H19 promoter (H19)

The H19 promoter is a regulatory DNA sequence that controls the expression of the H19 long non-coding RNA (lncRNA), a gene that is paternally imprinted and primarily expressed during fetal development (Ariel et al., 2007). In adult tissues, the H19 promoter is typically silenced, but it becomes highly reactivated in a wide range of solid tumors, including bladder, pancreatic, and ovarian cancers (Sidi et al., 2008). This tumor-specific reactivation is exploited in gene therapy through constructs like BC-819 (Inodiftagene vixotigamide), which places the Diphtheria Toxin A-subunit (DTA) gene under the control of the H19 promoter (Mizrahi et al., 2009). When these plasmids are delivered to H19-overexpressing cancer cells, the promoter drives the production of DTA, a potent enzyme that inhibits protein synthesis by ADP-ribosylating elongation factor 2 (EF-2) (Smaldone & Davies, 2010). This inhibition leads to rapid apoptotic cell death specifically within the tumor environment. Because the H19 promoter remains inactive in most healthy adult cells, this approach offers a high degree of therapeutic selectivity and reduced systemic toxicity (BioSight Ltd., 2023). Clinical trials have demonstrated the potential of this system, particularly in treating non-muscle invasive bladder cancer where local administration is feasible. The strategy represents a form of suicide gene therapy that leverages the unique epigenetic landscape of malignant cells.

Other names

BC-819Inodiftagene vixotigamideDTA-H19H19-DTA constructH19 gene promoter

Selective expression of Diphtheria Toxin A-subunit (DTA) under the control of the H19 promoter, leading to ADP-ribosylation of elongation factor 2 (EF-2), inhibition of protein synthesis, and induction of apoptosis in H19-overexpressing cells.