Controlled cell killing by a recombinant nonsegmented negative-strand RNA virus

Area of Science:

• Virology
• Molecular Biology
• Oncology

Background:

• Paramyxoviruses, like simian virus 5 (SV5), typically cause minimal cell death in infected cell lines.
• The potential of using viruses as vectors for targeted cancer therapy is an area of active research.
• Herpes simplex virus thymidine kinase (TK) is a well-established enzyme for prodrug-mediated cell killing.

Purpose of the Study:

• To engineer a recombinant SV5 (rSV5-TK) expressing the herpes simplex virus thymidine kinase (TK) gene.
• To evaluate the efficacy of rSV5-TK in mediating prodrug-induced cancer cell death.
• To assess the potential of SV5 as a viral vector for cancer therapeutics.

Main Methods:

• Construction of recombinant SV5 (rSV5-TK) encoding HSV TK.
• Infection of MDBK cells with rSV5-TK and treatment with prodrugs (acyclovir/ganciclovir).
• Time-lapse microscopy to observe cell death mechanisms and assessment of cell viability.
• Testing in various human and mouse cell lines, including persistently infected cells.

Main Results:

• rSV5-TK infected cells showed time-dependent cell death in the presence of acyclovir or ganciclovir.
• No significant toxicity was observed in the absence of prodrugs or with a control virus expressing GFP.
• Apoptotic cell death was observed in rSV5-TK infected cells treated with acyclovir.
• Persistent infection with rSV5-TK maintained TK expression and prodrug sensitivity.
• The rSV5-TK and ganciclovir combination effectively killed all tested mouse and human cell lines.

Conclusions:

• Recombinant SV5 expressing HSV TK can induce targeted cancer cell death via prodrugs.
• This study demonstrates the potential of negative-strand RNA viruses as therapeutic vectors for cancer.
• SV5-based vectors offer a promising platform for developing novel oncolytic virotherapies.