1
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Li Y, Wang H, Zhang Z, Tang C, Zhou X, Mohan C, Wu T. Identification of polo-like kinase 1 as a therapeutic target in murine lupus. Clin Transl Immunology 2022; 11:e1362. [PMID: 35024139 PMCID: PMC8733964 DOI: 10.1002/cti2.1362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 09/21/2021] [Accepted: 11/29/2021] [Indexed: 11/18/2022] Open
Abstract
Introduction The signalling cascades that contribute to lupus pathogenesis are incompletely understood. We address this by using an unbiased activity‐based kinome screen of murine lupus. Methods An unbiased activity‐based kinome screen (ABKS) of 196 kinases was applied to two genetically different murine lupus strains. Systemic and renal lupus were evaluated following in vivo PLK1blockade. The upstream regulators and downstream targets of PLK1 were also interrogated. Results Multiple signalling cascades were noted to be more active in murine lupus spleens, including PLK1. In vivo administration of a PLK1‐specific inhibitor ameliorated splenomegaly, anti‐dsDNA antibody production, proteinuria, BUN and renal pathology in MRL.lpr mice (P < 0.05). Serum IL‐6, IL‐17 and kidney injury molecule 1 (KIM‐1) were significantly decreased after PLK1 inhibition. PLK1 inhibition reduced germinal centre and marginal zone B cells in the spleen, but changes in T cells were not significant. In vitro, splenocytes were treated with anti‐mouse CD40 Ab or F(ab’)2 fragment anti‐mouse IgM. After 24‐h stimulation, IL‐6 secretion was significantly reduced upon PLK1 blockade, whereas IL‐10 production was significantly increased. The phosphorylation of mTOR was assessed in splenocyte subsets, which revealed a significant change in myeloid cells. PLK1 blockade reduced phosphorylation associated with mTOR signalling, while Aurora‐A emerged as a potential upstream regulator of PLK1. Conclusion The Aurora‐A → PLK1 → mTOR signalling axis may be central in lupus pathogenesis, and emerges as a potential therapeutic target.
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Affiliation(s)
- Yaxi Li
- Department of Biomedical Engineering University of Houston Houston TX USA
| | - Hongting Wang
- Department of Biomedical Engineering University of Houston Houston TX USA
| | - Zijing Zhang
- Department of Biomedical Engineering University of Houston Houston TX USA.,Institute of Animal Husbandry and Veterinary Science Henan Academy of Agricultural Sciences Zhengzhou Henan China
| | - Chenling Tang
- Department of Biomedical Engineering University of Houston Houston TX USA
| | - Xinjin Zhou
- Department of Pathology Baylor University Medical Center at Dallas Dallas TX USA
| | - Chandra Mohan
- Department of Biomedical Engineering University of Houston Houston TX USA
| | - Tianfu Wu
- Department of Biomedical Engineering University of Houston Houston TX USA
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2
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Jung Y, Kraikivski P, Shafiekhani S, Terhune SS, Dash RK. Crosstalk between Plk1, p53, cell cycle, and G2/M DNA damage checkpoint regulation in cancer: computational modeling and analysis. NPJ Syst Biol Appl 2021; 7:46. [PMID: 34887439 PMCID: PMC8660825 DOI: 10.1038/s41540-021-00203-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 11/03/2021] [Indexed: 12/21/2022] Open
Abstract
Different cancer cell lines can have varying responses to the same perturbations or stressful conditions. Cancer cells that have DNA damage checkpoint-related mutations are often more sensitive to gene perturbations including altered Plk1 and p53 activities than cancer cells without these mutations. The perturbations often induce a cell cycle arrest in the former cancer, whereas they only delay the cell cycle progression in the latter cancer. To study crosstalk between Plk1, p53, and G2/M DNA damage checkpoint leading to differential cell cycle regulations, we developed a computational model by extending our recently developed model of mitotic cell cycle and including these key interactions. We have used the model to analyze the cancer cell cycle progression under various gene perturbations including Plk1-depletion conditions. We also analyzed mutations and perturbations in approximately 1800 different cell lines available in the Cancer Dependency Map and grouped lines by genes that are represented in our model. Our model successfully explained phenotypes of various cancer cell lines under different gene perturbations. Several sensitivity analysis approaches were used to identify the range of key parameter values that lead to the cell cycle arrest in cancer cells. Our resulting model can be used to predict the effect of potential treatments targeting key mitotic and DNA damage checkpoint regulators on cell cycle progression of different types of cancer cells.
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Affiliation(s)
- Yongwoon Jung
- grid.30760.320000 0001 2111 8460Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI 53226 USA
| | - Pavel Kraikivski
- Academy of Integrated Science, Division of Systems Biology, Virginia Tech, Blacksburg, VA, 24061, USA.
| | - Sajad Shafiekhani
- grid.411705.60000 0001 0166 0922Department of Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Scott S. Terhune
- grid.30760.320000 0001 2111 8460Departments of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI 53226 USA ,grid.30760.320000 0001 2111 8460Center of Systems and Molecular Medicine, Medical College of Wisconsin, Milwaukee, WI 53226 USA
| | - Ranjan K. Dash
- grid.30760.320000 0001 2111 8460Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI 53226 USA ,grid.30760.320000 0001 2111 8460Center of Systems and Molecular Medicine, Medical College of Wisconsin, Milwaukee, WI 53226 USA ,grid.30760.320000 0001 2111 8460Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226 USA
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3
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Raab CA, Raab M, Becker S, Strebhardt K. Non-mitotic functions of polo-like kinases in cancer cells. Biochim Biophys Acta Rev Cancer 2021; 1875:188467. [PMID: 33171265 DOI: 10.1016/j.bbcan.2020.188467] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/03/2020] [Accepted: 11/03/2020] [Indexed: 12/12/2022]
Abstract
Inhibitors of mitotic protein kinases are currently being developed as non-neurotoxic alternatives of microtubule-targeting agents (taxanes, vinca alkaloids) which provide a substantial survival benefit for patients afflicted with different types of solid tumors. Among the mitotic kinases, the cyclin-dependent kinases, the Aurora kinases, the kinesin spindle protein and Polo-like kinases (PLKs) have emerged as attractive targets of cancer therapeutics. The functions of mammalian PLK1-5 are traditionally linked to the regulation of the cell cycle and to the stress response. Especially the key role of PLK1 and PLK4 in cellular growth and proliferation, their overexpression in multiple types of human cancer and their druggability, make them appealing targets for cancer therapy. Inhibitors for PLK1 and PLK4 are currently being tested in multiple cancer trials. The clinical success of microtubule-targeting agents is attributed not solely to the induction of a mitotic arrest in cancer cells, but also to non-mitotic effects like targeting intracellular trafficking on microtubules. This raises the question whether new cancer targets like PLK1 and PLK4 regulate critical non-mitotic functions in tumor cells. In this article we summarize the important roles of PLK1-5 for the regulation of non-mitotic signaling. Due to these functions it is conceivable that inhibitors for PLK1 or PLK4 can target interphase cells, which underscores their attractive potential as cancer drug targets. Moreover, we also describe the contribution of the tumor-suppressors PLK2, PLK3 and PLK5 to cancer cell signaling outside of mitosis. These observations highlight the urgent need to develop highly specific ATP-competitive inhibitors for PLK4 and for PLK1 like the 3rd generation PLK-inhibitor Onvansertib to prevent the inhibition of tumor-suppressor PLKs in- and outside of mitosis. The remarkable feature of PLKs to encompass a unique druggable domain, the polo-box-domain (PBD) that can be found only in PLKs offers the opportunity for the development of inhibitors that target PLKs exclusively. Beyond the development of mono-specific ATP-competitive PLK inhibitors, the PBD as drug target will support the design of new drugs that eradicate cancer cells based on the mitotic and non-mitotic function of PLK1 and PLK4.
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Affiliation(s)
| | - Monika Raab
- Department of Gynecology, Goethe-University, Frankfurt, Germany
| | - Sven Becker
- Department of Gynecology, Goethe-University, Frankfurt, Germany
| | - Klaus Strebhardt
- Department of Gynecology, Goethe-University, Frankfurt, Germany; German Cancer Consortium (DKTK), German Cancer Research Center, Partner Site Frankfurt am Main, Frankfurt, Germany.
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4
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Abdelfatah S, Fleischer E, Klinger A, Wong VKW, Efferth T. Identification of inhibitors of the polo-box domain of polo-like kinase 1 from natural and semisynthetic compounds. Invest New Drugs 2020; 38:1-9. [PMID: 30877426 DOI: 10.1007/s10637-019-00752-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 02/25/2019] [Indexed: 12/30/2022]
Abstract
PLK1 has an important role in the regulation of cell cycle and represents an important target for cancer treatment. This enzyme belongs to the Polo-like kinases family, which is characterized by a regulatory domain named Polo-box domain (PBD). Rather than regular kinase inhibitors, this domain provides high selectivity to PLK1. Here, we report on four novel PLK1 PBD inhibitors identified by cytotoxicity screening and fluorescence polarization assay of a chemical library of natural and semisynthetic compounds. These compounds revealed two- to three-fold higher selectivity to the PDB of PLK1 than to those of the related family members, PLK2 and PLK3. These four substances inhibited tumor cell growth of sensitive CCRF-CEM and multidrug-resistant CEM/ADR5000 leukemia cells. The tested compounds increased the apoptotic cell fraction, which indicates apoptosis as a major mechanism of cell death. Cell cycle analysis showed compound (5) arrested the cell cycle of CCRF-CEM cells in the G2/M phase, while the other three molecules ((compound (3), compound (4), and compound (6)) exerted pronounced cytotoxicity with an increase of cells in the sub-G1 population. Molecular docking was performed for the understanding of ligand-protein interaction, the tested candidates showed strong binding affinity to PLK1 PBD. In conclusion, we identified four new chemical scaffolds that may serve as lead compounds for the development of selective PLK1 inhibitors in the future.
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Affiliation(s)
- Sara Abdelfatah
- Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, 55128, Mainz, Germany
| | | | | | - Vincent Kam Wai Wong
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau, China
| | - Thomas Efferth
- Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, 55128, Mainz, Germany.
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5
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Li X, Nai S, Ding Y, Geng Q, Zhu B, Yu K, Zhu WG, Dong MQ, Su XD, Xu X, Li J. Polo-like kinase 1 (PLK1)-dependent phosphorylation of methylenetetrahydrofolate reductase (MTHFR) regulates replication via histone methylation. Cell Cycle 2017; 16:1933-1942. [PMID: 28820331 PMCID: PMC5638376 DOI: 10.1080/15384101.2017.1363942] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 07/30/2017] [Indexed: 01/12/2023] Open
Abstract
Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme regulating the folate cycle and its genetic variations have been associated with various human diseases. Previously we identified that MTHFR is phosphorylated by cyclin-dependent kinase 1 (CDK1) at T34 and MTHFR underlies heterochromatin maintenance marked by H3K9me3 levels. Herein we demonstrate that pT34 creates a binding motif that docks MTHFR to the polo-binding domain (PBD) of polo-like kinase 1 (PLK1), a fundamental kinase that orchestrates many cell cycle events. We show that PLK1 phosphorylates MTHFR at T549 in vitro and in vivo. Further, we uncovered a role of MTHFR in replication. First, MTHFR depletion increased the fraction of cells in S phase. This defect could not be rescued by siRNA resistant plasmids harboring T549A, but could be restored by overproduction of Suv4-20H2, the H4K20 methyltransferase. Moreover, siMTHFR attenuated H4K20me3 levels, which could be rescued by Suv4-20H2 overproduction. More importantly, we also investigated MTHFR-E429A, the protein product of an MTHFR single nucleotide variant. MTHFR-E429A overexpression also increased S phase cells and decreased H4K20me3 levels, and it is linked to a poor glioma prognosis in the Chinese population. Collectively, we have unveiled a vital role of PLK1-dependent phosphorylation of MTHFR in replication via histone methylation, and implicate folate metabolism with glioma.
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Affiliation(s)
- Xueyan Li
- Beijing Key Laboratory of DNA Damage Response and College of Life Science, Capital Normal University, Beijing, China
| | - Shanshan Nai
- Beijing Key Laboratory of DNA Damage Response and College of Life Science, Capital Normal University, Beijing, China
| | - Yuehe Ding
- National Institute of Biological Sciences, Beijing, China
| | - Qizhi Geng
- Beijing Key Laboratory of DNA Damage Response and College of Life Science, Capital Normal University, Beijing, China
| | - Bingtao Zhu
- Beijing Key Laboratory of DNA Damage Response and College of Life Science, Capital Normal University, Beijing, China
| | - Kai Yu
- Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing, China
| | - Wei-Guo Zhu
- Guangdong Key Laboratory of Genome Stability & Disease Prevention, Shenzhen University School of Medicine, Shenzhen, Guangdong, China
| | - Meng-Qiu Dong
- National Institute of Biological Sciences, Beijing, China
| | - Xiao-Dong Su
- Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, Beijing, China
| | - Xingzhi Xu
- Beijing Key Laboratory of DNA Damage Response and College of Life Science, Capital Normal University, Beijing, China
- Guangdong Key Laboratory of Genome Stability & Disease Prevention, Shenzhen University School of Medicine, Shenzhen, Guangdong, China
| | - Jing Li
- Beijing Key Laboratory of DNA Damage Response and College of Life Science, Capital Normal University, Beijing, China
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6
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Shin SB, Woo SU, Chin YW, Jang YJ, Yim H. Sensitivity of TP53-Mutated Cancer Cells to the Phytoestrogen Genistein Is Associated With Direct Inhibition of Plk1 Activity. J Cell Physiol 2017; 232:2818-2828. [PMID: 27861885 DOI: 10.1002/jcp.25680] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 11/07/2016] [Indexed: 11/09/2022]
Abstract
Polo-like kinase 1 (Plk1), a conserved Ser/Thr mitotic kinase, has been identified as a promising target for anticancer drug development because its overexpression is correlated with malignancy. Here, we found that genistein, an isoflavone, inhibits Plk1 kinase activity directly. Previously the mitotic disturbance phenomenon induced by treatment with genistein was not fully explained by its inhibitory effect on EGFR. In kinase profiling assays, it showed selectivity relative to a panel of kinases, including EGFR. Treatment with genistein induced cell death in a concentration-dependent manner in cancer cells from diverse tissue origins, but not in non-transformed cells such as hTERT-RPE or MCF10A cells. We also observed that genistein tended to be more selective against cancer cells with mutations in the TP53 gene. TP53-depeleted LNCaP and NCI-H460 cells using shRNA targeting human TP53 were more sensitive to cell death by treatment of genistein. Furthermore, genistein induced mitotic arrest by inhibiting Plk1 activity and, consequently, led to mitotic catastrophe and apoptosis. These data suggest that genistein may be a promising anticancer drug candidate due to its inhibitory activity against Plk1 as well as EGFR and effectiveness toward cancer cells, especially those with p53-mutation. J. Cell. Physiol. 232: 2818-2828, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Sol-Bi Shin
- Department of Pharmacy, College of Pharmacy, Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Gyeonggi-do, Korea
| | - Sang-Uk Woo
- Department of Pharmacy, College of Pharmacy, Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Gyeonggi-do, Korea
| | - Young-Won Chin
- College of Pharmacy and Integrated Research Institute for Drug Development, Dongguk University-Seoul, Goyang, Gyeonggi-do, Korea
| | - Young-Joo Jang
- Department of Nanobiomedical Science and BK21 PLUS Global Research Center for Regenerative Medicine, Dankook University, Cheonan, Korea
| | - Hyungshin Yim
- Department of Pharmacy, College of Pharmacy, Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Gyeonggi-do, Korea
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7
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Borgal L, Rinschen MM, Dafinger C, Liebrecht VI, Abken H, Benzing T, Schermer B. Jade-1S phosphorylation induced by CK1α contributes to cell cycle progression. Cell Cycle 2016; 15:1034-45. [PMID: 26919559 PMCID: PMC4889251 DOI: 10.1080/15384101.2016.1152429] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 02/04/2016] [Indexed: 12/13/2022] Open
Abstract
The PHD zinc finger protein Jade-1S is a component of the HBO1 histone acetyltransferase complex and binds chromatin in a cell cycle-dependent manner. Jade-1S also acts as an E3 ubiquitin ligase for the canonical Wnt effector protein β-catenin and is influenced by CK1α-mediated phosphorylation. To further elucidate the functional impact of this phosphorylation, we used a stable, low-level expression system to express either wild-type or mutant Jade-1S lacking the N-terminal CK1α phosphorylation motif. Interactome analyses revealed that the Jade-1S mutant unable to be phosphorylated by CK1α has an increased binding affinity to proteins involved in chromatin remodelling, histone deacetylation, transcriptional repression, and ribosome biogenesis. Interestingly, cells expressing the mutant displayed an elongated cell shape and a delay in cell cycle progression. Finally, phosphoproteomic analyses allowed identification of a Jade-1S site phosphorylated in the presence of CK1α but closely resembling a PLK1 phosphorylation motif. Our data suggest that Jade-1S phosphorylation at an N-terminal CK1α motif creates a PLK1 phospho-binding domain. We propose CK1α phosphorylation of Jade 1S to serve as a molecular switch, turning off chromatin remodelling functions of Jade-1S and allowing timely cell cycle progression. As Jade-1S protein expression in the kidney is altered upon renal injury, this could contribute to understanding mechanisms underlying epithelial injury repair.
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Affiliation(s)
- Lori Borgal
- Department II of Internal Medicine; University of Cologne; Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC); University of Cologne; Cologne, Germany
| | - Markus M. Rinschen
- Department II of Internal Medicine; University of Cologne; Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC); University of Cologne; Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne; Cologne, Germany
| | - Claudia Dafinger
- Department II of Internal Medicine; University of Cologne; Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC); University of Cologne; Cologne, Germany
| | - Valérie I. Liebrecht
- Center for Molecular Medicine Cologne (CMMC); University of Cologne; Cologne, Germany
- Department I of Internal Medicine; University of Cologne; Cologne, Germany
| | - Hinrich Abken
- Center for Molecular Medicine Cologne (CMMC); University of Cologne; Cologne, Germany
- Department I of Internal Medicine; University of Cologne; Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine; University of Cologne; Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC); University of Cologne; Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne; Cologne, Germany
- Systems Biology of Ageing Cologne; University of Cologne; Cologne, Germany
| | - Bernhard Schermer
- Department II of Internal Medicine; University of Cologne; Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC); University of Cologne; Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne; Cologne, Germany
- Systems Biology of Ageing Cologne; University of Cologne; Cologne, Germany
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8
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Shin SB, Woo SU, Yim H. Differential Cellular Effects of Plk1 Inhibitors Targeting the ATP-binding Domain or Polo-box Domain. J Cell Physiol 2015; 230:3057-67. [PMID: 25975351 DOI: 10.1002/jcp.25042] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 05/08/2015] [Indexed: 01/15/2023]
Abstract
The expression of polo-like kinase 1 (Plk1) correlates with malignancy and is thus recognized as a target for cancer therapy. In addition to the development of ATP-competitive Plk1 inhibitors, the polo-box domain (PBD), a unique functional domain of PLKs, is being targeted to develop Plk1-specific inhibitors. However, the action mechanisms of these two classes of Plk1 inhibitors have not been thoroughly evaluated. Here, we evaluate the differences in cellular effects of ATP-binding domain inhibitors (BI 2536, GSK 461364) and PBD inhibitors (poloxin, thymoquinone) to determine their mechanisms of Plk1 inhibition. Our data show that BI 2536 and GSK461364 increased the population of cells in the G2/M phase compared with controls, while treatment with poloxin and thymoquinone increased cell population in the S phase as well as in G2/M, in a p53-independent manner. The population of cells staining positively for p-Histone H3 and MPM2, mitotic index, was increased by treatment with BI 2536 or GSK461364, but not by treatment with poloxin or thymoquinone. Furthermore, treatment with BI 2536 or GSK461364 resulted in activation of the BubR1 spindle checkpoint kinase, suggesting that treatment with ATP-binding domain inhibitors induces metaphase arrest. However, the administration of poloxin and thymoquinone resulted in an increase in p21(WAF1) and S arrest, indicating that PBD inhibitors also affected interphase before mitotic entry. Taken together, these data suggest that the PDB of Plk1 plays a role in S phase progression through interaction with other proteins, while its ATP-binding domain is important for regulating mitotic progression mediated by its catalytic activity involving consumption of ATP.
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Affiliation(s)
- Sol-Bi Shin
- Department of Pharmacy, College of Pharmacy, Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Gyeonggi-do, Korea
| | - Sang-Uk Woo
- Department of Pharmacy, College of Pharmacy, Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Gyeonggi-do, Korea
| | - Hyungshin Yim
- Department of Pharmacy, College of Pharmacy, Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Gyeonggi-do, Korea
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9
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Sun L, Lamont SJ, Cooksey AM, McCarthy F, Tudor CO, Vijay-Shanker K, DeRita RM, Rothschild M, Ashwell C, Persia ME, Schmidt CJ. Transcriptome response to heat stress in a chicken hepatocellular carcinoma cell line. Cell Stress Chaperones 2015; 20:939-50. [PMID: 26238561 PMCID: PMC4595433 DOI: 10.1007/s12192-015-0621-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Revised: 06/22/2015] [Accepted: 06/30/2015] [Indexed: 12/31/2022] Open
Abstract
Heat stress triggers an evolutionarily conserved set of responses in cells. The transcriptome responds to hyperthermia by altering expression of genes to adapt the cell or organism to survive the heat challenge. RNA-seq technology allows rapid identification of environmentally responsive genes on a large scale. In this study, we have used RNA-seq to identify heat stress responsive genes in the chicken male white leghorn hepatocellular (LMH) cell line. The transcripts of 812 genes were responsive to heat stress (p < 0.01) with 235 genes upregulated and 577 downregulated following 2.5 h of heat stress. Among the upregulated were genes whose products function as chaperones, along with genes affecting collagen synthesis and deposition, transcription factors, chromatin remodelers, and genes modulating the WNT and TGF-beta pathways. Predominant among the downregulated genes were ones that affect DNA replication and repair along with chromosomal segregation. Many of the genes identified in this study have not been previously implicated in the heat stress response. These data extend our understanding of the transcriptome response to heat stress with many of the identified biological processes and pathways likely to function in adapting cells and organisms to hyperthermic stress. Furthermore, this study should provide important insight to future efforts attempting to improve species abilities to withstand heat stress through genome-wide association studies and breeding.
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Affiliation(s)
- Liang Sun
- Department of Animal and Food Sciences, University of Delaware, Newark, DE, 19716, USA
| | - Susan J Lamont
- Department of Animal Science, Iowa State University, Ames, IA, 50011, USA
| | - Amanda M Cooksey
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, 85721, USA
| | - Fiona McCarthy
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, 85721, USA
| | - Catalina O Tudor
- Department of Computer and Information Sciences, University of Delaware, Newark, DE, 19716, USA
| | - K Vijay-Shanker
- Department of Computer and Information Sciences, University of Delaware, Newark, DE, 19716, USA
| | - Rachael M DeRita
- Department of Animal and Food Sciences, University of Delaware, Newark, DE, 19716, USA
| | - Max Rothschild
- Department of Animal Science, Iowa State University, Ames, IA, 50011, USA
| | - Chris Ashwell
- Department of Poultry Science, North Carolina State University, Raleigh, NC, 27695, USA
| | - Michael E Persia
- Department of Animal Science, Iowa State University, Ames, IA, 50011, USA
| | - Carl J Schmidt
- Department of Animal and Food Sciences, University of Delaware, Newark, DE, 19716, USA.
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Lv P, Wang Y, Ma J, Wang Z, Li JL, Hong CS, Zhuang Z, Zeng YX. Inhibition of protein phosphatase 2A with a small molecule LB100 radiosensitizes nasopharyngeal carcinoma xenografts by inducing mitotic catastrophe and blocking DNA damage repair. Oncotarget 2015; 5:7512-24. [PMID: 25245035 PMCID: PMC4202140 DOI: 10.18632/oncotarget.2258] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Nasopharyngeal carcinoma (NPC), while uncommon worldwide, is a major health problem in China. Although local radiation and surgery provide good control of NPC, better treatments that permit reductions in radiation dosing are needed. Inhibition of protein phosphatase 2A (PP2A), a ubiquitous multifunctional enzyme with critical roles in cell cycle regulation and DNA-damage response, reportedly sensitizes cancer cells to radiation and chemotherapy. We studied PP2A inhibition with LB100, a small molecule currently in a Phase I clinical trial, on radiosensitization of two human nasopharyngeal cell lines: CNE1, which is reportedly radioresistant, and CNE2. In both cell lines, LB100 exposure increased intracellular p-Plk1, TCTP, and Cdk1 and decreased p53, changes associated with cell cycle arrest, mitotic catastrophe and radio-inhibition of cell proliferation. Mice bearing subcutaneous xenografts of either cell line were administered 1.5 mg/kg LB100 daily for three days and a single dose of 20 Gy radiation (day 3), which produced marked and prolonged tumor mass regression (dose enhancement factors of 2.98 and 2.27 for CNE1 and CNE2 xenografts, respectively). Treatment with either LB100 or radiation alone only transiently inhibited xenograft growth. Our results support further exploration of PP2A inhibition as part of radiotherapy regimens for NPC and potentially other solid tumors.
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Affiliation(s)
- Peng Lv
- Cancer Institute and Hospital, Chinese Academy of Medical Sciences (CAMS) ,Beijing , People's Republic of China. Beijing Neurosurgical Institute, Capital Medical University, Beijing, People's Republic of China
| | - Yue Wang
- Institute for Medical Device Standardization Administration, National Institutes for Food and Drug Control, Beijing , People's Republic of China
| | - Jie Ma
- Cancer Institute and Hospital, Chinese Academy of Medical Sciences (CAMS) ,Beijing , People's Republic of China
| | - Zheng Wang
- Cancer Institute and Hospital, Chinese Academy of Medical Sciences (CAMS) ,Beijing , People's Republic of China
| | - Jing-Li Li
- Institute for Medical Device Standardization Administration, National Institutes for Food and Drug Control, Beijing , People's Republic of China
| | - Christopher S Hong
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD ,USA
| | - Zhengping Zhuang
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD ,USA
| | - Yi-Xin Zeng
- Cancer Institute and Hospital, Chinese Academy of Medical Sciences (CAMS) ,Beijing , People's Republic of China. Department of Experimental Research, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong , People's Republic of China. State Key Laboratory of Oncology in Southern China, Guangzhou, Guangdong , People's Republic of China
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11
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Shao T, Liu X. Identification of rictor as a novel substrate of Polo-like kinase 1. Cell Cycle 2015; 14:755-60. [PMID: 25714006 PMCID: PMC4615041 DOI: 10.1080/15384101.2014.998050] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 12/08/2014] [Accepted: 12/09/2014] [Indexed: 10/23/2022] Open
Abstract
Plk1 has been essentially described as a critical regulator of many mitotic events. However, increasing evidence supports the notion that its molecular functions are not restricted to the cell cycle. In particular, recent reports suggest the existence of a molecular and functional link between Plk1 and the mammalian target of rapamycin (mTOR) pathway, which controls cell growth and proliferation via the raptor-mTOR (TORC1) and rictor-mTOR (TORC2) protein complexes. Herein, we have identified rapamycin-insensitive companion of mTOR (Rictor), a core component of mTORC2, as a new Plk1 substrate and have shown that Plk1 phosphorylates Rictor at Ser1162 in vitro and in vivo. Surprisingly, cells expressing the unphosphorylatable mutant (S1162A) of Rictor did not show any effect on well characterized canonical PI3K-mTOR pathway. However, we found that cells expressing the unphosphorylatable form of Rictor have an elevated level of mSin1 isoform (mSin1.5). Considering that mSin1.5-containing mTORC2 was reported to associate with stress signaling, we propose that phosphorylation of Rictor at Ser1162 by Plk1 might be involved in a novel signaling pathway by regulating the mSin1.5-defined mTORC2.
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Key Words
- 4E-BP1, eIF4E-binding protein 1
- GST, glutathione S-transferase
- IB, immunoblotting.
- IP, immunoprecipitation
- PDK1, 3-phophoinositide-dependent protein kinase 1 (PDK1)
- Plk1
- Plk1, polo-like kinase 1
- Raptor, regulatory-associated protein of mTOR
- Rictor
- Rictor, rapamycin-insensitive companion of mTOR
- S6K, S6 Kinase
- WT, wild type
- aa, amino acids
- cell cycle
- mSin1
- mSin1, mammalian stress-activated map kinase-interacting protein 1 (mSin1)
- mTOR, mammalian target of rapamycin
- mTORC
- mTORC1, mTOR complex 1
- mTORC2, mTOR complex 2
- phosphorylation
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Affiliation(s)
- Tian Shao
- Department of Biochemistry; Purdue University; West Lafayette, IN USA
| | - Xiaoqi Liu
- Department of Biochemistry; Purdue University; West Lafayette, IN USA
- Purdue Center for Cancer Research; Purdue University; West Lafayette, IN USA
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12
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Driscoll DL, Chakravarty A, Bowman D, Shinde V, Lasky K, Shi J, Vos T, Stringer B, Amidon B, D'Amore N, Hyer ML. Plk1 inhibition causes post-mitotic DNA damage and senescence in a range of human tumor cell lines. PLoS One 2014; 9:e111060. [PMID: 25365521 PMCID: PMC4218841 DOI: 10.1371/journal.pone.0111060] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 09/21/2014] [Indexed: 01/17/2023] Open
Abstract
Plk1 is a checkpoint protein whose role spans all of mitosis and includes DNA repair, and is highly conserved in eukaryotes from yeast to man. Consistent with this wide array of functions for Plk1, the cellular consequences of Plk1 disruption are diverse, spanning delays in mitotic entry, mitotic spindle abnormalities, and transient mitotic arrest leading to mitotic slippage and failures in cytokinesis. In this work, we present the in vitro and in vivo consequences of Plk1 inhibition in cancer cells using potent, selective small-molecule Plk1 inhibitors and Plk1 genetic knock-down approaches. We demonstrate for the first time that cellular senescence is the predominant outcome of Plk1 inhibition in some cancer cell lines, whereas in other cancer cell lines the dominant outcome appears to be apoptosis, as has been reported in the literature. We also demonstrate strong induction of DNA double-strand breaks in all six lines examined (as assayed by γH2AX), which occurs either during mitotic arrest or mitotic-exit, and may be linked to the downstream induction of senescence. Taken together, our findings expand the view of Plk1 inhibition, demonstrating the occurrence of a non-apoptotic outcome in some settings. Our findings are also consistent with the possibility that mitotic arrest observed as a result of Plk1 inhibition is at least partially due to the presence of unrepaired double-strand breaks in mitosis. These novel findings may lead to alternative strategies for the development of novel therapeutic agents targeting Plk1, in the selection of biomarkers, patient populations, combination partners and dosing regimens.
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Affiliation(s)
- Denise L. Driscoll
- Takeda Pharmaceuticals International Co., Cambridge, Massachusetts, United States of America
| | - Arijit Chakravarty
- Takeda Pharmaceuticals International Co., Cambridge, Massachusetts, United States of America
| | - Doug Bowman
- Takeda Pharmaceuticals International Co., Cambridge, Massachusetts, United States of America
| | - Vaishali Shinde
- Takeda Pharmaceuticals International Co., Cambridge, Massachusetts, United States of America
| | - Kerri Lasky
- Takeda Pharmaceuticals International Co., Cambridge, Massachusetts, United States of America
| | - Judy Shi
- Takeda Pharmaceuticals International Co., Cambridge, Massachusetts, United States of America
| | - Tricia Vos
- Takeda Pharmaceuticals International Co., Cambridge, Massachusetts, United States of America
| | - Bradley Stringer
- Takeda Pharmaceuticals International Co., Cambridge, Massachusetts, United States of America
| | - Ben Amidon
- Takeda Pharmaceuticals International Co., Cambridge, Massachusetts, United States of America
| | - Natalie D'Amore
- Takeda Pharmaceuticals International Co., Cambridge, Massachusetts, United States of America
| | - Marc L. Hyer
- Takeda Pharmaceuticals International Co., Cambridge, Massachusetts, United States of America
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13
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Li Z, Li J, Bi P, Lu Y, Burcham G, Elzey BD, Ratliff T, Konieczny SF, Ahmad N, Kuang S, Liu X. Plk1 phosphorylation of PTEN causes a tumor-promoting metabolic state. Mol Cell Biol 2014; 34:3642-61. [PMID: 25047839 PMCID: PMC4187734 DOI: 10.1128/mcb.00814-14] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 07/17/2014] [Indexed: 11/20/2022] Open
Abstract
One outcome of activation of the phosphatidylinositol 3-kinase (PI3K) pathway is increased aerobic glycolysis, but the upstream signaling events that regulate the PI3K pathway, and thus the Warburg effect, are elusive. Increasing evidence suggests that Plk1, a cell cycle regulator, is also involved in cellular events in addition to mitosis. To test whether Plk1 contributes to activation of the PI3K pathway, and thus aerobic glycolysis, we examined potential targets of Plk1 and identified PTEN as a Plk1 substrate. We hypothesize that Plk1 phosphorylation of PTEN leads to its inactivation, activation of the PI3K pathway, and the Warburg effect. Our data show that overexpression of Plk1 leads to activation of the PI3K pathway and enhanced aerobic glycolysis. In contrast, inhibition of Plk1 causes markedly reduced glucose metabolism in mice. Mechanistically, we show that Plk1 phosphorylation of PTEN and Nedd4-1, an E3 ubiquitin ligase of PTEN, results in PTEN inactivation. Finally, we show that Plk1 phosphorylation of PTEN promotes tumorigenesis in both its phosphatase-dependent and -independent pathways, revealing potentially new drug targets to arrest tumor cell growth.
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Affiliation(s)
- Zhiguo Li
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Jie Li
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Pengpeng Bi
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Ying Lu
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA
| | - Grant Burcham
- Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana, USA
| | - Bennett D Elzey
- Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana, USA
| | - Timothy Ratliff
- Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana, USA Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana, USA
| | - Stephen F Konieczny
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana, USA
| | - Nihal Ahmad
- Department of Dermatology, University of Wisconsin, Madison, Wisconsin, USA
| | - Shihuan Kuang
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana, USA Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana, USA
| | - Xiaoqi Liu
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, USA Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana, USA
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14
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Giráldez S, Herrero-Ruiz J, Mora-Santos M, Japón MÁ, Tortolero M, Romero F. SCF(FBXW7α) modulates the intra-S-phase DNA-damage checkpoint by regulating Polo like kinase-1 stability. Oncotarget 2014; 5:4370-83. [PMID: 24970797 PMCID: PMC4147330 DOI: 10.18632/oncotarget.2021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 05/26/2014] [Indexed: 12/22/2022] Open
Abstract
The intra-S-checkpoint is essential to control cell progression through S phase under normal conditions and in response to replication stress. When DNA lesions are detected, replication fork progression is blocked allowing time for repair to avoid genomic instability and the risk of cancer. DNA replication initiates at many origins of replication in eukaryotic cells, where a series of proteins form pre-replicative complexes (pre-RCs) that are activated to become pre-initiation complexes and ensure a single round of replication in each cell cycle. PLK1 plays an important role in the regulation of DNA replication, contributing to the regulation of pre-RCs formation by phosphorylating several proteins, under both normal and stress conditions. Here we report that PLK1 is ubiquitinated and degraded by SCFFBXW7α/proteasome. Moreover, we identified a new Cdc4 phosphodegron in PLK1, conserved from yeast to humans, whose mutation prevents PLK1 destruction. We established that endogenous SCFFBXW7α degrades PLK1 in the G1 and S phases of an unperturbed cell cycle and in S phase following UV irradiation. Furthermore, we showed that FBXW7α overexpression or UV irradiation prevented the loading of proteins onto chromatin to form pre-RCs and, accordingly, reduced cell proliferation. We conclude that PLK1 degradation mediated by SCFFBXW7α modulates the intra-S-phase checkpoint.
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Affiliation(s)
- Servando Giráldez
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla. Apartado de correos 1095. 41080-Sevilla, Spain
| | - Joaquín Herrero-Ruiz
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla. Apartado de correos 1095. 41080-Sevilla, Spain
| | - Mar Mora-Santos
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla. Apartado de correos 1095. 41080-Sevilla, Spain
| | - Miguel Á. Japón
- Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla and Departamento de Anatomía Patológica, Hospital Universitario Virgen del Rocío, 41013 Sevilla, Spain
| | - Maria Tortolero
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla. Apartado de correos 1095. 41080-Sevilla, Spain
| | - Francisco Romero
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla. Apartado de correos 1095. 41080-Sevilla, Spain
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15
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Plk1-targeted therapies in TP53- or RAS-mutated cancer. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2014; 761:31-39. [PMID: 24630986 DOI: 10.1016/j.mrrev.2014.02.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/27/2014] [Accepted: 02/27/2014] [Indexed: 11/23/2022]
Abstract
Despite advances in treatment, prognosis for many types of carcinoma remains poor. Polo-like kinase 1 (Plk1) has been explored as a target for the development of anticancer drugs. As a mitotic master Ser/Thr kinase, Plk1 is involved in centrosomal maturation, microtubule nucleation, chromosomal segregation, and cytokinesis. Additional functions in interphase and in response to DNA damage have been revealed. The multiple locations of Plk1 correspond to distinct functions, mediated by phosphorylation of multiple substrates. Since it is highly expressed in several carcinomas, and expression of Plk1 is inversely correlated with the survival rate of patients in non-small cell lung, head and neck, and esophageal cancer, Plk1 is recognized as a valid prognostic marker. Connections between Plk1 and p53 or KRAS in carcinoma provide a rationale and several possible routes to the development of therapies. Tumors with both p53-deficiency and high Plk1 expression may be particularly sensitive to Plk1 inhibitors, although some controversial data exist. In KRAS-mutant cancers, on the other hand, Plk1 may be essential for tumor cell survival, but detailed studies as to whether Plk1 inhibitors are more effective in KRAS-mutant cancers must be performed in order to determine whether this is the case. Here, we present evidence for Plk1 as a prognostic marker and potentially effective target for the treatment of patients with carcinoma, to demonstrate the value of Plk1 as a target for the development of cancer treatment, especially for patients with solid tumors. In addition, the effects of Plk1 inhibition in p53- or KRAS-mutated cancer are discussed with respect to clinical implications. Structural specifics of Plk1 are presented, as well as current strategies for discovering new Plk1 inhibitors by targeting the conserved ATP binding site or polo-box domain of Plk1, in order to develop Plk1-specific anticancer drugs.
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16
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Abstract
Polo-like kinase 1 (Plk1) is a well-established mitotic regulator with a diverse range of biologic functions continually being identified throughout the cell cycle. Preclinical evidence suggests that the molecular targeting of Plk1 could be an effective therapeutic strategy in a wide range of cancers; however, that success has yet to be translated to the clinical level. The lack of clinical success has raised the question of whether there is a true oncogenic addiction to Plk1 or if its overexpression in tumors is solely an artifact of increased cellular proliferation. In this review, we address the role of Plk1 in carcinogenesis by discussing the cell cycle and DNA damage response with respect to their associations with classic oncogenic and tumor suppressor pathways that contribute to the transcriptional regulation of Plk1. A thorough examination of the available literature suggests that Plk1 activity can be dysregulated through key transformative pathways, including both p53 and pRb. On the basis of the available literature, it may be somewhat premature to draw a definitive conclusion on the role of Plk1 in carcinogenesis. However, evidence supports the notion that oncogene dependence on Plk1 is not a late occurrence in carcinogenesis and it is likely that Plk1 plays an active role in carcinogenic transformation.
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Affiliation(s)
- Brian D. Cholewa
- Department of Dermatology, University of Wisconsin, Madison, WI
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI
| | - Xiaoqi Liu
- Department of Biochemistry, Purdue University, West Lafayette, IN
| | - Nihal Ahmad
- Department of Dermatology, University of Wisconsin, Madison, WI
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI
- William S. Middleton Memorial VA Hospital, Madison, WI
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17
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Shen M, Cai Y, Yang Y, Yan X, Liu X, Zhou T. Centrosomal protein FOR20 is essential for S-phase progression by recruiting Plk1 to centrosomes. Cell Res 2013; 23:1284-95. [PMID: 24018379 PMCID: PMC3817547 DOI: 10.1038/cr.2013.127] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/13/2013] [Accepted: 07/16/2013] [Indexed: 12/28/2022] Open
Abstract
Centrosomes are required for efficient cell cycle progression mainly by orchestrating microtubule dynamics and facilitating G1/S and G2/M transitions. However, the role of centrosomes in S-phase progression is largely unknown. Here, we report that depletion of FOR20 (FOP-related protein of 20 kDa), a conserved centrosomal protein, inhibits S-phase progression and prevents targeting of Plk1 (polo-like kinase 1) to centrosomes, where FOR20 interacts with Plk1. Ablation of Plk1 also significantly induces S-phase defects, which are reversed by ectopic expression of Plk1, even a kinase-dead mutant, but not a mutant that fails to localize to centrosomes. Exogenous expression of centrosome-tethered Plk1, but not wild-type Plk1, overrides FOR20 depletion-induced S-phase defects independently of its kinase activity. Thus, these data indicate that recruitment of Plk1 to centrosomes by FOR20 may act as a signal to license efficient progression of S-phase. This represents a hitherto uncharacterized role of centrosomes in cell cycle regulation.
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Affiliation(s)
- Minhong Shen
- Department of Cell Biology and Program in Molecular Cell Biology, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, Zhejiang 310003, China
| | - Yuqi Cai
- Department of Cell Biology and Program in Molecular Cell Biology, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, Zhejiang 310003, China
| | - Yuehong Yang
- Department of Cell Biology and Program in Molecular Cell Biology, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, Zhejiang 310003, China
| | - Xiaoyi Yan
- Department of Cell Biology and Program in Molecular Cell Biology, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, Zhejiang 310003, China
| | - Xiaoqi Liu
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Tianhua Zhou
- Department of Cell Biology and Program in Molecular Cell Biology, Zhejiang University School of Medicine, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, Zhejiang 310003, China
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18
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Kim HJ, Cho JH, Kim JR. Downregulation of Polo-like kinase 1 induces cellular senescence in human primary cells through a p53-dependent pathway. J Gerontol A Biol Sci Med Sci 2013; 68:1145-56. [PMID: 23525475 DOI: 10.1093/gerona/glt017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Polo-like kinase 1 (PLK1) plays a key role in various stages of mitosis from entry into M phase to exit from mitosis. However, its role in cellular senescence remains to be determined. Therefore, the effects of PLK1 on cellular senescence in human primary cells were investigated. We found that expression of PLK1 decreased in human dermal fibroblasts and human umbilical vein endothelial cells under replicative senescence and premature senescence induced by adriamycin. PLK1 knockdown with PLK1 small interfering RNAs in young cells induced premature senescence. In contrast, upregulation of PLK1 in old cells partially reversed senescence phenotypes. Cellular senescence by PLK1 inhibition was observed in p16 knockdown cells but not in p53 knockdown cells. Our data suggest that PLK1 repression might result in cellular senescence in human primary cells via a p53-dependent pathway.
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Affiliation(s)
- Hee-Jin Kim
- These authors contributed equally to this work
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19
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Mok WC, Wasser S, Tan T, Lim SG. Polo-like kinase 1, a new therapeutic target in hepatocellular carcinoma. World J Gastroenterol 2012; 18:3527-36. [PMID: 22826617 PMCID: PMC3400854 DOI: 10.3748/wjg.v18.i27.3527] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 03/30/2012] [Accepted: 05/12/2012] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the role of polo-like kinase 1 (PLK1) as a therapeutic target for hepatocellular carcinoma (HCC). METHODS PLK1 gene expression was evaluated in HCC tissue and HCC cell lines. Gene knockdown with short-interfering RNA (siRNA) was used to study PLK1 gene and protein expression using real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blotting, and cell proliferation using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2(4-sulfophenyl)-2H-tetrazolium (MTS) and bromodeoxyuridine (BrdU) assays. Apoptosis was evaluated using the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and caspase-inhibition assay. Huh-7 cells were transplanted into nude mice and co-cultured with PLK1 siRNA or control siRNA, and tumor progression was compared with controls. RESULTS RT-PCR showed that PLK1 was overexpressed 12-fold in tumor samples compared with controls, and also was overexpressed in Huh-7 cells. siRNA against PLK1 showed a reduction in PLK1 gene and protein expression of up to 96% in Huh-7 cells, and a reduction in cell proliferation by 68% and 92% in MTS and BrdU cell proliferation assays, respectively. There was a 3-fold increase in apoptosis events, and TUNEL staining and caspase-3 assays suggested that this was caspase-independent. The pan-caspase inhibitor Z-VAD-FMK was unable to rescue the apoptotic cells. Immnofluorescence co-localized endonuclease-G to fragmented chromosomes, implicating it in apoptosis. Huh-7 cells transplanted subcutaneously into nude mice showed tumor regression in siPLK1-treated mice, but not in controls. CONCLUSION Knockdown of PLK1 overexpression in HCC was shown to be a potential therapeutic target, leading to apoptosis through the endonuclease-G pathway.
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20
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Li R, Chen DF, Zhou R, Jia SN, Yang JS, Clegg JS, Yang WJ. Involvement of polo-like kinase 1 (Plk1) in mitotic arrest by inhibition of mitogen-activated protein kinase-extracellular signal-regulated kinase-ribosomal S6 kinase 1 (MEK-ERK-RSK1) cascade. J Biol Chem 2012; 287:15923-34. [PMID: 22427657 PMCID: PMC3346105 DOI: 10.1074/jbc.m111.312413] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 01/28/2012] [Indexed: 11/06/2022] Open
Abstract
Cell division is controlled through cooperation of different kinases. Of these, polo-like kinase 1 (Plk1) and p90 ribosomal S6 kinase 1 (RSK1) play key roles. Plk1 acts as a G(2)/M trigger, and RSK1 promotes G(1) progression. Although previous reports show that Plk1 is suppressed by RSK1 during meiosis in Xenopus oocytes, it is still not clear whether this is the case during mitosis or whether Plk1 counteracts the effects of RSK1. Few animal models are available for the study of controlled and transient cell cycle arrest. Here we show that encysted embryos (cysts) of the primitive crustacean Artemia are ideal for such research because they undergo complete cell cycle arrest when they enter diapause (a state of obligate dormancy). We found that Plk1 suppressed the activity of RSK1 during embryonic mitosis and that Plk1 was inhibited during embryonic diapause and mitotic arrest. In addition, studies on HeLa cells using Plk1 siRNA interference and overexpression showed that phosphorylation of RSK1 increased upon interference and decreased after overexpression, suggesting that Plk1 inhibits RSK1. Taken together, these findings provide insights into the regulation of Plk1 during cell division and Artemia diapause cyst formation and the correlation between the activity of Plk1 and RSK1.
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Affiliation(s)
- Ran Li
- From the Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou 310058, China and
| | - Dian-Fu Chen
- From the Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou 310058, China and
| | - Rong Zhou
- From the Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou 310058, China and
| | - Sheng-Nan Jia
- From the Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou 310058, China and
| | - Jin-Shu Yang
- From the Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou 310058, China and
| | - James S. Clegg
- Section of Molecular and Cellular Biology and Bodega Marine Laboratory, University of California, Davis, Bodega Bay, California 94923
| | - Wei-Jun Yang
- From the Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou 310058, China and
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21
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Yoon HE, Kim SA, Choi HS, Ahn MY, Yoon JH, Ahn SG. Inhibition of Plk1 and Pin1 by 5'-nitro-indirubinoxime suppresses human lung cancer cells. Cancer Lett 2012; 316:97-104. [PMID: 22115795 DOI: 10.1016/j.canlet.2011.10.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 10/15/2011] [Accepted: 10/20/2011] [Indexed: 10/15/2022]
Abstract
A novel indirubin derivative, 5'-nitro-indirubinoxime (5'-NIO), exhibits a strong anti-cancer activity against human cancer cells. Here, the 5'-NIO-mediated G1 cell cycle arrest in lung cancer cells was associated with a decrease in protein levels of polo-like kinase 1 (Plk1) and peptidyl-prolyl cis/trans isomerase Pin1. Treatment with Plk1 siRNA or Pin1 inhibitor effectively inhibited the Rb phosphorylation, suggesting their regulatory role at G1 phase. In addition, the overexpression of Plk1 or Pin1 inhibited apoptotic signals following the cleavage of PARP in 5'-NIO-treated cells. These findings suggest that 5'-NIO have potential anti-cancer efficacy through the inhibition of Plk1 or/and Pin1 expression.
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Affiliation(s)
- Hyo-Eun Yoon
- Department of Pathology, Chosun University College of Dentistry, Gwangju 501-759, Republic of Korea
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22
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Song B, Liu XS, Liu X. Polo-like kinase 1 (Plk1): an Unexpected Player in DNA Replication. Cell Div 2012; 7:3. [PMID: 22309699 PMCID: PMC3359159 DOI: 10.1186/1747-1028-7-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 02/06/2012] [Indexed: 12/16/2022] Open
Abstract
Regulation of cell cycle progression is important for the maintenance of genome integrity, and Polo-like kinases (Plks) have been identified as key regulators of this process. It is well established that Polo-like kinase 1 (Plk1) plays critical roles in mitosis but little is known about its functions at other stages of the cell cycle. Here we summarize the functions of Plk1 during DNA replication, focusing on the molecular events related to Origin Recognition Complex (ORC), the complex that is essential for the initiation of DNA replication. Within the context of Plk1 phosphorylation of Orc2, we also emphasize regulation of Orc2 in different organisms. This review is intended to provide some insight into how Plk1 coordinates DNA replication in S phase with chromosome segregation in mitosis, and orchestrates the cell cycle as a whole.
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Affiliation(s)
- Bing Song
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA.
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23
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Song B, Liu XS, Davis K, Liu X. Plk1 phosphorylation of Orc2 promotes DNA replication under conditions of stress. Mol Cell Biol 2011; 31:4844-56. [PMID: 21947279 PMCID: PMC3232917 DOI: 10.1128/mcb.06110-11] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 09/14/2011] [Indexed: 12/27/2022] Open
Abstract
Polo-like kinase 1 (Plk1) plays pivotal roles in mitosis; however, little is known about its function in S phase. In this study, we show that inhibition of Plk1 impairs DNA replication and results in slow S-phase progression in cultured cancer cells. We have identified origin recognition complex 2 (Orc2), a member of the DNA replication machinery, as a Plk1 substrate and have shown that Plk1 phosphorylates Orc2 at Ser188 in vitro and in vivo. Furthermore, Orc2-S188 phosphorylation is enhanced when DNA replication is under challenge induced by ultraviolet, hydroxyurea, gemcitabine, or aphidicolin treatment. Cells expressing the unphosphorylatable mutant (S188A) of Orc2 had defects in DNA synthesis under stress, suggesting that this phosphorylation event is critical to maintain DNA replication under stress. To dissect the mechanism pertinent to this observation, we showed that Orc2-S188 phosphorylation associates with DNA replication origin and that cells expressing Orc2-S188A mutant fail to maintain the functional pre-replicative complex (pre-RC) under DNA replication stress. Furthermore, the intra-S-phase checkpoint is activated in Orc2-S188A-expressing cells to cause delay of S-phase progress. Our study suggests a novel role of Plk1 in facilitating DNA replication under conditions of stress to maintain genomic integrity.
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Affiliation(s)
- Bing Song
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana 47907
| | - X. Shawn Liu
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana 47907
| | - Korbin Davis
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
| | - Xiaoqi Liu
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
- Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana 47907
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Seo YJ, Kim BS, Chun SY, Park YK, Kang KS, Kwon TG. Apoptotic effects of genistein, biochanin-A and apigenin on LNCaP and PC-3 cells by p21 through transcriptional inhibition of polo-like kinase-1. J Korean Med Sci 2011; 26:1489-94. [PMID: 22065906 PMCID: PMC3207053 DOI: 10.3346/jkms.2011.26.11.1489] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 09/13/2011] [Indexed: 01/02/2023] Open
Abstract
Natural isoflavones and flavones are important dietary factors for prostate cancer prevention. We investigated the molecular mechanism of these compounds (genistein, biochanin-A and apigenin) in PC-3 (hormone-independent/p53 mutant type) and LNCaP (hormone-dependent/p53 wild type) prostate cancer cells. A cell growth rate and apoptotic activities were analyzed in different concentrations and exposure time to evaluate the antitumor activities of genistein, biochanin-A and apigenin. The real time PCR and Western blot analysis were performed to investigate whether the molecular mechanism of these compounds are involving the p21 and PLK-1 pathway. Apoptosis of prostate cancer cells was associated with p21 up-regulation and PLK-1 suppression. Exposure of genistein, biochanin-A and apigenin on LNCaP and PC-3 prostate cancer cells resulted in same pattern of cell cycle arrest and apoptosis. The inhibition effect for cell proliferation was slightly greater in LNCaP than PC-3 cells. In conclusion, flavonoids treatment induces up-regulation of p21 expression, and p21 inhibits transcription of PLK-1, which promotes apoptosis of cancer cells.
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Affiliation(s)
- Young Jin Seo
- Department of Urology, College of Medicine, Dongguk University, Gyeongju, Korea
| | - Bum Soo Kim
- Department of Urology, School of Medicine, Kyungpook National University, Daegu, Korea
| | - So Young Chun
- Joint Institute for Regenerative Medicine, Kyungpook National University Hospital, Daegu, Korea
| | - Yoon Kyu Park
- Department of Urology, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Ku Seong Kang
- Department of Pathology, School of Medicine, Kyungpook National University, Daegu, Korea
| | - Tae Gyun Kwon
- Department of Urology, School of Medicine, Kyungpook National University, Daegu, Korea
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Yuan J, Sanhaji M, Krämer A, Reindl W, Hofmann M, Kreis NN, Zimmer B, Berg T, Strebhardt K. Polo-box domain inhibitor poloxin activates the spindle assembly checkpoint and inhibits tumor growth in vivo. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:2091-9. [PMID: 21839059 PMCID: PMC3181368 DOI: 10.1016/j.ajpath.2011.06.031] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 05/25/2011] [Accepted: 06/03/2011] [Indexed: 12/25/2022]
Abstract
Polo-like kinase 1 (Plk1) is widely established as one of the most promising targets in oncology. Although the protein kinase domain of Plk1 is highly conserved, the polo-box domain (PBD) of Plk1 provides a much more compelling site to specifically inhibit the localization and target binding of Plk1. We recently identified, via fluorescence polarization assay, the natural product derivative, Poloxin, as the first small-molecule inhibitor specifically targeting the function of the Plk1 PBD. In this study, we characterized its mitotic phenotype and its function in vitro and in vivo. Poloxin induces centrosome fragmentation and abnormal spindle and chromosome misalignment, which activate the spindle assembly checkpoint and prolong mitosis. Notably, centrosomal fragmentation induced by Poloxin is partially attributable to dysfunctional Kizuna, a key substrate of Plk1 at centrosomes. Moreover, Poloxin strongly inhibits proliferation of a panel of cancer cells by inducing mitotic arrest, followed by a surge of apoptosis. More important, we report, for the first time to our knowledge, that the PBD inhibitor, Poloxin, significantly suppresses tumor growth of cancer cell lines in xenograft mouse models by lowering the proliferation rate and triggering apoptosis in treated tumor tissues. The data highlight that targeting the PBD by Poloxin is a powerful approach for selectively inhibiting Plk1 function in vitro and in vivo.
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Affiliation(s)
- Juping Yuan
- Department of Gynecology and Obstetrics, School of Medicine, J. W. Goethe-University, Frankfurt, Germany
| | - Mourad Sanhaji
- Department of Gynecology and Obstetrics, School of Medicine, J. W. Goethe-University, Frankfurt, Germany
| | - Andrea Krämer
- Department of Gynecology and Obstetrics, School of Medicine, J. W. Goethe-University, Frankfurt, Germany
| | - Wolfgang Reindl
- Department of Molecular Biology, Max Planck Institute of Biochemistry, and the Center for Integrated Protein Science Munich, Martinsried, Germany
| | - Matthias Hofmann
- Department of Dermatology and Venerology, School of Medicine, J.W. Goethe-University, Frankfurt, Germany
| | - Nina-Naomi Kreis
- Department of Gynecology and Obstetrics, School of Medicine, J. W. Goethe-University, Frankfurt, Germany
| | - Brigitte Zimmer
- Department of Gynecology and Obstetrics, School of Medicine, J. W. Goethe-University, Frankfurt, Germany
| | - Thorsten Berg
- Department of Molecular Biology, Max Planck Institute of Biochemistry, and the Center for Integrated Protein Science Munich, Martinsried, Germany
- Institute for Organic Chemistry, University of Leipzig, Leipzig, Germany
| | - Klaus Strebhardt
- Department of Gynecology and Obstetrics, School of Medicine, J. W. Goethe-University, Frankfurt, Germany
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26
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Lens SMA, Voest EE, Medema RH. Shared and separate functions of polo-like kinases and aurora kinases in cancer. Nat Rev Cancer 2010; 10:825-41. [PMID: 21102634 DOI: 10.1038/nrc2964] [Citation(s) in RCA: 481] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Large numbers of inhibitors for polo-like kinases and aurora kinases are currently being evaluated as anticancer drugs. Interest in these drugs is fuelled by the idea that these kinases have unique functions in mitosis. Within the polo-like kinase family, the emphasis for targeted therapies has been on polo-like kinase 1 (PLK1), and in the aurora kinase family drugs have been developed to specifically target aurora kinase A (AURKA; also known as STK6) and/or aurora kinase B (AURKB; also known as STK12). Information on the selectivity of these compounds in vivo is limited, but it is likely that off-target effects within the same kinase families will affect efficacy and toxicity profiles. In addition, it is becoming clear that interplay between polo-like kinases and aurora kinases is much more extensive than initially anticipated, and that both kinase families are important factors in the response to classical chemotherapeutics that damage the genome or the mitotic spindle. In this Review we discuss the implications of these novel insights on the clinical applicability of polo-like kinase and aurora kinase inhibitors.
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Affiliation(s)
- Susanne M A Lens
- Department of Medical Oncology and Cancer Genomics Centre, UMC Utrecht, Universiteitsweg 100, Stratenum 2. 118, Utrecht 3584 CG, The Netherlands.
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27
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Berretta R, Moscato P. Cancer biomarker discovery: the entropic hallmark. PLoS One 2010; 5:e12262. [PMID: 20805891 PMCID: PMC2923618 DOI: 10.1371/journal.pone.0012262] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2009] [Accepted: 06/26/2010] [Indexed: 12/29/2022] Open
Abstract
Background It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods. Methodology/Principal Findings Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer. Conclusions/Significance We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-througput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases.
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Affiliation(s)
- Regina Berretta
- Centre for Bioinformatics, Biomarker Discovery and Information-Based Medicine, The University of Newcastle, Callaghan, New South Wales, Australia
- Information Based Medicine Program, Hunter Medical Research Institute, John Hunter Hospital, New Lambton Heights, New South Wales, Australia
| | - Pablo Moscato
- Centre for Bioinformatics, Biomarker Discovery and Information-Based Medicine, The University of Newcastle, Callaghan, New South Wales, Australia
- Information Based Medicine Program, Hunter Medical Research Institute, John Hunter Hospital, New Lambton Heights, New South Wales, Australia
- Australian Research Council Centre of Excellence in Bioinformatics, Callaghan, New South Wales, Australia
- * E-mail:
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28
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Chen YC, Su WC, Huang JY, Chao TC, Jeng KS, Machida K, Lai MMC. Polo-like kinase 1 is involved in hepatitis C virus replication by hyperphosphorylating NS5A. J Virol 2010; 84:7983-93. [PMID: 20534861 PMCID: PMC2916529 DOI: 10.1128/jvi.00068-10] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Accepted: 05/28/2010] [Indexed: 01/08/2023] Open
Abstract
Hepatitis C virus (HCV) replication involves many viral and host factors. Here, we employed a lentivirus-based RNA interference (RNAi) screening approach to search for possible cellular factors. By using a kinase-phosphatase RNAi library and an HCV replicon reporter system, we identified a serine-threonine kinase, Polo-like kinase 1 (Plk1), as a potential host factor regulating HCV replication. Knockdown of Plk1 reduced both HCV RNA replication and nonstructural (NS) protein production in both HCV replicon cells and HCV-infected cells while it did not significantly affect host cellular growth or cell cycle. Overexpression of Plk1 in the knockdown cells rescued HCV replication. Interestingly, the ratio between the hyperphosphorylated form (p58) and the basal phosphorylated form (p56) of NS5A was lower in the Plk1 knockdown cells and Plk1 kinase inhibitor-treated cells than in the control groups. Further studies showed that Plk1 could be immunoprecipitated together with NS5A. Both proteins partially colocalized in the perinuclear region. Furthermore, Plk1 could phosphorylate NS5A to both the p58 and p56 forms in an in vitro assay system; the phosphorylation efficiency was comparable to that of the reported casein kinase. Taken together, this study shows that Plk1 is an NS5A phosphokinase and thereby indirectly regulates HCV RNA replication. Because of the differential effects of Plk1 on HCV replication and host cell growth, Plk1 could potentially serve as a target for anti-HCV therapy.
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Affiliation(s)
- Yung-Chia Chen
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei 112, Taiwan, Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan, Institute of Biotechnology, National Tsing Hua University, Hsinchu 300, Taiwan, Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, 2001 Zonal Avenue, Los Angeles, California 90033, National Cheng Kung University, Tainan 701, Taiwan
| | - Wen-Chi Su
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei 112, Taiwan, Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan, Institute of Biotechnology, National Tsing Hua University, Hsinchu 300, Taiwan, Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, 2001 Zonal Avenue, Los Angeles, California 90033, National Cheng Kung University, Tainan 701, Taiwan
| | - Jing-Ying Huang
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei 112, Taiwan, Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan, Institute of Biotechnology, National Tsing Hua University, Hsinchu 300, Taiwan, Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, 2001 Zonal Avenue, Los Angeles, California 90033, National Cheng Kung University, Tainan 701, Taiwan
| | - Ti-Chun Chao
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei 112, Taiwan, Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan, Institute of Biotechnology, National Tsing Hua University, Hsinchu 300, Taiwan, Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, 2001 Zonal Avenue, Los Angeles, California 90033, National Cheng Kung University, Tainan 701, Taiwan
| | - King-Song Jeng
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei 112, Taiwan, Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan, Institute of Biotechnology, National Tsing Hua University, Hsinchu 300, Taiwan, Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, 2001 Zonal Avenue, Los Angeles, California 90033, National Cheng Kung University, Tainan 701, Taiwan
| | - Keigo Machida
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei 112, Taiwan, Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan, Institute of Biotechnology, National Tsing Hua University, Hsinchu 300, Taiwan, Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, 2001 Zonal Avenue, Los Angeles, California 90033, National Cheng Kung University, Tainan 701, Taiwan
| | - Michael M. C. Lai
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei 112, Taiwan, Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan, Institute of Biotechnology, National Tsing Hua University, Hsinchu 300, Taiwan, Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, 2001 Zonal Avenue, Los Angeles, California 90033, National Cheng Kung University, Tainan 701, Taiwan
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29
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Lu J, Kovach JS, Johnson F, Chiang J, Hodes R, Lonser R, Zhuang Z. Inhibition of serine/threonine phosphatase PP2A enhances cancer chemotherapy by blocking DNA damage induced defense mechanisms. Proc Natl Acad Sci U S A 2009; 106:11697-702. [PMID: 19564615 PMCID: PMC2710674 DOI: 10.1073/pnas.0905930106] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Indexed: 12/29/2022] Open
Abstract
A variety of mechanisms maintain the integrity of the genome in the face of cell stress. Cancer cell response to chemotherapeutic and radiation-induced DNA damage is mediated by multiple defense mechanisms including polo-like kinase 1 (Plk-1), protein kinase B (Akt-1), and/or p53 pathways leading to either apoptosis or cell cycle arrest. Subsequently, a subpopulation of arrested viable cancer cells may remain and recur despite aggressive and repetitive therapy. Here, we show that modulation (activation of Akt-1 and Plk-1 and repression of p53) of these pathways simultaneously results in paradoxical enhancement of the effectiveness of cytotoxic chemotherapy. We demonstrate that a small molecule inhibitor, LB-1.2, of protein phosphatase 2A (PP2A) activates Plk-1 and Akt-1 and decreases p53 abundance in tumor cells. Combined with temozolomide (TMZ; a DNA-methylating chemotherapeutic drug), LB-1.2 causes complete regression of glioblastoma multiforme (GBM) xenografts without recurrence in 50% of animals (up to 28 weeks) and complete inhibition of growth of neuroblastoma (NB) xenografts. Treatment with either drug alone results in only short-term inhibition/regression with all xenografts resuming rapid growth. Combined with another widely used anticancer drug, Doxorubicin (DOX, a DNA intercalating agent), LB-1.2 also causes marked GBM xenograft regression, whereas DOX alone only slows growth. Inhibition of PP2A by LB-1.2 blocks cell-cycle arrest and increases progression of cell cycle in the presence of TMZ or DOX. Pharmacologic inhibition of PP2A may be a general method for enhancing the effectiveness of cancer treatments that damage DNA or disrupt components of cell replication.
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Affiliation(s)
- Jie Lu
- Surgical Neurology Branch, National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Building 10, Room 5D37, 9000 Rockvillle Pike, Bethesda, MD 20892
| | - John S. Kovach
- Lixte Biotechnology Holdings, Inc., 248 Route 25 A, East Setauket, NY 11733
| | - Francis Johnson
- Chem-Master International, Inc., P.O. Box 563, East Setauket, NY 11733; and
| | - Jeffrey Chiang
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, 9000 Rockvillle Pike, Bethesda, MD 20892
| | - Richard Hodes
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, 9000 Rockvillle Pike, Bethesda, MD 20892
| | - Russell Lonser
- Surgical Neurology Branch, National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Building 10, Room 5D37, 9000 Rockvillle Pike, Bethesda, MD 20892
| | - Zhengping Zhuang
- Surgical Neurology Branch, National Institute of Neurologic Disorders and Stroke, National Institutes of Health, Building 10, Room 5D37, 9000 Rockvillle Pike, Bethesda, MD 20892
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Terry SYA, Riches AC, Bryant PE. Suppression of topoisomerase IIalpha expression and function in human cells decreases chromosomal radiosensitivity. Mutat Res 2009; 663:40-5. [PMID: 19428368 DOI: 10.1016/j.mrfmmm.2009.01.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 01/14/2009] [Accepted: 01/22/2009] [Indexed: 11/24/2022]
Abstract
The mechanism behind chromatid break formation is as yet unclear, although it is known that DNA double-strand breaks (DSBs) are the initiating lesions. Chromatid breaks formed in cells in the G2-phase of the cell-cycle disappear ('rejoin') as a function of time between radiation exposure and cell fixation. However, the kinetics of disappearance of chromatid breaks does not correspond to those of DSB rejoining, leading us to seek alternative models. We have proposed that chromatid breaks could be formed indirectly from DSB and that the mechanism involves topoisomerase IIalpha. In support of this hypothesis we have recently shown that frequencies of radiation-induced chromatid breaks are lower in two variant human promyelocytic leukaemic cell lines with reduced topoisomerase IIalpha expression. Here we report that suppression of topoisomerase IIalpha in human hTERT-RPE1 cells, either by its abrogation using specific siRNA or by inhibition of its catalytic activity with the inhibitor ICRF-193, causes a reduction in frequency of chromatid breaks in radiation-exposed cells. The findings support our hypothesis for the involvement of topoisomerase IIalpha in the formation of radiation-induced chromatid breaks, and could help explain inter-individual variation in human chromosomal radiosensitivity; elevation of which has been linked with cancer susceptibility.
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Affiliation(s)
- Samantha Y A Terry
- Bute Medical School, University of St Andrews, St Andrews, Scotland, UK.
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31
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Terry SYA, Riches AC, Bryant PE. Suppression of topoisomerase IIalpha expression and function in human cells decreases chromosomal radiosensitivity. Mutat Res 2009. [PMID: 19428368 DOI: 10.1016/j.mrfmmm] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2022]
Abstract
The mechanism behind chromatid break formation is as yet unclear, although it is known that DNA double-strand breaks (DSBs) are the initiating lesions. Chromatid breaks formed in cells in the G2-phase of the cell-cycle disappear ('rejoin') as a function of time between radiation exposure and cell fixation. However, the kinetics of disappearance of chromatid breaks does not correspond to those of DSB rejoining, leading us to seek alternative models. We have proposed that chromatid breaks could be formed indirectly from DSB and that the mechanism involves topoisomerase IIalpha. In support of this hypothesis we have recently shown that frequencies of radiation-induced chromatid breaks are lower in two variant human promyelocytic leukaemic cell lines with reduced topoisomerase IIalpha expression. Here we report that suppression of topoisomerase IIalpha in human hTERT-RPE1 cells, either by its abrogation using specific siRNA or by inhibition of its catalytic activity with the inhibitor ICRF-193, causes a reduction in frequency of chromatid breaks in radiation-exposed cells. The findings support our hypothesis for the involvement of topoisomerase IIalpha in the formation of radiation-induced chromatid breaks, and could help explain inter-individual variation in human chromosomal radiosensitivity; elevation of which has been linked with cancer susceptibility.
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Affiliation(s)
- Samantha Y A Terry
- Bute Medical School, University of St Andrews, St Andrews, Scotland, UK.
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32
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Takaki T, Trenz K, Costanzo V, Petronczki M. Polo-like kinase 1 reaches beyond mitosis--cytokinesis, DNA damage response, and development. Curr Opin Cell Biol 2008; 20:650-60. [PMID: 19000759 DOI: 10.1016/j.ceb.2008.10.005] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 09/29/2008] [Accepted: 10/13/2008] [Indexed: 01/12/2023]
Abstract
Polo-like kinase 1 (Plk1) is a key regulator of cell division in eukaryotic cells. In this review we focus on recent leaps in our understanding of how Plk1 controls cytokinesis, the final stage of cell division. Furthermore, we will go beyond mitosis to highlight unexpected roles of Plk1 during interphase and during animal development. In vertebrate cells, Plk1 has emerged as a novel player in maintaining genomic stability during DNA replication and as an important modulator of the DNA damage checkpoint. Plk1 functions extend past the 'core' cell cycle. Plk1 acts as a link between developmental processes and the cell cycle machinery during asymmetric cell divisions in flies and worms. The term 'mitotic kinase' might not do justice to Plk1 in the light of these recent results.
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Affiliation(s)
- Tohru Takaki
- Cell Division and Aneuploidy Laboratory, Cancer Research UK London Research Institute, Clare Hall Laboratories, South Mimms, Hertfordshire EN6 3LD, United Kingdom
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33
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Emerging cancer therapeutic opportunities by inhibiting mitotic kinases. Curr Opin Pharmacol 2008; 8:375-83. [PMID: 18644252 DOI: 10.1016/j.coph.2008.06.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 06/19/2008] [Accepted: 06/20/2008] [Indexed: 11/22/2022]
Abstract
Among cellular kinases, several cell cycle protein kinases play critical roles in mitotic entry and chromosome segregation. Inhibition of these proteins frequently results in dramatic mitotic arrest and subsequent apoptosis. Most drug discovery efforts have been directed against members of the cyclin-dependent kinase (CDK), Aurora and Polo-like kinase families. Inhibition of these proteins with small molecules has emerged as a powerful research tool and their clinical use is currently being tested in phase I and phase II trials for cancer therapy. New unexplored kinases or new protein domains distinct to the kinase pocket are now being evaluated for the next generation of mitotic drugs. The therapeutic value of inhibiting these kinases will improve with the availability of new specific and potent inhibitors, but it will also rely on a better knowledge of the physiological requirement for these proteins in normal and tumor cell cycles.
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