1. Pyruvate carboxylase is critical for non-small-cell lung cancer proliferation.
- Author
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Sellers K, Fox MP, Bousamra M 2nd, Slone SP, Higashi RM, Miller DM, Wang Y, Yan J, Yuneva MO, Deshpande R, Lane AN, and Fan TW
- Subjects
- Animals, Carcinoma, Non-Small-Cell Lung genetics, Carcinoma, Non-Small-Cell Lung pathology, Citric Acid Cycle genetics, Female, Glucose metabolism, Glutathione biosynthesis, Glutathione genetics, HEK293 Cells, Humans, Lipid Metabolism genetics, Lung Neoplasms genetics, Lung Neoplasms pathology, Male, Mice, Neoplasm Proteins genetics, Nucleotides biosynthesis, Nucleotides genetics, Pyruvate Carboxylase genetics, Radioactive Tracers, Carcinoma, Non-Small-Cell Lung enzymology, Cell Proliferation, Gene Expression Regulation, Enzymologic, Gene Expression Regulation, Neoplastic, Lung Neoplasms enzymology, Neoplasm Proteins biosynthesis, Pyruvate Carboxylase biosynthesis
- Abstract
Anabolic biosynthesis requires precursors supplied by the Krebs cycle, which in turn requires anaplerosis to replenish precursor intermediates. The major anaplerotic sources are pyruvate and glutamine, which require the activity of pyruvate carboxylase (PC) and glutaminase 1 (GLS1), respectively. Due to their rapid proliferation, cancer cells have increased anabolic and energy demands; however, different cancer cell types exhibit differential requirements for PC- and GLS-mediated pathways for anaplerosis and cell proliferation. Here, we infused patients with early-stage non-small-cell lung cancer (NSCLC) with uniformly 13C-labeled glucose before tissue resection and determined that the cancerous tissues in these patients had enhanced PC activity. Freshly resected paired lung tissue slices cultured in 13C6-glucose or 13C5,15N2-glutamine tracers confirmed selective activation of PC over GLS in NSCLC. Compared with noncancerous tissues, PC expression was greatly enhanced in cancerous tissues, whereas GLS1 expression showed no trend. Moreover, immunohistochemical analysis of paired lung tissues showed PC overexpression in cancer cells rather than in stromal cells of tumor tissues. PC knockdown induced multinucleation, decreased cell proliferation and colony formation in human NSCLC cells, and reduced tumor growth in a mouse xenograft model. Growth inhibition was accompanied by perturbed Krebs cycle activity, inhibition of lipid and nucleotide biosynthesis, and altered glutathione homeostasis. These findings indicate that PC-mediated anaplerosis in early-stage NSCLC is required for tumor survival and proliferation.
- Published
- 2015
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