Procainamide

Procainamide (Procaine amide) is a specific and potent inhibitor of DNA methyltransferase 1 (DNMT1), which reactivates the expression of tumor suppressor factors by demethylating tumor suppressor genes. Procainamide induces vacuolization in various cell types and reduces cell proliferation and migration. Procainamide relaxes airway smooth muscle by activating potassium channels. Procainamide can be used in cancer and arrhythmia research^{[1][2][3][4][5][6]}. IC50 & Target:DNMT1^[1] In Vitro:Procainamide has a K_i of 7.2 μM for DNMT1 inhibition on hemimethylated oligonucleotide substrates and a K_i of 4600 μM for DNMT1 inhibition on unmethylated oligonucleotide substrates^[1].
Procainamide (0.5 mM; 96 h) causes loss of CpG methylation in HCT116 cells and affects centromeric repeat sequences and single-copy genes^[1].
Procainamide (0-10 mM) concentration-dependently relaxes bovine tracheal contractions induced by methacholine (0.3 μM) but does not significantly relax contractions induced by potassium ions (40 mM)^[4].
Procainamide (250 μM-2.5 mM; 0-48 h) does not induce cellular vacuolization at a dose of 250 μM, but induces cellular vacuolization in many cells at a dose of 2.5 mM^[5].
Procainamide (10 μM; 5 d) demethylates ER, p16, and RAR genes in MDA-231, T24, and MCF-7 cell lines^[6].
In Vivo:Procainamide (20 mg/kg; i.p.; once daily for 7 days) demethylates and re-expresses the ER gene in BALB/c mice xenografted with MDA-231 cells^[6].