Beta-Hydroxybutyrate Promotes Proliferation, Migration and Stemness in a Subpopulation of 5FU Treated SW480 Cells: Evidence for Metabolic Plasticity in Colon Cancer

Document Type : Research Articles

Authors

Department of Cellular and Molecular Nutrition, National Nutrition and Food Technology Research Institute, Faculty of Nutrition Science and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Abstract

Background: Beta-hydroxybutyrate (BHB) as a ketone body is the metabolic fuel in oxidative phosphorylation
pathway. So far the effects of BHB on the biology of tumor cells is contradictory. Therefore, we investigated the effect of
BHB on viability, metabolism, proliferation and migration of 5FU treated SW480 colon cancer cell line. Methods: we
treated the SW480 cells with IC50 dose of 5-fluorouracil (5FU) for 72 h to isolate a subpopulation of 5FU treated cells
that were resistant to it. Effects of BHB on cell viability was investigated by MTT assay. Measurement of oxygen
consumption rate (OCR) in parallel with extracellular acidification rate (ECAR) upon BHB treatment was used for
determination of metabolic profile of these cells. Investigating the relationship between metabolic phenotype and
the status of differentiation and stemness was done by analyzing the expression of PGC-1α, c-MYC, NANOG, ALPi
and KRT20 genes by qRT-PCR. Clonogenic and scratch assay were performed to determine the proliferation and
migration abilities of incubated with BHB compared to untreated cells. Results: BHB increased cell viability in SW480
and 5FU treated SW480 cells. The results showed a significantly decreased ECAR and increased OCR in both cell
types following BHB treatment reflecting the superiority of oxidative phosphorylation profile compared to glycolysis
in both cell types. Also, treatment with BHB increases the expression of genes normally associated with stemness
and mitochondrial biogenesis and decreases the expression of genes related to glycolytic program and differentiation
in 5FU treated cells. Self-renewal and migration potential of BHB treated cells increased significantly. Conclusion:
These findings suggest that BHB utilization via oxidative mitochondrial metabolism can fuel proliferation, migration
and stemness in 5FU treated SW480 colon cancer cells.

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