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Valenzuela A, Tardiveau C, Ayuso M, Buyssens L, Bars C, Van Ginneken C, Fant P, Leconte I, Braendli-Baiocco A, Parrott N, Schmitt G, Tessier Y, Barrow P, Van Cruchten S. Safety Testing of an Antisense Oligonucleotide Intended for Pediatric Indications in the Juvenile Göttingen Minipig, including an Evaluation of the Ontogeny of Key Nucleases. Pharmaceutics 2021; 13:1442. [PMID: 34575518 PMCID: PMC8470776 DOI: 10.3390/pharmaceutics13091442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/06/2021] [Accepted: 09/07/2021] [Indexed: 11/16/2022] Open
Abstract
The adult Göttingen Minipig is an acknowledged model for safety assessment of antisense oligonucleotide (ASO) drugs developed for adult indications. To assess whether the juvenile Göttingen Minipig is also a suitable nonclinical model for pediatric safety assessment of ASOs, we performed an 8-week repeat-dose toxicity study in different age groups of minipigs ranging from 1 to 50 days of age. The animals received a weekly dose of a phosphorothioated locked-nucleic-acid-based ASO that was assessed previously for toxicity in adult minipigs. The endpoints included toxicokinetic parameters, in-life monitoring, clinical pathology, and histopathology. Additionally, the ontogeny of key nucleases involved in ASO metabolism and pharmacologic activity was investigated using quantitative polymerase chain reaction and nuclease activity assays. Similar clinical chemistry and toxicity findings were observed; however, differences in plasma and tissue exposures as well as pharmacologic activity were seen in the juvenile minipigs when compared with the adult data. The ontogeny study revealed a differential nuclease expression and activity, which could affect the metabolic pathway and pharmacologic effect of ASOs in different tissues and age groups. These data indicate that the juvenile Göttingen Minipig is a promising nonclinical model for safety assessment of ASOs intended to treat disease in the human pediatric population.
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Affiliation(s)
- Allan Valenzuela
- Comparative Perinatal Development, Department of Veterinary Sciences, University of Antwerp, 2610 Wilrijk, Belgium; (A.V.); (M.A.); (L.B.); (C.B.); (C.V.G.)
| | - Claire Tardiveau
- Charles River Laboratories France Safety Assessment SAS, 69210 Saint-Germain-Nuelles, France; (C.T.); (P.F.); (I.L.)
| | - Miriam Ayuso
- Comparative Perinatal Development, Department of Veterinary Sciences, University of Antwerp, 2610 Wilrijk, Belgium; (A.V.); (M.A.); (L.B.); (C.B.); (C.V.G.)
| | - Laura Buyssens
- Comparative Perinatal Development, Department of Veterinary Sciences, University of Antwerp, 2610 Wilrijk, Belgium; (A.V.); (M.A.); (L.B.); (C.B.); (C.V.G.)
| | - Chloe Bars
- Comparative Perinatal Development, Department of Veterinary Sciences, University of Antwerp, 2610 Wilrijk, Belgium; (A.V.); (M.A.); (L.B.); (C.B.); (C.V.G.)
| | - Chris Van Ginneken
- Comparative Perinatal Development, Department of Veterinary Sciences, University of Antwerp, 2610 Wilrijk, Belgium; (A.V.); (M.A.); (L.B.); (C.B.); (C.V.G.)
| | - Pierluigi Fant
- Charles River Laboratories France Safety Assessment SAS, 69210 Saint-Germain-Nuelles, France; (C.T.); (P.F.); (I.L.)
| | - Isabelle Leconte
- Charles River Laboratories France Safety Assessment SAS, 69210 Saint-Germain-Nuelles, France; (C.T.); (P.F.); (I.L.)
| | - Annamaria Braendli-Baiocco
- Roche Pharmaceutical Research and Early Development, F. Hoffmann-La-Roche, Ltd., 4070 Basel, Switzerland; (A.B.-B.); (N.P.); (G.S.); (Y.T.); (P.B.)
| | - Neil Parrott
- Roche Pharmaceutical Research and Early Development, F. Hoffmann-La-Roche, Ltd., 4070 Basel, Switzerland; (A.B.-B.); (N.P.); (G.S.); (Y.T.); (P.B.)
| | - Georg Schmitt
- Roche Pharmaceutical Research and Early Development, F. Hoffmann-La-Roche, Ltd., 4070 Basel, Switzerland; (A.B.-B.); (N.P.); (G.S.); (Y.T.); (P.B.)
| | - Yann Tessier
- Roche Pharmaceutical Research and Early Development, F. Hoffmann-La-Roche, Ltd., 4070 Basel, Switzerland; (A.B.-B.); (N.P.); (G.S.); (Y.T.); (P.B.)
| | - Paul Barrow
- Roche Pharmaceutical Research and Early Development, F. Hoffmann-La-Roche, Ltd., 4070 Basel, Switzerland; (A.B.-B.); (N.P.); (G.S.); (Y.T.); (P.B.)
| | - Steven Van Cruchten
- Comparative Perinatal Development, Department of Veterinary Sciences, University of Antwerp, 2610 Wilrijk, Belgium; (A.V.); (M.A.); (L.B.); (C.B.); (C.V.G.)
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Enhancing potency of siRNA targeting fusion genes by optimization outside of target sequence. Proc Natl Acad Sci U S A 2015; 112:E6597-605. [PMID: 26627251 DOI: 10.1073/pnas.1517039112] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Canonical siRNA design algorithms have become remarkably effective at predicting favorable binding regions within a target mRNA, but in some cases (e.g., a fusion junction site) region choice is restricted. In these instances, alternative approaches are necessary to obtain a highly potent silencing molecule. Here we focus on strategies for rational optimization of two siRNAs that target the junction sites of fusion oncogenes BCR-ABL and TMPRSS2-ERG. We demonstrate that modifying the termini of these siRNAs with a terminal G-U wobble pair or a carefully selected pair of terminal asymmetry-enhancing mismatches can result in an increase in potency at low doses. Importantly, we observed that improvements in silencing at the mRNA level do not necessarily translate to reductions in protein level and/or cell death. Decline in protein level is also heavily influenced by targeted protein half-life, and delivery vehicle toxicity can confound measures of cell death due to silencing. Therefore, for BCR-ABL, which has a long protein half-life that is difficult to overcome using siRNA, we also developed a nontoxic transfection vector: poly(lactic-coglycolic acid) nanoparticles that release siRNA over many days. We show that this system can achieve effective killing of leukemic cells. These findings provide insights into the implications of siRNA sequence for potency and suggest strategies for the design of more effective therapeutic siRNA molecules. Furthermore, this work points to the importance of integrating studies of siRNA design and delivery, while heeding and addressing potential limitations such as restricted targetable mRNA regions, long protein half-lives, and nonspecific toxicities.
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Angart P, Vocelle D, Chan C, Walton SP. Design of siRNA Therapeutics from the Molecular Scale. Pharmaceuticals (Basel) 2013; 6:440-68. [PMID: 23976875 PMCID: PMC3749788 DOI: 10.3390/ph6040440] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
While protein-based therapeutics is well-established in the market, development of nucleic acid therapeutics has lagged. Short interfering RNAs (siRNAs) represent an exciting new direction for the pharmaceutical industry. These small, chemically synthesized RNAs can knock down the expression of target genes through the use of a native eukaryotic pathway called RNA interference (RNAi). Though siRNAs are routinely used in research studies of eukaryotic biological processes, transitioning the technology to the clinic has proven challenging. Early efforts to design an siRNA therapeutic have demonstrated the difficulties in generating a highly-active siRNA with good specificity and a delivery vehicle that can protect the siRNA as it is transported to a specific tissue. In this review article, we discuss design considerations for siRNA therapeutics, identifying criteria for choosing therapeutic targets, producing highly-active siRNA sequences, and designing an optimized delivery vehicle. Taken together, these design considerations provide logical guidelines for generating novel siRNA therapeutics.
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Affiliation(s)
- Phillip Angart
- Department of Chemical Engineering and Materials Science, Michigan State University, 428 S. Shaw Lane, Room 2527, East Lansing, MI 48824, USA; (P.A.); (D.V.); (C.C.)
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Rapozzi V, Cogoi S, Xodo LE. Antisense locked nucleic acids efficiently suppress BCR/ABL and induce cell growth decline and apoptosis in leukemic cells. Mol Cancer Ther 2006; 5:1683-92. [PMID: 16891454 DOI: 10.1158/1535-7163.mct-06-0006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Chronic myeloid leukemia (CML) develops when a hematopoietic stem cell acquires the Philadelphia chromosome carrying the BCR/ABL fusion gene. This gives the transformed cells a proliferative advantage over normal hematopoietic cells. Silencing the BCR/ABL oncogene by treatment with specific drugs remains an important therapeutic goal. In this work, we used locked nucleic acid (LNA)-modified oligonucleotides to silence BCR/ABL and reduce CML cell proliferation, as these oligonucleotides are resistant to nucleases and exhibit an exceptional affinity for cognate RNA. The anti-BCR/ABL oligonucleotides were designed as LNA-DNA gapmers, consisting of end blocks of 3/4 LNA monomers and a central DNA stretch of 13/14 deoxyribonucleotides. The gapmers were complementary to the b2a2 and b3a2 mRNA junctions with which they form hybrid duplexes that have melting temperatures of 79 degrees C and 75 degrees C, respectively, in a 20 mmol/L NaCl-buffered (pH 7.4) solution. Like DNA, the designed LNA-DNA gapmers were capable of activating RNase H and promote cleavage of the target b2a2 and b3a2 BCR/ABL mRNAs. The treatment of CML cells with junction-specific antisense gapmers resulted in a strong and specific reduction of the levels of BCR/ABL transcripts ( approximately 20% of control) and protein p210(BCR/ABL) ( approximately 30% of control). Moreover, the antisense oligonucleotides suppressed cell growth up to 40% of control and induced apoptosis, as indicated by the increase of caspase-3/7 activity in the treated cells. Finally, the b2a2-specific antisense gapmer used in combination with STI571 (imatinib mesylate), a tyrosine kinase inhibitor of p210(BCR/ABL), produced an enhanced antiproliferative effect in KYO-1 cells, which compared with K562 cells are refractory to STI571. The data of this study support the application of BCR/ABL antisense LNA-DNA gapmers, used either alone or in combination with STI571, as potential antileukemic agents.
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MESH Headings
- Antineoplastic Combined Chemotherapy Protocols/chemistry
- Antineoplastic Combined Chemotherapy Protocols/therapeutic use
- Apoptosis/genetics
- Benzamides
- Cell Proliferation/drug effects
- Fusion Proteins, bcr-abl/analysis
- Fusion Proteins, bcr-abl/antagonists & inhibitors
- Fusion Proteins, bcr-abl/genetics
- Humans
- Imatinib Mesylate
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Oligonucleotides
- Oligonucleotides, Antisense/chemistry
- Oligonucleotides, Antisense/therapeutic use
- Piperazines/therapeutic use
- Protein Kinase Inhibitors/therapeutic use
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Pyrimidines/therapeutic use
- RNA, Messenger/antagonists & inhibitors
- Ribonuclease H/drug effects
- Transcription, Genetic/drug effects
- Tumor Cells, Cultured
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Affiliation(s)
- Valentina Rapozzi
- Department of Biomedical Sciences and Technologies, School of Medicine, P.le Kolbe 4, 33100 Udine, Italy
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Wu LX, Xu JH, Huang XW, Zhang KZ, Wen CX, Chen YZ. Down-regulation of p210(bcr/abl) by curcumin involves disrupting molecular chaperone functions of Hsp90. Acta Pharmacol Sin 2006; 27:694-9. [PMID: 16723087 DOI: 10.1111/j.1745-7254.2006.00326.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIM To investigate the effects of curcumin (Cur) on p210(bcr/abl) level in K562 cells, and the relationship between these effects and the molecular chaperone functions of heat shock protein 90 (Hsp90). METHODS Flow cytometry and Western blot were used to examine the abundance of p210(bcr/abl), Hsp90, p23, Hsp70, and p60(Hop) in K562 cells treated with Cur. Reverse transcription polymerase chain reaction (RT-PCR) was used to determine the bcr-abl mRNA level in K562 cells treated with Cur. After co-immunoprecipitation of p210(bcr/abl) and its molecular chaperones, the immunoprecipitate was then subjected to Western blot analysis with anti-Hsp90, anti-Hsp70, anti-p23, and anti- p60(Hop)mAb. RESULTS An exposure of K562 cells to Cur produced time-dependent down-regulation of p210(bcr/abl), the inhibition rate of p210(bcr/abl) in K562 cells determined by flow cytometry after treatment with Cur 27.2 micromol/L for 1 h, 6 h, 12 h and 24 h was 31.2%, 63.7%, 81.3% and 94.5%, respectively. In contrast, Cur had almost no influence on bcr-abl mRNA level. Treatment with Cur for 24 h reduced the association of p210(bcr/abl) with Hsp90/p23 complex, while increasing the association of p210(bcr/abl) with Hsp70/ p60(Hop) complex; however, the total protein abundance of Hsp90, p23, and p60(Hop) in K562 cells had no apparent change, while Hsp70 increased greatly. CONCLUSION Down-regulation of p210(bcr/abl) by Cur involves dissociating the binding of p210(bcr/abl) with Hsp90/p23 complex. In contrast, the association of p210(bcr/abl) with Hsp70/ p60(Hop) complex increased.
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Affiliation(s)
- Li-Xian Wu
- Institute of Clinical Pharmacology, Department of Pharmacology, Fujian Medical University, Fuzhou 350004, China
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6
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Withey JME, Harvey AJ, Crompton MR. RNA interference targeting of Bcr-Abl increases chronic myeloid leukemia cell killing by 17-allylamino-17-demethoxygeldanamycin. Leuk Res 2006; 30:553-60. [PMID: 16260034 DOI: 10.1016/j.leukres.2005.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Revised: 09/26/2005] [Accepted: 09/27/2005] [Indexed: 10/25/2022]
Abstract
17-Allylamino-17-demethoxygeldanamycin (17-AAG) induces degradation of Hsp90 client proteins, including Bcr-Abl, however, its clinical use as an anti-tumor agent may be limited by toxicity and modest efficacy. We reasoned that Bcr-Abl targeting by RNA interference (RNAi) might selectively increase the activity of 17-AAG against Bcr-Abl+ leukemia cells. 17-AAG in combination with targeting small interfering RNAs (siRNAs) reduced Bcr-Abl protein levels, triggered increases in markers of apoptosis and decreased cell viability more effectively than did control siRNA and 17-AAG together, or Bcr-Abl targeting siRNA alone. Combination targeting strategies such as this may therefore achieve enhanced therapeutic potency.
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MESH Headings
- Antineoplastic Combined Chemotherapy Protocols/pharmacology
- Benzoquinones/pharmacology
- Cell Death/drug effects
- Cell Line, Tumor
- Cell Proliferation/drug effects
- Cell Survival/drug effects
- Dose-Response Relationship, Drug
- Fusion Proteins, bcr-abl/antagonists & inhibitors
- Fusion Proteins, bcr-abl/genetics
- Fusion Proteins, bcr-abl/metabolism
- Gene Targeting/methods
- Humans
- K562 Cells
- Lactams, Macrocyclic/pharmacology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- RNA Interference
- RNA, Small Interfering/pharmacology
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Affiliation(s)
- Jane M E Withey
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
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7
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Tidd DM, Broughton CM, Clark RE. CpG oligodeoxynucleotide 5mer-induced apoptosis in MOLT-4 leukaemia cells does not require caspase 3 or new protein synthesis. Nucleic Acids Res 2003; 31:2297-304. [PMID: 12711674 PMCID: PMC154220 DOI: 10.1093/nar/gkg334] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2003] [Revised: 03/05/2003] [Accepted: 03/05/2003] [Indexed: 11/13/2022] Open
Abstract
We have established that CpG oligodeoxynucleotide 5mers, of sequence type CGNNN (N = A, G, C or T), rapidly induce apoptosis/cell cycle arrest in human leukaemia lines. The 5'-CpG is obligatory for these effects. Induction of apoptosis in MOLT-4 cells did not require new protein synthesis and was insensitive to the caspase 3 inhibitor, Ac-DEVD-CHO, although the latter abrogated DNA laddering, phosphatidylserine externalization and collapse of the mitochondrial transmembrane potential. A subline of MOLT-4 cells, MOLT-4CpGR, was selected for acquired resistance to CpG 5mers. Differences in gene expression between MOLT-4 and MOLT-4CpGR cells were identified following three independent reciprocal cDNA subtractions, consensus selection and virtual cloning through targeted display. Several known genes were implicated in the action of or resistance to CpG oligodeoxynucleotide 5mers. Their protein products listed below immediately suggest cell signalling pathways/processes worthy of further investigation in elucidating the mechanism of CpG 5mer activity: caspase 2, the transcription factors Atf4, Hic, HoxB3 and Rqcd1, the splicing factors Rbmx, Sfrs5 and Sfrs7, the DNA replication factors Mcm5 and Brd4, phosphoinositide-3-kinase, annexin A1, mucosa-associated lymphoid tissue lymphoma translocation 1 and three enzymes involved in protein ubiquitylation, Siah1, Gsa7 and Nin283.
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Affiliation(s)
- David M Tidd
- School of Biological Sciences, The University of Liverpool, Liverpool, UK.
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Hübinger G, Wehnes E, Xue L, Morris SW, Maurer U. Hammerhead ribozyme-mediated cleavage of the fusion transcript NPM-ALK associated with anaplastic large-cell lymphoma. Exp Hematol 2003; 31:226-33. [PMID: 12644020 DOI: 10.1016/s0301-472x(02)01084-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Approximately 60% of all anaplastic large-cell lymphomas (ALCL) contain a specific t(2;5)(p23;q35) chromosomal translocation leading to overexpression of NPM-ALK. As the chimeric tyrosine kinase is involved in tumorigenesis and pathogenesis of ALCL, we were interested to inhibit NPM-ALK expression using an exogenous and an endogenous ribozyme approach. METHODS We designed five anti-ALK hammerhead ribozymes that were targeted to cleave the ALK proportion of NPM-ALK. The ribozyme with the highest cleavage activity was used as a modified RNA/DNA chimera (RZ1*) for transient transfection and as a self-splicing ribozyme vector (pRZ1) for endogenous expression. Ribozyme performance was tested in 293 cells (cotransfected with NPM-ALK) and in the ALCL cell line Karpas 299 by transient and stable transfection and Western blotting. The half-life time of NPM-ALK was determined by pulse-chase experiments. RESULTS In vitro cleavage assays demonstrated different catalytic efficiencies depending on the targeted site of the substrate. Constant transfection of Karpas 299 cells with RZ1* for 96 hours did not lead to a significant reduction of NPM-ALK protein, presumably due to the long half-life of NPM-ALK (48 hours). In contrast, NPM-ALK protein expression was almost completely suppressed in transiently transfected 293 cells. Stable transfection of Karpas 299 cells with pRZ1 also resulted in significant reduction of NPM-ALK expression. CONCLUSION These results suggest that ribozymes targeted against NPM-ALK are able to inhibit expression of this oncogenic kinase efficiently and will be a useful tool to analyze its role in the pathophysiology of ALCL.
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Affiliation(s)
- Gabriele Hübinger
- Department of Internal Medicine III, University of Ulm, Ulm, Germany.
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Salesse S, Verfaillie CM. BCR/ABL: from molecular mechanisms of leukemia induction to treatment of chronic myelogenous leukemia. Oncogene 2002; 21:8547-59. [PMID: 12476301 DOI: 10.1038/sj.onc.1206082] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
MESH Headings
- Antineoplastic Agents/therapeutic use
- Fusion Proteins, bcr-abl
- Humans
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/physiopathology
- Protein-Tyrosine Kinases/genetics
- Protein-Tyrosine Kinases/metabolism
- Signal Transduction/drug effects
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Affiliation(s)
- Stephanie Salesse
- Stem Cell Institute, Cancer Center and Department of Medicine, University of Minnesota Cancer Center, Minneapolis, Minnesota, MN 55455, USA
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10
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Rapozzi V, Burm BEA, Cogoi S, van der Marel GA, van Boom JH, Quadrifoglio F, Xodo LE. Antiproliferative effect in chronic myeloid leukaemia cells by antisense peptide nucleic acids. Nucleic Acids Res 2002; 30:3712-21. [PMID: 12202756 PMCID: PMC137404 DOI: 10.1093/nar/gkf451] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Peptide nucleic acid (PNA) is a synthetic DNA analogue that is resistant to nucleases and proteases and binds with exceptional affinity to RNA. Because of these properties PNA has the potential to become a powerful therapeutic agent to be used in vivo. Until now, however, the use of PNA in vivo has not been much investigated. Here, we have attempted to reduce the expression of the bcr/abl oncogene in chronic myeloid leukaemia KYO-1 cells using a 13mer PNA sequence (asPNA) designed to hybridise to the b2a2 junction of bcr/abl mRNA. To enhance cellular uptake asPNA was covalently linked to the basic peptide VKRKKKP (NLS-asPNA). Moreover, to investigate the cellular uptake by confocal microscopy, both PNAs were linked by their N-terminus to fluorescein (FL). Studies of uptake, carried out at 4 and 37 degrees C on living KYO-1 cells stained with hexidium iodide, showed that both NLS-asPNA-FL and asPNA-FL were taken up by the cells, through a receptor-independent mechanism. The intracellular amount of NLS-asPNA-FL was about two to three times higher than that of asPNA-FL. Using a semi-quantitative RT- PCR technique we found that 10 micro M asPNA and NLS-asPNA reduced the level of b2a2 mRNA in KYO-1 cells to 20 +/- 5% and 60 +/- 10% of the control, respectively. Western blot analysis showed that asPNA promoted a significant inhibition of p210(BCR/ABL) protein: residual protein measured in cells exposed for 48 h to asPNA was approximately 35% of the control. Additionally, asPNA impaired cell growth to 50 +/- 5% of the control and inhibited completion of the cell cycle. In summary, these results demonstrate that a PNA 13mer is taken up by KYO-1 cells and is capable of producing a significant and specific down-regulation of the bcr/abl oncogene involved in leukaemogenesis.
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MESH Headings
- Antineoplastic Agents/metabolism
- Antineoplastic Agents/pharmacology
- Apoptosis/drug effects
- Base Sequence
- Cell Cycle/drug effects
- Cell Division/drug effects
- DNA, Antisense/chemistry
- DNA, Antisense/genetics
- DNA, Antisense/pharmacology
- Down-Regulation
- Flow Cytometry
- Fluorescein/chemistry
- Fusion Proteins, bcr-abl/genetics
- Humans
- K562 Cells
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology
- Microscopy, Confocal
- Molecular Sequence Data
- Nuclear Localization Signals/genetics
- Peptide Nucleic Acids/genetics
- RNA, Messenger/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Tumor Cells, Cultured/drug effects
- Tumor Cells, Cultured/metabolism
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Affiliation(s)
- Valentina Rapozzi
- Department of Biomedical Sciences and Technologies, School of Medicine, University of Udine, Piazzale Kolbe 4, 33100 Udine, Italy
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Hamelberg D, Williams LD, Wilson WD. Effect of a neutralized phosphate backbone on the minor groove of B-DNA: molecular dynamics simulation studies. Nucleic Acids Res 2002; 30:3615-23. [PMID: 12177304 PMCID: PMC134239 DOI: 10.1093/nar/gkf472] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Alternative models have been presented to provide explanations for the sequence-dependent variation of the DNA minor groove width. In a structural model groove narrowing in A-tracts results from direct, short-range interactions among DNA bases. In an electrostatic model, the narrow minor groove of A-tracts is proposed to respond to sequence-dependent localization of water and cations. Molecular dynamics simulations on partially methylphosphonate substituted helical chains of d(TATAGGCCTATA) and d(CGCGAATTCGCG) duplexes have been carried out to help evaluate the effects of neutralizing DNA phosphate groups on the minor groove width. The results show that the time-average minor groove width of the GGCC duplex becomes significantly more narrow on neutralizing the phosphate backbone with methylphosphonates. The minor groove of the AATT sequence is normally narrow and the methylphosphonate substitutions have a smaller but measurable affect on this sequence. These results and models provide a system that can be tested by experiment and they support the hypothesis that the electrostatic environment around the minor groove affects the groove width in a sequence-dependent dynamic and time-average manner.
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Affiliation(s)
- Donald Hamelberg
- Department of Chemistry, Georgia State University, 50 Decatur Street, Atlanta, GA 30303, USA
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12
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Sepe PS, Lahousse SA, Gemelli B, Chang H, Maeda T, Wands JR, de la Monte SM. Role of the aspartyl-asparaginyl-beta-hydroxylase gene in neuroblastoma cell motility. J Transl Med 2002; 82:881-91. [PMID: 12118090 DOI: 10.1097/01.lab.0000020406.91689.7f] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Aspartyl (asparaginyl) beta-hydroxylase (AAH) is overexpressed in various malignant neoplasms, and high levels of immunoreactivity mainly occur in infiltrating or metastasized tumors. In addition, AAH is abundantly expressed in normally invasive placental trophoblastic cells. These observations led to the hypothesis that AAH may have a role in motility and aggressive behavior of tumor cells. The present study demonstrates that AAH is overexpressed in primary human malignant neuroectodermal tumors, including medulloblastomas and neuroblastomas, and that AAH expression is at a low level or undetectable in the normal mature brain. In the Sy5y neuroblastoma cell line, endogenous expression of the approximately 86-kd AAH protein was demonstrated by Western blot analysis, and immunoreactivity predominantly localized to the cell surface by immunocytochemical staining and FACS analysis. Sy5y cells that were stably transfected with the human AAH cDNA had increased levels of proliferating cell nuclear antigen and Bcl-2, and reduced levels of p21/Waf1 and p16. In addition, increased AAH expression enhanced Sy5y cell motility, whereas antisense oligodeoxynucleotide inhibition of AAH significantly reduced Sy5y cell motility and increased the levels of p21/Waf1 and p16. The findings suggest that AAH overexpression contributes to the malignant phenotype of neuroectodermal tumor cells by increasing motility and enhancing proliferation, survival, and cell cycle progression. Because AAH expression is at a low level or undetectable in normal brain, the AAH gene may be a target for treating primitive neuroectodermal tumors.
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Affiliation(s)
- Paul S Sepe
- Department of Medicine, Rhode Island Hospital, Brown Medical School, Providence, Rhode Island 02903, USA
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Luger SM, O'Brien SG, Ratajczak J, Ratajczak MZ, Mick R, Stadtmauer EA, Nowell PC, Goldman JM, Gewirtz AM. Oligodeoxynucleotide-mediated inhibition of c-myb gene expression in autografted bone marrow: a pilot study. Blood 2002; 99:1150-8. [PMID: 11830460 DOI: 10.1182/blood.v99.4.1150] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Antisense oligodeoxynucleotide (ODN) drugs might be more effective if their delivery was optimized and they were targeted to short-lived proteins encoded by messenger RNA (mRNA) species with equally short half-lives. To test this hypothesis, an ODN targeted to the c-myb proto-oncogene was developed and used to purge marrow autografts administered to allograft-ineligible chronic myelogenous leukemia patients. CD34(+) marrow cells were purged with ODN for either 24 (n = 19) or 72 (n = 5) hours. After purging, Myb mRNA levels declined substantially in approximately 50% of patients. Analysis of bcr/abl expression in long-term culture-initiating cells suggested that purging had been accomplished at a primitive cell level in more than 50% of patients and was ODN dependent. Day-100 cytogenetics were evaluated in surviving patients who engrafted without infusion of unmanipulated "backup" marrow (n = 14). Whereas all patients were approximately 100% Philadelphia chromosome-positive (Ph(+)) before transplantation, 2 patients had complete cytogenetic remissions; 3 patients had fewer than 33% Ph(+) metaphases; and 8 remained 100% Ph(+). One patient's marrow yielded no metaphases, but fluorescent in situ hybridization evaluation approximately 18 months after transplantation revealed approximately 45% bcr/abl(+) cells, suggesting that 6 of 14 patients had originally obtained a major cytogenetic response. Conclusions regarding clinical efficacy of ODN marrow purging cannot be drawn from this small pilot study. Nevertheless, these results lead to the speculation that enhanced delivery of ODN, targeted to critical proteins of short half-life, might lead to the development of more effective nucleic acid drugs and the enhanced clinical utility of these compounds in the future.
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MESH Headings
- Adult
- Bone Marrow/drug effects
- Bone Marrow/metabolism
- Bone Marrow Purging/methods
- Bone Marrow Transplantation/methods
- Cytogenetic Analysis
- Female
- Fusion Proteins, bcr-abl/analysis
- Gene Expression/drug effects
- Genes, myb/drug effects
- Genes, myb/genetics
- Graft Survival
- Humans
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/diagnosis
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/therapy
- Male
- Middle Aged
- Oligodeoxyribonucleotides, Antisense/pharmacology
- Oligodeoxyribonucleotides, Antisense/therapeutic use
- Pilot Projects
- Proto-Oncogene Mas
- RNA, Messenger/antagonists & inhibitors
- RNA, Messenger/metabolism
- Transplantation, Autologous/methods
- Treatment Outcome
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Affiliation(s)
- Selina M Luger
- Division of Hematology/Oncology and the Stem Cell Biology/Therapeutics Program, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104, USA
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14
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Tidd DM, Giles RV, Broughton CM, Clark RE. Expression of c-myc is not critical for cell proliferation in established human leukemia lines. BMC Mol Biol 2001; 2:13. [PMID: 11734062 PMCID: PMC60647 DOI: 10.1186/1471-2199-2-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2001] [Accepted: 11/16/2001] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND A study was undertaken to resolve preliminary conflicting results on the proliferation of leukemia cells observed with different c-myc antisense oligonucleotides. RESULTS RNase H-active, chimeric methylphosphonodiester / phosphodiester antisense oligodeoxynucleotides targeting bases 1147-1166 of c-myc mRNA downregulated c-Myc protein and induced apoptosis and cell cycle arrest respectively in cultures of MOLT-4 and KYO1 human leukemia cells. In contrast, an RNase H-inactive, morpholino antisense oligonucleotide analogue 28-mer, simultaneously targeting the exon 2 splice acceptor site and initiation codon, reduced c-Myc protein to barely detectable levels but did not affect cell proliferation in these or other leukemia lines. The RNase H-active oligodeoxynucleotide 20-mers contained the phosphodiester linked motif CGTTG, which as an apoptosis inducing CpG oligodeoxynucleotide 5-mer of sequence type CGNNN (N = A, G, C, or T) had potent activity against MOLT-4 cells. The 5-mer mimicked the antiproliferative effects of the 20-mer in the absence of any antisense activity against c-myc mRNA, while the latter still reduced expression of c-myc in a subline of MOLT-4 cells that had been selected for resistance to CGTTA, but in this case the oligodeoxynucleotide failed to induce apoptosis or cell cycle arrest. CONCLUSIONS We conclude that the biological activity of the chimeric c-myc antisense 20-mers resulted from a non-antisense mechanism related to the CGTTG motif contained within the sequence, and not through downregulation of c-myc. Although the oncogene may have been implicated in the etiology of the original leukemias, expression of c-myc is apparently no longer required to sustain continuous cell proliferation in these culture lines.
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Affiliation(s)
- David M Tidd
- School of Biological Sciences, The University of Liverpool, Liverpool, UK
| | - Richard V Giles
- Department of Haematology, Royal Liverpool University Hospital, Liverpool, UK
| | | | - Richard E Clark
- Department of Haematology, Royal Liverpool University Hospital, Liverpool, UK
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15
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Marley SB, Davidson RJ, Lewis JL, Nguyen DX, Eades A, Parker S, Goldman JM, Gordon MY. Progenitor cells from patients with advanced phase chronic myeloid leukaemia respond to STI571 in vitro and in vivo. Leuk Res 2001; 25:997-1002. [PMID: 11597734 DOI: 10.1016/s0145-2126(01)00066-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
STI571 targets p210(BCR-ABL) in chronic myeloid leukaemia (CML). In vitro, STI571 reduces self-replication (replating ability) by chronic-phase CML CFU-GM. Here, we studied CFU-GM in advanced-phase (accelerated and blast crisis) CML. The numbers and self-replication of CFU-GM in advanced phase were greater than in the chronic phase. Self-replication by CFU-GM from advanced phase patients was reduced by STI571 or IFN alfa to the same extent as in the chronic phase. The reduced replating ability induced by STI571 correlated with that induced by IFN alpha (r=0.73). STI571 treatment in vivo also reduced replating ability and the numbers of CFU-GM/ml of blood.
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Affiliation(s)
- S B Marley
- Leukaemia Research Fund Centre for Adult Leukaemia, Department of Haematology, Imperial College School of Medicine, Hammersmith Campus, DuCane Road, W12 ONN, London, UK
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16
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Fennell DA, Cotter FE. A dynamical systems model to simulate the perturbation kinetics of gene expression by antisense oligonucleotides. J Theor Biol 2001; 209:103-12. [PMID: 11237574 DOI: 10.1006/jtbi.2000.2250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Antisense oligonucleotides owe their efficacy to an ability to induce RNase H-dependent suppression of RNA translation, for sufficient time to allow physiological proteolysis. The magnitude and time delay preceding the protein nadir concentration determine the extent and timing of maximum antisense oligonucleotide activity. Antisense oligonucleotide degradation underlies reversal of RNA downregulation. The kinetics of protein downregulation is therefore determined by the complex interaction of both ligand chemistry (nuclease stability, affinity and RNase H activation), and gene expression kinetics. Optimization of antisense oligonucleotide efficacy and experimental design requires understanding of these interactions. The kinetics of protein and RNA downregulation have therefore been simulated by analysing a two-compartment kinetic model incorporating RNase H-dependent transcript degradation. The system of nonlinear differential equations describing this model was solved numerically using Runge-Kutte integration. The timecourse solutions corresponding to the four state variables (RNA, protein, antisense/RNA heteroduplex and antisense oligonucleotide), were determined simultaneously. This allowed systematic in silico examination of the consequences of altering variables such as oligonucleotide concentration, affinity, and stability, or the scheduling of multiple transfections on RNA and protein perturbations. By providing a tool for examining antisense oligonucleotide action theoretically, this heuristic model should facilitate both the rational design and interpretation of antisense experiments.
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Affiliation(s)
- D A Fennell
- Department of Experimental Haematology, St Bartholomew's and The Royal London School of Medicine, Turner Street, London, E1 2AD, UK
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17
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Faria M, Spiller DG, Dubertret C, Nelson JS, White MR, Scherman D, Hélène C, Giovannangeli C. Phosphoramidate oligonucleotides as potent antisense molecules in cells and in vivo. Nat Biotechnol 2001; 19:40-4. [PMID: 11135550 DOI: 10.1038/83489] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Antisense oligonucleotides are designed to specifically hybridize to a target messenger RNA (mRNA) and interfere with the synthesis of the encoded protein. Uniformly modified oligonucleotides containing N3'-P5' phosphoramidate linkages exhibit (NP) extremely high-affinity binding to single-stranded RNA, do not induce RNase H activity, and are resistant to cellular nucleases. In the present work, we demonstrate that phosphoramidate oligonucleotides are effective at inhibiting gene expression at the mRNA level, by binding to their complementary target present in the 5'-untranslated region. Their mechanism of action was demonstrated by comparative analysis of three expression systems that differ only by the composition of the oligonucleotide target sequence (HIV-1 polypurine tract or PPT sequence) present just upstream from the AUG codon of the firefly luciferase reporter gene: the experiments have been done on isolated cells using oligonucleotide delivery mediated by cationic molecules or streptolysin O (SLO), and in vivo by oligonucleotide electrotransfer to skeletal muscle. In our experimental system phosphoramidate oligonucleotides act as potent and specific antisense agents by steric blocking of translation initiation; they may prove useful to modulate RNA metabolism while maintaining RNA integrity.
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Affiliation(s)
- M Faria
- Laboratoire de Biophysique, Muséum National d'Histoire Naturelle, INSERM U.201-CNRS UMR 8646, 43 rue Cuvier, 75005 Paris, France
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18
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Nellemann C, Abell K, Nørremølle A, Løkkegaard T, Naver B, Röpke C, Rygaard J, Sørensen SA, Hasholt L. Inhibition of Huntington synthesis by antisense oligodeoxynucleotides. Mol Cell Neurosci 2000; 16:313-23. [PMID: 11085870 DOI: 10.1006/mcne.2000.0872] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Huntington disease gone encodes the protein huntington, which is widely expressed during embryonic development and in mature tissues. In order to elucidate the physiological function of huntington, which so far is unknown, we intend to study the effect of antisense down-regulated huntington expression. We have found an inhibiting effect of a phosphorothioated oligodeoxynucleotide (PS-ODN) added to the culture medium of embryonic teratocarcinoma cells (NT2) and postmitotic neurons (NT2N neurons) differentiated from the NT2 cells. Specific inhibition of expression of endogenous huntington was achieved in NT2N neurons in the concentration range of 1-5 microM PS-ODN, whereas no inhibition was obtained in NT2 cells. We describe in detail the selection of the target sequence for the antisense oligo and the uptake, intracellular distribution, and stability of the antisense PS-ODN in the two cell types. Antisense down-regulation of huntington in this model of human neurons represents a suitable approach to study its normal function.
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Affiliation(s)
- C Nellemann
- Department of Medical Biochemistry and Genetics, Panum Institute, University of Copenhagen, Denmark
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19
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Novel oxime derivatives of radicicol induce erythroid differentiation associated with preferential G1 phase accumulation against chronic myelogenous leukemia cells through destabilization of Bcr-Abl with Hsp90 complex. Blood 2000. [DOI: 10.1182/blood.v96.6.2284] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Chronic myelogenous leukemia (CML) is a clonal disorder of a pluripotent hematopoietic stem cells characterized by a chimericbcr-abl gene giving rise to a p210Bcr-Ablprotein with dysregulated tyrosine kinase activity. Radicicol, a macrocyclic antifungal antibiotic, binds to the N-terminal of heat shock protein 90 (Hsp90) and destabilizes Hsp90-associated proteins such as Raf-1. This study investigated the effect of radicicol, novel oxime derivatives of radicicol (KF25706 and KF58333), and herbimycin A (HA), a benzoquinoid ansamycin antibiotic, on the growth and differentiation of human K562 CML cells. Although KF25706 and KF58333 induced the expression of glycophorin A in K562 cells, radicicol and HA caused erythroid differentiation transiently. Cell cycle analysis showed that G1 phase accumulation was observed in K562 cells treated with KF58333. KF58333 treatment depleted p210Bcr-Abl, Raf-1, and cellular tyrosine phosphorylated proteins in K562 cells, whereas radicicol and HA showed transient depletion of these proteins. KF58333 also down-regulated the level of cell cycle–dependent kinases 4 and 6 and up-regulated cell cycle–dependent kinase inhibitor p27Kip1protein without an effect on the level of Erk and Hsp90 proteins. Immunoprecipitation analysis showed that p210Bcr-Abl formed multiple complexes with Hsp90, some containing p23 and others Hsp70; KF58333 treatment dissociated p210Bcr-Abl from Hsp90/p23 chaperone complexes. Furthermore, KF58333 induced apoptosis in K562 cells and administration of KF58333 prolonged the survival time of SCID mice inoculated with K562 cells. These results suggest that KF58333 may have therapeutic potential for the treatment of CML that involves abnormal cellular proliferation induced by p210Bcr-Abl.
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20
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Novel oxime derivatives of radicicol induce erythroid differentiation associated with preferential G1 phase accumulation against chronic myelogenous leukemia cells through destabilization of Bcr-Abl with Hsp90 complex. Blood 2000. [DOI: 10.1182/blood.v96.6.2284.h8002284_2284_2291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chronic myelogenous leukemia (CML) is a clonal disorder of a pluripotent hematopoietic stem cells characterized by a chimericbcr-abl gene giving rise to a p210Bcr-Ablprotein with dysregulated tyrosine kinase activity. Radicicol, a macrocyclic antifungal antibiotic, binds to the N-terminal of heat shock protein 90 (Hsp90) and destabilizes Hsp90-associated proteins such as Raf-1. This study investigated the effect of radicicol, novel oxime derivatives of radicicol (KF25706 and KF58333), and herbimycin A (HA), a benzoquinoid ansamycin antibiotic, on the growth and differentiation of human K562 CML cells. Although KF25706 and KF58333 induced the expression of glycophorin A in K562 cells, radicicol and HA caused erythroid differentiation transiently. Cell cycle analysis showed that G1 phase accumulation was observed in K562 cells treated with KF58333. KF58333 treatment depleted p210Bcr-Abl, Raf-1, and cellular tyrosine phosphorylated proteins in K562 cells, whereas radicicol and HA showed transient depletion of these proteins. KF58333 also down-regulated the level of cell cycle–dependent kinases 4 and 6 and up-regulated cell cycle–dependent kinase inhibitor p27Kip1protein without an effect on the level of Erk and Hsp90 proteins. Immunoprecipitation analysis showed that p210Bcr-Abl formed multiple complexes with Hsp90, some containing p23 and others Hsp70; KF58333 treatment dissociated p210Bcr-Abl from Hsp90/p23 chaperone complexes. Furthermore, KF58333 induced apoptosis in K562 cells and administration of KF58333 prolonged the survival time of SCID mice inoculated with K562 cells. These results suggest that KF58333 may have therapeutic potential for the treatment of CML that involves abnormal cellular proliferation induced by p210Bcr-Abl.
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21
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Garcia-Chaumont C, Seksek O, Grzybowska J, Borowski E, Bolard J. Delivery systems for antisense oligonucleotides. Pharmacol Ther 2000; 87:255-77. [PMID: 11008003 DOI: 10.1016/s0163-7258(00)00062-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
In vitro, the efficacy of the antisense approach is strongly increased by systems delivering oligodeoxyribonucleotides (ODNs) to cells. Up to now, most of the developed vectors favor ODN entrance by a mechanism based on endocytosis. Such is the case for particulate systems, including liposomes (cationic or non-cationic), cationic polyelectrolytes, and delivery systems targeted to specific receptors. Under these conditions, endosomal compartments may represent a dead end for ODNs. Current research attempts to develop conditions for escaping from these compartments. A new class of vectors acts by passive permeabilization of the plasma membrane. It includes peptides, streptolysin O, and cationic derivatives of polyene antibiotics. In vivo, the interest of a delivery system, up to now, has appeared limited. Development of vectors insensitive to the presence of serum seems to be a prerequisite for future improvements.
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Affiliation(s)
- C Garcia-Chaumont
- LPBC, CNRS ESA 7033, Université Pierre et Marie Curie, case 138, 4, place Jussieu, 75252 05, Paris cedex, France
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22
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Stocks MR, Rabbitts TH. Masked antisense: a molecular configuration for discriminating similar RNA targets. EMBO Rep 2000; 1:59-64. [PMID: 11256626 PMCID: PMC1083679 DOI: 10.1093/embo-reports/kvd003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2000] [Revised: 04/03/2000] [Accepted: 04/17/2000] [Indexed: 11/15/2022] Open
Abstract
Antisense technology has great potential for the control of RNA expression, but there remain few successful applications of the technology. Expressed antisense RNA can effectively down-regulate expression of a gene over long periods, but cannot differentiate partly identical sequences, such as the mRNA of fusion genes or those with point mutants. We have designed a structured form of expressed antisense, which can discriminate between highly similar mRNA molecules. These 'masked' antisense RNAs have most of the antisense sequence sequestered within duplex elements, leaving a short single-stranded region to initiate binding to target RNA. After contacting the correct target, the structured RNA can unravel, releasing the masked antisense region to form a stable duplex with the mRNA. We demonstrate that suitable masked antisense RNA can discriminate between the two forms of BCR-ABL mRNA that result from the Philadelphia chromosomal translocations, as well as discriminating the normal BCR and ABL mRNA.
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Affiliation(s)
- M R Stocks
- MRC Laboratory of Molecular Biology, Cambridge, UK
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23
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Tidd DM, Spiller DG, Broughton CM, Norbury LC, Clark RE, Giles RV. Oligodeoxynucleotide 5mers containing a 5'-CpG induce apoptosis through a mitochondrial mechanism in T lymphocytic leukaemia cells. Nucleic Acids Res 2000; 28:2242-50. [PMID: 10871345 PMCID: PMC102630 DOI: 10.1093/nar/28.11.2242] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2000] [Revised: 04/07/2000] [Accepted: 04/07/2000] [Indexed: 01/25/2023] Open
Abstract
A chimeric methylphosphonodiester/phosphodiester 15mer oligodeoxynucleotide of randomly selected sequence was observed to rapidly induce apoptosis in MOLT-4 and Jurkat E6 T lymphocytic leukaemia cells following intracytoplasmic delivery. A series of further methylphosphonate substitutions and mutations and truncations of the oligodeoxynucleotide served to establish that the phosphodiester-linked sequence CGGTA present in the 15mer was responsible for this biological activity. End-protected CpG oligodeoxy-nucleotide 5mers of sequence type CGNNN exhibited a range of apoptosis-inducing potencies, with CGTTA being the most active. The latter was shown to significantly reduce the rate of RNA synthesis in MOLT-4 cells within 1 h; DNA laddering and redistribution of phosphatidylserine to the outer surface of the plasma membrane were marked by 160 min and mitochondrial transmembrane potential collapsed over roughly the same time scale. Pro-caspase 8 was reduced within 130 min and the proteolytically activated caspase 8 substrate Bid was also down by this time, implicating release of cytochrome c from mitochondria by the active 15 kDa fragment of Bid. Substantial proteolytic activation of pro-caspase 3 was relatively delayed. These findings support a mitochondrial amplification mechanism for apoptosis triggered by CpG 5mers.
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Affiliation(s)
- D M Tidd
- School of Biological Sciences and Department of Haematology, The University of Liverpool, UK.
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24
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Stenkamp DL, Frey RA, Prabhudesai SN, Raymond PA. Function for Hedgehog genes in zebrafish retinal development. Dev Biol 2000; 220:238-52. [PMID: 10753513 DOI: 10.1006/dbio.2000.9629] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The hedgehog (hh) genes encode secreted signaling proteins that have important developmental functions in vertebrates and invertebrates. In Drosophila, expression of hh coordinates retinal development by propagating a wave of photoreceptor differentiation across the eye primordium. Here we report that two vertebrate hh genes, sonic hedgehog (shh) and tiggy-winkle hedgehog (twhh), may perform similar functions in the developing zebrafish. Both shh and twhh are expressed in the embryonic zebrafish retinal pigmented epithelium (RPE), initially in a discrete ventral patch which then expands outward in advance of an expanding wave of photoreceptor recruitment in the subjacent neural retina. A gene encoding a receptor for the hedgehog protein, ptc-2, is expressed by retinal neuroepithelial cells. Injection of a cocktail of antisense (alphashh/alphatwhh) oligonucleotides reduces expression of both hh genes in the RPE and slows or arrests the progression of rod and cone photoreceptor differentiation. Zebrafish strains known to have mutations in Hh signaling pathway genes similarly exhibit retardation of photoreceptor differentiation. We propose that hedgehog genes may play a role in propagating photoreceptor differentiation across the developing eye of the zebrafish.
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Affiliation(s)
- D L Stenkamp
- Department of Biological Sciences, University of Idaho, Moscow, Idaho 83844-3051, USA
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25
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Giles RV, Spiller DG, Tidd DM. Chimeric oligodeoxynucleotide analogs: chemical synthesis, purification, and molecular and cellular biology protocols. Methods Enzymol 1999; 313:95-135. [PMID: 10595351 DOI: 10.1016/s0076-6879(00)13007-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- R V Giles
- Department of Haematology, University of Liverpool, Royal Liverpool University Hospital, United Kingdom
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26
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Giles RV, Spiller DG, Clark RE, Tidd DM. Identification of a good c-myc antisense oligodeoxynucleotide target site and the inactivity at this site of novel NCH triplet--targeting ribozymes. NUCLEOSIDES & NUCLEOTIDES 1999; 18:1935-44. [PMID: 10549146 DOI: 10.1080/07328319908044855] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
A region of c-myc mRNA was identified which permitted very efficient antisense effects to be achieved in living cells using chimeric methylphosphonate--phosphodiester antisense effectors. Novel inosine--containing ribozymes (which cleave after NCH triplets) were directed to an ACA triplet within this region and delivered into living cells. No ribozyme intracellular activity could be identified. Very low ribozyme function was also observed in in vitro assays using a 1700nt substrate RNA.
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Affiliation(s)
- R V Giles
- School of Biological Sciences, University of Liverpool
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27
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Giles RV, Spiller DG, Clark RE, Tidd DM. Antisense morpholino oligonucleotide analog induces missplicing of C-myc mRNA. ANTISENSE & NUCLEIC ACID DRUG DEVELOPMENT 1999; 9:213-20. [PMID: 10355827 DOI: 10.1089/oli.1.1999.9.213] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A 28-mer morpholino oligonucleotide analog was designed to hybridize to 8 bases of intron 1 and extend 2 bases beyond the translation initiation codon in exon 2 of the unspliced c-myc RNA transcript. Delivery of this compound into human chronic myeloid leukemia KYO1 cells, by streptolysin O permeabilization, resulted in almost total ablation of the 65 kDa c-MYC protein expression for at least 24 hours after treatment. An unexpected band with SDS-PAGE electrophoretic mobility indicating a protein of about 47 kDa was apparent on the 24-hour western blots that were developed using antibodies that recognize MYC protein C terminal epitopes. No inhibition of the approximately 2400 nt c-myc mRNA expression was observed by northern hybridization, a result of the inability of morpholino analogs to direct the activity of ribonuclease H. In fact, high molecular weight c-myc RNA species were found to have accumulated in antisense-treated KYO1 cells. Control sense and scrambled antisense morpholino analogs did not inhibit MYC protein expression or induce the appearance of the anomalous RNA and protein bands. Molecular analyses by RT-PCR and sequencing revealed that the morpholino antisense effector had (1) inhibited splicing of the c-myc pre-mRNA, (2) induced missplicing of the pre-mRNA, and (3) inhibited translation of normal spliced c-myc mRNA. Identical results were obtained with acute promyelocytic leukemia, acute lymphoblastic leukemia, and histiocytic lymphoma cell lines.
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Affiliation(s)
- R V Giles
- School of Biological Sciences, University of Liverpool, U.K
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