Metabolic resistance to the inhibition of mitochondrial transcription revealed by CRISPR-Cas9 screen.
Mara MennuniRoberta FilogranaAndrea FelserNina A BonekampPatrick GiavaliscoOleksandr LytovchenkoNils-Göran LarssonPublished in: EMBO reports (2021)
Cancer cells depend on mitochondria to sustain their increased metabolic need and mitochondria therefore constitute possible targets for cancer treatment. We recently developed small-molecule inhibitors of mitochondrial transcription (IMTs) that selectively impair mitochondrial gene expression. IMTs have potent antitumor properties in vitro and in vivo, without affecting normal tissues. Because therapy-induced resistance is a major constraint to successful cancer therapy, we investigated mechanisms conferring resistance to IMTs. We employed a CRISPR-Cas9 (clustered regularly interspaced short palindromic repeats)-(CRISP-associated protein 9) whole-genome screen to determine pathways conferring resistance to acute IMT1 treatment. Loss of genes belonging to von Hippel-Lindau (VHL) and mammalian target of rapamycin complex 1 (mTORC1) pathways caused resistance to acute IMT1 treatment and the relevance of these pathways was confirmed by chemical modulation. We also generated cells resistant to chronic IMT treatment to understand responses to persistent mitochondrial gene expression impairment. We report that IMT1-acquired resistance occurs through a compensatory increase of mitochondrial DNA (mtDNA) expression and cellular metabolites. We found that mitochondrial transcription factor A (TFAM) downregulation and inhibition of mitochondrial translation impaired survival of resistant cells. The identified susceptibility and resistance mechanisms to IMTs may be relevant for different types of mitochondria-targeted therapies.
Keyphrases
- gene expression
- oxidative stress
- crispr cas
- mitochondrial dna
- transcription factor
- small molecule
- induced apoptosis
- liver failure
- cancer therapy
- dna methylation
- copy number
- stem cells
- signaling pathway
- genome editing
- high throughput
- drug induced
- cell proliferation
- diabetic rats
- mesenchymal stem cells
- drug delivery
- bone marrow
- mass spectrometry
- reactive oxygen species
- single cell
- combination therapy
- ms ms
- cell cycle arrest
- replacement therapy
- free survival