Autophagy inhibition enhances vorinostat-induced apoptosis via ubiquitinated protein accumulation

Jennifer S. Carew, Ernest C. Medina, Juan A. Esquivel, Devalingam Mahalingam, Ronan T Swords, Kevin Kelly, Hui Zhang, Peng Huang, Alain C. Mita, Monica M. Mita, Francis J. Giles, Steffan T. Nawrocki

Research output: Contribution to journalArticle

140 Citations (Scopus)

Abstract

Autophagy is an evolutionarily conserved cell survival pathway that enables cells to recoup ATP and other critical biosynthetic molecules during nutrient deprivation or exposure to hypoxia, which are hallmarks of the tumour microenvironment. Autophagy has been implicated as a potential mechanism of resistance to anticancer agents as it can promote cell survival in the face of stress induced by chemotherapeutic agents by breaking down cellular components to generate alternative sources of energy. Disruption of autophagy with chloroquine (CQ) induces the accumulation of ubiquitin-conjugated proteins in a manner similar to the proteasome inhibitor bortezomib (BZ). However, CQ-induced protein accumulation occurs at a slower rate and is localized to lysosomes in contrast to BZ, which stimulates rapid buildup of ubiquitinated proteins and aggresome formation in the cytosol. The histone deacetylase (HDAC) inhibitor vorinostat (VOR) blocked BZ-induced aggresome formation, but promoted CQ-mediated ubiquitinated protein accumulation. Disruption of autophagy with CQ strongly enhanced VOR-mediated apoptosis in colon cancer cells. Accordingly, knockdown of the essential autophagy gene Atg7 also sensitized cells to VOR-induced apoptosis. Knockdown of HDAC6 greatly enhanced BZ-induced apoptosis, but only marginally sensitized cells to CQ. Subsequent studies determined that the CQ/VOR combination promoted a large increase in superoxide generation that was required for ubiquitinated protein accumulation and cell death. Finally, treatment with the CQ/VOR combination significantly reduced tumour burden and induced apoptosis in a colon cancer xenograft model. Collectively, our results establish that inhibition of autophagy with CQ induces ubiquitinated protein accumulation and VOR potentiates CQ-mediated aggregate formation, superoxide generation and apoptosis.

Original languageEnglish
Pages (from-to)2448-2459
Number of pages12
JournalJournal of Cellular and Molecular Medicine
Volume14
Issue number10
DOIs
StatePublished - Oct 1 2010
Externally publishedYes

Fingerprint

Ubiquitinated Proteins
Autophagy
Chloroquine
Apoptosis
Superoxides
Colonic Neoplasms
Cell Survival
vorinostat
Proteasome Inhibitors
Histone Deacetylase Inhibitors
Tumor Microenvironment
Essential Genes
Ubiquitin
Lysosomes
Tumor Burden
Heterografts
Antineoplastic Agents
Cytosol
Proteins
Cell Death

Keywords

  • Aggresome
  • Apoptosis
  • Autophagy
  • Bortezomib
  • Cancer
  • Chloroquine
  • Histone deacetylase
  • Proteasome
  • Superoxide

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Medicine

Cite this

Carew, J. S., Medina, E. C., Esquivel, J. A., Mahalingam, D., Swords, R. T., Kelly, K., ... Nawrocki, S. T. (2010). Autophagy inhibition enhances vorinostat-induced apoptosis via ubiquitinated protein accumulation. Journal of Cellular and Molecular Medicine, 14(10), 2448-2459. https://doi.org/10.1111/j.1582-4934.2009.00832.x

Autophagy inhibition enhances vorinostat-induced apoptosis via ubiquitinated protein accumulation. / Carew, Jennifer S.; Medina, Ernest C.; Esquivel, Juan A.; Mahalingam, Devalingam; Swords, Ronan T; Kelly, Kevin; Zhang, Hui; Huang, Peng; Mita, Alain C.; Mita, Monica M.; Giles, Francis J.; Nawrocki, Steffan T.

In: Journal of Cellular and Molecular Medicine, Vol. 14, No. 10, 01.10.2010, p. 2448-2459.

Research output: Contribution to journalArticle

Carew, JS, Medina, EC, Esquivel, JA, Mahalingam, D, Swords, RT, Kelly, K, Zhang, H, Huang, P, Mita, AC, Mita, MM, Giles, FJ & Nawrocki, ST 2010, 'Autophagy inhibition enhances vorinostat-induced apoptosis via ubiquitinated protein accumulation', Journal of Cellular and Molecular Medicine, vol. 14, no. 10, pp. 2448-2459. https://doi.org/10.1111/j.1582-4934.2009.00832.x
Carew, Jennifer S. ; Medina, Ernest C. ; Esquivel, Juan A. ; Mahalingam, Devalingam ; Swords, Ronan T ; Kelly, Kevin ; Zhang, Hui ; Huang, Peng ; Mita, Alain C. ; Mita, Monica M. ; Giles, Francis J. ; Nawrocki, Steffan T. / Autophagy inhibition enhances vorinostat-induced apoptosis via ubiquitinated protein accumulation. In: Journal of Cellular and Molecular Medicine. 2010 ; Vol. 14, No. 10. pp. 2448-2459.
@article{d9e0772bf21447e498bfb14b1f3746fa,
title = "Autophagy inhibition enhances vorinostat-induced apoptosis via ubiquitinated protein accumulation",
abstract = "Autophagy is an evolutionarily conserved cell survival pathway that enables cells to recoup ATP and other critical biosynthetic molecules during nutrient deprivation or exposure to hypoxia, which are hallmarks of the tumour microenvironment. Autophagy has been implicated as a potential mechanism of resistance to anticancer agents as it can promote cell survival in the face of stress induced by chemotherapeutic agents by breaking down cellular components to generate alternative sources of energy. Disruption of autophagy with chloroquine (CQ) induces the accumulation of ubiquitin-conjugated proteins in a manner similar to the proteasome inhibitor bortezomib (BZ). However, CQ-induced protein accumulation occurs at a slower rate and is localized to lysosomes in contrast to BZ, which stimulates rapid buildup of ubiquitinated proteins and aggresome formation in the cytosol. The histone deacetylase (HDAC) inhibitor vorinostat (VOR) blocked BZ-induced aggresome formation, but promoted CQ-mediated ubiquitinated protein accumulation. Disruption of autophagy with CQ strongly enhanced VOR-mediated apoptosis in colon cancer cells. Accordingly, knockdown of the essential autophagy gene Atg7 also sensitized cells to VOR-induced apoptosis. Knockdown of HDAC6 greatly enhanced BZ-induced apoptosis, but only marginally sensitized cells to CQ. Subsequent studies determined that the CQ/VOR combination promoted a large increase in superoxide generation that was required for ubiquitinated protein accumulation and cell death. Finally, treatment with the CQ/VOR combination significantly reduced tumour burden and induced apoptosis in a colon cancer xenograft model. Collectively, our results establish that inhibition of autophagy with CQ induces ubiquitinated protein accumulation and VOR potentiates CQ-mediated aggregate formation, superoxide generation and apoptosis.",
keywords = "Aggresome, Apoptosis, Autophagy, Bortezomib, Cancer, Chloroquine, Histone deacetylase, Proteasome, Superoxide",
author = "Carew, {Jennifer S.} and Medina, {Ernest C.} and Esquivel, {Juan A.} and Devalingam Mahalingam and Swords, {Ronan T} and Kevin Kelly and Hui Zhang and Peng Huang and Mita, {Alain C.} and Mita, {Monica M.} and Giles, {Francis J.} and Nawrocki, {Steffan T.}",
year = "2010",
month = "10",
day = "1",
doi = "10.1111/j.1582-4934.2009.00832.x",
language = "English",
volume = "14",
pages = "2448--2459",
journal = "Journal of Cellular and Molecular Medicine",
issn = "1582-1838",
publisher = "Wiley-Blackwell",
number = "10",

}

TY - JOUR

T1 - Autophagy inhibition enhances vorinostat-induced apoptosis via ubiquitinated protein accumulation

AU - Carew, Jennifer S.

AU - Medina, Ernest C.

AU - Esquivel, Juan A.

AU - Mahalingam, Devalingam

AU - Swords, Ronan T

AU - Kelly, Kevin

AU - Zhang, Hui

AU - Huang, Peng

AU - Mita, Alain C.

AU - Mita, Monica M.

AU - Giles, Francis J.

AU - Nawrocki, Steffan T.

PY - 2010/10/1

Y1 - 2010/10/1

N2 - Autophagy is an evolutionarily conserved cell survival pathway that enables cells to recoup ATP and other critical biosynthetic molecules during nutrient deprivation or exposure to hypoxia, which are hallmarks of the tumour microenvironment. Autophagy has been implicated as a potential mechanism of resistance to anticancer agents as it can promote cell survival in the face of stress induced by chemotherapeutic agents by breaking down cellular components to generate alternative sources of energy. Disruption of autophagy with chloroquine (CQ) induces the accumulation of ubiquitin-conjugated proteins in a manner similar to the proteasome inhibitor bortezomib (BZ). However, CQ-induced protein accumulation occurs at a slower rate and is localized to lysosomes in contrast to BZ, which stimulates rapid buildup of ubiquitinated proteins and aggresome formation in the cytosol. The histone deacetylase (HDAC) inhibitor vorinostat (VOR) blocked BZ-induced aggresome formation, but promoted CQ-mediated ubiquitinated protein accumulation. Disruption of autophagy with CQ strongly enhanced VOR-mediated apoptosis in colon cancer cells. Accordingly, knockdown of the essential autophagy gene Atg7 also sensitized cells to VOR-induced apoptosis. Knockdown of HDAC6 greatly enhanced BZ-induced apoptosis, but only marginally sensitized cells to CQ. Subsequent studies determined that the CQ/VOR combination promoted a large increase in superoxide generation that was required for ubiquitinated protein accumulation and cell death. Finally, treatment with the CQ/VOR combination significantly reduced tumour burden and induced apoptosis in a colon cancer xenograft model. Collectively, our results establish that inhibition of autophagy with CQ induces ubiquitinated protein accumulation and VOR potentiates CQ-mediated aggregate formation, superoxide generation and apoptosis.

AB - Autophagy is an evolutionarily conserved cell survival pathway that enables cells to recoup ATP and other critical biosynthetic molecules during nutrient deprivation or exposure to hypoxia, which are hallmarks of the tumour microenvironment. Autophagy has been implicated as a potential mechanism of resistance to anticancer agents as it can promote cell survival in the face of stress induced by chemotherapeutic agents by breaking down cellular components to generate alternative sources of energy. Disruption of autophagy with chloroquine (CQ) induces the accumulation of ubiquitin-conjugated proteins in a manner similar to the proteasome inhibitor bortezomib (BZ). However, CQ-induced protein accumulation occurs at a slower rate and is localized to lysosomes in contrast to BZ, which stimulates rapid buildup of ubiquitinated proteins and aggresome formation in the cytosol. The histone deacetylase (HDAC) inhibitor vorinostat (VOR) blocked BZ-induced aggresome formation, but promoted CQ-mediated ubiquitinated protein accumulation. Disruption of autophagy with CQ strongly enhanced VOR-mediated apoptosis in colon cancer cells. Accordingly, knockdown of the essential autophagy gene Atg7 also sensitized cells to VOR-induced apoptosis. Knockdown of HDAC6 greatly enhanced BZ-induced apoptosis, but only marginally sensitized cells to CQ. Subsequent studies determined that the CQ/VOR combination promoted a large increase in superoxide generation that was required for ubiquitinated protein accumulation and cell death. Finally, treatment with the CQ/VOR combination significantly reduced tumour burden and induced apoptosis in a colon cancer xenograft model. Collectively, our results establish that inhibition of autophagy with CQ induces ubiquitinated protein accumulation and VOR potentiates CQ-mediated aggregate formation, superoxide generation and apoptosis.

KW - Aggresome

KW - Apoptosis

KW - Autophagy

KW - Bortezomib

KW - Cancer

KW - Chloroquine

KW - Histone deacetylase

KW - Proteasome

KW - Superoxide

UR - http://www.scopus.com/inward/record.url?scp=77958575758&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77958575758&partnerID=8YFLogxK

U2 - 10.1111/j.1582-4934.2009.00832.x

DO - 10.1111/j.1582-4934.2009.00832.x

M3 - Article

C2 - 19583815

AN - SCOPUS:77958575758

VL - 14

SP - 2448

EP - 2459

JO - Journal of Cellular and Molecular Medicine

JF - Journal of Cellular and Molecular Medicine

SN - 1582-1838

IS - 10

ER -