Ultrastructural response of the nuclear envelope (NE) of C6-glioma cells to cisplatin-induced apoptosis

Abstract

The early response of the nuclear envelope of C6-glioma cells (t < or = 24 h), treated with a cytostatic dose of cisplatin in culture (5 microg/ml) included formation of slim and deep invaginations formed by either the inner or both membranes. The invaginations made of the complete NE often extended up to the enlarged nucleoli. In some of them, nucleus-like material occurred at their cytoplasmic site suggesting its enhanced nucleus-to-cytoplasm transport. Some nuclear pores in the invagination-forming cells were covered by dome-shaped "caps" protruding into the karyoplasm. The "capped" pores were absent in the cells that were initially more damaged. At 48 to 72 h, we found a small number of large and hyperlobulated cells with some small lobules containing a rarefied chromatin and focally disintegrated NE. The lamina-free remnants of the NE with a swollen perinuclear cistern were still present at 72-96 h when the population entered the execution phase of apoptotic death.