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.

Screening of and mechanism underlying the action of serum- and glucocorticoid-regulated kinase 3-targeted drugs against estrogen receptor-positive breast cancer.

Breast cancer is the most common cancer in women. Serum and glucocorticoid-regulated kinase 3 (SGK3) promotes the progression and drug resistance of estrogen receptor-positive (ER+) breast cancer. Therefore, SGK3 is a promising therapeutic target for the treatment of ER + breast cancer. In this study, we used computer-aided drug discovery/design to perform a virtual screening of SGK3 inhibitors from the ZINC database. The results of MTT assay, real-time cell proliferation analysis, colony formation assay, transwell migration assay, and orthotopic implantation model show that Zinc-09 inhibited the proliferation and migration of ER + breast cancer cells in vivo and in vitro. Furthermore, Zinc-09 decreased SGK3 expression, and knockdown of SGK3 by siRNA reversed the inhibitory effect of Zinc-09 in MCF-7 cells. Moreover, Zinc-09 treatment induced G1 phase arrest and autophagic cell death. Taken together, Zinc-09 can suppress ER + breast cancer. This study provides an experimental and theoretical basis for the research and development of new anti-ER + breast cancer drugs.

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.

Endoplasmic reticulum stress inhibits AR expression via the PERK/eIF2α/ATF4 pathway in luminal androgen receptor triple-negative breast cancer and prostate cancer.

Androgen receptor (AR) is an important prognostic marker and therapeutic target in luminal androgen receptor triple-negative breast cancer (LAR TNBC) and prostate cancer (PCa). Endoplasmic reticulum (ER) stress may activate the unfolded protein response (UPR) to regulate associated protein expression and is closely related to tumor growth and drug resistance. The effect of ER stress on AR expression and signaling remains unclear. Here, we focused on the regulation and underlying mechanism of AR expression induced by ER stress in LAR TNBC and PCa. Western blotting and quantitative RT-PCR results showed that AR expression was markedly decreased under ER stress induced by thapsigargin and brefeldin A, and this effect was dependent on PERK/eIF2α/ATF4 signaling activation. Chromatin immunoprecipitation-PCR and luciferase reporter gene analysis results showed that ATF4 bound to the AR promoter regions to inhibit its activity. Moreover, ATF4 overexpression inhibited tumor proliferation and AR expression both in vitro and in vivo. Collectively, these results demonstrated that ER stress could decrease AR mRNA and protein levels via PERK/eIF2α/ATF4 signaling in LAR TNBC and PCa. Targeting the UPR may be a treatment strategy for AR-dependent TNBC and PCa.

Qihu Preparation Ameliorates Diabetes by Activating the AMPK Signaling Pathway in db/db Mice.

PURPOSE: To examine the pharmacological effects of Qihu on type 2 diabetes mellitus using db/db mice. MATERIALS AND METHODS: Thirty-seven db/db mice were randomly divided into the following 5 groups: diabetes model control group (DM group; n = 7), administered with the adjuvant 0.3% carboxymethyl cellulose-Na; positive control group (Met group; n = 8), administered with metformin (0.13 g/kg bodyweight); Qihu-L group (n = 7), administered with a low dose of Qihu (0.75 g/kg bodyweight), Qihu-M group (n = 7), administered with a medium dose of Qihu (1.5 g/kg bodyweight); Qihu-H group (n = 8), administered with a high dose of Qihu (3.0 g/kg bodyweight). BKS mice (n = 8) were used as the negative control group. The db/db mice were administered with drugs through oral gavage for 28 days. The random blood glucose levels, glucose tolerance test, bodyweight, food intake, and blood lipid levels of the mice were measured during the experimental period. The liver and pancreas tissues were collected for pathological, quantitative real-time polymerase chain reaction, and Western blotting analyses. RESULTS: Compared with the DM group, the Qihu groups exhibited decreased bodyweight gain. The blood glucose levels in the Qihu-L, Qihu-M, and Qihu-H were 31.46%, 43.73%, and 51.83%, respectively, lower than those in the DM group. The triglyceride levels were significantly downregulated and the swelling and steatosis of the hepatocytes were significantly lower in the Qihu-M and Qihu-H groups than in the DM group. Qihu downregulated the expression of IL-1ß, IL-6, and TXNIP and upregulated the AMP-activated protein kinase (AMPK) signaling pathway in the pancreas and liver tissues of db/db mice. CONCLUSION: The anti-diabetic effects of Qihu are mediated through the activation of the AMPK/Txnip signaling and the downregulation of the secretion of inflammatory factors in db/db mice.

CCT020312 Inhibits Triple-Negative Breast Cancer Through PERK Pathway-Mediated G1 Phase Cell Cycle Arrest and Apoptosis.

Triple-negative breast cancer (TNBC) has a poor prognosis due to the lack of specific therapeutic targets. CCT020312, a selective eukaryotic translation initiation factor 2 alpha (eIF2α)/protein kinase RNA-like endoplasmic reticulum kinase (PERK) activator, may have a potent anti-tumor effect. In the present study, we examined the effects of CCT020312 on TNBC and explored the underlying mechanism. We found that CCT020312 inhibited the viability of TNBC cell lines, MDA-MB-453 and CAL-148, by inducing apoptosis and G1 phase cell cycle arrest. CCT020312 decreased the protein levels of cyclin-dependent kinase 4 (CDK4), CDK6, cyclin D1, and B-cell lymphoma 2 (Bcl-2) and increased the levels of Bcl-2-associated X protein (Bax) and cleaved poly (ADP-ribose) polymerase (PARP) compared with those in the control. CCT020312 activated PERK/eIF2α/activating transcription factor 4 (ATF4)/CCAAT-enhancer binding protein (C/EBP) homologous protein transcription factor (CHOP) signaling and inhibited protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling. Furthermore, CCT020312 inhibited tumor growth in an MDA-MB-453 orthotopic xenograft mouse model by activating the PERK/eIF2α/ATF4/CHOP pathway and inhibiting the AKT/mTOR pathway. Thus, our study shows that CCT020312 may be a potential drug candidate for TNBC treatment.

The Anti-Breast Cancer Effect and Mechanism of Glimepiride-Metformin Adduct.

BACKGROUND: Compound adduct is a eutectic crystal formed by non-covalent bonds of two compounds or multiple compounds with water. Emerging evidence suggests that adduct could be different from the simple physical mixture of the individual compounds and has some new features. Recent studies reported that both glimepiride (Gli) and metformin (Met) may possess an anti-breast cancer effect besides anti-diabetic effect. In the current study, we synthesized glimepiride-metformin adduct (GMA) and examined its anti-breast cancer effect in vitro and in vivo to explore its potential in treatment of breast cancer in diabetic patients. METHODS: GMA was synthesized from Gli, Met and water at a molar molecular mass of 1:1:1 and identified by infrared spectroscopy. MTT assay, colony formation assay and wound healing assay were performed to examine the effects of GMA on cell viability and migration of human breast cancer cell lines CAL-148, MDA-MB-453, MDA-MB-231and MCF-7. The effect of GMA on cell cycle and apoptosis was examined by flow cytometry. The orthotopic implantation model was established to observe the inhibitory effect of GMA on tumor growth. The expression of Ki67 was detected by immunohistochemistry. RT-qPCR and Western blotting were performed to investigate mechanisms for the function of GMA. RESULTS: Both MTT and colony formation assays showed that GMA inhibited breast cancer cell viability, and the effect was greater than Gli alone, Met alone and the combination. In vivo study showed that GMA had an inhibitory effect on tumor growth of CAL-148 xenografts. Flow cytometry analysis indicated that GMA induced G1/S phase cell cycle arrest and apoptosis in breast cancer cells. RT-qPCR and Western blotting analyses showed that GMA activated AMPK, and up-regulated expression of p53 and p21, and down-regulated expression of cyclin D1 and CDK4. CONCLUSION: GMA suppresses cell viability of breast cancer cells, and its effect is greater than Gli and Met alone or combination at the same concentration. GMA inhibits breast cancer cell growth in vivo. The antitumor effect of GMA may be related to the activation of AMPK resulting in up-regulation of p53 and p21 and down-regulation of cyclin D1 and CDK4.