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Structure-apoptotic potency evaluations of novel sterols using human leukemic cells
B H Johnson1, M J Russell, A S Krylov
1Department of Human Biological Chemistry and Genetics, The University of Texas Medical Branch, Galveston 77555-0645, USA.
Lipids
|April 27, 2000
Summary
Three cholesterol analogs induced apoptotic cell death in human leukemia cells. The most potent compounds, 25-hydroxycholesterol and 15-ketocholestenol, suppressed oncogene mRNA and show potential as chemotherapeutic agents.
Area of Science:
- Biochemistry
- Cell Biology
- Oncology
Background:
- Oxysterols, oxidized cholesterol metabolites, are implicated in various biological processes.
- Certain oxysterols exhibit cytotoxic effects on cancer cells.
- Understanding the apoptotic potential of novel oxysterols is crucial for therapeutic development.
Purpose of the Study:
- To characterize the apoptotic cell death-inducing ability of three oxidized cholesterol analogs: 15-ketocholestenol (K15), 15-ketocholestenol hydroxyethyl ether (CK15), and 7-ketocholesterol hydroxyethyl ether (CK7).
- To compare their potency against the known apoptotic agent 25-hydroxycholesterol (25OHC) in CEM-C7-14 human leukemic cells.
- To elucidate the mechanism of cell death and identify potential chemotherapeutic candidates.
Main Methods:
- Cell viability assays (dye exclusion, MTT assay) to determine oxysterol potency.
- TUNEL assay to quantify DNA fragmentation.
- ELISA assay for DNA fragment release.
- Western blot analysis for c-myc mRNA suppression.
- Hoechst and Annexin V staining to confirm apoptosis.
Main Results:
- Oxysterol potency for cell kill was ranked: 25OHC > K15 > CK15 > CK7.
- All tested oxysterols suppressed c-myc mRNA, with 25OHC and K15 being most effective.
- Apoptotic pathway confirmed by nuclear chromatin condensation and plasma membrane inversion.
- TUNEL, MTT, and ELISA assays corroborated the observed potency order.
Conclusions:
- 25-hydroxycholesterol (25OHC), 15-ketocholestenol (K15), and potentially 15-ketocholestenol hydroxyethyl ether (CK15) demonstrate significant potential as chemotherapeutic agents.
- These oxysterols induce apoptosis in human leukemic cells through a well-defined pathway.
- Further in vitro and in vivo studies are warranted to explore their therapeutic applications.