1. Single-cell dynamics determines response to CDK4/6 inhibition in triple negative breast cancer
- Author
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Asghar, US, Barr, AR, Cutts, R, Beaney, M, Babina, I, Sampath, D, Giltnane, J, Lacap, JA, Crocker, L, Young, A, Pearson, A, Herrera-Abreu, MT, Bakal, C, and Turner, NC
- Subjects
PROLIFERATION-QUIESCENCE DECISION ,Cell Survival ,Pyridines ,Mitosis ,Antineoplastic Agents ,Triple Negative Breast Neoplasms ,LETROZOLE ,Time-Lapse Imaging ,Article ,Piperazines ,SUBTYPES ,ACTIVATION ,Mice ,Phosphatidylinositol 3-Kinases ,CYCLIN-E ,Cell Line, Tumor ,Animals ,Humans ,1112 Oncology and Carcinogenesis ,Oncology & Carcinogenesis ,PHOSPHORYLATION ,Protein Kinase Inhibitors ,Cell Proliferation ,Science & Technology ,Cyclin-Dependent Kinase 4 ,ASSOCIATION ,Cyclin-Dependent Kinase 6 ,Molecular Imaging ,PALBOCICLIB ,Disease Models, Animal ,Phenotype ,Oncology ,Drug Resistance, Neoplasm ,Receptors, Androgen ,INACTIVATION ,Female ,biological phenomena, cell phenomena, and immunity ,Single-Cell Analysis ,Life Sciences & Biomedicine ,RESISTANCE ,Signal Transduction - Abstract
Purpose: Triple-negative breast cancer (TNBC) is a heterogeneous subgroup of breast cancer that is associated with a poor prognosis. We evaluated the activity of CDK4/6 inhibitors across the TNBC subtypes and investigated mechanisms of sensitivity. Experimental Design: A panel of cell lines representative of TNBC was tested for in vitro and in vivo sensitivity to CDK4/6 inhibition. A fluorescent CDK2 activity reporter was used for single-cell analysis in conjunction with time-lapse imaging. Results: The luminal androgen receptor (LAR) subtype of TNBC was highly sensitive to CDK4/6 inhibition both in vitro (P < 0.001 LAR vs. basal-like) and in vivo in MDA-MB-453 LAR cell line xenografts. Single-cell analysis of CDK2 activity demonstrated differences in cell-cycle dynamics between LAR and basal-like cells. Palbociclib-sensitive LAR cells exit mitosis with low levels of CDK2 activity, into a quiescent state that requires CDK4/6 activity for cell-cycle reentry. Palbociclib-resistant basal-like cells exit mitosis directly into a proliferative state, with high levels of CDK2 activity, bypassing the restriction point and the requirement for CDK4/6 activity. High CDK2 activity after mitosis is driven by temporal deregulation of cyclin E1 expression. CDK4/6 inhibitors were synergistic with PI3 kinase inhibitors in PIK3CA-mutant TNBC cell lines, extending CDK4/6 inhibitor sensitivity to additional TNBC subtypes. Conclusions: Cell-cycle dynamics determine the response to CDK4/6 inhibition in TNBC. CDK4/6 inhibitors, alone and in combination, are a novel therapeutic strategy for specific subgroups of TNBC. Clin Cancer Res; 23(18); 5561–72.
- Published
- 2017