Aloperine Suppresses Cancer Progression by Interacting with VPS4A to Inhibit Autophagosome-lysosome Fusion in NSCLC.

Aloperine (ALO), a quinolizidine-type alkaloid isolated from a natural Chinese herb, has shown promising antitumor effects. Nevertheless, its common mechanism of action and specific target remain elusive. Here, it is demonstrated that ALO inhibits the proliferation and migration of non-small cell lung cancer cell lines in vitro and the tumor development in several mouse tumor models in vivo. Mechanistically, ALO inhibits the fusion of autophagosomes with lysosomes and the autophagic flux, leading to the accumulation of sequestosome-1 (SQSTM1) and production of reactive oxygen species (ROS), thereby inducing tumor cell apoptosis and preventing tumor growth. Knockdown of SQSTM1 in cells inhibits ROS production and reverses ALO-induced cell apoptosis. Furthermore, VPS4A is identified as a direct target of ALO, and the amino acids F153 and D263 of VPS4A are confirmed as the binding sites for ALO. Knockout of VPS4A in H1299 cells demonstrates a similar biological effect as ALO treatment. Additionally, ALO enhances the efficacy of the anti-PD-L1/TGF-ß bispecific antibody in inhibiting LLC-derived subcutaneous tumor models. Thus, ALO is first identified as a novel late-stage autophagy inhibitor that triggers tumor cell death by targeting VPS4A.

Design, synthesis and biological evaluation of aloperine derivatives as potential anticancer agents.

Modifications at different positions on the aloperine molecule were performed to improve its anticancer activity and develop anticancer drugs. The in vitro anticancer activities of 44 synthesized compounds were evaluated. The effect of modification positions on anticancer activity was discussed and a structure-activity relationship analysis was established. A novel series of compounds with modifications at the N12 position showed much higher cytotoxicity than aloperine. Among them, compound 22 displayed promising in vitro anticancer activity against PC9 cells with a median inhibitory concentration (IC50) of 1.43 µM. The mechanism studies indicated that compound 22 induced cell apoptosis and cell cycle arrest in PC9 cells. These results demonstrate the potential of aloperine thiourea derivatives in anticancer activity.

[Aloperine suppresses TLR4/NF-κB/NLRP3 signaling to ameliorate cigarette smoke-induced injury to human bronchial epithelial cells].

Objective To explore the effects of aloperine (Alo) on cigarette smoke-induced injury in human bronchial epithelial cells and its potential mechanism. Methods After human bronchial epithelial 16HBE cells were co-treated by 100 mL/L cigarette smoke extract (CSE) and various concentrations (50,100 and 200 µmol/L) of Alo, cell viability was assessed using CCK-8 assay. Lactate dehydrogenase (LDH) activity was measured with a related kit. Cell apoptosis was evaluated using the terminal-deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL) and Western blot analysis. The levels of inflammatory factors were detected by ELISA. Oxidative stress levels were assessed using 2'7'-dichlorofluorescin diacetate (DCFH-DA) staining. The expression of Toll-like receptor 4 (TLR4)/nuclear factor-kappaB (NF-κB)/NLR family pyrin domain containing 3 (NLRP3) signaling-associated proteins was measured by Western blot analysis. After cells were co-treated with 100 mL/L CSE and 200 µmol/L Alo, the aforementioned assays were applied to evaluate the effects of TLR4 overexpression on the TLR4/NF-κB/NLRP3 signaling, LDH activity, apoptosis, inflammatory response and oxidative stress in cells. Results CSE exposure might inhibit 16HBE cell viability, increase LDH activity, apoptosis, inflammatory response and oxidative stress levels and activate TLR4/NF-κB/NLRP3 signaling. Treatment with Alo promoted cell viability, decreased LDH activity, cell apoptosis, inflammation and oxidative stress levels, and inactivated TLR4/NF-κB/NLRP3 signaling. Furthermore, TLR4 overexpression might reverse the protective role of Alo treatment in CSE-induced injury in 16HBE cells. Conclusion Alo may ameliorate CSE-induced injury in human bronchial epithelial cells via inhibiting TLR4/NF-κB/NLRP3 signaling.