Fine-tuning the metabolic rewiring and adaptation of translational machinery during an epithelial-mesenchymal transition in breast cancer cells

Abstract

Background: During breast cancer progression, the epithelial to mesenchymal transition has been associated with metastasis and endocrine therapy resistance; however, the underlying mechanisms remain elusive. To gain insight into this process, we studied the transition undergone by MCF7-derived cells, which is driven by the constitutive nuclear expression of a MKL1 variant devoid of the actin-binding domain (MKL1 ΔN200). We characterized the adaptive changes that occur during the MKL1-induced cellular model and focused on regulation of translation machinery and metabolic adaptation. Methods: We performed a genome-wide analysis at the transcriptional and translational level using ribosome profiling complemented with RNA-Seq and analyzed the expression of components of the translation machinery and enzymes involved in energy metabolism. NGS data were correlated with metabolomic measurements and quantification of specific mRNAs extracted from polysomes and western blots. Results: Our results reveal the expression profiles of a luminal to basal-like state in accordance with an epithelial to mesenchymal transition. During the transition, the synthesis of ribosomal proteins and that of many translational factors was upregulated. This overexpression of the translational machinery appears to be regulated at the translational level. Our results indicate an increase of ribosome biogenesis and translation activity. We detected an extensive metabolic rewiring occurring in an already "Warburg-like" context, in which enzyme isoform switches and metabolic shunts indicate a crucial role of HIF-1α along with other master regulatory factors. Furthermore, we detected a decrease in the expression of enzymes involved in ribonucleotide synthesis from the pentose phosphate pathway. During this transition, cells increase in size, downregulate genes associated with proliferation, and strongly upregulate expression of cytoskeletal and extracellular matrix genes.

Ready to migrate? Reading cellular signs of migration in an epithelial to mesenchymal transition model

“…We recently reported that EMT-like MKL1 ΔN200 cells show extensive molecular and biochemical modifications (Fernández-Calero et al, 2020). Indeed, our transcriptomic and translatomic results suggest a general boost in translation that could be sustained by the significant increase in the expression and activity of several components of the protein synthesis machinery and translation-associated factors (Fig.…”

“…In addition, MKL1 ΔN200 cells display deep metabolic rewiring consistent with an enhanced Warburg-like effect characterized by impairment of Tricarboxylic Acid Cycle (TCA), rise of glucose consumption and glycolysis, flux redirection towards oxidative steps of the Pentose Phosphate Pathway (Fig. 1) (Fernández-Calero et al, 2020). This behavior was also detected in different cellular models of EMT (Kondaveeti et al, 2015;Liu et al, 2016;Morandi et al, 2017;Martínez-Reyes and Chandel, 2020).…”

“…Indeed, our transcriptomic and translatomic results suggest a general boost in translation that could be sustained by the significant increase in the expression and activity of several components of the protein synthesis machinery and translation-associated factors (Fig. 1) (Fernández-Calero et al, 2020). Higher ribosome biogenesis was previously detected in other EMT cellular models, such as non transformed mouse mammary gland epithelial NMuMG and MMTV-PyMT mouse-derived Py2T mammary cell lines treated with TGFβ, and MCF7 cells cultured under hypoxic conditions, as well as in Wnt-driven EMT delamination and migration of neural crest cells in chick and mouse embryonic development (Prakash et al, 2019).…”

Transcriptomic and metabolomic profiling reveal the p53-dependent benzeneacetic acid attenuation of silica‐induced epithelial–mesenchymal transition in human bronchial epithelial cells

“…Metabolic adaption is an adaptive change occurring during the cells in response to silica under the p53-existing or deficiency status. The final goal of this adaptive change is to achieve a new homeostatic status and maximize the opportunity for cell survival [ 32 ]. In total, 42 metabolites changed significantly in HBE p53-KO cells compared with p53-wt cells ( p < 0.05), of which 22 were upregulated and 20 were downregulated.…”

Transcriptomic and Metabolomic Profiling Reveal the p53-Dependent Benzeneacetic Acid Attenuation of Silica-Induced Epithelial–Mesenchymal Transition in Human Bronchial Epithelial Cells

“…Metabolic adaption is an adaptive change occurring during the cells in response to silica under the p53-existing or de ciency status. The nal goal of this adaptive change is to achieve a new homeostatic status and maximize the opportunity for cell survival [32]. In total, 42 metabolites changed signi cantly in HBE p53-KO cells compared with p53-wt cells (p < 0.05), of which 22 were upregulated and 20 were downregulated.…”