Phenothiazine-Based LSD1 Inhibitor Promotes T-Cell Killing Response of Gastric Cancer Cells.

Histone lysine specific demethylase 1 (LSD1) has been recognized as an important epigenetic target for cancer treatment. Although several LSD1 inhibitors have entered clinical trials, the discovery of novel potent LSD1 inhibitors remains a challenge. In this study, the antipsychotic drug chlorpromazine was characterized as an LSD1 inhibitor (IC50 = 5.135 µM), and a series of chlorpromazine derivatives were synthesized. Among them, compound 3s (IC50 = 0.247 µM) was the most potent one. More importantly, compound 3s inhibited LSD1 in the cellular level and downregulated the expression of programmed cell death-ligand 1 (PD-L1) in BGC-823 and MFC cells to enhance T-cell killing response. An in vivo study confirmed that compound 3s can inhibit MFC cell proliferation without significant toxicity in immunocompetent mice. Taken together, our findings indicated that the novel LSD1 inhibitor 3s tethering a phenothiazine scaffold may serve as a lead compound for further development to activate T-cell immunity in gastric cancer.

Discovery of cinnamamide-barbiturate hybrids as a novel class of Nrf2 activator against myocardial ischemia/reperfusion injury.

Myocardial ischemia/reperfusion (MI/R) has been a challenge for global public health. Activation of nuclear factor erythroid-2-related factor 2 (Nrf2) signaling could attenuate MI/R injury by maintaining cell redox balance and reducing oxidative damage. Cinnamamide derivatives have been proven to be a class of potential Nrf2 activators and cardioprotective agents. The development of novel cinnamamide derivatives to combat oxidative stress in cardiomyocytes is highly desirable. In this study, twenty-three cinnamamide-barbiturate hybrids were studied. Cell-based assays showed that most of the compounds exhibited excellent protective activity against H2O2-induced oxidative injury in H9c2 cells. Notably, compound 7w, which had the highest activity and low cytotoxicity, was demonstrated to remarkably reduce intracellular ROS accumulation by activating the mRNA expression of Nrf2 and its downstream antioxidant gene HO-1, indicating a novel promising antioxidant and Nrf2 activator. The probable binding mode between protein Keap1 and compound 7w was also studied via molecule docking. Furthermore, we found that the administration of compound 7w could significantly reduce the cardiac infarct size and improve the cardiac function against MI/R injury in rats, as well as decrease cardiac oxidative stress. Taken together, we report, for the first time, that cinnamamide-barbiturate hybrids are a novel class of potential cardioprotective agents. The excellent cardioprotective action of such compounds rely on enhancing the endogenous antioxidative system by upregulating the Nrf2 signaling pathway in vitro and in vivo against MI/R damage. These findings provide a new perspective for designing cinnamamide-barbiturate hybrids as a novel class of Nrf2 activator against cardiovascular diseases.