TUSC2 (tumor suppressor gene replacement)

Class

Non-viral, lipid-nanoparticle-delivered TUSC2 tumor suppressor gene therapy (plasmid DNA in a lipoplex/ONCOPREX delivery system)

Pathway

Restoration of TUSC2 tumor-suppressor expression, downstream RAS/MAPK and apoptotic signaling

TUSC2 (also known as FUS1) is a tumor suppressor gene located in a chromosomal region frequently deleted or silenced in lung and other cancers. Loss of TUSC2 expression removes a natural brake on proliferative and survival signaling, particularly through the RAS/MAPK cascade and related apoptotic pathways, allowing malignant cells to grow and resist cell death. Because TUSC2 is typically absent rather than mutated into an active oncoprotein, the therapeutic rationale is gene replacement: reintroducing a functional copy of the gene into tumor cells to restore its regulatory activity. This is accomplished by packaging TUSC2-encoding plasmid DNA into lipid nanoparticles (a lipoplex delivery system) that can fuse with cell membranes and deliver genetic material without relying on a viral vector, avoiding some of the immunogenicity and manufacturing complexity associated with viral gene therapy. Once expressed, TUSC2 protein is thought to dampen oncogenic signaling and promote apoptosis in tumor cells. This mechanism is broadly relevant to cancers characterized by loss of chromosome 3p21.3 tumor suppressor function, most notably non-small cell lung cancer, and represents a gene-replacement strategy distinct from conventional small-molecule pathway inhibition.