title: Differential sensitivity to apoptosome apparatus activation in non-small cell lung carcinoma and the lung.
abstract: The intrinsic apoptosis pathway represents an important mechanism of stress-induced death of cancer cells. To gain insight into the functional status of the apoptosome apparatus in non-small cell lung carcinoma (NSCLC), we studied its sensitivity to activation, the assembly of apoptosome complexes and stability of their precursors, and the importance of X-linked inhibitor of apoptosis (XIAP) in the regulation of apoptosome activity, using cell-free cytosols from NSCLC cell lines and NSCLC tumours and lungs from 62 surgically treated patients. Treatment of cytosol samples with cytochrome c (cyt-c) and dATP induced proteolytic processing of procaspase-9 to caspase-9, which was followed by procaspase-3 processing to caspase-3, and by generation of caspase-3-like activity in 5 of 7 studied NSCLC cell lines. Further analysis demonstrated formation of high-Mr Apaf-1 complexes associated with cleaved caspase-9 in the (cyt-c + dATP)-responsive COLO-699 and CALU-1 cells. By contrast, in A549 cells, Apaf-1 and procaspase-9 co-eluted in the high-Mr fractions, indicating formation of an apoptosome complex unable of procaspase-9 processing. Thermal pre-treatment of cell-free cytosols in the absence of exogenous cyt-c and dATP lead to formation of Apaf-1 aggregates, unable to recruit and activate procaspase-9 in the presence of cyt-c and dATP, and to generate caspase‑3‑like activity. Further studies showed that the treatment with cyt-c and dATP induced a substantially higher increase of caspase-3-like activity in cytosol samples from NSCLC tumours compared to matched lungs. Tumour histology, grade and stage had no significant impact on the endogenous and the (cyt-c + dATP)-induced caspase-3-like activity. Upon addition into the cytosol, the XIAP-neutralizing peptides AVPIAQK and ATPFQEG only moderately heightened the (cyt-c + dATP)-induced caspase‑3‑like activity in some NSCLC tumours. Taken together, the present study provides evidence that the apoptosome apparatus is functional in the majority of NSCLCs and that its sensitivity to the (cyt-c + dATP)-mediated activation is often enhanced in NSCLCs compared to lungs. They also indicate that XIAP does not frequently and effectively suppress the activity of apoptosome apparatus in NSCLCs.
authors.affiliation: Laboratories of Molecular and Cell Biology, Department of Pneumology and Thoracic Surgery, Hospital Bulovka and Third Faculty of Medicine, Charles University in Prague, Prague, Czech Republic.
authors.forename: Erika
authors.initials: E
authors.lastname: Moravcikova
authors.affiliation: Laboratories of Molecular and Cell Biology, Department of Pneumology and Thoracic Surgery, Hospital Bulovka and Third Faculty of Medicine, Charles University in Prague, Prague, Czech Republic.
authors.forename: Evzen
authors.initials: E
authors.lastname: Krepela
authors.affiliation: Laboratories of Molecular and Cell Biology, Department of Pneumology and Thoracic Surgery, Hospital Bulovka and Third Faculty of Medicine, Charles University in Prague, Prague, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Prochazka
authors.affiliation: Department of Pathology, Hospital Bulovka, Prague, Czech Republic.
authors.forename: Kamila
authors.initials: K
authors.lastname: Benkova
authors.affiliation: Division of Pneumology, Department of Pneumology and Thoracic Surgery, Hospital Bulovka and Third Faculty of Medicine, Charles University in Prague, Prague, Czech Republic.
authors.forename: Norbert
authors.initials: N
authors.lastname: Pauk
mesh_terms: D000368:Aged; D017209:Apoptosis / Q000187:drug effects; D053477:Apoptotic Protease-Activating Factor 1 / Q000378:metabolism*; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism* / Q000473:pathology; D053148:Caspase 3 / Q000378:metabolism*; D053453:Caspase 9 / Q000378:metabolism*; D061945:Caspase Inhibitors / Q000494:pharmacology; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000494:pharmacology; D003600:Cytosol / Q000378:metabolism; D003838:Deoxyadenine Nucleotides / Q000494:pharmacology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008168:Lung / Q000166:cytology / Q000378:metabolism*; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000494:pharmacology
chemical_list: D053477:Apoptotic Protease-Activating Factor 1; D061945:Caspase Inhibitors; D003838:Deoxyadenine Nucleotides; D051636:X-Linked Inhibitor of Apoptosis Protein; D045304:Cytochromes c; D053148:Caspase 3; D053453:Caspase 9; C026600:2'-deoxyadenosine triphosphate