The retinoblastoma pathway is often inactivated in human tumors resulting in deregulated E2F activity that can induce both proliferation and cell death. Although the role of E2F in apoptosis is well characterized, little is known regarding its putative participation in other cell death pathways. We show here that activation of E2F1 upregulates the expression of four autophagy genes - microtubule-associated protein-1 light chain-3 (LC3), autophagy-related gene-1 (ATG1), ATG5 and damage-regulated autophagy modulator (DRAM). E2F1-mediated induction of LC3, ATG1 and DRAM is direct and indeed, endogenous E2F1 can be found bound to regions encompassing the promoters of these genes. Regulation of ATG5 by E2F1 is indirect. Importantly, we demonstrate that E2F1 activation enhances autophagy and conversely, reducing endogenous E2F1 expression inhibits DNA damage-induced autophagy. These studies identify E2F1 as a transcriptional regulator of autophagy, and for the first time establish a role for E2F1 in DNA damage-induced autophagy.
|Number of pages||5|
|State||Published - 14 Aug 2008|
Bibliographical noteFunding Information:
We are grateful to Dalia Hacohen for excellent technical assistance and Yehuda Brody for statistical analysis. We thank Zvulun Elazar for helpful discussions and reagents and Uri Nir for critical reading of the manuscript. This work was supported by grants from the Israel Science Foundation (ISF), The Israel Cancer Association and The Israeli Ministry of Health to DG.