RESUMO
BACKGROUND: The p53 codon 72 polymorphism, which results in either an arginine or proline residue, plays a different role in vitro and in vivo in cell survival and drug resistance. We verified, in vitro, the impact of the arginine allele on cell survival under normoxia and hypoxia, and investigated in vivo the role of p53 codon 72 arginine homozygosity in the clinical outcome of advanced breast cancer patients. METHODS: Tumors at advanced stages grow in vivo in a hypoxic environment, and we mimicked such conditions in vitro using p53 null breast cancer cells transfected with either the arginine or proline allele. We also analyzed in vivo the p53 codon 72 genotype status of advanced breast cancer patients. RESULTS: In vitro transfection of the arginine allele induced higher cell death under normoxia, whereas cell death was greater in proline-transfected cells under hypoxia. The arginine allele upregulated BCRP-I, a hypoxia response gene, which increases drug resistance. Metastatic breast cancer patients homozygous for arginine had a significantly shorter time to progression and overall survival than those with heterozygous arginine/proline tumors. CONCLUSION: We provide a molecular explanation for the association of the arginine allele with tumor aggressiveness and treatment resistance in advanced breast cancer.
Assuntos
Alelos , Arginina/genética , Neoplasias da Mama/genética , Códon/genética , Polimorfismo de Nucleotídeo Único/genética , Proteína Supressora de Tumor p53/genética , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/genética , Adulto , Idoso , Neoplasias da Mama/patologia , Neoplasias da Mama/fisiopatologia , Linhagem Celular Tumoral , Sobrevivência Celular/fisiologia , Progressão da Doença , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Humanos , Hipóxia/fisiopatologia , Estimativa de Kaplan-Meier , Pessoa de Meia-Idade , Proteínas de Neoplasias/genética , Prolina/genética , Transfecção , Regulação para CimaRESUMO
Nitric oxide-releasing non steroidal anti-inflammatory drugs (NO-NSAIDs) are a promising class of compounds that cause cell cycle perturbations and induce apoptosis in cell lines from different tumors. We investigated the activity of a recently developed NO-NSAID (NCX 4040) in bladder cancer cell lines (HT1376 and MCR). Cells were treated with different drug concentrations for different exposure times. Cytostatic and cytocidal activity was tested by SRB assay and apoptosis was evaluated by TUNEL analysis, ANNEXIN V assay and fluorescence microscopy. To further investigate the cell death-inducing mechanisms of NCX 4040, we analyzed gp-170, caspase expression and mitochondrial membrane potential (Delta Psi) depolarization. NCX 4040 showed a striking cytocidal activity in both cell lines, reaching LC(50) at a 10-microM and 50-microM concentrations in HT1376 and in MCR cells, respectively, after an exposure of only 6 h followed by an 18-h washout. Apoptosis was triggered in up to 90% of cells and was associated with active caspase-3 expression and Delta Psi depolarization in both cell lines after a 6-h exposure. In conclusion, NCX 4040, which probably causes apoptosis via a mitochondrial-dependent mechanism, could prove to be a useful agent for improving bladder cancer treatment.
Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Apoptose/fisiologia , Aspirina/análogos & derivados , Óxido Nítrico/metabolismo , Nitrocompostos/farmacologia , Neoplasias da Bexiga Urinária/tratamento farmacológico , Anti-Inflamatórios não Esteroides/uso terapêutico , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Aspirina/farmacologia , Aspirina/uso terapêutico , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Marcação In Situ das Extremidades Cortadas , Potenciais da Membrana/efeitos dos fármacos , Nitrocompostos/uso terapêutico , Salicilatos/farmacologia , Salicilatos/uso terapêuticoRESUMO
High expression of the epidermal growth factor receptor (EGFR) family confers a growth advantage on malignant cells in various tumor types. Most pancreatic cancers express EGFR, which seems to play an important role in the acquisition of aggressive clinical behaviour and in tumor invasion. Iressa (ZD1839), a quinazoline tyrosine kinase inhibitor selective for the EGF receptor, has shown good anti-tumor activity in both preclinical and clinical studies. Using two pancreatic cancer cell lines that express different EGFR and ErbB-2 levels, we analyzed the activity of Iressa and evaluated its modulation effect on four conventional cytotoxic drugs: gemcitabine, oxaliplatin, docetaxel and SN38. Iressa was tested at scalar doses up to the plasma peak level concentration and showed a similar weak cytostatic effect in both cell lines. Conversely, an additive or weak synergistic effect was observed when the drug was administered simultaneously with or following cytotoxic drugs. Our data show that Iressa has only a weak activity at doses within the plasmatic peak concentration and that its effect is independent of EGFR and p42/p44 expression and phosphorylation levels. This is in agreement with recent literature data that attribute an essential role to a specific EGFR mutation in mediating response to Iressa. This mutation was absent in both pancreatic cell lines tested.