Inhibition of MCL-1 enhances lapatinib toxicity and overcomes lapatinib resistance via BAK-dependent autophagy

Aditi Pandya Martin, Clint Mitchell, Mohamed Rahmani, Kenneth Nephew, Steven Grant, Paul Dent

Research output: Contribution to journalArticle

69 Citations (Scopus)

Abstract

Prior studies demonstrated that resistance to the ERBB1/2 inhibitor Lapatinib in HCT116 cells was mediated by increased MCL-1 expression. We examined whether inhibition of BCL-2 family function could restore Lapatinib toxicity in Lapatinib adapted tumor cells and enhance Lapatinib toxicity in naive cells. The BCL-2 family antagonist Obatoclax (GX15-070), that inhibits BCL-2/BCL-XL/MCL-1 function, enhanced Lapatinib toxicity in parental HCT116 and Lapatinib adapted HCT116 cells. In breast cancer lines, regardless of elevated ERRB1/2 expression, GX15-070 enhanced Lapatinib toxicity within 3-12 h. The promotion of Lapatinib toxicity neither correlated with cleavage of caspase 3 nor was blocked by inhibition caspases; and was not associated with changes in the activities of ERK1/2, JNK1/2 or p38 MAPK but with reduced AKT, mTOR and S6K1 phosphorylation. The promotion of Lapatinib toxicity by GX15-070 correlated with increased cytosolic levels of apoptosis inducing factor (AIF) and expression of ATG8 (LC3), and the formation of large vesicles that intensely stained for a transfected LC3-GFP construct. Knockdown of the autophagy regulatory proteins ATG5 or Beclin1 suppressed the induction of LC3-GFP vesicularization and significantly reduced cell killing, whereas knock down of MCL-1 and BCL-XL enhanced the induction of LC3-GFP vesicularization and significantly enhanced cell killing. Knockdown of Beclin1 and AIF abolished cell killing. collectively, our data demonstrate that Obatoclax mediated inhibition of MCL-1 rapidly enhances Lapatinib toxicity in tumor cells via a toxic form of autophagy and via AIF release from the mitochondrion.

Original languageEnglish
Pages (from-to)2084-2096
Number of pages13
JournalCancer Biology and Therapy
Volume8
Issue number21
StatePublished - Nov 1 2009

Fingerprint

Autophagy
Apoptosis Inducing Factor
HCT116 Cells
lapatinib
Poisons
p38 Mitogen-Activated Protein Kinases
Caspases
Caspase 3
Neoplasms
Mitochondria
Phosphorylation
obatoclax
Breast Neoplasms

Keywords

  • Autophagy
  • Cell death
  • Lapatinib
  • Obatoclax
  • Resistance

ASJC Scopus subject areas

  • Cancer Research
  • Oncology
  • Molecular Medicine
  • Pharmacology

Cite this

Inhibition of MCL-1 enhances lapatinib toxicity and overcomes lapatinib resistance via BAK-dependent autophagy. / Martin, Aditi Pandya; Mitchell, Clint; Rahmani, Mohamed; Nephew, Kenneth; Grant, Steven; Dent, Paul.

In: Cancer Biology and Therapy, Vol. 8, No. 21, 01.11.2009, p. 2084-2096.

Research output: Contribution to journalArticle

Martin, AP, Mitchell, C, Rahmani, M, Nephew, K, Grant, S & Dent, P 2009, 'Inhibition of MCL-1 enhances lapatinib toxicity and overcomes lapatinib resistance via BAK-dependent autophagy', Cancer Biology and Therapy, vol. 8, no. 21, pp. 2084-2096.
Martin, Aditi Pandya ; Mitchell, Clint ; Rahmani, Mohamed ; Nephew, Kenneth ; Grant, Steven ; Dent, Paul. / Inhibition of MCL-1 enhances lapatinib toxicity and overcomes lapatinib resistance via BAK-dependent autophagy. In: Cancer Biology and Therapy. 2009 ; Vol. 8, No. 21. pp. 2084-2096.
@article{64df53e9b0444fd3b22bdf93fbd1b135,
title = "Inhibition of MCL-1 enhances lapatinib toxicity and overcomes lapatinib resistance via BAK-dependent autophagy",
abstract = "Prior studies demonstrated that resistance to the ERBB1/2 inhibitor Lapatinib in HCT116 cells was mediated by increased MCL-1 expression. We examined whether inhibition of BCL-2 family function could restore Lapatinib toxicity in Lapatinib adapted tumor cells and enhance Lapatinib toxicity in naive cells. The BCL-2 family antagonist Obatoclax (GX15-070), that inhibits BCL-2/BCL-XL/MCL-1 function, enhanced Lapatinib toxicity in parental HCT116 and Lapatinib adapted HCT116 cells. In breast cancer lines, regardless of elevated ERRB1/2 expression, GX15-070 enhanced Lapatinib toxicity within 3-12 h. The promotion of Lapatinib toxicity neither correlated with cleavage of caspase 3 nor was blocked by inhibition caspases; and was not associated with changes in the activities of ERK1/2, JNK1/2 or p38 MAPK but with reduced AKT, mTOR and S6K1 phosphorylation. The promotion of Lapatinib toxicity by GX15-070 correlated with increased cytosolic levels of apoptosis inducing factor (AIF) and expression of ATG8 (LC3), and the formation of large vesicles that intensely stained for a transfected LC3-GFP construct. Knockdown of the autophagy regulatory proteins ATG5 or Beclin1 suppressed the induction of LC3-GFP vesicularization and significantly reduced cell killing, whereas knock down of MCL-1 and BCL-XL enhanced the induction of LC3-GFP vesicularization and significantly enhanced cell killing. Knockdown of Beclin1 and AIF abolished cell killing. collectively, our data demonstrate that Obatoclax mediated inhibition of MCL-1 rapidly enhances Lapatinib toxicity in tumor cells via a toxic form of autophagy and via AIF release from the mitochondrion.",
keywords = "Autophagy, Cell death, Lapatinib, Obatoclax, Resistance",
author = "Martin, {Aditi Pandya} and Clint Mitchell and Mohamed Rahmani and Kenneth Nephew and Steven Grant and Paul Dent",
year = "2009",
month = "11",
day = "1",
language = "English",
volume = "8",
pages = "2084--2096",
journal = "Cancer Biology and Therapy",
issn = "1538-4047",
publisher = "Landes Bioscience",
number = "21",

}

TY - JOUR

T1 - Inhibition of MCL-1 enhances lapatinib toxicity and overcomes lapatinib resistance via BAK-dependent autophagy

AU - Martin, Aditi Pandya

AU - Mitchell, Clint

AU - Rahmani, Mohamed

AU - Nephew, Kenneth

AU - Grant, Steven

AU - Dent, Paul

PY - 2009/11/1

Y1 - 2009/11/1

N2 - Prior studies demonstrated that resistance to the ERBB1/2 inhibitor Lapatinib in HCT116 cells was mediated by increased MCL-1 expression. We examined whether inhibition of BCL-2 family function could restore Lapatinib toxicity in Lapatinib adapted tumor cells and enhance Lapatinib toxicity in naive cells. The BCL-2 family antagonist Obatoclax (GX15-070), that inhibits BCL-2/BCL-XL/MCL-1 function, enhanced Lapatinib toxicity in parental HCT116 and Lapatinib adapted HCT116 cells. In breast cancer lines, regardless of elevated ERRB1/2 expression, GX15-070 enhanced Lapatinib toxicity within 3-12 h. The promotion of Lapatinib toxicity neither correlated with cleavage of caspase 3 nor was blocked by inhibition caspases; and was not associated with changes in the activities of ERK1/2, JNK1/2 or p38 MAPK but with reduced AKT, mTOR and S6K1 phosphorylation. The promotion of Lapatinib toxicity by GX15-070 correlated with increased cytosolic levels of apoptosis inducing factor (AIF) and expression of ATG8 (LC3), and the formation of large vesicles that intensely stained for a transfected LC3-GFP construct. Knockdown of the autophagy regulatory proteins ATG5 or Beclin1 suppressed the induction of LC3-GFP vesicularization and significantly reduced cell killing, whereas knock down of MCL-1 and BCL-XL enhanced the induction of LC3-GFP vesicularization and significantly enhanced cell killing. Knockdown of Beclin1 and AIF abolished cell killing. collectively, our data demonstrate that Obatoclax mediated inhibition of MCL-1 rapidly enhances Lapatinib toxicity in tumor cells via a toxic form of autophagy and via AIF release from the mitochondrion.

AB - Prior studies demonstrated that resistance to the ERBB1/2 inhibitor Lapatinib in HCT116 cells was mediated by increased MCL-1 expression. We examined whether inhibition of BCL-2 family function could restore Lapatinib toxicity in Lapatinib adapted tumor cells and enhance Lapatinib toxicity in naive cells. The BCL-2 family antagonist Obatoclax (GX15-070), that inhibits BCL-2/BCL-XL/MCL-1 function, enhanced Lapatinib toxicity in parental HCT116 and Lapatinib adapted HCT116 cells. In breast cancer lines, regardless of elevated ERRB1/2 expression, GX15-070 enhanced Lapatinib toxicity within 3-12 h. The promotion of Lapatinib toxicity neither correlated with cleavage of caspase 3 nor was blocked by inhibition caspases; and was not associated with changes in the activities of ERK1/2, JNK1/2 or p38 MAPK but with reduced AKT, mTOR and S6K1 phosphorylation. The promotion of Lapatinib toxicity by GX15-070 correlated with increased cytosolic levels of apoptosis inducing factor (AIF) and expression of ATG8 (LC3), and the formation of large vesicles that intensely stained for a transfected LC3-GFP construct. Knockdown of the autophagy regulatory proteins ATG5 or Beclin1 suppressed the induction of LC3-GFP vesicularization and significantly reduced cell killing, whereas knock down of MCL-1 and BCL-XL enhanced the induction of LC3-GFP vesicularization and significantly enhanced cell killing. Knockdown of Beclin1 and AIF abolished cell killing. collectively, our data demonstrate that Obatoclax mediated inhibition of MCL-1 rapidly enhances Lapatinib toxicity in tumor cells via a toxic form of autophagy and via AIF release from the mitochondrion.

KW - Autophagy

KW - Cell death

KW - Lapatinib

KW - Obatoclax

KW - Resistance

UR - http://www.scopus.com/inward/record.url?scp=73549101691&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=73549101691&partnerID=8YFLogxK

M3 - Article

VL - 8

SP - 2084

EP - 2096

JO - Cancer Biology and Therapy

JF - Cancer Biology and Therapy

SN - 1538-4047

IS - 21

ER -