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Prakash DL, Gosavi S. The diversity of protein-protein interaction interfaces within T=3 icosahedral viral capsids. Front Mol Biosci 2022; 9:967877. [PMID: 36339706 PMCID: PMC9631432 DOI: 10.3389/fmolb.2022.967877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 09/08/2022] [Indexed: 11/20/2022] Open
Abstract
Some non-enveloped virus capsids assemble from multiple copies of a single type of coat-protein (CP). The comparative energetics of the diverse CP-CP interfaces present in such capsids likely govern virus assembly-disassembly mechanisms. The T = 3 icosahedral capsids comprise 180 CP copies arranged about two-, three-, five- and six-fold axes of (quasi-)rotation symmetry. Structurally diverse CPs can assemble into T = 3 capsids. Specifically, the Leviviridae CPs are structurally distinct from the Bromoviridae, Tombusviridae and Tymoviridae CPs which fold into the classic “jelly-roll” fold. However, capsids from across the four families are known to disassemble into dimers. To understand whether the overall symmetry of the capsid or the structural details of the CP determine virus assembly-disassembly mechanisms, we analyze the different CP-CP interfaces that occur in the four virus families. Previous work studied protein homodimer interfaces using interface size (relative to the monomer) and hydrophobicity. Here, we analyze all CP-CP interfaces using these two parameters and find that the dimerization interface (present between two CPs congruent through a two-fold axis of rotation) has a larger relative size in the Leviviridae than in the other viruses. The relative sizes of the other Leviviridae interfaces and all the jelly-roll interfaces are similar. However, the dimerization interfaces across families have slightly higher hydrophobicity, potentially making them stronger than other interfaces. Finally, although the CP-monomers of the jelly-roll viruses are structurally similar, differences in their dimerization interfaces leads to varied dimer flexibility. Overall, differences in CP-structures may induce different modes of swelling and assembly-disassembly in the T = 3 viruses.
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Lalwani Prakash D, Gosavi S. Understanding the Folding Mediated Assembly of the Bacteriophage MS2 Coat Protein Dimers. J Phys Chem B 2021; 125:8722-8732. [PMID: 34339197 DOI: 10.1021/acs.jpcb.1c03928] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The capsids of RNA viruses such as MS2 are great models for studying protein self-assembly because they are made almost entirely of multiple copies of a single coat protein (CP). Although CP is the minimal repeating unit of the capsid, previous studies have shown that CP exists as a homodimer (CP2) even in an acid-disassembled system, indicating that CP2 is an obligate dimer. Here, we investigate the molecular basis of this obligate dimerization using coarse-grained structure-based models and molecular dynamics simulations. We find that, unlike monomeric proteins of similar size, CP populates a single partially folded ensemble whose "foldedness" is sensitive to denaturing conditions. In contrast, CP2 folds similarly to single-domain proteins populating only the folded and the unfolded ensembles, separated by a prominent folding free energy barrier. Several intramonomer contacts form early, but the CP2 folding barrier is crossed only when the intermonomer contacts are made. A dissection of the structure of CP2 through mutant folding simulations shows that the folding barrier arises both from the topology of CP and the interface contacts of CP2. Together, our results show that CP2 is an obligate dimer because of kinetic stability, that is, dimerization induces a folding barrier and that makes it difficult for proteins in the dimer minimum to partially unfold and access the monomeric state without completely unfolding. We discuss the advantages of this obligate dimerization in the context of dimer design and virus stability.
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Affiliation(s)
- Digvijay Lalwani Prakash
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
| | - Shachi Gosavi
- Simons Centre for the Study of Living Machines, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, India
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Guo N, Gao C, Liu J, Li J, Liu N, Hao Y, Chen L, Zhang X. Reversal of Ovarian Cancer Multidrug Resistance by a Combination of LAH4-L1-siMDR1 Nanocomplexes with Chemotherapeutics. Mol Pharm 2018; 15:1853-1861. [PMID: 29621396 DOI: 10.1021/acs.molpharmaceut.8b00031] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Nana Guo
- Collaborative Innovation Center for Biotherapy, Tsinghua University, Beijing 100084, China
- Anhui Medical University, Hefei, Anhui 230032, China
- Department of Gynaecology and Obstetrics, PLA Navy General Hospital, Beijing 100037, China
| | - Chen Gao
- College of Life Science, Hebei Normal University, Shijiazhuang, Hebei 050024, China
| | - Jing Liu
- Collaborative Innovation Center for Biotherapy, Tsinghua University, Beijing 100084, China
| | - Jun Li
- School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, China
| | - Nan Liu
- School of Medicine, Tsinghua University, Beijing 100084, China
| | - Yanli Hao
- School of Medicine, Tsinghua University, Beijing 100084, China
| | - Lei Chen
- Anhui Medical University, Hefei, Anhui 230032, China
- Department of Gynaecology and Obstetrics, PLA Navy General Hospital, Beijing 100037, China
| | - Xiaoning Zhang
- Collaborative Innovation Center for Biotherapy, Tsinghua University, Beijing 100084, China
- School of Medicine, Tsinghua University, Beijing 100084, China
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Hussain M, Zhou Y, Song Y, Hameed HMA, Jiang H, Tu Y, Zhang J. ATAD2 in cancer: a pharmacologically challenging but tractable target. Expert Opin Ther Targets 2017; 22:85-96. [PMID: 29148850 DOI: 10.1080/14728222.2018.1406921] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
INTRODUCTION ATAD2 protein is an emerging oncogene that has strongly been linked to the etiology of multiple advanced human cancers. Therapeutically, despite the fact that genetic suppression/knockdown studies have validated it as a compelling drug target for future therapeutic development, recent druggability assessment data suggest that direct targeting of ATAD2's bromodomain (BRD) may be a very challenging task. ATAD2's BRD has been predicted as a 'difficult to drug' or 'least druggable' target due to the concern that its binding pocket, and the areas around it, seem to be unfeasible for ligand binding. Areas covered: In this review, after shedding light on the multifaceted roles of ATAD2 in normal physiology as well as in cancer-etiology, we discuss technical challenges rendered by ATAD2's BRD active site and the recent drug discovery efforts to find small molecule inhibitors against it. Expert opinion: The identification of a novel low-nanomolar semi-permeable chemical probe against ATAD2's BRD by recent drug discovery campaign has demonstrated it to be a pharmacologically tractable target. Nevertheless, the development of high quality bioavailable inhibitors against ATAD2 is still a pending task. Moreover, ATAD2 may also potentially be utilized as a promising target for future development of RNAi-based therapy to treat cancers.
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Affiliation(s)
- Muzammal Hussain
- a State Key Laboratory of Respiratory Disease , Guangzhou Institutes of Biomedicine and Heath, Chinese Academy of Sciences , Guangzhou , PR China.,b Guangdong Provincial Key Laboratory of Biocomputing, Institute of Chemical Biology , Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences , Guangzhou China.,c University of Chinese Academy of Sciences , Beijing , PR China
| | - Yang Zhou
- d Division of Theoretical Chemistry and Biology, School of Biotechnology , Royal Institute of Technology (KTH), AlbaNova University Center , Stockholm , Sweden
| | - Yu Song
- e Basic Medical College of Beihua University , Jilin , China
| | - H M Adnan Hameed
- a State Key Laboratory of Respiratory Disease , Guangzhou Institutes of Biomedicine and Heath, Chinese Academy of Sciences , Guangzhou , PR China.,c University of Chinese Academy of Sciences , Beijing , PR China
| | - Hao Jiang
- a State Key Laboratory of Respiratory Disease , Guangzhou Institutes of Biomedicine and Heath, Chinese Academy of Sciences , Guangzhou , PR China.,b Guangdong Provincial Key Laboratory of Biocomputing, Institute of Chemical Biology , Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences , Guangzhou China
| | - Yaoquan Tu
- d Division of Theoretical Chemistry and Biology, School of Biotechnology , Royal Institute of Technology (KTH), AlbaNova University Center , Stockholm , Sweden
| | - Jiancun Zhang
- a State Key Laboratory of Respiratory Disease , Guangzhou Institutes of Biomedicine and Heath, Chinese Academy of Sciences , Guangzhou , PR China.,b Guangdong Provincial Key Laboratory of Biocomputing, Institute of Chemical Biology , Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences , Guangzhou China
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5
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Bjorge JD, Pang A, Fujita DJ. Delivery of gene targeting siRNAs to breast cancer cells using a multifunctional peptide complex that promotes both targeted delivery and endosomal release. PLoS One 2017; 12:e0180578. [PMID: 28666009 PMCID: PMC5493434 DOI: 10.1371/journal.pone.0180578] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 06/16/2017] [Indexed: 12/21/2022] Open
Abstract
RNA interference has been used to dissect the importance of individual gene products in various human disease processes, including cancer. Small-interfering RNA, or siRNA, is one of the tools utilized in this regard, but specially-designed delivery agents are required to allow the siRNA to gain optimal access to the cell interior. Our laboratory has utilized two different siRNA-binding delivery peptides containing a polyarginine core, and modified by myristoylation and targeting motifs (iRGD or Lyp-1). A third peptide was designed to assist with endosomal release. Various ratios of the peptides and siRNA were combined and assayed for the ability to form stable complexes, and optimized ratios were determined. The complexes were found to form particles, with the majority having a diameter of 100-300 nm, as visualized by electron microscopy. These siRNA complexes have enhanced protection from nucleases present in serum, as compared to "naked" unprotected siRNA. The particles were internalized by the cells and could be detected in the cell cytoplasm by confocal fluorescence microscopy. In functional assays, peptide/siRNA complexes were shown to cause the knock down of corresponding targeted proteins. The peptide with the LyP-1 targeting motif was more effective at knockdown in MDA-MB-231 breast cancer cells than the peptide with the iRGD motif. Inclusion of the endosomal release peptide in the complexes greatly enhanced the peptide/siRNA effects. Peptide/siRNA complexes simultaneously targeting Stat3 and c-Myc caused a marked reduction in anchorage-independent growth, a property correlated with tumorigenicity. This study demonstrates the ability of a peptide-based siRNA-delivery system to deliver siRNA into breast cancer cells and cause both protein knockdown and suppression of the malignant phenotype. Such peptide complexes are likely to become highly useful siRNA-delivery vehicles for the characterization, and potentially for the treatment, of human cancer.
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Affiliation(s)
- Jeffrey D. Bjorge
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- The Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- * E-mail: (JDB); (DF)
| | - Andy Pang
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- The Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Donald J. Fujita
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- The Arnie Charbonneau Cancer Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- * E-mail: (JDB); (DF)
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6
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Iyer SV, Parrales A, Begani P, Narkar A, Adhikari AS, Martinez LA, Iwakuma T. Allele-specific silencing of mutant p53 attenuates dominant-negative and gain-of-function activities. Oncotarget 2016; 7:5401-15. [PMID: 26700961 PMCID: PMC4868694 DOI: 10.18632/oncotarget.6634] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 12/12/2015] [Indexed: 12/19/2022] Open
Abstract
Many p53 hotspot mutants not only lose the transcriptional activity, but also show dominant-negative (DN) and oncogenic gain-of-function (GOF) activities. Increasing evidence indicates that knockdown of mutant p53 (mutp53) in cancer cells reduces their aggressive properties, suggesting that survival and proliferation of cancer cells are, at least partially, dependent on the presence of mutp53. However, these p53 siRNAs can downregulate both wild-type p53 (wtp53) and mutp53, which limits their therapeutic applications. In order to specifically deplete mutp53, we have developed allele-specific siRNAs against p53 hotspot mutants and validated their biological effects in the absence or presence of wtp53. First, the mutp53-specific siRNAs selectively reduced protein levels of matched p53 mutants with minimal reduction in wtp53 levels. Second, downregulation of mutp53 in cancer cells expressing a mutp53 alone (p53mut) resulted in significantly decreased cell proliferation and migration. Third, transfection of mutp53-specific siRNAs in cancer cells expressing both wtp53 and mutp53 also reduced cell proliferation and migration with increased transcripts of p53 downstream target genes, which became further profound when cells were treated with an MDM2 inhibitor Nutlin-3a or a chemotherapeutic agent doxorubicin. These results indicate that depletion of mutp53 by its specific siRNA restored endogenous wtp53 activity in cells expressing both wtp53 and mutp53. This is the first study demonstrating biological effects and therapeutic potential of allele-specific silencing of mutp53 by mutp53-specific siRNAs in cancer cells expressing both wtp53 and mutp53, thus providing a novel strategy towards targeted cancer therapies.
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Affiliation(s)
- Swathi V Iyer
- Department of Cancer Biology, The University of Kansas Cancer Center, University of Kansas Medical Center, Kansas City, KS, USA
| | - Alejandro Parrales
- Department of Cancer Biology, The University of Kansas Cancer Center, University of Kansas Medical Center, Kansas City, KS, USA
| | - Priya Begani
- Department of Cancer Biology, The University of Kansas Cancer Center, University of Kansas Medical Center, Kansas City, KS, USA
| | - Akshay Narkar
- Department of Cancer Biology, The University of Kansas Cancer Center, University of Kansas Medical Center, Kansas City, KS, USA
| | - Amit S Adhikari
- Center for Advanced Preclinical Research, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
| | - Luis A Martinez
- Department of Pathology, Stony Brook School of Medicine, Stony Brook, NY, USA
| | - Tomoo Iwakuma
- Department of Cancer Biology, The University of Kansas Cancer Center, University of Kansas Medical Center, Kansas City, KS, USA
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7
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Pumpens P, Renhofa R, Dishlers A, Kozlovska T, Ose V, Pushko P, Tars K, Grens E, Bachmann MF. The True Story and Advantages of RNA Phage Capsids as Nanotools. Intervirology 2016; 59:74-110. [DOI: 10.1159/000449503] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 08/30/2016] [Indexed: 11/19/2022] Open
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8
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Werner K, Lademann F, Thepkaysone ML, Jahnke B, Aust DE, Kahlert C, Weber G, Weitz J, Grützmann R, Pilarsky C. Simultaneous gene silencing of KRAS and anti-apoptotic genes as a multitarget therapy. Oncotarget 2016; 7:3984-92. [PMID: 26716649 PMCID: PMC4826184 DOI: 10.18632/oncotarget.6766] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 11/29/2015] [Indexed: 12/28/2022] Open
Abstract
Pancreatic cancer is one of the most lethal tumor types worldwide and an effective therapy is still elusive. Targeted therapy focused against a specific alteration is by definition unable to attack broad pathway signaling modification. Tumor heterogeneity will render targeted therapies ineffective based on the regrowth of cancer cell sub-clones. Therefore multimodal therapy strategies, targeting signaling pathways simultaneously should improve treatment. SiRNAs against KRAS and the apoptosis associated genes BCLXL, FLIP, MCL1L, SURVIVIN and XIAP were transfected into human and murine pancreatic cancer cell lines. Induction of apoptosis was measured by Caspase 3/7 activation, subG1 FACS analysis and PARP cleavage. The therapeutic approach was tested in a subcutaneous allograft model with a murine cancer cell line. By using siRNAs as a systematic approach to remodel signal transduction in pancreatic cancer the results showed increasing inhibition of proliferation and apoptosis induction in vitro and in vivo. Thus, siRNAs are suitable to model multimodal therapy against signaling pathways in pancreatic cancer. Improvements in in vivo delivery of siRNAs against a multitude of targets might therefore be a potential therapeutic approach.
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Affiliation(s)
- Kristin Werner
- Department of Visceral, Thoracic and Vascular Surgery, TU Dresden, 01307 Dresden, Germany
| | - Franziska Lademann
- Department of Visceral, Thoracic and Vascular Surgery, TU Dresden, 01307 Dresden, Germany
| | - May-Linn Thepkaysone
- Department of Visceral, Thoracic and Vascular Surgery, TU Dresden, 01307 Dresden, Germany
| | - Beatrix Jahnke
- Department of Visceral, Thoracic and Vascular Surgery, TU Dresden, 01307 Dresden, Germany
| | - Daniela E Aust
- Institute of Pathology, TU Dresden, 01307 Dresden, Germany
| | - Christoph Kahlert
- Department of Visceral, Thoracic and Vascular Surgery, TU Dresden, 01307 Dresden, Germany
| | - Georg Weber
- Department of Surgery, Universitätsklinikum Erlangen, 91054 Erlangen, Germany
| | - Jürgen Weitz
- Department of Visceral, Thoracic and Vascular Surgery, TU Dresden, 01307 Dresden, Germany
| | - Robert Grützmann
- Department of Surgery, Universitätsklinikum Erlangen, 91054 Erlangen, Germany
| | - Christian Pilarsky
- Department of Visceral, Thoracic and Vascular Surgery, TU Dresden, 01307 Dresden, Germany
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Lu Y, Wang Y, Zhang M, Liu L, Li F, Zhang J, Ye M, Zhao H, Zhao J, Yan B, Yang A, Zhang R, Li X, Ren X. HER2-siRNA delivered by EGFR-specific single chain antibody inhibits NSCLC cell proliferation and tumor growth. Oncotarget 2016; 7:23594-607. [PMID: 26988752 PMCID: PMC5029650 DOI: 10.18632/oncotarget.8053] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 02/29/2016] [Indexed: 12/25/2022] Open
Abstract
Overexpression of human epidermal growth factor receptor type2 (HER2) is closely associated with aggressive progression and poor prognosis in non-small cell lung cancer (NSCLC). Here, we generated an EGFR-scFv-arginine nonamer peptide fusion protein (scFv-9R) as a cargo to deliver HER2 specific siRNA into HER2-positive NSCLC cells both in vitro and in vivo. HER2-siRNAs delivered by scFv-9R effeciently silenced HER2 expression in EGFR-positive NSCLC cells, and consequently resulted in G1 arrest and cell growth inhibition. Importantly, intravenous injection of scFv-9R/HER2-siRNA complex markedly suppressed growth of EGFR-positive NSCLC xenograft in nude mice, resulting from downregulated HER2 expression, reduced cell proliferation and enhanced cell apoptosis. Collectively, our study provides a novel therapeutic strategy for the treatment of EGFR-positive, HER2-overexpressed NSCLC.
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MESH Headings
- Adenocarcinoma/genetics
- Adenocarcinoma/prevention & control
- Adenocarcinoma/secondary
- Animals
- Apoptosis
- Biomarkers, Tumor
- Carcinoma, Non-Small-Cell Lung/genetics
- Carcinoma, Non-Small-Cell Lung/prevention & control
- Carcinoma, Non-Small-Cell Lung/secondary
- Carcinoma, Squamous Cell/genetics
- Carcinoma, Squamous Cell/prevention & control
- Carcinoma, Squamous Cell/secondary
- Cell Cycle
- Cell Proliferation
- ErbB Receptors/immunology
- Female
- Follow-Up Studies
- Humans
- Lung Neoplasms/genetics
- Lung Neoplasms/pathology
- Lung Neoplasms/prevention & control
- Lymphatic Metastasis
- Male
- Mice
- Mice, Inbred BALB C
- Mice, Nude
- Middle Aged
- Neoplasm Invasiveness
- Prognosis
- RNA, Small Interfering/administration & dosage
- RNA, Small Interfering/genetics
- Receptor, ErbB-2/antagonists & inhibitors
- Receptor, ErbB-2/genetics
- Single-Chain Antibodies/pharmacology
- Survival Rate
- Tumor Cells, Cultured
- Xenograft Model Antitumor Assays
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Affiliation(s)
- Yuan Lu
- Department of Respiratory Medicine, Xijing Hospital, Fourth Military Medical University, Xi’an, China
| | - Yuan Wang
- Department of Respiratory Medicine, Xijing Hospital, Fourth Military Medical University, Xi’an, China
| | - Mi Zhang
- Department of Respiratory Medicine, PLA General Hospital, Beijing, China
| | - Li Liu
- Department of Respiratory Medicine, Xijing Hospital, Fourth Military Medical University, Xi’an, China
- Department of Geriatrics, Xianyang Central Hospital, Xianyang, China
| | - Fakai Li
- Department of Respiratory Medicine, Xijing Hospital, Fourth Military Medical University, Xi’an, China
| | - Jian Zhang
- Department of Respiratory Medicine, Xijing Hospital, Fourth Military Medical University, Xi’an, China
| | - Mingxiang Ye
- Department of Respiratory Medicine, Xijing Hospital, Fourth Military Medical University, Xi’an, China
| | - Hu Zhao
- Organ Transplant Institute, Fuzhou General Hospital (DongFang Hospital), Xiamen University, Fuzhou, China
| | - Jing Zhao
- State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi’an, China
| | - Bo Yan
- State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi’an, China
| | - Angang Yang
- State Key Laboratory of Cancer Biology, Department of Immunology, Fourth Military Medical University, Xi’an, China
| | - Rui Zhang
- State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi’an, China
| | - Xia Li
- State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, Fourth Military Medical University, Xi’an, China
| | - Xinling Ren
- Department of Respiratory Medicine, Xijing Hospital, Fourth Military Medical University, Xi’an, China
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Loss of β-catenin in adrenocortical cancer cells causes growth inhibition and reversal of epithelial-to-mesenchymal transition. Oncotarget 2016; 6:11421-33. [PMID: 25823656 PMCID: PMC4484466 DOI: 10.18632/oncotarget.3222] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 01/26/2015] [Indexed: 01/11/2023] Open
Abstract
Adrenal carcinoma (ACC) is a rare neoplasm with a poor outcome. Aberrant expression of β-catenin has been found in approximatively 30% of ACC. We herein studied its effects on the growth of the human ACC cell line H295R. The cells were infected with short hairpin RNA (shRNA)-mediated silencing β-catenin. Two shRNAs used induced down-regulation of β-catenin protein levels. The expression of these shRNAs decreased cell growth and increased H295R cells in S and G2/M phases. This cytostatic effect is due to a decrease of phosphorylated MAPK and to an up-regulation expression of the cyclin-dependent kinase inhibitors p57KIP2, p21CIP and p27KIP1. In addition, the knockdown of β-catenin decreased phosphorylated Akt and increased apoptosis. Finally, loss of β-catenin was sufficient to induce the reversal of the epithelial-to-mesenchymal transition. We then transplanted these genetically modified H295R cells in Scid mice. Tumor growth suppression was achieved by the two shRNAs showing in vitro efficacy. Proliferation was not reduced in silenced tumors. In contrast, p57, p27 and p21 proteins were found expressed at high levels in silenced tumors along with an increase in apoptotic cells. These findings indicate that β-catenin loss in H295R cells inhibits tumor growth by inducing transcriptional and functional changes.
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11
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An S, Jiang X, Shi J, He X, Li J, Guo Y, Zhang Y, Ma H, Lu Y, Jiang C. Single-component self-assembled RNAi nanoparticles functionalized with tumor-targeting iNGR delivering abundant siRNA for efficient glioma therapy. Biomaterials 2015; 53:330-40. [DOI: 10.1016/j.biomaterials.2015.02.084] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 02/16/2015] [Accepted: 02/19/2015] [Indexed: 11/26/2022]
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12
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Catenacci DVT. Next-generation clinical trials: Novel strategies to address the challenge of tumor molecular heterogeneity. Mol Oncol 2015; 9:967-96. [PMID: 25557400 PMCID: PMC4402102 DOI: 10.1016/j.molonc.2014.09.011] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/23/2014] [Accepted: 09/26/2014] [Indexed: 02/09/2023] Open
Abstract
The promise of 'personalized cancer care' with therapies toward specific molecular aberrations has potential to improve outcomes. However, there is recognized heterogeneity within any given tumor-type from patient to patient (inter-patient heterogeneity), and within an individual (intra-patient heterogeneity) as demonstrated by molecular evolution through space (primary tumor to metastasis) and time (after therapy). These issues have become hurdles to advancing cancer treatment outcomes with novel molecularly targeted agents. Classic trial design paradigms are challenged by heterogeneity, as they are unable to test targeted therapeutics against low frequency genomic 'oncogenic driver' aberrations with adequate power. Usual accrual difficulties to clinical trials are exacerbated by low frequencies of any given molecular driver. To address these challenges, there is need for innovative clinical trial designs and strategies implementing novel diagnostic biomarker technologies to account for inter-patient molecular diversity and scarce tissue for analysis. Importantly, there is also need for pre-defined treatment priority algorithms given numerous aberrations commonly observed within any one individual sample. Access to multiple available therapeutic agents simultaneously is crucial. Finally intra-patient heterogeneity through time may be addressed by serial biomarker assessment at the time of tumor progression. This report discusses various 'next-generation' biomarker-driven trial designs and their potentials and limitations to tackle these recognized molecular heterogeneity challenges. Regulatory hurdles, with respect to drug and companion diagnostic development and approval, are considered. Focus is on the 'Expansion Platform Design Types I and II', the latter demonstrated with a first example, 'PANGEA: Personalized Anti-Neoplastics for Gastro-Esophageal Adenocarcinoma'. Applying integral medium-throughput genomic and proteomic assays along with a practical biomarker assessment and treatment algorithm, 'PANGEA' attempts to address the problem of heterogeneity towards successful implementation of molecularly targeted therapies.
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Affiliation(s)
- Daniel V T Catenacci
- University of Chicago Medical Center, Department of Medicine, Section of Hematology & Oncology, 5841 S. Maryland Avenue, MC2115, Chicago, IL 60637, USA.
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13
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Abstract
We present direct experimental evidence that assembly of a single-stranded RNA virus occurs via a packaging signal-mediated mechanism. We show that the sequences of coat protein recognition motifs within multiple, dispersed, putative RNA packaging signals, as well as their relative spacing within a genomic fragment, act collectively to influence the fidelity and yield of capsid self-assembly in vitro. These experiments confirm that the selective advantages for viral yield and encapsidation specificity, predicted from previous modeling of packaging signal-mediated assembly, are found in Nature. Regions of the genome that act as packaging signals also function in translational and transcriptional enhancement, as well as directly coding for the coat protein, highlighting the density of encoded functions within the viral RNA. Assembly and gene expression are therefore direct molecular competitors for different functional folds of the same RNA sequence. The strongest packaging signal in the test fragment, encodes a region of the coat protein that undergoes a conformational change upon contact with packaging signals. A similar phenomenon occurs in other RNA viruses for which packaging signals are known. These contacts hint at an even deeper density of encoded functions in viral RNA, which if confirmed, would have profound consequences for the evolution of this class of pathogens.
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