Vacancy-induced catalytic mechanism for alcohol electrooxidation on nickel-based electrocatalyst.

Owing to outstanding performances, nickel-based electrocatalysts are commonly used in electrochemical alcohol oxidation reactions (AORs), and the active phase is usually vacancy-rich nickel oxide/hydroxide (NiOx Hy ) species. However, researchers are not aware of the catalytic role of atom vacancy in AORs. Here, we study vacancy-induced catalytic mechanisms for AORs on NiOx Hy species. As to AORs on oxygen-vacancy-poor ß-Ni(OH)2 , the only redox mediator is electrooxidation-induced electrophilic lattice oxygen species, which can only catalyze the dehydrogenation process (e.g., the electrooxidation of primary alcohol to carboxylic acid) instead of the C-C bond cleavage. Hence, vicinal diol electrooxidation reaction involving the C-C bond cleavage is not feasible with oxygen-vacancy-poor ß-Ni(OH)2 . Only through oxygen vacancy-induced adsorbed oxygen-mediated mechanism, can oxygen-vacancy-rich NiOx Hy species catalyze the electrooxidation of vicinal diol to carboxylic acid and formic acid accompanied with the C-C bond cleavage. Crucially, we examine how vacancies and vacancy-induced catalytic mechanisms work during AORs on NiOx Hy species.

Efficacy of low-intensity pulsed ultrasound in the treatment of COVID-19 pneumonia.

PURPOSE: As a public health emergency of international concern, coronavirus disease 2019 (COVID-19) still lacks specific antiviral drugs, and symptomatic treatment is currently the mainstay. The overactivated inflammatory response in COVID-19 patients is associated with a high risk of critical illness or even death. Low-intensity pulsed ultrasound (LIPUS) can mitigate inflammation and inhibit edema formation. We aimed to investigate the efficacy of LIPUS therapy for COVID-19 pneumonia. MATERIALS AND METHODS: 62 patients were randomly assigned to a treatment group (LIPUS treatment area - Group 1; self-control area - Group 2) and an external control group (Group 3). The primary outcomes were the volume absorption rate (VAR) and the area absorption rate (AAR) of lung inflammation in CT images. RESULTS: After an average duration of treatment 7.2 days, there were significant differences in AAR and VAR between Group 1 and Group 2 (AAR 0.25 vs 0.12, p=0.013; VAR 0.35 vs 0.11, p=0.005), and between Group 1 and Group 3 (AAR 0.25 vs 0.11, p=0.047; VAR 0.35 vs 0.19, p=0.042). Neither AAR nor VAR was statistically different between Group 2 and Group 3. After treatment, C-reactive protein, interleukin-6, leukocyte, and fingertip arterial oxygen saturation (SaO2) improved in Group 1, while in Group 3 only fingertip SaO2 increased. CONCLUSION: LIPUS therapy reduced lung inflammation and serum inflammatory factor levels in hospitalized COVID-19 patients, which might be a major advancement in COVID-19 pneumonia therapy.

Effect and underlying mechanisms of spirocyclopiperazinium salt compound DXL-A-24 in rats following spinal nerve ligation.

PURPOSE: Neuropathic pain represents a significant public health problem and its effective management remains a challenge. The present study is designed to evaluate the analgesic effect of the spirocyclopiperazinium salt compound DXL-A-24 in spinal nerve ligation (SNL) model, and further to explore the possible molecular mechanisms. METHODS: SNL model was established on rats, and mechanical allodynia and thermal hyperalgesia were estimated with the von Frey and hot plate tests; the expression of CaMKIIα, CREB, JAK2, STAT3 and c-fos was determined by western blotting; the protein level of TNF-α was analysed by ELISA; the mRNA expression of TNF-α and c-fos was detected using qRT-PCR analysis and the receptor blocking test was used for target searching. RESULTS: Administration of DXL-A-24 (1, 0.5, 0.25 mg/kg, i.g.) obviously relieved SNL-induced mechanical allodynia and thermal hyperalgesia in rats (P < 0.01), with the percentage of pain threshold elevation (PTE%) was 103 %, 68 % and 47 %, respectively, in mechanical allodynia; the percentage of maximal possible effect (MPE%) was 56 %, 34 % and 21 %, respectively, in thermal hyperalgesia on day 7 after SNL. Pretreatment with peripheral α7 nicotinic or M4 muscarinic receptor antagonist, the effect of DXL-A-24 was completely blocked (P > 0.05). DXL-A-24 significantly reduced the upregulated pCaMKIIα, pCREB, pJAK2, pSTAT3 and TNF-α protein (P < 0.01), which could be blocked by α7 nicotinic receptor or M4 muscarinic receptor antagonist. In addition, administration of DXL-A-24 attenuated the mRNA and protein expression of c-fos and TNF-α mRNA in DRG of SNL rat. We did not observe significant acute toxicity and chronic hepatorenal impairment at effective dose and high dose. CONCLUSIONS: We report firstly that administration of DXL-A-24 displays obvious antineuropathic pain effects in SNL rats. The underlying mechanism may involve the reduction of the CaMKIIα/CREB and JAK2/STAT3 signalling pathways, and the suppression of TNF-α and c-fos expression, which may be mediated by activating peripheral α7 nicotinic and M4 muscarinic receptors. This study may provide a new perspective for developing new antineuralgic drug.

Dexamethasone induces an imbalanced fetal-placental-maternal bile acid circulation: involvement of placental transporters.

BACKGROUND: The use of prenatal dexamethasone remains controversial. Our recent studies found that prenatal dexamethasone exposure can induce maternal intrahepatic cholestasis and have a lasting adverse influence on bile acid (BA) metabolism in the offspring. The purpose of this study was to investigate the effects of dexamethasone on fetal-placental-maternal BA circulation during the intrauterine period, as well as its placental mechanism. METHODS: Clinical data and human placentas were collected and analyzed. Pregnant Wistar rats were injected subcutaneously with dexamethasone (0.2 mg/kg per day) from gestational day 9 to 20. The metabolomic spectra of BAs in maternal and fetal rat serum were determined by LC-MS. Human and rat placentas were collected for histological and gene expression analysis. BeWo human placental cell line was treated with dexamethasone (20-500 nM). RESULTS: Human male neonates born after prenatal dexamethasone treatment showed an increased serum BA level while no significant change was observed in females. Moreover, the expression of organic anion transporter polypeptide-related protein 2B1 (OATP2B1) and breast cancer resistance protein (BCRP) in the male neonates' placenta was decreased, while multidrug resistance-associated protein 4 (MRP4) was upregulated. In experimental rats, dexamethasone increased male but decreased female fetal serum total bile acid (TBA) level. LC-MS revealed that primary BAs were the major component that increased in both male and female fetal serum, and all kinds of BAs were significantly increased in maternal serum. The expression of Oatp2b1 and Bcrp were reduced, while Mrp4 expression was increased in the dexamethasone-treated rat placentas. Moreover, dexamethasone increased glucocorticoid receptor (GR) expression and decreased farnesoid X receptor (FXR) expression in the rat placenta. In BeWo cells, dexamethasone induced GR translocation into the nucleus; decreased FXR, OATP2B1, and BCRP expression; and increased MRP4 expression. Furthermore, GR was verified to mediate the downregulation of OATP2B1, while FXR mediated dexamethasone-altered expression of BCRP and MRP4. CONCLUSIONS: By affecting placental BA transporters, dexamethasone induces an imbalanced fetal-placental-maternal BA circulation, as showed by the increase of primary BA levels in the fetal serum. This study provides an important experimental and theoretical basis for elucidating the mechanism of dexamethasone-induced alteration of maternal and fetal BA metabolism and for exploring early prevention and treatment strategies.

Electroacupuncture ameliorates beta-amyloid pathology and cognitive impairment in Alzheimer disease via a novel mechanism involving activation of TFEB (transcription factor EB).

Alzheimer disease (AD) is the most prevalent neurodegenerative disorder leading to dementia in the elderly. Unfortunately, no cure for AD is available to date. Increasing evidence has proved the roles of misfolded protein aggregation due to impairment of the macroautophagy/autophagy-lysosomal pathway (ALP) in the pathogenesis of AD, and thus making TFEB (transcription factor EB), which orchestrates ALP, as a promising target for treating AD. As a complementary therapy, acupuncture or electroacupuncture (EA) has been commonly used for treating human diseases. Although the beneficial effects of acupuncture for AD have been primarily studied both pre-clinically and clinically, the real efficacy of acupuncture on AD remains inconclusive and the underlying mechanisms are largely unexplored. In this study, we demonstrated the cognitive-enhancing effect of three-needle EA (TNEA) in an animal model of AD with beta-amyloid (Aß) pathology (5xFAD). TNEA reduced APP (amyloid beta (A4) precursor protein), C-terminal fragments (CTFs) of APP and Aß load, and inhibited glial cell activation in the prefrontal cortex and hippocampus of 5xFAD. Mechanistically, TNEA activated TFEB via inhibiting the AKT-MAPK1-MTORC1 pathway, thus promoting ALP in the brains. Therefore, TNEA represents a promising acupuncture therapy for AD, via a novel mechanism involving TFEB activation.Abbreviations Aß: ß-amyloid; AD: Alzheimer disease; AIF1/IBA1: allograft inflammatory factor 1; AKT1: thymoma viral proto-oncogene 1; ALP: autophagy-lysosomal pathway; APP: amyloid beta (A4) precursor protein; BACE1: beta-site APP cleaving enzyme 1; CQ: chloroquine; CTFs: C-terminal fragments; CTSD: cathepsin D; EA: electroacupuncture; FC: fear conditioning; GFAP: glial fibrillary acidic protein; HI: hippocampus; LAMP1: lysosomal-associated membrane protein 1; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MAPK1/ERK2: mitogen-activated protein kinase 1; MAPT: microtubule-associated protein tau; MTORC1: mechanistic target of rapamycin kinase complex 1; MWM: Morris water maze; NFT: neurofibrillary tangles; PFC: prefrontal cortex; PSEN1: presenilin 1; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB; TNEA: three-needle electroacupuncture.

Antinociceptive Effect of Spirocyclopiperazinium Salt Compound DXL-A-24 and the Underlying Mechanism.

The antinociceptive effects of spirocyclopiperazinium salt compound DXL-A-24 on neuropathic pain and chemical-stimulated pain were investigated in this study. After the administration of DXL-A-24, the paw withdrawal latency (PWL) and mechanical withdrawal threshold (MWT) were increased in rats suffering from neuropathic pain (chronic constriction injury, CCI) on days 1, 3, 5, 7 and 14 after surgery, and pain responses were inhibited in mice stimulated with chemicals (formalin or acetic acid). In the analysis of antinociceptive targets, the effect of DXL-A-24 was blocked by a peripheral nicotinic acetylcholine receptor (nAChR) antagonist (hexamethonium, Hex) or α7 nAChR antagonist (methyllycaconitine, MLA) in the formalin test. Meanwhile, the effect of DXL-A-24 was also blocked by a peripheral muscarinic acetylcholine receptor (mAChR) antagonist (atropine methylnitrate, Amn) or M4 mAChR antagonist (tropicamide, TRO). The antinociceptive signalling pathway was explored using molecular biology methods in ipsilateral dorsal root ganglions (DRGs) of CCI rats after the administration of DXL-A-24 for 7 days. Western blot analyses showed that the increased levels of phosphorylation of calcium/calmodulin-dependent protein kinase II alpha (CaMKIIα) and cAMP response element-binding protein (CREB) were eliminated, and the qRT-PCR assay showed that the increase in the expression of Tumor necrosis factor alpha (TNF-α) mRNA was reduced. Meanwhile, immunofluorescence staining revealed that the increase in calcitonin gene related peptide (CGRP) expression was inhibited by the administration of DXL-A-24, and the effect was blocked by MLA or TRO. In conclusion, DXL-A-24 exerts significant antinociceptive effects on neuropathic pain and chemical-stimulated pain. The antinociceptive effect of DXL-A-24 is probably attributed to the activation of peripheral α7 nAChR and M4 mAChR, the subsequent inhibition of the CaMKIIα/CREB signalling pathway, and finally the inhibition of TNF-α and CGRP expression.

Highly conductive and metallic cobalt-nickel selenide nanorods supported on Ni foam as an efficient electrocatalyst for alkaline water splitting.

Water splitting has long been considered as a promising chemical reaction that can produce clean hydrogen fuel to relieve the energy crisis and environmental pollution. Herein, we report that Co0.75Ni0.25Se/NF formed by two-step growth of metallic cobalt-nickel selenide nanorods on porous nickel foam was used as a bifunctional electrocatalyst. Ni foam serves as a slow-releasing nickel source together with a Co source to form a special proportional cobalt-nickel selenide. Due to its unique rough nanostructure, bimetallic cooperative effects and intrinsic metallic character, the obtained Co0.75Ni0.25Se/NF electrode exhibits a low overpotential of 269 mV (50 mA cm-2) for the oxygen evolution reaction and an overpotential of 106 mV (10 mA cm-2) for the hydrogen evolution reaction. Furthermore, this bifunctional electrocatalyst requires a cell voltage of 1.60 V to achieve a current density of 10 mA cm-2. Besides, based on theoretical calculation, it is further shown that the synergy between Co and Ni elements is beneficial for improving the internal structure of the catalyst, resulting in a high electrical conductivity, and low HER Gibbs free-energy and water adsorption energy. The present results indicate that Co0.75Ni0.25Se/NF exhibits advanced electrocatalytic activity for overall water splitting. This work offers an appropriate methodology and theoretical guidance to synthesize a bimetal-selenide electrocatalyst for water splitting.

Antinociception of the spirocyclopiperazinium salt compound LXM-15 via activating α7 nAChR and M4 mAChR and inhibiting CaMKIIα/cAMP/CREB/CGRP signalling pathway in mice.

The aim of this study was to investigate the analgesic effect of the spirocyclopiperazinium salt compound LXM-15 by intragastric administration in thermal and chemical pain models and further to elucidate the possible molecular mechanisms. The results showed that LXM-15 exerted significant antinociception in hot-plate test, formalin test and acetic acid writhing test. Western blot analysis showed that LXM-15 significantly reduced the upregulation of phosphorylation of calcium/calmodulin -dependent protein kinase IIα (CaMKIIα) and cAMP response element-binding protein (CREB), and further decreased the elevation of calcitonin gene related peptide (CGRP) in the dorsal root ganglion (DRG) and spinal cord in mice. ELISA analysis showed the level of cAMP in the spinal cord was decreased by LXM-15. All effects of LXM-15 could be blocked by methyllycaconitine citrate (MLA, a selective α7 nicotinic receptor antagonist) or tropicamide (TRO, a selective M4 muscarinic receptor antagonist). This study first reported that intragastric administration of LXM-15 produced significant analgesic effect, which may be related to the activation of α7 nicotinic acetylcholine receptor and M4 muscarine acetylcholine receptor, and thereby inhibiting CaMKIIα/cAMP/CREB/CGRP signalling pathway.

Anti-inflammatory effect and mechanism of the spirocyclopiperazinium salt compound LXM-15 in rats and mice.

OBJECTIVE: This study aimed to investigate the anti-inflammatory effects of a novel spirocyclopiperazinium salt compound LXM-15, and explore the underlying mechanisms. METHODS: Xylene-induced mouse ear oedema and carrageenan-induced rat paw oedema tests were used to evaluate the anti-inflammatory effects of LXM-15. The protein levels of TNF-α, IL-6, phosphorylation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) were detected by ELISA or Western blot analysis. Additionally, receptor blocking test was performed to explore the possible target. RESULTS: Intragastric administration with LXM-15 (2, 1, 0.5 mg/kg in mice, and 6, 3, 1.5 mg/kg in rats) produced distinct anti-inflammatory effects in vivo, the highest inhibition percentage was 60 and 52%, respectively (P < 0.01). Following treatment with LXM-15 (6 mg/kg, i.g.), the levels of TNF-α and IL-6 in the rats paws were attenuated by 40 and 41%; and the phosphorylation of JAK2 and STAT3 was restrained by 35 and 45%, respectively (P < 0.01). All effects of LXM-15 were blocked by pretreatment with methyllycaconitine citrate or tropicamide. CONCLUSION: This study provides the first report that the spirocyclopiperazinium salt compound LXM-15 displays considerable anti-inflammatory effects. The underlying mechanism may be through activating the peripheral α7 nicotinic acetylcholine receptor and M4 muscarinic acetylcholine receptor, leading to the inhibition of the JAK2/STAT3 signalling pathway, eventually resulting in the reduction of TNF-α and IL-6.

Apratoxin A Shows Novel Pancreas-Targeting Activity through the Binding of Sec 61.

Apratoxin A is a natural product with potent antiproliferative activity against many human cancer cell lines. However, we and other investigators observed that it has a narrow therapeutic window in vivo Previous mechanistic studies have suggested its involvement in the secretory pathway as well as the process of chaperone-mediated autophagy. Still the link between the biologic activities of apratoxin A and its in vivo toxicity has remained largely unknown. A better understanding of this relationship is critically important for any further development of apratoxin A as an anticancer drug. Here, we describe a detailed pathologic analysis that revealed a specific pancreas-targeting activity of apratoxin A, such that severe pancreatic atrophy was observed in apratoxin A-treated animals. Follow-up tissue distribution studies further uncovered a unique drug distribution profile for apratoxin A, showing high drug exposure in pancreas and salivary gland. It has been shown previously that apratoxin A inhibits the protein secretory pathway by preventing cotranslational translocation. However, the molecule targeted by apratoxin A in this pathway has not been well defined. By using a (3)H-labeled apratoxin A probe and specific Sec 61α/ß antibodies, we identified that the Sec 61 complex is the molecular target of apratoxin A. We conclude that apratoxin A in vivo toxicity is likely caused by pancreas atrophy due to high apratoxin A exposure. Mol Cancer Ther; 15(6); 1208-16. ©2016 AACR.

Anti-inflammation of spirocyclopiperazinium salt compound LXM-10 targeting α7 nAChR and M4 mAChR and inhibiting JAK2/STAT3 pathway in rats.

The present study aims to investigate the therapeutic effects of LXM-10 by intragastric administration in both acute and chronic inflammatory models, and to explore the underlying molecular mechanisms. The results showed that LXM-10 produced significant anti-inflammatory effects on carrageenan induced paw edema and complete Freund's adjuvant (CFA) induced arthritis, in which LXM-10 inhibited paw swelling in a dose- and time-dependent manner. ELISA analysis showed the production of pro-inflammatory cytokines including TNF-α and IL-6 was decreased by LXM-10. Western blot analysis showed that LXM-10 significantly reduced phosphorylation of Janus kinase 2 (JAK2) and further blunted phosphorylation of signal transducer and activator of transcription-3 (STAT3). The effects that LXM-10 had shown were attenuated by methyllycaconitine citrate (an α7 nicotinic acetylcholine receptor antagonist) or tropicamide (an M4 muscarinic acetylcholine receptor antagonist) in vivo. In conclusion, the studies showed that intragastric administration of LXM-10 exerted significant anti-inflammation effects in acute and chronic models, which may be attribute to the activation of α7 nicotinic acetylcholine receptor and M4 muscarinic acetylcholine receptor, thereby inhibiting the JAK2/STAT3 signal pathway, and ultimately reducing the production of pro-inflammatory cytokines of TNF-α and IL-6.

Novel second generation analogs of eribulin. Part I: Compounds containing a lipophilic C32 side chain overcome P-glycoprotein susceptibility.

Eribulin mesylate (Halaven™), a totally synthetic analog of the marine polyether macrolide halichondrin B, has recently been approved in the United States as a treatment for breast cancer. It is also currently under regulatory review in Japan and the European Union. Our continuing medicinal chemistry efforts on this scaffold have focused on oral bioavailability, brain penetration and efficacy against multidrug resistant (MDR) tumors by lowering the susceptibility of these compounds to P-glycoprotein (P-gp)-mediated drug efflux. Replacement of the 1,2-amino alcohol C32 side chain of eribulin with fragments neutral at physiologic pH led to the identification of analogs with significantly lower P-gp susceptibility. The analogs maintained low- to sub-nM potency in vitro against both sensitive and MDR cell lines. Within this series, increasing lipophilicity generally led to decreased P-gp susceptibility. In addition to potency in cell culture, these compounds showed in vivo activity in mouse xenograft models.

Novel second generation analogs of eribulin. Part III: Blood-brain barrier permeability and in vivo activity in a brain tumor model.

Novel second generation analogs of eribulin mesylate, a tubulin agent recently approved for the treatment of breast cancer, are reported. Our recent efforts have focused on expanding the target indications for this class of compounds to other tumor types. Herein, we describe the design, synthesis and evaluation of eribulin analogs active against brain tumor cell lines in vitro and corresponding brain tumor models in mice. Attenuation of basicity of the amino group(s) in the C32 side-chain region led to compounds with lower susceptibility to P-gp mediated drug efflux, allowing these compounds to permeate through the blood-brain barrier. In preclinical in vivo studies, these compounds showed significantly higher levels in the brain and cerebrospinal fluid as compared to eribulin. In addition, analogs within this series showed antitumor activity in an orthotopic murine model of human glioblastoma.

Novel second generation analogs of eribulin. Part II: Orally available and active against resistant tumors in vivo.

Eribulin mesylate is a newly approved treatment for locally advanced and metastatic breast cancer. We targeted oral bioavailability and efficacy against multidrug resistant (MDR) tumors for further work. The design, synthesis and evaluation of novel amine-containing analogs of eribulin mesylate are described in this part. Attenuation of basicity of the amino group(s) in the C32 side-chain region led to compounds with low susceptibility to PgP-mediated drug efflux. These compounds were active against MDR tumor cell lines in vitro and in xenograft models in vivo, in addition to being orally bioavailable.

Anti-inflammatory effect of the spirocyclopiperazinium compound LXM-10 in mice and rats.

Anti-inflammatory drugs are clinically limited because of their side effects. The aim of this study was to evaluate the anti-inflammatory activities and mechanisms of the spirocyclopiperazinium compound LXM-10 (2, 4-dimethyl-9-beta-phenylethyl-3-oxo-6, 9-diazaspiro[5.5]undecane chloride). We found that LXM-10 produced a significant, dose-dependent decrease in xylene- and carrageenin-induced edema. The anti-inflammatory effect was attenuated by hexamethonium, methyllycaconitine citrate, atropine methylnitrate, and tropicamide. The serum level of TNF-alpha was reduced by LXM-10 in lipopolysaccharide-challenged mice, and this effect was also inhibited by methyllycaconitine and tropicamide. LXM-10 also reduced the prostaglandin E(2) concentration in rat paw tissue. LXM-10 minimised the carrageenin-induced pathological changes and did not affect mice heart rate. LXM-10 did not induce significant changes in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) or alkaline phosphatase (ALP) activity. Median lethal dose (LD(50)) of LXM-10 was 1573.0 micromol/kg. Our findings suggest that LXM-10 has anti-inflammatory effects by activating alpha7 nicotinic and M(4) muscarinic acetylcholine receptors with limited side effects.

Anti-tumor effect of Liqi, a traditional Chinese medicine prescription, in tumor bearing mice.

BACKGROUND: Liqi, an herbal preparation used in traditional Chinese medicine, has been used to treat cancer in China for centuries. We investigated the anti-tumor effects of liqi and their mechanisms in mice that had been xenografted with tumors. METHODS: Sarcoma 180 tumor, Lewis lung carcinoma, and SGC-7901 cells were implanted in BALB/c mice, C57BL/6 mice, and BALB/c nude mice, respectively. Liqi was administered to subgroups of these mice. The tumor weight and size were measured. Cell cycle analysis and T lymphocyte subsets were determined by flow cytometry. The activity of NK cells and TNF was tested using cytotoxicity assay on YAC-1 cells and L929 cells, respectively, and the activity of IL-2 was tested with an IL-2-dependent CTLL-2 cell proliferation assay. Platelet aggregation was monitored by measuring electric impedance, and the levels of thromboxane A2 (TXA2) and prostacyclin (PGI2) in blood were measured by 125I-TXB2 and 125I-Keto-PGF1alpha radioimmunoassay. RESULTS: The results showed that liqi inhibited tumor growth in tumor-implanted mice and arrested the cell proliferation in the G0/G1 phase and reduced the portion of cells in S and G2/M phase for SGC-7901 cells. Liqi increased the activity of NK cells and TNF-alpha, stimulated IL-2 production and activity, and regulated T lymphocyte subpopulations. Liqi inhibited the Lewis lung carcinoma metastasis by inhibiting platelet aggregation and normalizing the balance between TXA2 and PGI2. CONCLUSION: All these findings demonstrated that liqi has an anti-tumor effect in vivo. The mechanism may be related to immune regulation and anticoagulation effects.

Potent in vitro and in vivo anticancer activities of des-methyl, des-amino pateamine A, a synthetic analogue of marine natural product pateamine A.

We report here that des-methyl, des-amino pateamine A (DMDA-PatA), a structurally simplified analogue of the marine natural product pateamine A, has potent antiproliferative activity against a wide variety of human cancer cell lines while showing relatively low cytotoxicity against nonproliferating, quiescent human fibroblasts. DMDA-PatA retains almost full in vitro potency in P-glycoprotein-overexpressing MES-SA/Dx5-Rx1 human uterine sarcoma cells that are significantly resistant to paclitaxel, suggesting that DMDA-PatA is not a substrate for P-glycoprotein-mediated drug efflux. Treatment of proliferating cells with DMDA-PatA leads to rapid shutdown of DNA synthesis in the S phase of the cell cycle. Cell-free studies show that DMDA-PatA directly inhibits DNA polymerases α and γ in vitro albeit at concentrations considerably higher than those that inhibit cell proliferation. DMDA-PatA shows potent anticancer activity in several human cancer xenograft models in nude mice, including significant regressions observed in the LOX and MDA-MB-435 melanoma models. DMDA-PatA thus represents a promising natural product-based anticancer agent that warrants further investigation.

Bis[2-(2-pyridylmethyl-eneamino)benzene-sulfonato-κN,N',O]manganese(II) dihydrate.

The title complex, [Mn(C(12)H(9)N(2)O(3)S)(2)]·2H(2)O, is isotypic with the previously reported Zn(II) and Cd(II) species. The complex was prepared by the reaction of the potassium salt of 2-(2-pyridylmethyl-eneamino)benzene-sulfonic acid with MnCl(2)·6H(2)O in methanol. The complex displays twofold symmetry, with the ligands coordinated in a tridentate meridional-like arrangement through pyridyl N, imine N, and sulfonate O atoms. The metal center has a strongly distorted octa-hedral coordination geometry. The uncoordin-ated water mol-ecules and the complexes participate in a hydrogen-bonding network, forming a two-dimensional structure parallel to the ab plane.

Bis[2-(2-pyridylmethyl-eneamino)benzene-sulfonato]-κN,N',O;κN,N'-copper(II).

In the mononuclear title compound, [Cu(C(12)H(9)N(2)O(3)S)(2)], the copper(II) salt of 2-(2-pyridylmethyl-eneamino)benzene-sulfonic acid, the Cu(II) atom is coordinated by one O and two N atoms from a monoanion as well as by two N atoms from another monoanion in a distorted trigonal-bipyramidal environment.

Bis[2-(2-pyridylmethyl-eneamino)benzene-sulfonato-κN,N',O]cobalt(II) dihydrate.

The title complex, [Co(C(12)H(9)N(2)O(3)S)(2)]·2H(2)O, has site symmetry 2 with the Co(II) cation located on a twofold rotation axis. Two tridentate 2-(2-pyridylmethyl-eneamino)benzene-sulfonate (paba) ligands chelate to the Co(II) cation in a distorted octa-hedral geometry. The pyridine and benzene rings in the paba ligand are oriented at a dihedral angle of 42.86 (13)°. Inter-molecular O-H⋯O and C-H⋯O hydrogen bonding is present in the crystal structure.