Results from ultrastructural immunocytochemistry on glutaraldehyde-fixed cells confirmed and extended findings previously obtained with immunofluorescence. A microtubule-associated protein (MAP) of 210,000 molecular weight was shown to be specifically associated with all cytoplasmic and mitotic microtubules along their entire length in primate cells. Specific labeling with the anti-MAP antibody...

We have studied the effect of colchicine and related compounds on secretion of enzymes by thioglycollated-elicited mouse peritoneal macrophages in culture. Colchicine stimulated secretion of inducible neutral proteinase activities of elastase (EC 3.4.21.11), collagenase (EC 3.4.24.3), gelatinase (pepsin B; EC 3.4.23.2), and azocaseinase 2- to 6-fold for a period of several days, but inhibited t...

Sixty-one phenyl 4-(2-oxoimidazolidin-1-yl)benzenesulfonates (PIB-SOs) and 13 of their tetrahydro-2-oxopyrimidin-1(2H)-yl analogues (PPB-SOs) were prepared and biologically evaluated. The antiproliferative activities of PIB-SOs on 16 cancer cell lines are in the nanomolar range and unaffected in cancer cells resistant to colchicine, paclitaxel, and vinblastine or overexpressing the P-glycoprote...

The synthesis of diverse three-dimensional libraries has become of paramount importance for obtaining better leads for drug discovery. Such libraries are predicted to fare better than traditional compound collections in phenotypic screens and against difficult targets. Herein we report the diversity-oriented synthesis of a compound library using rhodium carbenoid chemistry to access structurall...

Microtubules (MTs) are key components of the cytoskeleton for all eukaryotes and are vital for cellular processes such as mitotic spindle formation, intracellular transport, vesicle formation, cellular signaling, and migration. These functions depend on the dynamic nature of MTs, which arises from the polymerization and depolymerization events of individual heterodimers, made up of αand β-tubul...

Cryptophycins are a class of 16-membered highly cytotoxic macrocyclic depsipeptides isolated from cyanobacteria. The biological activity is based on their ability to interact with tubulin. They interfere with microtubule dynamics and prevent microtubules from forming correct mitotic spindles, which causes cell-cycle arrest and apoptosis. Their strong antiproliferative activities with 100-fold t...

We have studied the distribution of myosin and tubulin molecules inside the same tissue culture cells by using two antibodies labeled with contrasting fluorochromes. Antimyosin raised against human platelet myosin was labeled with rhodamine. Antitubulin raised against sea urchin vinblastine-induced tubulin crystals was labeled with fluorescein. The two antibodies stained entirely different stru...

The ability of platelets to adsorb vinblastine has been used to treat patients with immune thrombocytopenia. It is hypothesized that the drug-platelet complex is coated with antibody, taken up by macrophages which are then destroyed by the drug. We gave 16 courses of vinblastine-platelets to six patients with immune thrombocytopenia. Only one patient responded, and therefore we examined possibl...

Analysis of sedimentation velocity data for indefinite self-associating systems is often achieved by fitting of weight average sedimentation coefficients (s(20,w)) However, this method discriminates poorly between alternative models of association and is biased by the presence of inactive monomers and irreversible aggregates. Therefore, a more robust method for extracting the binding constants ...

Cancer drug researchers have been seeking microtubule-inhibiting agents (MIAs) with higher bioactivity and lower toxicity than currently marketed drugs. WX-132-18B, a novel structural compound synthesized at our institute, specifically bound to the colchicine-binding site on tubulin rather than the vinblastine site, and concentration-dependently reduced microtubule content via depolymerization....