Olga Bruno

GEBR-7b, a novel PDE4D selective inhibitor that improves memory in rodents at non-emetic doses.

BACKGROUND AND PURPOSE Strategies designed to enhance cerebral cAMP have been proposed as symptomatic treatments to counteract cognitive deficits. However, pharmacological therapies aimed at reducing PDE4, the main class of cAMP catabolizing enzymes in the brain, produce severe emetic side effects. We have recently synthesized a 3‐cyclopentyloxy‐4‐methoxybenzaldehyde derivative, structurally related to rolipram, and endowed with selective PDE4D inhibitory activity. The aim of the present study was to investigate the effect of the new drug, namely GEBR‐7b, on memory performance, nausea, hippocampal cAMP and amyloid‐β (Aβ) levels.

Structure-based optimization of pyrazolo[3,4-d]pyrimidines as Abl inhibitors and antiproliferative agents toward human leukemia cell lines.

Results from molecular docking calculations and Grid mapping laid the foundations for a structure-based optimization approach to improve the biological properties of pyrazolo-pyrimidine derivatives in terms of inhibition of Abl enzymatic activity and antiproliferative properties toward human leukemia cells. Insertion of halogen substituents with various substitution patterns, suggested by simulations, led to a significant improvement of leukemia cell growth inhibition and to an increase up to 1 order of magnitude of the affinity toward Abl.

Progress in 5H[1]benzopyrano[4,3-d]pyrimidin-5-amine series: 2-methoxy derivatives effective as antiplatelet agents with analgesic activity

A series of 2-methoxy-5H[1]benzopyrano[4,3-d]pyrimidin-5-amines were prepared and screened for their in vitro antiplatelet activity inducing the aggregation by ADP, arachidonic acid (AA) and collagen. In vivo experiments were performed in order to evaluate their antiphlogistic, analgesic and antipyretic activities. Title compounds showed antiplatelet activity in aggregation AA or collagen-induced, and a good analgesic activity without any gastric toxicity. Comparison with a number of analogue benzopyrano[4,3-d]pyrimidine derivatives and some SAR consideration were reported.

Synthesis, biological evaluation and docking studies of 4-amino substituted 1H-pyrazolo[3,4-d]pyrimidines.

The synthesis of new 4-amino substituted pyrazolo[3,4-d]pyrimidines along with their activity in cell-free enzymatic assays on Src and Abl tyrosine kinases is reported. Some compounds emerged as good dual inhibitors of the two enzymes, showed antiproliferative effects on two Bcr-Abl positive leukemia cell lines K-562 and KU-812, and induced apoptosis, as demonstrated by the PARP assay. Docking studies have been also performed to analyze the binding mode of compounds under study and to identify the structural determinants of their interaction with both Src and Abl.

3-Arylsulphonyl-5-arylamino-1,3,4-thiadiazol-2(3H)ones as Anti-inflammatory and Analgesic Agents

Two series of 3-arylsulphonyl-5-arylamino-1,3,4-thiadiazol-2(3H)ones 2 with potential anti-inflammatory and analgesic activity were prepared and tested. Pharmacological results revealed that all the title compounds, endowed with an arylsulphonyl side chain, possess good antalgic activity and fair anti-inflammatory properties. The analgesic profile of the two series, evaluated by the acetic acid writhing test, showed that compounds 2c, 2f and 2h, in particular, were the most active. Structure-activity relationships are briefly discussed.

Improvement of spatial memory function in APPswe/PS1dE9 mice after chronic inhibition of phosphodiesterase type 4D

Phosphodiesterase type 4 inhibitors (PDE4-Is) have received increasing attention as cognition-enhancers and putative treatment strategies for Alzheimers disease (AD). By preventing cAMP breakdown, PDE4-Is can enhance intracellular signal transduction and increase the phosphorylation of cAMP response element-binding protein (CREB) and transcription of proteins related to synaptic plasticity and associated memory formation. Unfortunately, clinical development of PDE4-Is has been seriously hampered by emetic side effects. The new isoform-specific PDE4D-I, GEBR-7b, has shown to have beneficial effects on memory at non-emetic doses. The aim of the current study was to investigate chronic cognition-enhancing effects of GEBR-7b in a mouse model of AD. To this extent, 5-month-old (5M) APPswe/PS1dE9 mice received daily subcutaneous injections with GEBR-7b (0.001 mg/kg) or vehicle for a period of 3 weeks, and were tested on affective and cognitive behavior at 7M. We demonstrated a cognition-enhancing potential in APPswe/PS1dE9 mice as their spatial memory function at 7M in the object location test was improved by prior GEBR-7b treatment. APPswe/PS1dE9 mice displayed lower levels of CREB phosphorylation, which remained unaltered after chronic GEBR-7b treatment, and higher levels of tau in the hippocampus. Hippocampal brain-derived neurotrophic factor levels and synaptic densities were not different between experimental groups and no effects were observed on hippocampal GSK3β and tau phosphorylation or Aβ levels. In conclusion, GEBR-7b can enhance spatial memory function in the APPswe/PS1dE9 mouse model of AD. Although the underlying mechanisms of its cognition-enhancing potential remain to be elucidated, PDE4D inhibition appears an interesting novel therapeutic option for cognitive deficits in AD.

New polycyclic pyrimidine derivatives with antiplatelet in vitro activity: synthesis and pharmacological screening.

The preparation and the pharmacological screening of novel anti-aggregatory/antiphlogistic polycyclic pyrimidine derivatives are described. The compounds were developed starting from bioactive 2-aminobenzopyranopyrimidine derivatives in order to assess the importance of the benzopyrano[4,3-d]pyrimidine structure and the role of an amino basic moiety in position 2. Antiplatelet activity was assessed in vitro against ADP and arachidonic acid-induced aggregation in guinea-pig plasma. Anti-inflammatory/analgesic/antipyretic activities were studied in rat paw oedema, mouse writhing test and E. coli-induced rat fever. Ulcerogenic and gastroprotective effects were also investigated in vivo on rat gastric mucosa. Among the tested compounds, the 5-substituted benzopyranopyrimidine derivatives 3d and 4d proved to be the most active antiplatelet agents as potent as acetylsalicylic acid against arachidonic acid-stimulated aggregation. Furthermore the 2-methylthio derivative 4d was endowed with greater efficacy against ADP aggregation suggesting that additional non-TXA2 dependent mechanisms are involved in its biological activity. Orally administered at 100 mg kg(-1) in rats this latter compound displayed antiphlogistic acitivity comparable to indomethacin (10 mg kg(-1)) coupled with an unusual gastroprotective effect on ethanol-induced ulcers. In conclusion, these findings indicate that the 5-pyrrolidino-2-methylthiobenzopyrano[4,3-d]pyrimidine 4d fulfils the chemical requirements to exhibit antiplatelet activity associated with gastroprotective effect.

Antiinflammatory agents: new series of N-substituted amino acids with complex pyrimidine structures endowed with antiphlogistic activity

A series of N-methyl-N-pyrimidin-2-yl glycines 2a-e, having the pyrimidine ring fused with a cyclohexane [N-methyl-N-(5,6,7,8-tetrahydroquinazolin-2-yl)glycine], cyclohexene [N-methyl-N-(5,6-dihydroquinazolin-2-yl)glycine], 1,2,3,4-tetrahydronaphthalene [N-methyl-N-(5,6-dihydrobenzo[e]quinazolin-2-yl)glycine], benzopyrane [N-methyl-N-(5-phenyl-5H-[1]benzopyrano[4,3-d]pyrimidin-2-yl)glyci ne] and benzothiopyrane [N-methyl-N-(5H-[1]benzothiopyrano[4,3-d]pyrimidin-2-yl)glycine] ring, was prepared and tested for antiinflammatory activity. With the same purpose a number of N-5H-[1]benzopyrano[4,3-d]pyrimidin-2-yl substituted amino acids 3a-e, having a different chain length and branching were also synthesized and tested. All the described products 2 and 3 showed an appreciable antiphlogistic activity, particularly 2b and 2c.

New insights into small-molecule inhibitors of Bcr-Abl

Chronic myelogenous leukemia (CML) is a myeloproliferative disease associated with a defined genetic abnormality, the Bcr‐Abl fusion gene on the Philadelphia chromosome that expresses the constitutively activated tyrosine kinase (TK) Bcr‐Abl. This enzyme leads to the malignant transformation of primitive hematopoietic cells and to the consequent disease. The central role of Bcr‐Abl in the pathogenesis of CML culminated in the discovery of imatinib (an ATP‐competitive inhibitor), which is currently the frontline therapy for CML. Unfortunately, the initial enthusiasm generated by its high response rate has been dampened by the development of resistance, especially in the advanced phases of CML. To overcome imatinib resistance, several second‐generation ATP‐competitive inhibitors endowed with increased potency against imatinib‐resistant mutants have been developed: the dual Src/Abl inhibitor dasatinib and the Abl inhibitor nilotinib have been recently approved by US‐FDA for the treatment of imatinib‐resistant CML, and many other compounds are currently in clinical trial. Although second‐generation TK inhibitors have shown to be clinically effective against most of the imatinib‐resistant mutants, to date poor results have been obtained in the treatment of the Bcr‐Abl T315I mutant. In this review we will report the most interesting second‐generation Abl and dual Src/Abl inhibitors recently entered in clinical trial, but also the new ATP‐competitive and uncompetitive inhibitors published in the last few years, focusing on their chemical structure, mechanism of action, and structure–activity relationship.  © 2009 Wiley Periodicals, Inc. Med Res Rev, 31, No. 1, 1–41, 2010

Synthesis of N-substituted-N-acylthioureas of 4-substituted piperazines endowed with local anaesthetic, antihyperlipidemic, antiproliferative activities and antiarrythmic, analgesic, antiaggregating actions.

Three series of N-acyl and N-cyclohexyl- or N-methyl or N-phenyl-thioureas of 4-substituted (methyl, phenyl, 2-pyridyl)piperazines (4-12) were synthesised according to a highly convergent one-pot procedure and tested in vivo (local anaesthetic, anti-hyperlipoproteinemic, analgesic, anti-inflammatory, antiarrythmic activities) and in vitro (antiaggregating and, for some selected derivatives, antiproliferative activities) experiments. All the test compounds showed local anaesthesia in particular 4Ar(4), 5Ar(4), 12Ar(3) (after 5 min) and 5Ar(2), 5Ar(3), 9Ar(4) (after 30 min) were equipotent to lidocaine. In lowering triglyceride levels, compounds 6Ar(4) and 7Ar(3) were more active than nicotinic acid, whereas 7Ar(4) and 11Ar(4) were approximately equipotent. As concerns analgesic activity, 5Ar(2) and 5Ar(4) were as active as indomethacin. Appreciable anti-inflammatory activity was found in 8Ar(1), 5Ar(2) and 11Ar(2), but inferior to that of indomethacin. High levels of antiarrythmic activity, comparable with that of quinidine, were found in derivatives 4Ar(2) and 10Ar(1). Compounds 4Ar(2) and 8Ar(2), assayed in antitumor in vitro screening system at National Cancer Institute (NCI), showed significant antiproliferative activity against ACHN cell line (GI50: 0.13 microM) and NCI-H226 cell line (GI50: 1.03 microM), respectively.