The autophagy scaffold protein ALFY is critical for the granulocytic differentiation of AML cells

Sci Rep. 2017 Oct 11;7(1):12980. doi: 10.1038/s41598-017-12734-4.

Abstract

Acute myeloid leukemia (AML) is a malignancy of myeloid progenitor cells that are blocked in differentiation. Acute promyelocytic leukemia (APL) is a rare form of AML, which generally presents with a t(15;17) translocation causing expression of the fusion protein PML-RARA. Pharmacological doses of all-trans retinoic acid (ATRA) induce granulocytic differentiation of APL cells leading to cure rates of >80% if combined with conventional chemotherapy. Autophagy is a lysosomal degradation pathway for the removal of cytoplasmic content and recycling of macromolecules. ATRA induces autophagy in ATRA-sensitive AML and APL cells and autophagy inhibition attenuates ATRA-triggered differentiation. In this study, we aimed at identifying if the autophagy-linked FYVE-domain containing protein (ALFY/WDFY3) is involved in autophagic degradation of protein aggregates contributes to ATRA therapy-induced autophagy. We found that ALFY mRNA levels increase significantly during the course of ATRA-induced differentiation of APL and AML cell lines. Importantly ALFY depletion impairs ATRA-triggered granulocytic differentiation of these cells. In agreement with its function in aggrephagy, knockdown of ALFY results in reduced ATRA-induced proteolysis. Our data further suggest that PML-RARα is an autophagy substrate degraded with the help of ALFY. In summary, we present a crucial role for ALFY in retinoid triggered maturation of AML cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Autophagy* / drug effects
  • Autophagy-Related Proteins
  • Cell Differentiation* / drug effects
  • Cell Line, Tumor
  • Down-Regulation / drug effects
  • Down-Regulation / genetics
  • Gene Expression Regulation, Leukemic
  • HEK293 Cells
  • Humans
  • Leukemia, Myeloid, Acute / genetics
  • Leukemia, Myeloid, Acute / pathology*
  • Lysosomes / drug effects
  • Lysosomes / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • MicroRNAs / genetics
  • MicroRNAs / metabolism
  • Neutrophils / drug effects
  • Neutrophils / pathology
  • Proteolysis / drug effects
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Tretinoin / pharmacology
  • Up-Regulation / drug effects
  • Up-Regulation / genetics

Substances

  • Adaptor Proteins, Signal Transducing
  • Autophagy-Related Proteins
  • MIrn181 microRNA, human
  • Membrane Proteins
  • MicroRNAs
  • RNA, Messenger
  • Transcription Factors
  • WDFY3 protein, human
  • Tretinoin