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PDF file - 44K, Supplementary Table S2. Primer sequences for RT-PCR.

PDF file - 61K, Supplementary Figure S2. Inhibition of carcinogen-initiated (DEN), HFD-promoted glucose intolerance by APO10LA. Glucose tolerance test was conducted on 6-8 mice/group and calculated for AUC.

PDF file - 69K, The primer sequences for quantitative real-time PCR

PDF file - 30K, Supplementary Table S1. High-fat diet composition.

Supplementary Figure S1. Reduction of mRNA expressions of α7-nachr by BCX supplementation, not α3-, α5-, and β4-nachr, was associated with lung tumor multiplicity. Upper panel: The statistically significant correlation between lung tumor multiplicity (tumor number) and the expression of nachr-α7 mRNA (P = 0.03, r = 0.394, Pearson's correlation) and α7-nAChR protein (P < 0.01, r = 0.355, Pearson's correlation). Bottom panel: There were no significant differences in the nachr-α3, nachr-α5, and nachr-β4 mRNA levels among all the groups. The mRNA levels were measured with quantitative reverse transcription polymerase chain reaction (qRT-PCR) and were normalized to the levels of GAPDH mRNA levels. The columns represent the mean {plus minus} sem. Abbreviation: BCX(1): β-cryptoxanthin 1 mg/kg diet; BCX(10): β-cryptoxanthin 10 mg/kg diet; NNK: 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone. Supplementary Figure S2. BCX supplementation was associated with reduced early growth response-1 (Egr1) mRNA in the NNK-treated mice. The mRNA levels of egr1 were measured with quantitative reverse transcription polymerase chain reaction (qRT-PCR) and were normalized to the levels of GAPDH mRNA levels. The columns represent the mean {plus minus} sem. * P = 0.04. Dotted lines indicated significant decreasing levels in a BCX-dose dependent manner (P-linear trend = 0.05). Abbreviation: BCX (1): β-cryptoxanthin 1 mg/kg diet; BCX (10): β-cryptoxanthin 10 mg/kg diet; egr1: early growth response-1; NNK: 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone. Supplementary Figure S3. PI3K downstream Rac1 and ARF6 contribute to lamellipodia suppression by BCX. BEAS-2B cells were transfected with wild type Rac1 or ARF6. Then cells were treated with BCX (1.0, 2.0, 4.0 μM) or MG624 (1.0 μM) for 12 hr. Cells were stained with TRITC-labeled phalloidin and analyzed using fluorescent microscopy. The representative fluorescent images are shown (A, the lamellipodia are indicated by arrowheads). The number of cells with significant lamellipodia was counted in five random fields (C). The representative fluorescent images of BEAS-2B cells were transfected with Rac1-Q61L or ARF6-Q67L are shown (B, the lamellipodia are indicated by arrowheads). The number of cells with significant lamellipodia was counted in five random fields (D). Results of Scratch wound are displayed in (E). *P = 0.04, **P = 0.01 compared with control group.

Despite the consistent association between a higher intake of the provitamin A carotenoid β-cryptoxanthin (BCX) and a lower risk of lung cancer among smokers, potential mechanisms supporting BCX as a chemopreventive agent are needed. We first examined the effects of BCX on 4-[methyl nitrosamino]-1-[3-pyridyl]-1-butanone (NNK)-induced lung tumorigenesis in A/J mice. BCX supplementation was given daily to the mice starting 2 weeks prior to the injection of NNK and continued 16 weeks after NNK injection. BCX supplementation resulted in a dose-dependent increase of BCX concentration in both serum and lungs of the mice without a significant alteration of vitamin A (retinol and retinyl palmitate) concentration. BCX significantly reduced the multiplicity of the NNK-induced lung tumor by 52% to 63% compared with the NNK-treated mice without BCX supplementation. The protective effect of BCX in the lungs was associated with reductions of both mRNA and protein of the homopentameric neuronal nicotinic acetylcholine receptor α7 (α7-nAChR), which has been implicated in lung tumorigenesis. We then conducted an in vitro cell culture study and found that BCX treatment suppressed α7-nAChR expression and inhibited the migration and invasion of α7-nAChR-positive lung cancer cells but not in cells lacking α7-nAChR. The activities of BCX were significantly attenuated by activators of α7-nAChR/PI3K signaling or by overexpression of constitutively active PI3K. Collectively, the results suggest that BCX inhibits lung tumorigenesis and cancer cell motility through the downregulation of α7-nAChR/PI3K signaling, independent of its provitamin A activity. Therefore, BCX can be used as a chemopreventive agent or a chemotherapeutic compound against lung cancer. Cancer Prev Res; 9(11); 875–86. ©2016 AACR.

Obesity is associated with increased risk in hepatocellular carcinoma (HCC) development and mortality. An important disease control strategy is the prevention of obesity-related hepatic inflammation and tumorigenesis by dietary means. Here, we report that apo-10′-lycopenoic acid (APO10LA), a cleavage metabolite of lycopene at its 9′,10′-double bond by carotene-9′,10′-oxygenase, functions as an effective chemopreventative agent against hepatic tumorigenesis and inflammation. APO10LA treatment on human liver THLE-2 and HuH7 cells dose dependently inhibited cell growth and upregulated sirtuin 1 (SIRT1), a NAD+-dependent protein deacetylase that may suppress hepatic carcinogenesis. This observed SIRT1 induction was associated with decreased cyclin D1 protein, increased cyclin-dependent kinase inhibitor p21 protein expression, and induced apoptosis. APO10LA supplementation (10 mg/kg diet) for 24 weeks significantly reduced diethylnitrosamine-initiated, high fat diet (HFD)–promoted hepatic tumorigenesis (50% reduction in tumor multiplicity; 65% in volume) and lung tumor incidence (85% reduction) in C57Bl/6J mice. The chemopreventative effects of APO10LA were associated with increased hepatic SIRT1 protein and deacetylation of SIRT1 targets, as well as with decreased caspase-1 activation and SIRT1 protein cleavage. APO10LA supplementation in diet improved glucose intolerance and reduced hepatic inflammation [decreased inflammatory foci, TNFα, interleukin (IL)-6, NF-κB p65 protein expression, and STAT3 activation] in HFD-fed mice. Furthermore, APO10LA suppressed Akt activation, cyclin D1 gene, and protein expression and promoted PARP protein cleavage in transformed cells within liver tumors. Taken together, these data indicate that APO10LA can effectively inhibit HFD-promoted hepatic tumorigenesis by stimulating SIRT1 signaling while reducing hepatic inflammation. Cancer Prev Res; 6(12); 1304–16. ©2013 AACR.

PDF file - 48K, Supplementary Figure S1. Chemical structure of lycopene, APO10LA, acyclic retinoic acid and all-trans retinoic acid.

PDF file - 54K

β-Carotene-15, 15'-oxygenase (BCO1) and β-carotene-9', 10'-oxygenase (BCO2) are essential enzymes in carotenoid metabolism. While BCO1/BCO2 polymorphisms have been associated with alterations to human and animal carotenoid levels, experimental studies have suggested that BCO1 and BCO2 may have specific physiological functions beyond the cleavage of carotenoids. In the present study, we investigated the effect of ablation of both BCO1/BCO2 in the development of non-alcoholic fatty liver disease (NAFLD) and its underlying molecular mechanism(s). BCO1/BCO2 double knock out (DKO) mice developed hepatic steatosis (8/8) and had significantly higher levels of hepatic and plasma triglyceride and total cholesterol compared to WT (0/8). Hepatic changes in the BCO1/BCO2 DKO mice were associated with significant: 1) increases in lipogenesis markers, and decreases in fatty acid β-oxidation markers; 2) upregulation of cholesterol metabolism markers; 3) alterations to microRNAs related to TG accumulation and cholesterol metabolism; 4) increases in an hepatic oxidative stress marker (HO-1) but decreases in anti-oxidant enzymes; and 5) decreases in farnesoid X receptor (FXR), small heterodimer partner (SHP), and sirtuin 1 (SIRT1). The present study provided novel experimental evidence that BCO1 and BCO2 could play a significant role in maintaining normal hepatic lipid and cholesterol homeostasis, potentially through the regulation of the FXR/miR-34a/SIRT1 pathway.

Scope We have previously shown that apo-10’-lycopenoic acid (ALA), a derivative of lycopene through cleavage by carotene-9’,10’-oxygenase, inhibits tumor progression and metastasis in both liver and lung cancer animal models. The underlying mechanism remains unknown. We hypothesized that ALA inhibits cancer cell motility and angiogenesis by up-regulating peroxisome proliferator-activated receptor γ (PPARγ) which is involved in controlling angiogenesis, tumor progression and metastasis. Methods and results ALA treatment, in dose-dependent manner, was effective at inhibiting migration and invasion of liver and lung cancer cells (HuH7 and A549) in both Transwell and wound-healing models, as well as suppressing actin remodeling and ruffling/lamellipodia formation in HuH7 and immortalized lung BEAS-2B cells. ALA treatment resulted in suppression of angiogenesis in both tube formation and aortic ring assays and inhibition of matrix metalloproteinase-2 expression and activation in both HuH7 and A549 cells. Additionally, ALA dose-dependently increased the mRNA expression and protein levels of PPARγ in human THLE-2 liver cells. Conclusion ALA inhibits cancer cell motility and angiogenesis and induces PPARγ expression, which could be one of the potential mechanisms for ALA protecting against tumor progression.

Despite the consistent association between a higher intake of the provitamin A carotenoid β-cryptoxanthin (BCX) and a lower risk of lung cancer among smokers, potential mechanisms supporting BCX as a chemopreventive agent are needed. We first examined the effects of BCX on 4-[methyl nitrosamino]-1-[3-pyridyl]-1-butanone (NNK)-induced lung tumorigenesis in A/J mice. BCX supplementation was given daily to the mice starting 2 weeks prior to the injection of NNK and continued 16 weeks after NNK injection. BCX supplementation resulted in a dose-dependent increase of BCX concentration in both serum and lungs of the mice without a significant alteration of vitamin A (retinol and retinyl palmitate) concentration. BCX significantly reduced the multiplicity of the NNK-induced lung tumor by 52% to 63% compared with the NNK-treated mice without BCX supplementation. The protective effect of BCX in the lungs was associated with reductions of both mRNA and protein of the homopentameric neuronal nicotinic acetylcholine receptor α7 (α7-nAChR), which has been implicated in lung tumorigenesis. We then conducted an in vitro cell culture study and found that BCX treatment suppressed α7-nAChR expression and inhibited the migration and invasion of α7-nAChR-positive lung cancer cells but not in cells lacking α7-nAChR. The activities of BCX were significantly attenuated by activators of α7-nAChR/PI3K signaling or by overexpression of constitutively active PI3K. Collectively, the results suggest that BCX inhibits lung tumorigenesis and cancer cell motility through the downregulation of α7-nAChR/PI3K signaling, independent of its provitamin A activity. Therefore, BCX can be used as a chemopreventive agent or a chemotherapeutic compound against lung cancer. Cancer Prev Res; 9(11); 875–86. ©2016 AACR.

OBJECTIVES: Sirtuin 1 (SIRT1), a NAD(+)-dependent protein/histone deacetylase has the capability to extend life span, delay aging, and prevent aging-related diseases. There are several reports showing that there is no significant decline in SIRT1 protein with age, indicating that SIRT1 protein levels alone may not reflect its deacetylase activity. We investigated the causal effect of systemic ablation of SIRT1 deacetylase activity on aging-related pulmonary disease development in mice. METHODS: We used Sirt1(y/y) homozygous male mice carrying a point mutation (H355Y) that ablates the deacetylase activity, along with their wild type littermates (Sirt1(+/+)), and followed them for 6, 10 and 18 months of age. RESULTS: Sirt1(y/y) homozygous mice developed severe pulmonary emphysema at the ages of 6, 10 and 18 months, with the respective incidences of 33%, 100% and 100%, while the Sirt1(+/+)wild-type mice only developed emphysema (13% incidence) at 18 months of age. The development of emphysema in Sirt1(y/y) mice was accompanied with higher protein levels of matrix metalloproteinase (MMP)-2, MMP9, and tissue inhibitor of metalloproteinase-1, and ratio of cleaved/total anti-poly (ADP-ribose) polymerase. The ablation of SIRT1 activity significantly up-regulated mRNA expression of hypoxia-inducible factor-1α and retinoic acid receptor-b, while p21 protein and phosphorylated AMPK increased and phosphorylated ribosomal S6 decreased, suggesting the association of ablation of SIRT1 activity with cellular quiescence and senescence. Additionally, the lack of SIRT1 activity down-regulated the mRNA expression of circadian clock genes (BMAL1, NPAS2, CRY1, CRY2) in the lungs of Sirt1(y/y) mice, as compared with that of Sirt1(+/+) mice. There were no inflammatory responses in the lungs (e.g., inflammatory cell infiltrations, mRNA expressions of IL-6 and TNFα) in Sirt1(y/y) homozygous mice compared to Sirt1(+/+) mice. CONCLUSIONS: The lacking of SIRT1 enzymatic activity plays a major role in the susceptibility of organs to aging and pulmonary emphysema development by inducing cellular senescence and disrupting circadian clock genes. FUNDING SOURCES: USDA/ARS (58-1950-0074) and NIFA/AFRI (2017-67017-26363).

BACKGROUND β-Cryptoxanthin (BCX), a provitamin A carotenoid shown to protect against nonalcoholic fatty liver disease (NAFLD), can be cleaved by β-carotene-15,15'-oxygenase (BCO1) to generate vitamin A, and by β-carotene-9',10'-oxygenase (BCO2) to produce bioactive apo-carotenoids. BCO1/BCO2 polymorphisms have been associated with variations in plasma carotenoid amounts in both humans and animals. OBJECTIVES We investigated whether BCX feeding inhibits high refined-carbohydrate diet (HRCD)-induced NAFLD, dependent or independent of BCO1/BCO2. METHODS Six-week-old male wild-type (WT) and BCO1-/-/BCO2-/- double knockout (DKO) mice were randomly fed HRCD (66.5% of energy from carbohydrate) with or without BCX (10 mg/kg diet) for 24 wk. Pathological and biochemical variables were analyzed in the liver and mesenteric adipose tissues (MATs). Data were analyzed by 2-factor ANOVA. RESULTS Compared to their respective HRCD controls, BCX reduced hepatic steatosis severity by 33‒43% and hepatic total cholesterol by 43‒70% in both WT and DKO mice (P

Early epidemiologic studies have reported that tobacco smoking, which is causally associated with liver cancer, is an independent risk factor for non-alcoholic fatty liver diseases (NAFLD). Lycopene from tomatoes has been shown to be a potential preventive agent against NAFLD and hepatocellular carcinoma (HCC). In the present study, we investigated whether the tobacco carcinogen 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) induces lesions in both lungs and livers of ferrets with or without lycopene intervention. Male ferrets (6 groups, n = 8-10) were treated either with NNK (50 mg/kg BW, i.p., once a month for four consecutive months) or saline with or without dietary lycopene supplementation (2.2 and 6.6 mg/kg BW/day, respectively) for 26 weeks. Results demonstrate that NNK exposure results in higher incidences of lung tumors, HCC and steatohepatitis (which is characterized by severe inflammatory cell infiltration with concurrent fat accumulation in liver, hepatocellular ballooning degeneration and increased NF-κB expression), as well as elevations in bilirubin and AST levels in ferrets. Lycopene supplementation at two doses prevented NNK-induced expressions of α7 nicotinic acetylcholine receptor in the lung and NF-κB and CYP2E1 in the liver and attenuated the NNK-induced mortality and pathological lesions in both the lungs and livers of ferrets. The present study provided strong experimental evidence that the tobacco carcinogen NNK can induce both HCC and steatohepatitis in the ferrets and can be a useful model for studying tobacco carcinogen-associated NAFLD and liver cancer. Furthermore, lycopene could provide potential benefits against smoke carcinogen-induced pulmonary and hepatic injury.

OBJECTIVES: Nonalcoholic fatty liver disease (NAFLD) incidence and prevalence have been reported to be higher in men than women, however, the effects of sexual dimorphism on NAFLD risk and progression have not been adequately examined. Our lab has previously shown that a liquid high-refined carbohydrate diet (HRCD) induced more severe hepatic steatosis compared to an isocaloric high fat diet in male mice. Also, HRCD-induced reduction in sirtuin 1 (SIRT1), an NAD-dependent deacetylase protein, has previously been implicated in NAFLD pathogenesis. Therefore, we investigated whether there were sexually dimorphic responses to a liquid high-refined carbohydrate diet (HRCD) in male and female, wildtype and SIRT1-deficient mice. METHODS: Male and female 10–12-week-old wildtype (SIRT1 +/+: n = 12; M = 6, F = 6) and mice carrying a heterozygous H355Y SIRT1 point mutation (SIRT1 +/y: n = 14; M = 7, F = 7) were both fed a HRCD (Lieber-DeCarli liquid diet supplemented with maltose dextrin; 47% energy from refined carbohydrate, Dyets, #710,260) for 5 weeks and 9 weeks. Hepatic gene expression was examined using qRT-PCR. Plasma ALT (alanine transaminase) and hepatic MDA (malondialdehyde) levels were determined using colorimetric assay kits. Hepatic steatosis scoring was conducted by analyzing Hematoxylin and Eosin (H&E) stains. RESULTS: 9 weeks of HRCD induced significantly less hepatic steatosis in female mice irrespective of genotype compared to male mice as determined by grading of H&E stains (P

Scope β-Cryptoxanthin (BCX) can be cleaved by both β-carotene 15,15'-oxygenase (BCO1) and β-carotene 9',10'-oxygenase (BCO2), generating biological active vitamin A and apocarotenoids. We examined whether BCX feeding could inhibit diethylnitrosamine (DEN)-initiated, highly refined carbohydrate diet (HRCD)-promoted hepatocellular carcinoma (HCC) development, dependent or independent of BCO1/BCO2 activity. Methods and results Two-week-old male wild-type (WT) and BCO1-/- /BCO2-/- double knockout (DKO) mice are given a single intraperitoneal injection of DEN (25 mg kg-1 body weight) to initiate hepatic carcinogenesis. At 6 weeks of age, all animals are fed HRCD (66.5% of energy from carbohydrate) with or without BCX for 24 weeks. BCX feeding increases hepatic vitamin A levels in WT mice, but not in DKO mice that shows a significant accumulation of hepatic BCX. Compared to their respective HRCD littermates, both WT and DKO fed BCX have significantly lower HCC multiplicity, average tumor size, and total tumor volume, and the steatosis scores. The chemopreventive effects of BCX are associated with increased p53 protein acetylation and decreased protein levels of lactate dehydrogenase and hypoxia-inducible factor-1α in tumors. Conclusion This study suggests that BCX feeding may alleviate HRCD-promoted HCC progression by modulating the acetylation of p53, hypoxic tumor microenvironment, and glucose metabolism, independent of BCO1/BCO2.

Both incidence and death rate due to liver cancer have increased in the United States. Higher consumption of lycopene-rich tomato and tomato products is associated with a decreased risk of cancers. β-Carotene-15, 15′-oxygenase (BCO1), and β-carotene-9′, 10′-oxygenase (BCO2) cleave lycopene to produce bioactive apo-lycopenoids. Although BCO1/BCO2 polymorphisms affect human and animal lycopene levels, whether dietary tomato consumption can inhibit high-fat diet (HFD)–promoted hepatocellular carcinoma (HCC) development and affect gut microbiota in the absence of BCO1/BCO2 is unclear. BCO1/BCO2 double knockout mice were initiated with a hepatic carcinogen (diethylnitrosamine) at 2 weeks of age. At 6 weeks of age, the mice were randomly assigned to an HFD (60% of energy as fat) with or without tomato powder (TP) feeding for 24 weeks. Results showed that TP feeding significantly decreased HCC development (67%, 83%, and 95% reduction in incidence, multiplicity, and tumor volume, respectively, P < 0.05). Protective effects of TP feeding were associated with (1) decreased hepatic inflammatory foci development and mRNA expression of proinflammatory biomarkers (IL1β, IL6, IL12α, monocyte chemoattractant protein-1, and inducible NO synthase); (2) increased mRNA expression of deacetylase sirtuin 1 and nicotinamide phosphoribosyltransferase involving NAD+ production; and (3) increased hepatic circadian clock genes (circadian locomotor output cycles kaput, period 2, and cryptochrome-2, Wee1). Furthermore, TP feeding increased gut microbial richness and diversity, and significantly decreased the relative abundance of the genus Clostridium and Mucispirillum, respectively. The present study demonstrates that dietary tomato feeding independent of carotenoid cleavage enzymes prevents HFD-induced inflammation with potential modulating gut microbiota and inhibits HFD-promoted HCC development.

Sirtuin 1 (SIRT1) has been reported to protect against nonalcoholic fatty liver disease (NAFLD) development. The mechanism of how SIRT1 deacetylase activity affects NAFLD has not been well investigated. The current investigation addressed the causal effect of systemic SIRT1 activity on NAFLD development and the underlying mechanism involved in both liver and mesenteric adipose tissue (MAT). Both SIRT1 homozygous mice ablated the catalytic activity (sirt1Y/Y) and their corresponding wild type littermates (WT) were fed a high fat diet (HFD, 60% calories from fat) for 34weeks. Sirt1Y/Y mice showed significantly higher level of hepatic triglyceride which was accompanied with higher levels of SREBP-1 and SCD1and decreased phosphorylation of LKB1 and AMPK in the liver. Compared with WT mice, mRNA expression of lipogenic genes (lxrα, srebp-1c, scd1 and fas) in the MAT increased significantly in sirt1Y/Y mice. Fatty acid oxidation biomarkers (acox1, acox3, cpt, ucp1, sirt3) in both liver and MAT were comparable between groups. Interestingly, we observed that in sirt1Y/Y mice, the mRNA level of hormone sensitive lipase (hsl), adipose triglyceride lipase (atgl) and perilipin-2 (plin-2), all involved in lipolysis, significantly increased in MAT, but not in epididymal adipose tissue. These changes positively correlated with circulating free fatty acid (FFA) concentrations and higher hepatic mRNA expression of cd36 for FFA uptake. The present study has provided novel evidence to suggest that under HFD-induced metabolic surplus, the lack of SIRT1 catalytic activity promotes release of FFA from MAT and escalate NAFLD by interfering with lipid homeostasis in both liver and MAT.

Sirtuin 1 (SIRT1) has been reported to protect against nonalcoholic fatty liver disease (NAFLD) development. The mechanism of how SIRT1 deacetylase activity affects NAFLD has not been well investigated. The current investigation addressed the causal effect of systemic SIRT1 activity on NAFLD development and the underlying mechanism involved in both liver and mesenteric adipose tissue (MAT). Both SIRT1 homozygous mice ablated the catalytic activity (sirt1Y/Y) and their corresponding wild type littermates (WT) were fed a high fat diet (HFD, 60% calories from fat) for 34weeks. Sirt1Y/Y mice showed significantly higher level of hepatic triglyceride which was accompanied with higher levels of SREBP-1 and SCD1and decreased phosphorylation of LKB1 and AMPK in the liver. Compared with WT mice, mRNA expression of lipogenic genes (lxrα, srebp-1c, scd1 and fas) in the MAT increased significantly in sirt1Y/Y mice. Fatty acid oxidation biomarkers (acox1, acox3, cpt, ucp1, sirt3) in both liver and MAT were comparable between groups. Interestingly, we observed that in sirt1Y/Y mice, the mRNA level of hormone sensitive lipase (hsl), adipose triglyceride lipase (atgl) and perilipin-2 (plin-2), all involved in lipolysis, significantly increased in MAT, but not in epididymal adipose tissue. These changes positively correlated with circulating free fatty acid (FFA) concentrations and higher hepatic mRNA expression of cd36 for FFA uptake. The present study has provided novel evidence to suggest that under HFD-induced metabolic surplus, the lack of SIRT1 catalytic activity promotes release of FFA from MAT and escalate NAFLD by interfering with lipid homeostasis in both liver and MAT.

OBJECTIVES: β-Cryptoxanthin (BCX), a provitamin A carotenoid, is cleaved by carotenoid cleavage enzymes including β-carotene-15, 15′-oxygenase (BCO1) to generate vitamin A, and β-carotene-9′, 10′-oxygenase (BCO2) which yields bioactive apo-carotenoids. Dietary supplementation of BCX can prevent non-alcoholic fatty liver disease (NAFLD), which is the most common chronic liver disease worldwide. This study aimed to investigate whether BCX-mediated protection against NAFLD proceeds through the liver-mesenteric adipose tissue axis depending on the presence or absence of BCO1/BCO2. METHODS: Six-week-old male wild type (WT) mice (n = 30) and congenic BCO1(−/−)/BCO2(−/−) double KO (DKO) mice (n = 30) were randomly fed either a high-refined carbohydrate diet (HRCD, 66.5% CHO) or HRCD with BCX (10 mg/kg diet) for 24 weeks. RESULTS: Hepatic levels of BCX, but not retinol and retinyl palmitate, were significantly (P

Obesity is associated with increased risk in hepatocellular carcinoma (HCC) development and mortality. An important disease control strategy is the prevention of obesity-related hepatic inflammation and tumorigenesis by dietary means. Here, we report that apo-10′-lycopenoic acid (APO10LA), a cleavage metabolite of lycopene at its 9′,10′-double bond by carotene-9′,10′-oxygenase, functions as an effective chemopreventative agent against hepatic tumorigenesis and inflammation. APO10LA treatment on human liver THLE-2 and HuH7 cells dose dependently inhibited cell growth and upregulated sirtuin 1 (SIRT1), a NAD+-dependent protein deacetylase that may suppress hepatic carcinogenesis. This observed SIRT1 induction was associated with decreased cyclin D1 protein, increased cyclin-dependent kinase inhibitor p21 protein expression, and induced apoptosis. APO10LA supplementation (10 mg/kg diet) for 24 weeks significantly reduced diethylnitrosamine-initiated, high fat diet (HFD)–promoted hepatic tumorigenesis (50% reduction in tumor multiplicity; 65% in volume) and lung tumor incidence (85% reduction) in C57Bl/6J mice. The chemopreventative effects of APO10LA were associated with increased hepatic SIRT1 protein and deacetylation of SIRT1 targets, as well as with decreased caspase-1 activation and SIRT1 protein cleavage. APO10LA supplementation in diet improved glucose intolerance and reduced hepatic inflammation [decreased inflammatory foci, TNFα, interleukin (IL)-6, NF-κB p65 protein expression, and STAT3 activation] in HFD-fed mice. Furthermore, APO10LA suppressed Akt activation, cyclin D1 gene, and protein expression and promoted PARP protein cleavage in transformed cells within liver tumors. Taken together, these data indicate that APO10LA can effectively inhibit HFD-promoted hepatic tumorigenesis by stimulating SIRT1 signaling while reducing hepatic inflammation. Cancer Prev Res; 6(12); 1304–16. ©2013 AACR.

Objective Development of new animal lung cancer models that are relevant to human lung carcinogenesis is important for lung cancer research. Previously we have shown the induction of lung tumor in ferrets (Mustela putorius furo) exposed to both tobacco smoke and a tobacco carcinogen (4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone, NNK). In the present study, we investigated whether NNK treatment alone induces both preneoplastic and neoplastic lesions in the lungs of ferrets. Methods We exposed ferrets to NNK by i.p. injection of NNK (50 mg/kg BW) once a month for four consecutive months and then followed up for 24, 26 and 32 weeks. The incidences of pulmonary preneoplastic and neoplastic lesions were assessed by histopathological examination. The expressions of α7 nicotinic acetylcholine receptor (α7 nAChR, which has been shown to promote lung carcinogenesis) and its related molecular biomarkers in lungs were examined by immunohistochemistry and/or Western blotting analysis. Results Ferrets exposed to NNK alone developed both preneoplastic lesions (squamous metaplasia, dysplasia and atypical adenomatous hyperplasia) and tumors (squamous cell carcinoma, adenocarcinoma and adenosquamous carcinoma), which are commonly seen in humans. The incidence of tumor induced by NNK was time-dependent in the ferrets (16.7%, 40.0% and 66.7% for 24, 26 and 32 weeks, respectively). α7 nAChR is highly expressed in the ferret bronchial/bronchiolar epithelial cells, and alveolar macrophages in ferrets exposed to NNK, and in both squamous cell carcinoma and adenocarcinoma of the ferrets. In addition, we observed the tendency for an increase in phospho-ERK and cyclin D1 protein levels (p = 0.081 and 0.080, respectively) in the lungs of ferrets exposed to NNK. Conclusion The development of both preneoplastic and neoplastic lesions in ferret lungs by injecting NNK alone provides a simple and highly relevant non-rodent model for studying biomarkers/molecular targets for the prevention, detection and treatment of lung carcinogenesis in humans.

Consumption of tomatoes and tomato products which are rich in lycopene, is associated with a decreased risk of chronic disease. Lycopene can be cleaved by beta-carotene-15, 15′-oxygenase (BCO1) and...

Lycopene has been shown to be beneficial in protecting against high-fat diet-induced fatty liver. The recent demonstration that lycopene can be converted by carotene 9',10'-oxygenase into a biologically active metabolite, ALA, led us to propose that the function of lycopene can be mediated by ALA. In the present study, male ob/ob mice were fed a liquid high-fat diet (60% energy from fat) with ALA supplementation (ALA group, 240 μg · kg body weight(-1) · d(-1)) or without ALA supplementation as the control (C group) for 16 wk. Steatosis, SIRT1 expression and activity, genes involved in lipid metabolism, and ALA concentrations in the livers of mice were examined. The results showed that ALA supplementation resulted in a significant accumulation of ALA in the liver and markedly decreased the steatosis in the ALA group without altering body and liver weights compared to the C group. The mRNA and protein levels of hepatic SIRT1 were higher in the ALA group compared to the C group. SIRT1 activity also was higher in the ALA group, as indicated by the lower levels of acetylated forkhead box class O1 protein levels. In addition, the mRNA level of acetyl CoA carboxylase 1 was significantly lower in the ALA group than in the C group. Because SIRT1 plays a key role in lipid homeostasis, the present study suggests that the lycopene metabolite, ALA, protects against the development of steatosis in ob/ob mice by upregulating SIRT1 gene expression and activity.

To investigate the different effects of isocaloric high-fat diet (HFD) and high-carbohydrate diet (HCD) on hepatic steatosis and the underlying mechanisms, especially the role of microRNA-34a/silent information regulator T1 (SIRT1) axis, C57BL/6J mice (n = 12/group) were isocaloric pair-fed with Lieber-DeCarli liquid diet containing either high fat (HFLD) or high carbohydrate (HCLD) for 16 weeks. As compared to the HFLD fed mice, despite the similar final body weights, HCLD feeding: (1) induced more severe hepatic steatosis; (2) up-regulated hepatic expression of miR-34a accompanied with significant decrease of SIRT1 and nicotinamide phosphoribosyltransferase (NAMPT), SIRT1 activity and phosphorylation of AMPK; (3) up-regulated de novo lipogenesis (DNL) related proteins expression (ACC, SCD1) and down-regulated expressions of miR-122, miR-370 and miR-33; (4) decreased mRNA expressions of genes Cpt1, Pparα and Pgc1α related to fatty acid oxidation; (5) increased hepatic total cholesterol concentration and decreased expression of cholesterol metabolism related genes Abcg5, Abcg8, Abcg11, Cyp7a1 and Cyp8b1; and (6) induced higher hepatic inflammatory response accompanied with significant increased mRNA expressions of Il1β, Tnfα and Mcp1. Thus, isocaloric HCLD feeding induced greater severity in hepatic steatosis and inflammatory response than HFLD feeding, potentially through miR-34a/SIRT1 axis mediated promotion of DNL, inhibition of fatty acid oxidation and cholesterol metabolism.

Background Tumor progression locus 2 (TPL2), a serine-threonine kinase, functions as a critical regulator of inflammatory pathways and mediates oncogenic events. The potential role of Tpl2 in nonalcoholic fatty liver disease (NAFLD) associated hepatocellular carcinoma (HCC) development remains unknown. Methods Both wild-type and Tpl2 knockout male mice were initiated by a hepatic carcinogen (diethylnitrosamine, i.p. with a single dose of 25 mg.kg−1)at 2 weeks of age, and then were given the high carbohydrate diet feeding to induce hepatic steatosis, inflammation, adenoma and HCC for 24 weeks. Results Tpl2 knockout mice had significantly lower incidences of liver tumor and developed hepatocellular adenoma only, which is contrast to wild-type mice where they all developed HCC. Tpl2 knockout mice had significantly down-regulated phosphorylation of JNK and ERK, and levels of mRNA expression of pro-inflammatory cytokines (Il-1β, Il-18, Mcp-1 and Nalp3), which correlated with the reduced incidence and number of hepatic inflammatory foci. Furthermore, Tpl2 ablation resulted in decreased hepatic steatosis and expression of de novo lipogenesis related markers (ACC, SCD1, SREBP1C and AKT phosphorylation), as well as reduction of endoplasmic reticulum stress biomarkers PERK and eIF-2a. Conclusion The study revealed for the first time that Tpl2 plays a significant role in promoting HCC development by its pro-inflammatory effect, which suggested that Tpl2 could be a molecular target for HCC prevention.

SCOPE Beta-carotene-15,15'-oxygenase (BCO1) and beta-carotene-9',10'-oxygenase (BCO2) metabolize lycopene to biologically active metabolites, which can ameliorate nonalcoholic fatty liver disease (NAFLD). We investigate the effects of tomato powder (TP containing substantial lycopene (2.3 mg/g)) on NAFLD development and gut microbiome in the absence of both BCO1 and BCO2 in mice. METHOD AND RESULTS BCO1-/- /BCO2-/- double knockout mice were fed a high fat diet (HFD) alone (n = 9) or with TP feeding (n = 9) for 24 weeks. TP feeding significantly reduced pathological severity of steatosis and hepatic triglyceride levels in BCO1-/- /BCO2-/- mice (p < 0.04 vs HFD alone). This was associated with increased SIRT1 activity, nicotinamide phosphoribosyltransferase expression and AMP-activated protein kinase phosphorylation, and subsequently decreased lipogenesis, hepatic fatty acid uptake, and increasing fatty acid β-oxidation (p < 0.05). TP feeding significantly decreased mRNA expression of proinflammatory genes (tnf-α, il-1β, and il-6) in both liver and mesenteric adipose tissue, which were associated with increased plasma adiponectin and hepatic adiponectin receptor-2. Multiplexed 16S rRNA gene sequencing was performed using DNA extracted from cecum fecal samples. TP feeding increased microbial richness and decreased relative abundance of the genus Clostridium. CONCLUSION Dietary TP can inhibit NAFLD independent of carotenoid cleavage enzymes, potentially through increasing SIRT1 activity and adiponectin production and decreasing Clostridium abundance.

Tumor progression locus 2 (TPL2) is a serine-threonine kinase that functions as a critical regulator of inflammatory pathways and participates in oncogenic events. Non-alcoholic fatty liver disease...

Recent findings of an inverse association between beta-cryptoxanthin and lung cancer risk in several observational epidemiologic studies suggest that beta-cryptoxanthin could potentially act as a chemopreventive agent against lung cancer. However, the biological activity of beta-cryptoxanthin and molecular mechanism(s) by which beta-cryptoxanthin affects lung tumourigenesis have not been studied. In the present study, we found that beta-cryptoxanthin inhibited the growth of A549 cells, a non-small-cell lung cancer cell line and BEAS-2B cells, an immortalized human bronchial epithelial cell line in a dose-dependent manner. beta-Cryptoxanthin suppressed the protein levels of cyclin D1 and cyclin E, up-regulated the cell cycle inhibitor p21, increased the number of lung cancer cells in the G1/G0 phase and decreased those in the S phase of the cell cycle. Consistent with inhibition of the lung cancer cell growth, beta-cryptoxanthin induced the mRNA levels of retinoic acid receptor beta (RARbeta) in BEAS-2B cells, although this effect was less pronounced in A549 cells. Furthermore, beta-cryptoxanthin transactivated RAR-mediated transcription activity of the retinoic acid response element. These findings suggest a mechanism of anti-proliferative action of beta-cryptoxanthin and indicate that beta-cryptoxanthin may be a promising chemopreventive agent against lung cancer.

Low-dose beta-carotene (BC) supplementation, such as would be provided by daily consumption of approximately 5-9 servings of fruits and vegetables, has no apparent detrimental effects, but rather appears to have a protective effect against cigarette smoke-induced lung lesions in ferrets. In the present study, we investigated the effects of BC, beta-apo-14'-carotenoic acid (14'CA), or benzo[a]pyrene (BP; a primary lung carcinogen from cigarette smoke) treatments, either alone or in combination, on cell growth and expression of the retinoic acid receptor (RAR) of normal human bronchial epithelial (NHBE) cells. We found that both BC and 14'CA inhibited the growth of NHBE cells (P < 0.05) with or without BP. The level of RARbeta, a tumor suppressor, but not RARalpha or RARgamma, was reduced by 50% in the NHBE cells treated with BP. However, treatment with either BC or 14'CA significantly induced the expression of RARbeta in the NHBE cells, and prevented the reduction of RARbeta by BP. Furthermore, 14'CA transactivated the RARbeta promoter primarily via its conversion to retinoic acid (RA). In the presence of 3-mercaptopropionic acid, an inhibitor of fatty acid oxidation, both RA formation and transactivation activity from 14'CA were decreased. These observations indicate that the growth inhibitory effects of BC and beta-apo-carotenoic acid are through their conversion to RA and upregulation of RARbeta.

Rho GTPases regulate several aspects of tissue morphogenesis during animal development. We found that mice lacking the Rho-inhibitory protein, p190-B RhoGAP, are 30% reduced in size and exhibit developmental defects strikingly similar to those seen in mice lacking the CREB transcription factor. In p190-B RhoGAP-deficient mice, CREB phosphorylation is substantially reduced in embryonic tissues. Embryo-derived cells contain abnormally high levels of active Rho protein, are reduced in size, and exhibit defects in CREB activation upon exposure to insulin or IGF-1. The cell size defect is rescued by expression of constitutively activated CREB, and in wild-type cells, expression of activated Rho or dominant-negative CREB results in reduced cell size. Together, these results suggest that activity of the Rho GTPase modulates a signal from insulin/IGFs to CREB that determines cell size and animal size during embryogenesis.

Many cellular signaling proteins contain SH3 (Src homology 3) domains that mediate protein interactions via specific proline-containing peptides. Unlike SH2 domains, whose interactions with tyrosine-containing peptides are promoted by phosphorylation of the SH2 binding site, the regulatory mechanism for SH3 interactions is unclear. p120 RasGAP (GTPase-activating protein), which contains an SH3 domain flanked by two SH2 domains, forms an abundant SH2-mediated complex with p190 RhoGAP in cells expressing activated tyrosine kinases. We have identified two closely linked tyrosine-containing peptides in p190 that bind simultaneously to the RasGAP SH2 domains upon p190 phosphorylation. This interaction is expected to bring the two SH2 domains into close proximity. Consequently, RasGAP undergoes a conformational change that results in a 100-fold increase in the accessibility of the target binding surface of its SH3 domain. These results indicate that the tandem arrangement of SH2 and SH3 domains found in a variety of cellular signaling proteins can provide a conformational mechanism for regulating SH3-dependent interactions through tyrosine phosphorylation. In addition, it appears that the role of p190 in the RasGAP signaling complex is to promote additional protein interactions with RasGAP via its SH3 domain.

Nicotine, a large constituent of cigarette smoke, is associated with an increased risk of lung cancer, but the data supporting this relationship are inconsistent. Here, we found that nicotine treatment not only induced emphysema but also increased both lung tumor multiplicity and volume in 4-nitrosamino-1-(3-pyridyl)-1-butanone (NNK)-initiated lung cancer in A/J mice. This tumor-promoting effect of nicotine was accompanied by significant reductions in survival probability and lung Sirtuin 1 (SIRT1) expression, which has been proposed as a tumor suppressor. The decreased level of SIRT1 was associated with increased levels of AKT phosphorylation and interleukin (il)-6 mRNA but decreased tumor suppressor p53 and retinoic acid receptor (RAR)-β mRNA levels in the lungs. Using this mouse model, we then determined whether β-cryptoxanthin (BCX), a xanthophyll that is strongly associated with a reduced risk of lung cancer in several cohort studies, can inhibit nicotine-induced emphysema and lung tumorigenesis. We found that BCX supplementation at two different doses was associated with reductions of the nicotine-promoted lung tumor multiplicity and volume, as well as emphysema in mice treated with both NNK and nicotine. Moreover, BCX supplementation restored the nicotine-suppressed expression of lung SIRT1, p53, and RAR-β to that of the control group, increased survival probability, and decreased the levels of lung il-6 mRNA and phosphorylation of AKT. The present study indicates that BCX is a preventive agent against emphysema and lung cancer with SIRT1 as a potential target. In addition, our study establishes a relevant animal lung cancer model for studying tumor growth within emphysematous microenvironments. Cancer Prev Res; 6(4); 309–20. ©2012 AACR.

In mitogenically stimulated cells, a specific complex forms between the Ras GTPase-activating protein (RasGAP) and the cellular protein p190. We have previously reported that p190 contains a carboxy-terminal domain that functions as a GAP for the Rho family GTPases. Thus, the RasGAP-p190 complex may serve to couple Ras- and Rho-mediated signalling pathways. In addition to its RhoGAP domain, p190 contains an amino-terminal domain that contains sequence motifs found in all known GTPases. Here, we report that p190 binds GTP and GDP through this conserved domain and that the structural requirements for binding are similar to those seen with other GTPases. While the purified protein is unable to hydrolyze GTP, we detect an activity in cell lysates that can promote GTP hydrolysis by p190. A mutated form of p190 that fails to bind nucleotide retains its RasGAP binding and RhoGAP activities, indicating that GTP binding by p190 is not required for these functions. The sequence of p190 in the GTP-binding domain, which shares structural features with both the Ras-like small GTPases and the larger G proteins, suggests that this protein defines a novel class of guanine nucleotide-binding proteins.

Phorbol 12-myristate 13-acetate (PMA)-stimulated phosphorylation of the human insulin receptor (IR) was characterized and compared in two cell types of different lineage: normal rat kidney epithelial (NRK) cells and Chinese hamster ovary (CHO) fibroblasts. PMA stimulation increased IR beta-subunit phosphorylation to 252 +/- 43 and 25- +/- 47% (+/- S.D.) of the unstimulated control in NRK and CHO cells respectively. Tryptic phosphopeptide analysis by Tricine/SDS/PAGE revealed significant differences in the PMA-stimulated phosphorylation of the IR in these two cell types. This phosphorylation of the IR was predominantly located in two tryptic phosphopeptides, and these phosphopeptides were absent in an IR mutant truncated by 43 C-terminal amino acids. The major PMA-stimulated tryptic phosphopeptide from in vivo-labelled CHO/IR was immunoprecipitated with an antibody against residues Ser1315 to Lys1329, and this precipitation was blocked with excess unlabelled peptide containing this sequence. Radiosequencing by manual Edman degradation revealed that this tryptic phosphopeptide was phosphorylated at Ser1315. This PMA-stimulated phosphorylation did not inhibit autophosphorylation of the IR in vivo. These results demonstrate that PMA-stimulated phosphorylation of the IR can exhibit significant differences when expressed in different cell types, and that Ser1315 is a major PMA-stimulated phosphorylation site on the human IR.

Recent findings of an inverse association between beta-cryptoxanthin and lung cancer risk in several observational epidemiologic studies suggest that beta-cryptoxanthin could potentially act as a chemopreventive agent against lung cancer. However, the biological activity of beta-cryptoxanthin and molecular mechanism(s) by which beta-cryptoxanthin affects lung tumourigenesis have not been studied. In the present study, we found that beta-cryptoxanthin inhibited the growth of A549 cells, a non-small-cell lung cancer cell line and BEAS-2B cells, an immortalized human bronchial epithelial cell line in a dose-dependent manner. beta-Cryptoxanthin suppressed the protein levels of cyclin D1 and cyclin E, up-regulated the cell cycle inhibitor p21, increased the number of lung cancer cells in the G1/G0 phase and decreased those in the S phase of the cell cycle. Consistent with inhibition of the lung cancer cell growth, beta-cryptoxanthin induced the mRNA levels of retinoic acid receptor beta (RARbeta) in BEAS-2B cells, although this effect was less pronounced in A549 cells. Furthermore, beta-cryptoxanthin transactivated RAR-mediated transcription activity of the retinoic acid response element. These findings suggest a mechanism of anti-proliferative action of beta-cryptoxanthin and indicate that beta-cryptoxanthin may be a promising chemopreventive agent against lung cancer.

Previous studies have shown that beta-carotene 15,15'-monooxygenase catalyzes the cleavage of beta-carotene at the central carbon 15,15'-double bond but cleaves lycopene with much lower activity. However, expressing the mouse carotene 9',10'-monooxygenase (CMO2) in beta-carotene/lycopene-synthesizing and -accumulating Escherichia coli strains leads to both a color shift and formation of apo-10'-carotenoids, suggesting the oxidative cleavage of both carotenoids at their 9',10'-double bond. Here we provide information on the biochemical characterization of CMO2 of the ferret, a model for human carotenoid metabolism, in terms of the kinetic analysis of beta-carotene/lycopene cleavage into beta-apo-10'-carotenal/apo-10'-lycopenal in vitro and the formation of apo-10'-lycopenoids in ferrets in vivo. We demonstrate that the recombinant ferret CMO2 catalyzes the excentric cleavage of both all-trans-beta-carotene and the 5-cis- and 13-cis-isomers of lycopene at the 9',10'-double bond but not all-trans-lycopene. The cleavage activity of ferret CMO2 was higher toward lycopene cis-isomers as compared with beta-carotene as substrate. Iron was an essential co-factor for the reaction. Furthermore, all-trans-lycopene supplementation in ferrets resulted in significant accumulation of cis-isomers of lycopene and the formation of apo-10'-lycopenol, as well as up-regulation of the CMO2 expression in lung tissues. In addition, in vitro incubation of apo-10'-lycopenal with the post-nuclear fraction of hepatic homogenates of ferrets resulted in the production of both apo-10'-lycopenoic acid and apo-10'-lycopenol, respectively, depending upon the presence of NAD+ or NADH as cofactors. Our finding of bioconversion of cis-isomers of lycopene into apo-10'-lycopenoids by CMO2 is significant because cis-isomers of lycopene are a predominant form of lycopene in mammalian tissues and apo-lycopenoids may have specific biological activities related to human health.

The p190 RhoGAPs, p190A and p190B, are highly related GTPase-activating proteins for the Rho GTPases. Rho GTPases and p190A reportedly control various aspects of brain development, and we hypothesized that p190B would be likewise involved in neuronal development. We find that like p190A, p190B is prominently expressed in the developing and adult brain. Unlike p190A, p190B is not abundantly tyrosine phosphorylated. We further demonstrate, using p190B-deficient mice, that p190B is required for normal brain development. Mice lacking p190B display several major defects, including (1) deficits in the formation of major forebrain commissures, including the corpus callosum and anterior commissure, (2) dilation of the lateral ventricles, suggesting inhibition of neurogenesis and/or survival, (3) thinning of the neocortical intermediate zone, suggesting defects in neuronal differentiation and/or axonal outgrowth, and (4) impaired neuronal differentiation. These defects are similar to, but distinct from, those described in p190A-deficient mice. RNA interference-mediated knockdown of neither p190 protein results in significant inhibition of neurite outgrowth in neuroblastoma cells, despite an apparent increase in RhoA activity. We conclude that p190 RhoGAPs control pivotal aspects of neural development, including neuronal differentiation and process outgrowth, and that these effects are mediated by signaling systems that include, but are not limited to, RhoA.

beta-Catenin signaling plays an important role in the development of many organisms and has a key part in driving the malignant transformation of epithelial cells comprising a variety of cancers. beta-Catenin can activate gene expression through its association with transcription factors of the lymphoid enhancer factor 1 (LEF-1)/T-cell factor (TCF) family. We designed a screen in human cells to identify novel genes that activate a beta-catenin-LEF/TCF-responsive promoter and isolated the high-mobility group box transcription factor, UBF2. UBF1 and UBF2 are splice variants of a common precursor RNA. Although UBF1 has been shown to activate RNA polymerase I-regulated genes, the function of UBF2 has remained obscure. Here, we show for the first time that both UBF1 and UBF2 activate RNA polymerase II-regulated promoters. UBF2 associates with LEF-1, as shown by coimmunoprecipitation experiments, and potentiates transcriptional activation stimulated by LEF-1/beta-catenin from a synthetic promoter with multimerized LEF/TCF binding sites and a natural cyclin D1 promoter with consensus LEF/TCF binding sites. Downregulation of endogenous UBF expression using an RNA interference approach reduces transcriptional activation of a beta-catenin-LEF/TCF-responsive promoter by means of overexpressed beta-catenin, further implicating UBF as a transcriptional enhancer of the beta-catenin pathway.