MicroRNA-sensitive oncolytic measles viruses for cancer-specific vector tropism

Area of Science:

• Oncolytic virotherapy
• Molecular virology
• Cancer biology

Background:

• Oncolytic measles viruses (MV) are engineered for tumor-specific therapy, with ongoing trials for glioblastoma (GBM).
• Controlling viral tropism using microRNA (miRNA)-target sequences is a strategy to enhance safety and specificity.
• miRNA-7 is downregulated in gliomas but abundant in normal brain tissue, presenting a therapeutic target window.

Purpose of the Study:

• To engineer a microRNA-7-sensitive oncolytic measles virus.
• To evaluate the virus's safety and efficacy in glioblastoma models.
• To demonstrate tissue-specific tropism restriction by endogenous miRNA-7.

Main Methods:

• Engineered MV with miRNA-7 target sites in the 3'-untranslated region of the fusion gene.
• Assessed viral replication, spread, and oncolytic efficacy in GBM xenografts and immunocompetent mouse models.
• Analyzed viral replication in primary human brain tumor and normal tissue samples.

Main Results:

• The engineered MV showed miRNA-7-mediated inhibition of viral spread and progeny production.
• The virus retained significant oncolytic efficacy against glioblastoma xenografts.
• miRNA-7-mediated inhibition protected mice from lethal MV challenge and restricted viral replication in human brain tissues.

Conclusions:

• Tissue-specific microRNA targeting can regulate oncolytic measles virus replication and gene expression.
• This strategy enhances tumor specificity without compromising oncolytic efficacy.
• Engineered miRNA-sensitive MV represents a promising approach for safer glioblastoma treatment.