Related Experiment Video
Updated: Aug 5, 2025
Formation of Covalent DNA Adducts by Enzymatically Activated Carcinogens and Drugs In Vitro and Their Determination by 32P-postlabeling
Published on: March 20, 2018
The Molecular Mechanisms of Oleanane Aldehyde-β-enone Cytotoxicity against Doxorubicin-Resistant Cancer Cells
Natalia Moiseeva1, Daria Eroshenko2, Lidia Laletina1
1The N.N. Blokhin National Medical Research Center of Oncology, Health Ministry of Russia, 115478 Moscow, Russia.
Abstract:
Oleanane aldehyde-β-enone (OA), being the semi-synthetic derivative of the triterpenoid betulin, effectively inhibits the proliferation of HBL-100 and K562 cancer cells (IC50 0.47-0.53 µM), as well as the proliferation of their resistant subclones with high P-gp expression HBL-100/Dox, K562/i-S9 and K562/i-S9_Dox (IC50 0.45-1.24 µM). A molecular docking study, rhodamine efflux test, synergistic test with Dox, and ABC transporter gene expression were used to investigate the ability of OA to act as a P-gp substrate or inhibitor against Dox-resistant cells. We noted a trend toward a decrease in ABCB1, ABCC1 and ABCG2 expression in HBL-100 cells treated with OA. The in silico and in vitro methods suggested that OA is neither a direct inhibitor nor a competitive substrate of P-gp in overexpressing P-gp cancer cells. Thus, OA is able to overcome cellular resistance and can accumulate in Dox-resistant cells to realize toxic effects. The set of experiments suggested that OA toxic action can be attributed to activating intrinsic/extrinsic or only intrinsic apoptosis pathways in Dox-sensitive and Dox-resistant cancer cells, respectively. The cytotoxicity of OA in resistant cells is likely mediated by a mitochondrial cell death pathway, as demonstrated by positive staining with Annexin V-FITC, an increasing number of cells in the subG0/G1 phase, reactive oxygen species generation, mitochondrial dysfunction, cytochrome c migration and caspases-9,-6 activation.
Insights
Oleanane aldehyde-β-enone (OA) effectively inhibits cancer cell proliferation and overcomes drug resistance. OA induces apoptosis through mitochondrial pathways in both sensitive and resistant cancer cells.
Area of Science:
- Pharmacology and Toxicology
- Cancer Biology
- Molecular Biology
Background:
- Drug resistance is a major challenge in cancer therapy.
- P-glycoprotein (P-gp) overexpression contributes to multidrug resistance.
- Novel compounds are needed to overcome P-gp-mediated resistance.
Purpose of the Study:
- To investigate the efficacy of oleanane aldehyde-β-enone (OA) against cancer cells, including drug-resistant ones.
- To determine OA's mechanism of action, particularly its interaction with P-gp.
- To explore OA's potential to overcome P-gp-mediated drug resistance.
Main Methods:
- Cell proliferation assays (IC50 determination) on sensitive and Dox-resistant cell lines.
- Molecular docking, rhodamine efflux, and synergistic drug testing.
- Analysis of ABC transporter gene expression.
- Apoptosis assays, including Annexin V staining, cell cycle analysis, ROS generation, and caspase activation.
Main Results:
- OA demonstrated potent antiproliferative activity against HBL-100 and K562 cancer cells and their Dox-resistant subclones.
- OA is neither a direct P-gp inhibitor nor a competitive substrate.
- OA effectively overcomes Dox resistance and induces apoptosis via intrinsic/extrinsic pathways, involving mitochondrial dysfunction and caspase activation.
Conclusions:
- OA is a promising agent for overcoming P-gp-mediated multidrug resistance in cancer.
- OA's cytotoxicity is mediated by the induction of apoptosis through mitochondrial pathways.
- OA warrants further investigation as a potential therapeutic agent for resistant cancers.
Related Concept Videos
02:56Treatment Resistant Cancers
01:46Electron Transport Chain: Complex I and II
ROS generation is regulated and maintained at moderate levels necessary...
02:57Targeted Cancer Therapies
There are several types of targeted therapies against...