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Zhang Q, Huang X, Yang J, Li M. A novel monoclonal antibody against human GRK6 antigen. Monoclon Antib Immunodiagn Immunother 2015; 34:25-9. [PMID: 25723280 DOI: 10.1089/mab.2014.0071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
G protein-coupled receptor kinase 6 (GRK6) plays a universal role in receptor desensitization, by acting as a receptor-G protein interface, thereby affecting serine/threonine kinases. In this study, a 20-aa-long peptide of human GRK6 C-terminus domain was synthesized and covalently coupled to keyhole limpet hemocyanin (KLH). A mouse monoclonal antibody against human GRK6 (anti-GRK6 MAb) was successfully prepared through hybridoma technique by immunizing BALB/c mice with synthesized GRK6426-446-KLH peptides. A high specificity and affinity strain of hybridoma 5D12 were established. The titer of the purified anti-GRK6 MAb was 1.28 × 10(6) measured by indirect ELISA. Western blot and immunocytochemistry experiments were also applied to characterize the antibody specificity. Antibody absorption assays showed that the anti-GRK6 MAb can be blocked by GRK6426-446 peptides. These results indicated that the antibody could bind to GRK6 antigen specifically. This MAb provides valuable support for further studies on the functional properties of GRK6.
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Affiliation(s)
- Qiang Zhang
- 1 Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University , Chengdu, China
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52
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Homan KT, Larimore KM, Elkins JM, Szklarz M, Knapp S, Tesmer JJG. Identification and structure-function analysis of subfamily selective G protein-coupled receptor kinase inhibitors. ACS Chem Biol 2015; 10:310-9. [PMID: 25238254 PMCID: PMC4301037 DOI: 10.1021/cb5006323] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Selective inhibitors of individual subfamilies of G protein-coupled receptor kinases (GRKs) would serve as useful chemical probes as well as leads for therapeutic applications ranging from heart failure to Parkinson's disease. To identify such inhibitors, differential scanning fluorimetry was used to screen a collection of known protein kinase inhibitors that could increase the melting points of the two most ubiquitously expressed GRKs: GRK2 and GRK5. Enzymatic assays on 14 of the most stabilizing hits revealed that three exhibit nanomolar potency of inhibition for individual GRKs, some of which exhibiting orders of magnitude selectivity. Most of the identified compounds can be clustered into two chemical classes: indazole/dihydropyrimidine-containing compounds that are selective for GRK2 and pyrrolopyrimidine-containing compounds that potently inhibit GRK1 and GRK5 but with more modest selectivity. The two most potent inhibitors representing each class, GSK180736A and GSK2163632A, were cocrystallized with GRK2 and GRK1, and their atomic structures were determined to 2.6 and 1.85 Å spacings, respectively. GSK180736A, developed as a Rho-associated, coiled-coil-containing protein kinase inhibitor, binds to GRK2 in a manner analogous to that of paroxetine, whereas GSK2163632A, developed as an insulin-like growth factor 1 receptor inhibitor, occupies a novel region of the GRK active site cleft that could likely be exploited to achieve more selectivity. However, neither compound inhibits GRKs more potently than their initial targets. This data provides the foundation for future efforts to rationally design even more potent and selective GRK inhibitors.
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Affiliation(s)
- Kristoff T. Homan
- Life
Sciences Institute and the Departments of Pharmacology and Biological
Sciences, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Kelly M. Larimore
- Life
Sciences Institute and the Departments of Pharmacology and Biological
Sciences, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jonathan M. Elkins
- Structural
Genomics Consortium, University of Oxford, Old Road Campus Research Building,
Roosevelt Drive, Oxford OX3 7DQ, United Kingdom
| | - Marta Szklarz
- Structural
Genomics Consortium, University of Oxford, Old Road Campus Research Building,
Roosevelt Drive, Oxford OX3 7DQ, United Kingdom
| | - Stefan Knapp
- Structural
Genomics Consortium, University of Oxford, Old Road Campus Research Building,
Roosevelt Drive, Oxford OX3 7DQ, United Kingdom
- Nuffield
Department of Clinical Medicine, Target Discovery Institute, University of Oxford, NDM Research Building, Roosevelt Drive, Oxford OX3 7FZ, United Kingdom
| | - John J. G. Tesmer
- Life
Sciences Institute and the Departments of Pharmacology and Biological
Sciences, University of Michigan, Ann Arbor, Michigan 48109, United States
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Identification of cereblon-binding proteins and relationship with response and survival after IMiDs in multiple myeloma. Blood 2014; 124:536-45. [PMID: 24914135 DOI: 10.1182/blood-2014-02-557819] [Citation(s) in RCA: 176] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cereblon (CRBN) mediates immunomodulatory drug (IMiD) action in multiple myeloma (MM). Using 2 different methodologies, we identified 244 CRBN binding proteins and established relevance to MM biology by changes in their abundance after exposure to lenalidomide. Proteins most reproducibly binding CRBN (>fourfold vs controls) included DDB1, CUL4A, IKZF1, KPNA2, LTF, PFKL, PRKAR2A, RANGAP1, and SHMT2. After lenalidomide treatment, the abundance of 46 CRBN binding proteins decreased. We focused attention on 2 of these-IKZF1 and IKZF3. IZKF expression is similar across all MM stages or subtypes; however, IKZF1 is substantially lower in 3 of 5 IMiD-resistant MM cell lines. The cell line (FR4) with the lowest IKZF1 levels also harbors a damaging mutation and a translocation that upregulates IRF4, an IKZF target. Clinical relevance of CRBN-binding proteins was demonstrated in 44 refractory MM patients treated with pomalidomide and dexamethasone therapy in whom low IKZF1 gene expression predicted lack of response (0/11 responses in the lowest expression quartile). CRBN, IKZF1, and KPNA2 levels also correlate with significant differences in overall survival. Our study identifies CRBN-binding proteins and demonstrates that in addition to CRBN, IKZF1, and KPNA2, expression can predict survival outcomes.
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Díaz de la Guardia R, Catalina P, Panero J, Elosua C, Pulgarin A, López MB, Ayllón V, Ligero G, Slavutsky I, Leone PE. Expression profile of telomere-associated genes in multiple myeloma. J Cell Mol Med 2014; 16:3009-21. [PMID: 22947336 PMCID: PMC4393729 DOI: 10.1111/j.1582-4934.2012.01628.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 08/14/2012] [Indexed: 12/31/2022] Open
Abstract
To further contribute to the understanding of multiple myeloma, we have focused our research interests on the mechanisms by which tumour plasma cells have a higher survival rate than normal plasma cells. In this article, we study the expression profile of genes involved in the regulation and protection of telomere length, telomerase activity and apoptosis in samples from patients with monoclonal gammopathy of undetermined significance, smouldering multiple myeloma, multiple myeloma (MM) and plasma cell leukaemia (PCL), as well as several human myeloma cell lines (HMCLs). Using conventional cytogenetic and fluorescence in situ hybridization studies, we identified a high number of telomeric associations (TAs). Moreover, telomere length measurements by terminal restriction fragment (TRF) assay showed a shorter mean TRF peak value, with a consistent correlation with the number of TAs. Using gene expression arrays and quantitative PCR we identified the hTERT gene together with 16 other genes directly involved in telomere length maintenance: HSPA9, KRAS, RB1, members of the Small nucleolar ribonucleoproteins family, A/B subfamily of ubiquitously expressed heterogeneous nuclear ribonucleoproteins, and 14-3-3 family. The expression levels of these genes were even higher than those in human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs), which have unlimited proliferation capacity. In conclusion, the gene signature suggests that MM tumour cells are able to maintain stable short telomere lengths without exceeding the short critical length, allowing cell divisions to continue. We propose that this could be a mechanism contributing to MM tumour cells expansion in the bone marrow (BM).
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Affiliation(s)
- Rafael Díaz de la Guardia
- Andalusian Public Health System Biobank, Centro de Investigación Biomédica, Consejería de Salud-Universidad de Granada, Granada, Spain.
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55
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Stewart AK. Multiple myeloma: genome sequencing, drug development and the future outlook. Expert Rev Hematol 2014; 7:9-11. [DOI: 10.1586/17474086.2014.873285] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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56
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James RG, Bosch KA, Kulikauskas RM, Yang PT, Robin NC, Toroni RA, Biechele TL, Berndt JD, von Haller PD, Eng JK, Wolf-Yadlin A, Chien AJ, Moon RT. Protein kinase PKN1 represses Wnt/β-catenin signaling in human melanoma cells. J Biol Chem 2013; 288:34658-70. [PMID: 24114839 PMCID: PMC3843078 DOI: 10.1074/jbc.m113.500314] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Advances in phosphoproteomics have made it possible to monitor changes in protein phosphorylation that occur at different steps in signal transduction and have aided the identification of new pathway components. In the present study, we applied this technology to advance our understanding of the responses of melanoma cells to signaling initiated by the secreted ligand WNT3A. We started by comparing the phosphopeptide patterns of cells treated with WNT3A for different periods of time. Next, we integrated these data sets with the results from a siRNA screen that targeted protein kinases. This integration of siRNA screening and proteomics enabled us to identify four kinases that exhibit altered phosphorylation in response to WNT3A and that regulate a luciferase reporter of β-catenin-responsive transcription (β-catenin-activated reporter). We focused on one of these kinases, an atypical PKC kinase, protein kinase N1 (PKN1). Reducing the levels of PKN1 with siRNAs significantly enhances activation of β-catenin-activated reporter and increases apoptosis in melanoma cell lines. Using affinity purification followed by mass spectrometry, we then found that PKN1 is present in a protein complex with a WNT3A receptor, Frizzled 7, as well as with proteins that co-purify with Frizzled 7. These data establish that the protein kinase PKN1 inhibits Wnt/β-catenin signaling and sensitizes melanoma cells to cell death stimulated by WNT3A.
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Leung-Hagesteijn C, Erdmann N, Cheung G, Keats JJ, Stewart AK, Reece D, Chung KC, Tiedemann RE. Xbp1s-negative tumor B cells and pre-plasmablasts mediate therapeutic proteasome inhibitor resistance in multiple myeloma. Cancer Cell 2013; 24:289-304. [PMID: 24029229 PMCID: PMC4118579 DOI: 10.1016/j.ccr.2013.08.009] [Citation(s) in RCA: 264] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 06/13/2013] [Accepted: 08/13/2013] [Indexed: 12/11/2022]
Abstract
Proteasome inhibitor (PI) resistance mechanisms in multiple myeloma (MM) remain controversial. We report the existence of a progenitor organization in primary MM that recapitulates maturation stages between B cells and plasma cells and that contributes to clinical PI resistance. Xbp1s(-) tumor B cells and pre-plasmablasts survive therapeutic PI, preventing cure, while maturation arrest of MM before the plasmablast stage enables progressive disease on PI treatment. Mechanistically, suppression of Xbp1s in MM is shown to induce bortezomib resistance via de-commitment to plasma cell maturation and immunoglobulin production, diminishing endoplasmic reticulum (ER) front-loading and cytotoxic susceptibility to PI-induced inhibition of ER-associated degradation. These results reveal the tumor progenitor structure in MM and highlight its role in therapeutic failure.
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Affiliation(s)
| | | | - Grace Cheung
- Princess Margaret Cancer Centre, Toronto, ON, Canada
| | | | - A Keith Stewart
- Division of Hematology-Oncology, Mayo Clinic, Scottsdale, AZ, USA
| | - Donna Reece
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- University of Toronto, Toronto, ON, Canada
| | | | - Rodger E Tiedemann
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- University of Toronto, Toronto, ON, Canada
- Contact Information: Dr. Rodger E. Tiedemann, Princess Margaret Cancer Centre, 610 University Ave, Toronto, ON M5G 2M9, Canada, Tel: 416-581-8451, Fax: 416-946-6546,
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58
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Solaimani P, Damoiseaux R, Hankinson O. Genome-wide RNAi high-throughput screen identifies proteins necessary for the AHR-dependent induction of CYP1A1 by 2,3,7,8-tetrachlorodibenzo-p-dioxin. Toxicol Sci 2013; 136:107-19. [PMID: 23997114 DOI: 10.1093/toxsci/kft191] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) has a plethora of physiological roles, and upon dysregulation, carcinogenesis can occur. One target gene of AHR encodes the xenobiotic and drug-metabolizing enzyme CYP1A1, which is inducible by the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) via the AHR. An siRNA library targeted against over 5600 gene candidates in the druggable genome was used to transfect mouse Hepa-1 cells, which were then treated with TCDD, and subsequently assayed for CYP1A1-dependent ethoxyresorufin-o-deethylase (EROD) activity. Following redundant siRNA activity (RSA) statistical analysis, we identified 93 hits that reduced EROD activity with a p value ≤ .005 and substantiated 39 of these as positive hits in a secondary screening using endoribonuclease-prepared siRNAs (esiRNAs). Twelve of the corresponding gene products were subsequently confirmed to be necessary for the induction of CYP1A1 messenger RNA by TCDD. None of the candidates were deficient in aryl hydrocarbon nuclear translocator expression. However 6 gene products including UBE2i, RAB40C, CRYGD, DCTN4, RBM5, and RAD50 are required for the expression of AHR as well as for induction of CYP1A1. We also found 2 gene products, ARMC8 and TCF20, to be required for the induction of CYP1A1, but our data are ambiguous as to whether they are required for the expression of AHR. In contrast, SIN3A, PDC, TMEM5, and CD9 are not required for AHR expression but are required for the induction of CYP1A1, implicating a direct role in Cyp1a1 transcription. Our methods, although applied to Cyp1a1, could be modified for identifying proteins that regulate other inducible genes.
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Affiliation(s)
- Parrisa Solaimani
- * Molecular Toxicology Interdepartmental Program, Department of Pathology and Laboratory Medicine, and the Jonsson Comprehensive Cancer Center and
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59
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Dillon PJ, Gregory SM, Tamburro K, Sanders MK, Johnson GL, Raab-Traub N, Dittmer DP, Damania B. Tousled-like kinases modulate reactivation of gammaherpesviruses from latency. Cell Host Microbe 2013; 13:204-14. [PMID: 23414760 DOI: 10.1016/j.chom.2012.12.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Revised: 10/08/2012] [Accepted: 12/20/2012] [Indexed: 11/30/2022]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is linked to human malignancies. The majority of tumor cells harbor latent virus, and a small percentage undergo spontaneous lytic replication. Both latency and lytic replication are important for viral pathogenesis and spread, but the cellular players involved in the switch between the two viral life-cycle phases are not clearly understood. We conducted a small interfering RNA (siRNA) screen targeting the cellular kinome and identified Tousled-like kinases (TLKs) as cellular kinases that control KSHV reactivation from latency. Upon treatment of latent KSHV-infected cells with siRNAs targeting TLKs, we saw robust viral reactivation. Knockdown of TLKs in latent KSHV-infected cells induced expression of viral lytic proteins and production of infectious virus. TLKs were also found to play a role in regulating reactivation from latency of another related oncogenic gammaherpesvirus, Epstein-Barr virus. Our results establish the TLKs as cellular repressors of gammaherpesvirus reactivation.
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Affiliation(s)
- Patrick J Dillon
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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60
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Li YP. GRK6 expression in patients with hepatocellular carcinoma. ASIAN PAC J TROP MED 2013; 6:220-3. [PMID: 23375037 DOI: 10.1016/s1995-7645(13)60027-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 11/15/2012] [Accepted: 02/15/2013] [Indexed: 01/13/2023] Open
Abstract
OBJECTIVE To investigate the expression and potential roles of G protein-coupled receptor kinase 6 (GRK6) in hepatocellular carcinoma (HCC) patients. METHODS Immunohistochemistry and Western blot was performed to determine GRK6 expression in 73 HCC samples. And the correlation with clinicopathological features was also analyzed. RESULTS GRK6 expression was significantly higher in HCC than that in normal hepatic tissue. GRK6 was positively correlated with proliferation marker Ki-67, clinical stage, metastasis and survival time. CONCLUSIONS Our results suggested that GRK6 overexpression plays an important role in HCC. Monitoring the expression of GRK6 maybe helpful in early diagnosis and prognosis of HCC.
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Affiliation(s)
- Ya-Ping Li
- Department of Infectious Disease, Huanggang Center Hospital, Huanggang 438000, China.
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61
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So CH, Michal A, Komolov KE, Luo J, Benovic JL. G protein-coupled receptor kinase 2 (GRK2) is localized to centrosomes and mediates epidermal growth factor-promoted centrosomal separation. Mol Biol Cell 2013; 24:2795-806. [PMID: 23904266 PMCID: PMC3771943 DOI: 10.1091/mbc.e13-01-0013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
G protein-coupled receptor kinases (GRKs) play a central role in regulating receptor signaling, but recent studies suggest a broader role in modulating normal cellular functions. For example, GRK5 has been shown to localize to centrosomes and regulate microtubule nucleation and cell cycle progression. Here we demonstrate that GRK2 is also localized to centrosomes, although it has no role in centrosome duplication or microtubule nucleation. Of interest, knockdown of GRK2 inhibits epidermal growth factor receptor (EGFR)-mediated separation of duplicated centrosomes. This EGFR/GRK2-mediated process depends on the protein kinases mammalian STE20-like kinase 2 (Mst2) and Nek2A but does not involve polo-like kinase 1. In vitro analysis and dominant-negative approaches reveal that GRK2 directly phosphorylates and activates Mst2. Collectively these findings demonstrate that GRK2 is localized to centrosomes and plays a central role in mitogen-promoted centrosome separation most likely via its ability to phosphorylate Mst2.
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Affiliation(s)
- Christopher H So
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107
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62
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Pan J, Zhang J, Hill A, Lapan P, Berasi S, Bates B, Miller C, Haney S. A kinome-wide siRNA screen identifies multiple roles for protein kinases in hypoxic stress adaptation, including roles for IRAK4 and GAK in protection against apoptosis in VHL-/- renal carcinoma cells, despite activation of the NF-κB pathway. ACTA ACUST UNITED AC 2013; 18:782-96. [PMID: 23591012 DOI: 10.1177/1087057113484803] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Hypoxia induces changes to cancer cells that make them more resistant to treatment. We have looked at signaling pathways that facilitate these changes by screening the human kinome for effects on hypoxic responses in SW480 colon cancer cells. Hits identified in the screen were examined for effects on multiple molecular responses to hypoxia, including the endoplasmic reticulum stress and DNA damage responses in colon, melanoma, and renal cancer lines. To validate the hits from the small interfering RNA studies, we developed cell lines expressing stable short hairpin RNAs (shRNAs) in the A498 renal carcinoma cell line. Several lines, including those expressing shRNAs against DYRK1B, GAK, IHPK2, IRAK4, and MATK, showed an inability to form spheroid cultures. In addition, shRNAs targeting IRAK4 and GAK were incapable of 2D growth under anoxia. In the GAK shRNA-expressing line, nuclear factor-κB (NF-κB) was localized to the nucleus, but in the IRAK4 shRNA line, NF-κB levels were increased but the extent of nuclear localization was unchanged. Dominant negative mutants of IRAK4 and GAK also showed strong apoptotic effects in A498 cells under anoxia, supporting a direct link between these kinases and survival of the VHL(-/-) RCC line, which is typically highly resistant to hypoxic stress as a result of high and constitutive levels of Hif-1α.
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Affiliation(s)
- Jing Pan
- Applied Genomics, Department of Biological Technologies, Wyeth Research, Cambridge, MA, USA
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Mahajan K, Mahajan NP. ACK1 tyrosine kinase: targeted inhibition to block cancer cell proliferation. Cancer Lett 2013; 338:185-92. [PMID: 23597703 DOI: 10.1016/j.canlet.2013.04.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 04/03/2013] [Accepted: 04/08/2013] [Indexed: 01/05/2023]
Abstract
ACK1 tyrosine kinase, located on chromosome 3q29, is aberrantly activated, amplified or mutated in a wide variety of human cancers. While the deregulated kinase is oncogenic and its activation correlates with progression to metastatic stage, its inhibition causes cell cycle arrest, sensitizes cells to ionizing radiation and induces apoptosis. Oncogenicity of ACK1 is not only due to its ability to promote activation of critical pro-survival kinases and harmone receptors by phosphorylating at distinct tyrosine residues, but also by employing a similar mechanism to eliminate a tumor suppressor from cancer cells. Despite the substantial data supporting the oncogenic role of ACK1, and the potential clinical benefit of blocking ACK1 in metastatic disease, to date ACK1-specific small molecule inhibitors have not been exploited for cancer therapy. This review highlights recent advances that elucidate how cancer cells employ ACK1 kinase to their advantage and discusses some of the novel ACK1 inhibitors that have shown promise in pre-clinical studies.
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Affiliation(s)
- Kiran Mahajan
- Drug Discovery Department, Moffitt Cancer Center, 12902 Magnolia Drive, Tampa, FL 33612, USA.
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64
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Santulli G, Trimarco B, Iaccarino G. G-protein-coupled receptor kinase 2 and hypertension: molecular insights and pathophysiological mechanisms. High Blood Press Cardiovasc Prev 2013; 20:5-12. [PMID: 23532739 DOI: 10.1007/s40292-013-0001-8] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 11/06/2012] [Indexed: 12/17/2022] Open
Abstract
Numerous factors partake in the fine-tuning of arterial blood pressure. The heptahelical G-protein-coupled receptors (GPCRs) represent one of the largest classes of cell-surface receptors. Further, ligands directed at GPCRs account for nearly 30 % of current clinical pharmaceutical agents available. Given the wide variety of GPCRs involved in blood pressure control, it is reasonable to speculate for a potential role of established intermediaries involved in the GPCR desensitization process, like the G-protein-coupled receptor kinases (GRKs), in the regulation of vascular tone. Of the seven mammalian GRKs, GRK2 seems to be the most relevant isoform at the cardiovascular level. This review attempts to assemble the currently available information concerning GRK2 and hypertension, opening new potential fields of translational investigation to treat this vexing disease.
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Affiliation(s)
- Gaetano Santulli
- Department of Advanced Biomedical Sciences, Federico II University of Naples, 80131, Naples, Italy.
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Yuan L, Zhang H, Liu J, Rubin JB, Cho YJ, Shu HK, Schniederjan M, MacDonald TJ. Growth factor receptor-Src-mediated suppression of GRK6 dysregulates CXCR4 signaling and promotes medulloblastoma migration. Mol Cancer 2013; 12:18. [PMID: 23497290 PMCID: PMC3599655 DOI: 10.1186/1476-4598-12-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 02/28/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Metastasis in medulloblastoma (MB) is associated with poor survival. Recent genetic studies revealed MB to comprise distinct molecular subgroups, including the sonic hedgehog (SHH) subgroup that exhibits a relatively high rate of progression. To identify targeted therapeutics against metastasis, a better understanding of the regulation of MB cell migration is needed. G protein-coupled receptor kinases (GRKs) have been implicated in cancer metastasis through their regulation of G-protein coupled receptors (GPCRs) involved in growth factor (GF)-mediated cell migration. However, the specific roles and regulation of GRKs in MB have not been investigated. METHODS Microarray mRNA analysis was performed for GRKs, GPCRs, and GFs in 29 human MB, and real time RT-PCR was used to detect GRK6 expression in MB cells. Lenti- or retro-virus infection, and siRNA or shRNA transfection, of MB cells was used to overexpress and knockdown target genes, respectively. Western blot was used to confirm altered expression of proteins. The effect of altered target protein on cell migration was determined by Boyden chamber assay and xCELLigence migration assays. RESULTS We observed co-overexpression of PDGFRA, CXCR4, and CXCL12 in the SHH MB subtype compared to non-SHH MB (5, 7, and 5-fold higher, respectively). GRK6, which typically acts as a negative regulator of CXCR4 signaling, is downregulated in MB, relative to other GRKs, while the percentage of GRK6 expression is lower in MB tumors with metastasis (22%), compared to those without metastasis (43%). In SHH-responsive MB cells, functional blockade of PDGFR abolished CXCR4-mediated signaling. shPDGFR transfected MB cells demonstrated increased GRK6 expression, while PDGF or 10% FBS treatment of native MB cells reduced the stability of GRK6 by inducing its proteosomal degradation. Overexpression or downregulation of Src, a key mediator of GF receptor/PDGFR signaling, similarly inhibited or induced GRK6 expression, respectively. siRNA downregulation of GRK6 enhanced CXCR4 signaling and promoted MB migration, while lentiviral-GRK6 overexpression suppressed CXCR4 signaling, potentiated the effect of AMD3100, a CXCR4 antagonist, and impaired migration. CONCLUSIONS Our findings demonstrate a novel mechanism of GF receptor/PDGFR-Src-mediated dysregulation of CXCR4 signaling that promotes MB cell migration, which could potentially be exploited for therapeutic targeting in SHH MB.
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Affiliation(s)
- Liangping Yuan
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Emory University School of Medicine, 2015 Uppergate Drive NE, Atlanta, GA 30322, USA
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Uncovering the biology of multiple myeloma among African Americans: a comprehensive genomics approach. Blood 2013; 121:3147-52. [PMID: 23422747 DOI: 10.1182/blood-2012-07-443606] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Epidemiological data have suggested that African American (AA) persons are twice as likely to be diagnosed with multiple myeloma (MM) compared with European American (EA) persons. Here, we have analyzed a set of cytogenetic and genomic data derived from AA and EA MM patients. We have compared the frequency of IgH translocations in a series of data from 115 AA patients from 3 studies and 353 EA patients from the Eastern Cooperative Oncology Group (ECOG) studies E4A03 and E9487. We have also interrogated tumors from 45 AA and 196 EA MM patients for somatic copy number abnormalities associated with poor outcome. In addition, 35 AA and 178 EA patients were investigated for a transcriptional profile associated with high-risk disease. Overall, based on this cohort, genetic profiles were similar except for a significantly lower frequency of IgH translocations (40% vs 52%; P = .032) in AA patients. Frequency differences of somatic copy number aberrations were not significant after correction for multiple testing. There was also no significant difference in the frequency of high-risk disease based on gene expression profiling. Our study represents the first comprehensive comparisons of the frequency and distribution of molecular alterations in MM tumors between AA and EA patients. ECOG E4A03 is registered with ClinicalTrials.gov, number NCT00098475. ECOG E9487 is a companion validation set to the ECOG study E9486 and is registered with the National Institutes of Health, National Cancer Institute, Clinical Trials (PDQ), number EST-9486.
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Abstract
Gene silencing by RNA interference (RNAi) has become a standard method for the characterization of gene function in mammalian cells. Short hairpin (sh) RNAs expressed from stably integrated vectors mediate gene knockdown both in cultured cells and in mice, presenting a fast alternative to gene knockout approaches. We describe three strategies to control gene silencing in mice that can be applied to any transcript of interest. This shRNA based approach enables either i) constitutive body-wide knockdown, ii) cell type-specific knockdown controlled by Cre recombinase, or iii) inducible body-wide knockdown controlled by doxycycline. For reliable expression the shRNA vector of interest is inserted into a Rosa26 docking site of ES cells by a site-specific recombinase. These ES cells can then be used to generate shRNA transgenic mice. This technology enables the production of adult knockdown mice within 11 months for an expedite in vivo validation of drug targets.
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68
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Smg1 haploinsufficiency predisposes to tumor formation and inflammation. Proc Natl Acad Sci U S A 2012; 110:E285-94. [PMID: 23277562 DOI: 10.1073/pnas.1215696110] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
SMG1 is a member of the phosphoinositide kinase-like kinase family of proteins that includes ATM, ATR, and DNA-PK, proteins with known roles in DNA damage and cellular stress responses. SMG1 has a well-characterized role in nonsense-mediated decay as well as suggested roles in the DNA damage response, resistance to oxidative stress, regulation of hypoxic responses, and apoptosis. To understand the roles of SMG1 further, we generated a Genetrap Smg1 mouse model. Smg1 homozygous KO mice were early embryonic lethal, but Smg1 heterozygous mice showed a predisposition to a range of cancers, particularly lung and hematopoietic malignancies, as well as development of chronic inflammation. These mice did not display deficiencies in known roles of SMG1, including nonsense-mediated decay. However, they showed elevated basal tissue and serum cytokine levels, indicating low-level inflammation before the development of tumors. Smg1 heterozygous mice also showed evidence of oxidative damage in tissues. These data suggest that the inflammation observed in Smg1 haploinsufficiency contributes to susceptibility to cancer and that Smg1-deficient animals represent a model of inflammation-enhanced cancer development.
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69
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Jan YH, Tsai HY, Yang CJ, Huang MS, Yang YF, Lai TC, Lee CH, Jeng YM, Huang CY, Su JL, Chuang YJ, Hsiao M. Adenylate Kinase-4 Is a Marker of Poor Clinical Outcomes That Promotes Metastasis of Lung Cancer by Downregulating the Transcription Factor ATF3. Cancer Res 2012; 72:5119-29. [DOI: 10.1158/0008-5472.can-12-1842] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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70
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71
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Duan Z, Zhang J, Choy E, Harmon D, Liu X, Nielsen P, Mankin H, Gray NS, Hornicek FJ. Systematic kinome shRNA screening identifies CDK11 (PITSLRE) kinase expression is critical for osteosarcoma cell growth and proliferation. Clin Cancer Res 2012; 18:4580-8. [PMID: 22791884 DOI: 10.1158/1078-0432.ccr-12-1157] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Identification of new targeted therapies is critical to improving the survival rate of patients with osteosarcoma. The goal of this study is to identify kinase based potential therapeutic target in osteosarcomas. EXPERIMENTAL DESIGN We used a lentiviral-based shRNA kinase library to screen for kinases which play a role in osteosarcoma cell survival. The cell proliferation assay was used to evaluate cell growth and survival. siRNA assays were applied to confirm the observed phenotypic changes resulting from the loss of kinase gene expression. CDK11 (PITSLRE) was identified as essential for the survival of osteosarcoma cells, and its expression was confirmed by Western blot analysis and immunohistochemistry. Overall patient survival was correlated with the CDK11 expression and its prognosis. The role of CDK11 expression in sustaining osteosarcoma growth was further evaluated in an osteosarcoma xenograft model in vivo. RESULTS Osteosarcoma cells display high levels of CDK11 expression. CDK11 expression knocked down by either lentiviral shRNA or siRNA inhibit cell growth and induce apoptosis in osteosarcoma cells. Immunohistochemical analysis showed that patients with osteosarcoma with high CDK11 tumor expression levels were associated with significantly shorter survival than patients with osteosarcoma with low level of tumor CDK11 expression. Systemic in vivo administration of in vivo ready siRNA of CDK11 reduced the tumor growth in an osteosarcoma subcutaneous xenograft model. CONCLUSIONS We show that CDK11 signaling is essential in osteosarcoma cell growth and survival, further elucidating the regulatory mechanisms controlling the expression of CDK11 and ultimately develop a CDK11 inhibitor that may provide therapeutic benefit against osteosarcoma.
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Affiliation(s)
- Zhenfeng Duan
- Center for Sarcoma and Connective Tissue Oncology and Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA.
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72
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Bellucci R, Nguyen HN, Martin A, Heinrichs S, Schinzel AC, Hahn WC, Ritz J. Tyrosine kinase pathways modulate tumor susceptibility to natural killer cells. J Clin Invest 2012; 122:2369-83. [PMID: 22684105 PMCID: PMC3386806 DOI: 10.1172/jci58457] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 05/02/2012] [Indexed: 12/13/2022] Open
Abstract
Natural killer (NK) cells are primary effectors of innate immunity directed against transformed tumor cells. In response, tumor cells have developed mechanisms to evade NK cell-mediated lysis through molecular mechanisms that are not well understood. In the present study, we used a lentiviral shRNA library targeting more than 1,000 human genes to identify 83 genes that promote target cell resistance to human NK cell-mediated killing. Many of the genes identified in this genetic screen belong to common signaling pathways; however, none of them have previously been known to modulate susceptibility of human tumor cells to immunologic destruction. Gene silencing of two members of the JAK family (JAK1 and JAK2) increased the susceptibility of a variety of tumor cell types to NK-mediated lysis and induced increased secretion of IFN-γ by NK cells. Treatment of tumor cells with JAK inhibitors also increased susceptibility to NK cell activity. These findings may have important clinical implications and suggest that small molecule inhibitors of tyrosine kinases being developed as therapeutic antitumor agents may also have significant immunologic effects in vivo.
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Affiliation(s)
- Roberto Bellucci
- Department of Medical Oncology, Dana-Farber Cancer Institute (DFCI), Boston, Massachusetts, USA.
Department of Medicine, Brigham and Woman’s Hospital, Boston, Massachusetts, USA.
Harvard Medical School, Boston, Massachusetts, USA.
Department of Pediatric Oncology,
Center for Cancer Genome Discovery, and
Cancer Vaccine Center, DFCI, Boston, Massachusetts, USA
| | - Hong-Nam Nguyen
- Department of Medical Oncology, Dana-Farber Cancer Institute (DFCI), Boston, Massachusetts, USA.
Department of Medicine, Brigham and Woman’s Hospital, Boston, Massachusetts, USA.
Harvard Medical School, Boston, Massachusetts, USA.
Department of Pediatric Oncology,
Center for Cancer Genome Discovery, and
Cancer Vaccine Center, DFCI, Boston, Massachusetts, USA
| | - Allison Martin
- Department of Medical Oncology, Dana-Farber Cancer Institute (DFCI), Boston, Massachusetts, USA.
Department of Medicine, Brigham and Woman’s Hospital, Boston, Massachusetts, USA.
Harvard Medical School, Boston, Massachusetts, USA.
Department of Pediatric Oncology,
Center for Cancer Genome Discovery, and
Cancer Vaccine Center, DFCI, Boston, Massachusetts, USA
| | - Stefan Heinrichs
- Department of Medical Oncology, Dana-Farber Cancer Institute (DFCI), Boston, Massachusetts, USA.
Department of Medicine, Brigham and Woman’s Hospital, Boston, Massachusetts, USA.
Harvard Medical School, Boston, Massachusetts, USA.
Department of Pediatric Oncology,
Center for Cancer Genome Discovery, and
Cancer Vaccine Center, DFCI, Boston, Massachusetts, USA
| | - Anna C. Schinzel
- Department of Medical Oncology, Dana-Farber Cancer Institute (DFCI), Boston, Massachusetts, USA.
Department of Medicine, Brigham and Woman’s Hospital, Boston, Massachusetts, USA.
Harvard Medical School, Boston, Massachusetts, USA.
Department of Pediatric Oncology,
Center for Cancer Genome Discovery, and
Cancer Vaccine Center, DFCI, Boston, Massachusetts, USA
| | - William C. Hahn
- Department of Medical Oncology, Dana-Farber Cancer Institute (DFCI), Boston, Massachusetts, USA.
Department of Medicine, Brigham and Woman’s Hospital, Boston, Massachusetts, USA.
Harvard Medical School, Boston, Massachusetts, USA.
Department of Pediatric Oncology,
Center for Cancer Genome Discovery, and
Cancer Vaccine Center, DFCI, Boston, Massachusetts, USA
| | - Jerome Ritz
- Department of Medical Oncology, Dana-Farber Cancer Institute (DFCI), Boston, Massachusetts, USA.
Department of Medicine, Brigham and Woman’s Hospital, Boston, Massachusetts, USA.
Harvard Medical School, Boston, Massachusetts, USA.
Department of Pediatric Oncology,
Center for Cancer Genome Discovery, and
Cancer Vaccine Center, DFCI, Boston, Massachusetts, USA
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73
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Attacking the genome: emerging siRNA nanocarriers from concept to clinic. Curr Opin Pharmacol 2012; 12:427-33. [PMID: 22726555 DOI: 10.1016/j.coph.2012.05.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 05/16/2012] [Accepted: 05/24/2012] [Indexed: 11/20/2022]
Abstract
Ever since the ground breaking discovery of RNA interference (RNAi), an endogenous mechanism for sequence specific regulation of gene expression via short interfering RNAs (siRNA), researchers and pharmaceutical companies alike have devoted immense time and capital into the design of nanocarriers that can mediate safe and effective delivery. After over a decade of research, a PubMed search for 'siRNA delivery' returns over 2500 references, yet only a handful of delivery systems have been successfully translated to the clinic. This low rate of clinical translation can partly be attributed to the complexity of the barriers that need to be overcome in vivo. Advances in identifying some of these barriers have lead to the development of molecular components that can overcome some of these hurdles. The judicious assembly of these components, as seen in stable nucleic-acid-lipid nanoparticles and the cyclodextrin polymer, will be required for the successful clinical translation of nanoparticle-based siRNA therapeutics.
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74
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So CH, Michal AM, Mashayekhi R, Benovic JL. G protein-coupled receptor kinase 5 phosphorylates nucleophosmin and regulates cell sensitivity to polo-like kinase 1 inhibition. J Biol Chem 2012; 287:17088-17099. [PMID: 22467873 PMCID: PMC3366848 DOI: 10.1074/jbc.m112.353854] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 03/27/2012] [Indexed: 01/14/2023] Open
Abstract
G protein-coupled receptor kinases (GRKs) phosphorylate activated G protein-coupled receptors, leading to their desensitization and endocytosis. GRKs have also been implicated in phosphorylating other classes of proteins and can localize in a variety of cellular compartments, including the nucleus. Here, we attempted to identify potential nuclear substrates for GRK5. Our studies reveal that GRK5 is able to interact with and phosphorylate nucleophosmin (NPM1) both in vitro and in intact cells. NPM1 is a nuclear protein that regulates a variety of cell functions including centrosomal duplication, cell cycle control, and apoptosis. GRK5 interaction with NPM1 is mediated by the N-terminal domain of each protein, and GRK5 primarily phosphorylates NPM1 at Ser-4, a site shared with polo-like kinase 1 (PLK1). NPM1 phosphorylation by GRK5 and PLK1 correlates with the sensitivity of cells to undergo apoptosis with cells having higher GRK5 levels being less sensitive and cells with lower GRK5 being more sensitive to PLK1 inhibitor-induced apoptosis. Taken together, our results demonstrate that GRK5 phosphorylates Ser-4 in nucleophosmin and regulates the sensitivity of cells to PLK1 inhibition.
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Affiliation(s)
- Christopher H So
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Allison M Michal
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Rouzbeh Mashayekhi
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Jeffrey L Benovic
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
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75
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Abstract
Most myeloma patients still experience recurrent relapse and eventually become resistant and/or intolerant of effective agents such as corticosteroids, alkylating agents, immune modulators (lenalidomide and thalidomide) or proteasome inhibitors such as bortezomib. Once this happens average survivals are less than one year. Progress has been made for such patients, however, with the demonstration of clinical benefit of novel proteasome inhibitors (carfilzomib) and immune modulators (pomalidomide). Pomalidomide when used with dexamethasone has activity in 30-60% of patients depending on disease stage. Carfilzomib is an irreversible proteasome inhibitor with favorable toxicity profile (minimal neuropathy) and response rates of 17-54% depending on the disease stage treated. Novel targets are also being explored. Histone deacetylase inhibitors such as vorinostat and panobinostat are in phase II testing although results from a randomized trial combining vorinostat with bortezomib were disappointing. Other small molecules or monoclonal antibodies with novel targets such as kinase inhibitors(AKT, CDK5) and cell surface receptors (e.g. elotuzumab) are undergoing active investigation.
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Affiliation(s)
- A Keith Stewart
- Division of Hematology-Oncology, Mayo Clinic in Arizona, 13400 East Shea Boulevard, Scottsdale, AZ, USA.
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76
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Tiedemann RE, Zhu YX, Schmidt J, Shi CX, Sereduk C, Yin H, Mousses S, Stewart AK. Identification of molecular vulnerabilities in human multiple myeloma cells by RNA interference lethality screening of the druggable genome. Cancer Res 2011; 72:757-68. [PMID: 22147262 DOI: 10.1158/0008-5472.can-11-2781] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Despite recent advances in targeted treatments for multiple myeloma, optimal molecular therapeutic targets have yet to be identified. To functionally identify critical molecular targets, we conducted a genome-scale lethality study in multiple myeloma cells using siRNAs. We validated the top 160 lethal hits with four siRNAs per gene in three multiple myeloma cell lines and two non-myeloma cell lines, cataloging a total of 57 potent multiple myeloma survival genes. We identified the Bcl2 family member MCL1 and several 26S proteasome subunits among the most important and selective multiple myeloma survival genes. These results provided biologic validation of our screening strategy. Other essential targets included genes involved in RNA splicing, ubiquitination, transcription, translation, and mitosis. Several of the multiple myeloma survival genes, especially MCL1, TNK2, CDK11, and WBSCR22, exhibited differential expression in primary plasma cells compared with other human primary somatic tissues. Overall, the most striking differential functional vulnerabilities between multiple myeloma and non-multiple myeloma cells were found to occur within the 20S proteasome subunits, MCL1, RRM1, USP8, and CKAP5. We propose that these genes should be investigated further as potential therapeutic targets in multiple myeloma.
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Affiliation(s)
- Rodger E Tiedemann
- Princess Margaret Hospital, Ontario Cancer Institute and the University of Toronto, Toronto, Ontario, Canada.
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77
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Xie L, Kassner M, Munoz RM, Que QQ, Kiefer J, Zhao Y, Mousses S, Yin HH, Von Hoff DD, Han H. Kinome-wide siRNA screening identifies molecular targets mediating the sensitivity of pancreatic cancer cells to Aurora kinase inhibitors. Biochem Pharmacol 2011; 83:452-61. [PMID: 22100984 DOI: 10.1016/j.bcp.2011.11.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 10/29/2011] [Accepted: 11/04/2011] [Indexed: 01/05/2023]
Abstract
Aurora kinases are a family of mitotic kinases that play important roles in the tumorigenesis of a variety of cancers including pancreatic cancer. A number of Aurora kinase inhibitors (AKIs) are currently being tested in preclinical and clinical settings as anti-cancer therapies. However, the antitumor activity of AKIs in clinical trials has been modest. In order to improve the antitumor activity of AKIs in pancreatic cancer, we utilized a kinome focused RNAi screen to identify genes that, when silenced, would sensitize pancreatic cancer cells to AKI treatment. A total of 17 kinase genes were identified and confirmed as positive hits. One of the hits was the platelet-derived growth factor receptor, alpha polypeptide (PDGFRA), which has been shown to be overexpressed in pancreatic cancer cells and tumor tissues. Imatinib, a PDGFR inhibitor, significantly enhanced the anti-proliferative effect of ZM447439, an Aurora B specific inhibitor, and PHA-739358, a pan-Aurora kinase inhibitor. Further studies showed that imatinib augmented the induction of G2/M cell cycle arrest and apoptosis by PHA-739358. These findings indicate that PDGFRA is a potential mediator of AKI sensitivity in pancreatic cancer cells.
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Affiliation(s)
- Lifang Xie
- Clinical Translational Research Division, Translational Genomic Research Institute (TGen), 13208 E Shea Blvd, Scottsdale, AZ 85259, USA
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78
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Cereblon expression is required for the antimyeloma activity of lenalidomide and pomalidomide. Blood 2011; 118:4771-9. [PMID: 21860026 DOI: 10.1182/blood-2011-05-356063] [Citation(s) in RCA: 478] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The precise molecular mechanism of action and targets through which thalidomide and related immunomodulatory drugs (IMiDs) exert their antitumor effects remains unclear. We investigated the role of cereblon (CRBN), a primary teratogenic target of thalidomide, in the antimyeloma activity of IMiDs. CRBN depletion is initially cytotoxic to human myeloma cells, but surviving cells with stable CRBN depletion become highly resistant to both lenalidomide and pomalidomide, but not to the unrelated drugs bortezomib, dexamethasone, and melphalan. Acquired deletion of CRBN was found to be the primary genetic event differentiating isogenic MM1.S cell lines cultured to be sensitive or resistant to lenalidomide and pomalidomide. Gene expression changes induced by lenalidomide were dramatically suppressed in the presence of CRBN depletion, further demonstrating that CRBN is required for lenalidomide activity. Downstream targets of CRBN include interferon regulatory factor 4 (IRF4) previously reported to also be a target of lenalidomide. Patients exposed to, and putatively resistant to, lenalidomide had lower CRBN levels in paired samples before and after therapy. In summary, CRBN is an essential requirement for IMiD activity and a possible biomarker for the clinical assessment of antimyeloma efficacy.
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79
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Zhang S, Farag SS. From cell biology to therapy: ENMD-2076 in the treatment of multiple myeloma. Expert Opin Investig Drugs 2011; 20:1015-28. [DOI: 10.1517/13543784.2011.584869] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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80
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RNAi screen of the druggable genome identifies modulators of proteasome inhibitor sensitivity in myeloma including CDK5. Blood 2011; 117:3847-57. [PMID: 21289309 DOI: 10.1182/blood-2010-08-304022] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The molecular target(s) cooperating with proteasome inhibition in multiple myeloma (MM) remain unknown. We therefore measured proliferation in MM cells transfected with 13 984 small interfering RNAs in the absence or presence of increasing concentrations of bortezomib. We identified 37 genes, which when silenced, are not directly cytotoxic but do synergistically potentiate the growth inhibitory effects of bortezomib. To focus on bortezomib sensitizers, genes that also sensitized MM to melphalan were excluded. When suppressed, the strongest bortezomib sensitizers were the proteasome subunits PSMA5, PSMB2, PSMB3, and PSMB7 providing internal validation, but others included BAZ1B, CDK5, CDC42SE2, MDM4, NME7, RAB8B, TFE3, TNFAIP3, TNK1, TOP1, VAMP2, and YY1. The strongest hit CDK5 also featured prominently in pathway analysis of primary screen data. Cyclin-dependent kinase 5 (CDK5) is expressed at high levels in MM and neural tissues with relatively low expression in other organs. Viral shRNA knockdown of CDK5 consistently sensitized 5 genetically variable MM cell lines to proteasome inhibitors (bortezomib and carfilzomib). Small-molecule CDK5 inhibitors were demonstrated to synergize with bortezomib to induce cytotoxicity of primary myeloma cells and myeloma cell lines. CDK5 regulation of proteasome subunit PSMB5 was identified as a probable route to sensitization.
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81
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Susa M, Choy E, Liu X, Schwab J, Hornicek FJ, Mankin H, Duan Z. Cyclin G-associated kinase is necessary for osteosarcoma cell proliferation and receptor trafficking. Mol Cancer Ther 2010; 9:3342-50. [PMID: 20881269 DOI: 10.1158/1535-7163.mct-10-0637] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Osteosarcoma is the most frequent primary malignant bone tumor among the children. The advent of neoadjuvant chemotherapy significantly improved the prognosis of patients with osteosarcoma in the 1980s, but it has since plateaued in the past decades. Recently, one of the most researched areas in sarcoma treatment is tyrosine kinases. Here, we describe research on a serine/threonine kinase, cyclin G-associated kinase (GAK), which has not been reported in osteosarcoma previously. In this study, a lentiviral based human shRNA library was utilized to screen for kinases in KHOS and U-2OS osteosarcoma cells. The expression of GAK was examined in osteosarcoma and the effect on cell proliferation was analyzed by GAK siRNA knockdown. The level of GAK expression and its correlation to prognosis was analyzed in osteosarcoma tissue microarray. The effect of GAK depletion on insulin-like growth factor and epidermal growth factor receptor-mediated signal transduction was analyzed by Western blot. We observed that GAK was overexpressed in both osteosarcoma cell lines and tissue samples when compared with human osteoblasts. GAK knockdown by siRNA decreased cell proliferation in both drug-sensitive and multidrug-resistant osteosarcoma cell lines. Immunohistochemistry of osteosarcoma tissue microarray revealed that overexpression of GAK was associated with poor prognosis. Finally, knockdown of GAK resulted in alterations of receptor trafficking and several downstream proteins. In conclusion, our results suggest that osteosarcoma cell proliferation and survival are dependent on GAK. These findings may lead to the development of new therapeutic options for osteosarcoma.
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Affiliation(s)
- Michiro Susa
- Department of Orthopaedic Surgery, and SarcomaBiology Laboratory, Center for Sarcoma and Connective Tissue Oncology, Massachusetts General Hospital, Boston, MA 02114, USA
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82
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Abstract
Advances in the generation and interpretation of proteomics data have spurred a transition from focusing on protein identification to functional analysis. Here we review recent proteomics results that have elucidated new aspects of the roles and regulation of signal transduction pathways in cancer using the epidermal growth factor receptor (EGFR), ERK and breakpoint cluster region (BCR)-ABL1 networks as examples. The emerging theme is to understand cancer signalling as networks of multiprotein machines which process information in a highly dynamic environment that is shaped by changing protein interactions and post-translational modifications (PTMs). Cancerous genetic mutations derange these protein networks in complex ways that are tractable by proteomics.
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Affiliation(s)
- Walter Kolch
- Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
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83
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Murga C, Penela P, Ribas C, Mayor F. G protein-coupled receptor kinases: Specific phosphorylation of 7TM receptors and beyond. DRUG DISCOVERY TODAY. TECHNOLOGIES 2010; 7:e1-e94. [PMID: 24103684 DOI: 10.1016/j.ddtec.2010.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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