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)

Our laboratory has developed two cellular models of human prostate cancer progression. The LNCaP prostate cancer progression model is based upon the well-known cellular interaction between human prostate or bone stromal cells and LNCaP cells in vivo. The marginally tumorigenic LNCaP cells acquired tumorigenic and metastatic potential upon cellular interaction with either prostate or bone fibroblasts. A subline termed C4-2 was observed to grow readily in castrated animals and acquired metastatic potential spreading from the primary tumor site to the lymph node, the seminal vesicles, and the axial skeleton, resulting in an intense osteoblastic reaction. The second model is ARCaP, where prostate cancer cells derived from the ascites fluid of a man with metastatic disease exhibited an Androgen- and estrogen-Repressed Prostate Cancer cell growth and tumor formation in either a hormone-deficient or a castrated environment. However, the growth of either the tumor cells in vitro or the tumors in vivo was suppressed by both estrogen and androgen. While the tumor cells expressed low levels of androgen receptor and prostate-specific antigen (PSA), they were highly metastatic when inoculated orthotopically. Distant metastases to a number of organs were detected, including the liver, lung, kidney, and bone. We have employed a human prostate cancer progression model as a system to study the efficacy of gene therapy. Results of the study show that whereas universal promoters, such as Cytomegalovirus (CMV) and Rous Sarcoma Virus (RSV) promoter-driven tumor suppressors (e.g. p53, p21, and p16), were effective in inhibiting prostate tumor growth, the advantages of driving the expression of therapeutic toxic genes using a tissue-specific promoter prostate-specific antigen (PSA) and a tumor--but not tissue-specific promoter, osteocalcin (OC), are preferred. In the case of the PSA promoter, we can achieve cell-kill in PSA-producing human prostate cancer cells. To circumvent the supporting role of bone stroma for prostate cancer epithelial growth, we have recently developed a novel concept where the expression of therapeutic toxic genes is driven by a tumor--but not a tissue-specific OC promoter. Osteocalcin-thymidine kinase (OC-TK) was found to efficiently eradicate the growth of osteosarcoma, prostate, and brain tumors both in vitro and in vivo. We observed that androgen-independent human prostate cancer cells lines expressed OC-TK at higher levels than androgen-dependent human prostate cancer cell lines. We have obtained data to suggest that Ad-OC-TK plus a pro-drug acyclovir (ACV) may be used as an effective therapy to treat prostate cancer bone metastasis in models where the growth of androgen-independent PC-3 and C4-2 tumors in the bone has occurred.
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PMID:Human prostate cancer progression models and therapeutic intervention. 943 28

Prostate cancer development and progression is driven by the accumulation of genetic changes, the nature of which remains incompletely understood To facilitate high-throughput analysis of molecular events taking place in primary, recurrent, and metastat prostate cancer, we constructed a tissue microarray containing small 0.6-mm cylindrical samples acquired from 371 formalin-fixed blocks, including benign prostatic hyperplasia (n = 32) and primary tumors (n = 223), as well as both locally recurrent tumors (n = 54) and metastases (n = 62) from patients with hormone-refractory disease. Fluorescence in situ hybridization (FISH) was applied to the analysis of consecutive tissue microarray sections with probes for five different genes. High-level (> or =3X) amplifications were very rare (<2%) in primary prostate cancers However, in metastases from patients with hormone-refractory disease, amplification of the androgen receptor gene was seen in 22%, MYC in 11%, and Cyclin-D1 in 5% of the cases. In specimens from locally recurrent tumors, the corresponding percentages were 23, 4, and 8%. ERBB2 and NMYC amplifications were never detected at any stage of prostate cancer progression. In conclusion, FISH to tissue microarray sections enables high-throughput analysis of genetic alterations contributing to cancer development and progression. Our results implicate a role for amplification of androgen receptor in hormonal therapy failure and that of MYC in the metastatic progression of human prostate cancer.
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PMID:Survey of gene amplifications during prostate cancer progression by high-throughout fluorescence in situ hybridization on tissue microarrays. 1002 66

Metastatic prostate cancer is a leading cause of cancer-related death in men. Although most patients will respond to androgen ablation as initial systemic therapy, nearly all patients will develop androgen-independent prostate cancer (AI CaP) and will succumb to the disease. Advances in molecular biology have demonstrated mutations in and persistent expression of the human androgen receptor in metastatic disease. Furthermore, recent evidence indicates that an apoptotic block through p53 mutations or bcl-2 overexpression may have a potential role in the poor responses seen with standard chemotherapy. Presently, the six general treatment options available for AI CaP are best supportive care, radiation therapy, radioisotopes, secondline hormonal therapy, chemotherapy (single agent or combination), and investigational therapies such as monoclonal antibodies, cyclin-dependent kinase inhibitors, matrix metalloproteinase inhibitors, and antiangiogenesis agents, among others. None of these modalities have produced durable remissions, although some have demonstrated palliative benefit. The next generation of clinical trials should not consist of futile hormonal manipulations or repetitive chemotherapy. Therapeutic strategies aimed at circumventing molecular blocks to cell death or targeting unique cancer molecules and genes will be more likely to improve quality of life and longevity. Furthermore, the aggressive use of palliative care will ensure effective caring for patients and the healing of families in the absence of cure.
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PMID:Treatment options in androgen-independent prostate cancer. 1007 98

A 31-year-old woman presented with multiple pulmonary leiomyomatous hamartoma (MPLH) with secondary ossification. She had a past history of parosteal osteosarcoma. The pulmonary lesions were composed of spindle-shaped cells arranged in interlacing fascicles, among which glands or duct-like spaces were scattered. As some lesions contained bony tissues, it was unclear whether or not the pulmonary lesions were metastases of parosteal osteosarcoma. However, the majority of spindle-shaped cells were positive for alpha-smooth muscle actin, including cells proliferating around the bony tissues. Clonality analysis using a target of human androgen receptor (HUMARA) gene disclosed that the pulmonary nodules were polyclonal. These findings do not indicate that the lesions were metastatic. We would like to emphasize that MPLH can show osseous metaplasia.
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PMID:Multiple pulmonary leiomyomatous hamartoma with secondary ossification. 1033 77

Androgen blockade is the mainstay of therapy in the clinical management of advanced prostate cancer. Recent progress on two fronts--the development of newer xenograft and transgenic models and a greater understanding of nuclear receptor signaling--has provided new insight into mechanisms of androgen-dependence in prostate cancer. This review centers on the concept that perturbations in androgen receptor signaling are likely to occur early in prostate cancer and play a critical role in progression to end stage hormone-refractory disease.
Cancer Metastasis Rev
PMID:Mechanistic concepts in androgen-dependence of prostate cancer. 1045 86

Androgens are essential for the development, growth, and maintenance of the prostate. They exert their effects via the intracellular androgen receptor (AR), which is a ligand-dependent transcription activator. As is the case with normal prostate development, primary prostatic cancers are largely dependent on androgens for growth and survival. Most patients respond favorably to androgen ablation and antiandrogen therapy, which has become a standard treatment of metastatic disease. However, virtually all patients will relapse with clinically defined androgen-independent cancer. This phenomenon raises the question of how cancer cells survive and grow in the low androgen environment? Two of the routes cells can take to adapt are (1) bypassing and (2) sensitizing the AR pathway. The vast numbers of AR abnormalities observed in prostate tumors from patients treated with hormonal therapy suggest that many cells sensitize or change the AR pathway. To continue to activate this pathway in a low androgen environment, cells can (1) mutate the AR to become promiscuously activated by different steroids, (2) amplify the AR, (3) activate the AR in a ligand-independent manner by growth factors and cytokines, or (4) amplify coactivators. Alternatively, prostate cancer cells that have lost AR expression must have bypassed the AR pathway. Activation of oncogenes and autocrine growth factor stimulation are two mechanisms that likely contribute to becoming completely androgen-independent. From all the studies on AR function in prostate cancer, it is clear that the AR plays an important role in cancer development and progression. Moreover, the AR pathway remains important in most cells from patients with clinically defined androgen-independent prostate cancer.
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PMID:The role of the androgen receptor in the development and progression of prostate cancer. 1048 83

We report a case of prostate cancer that presented initially as an intracranial tumor. Biopsy specimens of the prostate before endocrine treatment were nearly negative immunohistochemically for prostate-specific antigen and the androgen receptors. All metastases including those in the brain expressed neither androgen receptor nor prostate-specific antigen at the protein and mRNA levels. The tumor, which did not respond to the anti-androgen therapy, had an aggressive course. In this case, the androgen-independent growth and rapid progression might be associated with the initial loss of the antigen and androgen characteristics of the prostate.
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PMID:Loss of tissue immunoreactive androgen receptor in prostate cancer presenting initially as an intracranial tumor. 1059 3

Gastrinomas are neuroendocrine neoplasms that occur sporadically and in patients with multiple endocrine neoplasia type 1 (MEN1). In MEN1, multiple gastrinomas have been shown to arise by independent clonal events (Debelenko, et al., Cancer Res., 57: 2238-2243, 1997). The purpose of the present study was to analyze clonality in 20 sporadic gastrinomas from eight patients in whom the tumor was present in at least two separate sites. A combination of methods was used to assess clonality, including MEN1 gene mutation analysis, loss of heterozygosity analysis of the MEN1 locus, and analysis of X-chromosome inactivation at the human androgen receptor locus (human androgen receptor analysis). In three patients, a somantic MEN1 gene mutation was detected in the tumor. Identical mutations were found in other tumors at different sites within the same patients. Human androgen receptor analysis in three informative patients and loss of heterozygosity analysis in five patients revealed identical clonal patterns in the tumors from multiple sites in each patient. We conclude that sporadic gastrinomas at multiple sites are monoclonal and that MEN1 gene alterations in gastrinomas occur before the development of tumor metastases.
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PMID:Identical clonality of sporadic gastrinomas at multiple sites. 1064 53

We analyzed the frequency and relevance of mutations in the coding region of the androgen receptor (AR) in genomic DNA extracted from 137 specimens of prostate cancer. The specimens were obtained from the primary tumors of patients affected by stage B disease [15 nonmicrodissected (group 1A) and 84 microdissected (group 1B)] and from the metastatic deposits of individuals with stage D1 disease [8 nonmicrodissected (group 2A) and 30 microdissected (group 2B)] who had not undergone androgen ablation therapy. The study was conducted by PCR-single strand conformational polymorphism (SSCP) analysis of exons 2-8 in the four groups and direct sequence analysis of exon 1 in group 1B. As positive and negative controls, we used genomic DNA extracted from genital skin fibroblasts of patients affected by various forms of androgen resistance with known mutations in the AR. To control for genetic instability, PCR-SSCP analysis of exon 2 of the human progesterone receptor was carried out on each specimen. The overall number of mutations detected was 11 (8%). No mutations were detected in any of the 99 patients with stage B disease. Eleven mutations were detected in exons 2-8 in 8 of the 38 patients with stage D1 disease (all in group 2B). Simultaneous analysis of exon 2 of the progesterone receptor was carried out, and no SSCP changes were identified. These data suggest that AR mutations are rare and presumably do not play a role in the initial phase of prostatic carcinogenesis. The presence of a significant number of AR mutations in metastatic disease indicates that mutations of this molecule may play a role in the most advanced phases of the natural history of this disease, either by facilitating growth or acquisition of the metastatic phenotype.
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PMID:Androgen receptor mutations in prostate cancer. 1070 9

Currently available methods for treatment of human prostatic carcinoma aim to inactivate the androgen receptor (AR) by androgen deprivation or blockade with anti-androgens. Failure of endocrine therapy and tumor progression is characterized by androgen-independent growth despite high levels of AR expression in metastatic disease. We inhibited AR expression in LNCaP prostate tumor cells by using antisense AR oligodeoxynucleotides (ODNs) and explored whether antisense AR treatment would be conceivable as a therapy for advanced prostate cancer. Among the various AR antisense ODNs tested, a 15-base ODN targeting the CAG repeats encoding the poly-glutamine region of the AR (as750/15) was found to be most effective. Treatment of LNCaP cells with as750/15 reduced AR expression to approximately 2% within 24 hours compared with mock-treated controls. AR down-regulation resulted in significant cell growth inhibition, strongly reduced secretion of the androgen-regulated prostate-specific antigen, reduction of epidermal growth factor receptor expression, and an increase in apoptotic cells. Mis-sense and mismatched control ODNs had no or only slight effects. Antisense inhibition was also very efficient in LNCaP-abl cells, a subline established after long-term androgen ablation of LNCaP cells, resulting in inhibition of AR expression and cell proliferation that was similar to that seen for parental LNCaP cells. This study shows that inhibition of AR expression by antisense AR ODNs may be a promising new approach for treatment of advanced human prostate cancer.
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PMID:Inhibition of LncaP prostate cancer cells by means of androgen receptor antisense oligonucleotides. 1091 2


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