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Ana Maria G Dumitru, Scott F Rusin, Amber E M Clark, Arminja N Kettenbach, Duane A Compton
The fidelity of chromosome segregation in mitosis is safeguarded by the precise regulation of kinetochore microtubule (k-MT) attachment stability. Previously, we demonstrated that Cyclin A/Cdk1 destabilizes k-MT attachments to promote faithful chromosome segregation. Here, we use quantitative phosphoproteomics to identify 156 Cyclin A/Cdk1 substrates in prometaphase. One Cyclin A/Cdk1 substrate is myosin phosphatase targeting subunit 1 (MYPT1), and we show that MYPT1 localization to kinetochores depends on Cyclin A/Cdk1 activity and that MYPT1 destabilizes k-MT attachments by negatively regulating Plk1 at kinetochores...
November 20, 2017: ELife
Y Liao, D Lin, P Cui, B Abbasi, C Chen, Z Zhang, Y Zhang, Y Dong, R Rui, S Ju
Polo-like kinase 1 (Plk1), a type of serine/threonine protein kinase, has been implicated in various functions in the regulation of mitotic processes. However, these kinase's roles in meiotic division are not fully understood, particularly in the meiotic maturation of porcine oocytes. In this study, the expression and spatiotemporal localization of Plk1 were initially assessed in the meiotic process of pig oocytes by utilizing Western blotting with immunofluorescent staining combined with confocal microscopy imaging technique...
November 16, 2017: Reproduction in Domestic Animals, Zuchthygiene
T J Mitchison, J Pineda, J Shi, S Florian
Paclitaxel is a successful anti-cancer drug that kills cancer cells in two-dimensional culture through perturbation of mitosis, but whether it causes tumour regression by anti-mitotic actions is controversial. Drug candidates that specifically target mitosis, including inhibitors of kinesin-5, AurkA, AurkB and Plk1, disappointed in the clinic. Current explanations for this discrepancy include pharmacokinetic differences and hypothetical interphase actions of paclitaxel. Here, we discuss post-mitotic micronucleation as a special activity of taxanes that might explain their higher activity in solid tumours...
November 2017: Open Biology
Kazim Sahin, Mehmet Tuzcu, Mehmet Yabas, Cemal Orhan, Nurhan Sahin, Ibrahim H Ozercan
The goals of the present study were to define the anticancer activity of LFM-A13 (α-cyano-β-hydroxy-β-methyl-N-(2,5-dibromophenyl)-propenamide), a potent inhibitor of Polo-like kinase (PLK), in a mouse mammary cancer model induced by 7,12-dimethylbenz(a)anthracene (DMBA) in vivo and explore its anticancer mechanism(s). We also examined whether the inhibition of PLK by LFM-A13 would improve the efficiency of paclitaxel in breast cancer growth in vivo. To do this, female BALB/c mice received 1 mg of DMBA once a week for 6 weeks with oral gavage...
November 15, 2017: Investigational New Drugs
Zhiqing Li, Qixin Cui, Jian Xu, Daojun Cheng, Xiaoyan Wang, Bingqian Li, Jae Man Lee, Qingyou Xia, Takahiro Kusakabe, Ping Zhao
Polo-like kinase 1 (Plk1) is a crucial cell cycle regulator by its specific localization and activity during cell cycle. It has been shown that the phosphorylation and ubiquitylation of Plk1 are required for its own activation and localization. Here, we report that SUMOylation regulates the activity of Plk1 in the lepidopteran insect of Bombyx mori. In the absence of SUMOylation, it causes the lost localization of Plk1 on centrosomes and kinetochores, as well as an uneven distribution in midzone. We further identify that the putative SUMOylation site of Bombyx Plk1 at lysine 466 is required for its localization on centrosomes, and K466 mutation in Plk1 could influence its interaction with Smt3/Ubc9 complex...
November 14, 2017: Scientific Reports
Xiaoyu Ma, Lin Wang, De Huang, Yunyan Li, Dongdong Yang, Tingting Li, Fudong Li, Linchong Sun, Haoran Wei, Kun He, Fazhi Yu, Debiao Zhao, Lan Hu, Songge Xing, Zhaoji Liu, Kui Li, Jing Guo, Zhenye Yang, Xin Pan, Ailing Li, Yunyu Shi, Junfeng Wang, Ping Gao, Huafeng Zhang
Two hallmarks for cancer cells are the accelerated cell cycle progression as well as the altered metabolism, however, how these changes are coordinated to optimize the growth advantage for cancer cells are still poorly understood. Here we identify that Polo-like kinase 1 (Plk1), a key regulator for cell mitosis, plays a critical role for biosynthesis in cancer cells through activating pentose phosphate pathway (PPP). We find that Plk1 interacts with and directly phosphorylates glucose-6-phosphate dehydrogenase (G6PD)...
November 15, 2017: Nature Communications
Jose Thaiparambil, Oula Mansour, Randa El-Zein
Benzo[a]pyrene (B[a]P) is an environmental carcinogen found in tobacco smoke. It leads to high levels of DNA adducts in the lungs of cigarette smokers contributing to genomic instability. Alterations in the mitotic spindle apparatus play a major role in the generation of genomic instability through promoting chromosome mis-segregation and aneuploidy. To date, the effect of B[a]P exposure on altering the mitotic apparatus in normal lung epithelial cells remains unknown. In our study, BEAS-2B human bronchial epithelial cells were exposed to B[a]P and spindle dynamics were evaluated...
November 6, 2017: Toxicological Sciences: An Official Journal of the Society of Toxicology
Guodong Lian, Leping Li, Fei Ye, Daguang Wang, Jinglei Liu, Yulong Shi, Changqing Jing, Jian Suo, David Y Zhang, Man Chen
The present study was aimed to identify proteins associated with signaling pathways involved in chemoresistance, and establish a predictive model for chemoresistance in gastric cancer patients after radical surgery. A total of 140 clinically-staged III gastric cancer samples from patients after D2 radical gastrectomy were enrolled in the present study. Protein Pathway Array (PPA) and 286 antibodies were used to assess the protein expression in tumor tissues of patients. The Significance Analysis of Microarray (SAM) software and clustering and discriminant analysis were used to identify differentially expressed proteins between chemosensitive and chemoresistant subsets, and a predictive model for chemoresistance was established using the independent predictive factors...
November 6, 2017: Oncology Reports
Yoshiya Adachi, Yuichi Ishikawa, Hitoshi Kiyoi
Volasertib, a selective PLK1 inhibitor, was effective for acute myeloid leukemia (AML) patients in clinical trials. However, its efficacy was limited in mono-therapy, and a higher incidence of fatal events was revealed in the combination with low-dose cytarabine. Thus, optimization of combination therapy with volasertib and other agents is necessary for its clinical development, and the predictive factors for response or resistance to volasertib remain largely unknown. In this study, we investigated the resistance mechanism in volasertib-resistant cell lines and the combination effects with other agents, such as azacitidine (AZA), on AML cells...
October 3, 2017: Oncotarget
Yixi Xu, Shaokai Ning, Zheng Wei, Ran Xu, Xinlin Xu, Mengtan Xing, Rong Guo, Dongyi Xu
The cellular pathways that restart stalled replication forks are essential for genome stability and tumor prevention. However, how many of these pathways exist in cells and how these pathways are selectively activated remain unclear. Here, we describe two major fork restart pathways, and demonstrate that their selection is governed by 53BP1 and BRCA1, which are known to control the pathway choice to repair double-strand DNA breaks (DSBs). Specifically, 53BP1 promotes a fork cleavage-free pathway, whereas BRCA1 facilitates a break-induced replication (BIR) pathway coupled with SLX-MUS complex-mediated fork cleavage...
November 6, 2017: ELife
Juan Sun, Han-Yu Liu, Ruo-Fei Xu, Hai-Liang Zhu
Recent progress in the development of small molecular skeleton-derived polo-like kinase (PLK1) catalytic domain (KD) inhibitors has led to the synthesis of multiple ligands with high binding affinity. However, few systematic analyses have been conducted to identify key PLK1-PBD domain and characterize their interactions with potent PLK1 inhibitors. Therefore, we designed a series of PLK1-PBD inhibitors with an in silico scaffold modification strategy. A docking simulation combined with a primary screen in vitro were performed to filter for the lead compound, which was then substituted, synthesized and evaluated by a variety of bioassays...
October 28, 2017: Bioorganic & Medicinal Chemistry
Lara E Davis, Sophia Jeng, Matthew N Svalina, Elaine Huang, Janét Pittsenbarger, Emma L Cantor, Noah Berlow, Bernard Seguin, Atiya Mansoor, Shannon K McWeeney, Charles Keller
In complex, highly unstable genomes such as in osteosarcoma, targeting aberrant checkpoint processes (metabolic, cell cycle or immune) may prove more successful than targeting specific kinase or growth factor signaling pathways. Here, we establish a comparative oncology approach characterizing the most lethal osteosarcomas identified in a biorepository of tumors from three different species: human, mouse and canine. We describe the development of a genetically-engineered mouse model of osteosarcoma, establishment of primary cell cultures from fatal human tumors, and a biorepository of osteosarcoma surgical specimens from pet dogs...
September 29, 2017: Oncotarget
Yoshiyuki Hattori, Takuto Kikuchi, Kei-Ichi Ozaki, Hiraku Onishi
Mitotic progression is regulated by the phosphorylation of heat shock transcription factor 1 (HSF1) by polo-like kinase 1 (PLK1); however, this interaction is often deregulated in tumors. High expression levels of PLK1 and HSF1 have been observed in various types of human cancer. In the present study, it was investigated whether small interfering (si)RNA against PLK1 or HSF1 could suppress tumor growth in vitro and in vivo. In vitro transfection of PLK1 and HSF1 siRNA into PKL1- and HSF1-positive human breast tumor MDA-MB-231 and human cervical carcinoma HeLa cells inhibited cell growth via suppression of PLK1 and HSF1 mRNA expression, respectively...
November 2017: Experimental and Therapeutic Medicine
Monika I Linder, Mario Köhler, Paul Boersema, Marion Weberruss, Cornelia Wandke, Joseph Marino, Caroline Ashiono, Paola Picotti, Wolfram Antonin, Ulrike Kutay
During interphase, the nuclear envelope (NE) serves as a selective barrier between cytosol and nucleoplasm. When vertebrate cells enter mitosis, the NE is dismantled in the process of nuclear envelope breakdown (NEBD). Disassembly of nuclear pore complexes (NPCs) is a key aspect of NEBD, required for NE permeabilization and formation of a cytoplasmic mitotic spindle. Here, we show that both CDK1 and polo-like kinase 1 (PLK1) support mitotic NPC disintegration by hyperphosphorylation of Nup98, the gatekeeper nucleoporin, and Nup53, a central nucleoporin linking the inner NPC scaffold to the pore membrane...
October 23, 2017: Developmental Cell
T Renee Dawson, Susan R Wente
Reporting in this issue of Developmental Cell, Linder et al. (2017) and Martino et al. (2017) reveal in highly complementary studies that Plk1 is recruited to the nuclear pore complex upon mitotic entry, where it acts with Cdk1 to hyperphosphorylate nucleoporin interfaces to promote NPC disassembly and nuclear envelope breakdown.
October 23, 2017: Developmental Cell
C Shao, S-J Chien, E Farah, Z Li, N Ahmad, X Liu
Although Numb is well-recognized as a cell-fate determinant in stem/progenitor cells, accumulating evidence supports that Numb also has a critical role in adult tissues and cancers, in particular, in the context of regulation of tumor suppressor p53. Herein, we identified Numb as a novel substrate of Polo-like kinase 1 (Plk1). Of significance, we showed that Plk1-mediated phosphorylation of Numb leads to its enhanced proteasomal degradation and impaired Numb/p53 pathway, thus providing another mechanism how Plk1 antagonizes p53 during DNA damage response...
October 23, 2017: Oncogene
Chetan Nehate, Aji Alex Moothedathu Raynold, Veena Koul
To overcome the limitations of conventional chemotherapy, nanoparticle-mediated combinatorial delivery of siRNA and drugs represents a new approach to overcome its associated side effects. Designing safe and efficient vehicles for their codelivery has emerged as a potential challenge in the clinical translation of these formulations. Herein, we have demonstrated a novel "two-in-one" polyplex nanosystem developed from redox sensitive, short chain polyethylenimine modified poly[(poly(ethylene)glycol methacrylate]-s-s-polycaprolactone copolymer synthesized by atom-transfer free-radical polymerization (ATRP), which can deliver doxorubicin and polo-like kinase I (plk1) siRNA, simultaneously for an enhanced chemotherapeutic effect...
October 31, 2017: ACS Applied Materials & Interfaces
Da Yao, Peigui Gu, Youyu Wang, Weibin Luo, Huiliang Chi, Jianjun Ge, Youhui Qian
To assure the faithful chromosome segregation, cells make use of the spindle assembly checkpoint (SAC), which can be activated in aneuploidy cancer cells. In this study, the efficacies of inhibiting Polo-like kinase 1 (PLK1) on the radiosensitization of non-small cell lung cancer (NSCLC) cells were studied. Clonogenic survival assay was performed to identify the effects of the PLK1 inhibitor on radiosensitivity within NSCLC cells. Mitotic catastrophe assessment was used to measure the cell death and γH2AX foci were utilized to assess the DNA double-strand breaks (DSB)...
October 17, 2017: Biochemistry and Cell Biology, Biochimie et Biologie Cellulaire
Abdulla Al Mamun Bhuyan, A K M Ashiqul Haque, Itishri Sahu, Hang Cao, Michael S D Kormann, Florian Lang
BACKGROUND/AIMS: The Polo-like kinase 1 (Plk1) inhibitor volasertib is used in the treatment of malignancy. Volasertib is partially effective by triggering suicidal death or apoptosis of tumor cells. Similar to apoptosis of nucleated cells, erythrocytes may enter suicidal cell death or eryptosis, which is characterized by cell membrane scrambling with phosphatidylserine translocation to the cell surface and by cell shrinkage. Stimulators of eryptosis include energy depletion, hyperosmotic shock, oxidative stress and excessive increase of cytosolic Ca2+ activity ([Ca2+]i)...
2017: Cellular Physiology and Biochemistry
Rahul Agarwal, Jitendra Narayan, Amitava Bhattacharyya, Mayank Saraswat, Anil Kumar Tomar
A very low 5-year survival rate among hepatocellular carcinoma (HCC) patients is mainly due to lack of early stage diagnosis, distant metastasis and high risk of postoperative recurrence. Hence ascertaining novel biomarkers for early diagnosis and patient specific therapeutics is crucial and urgent. Here, we have performed a comprehensive analysis of the expression data of 423 HCC patients (373 tumors and 50 controls) downloaded from The Cancer Genome Atlas (TCGA) followed by pathway enrichment by gene ontology annotations, subtype classification and overall survival analysis...
October 2017: Cancer Genetics
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