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PI3K p110α Blockade Enhances Anti-Tumor Efficacy of Abemaciclib in Human Colorectal Cancer Cells. Cancers (Basel) 2020; 12:cancers12092500. [PMID: 32899250 PMCID: PMC7564416 DOI: 10.3390/cancers12092500] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/17/2020] [Accepted: 09/01/2020] [Indexed: 12/24/2022] Open
Abstract
Simple Summary Colorectal cancer (CRC) is the third most common cancer and the second highest cause of cancer related mortality worldwide. Especially, the survival of advanced CRC patients who were failed to achieve durable remission after the anti-angiogenic and anti-epithelial growth factor receptor agents are still poor. The aim of our study was to investigate the anti-tumor activity of the CDK4/6 inhibitor, abemaciclib, as a single agent and to identify an optimal combination agent with abemaciclib in CRC cell lines. We confirmed that abemaciclib monotherapy showed anti-tumor activity and combination therapy with abemaciclib and BYL719 demonstrated synergistic effects in CRC cell lines. Moreover, our study suggested that PIK3CA mutation could be a predictive marker for efficacy of abemaciclib and BYL719 combination therapy. These findings provide novel insight into a possible therapeutic strategy for patients with relapsed and refractory CRC. Abstract Targeting cell cycle regulation in colorectal cancer has not been fully evaluated. We investigated the efficacy of the CDK4/6 inhibitor, abemaciclib, and confirmed a synergistic interaction for PI3K p110α and CDK dual inhibition in colorectal cancer cell lines. Caco-2 and SNU-C4 cell lines were selected to explore the mechanism of action for and resistance to abemaciclib. In vitro and in vivo models were used to validate the anti-tumor activity of abemaciclib monotherapy and BYL719 combination therapy. Abemaciclib monotherapy inhibited cell cycle progression and proliferation in Caco-2 and SNU-C4 cells. CDK2-mediated Rb phosphorylation and AKT phosphorylation appeared to be potential resistance mechanisms to abemaciclib monotherapy. Abemaciclib/BYL719 combination therapy demonstrated synergistic effects regardless of PIK3CA mutation status but showed greater efficacy in the PIK3CA mutated SNU-C4 cell line. Growth inhibition, cell cycle arrest, and migration inhibition were confirmed as mechanisms of action for this combination. In an SNU-C4 mouse xenograft model, abemaciclib/BYL719 combination resulted in tumor growth inhibition and apoptosis with tolerable toxicity. Dual blockade of PI3K p110α and CDK4/6 showed synergistic anti-tumor effects in vivo and in vitro in human colorectal cancer cell lines. This combination could be a promising candidate for the treatment of patients with advanced colorectal cancer.
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Lim E, Beith J, Boyle F, de Boer R, Hui R, McCarthy N, Redfern A, Wade T, Woodward N. Emerging data and future directions for CDK4/6 inhibitor treatment of patients with hormone receptor positive HER2-non-amplified metastatic breast cancer. Asia Pac J Clin Oncol 2018; 14 Suppl 4:12-21. [PMID: 30288929 DOI: 10.1111/ajco.13065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyclin-dependent kinase (CDK4/6) inhibitors in combination with endocrine therapy are currently the optimal first line treatment for hormone receptor (HR) positive, human epidermal growth factor receptor 2 (HER2) non-amplified metastatic breast cancer (MBC). However, not all patients benefit from this treatment and all patients will inevitably progress. Identifying therapeutic strategies in this setting is therefore of immediate clinical importance. We present an overview of the mechanisms of resistance to CDK4/6 inhibitors and review potential biomarkers that may guide therapy selection. We also discuss the use of CDK4/6 inhibitors in the context of non-HR-positive/HER2-non-amplified breast cancer and in combination with therapies other than endocrine therapy.
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Affiliation(s)
- Elgene Lim
- St.Vincent's Clinical School, University of New South Wales, Darlinghurst, NSW, 2010, Australia.,Garvan Institute of Medical Research, Darlinghurst, NSW, 2010, Australia
| | - Jane Beith
- University of Sydney, Camperdown, NSW, 2006, Australia.,Chris O'Brien Lifehouse, Camperdown, NSW, 2050, Australia
| | - Frances Boyle
- University of Sydney, Camperdown, NSW, 2006, Australia.,Mater Hospital, North Sydney, NSW, 2060, Australia
| | - Richard de Boer
- Peter MacCallum Cancer Centre, Melbourne, VIC 3000, Australia
| | - Rina Hui
- University of Sydney, Camperdown, NSW, 2006, Australia.,Westmead Hospital, Hawkesbury Road and Darcy Road, Westmead, NSW, 2145, Australia
| | - Nicole McCarthy
- ICON Cancer Care Wesley, Auchenflower, QLD, 4066.,University of Queensland, St Lucia, QLD, 4072, Australia
| | | | - Theresa Wade
- WriteSource Medical Pty Ltd, Lane Cove, NSW, 1595, Australia
| | - Natasha Woodward
- University of Queensland, St Lucia, QLD, 4072, Australia.,Mater Misericordiae Ltd and Mater Research Institute Raymond Terrace, South Brisbane, QLD, 4101, Australia
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