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Article: A Splice Variant of NCOR2, BQ323636.1, Confers Chemoresistance in Breast Cancer by Altering the Activity of NRF2

TitleA Splice Variant of NCOR2, BQ323636.1, Confers Chemoresistance in Breast Cancer by Altering the Activity of NRF2
Authors
Keywordssplice variant BQ
chemoresistance
breast cancer
NRF2
NCOR2
Issue Date2020
PublisherMDPI AG. The Journal's web site is located at http://www.mdpi.com/journal/cancers/
Citation
Cancers, 2020, v. 12 n. 3, p. article no. 533 How to Cite?
AbstractBreast cancer is the most common type of female cancer. Reactive oxygen species (ROS) are vital in regulating signaling pathways that control cell survival and cell proliferation. Chemotherapeutic drugs such as anthracyclines induce cell death via ROS induction. Chemoresistance development is associated with adaptive response to oxidative stress. NRF2 is the main regulator of cytoprotective response to oxidative stress. NRF2 can enhance cell growth, antioxidant expression, and chemoresistance by providing growth advantage for malignant cells. Previously, we identified BQ323636.1 (BQ), a novel splice variant of nuclear co-repressor NCOR2, which can robustly predict tamoxifen resistance in primary breast cancer. In this study, we found that BQ was overexpressed in epirubicin-resistant cells and demonstrated that BQ overexpression could reduce the levels of epirubicin-induced ROS and confer epirubicin resistance. In vivo analysis using tissue microarray of primary breast cancer showed direct correlation between BQ expression and chemoresistance. In vitro experiments showed BQ could modulate NRF2 transcriptional activity and upregulate antioxidants. Luciferase reporter assays showed that although NCOR2 repressed the transcriptional activity of NRF2, the presence of BQ reduced this repressive activity. Co-immunoprecipitation confirmed that NCOR2 could bind to NRF2 and that this interaction was compromised by BQ overexpression, leading to increased transcriptional activity in NRF2. Our findings suggest BQ can regulate the NRF2 signaling pathway via interference with NCOR2 suppressive activity and reveals a novel role for BQ as a modulator of chemoresistance in breast cancer.
Descriptioneid_2-s2.0-85079833114
Persistent Identifierhttp://hdl.handle.net/10722/287186
ISSN
2018 Impact Factor: 6.162
2015 SCImago Journal Rankings: 1.630
PubMed Central ID

 

DC FieldValueLanguage
dc.contributor.authorLeung, MH-
dc.contributor.authorTsoi, H-
dc.contributor.authorGong, C-
dc.contributor.authorMan, EPS-
dc.contributor.authorZona, S-
dc.contributor.authorYao, S-
dc.contributor.authorLam, EWF-
dc.contributor.authorKhoo, US-
dc.date.accessioned2020-09-22T02:57:07Z-
dc.date.available2020-09-22T02:57:07Z-
dc.date.issued2020-
dc.identifier.citationCancers, 2020, v. 12 n. 3, p. article no. 533-
dc.identifier.issn2072-6694-
dc.identifier.urihttp://hdl.handle.net/10722/287186-
dc.descriptioneid_2-s2.0-85079833114-
dc.description.abstractBreast cancer is the most common type of female cancer. Reactive oxygen species (ROS) are vital in regulating signaling pathways that control cell survival and cell proliferation. Chemotherapeutic drugs such as anthracyclines induce cell death via ROS induction. Chemoresistance development is associated with adaptive response to oxidative stress. NRF2 is the main regulator of cytoprotective response to oxidative stress. NRF2 can enhance cell growth, antioxidant expression, and chemoresistance by providing growth advantage for malignant cells. Previously, we identified BQ323636.1 (BQ), a novel splice variant of nuclear co-repressor NCOR2, which can robustly predict tamoxifen resistance in primary breast cancer. In this study, we found that BQ was overexpressed in epirubicin-resistant cells and demonstrated that BQ overexpression could reduce the levels of epirubicin-induced ROS and confer epirubicin resistance. In vivo analysis using tissue microarray of primary breast cancer showed direct correlation between BQ expression and chemoresistance. In vitro experiments showed BQ could modulate NRF2 transcriptional activity and upregulate antioxidants. Luciferase reporter assays showed that although NCOR2 repressed the transcriptional activity of NRF2, the presence of BQ reduced this repressive activity. Co-immunoprecipitation confirmed that NCOR2 could bind to NRF2 and that this interaction was compromised by BQ overexpression, leading to increased transcriptional activity in NRF2. Our findings suggest BQ can regulate the NRF2 signaling pathway via interference with NCOR2 suppressive activity and reveals a novel role for BQ as a modulator of chemoresistance in breast cancer.-
dc.languageeng-
dc.publisherMDPI AG. The Journal's web site is located at http://www.mdpi.com/journal/cancers/-
dc.relation.ispartofCancers-
dc.rightsThis work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.-
dc.subjectsplice variant BQ-
dc.subjectchemoresistance-
dc.subjectbreast cancer-
dc.subjectNRF2-
dc.subjectNCOR2-
dc.titleA Splice Variant of NCOR2, BQ323636.1, Confers Chemoresistance in Breast Cancer by Altering the Activity of NRF2-
dc.typeArticle-
dc.identifier.emailLeung, MH: mhl2018@hku.hk-
dc.identifier.emailTsoi, H: tsoiho@hku.hk-
dc.identifier.emailMan, EPS: ellenman@hku.hk-
dc.identifier.emailKhoo, US: uskhoo@hku.hk-
dc.identifier.authorityKhoo, US=rp00362-
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.3390/cancers12030533-
dc.identifier.pmid32110852-
dc.identifier.pmcidPMC7139508-
dc.identifier.scopuseid_2-s2.0-85079833114-
dc.identifier.hkuros314318-
dc.identifier.volume12-
dc.identifier.issue3-
dc.identifier.spagearticle no. 533-
dc.identifier.epagearticle no. 533-
dc.publisher.placeSwitzerland-

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