E2F-1 lacking the transcriptional activity domain induces autophagy

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Mapping the Structure-Function Relationships of Disordered Oncogenic Transcription Factors Using Transcriptomic Analysis
09:58

Mapping the Structure-Function Relationships of Disordered Oncogenic Transcription Factors Using Transcriptomic Analysis

Published on: June 27, 2020

Aracely Garcia-Garcia1, Humberto Rodriguez-Rocha, Michael T Tseng

  • 1Department of Surgery, James Graham Brown Cancer Center, Louisville, KY, USA.

Cancer Biology & Therapy
|July 25, 2012
PubMed

Insights

The transcription factor E2F-1 and its truncated form (E2Ftr) effectively induce autophagy and apoptosis, leading to cancer cell death. This autophagy induction by E2Ftr offers a promising strategy against treatment-resistant tumors.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Cancer Research

Background:

  • The transcription factor E2F-1 is vital for cell proliferation control.
  • E2F-1 exhibits tumor-suppressive functions through apoptosis and autophagy induction.

Purpose of the Study:

  • To compare the autophagy-inducing capabilities of E2F-1 and its truncated form (E2Ftr), which lacks the transactivation domain (TAD).

Main Methods:

  • Gaussia luciferase-based assays to measure autophagic marker LC3 cleavage.
  • Western blotting to assess LC3 and autophagy protein 5 (Atg5) upregulation.
  • Confocal microscopy for GFP-tagged LC3 puncta formation and transmission electron microscopy (TEM) for autophagosome visualization.
  • Cell viability assays using caspase inhibitor (z-VAD-fmk) and Atg5 knockout cells.

Main Results:

  • Both E2F-1 and E2Ftr induced LC3 cleavage, LC3 and Atg5 upregulation, and autophagosome formation (GFP-LC3 puncta, TEM).
  • E2F-1 and E2Ftr mediated cytotoxicity was partially inhibited by z-VAD-fmk and significantly reduced in Atg5 knockout cells.
  • The TAD of E2F-1 is not essential for autophagy induction.

Conclusions:

  • Apoptosis and autophagy synergize for effective cancer cell killing by E2F-1 and E2Ftr.
  • E2Ftr-induced autophagy presents a potential therapeutic avenue for overcoming conventional treatment resistance in tumors.

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