Dihydroorotate dehydrogenase (DHODH) is an enzyme of the de novo pyrimidine synthesis pathway that provides nucleotides for RNA/DNA synthesis essential for proliferation. In mammalian cells, DHODH is localized in mitochondria, linked to the respiratory chain via the coenzyme Q pool. Here we discuss the role of DHODH in the oxidative phosphorylation system and in the initiation and progression of cancer. We summarize recent findings on DHODH biology, the progress made in the development of new, specific inhibitors of DHODH intended for cancer therapy, and the mechanistic insights into the consequences of DHODH inhibition.

• MeSH
• inhibitory enzymů terapeutické užití   MeSH
• lidé MeSH
• mitochondrie genetika   metabolismus   MeSH
• nádory genetika   patologie   MeSH
• oxidativní fosforylace * MeSH
• oxidoreduktasy působící na CH-CH vazby antagonisté a inhibitory   genetika   MeSH
• proliferace buněk účinky léků   MeSH
• transport elektronů genetika   MeSH
• ubichinon analogy a deriváty   genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

p53-mutated tumors often exhibit increased resistance to standard chemotherapy and enhanced metastatic potential. Here we demonstrate that inhibition of dihydroorotate dehydrogenase (DHODH), a key enzyme of the de novo pyrimidine synthesis pathway, effectively decreases proliferation of cancer cells via induction of replication and ribosomal stress in a p53- and checkpoint kinase 1 (Chk1)-dependent manner. Mechanistically, a block in replication and ribosomal biogenesis result in p53 activation paralleled by accumulation of replication forks that activate the ataxia telangiectasia and Rad3-related kinase/Chk1 pathway, both of which lead to cell cycle arrest. Since in the absence of functional p53 the cell cycle arrest fully depends on Chk1, combined DHODH/Chk1 inhibition in p53-dysfunctional cancer cells induces aberrant cell cycle re-entry and erroneous mitosis, resulting in massive cell death. Combined DHODH/Chk1 inhibition effectively suppresses p53-mutated tumors and their metastasis, and therefore presents a promising therapeutic strategy for p53-mutated cancers.

• MeSH
• checkpoint kinasa 1 antagonisté a inhibitory   genetika   metabolismus   MeSH
• fenylmočovinové sloučeniny farmakologie   MeSH
• geny erbB-2 MeSH
• HCT116 buňky MeSH
• inhibitory proteinkinas farmakologie   MeSH
• kontrolní body buněčného cyklu * účinky léků   MeSH
• leflunomid farmakologie   MeSH
• lidé MeSH
• MFC-7 buňky MeSH
• myši inbrední BALB C MeSH
• myši inbrední NOD MeSH
• myši SCID MeSH
• myši transgenní MeSH
• nádorový supresorový protein p53 nedostatek   genetika   MeSH
• nádory prsu farmakoterapie   genetika   metabolismus   patologie   MeSH
• oxidoreduktasy působící na CH-CH vazby antagonisté a inhibitory   genetika   metabolismus   MeSH
• proliferace buněk * účinky léků   MeSH
• protokoly antitumorózní kombinované chemoterapie farmakologie   MeSH
• pyraziny farmakologie   MeSH
• pyrimidiny biosyntéza   MeSH
• regulace genové exprese u nádorů MeSH
• ribozomy genetika   metabolismus   MeSH
• signální transdukce MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The development of non-genotoxic therapies that activate wild-type p53 in tumors is of great interest since the discovery of p53 as a tumor suppressor. Here we report the identification of over 100 small-molecules activating p53 in cells. We elucidate the mechanism of action of a chiral tetrahydroindazole (HZ00), and through target deconvolution, we deduce that its active enantiomer (R)-HZ00, inhibits dihydroorotate dehydrogenase (DHODH). The chiral specificity of HZ05, a more potent analog, is revealed by the crystal structure of the (R)-HZ05/DHODH complex. Twelve other DHODH inhibitor chemotypes are detailed among the p53 activators, which identifies DHODH as a frequent target for structurally diverse compounds. We observe that HZ compounds accumulate cancer cells in S-phase, increase p53 synthesis, and synergize with an inhibitor of p53 degradation to reduce tumor growth in vivo. We, therefore, propose a strategy to promote cancer cell killing by p53 instead of its reversible cell cycle arresting effect.

• MeSH
• antitumorózní látky farmakologie   MeSH
• buněčný cyklus účinky léků   MeSH
• indazoly farmakologie   MeSH
• inhibitory enzymů farmakologie   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 genetika   metabolismus   MeSH
• nádory farmakoterapie   enzymologie   genetika   metabolismus   MeSH
• oxidoreduktasy působící na CH-CH vazby antagonisté a inhibitory   chemie   genetika   metabolismus   MeSH
• proliferace buněk účinky léků   MeSH
• proteolýza účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

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.

• MeSH
• hemoxygenasa-1 genetika   MeSH
• hepatocelulární karcinom krev   enzymologie   genetika   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• membránové glykoproteiny genetika   MeSH
• messenger RNA genetika   MeSH
• nádorové biomarkery krev   genetika   MeSH
• nádory jater krev   enzymologie   genetika   patologie   MeSH
• NADPH-oxidasy genetika   MeSH
• oxidační stres genetika   MeSH
• oxidoreduktasy působící na CH-CH vazby krev   genetika   MeSH
• progrese nemoci MeSH
• regulace genové exprese enzymů MeSH
• regulace genové exprese u nádorů MeSH
• senioři MeSH
• signální transdukce MeSH
• studie případů a kontrol MeSH
• upregulace MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Leflunomide (LEF) is a disease-modifying anti-rheumatic drug used for treating rheumatoid arthritis (RA). More than 50% of patients are withdrawn from LEF treatment within one year, mainly due to AEs. Importantly, it is not possible to predict which patients will respond to LEF therapy nor if adverse outcome occurs. Pharmacogenetic studies indicate an impact of single nucleotid polymorphisms (SNPs) on the variability in LEF serum levels with potential relevance to effectiveness and tolerability in individual RA patients. In vitro studies have demonstrated that cytochromes P450 (CYPs), mainly CYP1A2, CYP2C19, and CYP3A4, are involved in LEF metabolite activation. It was shown that CYP1A2*1F allele may be associated with LEF toxicity in patients with RA. In case of dihydroorotate dehydrogenase (DHODH) gene SNP (rs3213422, 19C>A), it was shown that C allele may be associated with LEF toxicity and therapeutic effect. Finally, oestrogen receptor genes SNPs in females may be associated with LEF therapy efficacy. In summary, the results of the current studies suggest a possible diagnostic value of genotyping for patients with RA as biomarkers of LEF therapy efficacy or conversely as indicators of serious side effects. In the future, it will be necessary to corroborate these results in studies with larger numbers of patients and longer follow-up. Moreover, it would be appropriate to focus on CYP2C19, ATP5A1 and PKD1L3 genes.

• MeSH
• ABC transportéry genetika   metabolismus   MeSH
• antirevmatika škodlivé účinky   farmakokinetika   MeSH
• biotransformace genetika   MeSH
• farmakogenetika MeSH
• fenotyp MeSH
• genotyp MeSH
• isoxazoly škodlivé účinky   farmakokinetika   MeSH
• izoenzymy MeSH
• jednonukleotidový polymorfismus * MeSH
• lidé MeSH
• nádorové proteiny genetika   metabolismus   MeSH
• oxidoreduktasy působící na CH-CH vazby genetika   metabolismus   MeSH
• receptory pro estrogeny genetika   metabolismus   MeSH
• revmatoidní artritida diagnóza   farmakoterapie   MeSH
• rizikové faktory MeSH
• systém (enzymů) cytochromů P-450 genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

In most oxygenic phototrophs, including cyanobacteria, two independent enzymes catalyze the reduction of protochlorophyllide to chlorophyllide, which is the penultimate step in chlorophyll (Chl) biosynthesis. One is light-dependent NADPH:protochlorophyllide oxidoreductase (LPOR) and the second type is dark-operative protochlorophyllide oxidoreductase (DPOR). To clarify the roles of both enzymes, we assessed synthesis and accumulation of Chl-binding proteins in mutants of cyanobacterium Synechocystis PCC 6803 that either completely lack LPOR or possess low levels of the active enzyme due to its ectopic regulatable expression. The LPOR-less mutant grew photoautotrophically in moderate light and contained a maximum of 20 % of the wild-type (WT) Chl level. Both Photosystem II (PSII) and Photosystem I (PSI) were reduced to the same degree. Accumulation of PSII was mostly limited by the synthesis of antennae CP43 and especially CP47 as indicated by the accumulation of reaction center assembly complexes. The phenotype of the LPOR-less mutant was comparable to the strain lacking DPOR that also contained <25 % of the wild-type level of PSII and PSI when cultivated under light-activated heterotrophic growth conditions. However, in the latter case, we detected no reaction center assembly complexes, indicating that synthesis was almost completely inhibited for all Chl-proteins, including the D1 and D2 proteins.

• MeSH
• 2D gelová elektroforéza MeSH
• aktivace enzymů MeSH
• bakteriální proteiny genetika   metabolismus   MeSH
• buněčná membrána enzymologie   metabolismus   MeSH
• chlorofyl biosyntéza   genetika   MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• fenotyp MeSH
• fotosystém I - proteinový komplex genetika   metabolismus   MeSH
• fotosystém II - proteinový komplex genetika   metabolismus   MeSH
• fototrofní procesy MeSH
• oxidoreduktasy působící na CH-CH vazby genetika   metabolismus   MeSH
• protochlorofylid metabolismus   MeSH
• regulace genové exprese enzymů * MeSH
• regulace genové exprese u rostlin MeSH
• světlo MeSH
• Synechocystis enzymologie   genetika   metabolismus   účinky záření   MeSH
• transformace genetická MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND AND AIMS: Hepatitis C virus (HCV) infection is associated with systemic oxidative stress. Since the heme catabolic pathway plays an important role in antioxidant protection, we attempted to assess the gene expression of key enzymes of heme catabolism, heme oxygenase 1 (HMOX1), heme oxygenase 2 (HMOX2), and biliverdin reductase A (BLVRA) in the liver and peripheral blood leukocytes (PBL) of patients chronically infected with HCV. METHODS: Gene expressions (HMOX1, HMOX2, BLVRA) and HCV RNA were analyzed in PBL of HCV treatment naïve patients (n = 58) and controls (n = 55), with a subset of HCV patients having data on hepatic gene expression (n = 35). Based upon the therapeutic outcome, HCV patients were classified as either responders (n = 38) or treatment-failure patients (n = 20). Blood samples in HCV patients were collected at day 0, and week 12, 24, 36, and 48 after the initiation of standard antiviral therapy. RESULTS: Compared to the controls, substantially increased BLVRA expression was detected in PBL (p<0.001) of therapeutically naïve HCV patients. mRNA levels of BLVRA in PBL closely correlated with those in liver tissue (r2 = 0.347,p = 0.03). A marked difference in BLVRA expression in PBL between the sustained responders and patients with treatment failure was detected at week 0 and during the follow-up (p<0.001). Multivariate analysis revealed that BLVRA basal expression in PBL was an independent predictor for sustained virological response (OR 15; 95% CI 1.05-214.2; P = 0.046). HMOX1/2 expression did not have any effect on the treatment outcome. CONCLUSION: Our results suggest that patients with chronic HCV infection significantly upregulate BLVRA expression in PBL. The lack of BLVRA overexpression is associated with non-responsiveness to standard antiviral therapy; whereas, HMOX1/2 does not seem to have any predictive potential.

• MeSH
• antivirové látky terapeutické užití   MeSH
• dospělí MeSH
• exprese genu * MeSH
• hem metabolismus   MeSH
• hemová oxygenasa (decyklizující) genetika   metabolismus   MeSH
• hemoxygenasa-1 genetika   metabolismus   MeSH
• Hepacivirus * MeSH
• hepatitida C farmakoterapie   genetika   virologie   MeSH
• játra metabolismus   virologie   MeSH
• leukocyty metabolismus   virologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• metabolické sítě a dráhy genetika   MeSH
• oxidoreduktasy působící na CH-CH vazby genetika   MeSH
• ROC křivka MeSH
• výsledek terapie MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• Klíčová slova
• shh, 7-dehydrocholesterol reduktáza, 7-dehydrocholesterol,
• MeSH
• cholesterol biosyntéza   metabolismus   nedostatek   MeSH
• dehydrocholesteroly MeSH
• embryonální struktury abnormality   embryologie   MeSH
• embryonální vývoj MeSH
• krysa rodu rattus MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• myši MeSH
• oxidoreduktasy působící na CH-CH vazby genetika   nedostatek   MeSH
• proteiny hedgehog fyziologie   MeSH
• signální transdukce MeSH
• Smithův-Lemliho-Opitzův syndrom embryologie   genetika   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• přehledy MeSH

Smith-Lemli-Opitz syndrome is a rare hereditary autosomal recessive disease characterized by deficiency of 7-dehydrocholesterol reductase. Clinical picture encompasses prenatal and postnatal growth abnormalities and multisystemic structural malformations. To date, predisposition for tumor development is not considered a feature associated with this syndrome. Here, we describe a 16-year-old boy with Smith-Lemli-Opitz syndrome who developed cerebral germinoma. To our knowledge, this is the first report of association of this syndrome with malignant intracranial germ-cell tumor.

• MeSH
• cholesterol metabolismus   MeSH
• dehydrocholesteroly metabolismus   MeSH
• fatální výsledek MeSH
• germinom etiologie   MeSH
• homeostáza MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• mladiství MeSH
• morfogeneze genetika   MeSH
• nádory mozku etiologie   genetika   patologie   MeSH
• oxidoreduktasy působící na CH-CH vazby genetika   MeSH
• progrese nemoci MeSH
• proteiny hedgehog metabolismus   MeSH
• Smithův-Lemliho-Opitzův syndrom genetika   patologie   MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• Publikační typ
• kazuistiky MeSH

• MeSH
• aminokyseliny sírové genetika   MeSH
• arteriální okluzní nemoci * genetika   MeSH
• dospělí MeSH
• genetická predispozice k nemoci * genetika   MeSH
• genotyp MeSH
• hodnocení rizik MeSH
• lidé středního věku MeSH
• lidé MeSH
• matematické výpočty počítačové MeSH
• methylentetrahydrofolátreduktasa (NADPH2) MeSH
• modely genetické MeSH
• oxidoreduktasy působící na CH-CH vazby genetika   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• práce podpořená grantem MeSH