Relocalización de factores de transcripción en células U118

Abstract

[eng] The eukaryotic cell contains two main internal compartments; the cytoplasm and the nucleus, each bounded by cell membranes. The cytoplasm is isolated from the extracellular medium by an outer or plasma membrane and the nucleus is separated from the cytoplasm by a nuclear membrane. These cell membranes besides physically separating both compartments additionally present functions of vital importance to the cell such as the regulation of their response to external signals, in order to adapt to these conditions by activating certain cellular signaling pathways, allowing the cell to stimulate or inactivate the synthesis of certain proteins involved in cell proliferation, cell cycle and apoptosis. In cancer, these responses from the cell to external signals are affected, causing aberrant signaling pathways and consequently the stimulation of the continuous synthesis of certain proteins, which leads to uncontrolled growth of the cell. The altered signaling pathways in tumor cells have been attributed in several studies to changes or imbalances in the lipid composition of the plasma membrane. It exists a new therapeutic strategy denominated Lipid Membrane Therapy (TLM) which is dedicated to the design of new molecules that modify altered membrane lipids in tumor cells, thereby regulating the activity of proteins involved in signal transduction. 2OHOA modifies the lipid composition of the plasma membrane of the cell causing changes in the activation and localization of proteins involved in signaling proliferation and differentiation, showing antiproliferative effects. In this study, from 2OHOA-treated glioblastoma U118 cells at different time intervals (24h and 48h) and compared to an untreated control, we sought to determine whether changes that have been described in the plasma membrane of tumor cells can be occurring at the nuclear membrane level and whether these could have an effect on nucleo-cytoplasmic trafficking of transcription factors whose levels are affected by treatment with 2OHOA. For this, through cell fractionation, the two main fractions of the cell are separated; cytoplasmic and nuclear, and to analyze the situation of certain transcriptional factors responsible for regulating gene expression in the nucleus from cytoplasmic signals such as NICD, c-Jun, E2F -1, β-catenin and FOXO1 (Forkhead Box O1), in addition to the separation of the different lipid species by thin layer chromatography (HP-TLC) and to evaluate possible lipid changes in the nuclear membrane caused by 2OHOA in glioblastoma cells. The results obtained from the lipid species show a tendency to be altered after the treatment with 2OHOA in the different cell fractions, and in a significant way the transcription factors are influenced in the nucleuscytoplasmic traffic affecting possible cell, signaling pathways related to apoptosis, cell cycle progression and differentiation, among others. Thus, treatment with 2OHOA in U118 glioblastoma cells can induce antiproliferative effects.