Bastos Sant'Anna Silva 2019 Life Sciences Meeting 2019 Innsbruck AT

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Cellular succinate transport and mitochondrial respiratory function in prostate cancer.

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Sant'Anna-Silva ACB, Klocker H, Elmer E, Weber A, Gnaiger E, Meszaros AT (2019)

Event: Life Science PhD Meeting 2019 Innsbruck AT

Succinate dehydrogenase (SDH, mitochondrial Complex II) links the oxidation of succinate to fumarate and reduction of FAD to FADH2 in the tricarboxylic acid (TCA) cycle. Further electron transfer (ET) proceeds from FADH2 to ubiquinone in the ET system. Changes in ET capacity through the succinate pathway affect TCA cycle function and cell respiration. Succinate can accumulate in the mitochondria and be transported to the cytosol playing a role in stabilization of hypoxia inducible factor 1α, finally enabling tumour progression and metastasis. Succinate uptake is enhanced in various cancer cells and its mitochondrial utilisation is increased in permeabilized prostate cancer cells. To decipher the pathophysiological role of succinate in prostate cancer, we tested the utilization of external succinate by mitochondria in terms of succinate pathway capacity and kinetic properties in prostate cancer and control cell lines. Respiration in RWPE-1 (noncancerous), LNCaP (lymph node metastasis) and DU145 (brain metastasis) cells was measured using High-Resolution FluoRespirometry (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). 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, kinetic measurements demonstrated that in LNCaP cells, mitochondria utilize succinate with higher affinity than control cells, underlining its (patho)physiological role. Moreover, our results confirm that a lower extracellular pH can stimulate succinate utilization by mitochondria in LNCaP cells, possibly due to its interaction with the transporter, as previously described. 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 signalling but has a central role in the maintenance of mitochondrial respiration as a fuel substrate.

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


Labels: MiParea: Respiration  Pathology: Cancer 

Organism: Human  Tissue;cell: Genital  Preparation: Intact cells  Enzyme: Complex II;succinate dehydrogenase  Regulation: Ion;substrate transport  Coupling state: ROUTINE  Pathway: S, ROX  HRR: Oxygraph-2k, O2k-Protocol  Event: Poster  SUIT-010 O2 ce-pce D050 

Affiliations

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