RheoSwitch synthetic nuclear receptor (RTS) (RTS)

The RheoSwitch synthetic nuclear receptor is a ligand-inducible gene expression system derived from the insect ecdysone receptor (EcR) and adapted for human gene therapy (Precigen, 2024). It functions as a synthetic transcription factor that remains inactive until the administration of a specific small-molecule inducer, such as veledimex (Barrett et al., 2018). Upon binding the inducer, the receptor undergoes a conformational change that allows it to heterodimerize with a partner protein, typically a modified retinoid X receptor (RXR), and bind to specific DNA response elements to initiate the transcription of a therapeutic transgene (Chiocca et al., 2019). This system is primarily utilized to provide precise, dose-dependent control over the expression of potent biological agents like Interleukin-12 (IL-12) in oncology settings (Precigen, 2024). By allowing the "switching on" and "off" of gene expression, it aims to maximize therapeutic efficacy while minimizing systemic toxicity (Chiocca et al., 2019). Clinical applications have focused on treating recurrent glioblastoma and other solid tumors where localized, controlled immune activation is required (Barrett et al., 2018). The ability to modulate gene expression via an oral drug provides a unique safety mechanism for high-potency genetic medicines (Precigen, 2024).

Other names

Ecdysone receptor-based gene switchEcR-based inducible systemRheoSwitch Therapeutic SystemVeledimex-inducible switch

The inducer drug (e.g., veledimex) binds to the ligand-binding domain of a modified insect ecdysone receptor, triggering its heterodimerization with a retinoid X receptor (RXR) and subsequent binding to a specific DNA response element to initiate transcription of a linked therapeutic transgene (Chiocca et al., 2019).