AMPK-ULK1-mediated autophagy confers resistance to BET inhibitor JQ1 in acute myeloid leukemia stem cells

Ji Eun Jang, Ju In Eom, Hoi Kyung Jeung, June Won Cheong, Jung Yeon Lee, Jin Seok Kim, Yoo Hong Min

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Purpose: Bromodomain and extraterminal domain (BET) inhibitors are promising epigenetic agents for the treatment of various subsets of acute myeloid leukemia (AML). However, the resistance of leukemia stem cells (LSC) to BET inhibitors remains a major challenge. In this study, we evaluated the mechanisms underlying LSC resistance to the BET inhibitor JQ1. Experimental Design: We evaluated the levels of apoptosis and autophagy induced by JQ1 in LSC-like leukemia cell lines and primary CD34+CD38-leukemic blasts obtained from AML cases with normal karyotype without recurrent mutations. Results: JQ1 effectively induced apoptosis in a concentrationdependent manner in JQ1-sensitive AML cells. However, in JQ1- resistant AML LSCs, JQ1 induced little apoptosis and led to upregulation of beclin-1, increased LC3-II lipidation, formation of autophagosomes, and downregulation of p62/SQSTM1. Inhibition of autophagy by pharmacologic inhibitors or knockdown of beclin-1 using specific siRNA enhanced JQ1-induced apoptosis in resistant cells, indicating that prosurvival autophagy occurred in these cells. Independent of mTOR signaling, activation of the AMPK (pThr172)/ULK1 (pSer555) pathway was found to be associated with JQ1-induced autophagy in resistant cells. AMPK inhibition using the pharmacologic inhibitor compound C or by knockdown of AMPKa suppressed autophagy and promoted JQ1-induced apoptosis in AML LSCs. Conclusions: These findings revealed that prosurvival autophagy was one of the mechanisms involved in the resistance AML LSCs to JQ1. Targeting the AMPK/ULK1 pathway or inhibition of autophagy could be an effective therapeutic strategy for combating resistance to BET inhibitors in AML and other types of cancer. Clin Cancer Res; 23(11); 2781-94.

Original languageEnglish
Pages (from-to)2781-2794
Number of pages14
JournalClinical Cancer Research
Volume23
Issue number11
DOIs
Publication statusPublished - 2017 Jun 1

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Myeloid Progenitor Cells
AMP-Activated Protein Kinases
Autophagy
Acute Myeloid Leukemia
Apoptosis
Leukemia
Stem Cells
Myeloid Cells
Karyotype
Epigenomics
Small Interfering RNA
Neoplasms
Research Design
Up-Regulation
Down-Regulation
Cell Line
Mutation

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research

Cite this

Jang, Ji Eun ; Eom, Ju In ; Jeung, Hoi Kyung ; Cheong, June Won ; Lee, Jung Yeon ; Kim, Jin Seok ; Min, Yoo Hong. / AMPK-ULK1-mediated autophagy confers resistance to BET inhibitor JQ1 in acute myeloid leukemia stem cells. In: Clinical Cancer Research. 2017 ; Vol. 23, No. 11. pp. 2781-2794.
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abstract = "Purpose: Bromodomain and extraterminal domain (BET) inhibitors are promising epigenetic agents for the treatment of various subsets of acute myeloid leukemia (AML). However, the resistance of leukemia stem cells (LSC) to BET inhibitors remains a major challenge. In this study, we evaluated the mechanisms underlying LSC resistance to the BET inhibitor JQ1. Experimental Design: We evaluated the levels of apoptosis and autophagy induced by JQ1 in LSC-like leukemia cell lines and primary CD34+CD38-leukemic blasts obtained from AML cases with normal karyotype without recurrent mutations. Results: JQ1 effectively induced apoptosis in a concentrationdependent manner in JQ1-sensitive AML cells. However, in JQ1- resistant AML LSCs, JQ1 induced little apoptosis and led to upregulation of beclin-1, increased LC3-II lipidation, formation of autophagosomes, and downregulation of p62/SQSTM1. Inhibition of autophagy by pharmacologic inhibitors or knockdown of beclin-1 using specific siRNA enhanced JQ1-induced apoptosis in resistant cells, indicating that prosurvival autophagy occurred in these cells. Independent of mTOR signaling, activation of the AMPK (pThr172)/ULK1 (pSer555) pathway was found to be associated with JQ1-induced autophagy in resistant cells. AMPK inhibition using the pharmacologic inhibitor compound C or by knockdown of AMPKa suppressed autophagy and promoted JQ1-induced apoptosis in AML LSCs. Conclusions: These findings revealed that prosurvival autophagy was one of the mechanisms involved in the resistance AML LSCs to JQ1. Targeting the AMPK/ULK1 pathway or inhibition of autophagy could be an effective therapeutic strategy for combating resistance to BET inhibitors in AML and other types of cancer. Clin Cancer Res; 23(11); 2781-94.",
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AMPK-ULK1-mediated autophagy confers resistance to BET inhibitor JQ1 in acute myeloid leukemia stem cells. / Jang, Ji Eun; Eom, Ju In; Jeung, Hoi Kyung; Cheong, June Won; Lee, Jung Yeon; Kim, Jin Seok; Min, Yoo Hong.

In: Clinical Cancer Research, Vol. 23, No. 11, 01.06.2017, p. 2781-2794.

Research output: Contribution to journalArticle

TY - JOUR

T1 - AMPK-ULK1-mediated autophagy confers resistance to BET inhibitor JQ1 in acute myeloid leukemia stem cells

AU - Jang, Ji Eun

AU - Eom, Ju In

AU - Jeung, Hoi Kyung

AU - Cheong, June Won

AU - Lee, Jung Yeon

AU - Kim, Jin Seok

AU - Min, Yoo Hong

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N2 - Purpose: Bromodomain and extraterminal domain (BET) inhibitors are promising epigenetic agents for the treatment of various subsets of acute myeloid leukemia (AML). However, the resistance of leukemia stem cells (LSC) to BET inhibitors remains a major challenge. In this study, we evaluated the mechanisms underlying LSC resistance to the BET inhibitor JQ1. Experimental Design: We evaluated the levels of apoptosis and autophagy induced by JQ1 in LSC-like leukemia cell lines and primary CD34+CD38-leukemic blasts obtained from AML cases with normal karyotype without recurrent mutations. Results: JQ1 effectively induced apoptosis in a concentrationdependent manner in JQ1-sensitive AML cells. However, in JQ1- resistant AML LSCs, JQ1 induced little apoptosis and led to upregulation of beclin-1, increased LC3-II lipidation, formation of autophagosomes, and downregulation of p62/SQSTM1. Inhibition of autophagy by pharmacologic inhibitors or knockdown of beclin-1 using specific siRNA enhanced JQ1-induced apoptosis in resistant cells, indicating that prosurvival autophagy occurred in these cells. Independent of mTOR signaling, activation of the AMPK (pThr172)/ULK1 (pSer555) pathway was found to be associated with JQ1-induced autophagy in resistant cells. AMPK inhibition using the pharmacologic inhibitor compound C or by knockdown of AMPKa suppressed autophagy and promoted JQ1-induced apoptosis in AML LSCs. Conclusions: These findings revealed that prosurvival autophagy was one of the mechanisms involved in the resistance AML LSCs to JQ1. Targeting the AMPK/ULK1 pathway or inhibition of autophagy could be an effective therapeutic strategy for combating resistance to BET inhibitors in AML and other types of cancer. Clin Cancer Res; 23(11); 2781-94.

AB - Purpose: Bromodomain and extraterminal domain (BET) inhibitors are promising epigenetic agents for the treatment of various subsets of acute myeloid leukemia (AML). However, the resistance of leukemia stem cells (LSC) to BET inhibitors remains a major challenge. In this study, we evaluated the mechanisms underlying LSC resistance to the BET inhibitor JQ1. Experimental Design: We evaluated the levels of apoptosis and autophagy induced by JQ1 in LSC-like leukemia cell lines and primary CD34+CD38-leukemic blasts obtained from AML cases with normal karyotype without recurrent mutations. Results: JQ1 effectively induced apoptosis in a concentrationdependent manner in JQ1-sensitive AML cells. However, in JQ1- resistant AML LSCs, JQ1 induced little apoptosis and led to upregulation of beclin-1, increased LC3-II lipidation, formation of autophagosomes, and downregulation of p62/SQSTM1. Inhibition of autophagy by pharmacologic inhibitors or knockdown of beclin-1 using specific siRNA enhanced JQ1-induced apoptosis in resistant cells, indicating that prosurvival autophagy occurred in these cells. Independent of mTOR signaling, activation of the AMPK (pThr172)/ULK1 (pSer555) pathway was found to be associated with JQ1-induced autophagy in resistant cells. AMPK inhibition using the pharmacologic inhibitor compound C or by knockdown of AMPKa suppressed autophagy and promoted JQ1-induced apoptosis in AML LSCs. Conclusions: These findings revealed that prosurvival autophagy was one of the mechanisms involved in the resistance AML LSCs to JQ1. Targeting the AMPK/ULK1 pathway or inhibition of autophagy could be an effective therapeutic strategy for combating resistance to BET inhibitors in AML and other types of cancer. Clin Cancer Res; 23(11); 2781-94.

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