Conditional replication of a recombinant adenovirus studied using neomycin as a selective marker

Area of Science:

• Oncolytic virotherapy
• Molecular virology
• Gene therapy

Background:

• Adenoviruses are DNA viruses with potential for cancer gene therapy.
• E1B-defective adenoviruses exhibit selective replication in tumor cells with deficient p53.
• Targeted oncolytic virotherapy requires viruses with enhanced tumor cell specificity.

Purpose of the Study:

• To construct and characterize a novel E1B-defective adenovirus (r2/Ad) for selective cancer therapy.
• To evaluate the in vitro replication and cytolytic activity of r2/Ad in p53-proficient and p53-deficient human tumor cells.
• To assess the potential of r2/Ad in cancer gene therapy and studying adenovirus replication.

Main Methods:

• Construction of r2/Ad using homologous recombination and neomycin selection in HEK 293 cells.
• In vitro replication assays and cytopathic effect (CPE) evaluation in various human cell lines (U251, EJ, A549, MRC-5).
• Comparative analysis of r2/Ad sensitivity in different p53-status cell lines.

Main Results:

• r2/Ad was successfully constructed and propagated in HEK 293 cells.
• The recombinant virus selectively replicated in and lysed p53-deficient human tumor cells (U251 glioma, EJ bladder).
• r2/Ad showed limited replication in p53-functional cells (A549 adenocarcinoma, MRC-5 fibroblasts).
• U251 cells exhibited higher sensitivity to r2/Ad replication than EJ cells based on CPE.

Conclusions:

• r2/Ad demonstrates selective in vitro replication in p53-deficient tumor cells, highlighting its potential for cancer gene therapy.
• The study provides a valuable tool for investigating the selective replication of E1B-defective adenoviruses.
• Further research into r2/Ad may lead to novel therapeutic strategies for specific cancer types.