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Abstract
Radiation therapy methods have evolved remarkably in recent years which have resulted in more effective local tumor control with negligible toxicity of surrounding normal tissues. However, local recurrence and distant metastasis often occur following radiation therapy mostly due to the development of radioresistance through the deregulation of the cell cycle, apoptosis, and inhibition of DNA damage repair mechanisms. Over the last decade, extensive progress in radiotherapy and gene therapy combinatorial approaches has been achieved to overcome resistance of tumor cells to radiation. In this review, we summarize the results from experimental cancer therapy studies on the combination of radiation therapy and gene therapy.
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Dasgupta T, Haas-Kogan DA, Yang X, Olow A, Yang DX, Gragg A, Orloff LA, Yom SS. Genotype-dependent cooperation of ionizing radiation with BRAF inhibition in BRAF V600E-mutated carcinomas. Invest New Drugs 2013; 31:1136-41. [PMID: 23354848 DOI: 10.1007/s10637-013-9928-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 01/07/2013] [Indexed: 01/09/2023]
Abstract
BACKGROUND A substantial proportion of solid tumors carry the BRAF V600E mutation, which causes activation of the MEK/MAPK pathway and is a poor prognostic indicator. Patients with locally advanced human cancers are often treated with external beam radiation therapy. Given the association of Raf overactivation with radioresistance, we hypothesized that, in BRAF V600E-mutated carcinomas, there would be combinatorial activity between radiation and PLX4720, a specific BRAF V600E-inhibitor. METHODS Two BRAF V600E-mutated cancer cell lines and one BRAF-V600E wildtype (WT) cancer cell line were obtained. We performed cell viability assays and clonogenic assays using combinations of radiation and PLX4720. We assessed MEK and MAPK phosphorylation at different PLX4720 concentrations with western blotting, and cell cycle progression was evaluated by flow cytometry. RESULTS Our results show combinatorial, additive activity between radiation and PLX4720 in BRAF V600E-mutated cell lines, but not in the BRAF WT line. In BRAF V600E-mutated cells, there was a PLX4720 concentration-dependent decrease in MEK and MAPK phosphorylation. In cells with BRAF V600E mutations, PLX4720 caused cell cycle arrest at G1, and, when combined with radiation, caused a combined G1 and G2 cell cycle arrest; this pattern of cell cycle effects was not seen in the BRAF WT cell line. CONCLUSIONS These data suggest additive, combinatorial activity between radiation and PLX4720 in cancers carrying BRAF V600E mutations. Our data has potential for translation into the multimodality treatment of BRAF V600E-mutated cancers.
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Affiliation(s)
- Tina Dasgupta
- Department of Radiation Oncology, University of California, San Francisco, 1600 Divisadero Street, Suite H-1031, San Francisco, CA, 94143-1708, USA
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Spugnini EP, Biroccio A, De Mori R, Scarsella M, D'Angelo C, Baldi A, Leonetti C. Electroporation increases antitumoral efficacy of the bcl-2 antisense G3139 and chemotherapy in a human melanoma xenograft. J Transl Med 2011; 9:125. [PMID: 21798045 PMCID: PMC3163203 DOI: 10.1186/1479-5876-9-125] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 07/28/2011] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Nucleic acids designed to modulate the expression of target proteins remain a promising therapeutic strategy in several diseases, including cancer. However, clinical success is limited by the lack of efficient intracellular delivery. In this study we evaluated whether electroporation could increase the delivery of antisense oligodeoxynucleotides against bcl-2 (G3139) as well as the efficacy of combination chemotherapy in human melanoma xenografts. METHODS Melanoma-bearing nude mice were treated i.v. with G3139 and/or cisplatin (DDP) followed by the application of trains of electric pulses to tumors. Western blot, immunohistochemistry and real-time PCR were performed to analyze protein and mRNA expression. The effect of electroporation on muscles was determined by histology, while tumor apoptosis and the proliferation index were analyzed by immunohistochemistry. Antisense oligodeoxynucleotides tumor accumulation was measured by FACS and confocal microscopy. RESULTS The G3139/Electroporation combined therapy produced a significant inhibition of tumor growth (TWI, more than 50%) accompanied by a marked tumor re-growth delay (TRD, about 20 days). The efficacy of this treatment was due to the higher G3139 uptake in tumor cells which led to a marked down-regulation of bcl-2 protein expression. Moreover, the G3139/EP combination treatment resulted in an enhanced apoptotic index and a decreased proliferation rate of tumors. Finally, an increased tumor response was observed after treatment with the triple combination G3139/DDP/EP, showing a TWI of about 75% and TRD of 30 days. CONCLUSIONS These results demonstrate that electroporation is an effective strategy to improve the delivery of antisense oligodeoxynucleotides within tumor cells in vivo and it may be instrumental in optimizing the response of melanoma to chemotherapy. The high response rate observed in this study suggest to apply this strategy for the treatment of melanoma patients.
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Affiliation(s)
- Enrico P Spugnini
- S.A.F.U. Department, Regina Elena Cancer Institute, (Via delle Messi d'Oro 156), Rome (00158), Italy.
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Zhang C, Newsome JT, Mewani R, Pei J, Gokhale PC, Kasid UN. Systemic delivery and pre-clinical evaluation of nanoparticles containing antisense oligonucleotides and siRNAs. Methods Mol Biol 2009; 480:65-83. [PMID: 19085118 DOI: 10.1007/978-1-59745-429-2_5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
By virtue of their potential to selectively silence oncogenic molecules in cancer cells, antisense oligonucleotides (ASO) and small interfering RNAs (siRNAs) are powerful tools for development of tailored anti-cancer drugs. The clinical benefit of ASO/siRNA therapeutic is, however, hampered due to poor pharmacokinetics and biodistribution, and suboptimal suppression of the target in tumor tissues. Raf-1 protein serine/threonine kinase is a druggable signaling molecule in cancer therapy. Our laboratory has developed cationic liposomes for systemic delivery of raf ASO (LErafAON) and raf siRNA (LErafsiRNA) to human tumor xenografts grown in athymic mice. LErafAON is also the first ASO containing liposomal drug tested in humans. In this article, we primarily focus on a modified formulation of systemically delivered cationic liposomes containing raf antisense oligonucleotide (md-LErafAON). The cationic liposomes were prepared using dimyristoyl 1,2-diacyl-3-trimethylammonium-propane (DMTAP), phosphatidylcholine (PC), and cholesterol (CHOL). The toxicology, pharmacokinetics, biodistribution, target selectivity, and anti-tumor efficacy studies of md-LErafAON were conducted in mice. We demonstrate that md-LErafAON is the next generation of systemically delivered and well-tolerated antisense therapeutic suitable for clinical evaluation.
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Affiliation(s)
- Chuanbo Zhang
- Departments of Radiation Medicine and Biochemistry, Molecular and Cellular Biology, Georgetown University Medical Center, Washington D.C. 20057, USA
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Mansoor M, Melendez AJ. Advances in antisense oligonucleotide development for target identification, validation, and as novel therapeutics. GENE REGULATION AND SYSTEMS BIOLOGY 2008; 2:275-95. [PMID: 19787090 PMCID: PMC2733095 DOI: 10.4137/grsb.s418] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Antisense oligonucleotides (As-ODNs) are single stranded, synthetically prepared strands of deoxynucleotide sequences, usually 18–21 nucleotides in length, complementary to the mRNA sequence of the target gene. As-ODNs are able to selectively bind cognate mRNA sequences by sequence-specific hybridization. This results in cleavage or disablement of the mRNA and, thus, inhibits the expression of the target gene. The specificity of the As approach is based on the probability that, in the human genome, any sequence longer than a minimal number of nucleotides (nt), 13 for RNA and 17 for DNA, normally occurs only once. The potential applications of As-ODNs are numerous because mRNA is ubiquitous and is more accessible to manipulation than DNA. With the publication of the human genome sequence, it has become theoretically possible to inhibit mRNA of almost any gene by As-ODNs, in order to get a better understanding of gene function, investigate its role in disease pathology and to study novel therapeutic targets for the diseases caused by dysregulated gene expression. The conceptual simplicity, the availability of gene sequence information from the human genome, the inexpensive availability of synthetic oligonucleotides and the possibility of rational drug design makes As-ODNs powerful tools for target identification, validation and therapeutic intervention. In this review we discuss the latest developments in antisense oligonucleotide design, delivery, pharmacokinetics and potential side effects, as well as its uses in target identification and validation, and finally focus on the current developments of antisense oligonucleotides in therapeutic intervention in various diseases.
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Affiliation(s)
- Moizza Mansoor
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Nakajima T. Positive and negative regulation of radiation-induced apoptosis by protein kinase C. JOURNAL OF RADIATION RESEARCH 2008; 49:1-8. [PMID: 17785935 DOI: 10.1269/jrr.07053] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Indicators such as clonogenic survival, transformation, and chromosomal aberrations are used to evaluate the effects of radiation on cells. Apoptosis, another such indicator, is a mode of cell death, and radiation-induced apoptosis contributes to eliminating damaged cells and preventing malformation and carcinogenesis. Understanding radiation-induced apoptosis will assist in radiotherapy for cancer and treatment of patients in accidental radiation exposure. Protein kinase C (PKC) is a serine/threonine kinase that is related to cell proliferation, differentiation, metabolism, and apoptosis, and has many roles in the radiation-induced cellular responses involving apoptosis. This review describes the functions of PKC, including its relationship with other signaling networks and oxidative stress in the regulation of radiation-induced apoptosis. Such information might provide clues for evaluating the effects of radiation and for identifying clinical applications.
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Affiliation(s)
- Tetsuo Nakajima
- Radiation Effect Mechanisms Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, Japan.
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Abstract
Over the past 5 years, the Raf kinase family has emerged as a promising target for protein-directed cancer therapy development. The goal of this review is to first provide a concise summary of the data validating Raf proteins as high-interest therapeutic targets. The authors then outline the mode of action of Raf kinases, emphasizing how Raf activities and protein interactions suggest specific approaches to inhibiting Raf. The authors then summarize the set of drugs, antisense reagents and antibodies available or in development for therapeutically targeting Raf or Raf-related proteins, as well as existing strategies combining these and other therapeutic agents. Finally, the authors discuss recent results from systems biology analyses that have the potential to increasingly guide the intelligent selection of combination therapies involving Raf-targeting agents and other therapeutics.
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de Jong S, Chikh G, Sekirov L, Raney S, Semple S, Klimuk S, Yuan N, Hope M, Cullis P, Tam Y. Encapsulation in liposomal nanoparticles enhances the immunostimulatory, adjuvant and anti-tumor activity of subcutaneously administered CpG ODN. Cancer Immunol Immunother 2007; 56:1251-64. [PMID: 17242927 PMCID: PMC11030982 DOI: 10.1007/s00262-006-0276-x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Accepted: 12/15/2006] [Indexed: 12/19/2022]
Abstract
Immunostimulatory oligodeoxynucleotides (ODN) containing cytosine-guanine (CpG) motifs are powerful stimulators of innate as well as adaptive immune responses, exerting their activity through triggering of the Toll-like receptor 9. We have previously shown that encapsulation in liposomal nanoparticles (LN) enhances the immunostimulatory activity of CpG ODN (LN-CpG ODN) (Mui et al. in J Pharmacol Exp Ther 298:1185, 2001). In this work we investigate the effect of encapsulation on the immunopotency of subcutaneously (s.c.) administered CpG ODN with regard to activation of innate immune cells as well as its ability to act as a vaccine adjuvant with tumor-associated antigens (TAAs) to induce antigen (Ag)-specific, adaptive responses and anti-tumor activity in murine models. It is shown that encapsulation specifically targets CpG ODN for uptake by immune cells. This may provide the basis, at least in part, for the significantly enhanced immunostimulatory activity of LN-CpG ODN, inducing potent innate (as judged by immune cell activation and plasma cytokine/chemokine levels) and adaptive, Ag-specific (as judged by MHC tetramer positive T lymphocytes, IFN-gamma secretion and cytotoxicity) immune responses. Finally, in efficacy studies, it is shown that liposomal encapsulation enhances the ability of CpG ODN to adjuvanate adaptive immune responses against co-administered TAAs after s.c. immunization, inducing effective anti-tumor activity against both model and syngeneic tumor Ags in murine tumor models of thymoma and melanoma.
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MESH Headings
- Adjuvants, Immunologic/administration & dosage
- Adjuvants, Immunologic/pharmacokinetics
- Adjuvants, Immunologic/pharmacology
- Animals
- Antineoplastic Agents/administration & dosage
- Antineoplastic Agents/pharmacokinetics
- Antineoplastic Agents/pharmacology
- CD8-Positive T-Lymphocytes/drug effects
- CD8-Positive T-Lymphocytes/immunology
- Cancer Vaccines/therapeutic use
- Chemokine CCL2/blood
- Drug Compounding
- Drug Screening Assays, Antitumor
- Female
- Fluorescent Dyes/analysis
- Injections, Subcutaneous
- Interferon-gamma/blood
- Interleukin-10/blood
- Interleukin-6/blood
- Intramolecular Oxidoreductases/immunology
- Liposomes/administration & dosage
- Liposomes/pharmacokinetics
- Lung Neoplasms/secondary
- Lung Neoplasms/therapy
- Lymphocyte Activation/drug effects
- Melanoma, Experimental/immunology
- Melanoma, Experimental/secondary
- Melanoma, Experimental/therapy
- Mice
- Mice, Inbred C57BL
- Mice, Inbred ICR
- Nanoparticles/administration & dosage
- Oligodeoxyribonucleotides/administration & dosage
- Oligodeoxyribonucleotides/pharmacokinetics
- Oligodeoxyribonucleotides/pharmacology
- Ovalbumin/immunology
- Thymoma/immunology
- Thymoma/secondary
- Thymoma/therapy
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Affiliation(s)
- Susan de Jong
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC Canada
| | - Ghania Chikh
- Inex Pharmaceuticals Corporation, Burnaby, BC Canada
| | - Laura Sekirov
- Inex Pharmaceuticals Corporation, Burnaby, BC Canada
| | - Sam Raney
- Inex Pharmaceuticals Corporation, Burnaby, BC Canada
| | - Sean Semple
- Inex Pharmaceuticals Corporation, Burnaby, BC Canada
| | - Sandra Klimuk
- Inex Pharmaceuticals Corporation, Burnaby, BC Canada
| | - Ning Yuan
- Inex Pharmaceuticals Corporation, Burnaby, BC Canada
| | - Micheal Hope
- Inex Pharmaceuticals Corporation, Burnaby, BC Canada
| | - Pieter Cullis
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC Canada
| | - Ying Tam
- Inex Pharmaceuticals Corporation, Burnaby, BC Canada
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9
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Affiliation(s)
- Kathryn Graham
- The Beatson Institute for Cancer Research, Garscube Estate, Glasgow, UK
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10
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Dass CR, Choong PFM. Selective gene delivery for cancer therapy using cationic liposomes: in vivo proof of applicability. J Control Release 2006; 113:155-63. [PMID: 16764960 DOI: 10.1016/j.jconrel.2006.04.009] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Revised: 04/06/2006] [Accepted: 04/06/2006] [Indexed: 10/24/2022]
Abstract
Targeted gene therapy is essential if cancer treatment is to become a reality with this form of therapy. In the past few years, cationic liposomes, discovered 2 decades ago, and at present, the most commonly used class of transfection reagents, have been tested in various clinical trials for diseases not restricted to cancer. They have been shown to be selective for tumour vascular endothelial cells raising hopes for antiangiogenic and antivascular therapies. They are also capable of being selectively delivered to the lungs and liver when administered intravenously. These vesicles are also being targeted to the tumour in various parts of the body by using advanced liposomal systems such as antibody-antigen and ligand-receptor combinations. This review looks at the state of play in this rapidly growing field.
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Affiliation(s)
- Crispin R Dass
- Department of Orthopaedics, University of Melbourne, St. Vincent's Hospital Melbourne, P.O. Box 2900, Fitzroy 3065, Australia.
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11
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Cao C, Shinohara ET, Li H, Niermann KJ, Kim KW, Sekhar KR, Gleave M, Freeman M, Lu B. Clusterin as a therapeutic target for radiation sensitization in a lung cancer model. Int J Radiat Oncol Biol Phys 2005; 63:1228-36. [PMID: 16253777 DOI: 10.1016/j.ijrobp.2005.07.956] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2005] [Revised: 06/28/2005] [Accepted: 07/01/2005] [Indexed: 01/13/2023]
Abstract
PURPOSE Clusterin plays important roles in cell survival and death. Inactivation of clusterin enhances the therapeutic efficacy of chemotherapy in lung cancer models. The purpose of this study was to determine whether inhibition of clusterin by an antisense-based investigative drug enhances radiation sensitization in a lung cancer model. METHODS AND MATERIALS Cells were transfected with an antisense oligonucleotide (ASO) against clusterin (OGX-011). Apoptosis was determined by 7-aminoactinomycin D staining. Cell survival was examined by 3-(4, 5-methylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide (MTT) and clonogenic assay. Xenograft model was used to demonstrate tumor growth and tumor blood flow. RESULTS OGX-011 specifically attenuated the expression of secreted clusterin (prosurvival), with no apparent effect on the expression of nuclear clusterin (proapoptotic). Apoptosis was significantly increased when H460 lung cancer cells were treated with OGX-011 plus radiation. Inhibition of clusterin followed by radiation greatly decreased cell survival. H460 xenografts that were treated with OGX-011 plus radiotherapy demonstrated growth delay beyond 17 days. Doppler studies showed that tumor blood flow was compromised when mice bearing H460 xenografts were treated with OGX-011 and radiation. CONCLUSION A combination of radiotherapy and OGX-011 improved control of tumor growth and vascular regression in the H460 lung cancer model.
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Affiliation(s)
- Carolyn Cao
- Department of Radiation Oncology, Vanderbilt Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232-5671, USA
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12
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Beeram M, Patnaik A, Rowinsky EK. Raf: A Strategic Target for Therapeutic Development Against Cancer. J Clin Oncol 2005; 23:6771-90. [PMID: 16170185 DOI: 10.1200/jco.2005.08.036] [Citation(s) in RCA: 199] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The mitogen-activated protein kinase (MAPK) signaling pathway plays a critical role in transmitting proliferative signals generated by cell surface receptors and cytoplasmic signaling elements to the nucleus. Several important signaling elements of the MAPK pathway, particularly Ras and Raf, are encoded by oncogenes, and as such, their structures and functions can be modified, rendering them constitutively active. Because the MAPK pathway is dysregulated in a notable proportion of human malignancies, many of its aberrant and critical components represent strategic targets for therapeutic development against cancer. Raf, which is an essential serine/threonine kinase constituent of the MAPK pathway and a downstream effector of the central signal transduction mediator Ras, is activated in a wide range of human malignancies by aberrant signaling upstream of the protein (eg, growth factor receptors and mutant Ras) and activating mutations of the protein itself, both of which confer a proliferative advantage. Three isoforms of Raf have been identified, and therapeutics targeting Raf, including small-molecule inhibitors and antisense oligodeoxyribonucleotides (ASON), are undergoing clinical evaluation. The outcomes of these investigations may have far-reaching implications in the management of many types of human cancer. This review outlines the structure and diverse functions of Raf, the rationale for targeting Raf as a therapeutic strategy against cancer, and the present status of various therapeutic approaches including ASONs and small molecules, particularly sorafenib (BAY 43-9006).
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Affiliation(s)
- Muralidhar Beeram
- University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
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13
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Pei J, Zhang C, Gokhale PC, Rahman A, Dritschilo A, Ahmad I, Kasid UN. Combination with liposome-entrapped, ends-modified raf antisense oligonucleotide (LErafAON) improves the anti-tumor efficacies of cisplatin, epirubicin, mitoxantrone, docetaxel and gemcitabine. Anticancer Drugs 2004; 15:243-53. [PMID: 15014358 DOI: 10.1097/00001813-200403000-00009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Raf-1 protein serine/threonine kinase plays an important role in cell proliferation and cell survival. We have previously described a novel cationic liposome-entrapped formulation of raf antisense oligodeoxyribonucleotide (LErafAON) and its use as a radiosensitizer. The aim of this study was to examine the effect of combination of LErafAON and a chemotherapeutic agent on growth of human prostate (PC-3) and pancreatic tumor xenografts in athymic mice (Aspc-1 and Colo 357). In PC-3 tumor-bearing mice, administration of a combination of LErafAON (i.v., 25 mg/kg/dose, x10/16) and cisplatin (i.v., 11.0 mg/kg/dose, x3), epirubicin (EPI) (i.v., 9.0 mg/kg/dose, x3) or mitoxantrone (MTO) (i.v., 2.5 mg/kg/dose, x3) led to enhanced tumor growth inhibition as compared with single agents (LErafAON+cisplatin versus cisplatin, p<0.0002, n=8; LErafAON+EPI versus EPI, p<0.0001, n=6; LErafAON+MTO versus MTO, p<0.05, n=5). In prostate or pancreatic tumor-bearing mice, combination of LErafAON (i.v., 25 mg/kg/dose, x10/13) with docetaxel (Taxotere) (i.v., 5, 7.5 or 10 mg/kg/dose, x2/4) led to tumor regression or enhanced growth inhibition as compared with single agents (PC-3: LErafAON+Taxotere versus Taxotere, p<0.02, n=7; Aspc-1: LErafAON+Taxotere versus Taxotere, p<0.03, n=5; Colo 357: LErafAON+Taxotere versus Taxotere, p<0.04, n=7). Combination of LErafAON (i.v., 25 mg/kg/dose, x10/13) with gemcitabine (i.v., 75 mg/kg/dose, x4/6) also caused a significant tumor growth inhibition in the two pancreatic carcinoma models studied (Aspc-1: LErafAON+gemcitabine versus gemcitabine, p<0.0001, n=7; Colo 357: LErafAON+gemcitabine versus gemcitabine, p<0.002, n =5). LErafAON treatment (i.v., 25 mg/kg/dose, x10) caused inhibition of Raf-1 protein expression in these tumor tissues (around 25-60%, n=4-7). Interestingly, Taxotere treatment per se also led to decreased steady state level of Raf-1 protein in PC-3 and Aspc-1 tumor tissues (i.v., 10 mg/kg/dose, x1 or 7.5 mg/kg/dose, x2; around 25-80%, n=2/6). Present studies demonstrate enhanced tumor growth inhibition or regression in response to a combination of a chemotherapeutic drug and LErafAON. These data provide a proof-of-principle for the clinical use of LErafAON in combination with chemotherapy for cancer treatment.
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Affiliation(s)
- Jin Pei
- Department of Radiation Medicine, Lombardi Cancer Center, Georgetown University Medical Center, Washington, DC 20007, USA
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14
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Stuart DD, Semple SC, Allen TM. High efficiency entrapment of antisense oligonucleotides in liposomes. Methods Enzymol 2004; 387:171-88. [PMID: 15172164 DOI: 10.1016/s0076-6879(04)87011-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- Darrin D Stuart
- Chiron Corporation, Cancer Pharmacology, Emeryville, CA 94608, USA
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15
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Valerón PF, Aznar-Benitah S, Lacal JC. Signal transduction and apoptosis pathways as therapeutic targets. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2004; 36:307-23. [PMID: 15171618 DOI: 10.1007/978-3-540-74264-7_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Affiliation(s)
- P F Valerón
- Instituto de Investigaciones Biomédicas, CSIC, Arturo Duperier 4, 28029 Madrid, Spain
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16
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McKenna WG, Muschel RJ, Gupta AK, Hahn SM, Bernhard EJ. The RAS signal transduction pathway and its role in radiation sensitivity. Oncogene 2003; 22:5866-75. [PMID: 12947393 DOI: 10.1038/sj.onc.1206699] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
RAS has been shown to increase radiation resistance. Upstream and downstream pathways from RAS could thus be targets for manipulation of radiosensitivity. EGFR expression and AKT phosphorylation are also associated with the response to radiation. A retrospective study evaluating EGFR and AKT in patients treated with multimodality therapy found a significant association between P-AKT and treatment failure. Moreover, these data are strengthened by in vitro studies showing that inhibition of EGFR, RAS, PI3K, and AKT radiosensitized cancer cell lines. We have previously shown that PI3K is a mediator of RAS-induced radiation resistance. We now suggest that EGFR, which is upstream of PI3K, may also mediate resistance through a common pathway. In addition to EGFR and RAS, PTEN can also regulate the PI3K pathway. Identifying a common signal for EGFR, RAS, or PTEN that results in radiation resistance may uncover targets for developing molecular-based radiosensitization protocols for tumors resistant to radiation and thus improve local control.
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Affiliation(s)
- W Gillies McKenna
- Departments of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19103, USA.
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Abstract
The RAF-1 serine-threonine kinase plays a central role in signal transduction pathways involved in cell survival and proliferation. The concept of RAF-1-targeted disruption of cell signaling for therapeutic purposes was first advanced in 1989 with the demonstration of tumor growth inhibition in athymic mice and radiosensitization of human squamous carcinoma cells transfected with a vector expressing antisense cDNA. However, the clinical application of antisense strategies has awaited the development of improved antisense oligonucleotide technologies and drug delivery methods. Nuclease-resistant phosphorothioated antisense oligonucleotides have been the focus of pharmaceutical industry attention. In vivo delivery of nuclease-sensitive, natural backbone/phosphodiester oligonucleotides has remained a formidable challenge. Liposomal encapsulation of antisense oligonucleotides protects them from degradation and enhances drug delivery. Here, we review the importance of targeting RAF-1 signaling in cancer therapy and the preclinical and clinical experiences with a liposomal formulation of a nuclease-sensitive, ends-modified antisense RAF oligonucleotide.
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Affiliation(s)
- Usha Kasid
- Department of Radiation Medicine, Lombardi Cancer Center, Georgetown University Medical Center, Washington, DC 20007, USA
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18
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Abstract
Within the last 15 years, multiple new signal transduction pathways within cells have been discovered. Many of these pathways belong to what is now termed 'the mitogen-activated protein kinase (MAPK) superfamily.' These pathways have been linked to the growth factor-mediated regulation of diverse cellular events such as proliferation, senescence, differentiation and apoptosis. Based on currently available data, exposure of cells to ionizing radiation and a variety of other toxic stresses induces simultaneous compensatory activation of multiple MAPK pathways. These signals play critical roles in controlling cell survival and repopulation effects following irradiation, in a cell-type-dependent manner. Some of the signaling pathways activated following radiation exposure are those normally activated by mitogens, such as the 'classical' MAPK (also known as the ERK) pathway. Other MAPK pathways activated by radiation include those downstream of death receptors and procaspases, and DNA-damage signals, including the JNK and P38 MAPK pathways. The expression and release of autocrine growth factor ligands, such as (transforming growth factor alpha) and TNF-alpha, following irradiation can also enhance the responses of MAPK pathways in cells and, consequently, of bystander cells. Thus, the ability of radiation to activate MAPK signaling pathways may depend on the expression of multiple growth factor receptors, autocrine factors and Ras mutation. Enhanced basal signaling by proto-oncogenes such as K-/H-/N-RAS may provide a radioprotective and growth-promoting signal. In many cell types, this may be via the PI3K pathway; in others, this may occur through nuclear factor-kappa B or multiple MAPK pathways. This review will describe the enzymes within the known MAPK signaling pathways and discuss their activation and roles in cellular radiation responses.
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Affiliation(s)
- Paul Dent
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA 23298-0058, USA.
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Ma BBY, Bristow RG, Kim J, Siu LL. Combined-modality treatment of solid tumors using radiotherapy and molecular targeted agents. J Clin Oncol 2003; 21:2760-76. [PMID: 12860956 DOI: 10.1200/jco.2003.10.044] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE Molecular targeted agents have been combined with radiotherapy (RT) in recent clinical trials in an effort to optimize the therapeutic index of RT. The appeal of this strategy lies in their potential target specificity and clinically acceptable toxicity. DESIGN This article integrates the salient, published research findings into the underlying molecular mechanisms, preclinical efficacy, and clinical applicability of combining RT with molecular targeted agents. These agents include inhibitors of intracellular signal transduction molecules, modulators of apoptosis, inhibitors of cell cycle checkpoints control, antiangiogenic agents, and cyclo-oxygenase-2 inhibitors. RESULTS Molecular targeted agents can have direct effects on the cytoprotective and cytotoxic pathways implicated in the cellular response to ionizing radiation (IR). These pathways involve cellular proliferation, DNA repair, cell cycle progression, nuclear transcription, tumor angiogenesis, and prostanoid-associated inflammation. These pathways can also converge to alter RT-induced apoptosis, terminal growth arrest, and reproductive cell death. Pharmacologic modulation of these pathways may potentially enhance tumor response to RT though inhibition of tumor repopulation, improvement of tumor oxygenation, redistribution during the cell cycle, and alteration of intrinsic tumor radiosensitivity. CONCLUSION Combining RT and molecular targeted agents is a rational approach in the treatment of solid tumors. Translation of this approach from promising preclinical data to clinical trials is actively underway.
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Affiliation(s)
- Brigette B Y Ma
- Department of Medical Oncology and Hematology, Precess Margaret Hospital, University Health Network, Suite 5-210, 610 University Ave, Toronto, Ontario, Canada M5G 2M9
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20
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Abstract
The use of antisense (AS) oligonucleotides as therapeutic agents was proposed as far back as the 1960s/1970s when the AS strategy was initially developed. However, it has taken almost a quarter of a century for this potential to be realized. The last few years has seen a rapid increase in the number of AS molecules progressing past Phase I in clinical trials, due in part to our increased knowledge of their structure and chemistry. Here, we describe the most prominent of these modifications with respect to clinical applicability. However, the main focus of this review is clinical application, with a focus on cancer. We will discuss in detail both the status of the current AS clinical trials and the molecules that are likely to be the targets of the next group of AS molecules entering the clinic.
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Affiliation(s)
- Kathleen F Pirollo
- Department of Oncology, Georgetown University Medical Center, Washington, DC 20007, USA
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21
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Grant S, Fisher PB, Dent P. The role of signal transduction pathways in drug and radiation resistance. Cancer Treat Res 2003; 112:89-108. [PMID: 12481713 DOI: 10.1007/978-1-4615-1173-1_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Affiliation(s)
- Steven Grant
- Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia, USA
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22
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Mas VMD, Hernandez H, Plo I, Bezombes C, Maestre N, Quillet-Mary A, Filomenko R, Demur C, Jaffrézou JP, Laurent G. Protein kinase Czeta mediated Raf-1/extracellular-regulated kinase activation by daunorubicin. Blood 2003; 101:1543-50. [PMID: 12406911 DOI: 10.1182/blood-2002-05-1585] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In light of the emerging concept of a protective function of the mitogen-activated protein kinase (MAPK) pathway under stress conditions, we investigated the influence of the anthracycline daunorubicin (DNR) on MAPK signaling and its possible contribution to DNR-induced cytotoxicity. We show that DNR increased phosphorylation of extracellular-regulated kinases (ERKs) and stimulated activities of both Raf-1 and extracellular-regulated kinase 1 (ERK1) within 10 to 30 minutes in U937 cells. ERK1 stimulation was completely blocked by either the mitogen-induced extracellular kinase (MEK) inhibitor PD98059 or the Raf-1 inhibitor 8-bromo-cAMP (cyclic adenosine monophosphate). However, only partial inhibition of Raf-1 and ERK1 stimulation was observed with the antioxidant N-acetylcysteine (N-Ac). Moreover, the xanthogenate compound D609 that inhibits DNR-induced phosphatidylcholine (PC) hydrolysis and subsequent diacylglycerol (DAG) production, as well as wortmannin that blocks phosphoinositide-3 kinase (PI3K) stimulation, only partially inhibited Raf-1 and ERK1 stimulation. We also observed that DNR stimulated protein kinase C zeta (PKCzeta), an atypical PKC isoform, and that both D609 and wortmannin significantly inhibited DNR-triggered PKCzeta activation. Finally, we found that the expression of PKCzeta kinase-defective mutant resulted in the abrogation of DNR-induced ERK phosphorylation. Altogether, these results demonstrate that DNR activates the classical Raf-1/MEK/ERK pathway and that Raf-1 activation is mediated through complex signaling pathways that involve at least 2 contributors: PC-derived DAG and PI3K products that converge toward PKCzeta. Moreover, we show that both Raf-1 and MEK inhibitors, as well as PKCzeta inhibition, sensitized cells to DNR-induced cytotoxicity.
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Affiliation(s)
- Véronique Mansat-De Mas
- Institut National de la Santé et de la Recherche Médicale U563, Institut Claudius Régaud, Toulouse, France.
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23
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Tumor-targeting, Systemically Delivered Antisense HER-2 Chemosensitizes Human Breast Cancer Xenografts Irrespective of HER-2 Levels. Mol Med 2002. [DOI: 10.1007/bf03402027] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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24
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Soldatenkov VA, Trofimova IN, Rouzaut A, McDermott F, Dritschilo A, Notario V. Differential regulation of the response to DNA damage in Ewing's sarcoma cells by ETS1 and EWS/FLI-1. Oncogene 2002; 21:2890-5. [PMID: 11973649 DOI: 10.1038/sj.onc.1205393] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2001] [Revised: 01/31/2002] [Accepted: 02/08/2002] [Indexed: 11/08/2022]
Abstract
Ewing's sarcoma (EWS) cells contain levels of poly(ADP-ribose) polymerase (PARP) significantly higher than other eukaryotic cells. Previously, we cloned the PARP gene promoter region from EWS cells, showed that it contained multiple ETS-binding sites and demonstrated a positive regulation of PARP by ETS1. We now report that, contrary to ETS1, EWS/FLI-1, an aberrant ETS transcription factor present in most EWS cells, is a negative effector of PARP transcription. Because PARP levels have been associated with cellular resistance or sensitivity to genotoxic agents, we studied the effect of modifying PARP levels in EWS cells on their response to DNA damage by modulating the expression of ETS1 or EWS/FLI-1 using antisense methodology. Results show that stable down-regulation of ETS1 increases the resistance of EWS cells to various genotoxic agents, whereas down-regulation of EWS/FLI-1 has pro-apoptotic effects. Because down-regulation EWS/FLI-1 does not dramatically change PARP levels, these results suggest a direct effect for EWS/FLI-1 in the DNA damage response of EWS cells. Since expression of the aberrant fusion proteins by EWS cells is essential for maintaining their neoplastic phenotype, our results suggest that the use of antisense oligonucleotides in combination with chemotherapeutic agents or radiation may be doubly effective by causing both an increase in sensitivity to therapeutic agents and a simultaneous down-regulation, or reversion, of the neoplastic phenotype of EWS cells.
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Affiliation(s)
- Viatcheslav A Soldatenkov
- Department of Radiation Medicine, Vincent T. Lombardi Cancer Center, Georgetown University Medical Center, Washington DC 20007, USA
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25
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Lau QC, Achenbach TV, Borchers O, Müller R, Slater EP. In vivo pro-apoptotic and antitumor efficacy of a c-Raf antisense phosphorothioate oligonucleotide: relationship to tumor size. ANTISENSE & NUCLEIC ACID DRUG DEVELOPMENT 2002; 12:11-20. [PMID: 12022686 DOI: 10.1089/108729002753670229] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Previously, we have shown that a phosphorothioate antisense oligonucleotide (ODN) targeted against c-raf RNA (ISIS5132; cRaf-AS) induces apoptosis in human tumor cells. We now show that the same ODN also efficiently triggers apoptosis in human tumor xenografts in nu/nu mice. Although cRaf-AS showed a clearly inhibitory effect on the growth of established tumors (approximately 150 mm3) compared to a mismatched control ODN (MM), tumor progression was not prevented. This correlated with a partial refractoriness of the tumor to cRaf-AS-induced cell killing, which seemed to be due to an inhomogeneous and inefficient penetration of the ODN into the tumor tissue rather than cellular resistance. In agreement with this conclusion, we found that growth of small tumors (<50 mm3) was completely inhibited concomitantly with an accumulation of the ODN throughout the tumor. These data show that the cRaf-AS is a highly efficacious antitumor agent, provided accessibility into the tumor tissue is warranted, and suggest that PS-AS-ODN treatment may be particularly useful in an adjuvant setting.
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Affiliation(s)
- Quek Choon Lau
- Institute of Molecular Biology and Tumor Research, Philipps University, Marburg, Germany
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26
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Aznar S, Lacal JC. Searching new targets for anticancer drug design: the families of Ras and Rho GTPases and their effectors. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2001; 67:193-234. [PMID: 11525383 DOI: 10.1016/s0079-6603(01)67029-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The Ras superfamily of low-molecular-weight GTPases are proteins that, in response to diverse stimuli, control key cellular processes such as cell growth and development, apoptosis, lipid metabolism, cytoarchitecture, membrane trafficking, and transcriptional regulation. More than 100 genes of this superfamily grouped in six subfamilies have been described so far, pointing to the complexities and specificities of their cellular functions. Dysregulation of members of at least two of these families (the Ras and the Rho families) is involved in the events that lead to the uncontrolled proliferation and invasiveness of human tumors. In recent years, the cloning and characterization of downstream effectors for Ras and Rho proteins have given crucial clues to the specific pathways that lead to aberrant cellular growth and ultimately to tumorigenesis. A direct link between the functions of some of these effectors with the appearance of transformed cells and their ability to proliferate and invade surrounding tissues has been made. Accordingly, drugs that specifically alter their functions display antineoplasic properties, and some of these drugs are already under clinical trials. In this review, we survey the progress made in understanding the underlying molecular connections between carcinogenesis and the specific cellular functions elicited by some of these effectors. We also discuss new drugs with antineoplastic or antimetastatic activity that are targeted to specific effectors for Ras or Rho proteins.
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Affiliation(s)
- S Aznar
- Instituto de Investigaciones Biomédicas, CSIC, Madrid, Spain
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27
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Dent P, Logsdon C, Nicke B, Valerie K, Farnsworth J, Schmidt-Ullrich R, Reardon DB. Recombinant adenoviral expression of dominant-negative Ras N17 blocking radiation-induced activation of mitogen-activated protein kinase pathway. Methods Enzymol 2001; 333:28-37. [PMID: 11400343 DOI: 10.1016/s0076-6879(01)33041-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
MESH Headings
- Adenoviridae/genetics
- Animals
- Blotting, Western
- Cells, Cultured
- Electrophoresis, Polyacrylamide Gel
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Gene Expression Regulation, Enzymologic/radiation effects
- Genes, erbB-1/genetics
- Genes, erbB-1/radiation effects
- Genes, ras/genetics
- Genes, ras/radiation effects
- Humans
- Mitogen-Activated Protein Kinases/genetics
- Mitogen-Activated Protein Kinases/metabolism
- Mitogen-Activated Protein Kinases/radiation effects
- Radiation, Ionizing
- Recombination, Genetic
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Affiliation(s)
- P Dent
- Department of Radiation Oncology, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia 23298-0058, USA
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28
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Leonetti C, Biroccio A, Benassi B, Stringaro A, Stoppacciaro A, Semple SC, Zupi G. Encapsulation of c-myc antisense oligodeoxynucleotides in lipid particles improves antitumoral efficacy in vivo in a human melanoma line. Cancer Gene Ther 2001; 8:459-68. [PMID: 11498766 DOI: 10.1038/sj.cgt.7700326] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2001] [Indexed: 11/09/2022]
Abstract
Phosphorothioate c-myc antisense oligodeoxynucleotides [S]ODNs (free INX-6295) were encapsulated in a new liposome formulation and the antitumor activity was compared to the unencapsulated antisense in a human melanoma xenograft. The systemic administration of INX-6295 encapsulated in stabilized antisense lipid particles (SALP INX-6295) improved plasma AUC (area under the plasma concentration-time curve) and initial half-life of free INX-6295, resulting in a significant enhancement in tumor accumulation and improvement in tumor distribution of antisense oligodeoxynucleotides. Animals treated with SALP INX-6295 exhibited a prolonged reduction of c-myc expression, reduced tumor growth and increased mice survival. When administered in combination with cisplatin (DDP), SALP INX-6295 produced a complete tumor regression in approximately 30% of treated mice, which persisted for at least 60 days following the first cycle of treatment. Finally, the median survival of mice treated with DDP/SALP INX-6295 increased by 105% compared to 84% for animals treated with the combination DDP/free INX-6295. These data indicate that the biological activity and the therapeutic efficacy of c-myc antisense therapy may be improved when these agents are administered in lipid-based delivery systems.
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Affiliation(s)
- C Leonetti
- Experimental Chemotherapy Laboratory, Regina Elena Cancer Institute, 00158 Rome, Italy.
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29
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Abstract
Developments in cellular and molecular biology in the past decade have increased our understanding of the processes by which cells respond to ionising radiation. Cells use complex protein signalling systems that recognise radiation damage to DNA and plasma membrane lipids. When damage is found, it leads to the activation of various intracellular pathways that modulate the activity of genes controlling ceflular responses such as apoptosis, cell-cycle arrest, or repair. Numerous molecular targets may be activated or inhibited in an attempt to upregulatre or downregulate the radiation response. In this review, we discuss some of the new compounds and techniques for manipulating the cell's response to radiation.
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30
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Park JS, Qiao L, Su ZZ, Hinman D, Willoughby K, McKinstry R, Yacoub A, Duigou GJ, Young CS, Grant S, Hagan MP, Ellis E, Fisher PB, Dent P. Ionizing radiation modulates vascular endothelial growth factor (VEGF) expression through multiple mitogen activated protein kinase dependent pathways. Oncogene 2001; 20:3266-80. [PMID: 11423976 DOI: 10.1038/sj.onc.1204258] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2000] [Revised: 01/03/2001] [Accepted: 01/07/2001] [Indexed: 11/09/2022]
Abstract
We investigated the role of radiation-induced mitogen activated protein kinase (MAPK) pathway activity in the regulation of proliferation, cell survival and vascular endothelial growth factor (VEGF) production in primary astrocytes and in T9 and RT2 glioblastoma cells derived from Fisher 344 rats. In these cells, ionizing radiation (2 Gy) caused activation of the MAPK pathway which was blocked by specific inhibitor drugs. Blunting of radiation-induced MAPK activity weakly enhanced radiation-induced apoptosis 24 h after exposure in RT2 cells. Furthermore, blunting of MAPK activation weakly enhanced the ability of radiation to reduce RT2 cell growth in clonogenic growth assays. These findings argue that inhibition of MAPK signaling reduces proliferation and enhances cell killing by ionizing radiation in transformed astrocytes. Proliferation and survival of cancer cells has been linked in vivo to enhanced expression of angiogenic growth factors. Recently we demonstrated that the gene product of a novel rodent radiation-responsive gene, progression elevated gene 3 (PEG-3), could enhance vascular endothelial growth factor (VEGF) promoter activity in rodent fibroblasts, leading to increased VEGF protein levels and tumorigenic behavior in vivo. Thus PEG-3 and VEGF expression could be expected to directly correlate with the oncogenic potential of transformed cells. RT2 cells expressed more PEG-3 and VEGF protein than T9 cells, and were more tumorigenic in vivo than T9 cells. Radiation activated the PEG-3 promoter via MAPK signaling and ectopic over-expression of PEG-3 enhanced both basal MAPK activity and basal VEGF promoter activity. Basal MAPK activity partially correlated with basal VEGF promoter activity and VEGF protein levels in primary astrocytes, T9 and RT2 cells. Radiation increased the activity of the VEGF promoter and VEGF protein levels in primary astrocytes, T9 and RT2 cells which were dependent upon MAPK function. Furthermore, inhibition of AP-1 transcription factor signaling by dominant negative c-Jun (TAM67) also significantly reduced basal, and to a lesser extent radiation-induced, VEGF promoter function in RT2 cells. Collectively, our data demonstrate that radiation-induced MAPK signaling can both protect cells from radiation-induced cell death as well as enhance protein levels of pro-angiogenic factors such as VEGF. Enhanced VEGF expression in RT2 cells may be mediated via MAPK and JNK pathway signaling which converges upon the AP-1 transcription factor complex.
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Affiliation(s)
- J S Park
- Department of Radiation Oncology, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia, VA 23298, USA
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31
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Leszczyniecka M, Roberts T, Dent P, Grant S, Fisher PB. Differentiation therapy of human cancer: basic science and clinical applications. Pharmacol Ther 2001; 90:105-56. [PMID: 11578655 DOI: 10.1016/s0163-7258(01)00132-2] [Citation(s) in RCA: 228] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Current cancer therapies are highly toxic and often nonspecific. A potentially less toxic approach to treating this prevalent disease employs agents that modify cancer cell differentiation, termed 'differentiation therapy.' This approach is based on the tacit assumption that many neoplastic cell types exhibit reversible defects in differentiation, which upon appropriate treatment, results in tumor reprogramming and a concomitant loss in proliferative capacity and induction of terminal differentiation or apoptosis (programmed cell death). Laboratory studies that focus on elucidating mechanisms of action are demonstrating the effectiveness of 'differentiation therapy,' which is now beginning to show translational promise in the clinical setting.
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Affiliation(s)
- M Leszczyniecka
- Department of Urology, Herbert Irving Comprehensive Cancer Center, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA
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32
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Funato T, Kozawa K, Fujimaki S, Kaku M. Increased sensitivity to cytosine arabinoside in human leukemia by c-raf-1 antisense oligonucleotides. Anticancer Drugs 2001; 12:325-9. [PMID: 11335788 DOI: 10.1097/00001813-200104000-00004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
c-raf-1, a cytoplasmic serine/threonine protein kinase, plays an important role in mitogen- and damage-responsive cellular signal transduction pathways. Expression of c-raf-1 modifies cell growth, proliferation and survival. Although expression of c-raf-1 has been studied in several tumors, the role of c-raf-1 in leukemia is so far unclear. We examined the expression of c-raf-1 in the human leukemia cell lines U937 and K562, and in a cytosine arabinoside (Ara-C)-resistant cell line (K562AC) derived from K562. Expression of c-raf-1 was increased in U937 and in Ara-C-resistant K562AC cells compared with the parental cells. We then investigated whether inhibition of c-raf-1 expression by antisense oligonucleotides increases the sensitivity to Ara-C in U937 and K562AC cells. Antisense oligonucleotides for c-raf-1 inhibited expression of c-raf-1 mRNA, but did not affect cell growth and increased sensitivity to Ara-C but not to other drugs such as adriamycin, VP-16 or vincristine. These results suggest that c-raf-1 is one of the factors involved in Ara-C resistance in leukemia and lend weight to the case for development of anti-cancer therapeutics involving oncogene-targeted antisense oligonucleotides.
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Affiliation(s)
- T Funato
- Division of Molecular Diagnostics, Department of Clinical Medicine, Tohoku University, School of Medicine, Seiryoumachi 1-1, Aoba-ku, Sendai 980-8574, Japan.
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33
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Affiliation(s)
- B P Monia
- Isis Pharmaceuticals, Carlsbad, California, USA.
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34
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Abstract
Exposure of cells to ionizing radiation results in complex cellular responses resulting in cell death and altered proliferation states. The underlying cytotoxic, cytoprotective and cellular stress responses to radiation are mediated by existing signaling pathways, activation of which may be amplified by intrinsic cellular radical production systems. These signaling responses include the activation of plasma membrane receptors, the stimulation of cytoplasmic protein kinases, transcriptional activation, and altered cell cycle regulation. From the data presented, there is increasing evidence for the functional links between cellular signal transduction responses and DNA damage recognition and repair, cell survival, or cell death through apoptosis or reproductive mechanisms.
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Affiliation(s)
- R K Schmidt-Ullrich
- Department of Radiation Oncology Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia 23298, USA
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35
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End DW. Farnesyl protein transferase inhibitors and other therapies targeting the Ras signal transduction pathway. Invest New Drugs 2000; 17:241-58. [PMID: 10665477 DOI: 10.1023/a:1006380320290] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The year 2000 will be a significant date for the field of Ras-related therapies since numerous agents will have Phase II clinical efficacy data maturing to provide proof of principle for this cancer treatment strategy. These data will also provide an important milestone for the cancer research community since these molecules represent a small vanguard of oncology drug discovery projects predicated on molecular targets. We can only hope that these agents are a successful harbinger for the formidable number of targeted therapies that will be entering development pipelines in the coming years.
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Affiliation(s)
- D W End
- Department of Oncology, Janssen Research Foundation, Spring House, PA 19477, USA.
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36
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Kumar D, Whiteside TL, Kasid U. Identification of a novel tumor necrosis factor-alpha-inducible gene, SCC-S2, containing the consensus sequence of a death effector domain of fas-associated death domain-like interleukin- 1beta-converting enzyme-inhibitory protein. J Biol Chem 2000; 275:2973-8. [PMID: 10644768 DOI: 10.1074/jbc.275.4.2973] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We report here the isolation and characterization of a novel tumor necrosis factor-alpha (TNF-alpha)-inducible gene, SCC-S2. Based on the nucleotide sequence, the SCC-S2 open reading frame contains a sequence in the amino terminus that shows a significant homology to death effector domain II of cell death regulatory protein, Fas-associated death domain-like interleukin-1beta-converting enzyme-inhibitory protein (FLIP). Unlike FLIP, the SCC-S2 open reading frame contains only one death effector domain and lacks the carboxyl-terminal caspase-like homology domain, raising the possibility that SCC-S2 may be a novel member of the FLIP family. SCC-S2 mRNA expression is found in most normal tissues and malignant cells. The steady state level of SCC-S2 mRNA is significantly induced by TNF-alpha in different tumor cells (TNF-alpha at 20 ng/ml for 3 h: A549, approximately 2-9-fold; SKOV-3, approximately 3-fold; PCI-04A, approximately 3-6-fold). TNF-alpha treatment (100 ng/ml, 4 h) of HeLa cells transiently transfected with FLAG epitope-tagged SCC-S2 cDNA or expression vector alone led to an increase in the number of apoptotic cells as compared with the untreated counterpart. Interestingly, however, SCC-S2 transfectants revealed a significant decrease in the number of apoptotic cells as compared with the vector transfectants (p < 0.001). These data implicate a role of SCC-S2 as a negative mediator of apoptosis in certain cell types.
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Affiliation(s)
- D Kumar
- Department of Radiation Medicine, Lombardi Cancer Center, Georgetown University Medical Center, Washington, D.C. 20007, USA
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