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Zikry TM, Wolff SC, Ranek JS, Davis HM, Naugle A, Luthra N, Whitman AA, Kedziora KM, Stallaert W, Kosorok MR, Spanheimer PM, Purvis JE. Cell cycle plasticity underlies fractional resistance to palbociclib in ER+/HER2- breast tumor cells. Proc Natl Acad Sci U S A 2024; 121:e2309261121. [PMID: 38324568 PMCID: PMC10873600 DOI: 10.1073/pnas.2309261121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 01/05/2024] [Indexed: 02/09/2024] Open
Abstract
The CDK4/6 inhibitor palbociclib blocks cell cycle progression in Estrogen receptor-positive, human epidermal growth factor 2 receptor-negative (ER+/HER2-) breast tumor cells. Despite the drug's success in improving patient outcomes, a small percentage of tumor cells continues to divide in the presence of palbociclib-a phenomenon we refer to as fractional resistance. It is critical to understand the cellular mechanisms underlying fractional resistance because the precise percentage of resistant cells in patient tissue is a strong predictor of clinical outcomes. Here, we hypothesize that fractional resistance arises from cell-to-cell differences in core cell cycle regulators that allow a subset of cells to escape CDK4/6 inhibitor therapy. We used multiplex, single-cell imaging to identify fractionally resistant cells in both cultured and primary breast tumor samples resected from patients. Resistant cells showed premature accumulation of multiple G1 regulators including E2F1, retinoblastoma protein, and CDK2, as well as enhanced sensitivity to pharmacological inhibition of CDK2 activity. Using trajectory inference approaches, we show how plasticity among cell cycle regulators gives rise to alternate cell cycle "paths" that allow individual tumor cells to escape palbociclib treatment. Understanding drivers of cell cycle plasticity, and how to eliminate resistant cell cycle paths, could lead to improved cancer therapies targeting fractionally resistant cells to improve patient outcomes.
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Affiliation(s)
- Tarek M. Zikry
- Computational Medicine Program, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
- Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC27599
| | - Samuel C. Wolff
- Computational Medicine Program, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
| | - Jolene S. Ranek
- Computational Medicine Program, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
| | - Harris M. Davis
- Computational Medicine Program, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
| | - Ander Naugle
- Computational Medicine Program, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
| | - Namit Luthra
- Computational Medicine Program, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
| | - Austin A. Whitman
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
| | - Katarzyna M. Kedziora
- Center for Biologic Imaging, Department of Cell Biology, University of Pittsburg, Pittsburgh, PA15620
| | - Wayne Stallaert
- Department of Computational and Systems Biology, University of Pittsburg, Pittsburgh, PA15620
| | - Michael R. Kosorok
- Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC27599
| | - Philip M. Spanheimer
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
- Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
| | - Jeremy E. Purvis
- Computational Medicine Program, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
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Ranek JS, Stallaert W, Milner J, Stanley N, Purvis JE. Feature selection for preserving biological trajectories in single-cell data. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.09.540043. [PMID: 37214963 PMCID: PMC10197710 DOI: 10.1101/2023.05.09.540043] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Single-cell technologies can readily measure the expression of thousands of molecular features from individual cells undergoing dynamic biological processes, such as cellular differentiation, immune response, and disease progression. While examining cells along a computationally ordered pseudotime offers the potential to study how subtle changes in gene or protein expression impact cell fate decision-making, identifying characteristic features that drive continuous biological processes remains difficult to detect from unenriched and noisy single-cell data. Given that all profiled sources of feature variation contribute to the cell-to-cell distances that define an inferred cellular trajectory, including confounding sources of biological variation (e.g. cell cycle or metabolic state) or noisy and irrelevant features (e.g. measurements with low signal-to-noise ratio) can mask the underlying trajectory of study and hinder inference. Here, we present DELVE (dynamic selection of locally covarying features), an unsupervised feature selection method for identifying a representative subset of dynamically-expressed molecular features that recapitulates cellular trajectories. In contrast to previous work, DELVE uses a bottom-up approach to mitigate the effect of unwanted sources of variation confounding inference, and instead models cell states from dynamic feature modules that constitute core regulatory complexes. Using simulations, single-cell RNA sequencing data, and iterative immunofluorescence imaging data in the context of the cell cycle and cellular differentiation, we demonstrate that DELVE selects features that more accurately characterize cell populations and improve the recovery of cell type transitions. This feature selection framework provides an alternative approach for improving trajectory inference and uncovering co-variation amongst features along a biological trajectory. DELVE is implemented as an open-source python package and is publicly available at: https://github.com/jranek/delve.
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Affiliation(s)
- Jolene S. Ranek
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Computational Medicine Program, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Wayne Stallaert
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Justin Milner
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Natalie Stanley
- Computational Medicine Program, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jeremy E. Purvis
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Computational Medicine Program, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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