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1.
Clin Transl Med ; 11(11): e592, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34841698

RESUMO

BACKGROUND: The key role of hypoxia-inducible factor 2alpha (HIF2α) in the process of renal cancer has been confirmed. In the field of tumour research, oxidative stress is also considered to be an important influencing factor. However, the relationship and biological benefits of oxidative stress and HIF2α in ccRCC remain unclear. This research attempts to explore the effect of oxidative stress on the cancer-promoting effect of HIF2α in ccRCC and reveal its mechanism of action. METHODS: The bioinformatics analysis for ccRCC is based on whole transcriptome sequencing and TCGA database. The detection of the expression level of related molecules is realised by western blot and PCR. The expression of Nucleoside diphosphate-linked moiety X-type motif 1 (NUDT1) was knocked down by lentiviral infection technology. The functional role of NUDT1 were further investigated by CCK8 assays, transwell assays and cell oxidative stress indicator detection. The exploration of related molecular mechanisms is realised by Luciferase assays and Chromatin immunoprecipitation (ChIP) assays. RESULTS: Molecular screening based on knockdown HIF2α sequencing data and oxidative stress related data sets showed that NUDT1 is considered to be an important molecule for the interaction of HIF2α with oxidative stress. Subsequent experimental results showed that NUDT1 can cooperate with HIF2α to promote the progression of ccRCC. And this biological effect was found to be caused by the oxidative stress regulated by NUDT1. Mechanistically, HIF2α transcription activates the expression of NUDT1, thereby inhibiting oxidative stress and promoting the progression of ccRCC. CONCLUSIONS: This research clarified a novel mechanism by which HIF2α stabilises sirtuin 3 (SIRT3) through direct transcriptional activation of NUDT1, thereby inhibiting oxidative stress to promote the development of ccRCC. It provided the possibility for the selection of new therapeutic targets for ccRCC and the study of combination medication regimens.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/efeitos adversos , Carcinoma de Células Renais/genética , Enzimas Reparadoras do DNA/efeitos dos fármacos , Estresse Oxidativo/genética , Monoéster Fosfórico Hidrolases/efeitos dos fármacos , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Carcinoma de Células Renais/fisiopatologia , Linhagem Celular Tumoral/metabolismo , Enzimas Reparadoras do DNA/genética , Humanos , Neoplasias , Estresse Oxidativo/efeitos dos fármacos , Monoéster Fosfórico Hidrolases/genética
2.
BMC Cancer ; 21(1): 493, 2021 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-33941107

RESUMO

BACKGROUND: Glioblastoma (GBM) is the deadliest and the most common primary brain tumor in adults. The invasiveness and proliferation of GBM cells can be decreased through the inhibition of Wnt/ß-catenin pathway. In this regard, celecoxib is a promising agent, but other COXIBs and 2,5-dimethylcelecoxib (2,5-DMC) await elucidation. Thus, the aim of this study was to analyze the impact of celecoxib, 2,5-DMC, etori-, rofe-, and valdecoxib on GBM cell viability and the activity of Wnt/ß-catenin pathway. In addition, the combination of the compounds with temozolomide (TMZ) was also evaluated. Cell cycle distribution and apoptosis, MGMT methylation level, COX-2 and PGE2 EP4 protein levels were also determined in order to better understand the molecular mechanisms exerted by these compounds and to find out which of them can serve best in GBM therapy. METHODS: Celecoxib, 2,5-DMC, etori-, rofe- and valdecoxib were evaluated using three commercially available and two patient-derived GBM cell lines. Cell viability was analyzed using MTT assay, whereas alterations in MGMT methylation level were determined using MS-HRM method. The impact of COXIBs, in the presence and absence of TMZ, on Wnt pathway was measured on the basis of the expression of ß-catenin target genes. Cell cycle distribution and apoptosis analysis were performed using flow cytometry. COX-2 and PGE2 EP4 receptor expression were evaluated using Western blot analysis. RESULTS: Wnt/ß-catenin pathway was attenuated by COXIBs and 2,5-DMC irrespective of the COX-2 expression profile of the treated cells, their MGMT methylation status, or radio/chemoresistance. Celecoxib and 2,5-DMC were the most cytotoxic. Cell cycle distribution was altered, and apoptosis was induced after the treatment with celecoxib, 2,5-DMC, etori- and valdecoxib in T98G cell line. COXIBs and 2,5-DMC did not influence MGMT methylation status, but inhibited COX-2/PGE2/EP4 pathway. CONCLUSIONS: Not only celecoxib, but also 2,5-DMC, etori-, rofe- and valdecoxib should be further investigated as potential good anti-GBM therapeutics.


Assuntos
Neoplasias Encefálicas/metabolismo , Inibidores de Ciclo-Oxigenase 2/farmacologia , Glioblastoma/metabolismo , Proteínas de Neoplasias/efeitos dos fármacos , Pirazóis/farmacologia , Sulfonamidas/farmacologia , Via de Sinalização Wnt/efeitos dos fármacos , Idoso , Antineoplásicos Alquilantes/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias Encefálicas/tratamento farmacológico , Celecoxib/farmacologia , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Ciclo-Oxigenase 2/metabolismo , Metilases de Modificação do DNA/efeitos dos fármacos , Metilases de Modificação do DNA/metabolismo , Enzimas Reparadoras do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/metabolismo , Dinoprostona/metabolismo , Relação Dose-Resposta a Droga , Etoricoxib/farmacologia , Feminino , Glioblastoma/tratamento farmacológico , Humanos , Isoxazóis/farmacologia , Lactonas/farmacologia , Masculino , Metilação , Pessoa de Meia-Idade , Proteínas de Neoplasias/metabolismo , Receptores de Prostaglandina E Subtipo EP4/efeitos dos fármacos , Receptores de Prostaglandina E Subtipo EP4/metabolismo , Sulfonas/farmacologia , Temozolomida/farmacologia , Proteínas Supressoras de Tumor/efeitos dos fármacos , Proteínas Supressoras de Tumor/metabolismo , beta Catenina/efeitos dos fármacos , beta Catenina/metabolismo
3.
Clin Epigenetics ; 13(1): 35, 2021 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-33588926

RESUMO

BACKGROUND: Epigenetic inactivation of O6-methylguanine DNA-methyltransferase (MGMT) is associated with increased sensitivity to alkylating chemotherapeutic agents in glioblastoma patients. The genetic background underlying MGMT gene methylation may explain individual differences in treatment response and provide a clue to a personalized treatment strategy. Making use of the longitudinal twin design, we aimed, for the first time, to estimate the genetic contributions to MGMT methylation in a Danish twin cohort. METHODS: DNA-methylation from whole blood (18 monozygotic (MZ) and 25 dizygotic (DZ) twin pairs) repeated 10 years apart from the Longitudinal Study of Aging Danish Twins (LSADT) were used to search for genetic and environmental contributions to DNA-methylation at 170 CpG sites of across the MGMT gene. Both univariate and bivariate twin models were applied. The intraclass correlations, performed on cross-sectional data (246 MZ twin pairs) from an independent study population, the Middle-Aged Danish Twins (MADT), were used to assess the genetic influence at each CpG site of MGMT for replication. RESULTS: Univariate twin model revealed twelve CpG sites showing significantly high heritability at intake (wave 1, h2 > 0.43), and seven CpG sites with significant heritability estimates at end of follow-up (wave 2, h2 > 0.5). There were six significant CpG sites, located at the gene body region, that overlapped among the two waves (h2 > 0.5), of which five remained significant in the bivariate twin model, which was applied to both waves. Within MZ pair correlation in these six CpGs from MADT demarks top level of genetic influence. There were 11 CpGs constantly have substantial common environmental component over the 10 years. CONCLUSIONS: We have identified 6 CpG sites linked to the MGMT gene with strong and persistent genetic control based on their DNA methylation levels. The genetic basis of MGMT gene methylation could help to explain individual differences in glioblastoma treatment response and most importantly, provide references for mapping the methylation Quantitative Trait Loci (meQTL) underlying the genetic regulation.


Assuntos
Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , DNA/metabolismo , Glioblastoma/genética , Guanina/análogos & derivados , Proteínas Supressoras de Tumor/genética , Idoso , Envelhecimento/genética , Antineoplásicos Alquilantes/uso terapêutico , Estudos de Coortes , Ilhas de CpG/genética , Estudos Transversais , Metilação de DNA , Metilases de Modificação do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/efeitos dos fármacos , Dinamarca/epidemiologia , Meio Ambiente , Epigenômica , Feminino , Inativação Gênica/efeitos dos fármacos , Glioblastoma/tratamento farmacológico , Guanina/metabolismo , Humanos , Estudos Longitudinais , Masculino , Metiltransferases , Pessoa de Meia-Idade , Proteínas Supressoras de Tumor/efeitos dos fármacos , Gêmeos Dizigóticos/genética , Gêmeos Monozigóticos/genética
4.
CNS Neurosci Ther ; 27(5): 552-563, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33460245

RESUMO

BACKGROUND: Temozolomide (TMZ) is a first-line chemotherapy drug for the treatment of malignant glioma and resistance to it poses a major challenge. Receptor-interacting protein 2 (RIP2) is associated with the malignant character of cancer cells. However, it remains unclear whether RIP2 is involved in TMZ resistance in glioma. METHODS: RIP2 expression was inhibited in TMZ-resistant glioma cells and normal glioma cells by using small interfering RNA (siRNA) against RIP2. Plasmid transfection method was used to overexpress RIP2. Cell counting kit-8 assays were performed to evaluate cell viability. Western blotting or immunofluorescence was performed to determine RIP2, NF-κB, and MGMT expression in cells. Flow cytometry was used to investigate cell apoptosis. TMZ-resistant glioma xenograft models were established to evaluate the role of the RIP2/NF-κB/MGMT signaling pathway in drug resistance. RESULTS: We observed that RIP2 expression was upregulated in TMZ-resistant glioma cells, whereas silencing of RIP2 expression enhanced cellular sensitivity to TMZ. Similarly, upon the induction of RIP2 overexpression, glioma cells developed resistance to TMZ. The molecular mechanism underlying the process indicated that RIP2 can activate the NF-κB signaling pathway and upregulate the expression of O6-methylguanine-DNA methyltransferase (MGMT), following which the glioma cells develop drug resistance. In the TMZ-resistant glioma xenograft model, treatment with JSH-23 (an NF-κB inhibitor) and lomeguatrib (an MGMT inhibitor) could enhance the sensitivity of the transplanted tumor to TMZ. CONCLUSION: We report that the RIP2/NF-κB/MGMT signaling pathway is involved in the regulation of TMZ resistance. Interference with NF-κB or MGMT activity could constitute a novel strategy for the treatment of RIP2-positive TMZ-resistant glioma.


Assuntos
Antineoplásicos Alquilantes/farmacologia , Neoplasias Encefálicas/tratamento farmacológico , Metilases de Modificação do DNA/efeitos dos fármacos , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/genética , Resistencia a Medicamentos Antineoplásicos/genética , Glioma/tratamento farmacológico , NF-kappa B/efeitos dos fármacos , NF-kappa B/genética , Proteína Serina-Treonina Quinase 2 de Interação com Receptor/efeitos dos fármacos , Proteína Serina-Treonina Quinase 2 de Interação com Receptor/genética , Transdução de Sinais/efeitos dos fármacos , Temozolomida/farmacologia , Proteínas Supressoras de Tumor/efeitos dos fármacos , Proteínas Supressoras de Tumor/genética , Animais , Apoptose/efeitos dos fármacos , Neoplasias Encefálicas/genética , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glioma/genética , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , NF-kappa B/antagonistas & inibidores , RNA Interferente Pequeno/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto
5.
Asian Pac J Cancer Prev ; 21(10): 3099-3108, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33112573

RESUMO

PURPOSE: DNA damage is a continuous process occurring within the cells caused by intrinsic and extrinsic factors, but it gets repaired regularly. If the DNA repair process is faulty, the incidences of damages/mutations can accumulate in cells resulting in cell transformation. It is hypothesized that the negative variations in DNA repair pathways in even at one point viz. genetic, translational or posttranslational stage may fairly be crucial for the beginning and development of carcinogenesis. Therefore, we investigated the potential of tobacco specific nitrosamines (TSNs) related carcinogens to interact with the enzymes involved in DNA repair mechanisms in the current study. METHODS: The derivatives of cigarettes' smoke like NNK and NNAL are very well known and recognized carcinogens. Therefore, almost 120 enzymes playing crucial role in the DNA repair process have been analysed for their reactivity with NNK and NNAL. RESULTS: The molecular docking study helped to screen out,  07 possible DNA repair enzyme targets for NNK, and 12for NNAL. Present study revealed the loss of activity of DNA repair enzymes in the presence of NNK and NNAL, and this accumulation may induce the tendency of DNA damage which can lead the transformation of exposed normal cells in to cancerous cells. This study also demonstrated the protective potential of nanoparticles like SWCNTs/MWCNTs against TSN's induced toxicity; here SWCNT against NNK (-17.16 Kcal/Mol) and MWCNT against NNK -17.01 Kcal/Mol were showing maximum binding affinities than the known biomolecular target of NNK 1UGH (Uracil-DNA glycosylase,-7.82Kcal/Mol). CONCLUSION: CNTs can be applied as chemo-preventive agents against environmental and tobacco induced carcinogens owing to their scavenging potential and warrants for in vivo and in vitro experimental validation of the results obtained from the present study.
.


Assuntos
Carcinógenos/toxicidade , Enzimas Reparadoras do DNA/deficiência , Reparo do DNA , Nanotubos de Carbono/química , Produtos do Tabaco/efeitos adversos , Poluição por Fumaça de Tabaco/prevenção & controle , Dano ao DNA , Enzimas Reparadoras do DNA/química , Enzimas Reparadoras do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/metabolismo , Humanos , Domínios e Motivos de Interação entre Proteínas , Poluição por Fumaça de Tabaco/análise
6.
JCI Insight ; 5(12)2020 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-32554927

RESUMO

Oxidative stress and inadequate redox homeostasis is crucial for tumor initiation and progression. MTH1 (NUDT1) enzyme prevents incorporation of oxidized dNTPs by sanitizing the deoxynucleoside triphosphate (dNTP) pool and is therefore vital for the survival of tumor cells. MTH1 inhibition has been found to inhibit the growth of several experimental tumors, but its role in mesothelioma progression remained elusive. Moreover, although MTH1 is nonessential to normal cells, its role in survival of host cells in tumor milieu, especially tumor endothelium, is unclear. We validated a clinically relevant MTH1 inhibitor (Karonudib) in mesothelioma treatment using human xenografts and syngeneic murine models. We show that MTH1 inhibition impedes mesothelioma progression and that inherent tumoral MTH1 levels are associated with a tumor's response. We also identified tumor endothelial cells as selective targets of Karonudib and propose a model of intercellular signaling among tumor cells and bystander tumor endothelium. We finally determined the major biological processes associated with elevated MTH1 gene expression in human mesotheliomas.


Assuntos
Células Endoteliais/efeitos dos fármacos , Endotélio/efeitos dos fármacos , Mesotelioma/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , Monoéster Fosfórico Hidrolases/metabolismo , Pirimidinas/farmacologia , Animais , Linhagem Celular Tumoral , Enzimas Reparadoras do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/metabolismo , Células Endoteliais/metabolismo , Endotélio/metabolismo , Mesotelioma/metabolismo , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Nucleotídeos/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia
7.
World Neurosurg ; 116: e147-e161, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29709748

RESUMO

BACKGROUND: There is limited information on O6-methylguanine DNA methyltransferase (MGMT) status, extent of surgical resection, and its impact on overall outcomes in patients with glioblastoma (GBM). METHODS: After institutional review board approval, 233 newly diagnosed patients with GBM with known MGMT status (2009-2015) were included in our analysis. Clinical, imaging, and follow-up data were collected from the database. Overall survival (OS) and progression-free survival (PFS) were the primary and secondary end points, respectively. RESULTS: Of patients, 51.9% were younger than 65 years and 44.2% were noted to have promoter methylation of MGMT. Median residual tumor volume was 1.1 cm3 and extent of complete resection of enhancing tumor on imaging was 96%. Estimated median OS and PFS were 10.9 months and 5.4 months, respectively. MGMT status was an independent predictor of PFS (hazard ratio [HR], 0.52; P = 0.005) but only marginally associated with OS (P = 0.059). In MGMT methylated patients, extent of resection (≥86%) and good performance status (Karnofsky Performance Status ≥70) were independently associated with PFS and OS, respectively (PFS: HR, 0.21; P = 0.015; OS: HR, 0.05; P = 0.002). In MGMT promoter unmethylated patients, extent of resection (≥86%) was independently associated with OS (P = 0.039). Concurrent chemoradiotherapy was associated with OS/PFS irrespective of age and MGMT status. CONCLUSIONS: Greater extent of resection of enhancing tumor was associated with improved PFS in MGMT promoter methylated patients, OS regardless of MGMT status. Elderly patients with methylated MGMT promoter were found to have improved PFS whereas younger patients had improved OS with MGMT promoter methylated status.


Assuntos
Antineoplásicos Alquilantes/uso terapêutico , Glioblastoma/patologia , Guanina/análogos & derivados , Metiltransferases/metabolismo , Neoplasia Residual/patologia , Adulto , Idoso , Biomarcadores Tumorais/genética , Neoplasias Encefálicas/cirurgia , Metilases de Modificação do DNA/efeitos dos fármacos , Metilases de Modificação do DNA/metabolismo , Enzimas Reparadoras do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/metabolismo , Intervalo Livre de Doença , Feminino , Glioblastoma/genética , Glioblastoma/cirurgia , Guanina/farmacologia , Humanos , Masculino , Pessoa de Meia-Idade
8.
J Neurochem ; 144(2): 139-151, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29164620

RESUMO

Therapy of malignant glioma relies on treatment with the O6 -methylating agent temozolomide (TMZ) concomitant with ionizing radiation followed by adjuvant TMZ. For the treatment of recurrences, DNA chloroethylating drugs are also used. The main killing lesion induced by these drugs is O6 -alkylguanine. Since this damage is repaired by O6 -methylguanine-DNA methyltransferase (MGMT), the repair enzyme represents a most important factor of drug resistance, limiting the therapy of malignant high-grade gliomas. Although MGMT has been shown to be transcriptionally up-regulated in rodents following genotoxic stress, it is still unclear whether human MGMT is subject to up-regulation. Here, we addressed the question whether MGMT in glioma cells is enhanced following alkylating drugs or ionizing radiation, using promoter assays. We also checked the response of glioma cell lines to dexamethasone. In a series of experiments, we found no evidence that the human MGMT promoter is significantly up-regulated following treatment with TMZ, the chloroethylating agent nimustine or radiation. It was activated, however, by dexamethasone. Using deletion constructs, we further show that the basal level of MGMT is mainly determined by the transcription factor SP1. The high amount of SP1 sites in the MGMT promoter likely prevents transcriptional up-regulation following genotoxic stress by neutralizing inducible signals. The regulation of MGMT by miRNAs plays only a minor role, as shown by DICER knockdown experiments. Since high dose dexamethasone concomitant with temozolomide is frequently used in glioblastoma therapy, induction of the MGMT gene through glucocorticoids in MGMT promoter unmethylated cases might cause further elevation of drug resistance, while radiation and alkylating drugs seem not to induce MGMT at transcriptional level.


Assuntos
Antineoplásicos Alquilantes/farmacologia , Enzimas Reparadoras do DNA/genética , Glucocorticoides/farmacologia , O(6)-Metilguanina-DNA Metiltransferase/genética , Fator de Transcrição Sp1/genética , Temozolomida/farmacologia , Enzimas Reparadoras do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/efeitos da radiação , Dexametasona/farmacologia , Indução Enzimática/efeitos dos fármacos , Indução Enzimática/efeitos da radiação , Técnicas de Silenciamento de Genes , Humanos , O(6)-Metilguanina-DNA Metiltransferase/efeitos dos fármacos , O(6)-Metilguanina-DNA Metiltransferase/efeitos da radiação , Regiões Promotoras Genéticas/genética , RNA Mensageiro/farmacologia , Fator de Transcrição Sp1/efeitos dos fármacos , Fator de Transcrição Sp1/efeitos da radiação , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/efeitos da radiação
9.
J Med Chem ; 60(19): 8160-8169, 2017 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-28929756

RESUMO

Fragment-based lead discovery has emerged as a leading drug development strategy for novel therapeutic targets. Although fragment-based drug discovery benefits immensely from access to atomic-resolution information, structure-based virtual screening has rarely been used to drive fragment discovery and optimization. Here, molecular docking of 0.3 million fragments to a crystal structure of cancer target MTH1 was performed. Twenty-two predicted fragment ligands, for which analogs could be acquired commercially, were experimentally evaluated. Five fragments inhibited MTH1 with IC50 values ranging from 6 to 79 µM. Structure-based optimization guided by predicted binding modes and analogs from commercial chemical libraries yielded nanomolar inhibitors. Subsequently solved crystal structures confirmed binding modes predicted by docking for three scaffolds. Structure-guided exploration of commercial chemical space using molecular docking gives access to fragment libraries that are several orders of magnitude larger than those screened experimentally and can enable efficient optimization of hits to potent leads.


Assuntos
Descoberta de Drogas/métodos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Simulação por Computador , Cristalografia por Raios X , Enzimas Reparadoras do DNA/química , Enzimas Reparadoras do DNA/efeitos dos fármacos , Humanos , Ligantes , Modelos Moleculares , Simulação de Acoplamento Molecular , Monoéster Fosfórico Hidrolases/química , Monoéster Fosfórico Hidrolases/efeitos dos fármacos , Ligação Proteica , Bibliotecas de Moléculas Pequenas , Relação Estrutura-Atividade
10.
Mutagenesis ; 32(1): 161-172, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27803034

RESUMO

For some decades production of titanium dioxide nanoparticle (TiO2-NP) has been increasing at a considerable rate; concerns as to the toxicity of these particles upon inhalation have been raised. Indeed, TiO2-NPs have been shown to induce significant genotoxicity and to adversely affect both major DNA repair mechanisms: base excision repair (BER) and nucleotide excision repair (NER). The aims of the present study were to (i) compare the genotoxicity of TiO2-NPs and their impact on DNA repair processes on A549 alveolar carcinoma and BEAS-2B normal bronchial lung cell lines and (ii) delve deeper into the mechanisms leading to these effects. To achieve these goals, TiO2-NPs effects on cytotoxicity, genotoxicity, DNA repair activity and DNA repair gene expression were investigated in both cell lines upon exposure to 1-100 µg/mL of anatase/rutile, 21 nm TiO2-NPs. Our results show that TiO2-NPs induce comparable cytotoxic and genotoxic responses in BEAS-2B and A549 cells. Functional response to DNA damage is observed in both cell lines and consists of an overall downregulation in DNA repair processes. When evaluating the relative importance of the two DNA repair pathways, we observed a lower impact on BER compared with NER activities, suggesting that repair of oxidatively generated DNA damage is still triggered in these cells. This response becomes measureable at 4 h of exposure in BEAS-2B but only after 48 h of exposure in A549 cells. The delayed response in A549 cells is due to an initial overall and intense downregulation of the genes encoding DNA repair proteins. This overall downregulation correlates with increased methylation of DNA repair gene promoters and downregulation of NRF2 and BRCA1, which may thus be considered as upstream regulators. These results strengthen the evidence that TiO2-NP induces indirect genotoxicity in lung cells, via modulation of DNA repair processes, and shed some light on the mechanisms behind this effect.


Assuntos
Metilação de DNA , Enzimas Reparadoras do DNA/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Titânio/toxicidade , Células A549 , Linhagem Celular , DNA/efeitos dos fármacos , DNA/metabolismo , Dano ao DNA , Reparo do DNA/genética , Enzimas Reparadoras do DNA/genética , Regulação para Baixo , Humanos , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Nanopartículas Metálicas/química , Testes de Mutagenicidade , Estresse Oxidativo , Regiões Promotoras Genéticas
11.
Tumori ; 101(3): 257-62, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25953446

RESUMO

For many decades, lung cancer has been the most common cancer and the leading cause of cancer death worldwide. More than 50% of non-small-cell lung cancer patients receive radiotherapy (alone or in combination with chemotherapy or surgery) during their treatment. The intrinsic radiosensitivity of tumors and dose-limiting toxicity restrict the curative potential of radiotherapy. Histone deacetylase inhibitors (HDACis) are an emerging class of agents that target histone deacetylase and represent promising radiosensitizers that affect various biological processes, such as cell growth, apoptosis, DNA repair, and terminal differentiation. Histone deacetylase inhibitors have been found to suppress many important DNA damage responses by downregulating proteins in the homologous recombination and nonhomologous end joining repair pathways in vitro. In this review, we describe the rationale for using HDACis as radiosensitizers and the clinical evidence regarding the use of HDACis for the treatment of non-small-cell lung cancer.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/radioterapia , Enzimas Reparadoras do DNA/metabolismo , Proteínas de Ligação a DNA/metabolismo , Inibidores de Histona Desacetilases/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/radioterapia , Radiossensibilizantes/farmacologia , Fatores de Transcrição/metabolismo , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Benzamidas/farmacologia , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos da radiação , Ensaios Clínicos como Assunto , Reparo do DNA por Junção de Extremidades/efeitos dos fármacos , Reparo do DNA por Junção de Extremidades/efeitos da radiação , Enzimas Reparadoras do DNA/efeitos dos fármacos , DNA de Neoplasias/efeitos dos fármacos , DNA de Neoplasias/efeitos da radiação , Proteínas de Ligação a DNA/efeitos dos fármacos , Depsipeptídeos/farmacologia , Regulação para Baixo/efeitos dos fármacos , Inibidores de Histona Desacetilases/uso terapêutico , Humanos , Ácidos Hidroxâmicos/farmacologia , Indóis/farmacologia , Neoplasias Pulmonares/metabolismo , Panobinostat , Piridinas/farmacologia , Tolerância a Radiação/efeitos dos fármacos , Radiossensibilizantes/uso terapêutico , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/efeitos da radiação , Fatores de Transcrição/efeitos dos fármacos , Vorinostat
12.
Hum Pathol ; 45(10): 2029-36, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25150747

RESUMO

Immunohistochemistry (IHC) testing for mismatch repair proteins (MMRP) is currently being used primarily in colorectal cancer resection specimens. We aimed to compare the results of IHC staining performed on biopsy specimens obtained at endoscopy with that performed on surgical specimens after neoadjuvant therapy. Thirty-two rectal cancer subjects had paired preneoadjuvant and postneoadjuvant tissue available for IHC staining (MLH1, MSH2, MSH6, and PMS2), whereas 39 rectosigmoid cancer patients who did not receive neoadjuvant treatment served as controls. Each slide received a qualitative (absent, focal, and strong) and quantitative score (immunoreactivity [0-3] × percent positivity [0-4]). The quantitative scores of MMRP from the operative material were significantly lower in the neoadjuvant group than in the control (P < .05 for all).The scores of all MMRP from endoscopic biopsies were not significantly different between the neoadjuvant and the control groups. Disagreement between the endoscopic biopsy and the operative material was evident in 23 of 128 stains (18.5%) in the neoadjuvant group and in 12 of 156 stains (7.7%) in the control group (P = .009). In the neoadjuvant group, a disagreement pattern of "endoscopic strong operative focal" was observed in 28.1% for PMS2, 12.5% for MSH6, 12.5% for MLH1, and 6.3% for MSH2, and in the control group, this same disagreement pattern was found in 12.8% for PMS2, 7.7% for MSH6, 7.7% for MLH1, and 0% for MSH2. Based on our findings, we suggest that for rectal cancer, the endoscopic material rather than the operative material should serve as the primary material for IHC staining.


Assuntos
Neoplasias Colorretais/genética , Reparo de Erro de Pareamento de DNA , Imuno-Histoquímica/normas , Terapia Neoadjuvante , Proteínas de Neoplasias/análise , Proteínas Adaptadoras de Transdução de Sinal/análise , Proteínas Adaptadoras de Transdução de Sinal/efeitos dos fármacos , Proteínas Adaptadoras de Transdução de Sinal/efeitos da radiação , Adenosina Trifosfatases/análise , Adenosina Trifosfatases/efeitos dos fármacos , Adenosina Trifosfatases/efeitos da radiação , Idoso , Quimiorradioterapia , Neoplasias Colorretais/terapia , Enzimas Reparadoras do DNA/análise , Enzimas Reparadoras do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/efeitos da radiação , Proteínas de Ligação a DNA/análise , Proteínas de Ligação a DNA/efeitos dos fármacos , Proteínas de Ligação a DNA/efeitos da radiação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Endonuclease PMS2 de Reparo de Erro de Pareamento , Proteína 1 Homóloga a MutL , Proteína 2 Homóloga a MutS/análise , Proteína 2 Homóloga a MutS/efeitos dos fármacos , Proteína 2 Homóloga a MutS/efeitos da radiação , Proteínas de Neoplasias/efeitos dos fármacos , Proteínas de Neoplasias/efeitos da radiação , Proteínas Nucleares/análise , Proteínas Nucleares/efeitos dos fármacos , Proteínas Nucleares/efeitos da radiação , Reprodutibilidade dos Testes
13.
Neurochem Res ; 37(6): 1192-200, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22228201

RESUMO

Glioblastoma multiforme (GBM) is recognized as the most common and lethal form of central nervous system cancer. Currently used surgical techniques, chemotherapeutic agents, and radiotherapy strategies have done very little in extending the life expectancies of patients diagnosed with GBM. The difficulty in treating this malignant disease lies both in its inherent complexity and numerous mechanisms of drug resistance. In this review, we summarize several of the primary mechanisms of drug resistance. We reviewed available published literature in the English language regarding drug resistance in glioblastoma. The reasons for drug resistance in glioblastoma include drug efflux, hypoxic areas of tumor cells, cancer stem cells, DNA damage repair, and miRNAs. Many potential therapies target these mechanisms, including a series of investigated alternative and plant-derived agents. Future research and clinical trials in glioblastoma patients should pursue combination of therapies to help combat drug resistance. The emerging new data on the potential of plant-derived therapeutics should also be closely considered and further investigated.


Assuntos
Neoplasias Encefálicas/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos , Glioblastoma/tratamento farmacológico , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/antagonistas & inibidores , Transportadores de Cassetes de Ligação de ATP/metabolismo , Compostos Alílicos/uso terapêutico , Inibidores da Angiogênese/uso terapêutico , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Terapia Combinada , Metilases de Modificação do DNA/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/efeitos dos fármacos , Flavonoides/uso terapêutico , Alho/química , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/antagonistas & inibidores , MicroRNAs/uso terapêutico , Células-Tronco Neoplásicas/patologia , Proteínas Proto-Oncogênicas c-bcl-2/efeitos dos fármacos , RNA Interferente Pequeno/uso terapêutico , Retinoides/uso terapêutico , Sulfetos/uso terapêutico , Proteínas Supressoras de Tumor/efeitos dos fármacos
14.
Front Biosci (Landmark Ed) ; 16(1): 340-59, 2011 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-21196174

RESUMO

Histone deacetylases inhibitors (HDACi) have recently emerged as potent antitumor treatment modality. They are currently tested in many phase I, II and III clinical trials as single agents as wells as in combination schemes. They have demonstrated promising antitumor activity and favorable clinical outcome. Histone deacetylases (HDACs) are involved in the process of epigenetic regulation of gene expression. Epigenetic changes are believed to be crucial for the onset and progression of cancer and have recently gained remarkable attention. Since epigenetic regulation of gene expression is a reversible process, targeting histone deacetylases provides a good rationale for anticancer therapy. The acetylation status of histones regulates the organization of chromatin and the access of transcription factors. Moreover, functions of many non-histone proteins are controlled by acetylation. The broad and complicated influences of HDACi on various molecular processes may account for the observed pleiotropic effects. In this review we summarize recent advances in the understanding of biology of HDACs and mechanism of action of their inhibitors.


Assuntos
Antineoplásicos/uso terapêutico , Inibidores de Histona Desacetilases/uso terapêutico , Histona Desacetilases/fisiologia , Neoplasias/tratamento farmacológico , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Ensaios Clínicos como Assunto , Terapia Combinada , Enzimas Reparadoras do DNA/efeitos dos fármacos , Proteínas de Ligação a DNA/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/uso terapêutico , Epigênese Genética , Proteínas de Choque Térmico HSP90/efeitos dos fármacos , Histona Acetiltransferases/antagonistas & inibidores , Histona Acetiltransferases/metabolismo , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/genética , Histonas/metabolismo , Humanos , Metaloproteinase 2 da Matriz/efeitos dos fármacos , Metaloproteinase 9 da Matriz/efeitos dos fármacos , Neoplasias/genética , Neovascularização Patológica/fisiopatologia , Proteínas Nucleares/efeitos dos fármacos , Processamento de Proteína Pós-Traducional , Espécies Reativas de Oxigênio/metabolismo , Proteína Tumoral p73 , Proteína Supressora de Tumor p53/efeitos dos fármacos , Proteínas Supressoras de Tumor/efeitos dos fármacos
15.
Semin Radiat Oncol ; 20(4): 250-7, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20832017

RESUMO

DNA double-strand breaks (DSBs) are the most lethal type of DNA damage induced by ionizing radiation or chemotherapeutic drugs used to eradicate cancer cells. The ability of cancer cells to effectively repair DSBs significantly influences the outcome of therapeutic regimens. Therefore, a new and important area of clinical cancer research is the development of DNA repair inhibitors that can be used as radio- or chemosensitizers. Nonhomologous end joining (NHEJ) is the predominant pathway for the repair of radiation-induced DSBs. A series of recent reports indicates that the epidermal growth factor receptor (EGFR) or its downstream components may modulate NHEJ through direct interaction with the DNA repair enzyme, DNA-dependent protein kinase. Because EGFR is overexpressed or activated in many cancers, these findings provide a compelling rationale for combining radiotherapy with therapies that block EGFR or its downstream signaling components. In this review, we delineate how these novel connections between a cell-surface receptor (EGFR) and a predominantly nuclear event (NHEJ) provide vulnerable nodes that can be selectively targeted to improve cancer therapy.


Assuntos
Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Quebras de DNA de Cadeia Dupla/efeitos da radiação , Reparo do DNA , Receptores ErbB/antagonistas & inibidores , Neoplasias/tratamento farmacológico , Neoplasias/radioterapia , Radiossensibilizantes/farmacologia , Ciclo Celular , Dano ao DNA , Enzimas Reparadoras do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/efeitos da radiação , DNA de Neoplasias/efeitos dos fármacos , DNA de Neoplasias/efeitos da radiação , Humanos , Radioterapia (Especialidade)/métodos , Recombinação Genética , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/efeitos da radiação
17.
Fertil Steril ; 94(7): 2620-5.e1-5, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20557883

RESUMO

OBJECTIVE: To evaluate the effects of polycyclic aromatic hydrocarbon (PAH) exposure and four functional genetic polymorphisms in the nucleotide excision repair pathway, alone or combined, on sperm DNA integrity and male fertility. DESIGN: Retrospective case-only and case-control study. SETTING: One university and three centers of clinical reproductive medicine in the Jiangsu Province of China. PATIENT(S): Six hundred twenty infertile men and 273 controls were recruited for the study. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Exposure to PAHs was detected as urinary 1-hydroxypyrene level. Genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism, and sperm DNA damage was detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling assay with use of flow cytometry. RESULT(S): Increased sperm DNA damage was found to be associated significantly with increased urinary concentrations of 1-hydroxypyrene. We also observed that the xeroderma pigmentosum group A (XPA)-4 G/A polymorphism was associated with sperm DNA damage. Subjects homozygous for XPA-4 AA had significantly more sperm DNA damage compared with subjects for XPA-4 GG. Moreover, on the basis of a case-control study, a significant interaction was found between XPA-4 G/A polymorphism and PAH exposures on the sperm DNA damage risk (odds ratio = 2.86, 95% confidence interval = 1.77-4.61). CONCLUSION(S): We provide the first evidence for potential gene-environment interactions between nucleotide excision repair polymorphisms and PAH exposure on the sperm DNA damage and male factor infertility in men with no occupational exposure to PAHs.


Assuntos
Dano ao DNA , Reparo do DNA/genética , Infertilidade Masculina/induzido quimicamente , Exposição Paterna , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Polimorfismo Genético , Espermatozoides/efeitos dos fármacos , Adulto , Estudos de Casos e Controles , China/epidemiologia , Adutos de DNA/análise , Adutos de DNA/urina , Reparo do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/genética , Humanos , Infertilidade Masculina/epidemiologia , Infertilidade Masculina/genética , Infertilidade Masculina/urina , Masculino , Exposição Paterna/efeitos adversos , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/farmacologia , Hidrocarbonetos Policíclicos Aromáticos/urina , Polimorfismo Genético/efeitos dos fármacos , Polimorfismo Genético/fisiologia , Pirenos/análise , Estudos Retrospectivos , Análise do Sêmen , Espermatozoides/metabolismo
18.
Radiat Oncol ; 5: 8, 2010 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-20128919

RESUMO

BACKGROUND: The histamine receptor-1 (H1)-antagonist, loratadine has been shown to inhibit growth of human colon cancer xenografts in part due to cell cycle arrest in G2/M. Since this is a radiation sensitive phase of the cell cycle, we sought to determine if loratadine modifies radiosensitivity in several human tumor cell lines with emphasis on human colon carcinoma (HT29). METHODS: Cells were treated with several doses of loratadine at several time points before and after exposure to radiation. Radiation dose modifying factors (DMF) were determined using full radiation dose response survival curves. Cell cycle phase was determined by flow cytometry and the expression of the cell cycle-associated proteins Chk1, pChk1(ser345), and Cyclin B was analyzed by western blot. RESULTS: Loratadine pre-treatment of exponentially growing cells (75 microM, 24 hours) increased radiation-induced cytotoxicity yielding a radiation DMF of 1.95. However, treatment of plateau phase cells also yielded a DMF of 1.3 suggesting that mechanisms other than cell cycle arrest also contribute to loratadine-mediated radiation modification. Like irradiation, loratadine initially induced G2/M arrest and activation of the cell-cycle associated protein Chk1 to pChk1(ser345), however a subsequent decrease in expression of total Chk1 and Cyclin B correlated with abrogation of the G2/M checkpoint. Analysis of DNA repair enzyme expression and DNA fragmentation revealed a distinct pattern of DNA damage in loratadine-treated cells in addition to enhanced radiation-induced damage. Taken together, these data suggest that the observed effects of loratadine are multifactorial in that loratadine 1) directly damages DNA, 2) activates Chk1 thereby promoting G2/M arrest making cells more susceptible to radiation-induced DNA damage and, 3) downregulates total Chk1 and Cyclin B abrogating the radiation-induced G2/M checkpoint and allowing cells to re-enter the cell cycle despite the persistence of damaged DNA. CONCLUSIONS: Given this unique possible mechanism of action, loratadine has potential as a chemotherapeutic agent and as a modifier of radiation responsiveness in the treatment of cancer and, as such, may warrant further clinical evaluation.


Assuntos
Proteínas de Ciclo Celular/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/efeitos da radiação , Enzimas Reparadoras do DNA/efeitos dos fármacos , Loratadina/farmacologia , Radiossensibilizantes/farmacologia , Western Blotting , Células HT29 , Humanos , Tolerância a Radiação/efeitos dos fármacos
19.
J Chemother ; 21(1): 74-9, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19297277

RESUMO

Cochlear lateral wall damage is a side effect of cisplatin chemotherapy. Recent studies have shown that cisplatin treatment precipitates platinated DNA adducts in the cochlear lateral wall which suggest that DNA damage may contribute to ototoxicity. Platinated adducts are high-affinity substrates for the global genomic nucleotide excision repair (GG-NeR) pathway which is facilitated by xeroderma pigmentosum (Xp) complementing proteins, such as XpC, XpD and XpA. tumor biology has shown that in addition to stimulating GG-NeR, cisplatin may deplete telomerase reverse transcriptase (teRt). in the current study Fischer344 rats were treated with cisplatin (2 mg/kg/4 days, i.p.) and their cochleae harvested for immunohistochemistry. XpC, XpD and XpA expression increased while teRt expression decreased among cisplatin treated animals compared to vehicle control. these findings suggest that in addition to forming platinated adducts, cisplatin chemotherapy may up-regulate DNA repair proteins and modify teRt expression in the cochlear lateral wall.


Assuntos
Antineoplásicos/efeitos adversos , Cisplatino/efeitos adversos , Cóclea/efeitos dos fármacos , Cóclea/metabolismo , Enzimas Reparadoras do DNA/efeitos dos fármacos , Telomerase/efeitos dos fármacos , Animais , Proteínas de Transporte/biossíntese , Proteínas de Transporte/efeitos dos fármacos , Enzimas Reparadoras do DNA/biossíntese , Imuno-Histoquímica , Ratos , Ratos Endogâmicos F344 , Proteína de Xeroderma Pigmentoso Grupo A/biossíntese , Proteína de Xeroderma Pigmentoso Grupo A/efeitos dos fármacos
20.
J Neurooncol ; 92(2): 227-32, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19037596

RESUMO

We report a case of a 51-year-old woman with newly diagnosed glioblastoma multiforme (GBM) who was treated with surgery followed by the standard concomitant temozolomide (TMZ) and radiotherapy (RT). Although TMZ is generally safe and well-tolerated, she developed a sudden onset of prolonged and severe thrombocytopenia as the most prominent event of pancytopenia during the combined treatment, leading to discontinuation of the combined therapy. Thrombocytopenia lasted for more than 2 months with intensive, intermittent platelet transfusions. A bone marrow aspiration and biopsy performed after recovery of severe suppression still revealed reduced number of megakaryocytes. O(6)-methylguanine-DNA methyltransferase (MGMT) analyses showed methylated MGMT promoter in GBM, but unmethylated promoters in both peripheral blood leukocytes and bone marrow cells. This is the first report suggesting the irrelevance of MGMT status of normal hematopoietic cells to TMZ-induced severe thrombocytopenia and pancytopenia.


Assuntos
Neoplasias Encefálicas/terapia , Metilases de Modificação do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/efeitos dos fármacos , Glioblastoma/terapia , Pancitopenia/etiologia , Trombocitopenia/etiologia , Proteínas Supressoras de Tumor/efeitos dos fármacos , Antineoplásicos Alquilantes/efeitos adversos , Sequência de Bases , Western Blotting , Neoplasias Encefálicas/patologia , Terapia Combinada , Metilação de DNA/efeitos dos fármacos , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , Dacarbazina/efeitos adversos , Dacarbazina/análogos & derivados , Feminino , Glioblastoma/patologia , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos , Reação em Cadeia da Polimerase , Radioterapia/efeitos adversos , Temozolomida , Proteínas Supressoras de Tumor/genética
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