scholarly journals N-Heterocyclic Carbene-Platinum Complexes Featuring an Anthracenyl Moiety: Anti-Cancer Activity and DNA Interaction

2019 ◽  
Vol 20 (17) ◽  
pp. 4198 ◽  
Author(s):  
Sébastien Harlepp ◽  
Edith Chardon ◽  
Mathilde Bouché ◽  
Georges Dahm ◽  
Mounir Maaloum ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Platinum Complex ◽  
Platinum Complexes ◽  
Dna Interaction ◽  
Contour Length ◽  
State Behavior ◽  
Force Microscopy ◽  
Pt Complex ◽  
Dna Strands

A platinum (II) complex stabilized by a pyridine and an N-heterocyclic carbene ligand featuring an anthracenyl moiety was prepared. The compound was fully characterized and its molecular structure was determined by single-crystal X-ray diffraction. The compound demonstrated high in vitro antiproliferative activities against cancer cell lines with IC50 ranging from 10 to 80 nM. The presence of the anthracenyl moiety on the N-heterocyclic carbene (NHC) Pt complex was used as a luminescent tag to probe the metal interaction with the nucleobases of the DNA through a pyridine-nucleobase ligand exchange. Such interaction of the platinum complex with DNA was corroborated by optical tweezers techniques and liquid phase atomic force microscopy (AFM). The results revealed a two-state interaction between the platinum complex and the DNA strands. This two-state behavior was quantified from the different experiments due to contour length variations. At 24 h incubation, the stretching curves revealed multiple structural breakages, and AFM imaging revealed a highly compact and dense structure of platinum complexes bridging the DNA strands.

scholarly journals N-Heterocyclic Carbene-Platinum Complexes Featuring an Anthracenyl Moiety: Anti-Cancer Activity and DNA Interaction.

2019 ◽  
Author(s):  
Sébastien Harlepp ◽  
Edith Chardon ◽  
Mathilde Bouché ◽  
Georges Dahm ◽  
Mounir Maaloum ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Platinum Complex ◽  
Platinum Complexes ◽  
Dna Interaction ◽  
Contour Length ◽  
X Ray Diffraction ◽  
Pt Complex ◽  
Dna Strands ◽  
State Behaviour

A platinum (II) complex stabilized by a pyridine and a N-heterocyclic carbene ligand featuring an anthracenyl moiety was prepared. The compound was fully characterized and its molecular structure was determined by single-crystal X-ray diffraction. The compound demonstrated high in vitro antiproliferative activities against cancer cell lines with IC50 ranging from 10 to 80 nM. The presence of the anthracenyl moiety on the NHC Pt complex was used as a luminescent tag to probe the metal interaction with the nucleobases of the DNA through a pyridine-nucleobase ligand exchange. Such interaction of the platinum complex with DNA was corroborated by optical tweezers techniques and liquid phase AFM microscopy. The results revealed a two-state interaction between the platinum complex and the DNA strands. This two-state behaviour was quantified from the different experiments due to contour length variations. At 24h incubation, the stretching curves revealed multiple structural breakages, and AFM imaging revealed a highly compact and dense structure of platinum complexes bridging the DNA strands.

Platinum complexes with imino ethers or cyclic ligands mimicking imino ethers: synthesis, in vitro antitumour activity, and DNA interaction properties

2004 ◽  
Vol 9 (6) ◽  
pp. 768-780 ◽  
Author(s):  
Francesco P. Intini ◽  
Angelina Boccarelli ◽  
Valentina C. Francia ◽  
Concetta Pacifico ◽  
Maria F. Sivo ◽  
...  
Keyword(s):  
Antitumour Activity ◽  
Platinum Complexes ◽  
Dna Interaction

scholarly journals Human Holliday junction resolvase GEN1 uses a chromodomain for efficient DNA recognition and cleavage

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Shun-Hsiao Lee ◽  
Lissa Nicola Princz ◽  
Maren Felizitas Klügel ◽  
Bianca Habermann ◽  
Boris Pfander ◽  
...  
Keyword(s):  
Dna Recognition ◽  
Dna Interaction ◽  
Holliday Junctions ◽  
Genome Integrity ◽  
Chromatin Remodelers ◽  
Activity Structure ◽  
Dna Strands ◽  
Holliday Junction Resolvase

Holliday junctions (HJs) are key DNA intermediates in homologous recombination. They link homologous DNA strands and have to be faithfully removed for proper DNA segregation and genome integrity. Here, we present the crystal structure of human HJ resolvase GEN1 complexed with DNA at 3.0 Å resolution. The GEN1 core is similar to other Rad2/XPG nucleases. However, unlike other members of the superfamily, GEN1 contains a chromodomain as an additional DNA interaction site. Chromodomains are known for their chromatin-targeting function in chromatin remodelers and histone(de)acetylases but they have not previously been found in nucleases. The GEN1 chromodomain directly contacts DNA and its truncation severely hampers GEN1’s catalytic activity. Structure-guided mutations in vitro and in vivo in yeast validated our mechanistic findings. Our study provides the missing structure in the Rad2/XPG family and insights how a well-conserved nuclease core acquires versatility in recognizing diverse substrates for DNA repair and maintenance.

TRANSITION METAL ION COMPLEXES AS POTENTIAL ANTITUMOR AGENTS

2021 ◽  
Author(s):  
Biljana Petrović ◽  
Keyword(s):  
Antitumor Activity ◽  
Transition Metal ◽  
Metal Ion ◽  
Antitumor Agents ◽  
Platinum Complex ◽  
Platinum Complexes ◽  
Metal Ion Complexes ◽  
Transition Metal Ion ◽  
Potential Antitumor

Discovery of the antitumor activity of platinum complex, cisplatin, cis-Pt(NH3)2Cl2, and later carboplatin and oxaliplatin, led to the intensive investigation of the potential antitumor activity of the huge number of platinum complexes. Furthermore, it is well-known that platinum complexes express toxicity, numerous side effects and resistance, so the scientists make a lot of efforts to synthetize, beside Pt(II) and Pt(IV), other non-platinum compounds with potential antitumor activity, such as Pd(II), Ru(II/III) and Au(III) complexes. The goal of this study is to summarize the results of the investigation of the interactions between some mononuclear, homo- and hetero-polynuclear Pt(II), Pd(II), Ru(II/III) and Au(III) complexes with different sulfur- and nitrogen-donor biologically relevant nucleophiles. Among mononuclear complexes, the compounds with aromatic terpy (tepyridine) or bpma (bis-(2- pyridylmethyl)amine) and aliphatic dien (diethylentriamine) nitrogen-containing inert ligands were studied. Different homo- and hetero-polynuclear complexes with pz (pyrazine) or 4,4’-bipy (4,4’- bipyridine) as bridging and mostly en (ethylenediamine), bipy (2,2’-bipyridine) and dach (trans-1,2- diaminocyclohexane) as inert ligands were studied as well. The research was focused on the connection between the structure and the mechanisms of interactions with different biomolecules, such as L- cysteine (L-Cys), L-methionine (L-Met), tripeptide glutathione (GSH), guanosine-5’-monophosphate (5’-GMP), DNA and bovine serum albumin (BSA). Some of these complexes were selected for in vitro studies of the cytotoxicity on different tumor cell lines. Observed results contribute a lot as a guidance for the future design and determination of the structure-activity relationship (SAR) of different transition metal ion complexes.

Efficacy of newly developed platinum complexes against osteosarcoma, bone-targeting platinum, and proteasome inhibitory platinum.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 10075-10075
Author(s):  
Kentaro Igarashi ◽  
Norio Yamamoto ◽  
Toshiharu Shirai ◽  
Katsuhiro Hayashi ◽  
Hideji Nishida ◽  
...  
Keyword(s):  
Side Effects ◽  
Platinum Complex ◽  
Annexin V ◽  
Platinum Complexes ◽  
Clinical Results ◽  
Platinum Compound ◽  
Platinum Compounds ◽  
Ic50 Value

10075 Background: Cisplatin is one of the most effective anti-cancer drugs available for the treatment of human solid tumors including osteosarcoma. As we had already reported, we have utilized caffeine in our chemotherapy protocol. And we achieved excellent clinical results. But effectiveness of cisplatin has been limited by side effects, and resistance. Here we developed two novel platinum compounds. 3Pt is trinuclear platinum complex bearing geminal bisphosphonate moieties, 1Pt is mononuclear platinum complex which has proteasome inhibitory activity. We performed comparative studies of our novel platinum compounds with osteosarcoma. Methods: Two novel platinum complexes were synthesized by Prof. Odani at school of pharmaceutical sciences of our university and cisplatin and caffeine were obtained from constructor. Three cell lines (MG63, 143B, and LM8) were used. Cell survival after a 72 hrs exposure to these compounds was assessed by WST-8 assay, and IC50 value was calculated for each compound. Apoptosis was assessed by DNA fragmentation and Annexin V-FITC/propidium iodine assay. Results: Each compound strongly caused concentration-dependent cytocidal effect. IC50 value of trinuclear compound is superior to cisplatin, and both complexes showed caffeine potentiation. Apoptosis induction and acetylation of histon H2AX were observed. In vivo, 1Pt showed almost same, 3Pt showed strong antitumor effect compared to cisplatin. Conclusions: Two novel platinum compounds that we developed showed strong ant-tumor effect in osteosarcoma in vitro and in vivo. As bisphosphonate has high affinity to calcium ions, 3Pt targets bone tissue and expected to reduce side effects at extraskeletal sites and to overcome the drug resistance. Proteasome inhibitory platinum compound has never been reported before, we will investigate its anti-tumor mechanism precisely.

scholarly journals Single-Molecule DNA Stretching Using Optical Tweezers

2009 ◽  
Vol 17 (1) ◽  
pp. 42-43 ◽  
Author(s):  
Joost van Mameren ◽  
Anna Wozniak ◽  
Sid Ragona
Keyword(s):  
Optical Tweezers ◽  
Single Molecule ◽  
Precise Measurement ◽  
Dna Interaction ◽  
Dna Stretching ◽  
Force Microscopy ◽  
Single Dna Molecules ◽  
Atomic Force ◽  
Protein Fibers ◽  
Individual Motor

The advent of techniques to mechanically manipulate single (bio)molecules has sparked large efforts to precisely study the mechanical and elastic properties of proteins, protein fibers, DNA, RNA, etc. Two widely used techniques in this area are atomic force microscopy (AFM) and optical tweezers. Optical tweezers complement AFM at the lower end of the force regime: forces of typically a few hundred picoNewtons down to fractions of a picoNewton can be assessed using optical tweezers. This has allowed for, among other things, the precise measurement of forces and displacements exerted by individual motor proteins. In this report, we focus on the use of optical tweezers for force spectroscopy on single DNA molecules, and on the range of applications that this technique offers to learn not only about DNA itself, but also about the mechanics and thermodynamics of protein-DNA interaction.

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

Targeting Breast Cancer Cells with G4 PAMAM Dendrimers and Valproic Acid Derivative Complexes

2020 ◽  
Vol 20 (15) ◽  
pp. 1857-1872
Author(s):  
Alberto M. Muñoz ◽  
Manuel J. Fragoso-Vázquez ◽  
Berenice P. Martel ◽  
Alma Chávez-Blanco ◽  
Alfonso Dueñas-González ◽  
...  
Keyword(s):  
Valproic Acid ◽  
Cell Lines ◽  
Water Solubility ◽  
Md Simulations ◽  
Pamam Dendrimer ◽  
Pamam Dendrimers ◽  
Force Microscopy ◽  
Micromolar Concentration ◽  
Atomic Force

Background: Our research group has developed some Valproic Acid (VPA) derivatives employed as anti-proliferative compounds targeting the HDAC8 enzyme. However, some of these compounds are poorly soluble in water. Objective: Employed the four generations of Polyamidoamine (G4 PAMAM) dendrimers as drug carriers of these compounds to increase their water solubility for further in vitro evaluation. Methods: VPA derivatives were subjected to Docking and Molecular Dynamics (MD) simulations to evaluate their affinity on G4 PAMAM. Then, HPLC-UV/VIS, 1H NMR, MALDI-TOF and atomic force microscopy were employed to establish the formation of the drug-G4 PAMAM complexes. Results: The docking results showed that the amide groups of VPA derivatives make polar interactions with G4 PAMAM, whereas MD simulations corroborated the stability of the complexes. HPLC UV/VIS experiments showed an increase in the drug water solubility which was found to be directly proportional to the amount of G4 PAMAM. 1H NMR showed a disappearance of the proton amine group signals, correlating with docking results. MALDI-TOF and atomic force microscopy suggested the drug-G4 PAMAM dendrimer complexes formation. Discussion: In vitro studies showed that G4 PAMAM has toxicity in the micromolar concentration in MDAMB- 231, MCF7, and 3T3-L1 cell lines. VPA CF-G4 PAMAM dendrimer complex showed anti-proliferative properties in the micromolar concentration in MCF-7 and 3T3-L1, and in the milimolar concentration in MDAMB- 231, whereas VPA MF-G4 PAMAM dendrimer complex didn’t show effects on the three cell lines employed. Conclusion: These results demonstrate that G4 PAMAM dendrimers are capableof transporting poorly watersoluble aryl-VPA derivate compounds to increase its cytotoxic activity against neoplastic cell lines.

scholarly journals Atomic Force Microscopy Investigation of the Interactions between the MCM Helicase and DNA

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 687
Author(s):  
Amna Abdalla Mohammed Khalid ◽  
Pietro Parisse ◽  
Barbara Medagli ◽  
Silvia Onesti ◽  
Loredana Casalis
Keyword(s):  
Atomic Force Microscopy ◽  
Nucleic Acid ◽  
Single Molecule ◽  
Protein Complex ◽  
The Other ◽  
Contour Length ◽  
Force Microscopy ◽  
Atomic Force ◽  
Mcm Complex ◽  
Dna Double Helix

The MCM (minichromosome maintenance) protein complex forms an hexameric ring and has a key role in the replication machinery of Eukaryotes and Archaea, where it functions as the replicative helicase opening up the DNA double helix ahead of the polymerases. Here, we present a study of the interaction between DNA and the archaeal MCM complex from Methanothermobacter thermautotrophicus by means of atomic force microscopy (AFM) single molecule imaging. We first optimized the protocol (surface treatment and buffer conditions) to obtain AFM images of surface-equilibrated DNA molecules before and after the interaction with the protein complex. We discriminated between two modes of interaction, one in which the protein induces a sharp bend in the DNA, and one where there is no bending. We found that the presence of the MCM complex also affects the DNA contour length. A possible interpretation of the observed behavior is that in one case the hexameric ring encircles the dsDNA, while in the other the nucleic acid wraps on the outside of the ring, undergoing a change of direction. We confirmed this topographical assignment by testing two mutants, one affecting the N-terminal β-hairpins projecting towards the central channel, and thus preventing DNA loading, the other lacking an external subdomain and thus preventing wrapping. The statistical analysis of the distribution of the protein complexes between the two modes, together with the dissection of the changes of DNA contour length and binding angle upon interaction, for the wild type and the two mutants, is consistent with the hypothesis. We discuss the results in view of the various modes of nucleic acid interactions that have been proposed for both archaeal and eukaryotic MCM complexes.

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