Discovery of Deuterated 3,4-Dihydro-benzo[e][1,4]diazepine-2,5-dione Derivatives as Potent, Selective and Orally Bioavailable ROCK2 Inhibitors.

Rho-associated coiled-coil-containing kinase 2 (ROCK2) is a key regulator of cellular motility and invasion and represents a promising therapeutic target for metastatic breast cancer. Through systematic structure-activity relationship (SAR) studies, we designed and synthesized a novel series of 1-methyl-3,4-dihydro-1H-benzo[e][1,4]diazepine-2,5-dione derivatives as selective ROCK2 inhibitors. Strategic deuterium incorporation during structural optimization was employed to enhance pharmacokinetic profiles. This effort led to the identification of compound 22d, a highly potent deuterated analog with excellent ROCK2 inhibitory activity (IC50 = 13 nM) and remarkable selectivity (≥769-fold over ROCK1). In functional assays, 22d exhibited robust antimetastatic activity in vitro and significantly suppressed tumor metastasis in MDA-MB-231 breast cancer xenograft models. Mechanistically, its antimetastatic effects were attributed to selective inhibition of STAT3 phosphorylation at tyrosine 705 (Y705). Collectively, these findings establish 22d as a novel lead compound that impairs breast cancer metastasis through targeted disruption of the ROCK2-STAT3 signaling axis, providing a promising foundation for further therapeutic development against metastatic breast cancer.