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1.
Int J Exp Pathol ; 2024 May 09.
Article En | MEDLINE | ID: mdl-38722178

Morphometry of striated muscle fibres is critical for monitoring muscle health and function. Here, we evaluated functional parameters of skeletal and cardiac striated muscle in two experimental models using the Morphometric Analysis of Muscle Fibre tool (MusMA). The collagen-induced arthritis model was used to evaluate the function of skeletal striated muscle and the non-alcoholic fatty liver disease model was used for cardiac striated muscle analysis. After euthanasia, we used haeamatoxylin and eosin stained sections of skeletal and cardiac muscle to perform muscle fibre segmentation and morphometric analysis. Morphometric analysis classified muscle fibres into six subpopulations: normal, regular hypertrophic, irregular hypertrophic, irregular, irregular atrophic and regular atrophic. The percentage of atrophic fibres was associated with lower walking speed (p = 0.009) and lower body weight (p = 0.026), respectively. Fibres categorized as normal were associated with maximum grip strength (p < 0.001) and higher march speed (p < 0.001). In the evaluation of cardiac striated muscle fibres, the percentage of normal cardiomyocytes negatively correlated with cardiovascular risk markers such as the presence of abdominal adipose tissue (p = .003), miR-33a expression (p = .001) and the expression of miR-126 (p = .042) Furthermore, the percentage of atrophic cardiomyocytes correlated significantly with the Castelli risk index II (p = .014). MusMA is a simple and objective tool that allows the screening of striated muscle fibre morphometry, which can complement the diagnosis of muscle diseases while providing functional and prognostic information in basic and clinical research.

2.
J Mol Med (Berl) ; 102(1): 39-52, 2024 Jan.
Article En | MEDLINE | ID: mdl-37878028

Less than 15% of patients with esophageal squamous cell carcinoma (ESCC) survive 5 years after diagnosis. A better understanding of the biology of these tumors and the development of clinical biomarkers is needed. Autophagy is a physiological mechanism involved in the turnover of cellular components that plays a key role in cancer. This study evaluated the differential levels of three key regulators of autophagy (SQSTM1, MAP1LC3B, and BECN1) in patients with ESCC, associating autophagy with histopathologic features, including the grade of differentiation, mitotic rate, inflammation score, and the intensity of tumor-infiltrating lymphocytes. Nuclear morphometry of the tumor parenchyma was also assessed, associating it with autophagy and histopathology. All three markers significantly increased in patients with ESCC compared to the control group. Based on the mean expression of each protein in the control group, 57% of patients with ESCC had high levels of all three markers compared to control patients (14%). The most frequent profiles found in ESCC were BECNhigh/MAP1LC3high and BECNhigh/SQSTM1high. According to the TCGA database, we found that the main autophagy genes were upregulated in ESCC. Moreover, high levels of autophagy markers were associated with a poor prognosis. Considering nuclear morphometry, ESCC samples showed a significant reduction in nuclear area, which was strongly negatively correlated with autophagy. Finally, the percentage of normal nuclei was associated with tumor differentiation, while poorly differentiated tumors showed lower SQSTM1 levels. ESCC progression may involve increased autophagy and changes in nuclear structure, associated with clinically relevant histopathological features. KEY MESSAGES: Autophagy markers are co-increased in primary ESCC. Autophagy negatively correlates with nuclear morphometry in ESCC parenchyma. Autophagy and nuclear morphometry are associated with histopathological features. Autophagy is increased in ESCC-TCGA database and associated with poor prognosis.


Carcinoma, Squamous Cell , Esophageal Neoplasms , Esophageal Squamous Cell Carcinoma , Humans , Esophageal Squamous Cell Carcinoma/pathology , Esophageal Neoplasms/metabolism , Carcinoma, Squamous Cell/pathology , Sequestosome-1 Protein/genetics , Sequestosome-1 Protein/metabolism , Biomarkers, Tumor/genetics , Autophagy
3.
Exp Cell Res ; 433(2): 113825, 2023 12 15.
Article En | MEDLINE | ID: mdl-37866459

Metabolic adaptations are central for carcinogenesis and response to therapy, but little is known about the contribution of mitochondrial dynamics to the response of glioma cells to the standard treatment with temozolomide (TMZ). Glioma cells responded to TMZ with mitochondrial mass increased and the production of round structures of dysfunctional mitochondria. At single-cell level, asymmetric mitosis contributed to the heterogeneity of mitochondrial levels. It affected the fitness of cells in control and treated condition, indicating that the mitochondrial levels are relevant for glioma cell fitness in the presence of TMZ.


Brain Neoplasms , Glioma , Humans , Temozolomide/pharmacology , Temozolomide/therapeutic use , Dacarbazine/pharmacology , Dacarbazine/metabolism , Dacarbazine/therapeutic use , Apoptosis , Cell Line, Tumor , Glioma/drug therapy , Glioma/metabolism , Mitochondria/metabolism , Antineoplastic Agents, Alkylating/pharmacology , Brain Neoplasms/drug therapy , Brain Neoplasms/metabolism , Drug Resistance, Neoplasm
4.
Anticancer Res ; 43(4): 1427-1436, 2023 Apr.
Article En | MEDLINE | ID: mdl-36974821

BACKGROUND/AIM: Central nervous system cancer is still a major public health issue. The effectiveness of treatments is limited and varies depending on the severity of disease. Therefore, there is a demand for the development of novel therapies. Static magnetic stimulation (SMS) emerges as a new therapeutic option. The aim of this study was to evaluate the SMS effects on neuroblastoma cells in culture. MATERIALS AND METHODS: SH-SY5Y neuroblastoma cells were exposed to 0.3T SMS for 6, 12, 24, 36, 72 h, and 6 days. Cell viability (MTT), cell death (annexin-V/PI staining) and cell cycle (DNA content), cell proliferation (CFSE), autophagy (acridine orange), and total mitochondrial mass (MitoTracker™ Red) were analyzed to establish the cellular response to SMS. RESULTS: The viability of SH-SY5Y cells was reduced after exposure to SMS for 24 h and 6 days (p<0.05), without differences for the other times (p>0.05); however, this effect was not related to cell death or cell cycle arrest (p>0.05). In contrast, the viability of human malignant melanoma (HMV-II) cells, used as a tumoral control, was not affected. In addition, stimulated SH-SY5Y cells presented a decrease in mitochondrial mass at both exposure times and a reduction in autophagy and cell proliferation after 6 days (p<0.05). CONCLUSION: SMS application appears to be a promising adjuvant therapy for the treatment of neuroblastoma since it decreases the survival of SH-SY5Y neuroblastoma cells.


Neuroblastoma , Humans , Neuroblastoma/drug therapy , Cell Line, Tumor , Cell Death , Cell Cycle Checkpoints , Magnetic Phenomena , Cell Survival , Apoptosis
5.
Arch Pathol Lab Med ; 147(6): 701-709, 2023 06 01.
Article En | MEDLINE | ID: mdl-36161791

CONTEXT.­: Nucleophosmin 1 (NPM1) mutations affect 20% to 30% of all acute myeloid leukemia (AML) patients; several methods are employed to analyze NPM1 mutations, each of them with its advantages and limitations. OBJECTIVE.­: To compare 3 nonsequencing protocols capable of detecting the main NPM1 mutations and to evaluate nuclear morphometric analysis (NMA) as an alternative to cuplike blast detection. DESIGN.­: We selected multiparameter flow cytometry (MFC), amplification refractory mutation system-polymerase chain reaction (ARMS-PCR), and a quantitative PCR (qPCR) kit to identify NPM1 mutations in AML patients at diagnosis. We also evaluated the presence of cuplike blasts and assessed nuclear morphometry using NMA. RESULTS.­: MFC appears as a screening method for NPM1 mutations because of its lower specificity. ARMS-PCR demonstrated specificity similar to that of the qPCR kit, although it was more laborious. qPCR testing, conversely, is relatively fast and easy to standardize. Of these methods, qPCR was the only one capable of identifying the type of NPM1 mutation. With regard to morphology, NMA could be used as an alternative for the evaluation of cuplike blasts in AML smears. CONCLUSIONS.­: qPCR appears to be the best option to identify NPM1 mutations, with ARMS-PCR representing a cheaper alternative. MFC may be used as a screening method, in which results falling within and above the gray zone should be confirmed by molecular testing.


Leukemia, Myeloid, Acute , Nuclear Proteins , Humans , Nuclear Proteins/genetics , Nucleophosmin , Mutation , Cell Nucleus , Leukemia, Myeloid, Acute/diagnosis , Leukemia, Myeloid, Acute/genetics
6.
Toxicol In Vitro ; 85: 105472, 2022 Dec.
Article En | MEDLINE | ID: mdl-36116745

Vincristine (VCR) is a classical chemotherapeutic that has been revisited to treat refractory solid tumors producing encouraging results. VCR binds to tubulin and decreases the rate of microtubule dynamics, thus triggering many cellular responses and behaviors. However, the dynamics of these responses and fates are uncharacterized. This study combined systems biology approaches with acute and long-term in vitro experiments to predict key pathways and mechanisms associated with cell fates during and after VCR treatment. Glioblastoma (GBM) cells were treated with clinically relevant doses of VCR, and interconnected cell fates were explored. A correlation matrix based on experimental cell analysis reported strong negative correlations between cell number, nuclear irregularities, senescence, or apoptosis, depending on the cells' genetic makeup and treatment regimen. P53 would be essential in all analyzed processes according to topological network analysis. Furthermore, despite the high acute sensitivity, both cell lines re-growth in the long term after a single VCR treatment, especially in those populations with high levels of autophagy. These multiple responses may also be triggered in patients' exposed tumors, which should be considered to allow the rational design of VCR protocols, including modulators of the cell fates and pathways mentioned above.


Glioblastoma , Humans , Apoptosis , Genetic Background , Glioblastoma/genetics , Glioblastoma/drug therapy , Tubulin , Tumor Suppressor Protein p53/genetics , Vincristine/pharmacology , Cellular Senescence , Mitosis
7.
Purinergic Signal ; 18(4): 481-494, 2022 12.
Article En | MEDLINE | ID: mdl-35939198

Glioblastoma (GBM) is the most aggressive and lethal among the primary brain tumors, with a low survival rate and resistance to radio and chemotherapy. The P2Y12 is an adenosine diphosphate (ADP) purinergic chemoreceptor, found mainly in platelets. In cancer cells, its activation has been described to induce proliferation and metastasis. Bearing in mind the need to find new treatments for GBM, this study aimed to investigate the role of the P2Y12R in the proliferation and migration of GBM cells, as well as to evaluate the expression of this receptor in patients' data obtained from the TCGA data bank. Here, we used the P2Y12R antagonist, ticagrelor, which belongs to the antiplatelet agent's class. The different GBM cells (cell line and patient-derived cells) were treated with ticagrelor, with the agonist, ADP, or both, and the effects on cell proliferation, colony formation, ADP hydrolysis, cell cycle and death, migration, and cell adhesion were analyzed. The results showed that ticagrelor decreased the viability and the proliferation of GBM cells. P2Y12R antagonism also reduced colony formation and migration potentials, with alterations on the expression of metalloproteinases, and induced autophagy in GBM cells. Changes were observed at the cell cycle level, and only the U251 cell line showed a significant reduction in the ADP hydrolysis profile. TCGA data analysis showed a higher expression of P2Y12R in gliomas samples when compared to the other tumors. These data demonstrate the importance of the P2Y12 receptor in gliomas development and reinforce its potential as a pharmacological target for glioma treatment.


Glioblastoma , Humans , Ticagrelor/metabolism , Ticagrelor/pharmacology , Adenosine Diphosphate/metabolism , Glioblastoma/drug therapy , Blood Platelets , Autophagy , Cell Proliferation , Receptors, Purinergic P2Y12/metabolism , Purinergic P2Y Receptor Antagonists/metabolism
8.
Mol Cell Biochem ; 477(8): 2047-2057, 2022 Aug.
Article En | MEDLINE | ID: mdl-35429327

As alterations in purinergic signaling have been observed in bladder diseases, we aimed to assess the potential prognostic role of purinergic receptors in bladder cancer in a translational approach based on clinical databases and in vitro data. The prognostic role of purinergic receptors in the survival of patients with bladder cancer and the expression profile of the altered P2 receptors in normal and in tumor samples were determined using The Cancer Genome Atlas databank. In T24 and RT4 human bladder cancer cell lines, the P2 purinergic receptors were characterized by RT-PCR and RT-qPCR analysis including radiotherapy exposure as treatment. The cell number and the cumulative population doubling were also assessed. The expression profile of P2X6 receptor in the cancer pathological stage and in the nodal metastasis status was in agreement with Kaplan-Meier analysis, indicating that high expression of this receptor was related to an increased survival rate in patients with bladder cancer. Of all the P2 receptors expressed on T24 cell line, P2X6 presented high expression after radiotherapy, while it was not altered in RT4 cells. In addition, irradiation promoted a decrease of T24 cell number, but did not change the cell number of RT4 after the same time and radiation dose. Along 7 days after irradiation exposure, both cells regrew. However, while P2X6 receptor was downregulated in T24 cells, it was upregulated in RT4 cells. Our findings indicated that high P2X6 receptor expression induced by radiation in T24 cell line may predict a good survival prognostic factor.


Urinary Bladder Neoplasms , Cell Line, Tumor , Gene Expression , Gene Expression Regulation, Neoplastic , Humans , Signal Transduction , Urinary Bladder Neoplasms/pathology
9.
STAR Protoc ; 3(4): 101855, 2022 12 16.
Article En | MEDLINE | ID: mdl-36595941

The muscle fiber morphometric analysis (MusMA) is a protocol to segment and characterize the morphometry of individual cross-sectioned striated muscle fibers. Using a semi-automated Excel spreadsheet, the protocol allows the objective measurement of muscle fibers' subpopulations, aiming to characterize physiopathological conditions related to muscle tissue. The main limitation of MusMA is the need for high-quality tissue slides and images and control samples to set up the analyses.


Muscle Fibers, Skeletal , Mice , Animals , Disease Models, Animal
10.
Sci Rep ; 10(1): 1218, 2020 01 27.
Article En | MEDLINE | ID: mdl-31988337

Zika virus (ZIKV) has been extensively studied since it was linked to congenital malformations, and recent research has revealed that astrocytes are targets of ZIKV. However, the consequences of ZIKV infection, especially to this cell type, remain largely unknown, particularly considering integrative studies aiming to understand the crosstalk among key cellular mechanisms and fates involved in the neurotoxicity of the virus. Here, the consequences of ZIKV infection in iPSC-derived astrocytes are presented. Our results show ROS imbalance, mitochondrial defects and DNA breakage, which have been previously linked to neurological disorders. We have also detected glial reactivity, also present in mice and in post-mortem brains from infected neonates from the Northeast of Brazil. Given the role of glia in the developing brain, these findings may help to explain the observed effects in congenital Zika syndrome related to neuronal loss and motor deficit.


Astrocytes/metabolism , Astrocytes/virology , Zika Virus Infection/metabolism , Animals , Brain/metabolism , DNA Damage/physiology , Humans , Induced Pluripotent Stem Cells/metabolism , Induced Pluripotent Stem Cells/virology , Male , Mice , Mice, Inbred C57BL , Mitochondria/physiology , Mitochondria/virology , Neurons/metabolism , Oxidative Stress/physiology , Zika Virus/metabolism , Zika Virus Infection/physiopathology , Zika Virus Infection/virology
11.
Oncogene ; 39(10): 2055-2068, 2020 03.
Article En | MEDLINE | ID: mdl-31801972

Tumorigenesis is associated with the development of a highly variable pattern of cellular diversity, consequence of genetic and epigenetic diversification, followed by clonal selection and expansion. This process is shaped by the microenvironment and leads to intratumoral heterogeneity, which is characterized by differences between cancer cells in terms of gene expression, phenotypic markers, growth dynamics, and resistance to treatment. Another relevant aspect in intratumor heterogeneity is cell plasticity-the ability of a cell to switch to new identities. In this review, we focus on the mechanisms that regulate cancer cell plasticity within a tumor, and explore the concept of tumor propagating cells, or TPCs, a cancer cell able to propagate/phenocopy the parental tumor and recapitulate tumor heterogeneity. We discuss the influence of the microenvironment and driver mutations on TPCs formation and function, the existence of phenotypically distinct TPC clones within a tumor, the evolution of TPCs with disease progression, and their implications for therapy.


Cell Plasticity , Genetic Heterogeneity , Mutation , Neoplasms/physiopathology , Tumor Microenvironment , Gene Expression Regulation, Neoplastic , Humans , Neoplasms/genetics
12.
Gene ; 678: 33-37, 2018 Dec 15.
Article En | MEDLINE | ID: mdl-30081189

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder (LSD). It is caused by mutations in the IDUA gene, which lead to the accumulation of the glycosaminoglycans dermatan and heparan sulfate. The CRISPR-Cas9 system is a new and powerful tool that allows gene editing at precise points of the genome, resulting in gene correction through the introduction and genomic integration of a wildtype sequence. In this study, we used the CRISPR-Cas9 genome editing technology to correct in vitro the most common mutation causing MPS I. Human fibroblasts homozygous for p.Trp402* (legacy name W402X) were transfected and analyzed for up to one month after treatment. IDUA activity was significantly increased, lysosomal mass was decreased, and next generation sequencing confirmed that a percentage of cells carried the wildtype sequence. As a proof of concept, this study demonstrates that CRISPR-Cas9 genome editing may be used to correct causative mutations in MPS I. LIST OF ABBREVIATIONS.


Fibroblasts/cytology , Gene Editing/methods , Iduronidase/genetics , Mucopolysaccharidosis I/genetics , CRISPR-Cas Systems , Cells, Cultured , Fibroblasts/metabolism , Genetic Therapy , High-Throughput Nucleotide Sequencing , Humans , Mucopolysaccharidosis I/therapy , Mutation , Sequence Analysis, DNA
13.
J Cancer Res Clin Oncol ; 144(3): 469-482, 2018 Mar.
Article En | MEDLINE | ID: mdl-29305710

PURPOSE: Trimodal therapy is a reasonable bladder-preserving option to radical cystectomy. However, many tumors are radioresistive. In this sense, the identification of new prognostic and predictive biomarkers that allow the selection of patients with better responses to radiation therapy would improve outcomes. With the aim of using ecto-5'-nucleotidase/CD73 as a predictive biomarker, the role of this enzyme in the context of radiotherapy in T24 human bladder cancer cell line was investigated. METHODS: T24 cell line was exposure to a single dose of radiation (4 Gray) and trypan blue assay (pharmacological assays of viability/cumulative population doubling), flow cytometry (cell cycle/cell death/active caspase-3/ecto-5'-nucleotidase/CD73 protein staining), DAPI staining (nuclear morphometric assay), RT-PCR and real-time PCR, malachite green method (ectonucleotidase enzymatic assay), and HPLC (analysis of AMP metabolism) were carried out. T24 cell line in which ecto-5'-nucleotidase/CD73 has been completely silenced (5'KO) was also used. RESULTS: The exposure of T24 cell line to a single dose (4 Gray) of radiation-induced cell death and triggered a transitory increase in ecto-5'-nucleotidase/CD73 expression, increased ectonucleotidase activity, and led to adenosine and inosine accumulation in the extracellular medium. Pharmacological inhibition or knocking out ecto-5'-nucleotidase/CD73 rescued cells' proliferative capacity, reducing their sensitivity to radiation. CONCLUSION: Our findings show that the induction of ecto-5'-nucleotidase/CD73 by radiation contributes to the radiosensitivity of T24 cell line.


5'-Nucleotidase/physiology , Radiation Tolerance/genetics , Urinary Bladder Neoplasms/pathology , Urinary Bladder Neoplasms/radiotherapy , 5'-Nucleotidase/genetics , 5'-Nucleotidase/metabolism , Cell Line, Tumor , Cell Proliferation/genetics , Cell Proliferation/radiation effects , GPI-Linked Proteins/genetics , GPI-Linked Proteins/metabolism , GPI-Linked Proteins/physiology , Gene Expression Regulation, Enzymologic/radiation effects , Gene Expression Regulation, Neoplastic/radiation effects , Gene Knockdown Techniques , Humans , Radiation Dosage , Urinary Bladder Neoplasms/genetics , Urinary Bladder Neoplasms/metabolism
14.
Toxicol In Vitro ; 48: 11-25, 2018 Apr.
Article En | MEDLINE | ID: mdl-29288082

Octyl gallate (OG) is an antioxidant that has shown anti-tumor, anti-diabetic and anti-amyloidogenic activities. Mitochondria play an important role in hepatocellular carcinoma, mainly by maintaining accelerated cellular proliferation through the production of ATP. Thus, the mitochondria may be a target for antitumor therapies. Here, we investigated the effects of OG in the hepatocarcinoma cell line (HepG2) and the mechanisms involved. We report, for the first time, that treatment with OG for 24h inhibited HepG2 cell growth by decreasing mitochondrial activity and mass, which led to the reduction of ATP levels. This reduction in the energy supply triggered a decrease in Ki67 protein expression, leading cells to cycle arrest. In addition, treatment with two doses of OG for 48h induced loss of mitochondrial functionality, mitochondrial swelling and apoptosis. Finally, we report that HepG2 cells had no resistance to treatment after multiple doses. Collectively, our findings indicate that metabolic dysregulation and Ki67 protein reduction are key events in the initial anti-proliferative action of OG, whereas mitochondrial swelling and apoptosis induction are involved in the action mechanism of OG after prolonged exposure. This suggests that OG targets mitochondria, thus representing a candidate for further research on therapies for hepatocarcinoma.


Adenosine Triphosphate/metabolism , Apoptosis/drug effects , Cell Cycle Checkpoints/drug effects , Gallic Acid/analogs & derivatives , Ki-67 Antigen/biosynthesis , Mitochondria/drug effects , Cell Nucleus/drug effects , Cell Nucleus/ultrastructure , Cell Proliferation/drug effects , Drug Resistance , Energy Metabolism/drug effects , Gallic Acid/pharmacology , Hep G2 Cells , Humans , Ki-67 Antigen/drug effects , Mitochondrial Swelling/drug effects , Organelles/drug effects , Organelles/ultrastructure , Phagosomes/drug effects
15.
Mol Neurobiol ; 54(2): 888-894, 2017 03.
Article En | MEDLINE | ID: mdl-26780458

Glioblastoma multiforme (GBM) is the most aggressive type of brain tumor, characterized by excessive cell proliferation, resistance to apoptosis, and invasiveness. Due to resistance to currently available treatment options, the prognosis for patients with GBM is very dismal. The activation of gastrin-releasing peptide receptors (GRPR) stimulates GBM cell proliferation, whereas GRPR antagonists induce antiproliferative effects in in vitro and in vivo experimental models of GBM. However, the role of GRPR in regulating other aspects of GBM cell function related to tumor progression remains poorly understood, and previous studies have not used RNA interference techniques as tools to examine GRPR function in GBM. Here, we found that stable GRPR knockdown by a lentiviral vector using a short hairpin interfering RNA sequence in human A172 GBM cells resulted in increased cell size and altered cell cycle dynamics consistent with cell senescence. These changes were accompanied by increases in the content of p53, p21, and p16, activation of epidermal growth factor receptors (EGFR), and a reduction in p38 content. These results increase our understanding of GRPR regulation of GBM cells and further support that GRPR may be a relevant therapeutic target in GBM.


Brain Neoplasms/metabolism , Cellular Senescence/physiology , Glioblastoma/metabolism , Receptors, Bombesin/deficiency , Brain Neoplasms/genetics , Cell Line, Tumor , Cell Proliferation/physiology , Gene Knockdown Techniques , Glioblastoma/genetics , Humans , Male , Middle Aged , Receptors, Bombesin/genetics
16.
Exp Cell Res ; 348(2): 177-183, 2016 Nov 01.
Article En | MEDLINE | ID: mdl-27669643

Chemotherapy acts on cancer cells by producing multiple effects on a cell population including cell cycle arrest, necrosis, apoptosis and senescence. However, often a subpopulation of cells survives and the behavior of this subpopulation, which is responsible for cancer recurrence, remains obscure. Here we investigated the in vitro short- and long-term responses of six glioblastoma cell lines to clinically relevant doses of temozolomide for 5 days followed by 23 days of recovery, mimicking the standard schedule used in glioblastoma patient for this drug. These cells presented different profiles of sensitivity to temozolomide with varying levels of cell cycle arrest, autophagy and senescence, followed by a regrowth of the surviving cells. The initial reduction in cell number and the subsequent regrowth was analyzed with four new parameters applied to Cumulative Population Doubling (CPD) curves that describe the overall sensitivity of the population and the characteristic of the regrowth: the relative end point CPD (RendCPD); the relative Area Under Curve (rAUC); the Relative Time to Cross a Threshold (RTCT); and the Relative Proliferation Rate (RPR). Surprisingly, the kinetics of regrowth were not predicted by the mechanisms activated after treatment nor by the acute or overall sensitivity. With this study we added new parameters that describe key responses of glioblastoma cell populations to temozolomide treatment. These parameters can also be applied to other cell types and treatments and will help to understand the behavior of the surviving cancer cells after treatment and shed light on studies of cancer resistance and recurrence.


Dacarbazine/analogs & derivatives , Glioblastoma/pathology , Animals , Cell Count , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Dacarbazine/pharmacology , Humans , Kinetics , Mice , Temozolomide
17.
Mol Pharmacol ; 90(3): 371-84, 2016 Sep.
Article En | MEDLINE | ID: mdl-27436127

Autophagy is a catabolic process that is largely regulated by extracellular and intracellular signaling pathways that are central to cellular metabolism and growth. Mounting evidence has shown that ion channels and transporters are important for basal autophagy functioning and influence autophagy to handle stressful situations. Besides its role in cell proliferation and apoptosis, intracellular Ca(2+) is widely recognized as a key regulator of autophagy, acting through the modulation of pathways such as the mechanistic target of rapamycin complex 1, calcium/calmodulin-dependent protein kinase kinase 2, and protein kinase C. Proper spatiotemporal Ca(2+) availability, coupled with a controlled ionic flow among the extracellular milieu, storage compartments, and the cytosol, is critical in determining the role played by Ca(2+) on autophagy and on cell fate. The crosstalk between Ca(2+) and autophagy has a central role in cellular homeostasis and survival during several physiologic and pathologic conditions. Here we review the main findings concerning the mechanisms and roles of Ca(2+)-modulated autophagy, focusing on human disorders ranging from cancer to neurologic diseases and immunity. By identifying mechanisms, players, and pathways that either induce or suppress autophagy, new promising approaches for preventing and treating human disorders emerge, including those based on the modulation of Ca(2+)-mediated autophagy.


Autophagy , Calcium Signaling , Disease , Calcium/metabolism , Central Nervous System/metabolism , Humans , Models, Biological
18.
Autophagy ; 11(7): 1099-113, 2015.
Article En | MEDLINE | ID: mdl-25701485

Autophagy and senescence have been described as central features of cell biology, but the interplay between these mechanisms remains obscure. Using a therapeutically relevant model of DNA damage-induced senescence in human glioma cells, we demonstrated that acute treatment with temozolomide induces DNA damage, a transitory activation of PRKAA/AMPK-ULK1 and MAPK14/p38 and the sustained inhibition of AKT-MTOR. This produced a transient induction of autophagy, which was followed by senescence. However, at the single cell level, this coordinated transition was not observed, and autophagy and senescence were triggered in a very heterogeneous manner. Indeed, at a population level, autophagy was highly negatively correlated with senescence markers, while in single cells this correlation did not exist. The inhibition of autophagy triggered apoptosis and decreased senescence, while its activation increased temozolomide-induced senescence, showing that DNA damage-induced autophagy acts by suppressing apoptosis.


Autophagy , Cellular Senescence , DNA Damage , Single-Cell Analysis/methods , AMP-Activated Protein Kinases/metabolism , Apoptosis/drug effects , Autophagy/drug effects , Autophagy-Related Protein-1 Homolog , Cell Cycle Checkpoints/drug effects , Cell Line, Tumor , Cellular Senescence/drug effects , Dacarbazine/analogs & derivatives , Dacarbazine/pharmacology , Enzyme Activation/drug effects , Glioma/enzymology , Glioma/pathology , Green Fluorescent Proteins/metabolism , Humans , Intracellular Signaling Peptides and Proteins/metabolism , Models, Biological , Phenotype , Protein Serine-Threonine Kinases/metabolism , Sirolimus/pharmacology , TOR Serine-Threonine Kinases/metabolism , Temozolomide , Time Factors , p38 Mitogen-Activated Protein Kinases/metabolism
19.
Mol Biol Cell ; 25(19): 2905-18, 2014 Oct 01.
Article En | MEDLINE | ID: mdl-25103241

In cervical cancer, HPV infection and disruption of mechanisms involving cell growth, differentiation, and apoptosis are strictly linked with tumor progression and invasion. Tumor microenvironment is ATP and adenosine rich, suggesting a role for purinergic signaling in cancer cell growth and death. Here we investigate the effect of extracellular ATP on human cervical cancer cells. We find that extracellular ATP itself has a small cytotoxic effect, whereas adenosine formed from ATP degradation by ectonucleotidases is the main factor responsible for apoptosis induction. The level of P2 × 7 receptor seemed to define the main cytotoxic mechanism triggered by ATP, since ATP itself eliminated a small subpopulation of cells that express high P2 × 7 levels, probably through its activation. Corroborating these data, blockage or knockdown of P2 × 7 only slightly reduced ATP cytotoxicity. On the other hand, cell viability was almost totally recovered with dipyridamole, an adenosine transporter inhibitor. Moreover, ATP-induced apoptosis and signaling-p53 increase, AMPK activation, and PARP cleavage-as well as autophagy induction were also inhibited by dipyridamole. In addition, inhibition of adenosine conversion into AMP also blocked cell death, indicating that metabolization of intracellular adenosine originating from extracellular ATP is responsible for the main effects of the latter in human cervical cancer cells.


Adenosine Monophosphate/biosynthesis , Adenosine Triphosphate/pharmacology , Adenosine/metabolism , Apoptosis/drug effects , Uterine Cervical Neoplasms/drug therapy , AMP-Activated Protein Kinases/metabolism , Adenosine Triphosphate/metabolism , Autophagy/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Dipyridamole/pharmacology , Female , HeLa Cells , Humans , Nucleoside Transport Proteins/antagonists & inhibitors , Poly(ADP-ribose) Polymerases/metabolism , RNA Interference , RNA, Messenger/biosynthesis , RNA, Small Interfering , Receptors, Purinergic P2X7/genetics , Receptors, Purinergic P2X7/metabolism , Tumor Microenvironment , Tumor Suppressor Protein p53/biosynthesis
20.
Neurochem Res ; 39(5): 973-84, 2014 May.
Article En | MEDLINE | ID: mdl-24706093

Several researchers have recently used C6 cells to evaluate functional properties of high-affinity glutamate transporters. However, it has been demonstrated that this lineage suffers several morphological and biochemical alterations according to the number of passages in culture. Currently, there are no reports showing whether functional properties of high-affinity glutamate transporters comply with these sub culturing-dependent modifications. The present study aimed to compare the functional properties of high-affinity glutamate transporters expressed in early (EPC6) and late (LPC6) passage C6 cells through a detailed pharmacological and biochemical characterization. Between 60-180 min of L-[(3)H]glu incubation, LPC6 presented an intracellular [(3)H] 55% lower than EPC6. Both cultures showed a time-dependent increase of intracellular [(3)H] reaching maximal levels at 120 min. Cultures incubated with D-[(3)H]asp showed a time-dependent increase of [(3)H] until 180 min. Moreover, LPC6 have a D-[(3)H]asp-derived intracellular [(3)H] 30-45% lower than EPC6 until 120 min. Only EAAT3 was immunodetected in cultures and its total content was equal between them. PMA-stimulated EAAT3 trafficking to membrane increased 50% of L-[(3)H]glu-derived intracellular [(3)H] in EPC6 and had no effect in LPC6. LPC6 displayed characteristics that resemble senescence, such as high ß-Gal staining, cell enlargement and increase of large and regular nuclei. Our results demonstrated that LPC6 exhibited glutamate uptake impairment, which may have occurred due to its inability to mobilize EAAT3 to cell membrane. This profile might be related to senescent process observed in this culture. Our results suggest that LPC6 cells are an inappropriate glial cellular model to investigate the functional properties of high-affinity glutamate transporters.


Aspartic Acid/metabolism , Cellular Senescence/physiology , Glutamic Acid/metabolism , Animals , Glioma/metabolism , Rats, Wistar , Tritium , Tumor Cells, Cultured
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