Synthesis of 3-substituted-2-oxoindole analogues and their evaluation as kinase inhibitors, anticancer and antiangiogenic agents

Cyclin-dependent kinases 5 template: useful for virtual screening

The present study reports the development of a template for the active binding site of Cdk5 for structure-based drug design. The developed template of Cdk5 was validated by redocking with ligands I (PBD code 1UNG), II (PBD code 1UNL) and III (PBD code 1UNH). The results demonstrate a good match of the docked and the crystallographic binding orientations with RMSD less than 2.0Å. The validation results show that the constructed Cdk5 template is a good model system for predicting ligand binding orientations and binding affinities. Furthermore, the developed template was applied to predict binding mode and binding affinity of thirty-six known Cdk5 inhibitors. The results showed that the binding energy of almost Cdk5 inhibitors related to their biological evaluation.

Synthesis and QSAR study of novel cytotoxic spiro[3H-indole-3,2'(1'H)-pyrrolo[3,4-c]pyrrole]-2,3',5'(1H,2'aH,4'H)-triones

1,3-Dipolar cycloaddition reaction of 1-aryl-1H-pyrrole-2,5-diones 1a-e with non-stabilized azomethine ylides, generated in situ via decarboxylative condensation of isatins 2a-c and sarcosine (3) in refluxing ethanol, afforded 4'-aryl-5'a,6'-dihydro-1'-methyl-spiro[3H-indole-3,2'(1'H)-pyrrolo[3,4-c]pyrrole]-2,3',5'(1H,2'aH,4'H)-triones 4a-o in good yields. Compound 4l exhibited high anti-tumor activity against HEPG2 (liver cancer) cell line (IC(50) = 12.16 μM) compared to that of Doxorubicin (IC(50) = 7.36 μM), and the other synthesized compounds revealed moderate anti-tumor properties against HCT116 (colon), MCF7 (breast) and HEPG2 (liver) human tumor cell lines. 3D-Pharmacophore modeling and quantitative structure-activity relationship (QSAR) analysis were combined to explore the structural requirements controlling the observed anti-tumor properties. It was found that the major structural factors affecting potency of these compounds were related to their basic skeleton.

Antiangiogenic properties of substituted (Z)-(±)-2-(N-benzylindol-3-ylmethylene)quinuclidin-3-ol/one analogs and their derivatives

In the past half century research efforts have defined a critical role for angiogenesis in tumor growth and metastasis. We previously reported that inhibition of a novel target, ENOX1, by a (Z)-2-benzylindol-3-ylmethylene) quinuclidin-3-ol, suppressed tumor angiogenesis. The present study was undertaken in order to establish structure-activity relationships for quinuclidine analogs. The angiogenesis inhibiting activity of a series of substituted (Z)-(±)-2-(N-benzylindol-3-ylmethylene)quinuclidin-3-ols (1a-1k), (Z)-2-benzylindol-3-ylmethylene)quinuclidin-3-ones (2a-2h), (Z)-(±)-2-(1H/N-methyl-indol-3-ylmethylene)quinuclidin-3-ols (3a-3b), and substituted (Z)-(±)-2-(N-benzenesulfonylindol-3-yl-methylene)quinuclidin-3-ols and their derivatives (4a-4d) that incorporate a variety of substituents in both the indole and N-benzyl moieties was evaluated using Human Umbilical Vein Endothelial Cells (HUVECs) subjected to in vitro cell migration scratch assays, tubule formation in Matrigel, cell viability and proliferation assays. In total, 25 different analogs were evaluated. Based on in vitro cell migration scratch assays, eight analogs were identified as potent angiogenesis inhibitors at 10 μM, a concentration that was determined to be nontoxic by colony formation assay. In addition, this approach identified a potent antiangiogenic ENOX1 inhibitor, analog 4b.

Highly diastereo- and enantioselective Michael additions of 3-substituted oxindoles to maleimides catalyzed by chiral bifunctional thiourea-tertiary amine

A highly diastereo- and enantioselective Michael addition reaction with respect to prochiral 3-substituted oxindoles and maleimides by a chiral bifunctional thiourea-tertiary amine catalyst was investigated for the first time. The corresponding adducts, containing a quaternary center at the C3-position of the oxindole as well as a vicinal tertiary center, were generally obtained in good to high yields (up to 92%) with high to excellent diastereo- (up to 99:1 dr) and enantioselectivities (up to 99% ee).

Highly enantioselective synthesis of 3-amino-2-oxindole derivatives: catalytic asymmetric alpha-amination of 3-substituted 2-oxindoles with a chiral scandium complex

A highly enantioselective alpha-amination of 3-substituted oxindoles with azodicarboxylates catalyzed by a chiral Sc(OTf)(3)/N,N'-dioxide complex (Tf: triflate) has been developed and affords the corresponding 3-amino-2-oxindole derivatives in high yields (up to 98%) with excellent enantioselectivities (up to 99% ee). The procedure is capable of tolerating a relatively wide range of substrates, and excellent results (92-96% ee) can also be obtained, even in the presence of 0.5 mol % of catalyst loading under mild conditions. These results showed the potential value of the catalytic approach. Moreover, with high synthetic versatility, the product could be easily transformed into optically active 3-amino-3-methyloxindole bearing a chiral quaternary stereogenic center.

Synthesis and evaluation of indole, pyrazole, chromone and pyrimidine based conjugates for tumor growth inhibitory activities--development of highly efficacious cytotoxic agents

Based upon the lead compounds 10 and 11, a number of conjugates were synthesized by the combination of chromone-pyrimidine, chromone-indolinone, chromone-pyrazole, indole-pyrimidine, indole-indolinone and indole-pyrazole moieties. Evaluation of these compounds for tumor growth inhibitory activities over 60 human tumor cell lines provided highly efficacious compounds 15, 41, 43, 66, 69, and 72 with an average GI(50) over all the 60 human tumor cell lines as 3.2 μM, 3.1 μM, 1.7 μM, 2.6 μM, 50.1 μM and 2.0 μM, respectively.

Adaptation of rat gastric tissue against indomethacin toxicity

Indomethacin is used in the treatment of inflammatory diseases. But the drug toxicity limits its usage. This study investigated whether adaptation occurred after various dosages of repeated (chronic) indomethacin in rats to the gastro-toxic effects of indomethacin. It also examined whether the adaptation was related to oxidant-antioxidant mechanisms and oxidative DNA damage in gastric tissue. To illuminate the adaptation mechanism in the gastric tissue of rats given various dosages of chronic indomethacin, the levels of oxidants and antioxidants (GSH, MDA, NO, SOD and MPO), activities of COX-1 and COX-2 enzymes and oxidative DNA damage (8-OHd Gua/10(5) Gua) were measured. Results were compared to 25-mg/kg single-dose indomethacin group, and the role of oxidant and antioxidant parameters and oxidative DNA damage in the adaptation mechanism was evaluated. The average ulcer areas of gastric tissue of the 0.5-, 1-, 2-, 3-, 4-, and 5-mg/kg dosages of chronic indomethacin given to rats were 19.5+/-3.7, 12.5+/-3.3, 10+/-5.2, 4.5+/-3.6, 8.6+/-2.4, and 9.5+/-2.1mm(2), respectively. This rate was measured as 21.3+/-2.6mm(2) in the single-dose indomethacin group. Consequently, after various dosages of repeated (chronic) indomethacin administration in rats, it was observed that a clear adaptation developed against gastric damage and that gastric damage was reduced. The best adaptation was observed in the gastric tissue of the 3-mg/kg chronic indomethacin group. In parallel with the damage reduction, the oxidant parameters (MDA and MPO) and oxidative DNA damage (8-OHd Gua/10(5) Gua) were reduced, and the antioxidant parameters (GSH, NO and SOD) were increased. There is no relation between COX enzymes and adaptation mechanism. This circumstance shows that not COX-1 and COX-2 enzymes, oxidant and antioxidant parameters may play a role in the adaptation mechanism.

Synthesis of symmetrical and unsymmetrical 3,3-di(indolyl)indolin-2-ones under controlled catalysis of ionic liquids

Three ionic liquids, [BMIM][BF₄] doped with 60 mol % of LiCl ([BMIM][BF₄]–LiCl), N,N,N,N-tetramethylguanidinium trifluoroacetate (TMGT), and N,N,N,N-tetramethylguanidinium triflate (TMGT_f) were found useful as catalyst solvents for controlled 3-indolylation of isatins. Our investigation revealed that the reaction between isatin and indoles in [BMIM][BF₄]–LiCl or TMGT_f media stops at the step of addition of the two components providing 3-indolyl-3-hydroxyindolin-2-ones while the ionic liquid TMGT runs the reaction further through accompanying Friedel–Crafts substitution to afford symmetrical 3,3-di(indol-3-yl)indolin-2-ones. To take advantage of the difference between the effects of these ionic liquids on the reaction progress, we planned a two-step protocol for the efficient synthesis of unsymmetrical 3,3-di(indol-3-yl)indolin-2-ones.

QSAR study of isatin analogues as in vitro anti-cancer agents

Quantitative structure activity relationships (QSAR) of anti-cancer isatin derivatives were discovered by multiple linear regressions (MLR) and genetic algorithm partial least squares (GA-PLS) methods. Topological, chemical, geometrical and functional groups descriptors were found to be effective parameters on the cytotoxic activity. The positive effects of the number of halogen atoms and the number of total secondary carbons, and the negative effects of the number of secondary amides, and the number of ketones on the anti-cancer activity were in agreement with previous SAR studies. Hansch analysis showed the importance of lipophilic R(3) and R(5) substituents. Between MLR and GA-PLS, MLR represented superior results with a high statistical quality (R(2)=0.92 and Q(2)=0.90) for predicting the activity of the compounds.

Role of alpha-2 adrenergic receptors in anti-ulcer effect mechanism of estrogen and luteinising hormone on rats

OBJECTIVE

To evaluate anti-ulcer effect of estrogen and luteinising hormone (LH) on indomethacin-induced ulcer model in female rats.

STUDY DESIGN

Ovariectomy in healthy adult famale rats. Acute administration of estradiol to ovariectomised rats. Acute administration of LH to intact rats. Combined administration of tamoxifen with estradiol or LH to intact rats. Combined administration of yohimbin with estradiol or LH to intact rats. Combined administration of piperoxan with estradiol or LH to intact rats. Indomethacin administration to all rats.

RESULTS

Results have shown that LH exerted anti-ulcer activity at all doses we used but estradiol at 5 and 10 mg/kg. In rats administered yohimbine and piperoxan estradiol and LH could not prevent indomethacin-induced ulcers. In rats administered tamoxifen, estradiol and LH could prevent indomethacin-induced ulcers.

CONCLUSIONS

LH is a very potent endogen anti-ulcer factor, and the anti-ulcerative activities of estrogen and LH are mediated via alpha-2 adrenergic receptors, but not es receptors. The resistance of gastric mucosa to aggressive factors may decrease as a result of LH inhibition when estrogen is secreted chronically in the human body.

In vitro cytotoxicity evaluation of some substituted isatin derivatives

A range of substituted 1H-indole-2,3-diones (isatins) were synthesized using standard procedures and their cytotoxicity evaluated against the human monocyte-like histiocytic lymphoma (U937) cell line in vitro. SAR studies identified C(5), C(6), and C(7) substitution greatly enhanced activity with some di- and tri-halogenated isatins giving IC(50) values <10 microM. Of the 23 compounds tested, four were selected for further screening against a panel of five human cancer cell lines. These compounds, in general, showed greater selectivity toward leukemia and lymphoma cells over breast, prostate, and colorectal carcinoma cell lines. The most active compound, 5,6,7-tribromoisatin (2p), was found to be antiproliferative at low micromolar concentrations and also activated the effector caspases 3 and 7 in a dose-dependent manner. These results indicate that di- and tri-substituted isatins may be useful leads for anticancer drug development in the future.