoperative staging. 1504 12

Limited options for the treatment of prostate cancer have spurred the search for new therapies. One innovative approach is the use of targeted alpha therapy (TAT) to inhibit cancer growth, using an alpha particle emitting radioisotope such as (213)Bi. Because of its short range and high linear energy transfer (LET), alpha-particles may be particularly effective in the treatment of cancer, especially in inhibiting the development of metastatic tumors from micro-metastases. Prostate-specific membrane antigen (PSMA) is expressed in prostate cancer cells and the neovasculature of a wide variety of malignant neoplasms including lung, colon, breast and others, but not in normal vascular endothelium. The expression is further increased in higher-grade cancers, metastatic disease and hormone-refractory prostate cancer (PCA). J591 is one of several monoclonal antibodies (mabs) to the extracellular domain of PSMA. Chelation of J591 mab with (213)Bi forms the alpha-radioimmunoconjugate (AIC). The objective of this preclinical study was to design an injectable AIC to treat human prostate tumors growing subcutaneously in mice. The anti-proliferative effects of AIC against prostate cancer were tested in vitro using the MTS assay and in vivo with the nude mice model. Apoptosis was documented using terminal deoxynucleotidyl transferase [TdT]-mediated deoxyuridinetriphosphate [dUTP] nick end-labeling (TUNEL) assay, while proliferative index was assessed using the Ki-67 marker. We show that a very high density of PSMA is expressed in an androgen-dependent human PCA cell line (LNCaP-LN3) and in tumor xenografts from nude mice. We also demonstrate that the AIC extensively inhibits the growth of LN3 cells in vitro in a concentration-dependent fashion, causing the cells to undergo apoptosis. Our in vivo studies showed that a local AIC injection of 50 microCi at 2 days post-cell inoculation gave complete inhibition of tumor growth, whereas results for a non-specific AIC were similar to those for untreated mice. Further, after 1 and 3 weeks post-tumor appearance, a single (100 microCi/100 microl) intra-lesional injection of AIC can inhibit the growth of LN3 tumor xenografts (volume<100 mm(3)) in nude mice. Tumors treated with AIC decreased in volume from a mean 46+/-14 mm(3) in the first week or 71+/-15 mm(3) in the third week to non-palpable, while in control mice treated with a non-specific AIC using the same dose, tumor volume increased from 42 to 590 mm(3). There were no observed side effects of the treatment. Because of its in vitro cytotoxicity and these anti-proliferative properties in vivo, the (213)Bi-J591 conjugate has considerable potential as a new therapeutic agent for the treatment of prostate cancer.
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PMID:In vitro and preclinical targeted alpha therapy of human prostate cancer with Bi-213 labeled J591 antibody against the prostate specific membrane antigen. 1519 29

ProstaScint (CYT-356 or capromab pendetide, Cytogen) is an 111In-labeled monoclonal mouse antibody specific for prostate-specific membrane antigen, a prostate transmembrane glycoprotein that is upregulated in prostate adenocarcinoma. ProstaScint scans are US Food and Drug Administration approved for pretreatment evaluation of metastatic disease in high-risk patients. They are also approved for post-prostatectomy assessment of recurrent disease in patients with a rising prostate-specific antigen level. This review explores the literature on ProstaScint and its use in guiding the treatment of prostate cancer. A novel technique for identifying areas of cancer within the prostate using ProstaScint images fused with pelvic computed tomography scans is also described. The identification of areas of high antibody signal provides targets for radiotherapeutic dose escalation, with the overall goals of improving treatment outcome while preserving adjacent tissue structures and decreasing treatment morbidity.
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PMID:Role of ProstaScint for brachytherapy in localized prostate adenocarcinoma. 1522 91

Radical prostatectomy should ideally be curative for all patients with clinically localized prostate cancer (PrCa), yet a sizeable proportion of them eventually relapse. We examined in this setting the feasibility of pre-operative risk stratification for early post-operative relapse using reverse transcriptase polymerase chain reaction (RT-PCR) for prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA) transcripts in preoperative bone marrow (BM) biopsies and peripheral blood (PBL) samples. Nested RT-PCR for PSA and PSMA transcripts were performed in RNA from BM biopsies and PBL samples prospectively obtained from 111 men newly diagnosed, by trans-rectal ultrasound (TRUS)-guided biopsy, with clinically localized PrCa and scheduled to undergo radical prostatectomy, according to their respective doctors' recommendation. Molecular analysis for each sample (PBL or BM) was considered positive only if both PSA and PSMA transcripts were detectable. Serial serum PSA level measurements served for biochemical follow-up and detection of biochemical failure (PSA >0.2 ng/ml). PBL and BM RT-PCR molecular staging delineated three groups of patients (a) PBL-BM- (72 patients, 65%), (b) PBL+BM+ (29 patients, 26%), and (c) PBL+BM- (10 patients, 9%). These three groups corresponded to low, high, and intermediate risk for early post-prostatectomy recurrence (median time to biochemical failure of >38, 8, and >28 months, respectively). Multivariate analysis confirmed that molecular staging status was independent predictor of disease-free survival, after adjusting for PSA levels and Gleason score. In clinically localized PrCa, combined PSA/PSMA RT-PCR in PBL and BM is an independent predictor of time to biochemical failure following radical prostatectomy.
Clin Exp Metastasis 2004
PMID:Molecular staging by RT-pCR analysis for PSA and PSMA in peripheral blood and bone marrow samples is an independent predictor of time to biochemical failure following radical prostatectomy for clinically localized prostate cancer. 1567 47

Our aim is the identification and correlation of changes in tumor-associated protein expression which results from therapy. LNCaP tumors, excised from nude mice treated either by orchiectomy or with the chemotherapeutic agent paclitaxel, were evaluated for the expression of proteins and receptors associated with growth, differentiation, and angiogenesis using immunohistologic procedures. Compared to untreated control tumors, both treatments reduced the expression of vascular endothelial growth factor (VEGF), prostate-specific membrane antigen (PSMA), prostate-specific antigen (PSA), androgen receptor (AR), and epidermal growth factor receptor (EGFR). The effect of paclitaxel treatment on AR expression was the most significant (P = .005). Of particular interest was identifying a significant correlation (P < .000801) between PSMA and VEGF expression regardless of treatment modality. These altered expressions suggest that PSMA may also be a marker for angiogenesis and could represent a target for deliverable agents recognizing either prostatic tumors or endothelial development. Cell surface PSMA would then present a unique target for treatment of patients early in their development of prostatic metastases.
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PMID:Correlation between PSMA and VEGF expression as markers for LNCaP tumor angiogenesis. 1619 87

The ability to label tissue-specific antibodies has long been of interest for improving detection and guidance for therapeutic applications. The most studied target for prostate cancer is the prostate-specific membrane antigen, which is upregulated in prostate cancer, hormone-refractive disease, and prostate cancer metastases. Investigations using radioimmunoscintigraphy with the radiolabeled 7E11 antibody capromab pendetide have significantly improved sensitivity for prostate cancer detection compared with standard cross-sectional imaging, based on tissue confirmation of pathologic results. Over the past 5 years, significantly greater image resolution from improved camera technology and the use of co-registration to fuse functional and anatomic (computerized tomography and magnetic resonance imaging) images have dramatically enhanced prostate cancer localization. Outcomes data from several sources have spurred a resurgence in interest in this imaging modality.
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PMID:The emergence of radioimmunoscintigraphy for prostate cancer. 1702 23

Distinguishing aggressive prostate cancer from indolent disease represents an important clinical challenge, because current therapy may lead to overtreatment of men with limited disease. The prostate-specific membrane antigen (PSMA) is a membrane-bound glycoprotein that is highly restricted to the prostate. Previously, studies analyzing the expression of PSMA have found an up-regulation in correlation with prostate cancer, particularly in advanced cancer. This association is ideal for an application as a prognostic marker. In the current study, we characterized PSMA expression in a high-risk cohort and evaluated its potential use as predictive marker of prostate-specific antigen (PSA) recurrence. PSMA expression was analyzed by immunohistochemistry using tissue microarrays composed of tumor samples from 450 patients. Protein intensity was recorded using a semiautomated quantitative microscope system (ACIS II; Clarient Chromavision Medical Systems, San Juan Capistrano, CA). PSMA expression levels differed significantly (P < .001) between benign prostatic tissue, localized prostate cancer, and lymph node metastases. Dividing the cohort into high- and low-PSMA expressing cancers based on the median area of positive staining, we found that high PSMA levels were associated with significant increase of PSA recurrence (P = .004). This was independent of clinical parameters such as lymph node tumor burden (lymph node density, >20%; P < .001), extraprostatic extension (P = .017), seminal vesicle invasion (P < .001), and high Gleason score (8-10, P = .006). In a multivariate model, PSMA expression and metastases to pelvic lymph nodes were significantly associated with time to PSA recurrence (HR, 1.4; 95% confidence interval, 1.1-2.8, P = .017; and hazard ratio, 5; 95% confidence interval, 2.6-9.7, P < .001, respectively). In summary, PSMA is independently associated with PSA recurrence in a high-risk cohort and thus might provide insight into the additional use of adjuvant therapy. Validation on other cohorts is required.
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PMID:Prostate-specific membrane antigen expression as a predictor of prostate cancer progression. 1732 Jan 51

Antibody-conjugated iron oxide nanoparticles offer a specific and sensitive tool to enhance magnetic resonance (MR) images of both local and metastatic cancer. Prostate-specific membrane antigen (PSMA) is predominantly expressed on the neovasculature of solid tumors and on the surface of prostate cells, with enhanced expression following androgen deprivation therapy. Biotinylated anti-PSMA antibody was conjugated to streptavidin-labeled iron oxide nanoparticles and used in MR imaging and confocal laser scanning microscopic imaging studies using LNCaP prostate cancer cells. Labeled iron oxide nanoparticles are internalized by receptor-mediated endocytosis, which involves the formation of clathrin-coated vesicles. Endocytosed particles are not targeted to the Golgi apparatus for recycling but instead accumulate within lysosomes. In T(1)-weighted MR images, the signal enhancement owing to the magnetic particles was greater for cells with magnetic particles bound to the cell surface than for cells that internalized the particles. However, the location of the particles (surface vs internal) did not significantly alter their effect on T(2)-weighted images. Our findings indicate that targeting prostate cancer cells using PSMA offers a specific and sensitive technique for enhancing MR images.
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PMID:Targeting and cellular trafficking of magnetic nanoparticles for prostate cancer imaging. 1771 83

Standard systemic treatment of prostate cancer today is comprised of antihormonal and cytostatic agents. Vaccine therapy of prostate cancer is principally attractive because of the presence of tumor-associated antigens such as prostate-specific antigen (PSA), prostatic acid phosphatase (PAP), prostate-specific membrane antigen (PSMA), and others. Most prostate cancer vaccine trials have demonstrated some activation of the immune system, limited clinical success, and few adverse effects.One strategy to overcome the problem of limited clinical success of vaccine therapies in prostate cancer could be strict patient selection. The clinical course of patients with prostate cancer (even in those with PSA relapse following surgery or radiotherapy with curative intention, or those with metastatic disease) can vary significantly. In patients with organ-confined prostate cancer, the most promising immunotherapeutic approach would be an adjuvant therapy following surgery or radiotherapy. Patients with PSA relapse following surgery or radiotherapy could also benefit from immunotherapy because tumor burden is usually low. However, most patients in prostate cancer vaccine trials had metastatic hormone-refractory prostate cancer (HRPC). High tumor burden correlates with immune escape phenomena. Nevertheless, 2 years ago, it was demonstrated, for the first time, that a tumor vaccine can prolong survival compared with placebo in patients with HRPC. This was demonstrated with the vaccine sipuleucel-T (APC-8015; Provenge), a mixture of cells obtained from the patient's peripheral blood by leukapheresis followed by density centrifugation and exposition. The Biologics License Application for this vaccine was denied by the US FDA in mid 2007, however, because the trial had failed to reach the primary endpoint (prolongation of time to tumor progression). Nevertheless, clinical trials with sipuleucel-T are ongoing, and the approach still looks promising. Another interesting approach is a vaccine made from whole tumor cells: GVAX. This vaccine is presently being studied in phase III trials against, and in combination with, docetaxel. The results from these trials will become available in the near future. Besides the precise definition of the disease status of patients with prostate cancer, combinations of vaccine therapy with radiotherapy, chemotherapy, and/or hormonal therapy are approaches that look promising and deserve further investigation.
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PMID:Prostate cancer vaccines: current status and future potential. 1834 5

Prostate cancer is the most common non-cutaneous cancer of men in the United States and represents their second-leading cause of cancer-related death. Metastatic disease is largely resistant to conventional chemotherapies, and targeted therapies are urgently needed. Prostate-specific membrane antigen (PSMA) is a prototypical cell-surface marker of prostate cancer. PSMA is an integral, non-shed, type 2 membrane protein with abundant and nearly universal expression in prostate carcinoma, but has limited extra-prostatic expression. In addition, PSMA is expressed in the neovasculature of other solid tumors. These findings have spurred development of PSMA-targeted therapies for cancer, and first-generation products have entered clinical testing. Vaccine approaches have included recombinant protein, nucleic acid and cell-based strategies, and anti-PSMA immune responses have been demonstrated in the absence of significant toxicity. Therapy with drug-conjugated and radiolabeled antibodies has yielded objective clinical responses as measured by reductions in serum prostate-specific antigen and/or imageable tumor volume. However, responses were observed in a minor fraction of patients and at doses near the maximum tolerated dose. Overall, these initial studies have provided measured proof of concept for PSMA-based therapies, and second-generation antibody and vaccine products may hold the key to exploit PSMA for molecularly targeted therapy of prostate and other cancers.
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PMID:Clinical trials of cancer therapies targeting prostate-specific membrane antigen. 1847 4


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