RESUMO
Background: Leukemia is a neoplasm with high incidence and mortality rates. Mitotic death has been observed in tumor cells treated with chemotherapeutic agents. Ras family proteins participate in the transduction of signals involved in different processes, such as proliferation, differentiation, survival, and paradoxically, initiation of cell death. Methods: This study investigated the effect of H-Ras expression on human T-cell acute lymphoblastic leukemia MOLT-4 cells. Cells were electroporated with either wild-type (Raswt) or oncogenic mutant in codon 12 exon 1 (Rasmut) versions of H-Ras gene and stained for morphological analysis. Cell viability was assessed using trypan blue staining and cell cycle analysis using flow cytometry. H-Ras gene expression was determined using quantitative real-time reverse transcription polymerase chain reaction. The t, ANOVA, and Scheffe tests were used for statistical analysis. Results: Human T-cell acute lymphoblastic leukemia MOLT-4 cells showed nuclear fragmentation and presence of multiple nuclei and micronuclei after transfection with either wt or mutant H-Ras genes. Cell cycle analysis revealed a statistically significant increase in cells in the S phase when transfected with either wt (83.67%, P<0.0005) or mutated (81.79%, P<0.0001) H-Ras genes. Although similar effects for both versions of H-Ras were found, cells transfected with the mutated version died at 120 h of mitotic catastrophe. Conclusion: Transfection of human T-cell acute lymphoblastic leukemia MOLT-4 cells with either normal or mutated H-Ras genes induced alterations in morphology, arrest in the S phase, and death by mitotic catastrophe.
RESUMO
Introducción: metformina es un medicamento antidiabético evaluado en varios modelos in vitro e in vivo de cáncer ya que es capaz de incrementar la proteincinasa activada por adenosin monofosfato y bloquear las vías de señalización tumoral. Objetivo: evaluar los efectos antitumorales de metformina en línea celular MOLT-4 en pacientes bajo tratamiento de inducción a la remisión. Materiales y métodos: fase in vitro: ensayo en línea celular MOLT-4 adicionando metformina 40 mM evaluando la viabilidad y ciclo celular mediante citometría de flujo. Fase clínica: Estudio de casos y controles en pacientes portadores de leucemia linfoblástica aguda de novo, adicionando metformina 850 mg cada ocho horas en etapa de pretratamiento e inducción a la remisión, contra el registro histórico del protocolo institucional HGMLAL07. Para el análisis estadístico se utilizó el test de chi-cuadrado, estudio multivariado para factores de riesgo y evaluación del efecto sobre la remisión mediante Odds Ratio. Resultados: ensayo celular: meformina inhibió la viabilidad celular a las 120 horas, reduciendo el porcentaje de células en fase S. Estudio clínico: en un total de 151 pacientes, el 29,1% correspondieron al brazo de metformina. La mayor tasa de respuesta favorable a esteroides como de remisiones completas se encontraron en los pacientes que recibieron metformina (59,1% versus 26,2% y 81,8% versus 57,9%) con significancia estadística (p= 0.000* y 0,006 95% IC). Conclusiones: la adición de metformina a la quimioterapia incremento la respuesta favorable a esteroides y las tasas de remisiones completas. In vitro, y semejante a otros modelos, metformina arresta a las células en G0 /G1 , induciendo una disminución en la viabilidad celular.
Introduction: metformin, antidiabetic drug evaluated in several in vitro and in vivo cancer models, is able of increasing the adenosine monophosphate activated protein kinase and block tumor signaling pathways. Objetive: to evaluate the antitumor effects of metformin in MOLT-4 cell line and in patients under treatment for remission induction. Materials and methods: in vitro phase: essay in MOLT-4 cell line adding metformin 40 mM evaluating the viability and cell cycle by flow cytometry. Clinic phase: Case-control study in patients with de novo acute lymphoblastic leukemia, adding metformin three time a day on pretreatment stage and remission induction, against the historical record of the institutional protocol HGMLAL07. Statistical analysis: chi-square analysis, multivariate analysis for risk factors and evaluation of the effect over the remission by Odds ratio. Results: celular assay: metformina inhibited cell viability at 120 hours reducing the percentage of cells in phase S. Clinical assay: 151 patients were studied, 29.1% on metformina arm. The highest rate of good steroid response and complete remissions were found in patients who received metformin (59,1% versus 26,2% and 81,8% vs 57,9%) statistically significant (p= 0.000* and 0.006, 95% IC). Conclusions: the addition of metformin to chemotherapy increased the good steroids response to steroids and rates of complete remissions. In vitro, and similar to other models, metformin arrest cells in G0 /G1 , inducing a decrease in cell viability.