RESUMO
The diaryl urea is an important fragment/pharmacophore in constructing anticancer molecules due to its near-perfect binding with certain acceptors. The urea NH moiety is a favorable hydrogen bond donor, while the urea oxygen atom is regarded as an excellent acceptor. Many novel compounds have been synthesized and evaluated for their antitumor activity with the successful development of sorafenib. Moreover, this structure is used to link alkylating pharmacophores with high affinity DNA binders. In addition, the diaryl urea is present in several kinase inhibitors, such as RAF, KDR and Aurora kinases. Above all, this moiety is used in the type II inhibitors: it usually forms one or two hydrogen bonds with a conserved glutamic acid and one with the backbone amide of the aspartic acid in the DFG motif. In addition, some diaryl urea derivatives act as Hedgehog (Hh) ligands, binding and inhibiting proteins involved in the homonymous Hh signaling pathway. In this review we provide some of the methodologies adopted for the synthesis of diaryl ureas and a description of the most representative antitumor agents bearing the diaryl urea moiety, focusing on their mechanisms bound to the receptors and structure-activity relationships (SAR). An increased knowledge of these derivatives could prompt the search to find new and more potent compounds.
Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Neoplasias/tratamento farmacológico , Ureia/análogos & derivados , Ureia/farmacologia , Animais , Proteínas Hedgehog/antagonistas & inibidores , Proteínas Hedgehog/metabolismo , Humanos , Neoplasias/metabolismo , Neoplasias/patologia , Ureia/químicaRESUMO
The limitations of many mono-kinase inhibitors can be overcome by agents with multi-target action. An important advantage of targeting more than one kinase, is an increase in potency, due to the synergistic effect. Moreover, this approach can reduce the possibility of developing drug resistance. Several multitarget agents have been designed as single kinase inhibitors and found to be multi-target inhibitors because of the structural homology among the ATP-binding site of kinases. In other cases, these inhibitors have been obtained by optimization of potent individual inhibitors or by combination of selective ligands. Also some irreversible inhibitors act on different kinases and covalently modify the cysteine residues located near the ATP-binding pocket. In this review the most recent examples of multi-kinase inhibitors are reported, focusing on chemical structures, structure-activity relationship (SAR) and biological activity. These inhibitors, suitably substituted, could be used in designing other multitarget agents. Virtual molecular docking would suggest potential targets of molecules, moreover combining pharmacophore combination and screening methods could probably help in the discovery of more potent multikinase inhibitors.
Assuntos
Inibidores de Proteínas Quinases/farmacologia , Proteínas Quinases/metabolismo , Animais , Humanos , Indóis/química , Indóis/farmacologia , Inibidores de Proteínas Quinases/química , Proteínas Quinases/química , Piridinas/química , Piridinas/farmacologia , Pirimidinas/química , Pirimidinas/farmacologiaRESUMO
Benzimidazole is a common kinase inhibitor scaffold and benzimidazole-based compounds interact with enzymes by multiple binding modes. In some cases, the benzimidazole acts as part of the hinge-binding motif, in others it has a scaffolding role without evidence for direct hinge binding. Several of these compounds are ATP-competitive inhibitors and show high selectivity by exploiting unique structural properties that distinguish one kinase from the majority of other kinases. However, the high specificity for a single target is not always sufficient. Thus another approach, called multi-target therapy, has been developed over the last few years. The simultaneous inhibition of various kinases may be useful because the disease is attacked at several relevant targets. Moreover, if a kinase becomes drug-resistant, a multitargeted drug can act on the other kinases. Some benzimidazole derivatives are multi-target inhibitors. In this article benzimidazole inhibitors are reported with their mechanisms of action, structure-activity relationship (SAR) and biological properties.
Assuntos
Benzimidazóis/química , Inibidores de Proteínas Quinases/química , Benzimidazóis/farmacologia , Linhagem Celular , Humanos , Modelos Moleculares , Inibidores de Proteínas Quinases/farmacologia , Estrutura Terciária de Proteína , Relação Estrutura-AtividadeRESUMO
Aurora kinases represent one of the emerging targets in oncology drug discovery. These kinases play important role in centrosome maturation, chromosome separation and cytokinesis. They are overexpressed in a broad range of tumor cell lines and human primary tumors; thus, their inhibition may open up new opportunities to develop novel anti-cancer agents. A range of potent small molecule inhibitors of Aurora kinases have been identified and found to have antitumor activity. Some of these agents are undergoing evaluation in clinical trials. Most synthetic Aurora kinase inhibitors are ATP-competitive, which makes selectivity a potential problem. However, despite the high sequence similarity in the ATP-binding pocket, several compounds are very specific in their targets. The ability of the inhibitors to extend their binding to regions adjacent to the ATP pocket, including the hydrophobic back pocket, contributes to the selectivity, since structural differences can be found in these regions. A common structural feature of the inhibitors is a planar heterocyclic ring system able to occupy the adenino-binding region and to mimic the adenine-kinase interactions, by making backbone hydrogen bond interactions, but also by extensive hydrophobic contacts within this part of the pocket. In this review we would like to analyse the main inhibitors, focusing on chemical structures, SAR and biological properties. The specific targeting of these kinases could result in highly active drugs with minimal collateral host toxicity. Moreover, the combination of Aurora inhibitors with other chemotherapeutic agents may open new opportunities in cancer chemotherapy.
Assuntos
Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Animais , Aurora Quinases , Humanos , Mutação , Compostos Orgânicos/química , Compostos Orgânicos/farmacologia , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismoRESUMO
Inhibition of Cdc25 phosphatases is a strategy for the discovery and development of novel anticancer agents targeting the cell cycle. A number of potent small molecule Cdc25 inhibitors have been identified. They are derived from different chemical classes; the most potent and selective derivatives are quinones. The electrophilic properties of quinones suggest the possibility of inducing a sulphydryl arylation of a cysteine in the enzyme active site. It is also possible that inhibition is due to redox cycling activity and production of ROS. Thus, oxidation of the thiolate form of cysteine occurs, leading to inactivation of enzymatic activity. Many of these inhibitors are active on all three Cdc25 phosphatases, cause cell cycle arrest and inhibit the growth of several human tumor cell lines. The possibility of toxicities induced by ROS, prompted the search for non-quinoid antagonists. It is not yet clear how these compounds bind within the enzyme's active site. Generally, electrophilic moieties able to trap the catalytic cysteine play an important role. Another strategy for identifying Cdc25 inhibitors is the development of compounds able to interact with the conserved loop region instead of phosphate.. In this review a summary of the most interesting Cdc25 inhibitors is given together with their biological activity. SAR studies concerning the importance of some structural features will be described.
Assuntos
Antineoplásicos/química , Inibidores Enzimáticos/química , Fosfatases cdc25/antagonistas & inibidores , Antineoplásicos/farmacologia , Ciclo Celular/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Humanos , Maleimidas/química , Maleimidas/farmacologia , Estrutura Molecular , Naftoquinonas/química , Naftoquinonas/farmacologia , Quinonas/química , Quinonas/farmacologia , Relação Estrutura-AtividadeRESUMO
The development of prodrugs that are enzymatically activated into anticancer agents is a promising perspective in cancer therapy. Many nitrogen-containing quinoid heterocycles have been reported to show antitumor effect. The principal interest in these compounds lies on their potential to produce tumor-selective toxicity. Selectivity occurs by difference in oxygen tension between normal and tumor tissue and by levels of the required activating enzymes. In this review a summary of the most interesting heterocyclic quinones is given together with their biological property. SAR studies concerning the importance of some structural features will be described.
Assuntos
Antineoplásicos/química , Desenho de Fármacos , Compostos Heterocíclicos/química , Nitrogênio/análise , Quinonas/química , Animais , Antineoplásicos/farmacologia , Compostos Heterocíclicos/farmacologia , Humanos , Oxirredução , Quinonas/farmacologia , Relação Estrutura-AtividadeRESUMO
Ten benzimidazole-4,7-diones were synthesized and tested in vitro on two tumor cell lines. Several compounds showed a significant antiproliferative activity on K562 cells, although to a different extent, whereas compound 1i showed a highly significant activity on SW620 cells, comparable to that of doxorubicin. Both the substituents in the quinone ring and the position of the nitrogen atom in the pyridine moiety play a crucial role for the biological activity.
Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Benzimidazóis/síntese química , Benzimidazóis/farmacologia , Cetonas/síntese química , Cetonas/farmacologia , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Células K562 , Estrutura Molecular , Inibidores da Síntese de Ácido Nucleico/síntese química , Inibidores da Síntese de Ácido Nucleico/farmacologia , Relação Estrutura-AtividadeRESUMO
Some benzimidazolyl sulphones were synthesized and evaluated for their antiviral and antiproliferative properties. Compound 10 displayed significant and selective activity against human cytomegalovirus (CMV), compound 14 showed activity against varicella zoster virus (VZV). The compounds were further evaluated for inhibitory effect on the proliferation of murine leukemia cells and human T-lymphocyte cells. Marked cytotoxicity was noted with different derivatives. Some structure-activity relationships are discussed.