BACKGROUND: Tubeimoside I (TBMS1) was isolated from the tubers of Bolbostemma paniculatum (Maxim.) Franquet. TBMS1 shows potent anti-tumor activity. The present study was conducted to investigate the anti-microtubule role of TBMS1 and its binding site of tubulin. METHODS: Cell growth inhibition was measured by MTT after treatment with TBMS1. Uptake kinetics of TBMS1 by human nasopharyngeal carcinoma CNE-2Z cell line (CNE-2Z) was assayed by HPLC. Microtubule protein (MTP) was prepared from porcine brain through two cycles of polymerization-depolymerization in a high molarity buffer. Inhibition of MTP polymerization induced by TBMS1 was determined by a turbidity measurement and a sedimentation assay; the interactions of TBMS1 with tubulin within CNE-2Z cells were investigated by immunofluorescence microscopy and immunoblotting. TBMS1 was tested for its ability to inhibit binding of known tubulin ligands through competitive binding assay. RESULTS: TBMS1 displayed growth inhibitory activity against CNE-2Z cells with IC(50) value of 16.7 microM for 72 h. HPLC analysis of TBMS1 uptake by CNE-2Z cells displayed the initial slow TBMS1 uptake and then gradually reaching an maximum uptake near 18 h. CNE-2Z cells treated with TBMS1 (25 microM, 3 h) were sufficient to cause the microtubular network disruption. Immunoblot analysis showed that the proportion of cytosolic tubulin of cells treated with TBMS1 increased in a time- and concentration-dependent manner. TBMS1 did not inhibit the binding of vinblastine to tubulin. Colchicine binding to tubulin was inhibited in the presence of TBMS1. CONCLUSIONS: TBMS1 is an anti-microtubule agent, and its binding site of tubulin is the colchicine binding site of tubulin.
BACKGROUND:Tubeimoside I (TBMS1) was isolated from the tubers of Bolbostemma paniculatum (Maxim.) Franquet. TBMS1 shows potent anti-tumor activity. The present study was conducted to investigate the anti-microtubule role of TBMS1 and its binding site of tubulin. METHODS: Cell growth inhibition was measured by MTT after treatment with TBMS1. Uptake kinetics of TBMS1 by humannasopharyngeal carcinomaCNE-2Z cell line (CNE-2Z) was assayed by HPLC. Microtubule protein (MTP) was prepared from porcine brain through two cycles of polymerization-depolymerization in a high molarity buffer. Inhibition of MTP polymerization induced by TBMS1 was determined by a turbidity measurement and a sedimentation assay; the interactions of TBMS1 with tubulin within CNE-2Z cells were investigated by immunofluorescence microscopy and immunoblotting. TBMS1 was tested for its ability to inhibit binding of known tubulin ligands through competitive binding assay. RESULTS:TBMS1 displayed growth inhibitory activity against CNE-2Z cells with IC(50) value of 16.7 microM for 72 h. HPLC analysis of TBMS1 uptake by CNE-2Z cells displayed the initial slow TBMS1 uptake and then gradually reaching an maximum uptake near 18 h. CNE-2Z cells treated with TBMS1 (25 microM, 3 h) were sufficient to cause the microtubular network disruption. Immunoblot analysis showed that the proportion of cytosolic tubulin of cells treated with TBMS1 increased in a time- and concentration-dependent manner. TBMS1 did not inhibit the binding of vinblastine to tubulin. Colchicine binding to tubulin was inhibited in the presence of TBMS1. CONCLUSIONS:TBMS1 is an anti-microtubule agent, and its binding site of tubulin is the colchicine binding site of tubulin.
Authors: Tina L Tinley; Rachel M Leal; Deborah A Randall-Hlubek; James W Cessac; Lynne R Wilkens; Pemmaraju N Rao; Susan L Mooberry Journal: Cancer Res Date: 2003-04-01 Impact factor: 12.701
Authors: José M Mínguez; Sun-Young Kim; Kenneth A Giuliano; Raghavan Balachandran; Charitha Madiraju; Billy W Day; Dennis P Curran Journal: Bioorg Med Chem Date: 2003-07-31 Impact factor: 3.641
Authors: Richard A Isbrucker; Jennifer Cummins; Shirley A Pomponi; Ross E Longley; Amy E Wright Journal: Biochem Pharmacol Date: 2003-07-01 Impact factor: 5.858
Authors: R Diaz; P A Nguewa; J A Diaz-Gonzalez; E Hamel; O Gonzalez-Moreno; R Catena; D Serrano; M Redrado; D Sherris; A Calvo Journal: Br J Cancer Date: 2009-02-24 Impact factor: 7.640