Blood-based gene expression profile of oxidative stress and antioxidant genes for identifying surrogate markers of liver tissue injury in chronic hepatitis C patients.

Oxidative stress is the process by which reactive molecules and free radicals are formed in cells. In this study, we report the blood-based gene expression profile of oxidative stress and antioxidant genes for identifying surrogate markers of liver tissue in chronic hepatitis C (CHC) patients by using real-time PCR. A total of 144 untreated patients diagnosed with CHC having genotype 3a and 20 healthy controls were selected for the present study. Liver biopsy staging and grading of CHC patients were performed using the METAVIR score. Total RNA was extracted from liver tissue and blood samples, followed by cDNA synthesis and real-time PCR. The relative expression of genes was calculated using the ΔΔCt method. The expression profile of 84 genes associated with oxidative stress and antioxidants was determined in liver tissue and blood samples. In liver tissue, 46 differentially expressed genes (upregulated, 27; downregulated, 19) were identified in CHC patients compared to normal samples. In blood, 61 genes (upregulated, 51; downregulated; 10) were significantly expressed in CHC patients. A comparison of gene expression in liver and whole blood showed that 20 genes were expressed in a similar manner in the liver and blood. The expression levels of commonly expressed liver and blood-based genes were also correlated with clinical factors in CHC patients. A receiver operating curve (ROC) analysis of oxidative stress genes (ALB, CAT, DHCR24, GPX7, PRDX5, and MBL2) showed that infections in patients with CHC can be distinguished from healthy controls. In conclusion, blood-based gene expression can reflect the behavior of oxidative stress genes in liver tissue, and this blood-based gene expression study in CHC patients explores new blood-based non-invasive biomarkers that represent liver damage.

Reduced biliverdin reductase-A levels are associated with early alterations of insulin signaling in obesity.

Biliverdin reductase-A (BVR-A) is a serine/threonine/tyrosine kinase involved in the regulation of insulin signaling. In vitro studies have demonstrated that BVR-A is a substrate of the insulin receptor and regulates IRS1 by avoiding its aberrant activation, and in animal model of obesity the loss of hepatic BVR-A has been associated with glucose/insulin alterations and fatty liver disease. However, no studies exist in humans. Here, we evaluated BVR-A expression levels and activation in peripheral blood mononuclear cells (PBMC) from obese subjects and matched lean controls and we investigated the related molecular alterations of the insulin along with clinical correlates. We showed that BVR-A levels are significantly reduced in obese subjects and associated with a hyper-activation of the IR/IRS1/Akt/GSK-3ß/AS160/GLUT4 pathway. Low BVR-A levels also associate with the presence of obesity, metabolic syndrome, NASH and visceral adipose tissue inflammation. These data suggest that the reduction of BVR-A may be responsible for early alterations of the insulin signaling pathway in obesity and in this context may represent a novel molecular target to be investigated for the comprehension of the process of insulin resistance development in obesity.

Age-related changes of cholestanol and lathosterol plasma concentrations: an explorative study.

BACKGROUND: Cerebrotendinous xanthomatosis (CTX) and Lathosterolosis represent two treatable inherited disorders of cholesterol metabolism that are characterized by the accumulation of cholestanol and lathosterol, respectively. The age of the patients suspected of having these disorders is highly variable due to the very different phenotypes. The early diagnosis of these disorders is important because specific therapeutic treatment could prevent the disease progression. The biochemical diagnosis of these defects is generally performed analyzing the sterol profile. Since age-related levels of these sterols are lacking, this study aims to determine a preliminary comparison of plasma levels of cholestanol and lathosterol among Italian unaffected newborns, children and healthy adults. METHODS: The sterols were extracted from 130 plasma samples (24 newborns, 33 children and 73 adults) by a liquid-liquid separation method and quantified by gas chromatography coupled with a flame ionization detector. RESULTS: Cholesterol, cholestanol and lathosterol levels together with the cholestanol/cholesterol and lathosterol/cholesterol ratios are statistically different among the three groups. Cholesterol levels progressively increased from newborns to children and to adults, whereas cholestanol/cholesterol and cholestanol/lathosterol ratios progressively decreased from newborns to children and to adults. Lathosterol levels were higher in adults than in both newborns and children. In the total population a positive correlation was observed between cholesterol levels and both cholestanol (correlation coefficient = 0.290, p = 0.001) and lathosterol levels (correlation coefficient = 0.353, p <  0.0001). CONCLUSIONS: Although this study can only be considered an explorative experience due to the low number of analyzed samples, we revealed several differences of plasma cholestanol and lathosterol levels and their ratios to cholesterol levels among newborns, children and adults. These evidences indicate the need of age-related reference values of cholestanol and lathosterol concentrations, including also newborns and children.

Targeting of Hematologic Malignancies with PTC299, A Novel Potent Inhibitor of Dihydroorotate Dehydrogenase with Favorable Pharmaceutical Properties.

PTC299 was identified as an inhibitor of VEGFA mRNA translation in a phenotypic screen and evaluated in the clinic for treatment of solid tumors. To guide precision cancer treatment, we performed extensive biological characterization of the activity of PTC299 and demonstrated that inhibition of VEGF production and cell proliferation by PTC299 is linked to a decrease in uridine nucleotides by targeting dihydroorotate dehydrogenase (DHODH), a rate-limiting enzyme for de novo pyrimidine nucleotide synthesis. Unlike previously reported DHODH inhibitors that were identified using in vitro enzyme assays, PTC299 is a more potent inhibitor of DHODH in isolated mitochondria suggesting that mitochondrial membrane lipid engagement in the DHODH conformation in situ is required for its optimal activity. PTC299 has broad and potent activity against hematologic cancer cells in preclinical models, reflecting a reduced pyrimidine nucleotide salvage pathway in leukemia cells. Archived serum samples from patients treated with PTC299 demonstrated increased levels of dihydroorotate, the substrate of DHODH, indicating target engagement in patients. PTC299 has advantages over previously reported DHODH inhibitors, including greater potency, good oral bioavailability, and lack of off-target kinase inhibition and myelosuppression, and thus may be useful for the targeted treatment of hematologic malignancies.

Re-evaluation of Brequinar sodium, a dihydroorotate dehydrogenase inhibitor.

DUP-785 (Brequinar sodium) is a potent inhibitor of the mitochondrial dihydroorotate dehydrogenase (DHO-DH), a rate-limiting enzyme in the pyrimidine de novo nucleotide synthesis. In phase I clinical studies at the maximum tolerated dose (MTD) Brequinar induced a long-term inhibition of DHO-DH in white blood cells (WBC) and a long-term depletion of plasma uridine. These two parameters were related to severe myelosuppression, so that in Phase II studies the dose of Brequinar was decreased considerably. We further characterized the mechanism of DHO-DH enzyme inhibition while in blood samples of patients entered into Phase II studies we evaluated DHO-DH inhibition in WBC and plasma uridine depletion. With Electron Spin Resonance it was demonstrated that DHO-DH produced oxygen radical formation, which was inhibited by Brequinar. In the Phase II study depending on the dose (600 to 2000 mg/m2), uridine decreased to 20% (at the highest dose) or to 80-85% (at the middle dose) or did not change, which was associated with inhibition of DHO-DH (1% activity left vs 11 and 24% left). Inhibition of DHO-DH in the tumor of the latter patient was moderate as well (12% activity left). Brequinar was inactive in all tumor types evaluated possibly because of high uridine levels in the tumor. In conclusion, Brequinar was inactive against solid tumors, but DHO-DH inhibition was associated with myeloid toxicity, which may explain its potential for treatment of leukemia or inflammatory diseases.

Predictive role BLVRA mRNA expression in hepatocellular cancer.

 Introduction and aim. Hepatocellular carcinoma (HCC) is the most common primary malignant liver tumor. It is primarily caused by hepatic cirrhosis or chronic viral hepatitis. Hepatic carcinogenesis is associated with increased oxidative stress. Thus, the aim of our study was to assess expression of the genes involved in the homeostasis of oxidative stress in patients with HCC. MATERIAL AND METHODS: The study was performed on 32 patients with primary HCC (verified by liver histology in 29 patients) and 27 control subjects (in 11 subjects, liver histology was available either with no or minimal changes in the liver tissue). Gene expressions of heme oxygenase 1 (HMOX1), biliverdin reductase A/B (BLVRA/B), NADPH oxidase 2 (NOX2) and p22phox were analyzed in the liver and peripheral blood leukocytes (PBL) in the subjects. RESULTS: Compared to controls, almost a 3 times higher mRNA level of BLVRA was detected in livers of HCC patients (p = 0.002); while those of BLVRB as well as HMOX1 were unchanged (p > 0.05). In accord with these results in the liver tissue, BLVRA mRNA levels in PBL were also significantly increased in HCC patients (p = 0.012). mRNA levels of NOX2 and p22phox in the liver tissue, although higher in HCC patients, did not differ significantly compared to control subjects (p > 0.05). Nevertheless, NOX2 mRNA level in PBL was significantly higher in HCC patients (p = 0.003). CONCLUSIONS: BLVRA mRNA levels in the liver as well as in PBL are significantly higher in HCC patients most likely as a feedback mechanism to control increased oxidative stress associated with HCC progression.

Tm7sf2 may participate in the healing of burn wounds.

The transmembrane 7 superfamily member 2 (Tm7sf2) gene been reported to be involved in the reduced cholesterol levels of patients with large burn areas. To investigate the importance of Tm7sf2 in the burn wound healing process, a total of 10 Sprague­Dawley rats underwent electrical burns. Blood serum was collected for the culture of HaCaT human keratinocyte cells. Tm7sf2 small interfering RNAs (siRNAs) were prepared and transfected into the normal­ and burn serum­cultured HaCaT cells. Monocyte­endothelial cellular adhesion ability and cell proliferation, as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the levels of autophagy proteins Beclin1 and LC3­II, which were detected by western blot assay and real time­quantitative polymerase chain reaction, and it was identified that Tm7sf2 siRNAs were successfully transfected. Cell proliferation was reduced and monocyte-endothelial cell adhesion increased in the burn serum group compared with the normal serum group (P<0.05). Additionally, the expression levels of Beclin1 and LC3­II were increased, and the addition of siTm7sf2 had a similar effect as the burn serum. Thus, Tm7sf2 may take part in the burn wound healing process by interacting with LC3­II and Beclin1, and targeting Tm7sf2 may have therapeutic benefits.

Genetic variation in the vitamin d pathway in relation to risk of prostate cancer--results from the breast and prostate cancer cohort consortium.

BACKGROUND: Studies suggest that vitamin D status may be associated with prostate cancer risk although the direction and strength of this association differs between experimental and observational studies. Genome-wide association studies have identified genetic variants associated with 25-hydroxyvitamin D [25(OH)D] status. We examined prostate cancer risk in relation to single-nucleotide polymorphisms (SNP) in four genes shown to predict circulating levels of 25(OH)D. METHODS: SNP markers localized to each of four genes (GC, CYP24A1, CYP2R1, and DHCR7) previously associated with 25(OH)D were genotyped in 10,018 cases and 11,052 controls from the National Cancer Institute (NCI) Breast and Prostate Cancer Cohort Consortium. Logistic regression was used to estimate the individual and cumulative association between genetic variants and risk of overall and aggressive prostate cancer. RESULTS: We observed a decreased risk of aggressive prostate cancer among men with the allele in rs6013897 near CYP24A1 associated with lower serum 25(OH)D [per A allele, OR, 0.86; 95% confidence interval (CI), 0.80-0.93; Ptrend = 0.0002) but an increased risk for nonaggressive disease (per A allele: OR, 1.10; 95% CI, 1.04-1.17; Ptrend = 0.002). Examination of a polygenic score of the four SNPs revealed statistically significantly lower risk of aggressive prostate cancer among men with a greater number of low vitamin D alleles (OR for 6-8 vs. 0-1 alleles, 0.66; 95% CI, 0.44-0.98; Ptrend = 0.003). CONCLUSIONS: In this large, pooled analysis, genetic variants related to lower 25(OH)D levels were associated with a decreased risk of aggressive prostate cancer. IMPACT: Our genetic findings do not support a protective association between loci known to influence vitamin D levels and prostate cancer risk.

Common variants of four bilirubin metabolism genes and their association with serum bilirubin and coronary artery disease in Chinese Han population.

OBJECTIVES: Studies have revealed an inverse relationship between serum total bilirubin (TBIL) levels and coronary artery disease (CAD). This study investigated the genetic variants of four bilirubin metabolism genes--heme oxygenase-1 (HMOX1), biliverdin reductase A (BLVRA), solute carrier organic anion transporter family member 1B1 (SLCO1B1), and uridine diphosphate glycosyltransferase 1A1 (UGT1A1)--in relation to TBIL levels and CAD. METHODS AND RESULTS: Thirty-five common single nucleotide polymorphisms (SNPs) were genotyped in 2380 unrelated Han participants who underwent angiocardiography at hospitals in Shanghai, China. Only three genetic variants--rs4399719 (UGT1A1 T-2473G), rs887829 (UGT1A1 G-364A), and rs4148323 (UGT1A1 G211A)--were associated with TBIL levels (each P<0.001). Four significant associations with CAD were detected after controlling age and the false discovery rate at 15%: the recessive effect of SNP rs887829 (UGT1A1 G-364A) [age-adjusted odds ratio (OR): 0.24; 95% confidence interval (CI): 0.10-0.60; P=0.0014] and dominant effect of rs4149013 (SLCO1B1 A-12099G) (age-adjusted OR: 0.70; 95% CI: 0.55-0.91; P=0.0069) on male CAD, and the additive effects of rs2877262 (BLVRA G+1238/in6C) (age-adjusted OR: 0.73; 95% CI: 0.59-0.89; P=0.0021) and rs2690381 (BLVRA G+2613/in6A) (age-adjusted OR: 0.70; 95% CI: 0.56-0.86; P=0.0008) on female CAD. SNPs rs2877262 and rs2690381 were both in a linkage disequilibrium block within BLVRA with r greater than 0.750. Correspondingly, this block was identified to be associated with female CAD. CONCLUSION: Our study provides genetic evidences for the difference in the impact of these four bilirubin metabolism genes on TBIL levels and CAD.