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Quantitative in vivo whole genome motility screen reveals novel therapeutic targets to block cancer metastasis.
Stoletov K, Willetts L, Paproski RJ, Bond DJ, Raha S, Jovel J, Adam B, Robertson AE, Wong F, Woolner E, Sosnowski DL, Bismar TA, Wong GK, Zijlstra A, Lewis JD
(2018) Nat Commun 9: 2343
MeSH Terms: Animals, Cell Line, Tumor, Cell Movement, Chick Embryo, Collagen, Female, Gene Expression Profiling, Gene Expression Regulation, Neoplastic, Humans, Male, Mice, Mice, Nude, Mice, SCID, Neoplasm Invasiveness, Neoplasm Metastasis, Neoplasm Transplantation, Phenotype, Prostatic Neoplasms, RNA Interference, RNA, Small Interfering
Show Abstract · Added April 10, 2019
Metastasis is the most lethal aspect of cancer, yet current therapeutic strategies do not target its key rate-limiting steps. We have previously shown that the entry of cancer cells into the blood stream, or intravasation, is highly dependent upon in vivo cancer cell motility, making it an attractive therapeutic target. To systemically identify genes required for tumor cell motility in an in vivo tumor microenvironment, we established a novel quantitative in vivo screening platform based on intravital imaging of human cancer metastasis in ex ovo avian embryos. Utilizing this platform to screen a genome-wide shRNA library, we identified a panel of novel genes whose function is required for productive cancer cell motility in vivo, and whose expression is closely associated with metastatic risk in human cancers. The RNAi-mediated inhibition of these gene targets resulted in a nearly total (>99.5%) block of spontaneous cancer metastasis in vivo.
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MeSH Terms
Selective mTORC2 Inhibitor Therapeutically Blocks Breast Cancer Cell Growth and Survival.
Werfel TA, Wang S, Jackson MA, Kavanaugh TE, Joly MM, Lee LH, Hicks DJ, Sanchez V, Ericsson PG, Kilchrist KV, Dimobi SC, Sarett SM, Brantley-Sieders DM, Cook RS, Duvall CL
(2018) Cancer Res 78: 1845-1858
MeSH Terms: Animals, Antineoplastic Agents, Cell Proliferation, Cell Survival, Disease Models, Animal, Female, Humans, Lapatinib, Mechanistic Target of Rapamycin Complex 2, Mice, Mice, Inbred BALB C, Mice, Nude, Nanoparticles, Protein Kinase Inhibitors, RNA, Small Interfering, Rapamycin-Insensitive Companion of mTOR Protein, Receptor, ErbB-2, Triple Negative Breast Neoplasms, Xenograft Model Antitumor Assays
Show Abstract · Added March 14, 2018
Small-molecule inhibitors of the mTORC2 kinase (torkinibs) have shown efficacy in early clinical trials. However, the torkinibs under study also inhibit the other mTOR-containing complex mTORC1. While mTORC1/mTORC2 combined inhibition may be beneficial in cancer cells, recent reports describe compensatory cell survival upon mTORC1 inhibition due to loss of negative feedback on PI3K, increased autophagy, and increased macropinocytosis. Genetic models suggest that selective mTORC2 inhibition would be effective in breast cancers, but the lack of selective small-molecule inhibitors of mTORC2 have precluded testing of this hypothesis to date. Here we report the engineering of a nanoparticle-based RNAi therapeutic that can effectively silence the mTORC2 obligate cofactor Rictor. Nanoparticle-based Rictor ablation in HER2-amplified breast tumors was achieved following intratumoral and intravenous delivery, decreasing Akt phosphorylation and increasing tumor cell killing. Selective mTORC2 inhibition , combined with the HER2 inhibitor lapatinib, decreased the growth of HER2-amplified breast cancers to a greater extent than either agent alone, suggesting that mTORC2 promotes lapatinib resistance, but is overcome by mTORC2 inhibition. Importantly, selective mTORC2 inhibition was effective in a triple-negative breast cancer (TNBC) model, decreasing Akt phosphorylation and tumor growth, consistent with our findings that RICTOR mRNA correlates with worse outcome in patients with basal-like TNBC. Together, our results offer preclinical validation of a novel RNAi delivery platform for therapeutic gene ablation in breast cancer, and they show that mTORC2-selective targeting is feasible and efficacious in this disease setting. This study describes a nanomedicine to effectively inhibit the growth regulatory kinase mTORC2 in a preclinical model of breast cancer, targeting an important pathogenic enzyme in that setting that has been undruggable to date. .
©2018 American Association for Cancer Research.
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19 MeSH Terms
Heterozygous loss of TSC2 alters p53 signaling and human stem cell reprogramming.
Armstrong LC, Westlake G, Snow JP, Cawthon B, Armour E, Bowman AB, Ess KC
(2017) Hum Mol Genet 26: 4629-4641
MeSH Terms: Adolescent, Adult, Alleles, Cellular Reprogramming, Child, Child, Preschool, Female, Fibroblasts, Genes, p53, Heterozygote, Humans, Induced Pluripotent Stem Cells, Infant, Loss of Heterozygosity, Male, Mutation, RNA, Small Interfering, Signal Transduction, TOR Serine-Threonine Kinases, Tuberous Sclerosis, Tuberous Sclerosis Complex 1 Protein, Tuberous Sclerosis Complex 2 Protein, Tumor Suppressor Protein p53, Tumor Suppressor Proteins
Show Abstract · Added April 11, 2018
Tuberous sclerosis complex (TSC) is a pediatric disorder of dysregulated growth and differentiation caused by loss of function mutations in either the TSC1 or TSC2 genes, which regulate mTOR kinase activity. To study aberrations of early development in TSC, we generated induced pluripotent stem cells using dermal fibroblasts obtained from patients with TSC. During validation, we found that stem cells generated from TSC patients had a very high rate of integration of the reprogramming plasmid containing a shRNA against TP53. We also found that loss of one allele of TSC2 in human fibroblasts is sufficient to increase p53 levels and impair stem cell reprogramming. Increased p53 was also observed in TSC2 heterozygous and homozygous mutant human stem cells, suggesting that the interactions between TSC2 and p53 are consistent across cell types and gene dosage. These results support important contributions of TSC2 heterozygous and homozygous mutant cells to the pathogenesis of TSC and the important role of p53 during reprogramming.
© The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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24 MeSH Terms
Lipophilic siRNA targets albumin in situ and promotes bioavailability, tumor penetration, and carrier-free gene silencing.
Sarett SM, Werfel TA, Lee L, Jackson MA, Kilchrist KV, Brantley-Sieders D, Duvall CL
(2017) Proc Natl Acad Sci U S A 114: E6490-E6497
MeSH Terms: Cell Line, Tumor, Gene Silencing, Humans, Neoplasms, RNA, Small Interfering, Serum Albumin, Human
Show Abstract · Added March 14, 2018
Clinical translation of therapies based on small interfering RNA (siRNA) is hampered by siRNA's comprehensively poor pharmacokinetic properties, which necessitate molecule modifications and complex delivery strategies. We sought an alternative approach to commonly used nanoparticle carriers by leveraging the long-lived endogenous serum protein albumin as an siRNA carrier. We synthesized siRNA conjugated to a diacyl lipid moiety (siRNA-L), which rapidly binds albumin in situ. siRNA-L, in comparison with unmodified siRNA, exhibited a 5.7-fold increase in circulation half-life, an 8.6-fold increase in bioavailability, and reduced renal accumulation. Benchmarked against leading commercial siRNA nanocarrier in vivo jetPEI, siRNA-L achieved 19-fold greater tumor accumulation and 46-fold increase in per-tumor-cell uptake in a mouse orthotopic model of human triple-negative breast cancer. siRNA-L penetrated tumor tissue rapidly and homogeneously; 30 min after i.v. injection, siRNA-L achieved uptake in 99% of tumor cells, compared with 60% for jetPEI. Remarkably, siRNA-L achieved a tumor:liver accumulation ratio >40:1 vs. <3:1 for jetPEI. The improved pharmacokinetic properties of siRNA-L facilitated significant tumor gene silencing for 7 d after two i.v. doses. Proof-of-concept was extended to a patient-derived xenograft model, in which jetPEI tumor accumulation was reduced fourfold relative to the same formulation in the orthotopic model. The siRNA-L tumor accumulation diminished only twofold, suggesting that the superior tumor distribution of the conjugate over nanoparticles will be accentuated in clinical situations. These data reveal the immense promise of in situ albumin targeting for development of translational, carrier-free RNAi-based cancer therapies.
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6 MeSH Terms
Zwitterionic Nanocarrier Surface Chemistry Improves siRNA Tumor Delivery and Silencing Activity Relative to Polyethylene Glycol.
Jackson MA, Werfel TA, Curvino EJ, Yu F, Kavanaugh TE, Sarett SM, Dockery MD, Kilchrist KV, Jackson AN, Giorgio TD, Duvall CL
(2017) ACS Nano 11: 5680-5696
MeSH Terms: Animals, Cell Line, Tumor, Drug Carriers, Female, Humans, Male, Mice, Nude, Nanostructures, Neoplasms, Phosphorylcholine, Polyethylene Glycols, Polymers, RNA, Small Interfering, RNAi Therapeutics, Surface Properties
Show Abstract · Added March 14, 2018
Although siRNA-based nanomedicines hold promise for cancer treatment, conventional siRNA-polymer complex (polyplex) nanocarrier systems have poor pharmacokinetics following intravenous delivery, hindering tumor accumulation. Here, we determined the impact of surface chemistry on the in vivo pharmacokinetics and tumor delivery of siRNA polyplexes. A library of diblock polymers was synthesized, all containing the same pH-responsive, endosomolytic polyplex core-forming block but different corona blocks: 5 kDa (benchmark) and 20 kDa linear polyethylene glycol (PEG), 10 kDa and 20 kDa brush-like poly(oligo ethylene glycol), and 10 kDa and 20 kDa zwitterionic phosphorylcholine-based polymers (PMPC). In vitro, it was found that 20 kDa PEG and 20 kDa PMPC had the highest stability in the presence of salt or heparin and were the most effective at blocking protein adsorption. Following intravenous delivery, 20 kDa PEG and PMPC coronas both extended circulation half-lives 5-fold compared to 5 kDa PEG. However, in mouse orthotopic xenograft tumors, zwitterionic PMPC-based polyplexes showed highest in vivo luciferase silencing (>75% knockdown for 10 days with single IV 1 mg/kg dose) and 3-fold higher average tumor cell uptake than 5 kDa PEG polyplexes (20 kDa PEG polyplexes were only 2-fold higher than 5 kDa PEG). These results show that high molecular weight zwitterionic polyplex coronas significantly enhance siRNA polyplex pharmacokinetics without sacrificing polyplex uptake and bioactivity within tumors when compared to traditional PEG architectures.
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15 MeSH Terms
Combinatorial optimization of PEG architecture and hydrophobic content improves ternary siRNA polyplex stability, pharmacokinetics, and potency in vivo.
Werfel TA, Jackson MA, Kavanaugh TE, Kirkbride KC, Miteva M, Giorgio TD, Duvall C
(2017) J Control Release 255: 12-26
MeSH Terms: Animals, Cell Line, Cell Line, Tumor, Female, Humans, Hydrophobic and Hydrophilic Interactions, Luciferases, Methacrylates, Mice, Mice, Nude, Polyethylene Glycols, RNA, Small Interfering, Tissue Distribution
Show Abstract · Added March 14, 2018
A rationally-designed library of ternary siRNA polyplexes was developed and screened for gene silencing efficacy in vitro and in vivo with the goal of overcoming both cell-level and systemic delivery barriers. [2-(dimethylamino)ethyl methacrylate] (DMAEMA) was homopolymerized or copolymerized (50mol% each) with butyl methacrylate (BMA) from a reversible addition - fragmentation chain transfer (RAFT) chain transfer agent, with and without pre-conjugation to polyethylene glycol (PEG). Both single block polymers were tested as core-forming units, and both PEGylated, diblock polymers were screened as corona-forming units. Ternary siRNA polyplexes were assembled with varied amounts and ratios of core-forming polymers to PEGylated corona-forming polymers. The impact of polymer composition/ratio, hydrophobe (BMA) placement, and surface PEGylation density was correlated to important outcomes such as polyplex size, stability, pH-dependent membrane disruptive activity, biocompatibility, and gene silencing efficiency. The lead formulation, DB4-PDB12, was optimally PEGylated not only to ensure colloidal stability (no change in size by DLS between 0 and 24h) and neutral surface charge (0.139mV) but also to maintain higher cell uptake (>90% positive cells) than the most densely PEGylated particles. The DB4-PDB12 polyplexes also incorporated BMA in both the polyplex core- and corona-forming polymers, resulting in robust endosomolysis and in vitro siRNA silencing (~85% protein level knockdown) of the model gene luciferase across multiple cell types. Further, the DB4-PDB12 polyplexes exhibited greater stability, increased blood circulation time, reduced renal clearance, increased tumor biodistribution, and greater silencing of luciferase compared to our previously-optimized, binary parent formulation following intravenous (i.v.) delivery. This polyplex library approach enabled concomitant optimization of the composition and ratio of core- and corona-forming polymers (indirectly tuning PEGylation density) and identification of a ternary nanomedicine optimized to overcome important siRNA delivery barriers in vitro and in vivo.
Copyright © 2017 Elsevier B.V. All rights reserved.
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13 MeSH Terms
LRRC8A channels support TNFα-induced superoxide production by Nox1 which is required for receptor endocytosis.
Choi H, Ettinger N, Rohrbough J, Dikalova A, Nguyen HN, Lamb FS
(2016) Free Radic Biol Med 101: 413-423
MeSH Terms: Cell Line, Cyclopentanes, Endocytosis, Gene Expression Regulation, HEK293 Cells, Humans, Indans, JNK Mitogen-Activated Protein Kinases, Membrane Proteins, Myocytes, Smooth Muscle, NADPH Oxidase 1, NF-kappa B, Phosphorylation, Protein Subunits, RNA, Small Interfering, Receptors, Tumor Necrosis Factor, Type I, Signal Transduction, Superoxide Dismutase, Superoxides, Tumor Necrosis Factor-alpha, Vascular Cell Adhesion Molecule-1
Show Abstract · Added March 26, 2019
Leucine Rich Repeat Containing 8A (LRRC8A) is a required component of volume-regulated anion channels (VRACs). In vascular smooth muscle cells, tumor necrosis factor-α (TNFα) activates VRAC via type 1 TNFα receptors (TNFR1), and this requires superoxide (O) production by NADPH oxidase 1 (Nox1). VRAC inhibitors suppress the inflammatory response to TNFα by an unknown mechanism. We hypothesized that LRRC8A directly supports Nox1 activity, providing a link between VRAC current and inflammatory signaling. VRAC inhibition by 4-(2-butyl-6,7-dichlor-2-cyclopentylindan-1-on-5-yl) oxobutyric acid (DCPIB) impaired NF-κB activation by TNFα. LRRC8A siRNA reduced the magnitude of VRAC and inhibited TNFα-induced NF-κB activation, iNOS and VCAM expression, and proliferation of VSMCs. Signaling steps disrupted by both siLRRC8A and DCPIB included; extracellular O production by Nox1, c-Jun N-terminal kinase (JNK) phosphorylation and endocytosis of TNFR1. Extracellular superoxide dismutase, but not catalase, selectively inhibited TNFR1 endocytosis and JNK phosphorylation. Thus, O is the critical extracellular oxidant for TNFR signal transduction. Reducing JNK expression (siJNK) increased extracellular O suggesting that JNK provides important negative feedback regulation to Nox1 at the plasma membrane. LRRC8A co-localized by immunostaining, and co-immunoprecipitated with, both Nox1 and its p22phox subunit. LRRC8A is a component of the Nox1 signaling complex. It is required for extracellular O production, which is in turn essential for TNFR1 endocytosis. These data are the first to provide a molecular mechanism for the potent anti-proliferative and anti-inflammatory effects of VRAC inhibition.
Copyright © 2016 Elsevier Inc. All rights reserved.
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Local Delivery of PHD2 siRNA from ROS-Degradable Scaffolds to Promote Diabetic Wound Healing.
Martin JR, Nelson CE, Gupta MK, Yu F, Sarett SM, Hocking KM, Pollins AC, Nanney LB, Davidson JM, Guelcher SA, Duvall CL
(2016) Adv Healthc Mater 5: 2751-2757
MeSH Terms: Animals, Cell Proliferation, Diabetes Mellitus, Male, Neovascularization, Physiologic, Procollagen-Proline Dioxygenase, RNA, Small Interfering, Rats, Rats, Sprague-Dawley, Reactive Oxygen Species, Tissue Engineering, Tissue Scaffolds, Wound Healing
Show Abstract · Added March 14, 2018
Small interfering RNA (siRNA) delivered from reactive oxygen species-degradable tissue engineering scaffolds promotes diabetic wound healing in rats. Porous poly(thioketal-urethane) scaffolds implanted in diabetic wounds locally deliver siRNA that inhibits the expression of prolyl hydroxylase domain protein 2, thereby increasing the expression of progrowth genes and increasing vasculature, proliferating cells, and tissue development in diabetic wounds.
© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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13 MeSH Terms
Cortactin promotes exosome secretion by controlling branched actin dynamics.
Sinha S, Hoshino D, Hong NH, Kirkbride KC, Grega-Larson NE, Seiki M, Tyska MJ, Weaver AM
(2016) J Cell Biol 214: 197-213
MeSH Terms: Actin-Related Protein 2-3 Complex, Actins, Biological Transport, Cell Line, Tumor, Cell Membrane, Cortactin, Exosomes, Humans, Microfilament Proteins, Models, Biological, Molecular Docking Simulation, Multivesicular Bodies, Phenotype, Protein Binding, Pseudopodia, RNA, Small Interfering, Tetraspanin 30, rab GTP-Binding Proteins
Show Abstract · Added April 7, 2017
Exosomes are extracellular vesicles that influence cellular behavior and enhance cancer aggressiveness by carrying bioactive molecules. The mechanisms that regulate exosome secretion are poorly understood. Here, we show that the actin cytoskeletal regulatory protein cortactin promotes exosome secretion. Knockdown or overexpression of cortactin in cancer cells leads to a respective decrease or increase in exosome secretion, without altering exosome cargo content. Live-cell imaging revealed that cortactin controls both trafficking and plasma membrane docking of multivesicular late endosomes (MVEs). Regulation of exosome secretion by cortactin requires binding to the branched actin nucleating Arp2/3 complex and to actin filaments. Furthermore, cortactin, Rab27a, and coronin 1b coordinately control stability of cortical actin MVE docking sites and exosome secretion. Functionally, the addition of purified exosomes to cortactin-knockdown cells rescued defects of those cells in serum-independent growth and invasion. These data suggest a model in which cortactin promotes exosome secretion by stabilizing cortical actin-rich MVE docking sites.
© 2016 Sinha et al.
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18 MeSH Terms
An LGG-derived protein promotes IgA production through upregulation of APRIL expression in intestinal epithelial cells.
Wang Y, Liu L, Moore DJ, Shen X, Peek RM, Acra SA, Li H, Ren X, Polk DB, Yan F
(2017) Mucosal Immunol 10: 373-384
MeSH Terms: Animals, Antibody Formation, B-Lymphocytes, Bacterial Proteins, Cells, Cultured, Epithelial Cells, ErbB Receptors, Immunoglobulin A, Intestine, Small, Lactobacillus rhamnosus, Mice, Mice, Inbred C57BL, Mice, Knockout, Mice, Transgenic, RNA, Small Interfering, Transcriptional Activation, Tumor Necrosis Factor Ligand Superfamily Member 13, Up-Regulation
Show Abstract · Added June 30, 2016
p40, a Lactobacillus rhamnosus GG (LGG)-derived protein, transactivates epidermal growth factor receptor (EGFR) in intestinal epithelial cells, leading to amelioration of intestinal injury and inflammation. To elucidate mechanisms by which p40 regulates mucosal immunity to prevent inflammation, this study aimed to determine the effects and mechanisms of p40 on regulation of a proliferation-inducing ligand (APRIL) expression in intestinal epithelial cells for promoting immunoglobulin A (IgA) production. p40 upregulated April gene expression and protein production in mouse small intestine epithelial (MSIE) cells, which were inhibited by blocking EGFR expression and kinase activity. Enteroids from Egfr, but not Egfr-Vil-Cre mice with EGFR specifically deleted in intestinal epithelial cells, exhibited increased April gene expression by p40 treatment. p40-conditioned media from MSIE cells increased B-cell class switching to IgA cells and IgA production, which was suppressed by APRIL receptor-neutralizing antibodies. Treatment of B cells with p40 did not show any effects on IgA production. p40 treatment increased April gene expression and protein production in small intestinal epithelial cells, fecal IgA levels, IgAB220, IgACD19, and IgA plasma cells in lamina propria of Egfr, but not of Egfr-Vil-Cre, mice. Thus p40 upregulates EGFR-dependent APRIL production in intestinal epithelial cells, which may contribute to promoting IgA production.
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18 MeSH Terms