Chang 2018 Life Sciences Meeting 2018 Innsbruck AT

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pH dependence of mitochondrial respiration and H2O2 production in oral cancer cells – a pilot study.

Link:

Chang SC, Komlodi T, Dudas J, Gnaiger E (2018)

Event: Life Sciences Meeting 2018 Innsbruck AT

Cancers are characterized by a high metabolic plasticity resulting from mutations and the selection of metabolic phenotypes. Metabolic transformations involve mitochondrial adaptation or mitochondrial dysfunction. Metabolism and mitochondria have become focal targets for anticancer therapy. In the progression of tumor, cancer cells upregulate glucose uptake and glycolysis. The different environmental and intracellular pH due to the metabolic reprogramming can change the behavior of the cells. Therefore, we compared the effects of pH on mitochondrial respiration and H2O2 production in different cell lines.

We measured respiration and H2O2 production in permeabilized human embryonic kidney cells (HEK239T), human gingival fibroblasts (HGF) and human oral squamous carcinoma cancer cells (SCC25) in the pH range from 6.6 – 7.5 using high-resolution respirometry including the Amplex UltraRed assay. We used substrate-uncoupler-inhibitor titration protocols to access mitochondrial respiration in different coupling and pathway control states, activating the succinate (S)-, NADH- (N) and fatty acid (F)- pathways separately or in combination.

With increasing pH, H2O2 flux decreased in HEK239T cells in the S- and N-pathways, while O2 flux was significantly increased. A similar result was observed in HGF. Conversely, the SCC25 cells showed an opposite trend. In these cancer cells, electron transfer pathways and Complex IV activity were depressed at high pH. HGF and SCC25 showed a higher sensitivity to intracellular pH compared to HEK293T cells.

SCC25 cancer cells showed a response of respiration to changes in pH that was opposite compared to normal HGF and HEK293T cells. The sensitivity of mitochondrial respiration to modulations of intracellular pH may have implications on chemotherapy sensitivity. Therefore, the experimental design evaluated in the present study will be applied in radioresistant SCC25 cells and radiochemotherapy sensitive SCC-090 cells.


Bioblast editor: Chang SC O2k-Network Lab: AT Innsbruck Gnaiger E, AT Innsbruck Oroboros


Labels: MiParea: Respiration, Instruments;methods  Pathology: Cancer 

Organism: Human  Tissue;cell: Kidney, HEK  Preparation: Permeabilized cells 


Coupling state: LEAK, ROUTINE, OXPHOS, ET  Pathway: F, N, S, Gp, CIV, NS, Other combinations, ROX  HRR: Oxygraph-2k, O2k-Protocol, O2k-FluoRespirometer 

Amplex UltraRed, SUIT-009, SUIT-009 O2 pce D016, SUIT-009 AmR mt D021, SUIT-009 O2 mt D015, SUIT-009 AmR pce D019 

Affiliations

Chang SC(1), Komlodi T(1), Dudas J(3), Gnaiger E(1,2)
  1. Oroboros Instruments, Innsbruck, Austria. - shao.chang@oroboros.at
  2. Dept Visceral, Thoracic Surgery, Medical Univ Innsbruck, Austria
  3. Molecularbiological Oncological Research Group, Dept Otorhinolaryngology Head & Neck Surgery, Medical Univ Innsbruck, Austria