Figure 7. p-4E controls metabolic stress-induced cell death and transcriptomic heterogeneity.
Indicated CRC lines were subject to glutamine deprivation and analyzed. (A) Attached cells at 48 hr were visualized by crystal violet. (B) The indicated proteins were analyzed by western blotting. (C) Transcripts at 24 hr were analyzed by RT-PCR and normalized to respective cell line controls (Gln+, 1). (D) Venn diagram of Gln deprivation induced genes in three sensitive cell lines. Two fold or more, *p<0.05. (E) Reactome Pathway analysis of shared genes (Silva-Almeida et al., 2020) in (D). (F) A model of p-4E in CRC development. CRC drivers converge on increased p-4E (S209) and p-4E-BP1(S65/T70) to promote Myc- and ISR (p-eIF2a/ATF4)-dependent adaptation and AKT activation via increased glutamine (Gln) metabolism. Acute metabolic stress (i.e. Gln deprivation) disrupts adaptation and triggers crisis in such cells due to rapid loss of p-4E/4E-BP1 and Myc and hyperactivation of ISR and p-AKT, leading to increased cell death and transcriptional heterogeneity.
Figure 7—figure supplement 1. Glutamine deprivation leads to ISR hyperactivation in mutant KRAS/BRAF CRC cells.
