R-253 Disrupts Microtubule Networks in Multiple Tumor Cell Lines
Open Access
- 15 June 2006
- journal article
- Published by American Association for Cancer Research (AACR) in Clinical Cancer Research
- Vol. 12 (12), 3831-3842
- https://doi.org/10.1158/1078-0432.ccr-06-0168
Abstract
Purpose: The design and development of synthetic small molecules to disrupt microtubule dynamics is an attractive therapeutic strategy for anticancer drug discovery research. Loss of clinical efficacy of many useful drugs due to drug resistance in tumor cells seems to be a major hurdle in this endeavor. Thus, a search for new chemical entities that bind tubulin, but neither are a substrate of efflux pump, P-glycoprotein 170/MDR1, nor cause undesired side effects, would potentially increase the therapeutic index in certain cancer treatments. Experimental Design: A high-content cell-based screen of a compound library led to the identification of a new class of compounds belonging to a thienopyrimidine series, which exhibited significant antitumor activities. On structure-activity relationship analysis, R-253 [N-cyclopropyl-2-(6-(3,5-dimethylphenyl)thieno[3,2-d]pyrimidin-4-yl)hydrazine carbothioamide] emerged as a potent antiproliferative agent (average EC50, 20 nmol/L) when examined in a spectrum of tumor cell lines. Results: R-253 is structurally unique and destabilizes microtubules both in vivo and in vitro. Standard fluorescence-activated cell sorting and Western analyses revealed that the effect of R-253 on cell growth was associated with cell cycle arrest in mitosis, increased select G2-M checkpoint proteins, and apoptosis. On-target activity of R-253 on microtubules was further substantiated by immunofluorescence studies and selected counter assays. R-253 competed with fluorescent-labeled colchicine for binding to tubulin, indicating that its binding site on tubulin could be similar to that of colchicine. R-253 neither is a substrate of P-glycoprotein 170/MDR1 nor is cytotoxic to nondividing human hepatocytes. Conclusion: Both biochemical and cellular mechanistic studies indicate that R-253 could become a promising new tubulin-binding drug candidate for treating various malignancies.Keywords
This publication has 36 references indexed in Scilit:
- The Potential Role of Proteasome Inhibitors in the Treatment of Lung CancerClinical Cancer Research, 2004
- Cell death by mitotic catastrophe: a molecular definitionOncogene, 2004
- Securin and B-cyclin/CDK are the only essential targets of the APCNature, 2003
- Phosphorylation Site Interdependence of Human p53 Post-translational Modifications in Response to StressOnline Journal of Public Health Informatics, 2003
- Microtubule Structure at Improved ResolutionBiochemistry, 2001
- Phosphorylation and Proteasome-Dependent Degradation of Bcl-2 in Mitotic-Arrested Cells after Microtubule DamageBiochemical and Biophysical Research Communications, 1999
- Differential Taxol-dependent arrest of transformed and nontransformed cells in the G1 phase of the cell cycle, and specific-related mortality of transformed cells.The Journal of cell biology, 1996
- Influence of microtubule-associated proteins on the differential effects of paclitaxel and docetaxelJournal of Protein Chemistry, 1996
- Interactions of colchicine with tubulinPharmacology & Therapeutics, 1991
- Mechanism of action of vinblastine. Binding of [acetyl-3H]-vinblastine to embryonic chick brain tubulin and tubulin from sea urchin sperm tail outer doublet microtubulesBiochemistry, 1975