Document Detail

Chemotherapy drug response in ovarian cancer cells strictly depends on a cathepsin D-Bax activation loop.
MedLine Citation:
PMID:  18657225     Owner:  NLM     Status:  MEDLINE    
The ovarian cancer cell lines A2780 (wild-type p53) and NIHOVCAR3 (mutated p53) showed, respectively, sensitivity and resistance towards several chemotherapy drugs. We hypothesized that the two cell lines differ in their ability to activate the intrinsic death pathway and have, therefore, dissected the lysosome-mitochondrion signalling pathway by pharmacological inhibition or genetic manipulation of key regulators and executioners. Biochemical and morphological confocal fluorescence studies showed that: (1) In A2780 cells bcl-2 is expressed at an undetectable level, whereas Bax is expressed at a rather high level; by contrast, bcl-2 is highly expressed and Bax is expressed at extremely low levels in NIHOVCAR3 cells; (2) Chemotherapy treatment reduced the expression of bcl-2 in NIHOVCAR3 cells, yet these cells resisted to drug toxicity; (3) Cathepsin D (CD), not cathepsin B or L, mediates the activation of the mitochondrial intrinsic death pathway in A2780 cells; (4) Lysosome leakage and cytosolic relocation of CD occurs in the chemosensitive A2780 cells, not in the chemoresistant NIHOVCAR3 cells; (5) Bax is essential for the permeabilization of both lysosomes and mitochondria in A2780 cells exposed to chemotherapy drugs; (6) CD activity is mandatory for the oligomerization of Bax on both mitochondrial and lysosomal membranes; (7) Bax activation did not occur in the resistant NIHOVCAR3 cells despite their high content in CD. The present data are consistent with a model in which on treatment with a cytotoxic drug the activation of a CD-Bax loop leads to the generalized permeabilization of lysosomes and eventually of mitochondria, thus reaching the point of no return, and culminates with the activation of the caspase cascade. Our data also imply that dysfunctional permeabilization of lysosomes contributes to the development of chemoresistance.
Roberta Castino; Claudia Peracchio; Alessandra Salini; Giuseppina Nicotra; Nicol F Trincheri; Marina Démoz; Guido Valente; Ciro Isidoro
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-07-24
Journal Detail:
Title:  Journal of cellular and molecular medicine     Volume:  13     ISSN:  1582-4934     ISO Abbreviation:  J. Cell. Mol. Med.     Publication Date:  2009 Jun 
Date Detail:
Created Date:  2010-06-23     Completed Date:  2010-10-07     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101083777     Medline TA:  J Cell Mol Med     Country:  England    
Other Details:
Languages:  eng     Pagination:  1096-109     Citation Subset:  IM    
Department of Medical Sciences, "A. Avogadro" University, Novara, Italy.
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MeSH Terms
Antineoplastic Agents / pharmacology*
Apoptosis / drug effects
Cathepsin D / genetics,  metabolism*
Cell Line, Tumor
Cell Survival / drug effects
Cisplatin / pharmacology
Dose-Response Relationship, Drug
Etoposide / pharmacology
Lysosomes / drug effects,  metabolism
Membrane Potential, Mitochondrial / drug effects
Microscopy, Fluorescence
Ovarian Neoplasms / genetics,  metabolism,  pathology
Paclitaxel / pharmacology
Protein Transport / drug effects
RNA Interference
Signal Transduction / drug effects*
bcl-2-Associated X Protein / genetics,  metabolism*
Reg. No./Substance:
0/Antineoplastic Agents; 0/BAX protein, human; 0/bcl-2-Associated X Protein; 15663-27-1/Cisplatin; 33069-62-4/Paclitaxel; 33419-42-0/Etoposide; EC D

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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