51
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Roy R, Durie D, Li H, Liu BQ, Skehel JM, Mauri F, Cuorvo LV, Barbareschi M, Guo L, Holcik M, Seckl MJ, Pardo OE. hnRNPA1 couples nuclear export and translation of specific mRNAs downstream of FGF-2/S6K2 signalling. Nucleic Acids Res 2014; 42:12483-97. [PMID: 25324306 PMCID: PMC4227786 DOI: 10.1093/nar/gku953] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 09/26/2014] [Accepted: 09/29/2014] [Indexed: 01/14/2023] Open
Abstract
The increased cap-independent translation of anti-apoptotic proteins is involved in the development of drug resistance in lung cancer but signalling events regulating this are poorly understood. Fibroblast growth factor 2 (FGF-2) signalling-induced S6 kinase 2 (S6K2) activation is necessary, but the downstream mediator(s) coupling this kinase to the translational response is unknown. Here, we show that S6K2 binds and phosphorylates hnRNPA1 on novel Ser4/6 sites, increasing its association with BCL-XL and XIAP mRNAs to promote their nuclear export. In the cytoplasm, phosphoS4/6-hnRNPA1 dissociates from these mRNAs de-repressing their IRES-mediated translation. This correlates with the phosphorylation-dependent association of hnRNPA1 with 14-3-3 leading to hnRNPA1 sumoylation on K183 and its re-import into the nucleus. A non-phosphorylatible, S4/6A mutant prevented these processes, hindering the pro-survival activity of FGF-2/S6K2 signalling. Interestingly, immunohistochemical staining of lung and breast cancer tissue samples demonstrated that increased S6K2 expression correlates with decreased cytoplasmic hnRNPA1 and increased BCL-XL expression. In short, phosphorylation on novel N-term sites of hnRNPA1 promotes translation of anti-apoptotic proteins and is indispensable for the pro-survival effects of FGF-2.
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Affiliation(s)
- Rajat Roy
- Division of Cancer, Department of Surgery and Cancer, 1st Floor, ICTEM Building, Hammersmith Hospitals Campus of Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Danielle Durie
- Apoptosis Research Centre, Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada
| | - Hui Li
- Department of Biochemistry, Wuhan University, Wuhan, China
| | - Bing-Qian Liu
- Department of Biochemistry, Wuhan University, Wuhan, China
| | - John Mark Skehel
- Protein Analysis and Proteomics Laboratory, London Research Institute, South Mimms, EN6 3LD, UK
| | - Francesco Mauri
- Department of Histopathology, Hammersmith Hospital Campus, Imperial College, London W120NN, UK
| | | | | | - Lin Guo
- Department of Biochemistry, Wuhan University, Wuhan, China
| | - Martin Holcik
- Apoptosis Research Centre, Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada
| | - Michael J Seckl
- Division of Cancer, Department of Surgery and Cancer, 1st Floor, ICTEM Building, Hammersmith Hospitals Campus of Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Olivier E Pardo
- Division of Cancer, Department of Surgery and Cancer, 1st Floor, ICTEM Building, Hammersmith Hospitals Campus of Imperial College London, Du Cane Road, London W12 0NN, UK
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52
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Mrozowski RM, Sandusky ZM, Vemula R, Wu B, Zhang Q, Lannigan DA, O'Doherty GA. De novo synthesis and biological evaluation of C6″-substituted C4″-amide analogues of SL0101. Org Lett 2014; 16:5996-9. [PMID: 25372628 PMCID: PMC4251525 DOI: 10.1021/ol503012k] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
![]()
In an effort to improve
upon the in vivo half-life
of the known ribosomal s6 kinase (RSK) inhibitor SL0101, C4″-amide/C6″-alkyl
substituted analogues of SL0101 were synthesized and evaluated in
cell-based assays. The analogues were prepared using a de novo asymmetric
synthetic approach, which featured Pd-π-allylic catalyzed glycosylation
for the introduction of a C4″-azido group. Surprisingly replacement
of the C4″-acetate with a C4″-amide resulted in analogues
that were no longer specific for RSK in cell-based assays.
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Affiliation(s)
- Roman M Mrozowski
- Departments of Pathology, Microbiology & Immunology and ⊥Cancer Biology, Vanderbilt University School of Medicine , Nashville, Tennessee 37232, United States
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Zang W, Wang T, Wang Y, Li M, Xuan X, Ma Y, Du Y, Liu K, Dong Z, Zhao G. Myricetin exerts anti-proliferative, anti-invasive, and pro-apoptotic effects on esophageal carcinoma EC9706 and KYSE30 cells via RSK2. Tumour Biol 2014; 35:12583-92. [PMID: 25192723 DOI: 10.1007/s13277-014-2579-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Accepted: 08/29/2014] [Indexed: 01/06/2023] Open
Abstract
Myricetin, a common dietary flavonoid, is widely distributed in fruits and vegetables and is used as a health food supplement based on its anti-tumor properties. However, the effect and mechanisms of myricetin in esophageal carcinoma are not fully understood. Here, we demonstrated the effect of myricetin on the proliferation, apoptosis, and invasion of the esophageal carcinoma cell lines EC9706 and KYSE30 and explored the underlying mechanism and target protein(s) of myricetin. CCK-8 assay, transwell invasion assay, wound-healing assay, cell cycle analysis, and apoptosis assay were used to evaluate the effects of myricetin on cell proliferation, invasion, and apoptosis. Nude mouse tumor xenograft model was built to understand the interaction between myricetin and NTD RSK2. Pull-down assay was used to verify molecular mechanism. Myricetin inhibited proliferation and invasion and induced apoptosis of EC9706 and KYSE30 cells. Moreover, myricetin was shown to bind RSK2 through the NH2-terminal kinase domain. Finally, myricetin inhibited EC9706 and KYSE30 cell proliferation through Mad1 and induced cell apoptosis via Bad. Myricetin inhibits the proliferation and invasion and induces apoptosis in EC9706 and KYSE30 cells via RSK2. Myricetin exerts anti-proliferative, anti-invasive, and pro-apoptotic effects on esophageal carcinoma EC9706 and KYSE30 cells via RSK2. Our results provide novel insight into myricetin as a potential agent for the prevention and treatment of esophageal carcinoma.
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Affiliation(s)
- Wenqiao Zang
- College of Basic Medical Sciences, Zhengzhou University, No. 100 Kexue Road, Zhengzhou, 450001, China
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54
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Phosphorylation of RSK2 at Tyr529 by FGFR2-p38 enhances human mammary epithelial cells migration. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2461-70. [PMID: 25014166 DOI: 10.1016/j.bbamcr.2014.06.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 06/29/2014] [Accepted: 06/30/2014] [Indexed: 01/08/2023]
Abstract
The members of p90 ribosomal S6 kinase (RSK) family of Ser/Thr kinases are downstream effectors of MAPK/ERK pathway that regulate diverse cellular processes including cell growth, proliferation and survival. In carcinogenesis, RSKs are thought to modulate cell motility, invasion and metastasis. Herein, we have studied an involvement of RSKs in FGF2/FGFR2-driven behaviours of mammary epithelial and breast cancer cells. We found that both silencing and inhibiting of FGFR2 attenuated phosphorylation of RSKs, whereas FGFR2 overexpression and/or its stimulation with FGF2 enhanced RSKs activity. Moreover, treatment with ERK, Src and p38 inhibitors revealed that p38 kinase acts as an upstream RSK2 regulator. We demonstrate for the first time that in FGF2/FGFR2 signalling, p38 but not MEK/ERK, indirectly activated RSK2 at Tyr529, which facilitated phosphorylation of its other residues (Thr359/Ser363, Thr573 and Ser380). In contrast to FGF2-triggered signalling, inhibition of p38 in the EGF pathway affected only RSK2-Tyr529, without any impact on the remaining RSK phosphorylation sites. p38-mediated phosphorylation of RSK2-Tyr529 was crucial for the transactivation of residues located at kinase C-terminal domain and linker-region, specifically, in the FGF2/FGFR2 signalling pathway. Furthermore, we show that FGF2 promoted anchorage-independent cell proliferation, formation of focal adhesions and cell migration, which was effectively abolished by treatment with RSKs inhibitor (FMK). These indicate that RSK2 activity is indispensable for FGF2/FGFR2-mediated cellular effects. Our findings identified a new FGF2/FGFR2-p38-RSK2 pathway, which may play a significant role in the pathogenesis and progression of breast cancer and, hence, may present a novel therapeutic target in the treatment of FGFR2-expressing tumours.
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55
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Duan RB, Zhang L, Chen DF, Yang F, Yang JS, Yang WJ. Two p90 ribosomal S6 kinase isoforms are involved in the regulation of mitotic and meiotic arrest in Artemia. J Biol Chem 2014; 289:16006-15. [PMID: 24755224 DOI: 10.1074/jbc.m114.553370] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
There are multiple isoforms of p90 ribosomal S6 kinase (RSK), which regulate diverse cellular functions such as cell growth, proliferation, maturation, and motility. However, the relationship between the structures and functions of RSK isoforms remains undetermined. Artemia is a useful model in which to study cell cycle arrest because these animals undergo prolonged diapauses, a state of obligate dormancy. A novel RSK isoform was identified in Artemia, which was termed Ar-Rsk2. This isoform was compared with an RSK isoform that we previously identified in Artemia, termed Ar-Rsk1. Ar-Rsk2 has an ERK-docking motif, whereas Ar-Rsk1 does not. Western blot analysis revealed that Ar-Rsk1 was activated by phosphorylation, which blocked meiosis in oocytes. Knockdown of Ar-Rsk1 reduced the level of phosphorylated cdc2 and thereby suppressed cytostatic factor activity. This indicates that Ar-Rsk1 regulates the cytostatic factor in meiosis. Expression of Ar-Rsk2 was down-regulated in Artemia cysts in which mitosis was arrested. Knockdown of Ar-Rsk2 resulted in decreased levels of cyclin D3 and phosphorylated histone H3, and the production of pseudo-diapause cysts. This indicates that Ar-Rsk2 regulates mitotic arrest. PLK and ERK RNAi showed that Ar-Rsk2, but not Ar-Rsk1, could be activated by PLK-ERK in Artemia. This is the first study to report that RSK isoforms with and without an ERK-docking motif regulate mitosis and meiosis, respectively. This study provides insight into the relationship between the structures and functions of RSK isoforms.
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Affiliation(s)
- Ru-Bing Duan
- From the Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Li Zhang
- From the Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - 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, Zhejiang 310058, China
| | - Fan Yang
- From the Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - 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, Zhejiang 310058, China
| | - 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, Zhejiang 310058, China
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56
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Nam HJ, Lee IJ, Jang S, Bae CD, Kwak SJ, Lee JH. p90 ribosomal S6 kinase 1 (RSK1) isoenzyme specifically regulates cytokinesis progression. Cell Signal 2014; 26:208-19. [DOI: 10.1016/j.cellsig.2013.11.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 11/08/2013] [Accepted: 11/14/2013] [Indexed: 10/26/2022]
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57
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Döppler H, Storz P. Regulation of VASP by phosphorylation: consequences for cell migration. Cell Adh Migr 2013; 7:482-6. [PMID: 24401601 DOI: 10.4161/cam.27351] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Phosphorylations control all aspects of vasodilator-stimulated phospho-protein (VASP) function. Mapped phosphorylation sites include Y39, S157, S239, T278, and S322, and multiple kinases have been shown to mediate their phosphorylation. Recently, Protein Kinase D1 (PKD1) as a direct kinase for S157 and S322 joined this group. While S157 phosphorylation generally seems to serve as a signal for membrane localization, phosphorylations at S322 or at S239 and T278 have opposite effects on F-actin accumulation. In migrating cells, S322 phosphorylation increases filopodia numbers and length, while S239/T278 phosphorylations decrease these and also disrupt formation of focal adhesions. Therefore, the kinases mediating these phosphorylations can be seen as switches needed to facilitate cell motility.
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Affiliation(s)
- Heike Döppler
- Department of Cancer Biology; Mayo Clinic Comprehensive Cancer Center; Mayo Clinic; Jacksonville, FL USA
| | - Peter Storz
- Department of Cancer Biology; Mayo Clinic Comprehensive Cancer Center; Mayo Clinic; Jacksonville, FL USA
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58
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Planck M, Edlund K, Botling J, Micke P, Isaksson S, Staaf J. Genomic and transcriptional alterations in lung adenocarcinoma in relation to EGFR and KRAS mutation status. PLoS One 2013; 8:e78614. [PMID: 24205279 PMCID: PMC3812039 DOI: 10.1371/journal.pone.0078614] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 09/13/2013] [Indexed: 11/18/2022] Open
Abstract
Introduction In lung adenocarcinoma, the mutational spectrum is dominated by EGFR and KRAS mutations. Improved knowledge about genomic and transcriptional alterations in and between mutation-defined subgroups may identify genes involved in disease development or progression. Methods Genomic profiles from 457 adenocarcinomas, including 113 EGFR-mutated, 134 KRAS-mutated and 210 EGFR and KRAS-wild type tumors (EGFRwt/KRASwt), and gene expression profiles from 914 adenocarcinomas, including 309 EGFR-mutated, 192 KRAS-mutated, and 413 EGFRwt/KRASwt tumors, were assembled from different repositories. Genomic and transcriptional differences between the three mutational groups were analyzed by both supervised and unsupervised methods. Results EGFR-mutated adenocarcinomas displayed a larger number of copy number alterations and recurrent amplifications, a higher fraction of total loss-of-heterozygosity, higher genomic complexity, and a more distinct expression pattern than EGFR-wild type adenocarcinomas. Several of these differences were also consistent when the three mutational groups were stratified by stage, gender and smoking status. Specific copy number alterations were associated with mutation status, predominantly including regions of gain with the highest frequency in EGFR-mutated tumors. Differential regions included both large and small regions of gain on 1p, 5q34-q35.3, 7p, 7q11.21, 12p12.1, 16p, and 21q, and losses on 6q16.3-q21, 8p, and 9p, with 20-40% frequency differences between the mutational groups. Supervised gene expression analyses identified 96 consistently differentially expressed genes between the mutational groups, and together with unsupervised analyses these analyses highlighted the difficulty in broadly resolving the three mutational groups into distinct transcriptional entities. Conclusions We provide a comprehensive overview of the genomic and transcriptional landscape in lung adenocarcinoma stratified by EGFR and KRAS mutations. Our analyses suggest that the overall genomic and transcriptional landscape of lung adenocarcinoma is affected, but only to a minor extent, by EGFR and KRAS mutation status.
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Affiliation(s)
- Maria Planck
- Department of Oncology, Clinical Sciences, Lund University and Skåne University Hospital, Medicon Village, Lund, Sweden
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59
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Wang T, Xuan X, Li M, Gao P, Zheng Y, Zang W, Zhao G. Astragalus saponins affect proliferation, invasion and apoptosis of gastric cancer BGC-823 cells. Diagn Pathol 2013; 8:179. [PMID: 24152941 PMCID: PMC3818446 DOI: 10.1186/1746-1596-8-179] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Accepted: 10/22/2013] [Indexed: 12/19/2022] Open
Abstract
Background Astragalus memebranaceus is a traditional Chinese herbal medicine used in treatment of common cold, diarrhea, fatigue, anorexia and cardiac diseases. Recently, there are growing evidences that Astragalus extract may be a potential anti-tumorigenic agent. Some research showed that the total saponins obtained from Astragalus membranaceus possess significant antitumorigenic activity. Gastric cancer is one of the most frequent cancers in the world, almost two-thirds of gastric cancer cases and deaths occur in less developed regions. But the effect of Astragalus membranaceus on proliferation, invasion and apoptosis of gastric cancer BGC-823 cells remains unclear. Methods Astragalus saponins were extracted. Cells proliferation was determined by CCK-8 assay. Cell cycle and apoptosis were detected by the flow cytometry. Boyden chamber was used to evaluate the invasion and metastasis capabilities of BGC-823 cells. Tumor growth was assessed by subcutaneous inoculation of cells into BALB/c nude mice. Results The results demonstrated that total Astragalus saponins could inhibit human gastric cancer cell growth both in vitro and in vivo, in additional, Astragalus saponins deceased the invasion ability and induced the apoptosis of gastric cancer BGC-823 cells. Conclusions Total Astragalus saponins inhibited human gastric cancer cell growth, decreased the invasion ability and induced the apoptosis. This suggested the possibility of further developing Astragalus as an alternative treatment option, or perhaps using it as adjuvant chemotherapeutic agent in gastric cancer therapy.
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Affiliation(s)
| | | | | | | | | | - Wenqiao Zang
- Department of Microbiology and Immunology, College of Basic Medical Sciences, Zhengzhou University, Zhengzhou, People's Republic of China.
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Abstract
Metastasis, the spreading of cancer cells from a primary tumor to secondary sites throughout the body, is the primary cause of death for patients with cancer. New therapies that prevent invasion and metastasis in combination with current treatments could therefore significantly reduce cancer recurrence and morbidity. Metastasis is driven by altered signaling pathways that induce changes in cell-cell adhesion, the cytoskeleton, integrin function, protease expression, epithelial-to-mesenchymal transition and cell survival. The ribosomal S6 kinase (RSK) family of kinases is a group of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) effectors that can regulate these steps of metastasis by phosphorylating both nuclear and cytoplasmic targets. However, our understanding of RSK function in metastasis remains incomplete and is complicated by the fact that the four RSK isoforms perform nonredundant, sometimes opposing functions. Although some isoforms promote cell motility and invasion by altering transcription and integrin activity, others impair cell motility and invasion through effects on the actin cytoskeleton. The mechanism of RSK action depends both on the isoform and the cancer type. However, despite the variance in RSK-mediated outcomes, chemical inhibition of this group of kinases has proven effective in blocking invasion and metastasis of several solid tumors in preclinical models. RSKs are therefore a promising drug target for antimetastatic cancer treatments that could supplement and improve current therapeutic approaches. This review highlights contradiction and agreement in the current data on the function of RSK isoforms in metastasis and suggests ways forward in developing RSK inhibitors as new antimetastasis drugs.
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Affiliation(s)
- Florian J Sulzmaier
- Authors' Affiliation: Cancer Biology Program, University of Hawaii Cancer Center, University of Hawaii at Manoa, Honolulu, Hawaii
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61
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Tobia C, Gariano G, De Sena G, Presta M. Zebrafish embryo as a tool to study tumor/endothelial cell cross-talk. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1371-7. [DOI: 10.1016/j.bbadis.2013.01.016] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 01/14/2013] [Accepted: 01/17/2013] [Indexed: 01/20/2023]
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Lara R, Seckl MJ, Pardo OE. The p90 RSK family members: common functions and isoform specificity. Cancer Res 2013; 73:5301-8. [PMID: 23970478 DOI: 10.1158/0008-5472.can-12-4448] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The p90 ribosomal S6 kinases (RSK) are implicated in various cellular processes, including cell proliferation, survival, migration, and invasion. In cancer, RSKs modulate cell transformation, tumorigenesis, and metastasis. Indeed, changes in the expression of RSK isoforms have been reported in several malignancies, including breast, prostate, and lung cancers. Four RSK isoforms have been identified in humans on the basis of their high degree of sequence homology. Although this similarity suggests some functional redundancy between these proteins, an increasing body of evidence supports the existence of isoform-based specificity among RSKs in mediating particular cellular processes. This review briefly presents the similarities between RSK family members before focusing on the specific function of each of the isoforms and their involvement in cancer progression.
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Affiliation(s)
- Romain Lara
- Division of Oncology, Oncology Imperial College London, London, United Kingdom
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63
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Utepbergenov D, Derewenda ZS. The unusual mechanism of inhibition of the p90 ribosomal S6 kinase (RSK) by flavonol rhamnosides. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:1285-91. [PMID: 23541530 DOI: 10.1016/j.bbapap.2013.03.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 03/19/2013] [Indexed: 12/21/2022]
Abstract
All known protein kinases share a bilobal kinase domain with well conserved structural elements. Because of significant structural similarities of nucleotide binding pocket, the development of highly selective kinase inhibitors is a very challenging task. Flavonols, naturally occurring plant metabolites, have long been known to inhibit kinases by mimicking the adenine moiety. Interestingly, recent data show that some flavonol glycosides are more selective, although underlying mechanisms were unknown. Crystallographic data from our laboratory revealed that the N-terminal kinase domain of p90 ribosomal S6 kinase, isoform 2, binds three different flavonol rhamnosides in a highly unusual manner, distinct from other kinase inhibitor interactions. The kinase domain undergoes a reorganization of several structural elements in response to the binding of the inhibitors. Specifically, the main β-sheet of the N-lobe undergoes a twisting rotation by ~56° around an axis passing through the N- and C-lobes, leading to the restructuring of the canonical ATP-binding pocket into pockets sterically adapted to the inhibitor shape. The flavonol rhamnosides appear to adopt compact, but strained conformations with the rhamnose moiety swept under the B-ring of flavonol, unlike the structure of the free counterparts in solution. These data suggest that the flavonol glycoside scaffold could be used as a template for new inhibitors selective for the RSK family. This article is part of a Special Issue entitled: Inhibitors of Protein Kinases (2012).
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Affiliation(s)
- Darkhan Utepbergenov
- Department of Molecular Physiology & Biological Physics, University of Virginia, Charlottesville, PO Box 800736, VA 22908, USA
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64
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Weiger MC, Vedham V, Stuelten CH, Shou K, Herrera M, Sato M, Losert W, Parent CA. Real-time motion analysis reveals cell directionality as an indicator of breast cancer progression. PLoS One 2013; 8:e58859. [PMID: 23527039 PMCID: PMC3602596 DOI: 10.1371/journal.pone.0058859] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 02/07/2013] [Indexed: 11/18/2022] Open
Abstract
Cancer cells alter their migratory properties during tumor progression to invade surrounding tissues and metastasize to distant sites. However, it remains unclear how migratory behaviors differ between tumor cells of different malignancy and whether these migratory behaviors can be utilized to assess the malignant potential of tumor cells. Here, we analyzed the migratory behaviors of cell lines representing different stages of breast cancer progression using conventional migration assays or time-lapse imaging and particle image velocimetry (PIV) to capture migration dynamics. We find that the number of migrating cells in transwell assays, and the distance and speed of migration in unconstrained 2D assays, show no correlation with malignant potential. However, the directionality of cell motion during 2D migration nicely distinguishes benign and tumorigenic cell lines, with tumorigenic cell lines harboring less directed, more random motion. Furthermore, the migratory behaviors of epithelial sheets observed under basal conditions and in response to stimulation with epidermal growth factor (EGF) or lysophosphatitic acid (LPA) are distinct for each cell line with regard to cell speed, directionality, and spatiotemporal motion patterns. Surprisingly, treatment with LPA promotes a more cohesive, directional sheet movement in lung colony forming MCF10CA1a cells compared to basal conditions or EGF stimulation, implying that the LPA signaling pathway may alter the invasive potential of MCF10CA1a cells. Together, our findings identify cell directionality as a promising indicator for assessing the tumorigenic potential of breast cancer cell lines and show that LPA induces more cohesive motility in a subset of metastatic breast cancer cells.
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Affiliation(s)
- Michael C. Weiger
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Vidya Vedham
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Christina H. Stuelten
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Karen Shou
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mark Herrera
- Department of Physics, University of Maryland, College Park, Maryland, United States of America
| | - Misako Sato
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Wolfgang Losert
- Department of Physics, University of Maryland, College Park, Maryland, United States of America
| | - Carole A. Parent
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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65
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Gawecka JE, Young-Robbins SS, Sulzmaier FJ, Caliva MJ, Heikkilä MM, Matter ML, Ramos JW. RSK2 protein suppresses integrin activation and fibronectin matrix assembly and promotes cell migration. J Biol Chem 2012; 287:43424-37. [PMID: 23118220 PMCID: PMC3527930 DOI: 10.1074/jbc.m112.423046] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Modulation of integrin activation is important in many cellular functions including adhesion, migration, and assembly of the extracellular matrix. RSK2 functions downstream of Ras/Raf and promotes tumor cell motility and metastasis. We therefore investigated whether RSK2 affects integrin function. We report that RSK2 mediates Ras/Raf inactivation of integrins. As a result, we find that RSK2 impairs cell adhesion and integrin-mediated matrix assembly and promotes cell motility. Active RSK2 appears to affect integrins by reducing actin stress fibers and disrupting focal adhesions. Moreover, RSK2 co-localizes with the integrin activator talin and is present at integrin cytoplasmic tails. It is thereby in a position to modulate integrin activation and integrin-mediated migration. Activation of RSK2 promotes filamin phosphorylation and binding to integrins. We also find that RSK2 is activated in response to integrin ligation to fibronectin. Thus, RSK2 could participate in a feedback loop controlling integrin function. These results reveal RSK2 as a key regulator of integrin activity and provide a novel mechanism by which it may promote cell migration and cancer metastasis.
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Affiliation(s)
- Joanna E Gawecka
- Cancer Biology Program, University of Hawaii Cancer Center, Honolulu, Hawaii 96813, USA
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Konantz M, Balci TB, Hartwig UF, Dellaire G, André MC, Berman JN, Lengerke C. Zebrafish xenografts as a tool for in vivo studies on human cancer. Ann N Y Acad Sci 2012; 1266:124-37. [PMID: 22901264 DOI: 10.1111/j.1749-6632.2012.06575.x] [Citation(s) in RCA: 165] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The zebrafish has become a powerful vertebrate model for genetic studies of embryonic development and organogenesis and increasingly for studies in cancer biology. Zebrafish facilitate the performance of reverse and forward genetic approaches, including mutagenesis and small molecule screens. Moreover, several studies report the feasibility of xenotransplanting human cells into zebrafish embryos and adult fish. This model provides a unique opportunity to monitor tumor-induced angiogenesis, invasiveness, and response to a range of treatments in vivo and in real time. Despite the high conservation of gene function between fish and humans, concern remains that potential differences in zebrafish tissue niches and/or missing microenvironmental cues could limit the relevance and translational utility of data obtained from zebrafish human cancer cell xenograft models. Here, we summarize current data on xenotransplantation of human cells into zebrafish, highlighting the advantages and limitations of this model in comparison to classical murine models of xenotransplantation.
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Affiliation(s)
- Martina Konantz
- Department of Hematology and Oncology, University of Tübingen Medical Center II, Tübingen, Germany
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67
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van Jaarsveld MTM, Blijdorp ICJ, Boersma AWM, Pothof J, Mathijssen RHJ, Verweij J, Wiemer EAC. The kinase RSK2 modulates the sensitivity of ovarian cancer cells to cisplatin. Eur J Cancer 2012; 49:345-51. [PMID: 23041051 DOI: 10.1016/j.ejca.2012.08.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 08/24/2012] [Indexed: 01/12/2023]
Abstract
Platinum-based chemotherapy (e.g. cisplatin, carboplatin) is standard of care for many types of cancer including ovarian cancer, however, the efficacy of treatment is hampered by the development of therapy resistance. The mechanisms behind platinum resistance are not completely understood. Here, we have investigated the role of the family of p90 Ribosomal S6 kinases (RSK), important downstream mediators of ERK1/2, in the response to cisplatin chemotherapy. Strikingly, whereas treatment with cisplatin did not alter the levels of RSK1 in response to cisplatin treatment, the structurally related RSK2 protein was downregulated in an ovarian cancer cell line (A2780). Furthermore, we found that knockdown of RSK2, in contrast to knockdown of RSK1, gave rise to enhanced cisplatin sensitivity in a cisplatin sensitive as well as a cisplatin-resistant A2780 cell line. These results indicate that RSK2 is regulated in response to cisplatin treatment, and this downregulation may contribute to the cytotoxic action of cisplatin. Since RSK2 is frequently amplified in a growing number of cancers, this may have implications for the sensitivity of these tumours to platinum-based cytotoxics.
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Meyer AS, Hughes-Alford SK, Kay JE, Castillo A, Wells A, Gertler FB, Lauffenburger DA. 2D protrusion but not motility predicts growth factor-induced cancer cell migration in 3D collagen. ACTA ACUST UNITED AC 2012; 197:721-9. [PMID: 22665521 PMCID: PMC3373410 DOI: 10.1083/jcb.201201003] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In breast cancer cells, growth factor stimulation of membrane protrusion was a better predictor of 3D migration than 2D motility, cognate receptor expression, or receptor activation. Growth factor–induced migration is a critical step in the dissemination and metastasis of solid tumors. Although differences in properties characterizing cell migration on two-dimensional (2D) substrata versus within three-dimensional (3D) matrices have been noted for particular growth factor stimuli, the 2D approach remains in more common use as an efficient surrogate, especially for high-throughput experiments. We therefore were motivated to investigate which migration properties measured in various 2D assays might be reflective of 3D migratory behavioral responses. We used human triple-negative breast cancer lines stimulated by a panel of receptor tyrosine kinase ligands relevant to mammary carcinoma progression. Whereas 2D migration properties did not correlate well with 3D behavior across multiple growth factors, we found that increased membrane protrusion elicited by growth factor stimulation did relate robustly to enhanced 3D migration properties of the MDA-MB-231 and MDA-MB-157 lines. Interestingly, we observed this to be a more reliable relationship than cognate receptor expression or activation levels across these and two additional mammary tumor lines.
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Affiliation(s)
- Aaron S Meyer
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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69
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Current World Literature. Curr Opin Support Palliat Care 2012; 6:109-25. [DOI: 10.1097/spc.0b013e328350f70c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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70
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Mrozowski RM, Vemula R, Wu B, Zhang Q, Schroeder BR, Hilinski MK, Clark DE, Hecht SM, O’Doherty GA, Lannigan DA. Improving the affinity of SL0101 for RSK using structure-based design. ACS Med Chem Lett 2012; 4:175-179. [PMID: 23519677 DOI: 10.1021/ml300298v] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Enhanced activity of the Ser/Thr protein kinase, RSK, is associated with transformation and metastasis, which suggests that RSK is an attractive drug target. The natural product, SL0101 (kaempferol 3-O-(3″,4″-di-O-acetyl-α-L-rhamnopyranoside), has been shown to be a RSK selective inhibitor. However, the Ki for SL0101 is 1 μM with a half-life of less than 30 min in vivo. To identify analogues with improved efficacy we designed a set of analogues based on the crystallographic model of SL0101 in complex with the RSK2 N-terminal kinase domain. We identified an analogue with a 5″-n-propyl group on the rhamnose that has > 40-fold improved affinity for RSK relative to SL0101 in an in vitro kinase assay. This analogue preferentially inhibited the proliferation of the human breast cancer line, MCF-7, versus the normal untransformed breast line, MCF-10A, which is consistent with results using SL0101. However, the efficacy of the 5″-n-propyl analogue to inhibit MCF-7 proliferation was only two-fold better than for SL0101, which we hypothesize is due to limited membrane permeability. The improved affinity of the 5″-n-propyl analogue for RSK will aid in the design of future compounds for in vivo use.
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Affiliation(s)
- Roman M. Mrozowski
- Department of Pathology, Microbiology & Immunology, Vanderbilt University, Nashville, Tennessee, United States
| | - Rajender Vemula
- Department of Chemistry,
Northeastern
University, Boston, Massachusetts, United States
| | - Bulan Wu
- Department of Chemistry, West
Virginia University, Morgantown, West Virginia, United States
| | - Qi Zhang
- Department of Chemistry,
Northeastern
University, Boston, Massachusetts, United States
| | | | - Michael K. Hilinski
- Department of Microbiology, Immunology & Cancer Biology, University of Virginia, Charlottesville, Virginia, United States
| | - David E. Clark
- Department of Microbiology, Immunology & Cancer Biology, University of Virginia, Charlottesville, Virginia, United States
| | - Sidney M. Hecht
- Center for
BioEnergetics, Biodesign
Institute, Arizona State University, Tempe, Arizona, United States
| | - George A. O’Doherty
- Department of Chemistry,
Northeastern
University, Boston, Massachusetts, United States
| | - Deborah A. Lannigan
- Department of Pathology, Microbiology & Immunology, Vanderbilt University, Nashville, Tennessee, United States
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Abstract
Lung cancer is a heterogeneous disease clinically, biologically, histologically, and molecularly. Understanding the molecular causes of this heterogeneity, which might reflect changes occurring in different classes of epithelial cells or different molecular changes occurring in the same target lung epithelial cells, is the focus of current research. Identifying the genes and pathways involved, determining how they relate to the biological behavior of lung cancer, and their utility as diagnostic and therapeutic targets are important basic and translational research issues. This article reviews current information on the key molecular steps in lung cancer pathogenesis, their timing, and clinical implications.
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Affiliation(s)
- Jill E Larsen
- Hamon Center for Therapeutic Oncology Research, Simmons Cancer Center, 6000 Harry Hines Boulevard, University of Texas Southwestern Medical Center, Dallas, TX 75390-8593, USA
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72
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Gao X, Chaturvedi D, Patel TB. Localization and retention of p90 ribosomal S6 kinase 1 in the nucleus: implications for its function. Mol Biol Cell 2011; 23:503-15. [PMID: 22130794 PMCID: PMC3268728 DOI: 10.1091/mbc.e11-07-0658] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Ribosomal S6 kinase 1 (RSK1), which plays a critical role in cell survival and proliferation, contains a bipartite nuclear localization sequence that permits its entry into the nucleus. RSK1 is retained in the nucleus via its indirect interactions with AKAP95. Interference with its nuclear entry or retention decreases DNA synthesis. Ribosomal S6 kinase 1 (RSK1) belongs to a family of proteins with two kinase domains. Following activation in the cytoplasm by extracellular signal-regulated kinases (ERK1/2), it mediates the cell-proliferative, cell-growth, and survival-promoting actions of a number of growth factors and other agonists. These diverse biological actions of RSK1 involve regulation of both cytoplasmic and nuclear events. However, the mechanisms that permit nuclear accumulation of RSK1 remain unknown. Here, we show that phosphorylation of RSK1 on S221 is important for its dissociation from the type Iα regulatory subunit of protein kinase A (PKA) in the cytoplasm and that RSK1 contains a bipartite nuclear localization sequence that is necessary for its nuclear entry. Once inside, the active RSK1 is retained in the nucleus via its interactions with PKA catalytic subunit and AKAP95. Mutations of RSK1 that do not affect its activity but disrupt its entry into the nucleus or expression of AKAP95 forms that do not enter the nucleus inhibit the ability of active RSK1 to stimulate DNA synthesis. Our findings identify novel mechanisms by which active RSK1 accumulates in the nucleus and also provide new insights into how AKAP95 orchestrates cell cycle progression.
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Affiliation(s)
- Xianlong Gao
- Department of Molecular Pharmacology and Therapeutics, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA
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