Small-molecule compounds targeting the STAT3 DNA-binding domain suppress survival of cisplatin-resistant human ovarian cancer cells by inducing apoptosis.

Constitutive activation of signal transducer and activator of transcription 3 (STAT3) plays important roles in oncogenic occurrence and transformation by regulating the expression of diverse downstream target genes important for tumor growth, metastasis, angiogenesis and immune evasion. Feasibility of targeting the DNA-binding domain (DBD) of STAT3 has been proven previously. With the aid of 3D shape- and electrostatic-based drug design, we identified a new STAT3 inhibitor, LC28, and its five analogs, based on the pharmacophore of a known STAT3 DBD inhibitor. Microscale thermophoresis assay shows that these compounds inhibits STAT3 binding to DNA with a Ki value of 0.74-8.87 µM. Furthermore, LC28 and its analogs suppress survival of cisplatin-resistant ovarian cancer cells by inhibiting STAT3 signaling and inducing apoptosis. Therefore, these compounds may serve as candidate compounds for further modification and development as anticancer therapeutics targeting the DBD of human STAT3 for treatment of cisplatin-resistant ovarian cancer.

Synthesis and bioactivity of 3,5-dimethylpyrazole derivatives as potential PDE4 inhibitors.

A series of 3,5-dimethylpyrazole derivatives containing 5-phenyl-2-furan moiety were designed and synthesized as phosphodiesterase type 4 (PDE4) inhibitors. Bioassay results showed that the title compounds exhibited considerable inhibitory activity against PDE4B and blockade of LPS-induced TNFα release. Among the designed compounds, compound If showed the best inhibitory activity against PDE4B with the IC50 value of 1.7 µM, which also showed good in vivo activity in animal models of asthma/COPD and sepsis induced by LPS. The primary structure-activity relationship (SAR) study and docking results suggested that introduction of the substituent groups to the phenyl ring at the para-position, especially methoxy group, was helpful to enhance inhibitory activity against PDE4B.

Synthesis and biological evaluation of 2,5-disubstituted furan derivatives as P-glycoprotein inhibitors for Doxorubicin resistance in MCF-7/ADR cell.

Multidrug resistance (MDR) is a tendency in which cells become resistant to structurally and mechanistically unrelated drugs, which is mediated by P-glycoprotein (P-gp). It is one of the noteworthy problems in cancer therapy. As one of the most important drugs in cancer therapy, doxorubicin has not good effectiveness if used independently. So targeting the P-gp protein is one of the key points to solve the MDR. Three series of furan derivatives containing tetrahydroquinoline or tetrahydroisoquinoline were designed and synthesized as P-gp inhibitors in this paper. Compound 5m containing 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline possessed good potency against P-gp (EC50 = 0.89 ±â€¯0.11 µM). The preliminary structure-activity relationship and docking studies demonstrated that compound 5m would be great promise as a lead compound for further study. Most worthy of mention is drug combination of doxorubicin and 5m displayed antiproliferative effect of about 97.8%. This study provides highlighted P-gp inhibitor for withstanding malignant tumor cell with multidrug resistance especially doxorubicin resistance setting the basis for further studies.

Synthesis and bioactivity of pyrazole and triazole derivatives as potential PDE4 inhibitors.

A series of pyrazole and triazole derivatives containing 5-phenyl-2-furan functionality were designed and synthesized as phosphodiesterase type 4 (PDE4) inhibitors. The bioassay results showed that title compounds exhibited considerable inhibitory activity against PDE4B and blockade of LPS-induced TNFα release. Meanwhile, the activity of compounds containing 1,2,4-triazole (series II) was higher than that of pyrazole-attached derivatives (series I). The primary structure-activity relationship study and docking results showed that the 1,2,4-triazole moiety of compound IIk played a key role to form integral hydrogen bonds and π-π stacking interaction with PDE4B protein while the rest part of the molecule extended into the catalytic domain to block the access of cAMP and formed the foundation for inhibition of PDE4. Compound IIk would be great promise as a hit compound for further study based on the preliminary structure-activity relationship and molecular modeling studies.

Sesquiterpene dimmer (DSF-27) inhibits the release of neuroinflammatory mediators from microglia by targeting spleen tyrosine kinase (Syk) and Janus kinase 2 (Jak2): Two major non-receptor tyrosine signaling proteins involved in inflammatory events.

Non-receptor protein tyrosine kinases (NRPTKs)-dependent inflammatory signal transduction cascades play key roles in immunoregulation. However, drug intervention through NRPTKs-involved immunoregulation mechanism in microglia (the major immune cells of the central nervous system) has not been widely investigated. A main aim of the present study is to elucidate the contribution of two major NRPTKs (Syk and Jak2) in neuroinflammation suppression by a bioactive sesquiterpene dimmer (DSF-27). We found that LPS-stimulated BV-2 cells activated Syk and further initiated Akt/NF-κB inflammatory pathway. This Syk-dependent Akt/NF-κB inflammatory pathway can be effectively ameliorated by DSF-27. Moreover, Jak2 was activated by LPS, which was followed by transcriptional factor Stat3 activation. The Jak2/Stat3 signal was suppressed by DSF-27 through inhibition of Jak2 and Stat3 phosphorylation, promotion of Jak/Stat3 inhibitory factors PIAS3 expression, and down-regulation of ERK and p38 MAPK phosphorylation. Furthermore, DSF-27 protected cortical and mesencephalic dopaminergic neurons against neuroinflammatory injury. Taken together, our findings indicate NRPTK signaling pathways including Syk/NF-κB and Jak2/Stat3 cascades are potential anti-neuroinflammatory targets in microglia, and may also set the basis for the use of sesquiterpene dimmer as a therapeutic approach for neuroinflammation via interruption of these pathways.

New limonoids from Coptidis Rhizoma-Euodiae Fructus couple.

A pair of inseparable new limonoids, named euodirutaecins A and B, were isolated from the Coptidis Rhizoma-Euodiae Fructus couple, together with two new single compounds evodirutaenin A and shihulimonin A1, and the known limonoids rutaevin, limonin, 12α-hydroxyrutaevin, and alkaloids rutaecarpine and evodiamine. Structures of these compounds were identified by spectral analyses and quantum chemical computational method, and the six limonoids were also evaluated for cytotoxicities against NCI-N87 and Caco-2 cell lines.

Anti-neuroinflammatory efficacy of the aldose reductase inhibitor FMHM via phospholipase C/protein kinase C-dependent NF-κB and MAPK pathways.

Aldose reductase (AR) has a key role in several inflammatory diseases: diabetes, cancer and cardiovascular diseases. Therefore, AR inhibition seems to be a useful strategy for anti-inflammation therapy. In the central nervous system (CNS), microglial over-activation is considered to be a central event in neuroinflammation. However, the effects of AR inhibition in CNS inflammation and its underlying mechanism of action remain unknown. In the present study, we found that FMHM (a naturally derived AR inhibitor from the roots of Polygala tricornis Gagnep.) showed potent anti-neuroinflammatory effects in vivo and in vitro by inhibiting microglial activation and expression of inflammatory mediators. Mechanistic studies showed that FMHM suppressed the activity of AR-dependent phospholipase C/protein kinase C signaling, which further resulted in downstream inactivation of the IκB kinase/IκB/nuclear factor-kappa B (NF-κB) inflammatory pathway. Therefore, AR inhibition-dependent NF-κB inactivation negatively regulated the transcription and expression of various inflammatory genes. AR inhibition by FMHM exerted neuroprotective effects in lipopolysaccharide-induced neuron-microglia co-cultures. These findings suggested that AR is a potential target for neuroinflammation inhibition and that FMHM could be an effective agent for treating or preventing neuroinflammatory diseases.

Sprengerinin C exerts anti-tumorigenic effects in hepatocellular carcinoma via inhibition of proliferation and angiogenesis and induction of apoptosis.

The multi-targeted therapy for liver cancer has been considered as a novel strategy to fight hepatocellular carcinoma. In this study, we first found that sprengerinin C, a naturally derived compound strongly suppressed tumor angiogenesis in human umbilical vein endothelial cells. A mechanism study revealed that sprengerinin C blocked vascular endothelial growth factor receptor 2-dependent phosphoinositide 3-kinase/Akt/mTOR/matrix metalloproteinase and p38 MAPK/matrix metalloproteinase pathways, two major pathways for tumor angiogenesis. Moreover, sprengerinin C inhibited vascular endothelial growth factor release, a vital event for early angiogenesis response, from hypoxic HepG-2/BEL7402 cells by suppressing hypoxia-inducible factor-1α transcriptional activity. Furthermore, sprengerinin C induced HepG-2/BEL7402 cell apoptosis by activating NADPH oxidase/reactive oxygen species-dependent caspase apoptosis pathway and suppressed HepG-2/BEL7402 cell growth through p53-mediated G2/M-phase arrest. Sprengerinin C also showed a significant anti-tumor effect in the nude mouse xenograft model of human hepatocellular carcinoma. These results provide new insights into development of potent candidate compounds for liver cancer through affecting multiple tumor progression steps of angiogenesis, apoptosis and proliferation.

Transferrin-cisplatin specifically deliver cisplatin to HepG2 cells in vitro and enhance cisplatin cytotoxicity.

Cisplatin is a major broad-spectrum chemotherapeutic agent, however, its dose-dependent side effects limit the administration of large doses. Presently, developing a drug targeted delivery system is suggested as one of the most promising approaches to minimize the side effects of cisplatin. Here, we found that each human serum transferrin (HTf) has the potential to bind with over 22 cisplatins, and the complex of apo-HTf-cisplatin can specifically deliver cisplatin to HepG2 cells (human hepatocellular liver carcinoma cell line) in vitro, and facilitate HepG2 cells to apoptosis. Moreover, proteomics methods revealed that the abundances of 23 proteins in HepG2 cells were remarkably altered in response to cisplatin/apo-HTf-cisplatin exposure, and Realtime-PCR revealed that a number of important genes related to chemotherapeutic cytotoxicity and chemotherapeutic resistance are differentially transcribed between the HepG2 cells of cisplatin exposed and HTf-cisplatin exposed. The pathway analysis of the differentially expressed proteins and gene transcriptions indicated that those regulated proteins and gene transcriptions are involved in apoptosis regulation, transcription, cell cycle control, protein biosynthesis, energy metabolism, signal transduction, protein binding and other functions. It indicated that the cisplatin toxicity in HepG2 cell is diverse, the transport process has an effect on the cisplatin cytotoxicity, and the mechanism of the apoptosis of HepG2 cells induced by apo-HTf-cisplatin is different from that of cisplatin.

Synthesis, physicochemical and biological properties of oligonucleotides incorporated with amino-isonucleosides.

Antisense oligonucleotides (ASONs) and siRNAs have been applied extensively for the regulation of cellular and viral gene expression, and RNAi is currently one of the most promising new approaches for anti-tumor and anti-viral therapy. In order to improve bioactivity properties and physicochemical properties of siRNA, we synthesized a novel class of ASONs II-VII incorporated with amino-isonucleoside (isoA 1 and isoA 2 ) for investigation on basic physicochemical properties. Then we designed amino-isonucleoside (isoA 1 , isoA 2 and isoT 1 ) incorporated siRNA 2-7. Some meaningful results have been obtained from the physicochemical property experiments in ASONs. In RNAi potency experiments, we investigated RNAi potency of each strand of the siRNA. These amino-isonucleosides incorporated siRNAs showed promising bioactivity properties and had position specificity. Reduced off target effect from sense strand loading in siRNA application was observed.

Cardiac sodium channel gene variants and sudden cardiac death in women.

BACKGROUND: Several cardiac ion channel genes have been implicated in monogenic traits with a high risk of sudden cardiac death (SCD). Mutations or rare variants in these genes have been proposed as potential contributors to more common forms of SCD, but this hypothesis has not been assessed systematically. METHODS AND RESULTS: We directly sequenced the entire coding region and splice junctions of 5 cardiac ion channel genes, SCN5A, KCNQ1, KCNH2, KCNE1, and KCNE2, in 113 SCD cases from 2 large prospective cohorts of women (Nurses' Health Study) and men (Health Professional Follow-Up Study). Controls from the same population were then screened for the presence of mutations or rare variants identified in cases, and sequence variants without prior functional data were expressed in Xenopus oocytes to assess their biophysical consequences. No mutations or rare variants were identified in any of the 53 subjects who were men. In contrast, in 6 of 60 women (10%), we identified 5 rare missense variants in SCN5A that either had been associated previously with long-QT syndrome (A572D and G615E), had been reported to alter sodium channel function (F2004L), or had not been reported previously in control populations (A572F and W1205C). Of the 4 variants without prior functional data, 3 variants were located in the I-II linker (A572D, A572F, and G615E), and all resulted in significantly shorter recovery times from inactivation. When compared with 733 control samples from the same population, the overall frequency of these rare variants in SCN5A was significantly higher in the SCD cases (6/60, 10.0%) than in controls (12/733, 1.6%; P=0.001). CONCLUSIONS: Functionally significant mutations and rare variants in SCN5A may contribute to SCD risk among women.

[Effect of 17beta-estradiol on Kv2.1 current and delayed rectifier potassium current in cultured rat hippocampal neurons].

AIM: To study the effects of 17beta-estradiol on Kv2.1 potassium channel current and delayed rectifier potassium current (IK) in cultured rat hippocampal neurons. METHODS: The effects of 17beta-estradiol on Kv2.1 channel current and IK in cultured rat hippocampal neurons were observed using the whole cell patch clamp techniques. RESULTS: 17beta-Estradiol was shown to reduce the amplitude of Kv2.1 current and IK in concentration-dependent manners. The IC50s of 17beta-estradiol blocking Kv2.1 and IK were 2.4 and 4.0 micromol x L(-1), respectively. 17beta-Estradiol (3 micromol x l(-1)) significantly shifted the steady-state activation and inactivation curves of Kv2.1 current to negative potentials. However, it only produced the shift of the steady-state activation curve of IK to the negative potential without effect on the steady-state inactivation of IK. CONCLUSION: 17beta-Estradiol inhibits Kv2.1 and IK of hippocampus at similar level. The inhibition of 17beta-estradiol on IK current may be partially via blocking Kv2.1 current.