CIL-102 Interacts with Microtubule Polymerization and Causes Mitotic Arrest following Apoptosis in the Human Prostate Cancer PC-3 Cell Line

Abstract

There have been no therapeutic agents that provide a survival advantage in hormone-refractory prostate cancer. Recently, the Food and Drug Administration approved docetaxel combined with prednisone for the treatment of patients with advanced metastatic prostate cancer, and it does show a survival benefit. Hence, anti-microtubule drugs might be of benefit in chemotherapy of hormone-refractory prostate cancer. We used metastatic hormone-refractory prostate cancer PC-3 cells to investigate potential molecular mechanisms for CIL-102, a semisynthetic alkaloid derivative. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenylte-trazolium bromide and sulforhodamine B assays indicated that CIL-102 inhibits cell growth dose-dependently. Immunofluorescence microscopy and in vitro tubulin assembly assays indicated that CIL-102 binds to tubulin and disrupts microtubule organization. Flow cytometry showed that CIL-102 causes cells to accumulate in G 2 /M phase and sub-G 0 /G 1 phase. CIL-102-induced apoptosis was also characterized by immunofluorescence microscopy. Western blotting and kinase assays showed that CIL-102 exposure induced up-regulation of cyclin B1 and p34 cdc2 kinase activity and olomoucine, a p34 cdc2 inhibitor, profoundly reduced the number of cells accumulated in mitotic phase. Moreover, Bcl-2 phosphorylation, Cdc25C phosphorylation, and survivin expression were increased. CIL-102-induced apoptosis was associated with activation of caspase-3, but a noncaspase pathway may also be involved, since benzyloxycarbonyl-VAD-fluoromethyl ketone, a pancaspase inhibitor, only partially inhibited the apoptosis, and apoptosisinducing factor was translocated from mitochondria to cytosol. We conclude that CIL-102 induces mitotic arrest and apoptosis by binding to tubulin and inhibiting tubulin polymerization. CIL-102 causes mitotic arrest, at least partly, by modulating cyclin-dependent kinases and then apoptosis executed by caspase and noncaspase pathways.

CHM-1, a novel synthetic quinolone with potent and selective antimitotic antitumor activity against human hepatocellular carcinoma in vitro and in vivo

“…Representative of four independent experiments. the antimitotic agents (25,26). In addition, the CHM-1-induced activation of Cdc2 kinase activity, the elevation of MPM2 phosphoepitopes, and the inhibition of cell growth were all attenuated by roscovitine.…”

Dihydroartemisinine Enhances Dictamnine-induced Apoptosis via a Caspase Dependent Pathway in Human Lung Adenocarcinoma A549 Cells

“…Dictamnine (Dic), a natural alkaloid, was isolated from the root of Dictamnus dasycarpus Turcz, and has been reported to possess anti-platelet aggregation, fungal activity and vascular-relaxing effects (Huang et al, 2005;Huang et al, 2007;Guo et al, 2008). Recently, it was reported that Dic could induce cytotoxicity in human cervix, colon, and oral carcinoma cells (Huang et al, 2005).…”

“…Recently, it was reported that Dic could induce cytotoxicity in human cervix, colon, and oral carcinoma cells (Huang et al, 2005). In addition, derivatives from Dic have been exhibited anticancer activity (Huang et al, 2007).…”

YC-1 suppresses constitutive nuclear factor-κB activation and induces apoptosis in human prostate cancer cells

“…The analytic method was modified from the previous description (12). In brief, cells were incubated with anti-p65 antibody at 37jC for 45 minutes and stained with FITC-conjugated antirabbit IgG antibody plus 1 Ag/mL 4V,6-diamidino-2-phenylindole in PBS for 30 minutes at room temperature.…”

“…Total cell lysate was lysed with lysis buffer as previously described (12). The nuclear protein fractions were separated as described previously (14).…”