SEA0400, a novel and selective inhibitor of the Na+-Ca2+ exchanger, attenuates reperfusion injury in the in vitro and in vivo cerebral ischemic models.

The effect of the newly synthesized compound 2-[4-[(2,5-difluorophenyl)methoxy]phenoxy]-5-ethoxyaniline (SEA0400) on the Na+-Ca2+ exchanger (NCX) was investigated and compared against that of 2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea (KB-R7943). In addition, the effects of SEA0400 on reperfusion injury in vitro and in vivo were examined. SEA0400 was extremely more potent than KB-R7943 in inhibiting Na+-dependent Ca2+ uptake in cultured neurons, astrocytes, and microglia: IC50s of SEA0400 and KB-R7943 were 5 to 33 nM and 2 to 4 microM, respectively. SEA0400 at the concentration range that inhibited NCX exhibited negligible affinities for the Ca2+ channels, Na+ channels, K+ channels, norepinephrine transporter, and 14 receptors, and did not affect the activities of the Na+/H+ exchanger, Na+,K+-ATPase, Ca2+-ATPase, and five enzymes. SEA0400, unlike KB-R7943, did not inhibit the store-operated Ca2+ entry in cultured astrocytes. SEA0400 attenuated dose- dependently paradoxical Ca2+ challenge-induced production of reactive oxygen species, DNA ladder formation, and nuclear condensation in cultured astrocytes, whereas it did not affect thapsigargin-induced cell injury. Furthermore, administration of SEA0400 reduced infarct volumes after a transient middle cerebral artery occlusion in rat cerebral cortex and striatum. These results indicate that SEA0400 is the most potent and selective inhibitor of NCX, and suggest that the compound may exert protective effects on postischemic brain damage.     

大剂量茶多酚加重实验性心肌缺血性损伤

目的旨在研究大剂量茶多酚对实验性心肌缺血性损伤的影响，以进一步明确茶多酚对心血管系统的作用及其剂量～效应关系。方法健康家兔１４只，随机分为对照组（８只）和实验组（６只）。经静脉注射乌拉坦（１．０ｇ／ｋｇ）麻醉实验动物后，记录体表标准Ⅱ导联心电图，气管插管后开胸暴露心脏，在左室支主干上、中１／３交界处穿线备用。稳定１５ｍｉｎ后，对照组经耳缘静脉注射生理盐水１０ｍｌ，实验组则给予茶多酚溶液１０ｍｌ（剂量为５０ｍｇ／ｋｇ）。３０ｍｉｎ后结扎左室支，持续１５ｍｉｎ。缺血期由专人连续观察（必要时记录）实验动物的体表心电图变化。结果实验组缺血期心律失常的发生率为８３．３％（５／６），显著高于对照组的１２．５％（１／８，Ｐ＜０．０５）。实验组缺血期的动物死亡率为８３．３％（５／６），亦显著高于对照组的０（Ｐ＜０．０５）。结论静脉注射大剂量茶多酚可加重实验性心肌缺血性损伤     

SSR182289A,a novel,orally active thrombin inhibitor: in vitro profile and ex vivo anticoagulant activity

SSR182289A competitively inhibits human thrombin (K(i) = 0.031 +/- 0.002 microM) and shows good selectivity with respect to other human proteases, e.g., trypsin (K(i) = 54 +/- 2 microM), factor Xa (K(i) = 167 +/- 9 microM), and factor VIIa, factor IXa, plasmin, urokinase, tPA, kallikrein, and activated protein C (all K(i) values >250 microM). In human plasma, SSR182289A demonstrated anticoagulant activity in vitro as measured by standard clotting parameters (EC100 thrombin time 96 +/- 7 nM) and inhibited tissue factor-induced thrombin generation (IC50 of 0.15 +/- 0.02 microM). SSR182289A inhibited thrombin-induced aggregation of human platelets with an IC50 value of 32 +/- 9 nM, but had no effect on aggregation induced by other platelet agonists. The anticoagulant effects of SSR182289A were studied by measuring changes in coagulation markers ex vivo after i.v. or oral administration in several species. In dogs, SSR182289A (0.1-1 mg/kg i.v. and 1-5 mg/kg p.o.) produced dose-related increases in clotting times. After oral dosing, maximum anticoagulant effects were observed 2 h after administration with increases in thrombin time, 2496 +/- 356%; ecarin clotting time (ECT), 1134 +/- 204%; and activated partial thromboplastin time (aPTT), 91 +/- 20% for the dose of 3 mg/kg p.o., and thrombin time, 3194 +/- 425%; ECT, 2017 +/- 341%; and aPTT, 113 +/- 9% after 5 mg/kg p.o. Eight hours after administration of 3 or 5 mg/kg SSR182289A, clotting times were still elevated. SSR182289A also showed oral anticoagulant activity in rat, rabbit, and macaque. Hence, SSR182289A is a potent, selective, and orally active thrombin inhibitor.     

microRNA与心肌缺血损伤研究新进展

背景:研究发现多种microRNA在心肌缺血缺氧时表达明显异常,它们对心血管疾病的发生和发展起着重要作用。目的:介绍近5年来microRNA对心肌缺血损伤的影响、作用机制及可能的治疗方案。方法:分别以"microRNA、心肌、缺血、缺氧"为检索词,应用计算机检索PubMed数据库和ISIWeb of Knowledge平台检索近5年有关文章,排除与研究目的无关和内容重复者,保留42篇文献做进一步分析。结果与结论:microRNA是一类具有转录后调节活性的内源性小分子RNA,通过与靶mRNA的3`端非编码区结合负性调控基因的表达而参与心血管疾病的发生发展。目前研究表明microRNA参与了心肌缺血、缺血后心脏重塑、心肌梗死后继发性心律失常等相关的病理过程,人工干预microRNA的表达可以加剧或预防心肌缺血缺氧损伤的进展。microRNA可能成为治疗心血管疾病的靶向分子。     

microRNA与心肌缺血损伤研究新进展

背景：研究发现多种microRNA在心肌缺血缺氧时表达明显异常,它们对心血管疾病的发生和发展起着重要作用.目的：介绍近5年来microRNA对心肌缺血损伤的影响、作用机制及可能的治疗方案.方法：分别以＂microRNA、心肌、缺血、缺氧＂为检索词,应用计算机检索PubMed 数据库和ISI Web of Knowledge平台检索近5年有关文章,排除与研究目的无关和内容重复者,保留42篇文献做进一步分析.结果与结论：microRNA是一类具有转录后调节活性的内源性小分子RNA,通过与靶mRNA的3端非编码区结合负性调控基因的表达而参与心血管疾病的发生发展.目前研究表明microRNA参与了心肌缺血、缺血后心脏重塑、心肌梗死后继发性心律失常等相关的病理过程,人工干预microRNA的表达可以加剧或预防心肌缺血缺氧损伤的进展.microRNA可能成为治疗心血管疾病的靶向分子.     

PM-20, a novel inhibitor of Cdc25A, induces extracellular signal-regulated kinase 1/2 phosphorylation and inhibits hepatocellular carcinoma growth in vitro and in vivo

We have synthesized several new phenyl maleimide compounds, which are potent growth inhibitors of several human tumor cell lines. Among these, PM-20 was the most potent with an IC50 of 700 nmol/L for Hep3B human hepatoma cell growth. Two other derivatives, PM-26 and PM-38, did not inhibit Hep3B cell growth even at 100 micromol/L. Interestingly, under identical experimental conditions, PM-20 inhibited DNA synthesis of primary cultures of normal hepatocytes at a 10-fold higher concentration than that needed to inhibit the DNA synthesis of the Hep3B hepatoma cells. PM-20 affected two cellular signaling pathways in Hep3B cells: Cdc25 phosphatase and extracellular signal-regulated kinase (ERK) 1/2. It competitively inhibited the activity of Cdc25 (preferentially Cdc25A) by binding to the active site, likely through the catalytic cysteine, but did not inhibit PTP1B, CD45, or MKP-1 phosphatases. As a result of its action, tyrosine phosphorylation of the cellular Cdc25A substrates Cdk2 and Cdk4 was induced. It also induced strong and persistent phosphorylation of the Cdc25A substrate ERK1/2. Hep3B cell lysates were found to contain ERK2 phosphatase(s) activity, which was inhibited by the actions of PM-20. However, activity of exogenous dual-specificity ERK2 phosphatase MKP1 was not inhibited. Induction of ERK1/2 phosphorylation correlated with the potency of growth inhibition in tumor cell lines and inhibition of ERK1/2 phosphorylation by the mitogen-activated protein kinase (MAPK)/ERK kinase 1/2 inhibitor U0126 or overexpression of the cdc25A gene in Hep3B cells antagonized the growth inhibitory actions of PM-20. Growth of transplantable rat hepatoma cells in vivo was also inhibited by PM-20 action with a concomitant induction of pERK in the tumors. The mechanism(s) of growth inhibition of Hep3B hepatoma cells by the phenyl maleimide PM-20 involves prolonged ERK1/2 phosphorylation, likely resulting from inhibition of the ERK phosphatase Cdc25A. PM-20 thus represents a novel class of tumor growth inhibitor that inhibits mainly Cdc25A, is dependent on ERK activation, and has a considerable margin of selectivity for tumor cells compared with normal cells.     

MGCD0103, a novel isotype-selective histone deacetylase inhibitor, has broad spectrum antitumor activity in vitro and in vivo

Nonselective inhibitors of human histone deacetylases (HDAC) are known to have antitumor activity in mice in vivo, and several of them are under clinical investigation. The first of these, Vorinostat (SAHA), has been approved for treatment of cutaneous T-cell lymphoma. Questions remain concerning which HDAC isotype(s) are the best to target for anticancer activity and whether increased efficacy and safety will result with an isotype-selective HDAC inhibitor. We have developed an isotype-selective HDAC inhibitor, MGCD0103, which potently targets human HDAC1 but also has inhibitory activity against HDAC2, HDAC3, and HDAC11 in vitro. In intact cells, MGCD0103 inhibited only a fraction of the total HDAC activity and showed long-lasting inhibitory activity even upon drug removal. MGCD0103 induced hyperacetylation of histones, selectively induced apoptosis, and caused cell cycle blockade in various human cancer cell lines in a dose-dependent manner. MGCD0103 exhibited potent and selective antiproliferative activities against a broad spectrum of human cancer cell lines in vitro, and HDAC inhibitory activity was required for these effects. In vivo, MGCD0103 significantly inhibited growth of human tumor xenografts in nude mice in a dose-dependent manner and the antitumor activity correlated with induction of histone acetylation in tumors. Our findings suggest that the isotype-selective HDAC inhibition by MGCD0103 is sufficient for antitumor activity in vivo and that further clinical investigation is warranted.     

A translation inhibitor that suppresses dengue virus in vitro and in vivo

We describe a novel translation inhibitor that has anti-dengue virus (DENV) activity in vitro and in vivo. The inhibitor was identified through a high-throughput screening using a DENV infection assay. The compound contains a benzomorphan core structure. Mode-of-action analysis indicated that the compound inhibits protein translation in a viral RNA sequence-independent manner. Analysis of the stereochemistry demonstrated that only one enantiomer of the racemic compound inhibits viral RNA translation. Medicinal chemistry was performed to eliminate a metabolically labile glucuronidation site of the compound to improve its in vivo stability. Pharmacokinetic analysis showed that upon a single subcutaneous dosing of 25 mg/kg of body weight in mice, plasma levels of the compound reached a C(max) (maximum plasma drug concentration) above the protein-binding-adjusted 90% effective concentration (EC(90)) value of 0.96 μM. In agreement with the in vivo pharmacokinetic results, treatment of DENV-infected mice with 25 mg/kg of compound once per day reduced peak viremia by about 40-fold. However, mice treated with 75 mg/kg of compound per day exhibited adverse effects. Collectively, our results demonstrate that the benzomorphan compounds inhibit DENV through suppression of RNA translation. The therapeutic window of the current compounds needs to be improved for further development.     

In vitro and in vivo pharmacokinetics-pharmacodynamics of GV143253A,a novel trinem

The aim of the present study was to characterize the pharmacokinetic-pharmacodynamic relationship of GV143253A, a novel trinem anti-methicillin-resistant Staphylococcus aureus (MRSA) agent active against gram-positive cocci, including multidrug-resistant clinical isolates. An in vitro pharmacodynamic study with methicillin-susceptible S. aureus (MSSA) and MRSA has shown that the duration of exposure to GV143253A rather than its concentration is the major determinant of the extent of bacterial killing. The in vitro findings were confirmed by use of a neutropenic murine model of thigh infection caused by MSSA ATCC 25923. From the dose-response curves, the static doses extrapolated for three different dosing intervals showed that more frequent dosing of GV143253A was more effective than less frequent dosing. A pharmacokinetic-pharmacodynamic analysis demonstrated that only the time during which the drug concentration exceeded the MIC (t>MIC) correlated with in vivo GV143253A activity. The value of t>MIC required to achieve a bacteriostatic effect in a thigh infection of neutropenic animals was 20% (95% confidence interval [CI], 18 to 22%) of the dosing interval. This result is similar to those reported in the literature for carbapenems and for GV104326A, another novel trinem compound. In addition, in order to compare the therapeutic efficacy of GV143253A to that of vancomycin in a thigh infection caused by MRSA in immunocompetent mice, suitable dosing regimens were designed on the basis of previous pharmacokinetic-pharmacodynamic findings for GV143253A and on the human pharmacokinetic profile of the glycopeptide. Although the pharmacokinetic profiles of the two agents were completely different, GV143253A showed good efficacy comparable to that of vancomycin, reducing by 4 log units the bacterial counts in the thighs of treated mice relative to untreated infected animals after 48 h of therapy. The results suggest that if the time of exposure to the pathogen above the MIC is at least 30% of the dosing interval, GV143253A could have a role in the clinical treatment of infections caused by MRSA, which is difficult to eradicate with current antibiotics.     

KD5170, a novel mercaptoketone-based histone deacetylase inhibitor that exhibits broad spectrum antitumor activity in vitro and in vivo

Histone deacetylase (HDAC) inhibitors have garnered significant attention as cancer drugs. These therapeutic agents have recently been clinically validated with the market approval of vorinostat (SAHA, Zolinza) for treatment of cutaneous T-cell lymphoma. Like vorinostat, most of the small-molecule HDAC inhibitors in clinical development are hydroxamic acids, whose inhibitory activity stems from their ability to coordinate the catalytic Zn2+ in the active site of HDACs. We sought to identify novel, nonhydroxamate-based HDAC inhibitors with potentially distinct pharmaceutical properties via an ultra-high throughput small molecule biochemical screen against the HDAC activity in a HeLa cell nuclear extract. An alpha-mercaptoketone series was identified and chemically optimized. The lead compound, KD5170, exhibits HDAC inhibitory activity with an IC50 of 0.045 micromol/L in the screening biochemical assay and an EC50 of 0.025 micromol/L in HeLa cell-based assays that monitor histone H3 acetylation. KD5170 also exhibits broad spectrum classes I and II HDAC inhibition in assays using purified recombinant human isoforms. KD5170 shows significant antiproliferative activity against a variety of human tumor cell lines, including the NCI-60 panel. Significant tumor growth inhibition was observed after p.o. dosing in human HCT-116 (colorectal cancer), NCI-H460 (non-small cell lung carcinoma), and PC-3 (prostate cancer) s.c. xenografts in nude mice. In addition, a significant increase in antitumor activity and time to end-point occurred when KD5170 was combined with docetaxel in xenografts of the PC-3 prostate cancer cell line. The biological and pharmaceutical profile of KD5170 supports its continued preclinical and clinical development as a broad spectrum anticancer agent.     

A1-receptor blockade: a novel approach for assessing myocardial viability in chronic ischemic cardiomyopathy.

Diminished myocardial function can be seen in chronic coronary stenosis (CS) even in the presence of normal resting myocardial blood flow. We hypothesized that adenosine contributes to myocardial depression in this setting, predominantly through activation of the A(1) adenosine receptor. To test this hypothesis we used aminophylline, a nonselective adenosine receptor antagonist, and 8-cyclopentyl 1,3 dipropylxanthine, a selective A(1) adenosine receptor antagonist, in a canine model of chronic CS. Chronic CS was produced by placement of ameroid constrictors on the left anterior descending and left circumflex coronary arteries in 17 adult mongrel dogs, which resulted in severe left ventricular dysfunction 6 weeks later. Eight dogs without ameroid placement were used as controls (C). Closed-chest echocardiographic short-axis images at the low midpapillary level, hemodynamics, and radiolabeled microsphere-derived myocardial blood flow were obtained before and immediately after injection of either 5 mg/kg(-1) of aminophylline (7 left ventricular dysfunction and 4 C dogs) or 1 mg/kg(-1) of 8-cyclopentyl 1,3-dipropylxanthine (10 left ventricular dysfunction and 4 C dogs). Both 8-cyclopentyl 1,3-dipropylxanthine and aminophylline had no effect in C animals but resulted in a significant transient increase in regional percent wall thickening (P <.05) with a concomitant decrease in end-systolic wall stress (P <.05) in CS animals. There was no change in transmural myocardial blood flow or systemic hemodynamics to explain these results. Thus, adenosine plays a significant role in myocardial dysfunction in chronic ischemia by activation of the A(1) receptor. Aminophylline or a selective A(1) adenosine receptor antagonist can be used to detect viable myocardium and may be safer than dobutamine in severe chronic ischemic heart disease.     

A small-molecule inhibitor of glucose transporter 1 downregulates glycolysis, induces cell-cycle arrest, and inhibits cancer cell growth in vitro and in vivo

The functional and therapeutic importance of the Warburg effect is increasingly recognized, and glycolysis has become a target of anticancer strategies. We recently reported the identification of a group of novel small compounds that inhibit basal glucose transport and reduce cancer cell growth by a glucose deprivation-like mechanism. We hypothesized that the compounds target Glut1 and are efficacious in vivo as anticancer agents. Here, we report that a novel representative compound WZB117 not only inhibited cell growth in cancer cell lines but also inhibited cancer growth in a nude mouse model. Daily intraperitoneal injection of WZB117 at 10 mg/kg resulted in a more than 70% reduction in the size of human lung cancer of A549 cell origin. Mechanism studies showed that WZB117 inhibited glucose transport in human red blood cells (RBC), which express Glut1 as their sole glucose transporter. Cancer cell treatment with WZB117 led to decreases in levels of Glut1 protein, intracellular ATP, and glycolytic enzymes. All these changes were followed by increase in ATP-sensing enzyme AMP-activated protein kinase (AMPK) and declines in cyclin E2 as well as phosphorylated retinoblastoma, resulting in cell-cycle arrest, senescence, and necrosis. Addition of extracellular ATP rescued compound-treated cancer cells, suggesting that the reduction of intracellular ATP plays an important role in the anticancer mechanism of the molecule. Senescence induction and the essential role of ATP were reported for the first time in Glut1 inhibitor-treated cancer cells. Thus, WZB117 is a prototype for further development of anticancer therapeutics targeting Glut1-mediated glucose transport and glucose metabolism. Mol Cancer Ther; 11(8); 1672-82. ?2012 AACR.     

Calpain inhibitor I reduces intestinal ischemia-reperfusion injury in the rat

In this study we evaluated the effect of calpain inhibitor I on splanchnic artery occlusion (SAO) shock-mediated injury. SAO shock was induced in rats by clamping both the superior mesenteric artery and the celiac trunk for 45 min. After 1 h of reperfusion, SAO-shocked rats developed a significant fall in mean arterial blood pressure. Western blot analysis of ileum revealed a marked decrease in of IkappaB-alpha expression, and immunohistochemical examination of necrotic ileum demonstrated a marked increase in the immunoreactivity to P-selectin, intracellular adhesion molecule (ICAM-1), nitrotyrosine formation, and nuclear enzyme poly[adenosine diphosphate (ADP)-ribose] synthase (PARS) activation. An increase in myeloperoxidase activity (143 +/- 22 4.5 U/100 mg wet tissue vs. 4.5 +/- 2.5 U/100 mg wet tissue of sham-operated rats) and in malondialdehyde levels (13.12 +/- 1.2 micromol/100 mg wet tissue vs. 3.9 +/- 1.1 micromol/100 mg wet tissue of sham-operated rats) was also observed in rats subjected to ischemia-reperfusion injury. Calpain inhibitor I, given intraperitoneally 30 min before ischemia at a dose of 15 mg/kg, significantly improved mean arterial blood pressure, markedly reduced IkappaB-alpha degradation and the intensity of P-selectin and ICAM-1 in the reperfused ileum. Calpain inhibitor I also significantly prevented neutrophil infiltration (32.95 +/- 9.82 U/100 mg wet tissue), reduced malondialdehyde levels (6.76 +/- 0.98 micromol/100 mg wet tissue) and markedly improved the histological status of the reperfused tissue. In conclusion, this study demonstrates that calpain inhibitor I exerts multiple protective effects in splanchnic artery occlusion-reperfusion shock and suggests that calpain inhibitor I may be a candidate for consideration as a therapeutic intervention for ischemia-reperfusion injury.     

Estrogen reduces cardiac injury and expression of beta1-adrenoceptor upon ischemic insult in the rat heart

To test the hypothesis that estrogen confers cardioprotection by suppressing the expression of beta-adrenoceptor (beta-AR), we first correlated the infarct size in response to ischemic insult and beta-AR stimulation with the expression of beta(1)-AR in sham, ovariectomized (Ovx) and estrogen replaced (Ovx + E(2)) rats. When beta-AR is being activated during ischemia, the infarct size was significantly greater in Ovx than in the sham and Ovx + E(2) rats. There is a negative correlation between the infarct size and the expression level of beta(1)-AR as revealed by Western blotting and supported by binding analysis. Incubation of ventricular myocytes from Ovx rats with estrogen at 10(-9) M for 24 and 48 h, but not 12 h, significantly reduced lactate dehydrogenase release when the myocytes are subjected to simulated ischemia. The cardioprotective effect of 24 h estrogen incubation was accompanied by a reduction in the protein expression level of beta(1)-AR, which is estrogen receptor-dependent, whereas the lack of protection of 12-h estrogen incubation was not accompanied by any alterations in the expression level of beta(1)-AR. Together, the result from present study suggested that it is most likely that the cardioprotective effect of long-term estrogen replacement is due to suppressing the enhanced expression of cardiac beta(1)-AR in the Ovx rats, which in turn reduces cardiac injury when beta-AR is activated by sympathetic hyperactivity during ischemia. Therefore, suppression of the enhanced expression of cardiac beta(1)-AR in Ovx rats represents a novel cardioprotective mechanism of estrogen replacement therapy.     

Lipid-mediated delivery of brain-specific angiogenesis inhibitor 1 gene reduces corneal neovascularization in an in vivo rabbit model

Corneal neovascularization, which occurs in many pathologic states of the cornea, reduces the visual acuity. Recently, we found that the extracellular region of brain-specific angiogenesis inhibitor 1 (BAI1-ECR) has antiproliferative activity through functional blocking of alpha(v)beta(5) integrin in endothelial cells. In this study, we investigated the effects of lipid-mediated subconjunctival injection of the BAI1-ECR gene on corneal angiogenesis induced by epithelial debridement by heptanol in the rabbit. When a pEGFP-BAI1-ECR plasmid was given subconjunctivally 1 week after epithelial debridement, green fluorescence was detected in the corneal stroma with expression persisting for 7 days. To test the effect of BAI1-ECR on neovascularization, rabbits were injected with the BAI1-ECR gene or empty vector two or three times at 1-week intervals beginning 1 week after debridement. When measured with biomicroscopy at 1 or 2 weeks after two weekly injections, BAI1-delivered eyes had significantly less neovascularized corneal area than vector-injected ones in both time periods. Similar microscopic results were obtained after three weekly injections of BAI1-ECR. In quantitative histological examination, the BAI1-receiving eyes showed significantly less neovascular area and number of vessels than vector-injected ones. Also, after two weekly injections, BAI1-delivered eyes had decreased neovascularized corneal area equivalent to that of anti-VEGF antibody-injected ones. These results indicate that BAI1-ECR gene delivery effectively reduces experimental corneal neovascularization and suggest that the BAI1-ECR protein can be used as an angiogenesis suppressor in the eye.     

The novel melphalan prodrug J1 inhibits neuroblastoma growth in vitro and in vivo

Neuroblastoma is the most common extracranial solid tumor of childhood. The activity of J1 (l-melphalanyl-p-l-fluorophenylalanine ethyl ester), an enzymatically activated melphalan prodrug, was evaluated in neuroblastoma models in vitro and in vivo. Seven neuroblastoma cell lines with various levels of drug resistance were screened for cytotoxicity of J1 alone or in combination with standard cytotoxic drugs, using a fluorometric cytotoxicity assay. J1 displayed high cytotoxic activity in vitro against all neuroblastoma cell lines, with IC(50) values in the submicromolar range, significantly more potent than melphalan. The cytotoxicity of J1, but not melphalan, could be significantly inhibited by the aminopeptidase inhibitor bestatin. J1 induced caspase-3 cleavage and apoptotic morphology, had additive effects in combination with doxorubicin, cyclophosphamide, carboplatin, and vincristine, and synergistically killed otherwise drug-resistant cells when combined with etoposide. Athymic rats and mice carrying neuroblastoma xenografts [SH-SY5Y, SK-N-BE(2)] were treated with equimolar doses of melphalan, J1, or no drug, and effects on tumor growth and tissue morphology were analyzed. Tumor growth in vivo was significantly inhibited by J1 compared with untreated controls. Compared with melphalan, J1 more effectively inhibited the growth of mice with SH-SY5Y xenografts, was associated with higher caspase-3 activation, fewer proliferating tumor cells, and significantly decreased mean vascular density. In conclusion, the melphalan prodrug J1 is highly active in models of neuroblastoma in vitro and in vivo, encouraging further clinical development in this patient group.     

The novel oral Hsp90 inhibitor NVP-HSP990 exhibits potent and broad-spectrum antitumor activities in vitro and in vivo

A novel oral Hsp90 inhibitor, NVP-HSP990, has been developed and characterized in vitro and in vivo. In vitro, NVP-HSP990 exhibits single digit nanomolar IC(50) values on three of the Hsp90 isoforms (Hsp90α, Hsp90β, and GRP94) and 320 nanomolar IC(50) value on the fourth (TRAP-1), with selectivity against unrelated enzymes, receptors, and kinases. In c-Met amplified GTL-16 gastric tumor cells, NVP-HSP990 dissociated the Hsp90-p23 complex, depleted client protein c-Met, and induced Hsp70. NVP-HSP990 potently inhibited the growth of human cell lines and primary patient samples from a variety of tumor types. In vivo, NVP-HSP990 exhibits drug-like pharmaceutical and pharmacologic properties with high oral bioavailability. In the GTL-16 xenograft model, a single oral administration of 15 mg/kg of NVP-HSP990 induced sustained downregulation of c-Met and upregulation of Hsp70. In repeat dosing studies, NVP-HSP990 treatment resulted in tumor growth inhibition of GTL-16 and other human tumor xenograft models driven by well-defined oncogenic Hsp90 client proteins. On the basis of its pharmacologic profile and broad-spectrum antitumor activities, clinical trials have been initiated to evaluate NVP-HSP990 in advanced solid tumors.     

caspase抑制剂对缺氧诱导的心肌细胞凋亡影响的实验研究

目的 探讨caspase抑制剂对缺氧诱导的培养乳鼠心肌细胞凋亡的作用。方法 将SD乳鼠的培养心肌细胞随机分为3组:对照组、缺氧72 h(I72 h)组,以及caspasee抑制剂组。应用TUNEL法及流式细胞仪分析心肌细胞凋亡的变化;借助caspase-3荧光分析试剂盒,荧光比色法检测心肌细胞凋亡过程中caspase-3活性的变化。结果 caspase抑制剂组凋亡指数(AI值)和细胞凋亡百分率分别为:(14.10±2.56)％,(14.93±2.47)％,与I72 h组(46.49±4.93)％、(48.43±4.18)％相比明显降低(P<0.01)。caspase-3活性检测显示:caspase抑制剂组的caspase-3活性比缺氧72 h组降低了52.85％(P<0.01)。结论caspase抑制剂能明显抑制缺氧诱导的心肌细胞凋亡,其作用机制与抑制caspase-3蛋白酶活性密切相关。