Emetine produce Entamoeba histolytica Death by Inducing a Programmed Cell Death

A Drug Screening Revealed Novel Potential Agents against Malignant Pleural Mesothelioma

The lack of effective therapies remains one of the main challenges for malignant pleural mesothelioma (MPM). In this perspective, drug repositioning could accelerate the identification of novel treatments. We screened 1170 FDA-approved drugs on a SV40-immortalized mesothelial (MeT-5A) and five MPM (Mero-14, Mero-25, IST-Mes2, NCI-H28 and MSTO-211H) cell lines. Biological assays were carried out for 41 drugs, showing the highest cytotoxicity and for whom there were a complete lack of published literature in MPM. Cytotoxicity and caspase activation were evaluated with commercially available kits and cell proliferation was assayed using MTT assay and by clonogenic activity with standard protocols. Moreover, the five most effective drugs were further evaluated on patient-derived primary MPM cell lines. The most active molecules were cephalomannine, ouabain, alexidine, thonzonium bromide, and emetine. Except for alexidine, these drugs inhibited the clonogenic ability and caspase activation in all cancer lines tested. The proliferation was inhibited also on an extended panel of cell lines, including primary MPM cells. Thus, we suggest that cephalomannine, ouabain, thonzonium bromide, and emetine could represent novel candidates to be repurposed for improving the arsenal of therapeutic weapons in the fight against MPM.

Emetine inhibits migration and invasion of human non-small-cell lung cancer cells via regulation of ERK and p38 signaling pathways

Emetine is a natural compound originated from ipecac roots. It was commonly used as anti-protozoal and vomiting agent. The apoptosis-inducing effect of emetine makes it considered as a potential anti-cancer agent for various human cancers. Here in this study, we report that emetine inhibits migration and invasion of human non-small-cell lung cancer (NSCLC) cells. Modulation of three major mitogen-activated protein kinases (MAPKs), ERK, p38 and JNK, is well known to be involved in regulation of matrix metalloproteinases (MMPs), which are essential in tissue remodeling and extracellular matrix (ECM) degradation, for cancer cells to spread out from the origin of tumorigenesis. Emetine regulates two major MAPKs, p38 and ERK. Differential inhibition/stimulation of ERK and p38 induced differential suppressions of β-catenin and c-myc transcription factors. This leads to the selective down-regulation of MMP-2 and MMP-9, two major gelatinases which can degrade ECM components, and RECK, a negative regulator of MMP-9.

In vivo programmed cell death of Entamoeba histolytica trophozoites in a hamster model of amoebic liver abscess

Entamoeba histolytica trophozoites can induce host cell apoptosis, which correlates with the virulence of the parasite. This phenomenon has been seen during the resolution of an inflammatory response and the survival of the parasites. Other studies have shown that E. histolytica trophozoites undergo programmed cell death (PCD) in vitro, but how this process occurs within the mammalian host cell remains unclear. Here, we studied the PCD of E. histolytica trophozoites as part of an in vivo event related to the inflammatory reaction and the host-parasite interaction. Morphological study of amoebic liver abscesses showed only a few E. histolytica trophozoites with peroxidase-positive nuclei identified by terminal deoxynucleotidyltransferase enzyme-mediated dUTP nick end labelling (TUNEL). To better understand PCD following the interaction between amoebae and inflammatory cells, we designed a novel in vivo model using a dialysis bag containing E. histolytica trophozoites, which was surgically placed inside the peritoneal cavity of a hamster and left to interact with the host's exudate components. Amoebae collected from bags were then examined by TUNEL assay, fluorescence-activated cell sorting (FACS) and transmission electron microscopy. Nuclear condensation and DNA fragmentation of E. histolytica trophozoites were observed after exposure to peritoneal exudates, which were mainly composed of neutrophils and macrophages. Our results suggest that production of nitric oxide by inflammatory cells could be involved in PCD of trophozoites. In this modified in vivo system, PCD appears to play a prominent role in the host-parasite interaction and parasite cell death.