Vol. 60, Issue 6, 1235-1242, December 2001

A New Bis-Indole, KARs, Induces Selective M Arrest with Specific Spindle Aberration in Neuroblastoma Cell Line SH-SY5Y

Begoña Comín-Anduix, Neus Agell, Oriol Bachs, Judit Ovádi, and Marta Cascante

Departments of Biochemistry and Molecular Biology (B.C.-A., M.C.) and Cell Biology (N.A., O.B.), Institut d'Investigacions Biomèdiques August Pi i Sunyer, Faculty of Chemistry, University of Barcelona, Barcelona, Spain; and Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Budapest, Hungary

KARs, new semisynthetic antitumor bis-indole derivatives, were found to be inhibitors of tubulin polymerization with lower toxicity than vinblastine or vincristine, used in chemotherapy. Here, we compare the effect of KARs with those of vinblastine and vincristine on cell viability, cell proliferation, and cell cycle in neuroblastoma cell line (SH-SY5Y). At concentrations of the different compounds equivalent in causing 50% of inhibition of cell growth, KARs induced a complete arrest in the G₂/M phase, whereas vinblastine and vincristine induced a partial arrest in both G₀/G₁ and G₂/M. Moreover, a combination of KAR-2 and W13 (an anticalmodulin drug) qualitatively caused a similar arrest in both G₀/G₁ and G₂/M than vinblastine. Levels of cyclin A and B1 were higher in KARs-treated cells than in vinblastine- or vincristine-treated cells. Cdc2 activity was much higher in KAR-2 than in vinblastine-treated cells, indicating a stronger mitotic arrest. The effect of KAR2 and vinblastine on microtubules network was analyzed by immunostaining with anti-tubulin antibody. Results indicated that KAR-2-induces the formation of aberrant mitotic spindles, with not apparent effect on interphase microtubules, whereas vinblastine partially destroyed interphase microtubules coexisting with normal and aberrant mitotic spindles.