Chunjing Wu

Arginine deprivation as a targeted therapy for cancer.

Certain cancers may be auxotrophic for a particular amino acid, and amino acid deprivation is one method to treat these tumors. Arginine deprivation is a novel approach to target tumors which lack argininosuccinate synthetase (ASS) expression. ASS is a key enzyme which converts citrulline to arginine. Tumors which usually do not express ASS include melanoma, hepatocellular carcinoma, some mesotheliomas and some renal cell cancers. Arginine can be degraded by several enzymes including arginine deiminase (ADI). Although ADI is a microbial enzyme from mycoplasma, it has high affinity to arginine and catalyzes arginine to citrulline and ammonia. Citrulline can be recycled back to arginine in normal cells which express ASS, whereas ASS(-) tumor cells cannot. A pegylated form of ADI (ADI-PEG20) has been formulated and has shown in vitro and in vivo activity against melanoma and hepatocellular carcinoma. ADI-PEG20 induces apoptosis in melanoma cell lines. However, arginine deprivation can also induce ASS expression in certain melanoma cell lines which can lead to in vitro drug resistance. Phase I and II clinical trials with ADI-PEG20 have been conducted in patients with melanoma and hepatocellular carcinoma, and antitumor activity has been demonstrated in both cancers. This article reviews our laboratory and clinical experience as well as that from others with ADI-PEG20 as an antineoplastic agent. Future direction in utilizing this agent is also discussed.

Overcoming cisplatin resistance by mTOR inhibitor in lung cancer

BackgroundCisplatin resistance is complex and involves several different mechanisms. Employing cDNA microarray analysis, we have found that cisplatin resistant cells share the common characteristic of increase in ribosomal proteins and elongation factors. We hypothesize that in order to survive cisplatin treatment, cells have to synthesize DNA repair proteins, antiapoptotic proteins and growth-stimulating proteins. Thus, by blocking the translation of these proteins, one should be able to restore cisplatin sensitivity. We have studied the role of CCI-779, an ester analog of rapamycin which is known to inhibit translation by disabling mTOR, in restoring cisplatin sensitivity in a panel of cisplatin resistant cell lines. We have also determined the role of CCI-779 in P-gp1 and MRP1 mediated resistance.ResultsOur data show that CCI-779 possess antiproliferative effects in both cisplatin sensitive and resistant cell lines, but shows no effect in P-gp1 and MRP1 overexpressing cell lines. Importantly, CCI-779 at 10 ng/ml (less that 10% of the growth inhibitory effect) can increase the growth inhibition of cisplatin by 2.5–6 fold. Moreover, CCI-779 also enhances the apoptotic effect of cisplatin in cisplatin resistant cell lines. In these resistant cells, adding CCI-779 decreases the amount of 4E-BP phosphorylation and p-70S6 kinase phosphorylation as well as lower the amount of elongation factor while cisplatin alone has no effect. However, CCI-779 can only reverse P-gp mediated drug resistance at a higher dose(1 ug/ml).ConclusionWe conclude that CCI-779 is able to restore cisplatin sensitivity in small cell lung cancer cell lines selected for cisplatin resistance as well as cell lines derived from patients who failed cisplatin. These findings can be further explored for future clinical use. On the other hand, CCI-779 at achievable clinical concentration, has no growth inhibitory effect in P-gp1 or MRP1 overexpressing cells. Furthermore, CCI-779 also appears to be a weak MDR1 reversal agent. Thus, it is not a candidate to use in MDR1 or MRP1 overexpressing cells.

Arginine Deprivation, Autophagy, Apoptosis (AAA) for the Treatment of Melanoma

The majority of melanoma cells do not express argininosuccinate synthetase (ASS), and hence cannot synthesize arginine from citrulline. Their growth and proliferation depend on exogenous supply of arginine. Arginine degradation using arginine deiminase (ADI) leads to growth inhibition and eventually cell death while normal cell which express ASS can survive. This notion has been translated into clinical trial. Pegylated ADI (ADI-PEG20) has shown antitumor activity in melanoma. However, the sensitivity to ADI is different among ASS(-) melanoma cells. We have investigated and reviewed the signaling pathways which are affected by arginine deprivation and their consequences which lead to cell death. We have found that arginine deprivation inhibits mTOR signaling but leads to activation of MEK and ERK with no changes in BRAF. These changes most likely lead to autophagy, a possible mechanism to survive by recycling intracellular arginine. However apoptosis does occur which can be both caspase dependent or independent In order to increase the therapeutic efficacy of this form of treatment, one should consider adding other agent(s) which can drive the cells toward apoptosis or inhibit the autophagic process.

Inhibition of mTOR restores cisplatin sensitivity through down-regulation of growth and anti-apoptotic proteins.

We show that cisplatin resistance in certain lung cancer cell lines can be reversed through inhibition of mTOR (mammalian Target of Rapamycin). These cell lines appear to possess high levels of phospho-mTOR, phospho-AKT and other growth-related proteins, such as hTERT (human telomerase reverse transcriptase), and Cyclin D3 which decrease upon inhibition of mTOR. Interestingly in one cisplatin resistant cell line which expresses BCL2/BCLxL, treatment with mTOR inhibitor (CCI-779) results in decreased levels of these anti-apoptotic proteins and may contribute to increasing apoptosis. Moreover, continuous exposure to CCI-779 was found to increase the expression of the multi-drug resistant P-gp1(P-gycoprotein1) efflux pump and therefore should be taken into consideration when designing clinical trials with this compound.

TRAIL induces autophagic protein cleavage through caspase activation in melanoma cell lines under arginine deprivation

Arginine deprivation is a promising strategy for treating ASS-negative malignant tumors including melanoma. However, autophagy can potentially counteract the effectiveness of this treatment by acting as a pro-survival pathway. By combining tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) with arginine deprivation using ADI-PEG20 (pegylated arginine deiminase), we achieved enhanced apoptosis and accelerated cell death in melanoma cell lines. This implies a switch from autophagy to apoptosis. In our current investigation, we found that TRAIL could induce the cleavage of two key autophagic proteins, Beclin-1 and Atg5, in the combination treatment. Using specific inhibitors for individual caspases, we found that caspase-8 inhibitor could completely abolish the cleavage. Furthermore, caspase-8 inhibitor was able to fully reverse the enhanced cytotoxicity induced by TRAIL. Inhibitors for caspase-3, 6, 9, and 10 were able to block the cleavage of these two autophagic proteins to some extent and correspondingly rescue cells from the cytotoxicity of the combination of TRAIL and arginine deprivation. In contrast, calpain inhibitor could not prevent the cleavage of either Beclin-1 or Atg5, and was unable to prevent cell death. Overall, our data indicate that the cleavage of Beclin-1 and Atg5 by TRAIL-initiated caspase activation is one of the mechanisms that lead to the enhancement of the cytotoxicity in the combination treatment.

The Relationship of Thioredoxin-1 and Cisplatin Resistance: Its Impact on ROS and Oxidative Metabolism in Lung Cancer Cells

Elimination of cisplatin-resistant lung cancer cells remains a major obstacle. We have shown that cisplatin-resistant tumors have higher reactive oxygen species (ROS) levels and can be exploited for targeted therapy. Here, we show that increased secretion of the antioxidant thioredoxin-1 (TRX1) resulted in lowered intracellular TRX1 and contributed to higher ROS in cisplatin-resistant tumors in vivo and in vitro. By reconstituting TRX1 protein in cisplatin-resistant cells, we increased sensitivity to cisplatin but decreased sensitivity to elesclomol (ROS inducer). Conversely, decreased TRX1 protein in parental cells reduced the sensitivity to cisplatin but increased sensitivity to elesclomol. Cisplatin-resistant cells had increased endogenous oxygen consumption and mitochondrial activity but decreased lactic acid production. They also exhibited higher levels of argininosuccinate synthetase (ASS) and fumarase mRNA, which contributed to oxidative metabolism (OXMET) when compared with parental cells. Restoring intracellular TRX1 protein in cisplatin-resistant cells resulted in lowering ASS and fumarase mRNAs, which in turn sensitized them to arginine deprivation. Interestingly, cisplatin-resistant cells also had significantly higher basal levels of acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS). Overexpressing TRX1 lowered ACC and FAS proteins expressions in cisplatin-resistant cells. Chemical inhibition and short interfering RNA of ACC resulted in significant cell death in cisplatin-resistant compared with parental cells. Conversely, TRX1 overexpressed cisplatin-resistant cells resisted 5-(tetradecyloxy)-2-furoic acid (TOFA)-induced death. Collectively, lowering TRX1 expression through increased secretion leads cisplatin-resistant cells to higher ROS production and increased dependency on OXMET. These changes raise an intriguing therapeutic potential for future therapy in cisplatin-resistant lung cancer. Mol Cancer Ther; 11(3); 604–15. ©2012 AACR.

The combination of ADI-PEG20 and TRAIL effectively increases cell death in melanoma cell lines

Current treatment for advanced, metastatic melanoma is not very effective, and new modalities are needed. ADI-PEG20 is a drug that specifically targets ASS-negative malignant melanomas while sparing the ASS-expressing normal cells. Although laboratory research and clinical trials showed promising results, there are some ASS-negative cell lines and patients that can develop resistance to this drug. In this report, we combined ADI-PEG20 with another antitumor drug TRAIL to increase the killing of malignant melanoma cells. This combination can greatly inhibit cell growth (to over 80%) and also enhanced cell death (to over 60%) in four melanoma cell lines tested compared with control. We found that ADI-PEG20 could increase the cell surface receptors DR4/5 for TRAIL and that caspase activity correlated with the increased cell death. These two drugs could also increase the level of Noxa while decrease that of survivin. We propose that these two drugs can complement each other by activating the intrinsic and extrinsic apoptosis pathways, thus enhance the killing of melanoma cells.

Redox regulation of matrix metalloproteinase gene family in small cell lung cancer cells

It has been implicated that reactive oxygen species (ROS) play important roles in modulating tumor progression. However, the mechanisms by which redox-regulated tumor progression are largely unknown. We previously demonstrated that reduced intracellular redox conditions could be achieved in stably transfected small cell lung cancer cells with γ-glutamylcysteine synthetase (γ-GCSh) cDNA which encodes a rate-limiting enzyme in the biosynthesis of glutathione (GSH), a major physiological redox regulator. In the present study, using DNA microarray analyses, we compared the expression profiles between the γ-GCSh-transfected cells and their nontransfected counterpart. We observed downregulation of several matrix metalloproteinases (MMPs), i.e., MMP1 and MMP3, and MMP10 in the transfected cells. Dot blot and Northern blot hybridizations confirmed that, among the 18 MMP gene family members and four tissue inhibitors of matrix metalloprotein family (TIMP) analyzed, the expression levels of these three MMPs were consistently reduced. Transiently increased γ-GCSh expression using tetracycline-inducible γ-GCSh adenoviral expression system also showed down-regulation of MMP3 and MMP10, but not MMP1. Our results demonstrated that redox regulation of MMP1, MMP3 and MMP10 expression depend upon different modes of redox manipulation. These results bear implication that antioxidant modulation of antitumor progression may be contributed at least in part by the downregulation of a subset of metrix metalloproteins.

The Relationship of Arginine Deprivation, Argininosuccinate Synthetase and Cell Death in Melanoma

Trypanosomiasis and leishmaniasis are two debilitating disease groups caused by parasites of Trypanosoma and Leishmania spp. and affecting millions of people worldwide. A brief outline of the potential targets for rational drug design against these diseases are presented, with an emphasis placed on the enzyme trypanothione reductase. Trypanothione reductase was identified as unique to parasites and proposed to be an effective target against trypanosomiasis and leishmaniasis. The biochemical basis of selecting this enzyme as a target, with reference to the simile and contrast to human analogous enzyme glutathione reductase, and the structural aspects of its active site are presented. The process of designing selective inhibitors for the enzyme trypanothione reductase has been discussed. An overview of the different chemical classes of inhibitors of trypanothione reductase with their inhibitory activities against the parasites and their prospects as future chemotherapeutic agents are briefly revealed.Background and Aim Both thalassemia and carnitine deficiency represent independent causes of erythropoietin resistance, and thus anemia, in uremic patients. We evaluated the unknown long-term effects of L-carnitine administration in β-thalassemic on chronic hemodialysis. Methods We studied twelve subjects (M = 8; F = 4) affected by β-thalassemia minor (β-thal; HbA2 level = 6.6 ± 0.6%) and forty non-thalassemic subjects (M = 24; F = 16) as controls (C), on chronic hemodialysis treatment. Patients and controls were at target hemoglobin levels (11–12g/dl) prior to the study and underwent to i.v. L-carnitine administration for a one year period-time. Results Groups were comparable for age, gender, serum levels of hemoglobin (Hb), iron, ferritine, PTH and aluminum, transferrin saturation, and dialysis modalities. During the study both groups showed significant Hb increase and erythropoietin (EPO) decrease; as a difference, such changes emerged at the 3rd month in C but at the 8th month in β-thal. At start, during the dialysis session the erythrocyte MCV reduced in C but not in β-thal (65.3 ± 3.2 to 65.5 ± 3.2 fl; NS); along carnitine administration period, however, MCV during dialysis decreased also in β-thal, starting since the 9th month of treatment. Conclusion This study provides evidence of the lowering of EPO resistance in β-thalassemia patients on hemodialysis due to long-term carnitine administration. Thus, prolonged carnitine supplementation should be suggested to patients on dialysis affected by β-thalassemia with poorly responsive anemia, or requiring large doses of erythropoietin.The effect of cinnarizine, a drug used for the treatment of vertigo was assessed in animal models of visceral nociception, inflammation and gastric mucosal injury. Cinnarizine (1.25–20 mg/kg, s.c.) caused dose-dependent inhibition of the abdominal constrictions evoked by i.p. injection of acetic acid by 38.7–99.4%. This effect of cinnarizine (2.5 mg/kg) was unaffected by co-administration of the centrally acting dopamine D2 receptor antagonists, sulpiride, haloperidol or metoclopramide, the peripherally acting D2 receptor antagonist domperidone, but increased by the D2 receptor agonist bromocryptine and by the non-selective dopamine receptor antagonist chlorpromazine. The antinociception caused by cinnarizine was naloxone insenstive, but enhanced by propranolol, atropine and by yohimbine. The antinociceptive effect of cinnarizine was prevented by co-treatment with the adenosine receptor blocker theophylline or by the ATP-sensitive potassium channel (KATP) blocker glibenclamide. Cinnarizine at 2.5 mg/kg reversed the baclofen-induced antinociception. Cinnarizine at 2.5 mg/kg reduced immobility time in the Porsolt’s forced-swimming test by 24%. Cinnarizine inhibited the paw oedema response to carrageenan and reduced gastric mucosal lesions caused by indomethacin in rats. It is suggested that cinnarizine exerts anti-inflammatory, antinociceptive and gastric protective properties. The mechanism by which cinnarizine modulates pain transmission is likely to involve adenosine receptors and KATP channels.Brain tumor is associated with poor prognosis. The treatment option is severely limited for a patient with brain tumor, despite great advances in understanding the etiology and molecular biology of brain tumors that have lead to breakthroughs in developing pharmaceutical strategies, and ongoing NCI/Pharma-sponsored clinical trials. We reviewed the literature on molecular targeted agents in preclinical and clinical studies in brain tumor for the past decade, and observed that the molecular targeting in brain tumors is complex. This is because no single gene or protein can be affected by single molecular agent, requiring the use of combination molecular therapy with cytotoxic agents. In this review, we briefly discuss the potential molecular targets, and the challenges of targeted brain tumor treatment. For example, glial tumors are associated with over-expression of calcium-dependent potassium (KCa) channels, and high grade glioma express specific KCa channel gene (gBK) splice variants, and mutant epidermal growth factor receptors (EGFRvIII). These specific genes are promising targets for molecular targeted treatment in brain tumors. In addition, drugs like Avastin and Gleevec target the molecular targets such as vascular endothelial cell growth factor receptor, platelet-derived growth factor receptors, and BRC-ABL/Akt. Recent discovery of non-coding RNA, specifically microRNAs could be used as potential targeted drugs. Finally, we discuss the role of anti-cancer drug delivery to brain tumors by breaching the blood-brain tumor barrier. This non-invasive strategy is particularly useful as novel molecules and humanized monoclonal antibodies that target receptor tyrosine kinase receptors are rapidly being developed.The notorious biotechnological advance of the last few decades has allowed the development of experimental methods for understanding molecular mechanisms of genes and new therapeutic approaches. Gene therapy is maturing into a viable, practical method with the potential to cure a variety of human illnesses. Some nucleic-acid-based drugs are now available for controlling the progression of genetic diseases by inhibiting gene expression or the activity of their gene products. New therapeutic strategies employ a wide range of molecular tools such as bacterial plasmids containing transgenic inserts, RNA interference and aptamers. A nucleic-acid based constitution confers a lower immunogenic potential and as result of the high stringency selection of large molecular variety, these drugs have high affinity and selectivity for their targets. However, nucleic acids have poor biostability thus requiring chemical modifications and delivery systems to maintain their activity and ease their cellular internalization. This review discusses some of the mechanisms of action and the application of therapies based on nucleic acids such as aptamers and RNA interference as well as platforms for cellular uptake and intracellular delivery of therapeutic oligonucleotides and their trade-offs.Background Phospholipases A2 (PLA2) are aggressive enzymes that can destroy phospholipids of cell membranes. The resulting cell fragments trigger the kallikrein—mediated contact phase of coagulation. The aim of the present study was to expose citrated whole blood to PLA2 and to quantify thrombin generation in recalcified plasma. Methods Normal citrated blood was exposed to bovine pancreatic or snake PLA2, lipopolysaccharide (LPS), or zymosan A for 30–45 min (RT). After centrifugation the plasma samples were recalcified (10 + 1) with 250 mM CaCl2 in the recalcified coagulation activity assay (RECA). After 0–45 min coagulation reaction time (CRT at 37°C) 1.6 M arginine (final test concentration) was added to stop hemostasis activation and to depolymerize non-crosslinked fibrin. The generated thrombin activity was chromogenically determined. Results 100 ng/ml bovine pancreatic or snake PLA2 generates about 0.2–0.8 IU/ml thrombin after 15 min CRT. This thrombin generation is similar as that induced by 200 ng/ml LPS or 20 μg/ml zymosan A. Up to 60 ng/ml bovine pancreatic PLA2 the generated thrombin activity is proportional to the PLA2 activity used; 1 μg/ml PLA2 induces much less thrombin, but PLA2 at 10 μg/ml again results into thrombin generation of 0.1–3 IU/ml at 10–15 min CRT. As control, in pooled normal citrated plasma there is no significant change in thrombin generation when exposed to up to 10 μg/ml bovine pancreatic PLA2. Discussion Elevated plasmatic PLA2 activities (occurring e.g. in trauma, pancreatitis, or sepsis) activate the blood hemostasis system resulting in pathologic disseminated intravascular coagulation (PDIC). It is suggested to diagnose these life threatening states as early as possible, screening all patients for plasmatic thrombin activity.The targets for licensed drugs used for the treatment of human immunodeficiency virus type 1 (HIV-1) are confined to the viral reverse transcriptase (RT), protease (PR), and the gp41 transmembrane protein (TM). While currently approved drugs are effective in controlling HIV-1 infections, new drug targets and agents are needed due to the eventual emergence of drug resistant strains and drug toxicity. Our increased understanding of the virus life-cycle and how the virus interacts with the host cell has unveiled novel mechanisms for blocking HIV-1 replication. This review focuses on inhibitors that target the late stages of virus replication including the synthesis and trafficking of the viral polyproteins, viral assembly, maturation and budding. Novel approaches to blocking the oligomerization of viral enzymes and the interactions between viral proteins and host cell factors, including their feasibility as drug targets, are discussed.Sinomenine is one of the alkaloids extracted from Chinese medical plant, Sinomenium acutum Rehder et Wilson. Sinomenine has been used for Rheumatoid arthritis as an anti-inflammatory and immunomodulative drugs. We have so far been investigated the cardiovascular pharmacological actions of sinomenine. Sinomenine dilated NE (5 μM)-, KCl (60 mM)- and PDB (300 nM)-induced vasoconstrictions. The pretreatment with nicardipine (0.1 μM), staurosporine (30 nM), L-NMMA (100 μM), indomethacin (10 μM) or propranolol significantly attenuated the sinomenine-induced vasorelaxation. Therefore, these results indicate that sinomenine causes the vasorelaxation by the involvement with the inhibitions of Ca2+ current (ICa) and PK-C, β-adrenoceptor stimulation, and the activation of NO and PGI2 syntheses in endothelium. On the other hand, in the ventricular cardiomyocytes of guinea pig, sinomenine inhibits ICa and simultaneously decreases the delayed rectifier K+ current (IK), resulting in the prolongation of action potential duration. Sinomenine also suppresses the dysrhysmias induced by triggered activities under the Ca2+ overload condition. Therefore, sinomenine may be expected as one of effective therapeutic drugs for heart failure and dysrhythmias, and may maintain the cardiovascular functions due to modulation of cardiac ionic channels and blood vessels.Background The contact phase of coagulation is of physiologic/pathophysiologic importance, whenever unphysiologic polynegative substances such as cell fragments (microparticles) get in contact with blood. There are several clinically used inhibitors of intrinsic thrombin generation. Here the inhibitory concentrations 50% (IC50) of these anticoagulants are measured by the highly specific thrombin generation assay INCA. Methods Unfrozen pooled normal citrated plasma in polystyrole tubes was supplemented at 23°C in duplicate with 0–2 IU/ml low molecular weight heparin (dalteparin), 0–2 IU/ml unfractionated heparin, 0–500 KIU/ml aprotinin, or 0–40 mM arginine. 50 μl plasma or 1 IU/ml thrombin standard were pipetted into a polystyrole microtiter plate with flat bottom. 5 μl SiO2/CaCl2 - reagent (INCA activator) were added and after 0–30 min incubation at 37°C 100 μl 2.5 M arginine, pH 8.6, were added; arginine inhibits hemostasis activation and depolymerizes generated fibrin within 20 min at 23°C. The in the physiologic 37°C incubation phase generated thrombin was then chromogenically detected. The intra-assay CV values were < 5%. Results and Discussion The approximate IC50 were 0.01 IU/ml dalteparin, 0.02 IU/ml heparin, 25 KIU/ml aprotinin, and 12 mM arginine. The efficiency of any anticoagulant on intrinsic thrombin generation should be measured for each individual patient.Bone morphogenetic protein (BMP) appears to be one of the most promising cytokine and for clinical use in reconstructive surgery for bony defects and augmentation. To evaluate the effect of basic fibroblast growth factor (bFGF), FK506, elcatonin, and hyperbaric oxygenation (HBO) on osteoinduction by recombinant human bone morphogenetic protein-2 (rhBMP-2), 2 or 5 μg of rhBMP-2 was implanted into intramuscular sites of rats. At 21 days after implantation, the osteoinductive activity in the treatment group and control group was compared radiographically, biochemically, and histologically. The amount of new bone in the treatment group was significantly greater than that in the control group. The alkaline phosphatase activity and calcium content in the treatment group were significantly higher than those in the control group. These results suggest that bFGF, FK506, elcatonin, and HBO accelerated the activity and rate of osteoinduction by rhBMP2. These results may be useful when BMP is applied clinically in near future.Aromatic diamidines have been successfully used to combat a wide range of parasites that cause important human infections. Recently we reported that a N-phenyl-substituted analogue of furamidine (DB569) exerts a micromolar trypanocidal activity against Trypanosoma cruzi in vitro. Since DB569 also reduces the cardiac parasitism and increases the survival rates of T. cruzi-infected mice, our present aim was to analyze the potential protection of DB569 in the development of altered cardiac electrical conduction system during acute and chronic T. cruzi infection. In our experimental model of acute infection (Swiss mice inoculated with Y strain of T. cruzi), the prevailing disorder observed in electrocardiogram (ECG) analyses was sinus bradycardia. This ECG alteration was reverted in acutely infected mice treated with DB569. Interestingly, the DB569 treatment reduced significantly the numbers of CD8+ T cells in the cardiac infiltration. In addition, the noticed protection of DB569 in the ECG findings of acutely-infected animals was further extended to the chronic infection. Our data suggest that the reversion to and further maintenance of normal ECG profile in the DB569-treated infected animals may be associated with the reduced cardiac CD8+ lymphocyte infiltration and parasitism that might be ultimately contributing to their increased survival rates.Methamphetamine (METH) abuse is a serious health and social problem worldwide. At present, however, there are no effective medications for the treatment of METH abuse. Of the intracellular METH target proteins, monoamine oxidase (MAO) is involved in the regulation of monoaminergic tone in the brain, resulting in the modulation of METH-induced behavioral abnormalities in mammals. The METH-induced expression of increased motor activity, stereotypy, and sensitization is closely associated with monoaminergic transmission in the brain. Modification of MAO activity by MAO inhibitors can influence METH action. Of the MAO inhibitors, the propargylamine derivative clorgyline, an irreversible MAO-A inhibitor, effectively blocks METH-induced hyperlocomotion and behavioral sensitization in rodents. Analysis of the associated monoaminergic activity indicates an involvement of altered striatal serotonergic transmission as well as an increased dopaminergic tone. Some effects of MAO inhibitors on METH action appear to be independent of MAO, suggesting complex mechanisms of action of MAO inhibitors in METH abuse. This review describes current research to find effective treatment for METH abuse, using MAO inhibitors.Objective Anthroposophic medications (AMED) are widely used, but safety data on AMED from large prospective studies are sparse. The objective of this analysis was to determine the frequency of adverse drug reactions (ADR) to AMED in outpatients using AMED for acute respiratory and ear infections. Methods A prospective four-week observational cohort study was conducted in 21 primary care practices in Europe and the U.S.A. The cohort comprised 715 consecutive outpatients aged ≥1 month, treated by anthroposophic physicians for acute otitis and respiratory infections. Physicians’ prescription data and patient reports of adverse events were analyzed. Main outcome measures were use of AMED and ADR to AMED. Results Two patients had confirmed ADR to AMED: 1) swelling and redness at the injection site after subcutaneous injections of Prunus spinosa 5%, 2) sleeplessness after intake of Pneumodoron® 2 liquid. These ADR lasted one and two days respectively; both subsided after dose reduction; none were unexpected; none were serious. The frequency of confirmed ADR to AMED was 0.61% (2/327) of all different AMED used, 0.28% (2/715) of patients, and 0.004% (3/73,443) of applications. Conclusion In this prospective study, anthroposophic medications used by primary care patients with acute respiratory or ear infections were well tolerated.Cyclophilin (CyP) is a peptidyl prolyl cis/trans isomerase, catalyzing the cis-trans isomerization of proline residues in proteins. CyP plays key roles in several different aspects of cellular physiology including the immune response, transcription, mitochondrial function, cell death, and chemotaxis. In addition to these cellular events, a number of reports demonstrated that CyP plays a critical role in the life cycle of viruses, especially human immunodeficiency virus (HIV) and hepatitis C virus (HCV). These two viruses are significant causes of morbidity and mortality worldwide, but current therapies are often insufficient. CyP may provide a novel therapeutic target for the management and/or cure of these diseases, in particular HCV.Anti-angiogenic therapy is emerging as a valuable tool in the treatment of patients with cancer. As VEGF is a central target in anti-angiogenic therapy, its levels in the circulation might be relevant in selecting tumor types or patients likely to respond to this treatment. Additional VEGF has been recognized as a key factor in the pathogenesis of diabetic retinopathy. Recently anti-angiogenic therapy has been advocated in this situation. We measured VEGF levels in whole blood in 42 patients with high grade (n = 26) and low grade (n = 16) end stage cancer, and in 28 healthy controls and 37 patients with diabetes related vascular disease. Only 2/26 patients in the group of high grade cancer had significantly elevated VEGF levels, 1/16 in the low grade group and 1/28 in the healthy control group. In contrast, in 10/37 diabetic patients the mean VEGF levels were significantly elevated compared to the other groups. The mean level in these diabetic patients was significantly elevated compared to the other groups. These data indicate the limitation of the use of circulating VEGF levels as a potential selection criterion for anti-angiogenic therapy in cancer patients and suggest further studies into its application in the management of diabetic complications.Endothelial dysfunction is a pathological entity that multiply affects the health status. Erectile dysfunction is being recognized as a condition that is strongly interrelated with endothelial dysfunction, being a vascular event itself. Oral pharmacotherapy for erectile dysfunction has provided us with a new armamentarium on this condition. Phosphodiesterase 5 inhibitors have been investigated and proved useful in clinical practice for erectile dysfunction but in addition to this, the results seem promising of a beneficial effect on endothelial dysfunction, as well.The effect of the antiviral agent ribavirin given alone or in combination with silymarin on the development of liver injury induced in rats with carbon tetrachloride (CCl4; 2.8 ml/kg followed by 1.4 ml/kg after one week) was studied. Ribavirin at three dose levels (30, 60 or 90 mg/kg), silymarin (25 mg/kg) or combination of ribavirin (60 mg/kg) and silymarin (25 mg/kg) was administered once daily orally for 14 days, starting at time of administration of CCl4. The administration of ribavirin decreased the elevations in serum alanine aminotransferase (ALT) by 78.5, 82.1, 75.1%, aspartate aminotransferase (AST) 47.5, 37.4, 38.8%, and alkaline phosphatase (ALP) by 23.4, 16, 21.6%, respectively and also pre-vented the development of hepatic necrosis caused by CCl4. In comparison, the elevated serum ALT, AST and ALP levels decreased to 43.3%, 46%, and 37.5% of controls, respectively by silymarin. When silymarin was combined with ribavirin, the serum activities of AST and ALP were further decreased, indicating a beneficial additive effect. Morphometric analysis indicated significant reduction in the area of necrosis and fibrosis on ribavirin treatment and this was further reduced after the addition of silymarin. Metabolic pertuberations caused by CCl4 as reflected in a decrease in intracellular protein content in hepatocytes were improved by ribavirin monotherapy and to higher extent by combined silymarin and ribavirin therapy. Proliferating cell nuclear antigen was reduced in nuclei of hepatocytes by ribavirin montherapy or the combination of ribavirin and silymarin compared with CCl4-control group. The study demonstrates that ribavirin treatment in the model of CCl4-induced liver injury results in less liver damage. Results also indicate that the combined application of ribavirin and sily-marin is likely to be a useful additive in reducing liver injury.Although the oral route of drug administration is the most acceptable way of self-medication with a high degree of patient compliance, the intestinal absorption of many drugs is severely hampered by different biological barriers. These barriers comprise of biochemical and physical components. The biochemical barrier includes enzymatic degradation in the gastrointestinal lumen, brush border and in the cytoplasm of the epithelial cells as well as efflux transporters that pump drug molecules from inside the epithelial cell back to the gastrointestinal lumen. The physical barrier consists of the epithelial cell membranes, tight junctions and mucus layer. Different strategies have been applied to improve the absorption of drugs after oral administration, which range from chemical modification of drug molecules and formulation technologies to the targeting of receptors, transporters and specialized cells such as the gut-associated lymphoid tissues. This review focuses specifically on the targeting of receptor-mediated endocytosis, transporters and the absorption-site as methods of optimizing intestinal drug absorption. Intestinal epithelial cells express several nutrient transporters that can be targeted by modifying the drug molecule in such a way that it is recognized as a substrate. Receptor-mediated endocytosis is a transport mechanism that can be targeted for instance by linking a receptor substrate to the drug molecule of interest. Many formulation strategies exist for enhancing drug absorption of which one is to deliver drugs at a specific site in the gastrointestinal tract where optimum drug absorption takes place.It has been shown that melanoma cells do not express argininosuccinate synthetase (ASS) and therefore are unable to synthesize arginine from citrulline. Depleting arginine using pegylated arginine deiminase (ADI-PEG20) results in cell death in melanoma but not normal cells. This concept was translated into clinical trial and responses were seen. However, induction of ASS expression does occur which results in resistance to ADI-PEG20. We have used 4 melanoma cell lines to study factors which may govern ASS expression. Although these 4 melanoma cell lines do not express ASS protein or mRNA as detected by both immunoblot and northernblot analysis, ASS protein can be induced after these cells are grown in the presence of ADI-PEG20, but again repressed after replenishing arginine in the media. The levels of induction are different and one cell line could not be induced. Interestingly, a melanoma cell line with the highest level of induction could also be made resistant to ADI-PEG20. This resistant line possesses high levels of ASS mRNA and protein expression which cannot be repressed with arginine. Our study indicates that ASS expression in melanoma cells is complex and governed by biochemical parameters which are different among melanoma cells.The recent evidence that neurogenesis occurs throughout adulthood and neural stem cells (NSCs) reside in the adult central nervous system (CNS) suggests that the CNS has the potential for self-repair. Beside this potential, the function of newly generated neuronal cells in the adult brain remains the focus of intense research. The hippocampus of patients with depression show signs of atrophy and neuronal loss. This suggests that adult neurogenesis may contribute to the biology of depression. The observations that antidepressants, like fluoxetine, increase neurogenesis in the dentate gyrus (DG) and neurogenesis is required for the behavioral effect of antidepressants, lead to a new theory for depression and the design of new strategies and drugs for the treatment of depression. However, the role of adult neurogenesis in the etiology of depression remains the source of controversies and debates.Alzheimer’s disease (AD) is a neurodegenerative disease, characterized in the brain by amyloid plaque deposits and neurofibrillary tangles. It is the most common form of dementia among older people. There is at present no cure for AD, and current treatments consist mainly in drug therapy. Potential therapies for AD involve gene and cellular therapy. The recent confirmation that neurogenesis occurs in the adult brain and neural stem cells (NSCs) reside in the adult central nervous system (CNS) provide new opportunities for cellular therapy in the CNS, particularly for AD, and to better understand brain physiopathology. Hence, researchers have aimed at characterizing neurogenesis in patients with AD. Studies show that neurogenesis is increased in these patients, and in animal models of AD. The effect of drugs used to treat AD on neurogenesis is currently being investigated, to identify whether neurogenesis contributes to their therapeutic activities.Background For enhancement of drug effectiveness and reduction of drug toxicity, liposomal drugs have been studied in laboratories and clinics for decades. Although the results obtained from in vitro are encouraging, but the results from in vivo tests were not satisfactory. The main reasons for this situation were that we do not have enough information about the way how liposomal particles penetrating into solid tumor tissue, and what happening to the liposome particles after they got into the tumor tissue. In this paper, we are going to report the results from our observations on the way folic acid targeted and non-targeted PEGyl-DSPC liposomal doxorubicin particles penetrate into solid tumor tissue. Methods Subcutaneous transplanted murine L1210JF solid tumors in mice were used as a model. PEGyl liposomal doxorubicins were injected through tail venue, and tumor tissue samples were collected at special time points. Cryosections were cut and dried by a flowing of air after mounted on the slides right away. Then the dried cryosections were stained in water systems; the blood vessel cells were stained with green fluorescent FITC labeled antibody against CD31 antigen; the nuclei of the living cells were stained with a blue fluorescent dye DAPI. Since the whole procedure was carried out in aquatic system, the red color fluorescent liposomal doxorubicin particles remain visible under fluorescence microscope. Results Both folate conjugated and non-conjugated PEGyl-DSPC liposomal doxorubicin particles were only leaking out from the broken holes of blood vessels with a special direction and spread out for a limited distance, which was similar to the results showed before, in that observation a latex microsphere sample was used as a model.Some systemic rheumatic diseases and disorders, especially fibrotic and vascular disorders, are often refractory to corticosteroid therapy. Recently, ever accumulating evidence suggests that platelet-derived growth factor (PDGF) is involved in those refractory diseases. Imatinib mesylate inhibits the activation of PDGF receptor as well as c-Abl, Bcr-Abl and c-Kit tyrosine kinases. It has therefore been widely used for the treatment of chronic myeloid leukemia and gastrointestinal stromal tumors. Imatinib effectively suppresses the activation and proliferation of fibroblasts, mesangial cells and smooth muscle cells both in vitro and in vivo. Additionally, it has recently been reported that some patients with rheumatoid arthritis or idiopathic pulmonary arterial hypertension demonstrated a good clinical response to imatinib therapy. Imatinib may therefore overcome the limitations of current therapeutic strategy with corticosteroids and immunosuppressive agents for refractory diseases, such as systemic sclerosis and interstitial lung diseases, without clinical intolerability.Our understanding of the physiology of digestion, absorption, secretion, and motility in the gastrointestinal tract has improved immensely. Today it is well established that the gross functions of the gastrointestinal tract depend on the coordination between the muscles, nerves and hormones. The enteric nervous system (ENS) is involved in most of the physiological and pathophysiological processes in the gastrointestinal tract. Therefore, clinical and experimental studies on the ENS provide the basis for a better understanding of the mechanisms involved in gastrointestinal disorders and promote the development of therapeutic options. This review outlines some of the current views on the role of the ENS and its related hormones in gastrointestinal motility.

N' 1 ,N' 3 -Dimethyl-N' 1 ,N' 3 -bis(phenylcarbonothioyl) Propanedihydrazide (Elesclomol) Selectively Kills Cisplatin Resistant Lung Cancer Cells through Reactive Oxygen Species (ROS)

Cisplatin is an important chemotherapeutic agent in lung cancer treatment. The mechanism of drug resistance to cisplatin is complex and historically has been difficult to overcome. We report here that cisplatin resistant lung cancer cell lines possess high basal levels of reactive oxygen species (ROS) when compared to normal cells and their parental cell counterparts. These resistant cells also have low thioredoxin (TRX) levels which may be one of the contributory factors to high ROS. N′1,N′3-dimethyl-N′1,N′3-bis(phenylcarbonothioyl) propanedihydrazide (elesclomol), an agent known to increase ROS is selectively toxic to cisplatin-resistant cells, while sparing normal cells and the parental counterpart. The cytotoxic effect of elesclomol in resistant cells is accompanied by further decreases in TRX and glutathione (GSH) antioxidant systems, while opposite results were found in parental cells. The ID50 of elesclomol in cisplatin-resistant cells ranged from 5–10 nM, which is well within clinically achievable ranges. N-Acetylcysteine (NAC), which is known to neutralize ROS, can abolish the cytotoxic effect of elesclomol, suggesting that the cytotoxic effect results from increased ROS. Overall, our data suggest that elesclomol selectively kills cisplatin-resistant tumor cells through increased ROS. This agent may hold potential to overcome cisplatin resistance and should be further explored to treat patients who have failed cisplatin therapy.