Dataset Information

Amoebapores and NK-lysin, members of a class of structurally distinct antimicrobial and cytolytic peptides from protozoa and mammals: a comparative functional analysis.

ABSTRACT: Amoebapores, the pore-forming polypeptides of the protozoan parasite Entamoeba histolytica, and NK-lysin, an effector molecule of porcine NK (natural killer) and cytotoxic T cells, belong to the same protein family, the saposin-like proteins. As both types of protein are implicated in the killing of microbes in vivo, it appears that phylogenetically diverse organisms such as amoebae and mammals use similar effector molecules to fulfil a comparable task. However, structural features have led to the assumption that the proteins display their activities according to different modes of action. To address this question, we analysed the antibacterial, cytotoxic and pore-forming activities of these proteins in parallel and in comprehensive detail. Interestingly, the comparison of activities revealed significant differences. Whereas NK-lysin, recombinantly expressed, is efficient at a broad range of pH values, the amoebapores exhibited a pronounced pH dependence of all their activities, with markedly decreased activity at pH values above 6. Moreover, increasing salinity affects amoebapores more drastically than NK-lysin. All of the proteins compared were found to be potently active against Gram-positive bacteria, but only NK-lysin was equally efficient against Gram-negative bacteria. However, the amoebapores displayed five times higher pore-forming activity than NK-lysin, which is in accordance with the more hydrophobic character of the amoebapores compared with the essentially cationic NK-lysin.

SUBMITTER: Bruhn H

PROVIDER: S-EPMC1223731 | biostudies-other | 2003 Nov

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:IntroductionCationic antimicrobial peptides (CAPs) defend against microbial pathogens; however, certain CAPs also exhibit anticancer activity. The purpose of this investigation was to determine the effect of the pleurocidin-family CAPs, NRC-03 and NRC-07, on breast cancer cells.MethodsMTT (3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide) and acid phosphatase cell-viability assays were used to assess NRC-03- and NRC-07-mediated killing of breast carcinoma cells. Erythrocyte lysis was determined with hemolysis assay. NRC-03 and NRC-07 binding to breast cancer cells and normal fibroblasts was assessed with fluorescence microscopy by using biotinylated-NRC-03 and -NRC-07. Lactate dehydrogenase-release assays and scanning electron microscopy were used to evaluate the effect of NRC-03 and NRC-07 on the cell membrane. Flow-cytometric analysis of 3,3'-dihexyloxacarbocyanine iodide- and dihydroethidium-stained breast cancer cells was used to evaluate the effects of NRC-03 and NRC-07 on mitochondrial membrane integrity and reactive oxygen species (ROS) production, respectively. Tumoricidal activity of NRC-03 and NRC-07 was evaluated in NOD SCID mice bearing breast cancer xenografts.ResultsNRC-03 and NRC-07 killed breast cancer cells, including drug-resistant variants, and human mammary epithelial cells but showed little or no lysis of human dermal fibroblasts, umbilical vein endothelial cells, or erythrocytes. Sublethal doses of NRC-03 and, to a lesser extent, NRC-07 significantly reduced the median effective concentration (EC50) of cisplatin for breast cancer cells. NRC-03 and NRC-07 bound to breast cancer cells but not fibroblasts, suggesting that killing required peptide binding to target cells. NRC-03- and NRC-07-mediated killing of breast cancer cells correlated with expression of several different anionic cell-surface molecules, suggesting that NRC-03 and NRC-07 bind to a variety of negatively-charged cell-surface molecules. NRC-03 and NRC-07 also caused significant and irreversible cell-membrane damage in breast cancer cells but not in fibroblasts. NRC-03- and NRC-07-mediated cell death involved, but did not require, mitochondrial membrane damage and ROS production. Importantly, intratumoral administration of NRC-03 and NRC-07 killed breast cancer cells grown as xenografts in NOD SCID mice.ConclusionsThese findings warrant the development of stable and targeted forms of NRC-03 and/or NRC-07 that might be used alone or in combination with conventional chemotherapeutic drugs for the treatment of breast cancer.

Dataset Information

Amoebapores and NK-lysin, members of a class of structurally distinct antimicrobial and cytolytic peptides from protozoa and mammals: a comparative functional analysis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets