Bis-imide granulatimide analogues as potent Checkpoint 1 kinase inhibitors

Carbazole Derivatives as Kinase-Targeting Inhibitors for Cancer Treatment

Protein Kinases (PKs) are a heterogeneous family of enzymes that modulate several biological pathways, including cell division, cytoskeletal rearrangement, differentiation and apoptosis. In particular, due to their crucial role during human tumorigenesis and cancer progression, PKs are ideal targets for the design and development of effective and low toxic chemotherapeutics and represent the second group of drug targets after G-protein-coupled receptors. Nowadays, several compounds have been claimed to be PKs inhibitors, and some of them, such as imatinib, erlotinib and gefitinib, have already been approved for clinical use, whereas more than 30 others are in various phases of clinical trials. Among them, some natural or synthetic carbazole-based molecules represent promising PKs inhibitors due to their capability to interfere with PK activity by different mechanisms of action including the ability to act as DNA intercalating agents, interfere with the activity of enzymes involved in DNA duplication, such as topoisomerases and telomerases, and inhibit other proteins such as cyclindependent kinases or antagonize estrogen receptors. Thus, carbazoles can be considered a promising this class of compounds to be adopted in targeted therapy of different types of cancer.

Apoptotic events induced by maleimides on human acute leukemia cell lines

Cyclic imides are known for their antitumor activity, especially the naphthalimide derivatives, such as Mitonafide and Amonafide. Recently, we have demonstrated the cytotoxic effect of a series of naphthalimide derivatives against B16F10 melanoma cells. On the basis of this fact, we have developed a study starting from the synthesis of different cyclic imides and the evaluation of their cytotoxic properties on human acute leukemia cells (K562 and Jurkat). Initially, a screening test was conducted to select the compound with the best cytotoxic effect, using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. After this selection, structural modifications were performed in the most active compound to obtain five more derivatives. All compounds presented a good cytotoxic effect. The results of cell cycle analysis, fluorescence microscopy, and Annexin V-FITC assay confirmed that the cells observed in the sub-G0/G1 phase were undergoing apoptosis. From this set of results, cyclic imides 8, 10, and 12 were selected for the evaluation of the mechanisms involved in the apoptotic process. The results demonstrate the involvement of the intrinsic pathway of apoptosis, evidenced by the reduction in mitochondrial potential, an increase in the level of AIF protein expression, a decreased level of expression of anti-apoptotic Bcl-2 protein, and an increased level of expression of pro-apoptotic protein Bax in both K562 and Jurkat cells treated with cyclic imides (8, 10, and 12). Furthermore, cyclic imides 8 and 10 caused an increase in the level of Fas expression in Jurkat cells, indicating the additional involvement of the extrinsic apoptosis pathway. The compounds (8, 10, and 12) also caused a decreased level of expression of anti-apoptotic protein survivin. The biological effects observed with these cyclic imide derivatives in this study suggest promising applications against acute leukemia.

Synthesis, anti-inflammatory and analgesic evaluation of certain new 3a,4,9,9a-tetrahydro-4,9-benzenobenz[f]isoindole-1,3-diones

In an effort to establish new candidates with improved analgesic and anti-inflammatory activities, we reported here the synthesis and in-vivo analgesic and anti-inflammatory evaluation of various series of 2-substituted-3a,4,9,9a-tetrahydro-4,9-benzeno-benz[f]isoindole-1,3-diones: [4-Bromobutoxy] 6, 5-bromopentoxy 7, [4-(4-phenylpiperazin-1-yl)butoxy] 9, [5-(4-phenylpiperazin-1-yl)pentoxy] 10, 2-(2(4)-(4-phenylpiperazin-1-yl)-2-oxoethyl/4-oxobutyl 17, 19, [2(4)-(4-methylpiperazin-1-yl]-2-oxoethyl/4-oxobutyl 20, 22, [2(4)-morpholino-2-oxoethyl/4-oxobutyl] 23, 25, and 2(4)-(piperidin-1-yl)2-oxoethyl/4-oxobutyl) 26 and 28. The newly synthesized compounds were characterized by (IR, (1)H-, (13)C-NMR, and mass spectra). The representative compounds were evaluated as analgesic and anti-inflammatory activities. Compounds 9, 19, 22, 25, and 28 exhibited activities higher than the reference drug.

Marine pyrrolocarbazoles and analogues: synthesis and kinase inhibition

Granulatimide and isogranulatimide are alkaloids obtained from marine sources which have been shown to inhibit cell-cycle G2-checkpoint, targeting more particularly checkpoint 1 kinase (Chk1). At a structural level, they possess a characteristic pyrrolocarbazole framework also shared by the well-known rebeccamycin and staurosporine microbial metabolites which have been described to inhibit topoisomerase I and diverse kinases, respectively. This review reports precisely on the synthesis and kinase inhibitory activities of pyrrolocarbazole-based analogues of granulatimide.

Marine natural products

This review covers the literature published in 2007 for marine natural products, with 948 citations(627 for the period January to December 2007) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, cnidarians,bryozoans, molluscs, tunicates, echinoderms and true mangrove plants. The emphasis is on new compounds (961 for 2007), together with the relevant biological activities, source organisms and country of origin. Biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.1 Introduction, 2 Reviews, 3 Marine microorganisms and phytoplankton, 4 Green algae, 5 Brown algae, 6 Red algae, 7 Sponges, 8 Cnidarians, 9 Bryozoans, 10 Molluscs, 11 Tunicates (ascidians),12 Echinoderms, 13 Miscellaneous, 14 Conclusion, 15 References.

Palladium-catalyzed one-step synthesis of isoindole-1,3-diones by carbonylative cyclization of o-halobenzoates and primary amines

The palladium-catalyzed aminocarbonylation of o-halobenzoates produces 2-substituted isoindole-1,3-diones in good yields. This methodology provides a good one-step approach to this important class of heterocycles and tolerates a variety of functional groups, including methoxy, alcohol, ketone, and nitro groups.

Microwave-assisted synthesis of N-substituted cyclic imides and their evaluation for anticancer and anti-inflammatory activities

A number of N-substituted cyclic imides 3a-e, 5a-e, 7a-d, and 9a-e have been synthesized in very high yields, by condensation of various diacids 2, 4, 6, and 8 with different amines under microwave irradiation. These compounds were screened for anticancer and anti-inflammatory activities, and compounds 3c, 3e, 5c, 9c, and 9d exhibited anticancer activity against colon (COLO 205) cancer better than 5-fluorouracil and mitomycin-C, and compound 9b exhibited anti-inflammatory activity better than standard drug phenyl butazone.

Synthesis, checkpoint kinase 1 inhibitory properties and in vitro antiproliferative activities of new pyrrolocarbazoles

In the course of structure-activity relationship studies on granulatimide analogues, new pyrrolo[3,4-c]carbazoles have been synthesized in which the imidazole heterocycle was replaced by a five-membered ring lactam system or a dimethylcyclopentanedione. Moreover, the synthesis of an original structure in which a sugar moiety is attached to the indole nitrogen and to a six-membered D ring via an oxygen is reported. The inhibitory activities of the newly synthesized compounds toward checkpoint kinase 1 and their in vitro antiproliferative activities toward three tumor cell lines: murine leukemia L1210, and human colon carcinoma HT29 and HCT116 are described.

Synthesis, in vitro antiproliferative activities, and Chk1 inhibitory properties of pyrrolo[3,4-a]carbazole-1,3-diones, pyrrolo[3,4-c]carbazole-1,3-diones, and 2-aminopyridazino[3,4-a]pyrrolo[3,4-c]carbazole-1,3,4,7-tetraone

The synthesis of substituted pyrrolo[3,4-a]carbazole-1,3-diones, pyrrolo[3,4-c]carbazole-1,3-diones, and 2-aminopyridazino[3,4-a]pyrrolo[3,4-c]carbazole-1,3,4,7-tetraone is reported. Their inhibitory properties toward Checkpoint 1 kinase (Chk1) have been evaluated and their in vitro antiproliferative activities toward three tumor cell lines: murine leukemia L1210, human colon carcinoma HT29 and HCT116 have been determined. From the biological results, it appears that, in contrast with the upper E heterocycle, the lower D heterocycle is not absolutely required for Chk1 inhibition. The ATP binding pocket of Chk1 seems to be adaptable to substitution of the nitrogen of the imide E heterocycle with a hydroxymethyl group, allowing the fundamental hydrogen bond with the Glu(85) residue of the enzyme.

Synthesis and biological activities of new checkpoint kinase 1 inhibitors structurally related to granulatimide

In the course of structure-activity relationship studies on granulatimide analogues, new pyrrolo[3,4-c]carbazoles in which the imidazole heterocycle has been replaced by a five- or a six-membered ring bearing one or two carbonyl functions have been synthesized. Their checkpoint kinase 1 (Chk1) inhibitory properties and their in vitro antiproliferative activities toward three tumor cell lines-murine leukemia L1210 and human colon carcinoma HT29 and HCT116 have been determined. The results of molecular modeling in the ATP binding pocket of Chk1 are described. Among the newly synthesized compounds, compounds 13 and 16, in which the imidazole was replaced by a quinone and a hydroquinone and which bear a hydroxy group on the indole moiety, are the most potent Chk1 inhibitors in this series with IC50 values of 27 and 23 nM, respectively.

Optimization of a pyrazoloquinolinone class of Chk1 kinase inhibitors

The development of 2,5-dihydro-4H-pyrazolo[4,3-c]quinolin-4-ones as inhibitors of Chk1 kinase is described. Introduction of a fused ring at the C7/C8 positions of the pyrazoloquinolinone provided an increase in potency while guidance from overlapping inhibitor bound Chk1 X-ray crystal structures contributed to the discovery of a potent and solubilizing propyl amine moiety in compound 52 (Chk1 IC(50)=3.1 nM).