Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 60
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Elife ; 102021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34517941

RESUMO

Microsatellite expansions of CCTG repeats in the cellular nucleic acid-binding protein (CNBP) gene leads to accumulation of toxic RNA and have been associated with myotonic dystrophy type 2 (DM2). However, it is still unclear whether the dystrophic phenotype is also linked to CNBP decrease, a conserved CCHC-type zinc finger RNA-binding protein that regulates translation and is required for mammalian development. Here, we show that depletion of Drosophila CNBP in muscles causes ageing-dependent locomotor defects that are correlated with impaired polyamine metabolism. We demonstrate that the levels of ornithine decarboxylase (ODC) and polyamines are significantly reduced upon dCNBP depletion. Of note, we show a reduction of the CNBP-polyamine axis in muscles from DM2 patients. Mechanistically, we provide evidence that dCNBP controls polyamine metabolism through binding dOdc mRNA and regulating its translation. Remarkably, the locomotor defect of dCNBP-deficient flies is rescued by either polyamine supplementation or dOdc1 overexpression. We suggest that this dCNBP function is evolutionarily conserved in vertebrates with relevant implications for CNBP-related pathophysiological conditions.


Assuntos
Proteínas de Drosophila/metabolismo , Atividade Motora/genética , Atividade Motora/fisiologia , Poliaminas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Animais , Animais Geneticamente Modificados , Linhagem Celular , Regulação para Baixo/fisiologia , Proteínas de Drosophila/genética , Drosophila melanogaster , Regulação da Expressão Gênica/efeitos dos fármacos , Células HEK293 , Humanos , Músculo Esquelético/metabolismo , Distrofia Miotônica/genética , Distrofia Miotônica/metabolismo , Biossíntese de Proteínas , Putrescina/farmacologia , Interferência de RNA , Proteínas de Ligação a RNA/genética , Espermidina/farmacologia
2.
Oncogene ; 40(43): 6143-6152, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34508175

RESUMO

MYCN drives aggressive behavior and refractoriness to chemotherapy, in several tumors. Since MYCN inactivation in clinical settings is not achievable, alternative vulnerabilities of MYCN-driven tumors need to be explored to identify more effective and less toxic therapies. We previously demonstrated that PARP inhibitors enhance MYCN-induced replication stress and promote mitotic catastrophe, counteracted by CHK1. Here, we showed that PARP and CHK1 inhibitors synergized to induce death in neuroblastoma cells and in primary cultures of SHH-dependent medulloblastoma, their combination being more effective in MYCN amplified and MYCN overexpressing cells compared to MYCN non-amplified cells. Although the MYCN amplified IMR-32 cell line carrying the p.Val2716Ala ATM mutation showed the highest sensitivity to the drug combination, this was not related to ATM status, as indicated by CRISPR/Cas9-based correction of the mutation. Suboptimal doses of the CHK1 inhibitor MK-8776 plus the PARP inhibitor olaparib led to a MYCN-dependent accumulation of DNA damage and cell death in vitro and significantly reduced the growth of four in vivo models of MYCN-driven tumors, without major toxicities. Our data highlight the combination of PARP and CHK1 inhibitors as a new potential chemo-free strategy to treat MYCN-driven tumors, which might be promptly translated into clinical trials.

3.
Cells ; 10(8)2021 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-34440719

RESUMO

Neuroblastoma (NB) is a common malignant solid tumor in children and accounts for 15% of childhood cancer mortality. Amplification of the N-Myc oncogene is a well-established poor prognostic marker in NB patients and strongly correlates with higher tumor aggression and resistance to treatment. New therapies for patients with N-Myc-amplified NB need to be developed. After treating NB cells with BSAO/SPM, the detection of apoptosis was determined after annexin V-FITC labeling and DNA staining with propidium iodide. The mitochondrial membrane potential activity was checked, labeling cells with the probe JC-1 dye. We analyzed, by real-time RT-PCR, the transcript of genes involved in the apoptotic process, to determine possible down- or upregulation of mRNAs after the treatment on SJNKP and the N-Myc-amplified IMR5 cell lines with BSAO/SPM. The experiments were carried out considering the proapoptotic genes Tp53 and caspase-3. After treatment with BSAO/SPM, both cell lines displayed increased mRNA levels for all these proapoptotic genes. Western blotting analysis with PARP and caspase-3 antibody support that BSAO/SPM treatment induces high levels of apoptosis in cells. The major conclusion is that BSAO/SPM treatment leads to antiproliferative and cytotoxic activity of both NB cell lines, associated with activation of apoptosis.


Assuntos
Amina Oxidase (contendo Cobre)/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , MicroRNAs/metabolismo , Proteína Proto-Oncogênica N-Myc/metabolismo , Neuroblastoma/tratamento farmacológico , Espermina/farmacologia , Proteína Supressora de Tumor p53/metabolismo , Animais , Caspase 3/genética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Amplificação de Genes , Regulação Neoplásica da Expressão Gênica , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , MicroRNAs/genética , Proteína Proto-Oncogênica N-Myc/genética , Neuroblastoma/enzimologia , Neuroblastoma/genética , Ratos Wistar , Transdução de Sinais , Espermina/metabolismo , Proteína Supressora de Tumor p53/genética
4.
Front Cell Dev Biol ; 9: 638508, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33898425

RESUMO

The Hedgehog (Hh) signaling pathway plays a crucial role in normal embryonic development and adult tissue homeostasis. On the other end, dysregulated Hh signaling triggers a prolonged mitogenic response that may prompt abnormal cell proliferation, favoring tumorigenesis. Indeed, about 30% of medulloblastomas (MBs), the most common malignant childhood cerebellar tumors, exhibit improper activation of the Hh signaling. The oncosuppressor KCASH2 has been described as a suppressor of the Hh signaling pathway, and low KCASH2 expression was observed in Hh-dependent MB tumor. Therefore, the study of the modulation of KCASH2 expression may provide fundamental information for the development of new therapeutic approaches, aimed to restore physiological KCASH2 levels and Hh inhibition. To this end, we have analyzed the TATA-less KCASH2 proximal promoter and identified key transcriptional regulators of this gene: Sp1, a TF frequently overexpressed in tumors, and the tumor suppressor p53. Here, we show that in WT cells, Sp1 binds KCASH2 promoter on several putative binding sites, leading to increase in KCASH2 expression. On the other hand, p53 is involved in negative regulation of KCASH2. In this context, the balance between p53 and Sp1 expression, and the interplay between these two proteins determine whether Sp1 acts as an activator or a repressor of KCASH2 transcription. Indeed, in p53-/- MEF and p53 mutated tumor cells, we hypothesize that Sp1 drives promoter methylation through increased expression of the DNA methyltransferase 1 (DNMT1) and reduces KCASH2 transcription, which can be reversed by Sp1 inhibition or use of demethylating agents. We suggest therefore that downregulation of KCASH2 expression in tumors could be mediated by gain of Sp1 activity and epigenetic silencing events in cells where p53 functionality is lost. This work may open new venues for novel therapeutic multidrug approaches in the treatment of Hh-dependent tumors carrying p53 deficiency.

5.
Cell Death Dis ; 12(4): 316, 2021 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-33767160

RESUMO

The prognosis of locally advanced colorectal cancer (CRC) is currently unsatisfactory. This is mainly due to drug resistance, recurrence, and subsequent metastatic dissemination, which are sustained by the cancer stem cell (CSC) population. The main driver of the CSC gene expression program is Wnt signaling, and previous reports indicate that Wnt3a can activate p38 MAPK. Besides, p38 was shown to feed into the canonical Wnt/ß-catenin pathway. Here we show that patient-derived locally advanced CRC stem cells (CRC-SCs) are characterized by increased expression of p38α and are "addicted" to its kinase activity. Of note, we found that stage III CRC patients with high p38α levels display reduced disease-free and progression-free survival. Extensive molecular analysis in patient-derived CRC-SC tumorspheres and APCMin/+ mice intestinal organoids revealed that p38α acts as a ß-catenin chromatin-associated kinase required for the regulation of a signaling platform involved in tumor proliferation, metastatic dissemination, and chemoresistance in these CRC model systems. In particular, the p38α kinase inhibitor ralimetinib, which has already entered clinical trials, promoted sensitization of patient-derived CRC-SCs to chemotherapeutic agents commonly used for CRC treatment and showed a synthetic lethality effect when used in combination with the MEK1 inhibitor trametinib. Taken together, these results suggest that p38α may be targeted in CSCs to devise new personalized CRC treatment strategies.


Assuntos
Cromatina/metabolismo , Neoplasias Colorretais/tratamento farmacológico , Proteína Quinase 14 Ativada por Mitógeno/metabolismo , Células-Tronco Neoplásicas/metabolismo , Organoides/metabolismo , Processamento de Proteína Pós-Traducional/genética , beta Catenina/metabolismo , Neoplasias Colorretais/genética , Humanos , Prognóstico
6.
Mol Oncol ; 15(2): 523-542, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32920979

RESUMO

Persistent mortality rates of medulloblastoma (MB) and severe side effects of the current therapies require the definition of the molecular mechanisms that contribute to tumor progression. Using cultured MB cancer stem cells and xenograft tumors generated in mice, we show that low expression of miR-326 and its host gene ß-arrestin1 (ARRB1) promotes tumor growth enhancing the E2F1 pro-survival function. Our models revealed that miR-326 and ARRB1 are controlled by a bivalent domain, since the H3K27me3 repressive mark is found at their regulatory region together with the activation-associated H3K4me3 mark. High levels of EZH2, a feature of MB, are responsible for the presence of H3K27me3. Ectopic expression of miR-326 and ARRB1 provides hints into how their low levels regulate E2F1 activity. MiR-326 targets E2F1 mRNA, thereby reducing its protein levels; ARRB1, triggering E2F1 acetylation, reverses its function into pro-apoptotic activity. Similar to miR-326 and ARRB1 overexpression, we also show that EZH2 inhibition restores miR-326/ARRB1 expression, limiting E2F1 pro-proliferative activity. Our results reveal a new regulatory molecular axis critical for MB progression.

7.
Cell Death Dis ; 11(12): 1045, 2020 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-33303756

RESUMO

Eukaryotic Translation Initiation Factor 5A (EIF5A) is a translation factor regulated by hypusination, a unique posttranslational modification catalyzed by deoxyhypusine synthetase (DHPS) and deoxyhypusine hydroxylase (DOHH) starting from the polyamine spermidine. Emerging data are showing that hypusinated EIF5A regulates key cellular processes such as autophagy, senescence, polyamine homeostasis, energy metabolism, and plays a role in cancer. However, the effects of EIF5A inhibition in preclinical cancer models, the mechanism of action, and specific translational targets are still poorly understood. We show here that hypusinated EIF5A promotes growth of colorectal cancer (CRC) cells by directly regulating MYC biosynthesis at specific pausing motifs. Inhibition of EIF5A hypusination with the DHPS inhibitor GC7 or through lentiviral-mediated knockdown of DHPS or EIF5A reduces the growth of various CRC cells. Multiplex gene expression analysis reveals that inhibition of hypusination impairs the expression of transcripts regulated by MYC, suggesting the involvement of this oncogene in the observed effect. Indeed, we demonstrate that EIF5A regulates MYC elongation without affecting its mRNA content or protein stability, by alleviating ribosome stalling at five distinct pausing motifs in MYC CDS. Of note, we show that blockade of the hypusination axis elicits a remarkable growth inhibitory effect in preclinical models of CRC and significantly reduces the size of polyps in APCMin/+ mice, a model of human familial adenomatous polyposis (FAP). Together, these data illustrate an unprecedented mechanism, whereby the tumor-promoting properties of hypusinated EIF5A are linked to its ability to regulate MYC elongation and provide a rationale for the use of DHPS/EIF5A inhibitors in CRC therapy.


Assuntos
Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Lisina/análogos & derivados , Fatores de Iniciação de Peptídeos/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas de Ligação a RNA/metabolismo , Polipose Adenomatosa do Colo/genética , Polipose Adenomatosa do Colo/patologia , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Linhagem Celular Tumoral , Proliferação de Células/genética , Neoplasias Colorretais/genética , Regulação para Baixo , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Lisina/metabolismo , Camundongos Nus , Fases de Leitura Aberta/genética , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/antagonistas & inibidores , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Fatores de Iniciação de Peptídeos/química , Peptídeos/metabolismo , Poliaminas/metabolismo , Biossíntese de Proteínas , Proteínas de Ligação a RNA/química
8.
Oncogenesis ; 9(10): 93, 2020 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-33071287

RESUMO

Unfolded protein response (UPR) is a conserved adaptive response that tries to restore protein homeostasis after endoplasmic reticulum (ER) stress. Recent studies highlighted the role of UPR in acute leukemias and UPR targeting has been suggested as a therapeutic approach. Aberrant Notch signaling is a common feature of T-cell acute lymphoblastic leukemia (T-ALL), as downregulation of Notch activity negatively affects T-ALL cell survival, leading to the employment of Notch inhibitors in T-ALL therapy. Here we demonstrate that Notch3 is able to sustain UPR in T-ALL cells, as Notch3 silencing favored a Bip-dependent IRE1α inactivation under ER stress conditions, leading to increased apoptosis via upregulation of the ER stress cell death mediator CHOP. By using Juglone, a naturally occurring naphthoquinone acting as an anticancer agent, to decrease Notch3 expression and induce ER stress, we observed an increased ER stress-associated apoptosis. Altogether our results suggest that Notch3 inhibition may prevent leukemia cells from engaging a functional UPR needed to compensate the Juglone-mediated ER proteotoxic stress. Notably, in vivo administration of Juglone to human T-ALL xenotransplant models significantly reduced tumor growth, finally fostering the exploitation of Juglone-dependent Notch3 inhibition to perturb the ER stress/UPR signaling in Notch3-dependent T-ALL subsets.

9.
ChemMedChem ; 15(23): 2264-2268, 2020 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-32946182

RESUMO

The Wnt/ß-catenin pathway is often found deregulated in cancer. The aberrant accumulation of ß-catenin in the cell nucleus results in the development of various malignancies. Specific drugs against this signaling pathway for clinical treatments have not been approved yet. Herein we report inhibitors of ß-catenin signaling of potential therapeutic value as anticancer agents. Ethyl 4-((4-(trifluoromethyl)phenyl)sulfonamido)benzoate (compound 14) inhibits the effect on Wnt reporter with an IC50 value of 7.0 µM, significantly reduces c-MYC levels, inhibits HCT116 colon cancer cell growth (IC50 20.2 µM), does not violate Lipinski and Veber rules, and shows predicted Caco-2 and MDCK cell permeability Papp >500 nm s-1 . Compound 14 seems to have potential for the development of new anticancer therapies.


Assuntos
Antineoplásicos/farmacologia , Proteínas Proto-Oncogênicas c-myc/antagonistas & inibidores , Sulfonamidas/farmacologia , beta Catenina/antagonistas & inibidores , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , Proteínas Proto-Oncogênicas c-myc/metabolismo , Sulfonamidas/síntese química , Sulfonamidas/química , Via de Sinalização Wnt/efeitos dos fármacos , beta Catenina/metabolismo
10.
Biomolecules ; 10(5)2020 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-32397196

RESUMO

The blooming of nanotechnology has made available a limitless landscape of solutions responding to crucial issues in many fields and, nowadays, a wide choice of nanotechnology-based strategies can be adopted to circumvent the limitations of conventional therapies for cancer. Herein, the current stage of nanotechnological applications for cancer management is summarized encompassing the core nanomaterials as well as the available chemical-physical approaches for their surface functionalization and drug ligands as possible therapeutic agents. The use of nanomaterials as vehicles to delivery various therapeutic substances is reported emphasizing advantages, such as the high drug loading, the enhancement of the pay-load half-life and bioavailability. Particular attention was dedicated to highlight the importance of nanomaterial intrinsic features. Indeed, the ability of combining the properties of the transported drug with the ones of the nano-sized carrier can lead to multifunctional theranostic tools. In this view, fluorescence of carbon quantum dots, optical properties of gold nanoparticle and superparamagnetism of iron oxide nanoparticles, are fundamental examples. Furthermore, smart anticancer devices can be developed by conjugating enzymes to nanoparticles, as in the case of bovine serum amine oxidase (BSAO) and gold nanoparticles. The present review is aimed at providing an overall vision on nanotechnological strategies to face the threat of human cancer, comprising opportunities and challenges.


Assuntos
Antineoplásicos/uso terapêutico , Nanotecnologia/métodos , Adsorção , Animais , Antineoplásicos/farmacologia , Tecnologia Biomédica , Humanos , Nanopartículas/química
11.
Front Oncol ; 10: 560, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32457828

RESUMO

Extensive molecular characterization of human colorectal cancer (CRC) via Next Generation Sequencing (NGS) indicated that genetic or epigenetic dysregulation of a relevant, but limited, number of molecular pathways typically occurs in this tumor. The molecular picture of the disease is significantly complicated by the frequent occurrence of individually rare genetic aberrations, which expand tumor heterogeneity. Inter- and intratumor molecular heterogeneity is very likely responsible for the remarkable individual variability in the response to conventional and target-driven first-line therapies, in metastatic CRC (mCRC) patients, whose median overall survival remains unsatisfactory. Implementation of an extensive molecular characterization of mCRC in the clinical routine does not yet appear feasible on a large scale, while multigene panel sequencing of most commonly mutated oncogene/oncosuppressor hotspots is more easily achievable. Here, we report that clinical multigene panel sequencing performed for anti-EGFR therapy predictive purposes in 639 formalin-fixed paraffin-embedded (FFPE) mCRC specimens revealed previously unknown pairwise mutation associations and a high proportion of cases carrying actionable gene mutations. Most importantly, a simple principal component analysis directed the delineation of a new molecular stratification of mCRC patients in eight groups characterized by non-random, specific mutational association patterns (MAPs), aggregating samples with similar biology. These data were validated on a The Cancer Genome Atlas (TCGA) CRC dataset. The proposed stratification may provide great opportunities to direct more informed therapeutic decisions in the majority of mCRC cases.

12.
Exp Ther Med ; 19(2): 1511-1521, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32010332

RESUMO

Aged garlic extract (AGE) has been demonstrated to have therapeutic properties in tumors; however its mechanisms of action have not yet been fully elucidated. A previous study revealed that AGE exerts an anti-proliferative effect on a panel of both sensitive [wild-type (WT)] and multidrug-resistant (MDR) human cancer cells. Following treatment of the cells with AGE, cytofluorimetric analysis revealed the occurrence of dose-dependent mitochondrial membrane depolarization (MMD). In this study, in order to further clarify the mechanisms of action of AGE, the effects of AGE on mitochondria isolated from rat liver mitochondria (RLM) were also examined. AGE induced an effect on the components of the electrochemical gradient (ΔµH +), mitochondrial membrane potential (ΔΨm) and mitochondrial electrochemical gradient (ΔpHm). The mitochondrial membrane dysfunctions of RLM induced by AGE, namely the decrease in both membrane potential and chemical gradient were associated with a higher oxidation of both the endogenous glutathione and pyridine nucleotide content. To confirm the anti-proliferative effects of AGE, experiments were performed on the human neuroblastoma (NB) cancer cells, SJ-N-KP and the MYCN-amplified IMR5 cells, using its derivative S-allyl-L-cysteine (SAC), with the aim of providing evidence of the anticancer activity of this compound and its possible molecular mechanism as regards the induction of cytotoxicity. Following treatment of the cells with SAC at 20 mM, cell viability was determined by MTT assay and apoptosis was detected by flow cytometry, using Annexin V-FITC labeling. The percentages of cells undergoing apoptosis was found to be 48.0% in the SJ-N-KP and 50.1% in the IMR5 cells. By cytofluorimetric analysis, it was suggested that the target of SAC are the mitochondria. Mitochondrial activity was examined by labeling the cells with the probe, 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylimidacarbocyanine iodide (JC-1). Following treatment with SAC at 50 mM, both NB cell lines exhibited a marked increase in MMD. On the whole, the findings of this study indicate that both natural products, AGE and SAC, cause cytotoxicity to tumor cells via the induction of mitochondrial permeability transition (MPT).

13.
Cancers (Basel) ; 12(2)2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32019099

RESUMO

Glioblastoma multiforme (GB) is the most malignant primary brain tumor in humans, with an overall survival of approximatively 15 months. The molecular heterogeneity of GB, as well as its rapid progression, invasiveness and the occurrence of drug-resistant cancer stem cells, limits the efficacy of the current treatments. In order to develop an innovative therapeutic strategy, it is mandatory to identify and characterize new molecular players responsible for the GB malignant phenotype. In this study, the RNA-binding ubiquitin ligase MEX3A was selected from a gene expression analysis performed on publicly available datasets, to assess its biological and still-unknown activity in GB tumorigenesis. We find that MEX3A is strongly up-regulated in GB specimens, and this correlates with very low protein levels of RIG-I, a tumor suppressor involved in differentiation, apoptosis and innate immune response. We demonstrate that MEX3A binds RIG-I and induces its ubiquitylation and proteasome-dependent degradation. Further, the genetic depletion of MEX3A leads to an increase of RIG-I protein levels and results in the suppression of GB cell growth. Our findings unveil a novel molecular mechanism involved in GB tumorigenesis and suggest MEX3A and RIG-I as promising therapeutic targets in GB.

14.
Cell Rep ; 30(6): 1735-1752.e7, 2020 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-32049007

RESUMO

The antidiabetic drug phenformin displays potent anticancer activity in different tumors, but its mechanism of action remains elusive. Using Shh medulloblastoma as model, we show here that at clinically relevant concentrations, phenformin elicits a significant therapeutic effect through a redox-dependent but complex I-independent mechanism. Phenformin inhibits mitochondrial glycerophosphate dehydrogenase (mGPD), a component of the glycerophosphate shuttle, and causes elevations of intracellular NADH content. Inhibition of mGPD mimics phenformin action and promotes an association between corepressor CtBP2 and Gli1, thereby inhibiting Hh transcriptional output and tumor growth. Because ablation of CtBP2 abrogates the therapeutic effect of phenformin in mice, these data illustrate a biguanide-mediated redox/corepressor interplay, which may represent a relevant target for tumor therapy.


Assuntos
Antineoplásicos/uso terapêutico , Proteínas Correpressoras/efeitos dos fármacos , Proteínas Hedgehog/efeitos dos fármacos , Hipoglicemiantes/uso terapêutico , Neoplasias/tratamento farmacológico , Fenformin/uso terapêutico , Animais , Antineoplásicos/farmacologia , Humanos , Hipoglicemiantes/farmacologia , Camundongos , Fenformin/farmacologia
15.
Sci Rep ; 9(1): 19623, 2019 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-31873117

RESUMO

Growth and patterning of the cerebellum is compromised if granule cell precursors do not properly expand and migrate. During embryonic and postnatal cerebellar development, the Hedgehog pathway tightly regulates granule cell progenitors to coordinate appropriate foliation and lobule formation. Indeed, granule cells impairment or defects in the Hedgehog signaling are associated with developmental, neurodegenerative and neoplastic disorders. So far, scant and inefficient cellular models have been available to study granule cell progenitors, in vitro. Here, we validated a new culture method to grow postnatal granule cell progenitors as hedgehog-dependent neurospheres with prolonged self-renewal and ability to differentiate into granule cells, under appropriate conditions. Taking advantage of this cellular model, we provide evidence that Ptch1-KO, but not the SMO-M2 mutation, supports constitutive and cell-autonomous activity of the hedgehog pathway.


Assuntos
Diferenciação Celular , Cerebelo/metabolismo , Proteínas Hedgehog , Células-Tronco Neurais/metabolismo , Transdução de Sinais , Receptor Smoothened , Animais , Cerebelo/citologia , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Camundongos , Camundongos Knockout , Células-Tronco Neurais/citologia , Receptor Smoothened/genética , Receptor Smoothened/metabolismo
16.
Oncogenesis ; 8(11): 64, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31685809

RESUMO

Medulloblastoma (MB) is the most common malignant childhood brain tumor. About 30% of all MBs belong to the I molecular subgroup, characterized by constitutive activation of the Sonic Hedgehog (Hh) pathway. The Hh pathway is involved in several fundamental processes during embryogenesis and in adult life and its deregulation may lead to cerebellar tumorigenesis. Indeed, Hh activity must be maintained via a complex network of activating and repressor signals. One of these repressor signals is KCASH2, belonging to the KCASH family of protein, which acts as negative regulators of the Hedgehog signaling pathway during cerebellar development and differentiation. KCASH2 leads HDAC1 to degradation, allowing hyperacetylation and inhibition of transcriptional activity of Gli1, the main effector of the Hh pathway. In turn, the KCASH2 loss leads to persistent Hh activity and eventually tumorigenesis. In order to better characterize the physiologic role and modulation mechanisms of KCASH2, we have searched through a proteomic approach for new KCASH2 interactors, identifying Potassium Channel Tetramerization Domain Containing 15 (KCTD15). KCTD15 is able to directly interact with KCASH2, through its BTB/POZ domain. This interaction leads to increase KCASH2 stability which implies a reduction of the Hh pathway activity and a reduction of Hh-dependent MB cells proliferation. Here we report the identification of KCTD15 as a novel player in the complex network of regulatory proteins, which modulate Hh pathway, this could be a promising new target for therapeutic approach against MB.

17.
Nat Commun ; 10(1): 3304, 2019 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-31341163

RESUMO

The Hedgehog (Hh) pathway is essential for embryonic development and tissue homeostasis. Aberrant Hh signaling may occur in a wide range of human cancers, such as medulloblastoma, the most common brain malignancy in childhood. Here, we identify endoplasmic reticulum aminopeptidase 1 (ERAP1), a key regulator of innate and adaptive antitumor immune responses, as a previously unknown player in the Hh signaling pathway. We demonstrate that ERAP1 binds the deubiquitylase enzyme USP47, displaces the USP47-associated ßTrCP, the substrate-receptor subunit of the SCFßTrCP ubiquitin ligase, and promotes ßTrCP degradation. These events result in the modulation of Gli transcription factors, the final effectors of the Hh pathway, and the enhancement of Hh activity. Remarkably, genetic or pharmacological inhibition of ERAP1 suppresses Hh-dependent tumor growth in vitro and in vivo. Our findings unveil an unexpected role for ERAP1 in cancer and indicate ERAP1 as a promising therapeutic target for Hh-driven tumors.


Assuntos
Aminopeptidases/fisiologia , Antígenos de Histocompatibilidade Menor/fisiologia , Proteases Específicas de Ubiquitina/metabolismo , Proteínas Contendo Repetições de beta-Transducina/metabolismo , Aminopeptidases/genética , Aminopeptidases/metabolismo , Animais , Carcinogênese/genética , Proteínas Hedgehog/metabolismo , Camundongos , Antígenos de Histocompatibilidade Menor/genética , Antígenos de Histocompatibilidade Menor/metabolismo , Células NIH 3T3 , Estabilidade Proteica , Proteólise , Transdução de Sinais
18.
Int J Oncol ; 54(6): 2080-2094, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31081059

RESUMO

Amine oxidases, which contribute to the regulation of polyamine levels, catalyze the oxidative deamination of polyamines to generate H2O2 and aldehyde(s). In this study, and at least to the best of our knowledge, maize polyamine oxidase (ZmPAO) was used for the first time with the aim of identifying a novel strategy for cancer therapy. The cytotoxicity and the mechanisms of cell death induced by the enzymatic oxidation products of polyamine generated by ZmPAO were investigated. Exogenous spermine and ZmPAO treatment decreased cell viability in a spermine dose­ and time­dependent manner, particularly, the viability of the multidrug­resistant (MDR) colon adenocarcinoma cells, LoVo DX, when compared with drug­sensitive ones (LoVo WT). Further analyses revealed that H2O2 derived from spermine was mainly responsible for the cytotoxicity. Flow cytometric analysis revealed that treatment with ZmPAO and spermine increased the apoptotic population of LoVo WT and LoVo DX cells. In addition, we found that treatment with ZmPAO and spermine markedly reduced mitochondrial membrane potential in the LoVo DX cells, in agreement with the results of cell viability and apoptosis assays. Transmission electron microscopic observations supported the involvement of mitochondrial depolarization in the apoptotic process. Therefore, the dysregulation of polyamine metabolism in tumor cells may be a potential therapeutic target. In addition, the development of MDR tumor cells is recognized as a major obstacle in cancer therapy. Therefore, the design of a novel therapeutic strategy based on the use of this combination may be taken into account, making this approach attractive mainly in treating MDR cancer patients.


Assuntos
Adenocarcinoma/metabolismo , Neoplasias do Colo/metabolismo , Peróxido de Hidrogênio/metabolismo , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/farmacologia , Espermina/farmacologia , Zea mays/enzimologia , Adenocarcinoma/tratamento farmacológico , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Neoplasias do Colo/tratamento farmacológico , Relação Dose-Resposta a Droga , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Sinergismo Farmacológico , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Proteínas de Plantas/farmacologia , Espermidina/farmacologia , Fatores de Tempo
19.
ACS Med Chem Lett ; 10(4): 499-503, 2019 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-30996786

RESUMO

Targeted approaches aiming at modulating NHERF1 activity, rather than its overall expression, would be preferred to preserve the normal functions of this versatile protein. We focused our attention on the NHERF1/PDZ1 domain that governs its membrane recruitment/displacement through a transient phosphorylation switch. We herein report the design and synthesis of novel NHERF1 PDZ1 domain inhibitors. These compounds have potential therapeutic value when used in combination with antagonists of ß-catenin to augment apoptotic death of colorectal cancer cells refractory to currently available Wnt/ß-catenin-targeted agents.

20.
Cells ; 8(2)2019 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-30754726

RESUMO

Hedgehog (Hh) signaling is a critical developmental regulator and its aberrant activation,due to somatic or germline mutations of genes encoding pathway components, causes Basal CellCarcinoma (BCC) and medulloblastoma (MB). A growing effort has been devoted at theidentification of druggable vulnerabilities of the Hedgehog signaling, leading to the identificationof various compounds with variable efficacy and/or safety. Emerging evidence shows that anaberrant polyamine metabolism is a hallmark of Hh-dependent tumors and that itspharmacological inhibition elicits relevant therapeutic effects in clinical or preclinical models ofBCC and MB. We discuss here the current knowledge of polyamine metabolism, its role in cancerand the available targeting strategies. We review the literature about the connection betweenpolyamines and the Hedgehog signaling, and the potential therapeutic benefit of targetingpolyamine metabolism in two malignancies where Hh pathways play a well-established role: BCCand MB.


Assuntos
Carcinoma Basocelular/metabolismo , Carcinoma Basocelular/terapia , Proteínas Hedgehog/metabolismo , Meduloblastoma/metabolismo , Meduloblastoma/terapia , Terapia de Alvo Molecular , Poliaminas/metabolismo , Animais , Carcinogênese/metabolismo , Humanos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...