Cyclodextrin enhances spermicidal effects of magainin-2-amide

On the selectivity and efficacy of defense peptides with respect to cancer cells

“…Cholesterol is a major sterol of eukaryotic cell membranes, and it has been previously suggested that this compound may generally offer protection to eukaryotic membranes from the lytic action of some α‐ACPs by changing membrane fluidity, and thereby reducing the ability of these peptides to partition into the membrane . Consistent with this suggestion, it was found that increasing levels of membrane cholesterol inhibited the lytic ability of a number of α‐ACPs toward membranes of nonmalignant eukaryotic cells and lipid mimics of these membranes, including cecropins, and magainins which are amphibian α‐ACP AO peptides . Based on these and other results, it has also been proposed that the presence of cholesterol may make an important contribution to the general inability of ACP AO peptides to lyse erythrocyte membranes, which inherently contain high levels of the sterol, in the region of 45 mol% .…”

“…82 Consistent with this suggestion, it was found that increasing levels of membrane cholesterol inhibited the lytic ability of a number of a-ACPs toward membranes of nonmalignant eukaryotic cells and lipid mimics of these membranes, including cecropins, 104,105 and magainins which are amphibian a-ACP AO peptides. 106,107 Based on these and other results, it has also been proposed These peptides have been assayed both in vitro and in vivo, using murine models when intracellularly expressed in tumors of xenografted human bladder carcinoma cells 60,79,330 Magainin and analogs These peptides utilize multiple anticancer mechanisms that vary with cancer cell type, and include apoptosis and necrosis via membrane lysis or pore formation These peptides have been assayed both in vitro and in vivo, using murine models when injected intratumorally into xenografted human melanoma cells 60,79 Epinecidin-1 This peptide utilizes multiple anticancer mechanisms that vary with cancer cell type, and include apoptosis and necrosis via membrane lysis or pore formation Currently, this peptide only appears to have been assayed in vitro 88,89,331 Polybia-MP1 For cancers reported, this peptide kills cancer cells through necrosis induced by membrane lysis or pore formation Currently, this peptide only appears to have been assayed in vitro 79,280,281,332 a-ACP T Melittin This peptide utilizes multiple anticancer mechanisms that vary with cancer cell type, and include apoptosis and necrosis via membrane pore formation and membrane lysis, either mediated directly by melittin or indirectly via the activation of cancer cell phospholipases This peptide has been assayed both in vitro and in vivo, using murine models and a variety of melittin constructs. For example, when injected intratumorally both as a melittin-avidin conjugate into murine melanoma cells and as a melittin-adenovirus construct into xenografted human hepatocarcinoma cells 60,79,333 LL-37 This peptide can not only promote cancers, but also shows anticancer effects specific for gastric tissue, which appears to be an antimitogenic effect mediated through proteosome inhibition and the induction of tumor suppressor proteins This peptide has been assayed both in vitro and in vivo, using murine models when injected intratumorally into xenografted human gastric adenocarcinoma cells 60,79,113,…”

Antimicrobial peptides from amphibians

“…They can inhibit 80% of sperm motility at a concentration 100 mg/ml within 30 min (21). At the same concentration, magainin also show similar sperm immobilization ability (94). In addition, two synthetic magainins, magainin A and magainin G, show spermicidal activity by altering the plasma membranes of sperms (95).…”

Insights of Spermicidal Research: An Update

“…It is also active against various STI-causing pathogens but not against HIV-1 and HIV-2. It is reported that effectiveness of magainin as a contraceptive in vivo is possibly due in part to the removal of cholesterol from sperm membranes [69].…”