FXR activation remodels hepatic and intestinal transcriptional landscapes in metabolic dysfunction-associated steatohepatitis.

The escalating obesity epidemic and aging population have propelled metabolic dysfunction-associated steatohepatitis (MASH) to the forefront of public health concerns. The activation of FXR shows promise to combat MASH and its detrimental consequences. However, the specific alterations within the MASH-related transcriptional network remain elusive, hindering the development of more precise and effective therapeutic strategies. Through a comprehensive analysis of liver RNA-seq data from human and mouse MASH samples, we identified central perturbations within the MASH-associated transcriptional network, including disrupted cellular metabolism and mitochondrial function, decreased tissue repair capability, and increased inflammation and fibrosis. By employing integrated transcriptome profiling of diverse FXR agonists-treated mice, FXR liver-specific knockout mice, and open-source human datasets, we determined that hepatic FXR activation effectively ameliorated MASH by reversing the dysregulated metabolic and inflammatory networks implicated in MASH pathogenesis. This mitigation encompassed resolving fibrosis and reducing immune infiltration. By understanding the core regulatory network of FXR, which is directly correlated with disease severity and treatment response, we identified approximately one-third of the patients who could potentially benefit from FXR agonist therapy. A similar analysis involving intestinal RNA-seq data from FXR agonists-treated mice and FXR intestine-specific knockout mice revealed that intestinal FXR activation attenuates intestinal inflammation, and has promise in attenuating hepatic inflammation and fibrosis. Collectively, our study uncovers the intricate pathophysiological features of MASH at a transcriptional level and highlights the complex interplay between FXR activation and both MASH progression and regression. These findings contribute to precise drug development, utilization, and efficacy evaluation, ultimately aiming to improve patient outcomes.

DGAT1 inhibitors protect pancreatic ß-cells from palmitic acid-induced apoptosis.

Previous studies demonstrated that prolonged exposure to elevated levels of free fatty acids (FFA), especially saturated fatty acids, could lead to pancreatic ß-cell apoptosis, which plays an important role in the progression of type 2 diabetes (T2D). Diacylglycerol acyltransferase 1 (DGAT1), an enzyme that catalyzes the final step of triglyceride (TG) synthesis, has been reported as a novel target for the treatment of multiple metabolic diseases. In this study we evaluated the potential beneficial effects of DGAT1 inhibitors on pancreatic ß-cells, and further verified their antidiabetic effects in db/db mice. We showed that DGAT1 inhibitors (4a and LCQ908) at the concentration of 1 µM significantly ameliorated palmitic acid (PA)-induced apoptosis in MIN6 pancreatic ß-cells and primary cultured mouse islets; oral administration of a DGAT1 inhibitor (4a) (100 mg/kg) for 4 weeks significantly reduced the apoptosis of pancreatic islets in db/db mice. Meanwhile, 4a administration significantly decreased fasting blood glucose and TG levels, and improved glucose tolerance and insulin tolerance in db/db mice. Furthermore, we revealed that pretreatment with 4a (1 µM) significantly alleviated PA-induced intracellular lipid accumulation, endoplasmic reticulum (ER) stress, and proinflammatory responses in MIN6 cells, which might contribute to the protective effects of DGAT1 inhibitors on pancreatic ß-cells. These findings provided a better understanding of the antidiabetic effects of DGAT1 inhibitors.

The epigenetic regulator SIRT6 protects the liver from alcohol-induced tissue injury by reducing oxidative stress in mice.

BACKGROUND & AIMS: As a nicotinamide adenine dinucleotide-dependent deacetylase and a key epigenetic regulator, sirtuin 6 (SIRT6) has been implicated in the regulation of metabolism, DNA repair, and inflammation. However, the role of SIRT6 in alcohol-related liver disease (ALD) remains unclear. The aim of this study was to investigate the function and mechanism of SIRT6 in ALD pathogenesis. METHODS: We developed and characterized Sirt6 knockout (KO) and transgenic mouse models that were treated with either control or ethanol diet. Hepatic steatosis, inflammation, and oxidative stress were analyzed using biochemical and histological methods. Gene regulation was analyzed by luciferase reporter and chromatin immunoprecipitation assays. RESULTS: The Sirt6 KO mice developed severe liver injury characterized by a remarkable increase of oxidative stress and inflammation, whereas the Sirt6 transgenic mice were protected from ALD via normalization of hepatic lipids, inflammatory response, and oxidative stress. Our molecular analysis has identified a number of novel Sirt6-regulated genes that are involved in antioxidative stress, including metallothionein 1 and 2 (Mt1 and Mt2). Mt1/2 genes were downregulated in the livers of Sirt6 KO mice and patients with alcoholic hepatitis. Overexpression of Mt1 in the liver of Sirt6 KO mice improved ALD by reducing hepatic oxidative stress and inflammation. We also identified a critical link between SIRT6 and metal regulatory transcription factor 1 (Mtf1) via a physical interaction and functional coactivation. Mt1/2 promoter reporter assays showed a strong synergistic effect of SIRT6 on the transcriptional activity of Mtf1. CONCLUSIONS: Our data suggest that SIRT6 plays a critical protective role against ALD and it may serve as a potential therapeutic target for ALD. LAY SUMMARY: The liver, the primary organ for ethanol metabolism, can be damaged by the byproducts of ethanol metabolism, including reactive oxygen species. In this study, we have identified a key epigenetic regulator SIRT6 that plays a critical role in protecting the liver from oxidative stress-induced liver injury. Thus, our data suggest that SIRT6 may be a potential therapeutic target for alcohol-related liver disease.

Small molecule IVQ, as a prodrug of gluconeogenesis inhibitor QVO, efficiently ameliorates glucose homeostasis in type 2 diabetic mice.

Gluconeogenesis is a major source of hyperglycemia in patients with type 2 diabetes mellitus (T2DM), thus targeting gluconeogenesis to suppress glucose production is a promising strategy for anti-T2DM drug discovery. In our preliminary in vitro studies, we found that a small-molecule (E)-3-(2-(quinoline-4-yl)vinyl)-1H-indol-6-ol (QVO) inhibited the hepatic glucose production (HGP) in primary hepatocytes. We further revealed that QVO suppressed hepatic gluconeogenesis involving calmodulin-dependent protein kinase kinase ß- and liver kinase B1-adenosine monophosphate-activated protein kinase (AMPK) pathways as well as AMPK-independent mitochondrial function-related signaling pathway. To evaluate QVO's anti-T2DM activity in vivo, which was impeded by the complicated synthesis route of QVO with a low yield, we designed and synthesized 4-[2-(1H-indol-3-yl)vinyl]quinoline (IVQ) as a prodrug with easier synthesis route and higher yield. IVQ did not inhibit the HGP in primary hepatocytes in vitro. Pharmacokinetic studies demonstrated that IVQ was quickly converted to QVO in mice and rats following administration. In both db/db and ob/ob mice, oral administration of IVQ hydrochloride (IVQ-HCl) (23 and 46 mg/kg every day, for 5 weeks) ameliorated hyperglycemia, and suppressed hepatic gluconeogenesis and activated AMPK signaling pathway in the liver tissues. Furthermore, IVQ caused neither cardiovascular system dysfunction nor genotoxicity. The good druggability of IVQ has highlighted its potential in the treatment of T2DM and the prodrug design for anti-T2DM drug development.

Effect of Bulk MoS2 on the Metabolic Profile of Yeast.

MoS2, a kind of two-dimensional material with unique performances, has been widely used in many fields. However, an in-depth understanding of its toxicity is still needed, let alone its effects on the environmental microorganism. Herein, we used different methods, including metabolomics technology, to investigate the influence of bulk MoS2 (BMS) on yeast cells. The results indicated that high concentrations (1 mg/L and more) of BMS could destroy cell membrane and induce ROS accumulation. When exposed to a low concentration of BMS (0.1 mg/L), the intracellular concentrations of many metabolites (e.g., fumaric acid, lysine) increased. However, most of their concentrations descended significantly as the yeast cells were treated with BMS of high concentrations (1 mg/L and more). Metabolomics analysis further revealed that exposure to high concentrations of BMS could significantly affect some metabolic pathways such as amino acid and citrate cycle related metabolism. These findings will be beneficial for MoS2 toxicity assessment and further applications.

Discovery of a low-systemic-exposure DGAT-1 inhibitor with a picolinoylpyrrolidine-2-carboxylic acid moiety.

A series of diacylglycerol O-acyltransferase 1 (DGAT-1) inhibitors with a picolinoylpyrrolidine-2-carboxylic acid moiety were designed and synthesized. Of these compounds, compound 22 exhibited excellent DGAT-1-inhibitory activity (hDGAT-1 enzyme assay, 50% inhibitory concentration [IC50]=3.5±0.9nM) and effectively reduced the intracellular triglyceride contents in 3T3-L1, HepG2 and Caco-2 cells. A preliminary study of the plasma and tissue distributions of compound 22 in mice revealed low plasma exposure and high concentrations in different segments of the intestine and liver, which may facilitate targeting DGAT-1. Furthermore, in an acute lipid challenge test, compound 22 showed a dose-dependent inhibitory effect on high-serum triglycerides in C57/KSJ mice induced by olive oil (1, 3, and 10mg/kg, i.g.).

Sirtuin 6 regulates glucose-stimulated insulin secretion in mouse pancreatic beta cells.

AIMS/HYPOTHESIS: Sirtuin 6 (SIRT6) has been implicated in ageing, DNA repair and metabolism; however, its function in pancreatic beta cells is unclear. The aim of this study is to elucidate the role of SIRT6 in pancreatic beta cells. METHODS: To investigate the function of SIRT6 in pancreatic beta cells, we performed Sirt6 gene knockdown in MIN6 cells and generated pancreatic- and beta cell-specific Sirt6 knockout mice. Islet morphology and glucose-stimulated insulin secretion (GSIS) were analysed. Glycolysis and oxygen consumption rates in SIRT6-deficient beta cells were measured. Cytosolic calcium was monitored using the Fura-2-AM fluorescent probe (Invitrogen, Grand Island, NY, USA). Mitochondria were analysed by immunoblots and electron microscopy. RESULTS: Sirt6 knockdown in MIN6 beta cells led to a significant decrease in GSIS. Pancreatic beta cell Sirt6 knockout mice showed a ~50% decrease in GSIS. The knockout mouse islets had lower ATP levels compared with the wild-type controls. Mitochondrial oxygen consumption rates were significantly decreased in the SIRT6-deficient beta cells. Cytosolic calcium dynamics in response to glucose or potassium chloride were attenuated in the Sirt6 knockout islets. Numbers of damaged mitochondria were increased and mitochondrial complex levels were decreased in the SIRT6-deficient islets. CONCLUSIONS/INTERPRETATION: These data suggest that SIRT6 is important for GSIS from pancreatic beta cells and activation of SIRT6 may be useful to improve insulin secretion in diabetes.

Inhibitory Effects of (2'R)-2',3'-dihydro-2'-(1-hydroxy-1-methylethyl)-2,6'-bibenzofuran-6,4'-diol on Mushroom Tyrosinase and Melanogenesis in B16-F10 Melanoma Cells.

(2'R)-2',3'-Dihydro-2'-(1-hydroxy-1-methylethyl)-2,6'-bibenzofuran-6,4'-diol (DHMB) is a natural compound extracted from Morus notabilis. It was found that DHMB acts as a competitive inhibitor against mushroom tyrosinase with a Ki value of 14.77 µM. Docking results further indicated that it could form strong interactions with one copper ion with a distance of 2.7 Å, suggesting the mechanism of inhibition might be due to chelating copper ions in the active site. Furthermore, melanin production in B16-F10 murine melanoma cells was significantly inhibited by DHMB in a concentration-dependent manner without cytotoxicity. The results of western blotting also showed that DHMB decreased 3-isobuty-1-methxlzanthine-induced mature tyrosinase expression. Taken together, these findings indicated that DHMB may be a new promising pigmentation-altering agent for agriculture, cosmetic, and therapeutic applications.

Aphadilactones A-D, four diterpenoid dimers with DGAT inhibitory and antimalarial activities from a Meliaceae plant.

Aphadilactones A-D (1-4), four diastereoisomers possessing an unprecedented carbon skeleton, were isolated from the Meliaceae plant Aphanamixis grandifolia. Their challenging structures and absolute configurations were determined by a combination of spectroscopic data, chemical degradation, fragment synthesis, experimental CD spectra, and ECD calculations. Aphadilactone C (3) with the 5S,11S,5'S,11'S configuration showed potent and selective inhibition against the diacylglycerol O-acyltransferase-1 (DGAT-1) enzyme (IC50 = 0.46 ± 0.09 µM, selectivity index > 217) and is the strongest natural DGAT-1 inhibitor discovered to date. In addition, compounds 1-4 showed significant antimalarial activities with IC50 values of 190 ± 60, 1350 ± 150, 170 ± 10, and 120 ± 50 nM, respectively.

Latanoprost effectively ameliorates glucose and lipid disorders in db/db and ob/ob mice.

AIMS/HYPOTHESIS: Improvement of glucose and lipid metabolic dysfunctions is a potent therapeutic strategy against type 2 diabetes mellitus, and identifying new functions for existing drugs may help accelerate the speed of new drug development. Here, we report that latanoprost, a clinical drug for treating primary open-angle glaucoma and intraocular hypertension, effectively ameliorated glucose and lipid disorders in two mouse models of type 2 diabetes. In addition, the glucose-lowering mechanisms of latanoprost were intensively investigated. METHODS: A binding-affinity assay and enzymatic tests were used to determine the targets of latanoprost. Cell-based assays on 3T3-L1 adipocytes and C2C12 myotubes and animal model-based assays with db/db and ob/ob mice were further performed to clarify the mechanisms underlying latanoprost-regulated glucose and lipid metabolism. RESULTS: Latanoprost functioned as both an indirect activator of AMP-activated protein kinase and a selective retinoid X receptor α (RXRα) antagonist able to selectively antagonise the transcription of a RXRα/peroxisome proliferator-activated receptor γ heterodimer. It promoted glucose uptake, inhibited pre-adipocyte differentiation and regulated the main genes responsible for glucose and lipid metabolism, including Fas, Scd1, Perilipin (also known as Plin1), Lpl and Pdk4. Chronic administration of latanoprost in mice potently decreased the levels of fasting blood glucose, HbA1c, fructosamine (FMN), NEFA and total cholesterol, and effectively improved glucose tolerance and glucose/lipid metabolism-related genes in vivo. CONCLUSIONS/INTERPRETATION: Our studies demonstrate that the existing eye drug latanoprost is both an indirect activator of AMP-activated protein kinase and a selective RXRα antagonist. Latanoprost effectively ameliorated glucose and lipid disorders in diabetic mice, which strongly highlights the potential of latanoprost in the treatment of type 2 diabetes mellitus.

Dodoviscin a inhibits melanogenesis in mouse b16-f10 melanoma cells.

Nowadays, abnormal hyperpigmentation in human skin such as melasma, freckles, and chloasma has become a serious esthetic problem. Cutaneous depigmenting agents could be used to treat these hyperpigmentation-associated dieseases. Dodoviscin A is a natural product isolated from the aerial parts of Dodonaea viscosa. In the present study, we evaluated the effect of dodoviscin A on melanin production in B16-F10 melanoma cells for the first time. We found that dodoviscin A inhibited melanin biosynthesis induced by 3-isobutyl-1-methylxanthine and PD98059 significantly, and there was no obvious effect on the viability of dodoviscin A-treated B16-F10 cells. Meanwhile, dodoviscin A could suppress the activity of mushroom tyrosinase in the cell-free assay system and also decrease 3-isobutyl-1-methylxanthine-induced tyrosinase activity and expression of mature tyrosinase protein in B16-F10 cells. Western blotting analysis showed that dodoviscin A inhibited 3-isobutyl-1-methylxanthine and forskolin-induced phosphorylation of the cAMP response element binding protein in B16-F10 cells. These results indicate that dodoviscin A may be a new promising pigmentation-altering agent for cosmetic and therapeutic applications.

Combining pharmacophore, docking and substructure search approaches to identify and optimize novel B-RafV600E inhibitors.

In this study for searching novel B-Raf(V600E) inhibitors, pharmacophore-based virtual screening identified 1 as a hit bearing 5-benzylidene-2-thioxodihydropyrimidine-4,6(1H,5H)-dione. Based on 1, scaffold hopping inspired by molecular docking discovered 5-(furan-2-ylmethylene)-2-thioxodihydropyrimidine-4,6(1H,5H)-dione as a new and better scaffold. Substructure search with the new scaffold identified 28 active compounds, among which 12 compounds (42.9%) showed IC(50) less than 1 µM. Especially, compound 3o, which is 10-fold more potent than the hit 1, is a potent inhibitor comparable to that of the marketed drug vemurafenib.

Effect of Polyaniline and Graphene Oxide Modified Carbon Felt on Adsorption and Immobilization of Acidithiobacillus ferrooxidans.

Biological desulfurization plays an increasingly important role in desulfurization industry. A strain of Acidithiobacillus ferrooxidans ZJ-2 with high Fe2+ oxidizing efficiency was in this study isolated and screened to remove hydrogen sulfide from biogas. To further improve its oxidation efficiency, A. ferrooxidans ZJ-2 was immobilized using carbon felt (CF), modified with graphene oxide (GO) and polyaniline (PANI), as immobilized carrier. The effects of immobilization on strain's Fe2+ oxidation efficiency and impact of PANI and GO on CF were also investigated. Raman spectra and atomic force microscopy showed that CF was successfully modified using GO and PANI. Cyclic voltammetry and electrochemical impedance spectroscopy measurements revealed that the electrochemical properties of modified CF were improved, presenting the following trend in conductivity: CF< GO-modified CF (GO-CF) < PANI-modified CF (PANI-CF) < PANI/GO-modified CF (PANI/GO-CF). The resistance of modified CF was lower than that of unmodified CF, and exhibited the following trend: CF > GO-CF > PANI-CF > GO/PANI-CF. While PANI-CF inhibited growth of free and immobilized A. ferrooxidans ZJ-2, GO-CF was conducive to microbial growth and increased cell density and oxidation ability of A. ferrooxidans ZJ-2. Thus, the present study developed an immobilized bacterial carrier that had better conductivity and lower resistance and was efficient in immobilizing A. ferrooxidans and could be used for biogas desulfurization in biological and biochemical combined reactors.

DMT efficiently inhibits hepatic gluconeogenesis by regulating the Gαq signaling pathway.

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease with complicated pathogenesis and targeting gluconeogenesis inhibition is a promising strategy for anti-diabetic drug discovery. G protein-coupled receptors (GPCRs) are classified as distinct families by heterotrimeric G proteins, primarily including Gαs, Gαi and Gαq. Gαs-coupled GPCRs function potently in the regulation of hepatic gluconeogenesis by activating cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) pathway and Gαi-coupled GPCRs exhibit inhibitory effect on adenylyl cyclase and reduce intracellular cAMP level. However, little is known about the regulation of Gαq-coupled GPCRs in hepatic gluconeogenesis. Here, small-molecule 2-(2,4-dimethoxy-3-methylphenyl)-7-(thiophen-2-yl)-9-(trifluoromethyl)-2,3-dihydropyrido[3',2':4,5]thieno[3,2-d]pyrimidin-4(1H)-one (DMT) was determined to suppress hepatic glucose production and reduce mRNA levels of gluconeogenic genes. Treatment of DMT in db/db mice decreased fasting blood glucose and hemoglobin A1C (HbA1c) levels, while improved glucose tolerance and pyruvate tolerance. Mechanism study demonstrated that DMT-inhibited gluconeogenesis by regulating the Gαq/phospholipase C (PLC)/inositol-1,4,5-triphosphate receptor (IP3R)-mediated calcium (Ca2+)/calmodulin (CaM)/phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase B (AKT)/forkhead box protein O1 (FOXO1) signaling pathway. To our knowledge, DMT might be the first reported small molecule able to suppress hepatic gluconeogenesis by regulating Gαq signaling, and our current work has also highlighted the potential of DMT in the treatment of T2DM.

An intrinsic agonist mechanism for activation of glucagon-like peptide-1 receptor by its extracellular domain.

The glucagon-like peptide-1 receptor is a class B G protein coupled receptor (GPCR) that plays key roles in glucose metabolism and is a major therapeutic target for diabetes. The classic two-domain model for class B GPCR activation proposes that the apo-state receptor is auto-inhibited by its extracellular domain, which physically interacts with the transmembrane domain. The binding of the C-terminus of the peptide hormone to the extracellular domain allows the N-terminus of the hormone to insert into the transmembrane domain to induce receptor activation. In contrast to this model, here we demonstrate that glucagon-like peptide-1 receptor can be activated by N-terminally truncated glucagon-like peptide-1 or exendin-4 when fused to the receptor, raising the question regarding the role of N-terminal residues of peptide hormone in glucagon-like peptide-1 receptor activation. Mutations of cysteine 347 to lysine or arginine in intracellular loop 3 transform the receptor into a G protein-biased receptor and allow it to be activated by a nonspecific five-residue linker that is completely devoid of exendin-4 or glucagon-like peptide-1 sequence but still requires the presence of an intact extracellular domain. Moreover, the extracellular domain can activate the receptor in trans in the presence of an intact peptide hormone, and specific mutations in three extracellular loops abolished this extracellular domain trans-activation. Together, our data reveal a dominant role of the extracellular domain in glucagon-like peptide-1 receptor activation and support an intrinsic agonist model of the extracellular domain, in which peptide binding switches the receptor from the auto-inhibited state to the auto-activated state by releasing the intrinsic agonist activity of the extracellular domain.

BBT improves glucose homeostasis by ameliorating ß-cell dysfunction in type 2 diabetic mice.

Impaired glucose-stimulated insulin secretion (GSIS) and increasing ß-cell death are two typical dysfunctions of pancreatic ß-cells in individuals that are destined to develop type 2 diabetes, and improvement of ß-cell function through GSIS enhancement and/or inhibition of ß-cell death is a promising strategy for anti-diabetic therapy. In this study, we discovered that the small molecule, N-(2-benzoylphenyl)-5-bromo-2-thiophenecarboxamide (BBT), was effective in both potentiating GSIS and protecting ß-cells from cytokine- or streptozotocin (STZ)-induced cell death. Results of further studies revealed that cAMP/PKA and long-lasting (L-type) voltage-dependent Ca(2) (+) channel/CaMK2 pathways were involved in the action of BBT against GSIS, and that the cAMP/PKA pathway was essential for the protective action of BBT on ß-cells. An assay using the model of type 2 diabetic mice induced by high-fat diet combined with STZ (STZ/HFD) demonstrated that BBT administration efficiently restored ß-cell functions as indicated by the increased plasma insulin level and decrease in the ß-cell loss induced by STZ/HFD. Moreover, the results indicated that BBT treatment decreased fasting blood glucose and HbA1c and improved oral glucose tolerance further highlighting the potential of BBT in anti-hyperglycemia research.

Novel approaches to drug discovery for the treatment of type 2 diabetes.

INTRODUCTION: Type 2 diabetes mellitus (T2DM) is a chronic, complex and multifactorial metabolic disorder, which has become a serious global health problem. The side effects of known drugs and the deficiency of long-term safety data, in addition to the already determined adverse effects for the current preclinical drugs against T2DM, have largely called upon the urgent exploration of novel therapeutic and preventative strategies against this disease. AREAS COVERED: The authors highlight the potential approaches for anti-T2DM drug discovery by focusing on: the restoration of pancreatic ß-cell mass, the promotion of insulin secretion, the regulation of oxidative stress and endoplasmic reticulum (ER) stress and the modulation of autophagy. EXPERT OPINION: T2DM is based on the gradual development of insulin resistance and ß-cell dysfunction. Thus, the restoration of ß-cell function is considered as one of the promising therapeutic strategies against T2DM. The stress factors, such as oxidative stress, ER stress and autophagy, play potent roles in the regulation of ß-cell apoptosis, insulin secretion and sensitivity in the development of T2DM involving complicated cross-talks. Based on multiplex stress-involved regulatory networks, more and more novel potential targets have been discovered and the multi-targeted drug leads are expected to help develop more effective clinical agents for the treatment of T2DM.

Discovery of N-substituted 3-arylisoquinolone derivatives as antitumor agents originating from O-substituted 3-arylisoquinolines via [2,3] or [3,3] rearrangement.

The present study discovers multiple N-substituted 3-arylisoquinolone derivatives as antitumor agents originating from O-substituted 3-arylisoquinolines via [2,3] or [3,3] rearrangement. The current [2,3] rearrangement of epoxy or acetal O-substituents converting to diol or alcohol N-substituents can be promoted by silica gel or by diluted hydrochloric acid, which is distinct from previously reported [2,3] rearrangements. Some of the derivatives displayed comparable or even stronger cytotoxicity than sorafenib and vemurafenib on HCT116 colon carcinoma and A375 melanoma cell lines. Therefore, the rearrangement via intramolecular carbon-oxygen bond cleavage and carbon-nitrogen bond formation should be a useful approach for developing novel anticancer drugs derived from isoquinolones.

Overman rearrangement and Pomeranz-Fritsch reaction for the synthesis of benzoazepinoisoquinolones to discover novel antitumor agents.

The B-ring of Benzoazepinoisoquinolones 1a-b was successfully constructed by Pomeranz-Fritsch reaction. The key intermediates 5a-b could be transformed from 9a-b via Overman rearrangement. The bioassay showed that 11 compounds are more active than sorafenib (IC50 = 7.56 µM) against A375 melanoma cell line, among which 1a, 5a, 8a and 10c with IC50 values of 0.59, 0.20, 0.17 and 0.11 µM, respectively, showed potent cytotoxicity close to or even stronger than the anti-melanoma drug vemurafenib (IC50 = 0.18 µM). In addition, 5a, 8a and 10c are more active than both vemurafenib and sorafenib on HCT116 colon cell line (IC50 values: 0.86, 0.65, 0.42, >30 and 5.65 µM for 5a, 8a, 10c, vemurafenib and sorafenib). Therefore, these compounds are promising candidates for further drug development.

Blockage of progesterone receptor effectively protects pancreatic islet beta cell viability.

The progesterone receptor (PR), a member of nuclear receptor superfamily, is closely associated with gestational, type 1 and type 2 diabetes. However, the underlying mechanisms remain obscure. Here we found that PR activation increased the pro-inflammatory cytokines (PIC)-induced injury in Min6 cells, and PR blockage with siRNA interference protected the cells from damage. Moreover, the new discovered PR antagonist SC51089 effectively improved cell survival by reducing the PIC-stimulated cell apoptosis in Min6 cells. Immunoblotting assays indicated that either PR agonist progesterone (P4) or PR-B over-expression promoted the PIC-induced reinforces of extracellular-signal-regulated kinase 1/2 phosphorylation (p-Erk) and protein 53 (p53), and the attenuations of protein kinase B phosphorylation (p-AKT) and tumor necrosis factor receptor-associated factor 2 (TRAF2). SC51089 could reverse all the P4- or PR-B over-expression induced effects. In addition, PR siRNA inference based assay further supported that SC51089 protected pancreatic islet beta cells from the PR activation or PIC-induced injury by targeting PR and this protective action was mediated by AKT signaling pathway. To our knowledge, this current work might be the first report on the regulation of PR in pancreatic islet beta cell survival. It is expected that SC51089, as a non-steroid PR antagonist, might also find its potential in anti-diabetic research.