Molecular Basis of NDT-Mediated Activation of Nucleoside-Based Prodrugs and Application in Suicide Gene Therapy

Area of Science:

• Biochemistry
• Molecular Biology
• Cancer Research

Background:

• Suicide gene therapy offers a targeted approach to cancer treatment.
• Nucleoside-based prodrugs require activation by specific enzymes to exert cytotoxic effects.
• Developing novel enzyme-prodrug systems is crucial for enhancing therapeutic efficacy.

Purpose of the Study:

• To investigate the potential of type II 2 -deoxyribosyltransferase from Lactobacillus delbrueckii (LdNDT) in cancer suicide gene therapy.
• To characterize the enzymatic activity of LdNDT on various nucleoside prodrugs.
• To evaluate the efficacy of the LdNDT/dFAdo system in human cervical cancer cells.

Main Methods:

• Enzymatic assays were performed to confirm the hydrolytic activity of LdNDT on dFUrd, dFAdo, and d6MetPRib.
• Molecular dynamics simulations were utilized to understand the nucleobase dependence of LdNDT activity.
• Cell viability assays were conducted using HeLa cells treated with the LdNDT/dFAdo system.

Main Results:

• LdNDT demonstrated hydrolytic activity against dFUrd, dFAdo, and d6MetPRib, with activity significantly enhanced by acceptor nucleobases (up to 30-fold).
• Molecular dynamics simulations provided insights into the enzyme's strong nucleobase dependence.
• The LdNDT/dFAdo system exhibited significant cytotoxicity against HeLa cells, with low micromolar inhibitory concentrations.

Conclusions:

• The study provides the first evidence for the application of LdNDT in cancer suicide gene therapy.
• The nucleobase-dependent activity of LdNDT highlights its potential for targeted prodrug activation.
• The promising results warrant further investigation for the clinical implementation of nucleoside 2 -deoxyribosyltransferases in cancer treatment.