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1.
Anticancer Agents Med Chem ; 23(19): 2111-2126, 2023.
Article in English | MEDLINE | ID: mdl-37287303

ABSTRACT

BACKGROUND: Thyroid carcinoma (THCA) is one of the most prevalent endocrine tumors, accounting for 3.4% of all cancers diagnosed annually. Single Nucleotide Polymorphisms (SNPs) are the most prevalent genetic variation associated with thyroid cancer. Understanding thyroid cancer genetics will enhance diagnosis, prognosis, and treatment. METHODS: This TCGA-based study analyzes thyroid cancer-associated highly mutated genes through highly robust in silico techniques. Pathway, gene expression, and survival studies were performed on the top 10 highly mutated genes (BRAF, NRAS, TG, TTN, HRAS, MUC16, ZFHX3, CSMD2, EIFIAX, SPTA1). Novel natural compounds from Achyranthes aspera Linn were discovered to target two highly mutated genes. The natural compounds and synthetic drugs used to treat thyroid cancer were subjected to comparative molecular docking against BRAF and NRAS targets. The ADME characteristics of Achyranthes aspera Linn compounds were also investigated. RESULTS: The gene expression analysis revealed that the expression of ZFHX3, MCU16, EIF1AX, HRAS, and NRAS was up-regulated in tumor cells while BRAF, TTN, TG, CSMD2, and SPTA1 were down-regulated in tumor cells. In addition, the protein-protein interaction network demonstrated that HRAS, BRAF, NRAS, SPTA1, and TG proteins have strong interactions with each other as compared to other genes. The ADMET analysis shows that seven compounds have druglike properties. These compounds were further studied for molecular docking studies. The compounds MPHY012847, IMPHY005295, and IMPHY000939 show higher binding affinity with BRAF than pimasertib. In addition, IMPHY000939, IMPHY000303, IMPHY012847, and IMPHY005295 showed a better binding affinity with NRAS than Guanosine Triphosphate. CONCLUSION: The outcomes of docking experiments conducted on BRAF and NRAS provide insight into natural compounds with pharmacological characteristics. These findings indicate that natural compounds derived from plants as a more promising cancer treatment option. Thus, the results of docking investigations conducted on BRAF and NRAS substantiate the conclusions that the molecule possesses the most suited drug-like qualities. Compared to other compounds, natural compounds are superior, and they are also druggable. This demonstrates that natural plant compounds can be an excellent source of potential anti-cancer agents. The preclinical research will pave the road for a possible anti-cancer agent.


Subject(s)
Achyranthes , GTP Phosphohydrolases , Membrane Proteins , Proto-Oncogene Proteins B-raf , Thyroid Neoplasms , Humans , Achyranthes/chemistry , GTP Phosphohydrolases/antagonists & inhibitors , Membrane Proteins/antagonists & inhibitors , Molecular Docking Simulation , Mutation , Proto-Oncogene Proteins B-raf/antagonists & inhibitors , Thyroid Neoplasms/drug therapy , Thyroid Neoplasms/genetics , Thyroid Neoplasms/metabolism , Phytochemicals/pharmacology
2.
Antimicrob Agents Chemother ; 66(1): e0149821, 2022 01 18.
Article in English | MEDLINE | ID: mdl-34723630

ABSTRACT

Malaria accounts for millions of cases and thousands of deaths every year. In the absence of an effective vaccine, drugs are still the most important tool in the fight against the disease. Plasmodium parasites developed resistance to all classes of known antimalarial drugs. Thus, the search for antimalarial drugs with novel mechanisms of action is compelling. The human GTPase Rac1 plays a role in parasite invasion of the host cell in many intracellular pathogens. Also, in Plasmodium falciparum, the involvement of Rac1 during both the invasion process and parasite intracellular development was suggested. The aim of this work is to test a panel of Rac1 inhibitors as potential antimalarial drugs. Fourteen commercially available or newly synthesized inhibitors of Rac1 were tested for antimalarial activity. Among these, EHop-016 was the most effective against P. falciparum in vitro, with nanomolar 50% inhibitory concentrations (IC50s) (138.8 ± 16.0 nM on the chloroquine-sensitive D10 strain and 321.5 ± 28.5 nM on the chloroquine-resistant W2 strain) and a selectivity index of 37.8. EHop-016 did not inhibit parasite invasion of red blood cells but affected parasite growth inside them. Among the tested Rac1 inhibitors, EHop-016 showed promising activity that raises attention to this class of molecules as potential antimalarials and deserves further investigation.


Subject(s)
Antimalarials , GTP Phosphohydrolases , Malaria, Falciparum , rac1 GTP-Binding Protein , Antimalarials/pharmacology , Antimalarials/therapeutic use , Chloroquine/pharmacology , Chloroquine/therapeutic use , GTP Phosphohydrolases/antagonists & inhibitors , Humans , Malaria, Falciparum/drug therapy , Plasmodium falciparum , rac1 GTP-Binding Protein/antagonists & inhibitors
3.
Biomolecules ; 11(8)2021 07 30.
Article in English | MEDLINE | ID: mdl-34439794

ABSTRACT

Recent breakthroughs have reignited interest in RAS GEFs as direct therapeutic targets. To search for new inhibitors of SOS GEF activity, a repository of known/approved compounds (NIH-NACTS) and a library of new marine compounds (Biomar Microbial Technologies) were screened by means of in vitro RAS-GEF assays using purified, bacterially expressed SOS and RAS constructs. Interestingly, all inhibitors identified in our screenings (two per library) shared related chemical structures belonging to the anthraquinone family of compounds. All our anthraquinone SOS inhibitors were active against the three canonical RAS isoforms when tested in our SOS GEF assays, inhibited RAS activation in mouse embryonic fibroblasts, and were also able to inhibit the growth of different cancer cell lines harboring WT or mutant RAS genes. In contrast to the commercially available anthraquinone inhibitors, our new marine anthraquinone inhibitors did not show in vivo cardiotoxicity, thus providing a lead for future discovery of stronger, clinically useful anthraquinone SOS GEF blockers.


Subject(s)
Anthraquinones/pharmacology , Antineoplastic Agents/pharmacology , GTP Phosphohydrolases/antagonists & inhibitors , Membrane Proteins/antagonists & inhibitors , Proto-Oncogene Proteins p21(ras)/antagonists & inhibitors , Small Molecule Libraries/pharmacology , Animals , Cardiotoxicity/prevention & control , Cell Line, Transformed , Cell Line, Tumor , Doxorubicin/pharmacology , Epithelial Cells/drug effects , Epithelial Cells/metabolism , Epithelial Cells/pathology , Fibroblasts/cytology , Fibroblasts/drug effects , Fibroblasts/metabolism , GTP Phosphohydrolases/genetics , GTP Phosphohydrolases/metabolism , Humans , Idarubicin/pharmacology , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice , Mice, Knockout , Proto-Oncogene Proteins p21(ras)/genetics , Proto-Oncogene Proteins p21(ras)/metabolism , SOS1 Protein/genetics , SOS1 Protein/metabolism , Son of Sevenless Proteins/deficiency , Son of Sevenless Proteins/genetics
4.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1866(12): 159030, 2021 12.
Article in English | MEDLINE | ID: mdl-34419589

ABSTRACT

In the liver, contact sites between the endoplasmic reticulum (ER) and mitochondria (named MAMs) may be crucial hubs for the regulation of lipid metabolism, thus contributing to the exacerbation or prevention of fatty liver. We hypothesized that tether proteins located at MAMs could play a key role in preventing triglyceride accumulation in hepatocytes and nonalcoholic fatty liver disease (NAFLD) occurrence. To test this, we explored the role of two key partners in building MAM integrity and functionality, the glucose-regulated protein 75 (Grp75) and mitofusin 2 (Mfn2), which liver contents are altered in obesity and NAFLD. Grp75 or Mfn2 expression was either silenced using siRNA or overexpressed with adenoviruses in Huh7 cells. Silencing of Grp75 and Mfn2 resulted in decreased ER-mitochondria interactions, mitochondrial network fusion state and mitochondrial oxidative capacity, while overexpression of the two proteins induced mirror impacts on these parameters. Furthermore, Grp75 or Mfn2 silencing decreased cellular cholesterol content and enhanced triglyceride secretion in ApoB100 lipoproteins, while their overexpression led to reverse effects. Cellular phosphatidylcholine/phosphatidylethanolamine ratio was decreased only upon overexpression of the proteins, potentially contributing to altered ApoB100 assembly and secretion. Despite the opposite differences, both silencing and overexpression of Grp75 or Mfn2 induced triglyceride storage, although a fatty acid challenge was required to express the alteration upon protein silencing. Among the mechanisms potentially involved in this phenotype, ER stress was closely associated with altered triglyceride metabolism after Grp75 or Mfn2 overexpression, while blunted mitochondrial FA oxidation capacity may be the main defect causing triglyceride accumulation upon Grp75 or Mfn2 silencing. Further studies are required to decipher the link between modulation of Grp75 or Mfn2 expression, change in MAM integrity and alteration of cholesterol content of the cell. In conclusion, Grp75 or Mfn2 silencing and overexpression in Huh7 cells contribute to altering MAM integrity and cholesterol storage in opposite directions, but all promote triglyceride accumulation through distinct cellular pathways. This study also highlights that besides Mfn2, Grp75 could play a central role in hepatic lipid and cholesterol metabolism in obesity and NAFLD.


Subject(s)
Apolipoprotein B-100/genetics , Cholesterol/metabolism , GTP Phosphohydrolases/genetics , HSP70 Heat-Shock Proteins/genetics , Mitochondrial Proteins/genetics , Non-alcoholic Fatty Liver Disease/genetics , Cell Line , Endoplasmic Reticulum/genetics , Endoplasmic Reticulum/metabolism , GTP Phosphohydrolases/antagonists & inhibitors , Gain of Function Mutation/genetics , Gene Expression Regulation/genetics , Gene Silencing , HSP70 Heat-Shock Proteins/antagonists & inhibitors , Hepatocytes/metabolism , Humans , Liver/metabolism , Loss of Function Mutation/genetics , Mitochondria/genetics , Mitochondria/metabolism , Mitochondrial Proteins/antagonists & inhibitors , Non-alcoholic Fatty Liver Disease/metabolism , Non-alcoholic Fatty Liver Disease/pathology , Triglycerides/metabolism
5.
Med Clin North Am ; 105(4): 643-661, 2021 Jul.
Article in English | MEDLINE | ID: mdl-34059243

ABSTRACT

Melanoma accounts for approximately 1% of all skin cancers but contributes to almost all skin cancer deaths. The developing picture suggests that melanoma phenotypes are driven by epigenetic mechanisms that reflect a complex interplay between genotype and environment. Furthermore, the growing consensus is that current classification standards, notwithstanding pertinent clinical history and appropriate biopsy, fall short of capturing the vast complexity of the disease. This article summarizes the current understanding of the clinical picture of melanoma, with a focus on the tremendous breakthroughs in molecular classification and therapeutics.


Subject(s)
Melanoma/diagnosis , Melanoma/genetics , Neoplasm Staging/methods , Skin Neoplasms/genetics , Skin Neoplasms/pathology , Aged , Biopsy , Drug Therapy/methods , Epigenesis, Genetic/genetics , Female , GTP Phosphohydrolases/antagonists & inhibitors , Genotype , Humans , Immunotherapy/methods , Incidence , Male , Melanoma/epidemiology , Melanoma/therapy , Membrane Proteins/antagonists & inhibitors , Mohs Surgery/methods , Molecular Targeted Therapy/methods , Mutation/genetics , Proto-Oncogene Proteins B-raf/antagonists & inhibitors , Skin Neoplasms/ethnology , Skin Neoplasms/mortality , United States/epidemiology , Young Adult
6.
Development ; 148(5)2021 03 09.
Article in English | MEDLINE | ID: mdl-33547132

ABSTRACT

The Hedgehog (Hh) morphogen gradient is required for patterning during metazoan development, yet the mechanisms involved in Hh apical and basolateral release and how this influences short- and long-range target induction are poorly understood. We found that depletion of the GTPase Rab8 in Hh-producing cells induces an imbalance between the level of apically and laterally released Hh. This leads to non-cell-autonomous differential effects on the expression of Hh target genes, namely an increase in its short-range targets and a concomitant decrease in long-range targets. We further found that Rab8 regulates the endocytosis and apico-basal distribution of Ihog, a transmembrane protein known to bind to Hh and to be crucial for establishment of the Hh gradient. Our data provide new insights into morphogen gradient formation, whereby morphogen activity is functionally distributed between apically and basolaterally secreted pools.


Subject(s)
Drosophila Proteins/metabolism , Drosophila/metabolism , GTP Phosphohydrolases/metabolism , Hedgehog Proteins/metabolism , Animals , Animals, Genetically Modified/metabolism , Drosophila Proteins/antagonists & inhibitors , Drosophila Proteins/genetics , Endocytosis , Endosomes/metabolism , GTP Phosphohydrolases/antagonists & inhibitors , GTP Phosphohydrolases/genetics , Gene Expression Regulation , Hedgehog Proteins/genetics , Membrane Glycoproteins/genetics , Membrane Glycoproteins/metabolism , Mutagenesis , Protein Stability , RNA Interference , RNA, Double-Stranded/metabolism , Receptors, Cell Surface/genetics , Receptors, Cell Surface/metabolism , Signal Transduction
7.
Hum Mol Genet ; 29(22): 3631-3645, 2021 01 21.
Article in English | MEDLINE | ID: mdl-33231680

ABSTRACT

OPA1 mutations are the major cause of dominant optic atrophy (DOA) and the syndromic form DOA plus, pathologies for which there is no established cure. We used a 'drug repurposing' approach to identify FDA-approved molecules able to rescue the mitochondrial dysfunctions induced by OPA1 mutations. We screened two different chemical libraries by using two yeast strains carrying the mgm1I322M and the chim3P646L mutations, identifying 26 drugs able to rescue their oxidative growth phenotype. Six of them, able to reduce the mitochondrial DNA instability in yeast, have been then tested in Opa1 deleted mouse embryonic fibroblasts expressing the human OPA1 isoform 1 bearing the R445H and D603H mutations. Some of these molecules were able to ameliorate the energetic functions and/or the mitochondrial network morphology, depending on the type of OPA1 mutation. The final validation has been performed in patients' fibroblasts, allowing to select the most effective molecules. Our current results are instrumental to rapidly translating the findings of this drug repurposing approach into clinical trial for DOA and other neurodegenerations caused by OPA1 mutations.


Subject(s)
Drug Repositioning , GTP Phosphohydrolases/genetics , Neurodegenerative Diseases/drug therapy , Optic Atrophy, Autosomal Dominant/drug therapy , Animals , DNA, Mitochondrial/drug effects , Fibroblasts/drug effects , GTP Phosphohydrolases/antagonists & inhibitors , Humans , Mice , Mitochondria/drug effects , Mitochondria/genetics , Mutation/drug effects , Neurodegenerative Diseases/genetics , Neurodegenerative Diseases/pathology , Optic Atrophy, Autosomal Dominant/genetics , Optic Atrophy, Autosomal Dominant/pathology , Pedigree , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/genetics
8.
Front Endocrinol (Lausanne) ; 11: 586242, 2020.
Article in English | MEDLINE | ID: mdl-33324344

ABSTRACT

Objective: To assess the effects of 17ß-estradiol (E2) on proliferation, apoptosis, and protein expressions of fibroblasts at different concentrations and time intervals to reveal the mechanism of E2 in the treatment of pelvic organ prolapse (POP). Study Design: The uterosacral ligament fibroblasts were collected from seven POP patients for primary culture of fibroblasts. The culture media containing 0, 10-6, 10-7, 10-8, and 10-9 mol/L E2 were used for 24, 48, 72, and 96 h. Main Outcome Measures: The cells were collected for cell counting kit-8 (CCK-8), apoptosis, quantitative reverse transcription polymerase chain reaction (qRT-PCR), and Western blotting assays. Results: Compared with the control group, in the values of fibroblasts cultured in 10-8 mol/L E2 for 72 h, the proliferation, mRNA and protein expression of Mitofusin-2 (Mfn2) separately increased (P < 0.05), decreased (P<0.001) and decreased (P<0.001). However, the expression level of procollagen 1A1/1A2/3A1 and cyclinD1 markedly increased (P<0.001, all), which was consistent with the results of protein level. What's more, the expression of estrogen receptor α(ERα), estrogen receptor ß(ERß) and G protein-coupled receptor 30(GPR30) were significantly increased in 10-8 mol/L E2 group. Conclusions: E2 can inhibit the progress of POP by inhibiting the expression level of Mfn2, as well as promoting expression of procollagens and proliferation of fibroblasts. This effect is time- and concentration-dependent. Only when the estrogen concentration reaches 10-8 mol/L, the therapeutic effect is the greatest after 72 h.


Subject(s)
Estradiol/pharmacology , GTP Phosphohydrolases/antagonists & inhibitors , Gene Expression Regulation/drug effects , Mitochondrial Proteins/antagonists & inhibitors , Pelvic Organ Prolapse/pathology , Aged , Apoptosis , Case-Control Studies , Cell Proliferation , Cells, Cultured , Estrogens/pharmacology , Female , Fibroblasts , GTP Phosphohydrolases/genetics , GTP Phosphohydrolases/metabolism , Humans , In Vitro Techniques , Middle Aged , Mitochondrial Proteins/genetics , Mitochondrial Proteins/metabolism , Pelvic Organ Prolapse/drug therapy , Pelvic Organ Prolapse/metabolism , Procollagen/metabolism
9.
Int J Mol Sci ; 21(21)2020 Oct 29.
Article in English | MEDLINE | ID: mdl-33138083

ABSTRACT

Phaeochromocytomas and paragangliomas (PPGLs) are neuroendocrine catecholamine-producing tumours that may progress into inoperable metastatic disease. Treatment options for metastatic disease are limited, indicating a need for functional studies to identify pharmacologically targetable pathophysiological mechanisms, which require biologically relevant experimental models. Recently, a human progenitor phaeochromocytoma cell line named "hPheo1" was established, but its genotype has not been characterised. Performing exome sequencing analysis, we identified a KIF1B T827I mutation, and the oncogenic NRAS Q61K mutation. While KIF1B mutations are recurring somatic events in PPGLs, NRAS mutations have hitherto not been detected in PPGLs. Therefore, we aimed to assess its implications for the hPheo1 cell line, and possible relevance for the pathophysiology of PPGLs. We found that transient downregulation of NRAS in hPheo1 led to elevated expression of genes associated with cell adhesion, and enhanced adhesion to hPheo1 cells' extracellular matrix. Analyses of previously published mRNA data from two independent PPGL patient cohorts (212 tissue samples) revealed a subcluster of PPGLs featuring hyperactivated RAS pathway-signalling and under-expression of cell adhesion-related gene expression programs. Thus, we conclude that NRAS activity in hPheo1 decreases adhesion to their own extracellular matrix and mirrors a transcriptomic RAS-signalling-related phenomenon in PPGLs.


Subject(s)
Adrenal Gland Neoplasms/pathology , Biomarkers, Tumor/metabolism , Cell Adhesion , GTP Phosphohydrolases/metabolism , Gene Expression Regulation, Neoplastic , Membrane Proteins/metabolism , Pheochromocytoma/pathology , RNA, Small Interfering/genetics , Adrenal Gland Neoplasms/genetics , Adrenal Gland Neoplasms/metabolism , Biomarkers, Tumor/genetics , GTP Phosphohydrolases/antagonists & inhibitors , GTP Phosphohydrolases/genetics , Gene Expression Profiling , Humans , Membrane Proteins/antagonists & inhibitors , Membrane Proteins/genetics , Pheochromocytoma/genetics , Pheochromocytoma/metabolism , Prognosis , Tumor Cells, Cultured
10.
ACS Chem Biol ; 15(8): 2079-2086, 2020 08 21.
Article in English | MEDLINE | ID: mdl-32568509

ABSTRACT

Activating mutations in the small GTPase NRAS are responsible for driving tumor growth in several cancers. Unfortunately, the development of NRAS inhibitors has proven difficult due to the lack of hydrophobic binding pockets on the protein's surface. To overcome this limitation, we chose to target the post-translational S-palmitoyl modification of NRAS, which is required for its signaling activity. Utilizing an amphiphile-mediated depalmitoylation (AMD) strategy, we demonstrate the ability to directly cleave S-palmitoyl groups from NRAS and inhibit its function. C8 alkyl cysteine causes a dose-dependent decrease in NRAS palmitoylation and inhibits downstream signaling in melanoma cells with an activating mutation in NRAS. This compound reduces cell growth in NRAS-driven versus non-NRAS-driven melanoma lines and inhibits tumor progression in an NRAS-mutated melanoma xenograft mouse model. Our work demonstrates that AMD can effectively suppress NRAS activity and could represent a promising new avenue for discovering lead compounds for treatment of NRAS-driven cancers.


Subject(s)
GTP Phosphohydrolases/antagonists & inhibitors , Lipoylation , Melanoma/metabolism , Membrane Proteins/antagonists & inhibitors , Signal Transduction , Skin Neoplasms/metabolism , Apoptosis/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , GTP Phosphohydrolases/metabolism , HeLa Cells , Humans , Melanoma/pathology , Membrane Proteins/metabolism , Protein Kinase Inhibitors/pharmacology , Skin Neoplasms/pathology
11.
Biochim Biophys Acta Rev Cancer ; 1873(2): 188364, 2020 04.
Article in English | MEDLINE | ID: mdl-32275934

ABSTRACT

Hyperactivation of the Mitogen Activated Protein Kinase (MAPK) pathway is prevalent in melanoma, principally due to mutations in the BRAF and NRAS genes. MAPK inhibitors are effective only short-term, and recurrence occurs due to functional redundancies or intertwined pathways. The remodeling of Ca2+ signaling is also common in melanoma cells, partly through the increased expression of T-type channels (TTCCs). Here we summarize current knowledge about the prognostic value and molecular targeting of TTCCs. Furthermore, we discuss recent evidence pointing to TTCCs as molecular switches for melanoma chemoresistance, which set the grounds for novel combined therapies against the advanced disease.


Subject(s)
Antineoplastic Agents/therapeutic use , Calcium Channels, T-Type/metabolism , MAP Kinase Signaling System/drug effects , Melanoma/drug therapy , Skin Neoplasms/drug therapy , Antineoplastic Agents/pharmacology , Calcium Channel Blockers/pharmacology , Calcium Channel Blockers/therapeutic use , Cell Line, Tumor , Disease Progression , Drug Resistance, Neoplasm/drug effects , Drug Resistance, Neoplasm/genetics , GTP Phosphohydrolases/antagonists & inhibitors , GTP Phosphohydrolases/genetics , Humans , Kaplan-Meier Estimate , MAP Kinase Signaling System/genetics , Melanoma/genetics , Melanoma/mortality , Melanoma/pathology , Membrane Proteins/antagonists & inhibitors , Membrane Proteins/genetics , Mutation , Prognosis , Protein Kinase Inhibitors/pharmacology , Protein Kinase Inhibitors/therapeutic use , Proto-Oncogene Proteins B-raf/antagonists & inhibitors , Proto-Oncogene Proteins B-raf/genetics , Skin Neoplasms/genetics , Skin Neoplasms/mortality , Skin Neoplasms/pathology , Treatment Outcome
12.
J Dairy Sci ; 103(6): 5561-5574, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32278565

ABSTRACT

Inflammation is critical in the progression from benign hepatic lipidosis to pathological hepatic steatosis. The objective of this study was to examine the potential role of the outer mitochondrial membrane protein mitofusin 2 (MFN2) in the etiology of hepatic steatosis in dairy cows during early lactation. Using a nested case-control design, we compared blood and liver samples from 10 healthy cows and 10 age-matched cows with moderate fatty liver. Cows with moderate fatty liver had high liver triacylglycerols, elevated plasma concentrations of free fatty acids (FFA) and ß-hydroxybutyrate, and low concentrations of glucose. Cows with moderate fatty liver had overactivated inflammatory pathways in the liver, as indicated by increased abundance of phosphorylated nuclear factor κB (NF-κB) p65, NLR family pyrin domain containing 3 (NLRP3) and caspase-1 inflammasome protein, and elevated plasma concentrations and hepatic mRNA abundance of their molecular targets IL-1ß, IL-6, and tumor necrosis factor α (TNF-α). In the cell culture model, we were able to replicate our findings in cows with moderate fatty liver: 1.2 mM exogenous FFA decreased the abundance of MFN2 and upregulated phosphorylation levels of the inhibitor of NF-κB (IκB) α and NF-κB p65, the IκB kinase ß activity, and the abundance of NLRP3, caspase-1, IL-1ß, IL-6, and TNF-α. Whereas MFN2 knockdown potentiated the FFA-induced activation of these inflammatory pathways, overexpression of MFN2 attenuated the detrimental effect of excess exogenous FFA by improving mitochondrial function and decreasing the release of reactive oxygen species, suggesting that MFN2 may be a potential therapeutic target for FFA-induced hepatic inflammation in dairy cows during early lactation.


Subject(s)
Cattle Diseases/prevention & control , Fatty Acids, Nonesterified/adverse effects , Fatty Liver/veterinary , GTP Phosphohydrolases/antagonists & inhibitors , Inflammation/veterinary , Mitochondrial Membranes/metabolism , Mitochondrial Proteins/antagonists & inhibitors , Animals , Case-Control Studies , Cattle , Fatty Acids, Nonesterified/blood , Fatty Liver/chemically induced , Fatty Liver/prevention & control , Female , GTP Phosphohydrolases/metabolism , Gene Expression Regulation, Enzymologic/drug effects , Inflammation/chemically induced , Inflammation/metabolism , Lactation/drug effects , Mitochondrial Proteins/metabolism , Reactive Oxygen Species/metabolism
13.
J Neurochem ; 155(2): 191-206, 2020 09.
Article in English | MEDLINE | ID: mdl-32157699

ABSTRACT

Mitochondrial dysfunction has a recognised role in the progression of Alzheimer's disease (AD) pathophysiology. Cerebral perfusion becomes increasingly inefficient throughout ageing, leading to unbalanced mitochondrial dynamics. This effect is exaggerated by amyloid ß (Aß) and phosphorylated tau, two hallmark proteins of AD pathology. A neuroprotective role for the adipose-derived hormone, leptin, has been demonstrated in neuronal cells. However, its effects with relation to mitochondrial function in AD remain largely unknown. To address this question, we have used both a glucose-serum-deprived (CGSD) model of ischaemic stroke in SH-SY5Y cells and a Aß1-42 -treatment model of AD in differentiated hippocampal cells. Using a combination of 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide (JC-1) and MitoRed staining techniques, we show that leptin prevents depolarisation of the mitochondrial membrane and excessive mitochondrial fragmentation induced by both CGSD and Aß1-42 . Thereafter, we used ELISAs and a number of activity assays to reveal the biochemical underpinnings of these processes. Specifically, leptin was seen to inhibit up-regulation of the mitochondrial fission protein Fis1 and down-regulation of the mitochondrial fusion protein, Mfn2. Furthermore, leptin was seen to up-regulate the expression and activity of the antioxidant enzyme, monoamine oxidase B. Herein we provide the first demonstration that leptin is sufficient to protect against aberrant mitochondrial dynamics and resulting loss of function induced by both CGSD and Aß1-42 . We conclude that the established neuroprotective actions of leptin may be facilitated through regulation of mitochondrial dynamics.


Subject(s)
Leptin/pharmacology , Mitochondria/metabolism , Mitochondria/ultrastructure , Mitochondrial Dynamics/drug effects , Neuroprotective Agents/pharmacology , Amyloid beta-Peptides/pharmacology , Animals , Cell Line , GTP Phosphohydrolases/antagonists & inhibitors , GTP Phosphohydrolases/biosynthesis , Glucose/deficiency , Hippocampus/cytology , Hippocampus/pathology , Humans , Ischemic Stroke/drug therapy , Mice , Mitochondria/drug effects , Mitochondrial Membranes/drug effects , Mitochondrial Proteins/antagonists & inhibitors , Mitochondrial Proteins/biosynthesis , Monoamine Oxidase/metabolism , Peptide Fragments/pharmacology , Reactive Oxygen Species/metabolism
14.
Eur J Med Chem ; 190: 112132, 2020 Mar 15.
Article in English | MEDLINE | ID: mdl-32066012

ABSTRACT

Cystic fibrosis is a rare genetic disease characterized by the production of dehydrated mucus in the lung able to trap bacteria and rendering their proliferation particularly dangerous, thus leading to chronic infections. Among these bacteria, Staphylococcus aureus and Pseudomonas aeruginosa play a major role while, within emerging pathogens, Stenotrophomonas maltophilia, Achromobacter xylosoxidans, Burkholderia cepacia complex species, as well as non-tuberculous mycobacteria are listed. Since a common feature of these bacteria is the high level of drug resistance, cell division, and in particular FtsZ, has been explored as a novel therapeutic target for the design of new molecules with antibacterial properties. This review summarizes and provides insight into recent advances in the discovery of compounds targeting FtsZ: the majority of them exhibit anti-staphylococcal activity, while a few were directed against the cystic fibrosis Gram negative pathogens.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacterial Proteins/antagonists & inhibitors , Cytoskeletal Proteins/antagonists & inhibitors , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/therapeutic use , Cystic Fibrosis/microbiology , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , GTP Phosphohydrolases/antagonists & inhibitors , Gram-Negative Bacteria/drug effects , Humans , Staphylococcal Infections/drug therapy , Staphylococcus aureus/drug effects
16.
J Biol Chem ; 295(9): 2866-2884, 2020 02 28.
Article in English | MEDLINE | ID: mdl-31959628

ABSTRACT

Aberrant Ras signaling drives 30% of cancers, and inhibition of the Rho family small GTPase signaling has been shown to combat Ras-driven cancers. Here, we present the discovery of a 16-mer cyclic peptide that binds to Cdc42 with nanomolar affinity. Affinity maturation of this sequence has produced a panel of derived candidates with increased affinity and modulated specificity for other closely-related small GTPases. The structure of the tightest binding peptide was solved by NMR, and its binding site on Cdc42 was determined. Addition of a cell-penetrating sequence allowed the peptides to access the cell interior and engage with their target(s), modulating signaling pathways. In Ras-driven cancer cell models, the peptides have an inhibitory effect on proliferation and show suppression of both invasion and motility. As such, they represent promising candidates for Rho-family small GTPase inhibitors and therapeutics targeting Ras-driven cancers. Our data add to the growing literature demonstrating that peptides are establishing their place in the biologics arm of drug discovery.


Subject(s)
Drug Discovery , Peptides, Cyclic/pharmacology , Signal Transduction/drug effects , cdc42 GTP-Binding Protein/antagonists & inhibitors , ras Proteins/metabolism , Binding Sites , Cell Movement/drug effects , Cell Proliferation/drug effects , Cell-Penetrating Peptides , GTP Phosphohydrolases/antagonists & inhibitors , Humans , Molecular Structure , Neoplasm Invasiveness/prevention & control , Neoplasms/drug therapy , Peptides, Cyclic/chemistry , Peptides, Cyclic/metabolism , cdc42 GTP-Binding Protein/metabolism
17.
J Biol Chem ; 295(51): 17684-17697, 2020 12 18.
Article in English | MEDLINE | ID: mdl-33454007

ABSTRACT

Tuberculosis (TB), caused by the infection of Mycobacterium tuberculosis (MTB), is one of the leading causes of death worldwide, especially in children. However, the mechanisms by which MTB infects its cellular host, activates an immune response, and triggers inflammation remain unknown. Mitochondria play important roles in the initiation and activation of the nucleotide-binding oligomerization domain-like receptor with a pyrin domain 3 (NLRP3) inflammasome, where mitochondria-associated endoplasmic reticulum membranes (MAMs) may serve as the platform for inflammasome assembly and activation. Additionally, mitofusin 2 (MFN2) is implicated in the formation of MAMs, but, the roles of mitochondria and MFN2 in MTB infection have not been elucidated. Using mircroarry profiling of TB patients and in vitro MTB stimulation of macrophages, we observed an up-regulation of MFN2 in the peripheral blood mononuclear cells of active TB patients. Furthermore, we found that MTB stimulation by MTB-specific antigen ESAT-6 or lysate of MTB promoted MFN2 interaction with NLRP3 inflammasomes, resulting in the assembly and activation of the inflammasome and, subsequently, IL-1ß secretion. These findings suggest that MFN2 and mitochondria play important role in the pathogen-host interaction during MTB infection.


Subject(s)
GTP Phosphohydrolases/metabolism , Inflammasomes/metabolism , Mitochondrial Proteins/metabolism , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Tuberculosis/pathology , Antigens, Bacterial/chemistry , Antigens, Bacterial/metabolism , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Case-Control Studies , GTP Phosphohydrolases/antagonists & inhibitors , GTP Phosphohydrolases/genetics , Host-Pathogen Interactions , Humans , Interleukin-1beta/metabolism , Leukocytes, Mononuclear/metabolism , Macrophages/cytology , Macrophages/metabolism , Macrophages/microbiology , Membrane Potential, Mitochondrial , Mitochondria/metabolism , Mitochondrial Proteins/antagonists & inhibitors , Mitochondrial Proteins/genetics , Mycobacterium tuberculosis/physiology , NLR Family, Pyrin Domain-Containing 3 Protein/chemistry , Protein Binding , RNA Interference , RNA, Small Interfering/metabolism , Tuberculosis/metabolism , Up-Regulation
18.
Curr Opin Oncol ; 32(2): 79-84, 2020 03.
Article in English | MEDLINE | ID: mdl-31833955

ABSTRACT

PURPOSE OF REVIEW: Melanoma treatment have been revolutionized since 2010 by the development of immune checkpoint inhibitors, and, for BRAF-mutated melanoma, targeted therapies based on BRAF and MEK inhibitors, which is a model of effective targeted therapy in cancer. However, patients with BRAF wild type cannot benefit for such treatments. In this review, we will focus on the current clinical development of targeted therapies beyond BRAF, in NRAS-mutated and KIT-altered melanoma. RECENT FINDINGS: In NRAS-mutated melanoma, targeted therapies based on MEK inhibition are being developed as monotherapy or in combination with MAPK, PI3K or CDK4/6 inhibitor. Targeted therapies of KIT-altered melanoma patients is based in KIT inhibitor (mostly imatinib, nilotinib), although for both melanoma subtypes, results are for now disappointing as compared with BRAF and MEK inhibitors in BRAF-mutated melanoma. SUMMARY: Combined therapeutic targeted strategies are awaited in NRAS-mutated and KIT-altered melanoma and could provide additional benefit.


Subject(s)
GTP Phosphohydrolases/antagonists & inhibitors , Melanoma/drug therapy , Membrane Proteins/antagonists & inhibitors , Proto-Oncogene Proteins B-raf/antagonists & inhibitors , Proto-Oncogene Proteins c-kit/antagonists & inhibitors , Clinical Trials, Phase III as Topic , GTP Phosphohydrolases/genetics , Humans , Melanoma/enzymology , Melanoma/genetics , Membrane Proteins/genetics , Molecular Targeted Therapy , Mutation , Protein Kinase Inhibitors/therapeutic use , Proto-Oncogene Proteins B-raf/genetics , Proto-Oncogene Proteins c-kit/genetics , Randomized Controlled Trials as Topic , Skin Neoplasms/drug therapy , Skin Neoplasms/enzymology , Skin Neoplasms/genetics
19.
Kidney Blood Press Res ; 44(4): 513-532, 2019.
Article in English | MEDLINE | ID: mdl-31266025

ABSTRACT

Elevated homocysteine (Hcy) levels have been shown to activate nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome leading to podocyte dysfunction and glomerular injury. However, it remains unclear how this inflammasome activation in podocytes is a therapeutic target for reversal of glomerular injury and ultimate sclerosis. The present study tested whether inhibition of Rac1 GTPase activity suppresses NLRP3 inflammation activation and thereby blocks podocyte injury induced by elevated Hcy. In cultured podocytes, we found that L-Hcy (the active Hcy form) stimulated the NLRP3 inflammasome formation, as shown by increased colocalization of NLRP3 with apoptosis-associated speck-like protein (ASC) or caspase-1, which was accompanied by increased interleukin-1ß production and caspase-1 activity, indicating NLRP3 inflammasome activation. Rac1 activator, uridine triphosphate (UTP), mimicked L-Hcy-induced NLRP3 inflammasome activation, while Rac1 inhibitor NSC23766 blocked it. This Rac1 inhibition also prevented L-Hcy-induced podocyte dysfunction. All these effects were shown to be mediated via lipid raft redox signaling platforms with nicotinamide adenine dinucleotide phosphate oxidase subunits and consequent O2- production. In animal studies, hyperhomocysteinemia (hHcy) induced by folate-free diet was shown to induce NLRP3 inflammasome formation and activation in glomeruli, which was also mimicked by UTP and inhibited by NSC23766 to a comparable level seen in Nlrp3 gene knockout mice. These results together suggest that Rac1 inhibition protects the kidney from hHcy-induced podocyte injury and glomerular sclerosis due to its action to suppress NLRP3 inflammasome activation in podocytes.


Subject(s)
GTP Phosphohydrolases/antagonists & inhibitors , Hyperhomocysteinemia/metabolism , Inflammasomes/metabolism , Kidney Glomerulus/pathology , Podocytes/pathology , Animals , Cells, Cultured , Enzyme Inhibitors/pharmacology , Humans , Hyperhomocysteinemia/complications , Inflammasomes/chemistry , Inflammasomes/drug effects , Mice , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Podocytes/drug effects , Protective Agents , Sclerosis/prevention & control , rac1 GTP-Binding Protein/antagonists & inhibitors
20.
Bioorg Chem ; 90: 103031, 2019 09.
Article in English | MEDLINE | ID: mdl-31238181

ABSTRACT

Curcumin is a plant diphenylheptanoid and has been investigated for its antibacterial activity. However, the therapeutic uses of this compound are limited due to its chemical instability. In this work, we evaluated the antimicrobial activity of diphenylheptanoids derived from curcumin against Gram-positive and Gram-negative bacteria, and also against Mycobacterium tuberculosis in terms of MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) values. 3,3'-Dihydroxycurcumin (DHC) displayed activity against Enterococcus faecalis, Staphylococcus aureus and M. tuberculosis, demonstrating MIC values of 78 and 156 µg/mL. In addition, DHC was more stable than curcumin in acetate buffer (pH 5.0) and phosphate buffer (pH 7.4) for 24 h at 37 °C. We proposed that membrane and the cell division protein FtsZ could be the targets for DHC due to that fact that curcumin exhibits this mode of antibacterial action. Fluorescence microscopy of Bacillus subtilis stained with SYTO9 and propidium iodide fluorophores indicated that DHC has the ability to perturb the bacterial membrane. On the other hand, DHC showed a weak inhibition of the GTPase activity of B. subtilis FtsZ. Toxicity assay using human cells indicated that DHC has moderate capacity to reduce viability of liver cells (HepG2 line) and lung cells (MRC-5 and A549 lines) when compared with doxorubicin. Alkaline comet assay indicated that DHC was not able to induce DNA damage in A549 cell line. These results indicated that DHC is promising compound with antibacterial and antitubercular activities.


Subject(s)
Antitubercular Agents/pharmacology , Cell Membrane/drug effects , Curcumin/analogs & derivatives , Curcumin/pharmacology , Antitubercular Agents/chemical synthesis , Antitubercular Agents/toxicity , Bacteria/drug effects , Bacterial Proteins/antagonists & inhibitors , Cell Line, Tumor , Curcumin/toxicity , Cytoskeletal Proteins/antagonists & inhibitors , DNA/drug effects , Drug Stability , GTP Phosphohydrolases/antagonists & inhibitors , Humans , Microbial Sensitivity Tests
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