Autophagy induction causes a synthetic lethal sensitization to ribonucleotide reductase inhibition in breast cancer cells

Yun Ru Chen, Brittany Tsou, Shuya Hu, Huimin Ma, Xiyong Liu, Yun Yen, David K. Ann

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Macroautophagy can promote cellular survival or death depending on the cellular context and its extent. We hypothesized that autophagy induction would synergize with a therapeutic agent targeting the autophagic cargo. To test this hypothesis, we treated breast cancer MDA-MB-231 cells with tamoxifen (TMX), which induces autophagy through an estrogen receptor-independent pathway. Induction of autophagy reduced cellular levels of RRM2, a subunit of ribonucleotide reductase (RR), the rate limiting enzyme in the production of deoxyribonucleotide triphosphates (dNTPs). This autophagy inducer was combined with COH29, an inhibitor developed in our laboratory that targets RR through a novel mechanism. The combination therapy showed synergistic effects on cytotoxicity in vitro and in an in vivo xenograft model. This cytotoxicity was blocked by knockdown of the autophagy protein ATG5 or addition of chloroquine, an autophagy inhibitor. The combined therapy also induced dNTP depletion and massive genomic instability, leading us to hypothesize that combining autophagy induction with RR inhibition can lead to mitotic catastrophe in rapidly dividing cells. We propose that this TMX + COH29 combined therapy may have clinical benefit. Furthermore, autophagy induction may be a general mechanism for augmenting the effects of chemotherapeutic agents.

Original languageEnglish
Pages (from-to)1984-1999
Number of pages16
JournalOncotarget
Volume7
Issue number2
DOIs
Publication statusPublished - Jan 1 2016
Externally publishedYes

Fingerprint

Ribonucleotide Reductases
Autophagy
Breast Neoplasms
Deoxyribonucleotides
Tamoxifen
Genomic Instability
Chloroquine
Therapeutics
Heterografts
Estrogen Receptors

Keywords

  • Autophagy
  • Breast cancer
  • Ribonucleotide reductase
  • Synthetic lethality
  • Tamoxifen

ASJC Scopus subject areas

  • Oncology

Cite this

Autophagy induction causes a synthetic lethal sensitization to ribonucleotide reductase inhibition in breast cancer cells. / Chen, Yun Ru; Tsou, Brittany; Hu, Shuya; Ma, Huimin; Liu, Xiyong; Yen, Yun; Ann, David K.

In: Oncotarget, Vol. 7, No. 2, 01.01.2016, p. 1984-1999.

Research output: Contribution to journalArticle

Chen, Yun Ru ; Tsou, Brittany ; Hu, Shuya ; Ma, Huimin ; Liu, Xiyong ; Yen, Yun ; Ann, David K. / Autophagy induction causes a synthetic lethal sensitization to ribonucleotide reductase inhibition in breast cancer cells. In: Oncotarget. 2016 ; Vol. 7, No. 2. pp. 1984-1999.
@article{5ab4c961be324acb951b475eba03c1b6,
title = "Autophagy induction causes a synthetic lethal sensitization to ribonucleotide reductase inhibition in breast cancer cells",
abstract = "Macroautophagy can promote cellular survival or death depending on the cellular context and its extent. We hypothesized that autophagy induction would synergize with a therapeutic agent targeting the autophagic cargo. To test this hypothesis, we treated breast cancer MDA-MB-231 cells with tamoxifen (TMX), which induces autophagy through an estrogen receptor-independent pathway. Induction of autophagy reduced cellular levels of RRM2, a subunit of ribonucleotide reductase (RR), the rate limiting enzyme in the production of deoxyribonucleotide triphosphates (dNTPs). This autophagy inducer was combined with COH29, an inhibitor developed in our laboratory that targets RR through a novel mechanism. The combination therapy showed synergistic effects on cytotoxicity in vitro and in an in vivo xenograft model. This cytotoxicity was blocked by knockdown of the autophagy protein ATG5 or addition of chloroquine, an autophagy inhibitor. The combined therapy also induced dNTP depletion and massive genomic instability, leading us to hypothesize that combining autophagy induction with RR inhibition can lead to mitotic catastrophe in rapidly dividing cells. We propose that this TMX + COH29 combined therapy may have clinical benefit. Furthermore, autophagy induction may be a general mechanism for augmenting the effects of chemotherapeutic agents.",
keywords = "Autophagy, Breast cancer, Ribonucleotide reductase, Synthetic lethality, Tamoxifen",
author = "Chen, {Yun Ru} and Brittany Tsou and Shuya Hu and Huimin Ma and Xiyong Liu and Yun Yen and Ann, {David K.}",
year = "2016",
month = "1",
day = "1",
doi = "10.18632/oncotarget.6539",
language = "English",
volume = "7",
pages = "1984--1999",
journal = "Oncotarget",
issn = "1949-2553",
publisher = "Impact Journals LLC",
number = "2",

}

TY - JOUR

T1 - Autophagy induction causes a synthetic lethal sensitization to ribonucleotide reductase inhibition in breast cancer cells

AU - Chen, Yun Ru

AU - Tsou, Brittany

AU - Hu, Shuya

AU - Ma, Huimin

AU - Liu, Xiyong

AU - Yen, Yun

AU - Ann, David K.

PY - 2016/1/1

Y1 - 2016/1/1

N2 - Macroautophagy can promote cellular survival or death depending on the cellular context and its extent. We hypothesized that autophagy induction would synergize with a therapeutic agent targeting the autophagic cargo. To test this hypothesis, we treated breast cancer MDA-MB-231 cells with tamoxifen (TMX), which induces autophagy through an estrogen receptor-independent pathway. Induction of autophagy reduced cellular levels of RRM2, a subunit of ribonucleotide reductase (RR), the rate limiting enzyme in the production of deoxyribonucleotide triphosphates (dNTPs). This autophagy inducer was combined with COH29, an inhibitor developed in our laboratory that targets RR through a novel mechanism. The combination therapy showed synergistic effects on cytotoxicity in vitro and in an in vivo xenograft model. This cytotoxicity was blocked by knockdown of the autophagy protein ATG5 or addition of chloroquine, an autophagy inhibitor. The combined therapy also induced dNTP depletion and massive genomic instability, leading us to hypothesize that combining autophagy induction with RR inhibition can lead to mitotic catastrophe in rapidly dividing cells. We propose that this TMX + COH29 combined therapy may have clinical benefit. Furthermore, autophagy induction may be a general mechanism for augmenting the effects of chemotherapeutic agents.

AB - Macroautophagy can promote cellular survival or death depending on the cellular context and its extent. We hypothesized that autophagy induction would synergize with a therapeutic agent targeting the autophagic cargo. To test this hypothesis, we treated breast cancer MDA-MB-231 cells with tamoxifen (TMX), which induces autophagy through an estrogen receptor-independent pathway. Induction of autophagy reduced cellular levels of RRM2, a subunit of ribonucleotide reductase (RR), the rate limiting enzyme in the production of deoxyribonucleotide triphosphates (dNTPs). This autophagy inducer was combined with COH29, an inhibitor developed in our laboratory that targets RR through a novel mechanism. The combination therapy showed synergistic effects on cytotoxicity in vitro and in an in vivo xenograft model. This cytotoxicity was blocked by knockdown of the autophagy protein ATG5 or addition of chloroquine, an autophagy inhibitor. The combined therapy also induced dNTP depletion and massive genomic instability, leading us to hypothesize that combining autophagy induction with RR inhibition can lead to mitotic catastrophe in rapidly dividing cells. We propose that this TMX + COH29 combined therapy may have clinical benefit. Furthermore, autophagy induction may be a general mechanism for augmenting the effects of chemotherapeutic agents.

KW - Autophagy

KW - Breast cancer

KW - Ribonucleotide reductase

KW - Synthetic lethality

KW - Tamoxifen

UR - http://www.scopus.com/inward/record.url?scp=84957677338&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84957677338&partnerID=8YFLogxK

U2 - 10.18632/oncotarget.6539

DO - 10.18632/oncotarget.6539

M3 - Article

C2 - 26675256

AN - SCOPUS:84957677338

VL - 7

SP - 1984

EP - 1999

JO - Oncotarget

JF - Oncotarget

SN - 1949-2553

IS - 2

ER -