MULTIPLE CENTROSOMAL MICROTUBULE-ORGANIZING CENTERS AND INCREASED MICROTUBULE STABILITY ARE EARLY FEATURES OF VP-16-INDUCED APOPTOSIS IN CCRF-CEM CELLS

Microtubular reorganisation contributing to apoptotic morphology occur s in normal and neoplastic cells undergoing apoptosis induced by cytot oxic drugs [1-3]. The aim of this study was to correlate the changes i n the microtubules (MTs) with behaviour of the centrosome in apoptotic cells, and to see whether post-translational changes in tubulin occur red with the emergence of apoptotic MT bands. Apoptosis was induced in the human T-cell leukaemia line (CCRF-CEM) by treatment with 17 mu M etoposide over a 4 h period. The time course of changes was assessed u sing flow cytometry (FCM) and immunocytochemistry in cells labelled fo r a centrosomal antigen (CSP-alpha) or alpha-tubulins. One hour follow ing treatment we observed multiple centrosomal microtubule organising centres (MTOCs) associated with the nucleus and the transient appearan ce of a subset of stable MTs detected with an antibody specific for ac etylated alpha-tubulin, as the bands of MTs which lobulate the nucleus are formed. The altered properties of the MTs thus reflect changes in function as apoptosis progresses. (C) 1997 Elsevier Science Ltd.