25 research outputs found
Water-soluble Organometallic Analogues of Oxaliplatin with Cytotoxic and Anticlonogenic Activity
No full textPt prodrugs: We synthesized new cationic complexes [PtCl(η2-C2H4)(R,R-chxn)]Cl (1) and [PtCl(η2-C2H4) (S,S-chxn)]Cl (2), which are organometallic analogues of the drug oxaliplatin. Complexes 1 and 2 can be considered antitumor prodrugs, as we demonstrate that they can decompose to give the same metabolites as those of oxaliplatin
Wireframe DNA Origami for the Cellular Delivery of Platinum(II)-Based Drugs
No full textThe DNA origami method has revolutionized the field of DNA nanotechnology since its introduction. These nanostructures, with their customizable shape and size, addressability, nontoxicity, and capacity to carry bioactive molecules, are promising vehicles for therapeutic delivery. Different approaches have been developed for manipulating and folding DNA origami, resulting in compact lattice-based and wireframe designs. Platinum-based complexes, such as cisplatin and phenanthriplatin, have gained attention for their potential in cancer and antiviral treatments. Phenanthriplatin, in particular, has shown significant antitumor properties by binding to DNA at a single site and inhibiting transcription. The present work aims to study wireframe DNA origami nanostructures as possible carriers for platinum compounds in cancer therapy, employing both cisplatin and phenanthriplatin as model compounds. This research explores the assembly, platinum loading capacity, stability, and modulation of cytotoxicity in cancer cell lines. The findings indicate that nanomolar quantities of the ball-like origami nanostructure, obtained in the presence of phenanthriplatin and therefore loaded with that specific drug, reduced cell viability in MCF-7 (cisplatin-resistant breast adenocarcinoma cell line) to 33%, while being ineffective on the other tested cancer cell lines. The overall results provide valuable insights into using wireframe DNA origami as a highly stable possible carrier of Pt species for very long time-release purposes
Enzymatic Synthesis of Single-Stranded Clonal Pure Oligonucleotides
No full textSingle-stranded oligonucleotides, or oligodeoxyribonucleotides (ODNs), are very important in several fields of science such as molecular biology, diagnostics, nanotechnology, and gene therapy. They are usually chemically synthesized. Here we describe an enzymatic method which enables us to synthesize pure oligonucleotides which can be up to several hundred long bases
Possible incorporation of free N7-platinated guanines in DNA by DNA polymerases, relevance for the cisplatin mechanism of action.
No full textCisplatin, cis-diamminedichloroplatinum(II), is one of the most widely used anticancer drugs. The main cellular target of cisplatin is DNA, where the platinum atom is able to form covalent bonds with the N7 of purines. It is commonly accepted that there is a direct attack of cisplatin to DNA. But it should be noted that, inside cells, free purine bases, which can react with cisplatin, are also available. Free bases have many functional roles, not least the constitution of building blocks for the synthesis of new DNA and RNA molecules. For this reason, under physiological conditions, the erroneous insertion of platinated bases in the synthesized nucleic acids could compete with direct DNA/RNA platination. Moreover, due to the lower sterical hindrance offered by single nucleobases with respect to nucleic acids, platination is expected to be even easier for free purines with respect to DNA and RNA. We have recently shown, for the first time, that platinated DNA can be formed in vitro by Taq DNA polymerase promoted incorporation of platinated purines. Cytotoxicity tests with [Pt(dien)(N7-G)], dien = diethylenetriamine, G = 5’-dGTP, 5’-dGDP, 5’-GMP, 5’-dGMP, GUO, dGUO, complexes on HeLa cancer cells support this hypothesis being the relative cytotoxicity of [Pt(dien)(N7-G)] derivatives clearly related to their bioavailability. In vivo platination of free purines before their incorporation in nucleic acids opens therefore new perspectives in platinum based antitumour drugs, for both action mechanism better understanding and new molecular design
DNA Binding Studies and Cytotoxicity of a Dinuclear PtII Diazapyrenium- Based Metallo-supramolecular Rectangular Box
No full textThe interaction with native DNA of a 2,7-diazapyrenium-based ligand 1 and its PtII rectangular metallacycle 2 is explored through circular and linear dichroism and fluorescence spectroscopies. The metal-free ligand 1 binds through intercalation, with a binding constant of approximately 5*105m-1, whereas the metallacycle 2 binds and bends the DNA with a binding constant of 7*106m-1. PCR assays show that metallo-supramolecular box 2 interferes with DNA transactions in vitro whereas the intercalator 1 does not. The metallacycle is active against four human cancer cell lines, with IC50 values ranging between 3.1 and 19.2 mm and shows similar levels of efficacy, but a different spectrum of activity, to cisplatin
Experimental evidence that a DNA polymerase can incorporate N7-platinated guanines to give platinated DNA
No full textA model DNA polymerase and a model N7-metallated purine-triphosphate nucleotide, are used to show that metalated purines can be inserted into DNA during enzymatic in vitro synthetic process. Although several organic reporter groups covalently bonded to nucleotides are already widely used as experimental tools for nucleic acid modification, the possibility to obtain site specific metallation, mediated by DNA polymerase is here demonstrated for the first time
Noncovalent DNA-binding metallo-supramolecular cylinders prevent DNA transactions in vitro.
No full textInterplay of Three G‑Quadruplex Units in the <i>KIT</i> Promoter
No full textThe proto-oncogene KIT encodes for a tyrosine
kinase receptor, which is a clinically validated target for treating
gastrointestinal stromal tumors. The KIT promoter
contains a G-rich domain within a relatively long sequence potentially
able to form three adjacent G-quadruplex (G4) units, namely, K2, SP,
and K1. These G4 domains have been studied mainly as single quadruplex
units derived from short truncated sequences and are currently considered
promising targets for anticancer drugs, alternatively to the encoded
protein. Nevertheless, the information reported so far does not contemplate
the interplay between those neighboring G4s in the context of the
whole promoter, possibly thwarting drug-discovery efforts. Here we
report the structural and functional study of the KIT promoter core sequence, in both single- and double-stranded forms,
which includes all three predicted G4 units. By preventing the formation
of alternatively one or two G4 units and by combining biophysical
techniques and biological assays, we show for the first time that
these quadruplexes cannot be analyzed independently, but they are
correlated to each other. Our data suggest that, while K2 and K1 G-rich
sequences retain the ability to fold into parallel G4 motifs within
a long sequence, the SP G-rich domain contributes to G4 structure
only together with K2. Remarkably, we have found that, in the context
of a dynamic equilibrium between the three G4 units, the G4 formed
by K1 has the most significant influence on the structure stability
and on the biological role of the whole promoter
Development of nanoscale delivery systems for breast cancer treatment
No full textNanoparticle (NP) assisted diagnosis and drug delivery for antitumor applications have been widely investigated in the past few decades. To date, some of them have been approved for clinical applications and many more of them are under clinical trials. Although some progress has been achieved, it is still necessary to explore novel materials for antitumor applications. The work summarized in this thesis focused on organic NPs, and evaluated engineered polymer NPs and protein-lipid NPs as antitumor drug delivery systems in vitro. And a multifunctional fluorinated NP system was also assessed as theranostic (the combination of therapy and diagnosis) platform.In paper I, two types of 2,2 bis(hydroxymethyl) propionic acid (bis-MPA) based dendritic- linear (DL) polymers were synthesized. One type has the hyperbranched (HB) dendritic structure while the other has dendrons (perfectly branched structures). HBDL and DL materials were compared as drug delivery systems in respect to their synthesis difficulty, quality of micelle formation and efficiency in drug delivery. It was found that HBDL can be synthesized in large scales and drug loaded HBDL tended to have stronger efficacy compared to DL, therefore it is a promising alterative to DL in anticancer drug delivery.Further, in paper II, a detailed study regarding the uptake profile of a bis-MPA based hyperbranched copolymer micelle was conducted. The NP consisted of a Boltorn-H30 core (hyperbranched polyester) and PEG10k hydrophilic tails. It was found that the hyperbranched NP can be internalized into breast cancer cells via clathrin-dependent and macropinocytosis-mediated pathway through a time, concentration and energy dependent process.In paper III, fluorinated copolymers micelles were synthesized and evaluated as theranostic system, which has both diagnostic and therapeutic functions. The consequent micelles were able to load and release doxorubicin (DOX) and demonstrated similar efficacy compared to free (non- formulated) DOX. Also these NPs could generate a detectable signal for 19F-MRI in vitro.In paper IV, unimolecular NPs were developed from polyester based hyperbranched dendritic- linear polymers (HBDLPs). Such micelles were homogenous and did not have critical micelle concentration (CMC). And they were able to load DOX and delivery the drug into breast cancer cells. One HBDLP based NP containing a fluorinated polymer fragment was also synthesized to prove that these unimolecular systems are potentially useful as theranostic platforms.In paper V, histamine functionalized copolymer micelles were developed in order to introduce pH responsive property to NPs and achieve endo-lysosomal escape. These NPs were non-toxic and capable of loading and release DOX. Drug loaded NPs exhibited significant enhanced inhibition of mitochondria function in breast cancer cells during short periods (12 h) compared to free DOX. Although the expected pH responsive behaviour was not observed for the in vitro drug release model, NPs with histamine functionalization demonstrated partly endo-lysosomal escape property, in particular for those with 50% histamine modification. Intracellular tracking of NPs revealed that they could escape from endo-lysosomes and relocate DOX into mitochondria and the nuclei.In paper VI, lipoprotein like NP systems were developed by incorporating Saposin A, phospholipids and selected hydrophobic cargos. Such systems were shown to have promise as drug delivery platforms and to serve as NP based vaccine stabilizers.List of scientific papersI. Yvonne Hed, Yuning Zhang, Oliver C.J. Andren, Xianghui Zeng, Andreas M. Nyström, Michael Malkoch. Side-by-side comparison of dendritic-linear hybrids and their hyperbranched analogs as micellar carries of chemotherapeutics. Journal of Polymer Science part A: Polymer Chemistry, 2013, 51, 3992-3996. https://doi.org/10.1002/pola.26825 II. Xianghui Zeng, Yuning Zhang, Andreas M. Nyström. Endocytic uptake and intracellular trafficking of bis-MPA-based hyperbranched copolymer micelles in breast cancer cells. Biomacromolecules, 2012, 13, 3814-3822. https://doi.org/10.1021/bm301281k III. Christian Porsch, Yuning Zhang, Åsa Östlund, Peter Damberg, Cosimo Ducani, Eva Malmström, Andreas M. Nyström. In vitro evaluation of non- protein adsorbing breast cancer theranostics based on 19F-polymer containing nanoparticles. Particle & Particle Systems Characterization, 2013, 30, 381-390. https://doi.org/10.1002/ppsc.201300018 IV. Christian Porsch, Yuning Zhang, Cosimo Ducani, Francisco Vilaplana, Lars Nordstierna, Andreas M. Nyström, Eva Malmström. Toward unimolecular micelles with tunable dimensions using hyperbranced dendritic-linear polymers. Biomacromolecules, 2014, 15, 2235-2245. https://doi.org/10.1021/bm5003637 V. Yuning Zhang, Pontus Lundberg, Maren Diether, Christian Porsch, Caroline Janson, Nathaniel A. Lynd, Cosimo Ducani, Michael Malkoch, Eva Malström, Craig J. Hawker, Andreas M. Nyström. Histamine-functionalized copolymer micelles as a drug delivery system in 2D and 3D models of breast cancer. Journal of Materials Chemistry B, 2015, 3, 2472-2486. https://doi.org/10.1039/c4tb02051k VI. Jens Frauenfeld, Robin Löving, Yuning Zhang, Lin Zhu, Caroline Jegerschöld, Fatma Guettou, Per Moberg, Christian Löw, Andreas M. Nyström, Henrik Garoff, Pär Nordlund. A multi-functional nanoparticle system based on a small human protein. [Manuscript]</p
