Pharmacokinetics and Tissue Distribution of a Novel Bis-Chelated Gold(I) Diphosphine Compound, Bis(2,3-bis(tert-butylmethylphosphino)Quinoxaline)Aurate(I), in Rats.

GC20, a novel soluble bis-chelated gold(I)-diphosphine compound, has been reported as a promising anticancer candidate. Assessing the pharmacokinetic properties of GC20 is critical for its medicinal evaluation. First, a sensitive and specific liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and well validated to determine GC20 in rat plasma and rat tissue homogenate after one step protein precipitation. Chromatographic separation was achieved on an Angilent ZORBAX-C18 column (3.5 µm, 2.1 × 50 mm) with gradient elution and mass spectrometry was performed on a triple quadrupole in positive ion mode using an electrospray ionization source. This method was then applied to investigate the pharmacokinetics and tissue distribution of GC20 in rats after intravenous administration. The results showed that the plasma exposure of GC20 in vivo increased with increasing doses after a single dose. However, after multiple doses, a significant accumulation and a saturation at elimination were observed for GC20 in rats. Moreover, after intravenous administration, GC20 was widely distributed in various tissues, with the highest levels in the lung, spleen, liver, and pancreas, followed by the kidney and heart, while the lowest level was found in the brain. This is the first report on the pharmacokinetic properties of GC20.

ERK inhibitor JSI287 alleviates imiquimod-induced mice skin lesions by ERK/IL-17 signaling pathway.

Many studies confirmed that the over-activation of RAF-MEK-ERK signaling pathway plays a central role in human cancers. To avoid drug resistance during cancer treatment, many researchers focused on the study of the downstream therapeutic target of RAF-MEK-ERK signaling pathway. Therefore, ERK1/2 became a hot anticancer target. It has been shown that ERK phosphorylation could activate Th17 cells and therefore induce inflammatory diseases. Due to these results, inhibition of ERK, as a potential drug target, could provide a solution for autoimmune diseases, especially T cell mediated diseases. In this study, a small synthetic molecule JSI287 was found with the function of alleviating IMQ-induced mice skin lesions through ERK/IL-17 signaling pathway during the screening of small molecule databases targeting ERK. The results showed that JS1287 small molecule alleviated epidermal thickness, epidermis congestion, edema and inflammatory cell infiltration, decreased release of inflammatory cytokines of IL-6, IL-12 and IL-17A, and further regulated the mRNA expression of ATF1 and protein expression of ERK1/2 in IMQ-induced skin lesions. Our study suggested that ERK inhibitor JSI287 could be a promising candidate for psoriasis treatment.

Hypolipidemic effect of SIPI-7623, a derivative of an extract from oriental wormwood, through farnesoid X receptor antagonism.

Farnesoid X receptor (FXR) is a member of the nuclear receptor superfamily of ligand-activated transcription factors. As a metabolic regulator, FXR plays key roles in bile acid and cholesterol metabolism and lipid and glucose homeostasis. Therefore, FXR is a potential drug target for several metabolic syndromes, especially those related to lipidemia disorders. In the present study, we identified small molecule SIPI-7623, a derivative of an extract from Oriental wormwood (Artemisia capillaris), and found that it specifically upregulated the expression of cholesterol-7-alpha-hydroxylase (CYP7A1), downregulated the expression of sterol-regulatory element-binding protein 1c (SREBP-1c) in the liver, and inhibited the expression of ileal bile acid binding-protein (IBABP) in the ileum of rats. We found that inhibition of FXR by SIPI-7623 decreased the level of cholesterol and triglyceride. SIPI-7623 reduced the levels of cholesterol and triglyceride in in vitro HepG2 cell models, ameliorated diet-induced atherosclerosis, and decreased the serum lipid content on rats and rabbits model of atherosclerosis in vivo. Furthermore, SIPI-7623 decreased the extent of atherosclerotic lesions. Our resutls demonstrated that antagonism of the FXR pathway can be employed as a therapeutic strategy to treat metabolic diseases such as hyperlipidemia and atherosclerosis. In conclusion, SIPI-7623 could be a promising lead compound for development of drugs to treat hyperlipidemia and atherosclerosis.

Autophagy is a major mechanism for the dual effects of curcumin on renal cell carcinoma cells.

The aim of this study was to explore the effects of curcumin on renal cell carcinoma（RCC） through regulating autophagy. Cell viabilities were determined by MTT assay in RCC cells after treatment with curcumin at different concentrations for various durations. ATG7 silencing RCC cells were established to test the role of autophagy. The levels of key proteins on autophagy pathway were analyzed by Western blot. We found out that following 24 h curcumin treatment, the viability of RCC cells had an increase at 5 µM and no significant change at 20 µM but a decrease at 80 µM. These effects were affected by the inhibition of autophagy. When pre-incubated with inhibitors of the AMPK and ER stress pathways, the LC3II levels of RCC cells at 5 µM and 20 µM of curcumin were significantly decreased; however, when treated with the inhibitor of the oxidative stress pathway, the LC3II levels of RCC cells at 80 µM were significantly decreased. In conclusion, the present study indicated Curcumin protected cells from death at low concentration but promotes cell death at high concentration. Autophagy played a dual role in curcumin's effects on RCC. The AMPK and ER stress pathways might be involved at low concentrations of curcumin to protect cells, while the oxidative stress pathway might take part in toxicity at high curcumin concentration.

Oral JS-38, a metabolite from Xenorhabdus sp., has both anti-tumor activity and the ability to elevate peripheral neutrophils.

AIM: JS-38 (mitothiolore), a synthetic version of a metabolite isolated from Xenorhabdus sp., was evaluated for its anti-tumor and white blood cell (WBC) elevating activities. METHOD: These anti-proliferative activities were assessed in vitro using a panel of ten cell lines. The anti-tumor activities were tested in vivo using B16 allograft mouse models and xenograft models of A549 human lung carcinoma and QGY human hepatoma in nude mice. The anti-tumor interactions of JS-38 and cyclophosphamide (CTX) or 5-fluorouracil (5-Fu) were studied in a S180 sarcoma model in ICR mice. Specific stimulatory effects were determined on peripheral neutrophils in normal and CTX- and 5-Fu-induced neutropenic mice. RESULTS: The IC50 values ranged from 0.1 to 2.0 µmol·L(-1). JS-38 (1 µmol·L(-1)) caused an increase in A549 tumor cell apoptosis. Multi-daily gavage of JS-38 (15, 30, and 60 mg·kg(-1)·d(-1)) inhibited in vivo tumor progression without a significant effect on body weight. JS-38 additively enhanced the in vivo anti-tumor effects of CTX or 5-Fu. JS-38 increased peripheral neutrophil counts and neutrophil rates in normal BALB/c mice almost as effectively as granulocyte colony-stimulating factor (G-CSF). In mice with neutropenia induced by CTX or 5-Fu, JS-38 rapidly restored neutrophil counts. CONCLUSION: These results suggest that JS-38 has anti-tumor activity, and also has the ability to increase peripheral blood neutrophils.

Characterization of the anticancer effects of S115, a novel heteroaromatic thiosemicarbazone compound, in vitro and in vivo.

AIM: To investigate the anticancer effects of S115, a novel heteroaromatic thiosemicarbazone compound in vitro and in vivo. METHODS: The anti-proliferative action of S115 was analyzed in 12 human and mouse cancer cell lines using MTT assay. Autograft and xenograft cancer models were made by subcutaneous inoculation of cancer cells into mice or nude mice. The mice were orally treated with S115 (2, 8, 32 mg·kg(-1)·d(-1)) for 7 d, and the tumor size was measured every 3 d. Cell apoptosis and cell cycle distribution were examined using flow cytometry, gene expression profile analyses, Western blots and RT-PCR. RESULTS: The IC50 values of S115 against 12 human and mouse cancer cell lines ranged from 0.3 to 6.6 µmol/L. The tumor growth inhibition rate caused by oral administration of S115 (32 mg·kg(-1)·d(-1)) were 89.7%, 81.7%, 78.4% and 77.8%, respectively, in mouse model of B16 melanoma, mouse model of Colon26 colon cancer, nude mouse model of A549 lung cancer and nude mouse model of SK-OV-3 ovarian cancer. Furthermore, oral administration of S115 (7.5 mg·kg(-1)·d(-1)) synergistically enhanced the anticancer effects of cyclophosphamide, cisplatin, or 5-fluorouracil in mouse model of S180 sarcoma. Treatment of A549 human lung cancer cells with S115 (1.5 µmol/L) induced G0/G1 cell cycle arrest, and increased apoptosis. Furthermore, S115 downregulated the level of ubiquitin, and upregulated the level of Tob2 in A549 cells. CONCLUSION: S115 exerts anticancer effects against a variety of cancer cells in vitro and in grafted cancer models by inducing apoptosis, downregulating ubiquitin and upregulating Tob2.

A soluble bis-chelated gold(I) diphosphine compound with strong anticancer activity and low toxicity.

Gold-containing compounds have shown anticancer potential, but their clinical applications have been severely limited by poor stability and high toxicity in vivo. Here, we report a novel soluble bis-chelated gold(I)-diphosphine compound (GC20) with strong anticancer activity and low toxicity. GC20 shows strong antiproliferation potency against a broad spectrum of cancer cell lines including cisplatin-resistant cancer cells (IC50 ≈ 0.5 µM) and significantly reduces tumor growth in several tumor xenografts in mouse models at doses as low as 2 mg/kg. Studies of its mechanism revealed that GC20 specifically inhibits the enzymatic activity of thioredoxin reductase by binding to selenocysteine residue, without targeting other well-known selenol and thiol groups contained in biomolecules. Remarkably, in animal studies GC20 was shown to be well tolerated even at the high dose of 8 mg/kg. Our results strongly suggest that GC20 represents a promising candidate for the development of novel anticancer drugs.

Discovery of novel tubulin inhibitors via structure-based hierarchical virtual screening.

To discover novel tubulin inhibitors, we performed structure-based virtual screening against the colchicine binding pocket. In combination with a hierarchical docking and scoring procedure, the structural information of an additional subpocket in colchicine site was applied to filter out the undesired docking hits. This strategy automatically resulted in 63 candidates meeting the structural and energetic criteria from a screening library containing approximately 100,000 diverse druglike compounds. Among them, nine molecules were chosen for experimental validation, which all share the similar binding pose and contain an enriched scaffold bearing thiophene core. Encouragingly, five compounds are active in tubulin polymerization assay. The most potent inhibitor, 2-(2-fluorobenzamido)-3-carboxamide-4,5-dimethylthiophene, is structurally distinct to any known colchicine site binders and has higher ligand efficiency than colchicine. On the basis of its predicted binding pose, we systematically probed its binding characteristics by testing series of structural modifications. The obtained structure-activity relationship results are consistent with our binding model, and the inhibition activities of two analogues are improved by 2-fold. We expect that the novel structure discovered in the present study may serve as a starting point for developing tubulin inhibitors with improved efficacy and fewer side effects. We also expect that our hierarchical strategy may be generally applicable in structure-based virtual screening campaigns.

Metabolism and disposition of a novel antineoplastic JS-38 (Benzamide, N-[4-(2,4-dimethoxyphenyl)-4,5-dihydro-5-oxo-1,2-dithiolo[4,3-b]pyrrol-6-yl]-3,5-bis (trifluoromethyl)-(9Cl)) in rats.

The metabolism and catabolism of a novel antineoplastic (ID code JS-38),Benzamide, N-[4-(2,4-dimethoxyphenyl)-4,5-dihydro-5-oxo-1,2-dithiolo[4,3-b]pyrrol-6-yl]-3,5-bis (trifluoromethyl)-(9Cl), were investigated in Wistar rats (3 female, 3 male). LC/UV, LC/MS, LC/MS/MS, NMR and acid hydrolysis methods showed that the metabolic process of JS-38 consists of a series of acetylation and glucoronation that form a metabolic product with a unique pharmacologic property of accelerating bone-marrow cell formation, and also showed a novel metabolic pathway of being acetylated and glucuronated in series.

Synthesis and biological evaluation of 3-substituted-indolin-2-one derivatives containing chloropyrrole moieties.

Eighteen novel 3-substituted-indolin-2-ones containing chloropyrroles were synthesized and their biological activities were evaluated. The presence of a chlorine atom on the pyrrole ring was crucial to reduce cardiotoxicity. The presence of a 2-(ethyl-amino)ethylcarbamoyl group as a substituent at the C-4' position of the pyrrole enhanced the antitumor activities notably. IC50 values as low as 0.32, 0.67, 1.19 and 1.22 µM were achieved against non-small cell lung cancer (A549), oral epithelial (KB), melanoma (K111) and large cell lung cancer cell lines (NCI-H460), respectively.

[Effect of ZL-004 on raising leukocyte count].

This study is to investigate the effect of ZL-004 on normal mouse and mice with leukopenia induced by chemotherapeutic agents. 5-Fluorouracil were administered intraperitoneally to mice to develop leucopenia, and the mice were treated with ZL-004. The number of peripheral leukocytes and the percentage of granulocyte in total WBC were examined. The results are that ZL-004 markedly raise peripheral blood leukocytes in the normal mice and the mice model of leukopenia. So, ZL-004 could protect mice against 5-fluorouracil damage and raise peripheral blood leukocyte. Features of bone marrow smears is myeloproliferative hyperactivity in the mice, particularly the matured granulocytic series were observed. The mechanism of ZL-004 is to act on the mouse bone marrow causing proliferation and differentiation.

The pharmacokinetics of JS-38, a novel antineoplastic drug, in rats.

To evaluate the pre-clinical pharmacokinetics of JS-38(C22H1404N2S2F6, MW: 548), a study was conducted in Wistar rats (3 female, 2 male: 200-250 g about 6 or 7 months). The concentration-time curve of JS-38 in rats demonstrated the pharmacokinetic (PK) characteristics of a two-compartmental model. The area under the concentration-time curve from zero to infinity (AUC(0-infinity)) for the low, middle and high dosage (i.e., 20, 50 and 125 mg x kg(-1)) amounted to 46.850 +/- 19.946, 161.101 +/- 58.877 and 312.565 +/- 187.273 mg/L x h respectively; a positive correlation was demonstrated between the AUC(0-infinity). and the dosages in question (r = 0.99). The average time to reach maximum concentration (Tmax) was 3.( RSD: 20.4% and the half-life (t(1/2)) was 11.4 h( RSD: 8.8% P > 0.05. For the low, middle and high dosage, the maximum concentration (Cmax) was 4.882, 11.248, and 13.431 microg x mL(-1) respectively. After the administration of JS-38, except for the brain and spinal marrow, the drug distribution in the different body tissues varied, in particular in the liver, intestine and thyroid gland. A significant distribution of JS-38 was detected in cancerous tissues, and its concentrations demonstrated a tendency increase over time. There was a certain degree of distribution in the bone marrow. The urine samples showed that JS-38 nearly was practically not eliminated in its original form. The amount eliminated after 72h via the bile was only 1.03 +/- 0.1% of the administered dose. In the rat model, most of the JS-38 in its original form (53.58 +/- 22.28%) was excreted via the feces. When the intragastric administration of doses of 20, 50 and 125 mg x kg(-1) was compared with i.v. administered JS-38 (1 mg x kg(-1)), the absolute bioavailability amounted to 22.2 +/- 9.5%, 30.4 +/- 14.5% and 23.6 +/- 11.3% respectively. It was found that this compound is well absorbed in to the system and that it shows favorable PK properties. The outcome of this early pre-clinical study indicates that JS-38 is a promising drug candidate for further development.

Identification of novel inhibitors of the streptogramin group A acetyltransferase via virtual screening.

Virginiamycin acetyltransferase D (VatD) plays a vital rule in streptogramins resistance by chemically inactivating streptogramin A. Therefore, it is desirable to discover novel small molecular weight inhibitors of VatD via state-of-the-art virtual screening techniques. This "cocktail" strategy by combining VatD inhibitor with streptogramins may provide new therapeutic opportunity for resistant bacteria infections. Structure-based virtual screening method (molecular docking) was applied to rank and score a chemical database containing 300 000 commercially available compounds against the VatD substrate binding site. Twenty six out of the 200 top scored compounds from the docking calculation were selected and submitted to the VatD enzymatic inhibition assay. The plasmid pRSET B/vatD was constructed and transformed into E. coli (trxB) host cells for over-expression, and VatD enzyme was purified and validated by showing acetyltransferase activity to Virginiamycin M1. Three out of these 26 tested compounds showed enzymatic inhibition on VatD with IC50 168.6, 91.0 and 55.2 micromol x L(-1), separately. Other compounds could not be dissolved in the system and/or had little effect on the enzyme (IC50 > 200 micromol x L(-1)). To our knowledge, it is first time that small molecular weight organic compounds were identified as VatD inhibitors. It is expected that the VatD inhibitors identified at present study could serve as lead compounds for the further development of the novel therapeutic agents to overcome streptogramins resistance.