Hydnocarpin inhibits malignant progression of triple negative breast cancer via CNOT4-mediated ubiquitination and degradation of YAP / 中国中药杂志

This study aims to investigate the effect and mechanism of hydnocarpin(HC) in treating triple negative breast cancer(TNBC). Cell counting kit-8(CCK-8), xCELLigence real-time cellular analysis(RTCA), and colony formation assay were employed to determine the effects of HC on the proliferation of two TNBC cell lines: MDA-MB-231 and MDA-MB-436. The effects of HC on the migration and invasion of TNBC cells were detected by high-content analysis, wound-healing assay, and Transwell assay. The changes in the epithelial-mesenchymal transition(EMT) and the expression of invasion-and migration-associated proteins [E-cadherin, vimentin, Snail, matrix metalloproteinase-2(MMP-2), and MMP-9] were detected by Western blot. Western blot and RT-qPCR were employed to determine the protein and mRNA levels of Yes-associated protein(YAP) and downstream targets(CTGF and Cyr61). TNBC cells were transfected with Flag-YAP for the overexpression of YAP, and the role of YAP as a key target for HC to inhibit TNBC malignant progression was examined by CCK-8 assay, Transwell assay, and wound-healing assay. The pathway of HC-induced YAP degradation was detected by the co-treatment of proteasome inhibitor with HC and ubiquitination assay. The binding of HC to YAP and the E3 ubiquitin ligase Ccr4-not transcription complex subunit 4(CNOT4) was detected by microscale thermophoresis(MST) assay and drug affinity responsive target stability(DARTS) assay. The results showed that HC significantly inhibited the proliferation, colony formation, invasion, and EMT of TNBC cells. HC down-regulated the protein and mRNA levels of CTGF and Cyr61. HC down-regulated the total protein level of YAP, while it had no effect on the mRNA level of YAP. The overexpression of YAP antagonized the inhibitory effects of HC on the proliferation, migration, and invasion of TNBC cells. HC promoted the degradation of YAP through the proteasome pathway and up-regulated the ubiquitination level of YAP. The results of MST and DARTS demonstrated direct binding between HC, YAP, and CNOT4. The above results indicated that HC inhibited the malignant progression of TNBC via CNOT4-mediated degradation and ubiquitination of YAP.

Mechanism of polyphyllin A in inhibition of proliferation and induction of apoptosis of gastric cancer cells by directly targeting ETS-1 / 中国中药杂志

The present study investigated the mechanism of polyphyllin A(PPA) in inhibiting gastric cancer(GC) cells. GC cells(SGC7901 and MGC803 cell lines) were treated with PPA at different concentrations. The effect of PPA on the proliferation of GC cells was detected by MTT assay, real-time cell analysis(RTCA) assay, and clone-forming assay, respectively. Reactive oxygen species(ROS) of GC cells was detected by flow cytometry. The change of mitochondrial membrane potential was detected by JC-1 assay. The expression and phosphorylation levels of apoptosis-related proteins(caspase-9, caspase-3, and PARP) and proteins related to the signaling pathway(ETS-1, CIP2 A, and Akt) were detected by Western blot. The binding sites of PPA to ETS-1 were analyzed by molecular docking. The affinity of PPA and ETS-1 was detected by drug affinity responsive target stability(DARTS) assay. PPA had a significant inhibitory effect on the proliferation and colony formation of GC cells at a low concentration. The PPA groups showed increased ROS and decreased mitochondrial membrane potential. PPA down-regulated the precursor expression of caspase-9 and caspase-3 and promoted the cleavage of PARP, suggesting that PPA induced the apoptosis of GC cells through the mitochondrial pathway. PPA significantly reduced expression levels of CIP2 A and the phosphorylation of downstream Akt. Molecular docking showed that PPA bound to the ETS domain of ETS-1, the transcription factor of CIP2 A, and formed hydrogen bonds with Pro319 and Asp317. DARTS assay further confirmed that PPA significantly prevented the hydrolysis of ETS-1 by pronase, which was inductive of the direct binding effect of PPA and ETS-1. PPA inhibits the proliferation and induces the apoptosis of GC cells by directly targeting ETS-1 to down-regulate the ETS-1/CIP2 A/Akt signaling pathway.