Title |
Small molecule inhibition of group I p21-activated kinases in breast cancer induces apoptosis and potentiates the activity of microtubule stabilizing agents
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Published in |
Breast Cancer Research, April 2015
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DOI | 10.1186/s13058-015-0564-5 |
Pubmed ID | |
Authors |
Christy C Ong, Sarah Gierke, Cameron Pitt, Meredith Sagolla, Christine K Cheng, Wei Zhou, Adrian M Jubb, Laura Strickland, Maike Schmidt, Sergio G Duron, David A Campbell, Wei Zheng, Seameen Dehdashti, Min Shen, Nora Yang, Mark L Behnke, Wenwei Huang, John C McKew, Jonathan Chernoff, William F Forrest, Peter M Haverty, Suet-Feung Chin, Emad A Rakha, Andrew R Green, Ian O Ellis, Carlos Caldas, Thomas O’Brien, Lori S Friedman, Hartmut Koeppen, Joachim Rudolph, Klaus P Hoeflich |
Abstract |
Breast cancer, the most common cause of cancer-related deaths worldwide among women, is a molecularly and clinically heterogeneous disease. Extensive genetic and epigenetic profiling of breast tumors has recently revealed novel putative driver genes, including p21-activated kinase 1 (PAK1). PAK1 is a serine/threonine kinase downstream of small GTP-binding proteins, Rac1 and Cdc42, and is an integral component of growth factor signaling networks and cellular functions fundamental to tumorigenesis. PAK1 dysregulation (copy number gain, mRNA and protein expression) was evaluated in two cohorts of breast cancer tissues (n = 980 and 1108). A novel small molecule inhibitor, FRAX1036, and RNA interference were used to examine PAK1 loss of function and combination with docetaxel in vitro. Mechanism of action for the therapeutic combination, both cellular and molecular, was assessed via time-lapse microscopy and immunoblotting. We demonstrate that focal genomic amplification and over-expression of PAK1 are associated with poor clinical outcome in the luminal subtype of breast cancer (P = 1.29 x 10(-4) and P = 0.015, respectively). Given the role for PAK1 in regulating cytoskeletal organization, we hypothesized that combination of PAK1 inhibition with taxane treatment could be combined to further interfere with microtubule dynamics and cell survival. Consistent with this, administration of docetaxel with either a novel small molecule inhibitor of group I PAKs, FRAX1036, or PAK1 small interfering RNA oligonucleotides dramatically altered signaling to cytoskeletal-associated proteins, such as stathmin, and induced microtubule disorganization and cellular apoptosis. Live-cell imaging revealed that the duration of mitotic arrest mediated by docetaxel was significantly reduced in the presence of FRAX1036, and this was associated with increased kinetics of apoptosis. Taken together, these findings further support PAK1 as a potential target in breast cancer and suggest combination with taxanes as a viable strategy to increase anti-tumor efficacy. |
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Geographical breakdown
Country | Count | As % |
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United States | 2 | 33% |
United Kingdom | 1 | 17% |
France | 1 | 17% |
Unknown | 2 | 33% |
Demographic breakdown
Type | Count | As % |
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Members of the public | 4 | 67% |
Science communicators (journalists, bloggers, editors) | 1 | 17% |
Practitioners (doctors, other healthcare professionals) | 1 | 17% |
Mendeley readers
Geographical breakdown
Country | Count | As % |
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United Kingdom | 1 | 1% |
India | 1 | 1% |
United States | 1 | 1% |
Sweden | 1 | 1% |
Unknown | 83 | 95% |
Demographic breakdown
Readers by professional status | Count | As % |
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Researcher | 17 | 20% |
Other | 16 | 18% |
Student > Ph. D. Student | 11 | 13% |
Student > Doctoral Student | 7 | 8% |
Student > Bachelor | 7 | 8% |
Other | 15 | 17% |
Unknown | 14 | 16% |
Readers by discipline | Count | As % |
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Agricultural and Biological Sciences | 29 | 33% |
Biochemistry, Genetics and Molecular Biology | 14 | 16% |
Medicine and Dentistry | 9 | 10% |
Chemistry | 8 | 9% |
Pharmacology, Toxicology and Pharmaceutical Science | 6 | 7% |
Other | 5 | 6% |
Unknown | 16 | 18% |