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1.
Cell Mol Neurobiol ; 43(2): 813-826, 2023 Mar.
Article in English | MEDLINE | ID: mdl-35366170

ABSTRACT

Medulloblastoma is the most common type of pediatric malignant primary brain tumor, and about one-third of patients die due to disease recurrence and most survivors suffer from long-term side effects. MB is clinically, genetically, and epigenetically heterogeneous and subdivided into at least four molecular subgroups: WNT, SHH, Group 3, and Group 4. We evaluated common differentially expressed genes between a Brazilian RNA-seq GSE181293 dataset and microarray GSE85217 dataset cohort of pediatric MB samples using bioinformatics methodology in order to identify hub genes of the molecular subgroups based on PPI network construction, survival and functional analysis. The main finding was the identification of five hub genes from the WNT subgroup that are tumor suppressors, and whose lower expression is related to a worse prognosis for MB patients. Furthermore, the common genes correlated with the five tumor suppressors participate in important pathways and processes for tumor initiation and progression, as well as development and differentiation, and some of them control cell stemness and pluripotency. These genes have not yet been studied within the context of MB, representing new important elements for investigation in the search for therapeutic targets, prognostic markers or for understanding of MB biology.


Subject(s)
Brain Neoplasms , Cerebellar Neoplasms , Medulloblastoma , Humans , Child , Medulloblastoma/genetics , Medulloblastoma/metabolism , Medulloblastoma/pathology , Prognosis , Cerebellar Neoplasms/genetics , Cerebellar Neoplasms/metabolism , Cerebellar Neoplasms/pathology , Gene Expression Profiling , Biomarkers, Tumor/genetics
2.
Int J Mol Sci ; 24(11)2023 Jun 02.
Article in English | MEDLINE | ID: mdl-37298628

ABSTRACT

Increased glycolytic metabolism plays an important role in B-cell precursor Acute Lymphoblastic Leukemia (BCP-ALL). We previously showed that IGFBP7 exerts mitogenic and prosuvival effects in ALL by promoting IGF1 receptor (IGF1R) permanence on the cell surface, thus prolonging Akt activation upon IGFs/insulin stimulation. Here, we show that sustained activation of the IGF1R-PI3K-Akt axis concurs with GLUT1 upregulation, which enhances energy metabolism and increases glycolytic metabolism in BCP-ALL. IGFBP7 neutralization with a monoclonal antibody or the pharmacological inhibition of the PI3K-Akt pathway was shown to abrogate this effect, restoring the physiological levels of GLUT1 on the cell surface. The metabolic effect described here may offer an additional mechanistic explanation for the strong negative impact seen in ALL cells in vitro and in vivo after the knockdown or antibody neutralization of IGFBP7, while reinforcing the notion that it is a valid target for future therapeutic interventions.


Subject(s)
Insulin-Like Growth Factor Binding Proteins , Precursor B-Cell Lymphoblastic Leukemia-Lymphoma , Proto-Oncogene Proteins c-akt , Humans , Cell Line, Tumor , Cell Proliferation , Glucose Transporter Type 1/genetics , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Receptor, IGF Type 1/metabolism
3.
Blood ; 136(13): 1520-1534, 2020 09 24.
Article in English | MEDLINE | ID: mdl-32396934

ABSTRACT

High-risk B-cell acute lymphoblastic leukemia (B-ALL) is an aggressive disease, often characterized by resistance to chemotherapy. A frequent feature of high-risk B-ALL is loss of function of the IKAROS (encoded by the IKZF1 gene) tumor suppressor. Here, we report that IKAROS regulates expression of the BCL2L1 gene (encodes the BCL-XL protein) in human B-ALL. Gain-of-function and loss-of-function experiments demonstrate that IKAROS binds to the BCL2L1 promoter, recruits histone deacetylase HDAC1, and represses BCL2L1 expression via chromatin remodeling. In leukemia, IKAROS' function is impaired by oncogenic casein kinase II (CK2), which is overexpressed in B-ALL. Phosphorylation by CK2 reduces IKAROS binding and recruitment of HDAC1 to the BCL2L1 promoter. This results in a loss of IKAROS-mediated repression of BCL2L1 and increased expression of BCL-XL. Increased expression of BCL-XL and/or CK2, as well as reduced IKAROS expression, are associated with resistance to doxorubicin treatment. Molecular and pharmacological inhibition of CK2 with a specific inhibitor CX-4945, increases binding of IKAROS to the BCL2L1 promoter and enhances IKAROS-mediated repression of BCL2L1 in B-ALL. Treatment with CX-4945 increases sensitivity to doxorubicin in B-ALL, and reverses resistance to doxorubicin in multidrug-resistant B-ALL. Combination treatment with CX-4945 and doxorubicin show synergistic therapeutic effects in vitro and in preclinical models of high-risk B-ALL. Results reveal a novel signaling network that regulates chemoresistance in leukemia. These data lay the groundwork for clinical testing of a rationally designed, targeted therapy that combines the CK2 inhibitor, CX-4945, with doxorubicin for the treatment of hematopoietic malignancies.


Subject(s)
Casein Kinase II/genetics , Drug Resistance, Neoplasm , Gene Expression Regulation, Leukemic , Ikaros Transcription Factor/genetics , Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics , bcl-X Protein/genetics , Animals , Antibiotics, Antineoplastic/pharmacology , Antibiotics, Antineoplastic/therapeutic use , Cell Line, Tumor , Doxorubicin/pharmacology , Doxorubicin/therapeutic use , Gene Expression Regulation, Leukemic/drug effects , Humans , Mice , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy
4.
Pediatr Blood Cancer ; 69(7): e29553, 2022 07.
Article in English | MEDLINE | ID: mdl-34971073

ABSTRACT

Pediatric adrenocortical tumors (ACT) are rare aggressive neoplasms with heterogeneous prognosis. Despite extensive efforts, identifying reliable prognostic factors for pediatric patients with ACT remains a challenge. MicroRNA (miRNA) signatures have been associated with cancer diagnosis, treatment response, and prognosis of several types of cancer. However, the role of miRNAs has been poorly explored in pediatric ACT. In this study, we performed miRNA microarray profiling on a cohort of 37 pediatric ACT and nine nonneoplastic adrenal (NNA) samples and evaluated the prognostic significance of abnormally expressed miRNAs using Kaplan-Meier plots, log-rank test, and Cox regression analysis. We identified a total of 98 abnormally expressed miRNAs; their expression profile discriminated ACT from NNAs. Among the 98 deregulated miRNAs, 17 presented significant associations with patients' survival. In addition, higher expression levels of hsa-miR-630, -139-3p, -125a-3p, -574-5p, -596, -564, -1321, and -423-5p and lower expression levels of hsa-miR-377-3p, -126-3p, -410, -136-3p, -29b-3p, -29a-3p, -337-5p, -143-3p, and 140-5p were significantly associated with poor prognosis, tumor relapse, and/or death. Importantly, the expression profile of these 17 miRNAs stratified patients into two groups of ACTs with different clinical outcomes. Although some individual miRNAs exhibit potential prognostic values in ACTs, only the 17 miRNA-based expression clustering was considered an independent prognostic factor for 5-year event-free survival (EFS) compared to other clinicopathological features. In conclusion, our study reports for the first time associations between miRNA profiles and childhood ACT prognosis, providing evidence that miRNAs could be useful biomarkers to discriminate patients with favorable and unfavorable clinical outcomes.


Subject(s)
Gene Expression Profiling , MicroRNAs , Biomarkers , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Child , Gene Expression Regulation, Neoplastic , Humans , MicroRNAs/genetics , MicroRNAs/metabolism , Prognosis
5.
Mol Biol Rep ; 47(9): 6949-6959, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32888124

ABSTRACT

Glioblastoma (GBM) is the most common primary malignant neoplasm of the central nervous system and, despite the standard therapy; the patients' prognoses remain dismal. The miRNA expression profiles have been associated with patient prognosis, suggesting that they may be helpful for tumor diagnosis and classification as well as predictive of tumor response to treatment. We described the microRNA expression profile of 29 primary GBM samples (9 pediatric GBMs) and 11 non-neoplastic white matter samples as controls (WM) by microarray analysis and we performed functional in vitro assays on these 2 most differentially expressed miRNAs. Hierarchical clustering analysis showed 3 distinct miRNA profiles, two of them in the GBM samples and a group consisting only of cerebral white matter. When adult and pediatric GBMs were compared to WM, 37 human miRNAs were found to be differentially expressed, with miR-10b-5p being the most overexpressed and miR-630 the most underexpressed. The overexpression of miR-630 was associated with reduced cell proliferation and invasion in the U87 GBM cell line, whereas the inhibition of miR-10b-5p reduced cell proliferation and colony formation in the U251 GBM cell line, suggesting that these miRNAs may act as tumor-suppressive and oncogenic miRNAs, respectively. The present study highlights the distinct epigenetic profiling of adult and pediatric GBMs and underscores the biological importance of mir-10b-5p and miR-630 for the pathobiology of these lethal tumors.


Subject(s)
Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Glioblastoma/metabolism , MicroRNAs/biosynthesis , RNA, Neoplasm/biosynthesis , Adolescent , Adult , Aged , Cell Line, Tumor , Child , Child, Preschool , Female , Glioblastoma/pathology , Humans , Male , Middle Aged
6.
Neurol Sci ; 41(3): 691-694, 2020 Mar.
Article in English | MEDLINE | ID: mdl-31728854

ABSTRACT

BACKGROUND: Ependymoma (EPN) is the third most common childhood cancer of the central nervous system. RELA fusion-positive EPN accounts for approximately 70% of all childhood supratentorial tumors and shows the worst prognosis among the supratentorial EPNs. TP53 mutation is infrequent in RELA fusions EPNs. In the population from the Southern region of Brazil, there is a high incidence of the germline TP53 p.R337H mutation that predisposes carriers to develop early-onset tumors. However, despite this high incidence, the frequency of this mutation among EPN patients remains to be determined. Here, we investigated the presence of the TP53 p.R337H mutation in a larger cohort of pediatric EPNs of three institutions located in the state of São Paulo, Brazil. METHODS: The TP53 p.R337H mutation was screened by conventional RT-PCR and Sanger sequencing in 49 pediatric EPNs diagnosed during the period from 1995 to 2016. RESULTS: We described for the first time a case of a 5-year-old girl with RELA fusion EPN with a heterozygous TP53 p.R337H mutation. CONCLUSIONS: The present finding indicates that the TP53 p.R337H germline mutation is uncommon in patients with EPN in Brazil and screening of pediatric patients RELA fusion EPN may be informative to better understand the role of TP53 germline mutations in the development and prognosis of these tumors.


Subject(s)
Ependymoma/genetics , Supratentorial Neoplasms/genetics , Tumor Suppressor Protein p53/genetics , Brazil/epidemiology , Child , Child, Preschool , Cohort Studies , Ependymoma/epidemiology , Female , Germ-Line Mutation , Humans , Male , Supratentorial Neoplasms/epidemiology , Transcription Factor RelA
7.
J Cell Mol Med ; 23(2): 1562-1571, 2019 02.
Article in English | MEDLINE | ID: mdl-30484958

ABSTRACT

The role of tumour microenvironment in neoplasm initiation and malignant evolution has been increasingly recognized. However, the bone marrow mesenchymal stromal cell (BMMSC) contribution to disease progression remains poorly explored. We previously reported that the expression of serine protease inhibitor kunitz-type2 (SPINT2/HAI-2), an inhibitor of hepatocyte growth factor (HGF) activation, is significantly lower in BMMSC from myelodysplastic syndromes (MDS) patients compared to healthy donors (HD). Thus, to investigate whether this loss of expression was due to SPINT2/HAI-2 methylation, BMMSC from MDS and de novo acute myeloid leukaemia (de novo AML) patients were treated with 5-Azacitidine (Aza), a DNA methyltransferase inhibitor. In MDS- and de novo AML-BMMSC, Aza treatment resulted in a pronounced SPINT2/HAI-2 levels up-regulation. Moreover, Aza treatment of HD-BMMSC did not improve SPINT2/HAI-2 levels. To understand the role of SPINT2/HAI-2 down-regulation in BMMSC physiology, SPINT2/HAI-2 expression was inhibited by lentivirus. SPINT2 underexpression resulted in an increased production of HGF by HS-5 stromal cells and improved survival of CD34+ de novo AML cells. We also observed an increased adhesion of de novo AML hematopoietic cells to SPINT2/HAI-2 silenced cells. Interestingly, BMMSC isolated from MDS and de novo AML patients had increased expression of the integrins CD49b, CD49d, and CD49e. Thus, SPINT2/HAI-2 may contribute to functional and morphological abnormalities of the microenvironment niche and to stem/progenitor cancer cell progression. Hence, down-regulation in SPINT2/HAI-2 gene expression, due to methylation in MDS-BMMSC and de novo AML-BMMSC, provides novel insights into the pathogenic role of the leukemic bone marrow microenvironment.


Subject(s)
Azacitidine/pharmacology , Leukemia, Myeloid, Acute/drug therapy , Membrane Glycoproteins/genetics , Myelodysplastic Syndromes/drug therapy , Cell Adhesion/drug effects , Cell Line, Tumor , Cell Survival/drug effects , Female , Humans , Integrin alpha2/genetics , Leukemia, Myeloid, Acute/genetics , Leukemia, Myeloid, Acute/pathology , Male , Mesenchymal Stem Cells/drug effects , Middle Aged , Myelodysplastic Syndromes/genetics , Myelodysplastic Syndromes/pathology , Neoplastic Stem Cells/drug effects , Tumor Microenvironment/drug effects
8.
J Neurooncol ; 141(2): 373-382, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30570705

ABSTRACT

PURPOSES: Pilocytic astrocytoma (PA) is a low-grade neoplasm frequently found in childhood. PA is characterized by slow growth and a relatively good prognosis. Genetic mechanisms such as activation of MAPK, BRAF gene deregulation and neurofibromatosis type 1 (NF1) syndrome have been associated with PA development. Epigenetic signature and miRNA expression profile are providing new insights about different types of tumor, including PAs. METHODS: In the present study we evaluated global miRNA expression in 16 microdissected pediatric PA specimens, three NF1-associated PAs and 11 cerebral white matter (WM) samples by the microarray method. An additional cohort of 20 PAs was used to validate by qRT-PCR the expression of six miRNAs differentially expressed in the microarray data. RESULTS: Unsupervised hierarchical clustering analysis distinguished one cluster with nine PAs, including all NF1 cases and a second group consisting of the WM samples and seven PAs. Among 88 differentially expressed miRNAs between PAs and WM samples, the most underexpressed ones regulate classical pathways of tumorigenesis, while the most overexpressed miRNAs are related to pathways such as focal adhesion, P53 signaling pathway and gliomagenesis. The PAs/NF1 presented a subset of underexpressed miRNAs, which was also associated with known deregulated pathways in cancer such as cell cycle and hippo pathway. CONCLUSIONS: In summary, our data demonstrate that PA harbors at least two distinct miRNA signatures, including a subgroup of patients with NF1/PA lesions.


Subject(s)
Astrocytoma/metabolism , Brain Neoplasms/metabolism , Gene Expression Regulation, Neoplastic , MicroRNAs/metabolism , White Matter/metabolism , Adolescent , Astrocytoma/genetics , Brain Neoplasms/genetics , Child , Child, Preschool , Cluster Analysis , Female , Gene Expression Profiling , Humans , Infant , Male , Neurofibromatosis 1/genetics
9.
J Neurooncol ; 139(1): 33-42, 2018 Aug.
Article in English | MEDLINE | ID: mdl-29582271

ABSTRACT

INTRODUCTION: Medulloblastoma (MB) is an embryonal tumour that originates from genetic deregulation of cerebellar developmental pathways and is classified into 4 molecular subgroups: SHH, WNT, group 3, and group 4. Hydroxymethylation levels progressively increases during cerebellum development suggesting a possibility of deregulation in MB pathogenesis. The aim of this study was to investigate global hydroxymethylation levels and changes in TET and IDH gene expression in MB samples compared to control cerebellum samples. METHODS: The methods utilized were qRT-PCR for gene expression, dot-blot and immunohistochemistry for global hydroxymethylation levels and sequencing for the investigation of IDH mutations. RESULTS: Our results show that global hydroxymethylation level was decreased in MB, and low 5hmC level was associated with the presence of metastasis. TET1 expression levels were decreased in the WNT subgroup, while TET3 expression levels were decreased in the SHH subgroup. Reduced TET3 expression levels were associated with the presence of events such as relapse and death. Higher expression of IDH1 was observed in MB group 3 samples, whereas no mutations were detected in exon 4 of IDH1 and IDH2. CONCLUSION: These findings suggest that reduction of global hydroxymethylation levels, an epigenetic event, may be important for MB development and/or maintenance, representing a possible target in this tumour and indicating a possible interaction of TET and IDH genes with the developmental pathways specifically activated in the MB subgroups. These genes could be specific targets and markers for each subgroup.


Subject(s)
Cerebellar Neoplasms/metabolism , DNA Methylation , Isocitrate Dehydrogenase/metabolism , Medulloblastoma/metabolism , Proto-Oncogene Proteins/metabolism , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Cerebellar Neoplasms/genetics , Cerebellum/metabolism , Child , Child, Preschool , Female , Gene Expression Regulation, Neoplastic , Humans , Isocitrate Dehydrogenase/genetics , Male , Medulloblastoma/genetics , Mutation , Proto-Oncogene Proteins/genetics
10.
J Nanosci Nanotechnol ; 18(5): 3722-3728, 2018 May 01.
Article in English | MEDLINE | ID: mdl-29442890

ABSTRACT

Titanium dioxide (TiO2) has attracted attention as a photosensitizer in the field of photodynamic therapy (PDT) due to its low toxicity and high photostability. In the present work, nitrogen-doped TiO2 (N-TiO2) nanoparticles had their photokilling efficiency evaluated on a murine melanoma cell line (B16-F10) and fibroblasts (NIH 3T3). The N-TiO2 nanoparticles were prepared by a modified hydrogen peroxide sol-gel process using triethylamine as nitrogen precursor. XRD measurements showed that all TiO2 and N-TiO2 samples consisted of an anatase crystalline phase and no trace of rutile was detected. N-TiO2 nanoparticles showed higher absorbance in the visible region than pure TiO2. Nanoparticle dosage increase from 0.1 mg/ml to 0.5 mg/ml played a role in cell viability, causing high cytotoxicity in melanoma and fibroblast cells. The cytotoxic potential of N-TiO2 on cells was analyzed using visible light, UV-A irradiation and dark conditions. All samples were cytotoxic in a PDT test, and N-TiO2 caused 93% death in melanoma cells under UV irradiation treatment at 0.5 mg/ml. Gene expression analysis of this sample showed, under ultraviolet photoexcitation, an increase of pro-apoptotic BAX gene expression, suggesting cell death by apoptosis.


Subject(s)
Melanoma/drug therapy , Nanoparticles/therapeutic use , Skin Neoplasms/drug therapy , Titanium/therapeutic use , Animals , Catalysis , Light , Mice , Nitrogen
11.
Invest New Drugs ; 35(1): 26-36, 2017 02.
Article in English | MEDLINE | ID: mdl-27785591

ABSTRACT

Medulloblastoma (MB) is the most common solid tumor among pediatric patients and corresponds to 20 % of all pediatric intracranial tumors in this age group. Its treatment currently involves significant side effects. Epigenetic changes such as DNA methylation may contribute to its development and progression. DNA methyltransferase (DNMT) inhibitors have shown promising anticancer effects. The agent Zebularine acts as an inhibitor of DNA methylation and shows low toxicity and high efficacy, being a promising adjuvant agent for anti-cancer chemotherapy. Several studies have reported its effects on different types of tumors; however, there are no studies reporting its effects on MB. We analyzed its potential anticancer effects in four pediatric MB cell lines. The treatment inhibited proliferation and clonogenicity, increased the apoptosis rate and the number of cells in the S phase (p < 0.05), as well as the expression of p53, p21, and Bax, and decreased cyclin A, Survivin and Bcl-2 proteins. In addition, the combination of zebularine with the chemotherapeutic agents vincristine and cisplatin resulted in synergism and antagonism, respectively. Zebularine also modulated the activation of the SHH pathway, reducing SMO and GLI1 levels and one of its targets, PTCH1, without changing SUFU levels. A microarray analysis revealed different pathways modulated by the drug, including the Toll-Like Receptor pathway and high levels of the BATF2 gene. The low expression of this gene was associated with a worse prognosis in MB. Taken together, these data suggest that Zebularine may be a potential drug for further in vivo studies of MB treatment.


Subject(s)
Antineoplastic Agents/pharmacology , Basic-Leucine Zipper Transcription Factors/genetics , Cerebellar Neoplasms/drug therapy , Cytidine/analogs & derivatives , DNA Modification Methylases/antagonists & inhibitors , Medulloblastoma/drug therapy , Tumor Suppressor Proteins/genetics , Adolescent , Adult , Apoptosis/drug effects , Biomarkers , Cell Cycle Proteins/metabolism , Cell Line, Tumor , Cerebellar Neoplasms/genetics , Cerebellar Neoplasms/metabolism , Child , Child, Preschool , Cisplatin/pharmacology , Cytidine/pharmacology , DNA Modification Methylases/metabolism , Drug Interactions , Female , Gene Expression Regulation, Neoplastic , Humans , Infant , Infant, Newborn , Male , Medulloblastoma/genetics , Medulloblastoma/metabolism , Oligonucleotide Array Sequence Analysis , Prognosis , Vincristine/pharmacology , Young Adult
12.
BMC Cancer ; 17(1): 756, 2017 Nov 13.
Article in English | MEDLINE | ID: mdl-29132324

ABSTRACT

BACKGROUND: The spontaneous immortalization of primary malignant cells is frequently assigned to their genetic instability during in vitro culturing. In this study, the new epithelial ovarian cancer cell line CAISMOV24 was described and compared with its original low-grade serous ovarian carcinoma. METHODS: The in vitro culture was established with cells isolated from ascites of a 60-year-old female patient with recurrent ovarian cancer. The CAISMOV24 line was assessed for cell growth, production of soluble biomarkers, expression of surface molecules and screened for typical mutations found in serous ovarian carcinoma. Additionally, comparative genomic hybridization was employed to compare genomic alterations between the CAISMOV24 cell line and its primary malignant cells. RESULTS: CAISMOV24 has been in continuous culture for more than 30 months and more than 100 in vitro passages. The cell surface molecules EpCAM, PVR and CD73 are overexpressed on CAISMOV24 cells compared to the primary malignant cells. CAISMOV24 continues to produce CA125 and HE4 in vitro. Although the cell line had developed alongside the accumulation of genomic alterations (28 CNV in primary cells and 37 CNV in CAISMOV24), most of them were related to CNVs already present in primary malignant cells. CAISMOV24 cell line harbored KRAS mutation with wild type TP53, therefore it is characterized as low-grade serous carcinoma. CONCLUSION: Our results corroborate with the idea that genomic alterations, depicted by CNVs, can be used for subtyping epithelial ovarian carcinomas. Additionally, CAISMOV24 cell line was characterized as a low-grade serous ovarian carcinoma, which still resembles its primary malignant cells.


Subject(s)
Cystadenocarcinoma, Serous/pathology , Ovarian Neoplasms/pathology , Biomarkers, Tumor , Cell Line, Tumor , Cell Proliferation , Cell Transformation, Neoplastic/genetics , Comparative Genomic Hybridization , Cystadenocarcinoma, Serous/genetics , Cystadenocarcinoma, Serous/metabolism , Cytogenetic Analysis , Female , Humans , Immunohistochemistry , Immunophenotyping , Middle Aged , Mutation , Neoplasm Grading , Ovarian Neoplasms/genetics , Ovarian Neoplasms/metabolism , Tumor Cells, Cultured
13.
Proc Natl Acad Sci U S A ; 111(51): E5564-73, 2014 Dec 23.
Article in English | MEDLINE | ID: mdl-25512523

ABSTRACT

Osteosarcoma is the most common primary bone tumor, yet there have been no substantial advances in treatment or survival in three decades. We examined 59 tumor/normal pairs by whole-exome, whole-genome, and RNA-sequencing. Only the TP53 gene was mutated at significant frequency across all samples. The mean nonsilent somatic mutation rate was 1.2 mutations per megabase, and there was a median of 230 somatic rearrangements per tumor. Complex chains of rearrangements and localized hypermutation were detected in almost all cases. Given the intertumor heterogeneity, the extent of genomic instability, and the difficulty in acquiring a large sample size in a rare tumor, we used several methods to identify genomic events contributing to osteosarcoma survival. Pathway analysis, a heuristic analytic algorithm, a comparative oncology approach, and an shRNA screen converged on the phosphatidylinositol 3-kinase/mammalian target of rapamycin (PI3K/mTOR) pathway as a central vulnerability for therapeutic exploitation in osteosarcoma. Osteosarcoma cell lines are responsive to pharmacologic and genetic inhibition of the PI3K/mTOR pathway both in vitro and in vivo.


Subject(s)
Bone Neoplasms/metabolism , Genome, Human , Osteosarcoma/metabolism , Phosphatidylinositol 3-Kinases/metabolism , TOR Serine-Threonine Kinases/metabolism , Bone Neoplasms/genetics , Bone Neoplasms/pathology , Cell Line, Tumor , Cell Proliferation , Genetic Heterogeneity , Germ-Line Mutation , Humans , Osteosarcoma/genetics , Osteosarcoma/pathology , Tumor Suppressor Protein p53/genetics
14.
Biochem Biophys Res Commun ; 474(4): 696-701, 2016 Jun 10.
Article in English | MEDLINE | ID: mdl-27154221

ABSTRACT

Plant aldo-keto reductases of the AKR4C subfamily play key roles during stress and are attractive targets for developing stress-tolerant crops. However, these AKR4Cs show little to no activity with previously-envisioned sugar substrates. We hypothesized a structural basis for the distinctive cofactor binding and substrate specificity of these plant enzymes. To test this, we solved the crystal structure of a novel AKR4C subfamily member, the AKR4C7 from maize, in the apo form and in complex with NADP(+). The binary complex revealed an intermediate state of cofactor binding that preceded closure of Loop B, and also indicated that conformational changes upon substrate binding are required to induce a catalytically-favorable conformation of the active-site pocket. Comparative structural analyses of homologues (AKR1B1, AKR4C8 and AKR4C9) showed that evolutionary redesign of plant AKR4Cs weakened interactions that stabilize the closed conformation of Loop B. This in turn decreased cofactor affinity and altered configuration of the substrate-binding site. We propose that these structural modifications contribute to impairment of sugar reductase activity in favor of other substrates in the plant AKR4C subgroup, and that catalysis involves a three-step process relevant to other AKRs.


Subject(s)
Aldehyde Reductase/chemistry , Aldehyde Reductase/ultrastructure , NADP/chemistry , NADP/ultrastructure , Plant Proteins/chemistry , Plant Proteins/ultrastructure , Aldo-Keto Reductases , Binding Sites , Coenzymes/chemistry , Coenzymes/ultrastructure , Enzyme Activation , Molecular Docking Simulation , Protein Binding , Protein Conformation , Substrate Specificity
17.
Br J Haematol ; 171(5): 736-51, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26456771

ABSTRACT

Lymphotoxin-mediated activation of the lymphotoxin-ß receptor (LTßR; LTBR) has been implicated in cancer, but its role in T-cell acute lymphoblastic leukaemia (T-ALL) has remained elusive. Here we show that the genes encoding lymphotoxin (LT)-α and LTß (LTA, LTB) are expressed in T-ALL patient samples, mostly of the TAL/LMO molecular subtype, and in the TEL-JAK2 transgenic mouse model of cortical/mature T-ALL (Lta, Ltb). In these mice, expression of Lta and Ltb is elevated in early stage T-ALL. Surface LTα1 ß2 protein is expressed in primary mouse T-ALL cells, but only in the absence of microenvironmental LTßR interaction. Indeed, surface LT expression is suppressed in leukaemic cells contacting Ltbr-expressing but not Ltbr-deficient stromal cells, both in vitro and in vivo, thus indicating that dynamic surface LT expression in leukaemic cells depends on interaction with its receptor. Supporting the notion that LT signalling plays a role in T-ALL, inactivation of Ltbr results in a significant delay in TEL-JAK2-induced leukaemia onset. Moreover, young asymptomatic TEL-JAK2;Ltbr(-/-) mice present markedly less leukaemic thymocytes than age-matched TEL-JAK2;Ltbr(+/+) mice and interference with LTßR function at this early stage delayed T-ALL development. We conclude that LT expression by T-ALL cells activates LTßR signalling in thymic stromal cells, thus promoting leukaemogenesis.


Subject(s)
Lymphotoxin beta Receptor/physiology , Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/genetics , Animals , Carcinogenesis/genetics , Cell Line, Tumor , Cell Lineage/genetics , Gene Expression/genetics , Humans , Immunophenotyping , Janus Kinase 2/genetics , Lymphotoxin beta Receptor/genetics , Lymphotoxin beta Receptor/metabolism , Mice, Knockout , Mice, Transgenic , Molecular Sequence Data , Signal Transduction , Tumor Microenvironment/genetics
18.
Pediatr Hematol Oncol ; 32(5): 322-30, 2015.
Article in English | MEDLINE | ID: mdl-26086683

ABSTRACT

OBJECTIVE: to investigate the associations of oral microbiota, leucocytes count, neutrophil count, platelet counts and hemoglobin level, and the severity of oral mucositis in pediatric patients with acute lymphoblastic leukemia (ALL) receiving chemotherapy. MATERIALS AND METHODS: 71 prospective patients were included. Analyses of oral microbiota and blood sample were conducted on days 14 (D14) and 56 (D56) of the Brazilian GBTLI-99 treatment protocol. Herpes simplex virus (HSV) identification was performed by PCR followed by DNA sequencing analysis. Bacteria and fungi identification was obtained by standard microbiological culture tests. RESULTS: 103 episodes of mucositis occurred, being 65 at D14 and 38 at D56. Most cases positive for herpes viral DNA sequences were identified as HSV-1. At D14, we found a significant association between the severity of mucositis and presence of HSV-1 (p = 0.0347), Candida spp. (p = 0.0078), and low platelet count (p = 0.0064). At D56, we found a significant association between the severity of mucositis and the presence of HSV-1 (p = 0.0317), previous HSV-1 presence on D14 (p < 0.0001) and neutrophil count (p = 0.0211). CLINICAL RELEVANCE: the identification of risk factors for mucositis in children and adolescents may contribute to the development of new strategies for prevention and/or treatment, reducing the complications associated with this condition. CONCLUSIONS: the presence of HSV, platelet count, and Candida spp. presence at D14 of ALL induction treatment is associated with increased severity of mucositis in children and adolescents. At D56 of ALL treatment, mucositis severity was associated with neutrophil count, HSV presence, and previous presence of HSV (at D14).


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/adverse effects , Candida , Candidiasis/epidemiology , Herpes Simplex/epidemiology , Herpesvirus 1, Human , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Stomatitis/epidemiology , Adolescent , Adult , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Brazil/epidemiology , Candidiasis/chemically induced , Child , Child, Preschool , Female , Herpes Simplex/chemically induced , Humans , Infant , Male , Precursor Cell Lymphoblastic Leukemia-Lymphoma/epidemiology , Prospective Studies , Stomatitis/chemically induced
20.
Cancers (Basel) ; 16(6)2024 Mar 08.
Article in English | MEDLINE | ID: mdl-38539429

ABSTRACT

Pediatric adrenocortical tumors (ACTs) are rare, highly heterogeneous neoplasms with limited therapeutic options, making the investigation of new targets with potential therapeutic or prognostic purposes urgent. The PRKAB2 gene produces one of the subunits of the AMP-activated protein kinase (AMPK) complex and has been associated with cancer. However, little is known about the role AMPK plays in ACTs. We have evaluated how PRKAB2 is associated with clinical and biological characteristics in 63 pediatric patients with ACTs and conducted in vitro studies on the human NCI-H295R ACC cell line. An analysis of our cohort and the public ACC pediatric dataset GSE76019 showed that lower PRKAB2 expression was associated with relapse, death, metastasis, and lower event-free and overall survival rates. Multivariate analysis showed that PRKAB2 expression was an independent prognostic factor when associated with age, tumor weight and volume, and metastasis. In vitro tests on NCI-H295R cells demonstrated that Rottlerin, a drug that can activate AMPK, modulated several pathways in NCI-H295R cells, including AMPK/mTOR, Wnt/ß-catenin, SKP2, HH, MAPK, NFKB, and TNF. Treatment with Rottlerin decreased cell proliferation and migration, clonogenic capacity, and steroid production. Together, these results suggest that PRKAB2 is a potential prognostic marker in pediatric ACTs, and that Rottlerin is promising for investigating drugs that can act against ACTs.

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