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- Höök, Fredrik, 1966, et al.
(author)
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Characterization of PNA and DNA Immobilization and Subsequent Hybridization with DNA Using Acoustic-Shear-Wave Attenuation Measurements
- 2001
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In: Langmuir. - : American Chemical Society (ACS). - 1520-5827 .- 0743-7463. ; 17:26, s. 8305-8312
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Journal article (peer-reviewed)abstract
- We report here how the quartz crystal microbalance with dissipation monitoring (QCM-D) technique, simultaneously measuring changes in the induced energy dissipation, D (cf. viscoelastic properties), and the frequency, f (cf. coupled mass), can be used to characterize the bound state of single-stranded peptide nucleic acid (PNA) and deoxyribose nucleic acid (DNA) in relation to their ability to function as selective probe(s) for fully complementary and single-mismatch DNA. The possibility to use the QCM-D technique for detection of binding kinetics and structural differences in the formed duplexes is also presented. We found that thiol-PNA and thiol-DNA attached via a sulfur group directly on a bare-gold surface are less efficient as probes for DNA than are biotin-PNA and biotin-DNA, coupled on top of a two-dimensional (2-D) arrangement of streptavidin, formed on a biotinylated phospholipid bilayer on a SiO2 surface. The fully complementary and singly mismatched DNA oligomers hybridize with the immobilized PNA and DNA. A single mismatch is discriminated via a significant difference in the binding and dissociation kinetics, demonstrating a high selectivity and thus successful immobilization of functional single strands. The observed ratios between hybridization-induced energy dissipation (DeltaD) and the frequency shift (Deltaf) made it possible to discriminate thiol-PNA directly attached to a gold surface from biotin-PNA coupled to the streptavidin 2-D arrangement, where the former were shown to be inefficient for detecting subsequent hybridization. Structural differences of the immobilized layers composed of biotin-PNA-DNA and biotin-DNA-DNA were clearly reflected by the DeltaD and Deltaf response.
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| 2. |
- Ray, Arghya, et al.
(author)
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A novel alkylating agent Melflufen induces irreversible DNA damage and cytotoxicity in multiple myeloma cells
- 2016
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In: British Journal of Haematology. - : Wiley. - 0007-1048 .- 1365-2141. ; 174:3, s. 397-409
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Journal article (peer-reviewed)abstract
- Our prior study utilized both invitro and invivo multiple myeloma (MM) xenograft models to show that a novel alkylator melphalan-flufenamide (Melflufen) is a more potent anti-MM agent than melphalan and overcomes conventional drug resistance. Here we examined whether this potent anti-MM activity of melflufen versus melphalan is due to their differential effect on DNA damage and repair signalling pathways via -H2AX/ATR/CHK1/Ku80. Melflufen-induced apoptosis was associated with dose- and time-dependent rapid phosphorylation of -H2AX. Melflufen induces -H2AX, ATR, and CHK1 as early as after 2h exposure in both melphalan-sensitive and -resistant cells. However, melphalan induces -H2AX in melphalan-sensitive cells at 6h and 24h; no -H2AX induction was observed in melphalan-resistant cells even after 24h exposure. Similar kinetics was observed for ATR and CHK1 in meflufen- versus melphalan-treated cells. DNA repair is linked to melphalan-resistance; and importantly, we found that melphalan, but not melflufen, upregulates Ku80 that repairs DNA double-strand breaks. Washout experiments showed that a brief (2h) exposure of MM cells to melflufen is sufficient to initiate an irreversible DNA damage and cytotoxicity. Our data therefore suggest that melflufen triggers a rapid, robust, and an irreversible DNA damage which may account for its ability to overcome melphalan-resistance in MM cells.
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| 3. |
- Ray, Arghya, et al.
(author)
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Peptide nucleic acid (PNA): its medical and biotechnical applications and promise for the future
- 2000
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In: FASEB Journal. - 1530-6860 .- 0892-6638. ; 14:9, s. 1041-1060
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Journal article (peer-reviewed)abstract
- Synthetic molecules that can bind with high sequence specificity to a chosen target in a gene sequence are of major interest in medicinal and biotechnological contexts. They show promise for the development of gene therapeutic agents, diagnostic devices for genetic analysis, and as molecular tools for nucleic acid manipulations. Peptide nucleic acid (PNA) is a nucleic acid analog in which the sugar phosphate backbone of natural nucleic acid has been replaced by a synthetic peptide backbone usually formed from N-(2-amino-ethyl)-glycine units, resulting in an achiral and uncharged mimic. It is chemically stable and resistant to hydrolytic (enzymatic) cleavage and thus not expected to be degraded inside a living cell. PNA is capable of sequence-specific recognition of DNA and RNA obeying the Watson-Crick hydrogen bonding scheme, and the hybrid complexes exhibit extraordinary thermal stability and unique ionic strength effects. It may also recognize duplex homopurine sequences of DNA to which it binds by strand invasion, forming a stable PNA-DNA-PNA tripler with a looped-out DNA strand. Since its discovery, PNA has attracted major attention at the interface of chemistry and biology because of its interesting chemical, physical, and biological properties and its potential to act as an active component for diagnostic as well as pharmaceutical applications. In vitro studies indicate that PNA could inhibit both transcription and translation of genes to which it has been targeted, which holds promise for its use for antigene and antisense therapy. However, as with other high molecular mass drugs, the delivery of PNA, involving passage through the cell membrane, appears to be a general problem.-Ray, A., Norden, B. Peptide nucleic acid (PNA): its medical and biotechnical applications and promise for the future.
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