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1.
Yonsei Med J ; 59(6): 727-735, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29978609

RESUMO

PURPOSE: To investigate the effect of combined inhibition of protein kinase B (AKT) and SRC on the growth and metastatic potential of human pancreatic cancer cells. MATERIALS AND METHODS: AKT and SRC were inhibited using 10-DEBC and PP2, respectively. The expression of their messenger RNAs were down-regulated by specific small interfering RNA (siRNA). Changes in pancreatic cancer cell growth and metastatic potential were determined using a cell viability assay and a xenotransplant model of pancreatic cancer, as well as cell migration and invasion assays. Signal proteins were analyzed by Western blot. RESULTS: The inhibitors 10-DEBC and PP2 suppressed cell proliferation in a dose-dependent fashion in pancreatic cancer cell lines MIA PaCa-2 and PANC-1. The simultaneous inhibition of AKT and SRC at low concentrations resulted in a significant suppression of cell proliferation. Knockdown of AKT2 and SRC using siRNAs also significantly decreased cell proliferation. In a pancreatic cancer model, combined treatment with 10-DEBC and PP2 also significantly suppressed the growth of pancreatic cancer. Application of 10-DEBC with PP2 significantly reduced the metastatic potential of pancreatic cancer cells by inhibiting migration and invasion. The combined inhibition suppressed the phosphorylation of mTOR and ERK in pancreatic cancer cells. CONCLUSION: Combined targeting of AKT and SRC resulted in a synergistic efficacy against human pancreatic cancer growth and metastasis.


Assuntos
Movimento Celular/efeitos dos fármacos , Mitomicinas/farmacologia , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/patologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Quinases da Família src/antagonistas & inibidores , Western Blotting , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células , Sobrevivência Celular/efeitos dos fármacos , Sinergismo Farmacológico , Humanos , Terapia de Alvo Molecular , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Fosforilação/efeitos dos fármacos , Inibidores de Proteínas Quinases/administração & dosagem , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , RNA Interferente Pequeno/genética , Quinases da Família src/genética , Quinases da Família src/metabolismo
2.
Chem Res Toxicol ; 31(8): 762-771, 2018 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-30035537

RESUMO

Mitomycin C (MC) is an anticancer agent that alkylates DNA to form monoadducts and interstrand cross-links. Decarbamoylmitomycin C (DMC) is an analogue of MC lacking the carbamate on C10. The major DNA adducts isolated from treatment of culture cells with MC and DMC are N2-deoxyguanosine (dG) adducts and adopt an opposite stereochemical configuration at the dG-mitosene bond. To elucidate the molecular mechanisms of DMC-DNA alkylation, we have reacted short oligonucleotides, calf thymus, and M. luteus DNA with DMC using biomimetic conditions. These experiments revealed that DMC is able to form two stereoisomeric deoxyadenosine (dA) adducts with DNA under bifuntional reduction conditions and at low temperature. The dA-DMC adducts formed were detected and quantified by HPLC analysis after enzymatic digestion of the alkylated DNA substrates. Results revealed the following rules for DMC dA alkylation: (i) DMC dA adducts are formed at a 48- to 4-fold lower frequency than dG adducts, (ii) the 5'-phosphodiester linkage of the dA adducts is resistant to snake venom diesterase, (iii) end-chain dA residues are more reactive than internal ones in duplex DNA, and (iv) nucleophilic addition by dA occurs on both faces of DMC and the ratio of stereoisomeric dA adducts formed is dependent on the end bases located at the 3' or 5' position. A key finding was to discover that temperature plays a determinant role in the regioselectivity of duplex DNA alkylation by DMC: at 0 °C, both dA and dG alkylation occur, whereas at 37 °C, DMC preferentially alkylates dG residues.


Assuntos
Adutos de DNA/química , DNA/química , Desoxiadenosinas/química , Mitomicinas/química , Alquilação , Animais , Bovinos , Cromatografia Líquida de Alta Pressão , Isomerismo , Espectrometria de Massas/métodos , Reprodutibilidade dos Testes , Espectrofotometria Ultravioleta , Sulfatos/química , Temperatura
3.
Chemistry ; 24(50): 13278-13289, 2018 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-29958326

RESUMO

Mitomycin C (MC), an antitumor drug, and decarbamoylmitomycin C (DMC), a derivative of MC, alkylate DNA and form deoxyguanosine monoadducts and interstrand crosslinks (ICLs). Interestingly, in mammalian culture cells, MC forms primarily deoxyguanosine adducts with a 1"-R stereochemistry at the guanine-mitosene bond (1"-α) whereas DMC forms mainly adducts with a 1"-S stereochemistry (1"-ß). The molecular basis for the stereochemical configuration exhibited by DMC has been investigated using biomimetic synthesis. Here, we present the results of our studies on the monoalkylation of DNA by DMC. We show that the formation of 1"-ß-deoxyguanosine adducts requires bifunctional reductive activation of DMC, and that monofunctional activation only produces 1"-α-adducts. The stereochemistry of the deoxyguanosine adducts formed is also dependent on the regioselectivity of DNA alkylation and on the overall DNA CG content. Additionally, we found that temperature plays a determinant role in the regioselectivity of duplex DNA alkylation by mitomycins: At 0 °C, both deoxyadenosine (dA) and deoxyguanosine (dG) alkylation occur whereas at 37 °C, mitomycins alkylate dG preferentially. The new reaction protocols developed in our laboratory to investigate DMC-DNA alkylation raise the possibility that oligonucleotides containing DMC 1"-ß-deoxyguanosine adducts at a specific site may be synthesized by a biomimetic approach.


Assuntos
DNA/química , Mitomicinas/química , Alquilação , Animais , Sequência de Bases , Cromatografia Líquida de Alta Pressão , Adutos de DNA/análise , Adutos de DNA/química , DNA Bacteriano/química , Desoxiadenosinas/química , Desoxiguanosina/química , Camundongos , Micrococcus luteus/genética , Mitomicina/química , Estereoisomerismo , Temperatura
4.
Curr Opin Pharmacol ; 41: 20-26, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29679802

RESUMO

DNA crosslinking agents make up a broad class of chemotherapy agents that target rapidly dividing cancer cells by disrupting DNA synthesis. These drugs differ widely in both chemical structure and biological effect. In cells, crosslinking agents can form multiple types of DNA lesions with varying efficiencies. Inter-strand crosslinks (ICLs) are considered to be the most cytotoxic lesion, creating a covalent roadblock to replication and transcription. Despite over 50 years in the clinic, the use of crosslinking agents that specialize in the formation of ICLs remains limited, largely due to high toxicity in patients. Current ICL-based therapeutics have focused on late-stage and drug-resistant tumors, or localized treatments that limit exposure. In this article, we review the development of clinical crosslinking agents, our understanding of how cells respond to different lesions, and the potential to improve ICL-based chemotherapeutics in the future.


Assuntos
Antineoplásicos/uso terapêutico , Reagentes para Ligações Cruzadas/uso terapêutico , Neoplasias/tratamento farmacológico , Antineoplásicos/farmacologia , Reagentes para Ligações Cruzadas/farmacologia , DNA/efeitos dos fármacos , Furocumarinas/farmacologia , Furocumarinas/uso terapêutico , Humanos , Mecloretamina/análogos & derivados , Mecloretamina/uso terapêutico , Mitomicinas/farmacologia , Mitomicinas/uso terapêutico
5.
Chemistry ; 24(23): 6030-6035, 2018 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-29504661

RESUMO

Mitomycin C (MC), a potent antitumor drug, and decarbamoylmitomycin C (DMC), a derivative lacking the carbamoyl group, form highly cytotoxic DNA interstrand crosslinks. The major interstrand crosslink formed by DMC is the C1'' epimer of the major crosslink formed by MC. The molecular basis for the stereochemical configuration exhibited by DMC was investigated using biomimetic synthesis. The formation of DNA-DNA crosslinks by DMC is diastereospecific and diastereodivergent: Only the 1''S-diastereomer of the initially formed monoadduct can form crosslinks at GpC sequences, and only the 1''R-diastereomer of the monoadduct can form crosslinks at CpG sequences. We also show that CpG and GpC sequences react with divergent diastereoselectivity in the first alkylation step: 1"S stereochemistry is favored at GpC sequences and 1''R stereochemistry is favored at CpG sequences. Therefore, the first alkylation step results, at each sequence, in the selective formation of the diastereomer able to generate an interstrand DNA-DNA crosslink after the "second arm" alkylation. Examination of the known DNA adduct pattern obtained after treatment of cancer cell cultures with DMC indicates that the GpC sequence is the major target for the formation of DNA-DNA crosslinks in vivo by this drug.


Assuntos
DNA/química , Mitomicina/farmacologia , Mitomicinas/química , Alquilação , Reagentes para Ligações Cruzadas/química , Adutos de DNA , Dano ao DNA , Humanos , Estereoisomerismo
6.
Chem Res Toxicol ; 29(5): 933-9, 2016 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-27082015

RESUMO

Mitomycin C (MC) is a cytotoxic and mutagenic antitumor agent that alkylates DNA upon reductive activation. 2,7-Diaminomitosene (2,7-DAM) is a major metabolite of MC in tumor cells, which also alkylates DNA. MC forms seven DNA adducts, including monoadducts and inter- and intrastrand cross-links, whereas 2,7-DAM forms two monoadducts. Herein, the biological effects of the dG-N(2) adducts formed by MC and 2,7-DAM have been compared by constructing single-stranded plasmids containing these adducts and replicating them in human embryonic kidney 293T cells. Translesion synthesis (TLS) efficiencies of dG-N(2)-MC and dG-N(2)-2,7-DAM were 38 ± 3 and 27 ± 3%, respectively, compared to that of a control plasmid. This indicates that both adducts block DNA synthesis and that dG-N(2)-2,7-DAM is a stronger replication block than dG-N(2)-MC. TLS of each adducted construct was reduced upon siRNA knockdown of pol η, pol κ, or pol ζ. For both adducts, the most significant reduction occurred with knockdown of pol κ, which suggests that pol κ plays a major role in TLS of these dG-N(2) adducts. Analysis of the progeny showed that both adducts were mutagenic, and the mutation frequencies (MF) of dG-N(2)-MC and dG-N(2)-2,7-DAM were 18 ± 3 and 10 ± 1%, respectively. For both adducts, the major type of mutation was G → T transversions. Knockdown of pol η and pol ζ reduced the MF of dG-N(2)-MC and dG-N(2)-2,7-DAM, whereas knockdown of pol κ increased the MF of these adducts. This suggests that pol κ predominantly carries out error-free TLS, whereas pol η and pol ζ are involved in error-prone TLS. The largest reduction in MF by 78 and 80%, respectively, for dG-N(2)-MC and dG-N(2)-2,7-DAM constructs occurred when pol η, pol ζ, and Rev1 were simultaneously knocked down. This result strongly suggests that, unlike pol κ, these three TLS polymerases cooperatively perform the error-prone TLS of these adducts.


Assuntos
Desoxiguanosina/química , Mitomicina/química , Mitomicinas/química , Células HEK293 , Humanos
7.
Bioorg Chem ; 65: 90-9, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26894558

RESUMO

Mitomycin C (MC) and Decarbamoylmitomycin C (DMC) - a derivative of MC lacking the carbamate on C10 - are DNA alkylating agents. Their cytotoxicity is attributed to their ability to generate DNA monoadducts as well as intrastrand and interstrand cross-links (ICLs). The major monoadducts generated by MC and DMC in tumor cells have opposite stereochemistry at carbon one of the guanine-mitosene bond: trans (or alpha) for MC and cis (or beta) for DMC. We hypothesize that local disruptions of DNA structure from trans or cis adducts are responsible for the different biochemical responses produced by MC and DMC. Access to DNA substrates bearing cis and trans MC/DMC lesions is essential to verify this hypothesis. Synthetic oligonucleotides bearing trans lesions can be obtained by bio-mimetic methods. However, this approach does not yield cis adducts. This report presents the first chemical synthesis of a cis mitosene DNA adduct. We also examined the stereopreference exhibited by the two drugs at the mononucleotide level by analyzing the formation of cis and trans adducts in the reaction of deoxyguanosine with MC or DMC using a variety of activation conditions. In addition, we performed Density Functional Theory calculations to evaluate the energies of these reactions. Direct alkylation under autocatalytic or bifunctional conditions yielded preferentially alpha adducts with both MC and DMC. DFT calculations showed that under bifunctional activation, the thermodynamically favored adducts are alpha, trans, for MC and beta, cis, for DMC. This suggests that the duplex DNA structure may stabilize/oriente the activated pro-drugs so that, with DMC, formation of the thermodynamically favored beta products are possible in a cellular environment.


Assuntos
Adutos de DNA/síntese química , Desoxiguanosina/síntese química , Mitomicina/síntese química , Mitomicinas/síntese química , Adutos de DNA/química , Desoxiguanosina/química , Mitomicina/química , Mitomicinas/química , Conformação Molecular , Teoria Quântica
8.
Bioorg Med Chem ; 23(23): 7378-85, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26541587

RESUMO

Two synthetic aziridinomitosenes (AZMs), Me-AZM and H-AZM, structurally related to mitomycin C (MC) were evaluated for their anticancer activity against six cancer cell lines (HeLa, Jurkat, T47D, HepG2, HL-60, and HuT-78) and tested for their DNA-modifying abilities in Jurkat cells. Cytotoxicity assays showed that Me-AZM is up to 72-fold and 520-fold more potent than MC and H-AZM, respectively. Me-AZM also demonstrated increased DNA modification over MC and H-AZM in alkaline COMET and Hoechst fluorescence assays that measured crosslinks in cellular DNA. Me-AZM and H-AZM treatment of Jurkat cells was found to sponsor significant DNA-protein crosslinks using a K-SDS assay. The results clearly indicate that the AZM C6/C7 substitution pattern plays an important role in drug activity and supports both DNA-DNA and DNA-protein adduct formation as mechanisms for inducing cytotoxic effects.


Assuntos
Antineoplásicos/farmacologia , Reagentes para Ligações Cruzadas/farmacologia , DNA/metabolismo , Mitomicinas/farmacologia , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaio Cometa , Reagentes para Ligações Cruzadas/química , Adutos de DNA/metabolismo , Humanos , Mitomicinas/química , Relação Estrutura-Atividade
9.
Cell Cycle ; 14(5): 744-54, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25565400

RESUMO

Interstrand crosslinks induce DNA replication fork stalling that in turn activates the ATR-dependent checkpoint and DNA repair on nuclear chromatin. Mitomycin C (MC) and Decarbamoyl Mitomycin C (DMC) induce different types of DNA crosslinks with DMC being a more cytotoxic agent. We previously reported that the novel DMC induced ß-interstrand DNA crosslinks induce a p53-independent form of cell death. The p53-independent DMC cytotoxicity associates with the activation, and subsequent depletion, of Chk1. In this study we further dissect the novel DMC signal transduction pathway and asked how it influences chromatin-associated proteins. We found that treatment with DMC, but not MC, stimulated the disassociation of ATR from chromatin and re-localization of ATR to the cytoplasm. The chromatin eviction of ATR was coupled with the formation of nuclear Rad51 foci and the phosphorylation of Chk1. Furthermore, DMC but not MC, activated expression of gadd45α mRNA. Importantly, knocking down p53 via shRNA did not inhibit the DMC-induced disassociation of ATR from chromatin or reduce the activation of transcription of gadd45α. Our results suggest that DMC induces a p53-independent disassociation of ATR from chromatin that facilitates Chk1 checkpoint activation and Rad51 chromatin recruitment. Our findings provide evidence that ATR chromatin eviction in breast cancer cells is an area of study that should be focused on for inducing p53-independent cell death.


Assuntos
Cromatina/metabolismo , Mitomicinas/farmacologia , Proteína Supressora de Tumor p53/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteínas de Ciclo Celular/metabolismo , Morte Celular/efeitos dos fármacos , Quinase 1 do Ponto de Checagem , DNA/metabolismo , Dano ao DNA , Recombinação Homóloga/efeitos dos fármacos , Humanos , Células MCF-7 , Modelos Biológicos , Proteínas Nucleares/metabolismo , Fosforilação/efeitos dos fármacos , Fosfosserina/metabolismo , Ligação Proteica/efeitos dos fármacos , Proteínas Quinases/metabolismo , Rad51 Recombinase/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
10.
Braz. dent. j ; 25(6): 538-542, Nov-Dec/2014. tab
Artigo em Inglês | LILACS | ID: lil-732251

RESUMO

The aim of this study was to evaluate the degree of conversion (DC) and the cytotoxicity of photo-cured experimental resin composites containing 4-(N,N-dimethylamino)phenethyl alcohol (DMPOH) combined to the camphorquinone (CQ) compared with ethylamine benzoate (EDAB). The resin composites were mechanically blended using 35 wt% of an organic matrix and 65 wt% of filler loading. To this matrix was added 0.2 wt% of CQ and 0.2 wt% of one of the reducing agents tested. 5x1 mm samples (n=5) were previously submitted to DC measurement and then pre-immersed in complete culture medium without 10% (v/v) bovine serum for 1 h or 24 h at 37 °C in a humidifier incubator with 5% CO2 and 95% humidity to evaluate the cytotoxic effects of experimental resin composites using the MTT assay on immortalized human keratinocytes cells. As a result of absence of normal distribution, the statistical analysis was performed using the nonparametric Kruskal-Wallis to evaluate the cytotoxicity and one-way analysis of variance to evaluate the DC. For multiple comparisons, cytotoxicity statistical analyses were submitted to Student-Newman-Keuls and DC analysis to Tukey's HSD post-hoc test (=0.05). No significant differences were found between the DC of DMPOH (49.9%) and EDAB (50.7%). 1 h outcomes showed no significant difference of the cell viability between EDAB (99.26%), DMPOH (94.85%) and the control group (100%). After 24 h no significant difference were found between EDAB (48.44%) and DMPOH (38.06%), but significant difference was found compared with the control group (p>0.05). DMPOH presented similar DC and cytotoxicity compared with EDAB when associated with CQ.


O objetivo deste estudo foi avaliar o grau de conversão (GC) e a citotoxicidade de resinas compostas experimentais utilizando o álcool 4-(N,N-dimetilamino) fenil etílico (DMPOH) associado à canforoquinona (CQ) como sistema fotoiniciador (SF) comparado à versão comercial utilizando o benzoato de etilamina (EDAB). Para tanto, as resinas compostas experimentais foram mecanicamente misturadas utilizando (em peso): 35% de matriz orgânica e 65% em peso de partículas de carga. Posteriormente, foram adicionados 0,2% de CQ e 0,2% de um dos agentes redutores testados. Amostras de 5 x 1 mm (n=5) foram previamentes submetidas à análise de GC e posteriormente, esterilizadas e colocadas no meio de cultura completo sem soro fetal bovino estéril por 1 h ou 24 h a 37 °C em encubadora com 5% de CO2 and 95% de umidade para avaliar os efeitos citotóxicos das resinas compostas experimentais utilizando o método MTT emcélulas células humanas imortalizadas de queratinócitos. Os dados de citotoxicidade foram submetidos à análise estatística de Kruskal-Wallis e de GC à análise de variância com um fator. Em virtude da ausência de normalidade, a análise estatística da citotoxicidade foi realizada utilizando-se o teste não-paramétrico de Kruskal-Wallis. Para o GC, os dados foram submetidos à análise de variaância de 1 fator. Posteriormente para múltiplas comparações, os dados de citotoxicidade foram submetidos ao teste Student-Newman-Keuls e o GC ao teste de Tukey's HSD post-hoc (=0.05). Não foi observada diferença estatística entre o GC de DMPOH (49,9%) e EDAB (50,7%). Para os resultados de 1 h não houve diferença na viabilidade celular entre EDAB (99,26%), DMPOH (94,85%) e o grupo controle (100%). Após 24 h, nenhuma diferença estatística foi encontrada entre EDAB (48,44%) e DMPOH (38,06%), entretanto, diferença significativa foi encontrada em relação ao grupo controle (p>0,05). O DMPOH apresentou GC e citotoxicidade semelhante à EDAB quando associado à CQ.


Assuntos
Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias do Colo/tratamento farmacológico , Neoplasias Gástricas/tratamento farmacológico , Administração Oral , Cisplatino/administração & dosagem , Esquema de Medicação , Doxorrubicina/administração & dosagem , Etoposídeo/administração & dosagem , Floxuridina/administração & dosagem , Neoplasias da Vesícula Biliar/tratamento farmacológico , Infusões Intravenosas , Mitomicina , Mitomicinas/administração & dosagem , Neoplasias Esplênicas/tratamento farmacológico
11.
Braz. j. phys. ther. (Impr.) ; 18(6): 572-579, 09/01/2015. tab, graf
Artigo em Inglês | LILACS | ID: lil-732350

RESUMO

Background: Partial body weight support (BWS) systems have been broadly used with treadmills as a strategy for gait training of individuals with gait impairments. Considering that we usually walk on level ground and that BWS is achieved by altering the load on the plantar surface of the foot, it would be important to investigate some ground reaction force (GRF) parameters in healthy individuals walking on level ground with BWS to better implement rehabilitation protocols for individuals with gait impairments. Objective: To describe the effects of body weight unloading on GRF parameters as healthy young adults walked with BWS on level ground. Method: Eighteen healthy young adults (27±4 years old) walked on a walkway, with two force plates embedded in the middle of it, wearing a harness connected to a BWS system, with 0%, 15%, and 30% BWS. Vertical and horizontal peaks and vertical valley of GRF, weight acceptance and push-off rates, and impulse were calculated and compared across the three experimental conditions. Results: Overall, participants walked more slowly with the BWS system on level ground compared to their normal walking speed. As body weight unloading increased, the magnitude of the GRF forces decreased. Conversely, weight acceptance rate was similar among conditions. Conclusions: Different amounts of body weight unloading promote different outputs of GRF parameters, even with the same mean walk speed. The only parameter that was similar among the three experimental conditions was the weight acceptance rate. .


Assuntos
Idoso , Humanos , Masculino , Adenocarcinoma/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Retais/patologia , Adenocarcinoma/secundário , Tolerância a Medicamentos , Floxuridina/administração & dosagem , Neoplasias Pulmonares/secundário , Mitomicina , Mitomicinas/administração & dosagem , Indução de Remissão
12.
Angew Chem Int Ed Engl ; 53(35): 9302-5, 2014 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-25044229

RESUMO

A DNA crosslinking approach, which is distinct but related to the double alkylation by mitomycin C, involving a novel electrophilic spiro-cyclopropane intermediate is hypothesized. Rational design and substantial structural simplification permitted the expedient chemical synthesis and rapid discovery of MTSB-6, a mitomycin C analogue which is twice as potent as mitomycin C against the prostate cancer cells. MTSB-6 shows improvements in its selective action against noncancer prostate cells over mitomycin C. This hypothesis-driven discovery opens novel yet synthetically accessible mitosene structural space for discovering more potent and less toxic therapeutic candidates.


Assuntos
Mitomicina/farmacologia , Mitomicinas/química , Mitomicinas/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Concentração Inibidora 50 , Mitomicina/química , Mitomicinas/síntese química , Estrutura Molecular , Relação Estrutura-Atividade
13.
Acta Oncol ; 53(10): 1347-55, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24909504

RESUMO

BACKGROUND: Before the advent of neoadjuvant chemotherapy, radiotherapy and surgery alone were associated with a high risk of uncontrolled locoregional relapses in locally advanced breast cancer (LABC). MATERIAL AND METHODS: In the 1990s we initiated two neoadjuvant protocols, where patients with LABC were given either doxorubicin qW or 5-fluorouracil/mitomycin (FUMI) q3W to shrink the tumours prior to mastectomy and postoperative radiotherapy. Previously, we reported TP53 mutation status to predict a poor response to chemotherapy. Here, we present the long-term survival data, with a follow-up of 20 years in the doxorubicin (n = 90) and 15 years in the FUMI trial (n = 34). RESULTS: Patients in the doxorubicin trial with TP53-mutated tumours experienced a shorter recurrence-free (RFS; 14 vs. 83 months, p < 0.001) and overall survival (OS; 35 vs. 90 months, p < 0.001) than patients with TP53 wt tumours. Similarily, TP53 mutations were associated with a shorter OS (22 vs. 80 months, p = 0.03) and a tendency to shorter RFS (17 vs. 33 months, p = 0.06) in patients treated with FUMI. Furthermore, axillary lymph node metastases predicted shorter OS, but only in patients treated with doxorubicin (49 vs. 142 months, p < 0.04). Applying multivariate analysis, TP53 mutations predicted inferior RFS (p < 0.001) as well as OS (p < 0.001), independently of axillary lymph node status. Isolated local recurrences, without simultaneous distant metastases, occurred in seven patients only in the two trials. Interestingly, chest wall radiation fibrosis predicted improved OS (p = 0.004). CONCLUSION: TP53 inactivating mutations are associated with an inferior long-term prognosis in patients with LABC treated with conventional chemotherapy.


Assuntos
Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama , Genes p53 , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Axila , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Doxorrubicina/uso terapêutico , Feminino , Fluoruracila/administração & dosagem , Seguimentos , Humanos , Metástase Linfática , Pessoa de Meia-Idade , Mitomicinas/administração & dosagem , Terapia Neoadjuvante/métodos , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/mortalidade , Prognóstico , Fatores de Tempo
14.
PLoS One ; 9(2): e88828, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24586407

RESUMO

p53 is a transcription factor that regulates the response to cellular stress. Mammalian p53 functions as a tumor suppressor. The C. elegans p53, cep-1, regulates DNA-damage induced germline cell death by activating the transcription of egl-1 and ced-13. We used the C. elegans model to investigate how, in the whole animal, different forms of DNA damage can induce p53-dependent versus p53-independent cell death and DNA repair. DNA damage was induced by ultraviolet type C (UVC) radiation, or 10-decarbamoyl mitomycin C (DMC, an agent known to induce mammalian p53-independent cell death). Wild-type or cep-1 loss-of-function mutant animals were assayed for germline cell death and DNA lesions. Wild-type animals displayed greater removal of UVC-lesions over time, whereas cep-1 mutant animals displayed increased UVC-lesion retention. The cep-1 mutation increased UVC-lesion retention directly correlated with a reduction of progeny viability. Consistent with DMC inducing p53-independent cell death in mammalian cells DMC induced a C. elegans p53-independent germline cell death pathway. To examine the influence of wild-type CEP-1 and DNA damage on C. elegans tumors we used glp-1(ar202gf)/Notch germline tumor mutants. UVC treatment of glp-1 mutant animals activated the CEP-1 target gene egl-1 and reduced tumor size. In cep-1(gk138);glp-1(ar202gf) animals, UVC treatment resulted in increased susceptibility to lesions and larger tumorous germlines. Interestingly, the partial knockdown of bec-1 in adults resulted in a CEP-1-dependent increase in germline cell death and an increase in DNA damage. These results strongly support cross-talk between BEC-1 and CEP-1 to protect the C. elegans genome.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/fisiologia , Reparo do DNA/fisiologia , Regulação da Expressão Gênica/genética , Proteína Supressora de Tumor p53/metabolismo , Proteínas de Transporte Vesicular/metabolismo , Animais , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Caenorhabditis elegans/genética , Dano ao DNA/efeitos da radiação , Primers do DNA/genética , Reparo do DNA/genética , Células Germinativas/efeitos dos fármacos , Células Germinativas/fisiologia , Mitomicinas/farmacologia , Interferência de RNA , Proteínas Repressoras/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Raios Ultravioleta
15.
J Org Chem ; 78(12): 6245-52, 2013 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-23721078

RESUMO

The preparation of trans-2,3-disubstituted indolines from 1-azido-2-allylbenzene derivatives via a diastereoselective radical cascade using ethyl iodoacetate and triethylborane is described. Further lactamization afforded substituted benzopyrrolizidinones with excellent diastereomeric ratios. The radical cascade/lactamization sequence was efficiently applied to the synthesis of a 3-oxo-leucomitosane related to the mitomycin family of alkaloids.


Assuntos
Compostos Alílicos/química , Derivados de Benzeno/química , Indóis/síntese química , Mitomicinas/síntese química , Boranos/química , Iodoacetatos/química , Estrutura Molecular , Estereoisomerismo
17.
Bioorg Chem ; 48: 1-7, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23639828

RESUMO

The anticancer drug mitomycin C produces cytotoxic effects after being converted to a highly reactive bis-electrophile by a reductive activation, a reaction that a number of 1-electron or 2-electron oxidoreductase enzymes can perform in cells. Several reports in the literature indicate that ascorbic acid can modulate the cytotoxic effects of mitomycin C, either potentiating or inhibiting its effects. As ascorbic acid is a reducing agent that is known to be able to reduce quinones, it could be possible that the observed modulatory effects are a consequence of a direct redox reduction between mitomycin C and ascorbate. To determine if this is the case, the reaction between mitomycin C and ascorbate was studied using UV/Vis spectroscopy and LC/MS. We also studied the reaction of ascorbate with mitomycin A, a highly toxic member of the mitomycin family with a higher redox potential than mitomycin C. We found that ascorbate is capable to reduce mitomycin A efficiently, but it reduces mitomycin C rather inefficiently. The mechanisms of activation have been elucidated based on the kinetics of the reduction and on the analysis of the mitosene derivatives formed after the reaction. We found that the activation occurs by the interplay of three different mechanisms that contribute differently, depending on the pH of the reaction. As the reduction of mitomycin C by ascorbate is rather inefficiently at physiologically relevant pH values we conclude that the modulatory effect of ascorbate on the cytotoxicity of mitomycin C is not the result of a direct redox reaction and therefore this modulation must be the consequence of other biochemical mechanisms.


Assuntos
Ácido Ascórbico/química , Mitomicina/química , Mitomicinas/química , Animais , Células CHO , Sobrevivência Celular/efeitos dos fármacos , Cricetinae , Cricetulus , Concentração de Íons de Hidrogênio , Cinética , Mitomicina/toxicidade , Mitomicinas/toxicidade , Oxirredução , Quinonas/química , Espectrofotometria Ultravioleta
18.
Bioorg Med Chem Lett ; 22(23): 7198-200, 2012 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-23079525

RESUMO

We report here the synthesis of two amino precursors for the production of mitomycin C and 10-decarbamoylmitomycin C DNA adducts with opposite stereochemistry at C-1. The triamino mitosene precursors were synthesized in 5 steps from mitomycin C. In addition synthesis of the major mitomycin C-DNA adduct has been accomplished via coupling of a triaminomitosene with 2-fluoro-O(6)-(2-p-nitrophenylethyl)deoxyinosine followed by deprotection at the N(2) and O(6) positions.


Assuntos
Adutos de DNA/química , Mitomicina/química , Mitomicinas/química , Adutos de DNA/síntese química , Isomerismo , Mitomicina/síntese química , Termodinâmica
19.
Arch Pharm Res ; 35(9): 1629-37, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23054720

RESUMO

We report the studies on nucleophilic activation and DNA alkylation of a cyclic disulfide mitomycin dimer, 7-N,7'-N'-(1″,2″-dithiepanyl-3″,7″-dimethylenyl)bismitomycin C (6) along with a diol mitomycin dimer, 7-N,7'-N'-(2″,6″-dihydroxy-1″,7″-heptanediyl)bismitomycin C (7). We wished to see if disulfide mitomycin 6 undergoes efficient nucleophilic activation and corresponding formation of DNA interstrand cross-link (DNA ISC) products compared to diol mitomycin 7. Mitomycin 6 is a dimer connected by a seven-membered cyclic disulfide (a 1,2-dithiepane) linker, and mitomycin 7 is also a dimer containing 2,6-dihydroxyheptane linker that was employed as a reference one to identify the effect of disulfide unit in 6. Through kinetic studies using solvolysis reaction, we found that 6 underwent much faster nucleophilic activation by Et3P compared to 7, and that the enhanced activation rates were induced by the disulfide unit in 6. These findings led us to propose a nucleophilic activation mechanism for 6. We further demonstrated that 6 produced much higher levels of DNA ISC (86%) by the action of Et3P compared with 7 (5%) and 1 (4%). Therefore, we have concluded that 6 was highly efficient for nucleophilic activation and DNA ISC formation due to the key role of cyclic disulfide unit in 6.


Assuntos
Antibióticos Antineoplásicos/química , Antineoplásicos Alquilantes/química , Adutos de DNA/análise , DNA/química , Mitomicinas/química , Alquilação/efeitos dos fármacos , Catálise , DNA/metabolismo , Ditiotreitol/química , Eletroforese em Gel de Ágar , Glutationa/química , Hidrólise/efeitos dos fármacos , Indicadores e Reagentes/química , Cinética , Fosfinas/química , Plasmídeos/química , Plasmídeos/metabolismo , Relação Estrutura-Atividade
20.
Arch Pharm Res ; 35(8): 1413-20, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22941484

RESUMO

We report the design and synthesis of two new mitomycin dimers, 7-N,7'-N'-(1″,2″-dithiepanyl-3″,7″-dimethylenyl)bismitomycin C (8) and 7-N,7'-N'-(2″,6″-dihydroxy-1″,7″-heptanediyl)bismitomycin C (9). Mitomycins 8 and 9 are dimers connected by a seven-membered cyclic disulfide (a 1,2-dithiepane) and a 2,6-dihydroxyheptane linkers, respectively. Mitomycin 8 was designed to undergo efficient nucleophilic activation and following alkylation to give DNA adducts such as DNA interstrand cross-link (DNA ISC) adducts. The key moiety in 8 is a seven-membered cyclic disulfide linker that can generate two thiol groups in a molecule through disulfide cleavage. The two thiols can serve as probes to activate two mitomycin rings by intramolecular cyclization to quinone rings. The mitomycin 8 was synthesized using mitomycin A (1) and the key intermediate, cyclic disulfide 11 that was prepared through a nine-step synthetic sequence from 1,6-heptadiene (12). The diol mitomycin 9 was also synthesized from 1 and diamine salt 15.


Assuntos
Antibióticos Antineoplásicos/química , Mitomicinas/química , Antibióticos Antineoplásicos/síntese química , Dimerização , Mitomicinas/síntese química
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