Quinacrine inhibits HIF-1α/VEGF-A mediated angiogenesis by disrupting the interaction between cMET and ABCG2 in patient-derived breast cancer stem cells.

BACKGROUND: Breast cancer stem cells (BCSCs) have a critical role in progression of breast cancer by inducing angiogenesis. Several therapeutic strategies have been designed for the treatment of breast cancer by specifically preventing angiogenesis. But there is a dearth of study regarding the treatment procedure which can specifically target and kill the BCSCs and cause lesser harm to healthy cells of the body. A plant-based bioactive compound Quinacrine (QC) specifically kills cancer stem cells (CSCs) without harming healthy cells and also inhibits cancer angiogenesis but the detailed mechanistic study of its anti-CSCs and anti-angiogenic activity is yet to explore. HYPOTHESIS: Earlier report showed that both cMET and ABCG2 play an essential role in cancer angiogenesis. Both are present on the cell surface of CSCs and share an identical ATP-binding domain. Interestingly, QC a plant based and bioactive compound which was found to inhibit the function of CSCs marker cMET and ABCG2. These relevant evidence led us to hypothesize that cMET and ABCG2 may interact with each other and induce the production of angiogenic factors, resulting in activation of cancer angiogenesis and QC might disrupt the interaction between them to stop this phenomena. METHODS: Co-immunoprecipitation assay, immunofluorescence assay, and western blotting were performed by using ex vivo patient-derived breast cancer-stem-cells (PDBCSCs) and human umbilical vein endothelial cells (HUVECs). In silico study was carried out to check the interaction between cMET and ABCG2 in presence or absence of QC. Tube formation assay using HUVECs and in ovo Chorioallantoic membrane (CAM) assay using chick fertilized eggs were performed to monitor angiogenesis. In vivo patient-derived xenograft (PDX) mice model was used to validate in silico and ex vivo results. RESULTS: Data revealed that in a hypoxic tumor microenvironment (TME), cMET and ABCG2 interact with each other and upregulate HIF-1α/VEGF-A axis to induce breast cancer angiogenesis. In silico and ex vivo study showed that QC disrupted the interaction between cMET and ABCG2 to inhibit the angiogenic response in endothelial cells by reducing the secretion of VEGF-A from PDBCSCs within the TME. Knockdown of cMET, ABCG2 or both, significantly downregulated the expression of HIF-1α and reduced the secretion of pro-angiogenic factor VEGF-A in the TME of PDBCSCs. Additionally, when PDBCSCs were treated with QC, similar experimental results were obtained. CONCLUSION: In silico, in ovo, ex vivo and in vivo data confirmed that QC inhibited the HIF-1α/VEGF-A mediated angiogenesis in breast cancer by disrupting the interaction between cMET and ABCG2.

Comparison of chloroquine-like molecules for lysosomal inhibition and measurement of autophagic flux in the brain.

Measurement of autophagic flux in vivo is critical to understand how autophagy can be used to combat disease. Neurodegenerative diseases have a special relationship with autophagy, which makes measurement of autophagy in the brain a significant research priority. Currently, measurement of autophagic flux is possible through use of transgenic constructs, or application of a lysosomal inhibitor such as chloroquine. Unfortunately, chloroquine is not useful for measuring autophagic flux in the brain and the use of transgenic animals necessitates cross-breeding of transgenic strains and maintenance of lines, which is costly. To find a drug that could block lysosomal function in the brain for the measurement of autophagic flux, we selected compounds from the literature that appeared to have similar properties to chloroquine and tested their ability to inhibit autophagic flux in cell culture and in mice. These chemicals included chloroquine, quinacrine, mefloquine, promazine and trifluoperazine. As expected, chloroquine blocked lysosomal degradation of the autophagic protein LC3B-II in cell culture. Quinacrine also inhibited autophagic flux in cell culture. Other compounds tested were not effective. When injected into mice, chloroquine caused accumulation of LC3B-II in heart tissue, and quinacrine was effective at blocking LC3B-II degradation in male, but not female skeletal muscle. None of the compounds tested were useful for measuring autophagic flux in the brain. During this study we also noted that the vehicle DMSO powerfully up-regulated LC3B-II abundance in tissues. This study shows that chloroquine and quinacrine can both be used to measure autophagic flux in cells, and in some peripheral tissues. However, measurement of flux in the brain using lysosomal inhibitors remains an unresolved research challenge.

Identification of compounds inhibiting prion replication and toxicity by removing PrPC from the cell surface.

The vast majority of therapeutic approaches tested so far for prion diseases, transmissible neurodegenerative disorders of human and animals, tackled PrPSc , the aggregated and infectious isoform of the cellular prion protein (PrPC ), with largely unsuccessful results. Conversely, targeting PrPC expression, stability or cell surface localization are poorly explored strategies. We recently characterized the mode of action of chlorpromazine, an anti-psychotic drug known to inhibit prion replication and toxicity by inducing the re-localization of PrPC from the plasma membrane. Unfortunately, chlorpromazine possesses pharmacokinetic properties unsuitable for chronic use in vivo, namely low specificity and high toxicity. Here, we employed HEK293 cells stably expressing EGFP-PrP to carry out a semi-automated high content screening (HCS) of a chemical library directed at identifying non-cytotoxic molecules capable of specifically relocalizing PrPC from the plasma membrane as well as inhibiting prion replication in N2a cell cultures. We identified four candidate hits inducing a significant reduction in cell surface PrPC , one of which also inhibited prion propagation and toxicity in cell cultures in a strain-independent fashion. This study defines a new screening method and novel anti-prion compounds supporting the notion that removing PrPC from the cell surface could represent a viable therapeutic strategy for prion diseases.

Comprehensive Drug Testing of Patient-derived Conditionally Reprogrammed Cells from Castration-resistant Prostate Cancer.

BACKGROUND: Technology development to enable the culture of human prostate cancer (PCa) progenitor cells is required for the identification of new, potentially curative therapies for PCa. OBJECTIVE: We established and characterized patient-derived conditionally reprogrammed cells (CRCs) to assess their biological properties and to apply these to test the efficacies of drugs. DESIGN, SETTING, AND PARTICIPANTS: CRCs were established from seven patient samples with disease ranging from primary PCa to advanced castration-resistant PCa (CRPC). The CRCs were characterized by genomic, transcriptomic, protein expression, and drug profiling. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The phenotypic quantification of the CRCs was done based on immunostaining followed by image analysis with Advanced Cell Classifier using Random Forest supervised machine learning. Copy number aberrations (CNAs) were called from whole-exome sequencing and transcriptomics using in-house pipelines. Dose-response measurements were used to generate multiparameter drug sensitivity scores using R-statistical language. RESULTS AND LIMITATIONS: We generated six benign CRC cultures which all had an androgen receptor-negative, basal/transit-amplifying phenotype with few CNAs. In three-dimensional cell culture, these cells could re-express the androgen receptor. The CRCs from a CRPC patient (HUB.5) displayed multiple CNAs, many of which were shared with the parental tumor. We carried out high-throughput drug-response studies with 306 emerging and clinical cancer drugs. Using the benign CRCs as controls, we identified the Bcl-2 family inhibitor navitoclax as the most potent cancer-specific drug for the CRCs from a CRPC patient. Other drug efficacies included taxanes, mepacrine, and retinoids. CONCLUSIONS: Comprehensive cancer pharmacopeia-wide drug testing of CRCs from a CRPC patient highlighted both known and novel drug sensitivities in PCa, including navitoclax, which is currently being tested in clinical trials of CRPC. PATIENT SUMMARY: We describe an approach to generate patient-derived cancer cells from advanced prostate cancer and apply such cells to discover drugs that could be applied in clinical trials for castration-resistant prostate cancer.

ABT-888 and quinacrine induced apoptosis in metastatic breast cancer stem cells by inhibiting base excision repair via adenomatous polyposis coli.

PARP inhibitors in combination with other agents are in clinical trial against cancer, but its effect on cancer stem cells (CSCs) is limited. CSCs are responsible for drug resistance, metastasis and cancer relapse due to high DNA repair capacity. Here, we present preclinical effects of Quinacrine (QC) with ABT-888, a PARP inhibitor, on highly metastatic breast cancer stem cells (mBCSCs). An increased level of Adenomatous polyposis coli (APC) was noted after treatment with ABT-888 in QC pre-treated mBCSCs cells. Increased APC physically interacts with PARP-1 and inhibits PARylation causing the non assembly of base excision repair (BER) multiprotein complex, resulting in an irreparable DNA damage and subsequent apoptosis. Knockdown of APC in mBCSCs inhibited DNA damage, increased BER and PARylation, reduces apoptosis while the over-expression of APC in BT20 (APC low expressing) cells reversed the effect. Thus, combination of QC and ABT-888 decreased mBCSCs growth by activating APC and inhibiting BER within the cells.

Trypanothione reductase: a target protein for a combined in vitro and in silico screening approach.

With the goal to identify novel trypanothione reductase (TR) inhibitors, we performed a combination of in vitro and in silico screening approaches. Starting from a highly diverse compound set of 2,816 compounds, 21 novel TR inhibiting compounds could be identified in the initial in vitro screening campaign against T. cruzi TR. All 21 in vitro hits were used in a subsequent similarity search-based in silico screening on a database containing 200,000 physically available compounds. The similarity search resulted in a data set containing 1,204 potential TR inhibitors, which was subjected to a second in vitro screening campaign leading to 61 additional active compounds. This corresponds to an approximately 10-fold enrichment compared to the initial pure in vitro screening. In total, 82 novel TR inhibitors with activities down to the nM range could be identified proving the validity of our combined in vitro/in silico approach. Moreover, the four most active compounds, showing IC50 values of <1 µM, were selected for determining the inhibitor constant. In first on parasites assays, three compounds inhibited the proliferation of bloodstream T. brucei cell line 449 with EC50 values down to 2 µM.

Therapy in prion diseases.

In the last two decades, knowledge of the neurobiology of prion diseases or transmissible spongiform encephalopathies (TSE) has significantly advanced, but a successful therapy to stop or delay the progression of these disorders remains one of the most challenging goals of biomedical research. Several obstacles to this achievement are in common with other neurodegenerative disorders: difficulties to move from experimental level to clinical stage; appropriate timing of intervention; correct set up of clinical trial. Also in terms of molecular bases of disease, TSE and the other neurodegenerative disorders associated with protein misfolding such as Alzheimer, Parkinson and Huntington diseases, share a central pathogenic role of soluble small aggregates, named oligomers, considered the culprit of neuronal dysfunction: accordingly, these disorders could by termed oligomeropathies. However, the rapid progression of TSE, together with their clinical and molecular heterogeneity, make the therapeutic approach particularly problematic. The main target of the antiprion strategy has been the pathological form of the cellular prion protein (PrP(C)) termed PrP(Sc), invariably associated with the diseases. Several compounds have been found to affect PrP(Sc) formation or enhance its clearance in in vitro models, and prolong survival in experimental animals. However, few of them such as quinacrine and pentosan polysulfate have reached the clinical evaluation; more recently, we have conducted a clinical trial with doxycycline in patients with Creutzfeldt-Jakob disease without satisfactory results. In experimental conditions, active and passive immunization with antibodies against PrP and mucosal vaccination have shown to protect from peripheral infection. Other studies have proposed new potentially effective molecules targeting PrP oligomers. Furthermore, the possibility to interfere with PrP(C) to PrP(Sc) conversion by an active control of PrP(C) is another interesting approach emerging from experimental studies. However, in common with the other oligomeropathies, early diagnosis allowing to treat at risk population in a preclinical stage represent the more realistic perspective for efficient TSE therapy.

Phenotypic screening with oleaginous microalgae reveals modulators of lipid productivity.

Here we describe the first phenotypic screening with microalgae to study lipid metabolism and to discover organic small molecules as chemical triggers that increase growth and lipid production. A microplate assay has been developed for analysis of intracellular lipids using Nile Red fluorescence in order to screen a collection of diverse bioactive organic molecules (e.g., kinase inhibitors) with four strains of oleaginous microalgae (Nannochloropsis salina, Nannochloropsis oculata, Nannochloris sp., and Phaeodactylum tricornutum). Several small molecules identified in microplate screening increased lipid productivity >200% without decreasing growth and biomass production. Selected compounds were further investigated in the context of larger batch culture experiments (e.g., 500 mL) and demonstrated to increase lipid levels (up to 84%) while maintaining or increasing the specific growth rate. Bioactive molecules such as forskolin and quinacrine were identified as promising probes of microalgae lipid pathways. We have also determined that common antioxidants such as epigallocatechin gallate and butylated hydroxyanisole (BHA) increase lipid productivity and may represent new probes of oxidative signaling pathways for photooxidative protection.

Application of a novel microtitre plate-based assay for the discovery of new inhibitors of DNA gyrase and DNA topoisomerase VI.

DNA topoisomerases are highly exploited targets for antimicrobial drugs. The spread of antibiotic resistance represents a significant threat to public health and necessitates the discovery of inhibitors that target topoisomerases in novel ways. However, the traditional assays for topoisomerase activity are not suitable for the high-throughput approaches necessary for drug discovery. In this study we validate a novel assay for screening topoisomerase inhibitors. A library of 960 compounds was screened against Escherichia coli DNA gyrase and archaeal Methanosarcina mazei DNA topoisomerase VI. Several novel inhibitors were identified for both enzymes, and subsequently characterised in vitro and in vivo. Inhibitors from the M. mazei topoisomerase VI screen were tested for their ability to inhibit Arabidopsis topoisomerase VI in planta. The data from this work present new options for antibiotic drug discovery and provide insight into the mechanism of topoisomerase VI.

Quinacrine synergizes with 5-fluorouracil and other therapies in colorectal cancer.

Although treatments have improved patient prognosis in surgically resectable colorectal cancer, new effective drugs with improved safety profiles are needed to improve the currently poor outcomes of patients with recurrent or metastatic colorectal cancer. Quinacrine, a small molecule anti-malarial agent that has activity in giardiasis, lupus, prion disease, and used as a means of non-surgical sterilization, has shown cytotoxic activity across a broad range of cancers. Here, we evaluate the potential of adding quinacrine to anticancer chemotherapeutics and targeted agents as a potential novel combinatorial therapy for advanced colon cancer. We show that quinacrine synergizes with 5-fluorouracil and significantly enhances the cytotoxicity of sorafenib in a panel of 10 human colorectal cancer cell lines, including those with KRAS mutations protein gel blot analysis confirmed that quinacrine's anticancer activity partially arises from its ability to stabilize p53 and lower anti-apoptotic protein levels. In a series of in vivo studies, quinacrine monotherapy lowered the tumor load of nu/nu mice bearing human colorectal cancer xenografts. In combination, quinacrine and 5-Fluorouracil significantly delayed tumor growth of a variety of different xenografts, as compared to each agent administered alone. Our results suggest that the administration of quinacrine in combination with chemotherapeutic agents and targeted agents should be further explored in patients with recurrent, locally advanced, or metastatic colorectal cancer.

Role of phospholipase A(2) in prepulse inhibition of the auditory startle reflex in rats.

High levels of calcium-independent phospholipase A(2) (iPLA(2)) are present in the striatum and cerebral cortex [W.Y. Ong, J.F. Yeo, S.F. Ling, A.A. Farooqui, Distribution of calcium-independent phospholipase A(2) (iPLA(2)) in monkey brain, J. Neurocytol. 34 (2005) 447-458], and several clinical investigations have suggested a possible role of altered iPLA(2) activity in neurodegenerative and psychiatric disorders. The present study was carried out to elucidate a possible effect of PLA(2) on prepulse inhibition (PPI) of the acoustic startle reflex. Rats that received intraperitoneal injection of the non-specific PLA(2) inhibitor, quinacrine, showed significantly decreased PPI at 76, 80, and 84dB, compared to saline injected controls. In addition, rats that received intrastriatal injection of antisense oligonucleotide to iPLA(2) showed significant reduction in PPI at prepulse intensities of 76 and 84dB compared to scrambled sense injected controls. Together, these findings point to a role of PLA(2) in PPI of the auditory startle reflex and sensorimotor gating.

Binge ethanol-induced neurodegeneration in rat organotypic brain slice cultures: effects of PLA2 inhibitor mepacrine and docosahexaenoic acid (DHA).

Using rat organotypic hippocampal-entorhinal cortical (HEC) slice cultures, we examined whether phospholipase A2 (PLA2) activity is involved in binge alcohol (ethanol)-induced neurodegeneration, and whether docosahexaenoic acid (DHA; 22:6n-3), a fish oil-enriched fatty acid that is anti-inflammatory in brain damage models, is neuroprotective. Assessed with propidium iodide and lactate dehydrogenase (LDH) leakage, neurodamage from ethanol (6 days 100 mM ethanol with four withdrawal periods) was prevented by the PLA2 pan-inhibitor, mepacrine. Also, ethanol-dependent neurodegeneration-particularly in the entorhinal region-was significantly ameliorated by DHA supplementation (25 microM); however, adrenic acid, a 22:4n-6 analog, was ineffective. Consistent with PLA2 activation, [(3)H] liberation was approximately fivefold greater in [(3)H]arachidonic acid-preloaded HEC slice cultures during ethanol withdrawal compared to controls, and DHA supplementation suppressed [(3)H] release to control levels. DHA might antagonize PLA2 activity directly or suppress upstream activators (e.g., oxidative stress); however, other DHA mechanisms could be important in subdueing ethanol-induced PLA2-dependent and independent neuroinflammatory processes.

Gene expression profile of quinacrine-cured prion-infected mouse neuronal cells.

Prion diseases are transmissible fatal neurodegenerative diseases of humans and animals, characterised by the presence of an abnormal isoform (scrapie prion protein; PrP(Sc)) of the endogenous cellular prion protein (PrP(C)). The pathological mechanisms at the basis of prion diseases remain elusive, although the accumulation of PrP(Sc) has been linked to neurodegeneration. Different genomic approaches have been applied to carry out large-scale expression analysis in prion-infected brains and cell lines, in order to define factors potentially involved in pathogenesis. However, the general lack of overlap between the genes found in these studies prompted us to carry an analysis of gene expression using an alternative approach. Specifically, in order to avoid the complexities of shifting gene expression in a heterogeneous cell population, we used a single clone of GT1 cells that was de novo infected with mouse prion-infected brain homogenate and then treated with quinacrine to clear PrP(Sc). By comparing the gene expression profiles of about 15 000 genes in quinacrine-cured and not cured prion-infected GT1 cells, we investigated the influence of the presence or the absence of PrP(Sc). By real-time PCR, we confirmed that the gene encoding for laminin was down-regulated as a consequence of the elimination of PrP(Sc) by the quinacrine treatment. Thus, we speculate that this protein could be a specific candidate for further analysis of its role in prion infection and pathogenesis.

Pharmaceutical agents known to produce disulfiram-like reaction: effects on hepatic ethanol metabolism and brain monoamines.

Several pharmaceutical agents produce ethanol intolerance, which is often depicted as disulfiram-like reaction. As in the case with disulfiram, the underlying mechanism is believed to be the accumulation of acetaldehyde in the blood, due to inhibition of the hepatic aldehyde dehydrogenases. In the present study, chloramphenicol, furazolidone, metronidazole, and quinacrine, which are reported to produce a disulfiram-like reaction, as well as disulfiram, were administered to Wistar rats and the hepatic activities of alcohol and aldehyde dehydrogenases (1A1 and 2) were determined. The expression of aldehyde dehydrogenase 2 was further assessed by Western blot analysis, while the levels of brain monoamines were also analyzed. Finally, blood acetaldehyde was evaluated after ethanol administration in rats pretreated with disulfiram, chloramphenicol, or quinacrine. The activity of aldehyde dehydrogenase 2 was inhibited by disulfiram, chloramphenicol, and furazolidone, but not by metronidazole or quinacrine. In addition, although well known for metronidazole, quinacrine also did not increase blood acetaldehyde after ethanol administration. The protein expression of aldehyde dehydrogenase 2 was not affected at all. Interestingly, all substances used, except disulfiram, increased the levels of brain serotonin. According to our findings, metronidazole and quinacrine do not produce a typical disulfiram-like reaction, because they do not inhibit hepatic aldehyde dehydrogenase nor increase blood acetaldehyde. Moreover, all tested agents share the common property to enhance brain serotonin, whereas a respective effect of ethanol is well established. Therefore, the ethanol intolerance produced by these agents, either aldehyde dehydrogenase is inhibited or not, could be the result of a "toxic serotonin syndrome," as in the case of the concomitant use of serotonin-active medications.

Chelating compound, chrysoidine, is more effective in both antiprion activity and brain endothelial permeability than quinacrine.

1. As an extension of our previous study of quinacrine and its derivatives, chelating chemicals were screened to obtain more effective, better brain-permeable antiprion compounds using either prion-infected neuroblastoma cells or brain capillary endothelial cells.2. Eleven chemicals were found to have antiprion activity. Most of them shared a common structure consisting of benzene or naphthalene at either end of an azo bond. Structure-activity data suggest that chelating activity is not necessary but might contribute to the antiprion action.3. Chrysoidine, a representative compound found here, was about 27 times more effective in the antiprion activity and five times more efficiently permeable through the brain capillary endothelial cells than quinacrine was.4. These chemicals might be useful as compounds for development of therapeutics for prion diseases.

Potent inhibition of scrapie prion replication in cultured cells by bis-acridines.

Prion diseases are characterized by an accumulation of PrP(Sc), a misfolded isoform of the normal cellular prion protein, PrP(C). We previously reported the bioactivity of acridine-based compounds against PrP(Sc) replication in scrapie-infected neuroblastoma cells and now report the improved potency of bis-acridine compounds. Bis-acridines are characterized by a dimeric motif, comprising two acridine heterocycles tethered by a linker. A library of bis-(6-chloro-2-methoxy-acridin-9-yl) and bis-(7-chloro-2-methoxy-benzo[b][1,5]naphthyridin-10-yl) analogs was synthesized to explore the effect of structurally diverse linkers on PrP(Sc) replication in scrapie-infected neuroblastoma cells. Structure-activity analysis revealed that linker length and structure are important determinants for inhibition of prion replication in cultured scrapied cells. Three bis-acridine analogs, (6-chloro-2-methoxy-acridin-9-yl)-(3-[4-[3-(6-chloro-2-methoxy-acridin-9-ylamino)-propyl]-piperazin-1-yl]-propyl)-amine, N,N'-bis-(6-chloro-2-methoxy-acridin-9-yl)-1,8-diamino-3,6-dioxaoctane, and (1-[[4-(6-chloro-2-methoxy-acridin-9-ylamino)-butyl]-[3-(6-chloro-2-methoxy-acridin-9-ylamino)-propyl]-carbamoyl]-ethyl)-carbamic acid tert-butyl ester, showed half-maximal inhibition of PrP(Sc) formation at 40, 25, and 30 nM, respectively, and were not cytotoxic to uninfected neuroblastoma cells at concentrations of 500 nM. Our data suggest that bis-acridine analogs may provide a potent alternative to the acridine-based compound quinacrine, which is currently under clinical evaluation for the treatment of prion disease.

[Therapeutics for prion diseases].

Recent outbreaks of acquired forms of human prion diseases in younger people are promoting the development of prophylaxis and therapeutics. One possible target for therapeutic interventions is to inhibit the biosynthesis and accumulation of an abnormal isoform of prion protein, which is supposed to be a pathogen itself. Here, our current in-vitro and in-vivo data on anti-prion chemicals with amyloid binding capacity, represented by pentosan polysulfate and thioflavin-related chemicals, are presented, and structural aspects on the interaction between prion protein molecules and anti-prion chemicals including quinacrine are discussed. The current status of clinical trials using quinacrine or pentosan polysulfate is also reviewed. Finally, key structure(s) in the prion protein molecules, important to inhibit the conversion into abnormal prion protein molecules, are discussed in terms of pharmacology, and possibility of the in-silico rational drug design is also referred. Exploitation of anti-prion drugs should facilitate to solve the enigma of "prion" which can be the only creature against the central dogma, in addition to its contributing to the people with the illness or the people in high risks.

Loss of natural killer cell activity after murine tumor transplantation appears as a consequence of dietary lipid administration.

It is generally assumed that unsaturated fatty acids are important biological mediators that may be applied in the treatment of patients suffering from autoimmune disorders, in the modulation of tumorigenic processes or in the induction or inhibition of apoptosis. In this study, mice divided into three groups were fed dietary lipids; olive oil (20% w/w), fish oil (20% w/w) or hydrogenated coconut oil (20% w/w) for four weeks. Then, survival percentage, natural killer (NK) cell activity and lipid peroxidation were measured after murine lymphoma (LSTRA) transplantation. Survival percentage showed a reduced resistance to LSTRA tumor in mice fed fish oil diet and generaly loss of NK cell activity was observed after lymphoma transplantation. Lipid peroxidation from mice fed dietary lipids was measured in the presence of both phospholipase and cyclooxygenase inhibitors. In general, the data contained in this paper point to a detrimental effect caused by dietary lipids in mice transplanted with a lymphoma.

Two phenanthraquinones from Dendrobium moniliforme.

Two phenanthraquinones were isolated from the stems of Dendrobium moniliforme. They were identified by interpretation of spectral data as 2,6-dimethoxy-1,4,5,8-phenanthradiquinone and 5-hydroxy-3,7-dimethoxy-1,4-phenanthraquinone, named moniliformin (1) and denbinobin (2), respectively. This is the first report of compound 1, which possesses a novel 1,4,5,8-diquinone moiety in the phenanthraquinone skeleton. Compound 2 showed potent antiinflammatory effects in vitro.