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Etoposide-resistance in the multidrug-resistant LZ-8 cells
V Liengswangwong1, M G Haddock, M A Sognier
1Department of Oncology, Mayo Clinic, Rochester, MN.
Biochemistry and Molecular Biology International
|October 1, 1994
Summary
Multidrug-resistant LZ-8 cells show etoposide resistance, not linked to their resistant phenotype. Cytoplasmic factors, not nuclear ones, appear to mediate this resistance in LZ-8 cells.
Area of Science:
- Cell Biology
- Molecular Pharmacology
- Drug Resistance Mechanisms
Background:
- Etoposide is a chemotherapeutic agent that functions by inhibiting topoisomerase II.
- Multidrug resistance (MDR) is a complex phenomenon that can reduce the efficacy of chemotherapy.
- Understanding resistance mechanisms is crucial for improving cancer treatment outcomes.
Purpose of the Study:
- To investigate the mechanism of etoposide resistance in multidrug-resistant LZ-8 cells.
- To determine if the MDR phenotype contributes to etoposide resistance.
- To identify cellular components involved in etoposide resistance.
Main Methods:
- Comparison of etoposide sensitivity between LZ-8 and wild-type V79 cells.
- Analysis of etoposide-induced DNA-topoisomerase II complex formation in whole cells and isolated nuclei.
- Assessment of the contribution of the MDR phenotype to etoposide resistance.
Main Results:
- LZ-8 cells exhibited significant resistance to etoposide compared to V79 cells.
- The MDR phenotype of LZ-8 cells did not significantly account for their etoposide resistance.
- Etoposide-induced DNA-topoisomerase II complexes were reduced in whole LZ-8 cells but not in isolated LZ-8 nuclei.
- This suggests the involvement of cytoplasmic factors in LZ-8 cell etoposide resistance.
Conclusions:
- Cytoplasmic factors play a role in the etoposide resistance observed in LZ-8 cells.
- The mechanism of resistance is not solely dependent on the MDR phenotype or nuclear events.
- Further research into these cytoplasmic factors could reveal novel therapeutic targets.