Caracterización del efecto anticanceroso e identificación de dianas moleculares de principios activos procedentes de "Serratia marcescens"

Abstract

This works shows the characterization of the anticancerous effect and the identification of the molecular targets of bioactive molecules from the bacteria Serratia marcescens. In particular, we have studied the anticancerous ability in vitro and ex vivo of the cyclodepsipeptide serratamolide (AT514) in several cancerous and non-cancerous cells from different origin. We have also evaluated the in vivo toxicity of AT514. Regarding the tripirrol prodigiosin, we have extended our knowledge about its anticancerous ability evaluating breast, lung and neuroblastoma cancer cells, including some multidrug resistant cancer cell lines. Both molecules induce citostatic or citotoxic effects depending on the cellular type, dose and drug exposure time, with more potent effects in cancerous cells. We have also studied the mechanism of action that they activate in order to trigger their anticancerous effect. AT514 interacts with the prosurvival pathway PI3K/AKT/NF-¿ÊB, inducing dephosphorilation of the kinase AKT and inhibiting the transcriptional activity of NF-¿ÊB. Through the analysis of variations in gene and protein expression after treatment with prodigiosin, we have identified several target genes. Among the proteins that significantly modified their expression, we found some related to cellular detoxification, DNA repair and structural proteins. In the macroarrays experiments, we identified 37 genes that significantly modulated their expression, being the antitumorigenic gene NAG-1 the most modulated one. After prodigiosin treatment, GSK-3¿Â induced the expression of this gene. This kinase has a key role in the effects provoked by this drug as it induced also death receptor 4 and 5 (DR-4, -5) and cell cycle inhibitor p21 gene expression. We have also observed that activation of the citokine TGF-¿Â pathway is necessary for p21 induction. Moreover, the anticancerous effect of both substances is independent of the tumor supressor gene p53 functional status, advantageous trait as it is mutated in the vast majority of human tumours. The results obtained show in detail the molecular pathways that are activated by two novel anticancerous agents, pointing them as potential chemotherapeutic agents. "