CCT020312 exerts anti-prostate cancer effect by inducing G1 cell cycle arrest, apoptosis and autophagy through activation of PERK/eIF2α/ATF4/CHOP signaling.

PERK/eIF2α/ATF4/CHOP signaling pathway is one of three major branches of unfolded protein response (UPR) and has been implicated in tumor progression. CCT020312 is a selective PERK activator and may have a potential anti-tumor effect. Here we investigated the anti-prostate cancer effect and its underlying mechanism of CCT020312. Our results showed that CCT020312 inhibited prostate cancer cell viability by inducing cell cycle arrest, apoptosis and autophagy through activation of PERK/eIF2α/ATF4/CHOP signaling. CCT020312 treatment caused cell cycle arrest at G1 phase and increased the levels of cleaved-Caspase3, cleaved-PARP and Bax in prostate cancer C4-2 and LNCaP cells. Moreover, CCT020312 increased LC3II/I, Atg12-Atg5 and Beclin1 levels and induced autophagosome formation. Furthermore, knockdown of CHOP reversed CCT020312-induced cell viability decrease, apoptosis and autophagy. Bafilomycin A1 reversed CCT020312-induced cell viability decrease but had no effect on CCT020312-induced CHOP activation in C4-2 and LNCaP cells. In vivo, CCT020312 suppressed tumor growth in C4-2 cells-derived xenograft mouse model, activated PERK pathway, and induced autophagy and apoptosis. Our study illustrates that CCT020312 exerts an anti-tumor effect in prostate cancer via activating the PERK pathway, thus indicating that CCT020312 may be a potential drug for prostate cancer.

N76-1, a novel CDK7 inhibitor, exhibits potent anti-cancer effects in triple negative breast cancer.

Emerging evidence suggests that genetically highly specific triple-negative breast cancer (TNBC) possesses a relatively uniform transcriptional program that is abnormally dependent on cyclin-dependent kinase 7 (CDK7). In this study, we obtained an inhibitor of CDK7, N76-1, by attaching the side chain of the covalent CDK7 inhibitor THZ1 to the core of the anaplastic lymphoma kinase inhibitor ceritinib. This study aimed to elucidate the role and underlying mechanism of N76-1 in TNBC and evaluate its potential value as an anti-TNBC drug. The results of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony formation assays showed that N76-1 inhibited the viability of TNBC cells. Kinase activity and cellular thermal shift assays showed that N76-1 directly targeted CDK7. Flow cytometry results revealed that N76-1 induced apoptosis and cell cycle arrest in the G2/M phase. N76-1 also effectively inhibited the migration of TNBC cells by high-content detection. The RNA-seq analysis showed that the transcription of genes, especially those related to transcriptional regulation and cell cycle, was suppressed after N76-1 treatment. Moreover, N76-1 markedly inhibited the growth of TNBC xenografts and phosphorylation of RNAPII in tumor tissues. In summary, N76-1 exerts potent anticancer effects in TNBC by inhibiting CDK7 and provides a new strategy and research basis for the development of new drugs for TNBC.

VPS34-IN1 induces apoptosis of ER+ breast cancer cells via activating PERK/ATF4/CHOP pathway.

VPS34-IN1 is a specific selective inhibitor of Class III Phosphatidylinositol 3-kinase (PI3K) and has been shown to exhibit a significant antitumor effect in leukemia and liver cancer. In current study, we focused on the anticancer effect and potential mechanism of VPS34-IN1 in estrogen receptor positive (ER+ ) breast cancer. Our results revealed that VPS34-IN1 inhibited the viability of ER+ breast cancer cells in vitro and in vivo. Flow cytometry and western blot analyses showed that VPS34-IN1 treatment induced breast cancer cell apopotosis. Interestingly, VPS34-IN1 treatment activated protein kinase R (PKR)-like ER kinase (PERK) branch of endoplasmic reticulum (ER) stress. Furthermore, knockdown of PERK by siRNA or inhibition of PERK activity by chemical inhibitor GSK2656157 could attenuate VPS34-IN1-mediated apoptosis in ER+ breast cancer cells. Collectively, VPS34-IN1 has an antitumor effect in breast cancer, and it may result from activating PERK/ATF4/CHOP pathway of ER stress to induce cell apoptosis. These findings broaden our understanding of the anti-breast cancer effects and mechanisms of VPS34-IN1 and provide new ideas and reference directions for the treatment of ER+ breast cancer.

Celastrol targets the ChREBP-TXNIP axis to ameliorates type 2 diabetes mellitus.

BACKGROUNDS: Thioredoxin-interacting protein (TXNIP) plays a pivotal role in regulation of blood glucose homeostasis and is an emerging therapeutic target in diabetes and its complications. Celastrol, a pentacyclic triterpene extracted from the roots of Tripterygium wilfordii Hook F, can reduce insulin resistance and improve diabetic complications. PURPOSE: This study aimed to untangle the mechanism of celastrol in ameliorating type 2 diabetes (T2DM) and evaluate its potential benefits as an anti-diabetic agent. METHODS: db/db mice was used to evaluate the hypoglycemic effect of celastrol in vivo; Enzyme-linked immunosorbent assay (ELISA) and 2-NBDG assay were used to detect the effect of celastrol on insulin secretion and glucose uptake in cells; Western blotting, quantitative reverse transcription PCR (RT-qPCR) and immunohistological staining were used to examine effect of celastrol on the expression of TXNIP and the carbohydrate response element-binding protein (ChREBP). Molecular docking, cellular thermal shift assay (CETSA), drug affinity responsive targets stability assay (DARTS) and mass spectrometry were used to test the direct binding between celastrol and ChREBP. Loss- and gain-of-function studies further confirmed the role of ChREBP and TXNIP in celastrol-mediated amelioration of T2DM. RESULTS: Celastrol treatment significantly reduced blood glucose level, body weight and food intake, and improved glucose tolerance in db/db mice. Moreover, celastrol promoted insulin secretion and improved glucose homeostasis. Mechanistically, celastrol directly bound to ChREBP, a primary transcriptional factor upregulating TXNIP expression. By binding to ChREBP, celastrol inhibited its nuclear translocation and promoted its proteasomal degradation, thereby repressing TXNIP transcription and ultimately ameliorating T2DM through breaking the vicious cycle of hyperglycemia deterioration and TXNIP overexpression. CONCLUSION: Celastrol ameliorates T2DM through targeting ChREBP-TXNIP aix. Our study identified ChREBP as a new direct molecular target of celastrol and revealed a novel mechanism for celastrol-mediated amelioration of T2DM, which provides experimental evidence for its possible use in the treatment of T2DM and new insight into diabetes drug development for targeting TXNIP.

Quercetin Suppresses Human Glioblastoma Migration and Invasion via GSK3ß/ß-catenin/ZEB1 Signaling Pathway.

High invasiveness is a biological and clinical characteristic of glioblastoma and predicts poor prognosis of patients. Quercetin, a natural flavonoid compound, exhibits anticancer activity. However, we have a limited understanding of the possible underlying mechanism of quercetin in glioblastoma. In this study, we investigated the anticancer effect of quercetin in human glioblastoma cells. Our results showed that quercetin markedly suppressed the viability of glioblastoma cells in vitro and in vivo, and significantly inhibited glioblastoma cell migration and invasion. Moreover, quercetin reversed EMT-like mesenchymal phenotype and reduced the expression levels of EMT-related markers. Furthermore, we found that quercetin suppressed GSK-3ß/ß-catenin/ZEB1 signaling in glioblastoma. Taken together, our results demonstrate that quercetin inhibited migration and invasion of human glioma cells by suppressing GSK3ß/ß-catenin/ZEB1 signaling. Our study provides evidence that quercetin is a promising therapeutic natural compound to treat glioblastoma.

Co-Crystal of Rosiglitazone With Berberine Ameliorates Hyperglycemia and Insulin Resistance Through the PI3K/AKT/TXNIP Pathway In Vivo and In Vitro.

Background: Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease characterized by insulin resistance and hyperglycemia. This study examined the effect and elucidated the mechanism of improvement of hyperglycemia and insulin resistance by a co-crystal of rosiglitazone with berberine (RB) in high-sugar high-fat diet (HSHFD)-induced diabetic KKAy mice. Methods: Diabetic KKAy mice were randomly divided into seven groups: KKAy model control group (DM control) treated with 3% sodium carboxymethyl cellulose; RB groups, administered daily with RB 0.7 mg/kg (RB-L), 2.11 mg/kg (RB-M), or 6.33 mg/kg (RB-H); positive control groups, administered daily with rosiglitazone 1.04 mg/kg (RSG), berberine 195 mg/kg (BBR), or combination of 1.04 mg/kg RSG and 1.08 mg/kg BBR (MIX). Test compounds were administered orally for 8 weeks. Non-diabetic C57BL/6J mice were used as normal control (NC). Blood glucose, food intake, body weight, glucose-lipid metabolism, and pathological changes in the pancreas and liver were examined. We further evaluated the mechanism of action of RB in C2C12 and HepG2 cells stimulated with high glucose and palmitate. Results: RB treatment improved glucolipid metabolism and insulin resistance in diabetic KKAy mice. RB reduced blood glucose levels, white fat index, plasma triglyceride (TG), low-density lipoprotein (LDL), gastric inhibitory peptide (GIP), and insulin levels, increased the levels of plasma glucagon-like peptide-1 (GLP-1), high-density lipoprotein (HDL), and glycogen content in the liver and muscle; and improved oral glucose tolerance test (OGTT), insulin tolerance test (ITT), and pathological changes in the pancreas and liver of KKAy mice. Moreover, RB upregulated p-PI3K and p-AKT levels and reduced TXNIP expression in KKAy mice and in HepG2 and C2C12 cells. Conclusion: These data indicate that RB ameliorates insulin resistance and metabolic disorders, and the mechanism might be through regulating the PI3K/AKT/TXNIP signaling pathway . Thus, the co-crystal drug RB may be considered as a potential antidiabetic agent for future clinical therapy.