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Punessen NC, Pena C, Sandberg A, Koza LA, Linseman DA. A novel anti-apoptotic role for Cdc42/ACK-1 signaling in neurons. Mol Cell Neurosci 2023; 126:103865. [PMID: 37263460 DOI: 10.1016/j.mcn.2023.103865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 05/15/2023] [Accepted: 05/25/2023] [Indexed: 06/03/2023] Open
Abstract
Neurodegenerative diseases such as amyotrophic lateral sclerosis, Alzheimer's and Parkinson's disease are caused by a progressive and aberrant destruction of neurons in the brain and spinal cord. These disorders lack effective long-term treatments that impact the underlying mechanisms of pathogenesis and as a result, existing options focus primarily on alleviating symptomology. Dysregulated programmed cell death (i.e., apoptosis) is a significant contributor to neurodegeneration, and is controlled by a number of different factors. Rho family GTPases are molecular switches with recognized importance in proper neuronal development and migration that have more recently emerged as central regulators of apoptosis and neuronal survival. Here, we investigated a role for the Rho GTPase family member, Cdc42, and its downstream effectors, in neuronal survival and apoptosis. We initially induced apoptosis in primary cultures of rat cerebellar granule neurons (CGNs) by removing both growth factor-containing serum and depolarizing potassium from the cell medium. We then utilized both chemical inhibitors and adenoviral shRNA targeted to Cdc42 to block the function of Cdc42 or its downstream effectors under either control or apoptotic conditions. Our in vitro studies demonstrate that functional inhibition of Cdc42 or its downstream effector, activated Cdc42-associated tyrosine kinase-1 (ACK-1), had no adverse effects on CGN survival under control conditions, but significantly sensitized neurons to cell death under apoptotic conditions. In conclusion, our results suggest a key pro-survival role for Cdc42/ACK-1 signaling in neurons, particularly in regulating neuronal susceptibility to pro-apoptotic stress such as that observed in neurodegenerative disorders.
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Affiliation(s)
- Noelle C Punessen
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Claudia Pena
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Alexandra Sandberg
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Lilia A Koza
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Daniel A Linseman
- Department of Biological Sciences, University of Denver, Denver, CO, USA; Knoebel Institute for Healthy Aging, University of Denver, Denver, CO, USA.
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2
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The non-receptor tyrosine kinase ACK: regulatory mechanisms, signalling pathways and opportunities for attACKing cancer. Biochem Soc Trans 2020; 47:1715-1731. [PMID: 31845724 DOI: 10.1042/bst20190176] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/30/2019] [Accepted: 12/03/2019] [Indexed: 12/16/2022]
Abstract
Activated Cdc42-associated kinase or ACK, is a non-receptor tyrosine kinase and an effector protein for the small G protein Cdc42. A substantial body of evidence has accumulated in the past few years heavily implicating ACK as a driver of oncogenic processes. Concomitantly, more is also being revealed regarding the signalling pathways involving ACK and molecular details of its modes of action. Some details are also available regarding the regulatory mechanisms of this kinase, including activation and regulation of its catalytic activity, however, a full understanding of these aspects remains elusive. This review considers the current knowledge base concerning ACK and summarizes efforts and future prospects to target ACK therapeutically in cancer.
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Research Progress of the Functional Role of ACK1 in Breast Cancer. BIOMED RESEARCH INTERNATIONAL 2019; 2019:1018034. [PMID: 31772931 PMCID: PMC6854235 DOI: 10.1155/2019/1018034] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 09/13/2019] [Indexed: 01/25/2023]
Abstract
ACK1 is a nonreceptor tyrosine kinase with a unique structure, which is tightly related to the biological behavior of tumors. Previous studies have demonstrated that ACK1 was involved with multiple signaling pathways of tumor progression. Its crucial role in tumor cell proliferation, apoptosis, invasion, and metastasis was tightly related to the prognosis and clinicopathology of cancer. ACK1 has a unique way of regulating cellular pathways, different from other nonreceptor tyrosine kinases. As an oncogenic kinase, recent studies have shown that ACK1 plays a critical regulatory role in the initiation and progression of tumors. In this review, we will be summarizing the structural characteristics, activation, and regulation of ACK1 in breast cancer, aiming to deeply understand the functional and mechanistic role of ACK1 and provide novel therapeutic strategies for breast cancer treatment.
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4
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The Role of Apoptotic Signaling in Axon Guidance. J Dev Biol 2018; 6:jdb6040024. [PMID: 30340315 PMCID: PMC6316149 DOI: 10.3390/jdb6040024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 10/16/2018] [Accepted: 10/16/2018] [Indexed: 12/28/2022] Open
Abstract
Navigating growth cones are exposed to multiple signals simultaneously and have to integrate competing cues into a coherent navigational response. Integration of guidance cues is traditionally thought to occur at the level of cytoskeletal dynamics. Drosophila studies indicate that cells exhibit a low level of continuous caspase protease activation, and that axon guidance cues can activate or suppress caspase activity. We base a model for axon guidance on these observations. By analogy with other systems in which caspase signaling has non-apoptotic functions, we propose that caspase signaling can either reinforce repulsion or negate attraction in response to external guidance cues by cleaving cytoskeletal proteins. Over the course of an entire trajectory, incorrectly navigating axons may pass the threshold for apoptosis and be eliminated, whereas axons making correct decisions will survive. These observations would also explain why neurotrophic factors can act as axon guidance cues and why axon guidance systems such as Slit/Robo signaling may act as tumor suppressors in cancer.
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5
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Zeng QS, Xie BH, Xie YK, Wang XN. Activated Cdc42 kinase 1 and hepatocellular carcinoma. Shijie Huaren Xiaohua Zazhi 2016; 24:3853-3859. [DOI: 10.11569/wcjd.v24.i27.3853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Primary liver cancer includes hepatocellular carcinoma (HCC) and cholangiocellular carcinoma. The incidence of HCC is different between countries and regions. As one of the common malignant tumors in China, HCC has high mortality and is the second most common cause of cancer-related death. Elucidating the molecular mechanism of HCC pathogenesis is important for the diagnosis and treatment of liver cancer in China. The expression of activated Cdc42 kinase 1 (ACK1) has been found in a variety of cancers, and ACK1 participates in the occurrence and development of cancers. However, there are currently few studies about the relationship between ACK1 protein and HCC. This paper reviews the structure characteristics and biological function of ACK1 as well as its relationship with invasion and metastasis of HCC.
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Hu L, Xu J, Yin MX, Zhang L, Lu Y, Wu W, Xue Z, Ho MS, Gao G, Zhao Y, Zhang L. Ack promotes tissue growth via phosphorylation and suppression of the Hippo pathway component Expanded. Cell Discov 2016; 2:15047. [PMID: 27462444 PMCID: PMC4860957 DOI: 10.1038/celldisc.2015.47] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 12/01/2015] [Indexed: 12/11/2022] Open
Abstract
Non-receptor tyrosine kinase activated cdc42 kinase was reported to participate in several types of cancers in mammals. It is also believed to have an anti-apoptotic function in Drosophila. Here, we report the identification of Drosophila activated cdc42 kinase as a growth promoter and a novel Hippo signaling pathway regulator. We find that activated cdc42 kinase promotes tissue growth through modulating Yorkie activity. Furthermore, we demonstrate that activated cdc42 kinase interacts with Expanded and induces tyrosine phosphorylation of Expanded on multiple sites. We propose a model that activated cdc42 kinase negatively regulates Expanded by changing its phosphorylation status to promote tissue growth. Moreover, we show that ack genetically interacts with merlin and expanded. Thus, we identify Drosophila activated cdc42 kinase as a Hippo pathway regulator.
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Affiliation(s)
- Lianxin Hu
- State Key Laboratory of Cell Biology, Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China
| | - Jiajun Xu
- State Key Laboratory of Cell Biology, Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China
| | - Meng-Xin Yin
- State Key Laboratory of Cell Biology, Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China
| | - Liguo Zhang
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign , Urbana, IL, USA
| | - Yi Lu
- State Key Laboratory of Cell Biology, Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China
| | - Wenqing Wu
- State Key Laboratory of Cell Biology, Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China
| | - Zhaoyu Xue
- School of Life Sciences, Tsinghua University , Beijing, China
| | - Margaret S Ho
- Department of Anatomy and Neurobiology, School of Medicine, Tongji University , Shanghai, China
| | - Guanjun Gao
- School of Life Sciences, Tsinghua University , Beijing, China
| | - Yun Zhao
- State Key Laboratory of Cell Biology, Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Lei Zhang
- State Key Laboratory of Cell Biology, Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; School of Life Science and Technology, ShanghaiTech University, Shanghai, China
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7
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Di Cara F, Maile TM, Parsons BD, Magico A, Basu S, Tapon N, King-Jones K. The Hippo pathway promotes cell survival in response to chemical stress. Cell Death Differ 2015; 22:1526-39. [PMID: 26021298 PMCID: PMC4532776 DOI: 10.1038/cdd.2015.10] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Revised: 01/08/2015] [Accepted: 01/09/2015] [Indexed: 12/18/2022] Open
Abstract
Cellular stress defense mechanisms have evolved to maintain homeostasis in response to a broad variety of environmental challenges. Stress signaling pathways activate multiple cellular programs that range from the activation of survival pathways to the initiation of cell death when cells are damaged beyond repair. To identify novel players acting in stress response pathways, we conducted a cell culture RNA interference (RNAi) screen using caffeine as a xenobiotic stress-inducing agent, as this compound is a well-established inducer of detoxification response pathways. Specifically, we examined how caffeine affects cell survival when Drosophila kinases and phosphatases were depleted via RNAi. Using this approach, we identified and validated 10 kinases and 4 phosphatases that are essential for cell survival under caffeine-induced stress both in cell culture and living flies. Remarkably, our screen yielded an enrichment of Hippo pathway components, indicating that this pathway regulates cellular stress responses. Indeed, we show that the Hippo pathway acts as a potent repressor of stress-induced cell death. Further, we demonstrate that Hippo activation is necessary to inhibit a pro-apoptotic program triggered by the interaction of the transcriptional co-activator Yki with the transcription factor p53 in response to a range of stress stimuli. Our in vitro and in vivo loss-of-function data therefore implicate Hippo signaling in the transduction of cellular survival signals in response to chemical stress.
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Affiliation(s)
- F Di Cara
- Department of Cell Biology, Medical Sciences Building, Faculty of Medicine & Dentistry, University of Alberta, Edmonton T6G 2H7, Alberta, Canada
| | - T M Maile
- Genentech Inc., 1 DNA Way, South San Francisco, CA, USA
| | - B D Parsons
- Department of Medical Microbiology and Immunology, 6-020 Katz Group Centre, University of Alberta, Edmonton AB T6G 2E1, Alberta, Canada
| | - A Magico
- Department of Pediatrics, Faculty of Medicine & Dentistry, Katz Group Centre, University of Alberta, Edmonton T6G 2H7, Alberta, Canada
| | - S Basu
- Centre for Molecular Oncology, Institute of Cancer, Barts and The London School of Medicine and Dentistry, John Vane Science Centre, Charterhouse Square, London EC1M 6BQ, UK
| | - N Tapon
- Apoptosis and Proliferation Control Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - K King-Jones
- Department of Biological Sciences, University of Alberta, G-504 Biological Sciences Bldg, Edmonton T6G 2E9, Alberta, Canada
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8
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O’Keefe LV, Lee CS, Choo A, Richards RI. Tumor Suppressor WWOX Contributes to the Elimination of Tumorigenic Cells in Drosophila melanogaster. PLoS One 2015; 10:e0136356. [PMID: 26302329 PMCID: PMC4547717 DOI: 10.1371/journal.pone.0136356] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/31/2015] [Indexed: 01/27/2023] Open
Abstract
WWOX is a >1Mb gene spanning FRA16D Common Chromosomal Fragile Site, a region of DNA instability in cancer. Consequently, altered WWOX levels have been observed in a wide variety of cancers. In vitro studies have identified a large number and variety of potential roles for WWOX. Although its normal role in vivo and functional contribution to cancer have not been fully defined, WWOX does have an integral role in metabolism and can suppress tumor growth. Using Drosophila melanogaster as an in vivo model system, we find that WWOX is a modulator of TNFα/Egr-mediated cell death. We found that altered levels of WWOX can modify phenotypes generated by low level ectopic expression of TNFα/Egr and this corresponds to altered levels of Caspase 3 activity. These results demonstrate an in vivo role for WWOX in promoting cell death. This form of cell death is accompanied by an increase in levels of reactive oxygen species, the regulation of which we have previously shown can also be modified by altered WWOX activity. We now hypothesise that, through regulation of reactive oxygen species, WWOX constitutes a link between alterations in cellular metabolism observed in cancer cells and their ability to evade normal cell death pathways. We have further shown that WWOX activity is required for the efficient removal of tumorigenic cells from a developing epithelial tissue. Together these results provide a molecular basis for the tumor suppressor functions of WWOX and the better prognosis observed in cancer patients with higher levels of WWOX activity. Understanding the conserved cellular pathways to which WWOX contributes provides novel possibilities for the development of therapeutic approaches to restore WWOX function in cancer.
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Affiliation(s)
- Louise V. O’Keefe
- Department of Genetics and Evolution, Centre for Molecular Pathology, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Cheng Shoou Lee
- Department of Genetics and Evolution, Centre for Molecular Pathology, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Amanda Choo
- Department of Genetics and Evolution, Centre for Molecular Pathology, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
| | - Robert I. Richards
- Department of Genetics and Evolution, Centre for Molecular Pathology, School of Biological Sciences, The University of Adelaide, Adelaide, Australia
- * E-mail:
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9
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Drosophila Small Heat Shock Proteins: An Update on Their Features and Functions. HEAT SHOCK PROTEINS 2015. [DOI: 10.1007/978-3-319-16077-1_25] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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10
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Mahajan K, Mahajan NP. ACK1/TNK2 tyrosine kinase: molecular signaling and evolving role in cancers. Oncogene 2014; 34:4162-7. [PMID: 25347744 PMCID: PMC4411206 DOI: 10.1038/onc.2014.350] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 09/17/2014] [Accepted: 09/22/2014] [Indexed: 01/11/2023]
Abstract
Deregulated tyrosine kinase signaling alters cellular homeostasis to drive cancer progression. The emergence of a non-receptor tyrosine kinase, ACK1 as an oncogenic kinase, has uncovered novel mechanisms by which tyrosine kinase signaling promotes cancer progression. While early studies focused on ACK1 (also known as activated Cdc42-associated kinase 1 or TNK2) as a cytosolic effecter of activated transmembrane receptor tyrosine kinases (RTKs), wherein it shuttles between the cytosol and the nucleus to rapidly transduce extracellular signals from the RTKs to the intracellular effectors, recent data unfold a new aspect of its functionality as an epigenetic regulator. ACK1 interacts with the Estrogen Receptor (ER)/histone demethylase KDM3A (JHDM2a) complex, modifies KDM3A by tyrosine phosphorylation to regulate transcriptional outcome at HOXA1 locus to promote the growth of tamoxifen-resistant breast cancer. It is also well established that ACK1 regulates the activity of Androgen Receptor (AR) by tyrosine phosphorylation to fuel the growth of hormone-refractory prostate cancers. Further, recent explosion in genomic sequencing has revealed recurrent ACK1 gene amplification and somatic mutations in a variety of human malignancies, providing a molecular basis for its role in neoplastic transformation. In this review, we will discuss the various facets of ACK1 signaling, including its newly uncovered epigenetic regulator function, which enables cells to bypass the blockade to major survival pathways to promote resistance to standard cancer treatments. Not surprisingly, cancer cells appear to acquire an `addiction’ to ACK1 mediated survival, particularly under stress conditions, such as growth factor deprivation or genotoxic insults or hormone deprivation. With the accelerated development of potent and selective ACK1 inhibitors, targeted treatment for cancers harboring aberrant ACK1 activity may soon become a clinical reality.
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Affiliation(s)
- K Mahajan
- 1] Moffitt Cancer Center, Drug Discovery Department, Tampa, FL, USA [2] Department of Oncologic Sciences, University of South Florida, Tampa, FL, USA
| | - N P Mahajan
- 1] Moffitt Cancer Center, Drug Discovery Department, Tampa, FL, USA [2] Department of Oncologic Sciences, University of South Florida, Tampa, FL, USA
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11
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Src kinase function controls progenitor cell pools during regeneration and tumor onset in the Drosophila intestine. Oncogene 2014; 34:2371-84. [DOI: 10.1038/onc.2014.163] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 03/28/2014] [Accepted: 03/29/2014] [Indexed: 12/11/2022]
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12
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Mahajan K, Mahajan NP. ACK1 tyrosine kinase: targeted inhibition to block cancer cell proliferation. Cancer Lett 2013; 338:185-92. [PMID: 23597703 DOI: 10.1016/j.canlet.2013.04.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 04/03/2013] [Accepted: 04/08/2013] [Indexed: 01/05/2023]
Abstract
ACK1 tyrosine kinase, located on chromosome 3q29, is aberrantly activated, amplified or mutated in a wide variety of human cancers. While the deregulated kinase is oncogenic and its activation correlates with progression to metastatic stage, its inhibition causes cell cycle arrest, sensitizes cells to ionizing radiation and induces apoptosis. Oncogenicity of ACK1 is not only due to its ability to promote activation of critical pro-survival kinases and harmone receptors by phosphorylating at distinct tyrosine residues, but also by employing a similar mechanism to eliminate a tumor suppressor from cancer cells. Despite the substantial data supporting the oncogenic role of ACK1, and the potential clinical benefit of blocking ACK1 in metastatic disease, to date ACK1-specific small molecule inhibitors have not been exploited for cancer therapy. This review highlights recent advances that elucidate how cancer cells employ ACK1 kinase to their advantage and discusses some of the novel ACK1 inhibitors that have shown promise in pre-clinical studies.
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Affiliation(s)
- Kiran Mahajan
- Drug Discovery Department, Moffitt Cancer Center, 12902 Magnolia Drive, Tampa, FL 33612, USA.
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13
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Shen W, Chen X, Cormier O, Cheng DCP, Reed B, Harden N. Modulation of morphogenesis by Egfr during dorsal closure in Drosophila. PLoS One 2013; 8:e60180. [PMID: 23579691 PMCID: PMC3620322 DOI: 10.1371/journal.pone.0060180] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 02/23/2013] [Indexed: 01/12/2023] Open
Abstract
During Drosophila embryogenesis the process of dorsal closure (DC) results in continuity of the embryonic epidermis, and DC is well recognized as a model system for the analysis of epithelial morphogenesis as well as wound healing. During DC the flanking lateral epidermal sheets stretch, align, and fuse along the dorsal midline, thereby sealing a hole in the epidermis occupied by an extra-embryonic tissue known as the amnioserosa (AS). Successful DC requires the regulation of cell shape change via actomyosin contractility in both the epidermis and the AS, and this involves bidirectional communication between these two tissues. We previously demonstrated that transcriptional regulation of myosin from the zipper (zip) locus in both the epidermis and the AS involves the expression of Ack family tyrosine kinases in the AS in conjunction with Dpp secreted from the epidermis. A major function of Ack in other species, however, involves the negative regulation of Egfr. We have, therefore, asked what role Egfr might play in the regulation of DC. Our studies demonstrate that Egfr is required to negatively regulate epidermal expression of dpp during DC. Interestingly, we also find that Egfr signaling in the AS is required to repress zip expression in both the AS and the epidermis, and this may be generally restrictive to the progression of morphogenesis in these tissues. Consistent with this theme of restricting morphogenesis, it has previously been shown that programmed cell death of the AS is essential for proper DC, and we show that Egfr signaling also functions to inhibit or delay AS programmed cell death. Finally, we present evidence that Ack regulates zip expression by promoting the endocytosis of Egfr in the AS. We propose that the general role of Egfr signaling during DC is that of a braking mechanism on the overall progression of DC.
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Affiliation(s)
- Weiping Shen
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Xi Chen
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Olga Cormier
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - David Chung-Pei Cheng
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Bruce Reed
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Nicholas Harden
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
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14
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Abdallah AM, Zhou X, Kim C, Shah KK, Hogden C, Schoenherr JA, Clemens JC, Chang HC. Activated Cdc42 kinase regulates Dock localization in male germ cells during Drosophila spermatogenesis. Dev Biol 2013; 378:141-53. [PMID: 23562806 DOI: 10.1016/j.ydbio.2013.02.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Revised: 02/15/2013] [Accepted: 02/16/2013] [Indexed: 11/25/2022]
Abstract
Deregulation of the non-receptor tyrosine kinase ACK1 (Activated Cdc42-associated kinase) correlates with poor prognosis in cancers and has been implicated in promoting metastasis. To further understand its in vivo function, we have characterized the developmental defects of a null mutation in Drosophila Ack, which bears a high degree of sequence similarity to mammalian ACK1 but lacks a CRIB domain. We show that Ack, while not essential for viability, is critical for sperm formation. This function depends on Ack tyrosine kinase activity and is required cell autonomously in differentiating male germ cells at or after the spermatocyte stage. Ack associates predominantly with endocytic clathrin sites in spermatocytes, but disruption of Ack function has no apparent effect on clathrin localization and receptor-mediated internalization of Boss (Bride of sevenless) protein in eye discs. Instead, Ack is required for the subcellular distribution of Dock (dreadlocks), the Drosophila homolog of the SH2- and SH3-containing adaptor protein Nck. Moreover, Dock forms a complex with Ack, and the localization of Dock in male germ cells depends on its SH2 domain. Together, our results suggest that Ack-dependent tyrosine phosphorylation recruits Dock to promote sperm differentiation.
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Affiliation(s)
- Abbas M Abdallah
- Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, IN 47907-2054, USA
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