Apoptosis in HEP2 cells treated with etoposide and colchicine

M. Cervinka 1, J. Cerman 2, J. Peychl 1 and E. Rudolf 1

1 Department of Medical Biology and Genetics, 2 Department of Medical Biochemistry, Charles University in Prague, Faculty of Medicine in Hradec Králové, Hradec Králové, Czech Republic

Aim. To verify the putative involvement of actin and tubulin in the process of blebbing after the treatment of Hep2 cells with a combination of Etoposide (10 µg/ml) and Colchicin (0.2 µg/ml) for 24 hours. Methods. Time-lapse videomicroscopy, immunofluorescence detection of caspase-3, cytokeratin fragment 18, actin and tubulin. Results. Etoposide, a topoisomerase II inhibitor, induces apoptosis in laryngeal epitheloid cell line Hep2. The characteristic feature of this process is extensive membrane blebbing clearly observable on time-lapse videosequences, caspase-3 activation, specific fragmentation of the nucleus as well as detectable changes in cytoskeleton. Colchicin, a microtubule disrupting alkaloid, induces apoptosis in the same cells; however, its extent is limited and dying cells lack the pattern of any blebbing. Cell treated with combination of both chemicals show reduced blebbing as well as caspase-3 activation, with significant changes in actin as well as tubulin structure. Conclusions. Etoposide and Colchicine induce at given concentration apoptosis in Hep2 cells. Despite the different mechanisms by which both chemicals act, their combined effects do not add up, but, rather eliminate each other.

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Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Paris, France; February 9 - 12, 2002; in the section on Apoptosis - Molecular Mechanisms.

This presentation was a winner in our poster contest and was recognized with the Symposium Presidents' Award for Scientific Excellence.