Ultrastructural morphology and localisation of cisplatin-induced platinum-DNA adducts in a cisplatin-sensitive and -resistant human small cell lung cancer cell line using electron microscopy.

Abstract

Ultrastructural morphology (transmission electron microscopy) and localisation of cisplatin-induced platinum (Pt)-DNA adducts (immunoelectron microscopy) were analysed in the human small cell lung cancer cell line GLC(4) and its 40-fold in vitro acquired cisplatin-resistant subline GLC(4)-CDDP, which is characterised by, among other things, a decreased DNA platination. Immunolabelling of Pt-DNA adducts was performed with the polyclonal antibody GPt, known to detect the main Pt-containing intrastrand and interstrand DNA adducts. Morphological analysis of GLC(4) and GLC(4)-CDDP at the ultrastructural level showed cells with a high nucleus/cytoplasm ratio with the majority of nuclei containing one or more nucleoli. GLC(4)-CDDP showed, in contrast to GLC(4), an extensive Golgi apparatus and an increased number of mitochondria. DNA platination was detectable in both GLC(4) and GLC(4)-CDDP. Immunoelectron microscopy showed Pt-DNA adducts primarily in the nucleus, preferentially at loci with high-density chromatin (e.g. heterochromatin, pars granulosa around nucleoli, condensed DNA in proliferating and apoptotic cells), and in mitochondria. The level of detectable Pt-DNA adducts was cell cycle status-dependent. In both cell lines, Pt-DNA adduct levels increased from non-dividing interphase cells to dividing cells and were highest in cells undergoing apoptosis. Overall localisation of Pt-DNA adducts was comparable in GLC(4) and GLC(4)-CDDP cells.

• Authors: C Meijera, M J van Luyn, E F Nienhuis, N Blom, N H Mulder, E G de Vries
• Journal: Biochemical pharmacology (Biochem Pharmacol) Vol. 61 Issue 5 Pg. 573-8 (Mar 01 2001) ISSN: 0006-2952 [Print] England
• PMID: 11239500 (Publication Type: Journal Article)

Chemical References

• Antibodies
• Antineoplastic Agents
• DNA Adducts
• DNA, Neoplasm
• Cisplatin

Topics

• Antibodies (immunology)
• Antineoplastic Agents (pharmacology)
• Carcinoma, Small Cell (pathology, ultrastructure)
• Cisplatin (pharmacology)
• DNA Adducts (immunology, ultrastructure)
• DNA, Neoplasm (drug effects, metabolism)
• Drug Resistance, Neoplasm (physiology)
• Humans
• Immunohistochemistry
• Microscopy, Electron
• Tumor Cells, Cultured