The unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer

Sandra Van Schaeybroeck, Nicholas Forsythe, Alaa Refaat, Arman Javadi, Hajrah Khawaja, Jessica-Anne Weir, Heba Emam, Wendy Moore, Frank Burkamp, Vlad Popovici, Puthen Jithesh, Claudio Isella, Melissa LaBonte Wilson, Ian Mills, Patrick Johnston

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Background
BRAFV600E mutations occur in ~10% of colorectal cancer (CRC), are associated with poor survival and have limited responses to BRAF/MEK inhibition with or without EGFR inhibition. There is an unmet need to understand the biology of poor prognostic BRAFMT CRC.

Method
We have used differential gene expression and pathway analyses of untreated stage II and stage III BRAFMT (discovery set: n=31; validation set: n=26) CRC and an siRNA screen to characterize the biology underpinning the BRAFMT subgroup with poorest outcome.

Results
These analyses identified the unfolded protein response (UPR) as a novel and druggable pathway associated with the BRAFMT CRC subgroup with poorest outcome. We also found that oncogenic BRAF drives the endoplasmic reticulum (ER) stress pathway activation through MEK/ERK. Furthermore, inhibition of GRP78, the master regulator of the UPR, using siRNA or small molecule inhibition, resulted in acute ER stress and apoptosis, in particular in BRAFMT CRC cells. In addition, dual targeting of protein degradation using combined Carfilzomib (proteasome inhibitor) and ACY-1215 (HDAC6-selective inhibitor) treatment resulted in marked accumulation of protein aggregates, acute ER stress, apoptosis and therapeutic efficacy in BRAFMT in vitro and xenograft models. Mechanistically, we found that the apoptosis following combined Carfilzomib/ACY-1215 treatment is mediated through increased CHOP expression.

Conclusion
Taken together, our findings indicate that oncogenic BRAF induces chronic ER stress and that inducers of acute ER stress could be a novel treatment strategy for poor prognostic BRAFMT CRC.
Original languageEnglish
Title of host publicationThe unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer
PublisherNational Cancer Research Insitute
Publication statusPublished - 2017

Fingerprint

Unfolded Protein Response
Endoplasmic Reticulum Stress
Colorectal Neoplasms
Mitogen-Activated Protein Kinase Kinases
Apoptosis
Small Interfering RNA
Therapeutics
Proteasome Inhibitors
Heterografts
Proteolysis
Gene Expression
Mutation

Cite this

Van Schaeybroeck, S., Forsythe, N., Refaat, A., Javadi, A., Khawaja, H., Weir, J-A., ... Johnston, P. (2017). The unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer. In The unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer National Cancer Research Insitute.
Van Schaeybroeck, Sandra ; Forsythe, Nicholas ; Refaat, Alaa ; Javadi, Arman ; Khawaja, Hajrah ; Weir, Jessica-Anne ; Emam, Heba ; Moore, Wendy ; Burkamp, Frank ; Popovici, Vlad ; Jithesh, Puthen ; Isella, Claudio ; LaBonte Wilson, Melissa ; Mills, Ian ; Johnston, Patrick. / The unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer. The unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer. National Cancer Research Insitute, 2017.
@inproceedings{5689a1c5398e483589c6567eac708146,
title = "The unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer",
abstract = "BackgroundBRAFV600E mutations occur in ~10{\%} of colorectal cancer (CRC), are associated with poor survival and have limited responses to BRAF/MEK inhibition with or without EGFR inhibition. There is an unmet need to understand the biology of poor prognostic BRAFMT CRC. MethodWe have used differential gene expression and pathway analyses of untreated stage II and stage III BRAFMT (discovery set: n=31; validation set: n=26) CRC and an siRNA screen to characterize the biology underpinning the BRAFMT subgroup with poorest outcome. ResultsThese analyses identified the unfolded protein response (UPR) as a novel and druggable pathway associated with the BRAFMT CRC subgroup with poorest outcome. We also found that oncogenic BRAF drives the endoplasmic reticulum (ER) stress pathway activation through MEK/ERK. Furthermore, inhibition of GRP78, the master regulator of the UPR, using siRNA or small molecule inhibition, resulted in acute ER stress and apoptosis, in particular in BRAFMT CRC cells. In addition, dual targeting of protein degradation using combined Carfilzomib (proteasome inhibitor) and ACY-1215 (HDAC6-selective inhibitor) treatment resulted in marked accumulation of protein aggregates, acute ER stress, apoptosis and therapeutic efficacy in BRAFMT in vitro and xenograft models. Mechanistically, we found that the apoptosis following combined Carfilzomib/ACY-1215 treatment is mediated through increased CHOP expression.ConclusionTaken together, our findings indicate that oncogenic BRAF induces chronic ER stress and that inducers of acute ER stress could be a novel treatment strategy for poor prognostic BRAFMT CRC.",
author = "{Van Schaeybroeck}, Sandra and Nicholas Forsythe and Alaa Refaat and Arman Javadi and Hajrah Khawaja and Jessica-Anne Weir and Heba Emam and Wendy Moore and Frank Burkamp and Vlad Popovici and Puthen Jithesh and Claudio Isella and {LaBonte Wilson}, Melissa and Ian Mills and Patrick Johnston",
year = "2017",
language = "English",
booktitle = "The unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer",
publisher = "National Cancer Research Insitute",

}

Van Schaeybroeck, S, Forsythe, N, Refaat, A, Javadi, A, Khawaja, H, Weir, J-A, Emam, H, Moore, W, Burkamp, F, Popovici, V, Jithesh, P, Isella, C, LaBonte Wilson, M, Mills, I & Johnston, P 2017, The unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer. in The unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer. National Cancer Research Insitute.

The unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer. / Van Schaeybroeck, Sandra; Forsythe, Nicholas; Refaat, Alaa; Javadi, Arman; Khawaja, Hajrah; Weir, Jessica-Anne; Emam, Heba; Moore, Wendy; Burkamp, Frank; Popovici, Vlad; Jithesh, Puthen; Isella, Claudio; LaBonte Wilson, Melissa; Mills, Ian; Johnston, Patrick.

The unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer. National Cancer Research Insitute, 2017.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

TY - GEN

T1 - The unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer

AU - Van Schaeybroeck, Sandra

AU - Forsythe, Nicholas

AU - Refaat, Alaa

AU - Javadi, Arman

AU - Khawaja, Hajrah

AU - Weir, Jessica-Anne

AU - Emam, Heba

AU - Moore, Wendy

AU - Burkamp, Frank

AU - Popovici, Vlad

AU - Jithesh, Puthen

AU - Isella, Claudio

AU - LaBonte Wilson, Melissa

AU - Mills, Ian

AU - Johnston, Patrick

PY - 2017

Y1 - 2017

N2 - BackgroundBRAFV600E mutations occur in ~10% of colorectal cancer (CRC), are associated with poor survival and have limited responses to BRAF/MEK inhibition with or without EGFR inhibition. There is an unmet need to understand the biology of poor prognostic BRAFMT CRC. MethodWe have used differential gene expression and pathway analyses of untreated stage II and stage III BRAFMT (discovery set: n=31; validation set: n=26) CRC and an siRNA screen to characterize the biology underpinning the BRAFMT subgroup with poorest outcome. ResultsThese analyses identified the unfolded protein response (UPR) as a novel and druggable pathway associated with the BRAFMT CRC subgroup with poorest outcome. We also found that oncogenic BRAF drives the endoplasmic reticulum (ER) stress pathway activation through MEK/ERK. Furthermore, inhibition of GRP78, the master regulator of the UPR, using siRNA or small molecule inhibition, resulted in acute ER stress and apoptosis, in particular in BRAFMT CRC cells. In addition, dual targeting of protein degradation using combined Carfilzomib (proteasome inhibitor) and ACY-1215 (HDAC6-selective inhibitor) treatment resulted in marked accumulation of protein aggregates, acute ER stress, apoptosis and therapeutic efficacy in BRAFMT in vitro and xenograft models. Mechanistically, we found that the apoptosis following combined Carfilzomib/ACY-1215 treatment is mediated through increased CHOP expression.ConclusionTaken together, our findings indicate that oncogenic BRAF induces chronic ER stress and that inducers of acute ER stress could be a novel treatment strategy for poor prognostic BRAFMT CRC.

AB - BackgroundBRAFV600E mutations occur in ~10% of colorectal cancer (CRC), are associated with poor survival and have limited responses to BRAF/MEK inhibition with or without EGFR inhibition. There is an unmet need to understand the biology of poor prognostic BRAFMT CRC. MethodWe have used differential gene expression and pathway analyses of untreated stage II and stage III BRAFMT (discovery set: n=31; validation set: n=26) CRC and an siRNA screen to characterize the biology underpinning the BRAFMT subgroup with poorest outcome. ResultsThese analyses identified the unfolded protein response (UPR) as a novel and druggable pathway associated with the BRAFMT CRC subgroup with poorest outcome. We also found that oncogenic BRAF drives the endoplasmic reticulum (ER) stress pathway activation through MEK/ERK. Furthermore, inhibition of GRP78, the master regulator of the UPR, using siRNA or small molecule inhibition, resulted in acute ER stress and apoptosis, in particular in BRAFMT CRC cells. In addition, dual targeting of protein degradation using combined Carfilzomib (proteasome inhibitor) and ACY-1215 (HDAC6-selective inhibitor) treatment resulted in marked accumulation of protein aggregates, acute ER stress, apoptosis and therapeutic efficacy in BRAFMT in vitro and xenograft models. Mechanistically, we found that the apoptosis following combined Carfilzomib/ACY-1215 treatment is mediated through increased CHOP expression.ConclusionTaken together, our findings indicate that oncogenic BRAF induces chronic ER stress and that inducers of acute ER stress could be a novel treatment strategy for poor prognostic BRAFMT CRC.

M3 - Conference contribution

BT - The unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer

PB - National Cancer Research Insitute

ER -

Van Schaeybroeck S, Forsythe N, Refaat A, Javadi A, Khawaja H, Weir J-A et al. The unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer. In The unfolded protein response: a novel therapeutic target for poor prognostic BRAF mutant colorectal cancer. National Cancer Research Insitute. 2017