1. Combining CDK4/6 inhibition with taxanes enhances anti-tumor efficacy by sustained impairment of pRB-E2F pathways in squamous cell lung cancer
- Author
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James S. Hardwick, Ping Wei, Joan Cao, Hui Wang, Todd VanArsdale, Scott L. Weinrich, Paul A. Rejto, Shibing Deng, Goldie Y. L. Lui, Zhou Zhu, and Timothy Nichols
- Subjects
Bridged-Ring Compounds ,0301 basic medicine ,Cancer Research ,Lung Neoplasms ,Cell cycle checkpoint ,Pyridines ,medicine.medical_treatment ,Gene Expression ,Mice, Nude ,Angiogenesis Inhibitors ,Palbociclib ,Biology ,Retinoblastoma Protein ,Piperazines ,Cell Line ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Breast cancer ,Carcinoma, Non-Small-Cell Lung ,Cell Line, Tumor ,Antineoplastic Combined Chemotherapy Protocols ,Human Umbilical Vein Endothelial Cells ,Genetics ,medicine ,Animals ,Humans ,E2F ,Molecular Biology ,Cell Proliferation ,Mice, Inbred BALB C ,Taxane ,Neovascularization, Pathologic ,Retinoblastoma ,Cyclin-Dependent Kinase 4 ,Cancer ,Cyclin-Dependent Kinase 6 ,Immunotherapy ,medicine.disease ,E2F Transcription Factors ,G2 Phase Cell Cycle Checkpoints ,030104 developmental biology ,030220 oncology & carcinogenesis ,Carcinoma, Squamous Cell ,Cancer research ,Female ,Taxoids ,Signal Transduction - Abstract
The CDK4/6 inhibitor palbociclib reduces tumor growth by decreasing retinoblastoma (RB) protein phosphorylation and inducing cell cycle arrest at the G1/S phase transition. Palbociclib in combination with anti-hormonal therapy brings significant benefit to breast cancer patients. In this study, novel combination approaches and underlying molecular/cellular mechanisms for palbociclib were explored in squamous cell lung cancer (SqCLC), the second most common subtype of non-small cell lung cancer. While approximate 20% lung patients benefit from immunotherapy, most SqCLC patients who receive platinum-doublet chemotherapy as first-line treatment, which often includes a taxane, are still in need of more effective combination therapies. Our results demonstrated enhanced cytotoxicity and anti-tumor effect with palbociclib plus taxanes at clinically achievable doses in multiple SqCLC models with diverse cancer genetic backgrounds. Comprehensive gene expression analysis revealed a sustained disruption of pRB-E2F signaling by combination that was accompanied with enhanced regulation of pleiotropic biological effects. These included several novel mechanisms such as abrogation of G2/M and mitotic spindle assembly checkpoints, as well as impaired induction of hypoxia-inducible factor 1 alpha (HIF-1α). The decrease in HIF-1α modulated a couple key angiogenic and anti-angiogenic factors, resulting in an enhanced anti-angiogenic effect. This preclinical work suggests a new therapeutic opportunity for palbociclib in lung and other cancers currently treated with taxane based chemotherapy as standard of care.
- Published
- 2019