Time- and cell-resolved dynamics of redox-sensitive Nrf2, HIF and NF-κB activities in 3D spheroids enriched for cancer stem cells.
Cancer cells have an altered redox status, with changes in intracellular signaling pathways. The knowledge of how such processes are regulated in 3D spheroids, being well-established tumor models, is limited. To approach this question we stably transfected HCT116 cells with a pTRAF reporter that enabled time- and cell-resolved activity monitoring of three redox-regulated transcription factors Nrf2, HIF and NF-κB in spheroids enriched for cancer stem cells. At the first day of spheroid formation, these transcription factors were activated and thereafter became repressed. After about a week, both HIF and Nrf2 were reactivated within the spheroid cores. Further amplifying HIF activation in spheroids by treatment with DMOG resulted in a dominant quiescent stem-cell-like phenotype, with high resistance to stress-inducing treatments. Auranofin, triggering oxidative stress and Nrf2 activation, had opposite effects with increased differentiation and proliferation. These novel high-resolution insights into spatiotemporal activation patterns demonstrate a striking coordination of redox regulated transcription factors within spheroids not occurring in conventional cell culture models.
Institute of Nutrition, Department of Molecular Nutrition Physiology, Friedrich-Schiller-Universität Jena, Dornburgerstr. 24, 07743 Jena, Germany. Electronic address: anna.kipp@uni-jena.de.
Anna P
AP
Kipp
Department of Molecular Toxicology, German Institute of Human Nutrition, Potsdam-Rehbrücke, Arthur-Scheunert-Allee 114-116, 14558 Nuthetal, Germany.
Stefanie
S
Deubel
Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
Elias S J
ESJ
Arnér
Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden. Electronic address: katarina.johansson@ki.se.
Katarina
K
Johansson
D000600:Amino Acids, Dicarboxylic / Q000494:pharmacology; D018929:Cell Culture Techniques; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D045325:HCT116 Cells; D006801:Humans; D051793:Hypoxia-Inducible Factor 1 / Q000235:genetics*; D008954:Models, Biological; D051267:NF-E2-Related Factor 2 / Q000235:genetics*; D016328:NF-kappa B / Q000235:genetics*; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism*; D010084:Oxidation-Reduction; D018874:Spheroids, Cellular / Q000187:drug effects / Q000378:metabolism*; D015533:Transcriptional Activation
D000600:Amino Acids, Dicarboxylic; D051793:Hypoxia-Inducible Factor 1; D051267:NF-E2-Related Factor 2; D016328:NF-kappa B; C495635:NFE2L2 protein, human; C040947:oxalylglycine
Cancer stem cells; HIF; NF-κB; Nrf2; Redox regulation; Spheroids