Tubeimoside-1 induces TFEB-dependent lysosomal degradation of PD-L1 and promotes antitumor immunity by targeting mTOR

Programmed cell death ligand 1 (PD-L1)/programmed cell death protein 1 (PD-1) cascade is an effective therapeutic target for immune checkpoint blockade (ICB) therapy. Targeting PD-L1/PD-1 axis by small-molecule drug is an attractive approach to enhance antitumor immunity. Using flow cytometry-based assay, we identify tubeimoside-1 (TBM-1) as a promising antitumor immune modulator that negatively regulates PD-L1 level. TBM-1 disrupts PD-1/PD-L1 interaction and enhances the cytotoxicity of T cells toward cancer cells through decreasing the abundance of PD-L1. Furthermore, TBM-1 exerts its antitumor effect in mice bearing Lewis lung carcinoma (LLC) and B16 melanoma tumor xenograft

Dual roles of p62/SQSTM1 in the injury and recovery phases of acetaminophen-induced liver injury in mice

Acetaminophen (APAP) overdose can induce liver injury and is the most frequent cause of acute liver failure in the United States. We investigated the role of p62/SQSTM1 (referred to as p62) in APAP-induced liver injury (AILI) in mice. We found that the hepatic protein levels of p62 dramatically increased at 24 h after APAP treatment, which was inversely correlated with the hepatic levels of APAP-adducts. APAP also activated mTOR at 24 h, which is associated with increased cell proliferation. In contrast, p62 knockout (KO) mice showed increased hepatic levels of APAP-adducts detected by a specific antibody using Western blot analysis but decreased mTOR activation and cell proliferation with aggravated liver injury at 24 h after APAP treatment. Surprisingly, p62 KO mice recovered from AILI whereas the wild-type mice still sustained liver injury at 48 h. We found increased number of infiltrated macrophages in p62 KO mice that were accompanied with decreased hepatic von Willebrand factor (VWF) and platelet aggregation, which are associated with increased cell proliferation and improved liver injury at 48 h after APAP treatment. Our data indicate that p62 inhibits the late injury phase of AILI by increasing autophagic selective removal of APAP-adducts and mitochondria but impairs the recovery phase of AILI likely by enhancing hepatic blood coagulation.

Inhibition of LIM kinase reduces contraction and proliferation in bladder smooth muscle

Overactive bladder (OAB) is the most bothersome symptom in lower urinary tract symptoms (LUTS). Current pharmacologic treatment aims to inhibit detrusor contraction; however, shows unsatisfied efficacy and high discontinuation rate. LIM kinases (LIMKs) promote smooth muscle contraction in the prostate; however, their function in the bladder smooth muscle remains unclear. Here, we studied effects of the LIMK inhibitors on bladder smooth muscle contraction and proliferation both

Analysis on Role of mTORC1/4E-BP1 Axis in Idiopathic Pulmonary Fibrosis and Research Progress of Bupleuri Radix on Its Intervention / 中国实验方剂学杂志

Idiopathic pulmonary fibrosis （IPF） is a common， lethal interstitial lung disease characterized by airway remodeling， inflammation， alveolar destruction， and fibrosis. The mammalian target of rapamycin complex 1/4E binding protein 1 （mTORC1/4E-BP1） axis is closely related to the expression of collagen by fibroblasts， and its role in pulmonary fibrosis remains to be further elucidated. Traditional Chinese medicine （TCM） has shown promising efficacy in improving the lung function， exercise capacity， and quality of life in patients with IPF. The theory of "same treatment for different diseases" provides a TCM theoretical basis for the treatment of pulmonary fibrosis with Bupleuri Radix， while the research in western medicine has preliminarily shown that both the formulation and single herb as well as the active ingredients of Bupleuri Radix have good therapeutic effects on pulmonary fibrosis. Therefore， this review will elaborate on the role of the mTORC1/4E-BP1 axis in the pathomechanism of IPF， as well as the research results of the active components of Bupleuri Radix on the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin protein（PI3K/AKT/mTOR） pathway， so as to provide a reference for the treatment and drug development of IPF.

Everolimus together with AR-A014418 induces apoptosis of A375 melanoma cells / 中华皮肤科杂志

Objective To evaluate effects of simultaneous inhibition of mammalian target of rapamycin complex 1(mTORC1)kinase and glycogen synthase kinase-3β(GSK-3β)on phosphorylation of 4E-binding protein-1(4EBP1), cap-dependent translation, as well as survival and apoptosis of melanoma cells. Methods Cultured A375 cells were classified into several groups to be treated with dimethyl sulfoxide (DMSO group), the mTORC1 kinase inhibitor everolimus at a concentration of 5 nmol/L (everolimus group), the GSK-3β kinase inhibitor AR-A014418 at a concentration of 10 μmol/L (AR-A014418 group), or 5 nmol/L everolimus and 10 μmol/L AR-A014418(combined treatment group). After additional culture, Western-blot analysis was performed to measure protein expressions of phosphorylated 4EBP1 (p4EBP1)and survivin in A375 cells, m7GTP pull down assay to estimate interaction between eukaryotic initiation factor-4E (eIF4E)and eIF4G, cell counting kit 8 (CCK8)assay to evaluate cell proliferation, and flow cytometry to detect cell apoptosis. Results Both everolimus and AR-A014418 had inhibitory effects on 4EBP1 phosphorylation and survivin expression. The expressions of p4EBP1-65 and survivin were both significantly decreased in the everolimus group (0.74 ± 0.05 and 0.71 ± 0.06 respectively), AR-A014418 group (0.62 ± 0.06 and 0.58 ± 0.07 respectively)and combined treatment group (0.14 ± 0.04 and 0.09 ± 0.05 respectively)compared with the DMSO group (1.00 ± 0.07 and 1.00 ± 0.06, respectively, all P < 0.001), with the most significant decrease observed in the combined treatment group. As m7GTP pull-down assay showed, the everolimus group, AR-A014418 group and combined treatment group all showed significantly lower relative expression levels of eIF4G(0.72 ± 0.04, 0.67 ± 0.05 and 0.12 ± 0.05 vs. 1.00 ± 0.06, all P < 0.001), but significantly higher relative expression levels of 4EBP1 (1.98 ± 0.16, 2.32 ± 0.17 and 7.58 ± 0.25 vs. 1.00 ± 0.08, all P < 0.001)than the DMSO group, and the combined treatment group showed the lowest eIF4G expression but highest 4EBP1 expression. After 24-hour culture, the proliferation of A375 cells was inhibited by 18.5% ± 1.3% in the everolimus group, 19.8% ± 1.8% in the AR-A014418 group, and 61.2% ± 2.1% in the combined treatment group compared with the DMSO group, with the strongest inhibition noted in the combined treatment group. The inhibitory effects of everolimus and AR-A014418 on cell proliferation increased over time, and showed the same trend at 48 hours. Flow cytometry showed that the apoptosis of A375 cells was accelerated by the 24-hour treatments with everolimus and AR-A014418 alone or in combination, with the apoptosis rate being 14.28% ± 2.18%, 14.57% ± 2.35% and 55.18% ± 6.27% in the everolimus group, AR-A014418 group and combined treatment group respectively, and the combined treatment showed the strongest accelerating effect. Conclusion The combined treatment with everolimus and AR-A014418 can evidently inhibit 4EBP1 phosphorylation and eIF4F complex formation in A375 cells, which then suppress cap-dependent translation and promote apoptosis of melanoma cells.

Expression of phosphorylated mammalian target of rapamycin (p-mTOR) and phosphorylated eukaryotic translation initiation factor 4E binding protein 1 in pathologic scar / 中华医学美学美容杂志

Objective To investigate the expression of phosphorylated mammalian target of rapamycin (p-mTOR) and phosphorylated eukaryotic translation initiation factor 4E binding protein 1 (p-4EBP1) in pathologic scar,and comprehend its role and significance in the pathologic scar formation.Methods SP immunohistochemical method was used to detect the expression of p-mTOR and p-4EBP1 in 20 cases of keloid,20 cases of hypertrophic scar,20 cases of non-pathologic scar and 20 cases of normal skin tissue.The positive rates of expression in different tissues were analyzed,and the relationship in pathological scar was explored.Results The positive rates of p-mTOR and p-4EBP1 in keloidand hypertrophic scar were 75.0％ (15/20),60.0％ (12/20) and 60.0％ (12/20),50.0％ (10/20),nom-pathologic scars were 20％ (4/20),10％ (2/20);normal skin tissue were 10％ (2/20),5％ (1/20),which were higher respectively compared with the two control groups (P＜ 0.05);there was a highly positive correlation between p-mTOR and p-4EBP1 expression in pathologic scar (r=0.323,P＜0.05).Conclusions p-mTOR and p-4EBP1 might be involved and cooperated in promoting the progress of pathologic scars.