| 1. |
- Fowler, Christopher J., et al.
(author)
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Tumour epithelial expression levels of endocannabinoid markers modulate the value of endoglin-positive vascular density as a prognostic marker in prostate cancer
- 2013
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In: Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids. - : Elsevier BV. - 1388-1981 .- 1879-2618. ; 1831:10, s. 1579-1587
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Journal article (peer-reviewed)abstract
- Fatty acid amide hydrolase (FAAH) is responsible for the hydrolysis of the endogenous cannabinoid (CB) receptor ligand anandamide. Here we have investigated whether the expression levels of FAAH and CB1 receptors influence the prognostic value of markers of angiogenesis in prostate cancer. Data from a cohort of 419 patients who were diagnosed with prostate cancer at transurethral resection for lower urinary tract symptoms, of whom approximately 2/3 had been followed by expectancy, were used. Scores for the angiogenesis markers endoglin and von Willebrand factor (vWf), the endocannabinoid markers fatty acid amide hydrolase (FAAH) and cannabinoid CB1 receptors and the cell proliferation marker Ki-67 were available in the database. For the cases followed by expectancy, the prognostic value of endoglin was dependent upon the tumour epithelial FAAH immunoreactivity (FAAH-IR) and CB1IR scores, and the non-malignant epithelial FAAH-IR scores, but not the non-malignant CB1IR scores or the tumour blood vessel FAAH-IR scores. This dependency upon the tumour epithelial FAAH-IR or CB1IR scores was less apparent for vWf, and was not seen for Ki-67. Using an endoglin cut-off value of 10 positively stained vessels per core and a median split of tumour FAAH-IR, four groups could be generated, with 15 year of disease-specific survival (%) of 68 +/- 7 (low endoglin, low FAAH), 45 +/- 11 (high endoglin, low FAAH), 77 +/- 6 (low endoglin, high FAAH) and 21 +/- 10 (high endoglin, high FAAH). Thus, the cases with high endoglin and high FAAH scores have the poorest rate of disease-specific survival. At diagnosis, the number of cases with tumour stages 1a-1b relative to stages 2-4 was sensitive to the endoglin score in a manner dependent upon the tumour FAAH-IR. It is concluded that the prognostic value of endoglin as a marker of neovascularisation in prostate cancer can be influenced by the expression level of markers of the endocannabinoid system. This article is part of a Special Issue entitled Lipid Metabolism in Cancer.
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| 2. |
- Thors, Lina, 1981-, et al.
(author)
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Biochanin A acts as a peripheral inhibitor of fatty acid amide hydrolase
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Other publication (other academic/artistic)abstract
- Inhibitors of fatty acid amide hydrolase (FAAH), the enzyme primarily responsible for the metabolism of the endogenous cannabinoid (CB) receptor ligand anandamide, are effective in animal models of inflammatory, cancer, visceral and neuropathic pain. No peripherallyrestricted FAAH inhibitors have yet been reported. The isoflavones are a class of naturallyoccurring compounds that show little brain penetration, and two of these, genistein and daidzein, inhibit FAAH at low micromolar concentrations. Here, we report that the related isoflavone biochanin A inhibits the hydrolysis of 0.5 μM anandamide by mouse, rat and human FAAH with IC50 values of 1.8, 1.4, and 2.4 μM, respectively. The inhibition of rat FAAH by biochanin A was mixed type in nature, with Ki slope and Ki intercept values of 1.1 and 8.2 μM, respectively. Anandamide hydrolysis was also inhibited in intact basophilic leukaemia cells at sub- to low- micromolar concentrations. The compound did not interact to any major extent with CB1 or CB2 receptors. In vivo, biochanin A (10 mg/kg i.v.) did not increase brain anandamide concentrations, but produced a modest potentiation of the effects of 10 mg/kg i.v. anandamide in the tetrad test. In anaesthetized mice, URB597 (30 μg/paw) and biochanin A (100 μg/paw) both inhibited the spinal phosphorylation of extracellular receptor kinase produced by the intraplantar injection of formalin. The effects of both compounds were significantly reduced by the CB1 receptor antagonist/inverse agonist AM251 (30 μg/paw). It is concluded that biochanin A may be useful as a template for the design of novel, peripherally-acting FAAH inhibitors.
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| 3. |
- Thors, Lina, 1981-, et al.
(author)
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Characterization of anandamide retention in synthetic liposomes
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Other publication (other academic/artistic)abstract
- Anandamide (AEA) is an endogenous ligand for cannabinoid receptors. Prior to termination of signalling activity AEA has to move across the plasma membrane to the reach its intracellular hydrolytic enzyme. The mechanism underlying this transport is under considerable debate. In the present study, we have examined the properties of AEA retention using synthetic large unilamellar liposomes (LUVs). Retention of AEA in LUVs was saturable, time- and temperature-dependent. Preincubation of LUVs with inhibitors of AEA uptake and metabolism did not decrease the tritium retention. These results mimic the “initial” cellular uptake of AEA and indeed argue against the need of a specific membrane transporter protein.
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| 4. |
- Thors, Lina, et al.
(author)
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Effect of nitric oxide donors on membrane tritium accumulation of endocannabinoids and related endogenous lipids.
- 2009
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In: European Journal of Pharmacology. - : Elsevier BV. - 0014-2999 .- 1879-0712. ; 621:1-3, s. 10-18
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Journal article (peer-reviewed)abstract
- The endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) are metabolised by cells by hydrolysis to arachidonic acid followed by esterification into phospholipids. Here, we report that nitric oxide (NO) donors significantly increase the amount of tritium accumulated in the cell membranes of RBL2H3 rat basophilic cells, 3T3-L1 mouse fibroblast cells and b.End5 mouse brain endothelioma cells following incubation of the intact cells with AEA labelled in the arachidonate part of the molecule. Similar results were seen with 2-AG and with arachidonic acid, whilst the NO donors reduced the accumulation of tritium after incubation of RBL2H3 cells with AEA labelled in the ethanolamine part of the molecule. Pretreatment of intact cells with NO donors did not increase the activity of the enzyme mainly responsible for metabolism of AEA, fatty acid amide hydrolase (FAAH). Furthermore, inhibition of FAAH completely blocked the effect produced by NO donors in cells with a large FAAH component, suggesting that for AEA, the effects were downstream of the enzyme. These data raise the possibility that the cellular processing of endocannabinoids following its uptake can be regulated by nitric oxide.
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| 5. |
- Thors, Lina, 1981-, et al.
(author)
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Effect of nitric oxide donors on membrane tritium accumulation of endocannabinoids and related endogenous lipids
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Other publication (other academic/artistic)abstract
- Endocannabinoids refers to a group of lipids with the ability of binding the two known cannabinoid receptors and synthesized by hydrolysis of lipid precursors. But still is the processing of the endocannabinoid metabolites following degradation poorly understood. Using tritium labelled anandamide (AEA) we discovered that nitric oxide (NO) donors significantly increased the amount of tritium accumulated in the cell membranes of RBL2H3 rat basophilic cells, 3T3-L1 mouse fibroblast cells and b.End5 mouse brain endothelioma cells following incubation. In addition, utilizing AEA labelled in either the arachidonate or ethanolamine part of the molecule revealed that the effect of NO donors mainly involved the arachidonate part of the molecule. In enzyme studies, pretreatment of intact cells with NO donors did not increase the activity of the enzyme mainly responsible for metabolism of AEA, fatty acid amide hydrolase (FAAH). Furthermore, inhibition of FAAH completely diminished the effect produced by NO donors in cells with a large FAAH component, indicating that the effects were downstream of the enzyme. Similar results of the NO donors were also obtained when radiolabelled 2-arachidonoylglycerol (2-AG) was used. These data showed that the processing of endocannabinoid metabolites can be regulated by NO donors and may therefore be of importance in recycling lipid compounds to elevate the tissue levels.
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| 6. |
- Thors, Lina, et al.
(author)
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Fatty acid amide hydrolase in prostate cancer : association with disease severity and outcome, CB1 receptor expression and regulation by IL-4
- 2010
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In: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 5:8, s. e12275-
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Journal article (peer-reviewed)abstract
- Background Recent data have indicated that there may be a dysregulation of endocannabinoid metabolism in cancer. Here we have investigated the expression of the endocannabinoid metabolising enzyme fatty acid amide hydrolase (FAAH) in a well characterised tissue microarray from patients diagnosed with prostate cancer at transurethral resection for voiding problems. Methodology/Principal Findings FAAH immunoreactivity (FAAH-IR) was assessed in formalin-fixed paraffin-embedded non-malignant and tumour cores from 412 patients with prostate cancer. CB1 receptor immunoreactivity (CB1IR) scores were available for this dataset. FAAH-IR was seen in epithelial cells and blood vessel walls but not in the stroma. Tumour epithelial FAAH-IR was positively correlated with the disease severity at diagnosis (Gleason score, tumour stage, % of the specimen that contained tumour) for cases with mid-range CB1IR scores, but not for those with high CB1IR scores. For the 281 cases who only received palliative therapy at the end stages of the disease, a high tumour epithelial FAAH-IR was associated with a poor disease-specific survival. Multivariate Cox proportional-hazards regression analyses indicated that FAAH-IR gave additional prognostic information to that provided by CB1IR when a midrange, but not a high CB1IR cutoff value was used. Interleukin-4 (IL-4) receptor IR was found on tumour epithelial cells and incubation of prostate cancer PC-3 and R3327 AT1 cells with IL-4 increased their FAAH activity. Conclusions/Significance Tumour epithelial FAAH-IR is associated with prostate cancer severity and outcome at mid-range, but not high, CB1IR scores. The correlation with CB1IR in the tumour tissue may be related to a common local dysregulation by a component of the tumour microenvironment.
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| 7. |
- Thors, Lina, 1981-, et al.
(author)
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Inhibition of fatty acid amide hydrolase by kaempferol and related naturally occurring flavonoids
- 2008
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In: British Journal of Pharmacology. - : Wiley. - 0007-1188 .- 1476-5381. ; 155:2, s. 244-252
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Journal article (peer-reviewed)abstract
- BACKGROUND AND PURPOSE: Recent studies have demonstrated that the naturally occurring isoflavone compounds genistein and daidzein inhibit the hydrolysis of anandamide by fatty acid amide hydrolase (FAAH) in the low micromolar concentration range. The purpose of the present study was to determine whether this property is shared by flavonoids.EXPERIMENTAL APPROACH:The hydrolysis of anandamide in homogenates and intact cells was measured using the substrate labelled in the ethanolamine part of the molecule.KEY RESULTS: Twenty compounds were tested. Among the commonly occurring flavonoids, kaempferol was the most potent, inhibiting FAAH in a competitive manner with a K(i) value of 5 microM. Among flavonoids with a more restricted distribution in nature, the two most active toward FAAH were 7-hydroxyflavone (IC(50) value of 0.5-1 microM depending on the solvent used) and 3,7-dihydroxyflavone (IC(50) value 2.2 microM). All three compounds reduced the FAAH-dependent uptake of anandamide and its metabolism by intact RBL2H3 basophilic leukaemia cells.CONCLUSIONS AND IMPLICATIONS: Inhibition of FAAH is an additional in vitro biochemical property of flavonoids. Kaempferol, 7-hydroxyflavone and 3,7-dihydroxyflavone may be useful as templates for the synthesis of novel compounds, which target several systems that are involved in the control of inflammation and cancer.
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| 8. |
- Thors, Lina, 1981-, et al.
(author)
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Inhibition of the cellular uptake of anandamide by genistein and its analogue daidzein in cells with different levels of fatty acid amide hydrolase-driven uptake
- 2007
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In: British Journal of Pharmacology. - : Wiley. - 0007-1188 .- 1476-5381. ; 152:5, s. 744-750
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Journal article (peer-reviewed)abstract
- Background and purpose: Genistein, a tyrosine kinase inhibitor used to block caveolae dependent endocytosis, reduces the cellular uptake of anandamide in RBL2H3 basophilic leukaemia cells. However, genistein is also a competitive inhibitor of fatty acid amide hydrolase, the enzyme responsible for anandamide hydrolysis. Here we have investigated whether inhibition of fatty acid amide hydrolase rather than inhibition of endocytosis is the primary determinant of genistein actions upon anandamide uptake. Experimental approach: Cellular uptake of anandamide, labelled in the arachidonoyl part of the molecule was assessed in four different cell lines using a standard method. Fatty acid amide hydrolase activity in homogenates and intact cells was measured using anandamide labelled in the ethanolamine part of the molecule. Key results: The fatty acid amide hydrolase inhibitor URB597 inhibited anandamide uptake into RBL2H3 cells and R3327 AT-1 prostate cancer cells, but not into 3T3-L1 preadipocytes or PC-3 prostate cancer cells. An identical pattern was seen with genistein. The related compound daidzein inhibited anandamide hydrolysis in homogenates and intact cells, and reduced its uptake into RBL2H3 and R3327 AT-1, but not PC-3 cells. Anandamide hydrolysis by cell homogenates was in the order RBL2H3 4 R3327 AT-1 4 PC-3 E3T3-L1. Conclusions and implications: The ability of genistein to inhibit anandamide uptake is mimicked by daidzein (which does not affect tyrosine kinase), and is only seen in cells that show sensitivity to URB597. This indicates that blockade of fatty acid amide hydrolase is the primary determinant of the effects of genistein on cellular anandamide uptake.
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| 9. |
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| 10. |
- Thors, Lina, 1981-
(author)
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The cellular processing of the endocannabinoid anandamide and its pharmacological manipulation
- 2009
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Doctoral thesis (other academic/artistic)abstract
- Anandamide (arachidonoyl ethanolamide, AEA) and 2-arachidonoyl glycerol (2-AG) exert most of their actions by binding to cannabinoid receptors. The effects of the endocannabinoids are short-lived due to rapid cellular accumulation and metabolism, for AEA, primarily by the enzymes fatty acid amide hydrolase (FAAH). This has led to the hypothesis that by inhibition of the cellular processing of AEA, beneficial effects in conditions such as pain and inflammation can be enhanced. The overall aim of the present thesis has been to examine the mechanisms involved in the cellular processing of AEA and how they can be influenced pharmacologically by both synthetic natural compounds. Liposomes, artificial membranes, were used in paper I to study the membrane retention of AEA. The AEA retention mimicked the early properties of AEA accumulation, such as temperature-dependency and saturability. In paper II, FAAH was blocked by a selective inhibitor, URB597, and reduced the accumulation of AEA into RBL2H3 basophilic leukaemia cells by approximately half. Treating intact cells with the tyrosine kinase inhibitor genistein, an isoflavone found in soy plants and known to disrupt caveolae-related endocytosis, reduced the AEA accumulation by half, but in combination with URB597 no further decrease was seen. Further on, the effects of genistein upon uptake were secondary to inhibition of FAAH. The ability to inhibit the accumulation and metabolism of AEA was shared by several flavonoids (shown in paper III). In paper IV, the isoflavone biochanin A and URB597 had effects in vivo, in a model of persistent pain, effects decreased by the cannabinoid receptor 1 antagonist AM251. In paper VI, the cellular processing of the endocannabinoid metabolites following degradation was examined, a mechanism poorly understood. It was found that nitric oxide (NO) donors significantly increased the retention of tritium in cell membranes following incubation with either tritiated AEA or 2-AG. Further experiments revealed that the effect of NO donors mainly involves the arachidonate part of the molecules. Inhibition of FAAH completely reduced the effect of NO donors in cells with a large FAAH component, indicating that the effects were downstream of the enzyme. These results suggest that the cellular processing of endocannabinoids can be affected in a manner of different ways by pharmacological manipulation in vitro and that naturally occurring flavonoid compounds can interact with the endocannabinoid system.
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