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Pharmacological basis for cladribine resistance
Kourosh Lotfi1, Gunnar Juliusson, Freidoun Albertioni
1Department of Medicine and Care, Clinical Pharmacology, Faculty of Health Sciences, Linköping University, Linköping, SE-581 85 Sweden.
Leukemia & Lymphoma
|December 25, 2003
Summary
Leukemic cell resistance to cladribine is a significant challenge. Reduced deoxycytidine kinase (dCK) activity is the primary cause of cladribine resistance, impacting treatment efficacy.
Area of Science:
- Pharmacology
- Oncology
- Biochemistry
Background:
- Leukemic cell resistance to cytostatic agents poses a major clinical challenge.
- Understanding cladribine resistance mechanisms is crucial for effective leukemia treatment.
Purpose of the Study:
- To review and analyze data on cladribine resistance mechanisms.
- To highlight recent advances in characterizing enzymes involved in cladribine resistance.
Main Methods:
- Comprehensive review of in vitro and clinical data on cladribine.
- Analysis of activating and inactivating enzyme roles in resistance.
Main Results:
- Cladribine is a prodrug requiring intracellular phosphorylation by deoxycytidine kinase (dCK) and deoxyguanosine kinase.
- Cytotoxicity depends on cladribine-triphosphates (TP) accumulation, influenced by the dCK/5'-nucleotidase (5'-NT) ratio.
- Multifactorial resistance mechanisms include decreased dCK activity, altered nucleotide pools, and increased drug inactivation by 5'-NT.
Conclusions:
- Reduced dCK activity is the predominant factor in cladribine resistance.
- Understanding these mechanisms is vital for optimizing cladribine use and developing new analogues.
- Defective apoptosis induction can also contribute to cladribine resistance.