Engineered ecdysone receptor (RTS-EcR)

The Engineered RheoSwitch Therapeutic System (RTS) ecdysone receptor is a synthetic gene regulation platform derived from the insect ecdysone receptor (EcR), specifically from species like Choristoneura fumiferana. This system is engineered to function as a molecular switch in mammalian cells, providing precise, dose-dependent control over the expression of therapeutic transgenes (Palli et al., 2003). The receptor typically consists of a chimeric protein that forms a heterodimer with a human retinoid X receptor (RXR) or a modified version thereof. Transcription is only initiated when a specific, non-steroidal small-molecule inducer, such as Veledimex (RG-115830), binds to the receptor complex (Precigen, 2023). This technology is primarily utilized in oncology, such as in the treatment of recurrent glioblastoma, to locally produce potent cytokines like Interleukin-12 while avoiding the systemic toxicity associated with their continuous expression (Chiocca et al., 2019). By allowing clinicians to "turn on" or "turn off" gene expression via oral drug administration, the RTS ecdysone receptor offers a unique safety profile and therapeutic flexibility in the field of gene therapy.

Other names

RheoSwitch Therapeutic SystemRTSModified ecdysone receptorChimeric ecdysone receptorEcR-based gene switchEngineered RheoSwitch Therapeutic System ecdysone receptor

The engineered ecdysone receptor acts as a ligand-inducible transcription factor. In the absence of its specific activator, the receptor complex is transcriptionally inactive. Upon binding a synthetic ligand such as Veledimex, the receptor undergoes a conformational change that enables it to bind to specific DNA response elements and recruit co-activators, thereby initiating the transcription of a downstream therapeutic gene (Karzenowski et al., 2005; Chiocca et al., 2019).