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1.
Biol. Res ; 52: 26, 2019. graf
Article in English | LILACS | ID: biblio-1011428

ABSTRACT

BACKGROUND: Acute myeloid leukemia (AML) is an aggressive and mostly incurable hematological malignancy with frequent relapses after an initial response to standard chemotherapy. Therefore, novel therapies are urgently required to improve AML clinical outcomes. 4-Amino-2-trifluoromethyl-phenyl retinate (ATPR), a novel all-trans retinoic acid (ATRA) derivative designed and synthesized by our team, has been proven to show biological anti-tumor characteristics in our previous studies. However, its potential effect on leukemia remains unknown. The present research aims to investigate the underlying mechanism of treating leukemia with ATPR in vitro. METHODS: In this study, the AML cell lines NB4 and THP-1 were treated with ATPR. Cell proliferation was analyzed by the CCK-8 assay. Flow cytometry was used to measure the cell cycle distribution and cell differentiation. The expression levels of cell cycle and differentiation-related proteins were detected by western blotting and immunofluorescence staining. The NBT reduction assay was used to detect cell differentiation. RESULTS: ATPR inhibited cell proliferation, induced cell differentiation and arrested the cell cycle at the G0/G1 phase. Moreover, ATPR treatment induced a time-dependent release of reactive oxygen species (ROS). Additionally, the PTEN/PI3K/Akt pathway was downregulated 24 h after ATPR treatment, which might account for the anti-AML effects of ATPR that result from the ROS-mediated regulation of the PTEN/PI3K/AKT signaling pathway. CONCLUSIONS: Our observations could help to develop new drugs targeting the ROS/PTEN/PI3K/Akt pathway for the treatment of AML.


Subject(s)
Humans , Retinoids/pharmacology , Reactive Oxygen Species/metabolism , Antineoplastic Agents/pharmacology , Fluoroimmunoassay , Leukemia, Myeloid, Acute , Signal Transduction , Down-Regulation , Cell Differentiation/drug effects , Cell Survival/drug effects , Phosphatidylinositol 3-Kinases/metabolism , Cell Line, Tumor , Cell Proliferation/drug effects , PTEN Phosphohydrolase/drug effects , PTEN Phosphohydrolase/metabolism , Proto-Oncogene Proteins c-akt/drug effects , Proto-Oncogene Proteins c-akt/metabolism
2.
Biol. Res ; 52: 7, 2019. graf
Article in English | LILACS | ID: biblio-1011410

ABSTRACT

BACKGROUND: Currently, the prognosis of patients with non-small cell lung cancer (NSCLC) remains dismal; hence, it is critical to identify effective anti-NSCLC agents with limited side effects. This study aimed to evaluate the therapeutic potential of flavonoid compound vitexin in human NSCLC cells and the underlying mechanisms. RESULTS: The experimental results indicated that vitexin reduced the viability of A549 cells in a dose-dependent manner with nearly no toxicity against normal human bronchial epithelial 16HBE cells. Vitexin also dose-dependently increased A549 cell apoptosis, accompanied by the decreased Bcl-2/Bax ratio and the increased expression of cleaved caspase-3. Moreover, the in vivo anticancer activity of vitexin was further determined in nude mice bearing A549 cells. In addition, vitexin induced the release of cytochrome c from the mitochondria to the cytosol and the loss of mitochondrial membrane potential. Vitexin also significantly reduced the levels of p-PI3K, p-Akt and p-mTOR, and the pro-apoptotic effect of vitexin on A549 cells was partly blocked by SC79, an Akt activator. CONCLUSIONS: Accordingly, we believed that vitexin could be used as a potential therapeutic agent for the treatment of NSCLC in the future.


Subject(s)
Humans , Animals , Mice , Apoptosis/drug effects , Carcinoma, Non-Small-Cell Lung/pathology , Phosphatidylinositol 3-Kinases/drug effects , Apigenin/pharmacology , Proto-Oncogene Proteins c-akt/drug effects , TOR Serine-Threonine Kinases/drug effects , Lung Neoplasms/pathology , Antineoplastic Agents/pharmacology , Signal Transduction/drug effects , Carcinoma, Non-Small-Cell Lung/metabolism , Cell Line, Tumor , Cell Proliferation/drug effects , Membrane Potential, Mitochondrial/drug effects , A549 Cells , Lung Neoplasms/metabolism , Mice, Nude , Mitochondria/drug effects
3.
Biol. Res ; 51: 17, 2018. graf
Article in English | LILACS | ID: biblio-950903

ABSTRACT

BACKGROUND: Improper control on reactive oxygen species (ROS) elimination process and formation of free radicals causes tissue dysfunction. Pineal hormone melatonin is considered a potent regulator of such oxidative damage in different vertebrates. Aim of the current communication is to evaluate the levels of oxidative stress and ROS induced damage, and amelioration of oxidative status through melatonin induced activation of signaling pathways. Hepatocytes were isolated from adult Labeo rohita and exposed to H2O2 at three different doses (12.5, 25 and 50 µM) to observe peroxide induced damage in fish hepatocytes. Melatonin (25, 50 and 100 µg/ml) was administered against the highest dose of H2O2. Enzymatic and non-enzymatic antioxidants such as malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) was measured spectrophotometrically. Expression level of heat shock proteins (HSP70 and HSP90), HSPs-associated signaling molecules (Akt, ERK, cytosolic and nuclear NFkB), and melatonin receptor was also measured by western blotting analysis. RESULTS: H2O2 induced oxidative stress significantly altered (P < 0.05) MDA and GSH level, SOD and CAT activity, and up regulated HSP70 and HSP90 expression in carp hepatocytes. Signaling proteins exhibited differential modulation as revealed from their expression patterns in H2O2-exposed fish hepatocytes, in comparison with control hepatocytes. Melatonin treatment of H2O2-stressed fish hepatocytes restored basal cellular oxidative status in a dose dependent manner. Melatonin was observed to be inducer of signaling process by modulation of signaling molecules and melatonin receptor. CONCLUSIONS: The results suggest that exogenous melatonin at the concentration of 100 µg/ml is required to improve oxidative status of the H2O2-stressed fish hepatocytes. In H2O2 exposed hepatocytes, melatonin modulates expression of HSP70 and HSP90 that enable the hepatocytes to become stress tolerant and survive by altering the actions of ERK, Akt, cytosolic and nuclear NFkB in the signal transduction pathways. Study also confirms that melatonin could act through melatonin receptor coupled to ERK/Akt signaling pathways. This understanding of the mechanism by which melatonin regulates oxidative status in the stressed hepatocytes may initiate the development of novel strategies for hepatic disease therapy in future.


Subject(s)
Animals , Signal Transduction/drug effects , Oxidative Stress/drug effects , Hepatocytes/drug effects , Hydrogen Peroxide/pharmacology , Melatonin/pharmacology , Spectrophotometry , Superoxide Dismutase/drug effects , Catalase/drug effects , Catalase/metabolism , Blotting, Western , NF-kappa B/drug effects , NF-kappa B/metabolism , Reactive Oxygen Species/metabolism , MAP Kinase Signaling System/drug effects , Hepatocytes/metabolism , Proto-Oncogene Proteins c-akt/drug effects , Fishes , Glutathione/drug effects , Glutathione/metabolism , Malondialdehyde/metabolism
4.
Braz. j. med. biol. res ; 51(1): e6472, 2018. graf
Article in English | LILACS | ID: biblio-889011

ABSTRACT

Cetuximab is widely used in patients with metastatic colon cancer expressing wildtype KRAS. However, acquired drug resistance limits its clinical efficacy. Exosomes are nanosized vesicles secreted by various cell types. Tumor cell-derived exosomes participate in many biological processes, including tumor invasion, metastasis, and drug resistance. In this study, exosomes derived from cetuximab-resistant RKO colon cancer cells induced cetuximab resistance in cetuximab-sensitive Caco-2 cells. Meanwhile, exosomes from RKO and Caco-2 cells showed different levels of phosphatase and tensin homolog (PTEN) and phosphor-Akt. Furthermore, reduced PTEN and increased phosphorylated Akt levels were found in Caco-2 cells after exposure to RKO cell-derived exosomes. Moreover, an Akt inhibitor prevented RKO cell-derived exosome-induced drug resistance in Caco-2 cells. These findings provide novel evidence that exosomes derived from cetuximab-resistant cells could induce cetuximab resistance in cetuximab-sensitive cells, by downregulating PTEN and increasing phosphorylated Akt levels.


Subject(s)
Humans , Colonic Neoplasms/drug therapy , PTEN Phosphohydrolase/drug effects , Proto-Oncogene Proteins c-akt/drug effects , Exosomes/drug effects , Cetuximab/pharmacology , Antineoplastic Agents, Immunological/pharmacology , Tetrazolium Salts , Time Factors , Blotting, Western , Analysis of Variance , Caco-2 Cells , Cell Line, Tumor
5.
Braz. j. med. biol. res ; 51(5): e6889, 2018. graf
Article in English | LILACS | ID: biblio-889078

ABSTRACT

2-Methyl-2-butanol (MBT) is a chemical compound from the group of alcohols more specifically pentanols, which has shown an excellent anti-cancer activity in our previous study. However, its mechanism of action remains unclear. The present study was designed to investigate the anti-cancer effect of MBT on human retinoblastoma cells. The results showed that the use of MBT leads to HXO-RB44 cell death but is cytotoxic to normal cells at higher concentrations. It showed a dose- as well as a time-dependent inhibition of HXO-RB44 cells. P27 is a cell cycle inhibitory protein, which plays an important role in cell cycle regulation whereas cyclin-B1 is a regulatory protein involved in mitosis. MBT increased the cell cycle arrest in a dose-dependent manner by augmenting p27 and reducing cyclin B1 expression. Moreover, it also accelerated apoptosis, increased light chain-3 (LC-3) conversion in a dose-dependent manner, and helped to debulk cancerous cells. LC3 is a soluble protein, which helps to engulf cytoplasmic components, including cytosolic proteins and organelles during autophagy from autophagosomes. In order to verify the effect of MBT, bafilomycin A1, an autophagy inhibitor, was used to block the MTB-induced apoptosis and necrosis. Additionally, a specific Akt agonist, SC-79, reversed the MBT-induced cell cycle arrest and autophagy. Thus, from the present study, it was concluded that MBT induced cell cycle arrest, apoptosis and autophagy through the PI3K/Akt pathway in HXO-RB44 cells.


Subject(s)
Humans , Antineoplastic Agents/pharmacology , Autophagy/drug effects , Cell Cycle Checkpoints/drug effects , Pentanols/pharmacology , Retinoblastoma/pathology , Blotting, Western , Phosphatidylinositol 3-Kinases/drug effects , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/drug effects , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction , Tumor Cells, Cultured
6.
Acta cir. bras ; 32(10): 862-872, Oct. 2017. graf
Article in English | LILACS | ID: biblio-886174

ABSTRACT

Abstract Purpose: To investigate whether the neuroprotective effect of TSA on cerebral ischemia reperfusion injury is mediated by the activation of Akt/GSK-3β signaling pathway. Methods: Mice were randomly divided into four groups (n=15): sham group (S); ischemia reperfusion group (IR); ischemia reperfusion and pretreated with TSA group (IR+T); ischemia reperfusion and pretreated with TSA and LY294002 group (IR+T+L). The model of cerebral ischemia reperfusion was established by 1h of MCAO following 24h of reperfusion. TSA (5mg/kg) was intraperitoneally given for 3 days before MCAO, Akt inhibitor, LY294002 (15 nmol/kg) was injected by tail vein 30 min before the MCAO. Results: TSA significantly increased the expression of p-Akt, p-GSK-3β proteins and the levels of SOD, Bcl-2, reduced the infarct volume and the levels of MDA, ROS, TNF-α, IL-1β, Bax, Caspase-3, TUNEL and attenuated neurological deficit in mice with transient MCAO, LY294002 weakened such effect of TSA dramatically. Conclusions: TSA could significantly decrease the neurological deficit and reduce the cerebral infarct volume, oxidative stress, inflammation, as well as apoptosis during cerebral ischemia reperfusion injury, which was achieved by activation of the Akt/GSK-3β signaling pathway.


Subject(s)
Animals , Male , Rats , Signal Transduction/drug effects , Ischemic Attack, Transient/metabolism , Neuroprotective Agents/pharmacology , Glycogen Synthase Kinase 3/drug effects , Proto-Oncogene Proteins c-akt/drug effects , Histone Deacetylase Inhibitors/pharmacology , Signal Transduction/physiology , Ischemic Attack, Transient/physiopathology , Glycogen Synthase Kinase 3/metabolism , Disease Models, Animal , Mice, Inbred BALB C
7.
Braz. j. med. biol. res ; 50(8): e5991, 2017. graf
Article in English | LILACS | ID: biblio-888980

ABSTRACT

Asthma is a chronic allergic disease characterized by airway inflammation, airway hyper-responsiveness (AHR), and mucus hypersecretion. T-lymphocytes are involved in the pathogenesis of asthma, mediating airway inflammatory reactions by secreting cytokines. The phosphoinositide 3-kinase (PI3K) and Notch signaling pathways are associated with T cell signaling, proliferation, and differentiation, and are important in the progression of asthma. Thus, compounds that can modulate T cell proliferation and function may be of clinical value. Here, we assessed the effects of tangeretin, a plant-derived flavonoid, in experimental asthma. BALB/c mice at postnatal day (P) 12 were challenged with ovalbumin (OVA). Separate groups of mice (n=18/group) were administered tangeretin at 25 or 50 mg/kg body weight by oral gavage. Dexamethasone was used as a positive control. Tangeretin treatment reduced inflammatory cell infiltration in bronchoalveolar lavage fluid (BALF) and also restored the normal histology of lung tissues. OVA-specific IgE levels in serum and BALF were reduced. AHR, as determined by airway resistance and lung compliance, was normalized. Flow cytometry analyses revealed a reduced Th17 cell population. Tangeretin reduced the levels of Th2 and Th17 cytokines and raised IFN-γ levels. PI3K signaling was inhibited. The expressions of the Notch 1 receptor and its ligands Jagged 1 and 2 were downregulated by tangeretin. Our findings support the possible use of tangeretin for treating allergic asthma.


Subject(s)
Animals , Mice , Asthma/drug therapy , Signal Transduction/drug effects , Anti-Asthmatic Agents/therapeutic use , Flavones/therapeutic use , Asthma/immunology , Cytokines/drug effects , Cytokines/immunology , Th2 Cells/drug effects , Th2 Cells/immunology , Th1 Cells/drug effects , Th1 Cells/immunology , Disease Models, Animal , Proto-Oncogene Proteins c-akt/drug effects , Proto-Oncogene Proteins c-akt/immunology , Th17 Cells/drug effects , Th17 Cells/immunology , Animals, Newborn , Mice, Inbred BALB C
8.
Braz. j. med. biol. res ; 47(9): 773-779, 09/2014. graf
Article in English | LILACS | ID: lil-719311

ABSTRACT

The present study focuses on the neuroprotective effect of glycyrrhizic acid (GA, a major compound separated from Glycyrrhiza Radix, which is a crude Chinese traditional drug) against glutamate-induced cytotoxicity in differentiated PC12 (DPC12) cells. The results showed that GA treatment improved cell viability and ameliorated abnormal glutamate-induced alterations in mitochondria in DPC12 cells. GA reversed glutamate-suppressed B-cell lymphoma 2 levels, inhibited glutamate-enhanced expressions of Bax and cleaved caspase 3, and reduced cytochrome C (Cyto C) release. Exposure to glutamate strongly inhibited phosphorylation of AKT (protein kinase B) and extracellular signal-regulated kinases (ERKs); however, GA pretreatment enhanced activation of ERKs but not AKT. The presence of PD98059 (a mitogen-activated protein/extracellular signal-regulated kinase kinase [MEK] inhibitor) but not LY294002 (a phosphoinositide 3-kinase [PI3K] inhibitor) diminished the potency of GA for improving viability of glutamate-exposed DPC12 cells. These results indicated that ERKs and mitochondria-related pathways are essential for the neuroprotective effect of GA against glutamate-induced toxicity in DPC12 cells. The present study provides experimental evidence supporting GA as a potential therapeutic agent for use in the treatment of neurodegenerative diseases.


Subject(s)
Animals , Rats , Anti-Inflammatory Agents/therapeutic use , Glutamic Acid/toxicity , Glycyrrhizic Acid/therapeutic use , Neuroprotective Agents/therapeutic use , /drug effects , Signal Transduction/drug effects , Apoptosis/drug effects , /isolation & purification , Cell Differentiation/drug effects , Cell Survival/drug effects , Chromones/pharmacology , Cytochromes c/drug effects , Enzyme Inhibitors/pharmacology , Flavonoids/pharmacology , MAP Kinase Signaling System/drug effects , Mitochondria/drug effects , Morpholines/pharmacology , /classification , /cytology , Proto-Oncogene Proteins c-akt/drug effects , /isolation & purification , /isolation & purification
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