Bastos Sant'Anna Silva 2018 TRANSMIT Bertinoro di Romagna IT

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Cellular succinate transport and mitochondrial respiratory function in prostate cancer.

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Sant'Anna-Silva ACB, Klocker H, Weber A, Elmer E, Meszaros AT, Gnaiger E (2018)

Event: Course in Cancer Metabolism Bologna IT

Succinate dehydrogenase (SDH, mitochondrial Complex II) links the oxidation of succinate and FAD to fumarate and FADH2 in the tricarboxylic acid (TCA) cycle to electron transfer (ET) from FADH2 to ubiquinone in the ET system. Changes in ET capacity through the succinate pathway affect TCA cycle function and cell respiration [1]. In addition, succinate transmits oncogenic signals from mitochondria to the cytosol by stabilization of hypoxia inducible factor 1α. This, in turn, stimulates the expression of genes involved in angiogenesis and anaerobic metabolism [2], finally enabling tumour progression and metastasis. Succinate uptake is enhanced in various cancer cells [3], and its mitochondrial utilisation is increased in permeabilized prostate cancer cells [4]. To decipher the pathophysiological role of succinate in prostate cancer, we measured the plasma membrane permeability for succinate and utilization of external succinate by mitochondria in terms of succinate pathway capacity and kinetic properties in prostate cancer (multiple metastatic origins) and control cell lines. Respiration in RWPE-1 (prostate; noncancerous), LNCaP (prostate; lymph node metastasis) and DU145 (prostate; brain metastasis) cells was measured using high-resolution respirometry (O2k, Oroboros Instruments) and substrate-uncoupler-inhibitor titration (SUIT) protocols developed specifically for the study. To assess succinate utilization in intact cells independent of a plasma membrane succinate transporter, we applied novel plasma membrane-permeable succinate prodrugs (pS) [5]. In LNCaP cells, transport of external succinate is enhanced through the plasma membrane as compared to the other cell lines, while pS exerted similar effects in all cell lines, suggesting an important regulatory role of the transport mechanism. Furthermore, in LNCaP cells, mitochondria utilize succinate with higher affinity than control cells. Importantly, kinetic measurements demonstrated the most pronounced difference in the affinities in the physiological intracellular succinate concentration range (< 100 µM), underlining its pathophysiological role. Our results indicate a “succinate phenotype” in LNCaP, with enhanced transport and utilization. As such, succinate is a potential mitochondrial metabolic biomarker in prostate cancer cells. We propose a model in which succinate does not only play a role in the signalling but has a central role in the maintenance of mitochondrial respiration as a fuel substrate.

Keywords: mitochondrial respiration, intact cells, cell-permeable succinate, Prostate cancer, Succinate Bioblast editor: Sant'Anna-Silva ACB O2k-Network Lab: AT Innsbruck Gnaiger E, AT Innsbruck Oroboros, SE Lund Elmer E


Labels: MiParea: Respiration, Pharmacology;toxicology  Pathology: Cancer 

Organism: Human  Tissue;cell: Genital, HEK  Preparation: Intact cells, Permeabilized cells  Enzyme: Complex II;succinate dehydrogenase  Regulation: Ion;substrate transport, Substrate  Coupling state: LEAK, ROUTINE, OXPHOS, ET  Pathway: S, ROX  HRR: Oxygraph-2k, O2k-Protocol  Event: Oral 


Affiliations

Sant´Anna-Silva ACB(1,2), Klocker H(3), Weber A(3), Elmer E(4), Meszaros AT(1,2), Gnaiger E(1,2)
  1. Oroboros Instruments, Innsbruck, Austria. - ana.bastos@oroboros.at
  2. Daniel Swarovsky Inst, Medical Univ Innsbruck, Austria
  3. Dept of Urology, Medical Univ Innsbruck, Austria
  4. Dept of Clinical Sciences, Lund Univ, Sweden