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1.
Front Psychol ; 15: 1338193, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38966736

RESUMO

Objectives: Disclosing information on diagnosis, prognosis and treatment is a delicate process in oncology, although awareness levels have over time increased in people with cancer. However, individual characteristics should be considered when communicating difficult information. We conducted a multicentric study to explore the moderating role of coping styles on the relationship between information about cancer, quality of life and psychological distress. Methods: In the period between October 2015 and February 2016, 288 patients with a diagnosis of a solid tumor were recruited from seven Italian oncology units. All participants were administered the Distress Thermometer (DT), the Mini-Mental Adjustment to Cancer (Mini-MAC), the European Organization for Research and Treatment of Cancer (EORTC) Core Quality of Life Questionnaire (QLQ-C30), and the EORTC QLQ 25-item information module (INFO25). We explored the moderating effect of coping style with quality of life (QoL) and distress (DT) as dependent variables and information on cancer treatment as independent variable. Results: Low levels of anxious preoccupation significantly moderated the relationship between information on treatment and QoL (R2 6%, p < 0.001), while low and medium levels of hopelessness significantly moderated the relationship between information on treatment and DT (R2 = 14%, p = 0.033). Adaptive coping strategies, such as fighting spirit and fatalism, and borderline strategies such as avoidance, did not play a role in this relationship. Conclusion: Taking into account and evaluating coping mechanisms in cancer care is a priority when disclosing information on treatments, in order to tailor communication style to individual features.

2.
J Natl Cancer Inst ; 89(16): 1217-23, 1997 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-9274917

RESUMO

BACKGROUND: Although doxorubicin remains one of the most effective agents for the treatment of solid tumors, there is an intensive effort to synthesize doxorubicin analogues (compounds with similar chemical structures) that may have improved antitumor properties. We have synthesized a novel doxorubicin disaccharide analogue (MEN 10755) and have characterized some of its relevant biochemical, biologic, and pharmacologic properties. METHODS: The antitumor activity of this compound (MEN 10755) was studied in a panel of human tumor xenografts, including xenografts of A2780 ovarian tumor cells, MX-1 breast carcinoma cells, and POVD small-cell lung cancer cells. MEN 10755 was compared with doxorubicin according to the optimal dose and schedule for each drug. The drug's cytotoxic effects, induction of DNA damage, and intracellular accumulation were studied in A2780 cells. DNA cleavage mediated by the enzyme topoisomerase II was investigated in vitro by incubating fragments of simian virus 40 DNA with the purified enzyme at various drug concentrations and analyzing the DNA cleavage-intensity patterns. Drug-induced apoptosis (programmed cell death) in tumors was determined with the use of MX-1 and POVD tumor-bearing athymic Swiss nude mice. RESULTS: MEN 10755 was more effective than doxorubicin as a topoisomerase II poison and stimulated DNA fragmentation at lower intracellular concentrations. In addition, MEN 10755 exhibited striking antitumor activity in the treatment of human tumor xenografts, including those of the doxorubicin-resistant breast carcinoma cell line MX-1. CONCLUSIONS: The high antitumor activity of MEN 10755 in human tumor xenografts, including doxorubicin-resistant xenografts, and its unique pharmacologic and biologic properties make this disaccharide analogue a promising candidate for clinical evaluation.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , DNA Topoisomerases Tipo II/efeitos dos fármacos , DNA de Neoplasias/efeitos dos fármacos , Doxorrubicina/análogos & derivados , Neoplasias Experimentais/tratamento farmacológico , Animais , Neoplasias da Mama/tratamento farmacológico , Carcinoma de Células Pequenas/tratamento farmacológico , Dano ao DNA , Dissacarídeos/síntese química , Doxorrubicina/síntese química , Feminino , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Camundongos , Camundongos Nus , Neoplasias Experimentais/genética , Neoplasias Ovarianas/tratamento farmacológico , Fatores de Tempo , Transplante Heterólogo
3.
Cancer Res ; 56(3): 556-62, 1996 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-8564971

RESUMO

P53 status may be a determinant of chemosensitivity of tumor cells; however, its involvement in cellular resistance to cisplatin remains uncertain. To investigate the relationships between p53 and the development of resistance to cisplatin, the p53 gene status was studied in ovarian carcinoma cell systems which included two cisplatin-resistant variants (IGROV-1/Pt 0.5 and IGROV-1/Pt 1) selected in vitro after prolonged drug exposure of the cisplatin-sensitive parental IGROV-1 cell line. IGROV-1/Pt 0.5 and IGROV-1/Pt 1 cell lines exhibited a degree of resistance of approximately 6 and 14, respectively, following 96-h exposure to the drug and were cross-resistant to other DNA-damaging agents (ionizing radiation and melphalan). Resistance to cisplatin paralleled a reduced cell susceptibility to cisplatin-induced apoptosis. DNA single-strand conformation polymorphism analysis of exons 5-9 demonstrated the presence of two mutants alleles at exon 8 in the two resistant cell lines, in contrast to the parental IGROV-1 cell line which exhibited the wild-type p53 gene. Direct DNA sequencing revealed that the mutations consist of two nucleotide changes in the DNA-binding domain at codons 270 (T/A) and 282 (C/T). The consecutive levels of p53 protein were lower in IGROV-1 than in IGROV-1/Pt cells. Following exposure to ionizing radiation or cisplatin, accumulation of the p53 protein was markedly enhanced only in the sensitive cells. Concomitantly, the expression of WAF-1 protein was strongly induced in the parental IGROV-1 cells, whereas WAF-1 protein remained undetectable in the IGROV-1/Pt 1 subline after DNA-damaging treatment. Consistent with this finding is the observation that ionizing radiation caused a different pattern of cell cycle perturbation in sensitive and resistant cells. Northern blot analysis demonstrated a marked reduction in bax mRNA levels in IGROV-1/Pt 1 cisplatin-resistant cells. Cotransfection assays with wild-type or mutant p53 expression plasmids and a reporter gene plasmid that utilized the bax gene promoter to drive transcription of chloramphenicol acetyltransferase were consistent with the role of p53 in regulation of bax expression in these cells. Taken together, these observations support a role for mutations of the p53 gene in the development of cisplatin resistance in ovarian cancer as a consequence of loss of the ability of p53 to transactivate bax, an apoptosis-inducing gene.


Assuntos
Cisplatino/farmacologia , Genes p53 , Mutação , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Proteínas Proto-Oncogênicas c-bcl-2 , Proteínas Proto-Oncogênicas/genética , Apoptose/efeitos dos fármacos , Sequência de Bases , Northern Blotting , Western Blotting , Ciclo Celular/fisiologia , Cloranfenicol O-Acetiltransferase/genética , Inibidor de Quinase Dependente de Ciclina p21 , Ciclinas/análise , Dano ao DNA , Resistencia a Medicamentos Antineoplásicos , Feminino , Expressão Gênica , Genes Reporter , Humanos , Dados de Sequência Molecular , Neoplasias Ovarianas/metabolismo , Polimorfismo Conformacional de Fita Simples , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas/biossíntese , RNA Mensageiro/metabolismo , Ativação Transcricional , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/análise , Proteína X Associada a bcl-2
4.
Cancer Res ; 56(4): 689-93, 1996 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-8630996

RESUMO

The p53 protein is a multifunctional transcriptional regulator involved in cellular response to DNA damage and has been implicated as a putative determinant of sensitivity of tumor cells to cytotoxic agents. Since the p53 gene becomes inactivated in over one-half of advanced ovarian carcinoma, in this study we have examined the relationships between p53 gene alterations, p53 immunoreactivity, and response to cisplatin-based chemotherapy in ovarian cancer patients. All patients had advanced (FIGO stage III or IV) ovarian carcinoma and, with one exception, were untreated at the time of collection of tumor specimens. After initial debulking surgery, patients received high-dose cisplatin therapy. Tumor samples were analyzed for p53 gene mutations and for p53 protein accumulation, and the findings were correlated with tumor responsiveness. Of the 33 tumors examined, p53 gene mutations were found in 20 cases, including 15 missense mutations, 2 deletions, 2 nonsense mutations, and a base substitution at splice site. Twenty tumors showed positive immunostaining for p53. Only missense mutations were associated with positive immunostaining. In addition, p53 overexpression was detected in five tumors in the absence of mutations. Most (12 of 14) of the missense mutations associated with p53 protein stabilization were found refractory to therapy, as well as tumors overexpressing wild-type p53 (4 of 5). A significant correlation has been found between p53 accumulation, type of mutation (i.e., missense mutations), and pathological response to cisplatin-based therapy. In conclusion, the present results are consistent with a role of p53 as a determinant of chemosensitivity of ovarian carcinoma.


Assuntos
Cisplatino/uso terapêutico , Genes p53 , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/genética , Mutação Puntual , Deleção de Sequência , Proteína Supressora de Tumor p53/biossíntese , Alelos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Códon , Éxons , Feminino , Humanos , Imuno-Histoquímica , Imunofenotipagem , Íntrons , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/cirurgia
5.
Cell Death Differ ; 9(12): 1352-9, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12478472

RESUMO

Mononuclear and multinuclear platinum complexes are known to induce distinct types of DNA lesions and exhibit different profiles of antitumor activity, in relation to p53 mutational status. In this study, we investigated the cellular effects of exposure to two platinum compounds (cisplatin and the multinuclear platinum complex BBR 3464), in the osteosarcoma cell line, U2-OS, carrying the wild-type p53 gene and capable of undergoing apoptosis or cell cycle arrest in response to diverse genotoxic stresses. In spite of the ability of both compounds to up-regulate p53 at cytotoxic concentrations, exposure to BBR 3464 resulted in cell cycle arrest but only cisplatin was capable of inducing significant levels of apoptosis and phosphorylation at the Ser15 residue of p53. The cisplatin-induced protein phosphorylation, not detectable in cells treated with BBR 3464, was associated with RPA phosphorylation, a specific up-regulation of Bax and down-regulation of p21(WAF1). Cells treated with BBR 3464 displayed a different cellular response with evidence of cytostasis associated with a high induction of p21(WAF1). The regulation of p21(WAF1) after cisplatin or BBR 3464 exposure required a p53 signal, as documented using stable transfectants expressing a dominant-negative form of p53 (175(his)). Taken together, these results indicate that cellular response to different genotoxic lesions (i.e. apoptosis or growth arrest) is associated with a specific recognition of DNA damage and a different p53-mediated signaling pathway. Multinuclear platinum complexes could be regarded as useful tools for investigating the p53-mediated process of cell cycle arrest in response to DNA damage.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Neoplasias/tratamento farmacológico , Compostos de Platina/farmacologia , Proteína Supressora de Tumor p53/efeitos dos fármacos , Sequência de Aminoácidos/efeitos dos fármacos , Sequência de Aminoácidos/fisiologia , Apoptose/fisiologia , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/fisiologia , Divisão Celular/efeitos dos fármacos , Divisão Celular/fisiologia , Cisplatino/farmacologia , Citotoxinas/farmacologia , Dano ao DNA/fisiologia , Humanos , Neoplasias/metabolismo , Neoplasias/fisiopatologia , Fosforilação/efeitos dos fármacos , Serina/efeitos dos fármacos , Serina/metabolismo , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/metabolismo , Proteína Supressora de Tumor p53/metabolismo
6.
Clin Cancer Res ; 3(6): 955-61, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9815771

RESUMO

Preclinical and clinical studies have documented the pharmacological interest in camptothecin derivatives in the treatment of resistant tumors. In particular, topotecan, a water-soluble derivative, exhibited promising activity in pretreated ovarian carcinoma. The present study investigated the pattern of tumor response in two human ovarian carcinoma xenografts and in their cisplatin-resistant sublines characterized by different mechanisms of drug resistance. In IGROV-1/Pt1 cells, cisplatin resistance has been ascribed to a reduced susceptibility to apoptosis as a consequence of p53 mutation and inactivation of its function. In the A2780 cisplatin-resistant subline, which retained the wild-type p53 gene status, the development of resistance has been possibly related to increased cell ability to repair drug-induced DNA damage. The in vivo results of the present study showed that topotecan could overcome the resistance in A2780/CP but not in IGROV-1/Pt1 tumor xenografts. The pattern of tumor response following in vivo topotecan treatment correlated with drug ability to induce apoptosis but not with its in vitro antiproliferative activity. The antitumor efficacy of topotecan in the four tumors reflected a different cell response to drug-induced DNA damage, as suggested by different perturbations of cell cycle progression. Indeed, only in the subline refractory to topotecan in vivo, IGROV-1/Pt1, did we observe a persistent arrest of the cells in the S-phase, resulting in a cytostatic and not a cytotoxic effect, since a low level of apoptosis was induced by the drug. In conclusion, the current results support that determination of drug-induced apoptosis is a useful predictor of tumor response to topotecan in ovarian carcinomas and suggest that p53 gene status may be a critical determinant of cell response to topoisomerase inhibitors.


Assuntos
Apoptose/efeitos dos fármacos , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/patologia , Topotecan/toxicidade , Topotecan/uso terapêutico , Animais , Sobrevivência Celular , Cisplatino/uso terapêutico , Cisplatino/toxicidade , Células Clonais , Dano ao DNA , Reparo do DNA , Resistencia a Medicamentos Antineoplásicos , Éxons , Feminino , Genes p53 , Humanos , Camundongos , Camundongos Nus , Mutação , Transplante Heterólogo , Células Tumorais Cultivadas
8.
Clin Immunol ; 92(3): 224-34, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10479527

RESUMO

The pattern of cytokine production in T cell clones derived from bronchoalveolar lavages (BAL) of active pulmonary tuberculosis (TB) patients was analyzed in clones obtained by limiting dilution procedures which expand with high efficiency either total T lymphocytes, independently of their antigen-recognition specificity, or Mycobacterium tuberculosis-specific T cells. BAL-derived clones, representative of CD4(+) cells from five patients with active TB, produced significantly higher amounts of IFN-gamma than BAL-derived CD4(+) clones from three inactive TB donors or four controls (with unrelated, noninfectious pathology). Average IL-4 and IL-10 production did not differ significantly in the three groups. Although these data suggest a predominant Th1 response to M. tuberculosis infection in the lungs, the majority of BAL-derived CD4(+) clones produced both IFN-gamma and IL-10 and the percentage of clones with this pattern of cytokine production was significantly higher in clones derived from BAL of active TB patients than from controls. Only rare clones derived from peripheral blood (PB)-derived CD45RO(+) CD4(+) T cells of both patients (nine cases) and controls (four cases) produced both IFN-gamma and IL-10; instead, the IL-10-producing clones derived from PB T cells most often also produced IL-4, displaying a typical Th2 phenotype. Higher average amounts of IFN-gamma and IL-10 were produced by BAL-derived CD8(+) clones of four active TB patients than of four controls, although the frequency of CD8(+) clones producing both IFN-gamma and IL-10 was lower than that of CD4(+) clones. The M. tuberculosis-specific BAL-derived T cell clones from three active TB patients were almost exclusively CD4(+) and produced consistently high levels of IFN-gamma often in association with IL-10, but very rarely with IL-4. Unlike the BAL-derived clones, the M. tuberculosis-specific clones derived from PB CD45RO(+) CD4(+) T cells of three different active TB patients and two healthy donors showed large individual variability in cytokine production as well as in the proportion of CD4(+), CD8(+), or TCR gamma/delta(+) clones. These results indicate the predominance of CD4(+) T cells producing both the proinflammatory cytokine IFN-gamma and the anti-inflammatory cytokine IL-10 in BAL of patients with active TB.


Assuntos
Líquido da Lavagem Broncoalveolar/química , Líquido da Lavagem Broncoalveolar/citologia , Interferon gama/biossíntese , Interleucina-10/biossíntese , Tuberculose Pulmonar/patologia , Antígenos de Bactérias/imunologia , Líquido da Lavagem Broncoalveolar/imunologia , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/metabolismo , Células Clonais/imunologia , Epitopos , Humanos , Interleucina-12/farmacologia , Antígenos Comuns de Leucócito/sangue , Leucócitos Mononucleares/química , Mycobacterium tuberculosis/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/sangue , Tuberculose Pulmonar/sangue
9.
Cell Growth Differ ; 10(7): 473-8, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10437915

RESUMO

We have previously shown that p53 mutations are associated with cisplatin resistance in ovarian carcinoma IGROV-1/Pt 1 cells. The relationship between p53 status and the development of resistance has not been completely elucidated; in particular, the biological mechanisms behind the acquired drug-resistant p53-mutant phenotype were not clearly explained. Thus, in this study, we investigated whether the p53 mutations found in IGROV-1/Pt 1 cells (270 and 282 codons) resulted from selection, under the selective pressure of the cytotoxic treatment, of a spontaneously mutant cell population preexistent in the cisplatin-sensitive parental cell line (IGROV-1) or were induced by drug (genotoxic) treatment. For this purpose, an allele-specific PCR approach was used. Primers carrying the desired mutations (T-->A codon 270, C-->T codon 282) in the 3' terminus, and the corresponding wild-type primers were used to amplify genomic DNA from the original IGROV-1 cell line used to select the mutant IGROV-1/Pt 1. To increase sensitivity, we hybridized blots of the PCRs with the radiolabeled PCR fragment from IGROV-1/Pt 1. Amplification was obtained for IGROV-1 DNA with the mutated allele-specific primers, indicating the preexistence of a mutated population in the IGROV-1 cell line. Titration experiments suggested that the frequency of the mutated alleles was <0.1%. Single-strand conformation polymorphism and allele-specific PCR analysis of the IGROV-1/Pt 0.1 cells, which are less resistant to cisplatin than IGROV-1/Pt 1 cells and which carry both mutant and wild-type p53 alleles with a wild-type predominance, suggested a progressive selection of the mutant population by cisplatin treatment. This is the first observation that indicates that a subpopulation of p53 mutant cells can occasionally be selected by cisplatin treatment. Thus, considering the susceptibility to spontaneous mutations of the p53 gene in advanced ovarian carcinoma, the selection process resulting in emergence of p53 mutant tumors is a possible origin of resistance of ovarian carcinoma to DNA-damaging agents. The survival advantage of p53 mutant cells in the presence of genotoxic agents could be related to a loss of susceptibility to p53-dependent apoptosis and to defects in checkpoints pathways, resulting in genomic instability.


Assuntos
Antineoplásicos/farmacologia , Cisplatino/farmacologia , Genes p53/genética , Neoplasias Ovarianas/genética , Alelos , Antineoplásicos/toxicidade , Cisplatino/toxicidade , Resistencia a Medicamentos Antineoplásicos , Feminino , Humanos , Mutação de Sentido Incorreto , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Reação em Cadeia da Polimerase , Células Tumorais Cultivadas
10.
Clin Exp Immunol ; 136(2): 365-72, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15086403

RESUMO

Hodgkin's lymphoma patients treated with an anti-CD25 Ricin toxin A-chain (RTA)-based Immunotoxin (RFT5.dgA) develop an immune response against the toxic moiety of the immunoconjugate. The anti-RTA antibody response of 15 patients showing different clinical features and receiving different total amounts of RFT5.dgA was therefore studied in detail, considering antibody titre, IgG and IgM content, average binding efficacy and ability to inhibit in vitro the cytotoxicity of a RTA-based Immunotoxin. No correlations were found between these parameters and the clinical features of the patients or the total amount of Immunotoxin administered. However, using a peptide scan approach we have identified a continuous epitope recognized by all patients studied, located within the stretch L161-I175 of the RTA primary sequence, close to a previously identified T-cell epitope. The ability of anti-L161-I175 antibodies to recognize folded RTA and to affect the biological activity of RTA by inhibiting RTA-IT cytotoxicity in vitro revealed that they may exert an important role in IT neutralization in vivo. Discovery of RTA immunodominant epitopes which are the target of anti-RTA immune response may lead to the development of immunomodulating strategies and to more successful treatment schedules.


Assuntos
Anticorpos/imunologia , Linfócitos B/imunologia , Doença de Hodgkin/imunologia , Epitopos Imunodominantes/imunologia , Imunotoxinas/imunologia , Ricina/imunologia , Reações Antígeno-Anticorpo , Ensaio de Imunoadsorção Enzimática/métodos , Mapeamento de Epitopos , Humanos , Imunotoxinas/uso terapêutico
11.
Electrophoresis ; 21(4): 785-91, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10733223

RESUMO

Sensitivity of single-strand conformation polymorphism (SSCP) analysis of polymerase chain reaction (PCR) products was reported to be lower in capillary zone electrophoresis (CZE) compared to conventional slab gel electrophoresis. We examined the effects of buffer ion type, pH, and temperature in an attempt to improve the mutation detectability in the SSCP-CZE mode. It was noted that, by utilizing short-chain polyacrylamide as sieving media while simultaneously lowering the temperature, there was no improvement of conformer detectability. On the contrary, there was a large increment in conformers' resolution by running samples in a lower-pH buffer system. The effects of different buffering ions and pH values were investigated. By using a new buffer system, consisting of 35 mM 2-(N-morpholino)propanesulfonic acid (MES), 30 mM tris(hydroxymethyl)aminomethane (Tris), 1 mM ethylene diaminetetraacetic acid (EDTA), pH 6.8, and keeping constant all the other conditions, such as temperature, sieving, applied voltage, capillary length, and inner diameter (ID), there was a remarkable improvement in resolution and the sensitivity became comparable to that of slab gel systems.


Assuntos
Genes p53 , Reação em Cadeia da Polimerase/métodos , Polimorfismo Conformacional de Fita Simples , Soluções Tampão , Primers do DNA , DNA de Cadeia Simples/isolamento & purificação , Eletroforese Capilar/métodos , Triagem de Portadores Genéticos/métodos , Humanos , Concentração de Íons de Hidrogênio , Sensibilidade e Especificidade
12.
Electrophoresis ; 18(15): 2921-7, 1997 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9504831

RESUMO

Genetic instability is a typical feature of tumor cells. This evidence has stimulated the development of rapid methods for detection of gene mutations. A new, improved protocol for denaturing gradient gel electrophoresis (DGGE), to screen for point mutations in genomic DNA, is reported: double gradient (DG) DGGE. In this technique, to the primary, denaturing gradient (typically 30-80% or 40-80% urea/formamide) a secondary gradient, colinear with the first, is superimposed: a porosity gradient (typically 6.5-12% polyacrylamide). The secondary gradient acts by recompacting smeared and diffuse bands of heteroduplexes, which are often indistinguishable from background fluorescence, and by augmenting the resolution between closely spaced homoduplex zones. This allows proper densitometric quantitation of the ratio of the two homoduplex bands. The reliability of this technique has been documented by detection of a number of mutations in exons 6 and 8 of the p53 gene which had escaped revelation by single-strand conformational polymorphism (SSCP) analysis. Additionally, the precise assessment of ratio of the doublet of homoduplex bands has allowed quantitation of the extent of p53 mutation in a mixed cell population extracted from a tumor specimen.


Assuntos
Eletroforese em Gel de Poliacrilamida/métodos , Genes p53 , Mutação Puntual , Etídio , Feminino , Corantes Fluorescentes , Genoma Humano , Humanos , Desnaturação de Ácido Nucleico , Neoplasias Ovarianas/genética , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples , Porosidade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Células Tumorais Cultivadas
13.
Clin Chem ; 45(1): 35-40, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9895335

RESUMO

Among established techniques for the identification of either known or new mutations, denaturing gradient gel electrophoresis (DGGE) is one of the most effective. However, conventional DGGE is affected by major drawbacks that limit its routine application: the different denaturant gradient ranges and migration times required for different DNA fragments. We developed a modified version of DGGE for high-throughput mutational analysis, double gradient DGGE (DG-DGGE), by superimposing a porous gradient over the denaturant gradient, which maintains the zone-sharpening effect even during lengthy analyses. Because of this innovation, DG-DGGE achieves the double goals of retaining full effectiveness in the detection of mutations while allowing identical run time conditions for all fragments analyzed. Here we use retrospective analysis of a large number of well-characterized mutations and polymorphisms, spanning all predicted melting domains and the whole genomic sequence of three different genes--the cystic fibrosis transmembrane conductance regulator (CFTR), the beta-globin, and the p53 genes--to demonstrate that DG-DGGE may be applied to the rapid scanning of any sequence variation.


Assuntos
Análise Mutacional de DNA/métodos , DNA/genética , Eletroforese/métodos , Desnaturação de Ácido Nucleico , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Globinas/genética , Humanos , Mutação , Polimorfismo Genético , Reprodutibilidade dos Testes , Proteína Supressora de Tumor p53/genética
14.
Clin Chem Lab Med ; 36(12): 959-61, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9915229

RESUMO

Denaturing gradient gel electrophoresis displays the highest detection rate among mutation scanning methods. In classical denaturing gradient gel electrophoresis the denaturant gradient range and migration times vary for every amplicon to be scanned, greatly affecting the routine application of the method. As an alternative, we developed double gradient denaturing gradient gel electrophoresis where a gradient of pore size is superimposed over the denaturing one, allowing maintenance of the zone-sharpening effect even over prolonged time runs, and adoption of identical run time conditions for all fragments analyzed. Here double gradient denaturing gradient gel electrophoresis has been applied to the analysis of a number of point mutations and polymorphisms located in several exons of three different genes, the cystic fibrosis transmembrane conductance regulator, the beta-globin and the p53 genes.


Assuntos
DNA/genética , Eletroforese em Gel de Poliacrilamida/métodos , Mutação Puntual , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Genes p53 , Globinas/genética , Humanos
15.
Apoptosis ; 2(6): 540-8, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-14646525

RESUMO

Since apoptosis is the primary mode of cell death induced by cisplatin, the role of apoptosis and apoptosis-related gene products in cisplatin resistance was investigated in four human cisplatin-resistant cell lines of different tumour type. A common feature of the resistant sublines was a reduced susceptibility to drug-induced apoptosis compared to parental sensitive lines. Loss of wild-type p53 function was not a general event associated with the development of drug resistance. An increased bcl-2 expression was found in resistant cells characterized by mutant p53 (A431/Pt and IGROV-1/Pt), whereas in osteosarcoma (U2-OS/Pt) and in ovarian carcinoma (A2780/CP) cells with wild-type p53, bcl-2 levels were markedly reduced. U2-OS/Pt cells had a 16-fold increase in the level of Bcl-xL protein. Stable transfection of U2-OS cells with bcl-xL cDNA conferred a low level of drug resistance to cisplatin, suggesting that overexpression of this gene contributes to the cisplatin-resistant phenotype of this osteosarcoma cell system. In conclusion, these observations suggest a variable contribution of apoptosis-related genes to cisplatin resistance depending on the biological background of the cell system and presumably reflecting different pathways of apoptosis.

16.
Br J Cancer ; 80(12): 1912-9, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10471039

RESUMO

Multinuclear platinum compounds were rationally designed to bind to DNA in a different manner from that of cisplatin and its mononuclear analogues. A triplatinum compound of the series (BBR 3464) was selected for preclinical development, since, in spite of its charged nature, it was very potent as cytotoxic agent and effective against cisplatin-resistant tumour cells. Anti-tumour efficacy studies were performed in a panel of human tumour xenografts refractory or poorly responsive to cisplatin. The novel platinum compound exhibited efficacy in all tested tumours and an impressive efficacy (including complete tumour regressions) was displayed in two lung carcinoma models, CaLu-3 and POCS. Surprisingly, BBR 3464 showed a superior activity against p53-mutant tumours as compared to those carrying the wild-type gene. The involvement of p53 in tumour response was investigated in an osteosarcoma cell line, SAOS, which is null for p53 and is highly sensitive to BBR 3464, and in the same cells following introduction of the wild-type p53 gene. Thus the pattern of cellular response was investigated in a panel of human tumour cells with a different p53 gene status. The results showed that the transfer of functional p53 resulted in a marked (tenfold) reduction of cellular chemosensitivity to the multinuclear platinum complex but in a moderate sensitization to cisplatin. In addition, in contrast to cisplatin, the triplatinum complex was very effective as an inducer of apoptosis in a lung carcinoma cell line carrying mutant p53. The peculiar pattern of anti-tumour activity of the triplatinum complex and its ability to induce p53-independent cell death may have relevant pharmacological implications, since p53, a critical protein involved in DNA repair and induction of apoptosis by conventional DNA-damaging agents, is defective in several human tumours. We suggest that the peculiar DNA binding properties of the triplatinum complex may contribute to the striking profile of anti-tumour efficacy. Taken together, the available information supports that anti-tumour activity of the novel compound is mediated by a mechanism different from that of conventional platinum complexes, and compounds of this series could represent a new class of promising anti-tumour agents.


Assuntos
Antineoplásicos/uso terapêutico , Cisplatino/uso terapêutico , Resistencia a Medicamentos Antineoplásicos , Genes p53 , Mutação , Neoplasias/tratamento farmacológico , Compostos Organoplatínicos/uso terapêutico , Animais , Ciclo Celular/efeitos dos fármacos , Feminino , Humanos , Masculino , Camundongos , Camundongos Nus , Modelos Moleculares , Conformação Molecular , Neoplasias/genética , Neoplasias/patologia , Compostos Organoplatínicos/química , Compostos Organoplatínicos/toxicidade , Osteossarcoma/tratamento farmacológico , Osteossarcoma/genética , Osteossarcoma/patologia , Polimorfismo Conformacional de Fita Simples , Transplante Heterólogo
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