Lipid signaling is dysregulated in many diseases with vascular pathology, including cancer, diabetic retinopathy, retinopathy of prematurity, and age-related macular degeneration. We have previously demonstrated that diets enriched in ω-3 polyunsaturated fatty acids (PUFAs) effectively reduce pathological retinal neovascularization in a mouse model of oxygen-induced retinopathy, in part through metabolic products that suppress microglialderived tumor necrosis factor–α. To better understand the protective effects of ω-3 PUFAs, we examined the relative importance of major lipid metabolic pathways and their products in contributing to this effect. ω-3 PUFA diets were fed to four lines of mice deficient in each key lipid-processing enzyme (cyclooxygenase 1 or 2, or lipoxygenase 5 or 12/15), retinopathy was induced by oxygen exposure; only loss of 5-lipoxygenase (5-LOX) abrogated the protection against retinopathy of dietary ω-3 PUFAs. This protective effect was due to 5-LOX oxidation of the ω-3 PUFA lipid docosahexaenoic acid to 4-hydroxy-docosahexaenoic acid (4-HDHA). 4-HDHA directly inhibited endothelial cell proliferation and sprouting angiogenesis via peroxisome proliferator–activated receptor γ (PPARγ), independent of 4-HDHA’s anti-inflammatory effects. Our study suggests that ω-3 PUFAs may be profitably used as an alternative or supplement to current anti–vascular endothelial growth factor (VEGF) treatment for proliferative retinopathy and points to the therapeutic potential of ω-3 PUFAs and metabolites in other diseases of vasoproliferation. It also suggests that cyclooxygenase inhibitors such as aspirin and ibuprofen (but not lipoxygenase inhibitors such as zileuton) might be used without losing the beneficial effect of dietary ω-3 PUFA.

The inflammatory tumor microenvironment (TME) has many roles in tumor progression and metastasis, including creation of a hypoxic environment, increased angiogenesis and invasion, changes in expression of microRNAs (miRNAs) and an increase in a stem cell phenotype. Each of these has an impact on epithelial mesenchymal transition (EMT), particularly through the downregulation of E-cadherin. Here we review seminal work and recent findings linking the role of inflammation in the TME, EMT and lung cancer initiation, progression and metastasis.Finally, we discuss the potential of targeting aspects of inflammation and EMT in cancer prevention and treatment.

Liclican EL, McGiff JC, Falck JR, Carroll MA. Failure to upregulate the adenosine2A receptor-epoxyeicosatrienoic acid pathway contributes to the development of hypertension in Dahl saltsensitive rats. Am J Physiol Renal Physiol 295: F1696 -F1704, 2008. First published October 1, 2008 doi:10.1152/ajprenal.90502.2008.-Adenosine-activated renovascular dilatation in Sprague-Dawley (SD) rats is mediated by stimulating adenosine2A receptors (A2AR), which is linked to epoxyeicosatrienoic acid (EET) synthesis. The A2AR-EET pathway is upregulated by high salt (HS) intake in normotensive SD rats. Because this pathway is antipressor, we examined the role of the A2AR-EET pathway in Dahl salt-sensitive (SS) rats. Male Dahl salt-resistant (SR) and SS rats were fed either HS (8.0% NaCl) or normal salt (NS; 0.4% NaCl) diet for 7 days. On day 8, isolated kidneys were perfused with Krebs-Henseleit buffer containing indomethacin and N G -nitro-L-arginine methyl ester and preconstricted with phenylephrine. Bolus injections of the stable adenosine analog 2-chloroadenosine (2-CA; 0.1-20 g) elicited dose-dependent dilation in both Dahl SR and SS rats. Dahl SR rats fed a HS diet demonstrated a greater renal vasodilator response to 10 g of 2-CA, as measured by the reduction in renal perfusion pressure, than that of Dahl SR rats fed a NS diet (Ϫ104 Ϯ 6 vs. Ϫ77 Ϯ 7 mmHg, respectively; P Ͻ 0.05). In contrast, Dahl SS rats did not exhibit a difference in the vasodilator response to 2-CA whether fed NS or HS diet (96 Ϯ 6 vs. 104 Ϯ 13 mmHg in NS-and HS-fed rats, respectively). In Dahl SR but not Dahl SS rats, HS intake significantly increased purine flux, augmented the protein expression of A2AR and the cytochrome P-450 2C23 and 2C11 epoxygenases, and elevated the renal efflux of EETs. Thus the Dahl SR rat is able to respond to HS intake by recruiting EET formation, whereas the Dahl SS rat appears to have exhausted its ability to increase EET synthesis above the levels observed on NS intake, and this inability of Dahl SS rats to upregulate the A 2A R-EET pathway in response to salt loading may contribute to the development of salt-sensitive hypertension. epoxyeicosatrienoic acids; kidney; salt-sensitive hypertension SALT SENSITIVITY, as defined by blood pressure elevation in response to a dietary salt load, is not only a causative factor for a subgroup of humans with essential hypertension but also has been reported to be an independent cardiovascular risk factor in patients with hypertension (32). Therefore, understanding the mechanisms that contribute to the development of salt sensitivity and identifying potential therapeutic targets for the management of salt-sensitive hypertension should provide novel approaches to treat elevated blood pressure. Cytochrome P-450 (CYP) epoxygenases play a critical role in moderating salt sensitivity by producing epoxyeicosatrienoic acids (EETs). Capdevila and colleagues (5, 28) established the importance of EETs in antagonizing the pressor effects of high salt (HS) intake. Blood pressure did not increase...

450 (CYP)-dependent epoxyeicosatrienoic acids (EETs) dilate rat preglomerular microvessels when adenosine 2A receptors (A2AR) are stimulated. As high salt (HS) intake increases epoxygenase activity and adenosine levels, we hypothesized that renal adenosine responses would be greater in HS-fed rats. Male Sprague-Dawley rats were fed either HS (4.0% NaCl) or normal salt (NS; 0.4% NaCl) diet. On day 8, isolated kidneys were perfused with Krebs' buffer containing indomethacin (10 M) and L-NAME (200 M) and preconstricted to ϳ150 mmHg with infusion of phenylephrine (10 Ϫ7 M). Renal effluents were extracted for analysis of eicosanoids by gas chromatography-mass spectrometry. Bolus injections of the stable adenosine analog 2-chloroadenosine (2-CA; 0.1-10 g) resulted in dose-dependent dilation; at 10 g, perfusion pressure (PP) was lowered to a greater extent in the kidneys of HS rats compared with NS rats (Ϫ60 Ϯ 4 vs. Ϫ31 Ϯ 8 mmHg; P Ͻ 0.05) and the area of response was increased (27 Ϯ 6 vs. 9 Ϯ 4 mm 2 ; P Ͻ 0.05), as was EET release (132 Ϯ 23 vs. 38 Ϯ 18 ng; P Ͻ 0.05). HS treatment increased A2AR and CYP2C23 protein expression. A selective epoxygenase inhibitor, MS-PPOH (12 M), significantly reduced the response to 2-CA in HS rats; PP, area of response, and EET release decreased by 40, 70, and 81%, respectively, whereas lesser changes were evident in NS kidneys. Thus the greater vasodilator response to 2-CA seen in kidneys obtained from HS-fed rats was mediated by increased EET release. As EETs are renal vasodilator and natriuretic eicosanoids, interactions between adenosine and EETs may contribute to the adaptive response to HS intake. adenosine receptors; cytochrome P-450

These findings place the corneal PGE(2) circuit as an endogenous mediator of inflammatory neovascularization rather than general inflammation and demonstrate that chronic inflammation selectively regulates this circuit at the level of biosynthetic enzyme and receptor expression.

Abstract-Adenosine-induced renovasodilation in Dahl rats is mediated via activation of adenosine 2A receptors (A 2A Rs) and stimulation of epoxyeicosatrienoic acid (EET) synthesis. Unlike Dahl salt-resistant rats, salt-sensitive rats exhibit an inability to upregulate the A 2A R-EET pathway with salt loading; therefore, we examined the effect of in vivo inhibition of the A 2A R-EET pathway on blood pressure and the natriuretic response to salt-loading in Dahl salt-resistant rats. N-Methylsulfonyl-6-(2-propargyloxyphenyl)hexanamide (MS-PPOH; 20 mg/kg per day), an epoxygenase inhibitor, or ZM241385 (ZM; 5 mg/kg per day), an A 2A R antagonist, was given daily as an IV bolus dose for 3 days before and after placing rats on high salt intake (2% saline). After 3 days of high salt, systolic blood pressure per 24 hours increased from 108Ϯ2 mm Hg to 136Ϯ5 mm Hg and 140Ϯ4 mm Hg when treated with MS-PPOH or ZM, respectively (PϽ0.001). Plasma levels of EETs and dihydroxyeicosatrienoic acids during salt loading and MS-PPOH (29.3Ϯ1.8 ng/mL) or ZM treatment (9.8Ϯ0.5 ng/mL) did not increase to the same extent as in vehicle-treated rats (59.4Ϯ1.7 ng/mL; PϽ0.001), and renal levels of EETsϩdihydroxyeicosatrienoic acids were 2-fold lower with MS-PPOH or ZM treatment. On day 3 of the high salt intake, MS-PPOH-and ZM-treated rats exhibited a positive Na ϩ balance, and plasma Na ϩ levels were significantly increased (163.3Ϯ1.2 and 158.1Ϯ4.5 mEq/L, respectively) compared with vehicle-treated rats (142.1Ϯ1 mEq/L), reflecting a diminished natriuretic capacity. These data support a role for the A 2A R-EET pathway in the adaptive natriuretic response to modulate blood pressure during salt loading.

Lung cancer is the leading cause of cancer-related mortality in the United States. Despite a strong correlation between cigarette smoking and the onset of lung cancer, the prevalence of smoking still remains high. Strategies to eliminate cigarette smoking have led to the emergence of new tobacco-related products as alternatives for cigarette smoking or tools for smoking cessation. The electronic cigarette (ECIG) is a battery-powered electronic nicotine delivery system (ENDS) designed to deliver nicotine without combusting tobacco. Since nicotine is widely considered the addictive component in tobacco with limited ability to initiate cancer, ECIGs have been advertised to be a safer alternative to tobacco cigarettes (TCIGs). However, the toxicity and potential carcinogenicity of ECIGs have not previously been evaluated. In this study, we assess the impact of ECIG exposure on the carcinogenic potential of immortalized human bronchial epithelial cells on a background of silenced p53 and activated KRAS (H3mut-P53/KRAS). This model is utilized because p53 and KRAS mutations are often observed in the airway of current and former smokers at risk for lung cancer. The epithelial cells were exposed to both a low and high concentration of nicotine in the ECIG vapor- or TCIG smoke-conditioned media. The lower nicotine concentration was selected to mimic the average plasma nicotine levels in ENDS users and did not demonstrate toxic or anti-proliferative effects on the cells. The higher concentration was chosen to represent the anticipated nicotine levels to which the epithelial cells of smokers are actually exposed. In anchorage independent growth assays, the in vitro correlate of malignant transformation, we found enhanced colony growth in the H3mut-P53/KRAS cells following a 10-day treatment with the high nicotine ECIG- and TCIG-conditioned media compared to the untreated and low nicotine treatment groups. We next assessed the effect of ECIG and TCIG exposure on cell invasion using a three-dimensional air-liquid interface (ALI) model. At baseline, H3mut-P53/KRAS cells exhibit invasive behavior in the ALI model, due to the downstream effects of P53 silencing and KRAS activation. Treatment of H3mut-P53/KRAS cells with low nicotine ECIG- and TCIG-conditioned media did not further enhance the degree of invasion observed in the untreated group. We will next examine the effects of high nicotine conditioned media on cell invasion. Finally, gene expression studies show 263 differentially expressed genes following in vitro exposure to ECIG-conditioned media for 96hrs. The high nicotine ECIG-conditioned media induced a gene expression pattern similar to TCIG- conditioned media and whole cigarette smoke exposure in the H3mut-P53/KRAS cells. Preliminary analyses indicate the observed ECIG-specific gene expression changes were concordantly changed following TCIG-conditioned media exposure. We will next compare the ECIG-induced gene expression signature to carcinogenicity-related gene signatures established in previous and ongoing clinical investigations and test ECIG-altered candidate genes for their ability to drive the malignant transformation of airway epithelial cells. These studies will determine the impact of ECIG exposure on lung carcinogenicity and provide needed scientific guidance to the FDA regarding the physiologic effects of ECIGs. These studies were supported by funding from the following: NIH/NCI #U01CA152751 (SMD, TCW), NCI #U01CA152751-S1 (SMD, TCW, SJP), NCI #U01CA152751-AS (SMD, KK), NCI #T32-CA009120-36 (SMD, SJP, PCP), NIH/NHLBI #T32HL072752 (SMD, EL), University of California Tobacco-Related Disease Research Program (TRDRP) #18FT-0060 (TCW), TRDRP #20KT-0055 (TCW), Lung Cancer SPORE P50CA70907 (JDM, JEL) Citation Format: Stacy J. Park, Tonya C. Walser, Catalina Perdomo, Teresa Wang, Paul C. Pagano, Elvira L. Liclican, Kostyantyn Krysan, Jill E. Larsen, John D. Minna, Marc E. Lenburg, Avrum Spira, Steven M. Dubinett. The effect of e-cigarette exposure on airway epithelial cell gene expression and transformation. [abstract]. In: Proceedings of the AACR-IASLC Joint Conference on Molecular Origins of Lung Cancer; 2014 Jan 6-9; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2014;20(2Suppl):Abstract nr B16.

Lipid autacoids have well-established key roles in physiology and pathophysiology. Eicosanoids derived from ω-6 arachidonic acid (AA) have long been recognized for their roles in cardiovascular and renal functions, and vascular tone, as well as regulating inflammatory and immune functions. It is now appreciated that AA is a substrate for generating lipid mediators with anti-inflammatory and proresolving properties, namely lipoxins (i.e., LXA4), which are an integral component for the successful execution of beneficial and essential acute inflammatory responses. In addition to AA, the ω-3 polyunsaturated fatty acids (PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) also serve as substrates to generate potent and protective autacoids, such as resolvins and neuroprotectin (i.e., NPD1), respectively. These ω-3–derived signals may mediate the remarkable protective action of essential dietary ω-3 PUFAs. Formation and bioactivity of lipid mediators in the eye are relatively unexplored and of considerable interest, as the eye contains highly specialized tissues, including the transparent avascular and immune-privileged cornea, and the neuro-retina. A rapidly emerging field has identified key biosynthetic enzymes, receptors, and temporally defined endogenous formation of ω-3– and ω-6–derived protective lipid circuits in the eye. Protective endogenous roles of LXA4 and NPD1 have been established utilizing lipidomic analysis, knockout mice, and pharmacological, genetic, and dietary manipulation, providing compelling evidence that these intrinsic lipid autacoid circuits play essential roles in restraining inflammation, promoting wound healing, inhibiting pathological angiogenesis, and providing neuroprotection in the delicate visual axis.