Synthesis, biological evaluation and molecular docking studies of new amides of 4-bromothiocolchicine as anticancer agents.

7 months 1 week ago
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Synthesis, biological evaluation and molecular docking studies of new amides of 4-bromothiocolchicine as anticancer agents.

Bioorg Med Chem. 2019 Oct 08;:115144

Authors: Klejborowska G, Urbaniak A, Preto J, Maj E, Moshari M, Wietrzyk J, Tuszynski JA, Chambers TC, Huczyński A

Abstract
Colchicine is the major alkaloid isolated from the plant Colchicum autumnale, which shows strong therapeutic effects towards different types of cancer. However, due to the toxicity of colchicine towards normal cells its application is limited. To address this issue we synthesized a series of seven triple-modified 4-bromothiocolchicine analogues with amide moieties. These novel derivatives were active in the nanomolar range against several different cancer cell lines and primary acute lymphoblastic leukemia cells, specifically compounds: 5-9 against primary ALL-5 (IC50 = 5.3-14 nM), 5, 7-9 against A549 (IC50 = 10 nM), 5, 7-9 against MCF-7 (IC50 = 11 nM), 5-9 against LoVo (IC50 = 7-12 nM), and 5, 7-9 against LoVo/DX (IC50 = 48-87 nM). These IC50 values were lower than those obtained for unmodified colchicine and common anticancer drugs such as doxorubicin and cisplatin. Further studies revealed that colchicine and selected analogues induced characteristics of apoptotic cell death but manifested their effects in different phases of the cell cycle in MCF-7 versus ALL-5 cells. Specifically, while colchicine and the studied derivatives arrested MCF-7 cells in mitosis, very little mitotically arrested ALL-5 cells were observed, suggesting effects were manifest instead in interphase. We also developed an in silico model of the mode of binding of these compounds to their primary target, β-tubulin. We conducted a correlation analysis (linear regression) between the calculated binding energies of colchicine derivatives and their anti-proliferative activity, and determined that the obtained correlation coefficients strongly depend on the type of cells used.

PMID: 31653441 [PubMed - as supplied by publisher]

GLUT1 and TUBB4 in Glioblastoma Could be Efficacious Targets.

8 months 3 weeks ago
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GLUT1 and TUBB4 in Glioblastoma Could be Efficacious Targets.

Cancers (Basel). 2019 Sep 05;11(9):

Authors: Guda MR, Labak CM, Omar SI, Asuthkar S, Airala S, Tuszynski J, Tsung AJ, Velpula KK

Abstract
Glioblastoma multiforme (GBM) is the most aggressive and deadly brain tumor, portending a median 13-month survival even following gross total resection with adjuvant chemotherapy and radiotherapy. This prognosis necessitates improved therapies for the disease. A target of interest for novel chemotherapies is the Warburg Effect, which describes the tumor's shift away from oxidative phosphorylation towards glycolysis. Here, we elucidate GLUT1 (Glucose transporter 1) and one of its associated binding partners, TUBB4 (Tubulin 4), as potentially druggable targets in GBM. Using data mining approach, we demonstrate that GLUT1 is overexpressed as a function of tumor grade in astrocytoma's and that its overexpression is associated with poorer prognosis. Using both mass spectrometry performed on hGBM (human glioblastoma patient specimen) and in silico modeling, we show that GLUT1 interacts with TUBB4, and more accurately demonstrates GLUT1's binding with fasentin. Proximity ligation assay (PLA) and immunoprecipitation studies confirm GLUT1 interaction with TUBB4. Treatment of GSC33 and GSC28 cells with TUBB4 inhibitor, CR-42-24, reduces the expression of GLUT1 however, TUBB4 expression is unaltered upon fasentin treatment. Using human pluripotent stem cell antibody array, we demonstrate reduced levels of Oct3/4, Nanog, Sox2, Sox17, Snail and VEGFR2 (Vascular endothelial growth factor receptor 2) upon CR-42-24 treatment. Overall, our data confirm that silencing TUBB4 or GLUT1 reduce GSC tumorsphere formation, self-renewal and proliferation in vitro. These findings suggest GLUT1 and its binding partner TUBB4 as druggable targets that warrant further investigation in GBM.

PMID: 31491891 [PubMed]

Synthesis, antiproliferative activity and molecular docking studies of 4-chlorothiocolchicine analogues.

9 months ago
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Synthesis, antiproliferative activity and molecular docking studies of 4-chlorothiocolchicine analogues.

Chem Biol Drug Des. 2019 Sep 04;:

Authors: Klejborowska G, Moshari M, Maj E, Majcher U, Preto J, Wietrzyk J, Tuszynski JA, Huczyński A

Abstract
Colchicine is a therapeutic agent currently used in therapies of many diseases. It also shows antimitotic effects and its high cytotoxic activity against different cancer cell lines has been demonstrated many times. To overcome the limitations of colchicine use in anticancer therapy, we synthesized a series of novel triple-modified 4-chloro-7-carbamatethiocolchicines. All the synthesized compounds have been tested in vitro to evaluate their cytotoxicity towards A549, MCF-7, LoVo, LoVo/DX and BALB/3T3 cell lines. Additionally, their mode of binding to ß-tubulin was evaluated in silico. The majority of triple-modified colchicine derivatives exhibited significantly higher cytotoxicity than colchicine, doxorubicin and cisplatin against tested cancerous cell lines with much higher selectivity index values for four of them. This article is protected by copyright. All rights reserved.

PMID: 31483093 [PubMed - as supplied by publisher]

Probing the Basis of α-Synuclein Aggregation by Comparing Simulations to Single-Molecule Experiments.

9 months ago
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Probing the Basis of α-Synuclein Aggregation by Comparing Simulations to Single-Molecule Experiments.

Biophys J. 2019 Aug 16;:

Authors: Churchill CDM, Healey MA, Preto J, Tuszynski JA, Woodside MT

Abstract
Intrinsically disordered proteins often play an important role in protein aggregation. However, it is challenging to determine the structures and interactions that drive the early stages of aggregation because they are transient and obscured in a heterogeneous mixture of disordered states. Even computational methods are limited because the lack of ordered structure makes it difficult to ensure that the relevant conformations are sampled. We address these challenges by integrating atomistic simulations with high-resolution single-molecule measurements reported previously, using the measurements to help discern which parts of the disordered ensemble of structures in the simulations are most probable while using the simulations to identify residues and interactions that are important for oligomer stability. This approach was applied to α-synuclein, an intrinsically disordered protein that aggregates in the context of Parkinson's disease. We simulated single-molecule pulling experiments on dimers, the minimal oligomer, and compared them to force spectroscopy measurements. Force-extension curves were simulated starting from a set of 66 structures with substantial structured content selected from the ensemble of dimer structures generated at zero force via Monte Carlo simulations. The pattern of contour length changes as the structures unfolded through intermediate states was compared to the results from optical trapping measurements on the same dimer to discern likely structures occurring in the measurements. Simulated pulling curves were generally consistent with experimental data but with a larger number of transient intermediates. We identified an ensemble of β-rich dimer structures consistent with the experimental data from which dimer interfaces could be deduced. These results suggest specific druggable targets in the structural motifs of α-synuclein that may help prevent the earliest steps of oligomerization.

PMID: 31477241 [PubMed - as supplied by publisher]

Tubulin Polarizability in Aqueous Suspensions.

9 months ago
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Tubulin Polarizability in Aqueous Suspensions.

ACS Omega. 2019 May 31;4(5):9144-9149

Authors: Guzman-Sepulveda JR, Wu R, Kalra AP, Aminpour M, Tuszynski JA, Dogariu A

Abstract
We report accurate optical measurements of tubulin polarizability in aqueous suspensions. We determined the dependence of polarizability on tubulin concentration and on the suspension's pH, providing benchmark numbers for quantifying the optical response of this protein in various artificial and cellular environments. We compare our measurement data with a few estimates found in the previous literature and also with our simplified model estimations.

PMID: 31460002 [PubMed]

Magnetic Monopole Search with the Full MoEDAL Trapping Detector in 13 TeV pp Collisions Interpreted in Photon-Fusion and Drell-Yan Production.

9 months 4 weeks ago
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Magnetic Monopole Search with the Full MoEDAL Trapping Detector in 13 TeV pp Collisions Interpreted in Photon-Fusion and Drell-Yan Production.

Phys Rev Lett. 2019 Jul 12;123(2):021802

Authors: Acharya B, Alexandre J, Baines S, Benes P, Bergmann B, Bernabéu J, Bevan A, Branzas H, Campbell M, Cecchini S, Cho YM, de Montigny M, De Roeck A, Ellis JR, El Sawy M, Fairbairn M, Felea D, Frank M, Hays J, Hirt AM, Janecek J, Kim DW, Korzenev A, Lacarrère DH, Lee SC, Leroy C, Levi G, Lionti A, Mamuzic J, Margiotta A, Mauri N, Mavromatos NE, Mermod P, Mieskolainen M, Millward L, Mitsou VA, Orava R, Ostrovskiy I, Papavassiliou J, Parker B, Patrizii L, Păvălaş GE, Pinfold JL, Popa V, Pozzato M, Pospisil S, Rajantie A, Ruiz de Austri R, Sahnoun Z, Sakellariadou M, Santra A, Sarkar S, Semenoff G, Shaa A, Sirri G, Sliwa K, Soluk R, Spurio M, Staelens M, Suk M, Tenti M, Togo V, Tuszyński JA, Vento V, Vives O, Vykydal Z, Wall A, Zgura IS, MoEDAL Collaboration

Abstract
MoEDAL is designed to identify new physics in the form of stable or pseudostable highly ionizing particles produced in high-energy Large Hadron Collider (LHC) collisions. Here we update our previous search for magnetic monopoles in Run 2 using the full trapping detector with almost four times more material and almost twice more integrated luminosity. For the first time at the LHC, the data were interpreted in terms of photon-fusion monopole direct production in addition to the Drell-Yan-like mechanism. The MoEDAL trapping detector, consisting of 794 kg of aluminum samples installed in the forward and lateral regions, was exposed to 4.0  fb^{-1} of 13 TeV proton-proton collisions at the LHCb interaction point and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges equal to or above the Dirac charge are excluded in all samples. Monopole spins 0, ½, and 1 are considered and both velocity-independent and-dependent couplings are assumed. This search provides the best current laboratory constraints for monopoles with magnetic charges ranging from two to five times the Dirac charge.

PMID: 31386510 [PubMed - in process]

Targeting DNA Repair in Tumor Cells via Inhibition of ERCC1-XPF.

10 months ago
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Targeting DNA Repair in Tumor Cells via Inhibition of ERCC1-XPF.

J Med Chem. 2019 Aug 01;:

Authors: Elmenoufy A, Gentile F, Jay D, Karimi-Busheri F, Yang X, Soueidan OM, Weilbeer C, Mani RS, Barakat KH, Tuszynski J, Weinfeld M, West FG

Abstract
The ERCC1-XPF heterodimer is a 5´-3´ structure-specific endonuclease, which plays an essential role in several DNA repair pathways in mammalian cells. ERCC1-XPF is primarily involved in the repair of chemically-induced helix-distorting and bulky DNA lesions, such as cyclobutane pyrimidine dimers (CPDs), and DNA interstrand crosslinks. Inhibition of ERCC1-XPF has been shown to potentiate cytotoxicity of platinum-based drugs and cyclophosphamide in cancer cells. In this study, the previously described ERCC1-XPF inhibitor 4-((6-chloro-2-methoxyacridin-9-yl)amino)-2-((4-methylpiperazin-1-yl)methyl)phenol (F06) was used as a reference compound. Following the outcome of docking-based virtual screening (VS), we synthesized seven novel derivatives of F06 that were identified in silico as being likely to have high binding affinity for the ERCC1-XPF heterodimerization interface by interacting with the XPF double helix-hairpin-helix (HhH2) domain. Two of the new compounds, 4-((6-chloro-2-methoxyacridin-9-yl)amino)-2-((4-cyclohexylpiperazin-1-yl)methyl)phenol (compound 3) and 4-((6-chloro-2-methoxyacridin-9-yl)amino)-2-((4-(2-(dimethylamino)ethyl) piperazin-1-yl) methyl) phenol (compound 4), were shown to be potent inhibitors of ERCC1-XPF activity in vitro. Compound 4 showed a significant inhibition of the removal of CPDs in UV-irradiated cells and the capacity to sensitize colorectal cancer cells to UV radiation and cyclophosphamide.

PMID: 31369707 [PubMed - as supplied by publisher]

Tubulin response to intense nanosecond-scale electric field in molecular dynamics simulation.

10 months 2 weeks ago
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Tubulin response to intense nanosecond-scale electric field in molecular dynamics simulation.

Sci Rep. 2019 Jul 19;9(1):10477

Authors: Marracino P, Havelka D, Průša J, Liberti M, Tuszynski J, Ayoub AT, Apollonio F, Cifra M

Abstract
Intense pulsed electric fields are known to act at the cell membrane level and are already being exploited in biomedical and biotechnological applications. However, it is not clear if electric pulses within biomedically-attainable parameters could directly influence intra-cellular components such as cytoskeletal proteins. If so, a molecular mechanism of action could be uncovered for therapeutic applications of such electric fields. To help clarify this question, we first identified that a tubulin heterodimer is a natural biological target for intense electric fields due to its exceptional electric properties and crucial roles played in cell division. Using molecular dynamics simulations, we then demonstrated that an intense - yet experimentally attainable - electric field of nanosecond duration can affect the bβ-tubulin's C-terminus conformations and also influence local electrostatic properties at the GTPase as well as the binding sites of major tubulin drugs site. Our results suggest that intense nanosecond electric pulses could be used for physical modulation of microtubule dynamics. Since a nanosecond pulsed electric field can penetrate the tissues and cellular membranes due to its broadband spectrum, our results are also potentially significant for the development of new therapeutic protocols.

PMID: 31324834 [PubMed - in process]

How signals of calcium ions initiate the beats of cilia and flagella.

11 months 2 weeks ago
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How signals of calcium ions initiate the beats of cilia and flagella.

Biosystems. 2019 Aug;182:42-51

Authors: Satarić MV, Nemeš T, Sekulić D, Tuszynski JA

Abstract
Cilia and flagella are cell organelles serving basic roles in cellular motility. Ciliary movement is performed by a sweeping-like repeated bending motion, which gives rise to a self-propagating "ciliary beat". The hallmark structure in cilia is the axoneme, a stable architecture of microtubule doublets. The motion of axoneme is powered by the axonemal dynein motor family powered by ATP hydrolysis. It is still unclear how the organized beat of cilium and flagella emerges from the combined action of hundreds of dynein molecules. It has been hypothesized that such coordination is mediated by mechanical stress due to transverse, radial or sliding deformations. The beating asymmetry is crucial for airway ciliary function and it requires tubulin glutamination a unique posttranslational modification of C-termini of constituent microtubules that is highly abundant in cilia and flagella. The exact role of tubulin glutamination in ciliary or flagellar function is still unclear. In this paper we analyze the role of calcium (Ca2+) ions based on the experimental evidence that the flagellar asymmetry can be increased due to the entry of extracellular Ca2+ through, for example, the nimodipine-sensitive pathway located in the flagella. We propose a new scenario based on the polyelectrolyte properties of cellular microtubules (MTs) such that dynamic influx of Ca2+ ions provides the initiation and synchronization of dynein sliding along microtubules. We also point out the possible interplay between tubulin polyglutaminated C-termini and localized pulses of Ca2+ ions along microtubules.

PMID: 31202860 [PubMed - indexed for MEDLINE]

Molecular orbitals of delocalized electron clouds in neuronal domains.

11 months 2 weeks ago
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Molecular orbitals of delocalized electron clouds in neuronal domains.

Biosystems. 2019 Sep;183:103982

Authors: Poznanski RR, Cacha LA, Latif AZA, Salleh SH, Ali J, Yupapin P, Tuszynski JA, Ariff TM

Abstract
We have further developed the two-brains hypothesis as a form of complementarity (or complementary relationship) of endogenously induced weak magnetic fields in the electromagnetic brain. The locally induced magnetic field between electron magnetic dipole moments of delocalized electron clouds in neuronal domains is complementary to the exogenous electromagnetic waves created by the oscillating molecular dipoles in the electro-ionic brain. In this paper, we mathematically model the operation of the electromagnetic grid, especially in regard to the functional role of atomic orbitals of dipole-bound delocalized electrons. A quantum molecular dynamic approach under quantum equilibrium conditions is taken to illustrate phase differences between quasi-free electrons tethered to an oscillating molecular core. We use a simplified version of the many-body problem to analytically solve the macro-quantum wave equation (equivalent to the Kohn-Sham equation). The resultant solution for the mechanical angular momentum can be used to approximate the molecular orbital of the dipole-bound delocalized electrons. In addition to non-adiabatic motion of the molecular core, 'guidance waves' may contribute to the delocalized macro-quantum wave functions in generating nonlocal phase correlations. The intrinsic magnetic properties of the origins of the endogenous electromagnetic field are considered to be a nested hierarchy of electromagnetic fields that may also include electromagnetic patterns in three-dimensional space. The coupling between the two-brains may involve an 'anticipatory affect' based on the conceptualization of anticipation as potentiality, arising either from the macro-quantum potential energy or from the electrostatic effects of residual charges in the quantum and classical subsystems of the two-brains that occurs through partitioning of the potential energy of the combined quantum molecular dynamic system.

PMID: 31195028 [PubMed - indexed for MEDLINE]

The Role of Structural Polymorphism in Driving the Mechanical Performance of the Alzheimer's Beta Amyloid Fibrils.

1 year ago
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The Role of Structural Polymorphism in Driving the Mechanical Performance of the Alzheimer's Beta Amyloid Fibrils.

Front Bioeng Biotechnol. 2019;7:83

Authors: Grasso G, Rebella M, Morbiducci U, Tuszynski JA, Danani A, Deriu MA

Abstract
Alzheimer's Disease (AD) is related with the abnormal aggregation of amyloid β-peptides Aβ1-40 and Aβ1-42, the latter having a polymorphic character which gives rise to U- or S-shaped fibrils. Elucidating the role played by the nanoscale-material architecture on the amyloid fibril stability is a crucial breakthrough to better understand the pathological nature of amyloid structures and to support the rational design of bio-inspired materials. The computational study here presented highlights the superior mechanical behavior of the S-architecture, characterized by a Young's modulus markedly higher than the U-shaped architecture. The S-architecture showed a higher mechanical resistance to the enforced deformation along the fibril axis, consequence of a better interchain hydrogen bonds' distribution. In conclusion, this study, focusing the attention on the pivotal multiscale relationship between molecular phenomena and material properties, suggests the S-shaped Aβ1-42 species as a target of election in computational screen/design/optimization of effective aggregation modulators.

PMID: 31106199 [PubMed]

Theorizing how the brain encodes consciousness based on negentropic entanglement.

1 year ago
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Theorizing how the brain encodes consciousness based on negentropic entanglement.

J Integr Neurosci. 2019 03 30;18(1):1-10

Authors: Poznanski RR, Cacha LA, Latif AZA, Salleh SH, Ali J, Yupapin P, Tuszynski JA, Tengku MA

Abstract
The physicality of subjectivity is explained through a theoretical conceptualization of guidance waves informing meaning in negentropically entangled non-electrolytic brain regions. Subjectivity manifests its influence at the microscopic scale of matter originating from de Broglie 'hidden' thermodynamics as action of guidance waves. The preconscious experienceability of subjectivity is associated with a nested hierarchy of microprocesses, which are actualized as a continuum of patterns of discrete atomic microfeels (or "qualia"). The mechanism is suggested to be through negentropic entanglement of hierarchical thermodynamic transfer of information as thermo-qubits originating from nonpolarized regions of actin-binding proteinaceous structures of nonsynaptic spines. The resultant continuous stream of intrinsic information entails a negentropic action (or experiential flow of thermo-quantum internal energy that results in a negentropic force) which is encoded through the non-zero real component of the mean approximation of the negentropic force as a 'consciousness code'. Consciousness consisting of two major subprocesses: (1) preconscious experienceability and (2) conscious experience. Both are encapsulated by nonreductive physicalism and panexperiential materialism. The subprocess (1) governing "subjectivity" carries many microprocesses leading to the actualization of discrete atomic microfeels by the 'consciousness code'. These atomic microfeels constitute internal energy that results in the transfer intrinsic information in terms of thermo-qubits. These thermo-qubits are realized as thermal entropy and sensed by subprocess (2) governing "self-awareness" in conscious experience.

PMID: 31091842 [PubMed - indexed for MEDLINE]

An Overview of Molecular Modeling for Drug Discovery with Specific Illustrative Examples of Applications.

1 year ago
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An Overview of Molecular Modeling for Drug Discovery with Specific Illustrative Examples of Applications.

Molecules. 2019 Apr 30;24(9):

Authors: Aminpour M, Montemagno C, Tuszynski JA

Abstract
In this paper we review the current status of high-performance computing applications in the general area of drug discovery. We provide an introduction to the methodologies applied at atomic and molecular scales, followed by three specific examples of implementation of these tools. The first example describes in silico modeling of the adsorption of small molecules to organic and inorganic surfaces, which may be applied to drug delivery issues. The second example involves DNA translocation through nanopores with major significance to DNA sequencing efforts. The final example offers an overview of computer-aided drug design, with some illustrative examples of its usefulness.

PMID: 31052253 [PubMed - indexed for MEDLINE]

The molecular mechanism of action of methylene quinuclidinone and its effects on the structure of p53 mutants.

1 year 4 months ago
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The molecular mechanism of action of methylene quinuclidinone and its effects on the structure of p53 mutants.

Oncotarget. 2018 Dec 14;9(98):37137-37156

Authors: Omar SI, Tuszynski J

Abstract
One of the most important tumor suppressor proteins in eukaryotic cells is the transcription factor called p53. The importance of this protein in cells comes from the fact that it regulates a wide variety of cellular processes including the cell cycle, metabolism, DNA repair, senescence and apoptosis. In cancer cells, p53 is a major target as the most mutated protein, which has led to the search for potential activators of the mutant protein. Currently, the only mutated-p53 activator in clinical trials is a small molecule called APR-246. There is evidence that the active metabolite of APR-246 binds covalently to mutant p53 and restores its wild-type (wt) activity. In this work, we created atomistic in silico models of the wt, mutant and drugged mutant p53 proteins each in complex with DNA. Using molecular dynamics simulations we generated equilibrated models of the complexes. Detailed analysis revealed that the binding of the APR-246 active metabolite to the mutant proteins alters their interaction with DNA. In particular, the binding of the molecule at loop L1 of the protein allows the loop to anchor the protein to DNA similarly to wt p53. Several important p53-DNA interactions lost due to mutation were also restored in the drugged mutants. These findings, not only provide a possible mechanism of action of this drug, but also criteria to use in virtual screening campaigns for other p53 activators.

PMID: 30647850 [PubMed]

EDEn-Electroceutical Design Environment: Ion Channel Tissue Expression Database with Small Molecule Modulators.

1 year 5 months ago
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EDEn-Electroceutical Design Environment: Ion Channel Tissue Expression Database with Small Molecule Modulators.

iScience. 2018 Dec 11;11:42-56

Authors: Churchill CDM, Winter P, Tuszynski JA, Levin M

Abstract
The emerging field of bioelectricity has revealed numerous new roles for ion channels beyond the nervous system, which can be exploited for applications in regenerative medicine. Developing such biomedical interventions for birth defects, cancer, traumatic injury, and bioengineering first requires knowledge of ion channel targets expressed in tissues of interest. This information can then be used to select combinations of small molecule inhibitors and/or activators that manipulate the bioelectric state. Here, we provide an overview of electroceutical design environment (EDEn), the first bioinformatic platform that facilitates the design of such therapeutic strategies. This database includes information on ion channels and ion pumps, linked to known chemical modulators and their properties. The database also provides information about the expression levels of the ion channels in over 100 tissue types. The graphical interface allows the user to readily identify chemical entities that can alter the electrical properties of target cells and tissues.

PMID: 30590250 [PubMed - as supplied by publisher]

Synthesis of small peptide compounds, molecular docking, and inhibitory activity evaluation against phosphatases PTP1B and SHP2.

1 year 5 months ago
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Synthesis of small peptide compounds, molecular docking, and inhibitory activity evaluation against phosphatases PTP1B and SHP2.

Drug Des Devel Ther. 2018;12:4139-4147

Authors: Kostrzewa T, Sahu KK, Gorska-Ponikowska M, Tuszynski JA, Kuban-Jankowska A

Abstract
Background: The protein tyrosine phosphatases PTP1B and SHP2 are promising drug targets in treatment design for breast cancer. Searching for specific inhibitors of their activity has recently become the challenge of many studies. Previous work has indicated that the promising PTP inhibitors may be small compounds that are able to bind and interact with amino residues from the binding site.
Purpose: The main goal of our study was to synthesize and analyze the effect of selected small peptide inhibitors on oncogenic PTP1B and SHP2 enzymatic activity and viability of MCF7 breast cancer cells. We also performed computational analysis of peptides binding with allosteric sites of PTP1B and SHP2 phosphatases.
Methods: We measured the inhibitory activity of compounds utilizing recombinant enzymes and MCF7 cell line. Computational analysis involved docking studies of binding conformation and interactions of inhibitors with allosteric sites of phosphatases.
Results: The results showed that the tested compounds decrease the enzymatic activity of phosphatases PTP1B and SHP2 with IC50 values in micromolar ranges. We observed higher inhibitory activity of dipeptides than tripeptides. Phe-Asp was the most effective against SHP2 enzymatic activity, with IC50=5.2±0.4 µM. Micromolar concentrations of tested dipeptides also decreased the viability of MCF7 breast cancer cells, with higher inhibitory activity observed for the Phe-Asp peptide. Moreover, the peptides tested were able to bind and interact with allosteric sites of PTP1B and SHP2 phosphatases.
Conclusion: Our research showed that small peptide compounds can be considered for the design of specific inhibitors of oncogenic protein tyrosine phosphatases.

PMID: 30584278 [PubMed - indexed for MEDLINE]

Synthesis and Biological Evaluation of Novel Triple-Modified Colchicine Derivatives as Potent Tubulin-Targeting Anticancer Agents.

1 year 6 months ago
Related Articles

Synthesis and Biological Evaluation of Novel Triple-Modified Colchicine Derivatives as Potent Tubulin-Targeting Anticancer Agents.

Cells. 2018 Nov 19;7(11):

Authors: Majcher U, Klejborowska G, Kaik M, Maj E, Wietrzyk J, Moshari M, Preto J, Tuszynski JA, Huczyński A

Abstract
Specific modifications of colchicine followed by synthesis of its analogues have been tested in vitro with the objective of lowering colchicine toxicity. Our previous studies have clearly shown the anticancer potential of double-modified colchicine derivatives in C-7 and C-10 positions. Here, a series of novel triple-modified colchicine derivatives is reported. They have been obtained following a four-step strategy. In vitro cytotoxicity of these compounds has been evaluated against four human tumor cell lines (A549, MCF-7, LoVo, and LoVo/DX). Additionally, the mode of binding of the synthesized compounds was evaluated in silico using molecular docking to a 3D structure of β-tubulin based on crystallographic data from the Protein Data Bank and homology methodology. Binding free energy estimates, binding poses, and MlogP values of the compounds were obtained. All triple-modified colchicine derivatives were shown to be active at nanomolar concentrations against three of the investigated cancer cell lines (A549, MCF-7, LoVo). Four of them also showed higher potency against tumor cells over normal cells as confirmed by their high selectivity index values. A vast majority of the synthesized derivatives exhibited several times higher cytotoxicity than colchicine, doxorubicin, and cisplatin.

PMID: 30463236 [PubMed]

Antiproliferative Activity and Molecular Docking of Novel Double-Modified Colchicine Derivatives.

1 year 6 months ago
Related Articles

Antiproliferative Activity and Molecular Docking of Novel Double-Modified Colchicine Derivatives.

Cells. 2018 Nov 01;7(11):

Authors: Majcher U, Klejborowska G, Moshari M, Maj E, Wietrzyk J, Bartl F, Tuszynski JA, Huczyński A

Abstract
Microtubules are tubulin polymer structures, which are indispensable for cell growth and division. Its constituent protein β-tubulin has been a common drug target for various diseases including cancer. Colchicine has been used to treat gout, but it has also been an investigational anticancer agent with a known antimitotic effect on cells. However, the use of colchicine as well as many of its derivatives in long-term treatment is hampered by their high toxicity. To create more potent anticancer agents, three novel double-modified colchicine derivatives have been obtained by structural modifications in C-4 and C-10 positions. The binding affinities of these derivatives of colchicine with respect to eight different isotypes of human β-tubulin have been calculated using docking methods. In vitro cytotoxicity has been evaluated against four human tumor cell lines (A549, MCF-7, LoVo and LoVo/DX). Computer simulations predicted the binding modes of these compounds and hence the key residues involved in the interactions between tubulin and the colchicine derivatives. Two of the obtained derivatives, 4-bromothiocolchicine and 4-iodothiocolchicine, were shown to be active against three of the investigated cancer cell lines (A549, MCF-7, LoVo) with potency at nanomolar concentrations and a higher relative affinity to tumor cells over normal cells.

PMID: 30388878 [PubMed]

Synthesis, antiproliferative activity and molecular docking of thiocolchicine urethanes.

1 year 8 months ago
Related Articles

Synthesis, antiproliferative activity and molecular docking of thiocolchicine urethanes.

Bioorg Chem. 2018 12;81:553-566

Authors: Majcher U, Urbaniak A, Maj E, Moshari M, Delgado M, Wietrzyk J, Bartl F, Chambers TC, Tuszynski JA, Huczyński A

Abstract
A number of naturally occurring compounds such as paclitaxel, vinblastine, combretastatin, and colchicine exert their therapeutic effect by changing the dynamics of tubulin and its polymer form, microtubules. The identification of tubulin as a potential target for anticancer drugs has led to extensive research followed by clinical development of numerous compounds from several families. In this paper we report on the design, synthesis and in vitro evaluation of a group of thiocolchicine derivatives, modified at ring-B, labelled here compounds 4-14. These compounds have been obtained in a simple reaction of 7-deacetyl-10-thiocolchicine 3 with eleven different alcohols in the presence of triphosgene. These novel agents have been checked for anti-proliferative activity against four human cancer cell lines and their mode of action has been confirmed as colchicine binding site inhibition (CBSI) using molecular docking. Molecular simulations provided rational tubulin binding models for the tested compounds. On the basis of in vitro tests, derivatives 4-8 and 14 demonstrated the highest potency against MCF-7, LoVo and A549 tumor cell lines (IC50 values = 0.009-0.014 μM). They were more potent and characterized by a higher selectivity index than several standard chemotherapeutics including cisplatin and doxorubicin as well as unmodified colchicine. Further, studies revealed that colchicine and its several derivatives arrested MCF-7 cells in mitosis, while its selected derivatives caused microtubule depolymerization.

PMID: 30248507 [PubMed - indexed for MEDLINE]

Tubulin's response to external electric fields by molecular dynamics simulations.

1 year 8 months ago
Related Articles

Tubulin's response to external electric fields by molecular dynamics simulations.

PLoS One. 2018;13(9):e0202141

Authors: Timmons JJ, Preto J, Tuszynski JA, Wong ET

Abstract
Tubulin heterodimers are the building blocks of microtubules and disruption of their dynamics is exploited in the treatment of cancer. Electric fields at certain frequencies and magnitudes are believed to do the same. Here, the tubulin dimer's response to external electric fields was determined by atomistic simulation. External fields from 50 to 750 kV/cm, applied for 10 ns, caused significant conformational rearrangements that were dependent upon the field's directionality. Charged and flexible regions, including the α:H1-B2 loop, β:M-loop, and C-termini, were susceptible. Closer inspection of the α:H1-B2 loop in lower strength fields revealed that these effects were consistent and proportional to field strength, and the findings indicate that external electric fields modulate the stability of microtubules through conformational changes to key loops involved in lateral contacts. We also find evidence that tubulin's curvature and elongation are affected, and external electric fields may bias tubulin towards depolymerization.

PMID: 30231050 [PubMed - indexed for MEDLINE]