Oxidase enzyme genes are differentially expressed during Acanthamoeba castellanii encystment.

Acanthamoeba castellanii, a ubiquitous protozoan, is responsible for significant diseases such as Acanthamoeba keratitis and granulomatous amoebic encephalitis. A crucial survival strategy of A. castellanii involves the formation of highly resistant cysts during adverse conditions. This study delves into the cellular processes underpinning encystment, focusing on gene expression changes related to reactive oxygen species (ROS) balance, with a particular emphasis on mitochondrial processes. Our findings reveal a dynamic response within the mitochondria during encystment, with the downregulation of key enzymes involved in oxidative phosphorylation (COX, AOX, and NADHalt) during the initial 48 h, followed by their overexpression at 72 h. This orchestrated response likely creates a pro-oxidative environment, facilitating encystment. Analysis of other ROS processing enzymes across the cell reveals differential expression patterns. Notably, antioxidant enzymes, such as catalases, glutaredoxins, glutathione S-transferases, peroxiredoxins, and thioredoxins, mirror the mitochondrial trend of downregulation followed by upregulation. Additionally, glycolysis and gluconeogenesis are downregulated during the early stages in order to potentially balance the metabolic requirement of the cyst. Our study underscores the importance of ROS regulation in Acanthamoeba encystment. Understanding these mechanisms offers insights into infection control and identifies potential therapeutic targets. This work contributes to unraveling the complex biology of A. castellanii and may aid in combatting Acanthamoeba-related infections. Further research into ROS and oxidase enzymes is warranted, given the organism's remarkable respiratory versatility.

Estradiol-Induced Epithelial to Mesenchymal Transition and Migration Are Inhibited by Blocking c-Src Kinase in Breast Cancer Cell Lines.

PURPOSE: The epithelial-to-mesenchymal transition (EMT) is the main event that favors cell migration and metastasis in breast cancer. Previously, we demonstrated that 1 nM estradiol (E2) promotes EMT, induced by c-Src kinase, causing changes in the localization of proteins that compose the tight junction (TJ) and adherens junction (AJ). METHODS: The present work highlights the central role of c-Src in the initiation of metastasis, induced by E2, through increasing the ability of MCF-7 and T47-D cells, which express estrogen receptor alpha (ERα), to migrate and invade before they become metastatic. RESULTS: Treatment with E2 can activate two signaling pathways, the first one by the phosphorylated c-Src (p-Src) which forms the p-Src/E-cadherin complex. This phenomenon was completely prevented by incubation with a selective inhibitor of c-Src (5 µM PP2). p-Src then promotes the downregulation of E-cadherin and occludin, which are epithelial phenotype marker proteins of the AJ and TJ, respectively. In the second pathway, E2 binds to ERα, creating a complex that translocates to the nucleus, inducing the synthesis of SNAIL1 and N-cadherin proteins, markers of the mesenchymal phenotype. Both processes increased the migratory and invasive capacities of both cell lines. CONCLUSION: The present study demonstrate that E2 enhance EMT and migration, through c-Src activation, in human breast cancer cells that express ERα and become potential therapeutic targets.

Non-Genomic Actions of Estrogens on the DNA Repair Pathways Are Associated With Chemotherapy Resistance in Breast Cancer.

Estrogens have been implicated in the etiology of breast cancer for a long time. It has been stated that long-term exposure to estrogens is associated with a higher incidence of breast cancer, since estradiol (E2) stimulates breast cell growth; however, its effect on DNA damage/repair is only starting to be investigated. Recent studies have documented that estrogens are able to modify the DNA damage response (DDR) and DNA repair mechanisms. On the other hand, it has been proposed that DDR machinery can be altered by estrogen signaling pathways, that can be related to cancer progression and chemoresistance. We have demonstrated that E2 promotes c-Src activation and breast cancer cell motility, through a non-genomic pathway. This review discusses scientific evidence supporting this non-genomic mechanism where estrogen modifies the DNA repair pathways, and its relationship to potential causes of chemoresistance.