1,720,985 research outputs found
Virtual screening, structure based pharmacophore mapping, and molecular simulation studies of pyrido[2,3-d]pyrimidines as selective thymidylate synthase inhibitors
No full textHuman thymidylate synthase is the rate-limiting enzyme in the de novo synthesis of 2'-deoxythymidine-5'-monophosphate. dUMP (pyrimidine) and folate binding site hTS inhibitors showed resistance in colorectal cancer (CRC). In the present study, we have performed virtual screening of the pyrido[2,3-d]pyrimidine database, followed by binding free energy calculations, and pharmacophore mapping to design novel pyrido[2,3-d]pyrimidine derivatives to stabilize inactive confirmation of hTS. A library of 42 molecules was designed. Based on the molecular docking studies, four ligands (T36, T39, T40, and T13) were identified to have better interactions and docking scores with the catalytic sites [dUMP (pyrimidine) and folate binding sites] of hTS protein than standard drug, raltitrexed. To validate efficacy of the designed molecules, we performed molecular dynamics simulation studies at 1000 ns with principal component analysis and binding free energy calculations on the hTS protein, also drug likeness properties of all hits were in acceptable range. Compounds T36, T39, T40, and T13 interacted with the catalytic amino acid (Cys195), an essential amino acid for anticancer activity. The designed molecules stabilized the inactive conformation of hTS, resulting in the inhibition of hTS. The designed compounds will undergo synthesis and biological evaluation, which may yield selective, less toxic, and highly potent hTS inhibitors.Rezultati su dobiveni pomoću paketa za molekulsku dinamiku Amber 20
Computational and experimental therapeutic efficacy analysis of andrographolide phospholipid complex self-assembled nanoparticles against Neuro2a cells
No full textBackground: Neuroblastoma is one of the most common malignancies in childhood, accounts for approximately 7% of all malignancies. Andrographolide (AN) inhibits cancer cells progression via multiple pathways like cell cycle arrest, mitochondrial apoptosis, NF-κβ inhibition, and antiangiogenesis mechanism. Despite multiple ad vantages, application of AN is very limited due to its low aqueous solubility (6.39 ± 0.47 μg/mL), high lip ophilicity (log P ~ 2.632 ± 0.135), and reduced stability owing to pH sensitive lactone ring. Objectives and results: In present investigation, a molecular complex of AN with soya-L-α-phosphatidyl choline (SPC) was synthesized as ANSPC and characterized by FT-IR and1H NMR spectroscopy. Spectral and molecular simulation techniques confirmed the intermolecular interactions between the 14-OH group of AN and the N+(CH3)3part of SPC. In addition, molecular dynamics (MD) simulation was used to determine the degree of interaction between various proteins such as TNF-α, caspase-3, and Bcl-2. Later, ANSPC complex was trans formed in to self-assembled soft nanoparticles of size 201.8 ± 1.48 nm with PDI of 0.092 ± 0.004 and zeta potential of −21.7 ± 0.85 mV. The IC50 offree AN (8.319 μg/mL) and the self-assembled soft ANSPC nano particles (3.406 μg/mL ~ 1.2 μg of AN) against Neuro2a cells was estimated with significant (P < 0.05) dif ference. Interestingly, the self-assembled soft ANSPC nanoparticles showed better endocytosis compared to free AN in Neuro2a cells. In-vitrobiological assays confirmed that self-assembled soft ANSPC nanoparticles induces apoptosis in Neuro2a cells by declining the MMP (Δψm) and increasing the ROS generation. Conclusion: Self-assembled soft ANSPC nanoparticles warrant further in-depth antitumor study in xenograft model of neuroblastoma to establish the anticancer potential.Trajektroije su dobivene pomoću paketa za molekulsku dinamiku Amber 1
Computational and experimental therapeutic efficacy analysis of andrographolide phospholipid complex self-assembled nanoparticles against Neuro2a cells
No full textBackground: Neuroblastoma is one of the most common malignancies in childhood, accounts for approximately 7% of all malignancies. Andrographolide (AN) inhibits cancer cells progression via multiple pathways like cell cycle arrest, mitochondrial apoptosis, NF-κβ inhibition, and antiangiogenesis mechanism. Despite multiple ad vantages, application of AN is very limited due to its low aqueous solubility (6.39 ± 0.47 μg/mL), high lip ophilicity (log P ~ 2.632 ± 0.135), and reduced stability owing to pH sensitive lactone ring. Objectives and results: In present investigation, a molecular complex of AN with soya-L-α-phosphatidyl choline (SPC) was synthesized as ANSPC and characterized by FT-IR and1H NMR spectroscopy. Spectral and molecular simulation techniques confirmed the intermolecular interactions between the 14-OH group of AN and the N+(CH3)3part of SPC. In addition, molecular dynamics (MD) simulation was used to determine the degree of interaction between various proteins such as TNF-α, caspase-3, and Bcl-2. Later, ANSPC complex was trans formed in to self-assembled soft nanoparticles of size 201.8 ± 1.48 nm with PDI of 0.092 ± 0.004 and zeta potential of −21.7 ± 0.85 mV. The IC50 offree AN (8.319 μg/mL) and the self-assembled soft ANSPC nano particles (3.406 μg/mL ~ 1.2 μg of AN) against Neuro2a cells was estimated with significant (P < 0.05) dif ference. Interestingly, the self-assembled soft ANSPC nanoparticles showed better endocytosis compared to free AN in Neuro2a cells. In-vitrobiological assays confirmed that self-assembled soft ANSPC nanoparticles induces apoptosis in Neuro2a cells by declining the MMP (Δψm) and increasing the ROS generation. Conclusion: Self-assembled soft ANSPC nanoparticles warrant further in-depth antitumor study in xenograft model of neuroblastoma to establish the anticancer potential.Trajektroije su dobivene pomoću paketa za molekulsku dinamiku Amber 1
Gaussian field-based 3D-QSAR and molecular simulation studies to design potent pyrimidine–sulfonamide hybrids as selective BRAFV600E inhibitors
No full textThe “RAS-RAF-MEK-ERK” pathway is an important signaling pathway in melanoma. BRAFV600E (70–90%) is the most common mutation in this pathway. BRAF inhibitors have four types of conformers: type I (αC-IN/DFG-IN), type II (αC-IN/DFG-OUT), type I1/2 (αC-OUT/DFG-IN), and type I/II (αC-OUT/DFG-OUT). First- and second-generation BRAF inhibitors show resistance to BRAFV600E and are ineffective against malignancies induced by dimer BRAF mutants causing ‘paradoxical’ activation. In the present study, we performed molecular modeling of pyrimidine–sulfonamide hybrids inhibitors using 3D-QSAR, molecular docking, and molecular dynamics simulations. Previous reports reveal the importance of pyrimidine and sulfonamide moieties in the development of BRAFV600E inhibitors. Analysis of 3D-QSAR models provided novel pyrimidine sulfonamide hybrid BRAFV600E inhibitors. The designed compounds share similarities with several structural moieties present in first- and second-generation BRAF inhibitors. A total library of 88 designed compounds was generated and molecular docking studies were performed with them. Four molecules (T109, T183, T160, and T126) were identified as hits and selected for detailed studies. Molecular dynamics simulations were performed at 900 ns and binding was calculated. Based on molecular docking and simulation studies, it was found that the designed compounds have better interactions with the core active site [the nucleotide (ADP or ATP) binding site, DFG motif, and the phospho-acceptor site (activation segment) of BRAFV600E protein than previous inhibitors. Similar to the FDA-approved BRAFV600E inhibitors the developed compounds have [αC-OUT/DFG-IN] conformation. Compounds T126, T160 and T183 interacted with DIF (Leu505), making them potentially useful against BRAFV600E resistance and malignancies induced by dimer BRAF mutants. The synthesis and biological evaluation of the designed molecules is in progress, which may lead to some potent BRAFV600E selective inhibitors.Rezultati su dobiveni pomoću paketa za molekulsku dinamiku Amber 20
MD simulacije novosintetiziranih inhibitora u aktivnom mjestu BRAF proteina
No full textRezultati su dobiveni pomoću paketa za molekulsku dinamiku Amber 20
MD simulacije novosintetiziranih inhibitora u aktivnom mjestu BRAF proteina
No full textRezultati su dobiveni pomoću paketa za molekulsku dinamiku Amber 20
Gaussian field-based 3D-QSAR and molecular simulation studies to design potent pyrimidine–sulfonamide hybrids as selective BRAFV600E inhibitors
No full textThe “RAS-RAF-MEK-ERK” pathway is an important signaling pathway in melanoma. BRAFV600E (70–90%) is the most common mutation in this pathway. BRAF inhibitors have four types of conformers: type I (αC-IN/DFG-IN), type II (αC-IN/DFG-OUT), type I1/2 (αC-OUT/DFG-IN), and type I/II (αC-OUT/DFG-OUT). First- and second-generation BRAF inhibitors show resistance to BRAFV600E and are ineffective against malignancies induced by dimer BRAF mutants causing ‘paradoxical’ activation. In the present study, we performed molecular modeling of pyrimidine–sulfonamide hybrids inhibitors using 3D-QSAR, molecular docking, and molecular dynamics simulations. Previous reports reveal the importance of pyrimidine and sulfonamide moieties in the development of BRAFV600E inhibitors. Analysis of 3D-QSAR models provided novel pyrimidine sulfonamide hybrid BRAFV600E inhibitors. The designed compounds share similarities with several structural moieties present in first- and second-generation BRAF inhibitors. A total library of 88 designed compounds was generated and molecular docking studies were performed with them. Four molecules (T109, T183, T160, and T126) were identified as hits and selected for detailed studies. Molecular dynamics simulations were performed at 900 ns and binding was calculated. Based on molecular docking and simulation studies, it was found that the designed compounds have better interactions with the core active site [the nucleotide (ADP or ATP) binding site, DFG motif, and the phospho-acceptor site (activation segment) of BRAFV600E protein than previous inhibitors. Similar to the FDA-approved BRAFV600E inhibitors the developed compounds have [αC-OUT/DFG-IN] conformation. Compounds T126, T160 and T183 interacted with DIF (Leu505), making them potentially useful against BRAFV600E resistance and malignancies induced by dimer BRAF mutants. The synthesis and biological evaluation of the designed molecules is in progress, which may lead to some potent BRAFV600E selective inhibitors.Rezultati su dobiveni pomoću paketa za molekulsku dinamiku Amber 20
Virtual screening, structure based pharmacophore mapping, and molecular simulation studies of pyrido[2,3-d]pyrimidines as selective thymidylate synthase inhibitors
No full textHuman thymidylate synthase is the rate-limiting enzyme in the de novo synthesis of 2'-deoxythymidine-5'-monophosphate. dUMP (pyrimidine) and folate binding site hTS inhibitors showed resistance in colorectal cancer (CRC). In the present study, we have performed virtual screening of the pyrido[2,3-d]pyrimidine database, followed by binding free energy calculations, and pharmacophore mapping to design novel pyrido[2,3-d]pyrimidine derivatives to stabilize inactive confirmation of hTS. A library of 42 molecules was designed. Based on the molecular docking studies, four ligands (T36, T39, T40, and T13) were identified to have better interactions and docking scores with the catalytic sites [dUMP (pyrimidine) and folate binding sites] of hTS protein than standard drug, raltitrexed. To validate efficacy of the designed molecules, we performed molecular dynamics simulation studies at 1000 ns with principal component analysis and binding free energy calculations on the hTS protein, also drug likeness properties of all hits were in acceptable range. Compounds T36, T39, T40, and T13 interacted with the catalytic amino acid (Cys195), an essential amino acid for anticancer activity. The designed molecules stabilized the inactive conformation of hTS, resulting in the inhibition of hTS. The designed compounds will undergo synthesis and biological evaluation, which may yield selective, less toxic, and highly potent hTS inhibitors.Rezultati su dobiveni pomoću paketa za molekulsku dinamiku Amber 20
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
