BACKGROUND: Renal cell carcinoma (RCC) is a disease typified by anomalies in cell metabolism. The function of mitochondria, including subunits of mitochondrial respiratory complex II (CII), in particular SDHB, are often affected. Here we investigated the state and function of CII in RCC patients. METHODS: We evaluated tumour tissue as well as the adjacent healthy kidney tissue of 78 patients with RCC of different histotypes, focusing on their mitochondrial function. As clear cell RCC (ccRCC) is by far the most frequent histotype of RCC, we focused on these patients, which were grouped based on the pathological WHO/ISUP grading system to low- and high-grade patients, indicative of prognosis. We also evaluated mitochondrial function in organoids derived from tumour tissue of 7 patients. RESULTS: ccRCC tumours were characterized by mutated von Hippel-Lindau gene and high expression of carbonic anhydrase IX. We found low levels of mitochondrial DNA, protein and function, together with CII function in ccRCC tumour tissue, but not in other RCC types and non-tumour tissues. Mitochondrial content increased in high-grade tumours, while the function of CII remained low. Tumour organoids from ccRCC patients recapitulated molecular characteristics of RCC tissue. CONCLUSIONS: Our findings suggest that the state of CII, epitomized by its assembly and SDHB levels, deteriorates with the progressive severity of ccRCC. These observations hold the potential for stratification of patients with worse prognosis and may guide the exploration of targeted therapeutic interventions.

• MeSH
• antigeny nádorové MeSH
• dospělí MeSH
• karboanhydrasa IX metabolismus   genetika   MeSH
• karcinom z renálních buněk * patologie   metabolismus   genetika   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mitochondriální DNA genetika   metabolismus   MeSH
• mitochondrie * metabolismus   patologie   genetika   MeSH
• mutace MeSH
• nádorový supresorový protein VHL genetika   metabolismus   MeSH
• nádory ledvin * patologie   metabolismus   genetika   MeSH
• respirační komplex II * metabolismus   genetika   MeSH
• senioři MeSH
• sukcinátdehydrogenasa genetika   metabolismus   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Tissue differentiation and proliferation throughout fetal development interconnect with changes in the oxidative phosphorylation system (OXPHOS) on the cellular level. Reevaluation of the expression data revealed a significant increase in COX4 and MTATP6 liver transcription levels after the 22(nd) gestational week (GW) which inspired us to characterize its functional impact. Specific activities of cytochrome c oxidase (COX), citrate synthase (CS), succinate-coenzyme Q reductase (SQR) and mtDNA determined by spectrophotometry and RT-PCR were studied in a set of 25 liver and 18 skeletal muscle samples at 13(th) to 29(th) GW. Additionally, liver hematopoiesis (LH) was surveyed by light microscopy. The mtDNA content positively correlated with the gestational age only in the liver. The activities of COX, CS and SQR in both liver and muscle isolated mitochondria significantly decreased after the 22(nd) GW in comparison with earlier GW. A continuous decline of LH, not correlating with the documented OXPHOS-specific activities, was observed from the 14(th) to the 24(th) GW indicating their exclusive reflection of liver tissue processes. Two apparently contradictory processes of increasing mtDNA transcription and decreasing OXPHOS-specific activities seem to be indispensable for rapid postnatal adaptation to high energy demands. The inadequate capacity of mitochondrial energy production may be an important factor in the mortality of children born before the critical developmental point of the 22(nd) GW.

• MeSH
• citrátsynthasa biosyntéza   genetika   MeSH
• genetická transkripce fyziologie   MeSH
• játra embryologie   metabolismus   MeSH
• kosterní svaly embryologie   metabolismus   MeSH
• lidé MeSH
• respirační komplex II biosyntéza   genetika   MeSH
• respirační komplex IV biosyntéza   genetika   MeSH
• těhotenství MeSH
• vývoj plodu fyziologie   MeSH
• Check Tag
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Cell growth and survival depend on a delicate balance between energy production and synthesis of metabolites. Here, we provide evidence that an alternative mitochondrial complex II (CII) assembly, designated as CIIlow, serves as a checkpoint for metabolite biosynthesis under bioenergetic stress, with cells suppressing their energy utilization by modulating DNA synthesis and cell cycle progression. Depletion of CIIlow leads to an imbalance in energy utilization and metabolite synthesis, as evidenced by recovery of the de novo pyrimidine pathway and unlocking cell cycle arrest from the S-phase. In vitro experiments are further corroborated by analysis of paraganglioma tissues from patients with sporadic, SDHA and SDHB mutations. These findings suggest that CIIlow is a core complex inside mitochondria that provides homeostatic control of cellular metabolism depending on the availability of energy.

• MeSH
• biosyntetické dráhy fyziologie   MeSH
• energetický metabolismus fyziologie   MeSH
• fyziologický stres * MeSH
• genový knockout MeSH
• HEK293 buňky MeSH
• kontrolní body fáze S buněčného cyklu fyziologie   MeSH
• lidé MeSH
• malá interferující RNA metabolismus   MeSH
• mitochondrie metabolismus   MeSH
• mutace MeSH
• myši inbrední BALB C MeSH
• myši nahé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• paragangliom genetika   patologie   MeSH
• respirační komplex II genetika   metabolismus   MeSH
• sukcinátdehydrogenasa genetika   metabolismus   MeSH
• xenogenní modely - testy antitumorózní aktivity MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Mitochondrial complex II or succinate dehydrogenase (SDH) is at the crossroads of oxidative phosphorylation and the tricarboxylic acid cycle. It has been shown that Sdh5 (SDHAF2/SDH5 in mammals) is required for flavination of the subunit Sdh1 (SDHA in human cells) in yeast. Here we demonstrate that in human breast cancer cells, SDHAF2/SDH5 is dispensable for SDHA flavination. In contrast to yeast, CRISPR-Cas9 nickase-mediated SDHAF2 KO breast cancer cells feature flavinated SDHA and retain fully assembled and functional complex II, as well as normal mitochondrial respiration. Our data show that SDHA flavination is independent of SDHAF2 in breast cancer cells, employing an alternative mechanism.

• MeSH
• flaviny MeSH
• genový knockdown MeSH
• lidé MeSH
• mitochondriální proteiny genetika   metabolismus   MeSH
• mitochondrie genetika   metabolismus   MeSH
• nádorové buněčné linie MeSH
• nádorové proteiny genetika   metabolismus   MeSH
• nádory prsu genetika   metabolismus   MeSH
• posttranslační úpravy proteinů * MeSH
• respirační komplex II genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Respiratory complex II (CII, succinate dehydrogenase, SDH) inhibition can induce cell death, but the mechanistic details need clarification. To elucidate the role of reactive oxygen species (ROS) formation upon the ubiquinone-binding (Qp) site blockade, we substituted CII subunit C (SDHC) residues lining the Qp site by site-directed mutagenesis. Cell lines carrying these mutations were characterized on the bases of CII activity and exposed to Qp site inhibitors MitoVES, thenoyltrifluoroacetone (TTFA) and Atpenin A5. We found that I56F and S68A SDHC variants, which support succinate-mediated respiration and maintain low intracellular succinate, were less efficiently inhibited by MitoVES than the wild-type (WT) variant. Importantly, associated ROS generation and cell death induction was also impaired, and cell death in the WT cells was malonate and catalase sensitive. In contrast, the S68A variant was much more susceptible to TTFA inhibition than the I56F variant or the WT CII, which was again reflected by enhanced ROS formation and increased malonate- and catalase-sensitive cell death induction. The R72C variant that accumulates intracellular succinate due to compromised CII activity was resistant to MitoVES and TTFA treatment and did not increase ROS, even though TTFA efficiently generated ROS at low succinate in mitochondria isolated from R72C cells. Similarly, the high-affinity Qp site inhibitor Atpenin A5 rapidly increased intracellular succinate in WT cells but did not induce ROS or cell death, unlike MitoVES and TTFA that upregulated succinate only moderately. These results demonstrate that cell death initiation upon CII inhibition depends on ROS and that the extent of cell death correlates with the potency of inhibition at the Qp site unless intracellular succinate is high. In addition, this validates the Qp site of CII as a target for cell death induction with relevance to cancer therapy.

• MeSH
• buněčná smrt fyziologie   MeSH
• konformace proteinů MeSH
• lidé MeSH
• mitochondrie metabolismus   fyziologie   MeSH
• molekulární sekvence - údaje MeSH
• mutageneze cílená MeSH
• respirační komplex II chemie   genetika   metabolismus   fyziologie   MeSH
• sekvence aminokyselin MeSH
• ubichinon chemie   genetika   metabolismus   MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Tumor-initiating cells (TICs) often survive therapy and give rise to second-line tumors. We tested the plausibility of sphere cultures as models of TICs. Microarray data and microRNA data analysis confirmed the validity of spheres as models of TICs for breast and prostate cancer as well as mesothelioma cell lines. Microarray data analysis revealed the Trp pathway as the only pathway upregulated significantly in all types of studied TICs, with increased levels of indoleamine-2,3-dioxygenase-1 (IDO1), the rate-limiting enzyme of Trp metabolism along the kynurenine pathway. All types of TICs also expressed higher levels of the Trp uptake system consisting of CD98 and LAT1 with functional consequences. IDO1 expression was regulated via both transcriptional and posttranscriptional mechanisms, depending on the cancer type. Serial transplantation of TICs in mice resulted in gradually increased IDO1. Mitocans, represented by α-tocopheryl succinate and mitochondrially targeted vitamin E succinate (MitoVES), suppressed IDO1 in TICs. MitoVES suppressed IDO1 in TICs with functional mitochondrial complex II, involving transcriptional and posttranscriptional mechanisms. IDO1 increase and its suppression by VE analogues were replicated in TICs from primary human glioblastomas. Our work indicates that IDO1 is increased in TICs and that mitocans suppress the protein.

• MeSH
• alfa-tokoferol farmakologie   MeSH
• antigeny CD98 genetika   metabolismus   MeSH
• antitumorózní látky fytogenní farmakologie   MeSH
• indolamin-2,3,-dioxygenasa genetika   metabolismus   MeSH
• kynurenin metabolismus   MeSH
• lidé MeSH
• metabolické sítě a dráhy účinky léků   genetika   MeSH
• mitochondrie účinky léků   metabolismus   MeSH
• nádorové buněčné linie MeSH
• nádorové kmenové buňky účinky léků   metabolismus   patologie   MeSH
• přenašeč velkých neutrálních aminokyselin 1 genetika   metabolismus   MeSH
• regulace genové exprese u nádorů * MeSH
• respirační komplex II genetika   metabolismus   MeSH
• signální transdukce MeSH
• tryptofan metabolismus   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Feochromocytomy a paragangliomy jsou nádory vznikající z chromafinních buněk, mohou metabolizovat, skladovat, ale ne vždy vylučovat katecholaminy. Typickými projevy feochromocytomu nebo paragangliomu jsou hypertenze (trvalá i záchvatovitá), palpitace, bolesti hlavy a pocení. Se vznikem těchto nádorů je dnes spojeno deset genů a předpokládá se, že další budou objeveny. Oba typy nádorů se vyskytují také v rámci genetických syndromů: syndromu familiární paragangliomatózy (geny SDH, SDHAF2), syndromu von Hippel-Lindau (gen VHL), syndromu mnohočetné endokrinní neoplazie typu 2 (gen RET) a neurofibromatózy typu 1 (gen NF1). U některých syndromů jsou tyto nádory prvním a jediným manifestovaným onemocněním. Některé typy mutací, především v genu SDHB, jsou spojeny s vysokým počtem maligních onemocnění, která jsou v současné době standardními postupy nevyléčitelná. Z těchto důvodů je nezbytné provádět genetické vyšetření nejen u pacienta, ale v celé rodině, a nabídnout nositelům mutací dlouhodobé nebo celoživotní sledování a případně včasnou léčbu. Péče o pacienty s těmito onemocněními proto vyžaduje multidisciplinární spolupráci a měla by být prováděna pouze ve specializovaných centrech, která mají s tímto druhem onemocnění dostatečné zkušenosti.

Pheochromocytomas and paragangliomas are tumors arising from chromaffin cells. These tumors produce catecholamines and are typically found with symptoms and signs that may include hypertension (persistent or episodic), palpitations, headache and sweating. So far, 10 different genes have been associated with both tumors and other genes are expected to be detected. Pheochromocytoma and paraganglioma can occur as a part of genetic syndromes – familial paragangliomas (SDH genes, SDHAF2 gene), von Hippel-Lindau syndrome (VHL gene), multiple endocrine neoplasia type 2 (RET gene), and neurofibromatosis type 1 (NF1 gene). These tumors may be the first and only manifestation of these genetic syndromes. Patients with SDHB mutations are at high risk to develop malignant disease and unfortunately current therapeutic options for malignant form of disease are poor. Genetic testing plays a key role in the management of these tumors and therefore not only index patients with pheochromocytoma but also relatives should be tested. Management of this disease requires multidisciplinary cooperation and should be performed in the specialized medical centres.

• Klíčová slova
• genetické vyšetření, sledování,
• MeSH
• biologické markery krev   MeSH
• bolesti hlavy MeSH
• chirurgie operační metody   využití   MeSH
• chromafinní buňky cytologie   patologie   MeSH
• diagnostické zobrazování metody   využití   MeSH
• feochromocytom diagnóza   genetika   terapie   MeSH
• financování organizované MeSH
• genetické nemoci vrozené diagnóza   genetika   prevence a kontrola   MeSH
• genetické testování MeSH
• hypertenze MeSH
• katecholaminy izolace a purifikace   škodlivé účinky   MeSH
• klinický obraz nemoci MeSH
• lidé MeSH
• paragangliom diagnóza   genetika   terapie   MeSH
• podjednotky proteinů MeSH
• pooperační péče MeSH
• preventivní lékařství MeSH
• respirační komplex II genetika   izolace a purifikace   MeSH
• sukcinátdehydrogenasa genetika   izolace a purifikace   MeSH
• Check Tag
• lidé MeSH