Comparative Activity and Off-Target Effects in Cells of the CHK1 Inhibitors MK-8776, SRA737, and LY2606368

Fibroblast growth factor receptors (FGFRs) have become an attractive target in cancer research and therapy due to their implication in several cancers. Limitations of current treatment options require a need for additional, more specific and potent strategies to overcome cancers driven by FGFRs. Photochemical internalization (PCI) is a light-controlled method for cytosolic delivery of drugs that are entrapped in endosomes and lysosomes. We here evaluated the efficacy and selectivity of PCI of FGF2-saporin (FGF-SAP) in cells overexpressing FGFR1. FGF-SAP is a conjugate of FGF2 and the highly cytotoxic ribosome-inactivating protein (RIP) saporin, which is used as payload to eliminate cancer cells. Evaluation of the targeting effect of PCI of FGF-SAP was done by comparing the cytotoxic response in osteosarcoma cells with very low levels of FGFR1 (U2OS) to cells overexpressing FGFR1 (U2OS-R1). We demonstrate that PCI greatly enhances cytotoxicity of the drug showing efficient cell killing at pM concentrations of the drug in U2OS-R1 cells. However, U2OS cells were also sensitive to the toxin after PCI. Binding experiments using confocal microscopy and Western blotting techniques indicate that FGF-SAP is taken up by cells through heparan sulfate proteoglycans (HSPGs) in U2OS cells. We further show that the cytotoxicity of FGF-SAP in U2OS cells was reduced when cells were co-treated with heparin to compete out binding to HSPG, demonstrating that the cytotoxic effect was due to internalization by HSPGs. We conclude that to prevent off-target effects of FGF-based toxins, it will be necessary to circumvent binding to HSPGs, for example by mutating the binding site of FGF2 to HSPGs.

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A new plasmid-based microRNA inhibitor system that inhibits microRNA families in transgenic mice and cells: a potential new therapeutic reagent

Gene Therapy ◽

10.1038/gt.2016.22 ◽

2016 ◽

Vol 23 (6) ◽

pp. 527-542 ◽

Cited By ~ 18

Author(s):

H Cao ◽

W Yu ◽

X Li ◽

J Wang ◽

S Gao ◽

...

Keyword(s):

Transgenic Mice ◽

Family Members ◽

Stable Complex ◽

Developmental Defects ◽

Rna Molecules ◽

Inhibitor System ◽

Flanking Sequences ◽

Target Effects ◽

In Cells

Abstract Current tools for the inhibition of microRNA (miR) function are limited to modified antisense oligonucleotides, sponges and decoy RNA molecules and none have been used to understand miR function during development. CRISPR/Cas-mediated deletion of miR sequences within the genome requires multiple chromosomal deletions to remove all functional miR family members because of duplications. Here, we report a novel plasmid-based miR inhibitor system (PMIS) that expresses a new RNA molecule, which inhibits miR family members in cells and mice. The PMIS engineered RNA optimal secondary structure, flanking sequences and specific antisense miR oligonucleotide sequence bind the miR in a stable complex to inhibit miR activity. In cells, one PMIS can effectively inhibit miR family members that share the same seed sequence. The PMIS shows no off-target effects or toxicity and is highly specific for miRs sharing identical seed sequences. Transgenic mice expressing both PMIS-miR-17-18 and PMIS-miR-19-92 show similar phenotypes of miR-17-92-knockout mice. Interestingly, mice only expressing PMIS-miR-17-18 have developmental defects distinct from mice only expressing PMIS-miR-19-92 demonstrating usefulness of the PMIS system to dissect different functions of miRs within clusters. Different PMIS miR inhibitors can be linked together to knock down multiple miRs expressed from different chromosomes. Inhibition of the miR-17-92, miR-106a-363 and miR-106b-25 clusters reveals new mechanisms and developmental defects for these miRs. We report a new tool to dissect the role of miRs in development without genome editing, inhibit miR function in cells and as a potential new therapeutic reagent.

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Circular siRNAs for Reducing Off-Target Effects and Enhancing Long-Term Gene Silencing in Cells and Mice

Molecular Therapy — Nucleic Acids ◽

10.1016/j.omtn.2017.12.007 ◽

2018 ◽

Vol 10 ◽

pp. 237-244 ◽

Cited By ~ 13

Author(s):

Liangliang Zhang ◽

Duanwei Liang ◽

Changmai Chen ◽

Yuan Wang ◽

Gubu Amu ◽

...

Keyword(s):

Gene Silencing ◽

Target Effects ◽

In Cells

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Cytoplasmic Tubules in Cells Infected with Laryngotracheitis Virus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063792 ◽

1969 ◽

Vol 27 ◽

pp. 376-377

Author(s):

A. M. Watrach

Keyword(s):

Tissue Culture ◽

Small Proportion ◽

Chicken Embryo ◽

Culture Cells ◽

Tissue Culture Cells ◽

Morphologic Characteristics ◽

Infectious Laryngotracheitis ◽

Laryngotracheitis Virus ◽

In Cells

During a study of the development of infectious laryngotracheitis (LT) virus in tissue culture cells, unusual tubular formations were found in the cytoplasm of a small proportion of the affected cells. It is the purpose of this report to describe the morphologic characteristics of the tubules and to discuss their possible association with the development of virus.The source and maintenance of the strain of LT virus have been described. Prior to this study, the virus was passed several times in chicken embryo kidney (CEK) tissue culture cells.

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Effect of Some Metabolic Inhibitors on Vinblastine-Induced Ribosomal-Granular Material Complexes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100066796 ◽

1971 ◽

Vol 29 ◽

pp. 548-549

Author(s):

Awtar Krishan ◽

Dora Hsu

Keyword(s):

Granular Material ◽

Rna Synthesis ◽

Culture Medium ◽

Actinomycin D ◽

Metabolic Inhibitors ◽

Protein And Rna Synthesis ◽

Apparent Reduction ◽

Plant Alkaloids ◽

In Cells

Cells exposed to antitumor plant alkaloids, vinblastine and vincristine sulfate have large proteinacious crystals and complexes of ribosomes, helical polyribosomes and electron-dense granular material (ribosomal complexes) in their cytoplasm, Binding of H3-colchicine by the in vivo crystals shows that they contain microtubular proteins. Association of ribosomal complexes with the crystals suggests that these structures may be interrelated.In the present study cultured human leukemic lymphoblasts (CCRF-CEM), were incubated with protein and RNA-synthesis inhibitors, p. fluorophenylalanine, puromycin, cycloheximide or actinomycin-D before the addition of crystal-inducing doses of vinblastine to the culture medium. None of these compounds could completely prevent the formation of the ribosomal complexes or the crystals. However, in cells pre-incubated with puromycin, cycloheximide, or actinomycin-D, a reduction in the number and size of the ribosomal complexes was seen. Large helical polyribosomes were absent in the ribosomal complexes of cells treated with puromycin, while in cells exposed to cycloheximide, there was an apparent reduction in the number of ribosomes associated with the ribosomal complexes (Fig. 2).

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Detection of Nucleic Acids in Cells or Tissue Sections Using In situ Polymerase Chain Reaction (PCR)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100162545 ◽

1996 ◽

Vol 54 ◽

pp. 16-17

Author(s):

J. R. Hully ◽

K. R. Luehrsen ◽

K. Aoyagi ◽

C. Shoemaker ◽

R. Abramson

Keyword(s):

Nucleic Acids ◽

Viral Infections ◽

Anatomical Location ◽

Rt Pcr ◽

Reverse Transcription Pcr ◽

Cellular Source ◽

Gene Transcripts ◽

Initial Description ◽

In Cells

The development of PCR technology has greatly accelerated medical research at the genetic and molecular levels. Until recently, the inherent sensitivity of this technique has been limited to isolated preparations of nucleic acids which lack or at best have limited morphological information. With the obvious exception of cell lines, traditional PCR or reverse transcription-PCR (RT-PCR) cannot identify the cellular source of the amplified product. In contrast, in situ hybridization (ISH) by definition, defines the anatomical location of a gene and/or it’s product. However, this technique lacks the sensitivity of PCR and cannot routinely detect less than 10 to 20 copies per cell. Consequently, the localization of rare transcripts, latent viral infections, foreign or altered genes cannot be identified by this technique. In situ PCR or in situ RT-PCR is a combination of the two techniques, exploiting the sensitivity of PCR and the anatomical definition provided by ISH. Since it’s initial description considerable advances have been made in the application of in situ PCR, improvements in protocols, and the development of hardware dedicated to in situ PCR using conventional microscope slides. Our understanding of the importance of viral latency or viral burden in regards to HIV, HPV, and KSHV infections has benefited from this technique, enabling detection of single viral copies in cells or tissue otherwise thought to be normal. Clearly, this technique will be useful tool in pathobiology especially carcinogenesis, gene therapy and manipulations, the study of rare gene transcripts, and forensics.

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Absence of temporal ordering of apoptotic features in heat-shock treated leukemia and lymphoma cell lines

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166257 ◽

1996 ◽

Vol 54 ◽

pp. 758-759

Author(s):

D. W. Fairbain ◽

M.D. Standing ◽

K.L. O'Neill

Keyword(s):

Heat Shock ◽

Cell Lines ◽

Chromatin Condensation ◽

Membrane Integrity ◽

Resistant Cell ◽

Membrane Blebbing ◽

Late Loss ◽

Induced Apoptosis ◽

Dying Cells ◽

In Cells

Apoptosis is a genetically defined response to physiological stimuli that results in cellular suicide. Features common to apoptotic cells include chromatin condensation, oligonucleosomal DNA fragmentation, membrane blebbing, nuclear destruction, and late loss of ability to exclude vital dyes. These characteristics contrast markedly from pathological necrosis, in which membrane integrity loss is demonstrated early, and other features of apoptosis, which allow a non-inflammatory removal of dead and dying cells, are absent. Using heat shock-induced apoptosis as a model for examining stress response in cells, we undertook to categorize a variety of human leukemias and lymphomas with regard to their response to heat shock. We were also interested in determining whether a common temporal order was followed in cells dying by apoptosis. In addition, based on our previous results, we investigated whether increasing heat load resulted in increased apoptosis, with particular interest in relatively resistant cell lines, or whether the mode of death changed from apoptosis to necrosis.

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Umatilla Virus Association with Fibrils and Tubules in Cultured Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600002063 ◽

1980 ◽

Vol 38 ◽

pp. 476-477

Author(s):

Neil M. Foster ◽

Ruth D. Breckon

Keyword(s):

Bluetongue Virus ◽

Linear Array ◽

Cultured Cells ◽

Intimate Association ◽

Infected Cells ◽

Dark Staining ◽

In Cells

Macrotubules have been described1 in cells infected with Umatilla virus (UMAV), an orbivirus for which bluetongue virus (BTV) is the protype. Macrotubules, often in linear array, were observed in the cytoplasm and in intimate association with viroplasms of infected cells. Macrotubules had outside and inside diameters of 20 and 15 nm and many had dark-staining centers with diameters similar to the interiors of the tubules. UMAV was 60 nm and the RNA core was 30 nm in diameter. This report describes the association of UMAV with macrotubules and two types of microtubules.

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