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.

Detection of influenza A(H1N1)pdm09 virus in a patient travelling from Shanghai to Italy in July 2018: an uncommon clinical presentation in a non-seasonal period.

Influenza is one of the most common infectious diseases in travellers, especially in those returning from subtropical and tropical regions. In late June 2018 an influenza A(H1N1)pdm09 virus infection was diagnosed in a 36-years-old man, returned from a travel in Shanghai and hospitalized at the Ospedale Policlinico San Martino, Genoa, Italy, with a diagnosis of fever and an uncommon clinical presentation characterised by a persistent leukopenia. Phylogenetic analysis revealed a closeness with influenza A(H1N1)pdm09 strains circulating in the US in May-June 2018. Prompt recognition of influenza infection led to a proper case management, demonstrating the crucial role of the continuous influenza surveillance programme.

Cytotoxic effects of a novel pyrazolopyrimidine derivative entrapped in liposomes in anaplastic thyroid cancer cells in vitro and in xenograft tumors in vivo.

In this study, we evaluated the activity of two novel pyrazolopyrimidine derivatives (Si 34 and Si 35) against ARO cells, a human anaplastic thyroid cancer cell line. ARO cells exposed to different concentrations of the drugs showed a reduced growth rate and an increase of mortality. After 72 h incubation, doses of 5 and 10 microM Si 34 determined a decrease of cell counts by approximately 25% and approximately 75% compared with those of control cells respectively. Similar findings were observed using Si 35. Treatment with both Si 34 and Si 35 at 10 microM increased cell mortality also ( approximately 29% and approximately 18% respectively). At these concentrations, a decrease in cyclin D1 levels was observed. To improve the biopharmaceutical properties, a liposome formulation was prepared. When entrapped in unilamellar liposomes, Si 34 exerted its cytotoxic effects even at lower doses (maximal inhibition at 5 microM) and after shorter incubation time (48 h) either in ARO or other thyroid cancer cell lines. The effects were associated with weak apoptotic death. Inhibition of epidermal growth factor-stimulated src and ERK phosphorylation, as well as reduction of migration properties of ARO cells was also observed. Moreover, the growth of tumor xenografts induced in severe combined immunodeficiency (SCID) mice was inhibited by i.v. administration of 25-50 mg/kg of the drug liposomal formulation. In conclusion, the liposomal preparation of this novel pyrazolopyrimidine derivative appears to be a promising tool for the treatment of anaplasic thyroid cancer.

Small molecules ATP-competitive inhibitors of FLT3: a chemical overview.

FLT3 is a tyrosine kinase (TK), member of the class III TK receptor family, normally expressed in hematopoietic, immune and neural systems, also playing an important role in the pathogenesis of acute leukemias, particularly acute myeloid leukemia (AML), where it is present in constitutively activated mutated forms, correlated with poor prognosis, in a notable percentage of patients. For these reasons FLT3 soon appeared as a promising target for the therapeutic intervention for this severe and aggressive malignancy; the recent determination of the crystal structure of the autoinhibited form of FLT3 gave new trend for the design and the synthesis of potent inhibitors. Small molecules tyrosine kinase inhibitors represent one of the largest drug family currently targeted by pharmaceutical companies for the treatment of cancer. Exciting examples of such molecules have reached advanced clinical trials and have been recently approved by FDA for the treatment of different solid or haematological tumors. Usually TK inhibitors share common features, namely two hydrophobic/aromatic regions bearing one or more hydrogen bonding substituents. These two regions can be connected by different spacers and almost all the molecules contain a component resembling the ATP purine structure. This review will deal with FLT3 synthetic inhibitors, reporting not only the most important molecules that are in clinical trials, but also the new compounds that have appeared in literature in the last few years. Our attention will be focused on chemical structures, mechanisms of action and structure-activity relationships.

Antiangiogenic agents: an update on small molecule VEGFR inhibitors.

Angiogenesis is a tightly regulated process that leads to the formation of new blood vessels sprouting from pre-existing microvasculature and occurs in limited physiological conditions or under pathological situations such as retinopathies, arthritis, endometriosis and cancer. Blockade of angiogenesis is an attractive approach for the treatment of such diseases. Particularly in malignancies, antiangiogenic therapy should be less toxic in comparison with conventional treatments such as chemotherapy, as angiogenesis is a process relatively restricted to the growing tumor. Vascular endothelial growth factor (VEGF) is one of the most important inducers of angiogenesis and exerts its cellular effects mainly by interacting with two high-affinity transmembrane tyrosine kinase receptors: VEGFR-1 (Flt-1) and VEGFR-2 (KDR/Flk-1). It has been proven that inhibition of VEGF receptor activity reduces angiogenesis. For these reasons, the inhibition of VEGF or its receptor signalling system is an attractive target for therapeutic intervention. The most studied and developed inhibitors are monoclonal antibodies that neutralize VEGF, ribozymes, and small molecule VEGFR kinase inhibitors. Many important reviews dealing with VEGF-induced angiogenesis and its inhibition through the block of VEGF receptors have been reported, especially from a biological point of view. Here, we will review small synthetic VEGFR inhibitors that have appeared in literature in the last few years, focusing our attention on their medicinal chemistry in terms of chemical structure, mechanisms of action and structure-activity relationships. In fact, there have been an increased number of tyrosine kinase inhibitors in the most recent literature reports; their biological profile is extremely interesting and could be of great importance to medicinal chemists working in this area in improving their efficacy.

Last findings on dual inhibitors of abl and SRC tyrosine-kinases.

Chronic myelogenous leukemia (CML) is a myeloproliferative disease characterized by the presence of the Philadelphia chromosome that expresses the constitutively activated tyrosine kinase Bcr-Abl; this enzyme causes hyperproliferation of the stem cells and the consequent pathology of the disease. Targeted inhibitors of Bcr-Abl have antiproliferative effects on the leukemic cells and induce apoptosis, favouring a regression of the CML chronic phase, but in the successive blast crisis phase cancer cells frequently develop resistance to Bcr-Abl inhibitors. Src is a family of non-receptor tyrosine kinases, fundamental for cell development, growth, replication, adhesion, motility and is overexpressed in a wide number of human cancers. Recently it was demonstrated that Src is increased in hematopoietic cells expressing Bcr-Abl and is involved in the oncogenic pathway that causes CML. For this reason and also for the development of resistance to classical Bcr-Abl inhibitors, various dual Src/Abl inhibitors have been recently synthesized and tested. This mini review will be focused on the latest finding on this matter.

Growth inhibition of medullary thyroid carcinoma cells by pyrazolo-pyrimidine derivates.

There is no effective treatment for recurrent or metastatic medullary thyroid carcinoma (MTC), a tumor arising from thyroid C-cells commonly presenting an inherited or acquired RET mutation. In this study we examined the sensitivity of two human MTC cell lines to novel pyrazolopyrimidine derivates, able to inhibit src-family tyrosine kinase activity. In TT cells [carrying the multiple endocrine neoplasia (MEN)2A Ret mutation Cys 634Trp] and MZ-CRC-1 cells (carrying the MEN2B RET mutation Met891Thr), one of these compounds, namely Si 34, determined a significant growth inhibitory effect (approximately 90% vs control for TT, 80% vs control for MZ-CRC-1) mainly due to enhanced cell mortality after a 6-day incubation. At concentrations that increased cell mortality, neither biochemical or morphological characteristics of apoptosis were detected in TT and MZCRC- 1 cells treated with Si 34. These results, when confirmed in other in vivo preclinical models, suggest that this novel tyrosine kinase inhibitor may be useful for the treatment of MTC.

2-Amino/azido/hydrazino-5-alkoxy-5H-[1]benzopyrano[4,3-d]pyrimidines: synthesis and pharmacological evaluation.

New series of 5-alkoxy-benzopyranopyrimidine derivatives were developed from the chemical modulation of the substituent in position 2 of the scaffold, with the aim to produce analgesic/antiphlogistic agents more potent than analogues previously reported. The 2-hydrazino derivatives exhibited a good analgesic activity in writhing test; the analgesic doses of the compounds did not affect mice spontaneous locomotor activity thus any confounding sedative effect could be excluded. These derivatives revealed an aspirin-like profile with a strong inhibition of AA-induced platelet aggregation, probably due to a strong, non selective, inhibition of cyclooxygenases. In spite of the inhibition of COX activity displayed in vitro, the compounds did not cause gastric damage in rats after acute oral administration. A different pharmacological profile was observed for the 2-azido derivatives, particularly in vivo.

Click chemistry, a potent tool in medicinal sciences.

This review focuses on the application of click chemistry in medicinal sciences, and particularly on its role in drug discovery. Because of its high modularity, click chemistry helps to accelerate the current drug discovery process, which relies on massive screening of chemical libraries. This article describes examples of click chemistry applications that are aimed at finding new lead candidates against pathologies such as cancer, AIDS and Alzheimer's disease, and explores the impact that the technique could have in therapy and prevention in the near future, through application in drug delivery systems, bioconjugation and diagnostic. An introduction, addressed to researchers who intend to use this methodology, examines the opportunities to perform click reactions according to the most common and best studied techniques, such as synthesis in water, on solid phase, and under microwave or ultrasound irradiation. Every topic is furnished with examples which have appeared in the literature in the last five years and is clarified by schemes and figures.

Hck inhibitors as potential therapeutic agents in cancer and HIV infection.

Hematopoietic cell kinase (Hck) is a member of the Src-family of non-receptor tyrosine kinases, which plays many roles in signalling pathways involved in the regulation of cell processes. Hck is expressed in cells of hematopoietic origin, specifically myelomonocytic cells and B lymphocytes. It participates in phagocytosis, adhesion, migration, regulation of protrusion formation on cell membrane, lysosome exocytosis, podosome formation and actin polymerization. More importantly from a medicinal chemistry point of view, high levels of Hck are involved in chronic myeloid leukemia and other hematologic tumors. Furthermore, Hck activity has been associated with virus infections including HIV-1. In particular, Hck is activated by the HIV-1 accessory protein Nef, a multifunctional HIV-1 protein that accelerates progression to AIDS and enhances the infectivity of progeny viruses. Nef binding to Hck leads to kinase activation which is important in AIDS pathogenesis. For these reasons, Hck represents a potentially good therapeutic target for the treatment of both specific cancers and HIV infection. This article summarizes Hck biological activities connected with malignancies and HIV infection, many of which have been only recently reported, and presents an overview of the compounds endowed with Hck inhibitory activity, especially focusing on the medicinal chemistry aspect.

O-[2-hydroxy-3-(dialkylamino)propyl]ethers of (+)-1,7,7-trimethyl bicyclo[2.2.1]heptan-2-one oxime (camphor oxime) with analgesic and antiarrhythmic activities.

A novel series of O-[2-hydroxy-3-(dialkylamino)propyl]ethers of (+)-camphor oxime was prepared and tested for its cardiovascular, analgesic and anti-inflammatory properties. No significant anti-inflammatory and hypotensive activities were displayed by any of the compounds, whereas several of them are reasonably active as antiarrhythmic and analgesic agents.

N-substituted 3-(arylamino)-4,5-dihydro-2H-benz[g]indazol-2-yl acetamides with anti-inflammatory and analgesic activities.

A series of substituted 3-(arylamino)-4,5-dihydro-2H-benz[g]indazol-2-yl acetamides was synthesized and tested in comparison with former analogues. The title compounds showed only weak antiarrhythmic properties but good anti-inflammatory and antinociceptive activity, particularly evident in the morpholino derivative.

Synthesis of 6-thiosubstituted 5-ethoxycarbonyl-1,3-diphenyl-2-thioxo-2,3-dihydropyrimidin-4(1H)-ones, 6-substituted 5-hydroxy-1,3-diphenyl-2,3-dihydrothieno[2,3-d]pyrimidin-4(1H)-ones and their esters with local anesthetic, antiarrhythmic, antiinflammatory and analgesic activities.

The synthesis of 6-thiosubstituted 5-ethoxycarbonyl-1,3-diphenyl-2-thioxo-2,3-dihydropyrimidin- 4(1H)-ones 3, and of 6-substituted 5-hydroxy-1,3-diphenyl-2,3-dihydrothieno[2,3-d]pyrimidin-4(1H)-ones 5 and their esters 6 is described. These derivatives were prepared in order to evaluate the influence on the pharmacological profile of alkyl substituents bearing polar/hydrophilic functionalities at an enethiol substructure as in compounds 3 or to assess the effects arising from the incorporation of the sulfur atom in a thiophene moiety as in thienopyrimidinones 5 and 6 in comparison with a series of 5-substituted 6-acylthio-1,3-diphenyl-2-thioxo-2,3-dihydropyrimidin-4(1H)-ones 1c,d, previously described. Preliminary screenings suggest that all tested compounds maintained or even increased the local anesthetic activity, but failed in the platelet antiaggregating activity; on the other hand, antiarrhythmic and antiinflammatory activity was preserved in some esters 6.

N-arylsubstituted-1-aryl-3,4-diphenyl-5-pyrazole amines with analgesic and antiarrhythmic properties.

A series of N-aryl substituted-1-aryl-3,4-diphenyl-5-pyrazole amines was synthesized and evaluated for antiinflammatory, antihypertensive and platelet antiaggregating activities. Several of them were found to exhibit a significant analgesic and antiarrhythmic activity.

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.

Synthesis and anti-inflammatory activity of esters derived from 5-aryl-1,2-dihydro-2-(2-hydroxyethyl)-3H-1,2,4-triazole-3-thiones.

Some aliphatic and aromatic esters 2a-l were prepared starting from 5-aryl-1,2,4-triazoline-3-thiones bearing a 2-hydroxyethyl chain in position 2. The title compounds were evaluated for antipyretic and anti-inflammatory activities. Nearly all derivatives and in particular 2f, 2h, 2k exhibited antiphlogistic properties but were lacking in antipyretic activity.

Preparation of new 5-aroylamino substituted 3-nicotinoyl/isonicotinoyl-1,3,4-thiadiazol-2(3H)-ones with anti-inflammatory activity.

A series of 1,3,4-thiadiazol-2(3H)-ones (2a-j) with a nicotinoyl/isonicotinoyl group in position 3 and an aroylamino substituent in position 5 of the ring was prepared and evaluated for antipyretic and anti-inflammatory activities. All the title compounds and in particular 2e, 2i and 2j exhibited anti-inflammatory activity and were devoid of antipyretic properties.

N-Acyl-N-phenyl ureas of piperidine and substituted piperidines endowed with anti-inflammatory and anti-proliferative activities.

Six series of N-acyl-N-phenyl ureas 1-6 of piperidine (1), and 2-ethyl- (2), 3-methyl- (3), 4-methyl- (4), 4-phenyl- (5), cis-2,6-dimethyl- (6) piperidine were synthesised and evaluated for their anti-inflammatory, anaesthetic, anti-pyretic properties. Some derivatives of series 1 and 5 were also assayed for anti-proliferative activity. Several compounds showed an anti-inflammatory activity comparable or slighty inferior to that of indomethacin in rats (1c,d, 2a,b,g,h, 3b, 4h, 5d,e). Moreover, an appreciable anti-inflammatory activity was also found in 2c,e, 3e,f,g, 4g, 5a,b,c,f,h, and 6a,b,d. All the compounds were devoid of anti-pyretic activity and only a few of them exhibited a low level of infiltration anaesthesia in mice. Compound 5a showed a broad spectrum anti-cancer activity (at low micromolar concentrations), particulary significant against leukemia subpanel.

2-Aryl-6-methyl-3-phenylamino-6,7-dihydropyrano[4,3-c]pyrazol-4(2H)-ones with analgesic activity.

A series of 2-aryl-6-methyl-3-phenylamino-6,7-dihydropyrano[4,3-c]pyrazol-4(2H )-ones were prepared and tested for antiinflammatory, analgesic, antipyretic, antiarrhythmic, antihypertensive and platelet antiaggregating activities. All of them showed an appreciable level of analgesic activity in mice.

5-[[omega-(Dialkylamino)alkoxy]methylene]-1,3,3-trimethyl-2- oxabicyclo [2.2.2.]octan-6-ones with hypotensive, local anesthetic, antiarrhythmic and other activities.

The synthesis of 5-[[omega-(dialkylamino)alkoxy]methylene]-1,3,3-trimethyl-2- oxabicyclo[2.2.2]octan-6-ones by reaction of (+)-5-(hydroxymethylene)-1,3,3-trimethyl-2-oxabicyclo[2.2.2]octan- 6-one with a series of omega-(chloroalkyl)dialkylamines in the presence of potassium carbonate is described. Some compounds showed strong hypotensive, local anesthetic and antiarrhythmic activity in rats and mice, as well as moderate analgesic, antipyretic and in vitro platelet antiaggregating activity.