GLUD1 inhibitors (CD3)

Histone lysine-specific demethylase 1 (LSD1) is hyperactive in breast cancer, which is associated with the metastasis of the tumor. Current irreversible LSD1 inhibitors are all synthesized by covalently binding to the flavin adenine dinucleotide cofactor, which often have side effects due to the high affinity for a variety of targets. Here, we identified isoforsythiaside (IFA), a natural phenylpropanoid glycoside isolated from Forsythia suspensa, as a novel covalent inhibitor of LSD1. The target ligand fishing technique and LC-MS/MS analysis identified that IFA could covalently bind to the Ser817 residue of LSD1 by α,β-unsaturated ketone moiety to block the amine oxidase-like domain of LSD1. Moreover, RBMS3/Twist1/MMP2, the downstream signaling pathway of LSD1, was activated after IFA treatment to inhibit the metastasis of MDA-MB-231 cells in vitro and in vivo. This study provided novel molecular templates for development of LSD1 covalence-binding inhibitor and laid a foundation for developing agents against breast carcinoma metastasis for targeting LSD1.

Liver fibrosis is characterized by excessive deposition of extracellular matrix due to chronic inflammation of the liver. Hepatic stellate cells (HSCs) become activated and produce excessive amounts of extracellular matrix. It was previously shown that loss of HIF-prolyl-hydroxylase 1 (PHD1) attenuates HSC activation and fibrotic tissue remodeling in a murine model of biliary liver fibrosis. Thus, the protective effect of PHD1 deficiency (PHD1^-/-) in an additional (toxic) model of liver fibrosis was validated and the effect of dimethyloxalylglycine (DMOG), a pan-HIF-prolyl-hydroxylase inhibitor, on the development of liver fibrosis, was evaluated. Liver fibrosis was induced utilizing carbon tetrachloride in wild-type (WT), PHD1^-/-, vehicle-treated, and DMOG-treated mice. Livers were further analyzed by Sirius red staining and gene expression analysis of profibrotic genes to assess fibrosis development. When compared with WT mice, PHD1^-/- mice developed less-severe liver fibrosis. By contrast, DMOG treatment did not prevent liver fibrosis. PHD1^-/- mice showed fewer α-SMA⁺ cells and less macrophage infiltration compared with WT mice. Gene expression of profibrogenic and proinflammatory genes was reduced in livers from carbon tetrachloride-exposed PHD1^-/- mice. In vitro analyses of PHD1-deficient human HSCs revealed attenuated mRNA levels of profibrotic genes, as well as impaired migration and invasion. Although PHD1 deficiency attenuates activation of HSCs, pharmacologic PHD inhibition does not ameliorate fibrosis development. Selective PHD1 inhibitors could prove effective in preventing and treating liver fibrosis.