The antitumor activity of certain substituted nucleosides

Area of Science:

• Medicinal Chemistry
• Cancer Biology
• Pharmacology

Background:

• Cytidine deaminase is a key enzyme in nucleoside analog metabolism.
• Modifications to arabinosylcytosine (araC) analogs aim to alter their metabolic stability and efficacy.
• Understanding structure-activity relationships is crucial for developing new anticancer agents.

Purpose of the Study:

• To synthesize and evaluate novel arabinosylcytosine (araC) analogs for antitumor activity.
• To investigate the impact of specific chemical modifications on the activity and metabolic stability of araC analogs.
• To assess the in vitro and in vivo efficacy of selected compounds against leukemia models.

Main Methods:

• Synthesis of new arabinosylcytosine (araC) analogs, including 5-amino-araU.
• In vitro testing of compound cytotoxicity against lymphoid leukemic L 5178 Y cells.
• In vivo evaluation of 5-amino-araU against L 1210 mouse leukemia.
• Assessment of compound susceptibility to cytidine deaminase.

Main Results:

• Several O'-alkylated and N4-alkylated araC analogs were synthesized and tested.
• Modifications like O'-alkylation, N4-exo-alkylation, and amino group repositioning reduced cytidine deaminase susceptibility.
• These modifications also substantially decreased the cytotoxic activity of the tested analogs.
• 5-ethyl-2'-deoxyuridine showed moderate in vitro inhibition of L 5178 Y cell growth.

Conclusions:

• Chemical modifications that abolish cytidine deaminase susceptibility in araC analogs also diminish their cytotoxic potential.
• Further research is needed to balance metabolic stability with potent anticancer activity.
• The biological significance of 5-ethyl-2'-deoxyuridine warrants further investigation in leukemia treatment.