Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0376358 (prostate cancer)
 59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The major lipoxygenation product derived from linoleic acid, 13-(S)-hydroxyoctadecadienoic acid (13-HODE), has been shown to be involved in cell proliferation and differentiation in a number of systems. Rapid detection of picogram amounts of this bioactive lipid in biological samples, however, has been hindered due to lack of immunological reagents. In the current report, we have used a polyclonal antibody specific for 13-(S)-HODE to detect this bioactive lipid for the first time in human prostate adenocarcinoma specimens (PCa) and the prostate cancer cell lines LNCaP and PC-3 by enzyme immunoassay. In addition, we have verified-the quantitation of 13-HODE by chiral-phase HPLC and examined the levels of lipoxygenase expression by Western, Northern, and RT-PCR analysis. Immunohistochemically detectable 13-HODE was observed in human PCa, whereas adjacent normal tissue showed no immunoreactivity. The presence of 15-lipoxygenase was evident by Western and RT-PCR analysis in both LNCaP and PC-3 cells, while Northern blot analysis showed the presence of 15-lipoxygenase message in LNCaP cells but failed to detect any 15-lipoxygenase message in PC-3 cells. In contrast, quantitation of 13-HODE by enzyme immunoassay and chiral-phase HPLC showed significant levels of the compound in PC-3 cells but minimal enzymatically produced 13-HODE in LNCaP cells. These data provide a link between linoleic acid metabolism and the development or progression of prostate cancer.
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PMID:Production of 13-hydroxyoctadecadienoic acid (13-HODE) by prostate tumors and cell lines. 936 45

Linoleic acid, an n-6 polyunsaturated fatty acid, is essential for normal mammary tissue development, at least in part because it provides the metabolic precursor required for the biosynthesis of key eicosanoids. A similar requirement applies to the growth of estrogen-independent but apparently not to estrogen-dependent rodent mammary and human breast carcinoma cells in vitro. By way of lipoxygenase products, n-6 fatty acids also regulate expression of the invasive phenotype. High-fat, linoleic acid-rich diets promote chemically induced rat mammary carcinogenesis, virally induced mouse mammary tumor development, and the growth and metastasis of estrogen-independent human breast cancer cells in athymic nude mice. In contrast, saturated fatty acids have no discernible effects on mammary carcinogenesis or progression. Most mechanistic studies have focused on the cyclooxygenase and lipoxygenase products of n-6 fatty acid metabolism, and support is accumulating for interactions between these eicosanoids and growth factors and oncogenes. The investigation of dietary fatty acids in prostate cancer is at an early stage and has been handicapped by a lack of satisfactory animal models. However, there are indications that the n-6 fatty acids perform functions in experimental prostate cancer progression similar to those described for breast cancer.
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PMID:Effects of dietary fatty acids on breast and prostate cancers: evidence from in vitro experiments and animal studies. 939 9

The widespread use of prostate-specific antigen (PSA) has revealed that radiation therapy cures adenocarcinoma of the prostate less frequently than previously believed. Biologic factors (such as the complex nature of this disease) and technical factors (geographic miss, inadequate dose to the tumor volume) affect the ability of radiation to effectively treat all patients with prostate cancer. To improve treatment outcome, patients with virulent forms of the disease must be identified. The use of prognostic markers (PSA, prostate-specific membrane antigen, prostate-specific antigen doubling time) and genetic markers (12 lipoxygenase, p53, bcl-2, ploidy) may aid in the development of treatments for these patients. Technical modifications have been made to increase the total dose delivered to the prostate and the accuracy of dose delivery. Brachytherapy, proton therapy and conformal radiation therapy have been used to increase the relative integral dose. Improved prostate targeting may be achieved with the use of fiducial markers, on-line portal imaging, and endorectal magnetic resonance imaging. High linear energy transfer radiation, radiosensitizers and altered fractionation have been used in an attempt to increase the biologic equivalent dose to the tumor. Lastly, hormonal therapy and chemotherapy have been shown to decrease tumor burden and improve local control. All of these methods may improve outcome in patients with adenocarcinoma of the prostate. However, further work must be completed to translate these methods into standards of care.
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PMID:A rational approach to the treatment of prostate cancer with radiation therapy: lessons for the future. 942 69

Increasing evidence suggests that lipoxygenase (LO)-catalysed metabolites have a profound influence on the development and progression of human cancers. Compared with normal tissues, significantly elevated levels of LO products have been found in breast tumours, colon cancers, lung, skin and prostate cancers, as well as in cells from patients with both acute and chronic leukaemias. LO-mediated products elicit diverse biological activities needed for neoplastic cell growth, influencing growth factor and transcription factor activation, oncogene induction, stimulation of tumour cell adhesion and regulation of apoptotic cell death. Agents that block LO catalytic activity may be effective in preventing cancer by interfering with signalling events needed for tumour growth. In the past ten years, pharmaceuticals agents that specifically inhibit the 5-LO metabolic pathway have been developed to treat inflammatory diseases such as asthma, arthritis and psoriasis. Some of these compounds possess anti-oxidant properties and may be effective in preventing cancer by blocking free radical-induced genetic damage or by preventing the metabolic activation of carcinogens. Other compounds may work by negatively modulating DNA synthesis. Pharmacological profiles of potential chemopreventive agents are compiled from enzyme assays, in vitro testing (e.g., cell proliferation inhibition in human cancer cells) and in vivo animal carcinogenesis models (e.g., N-methyl-N-nitrosourea-induced rat mammary cancer, benzo(a)pyrene-induced lung tumours in strain A/J mice and hormone-induced prostate tumours in rats). In this way, compounds are identified for chemoprevention trials in human subjects. Based on currently available data, it is expected that the prevention of lung and prostate cancer will be initially studied in human trials of LO inhibitors.
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PMID:Potential use of lipoxygenase inhibitors for cancer chemoprevention. 1106 Jul 97

Chemoprevention is the use of agents to slow progression of, reverse, or inhibit carcinogenesis thereby lowering the risk of developing invasive or clinically significant disease. With its long latency, high incidence and significant morbidity and mortality, prostate cancer is a relevant target for chemoprevention. Developing rational chemopreventive strategies for prostate cancer requires well-characterized agents, suitable cohorts, and reliable intermediate biomarkers of cancer. Chemopreventive agent requirements are experimental or epidemiologic data showing efficacy, safety on chronic administration, and a mechanistic rationale for activity. Current promising agents include antiandrogens and antiestrogens; steroid aromatase inhibitors; retinoids and their modulators; 5alpha-reductase inhibitors; vitamins D, E, and analogs; selenium compounds; carotenoids; soy isoflavones; dehydroepiandrostenedione and analogs; 2-difluoromethylornithine; lipoxygenase inhibitors; apoptosis inducers; and nonsteroidal anti-inflammatory drugs. Identifying biomarkers and validating them as surrogate endpoints for cancer incidence are critical for prostate chemoprevention trials. Potentially useful biomarkers for prostate chemoprevention are associated with histologic, proliferative, differentiation-related, biochemical, and genetic/regulatory features of prostatic disease. In that the prostate is not easily visualized, critical issues also include adequacy and consistency of tissue sampling. Various drugs for the chemoprevention of prostate cancer are now under evaluation in phase 1, 2, and 3 clinical trials. Cohort selection should be based on various patient characteristics (stage of the disease, previous cancers or premalignant lesions, or high risk factors) and should be conducted within the context of standard treatment.
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PMID:Agents, biomarkers, and cohorts for chemopreventive agent development in prostate cancer. 1129 94

The very fact that apoptosis and nonsteroidal anti-inflammatory drugs (NSAIDs) can be linked in the same title should tell you that something unusual is happening. The image of NSAIDs among physicians is certainly discordant with that associated with cancer treatment, which usually involves administration of drugs with serious or even life-threatening toxicity. In contrast, the drugs discussed in this review, including selective cyclooxygenase-2 inhibitors, lipoxygenase inhibitors, and novel NSAID derivatives (eg, sulindac sulfone and R-flurbiprofen), offer the promise of oral, nontoxic agents able to control the progression of established prostate cancer and possibly to prevent the development of prostate cancer de novo. NSAIDs were initially developed to suppress inflammation and pain by inhibiting the production of prostaglandin E2 and its metabolites. At first glance, the fact that NSAIDs are active against prostate cancer in laboratory and clinical studies might suggest that prostaglandins play a pivotal role in prostate cancer biology. However, the story is much more complex than that. Although cyclooxygenase-mediated production of prostaglandins appears to play an important role in the biology of prostate cancer, the NSAIDs and derivatives with promising activity against prostate cancer manifest several mechanisms of action that can include direct inhibition of eicosanoid formation, indirect inhibition of eicosanoid formation by inhibiting expression of enzymes involved in eicosanoid synthesis, or by interfering with the function of cyclic guanosine monophosphate.
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PMID:Proapoptotic anti-inflammatory drugs. 1129 99

15-Lipoxygenase 2 (15-LOX2) is a recently cloned human lipoxygenase that shows tissue-restricted expression in prostate, lung, skin, and cornea. The protein level and enzymatic activity of 15-LOX2 have been shown to be down-regulated in prostate cancers compared with normal and benign prostate tissues. The biological function of 15-LOX2 and the role of loss of 15-LOX2 expression in prostate tumorigenesis, however, remain unknown. We report the cloning and functional characterization of 15-LOX2 and its three splice variants (termed 15-LOX2sv-a, 15-LOX2sv-b, and 15-LOX2sv-c) from primary prostate epithelial cells. Western blotting with multiple primary prostate cell strains and prostate cancer cell lines reveals that the expression of 15-LOX2 is lost in all prostate cancer cell lines, accompanied by decreased enzymatic activity revealed by liquid chromatography/tandem mass spectrometry analyses. Further experiments show that the loss of 15-LOX2 expression results from transcriptional repression caused by mechanism(s) other than promoter hypermethylation or histone deacetylation. Subsequent functional studies indicate the following: 1) the 15-LOX2 product, 15(S)-hydroxyeicosatetraenoic acid, inhibits prostate cancer cell cycle progression; 2) 15-LOX2 expression in primary prostate epithelial cells is inversely correlated with cell cycle; and 3) restoration of 15-LOX2 expression in prostate cancer cells partially inhibits cell cycle progression. Taken together, these results suggest that 15-LOX2 could be a suppressor of prostate cancer development, which functions by restricting cell cycle progression.
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PMID:Evidence that arachidonate 15-lipoxygenase 2 is a negative cell cycle regulator in normal prostate epithelial cells. 1183 51

It is well established that fatty acid metabolites of cyclooxygenase, lipoxygenase (LOX), and cytochrome P450 are implicated in essential aspects of cellular signaling including the induction of programmed cell death. Here we review the roles of enzymatic and non-enzymatic products of polyunsaturated fatty acids in controlling cell growth and apoptosis. Also, the spontaneous oxidation of polyunsaturated fatty acids yields reactive aldehydes and other products of lipid peroxidation that are potentially toxic to cells and may also signal apoptosis. Significant conflicting data in terms of the role of LOX enzymes are highlighted, prompting a re-evaluation of the relationship between LOX and prostate cancer cell survival. We include new data showing that LNCaP, PC3, and Du145 cells express much lower levels of 5-LOX mRNA and protein compared with normal prostate epithelial cells (NHP2) and primary prostate carcinoma cells (TP1). Although the 5-LOX activating protein inhibitor MK886 killed these cells, another 5-LOX inhibitor AA861 hardly showed any effect. These observations suggest that 5-LOX is unlikely to be a prostate cancer cell survival factor, implying that the mechanisms by which LOX inhibitors induce apoptosis are more complex than expected. This review also suggests several mechanisms involving peroxisome proliferator activated receptor activation, BCL proteins, thiol regulation, and mitochondrial and kinase signaling by which cell death may be produced in response to changes in non-esterified and non-protein bound fatty acid levels. Overall, this review provides a context within which the effects of fatty acids and fatty acid oxidation products on signal transduction pathways, particularly those involved in apoptosis, can be considered in terms of their overall importance relative to the much better studied protein or peptide signaling factors.
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PMID:Fatty acid oxidation and signaling in apoptosis. 1203 33

We have investigated the mitochondrial and cellular effects of the lipoxygenase inhibitor MK886. Low concentrations (1 microM) of MK886 selectively sensitized the permeability transition pore (PTP) to opening, whereas higher concentrations of MK886 (10 microM) caused depolarization through combination of an ionophoretic effect with inhibition of respiration. MK886 killed prostate cancer PC3 cells only at the higher, toxic concentration (10 microM), whereas the lower concentration (1 microM) had no major effect on cell survival. However, 1 microM MK886 alone demonstrably induced PTP-dependent mitochondrial dysfunction; and it caused cell death through the mitochondrial pathway when it was used in combination with the cyclooxygenase inhibitor, indomethacin, which had no effects per se. Treatment with 1 microM MK886 plus indomethacin sensitized cells to killing by exogenous arachidonic acid, which induces PTP opening and cytochrome c release (Scorrano, L., Penzo, D., Petronilli, V., Pagano, F., and Bernardi, P. (2001) J. Biol. Chem. 276, 12035-12040). Combination of MK886 and cyclooxygenase inhibitors may represent a viable therapeutic strategy to force cell death through the mitochondrial pathway. This approach should be specifically useful to kill cells possessing a high flux of arachidonic acid and its metabolites like prostate and colon cancer cells.
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PMID:Mitochondria are direct targets of the lipoxygenase inhibitor MK886. A strategy for cell killing by combined treatment with MK886 and cyclooxygenase inhibitors. 1208 72

Metabolism of arachidonic acid through cyclooxygenase, lipoxygenase, or P450 epoxygenase pathways leads to the formation of various bioactive eicosanoids. In this review, we discuss alterations in expression pattern of eicosanoid-generating enzymes found during prostate tumor progression and expound upon their involvement in tumor cell proliferation, apoptosis, motility, and tumor angiogenesis. The expression of cyclooxygenase-2, 12-lipoxygenase, and 15-lipoxygenase-1 are up-regulated during prostate cancer progression. It has been demonstrated that inhibitors of cyclooxygenase-2, 5-lipoxygenase and 12-lipoxygenase cause tumor cell apoptosis, reduce tumor cell motility and invasiveness, or decrease tumor angiogenesis and growth. The eicosanoid product of 12-lipoxygenase, 12(S)-hydroeicosatetraenoic acid, is found to activate Erkl/2 kinases in LNCaP cells and PKCalpha in rat prostate AT2.1 tumor cells. Overexpression of 12-lipoxygenase and 15-lipoxygenase-1 in prostate cancer cells stimulate prostate tumor angiogenesis and growth, suggesting a facilitative role for 12-lipoxygenase and 15-lipoxygenase-1 in prostate tumor progression. The expression of 15-lipoxygenase-2 is found frequently to be lost during the initiation and progression of prostate tumors. 15(S)-hydroxyeicosatetraenoic acid, the product of 15-lipoxygenase-2, inhibits proliferation and causes apoptosis in human prostate cancer cells, suggesting an inhibitory role for 15-lipoxygenase-2 in prostate tumor progression. The regulation of prostate cancer progression by eicosanoids, in either positive or negative ways, provides an exciting possibility for management of this disease.
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PMID:Role of eicosanoids in prostate cancer progression. 1208 62


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