Genomics of Aminoglycoside Resistance in Pseudomonas aeruginosa Bloodstream Infections at a United States Academic Hospital

Pseudomonas aeruginosa frequently becomes resistant to aminoglycosides by the acquisition of aminoglycoside modifying enzyme (AME) genes and the occurrence of mutations in the mexZ, fusA1, parRS, and armZ genes. We examined resistance to aminoglycosides in a collection of 227 P. aeruginosa bloodstream isolates collected over 2 decades from a single United States academic medical institution. Resistance rates of tobramycin and amikacin were relatively stable over this time, while the resistance rates of gentamicin were somewhat more variable. For comparison, we examined resistance rates to piperacillin-tazobactam, cefepime, meropenem, ciprofloxacin, and colistin. Resistance rates to the first four antibiotics were also stable, although uniformly higher for ciprofloxacin. Colistin resistance rates were initially quite low, rose substantially, and then began to decrease at the end of the study. Clinically relevant AME genes were identified in 14% of isolates, and mutations predicted to cause resistance were relatively common in the mexZ and armZ genes. In a regression analysis, resistance to gentamicin was associated with the presence of at least one gentamicin-active AME gene and significant mutations in mexZ, parS, and fusA1. Resistance to tobramycin was associated with the presence of at least one tobramycin-active AME gene. An extensively drug-resistant strain, PS1871, was examined further and found to contain five AME genes, most of which were within clusters of antibiotic resistance genes embedded in transposable elements. These findings demonstrate the relative contributions of aminoglycoside resistance determinants to P. aeruginosa susceptibilities at a United States medical center. IMPORTANCE Pseudomonas aeruginosa is frequently resistant to multiple antibiotics, including aminoglycosides. The rates of resistance to aminoglycosides in bloodstream isolates collected over 2 decades at a United States hospital remained constant, suggesting that antibiotic stewardship programs may be effective in countering an increase in resistance. Mutations in the mexZ, fusA1, parR, pasS, and armZ genes were more common than acquisition of genes encoding aminoglycoside modifying enzymes. The whole-genome sequence of an extensively drug resistant isolate indicates that resistance mechanisms can accumulate in a single strain. Together, these results suggest that aminoglycoside resistance in P. aeruginosa remains problematic and confirm known resistance mechanisms that can be targeted for the development of novel therapeutics.

Painful Convictions: Examining Pain Management Malpractice Claims From Incarcerated Patients, 2000-2020

We aim to characterize the legal landscape of incarcerated patients' pain management malpractice claims and to discuss the ethical and policy implications that result. The most common rationales for lawsuits were failure to completely treat (38 [46.3%]), failure to offer (34 [41.4%]), and delay of treatment (6 [7.3%]). In cases won by defendants, the most common rationale for verdicts was no deliberate indifference occurred (74 [86.6%]). We found that incarcerated individuals were often unsuccessful in litigating claims for inadequate pain management despite several cases pointing toward treatment strategies far below what would be ethically accepted as standard of care in the community setting.

Severe Shivering on Venoarterial Extracorporeal Membrane Oxygenation-Raising the Circuit Temperature to Stop Rhabdomyolysis: A Case Report

We report a case of severe shivering resulting in rhabdomyolysis while on venoarterial extracorporeal membrane oxygenation (ECMO) that resolved after hyperthermia was induced using the ECMO circuit. The patient developed shivering approximately 24 hours after venoarterial ECMO cannulation for refractory ventricular tachycardia. The shivering caused rhabdomyolysis and necessitated cisatracurium infusion. The shivering failed to resolve after the patient was diagnosed and treated for ventilator-associated pneumonia. Suspecting sepsis as the etiology of shivering, the ECMO circuit temperature was increased to 38 °C, and the shivering was resolved. This case demonstrates therapeutic hyperthermia to treat infection-induced severe shivering and rhabdomyolysis while on ECMO.

The Effect of Homelessness on Patient Wait Times in the Emergency Department

BACKGROUND

Prolonged emergency department (ED) wait times could potentially lead to increased morbidity and mortality. While previous work has demonstrated disparities in wait times associated with race, information about the relationship between experiencing homelessness and ED wait times is lacking.

OBJECTIVES

The purpose of this study was to explore the relationship between residence status (undomiciled vs. domiciled) and ED wait times. We hypothesized that being undomiciled would be associated with longer wait times.

METHODS

We obtained data from the National Hospital Ambulatory Medical Care Survey from 2014 to 2017. We compared wait times in each triage category using t tests. We used multivariate linear regression to explore associations between residence status and wait times while controlling for other patient- and hospital-level variables.

RESULTS

On average, undomiciled patients experienced significantly longer mean ED wait times than domiciled patients (53.4 vs. 38.9 min; p < 0.0001). In the multivariate model, undomiciled patients experienced significantly different wait times by 15.5 min (p = 0.0002). Undomiciled patients experienced increasingly longer waits vs. domiciled patients for the emergent and urgent triage categories (+33.5 min, p < 0.0001, and +22.7 min, p < 0.0001, respectively).

CONCLUSIONS

Undomiciled patients experience longer ED wait times when compared with domiciled patients. This disparity is not explained by undomiciled patients seeking care in the ED for minor illness, because the disparity is more pronounced for urgent and emergent triage categories.

Off-Label studies on anakinra in dermatology: a review

Purpose: Anakinra (Kineret^®) is an interleukin-1 receptor antagonist (IL-1Ra) FDA approved for use in rheumatoid arthritis and in neonatal-onset multisystem inflammatory disease (NOMID). It has been used off-label for a variety of dermatologic conditions. A review of the available studies and cases of these off-label uses would be valuable to the dermatologist considering alternative treatments for these oftentimes poorly studied conditions.Materials and methods: The PubMed/MEDLINE, EMBASE, Scopus, and ClinicalTrials.gov databases were searched with the term 'anakinra.' Results were manually screened to identify published data on off-label uses of anakinra in dermatologic conditions and systemic conditions with prominent dermatologic manifestations.Results: Anakinra appears to show efficacy for numerous dermatologic conditions, with the strongest evidence for hidradenitis suppurativa, Bechet's disease, Muckle-Wells syndrome, and SAPHO syndrome. Case reports and case series data are available for numerous other dermatologic conditions.Conclusion: Anakinra is a potential option for patients with certain difficult-to-treat dermatologic diseases, given its relatively benign adverse effect profile and its effectiveness in a wide array of conditions. Overall, anakinra appears to be a promising option in the treatment of numerous dermatologic inflammatory conditions refractory to first line therapies, but further and higher-quality data is needed to clarify its therapeutic role.

Off-label studies on tofacitinib in dermatology: a review

PURPOSE

Tofacitinib citrate is an oral Janus kinase 1/3 inhibitor approved for rheumatoid arthritis, ulcerative colitis, and active psoriatic arthritis. Tofacitinib is being increasingly used off-label for dermatological conditions, with varying efficacy across recent studies. A review of these studies will be a helpful resource for dermatologists considering the use of tofacitinib for conditions refractory to first-line therapies.

MATERIALS AND METHODS

MEDLINE, Embase, CINAHL Plus, Cochrane Library, Scopus, Web of Science, Clinicaltrials.gov, and the WHO International Clinical Trials Registry Platform were all searched for articles and trials mentioning the term 'tofacitinib', then manually reviewed to identify published data on off-label uses of tofacitinib. The article was structured according to the quality of the evidence available.

RESULTS

Tofacitinib appears to show strong efficacy for numerous dermatologic conditions. Randomized controlled trial data is available for atopic dermatitis, alopecia areata, and plaque psoriasis. Case report and case series data is available for numerous other dermatologic conditions.

CONCLUSION

While tofacitinib has a wide array of immunoregulatory properties, making it a possible candidate for treating many dermatologic conditions refractory to other treatments, further testing is needed to better characterize its efficacy and utility moving forward, as well as its safety and adverse effect profile.

The effect of extracellular pH on angiogenesis in vitro

The microenvironment of the majority of solid tumours in which new vessels must grow and survive is acidic. Whilst recent reports suggest a role of the low tumour pH in the invasive and metastatic potential of tumour cells, little is known as to its impact on angiogenesis. The three-dimensional in vitro rat aortic ring model was used to study the effects of low extracellular pH (pH(e)) on microvascular growth. The spontaneous angiogenic response in collagen gels was seen to be highly dependent on the pH of the culture medium, with optimal outgrowth at pH 7.4, and a marked delay in microvascular growth at pH 6.9. This inhibition of vascular development was reversible. The absence of similar effects of medium pH on monolayer outgrowths of endothelial cells from rat aortic rings suggested an effect of pH(e) on aspects specific to three-dimensional growth. Vascular endothelial growth factor and basic fibroblast growth factor, whilst having limited effects at pH 7.4, were seen to reduce the time to onset of vessel outgrowth at pH 7.1, and lead to an initial growth rate similar to that observed at pH 7.4 in the absence of growth factors. Thus, the low environmental pH encountered by endothelial cells in solid tumours would not necessarily be detrimental to neovascularisation: a prominent in vitro angiogenic response is still observed at low pH(e) when stimulated by exogenous growth factors, high concentrations of which would be present in vivo.

Induction of cyclin E and inhibition of DNA synthesis by the novel acronycine derivative S23906-1 precede the irreversible arrest of tumor cells in S phase leading to apoptosis

S23906-1 is a diester derivative of 1,2-dihydrobenzo[b]acronycine with an unknown mechanism of action. This cytotoxic compound was 20-fold more potent than acronycine in inhibiting the proliferation of six tumor cell lines. Using a clonogenic assay of cell survival, the HT29 human colon carcinoma cell line was 100-fold more sensitive to S23906-1 than acronycine. Cell cycle analysis, by flow cytometry, showed that S23906-1 induced a partially reversible arrest of HT29 cells in G2+M at 1 microM and below and an irreversible arrest in S phase at 2.5 microM and above. These cell cycle effects were followed by cell death through apoptosis, quantified by annexin-V labeling. Inhibition of DNA synthesis was observed by complete prevention of bromodeoxyuridine (BrdU) incorporation after only 4 h of incubation with 5 microM S23906-1. Interestingly, under the same experimental conditions, a significant increase of cyclin E protein level was observed without any modification of cyclins D1, D2, D3, or A. This overexpressed cyclin E protein was not complexed with Cdk2, as shown by western blotting for Cdk2 in immunoprecipitates of cyclin E. Similar inhibition of BrdU incorporation and elevation of cyclin E protein were observed after treatment with cytosine arabinoside, which reversibly inhibited progression into S phase, but not after DNA damage induced by cisplatin. S23906-1 thus has a novel mechanism of action. A cell line resistant to S23906-1 showed that overexpression of cyclin E was implicated in the novel cytotoxic activity of this compound.

Synthesis, cytotoxic activity, NMR study and stereochemical effects of some new pyrano[3,2-b]thioxanthen-6-ones and pyrano[2,3-c]thioxanthen-7-ones

Some new substituted pyrano[3,2-b]thioxanthen-6-ones and pyrano[2,3-c]thioxanthen-7-ones were prepared and their cytotoxic activity was evaluated using acronycine as the reference compound. The conformation of the molecules was also investigated in an effort to correlate this parameter with the biological activity.

Synthesis and cytotoxic activity of benzophenanthrolinone analogues of acronycine

Condensation of either 2-bromobenzoic acid (4) or 2-chloro-3-nitrobenzoic acid (5) with suitable aminoquinolines 6-8 afforded phenylquinolylamines 9-13. Acid mediated cyclization gave the corresponding 12H-benzo[b][1,7]phenanthrolin-7-ones 14 and 15, and 12H-benzo[b][1,10]phenanthrolin-7-ones 16-18. Compounds 14, 16, and 17 were subsequently N-methylated to 6-demethoxyacronycine and acronycine analogues 19-21, whereas reduction of the aromatic nitro group of 18 gave the amino derivative 22. Unsubstituted 12H-benzo[b][1,10]phenanthrolin-7-ones 16, 17, 20, and 21 were devoid of significant cytotoxic activity, whereas 18 and 22, bearing a nitrogen substituent at position 11, were significantly active. Unsubstituted 12H-benzo[b][1,7]phenanthrolin-7-ones 14 and 19, which include a pyridine nitrogen in the same 4-position as the pyran oxygen of acronycine exhibited cytotoxic activities within the same range of magnitude as acronycine itself.

Design, synthesis and antiproliferative activity of tripentones: a new series of antitubulin agents

Structure-activity relationship studies of a new series of tripentones (thieno[2,3-b]pyrrolizin-8-ones), led us to prepare several derivatives with antiproliferative activities. The most promising 3-(3-hydroxy-4-methoxyphenyl)thieno[2,3-b]pyrrolizin-8-one 20 (leukemia L1210, IC(50)=15 nM) was shown to be a potent inhibitor of tubulin polymerization.

A reappraisal of the potential chemopreventive and chemotherapeutic properties of resveratrol

Resveratrol, a phytoalexin found in grapes and wines, has been reported to exhibit a wide range of pharmacological properties and is believed to play a role in the prevention of human cardiovascular disease (the so-called 'French paradox'). This molecule may also play a major role in both cancer prevention and therapy. In this review article we summarize the recent advances that have provided new insights into the molecular mechanisms underlying the promising properties of resveratrol. These include cyclooxygenase, nitric oxide synthase and cytochrome P450 inhibition, as well as cell cycle effects, apoptosis modulation and hormonal activity.

Marked antitumor activity of a new potent acronycine derivative in orthotopic models of human solid tumors

S 23906-1 is a novel acronycine derivative selected on the basis of its potency in vitro. We investigated the antitumor activity of S 23906-1 against several murine transplantable tumors (C38 colon carcinoma, P388 leukemia, B16 melanoma, and Lewis lung carcinoma) and in orthotopic models of human lung (NCI-H460 and A549), ovarian (IGROV1 and NIH:OVCAR-3), and colorectal cancers (HCT116 and HT-29). Against established C38 colon carcinoma, S 23906-1 administered twice i.v. from 1.56-6.25 mg/kg markedly inhibited tumor growth. Treatment at the optimal dose (6.25 mg/kg) induced tumor regression in all of the mice. Acronycine was 16-fold less potent and only moderately active at the maximum tolerated dose, 100 mg/kg. Against other murine tumors of the former National Cancer Institute panel, S 23906-1 was either only moderately active or totally inactive. When evaluated in human orthotopic models, S 23906-1 given p.o. or i.v. demonstrated a marked antitumor activity against human carcinomas. In the two human lung cancer models, S 23906-1 increased the survival of the animals in a dose-dependent manner and induced treated versus control values of 162% (NCI-H460) and 193% (A549). Vinorelbine was less active, with treated versus control values of 119% and 174%, respectively. A significant survival benefit was also observed against the two i.p. ovarian tumors in which S 23906-1 was as active as paclitaxel, inducing 80% long-term survivors in the NIH:OVCAR-3 model. Lastly, S 23906-1 inhibited the growth of primary HT-29 and HCT116 colon tumors grafted onto the cecum as efficiently as irinotecan and eradicated the formation of lymph node, hepatic, and pulmonary metastases in the aggressive HCT116 model. The novel spectrum of activity of S 23906-1 compared with existing anticancer agents warrants further preclinical investigation.

Synthesis and cytotoxic activity of benzopyranoxanthone analogues of benz

Condensation of 3-hydroxy-2-naphthalenecarboxylic acid with phloroglucinol afforded 1,3-dihydroxy-12H-benzo[b]xanthen-12-one. Construction of an additional dimethylpyran ring onto this skeleton, by alkylation with 3-chloro-3-methyl-1-butyne followed by Claisen rearrangement, gave access to a series of benzo[b]pyrano[2,3-i]xanthen-6-ones and benzo[b]pyrano[3,2-h]xanthen-7-ones related to psorospermine and benzo[b]acronycine. In contrast with what is observed in the pyridoacridone and benzopyridoacridone series, the linear benzo[b]-pyrano[2,3-i]xanthen-6-one derivatives were more potent than their angular benzo[b]pyrano[3,2-h]xanthen-7-one isomers. cis-3,4-Diacetoxy-5-methoxy-2,2-dimethyl-3,4-dihydro-2H,6H-benzo[b]pyrano[2,3-i]xanthen-6-one, the most active among the new compounds, was more potent than acronycine in inhibiting the proliferation of L1210 murine leukemia cells.

Synthesis and cytotoxicity of artemisinin derivatives containing cyanoarylmethyl group

A series of 12alpha-deoxoartemisinyl cyanoarylmethyl dicarboxylates (4a-4o), dicarboxylic acids 12alpha-deoxoartemisinyl ester cyanoarylmethyl amide (5a-5k), and dicarboxylic acids 12alpha-deoxoartemisinyl ester N-methylcyanoarylmethyl amide (6a-6l), showing moderate cytotoxicity against P388 and L1210 cells were prepared. They induced the significant accumulation of L1210 and P388 cells in the G1 phase of the cell cycle. This mechanism of action was quite different from that of the majority of cytotoxic compounds used in the chemotherapy of cancer. Compound 4b possessed better cytotoxicity than the other compounds.

2,2-Dimethyl-2H-anthra[2,3-b]pyran-6,11-diones: a new class of cytotoxic compounds

The synthesis and cytotoxic activity of some new 2,2-dimethyl-2H-anthra[2,3-b]pyran-6,11-diones is described. Certain compounds possess interesting activity against murine leukemia L-1210 cells. Relationships between the biological activity and the pyrano-ring conformations are discussed.

General synthesis of alpha-substituted 3-bisaryloxy propionic acid derivatives as specific MMP inhibitors

Modulations of alpha and aryl substitutions on 3-aryloxy propionic acid hydroxamates led to novel and potent inhibitors of MMP-2,3,9 and 13, and selectivity versus MMP-1.

From peptide libraries to optimized nonpeptide ligands in the search for S-farnesyltransferase inhibitors

A complete 331,776-member library of tetrapeptides made of 24 amino acid building blocks was synthesized robotically on solid phase and subjected to a deconvolution based on the inhibitory potency of the sublibraries in a HPLC assay of the S-farnesyltransferase activity in vitro. One of the non-natural peptide and noncysteine-containing leads Nip-Trp-Phe-His (Nip=p-nitrophenyl-L-alanine) was optimized chemically to give a proteolytically stable pseudopeptide with a 200-fold potency compared with the original lead. The final compound was converted to the C-terminal ethyl ester: p-F-C6H4-CO(CH2)2-CO-Bta-D-Phepsi[CH2NH]His-OEt (Bta = benzothienyl-L-alanine) and shown to behave as a prodrug which was hydrolyzed back to the C-terminal acid following cell penetration. The method confirmed that several structurally original leads can be discovered in large libraries when deconvolution relies upon a highly specific assay and that these leads can be optimized by chemical modification to impart the final compound the desired pharmacological and pharmacokinetic properties.

Synthesis of a novel series of cytotoxic bisindole alkaloids

Original cytotoxic bisindole alkaloids with a 1,2,3,4-tetrahydroquinoline bridge were synthesized by reductive amination with various anilines. The most cytotoxic compounds display a high and dose-dependent cell cycle effect with accumulation in the G1 phase. Influence of substitution of the starting aniline on the reaction and on cytotoxicity of produced dimers was pointed out.

Novel antitumor artemisinin derivatives targeting G1 phase of the cell cycle

Modification of artemisinin structure led us to the discovery of a novel class of antitumor compounds. These artemisinin derivatives containing cyano and aryl groups showed potent antiproliferative effect in vitro against P388 and A549 cells. This activity was reflected in P388 murine leukemia by an accumulation of cells in G1 phase, and induction of apoptosis.

In vitro and in vivo pharmacological characterizations of the antitumor properties of two new olivacine derivatives, S16020-2 and S30972-1

S16020-2, a new olivacine derivative and a topoisomerase II inhibitor, has recently entered clinical trials. New analogues and derivatives have been synthesized from the S16020-2 compound. Preliminary data indicate that S30972-1, one of these S16020-2 derivatives, may exhibit a comparatively higher level of antitumor potency associated with an improved therapeutic index than does S16020-2. The antitumor activities of S16020-2 and S30972-1 were therefore characterized both in vitro and in vivo, with Adriamycin and etoposide chosen as reference compounds. The in vitro data show that S30972-1 is a topoisomerase II inhibitor, mediating its activity through an ATP-dependent mechanism such as S16020-2. The two olivacine derivatives exhibited similar activities in vitro at the levels of the global growth of six human cancer cell lines, of the induction of apoptosis, and of the G2 cell cycle phase arrest. The in vivo antitumor activity characterization included the use of two murine leukemia types (P388-LEU and L1210-LEU), two murine lymphoma-like models (P388-LYM and L1210-LYM), two mammary adenocarcinomas (MXT-HI and MXT-HS), and one melanoma (B16). The data show that S30972-1 is actually more efficient in vivo than S16020-2, a feature that may relate to the fact that S30972-1 is less toxic than S16020-2. The S30972-1 compound exhibited in vivo a level of antitumor activity that was also actually higher than that exhibited by Adriamycin and similar to that exhibited by etoposide.

Expression of vascular endothelial growth factor (VEGF) and VEGF receptors in human neuroblastomas

BACKGROUND

Vascular endothelial growth factor (VEGF) is a specific endothelial cell mitogen that stimulates angiogenesis and plays a crucial role in tumor growth. The aim of the present study was to evaluate the expression of VEGF and of its two high-affinity tyrosine kinase receptors (KDR and Flt-1) in neuroblastoma surgical samples and cell lines.

PROCEDURE

The VEGF, KDR, and Flt-1 mRNA expression in neuroblastoma surgical samples and cell lines was studied by RT-PCR. The receptors were identified in [(125)I]VEGF binding and in functional studies (effect on cell growth). VEGF production by neuroblastomas was investigated by the ELISA method.

RESULTS

It was possible to observe the mRNAs encoding for VEGF and its two receptors in some of the surgical specimens examined, including most of the high-grade tumors. It was also possible to demonstrate that the SK-N-BE cell line expressed VEGF, KDR, and Flt-1 mRNAs as well as biologically active receptors: The cells bound [(125)I]-VEGF, and their growth was stimulated by exogenous VEGF. Moreover, VEGF protein could be detected in their culture conditioned medium.

CONCLUSIONS

These results suggest that, in addition to its effect on angiogenesis, VEGF may affect neuroblastoma cell growth directly and could be an autocrine growth factor.

Eriochrome Black T inhibits endothelial cell growth through S-phase blockade

We used human umbilical vein endothelial cells (HUVEC) cultures to investigate in vitro the antiproliferative effects of suramin and of its analogue, Eriochrome Black T. The cell cycle phases of interest were characterised with specific immune sera raised against cyclin D(1), cyclin E and proliferating nuclear cell antigen (PCNA). Simultaneous detection of two cell cycle markers was ensured by double colour immunofluorescence. Both compounds inhibited the endothelial cell growth while Eriochrome Black T was more potent than suramin. Suramin induced HUVEC to accumulate in G1-phase as an increase of the number of cells expressing both cyclin D(1) and PCNA was observed. Eriochrome Black T preferentially blocked them in the early S-phase, as it increased the proportion of cyclin E positive cells. These results suggest that in addition of its more potent antiproliferative effect on endothelial cell growth, Eriochrome Black T acts at another molecular level than suramin.

Synthesis and cytotoxic and antitumor activity of benzo[b]pyrano[3, 2-h]acridin-7-one analogues of acronycine

Benzo¿băcronycine (6-methoxy-3,3,14-trimethyl-3, 14-dihydro-7H-benzo¿bpyrano¿3,2-hăcridin-7-one, 4), an acronycine analogue with an additional aromatic ring linearly fused on the natural alkaloid basic skeleton, was synthesized in three steps, starting from 3-amino-2-naphthalenecarboxylic acid (5). Eight 1, 2-dihydroxy-1,2-dihydrobenzo¿băcronycine esters and diesters (17-24) were obtained by catalytic osmic oxidation, followed by acylation. All these compounds were significantly more cytotoxic than acronycine, when tested against L1210 leukemia cells in vitro. The potency of the cyclic carbonate 24 was in the range of the most active drugs currently used in cancer chemotherapy. Two selected diesters (17 and 24) were evaluated in vivo against P388 leukemia and colon 38 adenocarcinoma implanted in mice. Both compounds were markedly active at doses 16-fold lower than the dose of acronycine itself. Against colon 38 adenocarcinoma, compounds 17 and 24 were highly efficient, inhibiting tumor growth by more than 80%. Diacetate 17 was the most active, inhibiting tumor growth by 96% at 6.25 mg/kg, with two of seven mice being tumor-free on day 43.

Synthesis and cytotoxic activity of 2-dialkylaminoethylamino substituted xanthenone and thioxanthenone derivatives

The synthesis and biological evaluation of some new pyranoxanthenones and pyranothioxanthenones, substituted with flexible amino side-chains, and their evaluation as potential antitumor agents is described. The cytotoxic activity of the compounds and their eventual selective effect on a phase of the cell cycle were evaluated in vitro, using the murine lymphocytic L1210 leukemia cell line. The new aminoderivatives exhibited highly potent cytotoxicity against the leukemia L1210 cell line when compared to acronycine. All the compounds induced a partial accumulation of cells in the G2 + M phase of the cell cycle.

Expression of vascular endothelial growth factor (VEGF) and VEGF receptors in human neuroblastomas

BACKGROUND

Vascular endothelial growth factor (VEGF) is a specific endothelial cell mitogen that stimulates angiogenesis and plays a crucial role in tumor growth. The aim of the present study was to evaluate the expression of VEGF and of its two high-affinity tyrosine kinase receptors (KDR and Flt-1) in neuroblastoma surgical samples and cell lines.

PROCEDURE

The VEGF, KDR, and Flt-1 mRNA expression in neuroblastoma surgical samples and cell lines was studied by RT-PCR. The receptors were identified in [(125)I]VEGF binding and in functional studies (effect on cell growth). VEGF production by neuroblastomas was investigated by the ELISA method.

RESULTS

It was possible to observe the mRNAs encoding for VEGF and its two receptors in some of the surgical specimens examined, including most of the high-grade tumors. It was also possible to demonstrate that the SK-N-BE cell line expressed VEGF, KDR, and Flt-1 mRNAs as well as biologically active receptors: The cells bound [(125)I]-VEGF, and their growth was stimulated by exogenous VEGF. Moreover, VEGF protein could be detected in their culture conditioned medium.

CONCLUSIONS

These results suggest that, in addition to its effect on angiogenesis, VEGF may affect neuroblastoma cell growth directly and could be an autocrine growth factor.

Design, synthesis and biological activity of 7-O-(4-O-acetyl-3-iodo-2,3,6-trideoxy-alpha-L-arabino-hexopyranosyl) daunomycinone and 7-O-(3-chloro-2,3,6-trideoxy-4-O-propanoyl-alpha-L-lyxo- hexopyranosyl)daunomycinone

The synthesis and pharmacological evaluation of 7-O-(4-O-acetyl-3-iodo-2,3,6-trideoxy-alpha-L-arabino-hexopyranosyl) daunomycinone and 7-O-(3-chloro-2,3,6-trideoxy-4-O-propanoyl-alpha-L-lyxo-hexopyrano syl) daunomycinone are described. Their cytotoxic activity was evaluated against normal and resistant cell lines. Both compounds exhibited activity against the adriamycin resistant cell line KB-A1. These results support the hypothesis that the increased lipophilicity of the sugar part of anthracyclines is associated with their ability to overcome multidrug resistance (MDR).

Characterization of TNP-470-induced modifications to cell functions in HUVEC and cancer cells

The aim of the present work is to characterize (both in vitro and in vivo) the influence of TNP-470 on different cell functions involved in angiogenesis and, more particularly, on endothelial cell growth, cell migration and vessel formation. In addition, a possible direct anti-tumor activity was investigated. To this end, we made use in vitro of human umbilical cord endothelial vein (HUVEC) cells and two human cancer cell lines. The TNP-470 effects on the growth of cancer cell lines were compared to those of Taxol (an inhibitor of microtubule depolymerization), a cytotoxic reference which also displays strong antiogenic activity at low (non-toxic) doses. The in vitro effects were characterized on the mouse mammary MXT adenocarcinoma, on which we also characterized the influence of three clinically active anti-tumor compounds (as cytotoxic references). The purpose of this part of the study was to determine the actual TNP-470-related anti-tumor activity and to evaluate the possible toxic side-effects at the doses at which this compound induces tumor growth inhibition. These investigations were completed by analyzing the TNP-470 effects on HUVEC cell motility and in vitro and in vivo vessel formation. The results show that in vitro, TNP-470 inhibited the growth not only of HUVEC, but also of neoplastic cells. Furthermore, TNP-470 clearly inhibited in vitro endothelial cell motility (p<10(-5)). However, it had only a minor effect (p=0.02) on the formation of HUVEC cell networks on Matrigel(R). In vivo, TNP-470 was able to inhibit tumor growth (on the MXT model) at a dose (50 mg/kg) associated with toxic side-effects. Histological examination showed a significant inhibition of vessel formation (p<0.001) at high (toxic) and intermediary (non-toxic) doses (50 and 20 mg/kg). However, we also observed that TNP-470 stimulated lymphocyte proliferation. Thus, care must be taken with the TNP-470 compound in combination with other anti-tumoral agents in order to avoid certain unfortunate clinical complications.

Histology and sensitivity to anticancer drugs of two human non-small cell lung carcinomas implanted in the pleural cavity of nude mice

We have established two metastatic models of human non-small cell lung carcinoma (NSCLC)-the NCI-H460 large-cell carcinoma and the A549 adenocarcinoma-by inoculating tumor cells into the pleural space of nude mice. The objectives of this work were as follows: (a) to study the histological characteristics and growth and dissemination patterns of these tumors in nude mice; (b) to assess their sensitivity to drugs that have demonstrated significant clinical therapeutic effect in the treatment of NSCLC; and (c) to investigate the antitumor activity of S 16020-2, a new olivacine derivative, currently in Phase II clinical evaluation. In each of the two models, all animals developed lung tumors, resulting in 100% mortality. Histopathological study showed that these two tumors spread locally to contiguous structures, including the mediastinal pleura and diaphragm, with histological characteristics consistent with the human pathology. Anticancer drugs used for the treatment of NSCLC, such as cisplatin, doxorubicin, vinblastine, and etoposide, enhanced the life span of treated mice in the two models and were more active in the NCI-H460 than in the A549 model. The increases of survival time as compared to control groups were from 60 (P < or = 0.05) to 83% (P < or = 0.01) and from 21 to 40% for NCI-H460 and A549, respectively. Vinorelbine, paclitaxel, and irinotecan showed similar activities in the two models and increased the survival of treated mice by between 38 and 79% (P < or = 0.001) and between 58 (P < or = 0.01) and 78% in the NCI-H460 and A549 models, respectively. However, none of these drugs was curative, reflecting the resistance of this disease to chemotherapy. S 16020-2 exhibited a remarkable antitumor activity, increasing the survival by 82% (P < or = 0.01) for NCI-H460 and by 126% (P < or = 0.001) for A549. This drug was among the most active compounds in these models, thereby indicating its potential for the chemotherapy of this disease.

Biological and pharmacological characterisation of three models of human ovarian carcinoma established in nude mice: use of the CA125 tumour marker to predict antitumour activity

In an attempt to improve the relevance of human tumour xenografts to the clinical situation, we have established 3 models of human ovarian carcinoma (IGROV1, A2780 and NIH:OVCAR-3) in nude mice in which progressive peritoneal carcinomatosis resulted in the death of tumour-bearing animals (median survival times: 32, 40 and 64 days, respectively). Histological analyses revealed both common and different characteristics in growth patterns and dissemination profiles. In each case, three stages of the disease were defined (early, intermediate and late). The antitumour activities of adriamycin, cisplatin, cyclophosphamide and paclitaxel were then compared when administered at the early stage where small multifocal tumour nodules were detectable in the peritoneal cavity of the animals. Significant antitumour activities of cisplatin and particularly paclitaxel were noted in terms of increase in survival time of the treated mice (T/C values for IGROV1, A2780 and NIH:OVCAR-3 respectively: 152%, 167%, and 187% for cisplatin and 211%, 179% and >283% for paclitaxel), paclitaxel being curative against the NIH:OVCAR-3 xenograft. These results reflect the high efficacy of these two drugs in the clinic in the treatment of ovarian carcinoma. The clinically used CA125 tumour marker, not detectable in healthy mice, was measured in the serum of mice bearing IGROV1 and NIH:OVCAR-3 tumours. CA125 serum levels increased as a function of time and were well correlated to disease progression. Moreover, treatment with cisplatin and paclitaxel led to significant decreases in these levels of between 58% and 100%. This human serum marker could be used to predict early on the efficacy of chemotherapy in these two models. In conclusion, the three experimental ovarian carcinomas possess several important characteristics of the human disease and may thus be used as a screen to select new antitumour drugs potentially active in this pathology.

Synthesis and cytotoxic activity of 11-nitro and 11-amino derivatives of acronycine and 6-demethoxyacronycine

Condensation of 2-chloro-3-nitrobenzoic acid with either 5-amino-7-methoxy-2,2-dimethyl-2H-chromene or 5-amino-2,2-dimethyl-2H-chromene afforded diphenylamines 14 and 15. Trifluoroacetic anhydride mediated cyclization gave the corresponding acridones 16 and 17, which were subsequently N-methylated and reduced to 11-aminoacronycine and 11-amino-6-demethoxyacronycine. These two amino compounds, which gave stable water soluble salts, were 2- to 3-fold more potent than acronycine or 6-demethoxyacronycine in inhibiting L1210 cell proliferation.

Semisynthesis and cytotoxicity of styryl-lactone derivatives

The cytotoxicity and the cell-cycle action of altholactone (1), goniofufurone (2), and eight altholactone derivatives (5-12), were determined in vitro on L-1210 cells. Semisyntheses and structure-activity relationships of these compounds are described. The results of this study suggest that the cytotoxicity of altholactone (1), 11-nitro-altholactone (8), and 7-chloro-6,7-dihydroaltholactone (10) is due to the accumulation of the cells in the G2 + M phase of the cell cycle.

Synthesis of 9-O-substituted derivatives of 9-hydroxy-5, 6-dimethyl-6H-pyrido[4,3-b]carbazole-1-carboxylic acid (2-(dimethylamino)ethyl)amide and their 10- and 11-methyl analogues with improved antitumor activity

Analogues of the antitumor drug S 16020-2 modified at the 9, 10, or 11 position were synthesized and evaluated in vitro and in vivo on the P388 leukemia and B16 melanoma models. Starting from 9-methoxy-5, 11-dimethyl-6H-pyrido[4,3-b]carbazole-1-carboxylic acid ethyl ester, the 11-CH3 analogue of 9-hydroxy-5,6-dimethyl-6H-pyrido[4, 3-b]carbazole-1-carboxylic (2-(dimethylamino)ethyl)amide (1), compound 4, was synthesized using a four-step sequence, whereas its 10-CH3 analogue 5 was prepared using a two-step pathway, starting from compound 1. Finally starting from the 9-OH compounds 1, 4, and 5, a series of variously 9-O-substituted derivatives were synthesized. In these series, the most active compounds resulted from esterification of the 9-OH group with various aliphatic diacids, which led to 9-O-CO-( )-COOH derivatives of 1, 4, and 5. For these compounds, the number of long-term surviving mice obtained at the optimal dose were 60-100% in the ip/iv P388 leukemia and 10-35% in the ip/ip B16 melanoma, corresponding to an improved therapeutic index with respect to 1 and 4. This high antitumor activity, with curative examples in both models, was not due to a higher cytotoxicity since these compounds were equally or slightly less potent in vitro than 1 and 4. The most active compounds were thus selected for further in vivo evaluation.

Synthesis and cytotoxic activity of 1-alkoxy- and 1-amino-2-hydroxy-1,2-dihydroacronycine derivatives

Sixteen new derivatives of the natural alkaloid acronycine, bearing 1-alkoxy or 1-amino and 2-hydroxy groups, were synthesized in order to clarify the role of the C-1 substitution. Studies on the cytotoxic activity of compounds 4-19 were carried out in vitro on L-1210 cells. Structure-activity relationships are discussed.

Chiral dihydroxylation of acronycine: absolute configuration of natural cis-1,2-dihydroxy-1,2-dihydroacronycine and cytotoxicity of (1R,2R)- and (1S,2S)-1,2-diacetoxy-1,2-dihydroacronycine

Sharpless asymmetric dihydroxylation of acronycine (1) gave (1R, 2R)-1,2-dihydroxy-1,2-dihydroacronycine (2) and (1S,2S)-1, 2-dihydroxy-1,2-dihydroacronycine (3), which allowed determination of the absolute configuration of natural cis-1,2-dihydroxy-1, 2-dihydroacronycine as 1R,2R. The cis isomer had been previously isolated from various Sarcomelicope species. Benzylic reduction of isomers 2 and 3 gave the alcohols 4 (2R) and 5 (2S), respectively. Acetylation of 2 and 3 afforded the corresponding esters 6 and 7. No significant difference of cytotoxicity was observed between these (1R,2R)- and (1S,2S)-enantiomers and the recently described, highly active racemic cis-1,2-diacetoxy-1,2-dihydroacronycine, when tested against L-1210 cells in vitro.

Mechanisms of tumor angiogenesis and therapeutic implications: angiogenesis inhibitors

Angiogenesis is the development of new blood vessels from the existing vascular bed. In normal conditions this tightly regulated process occurs only during embryonic development, the female reproductive cycle and wound repair. In contrast, in pathological conditions such as malignant growth, atherosclerosis and diabetic retinopathy, angiogenesis becomes persistent due to an imbalance in the interplay between the positive and negative regulatory signals controlling the process. Thus, the control of tumor neovascularization may lead to new therapeutic approaches. Indeed, several anti-angiogenic drugs are currently undergoing preclinical characterization and/or clinical investigation. Recent achievement has clarified the mechanisms of action leading to pathological angiogenesis and has highlighted the role of hypoxia, growth factors, growth factor-receptors, enzymes and cell adhesion molecules involved in the process. This knowledge has permitted the design of receptor antagonists, adhesion molecule blockers and new targeted vascular approaches including gene therapy.

Setting up of an original computer-assisted methodology to characterize in vitro drug-induced anti-angiogenic effects

The development of angiogenesis within a tumor brings on a sequence of extremely complex molecular events. We have developed a methodology which enables a wide set of biological parameters to be quantitatively determined in the field of anti-angiogenesis pharmacology. This methodology which includes a video cell tracking device, is unique because it offers the possibility of evaluating the specific influence of a given compound with potential anti-angiogenic properties on cell cycle kinetics, cell death, global cell line growth, and cell motility. We chose TNP-470, a synthetic analogue of fumagilin, to test our methodology on HUVEC cell lines taken from various human umbilical cord veins. The experiments carried out with TNP-470 did not confirm all the data reported in the literature. Our results show that i) TNP-470 could be considered as a cytotoxic agent; ii) this compound had an apparently marginal cytostatic effect; and iii) it did not increase the apoptosis level. Our methodology also revealed that the HUVEC cell lines are very heterogeneous in terms of different biological parameters. This highlights the problem of the reproductibility of the result.

Circumvention of P-glycoprotein-mediated multidrug resistance by S16020-2: kinetics of uptake and efflux in sensitive and resistant cell lines

PURPOSE

In contrast to Adriamycin (ADR), the novel olivacine derivative S16020-2 has demonstrated potent antitumor activity in vitro and in vivo against cell lines displaying the P-glycoprotein (Pgp)-mediated multidrug-resistance phenotype (MDR), suggesting that this compound is not transported by Pgp. The purpose of this work was to study the accumulation of S16020-2 in Pgp-overexpressing cells.

METHODS

The kinetics of accumulation and retention of radiolabeled S16020-2 and ADR in sensitive KB-3-1, P388, and S1 cells and their resistant counterparts KB-A1, P388/VCR-20, and S1/tMDR cells were investigated.

RESULTS

The rates of efflux of S16020-2 and ADR were similar and were higher in KB-A1 cells than in KB-3-1 cells. A modulator of MDR, S9788, inhibited the efflux of both compounds only in KB-A1 cells. These results demonstrate that S16020-2 is effectively transported by Pgp overexpressed by KB-A1 cells with an efficiency close to that of ADR. A similar conclusion was obtained with the P388/VCR-20 cell line. In addition, the initial rate of uptake and the accumulation of S16020-2 were markedly higher than those of ADR in the cell lines tested.

CONCLUSIONS

The cytotoxic potency of S16020-2 toward tumor cells overexpressing Pgp is thus likely to be due to its rapid rate of uptake, which bypasses Pgp and thus leads to a high cellular accumulation.

Synthesis and antiproliferative activity of a cyclic analog of dolastatin 10

A cyclic analog of the natural antiproliferative compound dolastatin 10 was synthesized by introducing an ester link between the N- and C-terminal residues which were modified accordingly. The final macrolactonization was performed by using isopropenyl chloroformate and DMAP as reagents. This analog exhibits submicromolar antiproliferative activity against the L1210 and HT29 cell lines and inhibits in vitro tubulin polymerization (IC50, 39 microM).

Synthesis and cytotoxic activity of pyranocoumarins of the seselin and xanthyletin series

The synthesis of known (3-6) and new (7-10 and 14-22) coumarins in the seselin and xanthyletin series is described. The cytotoxic activity of compounds 3-22 was carried out in vitro on L-1210 cells. The most active compounds were 9, 16, 18, and 20 in the seselin series and 10, 17, and 19 in the xanthyletin series. Structure-activity relationships are discussed.

A zinc chelator inhibiting gelatinases exerts potent in vitro anti-invasive effects

Matrix metalloproteinases are zinc metalloenzymes involved in remodelling of the extracellular matrix. We compared the anti-invasive properties of a zinc ejector matrix metalloproteinase inhibitor with those of reference compounds (hydroxamic acid-based BB-94 and Ro-31-9790) which form inactive ternary complexes with the enzymes and the catalytic zinc. We show that the compound undecadenedioic acid bis-[[2-(3 H-imidazol-4-yl)-ethyl]-amide] (S 30372) is active against gelatinases, chelates zinc and exhibits enzymatic features compatible with the potential to extract zinc from gelatinases. We then used five invasive cell lines in the Matrigel invasion chamber assay (NIH-3T3 fibroblasts, Lewis lung carcinoma cells, EJ138 and J82 bladder carcinoma and HT1080 fibrosarcoma cells). With the exception of J82 cells which were unaffected by the three inhibitors, all remaining cells were substantially more sensitive to S 30372 in terms of maximal inhibition of invasion attained. This suggests that matrix metalloproteinase inhibitors with zinc chelating/ejecting properties may be more efficient in preventing tumor progression.

Synthesis, properties and biological evaluation of substituted furo[3,2-e] and pyrano[3,2-e]pyrido[4,3-b]indoles

Furo[3,2-e]- and pyrano[3,2-e]pyrido[4,3-b] indoles were synthesized from 1,4,5-trisubstituted 8-hydroxy-5H-pyrido[4,3-b]indoles. The intermediates, 10-chloro-6H-furo[3,2-e]pyrido[4,3-b]indole (11), 10-chloro-2,6-dihydro-1H-furo[3,2-e]pyrido-[4,3-b]indole (10) and 11-chloro-2,3-dihydro-3H,7H-pyrano[3,2-e]pyrido[4,3-b]indole (15), were substituted by diamines under thermal conditions (180 degrees C). In contrast, 11-chloro-3H,7H-pyrano[3,2-e]pyrido[4,3-b]indole (14), 9-allyl-1-chloro-4,5-dimethyl-5H-pyrido[4,3-b]indole (9a) and 8-propargyloxy-4,5-dimethyl-5H-pyrido[4,3-b]indole (8) led mainly to 1-aminosubstituted 8-hydroxy-5H-pyrido[4,3-b]indole derivatives resulting from an unexpected C3 unit elimination. When examined in three tumour cell lines (L1210 leukaemia, the B16 melanoma and the MCF7 breast adenocarcinoma) the new amino substituted furo[3,2-e]-, dihydrofuro[3,2-e]- and dihydropyrano[3,2-e]-pyrido[4,3-b]indole derivatives revealed cytotoxic properties, especially important for the 2,6-dihydro-1H-furo[3,2-e]pyrido[4,3-b]indole series. The most active compound (12b) significantly inhibits both DNA topoisomerases I and II, and is as potent as Adriamycin at inhibiting cell proliferation and inducing a massive accumulation of L1210 cells in the G2 + M phase of the cell cycle. However, 12b was less active than Adriamycin when tested in vivo against P388 leukaemia or the B16 melanoma tumour models.

1-Amino-substituted 8-hydroxy-4,5-dimethyl-5H-pyrido[4,3-b]indoles with propyl- or methyl substituents at the 9-, and 7,9-positions: synthesis and biological evaluation

The title compounds were synthesized in 9-10 steps in order to compare their cytotoxic properties to that for 1-(3-dimethylaminopropyl)-amino-4,5-dimethyl- 8-hydroxy-5H-pyrido[4,3-b]indole. Whereas the latter is a potent cytotoxic agent, displaying significant antitumour activity, the corresponding 9-propyl (and 7,9-dimethyl) derivatives were found to be > 10-fold less cytotoxic.

Synthesis and biological activity of chimeric structures derived from the cytotoxic natural compounds dolastatin 10 and dolastatin 15

The natural cytotoxic compounds dolastatins 10 and 15 exhibit great similarities in structure and in their biological activity profiles. Two compounds (1 and 2) formed by interchanging the dolaisoleuine residue of dolastatin 10 and the MeVal-Pro dipeptide of dolastatin 15 were synthesized in order to evaluate the possible equivalence of these units. These compounds can be considered as chimeras of dolastatins 10 and 15 formed by the N-terminal part of the former and the C-terminal part of the latter and vice versa. Both analogues exhibited a marked decrease in their cytotoxic activity but showed similar differential cytotoxicity with regard to the cell lines assayed compared with the parent compounds. HT-29 cell line was the least sensitive one. However, this activity was in the nanomolar level and close to that of vincristine. The differences in their effect on tubulin polymerization were less pronounced. We confirmed the already known crucial role of the Dil residue in this assay. The nonequivalence of the Dil unit and the MeVal-Pro dipeptide probably reflects modification in the relative positions of the N-dimethylamino and the phenyl moieties.

Antimalarial and cytotoxic potential of four quassinoids from Hannoa chlorantha and Hannoa klaineana, and their structure-activity relationships

Hannoa chlorantha and Hannoa klaineana (Simaroubaceae) are used in traditional medicine of Central African countries against fevers and malaria. Four stem bark extracts from H. klaineana and four quassinoids from H. chlorantha were examined in vitro against Plasmodium falciparum NF 54. The extracts displayed good activities, while the quassinoids were highly active, with IC50 values well below 1 microgram ml-1, those of chaparrinone and 15-desacetylundulatone being much lower than 0.1 microgram ml-1 (0.037 and 0.047 microgram ml-1, respectively). Chaparrinone is five times more active than 14-hydroxychaparrinone against P. falciparum, indicating that the hydroxyl function at C-14 is unfavourable for antiplasmodial activity. As 14-hydroxychaparrinone has a seven-times higher cytotoxic activity against P-388 cells than chaparrinone, the latter compound has the better antiplasmodial therapeutic index. All four quassinoids were evaluated in vivo in a standard 4-day test as well. 15-Desacetylundulatone was proven to be the most active compound, almost totally suppressing the parasitaemias of OF1 mice for at least 7 days, while both chaparrinone and 14-hydroxychaparrinone were active for at least 4 days. Quassinoids have ED50 values much lower than 50 mg kg-1 body weight day-1 and none of them caused obvious side effects. The keto function at C-2 in 15-desacetylundulatone is apparently of crucial importance for its high activity. 6-alpha-Tigloyloxyglaucarubol was not active at all. Chaparrinone is considered the most interesting of the investigated quassinoids and its in-vivo antimalarial potential will be examined further.

Synthesis and biological activity of esters in the trans-1,2-dihydroxy-1,2-dihydroacronycine series

Permanganate oxidation of acronycine (1) led to keto alcohol 4 which could be reduced to trans-1,2-dihydroxy-1,2-dihydroacronycine (3) using NaBH4. Acylation of 3 afforded 12, 13, and 14. These esters (12, 13, and 14) were more potent than 1 when tested against L-1210 cells in vitro. Diacetate 12 was evaluated in vivo against murine P-388 leukemia and was markedly active at a dose 16-fold lower than acronycine itself. Comparison of these results with those recently obtained in the cis-1,2-dihydroxy-1,2-dihydroacronycine series is discussed.