ABSTRACT
RESUMEN: La piel es el órgano más extenso en el ser humano, su integridad representa protección contra diferentes agentes químicos, biológicos y mecánicos. Las lesiones ocasionadas en este tejido se resuelven mediante la formación de una cicatriz, sin embargo, diferentes alteraciones moleculares pueden sobre estimular este proceso, lo que conlleva a la formación de cicatrices aberrantes (hipertrófica o queloide). El tratamiento más recomendado para este tipo de lesiones es la aplicación intralesional del acetónido de triamcinolona (AT) y por otro lado, la dehidroepiandrosterona (DHEA) es una pro-hormona que posee una gran variedad de efectos biológicos como: regulación de la síntesis de fibras de colágeno, protección celular, propiedades antitumorales, antiinflamatorias y antioxidante. En este trabajo, se estudió la combinación de AT-DHEA sobre la proliferación y muerte celular en la línea celular de fibroblastos 3T3-L1. Los resultados mostraron que la AT a 100 M y la DHEA a 1000 M inhiben la proliferación en un 50 y 40% respectivamente. La combinación de AT-DHEA (10000-10 M) inhibe la proliferación celular e inducen muerte celular programada, entonces esta combinación pudiera utilizarse en cicatrices hipertróficas o queloides para su eliminación.
ABSTRACT: The skin in the human is the largest organ, his integrity represents protection against various chemical, biological and mechanical agents. The injuries in this tissue are solved by forming a scar, however, different molecular alterations may overstimulate this process, leading to the formation of aberrant scars (hypertrophic or keloid). The most recommended treatment for such injuries is the intralesional application of triamcinolone acetonide (TA) and on the other hand, dehydroepiandrosterone (DHEA) is a pro-hormone that has a wide variety of biological effects such as regulation of the synthesis of collagen fibers, cell protection, anti-tumor properties, anti-inflammatory and antioxidant. In this paper, the combination of AT-DHEA on proliferation and cell death in fibroblast cell line 3T3-L1 was studied. The results showed that the AT 100 and 1000 M DHEA to inhibit proliferation by 50 and 40% respectively. The combination of AT-DHEA (10000-10 M) inhibits cell proliferation and induce programmed cell death, so this combination could be used in hypertrophic or keloid scars for disposal.
ABSTRACT
Phosphatidylinositol (PI) 3-kinase plays an important role in transducing the signals of various growth factor receptors. However, the regulatory mechanism of PI3-kinase activity by these growth factor receptors is not completely understood. Therefore, we attempted to clarify the regulatory mechanism of PI3-kinase using insulin and 3T3 L1 fibroblasts. Our results showed that insulin stimulated PI3-kinase activity seven-fold and concomitantly phosphorylated a p85 subunit at the tyrosine residue. However, this tyrosine phosphorylation was not significant in the activation of PI3-kinase as the PI3-kinase pulled down by the overexpressed GST-p85 fusion protein showed as high an activity as the immunoprecipitated one. The p110 subunit was phosphorylated at both serine and tyrosine residues without insulin treatment. Since the phosphorylation state was not changed by insulin. The results suggested that phosphorylation of the p110 subunit does not control PI3-kinase activity. Finally, it was shown that the insulin receptor substrate-1 (IRS-1) binding to PI3-kinase was not sufficient for full activation because the amount of IRS-1 pulled down by the GST-p85 fusion protein reached almost maximum, after incubation with insulin-treated cell lysates for 20 min, whereas PI3-kinase activity reached its maximum only after incubation for 5 h. All results suggest that the phosphorylation of p85 subunit at tyrosine residues and phosphorylation of p110 subunit at tyrosine or serine residues are not functionally significant in the regulation of PI3-kinase activity. They also suggest that P13-kinase is needed to bind to other protein(s) as well as the insulin receptor substrate-1 for full activation.