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Chemotherapy. 2004 Jun;50(2):55-62.

Mitochondria-targeting drug oligomycin blocked P-glycoprotein activity and triggered apoptosis in doxorubicin-resistant HepG2 cells.

Author information

1
Department of Biochemistry, The Chinese University of Hong Kong, Shatin, China.

Abstract

BACKGROUND:

Mitochondria are key regulators in apoptosis. This suggests that a mitochondrion can be a target for cancer treatment. To examine the feasibility of this approach, we investigated the effect of oligomycin on the induction of apoptosis in drug-resistant cells. As a mitochondrion-targeting agent, oligomycin inhibits mitochondrial F0F1-ATPase. Of 37,000 molecules tested against the 60 human cancer cell lines of the National Cancer Institute, oligomycin is among the top 0.1% most cell line selective agents.

METHODS:

Changes in the doxorubicin (Dox) accumulation and mitochondrial potential (Deltapsim) in human hepatocarcinoma HepG2 and its derivative R-HepG2 with Dox resistance were determined by flow cytometry. P-glycoprotein (Pgp) expression and release of cytochrome c from mitochondria were analyzed by Western blot. Cytotoxicity was examined by DNA fragmentation and the alamar blue assay.

RESULTS:

R-HepG2 cells produced Pgp, showed drug resistance and accumulated less Dox when compared to their parent. In both cell lines, oligomycin depolarized Deltapsim, released cytochrome c and elicited DNA fragmentation. Moreover, oligomycin blocked Pgp activity and accumulated more Dox in R-HepG2. Combined treatment with Dox and oligomycin elicited more cell death.

CONCLUSION:

Our results suggest that oligomycin could bypass Dox resistance and trigger apoptosis in R-HepG2 cells.

PMID:
15211078
DOI:
10.1159/000077803
[Indexed for MEDLINE]

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