Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-64674
Wanka, C; Brucker, D P; Bähr, O; Ronellenfitsch, M; Weller, M; Steinbach, J P; Rieger, J (2012). Synthesis of cytochrome c oxidase 2: a p53-dependent metabolic regulator that promotes respiratory function and protects glioma and colon cancer cells from hypoxia-induced cell death. Oncogene, 31(33):3764-3776.
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P53 has an important role in the processing of starvation signals. P53-dependent molecular mediators of the Warburg effect reduce glucose consumption and promote mitochondrial function. We therefore hypothesized that the retention of wild-type p53 characteristic of primary glioblastomas limits metabolic demands induced by deregulated signal transduction in the presence of hypoxia and nutrient depletion. Here we report that short hairpin RNA-mediated gene suppression of wild-type p53 or ectopic expression of mutant temperature-sensitive dominant-negative p53(V135A) increased glucose consumption and lactate production, decreased oxygen consumption and enhanced hypoxia-induced cell death in p53 wild-type human glioblastoma cells. Similarly, genetic knockout of p53 in HCT116 colon carcinoma cells resulted in reduced respiration and hypersensitivity towards hypoxia-induced cell death. Further, wild-type p53 gene silencing reduced the expression of synthesis of cytochrome c oxidase 2 (SCO2), an effector necessary for respiratory chain function. An SCO2 transgene reverted the metabolic phenotype and restored resistance towards hypoxia in p53-depleted and p53 mutant glioma cells in a rotenone-sensitive manner, demonstrating that this effect was dependent on intact oxidative phosphorylation. Supplementation with methyl-pyruvate, a mitochondrial substrate, rescued p53 wild-type but not p53 mutant cells from hypoxic cell death, demonstrating a p53-mediated selective aptitude to metabolize mitochondrial substrates. Further, SCO2 gene silencing in p53 wild-type glioma cells sensitized these cells towards hypoxia. Finally, lentiviral gene suppression of SCO2 significantly enhanced tumor necrosis in a subcutaneous HCT116 xenograft tumor model, compatible with impaired energy metabolism in these cells. These findings demonstrate that glioma and colon cancer cells with p53 wild-type status can skew the Warburg effect and thereby reduce their vulnerability towards tumor hypoxia in an SCO2-dependent manner. Targeting SCO2 may therefore represent a valuable strategy to enhance sensitivity towards hypoxia and may complement strategies targeting glucose metabolism.
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|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||04 Faculty of Medicine > University Hospital Zurich > Clinic for Neurology|
|DDC:||610 Medicine & health|
|Deposited On:||18 Sep 2012 09:37|
|Last Modified:||16 Dec 2013 10:11|
|Publisher:||Nature Publishing Group|
|Free access at:||Publisher DOI. An embargo period may apply.|
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