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Multi-omics Characterization of Acquired Olaparib Resistance in BRCA1 and BRCA2 Mutant Breast Cancer Cell Lines
Holda A Anagho-Mattanovich1, Meeli Mullari1, Matthias Anagho-Mattanovich2
1Department of Proteomics, Novo Nordisk Foundation Center for Protein Research, Institute for Cellular and Molecular Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Abstract:
Poly (ADP-ribose) polymerase inhibitors (PARPi) are widely used as targeted therapies against breast cancers with BRCA mutations. However, the development of resistance to PARPi poses a significant challenge for long-term efficacy of these therapies, warranting further understanding of mechanisms of PARPi resistance. Here, we generated and characterized Olaparib resistance in BRCA1/2 mutant breast cancer cell lines MDAMB436 and HCC1428 using a systems-level multi-omics approach, including transcriptome, proteome, phosphoproteome, and ADP-ribosylation analysis. Our analyses revealed that resistance development strongly correlated with protein expression changes, while modest effects on phosphorylation- and ADP-ribosylation-dependent signaling pathways were observed. We found that BRCA1 expression was reestablished in OR MDAMB436 cell lines, while PARP1 expression was decreased. In OR HCC1428 cell lines, the BRCA2 mutation was not reverted. However, we observed increased expression of Fanconi anemia group D2 (FANCD2), histone parylation factor 1 (HPF1), and Nicotinamide phosphoribosyltransferase (NAMPT) in various cell lines, suggesting increased replication fork protection, and changes in the ADPr pathway and adaptation of metabolic pathways as resistance mechanisms. Our findings provide valuable insights into the complex landscape of PARPi resistance, offering potential targets for further investigation and therapeutic intervention.
Insights
Poly (ADP-ribose) polymerase inhibitors (PARPi) resistance in breast cancer involves significant protein expression changes. Understanding these mechanisms, like BRCA1 re-establishment and FANCD2 upregulation, is key for improving targeted therapies.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Poly (ADP-ribose) polymerase inhibitors (PARPi) are crucial targeted therapies for BRCA-mutated breast cancers.
- Development of resistance to PARPi limits their long-term clinical efficacy.
- Understanding PARPi resistance mechanisms is essential for improving treatment outcomes.
Purpose of the Study:
- To investigate the molecular mechanisms underlying Olaparib resistance in BRCA1/2-mutant breast cancer cell lines.
- To characterize changes in cellular pathways and protein expression associated with PARPi resistance.
Main Methods:
- Generation and characterization of Olaparib-resistant breast cancer cell lines (MDAMB436, HCC1428).
- Application of a systems-level multi-omics approach: transcriptome, proteome, phosphoproteome, and ADP-ribosylation analysis.
Main Results:
- Resistance development correlated strongly with protein expression changes, with less impact on phosphorylation and ADP-ribosylation signaling.
- BRCA1 expression was restored in resistant MDAMB436 cells, accompanied by decreased PARP1 expression.
- Resistant HCC1428 cells showed no BRCA2 mutation reversion but increased FANCD2, HPF1, and NAMPT expression, indicating enhanced replication fork protection and metabolic pathway adaptation.
Conclusions:
- Protein expression alterations are central to PARPi resistance in breast cancer.
- Mechanisms include BRCA1 re-expression, PARP1 downregulation, FANCD2/HPF1 upregulation, and metabolic pathway adaptations.
- These findings offer potential new targets for overcoming PARPi resistance.
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