Functional Impacts of the BRCA1-mTORC2 Interaction in Breast Cancer
Affiliation
Univ Arizona, Dept Immunobiol, Coll MedIssue Date
2019-11-23Keywords
BRCA1BRCT domain
DNA damage response
PRR5
RICTOR
SIN1
mTORC2 complex
protein-protein interactions
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MDPICitation
Krieger, K.L.; Hu, W.-F.; Ripperger, T.; Woods, N.T. Functional Impacts of the BRCA1-mTORC2 Interaction in Breast Cancer. Int. J. Mol. Sci. 2019, 20, 5876.Rights
Copyright © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
Deleterious mutations in Breast Cancer 1 (BRCA1) are associated with an increased risk of breast and ovarian cancer. Mutations in the tandem BRCA1 C-terminal (tBRCT) protein domain disrupt critical protein interactions required for the faithful repair of DNA through homologous recombination, which contributes to oncogenesis. Our studies have identified RICTOR, PRR5, and SIN1 subunits of the mammalian target of rapamycin complex 2 (mTORC2) as interacting partners with the tBRCT domain of BRCA1 leading to the disruption of the mTORC2 complex. However, the interplay between mTORC2 signaling and BRCA1 function in the DNA damage response (DDR) remains to be determined. In this study, we used protein interaction assays to determine the binary interactions between the tBRCT domain and mTORC2 subunits, evaluated the impact of mTOR inhibition on the transcriptional function of the tBRCT, evaluated the impact of mTOR signaling on BRCA1 recruitment to DNA damage-induced foci and determined the breast cancer cell line response to mTOR inhibition dependent upon BRCA1 expression and mutation. This study determined that PRR5, RICTOR, and SIN1 could each independently interact with the BRCA1 tBRCT. Inhibition of mTORC1, but not mTORC1/2, increases BRCA1 transcriptional activation activity. Treatment with pan-mTOR inhibitor PP242 diminishes DNA damage-induced γH2AX and BRCA1 foci formation. Breast cancer cells lacking expression of functional BRCA1 are more sensitive to mTOR inhibitors. These data suggest that mTOR signaling is required for BRCA1 response to DNA damage and breast cancer cells lacking BRCA1 are more sensitive to pan-mTOR inhibition. This work suggests chemotherapeutic strategies using mTOR inhibitors could be tailored for patients that lack functional BRCA1.Note
Open access journalISSN
1422-0067PubMed ID
31771139Version
Final published versionSponsors
United States Department of Health & Human Services National Institutes of Health (NIH) - USA [R21CA184996, P20GM121316, P30CA036727, T32CA009476]ae974a485f413a2113503eed53cd6c53
10.3390/ijms20235876
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Except where otherwise noted, this item's license is described as Copyright © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
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