BCR-ABL suppresses autophagy through ATF5-mediated regulation of mTOR transcription
Document Type
Journal ArticlePublication Date
2011-06-29Keywords
Fusion Proteins, bcr-ablActivating Transcription Factors
TOR Serine-Threonine Kinases
Autophagy
Genetics and Genomics
Metadata
Show full item recordAbstract
The oncoprotein BCR-ABL transforms myeloid progenitor cells and is responsible for the development of chronic myeloid leukemia (CML). In transformed cells, BCR-ABL suppresses apoptosis as well as autophagy, a catabolic process in which cellular components are degraded by the lysosomal machinery. The mechanism by which BCR-ABL suppresses autophagy is not known. Here we report that in both mouse and human BCR-ABL-transformed cells, activating transcription factor 5 (ATF5), a pro-survival factor, suppresses autophagy but does not affect apoptosis. We find that BCR-ABL, through phosphoinositide-3-kinase (PI3K)/AKT/FOXO4 signaling, transcriptionally upregulates ATF5 expression and that ATF5, in turn, stimulates transcription of mammalian target of rapamycin (mTOR; also called mechanistic target of rapamycin), a well-established master negative-regulator of autophagy. Previous studies have shown that the BCR-ABL inhibitor imatinib mesylate induces both apoptosis and autophagy, and that the resultant autophagy modulates the efficiency by which imatinib kills BCR-ABL-transformed cells. We demonstrate that imatinib-induced autophagy is due to inhibition of the BCR-ABL/PI3K/AKT/FOXO4/ATF5/mTOR pathway that we have identified in this study.Source
Blood. 2011 Jun 29. Link to article on publisher's siteDOI
10.1182/blood-2010-12-322537Permanent Link to this Item
http://hdl.handle.net/20.500.14038/43957PubMed ID
21715304Related Resources
Link to Article in PubMedae974a485f413a2113503eed53cd6c53
10.1182/blood-2010-12-322537