RESUMO
A facile cost-effective green synthesis approach has been used to synthesize carbon-dot (CDs) from the Kernel part of theAzadirachta Indicaseeds and investigated their fluorescent and metal ions sensing capability and also used for the delivery of drugs. Metallic ions such as Ca2+, K+, Na+, Fe3+,and Zn2+which are biologically important for many reactions and are selectively detected through the novel CDs. The resultant dot size of CDs (â¼4 nm) is useful to eliminate the 'Achilles heel' problems, which is associated with the Zn2+in the body and its detection is a very challenging task. It is found that the sensitivity of CDs for the detection of Zn2+can be regulated by using different solvents. These CDs can also be used as a sensing probe for the selective detection of Fe3+at a very low concentration of solution (â¼5 µM). The synthesis method of CDs reported here is cost-effective, very fast and it is highly selective towards Fe3+and Zn2+. Due to the fast response capability of these CDs, logic gate operation is achieved and it provides a new understanding to construct potential next-generation molecular devices for the detection of different biomolecules with high selectivity. Additionally, these CDs are biocompatible against normal healthy cells, capable of loading small biomolecules and drugs due to their porous nature, and exhibited potential impact for breast cancer therapy. It is observed that a significant synergic therapeutic effect of CDs loaded with doxorubicin against breast cancer cells is very promising. Thus, the CDs reported herein in this work have been synthesized through a green synthesis approach and can be used as a molecular probe for the detection of metal ions as well as for drug delivery applications.
Assuntos
Neoplasias da Mama , Pontos Quânticos , Humanos , Feminino , Carbono , Análise Custo-Benefício , Metais , Corantes Fluorescentes , ÍonsRESUMO
8-oxo Guanine DNA Glycosylase 1 is the initiating enzyme within base excision repair and removes oxidized guanines from damaged DNA. Since unrepaired 8-oxoG could lead to G : CâT : A transversion, base removal is of utmost importance for cells to ensure genomic integrity. For cells with elevated levels of reactive oxygen species this dependency is further increased. In the past we and others have validated OGG1 as a target for inhibitors to treat cancer and inflammation. Here, we present the optimization campaign that led to the broadly used tool compound TH5487. Based on results from a small molecule screening campaign, we performed hit to lead expansion and arrived at potent and selective substituted N-piperidinyl-benzimidazolones. Using X-ray crystallography data, we describe the surprising binding mode of the most potent member of the class, TH8535. Here, the N-Piperidinyl-linker adopts a chair instead of a boat conformation which was found for weaker analogues. We further demonstrate cellular target engagement and efficacy of TH8535 against a number of cancer cell lines.
Assuntos
DNA Glicosilases , Neoplasias , Humanos , DNA Glicosilases/química , DNA Glicosilases/genética , DNA Glicosilases/metabolismo , Guanina/química , Guanina/metabolismo , Reparo do DNA , Benzimidazóis/farmacologia , Dano ao DNARESUMO
Oxidative DNA damage is recognized by 8-oxoguanine (8-oxoG) DNA glycosylase 1 (OGG1), which excises 8-oxoG, leaving a substrate for apurinic endonuclease 1 (APE1) and initiating repair. Here, we describe a small molecule (TH10785) that interacts with the phenylalanine-319 and glycine-42 amino acids of OGG1, increases the enzyme activity 10-fold, and generates a previously undescribed ß,δ-lyase enzymatic function. TH10785 controls the catalytic activity mediated by a nitrogen base within its molecular structure. In cells, TH10785 increases OGG1 recruitment to and repair of oxidative DNA damage. This alters the repair process, which no longer requires APE1 but instead is dependent on polynucleotide kinase phosphatase (PNKP1) activity. The increased repair of oxidative DNA lesions with a small molecule may have therapeutic applications in various diseases and aging.
Assuntos
Dano ao DNA , DNA Glicosilases , Reparo do DNA , Estresse Oxidativo , Biocatálise/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , DNA Glicosilases/química , DNA Glicosilases/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Ativação Enzimática , Glicina/química , Humanos , Ligantes , Estresse Oxidativo/genética , Fenilalanina/química , Especificidade por SubstratoRESUMO
In this work, mesoporous (pore size below 4 nm) composite nanoparticles of ZnO-Ag2O/Ag, ZnO-CuO, and ZnO-SnO2 of size d ≤ 10 nm (dia.) have been synthesized through the in situ solvochemical reduction method using NaBH4. These composite nanoparticles exhibited excellent killing efficacy against Gram-positive/negative bacterial and fungal strains even at a very low dose of 0.010 µg/mL. Additionally, by applying the in silico docking approach, the nanoparticles and microorganism-specific targeted proteins and their interactions have been identified to explain the best anti-bacterial/anti-fungal activities of these composites. For this purpose, the virulence and resistance causing target proteins such as PqsR, RstA, FosA, and Hsp90 of Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, and Candida albicans have been identified to find out the best inhibitory action mechanisms involved. From the in vitro study, it is revealed that all the composite nanoparticle types used here can act as potent antimicrobial components. All the composite nanoparticles have exhibited excellent inhibition against the microorganisms compared to their constituent single metal or metal oxide nanoparticles. Among the nanoparticle types, the ZnO-Ag2O/Ag composite nanoparticles exhibited the best inhibition activity compared to the other reported nanoparticles. The microorganisms which are associated with severe infections lead to the multidrug resistance and have become a huge concern in the healthcare sector. Conventional organic antibiotics are less stable at a higher temperature. Therefore, based on the current demands, this work has been focused on designing inorganic antibiotics which possess stability even under harsh conditions. In this direction, our developed composite nanoparticles were explored for potential uses in the healthcare technology, and they may solve many problems in global emergency and epidemics caused by the microorganisms.
RESUMO
Invasive bacterial and fungal infections have notably increased the burden on the health care system and especially in immune compromised patients. These invasive bacterial and fungal species mimic and interact with the host extracellular matrix and increase the adhesion and internalization into the host system. Further, increased resistance of traditional antibiotics/antifungal drugs led to the demand for other therapeutics and preventive measures. Presently, metallic nanoparticles have wide applications in health care sectors. The present study has been designed to evaluate the advantage of Ag/Sn-SnO2 composite nanoparticles over the single oxide/metallic nanoparticles. By using in silico molecular docking approaches, herein we have evaluated the effects of Ag/Sn-SnO2 nanoparticles on adhesion and invasion responsible molecular targets such as LpfD (E. coli), Als3 (C. albicans) and on virulence/resistance causing PqsR (P. aeruginosa), RstA (Bmfr) (A. baumannii), FoxA (K. pneumonia), Hsp90 and Cyp51 (C. albicans). These Ag/Sn-SnO2 nanoparticles exhibited higher antimicrobial activities, especially against the C. albicans, which are the highest ever reported results. Further, Ag/Sn-SnO2 NPs exhibited interaction with the heme proionate residues such as Lys143, His468, Tyr132, Arg381, Phe105, Gly465, Gly464, Ile471 and Ile304 by forming hydrogen bonds with the Arg 381 residue of lanosterol 1 4α-demethylase and increased the inhibition of the Candida strains. Additionally, the Ag/Sn-SnO2 nanoparticles exhibited extraordinary inhibitory properties by targeting different proteins of bacteria and Candida species followed by several molecular pathways which indicated that it can be used to eliminate the resistance to traditional antibiotics.
RESUMO
Malaria specifically threatens health of pregnant mothers and infants and it remains unexplored in India. MiP (malaria in pregnancy) has serious short-term and long-term consequences on the mother and infant. Thus, urgent improvements in surveillance systems and management are needed to mitigate MiP as a public health problem.
Assuntos
Malária , Feminino , Humanos , Índia/epidemiologia , Lactente , Malária/diagnóstico , Mães , Avaliação das Necessidades , GravidezRESUMO
Altered oncogene expression in cancer cells causes loss of redox homeostasis resulting in oxidative DNA damage, e.g. 8-oxoguanine (8-oxoG), repaired by base excision repair (BER). PARP1 coordinates BER and relies on the upstream 8-oxoguanine-DNA glycosylase (OGG1) to recognise and excise 8-oxoG. Here we hypothesize that OGG1 may represent an attractive target to exploit reactive oxygen species (ROS) elevation in cancer. Although OGG1 depletion is well tolerated in non-transformed cells, we report here that OGG1 depletion obstructs A3 T-cell lymphoblastic acute leukemia growth in vitro and in vivo, validating OGG1 as a potential anti-cancer target. In line with this hypothesis, we show that OGG1 inhibitors (OGG1i) target a wide range of cancer cells, with a favourable therapeutic index compared to non-transformed cells. Mechanistically, OGG1i and shRNA depletion cause S-phase DNA damage, replication stress and proliferation arrest or cell death, representing a novel mechanistic approach to target cancer. This study adds OGG1 to the list of BER factors, e.g. PARP1, as potential targets for cancer treatment.
Assuntos
Neoplasias do Colo/tratamento farmacológico , DNA Glicosilases/genética , DNA de Neoplasias/genética , Regulação Neoplásica da Expressão Gênica , Poli(ADP-Ribose) Polimerase-1/imunologia , Animais , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Neoplasias do Colo/genética , Neoplasias do Colo/metabolismo , Neoplasias do Colo/mortalidade , Dano ao DNA , DNA Glicosilases/antagonistas & inibidores , DNA Glicosilases/metabolismo , Reparo do DNA/efeitos dos fármacos , Replicação do DNA/efeitos dos fármacos , DNA de Neoplasias/metabolismo , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Guanina/análogos & derivados , Guanina/metabolismo , Células HCT116 , Humanos , Camundongos , Camundongos Nus , Terapia de Alvo Molecular , Estresse Oxidativo , Poli(ADP-Ribose) Polimerase-1/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Espécies Reativas de Oxigênio/antagonistas & inibidores , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Análise de Sobrevida , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Nonhomologous DNA end joining (NHEJ) is the major DNA double-strand break (DSB) repair pathway in mammals. Previously, we have described a small molecule inhibitor, SCR7, which can inhibit NHEJ in a Ligase IV-dependent manner. Administration of SCR7 within the cells resulted in the accumulation of DNA breaks, cell death, and inhibition of tumor growth in mice. In the present study, we report that parental SCR7, which is unstable, can be autocyclized into a stable form. Both parental SCR7 and cyclized SCR7 possess the same molecular weight (334.09) and molecular formula (C18 H14 N4 OS), whereas its oxidized form, SCR7-pyrazine, possesses a different molecular formula (C18 H12 N4 OS), molecular weight (332.07), and structure. While cyclized form of SCR7 showed robust inhibition of NHEJ in vitro, both forms exhibited efficient cytotoxicity. Cyclized and oxidized forms of SCR7 inhibited DNA end joining catalyzed by Ligase IV, whereas their impact was minimal on Ligase III, Ligase I, and T4 DNA Ligase-mediated joining. Importantly, both forms inhibited V(D)J recombination, although the effect was more pronounced for SCR7-cyclized. Both forms blocked NHEJ in a Ligase IV-dependent manner leading to the accumulation of DSBs within the cells. Although cytotoxicity due to SCR7-cyclized was Ligase IV specific, the pyrazine form exhibited nonspecific cytotoxicity at higher concentrations in Ligase IV-null cells. Finally, we demonstrate that both forms can potentiate the effect of radiation. Thus, we report that cyclized and oxidized forms of SCR7 can inhibit NHEJ in a Ligase IV-dependent manner, although SCR7-pyrazine is less specific to Ligase IV inside the cell.
Assuntos
Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Reparo do DNA por Junção de Extremidades/efeitos dos fármacos , DNA Ligase Dependente de ATP/química , DNA Ligase Dependente de ATP/metabolismo , Neoplasias/patologia , Pirimidinas/farmacologia , Bases de Schiff/farmacologia , Morte Celular/efeitos dos fármacos , Células HeLa , Humanos , Células MCF-7 , Neoplasias/tratamento farmacológico , Neoplasias/genética , Oxirredução , Recombinação V(D)JRESUMO
Mutations in BLM in Bloom Syndrome patients predispose them to multiple types of cancers. Here we report that BLM is recruited in a biphasic manner to annotated DSBs. BLM recruitment is dependent on the presence of NBS1, MRE11 and ATM. While ATM activity is essential for BLM recruitment in early phase, it is dispensable in late phase when MRE11 exonuclease activity and RNF8-mediated ubiquitylation of BLM are the key determinants. Interaction between polyubiquitylated BLM and NBS1 is essential for the helicase to be retained at the DSBs. The helicase activity of BLM is required for the recruitment of HR and c-NHEJ factors onto the chromatin in S- and G1-phase, respectively. During the repair phase, BLM inhibits HR in S-phase and c-NHEJ in G1-phase. Consequently, inhibition of helicase activity of BLM enhances the rate of DNA alterations. Thus BLM utilizes its pro- and anti-repair functions to maintain genome stability.
Assuntos
Proteínas de Transporte/metabolismo , Quebras de DNA de Cadeia Dupla , Reparo do DNA por Junção de Extremidades/genética , Recombinação Homóloga/genética , Proteínas Nucleares/metabolismo , RecQ Helicases/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Síndrome de Bloom/genética , Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Proteínas de Ligação a DNA/metabolismo , Instabilidade Genômica/genética , Células HEK293 , Humanos , Proteína Homóloga a MRE11/metabolismo , Rad51 Recombinase/metabolismo , RecQ Helicases/genética , Ubiquitina-Proteína Ligases/metabolismo , UbiquitinaçãoRESUMO
Integrase inhibitors are a class of antiretroviral drugs used for the treatment of AIDS that target HIV integrase, an enzyme responsible for integration of viral cDNA into host genome. RAG1, a critical enzyme involved in V(D)J recombination exhibits structural similarity to HIV integrase. We find that two integrase inhibitors, Raltegravir and Elvitegravir, interfered with the physiological functions of RAGs such as binding, cleavage and hairpin formation at the recombination signal sequence (RSS), though the effect of Raltegravir was limited. Circular dichroism studies demonstrated a distinct change in the secondary structure of RAG1 central domain (RAG1 shares DDE motif amino acids with integrases), and when incubated with Elvitegravir, an equilibrium dissociation constant (Kd) of 32.53±2.9 µM was determined by Biolayer interferometry, leading to inhibition of its binding to DNA. Besides, using extrachromosomal assays, we show that Elvitegravir inhibited both coding and signal joint formation in pre-B cells. Importantly, treatment with Elvitegravir resulted in significant reduction of mature B lymphocytes in 70% of mice studied. Thus, our study suggests a potential risk associated with the use of Elvitegravir as an antiretroviral drug, considering the evolutionary and structural similarities between HIV integrase and RAGs.
Assuntos
Células da Medula Óssea/efeitos dos fármacos , Inibidores de Integrase de HIV/farmacologia , Proteínas de Homeodomínio/genética , Células Precursoras de Linfócitos B/efeitos dos fármacos , Quinolonas/farmacologia , Recombinação V(D)J/efeitos dos fármacos , Animais , Sítios de Ligação , Células da Medula Óssea/metabolismo , Células da Medula Óssea/virologia , Linhagem Celular , Linhagem Celular Transformada , Células HEK293 , Integrase de HIV/química , Integrase de HIV/genética , Integrase de HIV/metabolismo , Inibidores de Integrase de HIV/química , HIV-1/efeitos dos fármacos , HIV-1/enzimologia , HIV-1/genética , Proteínas de Homeodomínio/antagonistas & inibidores , Proteínas de Homeodomínio/química , Proteínas de Homeodomínio/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Mimetismo Molecular , Células Precursoras de Linfócitos B/metabolismo , Células Precursoras de Linfócitos B/virologia , Cultura Primária de Células , Ligação Proteica , Quinolonas/química , Raltegravir Potássico/química , Raltegravir Potássico/farmacologiaRESUMO
The terminal step of ligation of single and/or double-strand breaks during physiological processes such as DNA replication, repair and recombination requires participation of DNA ligases in all mammals. DNA Ligase I has been well characterised to play vital roles during these processes. Considering the indispensable role of DNA Ligase I, a therapeutic strategy to impede proliferation of cancer cells is by using specific small molecule inhibitors against it. In the present study, we have designed and chemically synthesised putative DNA Ligase I inhibitors. Based on various biochemical and biophysical screening approaches, we identify two prospective DNA Ligase I inhibitors, SCR17 and SCR21. Both the inhibitors blocked ligation of nicks on DNA in a concentration-dependent manner, when catalysed by cell-free extracts or purified Ligase I. Docking studies in conjunction with biolayer interferometry and gel shift assays revealed that both SCR17 and SCR21 can bind to Ligase I, particularly to the DNA Binding Domain of Ligase I with KD values in nanomolar range. The inhibitors did not show significant affinity towards DNA Ligase III and DNA Ligase IV. Further, addition of Ligase I could restore the joining, when the inhibitors were treated with testicular cell-free extracts. Ex vivo studies using multiple assays showed that even though cell death was limited in the presence of inhibitors in cancer cells, their proliferation was compromised. Hence, we identify two promising DNA Ligase I inhibitors, which can be used in biochemical and cellular assays, and could be further modified and optimised to target cancer cells. © 2016 Wiley Periodicals, Inc.
Assuntos
DNA Ligase Dependente de ATP/antagonistas & inibidores , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Animais , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , DNA Ligase Dependente de ATP/química , DNA Ligase Dependente de ATP/metabolismo , Replicação do DNA/efeitos dos fármacos , Desenho de Fármacos , Células HEK293 , Humanos , Masculino , Simulação de Acoplamento Molecular , Ratos , Ratos WistarRESUMO
BACKGROUND: Cancer is a multifactorial disease, which makes it difficult to cure. Since more than one defective cellular component is often involved during oncogenesis, combination therapy is gaining prominence in the field of cancer therapeutics. OBJECTIVE: The purpose of this study was to investigate the combinatorial effects of a novel PARP inhibitor, P10, and HDAC inhibitor, SAHA, in leukemic cells. METHODS: Combinatorial effects of P10 and SAHA were tested using propidium iodide staining in different leukemic cells. Further, flowcytometry-based assays such as calcein-AM/ethidium homodimer staining, annexin-FITC/PI staining, and JC-1 staining were carried out to elucidate the mechanism of cell death. In addition, cell-cycle analysis, immunocytochemistry studies, and western blotting analysis were conducted to check the combinatorial effect in Nalm6 cells. RESULTS: Propidium iodide staining showed that P10 in combination with SAHA induced cell death in Nalm6 cells, in which PARP expression and activity is high with a combination index of <0.2. Annexin-FITC/PI staining, JC-1 staining, and other biochemical assays revealed that P10 in combination with SAHA induced apoptosis by causing a change in mitochondrial membrane potential in >65 % cells. Importantly, combinatorial treatment induced S phase arrest in 40-45 % cells due to DNA damage and plausible replicative stress. Finally, we demonstrated that treatment with P10 led to DNA strand breaks, which were further potentiated by SAHA (p < 0.01), leading to activation of apoptosis and increased cell death in PARP-positive leukemic cells. CONCLUSIONS: Our study reveals that coadministration of PARP inhibitor with SAHA could be used as a combination therapy against leukemic cells that possess high levels of intrinsic PARP activity.
Assuntos
Inibidores de Histona Desacetilases/uso terapêutico , Leucemia/tratamento farmacológico , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Linhagem Celular Tumoral , Proliferação de Células , Inibidores de Histona Desacetilases/farmacologia , Humanos , Leucemia/patologia , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologiaRESUMO
DNA Ligase IV is responsible for sealing of double-strand breaks (DSBs) during nonhomologous end-joining (NHEJ). Inhibiting Ligase IV could result in amassing of DSBs, thereby serving as a strategy toward treatment of cancer. Here, we identify a molecule, SCR7 that inhibits joining of DSBs in cell-free repair system. SCR7 blocks Ligase IV-mediated joining by interfering with its DNA binding but not that of T4 DNA Ligase or Ligase I. SCR7 inhibits NHEJ in a Ligase IV-dependent manner within cells, and activates the intrinsic apoptotic pathway. More importantly, SCR7 impedes tumor progression in mouse models and when coadministered with DSB-inducing therapeutic modalities enhances their sensitivity significantly. This inhibitor to target NHEJ offers a strategy toward the treatment of cancer and improvement of existing regimens.