Dataset Information

Spheroid cancer stem cells display reprogrammed metabolism and obtain energy by actively running the tricarboxylic acid (TCA) cycle.

ABSTRACT: The Warburg effect is a metabolic hallmark of cancer cells; cancer cells, unlike normal cells, exclusively activate glycolysis, even in the presence of enough oxygen. On the other hand, intratumoral heterogeneity is currently of interest in cancer research, including that involving cancer stem cells (CSCs). In the present study, we attempted to gain an understanding of metabolism in CSCs that is distinct from that in non-CSCs. After forming spheroids from the OVTOKO (ovarian clear cell adenocarcinoma) and SiHa (cervical squamous cell carcinoma) cell lines, the metabolites of these cells were compared with the metabolites of cancer cells that were cultured in adherent plates. A principle components analysis clearly divided their metabolic features. Amino acids that participate in tricarboxylic acid (TCA) cycle reactions, such as serine and glutamine, were significantly increased in the spheroids. Indeed, spheroids from each cell line contained more total adenylates than did their corresponding cells in adherent cultures. This study demonstrated that cancer metabolism is not limited to aerobic glycolysis (i.e. the Warburg effect), but is flexible and context-dependent. In addition, activation of TCA cycles was suggested to be a metabolic feature of CSCs that was distinct from non-CSCs. The amino acid metabolic pathways discussed here are already considered as targets for cancer therapy, and they are additionally proposed as potential targets for CSC treatment.

SUBMITTER: Sato M

PROVIDER: S-EPMC5078095 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Background: In hypoxic tumors, positive feedback between oncogenic KRAS and HIF-1α involves impressive metabolic changes correlating with drug resistance and poor prognosis in colorectal cancer. Up to date, designed KRAS-targeting molecules do not show clear benefits in patient overall survival (POS) so pharmacological modulation of aberrant tricarboxylic acid (TCA) cycle in hypoxic cancer has been proposed as a metabolic vulnerability of KRAS-driven tumors. Methods: Annexin V-FITC and cell viability assays were carried out in order to verify vitamin C citotoxicity in KRAS mutant SW480 and DLD1 as well as in Immortalized Human Colonic Epithelial Cells (HCEC). HIF1a expression and activity were determined by western blot and functional analysis assays. HIF1a direct targets GLUT1 and PDK1 expression was checked using western blot and qRT-PCR. Inmunohistochemical assays were perfomed in tumors derived from murine xenografts in order to validate previous observations in vivo. Vitamin C dependent PDH expression and activity modulation were detected by western blot and colorimetric activity assays. Acetyl-Coa levels and citrate synthase activity were assessed using colorimetric/fluorometric activity assays. Mitochondrial membrane potential (Δψ) and cell ATP levels were assayed using fluorometric and luminescent test. Results: PDK-1 in KRAS mutant CRC cells and murine xenografts was downregulated using pharmacological doses of vitamin C through the proline hydroxylation (Pro402) of the Hypoxia inducible factor-1(HIF-1)α, correlating with decreased expression of the glucose transporter 1 (GLUT-1) in both models. Vitamin C induced remarkable ATP depletion, rapid mitochondrial Δψ dissipation and diminished pyruvate dehydrogenase E1-α phosphorylation at Serine 293, then boosting PDH and citrate synthase activity. Conclusion: We report a striking and previously non reported role of vitamin C in the regulation of the pyruvate dehydrogenase (PDH) activity, then modulating the TCA cycle and mitochondrial metabolism in KRAS mutant colon cancer. Potential impact of vitamin C in the clinical management of anti-EGFR chemoresistant colorectal neoplasias should be further considered.

Dataset Information

Spheroid cancer stem cells display reprogrammed metabolism and obtain energy by actively running the tricarboxylic acid (TCA) cycle.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets