Vascular disrupting activity and the mechanism of action of EHT 6706, a novel anticancer tubulin polymerization inhibitor.

Tumor blood vessels are an important emerging target for anticancer therapy. Here, we characterize the in vitro antiproliferative and antiangiogenic properties of the synthetic small molecule, 7-ethoxy-4-(3,4,5-trimethoxybenzyl)isoquinolin-8-amine dihydrochloride, EHT 6706, a novel microtubule-disrupting agent that targets the colchicine-binding site to inhibit tubulin polymerization. At low nM concentrations, EHT 6706 exhibits highly potent antiproliferative activity on more than 60 human tumor cell lines, even those described as being drug resistant.

Pharmacological screening and enzymatic assays for apoptosis.

Mitochondria play a central role in the intrinsic pathway of apoptosis. In response to many pro-apoptotic stimuli, mitochondria undergo an irreversible process called mitochondrial membrane permeabilization (MMP). The detection of MMP in isolated mitochondria is most often based on assays that monitor either the loss of the inner transmembrane potential (DYm; classically with Rhodamine 123), permeability transition (PT, cyclosporin A-sensitive matrix swelling), or the release of critical pro-apoptotic intermembrane space effectors.

Analysis of HIV Protease Killing Through Caspase 8 Reveals a Novel Interaction Between Caspase 8 and Mitochondria.

Human Immunodeficiency Virus (HIV) protease initiates apoptosis of HIV-infected cells by proteolytic cleavage of procaspase 8, creating a novel peptide termed casp8p41. Expression of casp8p41 alone is sufficient to initiate caspase-dependent cell death associated with mitochondrial depolarization. Since casp8p41 does not contain the catalytic cysteine at position 360, the mechanism by which casp8p41 initiates apoptosis is unclear.

Mitoparan and target-selective chimeric analogues: membrane translocation and intracellular redistribution induces mitochondrial apoptosis.

Mastoparan, and structurally-related amphipathic peptides, may induce cell death by augmentation of necrotic and/or apoptotic pathways. To more precisely delineate cytotoxic mechanisms, we determined that [Lys(5,8)Aib(10)]mastoparan (mitoparan) specifically induces apoptosis of U373MG and ECV304 cells, as demonstrated by endonuclease and caspase-3 activation and phosphatidylserine translocation. Live cell imaging confirmed that, following translocation of the plasma membrane, mitoparan specifically co-localizes with mitochondria.