The Transcription Factor E4F1 Coordinates CHK1-Dependent Checkpoint and Mitochondrial Functions

TL;DR

E4F1 is a key regulator that links mitochondrial function and DNA damage checkpoints, and its inactivation causes mitochondrial dysfunction and cell death in p53-deficient cancer cells, suggesting new therapeutic strategies.

Contribution

This study reveals that E4F1 directly controls mitochondrial and cell-cycle genes, coordinating survival pathways in p53-deficient cancer cells, which was not previously understood.

Findings

E4F1 directly regulates mitochondrial and checkpoint genes.

Inactivation of E4F1 causes mitochondrial dysfunction and increased ROS.

E4F1 inactivation leads to cell death in p53-deficient cells.

Abstract

Recent data support the notion that a group of key transcriptional regulators involved in tumorigenesis, including MYC, p53, E2F1, and BMI1, share an intriguing capacity to simultaneously regulate metabolism and cell cycle. Here, we show that another factor, the multifunctional protein E4F1, directly controls genes involved in mitochondria functions and cell-cycle checkpoints, including Chek1, a major component of the DNA damage response. Coordination of these cellular functions by E4F1 appears essential for the survival of p53-deficient transformed cells. Acute inactivation of E4F1 in these cells results in CHK1-dependent checkpoint deficiency and multiple mitochondrial dysfunctions that lead to increased ROS production, energy stress, and inhibition of de novo pyrimidine synthesis. This deadly cocktail leads to the accumulation of uncompensated oxidative damage to proteins and extensive DNA damage, ending in cell death. This supports the rationale of therapeutic strategies simultaneously targeting mitochondria and CHK1 for selective killing of p53-deficient cancer cells.