Human carboxylesterase 2A (hCES2A) plays pivotal roles in prodrug activation and hydrolytic metabolism of ester-bearing chemicals. Targeted inhibition of intestinal hCES2A represents a feasible strategy to mitigate irinotecan-triggered gut toxicity (ITGT), but the orally active, selective, and efficacious hCES2A inhibitors are rarely reported. Here, a novel drug-like hCES2A inhibitor was developed via three rounds of structure-based drug design (SBDD) and structural optimization. Initially, donepezil was identified as a moderate hCES2A inhibitor from 2000 US Food and Drug Administration (FDA)-approved drugs. Following two rounds of SBDD and structural optimization, a donepezil derivative (B7) was identified as a strong reversible hCES2A inhibitor. Subsequently, nine B7 carbamates were rationally designed, synthesized and biologically assayed. Among all synthesized carbamates, C3 showed the most potent time-dependent inhibition on hCES2A (IC₅₀ = 0.56 nmol/L), excellent specificity and favorable drug-like properties. C3 could covalently modify the catalytic serine of hCES2A with high selectivity, while this agent also showed favorable safety profiles, high intestinal exposure, and impressive effects for ameliorating ITGT in both human intestinal organoids and tumor-bearing mice. Collectively, this study showcases a rational strategy for developing drug-like and serine-targeting covalent inhibitors against target serine hydrolase(s), while C3 emerges as a promising orally active drug candidate for ameliorating ITGT.

Objective To investigate whether decursin(Dec) could inhibit EC109 cells proliferation by suppression of janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway in human esophageal squamous cell carcinoma.Methods The EC109 cells were treated with Dec(20,40,and 80 pmmol/L) for48 h.The cell viability was evaluated by MTT;the apoptotic cells was labelled by TUNEL;the mitochondrial oxidative stress level was detected by fluorescent staining;and western blotting was used to analyze the proteins of JAK2/STAT3 signaling and apoptosis in EC109 cells,respectively.After co-application of JAK2 / STAT3 antagonist(AG490),the inhibitory ability of Dec to EC109 was observed from the in vivo and in vitro levels.Results Compared to the control group,different concentrations of Dec dose-dependently down-regulated expressions of p-JAK2 [(55.89 ± 6.04) ％] and p-STAT3 [(45.27 ± 8.65) ％],repressed EC109 cell activity(0.43 ± 0.078),increased apoptotic rate[(35.31 ± 8.41)％],reduced MMP levels[(37.23 ± 6.89)％],promoted reactive oxygen species(ROS) [(231.81 ± 19.63)％],decreased glutathione (GSH) activity [(46.78 ± 6.91)％,P＜0.05].However,Dec did not significantly affect the activity of the normal esophageal epithelium HET-1A cells(P ＞0.05).Meanwhile,Dec obviously leaded to reduction of Bcl2,increment of Bax,and augment of Caspase-3 cleavage (P ＜0.05).Additionally,the inhibitory effect of Dec on EC109 was specifically intensified after co-application of AG490 in vivo and in vitro levels(P ＜0.05).Conclusion Dec can fight against human esophageal squamous cell carcinoma in vitro and in vivo via activation of mitochondrial oxidative stress-induced apoptosis which was mediated by JAK2/STAT3 pathway.

Objective To investigate the changes of cortical thickness and relative resting state functional connectivity in patients with generalized anxiety disorder (GAD).Methods The present study analyzed structural and eyes-open resting state functional MRI were performed in 21 patients with GAD and 22 matched healthy controls.Cortical thickness was estimated with FreeSurfer.The structurally altered regions were defined as region of interest (ROI) to analyze functional connectivity (FC) using resting state functional MRI data by DPABI.Results Cortical thickness of patients with GAD were increased in right rostral middle frontal gyrus (rMFG;MNI:x =27.9,y =53.4,z =-11.1;size:241.93 mm2;FDR corrected,P ＜ 0.1) and right inferior temporal gyrus (IGT;MNI:x =49.7,y =-57.8,z =-8.7;size:138.93 mm2;FDR corrected,P＜0.1) compared with healthy controls.FC between right rMFG and right superior/middle occipital gyrus as well as well as FC between rMFG and right precentral gyrus showed decreased in patients with GAD compared with healthy controls(AlphaSim corrected,P＜0.05).FC between right rMFG and right angular gyrus showed increased in patients with GAD compared with healthy control (AlphaSim corrected,P＜0.05).Conclusion The rMFG may play an important role in the pathophysiology of GAD,which can be used as an stimuli target in physicotherapeutics to improve anxiety symptoms.