RESUMO
Friedreich's ataxia (FA) is due to deficiency of the mitochondrial protein, frataxin, which results in multiple pathologies including a deadly, hypertrophic cardiomyopathy. Frataxin loss leads to deleterious accumulations of redox-active, mitochondrial iron, and suppressed mitochondrial bioenergetics. Hence, there is an urgent need to develop innovative pharmaceuticals. Herein, the activity of the novel compound, 6-methoxy-2-salicylaldehyde nicotinoyl hydrazone (SNH6), was assessed in vivo using the well-characterized muscle creatine kinase (MCK) conditional frataxin knockout (KO) mouse model of FA. The design of SNH6 incorporated a dual-mechanism mediating: (1) NAD+-supplementation to restore cardiac bioenergetics; and (2) iron chelation to remove toxic mitochondrial iron. In these studies, MCK wild-type (WT) and KO mice were treated for 4-weeks from the asymptomatic age of 4.5-weeks to 8.5-weeks of age, where the mouse displays an overt cardiomyopathy. SNH6-treatment significantly elevated NAD+ and markedly increased NAD+ consumption in WT and KO hearts. In SNH6-treated KO mice, nuclear Sirt1 activity was also significantly increased together with the NAD+-metabolic product, nicotinamide (NAM). Therefore, NAD+-supplementation by SNH6 aided mitochondrial function and cardiac bioenergetics. SNH6 also chelated iron in cultured cardiac cells and also removed iron-loading in vivo from the MCK KO heart. Despite its dual beneficial properties of supplementing NAD+ and chelating iron, SNH6 did not mitigate cardiomyopathy development in the MCK KO mouse. Collectively, SNH6 is an innovative therapeutic with marked pharmacological efficacy, which successfully enhanced cardiac NAD+ and nuclear Sirt1 activity and reduced cardiac iron-loading in MCK KO mice. No other pharmaceutical yet designed exhibits both these effective pharmacological properties.
Assuntos
Aldeídos/uso terapêutico , Cardiomiopatias/tratamento farmacológico , Ataxia de Friedreich/tratamento farmacológico , Hidrazonas/uso terapêutico , Quelantes de Ferro/uso terapêutico , NAD/metabolismo , Trifosfato de Adenosina/metabolismo , Aldeídos/farmacologia , Animais , Cardiomiopatias/metabolismo , Linhagem Celular , Creatina Quinase Forma MM/genética , Modelos Animais de Doenças , Ataxia de Friedreich/metabolismo , Hidrazonas/farmacologia , Ferro/metabolismo , Quelantes de Ferro/farmacologia , Proteínas de Ligação ao Ferro/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias Cardíacas/efeitos dos fármacos , Mitocôndrias Cardíacas/metabolismo , Ratos , FrataxinaAssuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/antagonistas & inibidores , Antineoplásicos/farmacologia , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Tiossemicarbazonas/farmacologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Animais , Humanos , Lisossomos/química , Lisossomos/metabolismoRESUMO
Significance: Vitamin C or ascorbate (Asc) is a water-soluble vitamin and an antioxidant that is involved in many crucial biological functions. Asc's ability to reduce metals makes it an essential enzyme cofactor. Recent Advances: The ability of Asc to act as a reductant also plays an important part in its overall role in iron metabolism, where Asc induces both nontransferrin-bound iron and transferrin-bound iron uptake at physiological concentrations (â¼50 µM). Moreover, Asc has emerged to play an important role in multiple diseases and its effects at pharmacological doses could be important for their treatment. Critical Issues: Asc's role as a regulator of cellular iron metabolism, along with its cytotoxic effects and different roles at pharmacological concentrations, makes it a candidate as an anticancer agent. Ever since the controversy regarding the studies from the Mayo Clinic was finally explained, there has been a renewed interest in using Asc as a therapeutic approach toward cancer due to its minimal side effects. Numerous studies have been able to demonstrate the anticancer activity of Asc through selective oxidative stress toward cancer cells via H2O2 generation at pharmacological concentrations. Studies have demonstrated that Asc's cytotoxic mechanism at concentrations (>1 mM) has been associated with decreased cellular iron uptake. Future Directions: Recent studies have also suggested other mechanisms, such as Asc's effects on autophagy, polyamine metabolism, and the cell cycle. Clearly, more has yet to be discovered about Asc's mechanism of action to facilitate safe and effective treatment options for cancer and other diseases.
Assuntos
Ácido Ascórbico/metabolismo , Ferro/metabolismo , Neoplasias/metabolismo , Autofagia , Biomarcadores , Suscetibilidade a Doenças , Metabolismo Energético , Humanos , Peróxido de Hidrogênio/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/etiologia , Neoplasias/patologia , Poliaminas/metabolismoRESUMO
A series of eight bis(thiosemicarbazone) ligands and 16 of their respective copper(II) and zinc(II) complexes containing a combination of hydrogen, methyl, pyridyl, phenyl, and/or ethyl substituents at the diimine position of the ligand backbone were synthesized and characterized. The objective of this study was to identify the structure-activity relationships within a series of analogues with different substituents at the diimine position of the backbone and at the terminal N atom. The Cu(II) complexes Cu(GTSM2), Cu(GTSCM), Cu(PyTSM2), Cu(EMTSM2) and Cu(PGTSM2) demonstrated a distorted square planar geometry, while the Zn(II) complexes Zn(ATSM2)(DMSO), Zn(PyTSM2)(DMSO), and Zn(PGTSM2)(H2O) formed a distorted square pyramidal geometry. Cyclic voltammetry showed that the Cu(II) complexes display quasi-reversible electrochemistry. Of the agents, Cu(II) glyoxal bis(4,4-dimethyl-3-thiosemicarbazone) [Cu(GTSM2)] and Cu(II) diacetyl bis(4,4-dimethyl-3-thiosemicarbazone) [Cu(ATSM2)] demonstrated the greatest antiproliferative activity against tumor cells. Substitutions at the diimine position and at the terminal N atom with hydrophobic moieties markedly decreased their antiproliferative activity. Complexation of the bis(thiosemicarbazones) with Zn(II) generally decreased their antiproliferative activity, suggesting the Zn(II) complex did not act as a chaperone to deliver the ligand intracellularly, in contrast to similar bis(thiosemicarbazone) cobalt(III) complexes [King et al. Inorg. Chem. 2017, 56, 6609-6623]. However, five of the eight bis(thiosemicarbazone) Cu(II) complexes maintained or increased their antiproliferative activity, relative to the ligand alone, and a mechanism of Cu-induced oxidative stress is suggested. Surprisingly, relative to normoxic growth conditions, hypoxia that is found in the tumor microenvironment decreased the antiproliferative efficacy of most bis(thiosemicarbazones) and their copper complexes. This was independent of the potential hypoxia-selectivity mediated by Cu(II/I) redox potentials. These results provide structure-activity relationships useful for the rational design of bis(thiosemicarbazone) anticancer agents.
Assuntos
Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , Cobre/farmacologia , Tiossemicarbazonas/farmacologia , Zinco/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Cobre/química , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-Atividade , Tiossemicarbazonas/química , Células Tumorais Cultivadas , Zinco/químicaRESUMO
The mitochondrion is an essential organelle important for the generation of ATP for cellular function. This is especially critical for cells with high energy demands, such as neurons for signal transmission and cardiomyocytes for the continuous mechanical work of the heart. However, deleterious reactive oxygen species are generated as a result of mitochondrial electron transport, requiring a rigorous activation of antioxidative defense in order to maintain homeostatic mitochondrial function. Indeed, recent studies have demonstrated that the dysregulation of antioxidant response leads to mitochondrial dysfunction in human degenerative diseases affecting the nervous system and the heart. In this review, we outline and discuss the mitochondrial and oxidative stress factors causing degenerative diseases, such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, and Friedreich's ataxia. In particular, the pathological involvement of mitochondrial dysfunction in relation to oxidative stress, energy metabolism, mitochondrial dynamics, and cell death will be explored. Understanding the pathology and the development of these diseases has highlighted novel regulators in the homeostatic maintenance of mitochondria. Importantly, this offers potential therapeutic targets in the development of future treatments for these degenerative diseases.
Assuntos
Antioxidantes/metabolismo , Apoptose , Autofagia , Metabolismo Energético , Transtornos Heredodegenerativos do Sistema Nervoso/metabolismo , Mitocôndrias/metabolismo , Estresse Oxidativo , Transtornos Heredodegenerativos do Sistema Nervoso/patologia , Humanos , Mitocôndrias/patologia , Neurônios/metabolismo , Neurônios/patologia , Espécies Reativas de Oxigênio/metabolismoRESUMO
BACKGROUND: Angiogenesis is essential for tumor growth, proliferation and metastasis. Tumor-related angiogenesis is complex and involves multiple signaling pathways. Controlling angiogenesis is a promising strategy for limiting cancer progression. SCOPE OF REVIEW: Several receptor tyrosine kinases influence the angiogenic response via multiple signaling molecules and pathways. Understanding the functional interaction of kinases in the angiogenic process and development of resistance to kinase inhibition is essential for future successful therapeutic strategies. MAJOR CONCLUSIONS: Strategies that target receptor tyrosine kinases and other tumor microenvironment factors simultaneously, or sequentially, are required for achieving an efficient and robust anti-angiogenic response. GENERAL SIGNIFICANCE: Understanding the molecular mechanism of angiogenesis has improved, and has led, to the clinical development and approval of anti-angiogenic drugs. While many patients have benefited from these agents, their limited efficacy and the development of resistance remains a challenge. This review highlights current therapies and challenges associated with targeting angiogenesis in cancer.
Assuntos
Neoplasias/irrigação sanguínea , Neovascularização Patológica , Receptores Proteína Tirosina Quinases/metabolismo , Resistencia a Medicamentos Antineoplásicos , Humanos , Neoplasias/enzimologiaRESUMO
Solid-phase microextraction (SPME) is an alternative method to dialysis and ultrafiltration for the determination of plasma protein binding (PPB) of drugs. It is particularly advantageous for complicated analytes where standard methods are not applicable. Di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC) is a lead compound of novel thiosemicarbazone anti-cancer drugs, which entered clinical trials in 2016. However, this agent exhibited non-specific binding on filtration membranes and had intrinsic chelation activity, which precluded standard PPB methods. In this study, using a simple and fast procedure, we prepared novel SPME fibers for extraction of DpC based on a metal-free, silicon string support, covered with C18 sorbent. Reproducibility of the preparation process was demonstrated by the percent relative standard deviation (RSD) of ≤ 9.2% of the amount of DpC extracted from PBS by several independently prepared fibers. The SPME procedure was optimized by evaluating extraction and desorption time profiles. Suitability of the optimized protocol was verified by examining reproducibility, linearity, and recovery of DpC extracted from PBS or plasma. All samples extracted by SPME were analyzed using an optimized and validated UHPLC-MS/MS method. The developed procedure was applied to the in vitro determination of PPB of DpC at two clinically relevant concentrations (500 and 1000 ng/mL). These studies showed that DpC is highly bound to plasma proteins (PPB ≥ 88%) and this did not differ significantly between both concentrations tested. This investigation provides novel data in the applicability of SPME for the determination of PPB of chelators, as well as useful information for the clinical development of DpC. Graphical abstract.
Assuntos
Antineoplásicos/metabolismo , Proteínas Sanguíneas/metabolismo , Piridinas/metabolismo , Microextração em Fase Sólida/instrumentação , Tiossemicarbazonas/metabolismo , Adsorção , Animais , Bovinos , Cromatografia Líquida de Alta Pressão/métodos , Desenho de Equipamento , Ligação Proteica , Ratos , Silício/química , Microextração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodosRESUMO
Metals are vital cellular elements necessary for multiple indispensable biological processes of living organisms, including energy transduction and cell proliferation. Interestingly, alterations in metal levels and also changes in the expression of proteins involved in metal metabolism have been demonstrated in a variety of cancers. Considering this and the important role of metals for cell growth, the development of drugs that sequester metals has become an attractive target for the development of novel anti-cancer agents. Interest in this field has surged with the design and development of new generations of chelators of the thiosemicarbazone class. These ligands have shown potent anticancer and anti-metastatic activity in vitro and in vivo. Due to their efficacy and safe toxicological assessment, some of these agents have recently entered multi-center clinical trials as therapeutics for advanced and resistant tumors. This review highlights the role and changes in homeostasis of metals in cancer and emphasizes the pre-clinical development and clinical assessment of metal ion-binding agents, namely, thiosemicarbazones, as antitumor agents.
Assuntos
Antineoplásicos/uso terapêutico , Quelantes/uso terapêutico , Metais Pesados/metabolismo , Neoplasias/tratamento farmacológico , Tiossemicarbazonas/uso terapêutico , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Quelantes/química , Quelantes/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Humanos , Ligantes , Metais Pesados/química , Metástase Neoplásica/prevenção & controle , Neoplasias/metabolismo , Tiossemicarbazonas/química , Tiossemicarbazonas/farmacologiaRESUMO
Alzheimer's disease (AD) is characterized by multiple pathological hallmarks, including ß-amyloid aggregation, oxidative stress, and metal dys-homeostasis. In the absence of treatments addressing its multi-factorial pathology, we designed novel multi-functional adamantane-based semicarbazones and hydrazones (1-12) targeting AD hallmarks. Of these, 2-pyridinecarboxaldehyde (N-adamantan-1-yl)benzoyl-4-amidohydrazone (10) was identified as the lead compound, which demonstrated: (1) pronounced iron chelation efficacy; (2) attenuation of CuII-mediated ß-amyloid aggregation; (3) low cytotoxicity; (4) inhibition of oxidative stress; and (5) favorable characteristics for effective blood-brain barrier permeation. Structure-activity relationships revealed that pyridine-derived hydrazones represent a promising pharmacophore for future design strategies due to their ability to bind critical FeII pools. Collectively, the unique multi-functional activity of these agents provides a novel therapeutic strategy for AD treatment.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/antagonistas & inibidores , Antineoplásicos/farmacologia , Quelantes/farmacologia , Compostos Organometálicos/farmacologia , Adamantano/química , Adamantano/farmacologia , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Quelantes/síntese química , Quelantes/química , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Hidrazonas/química , Hidrazonas/farmacologia , Modelos Moleculares , Estrutura Molecular , Compostos Organometálicos/síntese química , Compostos Organometálicos/química , Estresse Oxidativo/efeitos dos fármacos , Agregados Proteicos/efeitos dos fármacos , Semicarbazonas/química , Semicarbazonas/farmacologiaRESUMO
The metastasis suppressor, N-myc downstream regulated gene-1 (NDRG1), exhibits pleiotropic activity, inhibiting metastasis of various tumor-types, while being correlated with metastasis in others. Notably, NDRG1 phosphorylation and cleavage are associated with its function, although it is unclear if these modifications occur universally, or selectively, in different cancer cell-types and if it contributes to its pleiotropy. Considering the suggested DNA repair role of nuclear NDRG1, the effects of the above post-translational modifications on its nuclear localization was examined. Herein, the full-length (FL) and truncated (T) NDRG1 isoforms were detected using a C-terminus-directed antibody, while only the FL isoform was identified using an N-terminus-directed antibody. For the first time, we demonstrate that the expression of the NDRG1 FL and T forms occurs in all cancer cell-types examined, as does its phosphorylation (p-NDRG1) at Ser330 and Thr346. The FL isoform localized highly in the nucleus compared to the T isoform. Moreover, p-NDRG1 (Ser330) was also markedly localized in the nucleus, while p-NDRG1 (Thr346) was predominantly cytoplasmic in all cell-types. These results indicate the N-terminus region and phosphorylation at Ser330 could be crucial for NDRG1 nuclear localization and function. PTEN silencing indicated that p-NDRG1 (Thr346) could be regulated differentially in different tumor cell-types, indicating PTEN may be involved in the mechanism(s) underlying the pleiotropic activity of NDRG1. Finally, therapeutics of the di-2-pyridylketone thiosemicarbazone class increased nuclear NDRG1 isoforms (FL and T) detected by the C-terminus-directed antibody in HepG2 cells, while having no significant effect in PC3 cells, indicating differential activity depending on the cell-type.
Assuntos
Proteínas de Ciclo Celular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , PTEN Fosfo-Hidrolase/metabolismo , Neoplasias da Próstata/metabolismo , Proteínas de Ciclo Celular/genética , Células Hep G2 , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Metástase Neoplásica , PTEN Fosfo-Hidrolase/genética , Fosforilação/genética , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Transporte Proteico/genéticaRESUMO
Mitochondrial homeostasis is essential for maintaining healthy cellular function and survival. The detrimental involvement of mitochondrial dysfunction in neuro-degenerative diseases has recently been highlighted in human conditions, such as Parkinson's, Alzheimer's and Huntington's disease. Friedreich's ataxia (FA) is another neuro-degenerative, but also cardio-degenerative condition, where mitochondrial dysfunction plays a crucial role in disease progression. Deficient expression of the mitochondrial protein, frataxin, is the primary cause of FA, which leads to adverse alterations in whole cell and mitochondrial iron metabolism. Dys-regulation of iron metabolism in these compartments, results in the accumulation of inorganic iron deposits in the mitochondrial matrix that is thought to potentiate oxidative damage observed in FA. Therefore, the maintenance of mitochondrial homeostasis is crucial in the progression of neuro-degenerative conditions, particularly in FA. In this review, vital mitochondrial homeostatic processes and their roles in FA pathogenesis will be discussed. These include mitochondrial iron processing, mitochondrial dynamics (fusion and fission processes), mitophagy, mitochondrial biogenesis, mitochondrial energy production and calcium metabolism.
Assuntos
Doenças Cardiovasculares/metabolismo , Ataxia de Friedreich/metabolismo , Mitocôndrias/metabolismo , Doenças Neurodegenerativas/metabolismo , Animais , Doenças Cardiovasculares/genética , Doenças Cardiovasculares/patologia , Ataxia de Friedreich/genética , Ataxia de Friedreich/patologia , Homeostase/fisiologia , Humanos , Proteínas de Ligação ao Ferro/genética , Proteínas de Ligação ao Ferro/metabolismo , Mitocôndrias/genética , Mitocôndrias/patologia , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/patologia , Estresse Oxidativo/fisiologia , FrataxinaRESUMO
Over 44 million people live with Alzheimer's disease (AD) worldwide. Currently, only symptomatic treatments are available for AD and no cure exists. Considering the lack of effective treatments for AD due to its multi-factorial pathology, development of novel multi-target-directed drugs are desirable. Herein, we report the development of a novel series of thiosemicarbazones derived from 1-benzylpiperidine, a pharmacophore within the acetylcholinesterase inhibitor, Donepezil. These thiosemicarbazones were designed to target five major AD hallmarks, including: low acetylcholine levels, dysfunctional autophagy, metal dys-homeostasis, protein aggregation and oxidative stress. Of these thiosemicarbazones, pyridoxal 4-N-(1-benzylpiperidin-4-yl)thiosemicarbazone (PBPT) emerged as the lead compound. This agent demonstrated the most promising multi-functional activity by exhibiting very low anti-proliferative activity, substantial iron chelation efficacy, inhibition of copper-mediated amyloid-ß aggregation, inhibition of oxidative stress, moderate acetylcholinesterase inhibitory activity and autophagic induction. These diverse properties highlight the potential of the lead ligand, PBPT, as a promising multi-functional agent for AD treatment.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Tiossemicarbazonas/farmacologia , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Humanos , Peróxido de Hidrogênio/antagonistas & inibidores , Peróxido de Hidrogênio/farmacologia , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-Atividade , Tiossemicarbazonas/síntese química , Tiossemicarbazonas/química , Células Tumorais CultivadasRESUMO
Tumor necrosis factor α (TNFα) plays a vital role in cancer progression as it is associated with inflammation and promotion of cancer angiogenesis and metastasis. The effects of TNFα are mediated by its downstream target, the oncogene lysine-rich CEACAM1 coisolated protein (LYRIC, also known as metadherin or astrocyte elevated gene-1). LYRIC plays an important role in activating the nuclear factor-ĸB (NF-κB) signaling pathway, which controls multiple cellular processes, including proliferation, apoptosis, migration, etc. In contrast, the metastasis suppressor N-myc downstream regulated gene 1 (NDRG1) has the opposite effect on the NF-κB pathway, being able to inhibit NF-κB activation and reduce angiogenesis, proliferation, migration, and cancer cell invasion. These potent anticancer properties make NDRG1 an ideal therapeutic target. Indeed, a novel class of thiosemicarbazone anticancer agents that target this molecule has been developed; the lead agent, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone, has recently entered clinical trials for advanced and resistant cancers. To further elucidate the interaction between NDRG1 and oncogenic signaling, this study for the first time assessed the effects of NDRG1 on the tumorigenic properties of TNFα and its downstream target, LYRIC. We have demonstrated that NDRG1 inhibits the TNFα-mediated epithelial-to-mesenchymal transition. Further, NDRG1 also potently inhibited LYRIC expression, with a negative feedback loop existing between these two molecules. Examining the mechanism involved, we demonstrated that NDRG1 inhibited phosphatidylinositol 3-kinase/AKT signaling, leading to reduced levels of the LYRIC transcriptional activator, c-Myc. Finally, we demonstrated that novel thiosemicarbazones that upregulate NDRG1 also inhibit LYRIC expression, further highlighting their marked potential for cancer treatment.
Assuntos
Moléculas de Adesão Celular/metabolismo , Proteínas de Ciclo Celular/metabolismo , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Tiossemicarbazonas/farmacologia , Regulação para Cima/efeitos dos fármacos , Linhagem Celular Tumoral , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Desferroxamina/farmacologia , Inativação Gênica/efeitos dos fármacos , Humanos , Proteínas de Membrana , Modelos Biológicos , NF-kappa B/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Transporte Proteico/efeitos dos fármacos , Proteínas de Ligação a RNA , Tiossemicarbazonas/química , Fator de Necrose Tumoral alfa/farmacologia , Vimentina/metabolismoRESUMO
n/a.
Assuntos
Antineoplásicos/farmacologia , DNA/metabolismo , Albumina Sérica/metabolismo , Tiossemicarbazonas/farmacologia , Antineoplásicos/metabolismo , Proliferação de Células/efeitos dos fármacos , Dicroísmo Circular , Publicações Duplicadas como Assunto , Células Hep G2 , Humanos , Tiossemicarbazonas/metabolismoRESUMO
BACKGROUND: Neuroblastoma is a relatively common and highly belligerent childhood tumor with poor prognosis by current therapeutic approaches. A novel anti-cancer agent of the di-2-pyridylketone thiosemicarbazone series, namely di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), demonstrates promising anti-tumor activity. Recently, a second-generation analogue, namely di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC), has entered multi-center clinical trials for the treatment of advanced and resistant tumors. The current aim was to examine if these novel agents were effective against aggressive neuroblastoma in vitro and in vivo and to assess their mechanism of action. METHODS: Neuroblastoma cancer cells as well as immortalized normal cells were used to assess the efficacy and selectivity of DpC in vitro. An orthotopic SK-N-LP/Luciferase xenograft model was used in nude mice to assess the efficacy of DpC in vivo. Apoptosis in tumors was confirmed by Annexin V/PI flow cytometry and H&E staining. RESULTS: DpC demonstrated more potent cytotoxicity than Dp44mT against neuroblastoma cells in a dose- and time-dependent manner. DpC significantly increased levels of phosphorylated JNK, neuroglobin, cytoglobin, and cleaved caspase 3 and 9, while decreasing IkBα levels in vitro. The contribution of JNK, NF-ĸB, and caspase signaling/activity to the anti-tumor activity of DpC was verified by selective inhibitors of these pathways. After 3 weeks of treatment, tumor growth in mice was significantly (p < 0.05) reduced by DpC (4 mg/kg/day) given intravenously and the agent was well tolerated. Xenograft tissues showed significantly higher expression of neuroglobin, cytoglobin, caspase 3, and tumor necrosis factor-α (TNFα) levels and a slight decrease in interleukin-10 (IL-10). CONCLUSIONS: DpC was found to be highly potent against neuroblastoma, demonstrating its potential as a novel therapeutic for this disease. The ability of DpC to increase TNFα in tumors could also promote the endogenous immune response to mediate enhanced cancer cell apoptosis.
RESUMO
Multidrug resistance (MDR) mediated by P-glycoprotein (Pgp) represents a significant impediment to successful cancer treatment. The compound, di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), has been shown to induce greater cytotoxicity against resistant cells than their nonresistant counterparts. Herein, the structure-activity relationships of selected thiosemicarbazones are explored and the novel mechanism underlying their ability to overcome resistance is further elucidated. Only thiosemicarbazones with electron-withdrawing substituents at the imine carbon mediated Pgp-dependent potentiated cytotoxicity, which was reversed by Pgp inhibition. Treatment of resistant cells with these thiosemicarbazones resulted in Pgp-dependent lysosomal membrane permeabilization (LMP) that relied on copper (Cu) chelation, reactive oxygen species generation, and increased relative lipophilicity. Hence, this study is the first to demonstrate the structural requirements of these thiosemicarbazones necessary to overcome MDR. We also demonstrate the mechanism that enables the targeting of resistant tumors, whereby thiosemicarbazones "hijack" lysosomal Pgp and form redox-active Cu complexes that mediate LMP and potentiate cytotoxicity.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Antineoplásicos/química , Antineoplásicos/farmacologia , Tiossemicarbazonas/química , Tiossemicarbazonas/farmacologia , Linhagem Celular Tumoral , Cobre/metabolismo , Resistência a Múltiplos Medicamentos , Humanos , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Lisossomos/patologia , Modelos Moleculares , Permeabilidade/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Relação Estrutura-AtividadeRESUMO
Cancer is a leading cause of death in many countries around the world. However, the efficacy of current standard treatments for a variety of cancers is suboptimal. First, most cancer treatments lack specificity, meaning that these treatments affect both cancer cells and their normal counterparts. Second, many anticancer agents are highly toxic, and thus, limit their use in treatment. Third, a number of cytotoxic chemotherapeutics are highly hydrophobic, which limits their utility in cancer therapy. Finally, many chemotherapeutic agents exhibit short half-lives that curtail their efficacy. As a result of these deficiencies, many current treatments lead to side effects, noncompliance, and patient inconvenience due to difficulties in administration. However, the application of nanotechnology has led to the development of effective nanosized drug delivery systems known commonly as nanoparticles. Among these delivery systems, lipid-based nanoparticles, particularly liposomes, have shown to be quite effective at exhibiting the ability to: 1) improve the selectivity of cancer chemotherapeutic agents; 2) lower the cytotoxicity of anticancer drugs to normal tissues, and thus, reduce their toxic side effects; 3) increase the solubility of hydrophobic drugs; and 4) offer a prolonged and controlled release of agents. This review will discuss the current state of lipid-based nanoparticle research, including the development of liposomes for cancer therapy, different strategies for tumor targeting, liposomal formulation of various anticancer drugs that are commercially available, recent progress in liposome technology for the treatment of cancer, and the next generation of lipid-based nanoparticles.
Assuntos
Antineoplásicos/administração & dosagem , Sistemas de Liberação de Medicamentos/métodos , Lipossomos/administração & dosagem , Nanopartículas/administração & dosagem , Neoplasias/tratamento farmacológico , Antineoplásicos/efeitos adversos , Composição de Medicamentos/métodos , HumanosRESUMO
Copper is an essential trace metal required by organisms to perform a number of important biological processes. Copper readily cycles between its reduced Cu(i) and oxidised Cu(ii) states, which makes it redox active in biological systems. This redox-cycling propensity is vital for copper to act as a catalytic co-factor in enzymes. While copper is essential for normal physiology, enhanced copper levels in tumours leads to cancer progression. In particular, the stimulatory effect of copper on angiogenesis has been established in the last several decades. Additionally, it has been demonstrated that copper affects tumour growth and promotes metastasis. Based on the effects of copper on cancer progression, chelators that bind copper have been developed as anti-cancer agents. In fact, a novel class of thiosemicarbazone compounds, namely the di-2-pyridylketone thiosemicarbazones that bind copper, have shown great promise in terms of their anti-cancer activity. These agents have a unique mechanism of action, in which they form redox-active complexes with copper in the lysosomes of cancer cells. Furthermore, these agents are able to overcome P-glycoprotein (P-gp) mediated multi-drug resistance (MDR) and act as potent anti-oncogenic agents through their ability to up-regulate the metastasis suppressor protein, N-myc downstream regulated gene-1 (NDRG1). This review provides an overview of the metabolism and regulation of copper in normal physiology, followed by a discussion of the dysregulation of copper homeostasis in cancer and the effects of copper on cancer progression. Finally, recent advances in our understanding of the mechanisms of action of anti-cancer agents targeting copper are discussed.
Assuntos
Antineoplásicos/farmacologia , Cobre/química , Neoplasias/tratamento farmacológico , Tiossemicarbazonas/farmacologia , Animais , Antineoplásicos/química , Cobre/metabolismo , Humanos , Tiossemicarbazonas/químicaAssuntos
Antineoplásicos/farmacologia , Autofagia/efeitos dos fármacos , Proteínas de Ciclo Celular/antagonistas & inibidores , Desenho de Fármacos , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Lisossomos/efeitos dos fármacos , Neoplasias/tratamento farmacológico , Tiossemicarbazonas/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Proteínas de Ciclo Celular/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Lisossomos/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , Tiossemicarbazonas/síntese química , Tiossemicarbazonas/química , Microambiente Tumoral/efeitos dos fármacosRESUMO
The potent and selective anti-tumor agent, di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), localizes in lysosomes and forms cytotoxic copper complexes that generate reactive oxygen species (ROS), resulting in lysosomal membrane permeabilization (LMP) and cell death. Herein, the role of lysosomal membrane stability in the anti-tumor activity of Dp44mT was investigated. Studies were performed using molecules that protect lysosomal membranes against Dp44mT-induced LMP, namely heat shock protein 70 (HSP70) and cholesterol. Up-regulation or silencing of HSP70 expression did not affect Dp44mT-induced LMP in MCF7 cells. In contrast, cholesterol accumulation in lysosomes induced by the well characterized cholesterol transport inhibitor, 3-ß-[2-(diethyl-amino)ethoxy]androst-5-en-17-one (U18666A), inhibited Dp44mT-induced LMP and markedly and significantly (p<0.001) reduced the ability of Dp44mT to inhibit cancer cell proliferation (i.e., increased the IC(50)) by 140-fold. On the other hand, cholesterol extraction using methyl-ß-cyclodextrin enhanced Dp44mT-induced LMP and significantly (p<0.01) increased its anti-proliferative activity. The protective effect of U18666A in increasing lysosomal cholesterol and preventing the cytotoxic activity of Dp44mT was not due to induced autophagy. Instead, U18666A was found to decrease lysosomal turnover, resulting in autophagosome accumulation. Moreover, preincubation with U18666A did not prevent the ability of Dp44mT to induce autophagosome synthesis, indicating that autophagic initiation via Dp44mT occurs independently of LMP. These studies demonstrate the significance of lysosomal membrane stability in relation to the ability of Dp44mT to execute tumor cell death and overcome pro-survival autophagy. Hence, lysosomal-dependent cell death induced by Dp44mT serves as an important anti-tumor strategy. These results are important for comprehensively understanding the mechanism of action of Dp44mT.