Molecular hybridization design and synthesis of novel spirooxindole-based MDM2 inhibitors endowed with BCL2 signaling attenuation; a step towards the next generation p53 activators.

Despite the achieved progress in developing efficient MDM2-p53 protein-protein interaction inhibitors (MDM2 inhibitors), the acquired resistance of tumor cells to such p53 activators posed an argument about the druggability of the pathway. Combination studies disclosed that concomitant inhibition of MDM2 and BCL2 functions can sensitize the tumor cells and synergistically induce apoptosis. Herein, we employed a rapid combinatorial approach to generate a novel series of hybrid spirooxindole-based MDM2 inhibitors (5a-s) endowed with BCL2 signaling attenuation. The adducts were designed to mimic the thematic features of the chemically stable potent spiro[3H-indole-3,2'-pyrrolidin]-2(1H)-ones MDM2 inhibitors while installing a pyrrole ring on the core via a carbonyl spacer inspired by the natural product marinopyrrole A that efficiently inhibits BCL2 family functions by various mechanisms. NCI 60 cell-line panel screening revealed their promising broad-spectrum antiproliferative activities. The NCI-selected derivatives were screened for cytotoxic activities against normal fibroblasts, MDA-MB 231, HepG-2, and Caco-2 cells via MTT assay, subjected to mechanistic apoptosis studies for assessment of p53, BCL2, p21, and caspase 3/7 status, then evaluated for potential MDM2 inhibition utilizing MST assay. The most balanced potent and safe derivatives; 5i and 5q were more active than 5-fluorouracil, exhibited low µmrange MDM2 binding (KD=1.32and 1.72 µm, respectively), induced apoptosis-dependent anticancer activities up to 50%, activated p53 by 47-63%, downregulated the BCL2 gene to 59.8%, and reduced its protein level (13.75%) in the treated cancer cells. Further downstream p53 signaling studies revealed > 2 folds p21 upregulation and > 3 folds caspase 3/7 activation. Docking simulations displayed that the active MDM2 inhibitors resided well into the p53 binding sites of MDM2, and shared key interactions with the co-crystalized inhibitor posed by the indolinone scaffold (5i, 5p, and 5q), the halogen substituents (5r), or the installed spiro ring (5s). Finally, in silico ADMET profiling predicted acceptable drug-like properties with full accordance to Lipinski's, Veber's, and Muegge's bioavailability parameters for 5i and a single violation for 5q.

Synthesis of new spirooxindole-pyrrolothiazole derivatives: Anti-cancer activity and molecular docking.

The 1,3-dipolar cycloadditions of an azomethine ylide generated from isatin and thiazolidinecarboxylic acid to a series of 2,6-bis[(E)-arylmethylidene]cyclohexanones afforded new di-spiro heterocycles incorporating pyrrolidine and oxindole rings in quantitative yields and chemo-, regio-, and stereoselectively. The newly synthesized compounds were characterized using spectroscopic techniques. Furthermore, the molecular structures of 4a, 4e, and 4n were confirmed by X-ray crystallography. These newly synthesized compounds were screened for their in vitro activity against breast cancer cell line MCF-7 and K562-leukemia. 4k was found to be the most potent compound of this series in targeting MCF-7 breast cancer cells and K562-leukemia, with IC50 values of 15.32±0.02 and 14.74±0.7µM, respectively. The molecular studies of the synthesized compounds were investigated.

New Diethyl Ammonium Salt of Thiobarbituric Acid Derivative: Synthesis, Molecular Structure Investigations and Docking Studies.

The synthesis of the new diethyl ammonium salt of diethylammonium(E)-5-(1,5-bis(4-fluorophenyl)-3-oxopent-4-en-1-yl)-1,3-diethyl-4,6-dioxo-2-thioxohexaydropyrimidin-5-ide 3 via a regioselective Michael addition of N,N-diethylthiobarbituric acid 1 to dienone 2 is described. In 3, the carboanion of the thiobarbituric moiety is stabilized by the strong intramolecular electron delocalization with the adjacent carbonyl groups and so the reaction proceeds without any cyclization. The molecular structure investigations of 3 were determined by single-crystal X-ray diffraction as well as DFT computations. The theoretically calculated (DFT/B3LYP) geometry agrees well with the crystallographic data. The effect of fluorine replacement by chlorine atoms on the molecular structure aspects were investigated using DFT methods. Calculated electronic spectra showed a bathochromic shift of the π-π* transition when fluorine is replaced by chlorine. Charge decomposition analyses were performed to study possible interaction between the different fragments in the studied systems. Molecular docking simulations examining the inhibitory nature of the compound show an anti-diabetic activity with Pa (probability of activity) value of 0.229.

Design, Synthesis, Chemical and Biochemical Insights Into Novel Hybrid Spirooxindole-Based p53-MDM2 Inhibitors With Potential Bcl2 Signaling Attenuation.

The tumor resistance to p53 activators posed a clinical challenge. Combination studies disclosed that concomitant administration of Bcl2 inhibitors can sensitize the tumor cells and induce apoptosis. In this study, we utilized a rapid synthetic route to synthesize two novel hybrid spirooxindole-based p53-MDM2 inhibitors endowed with Bcl2 signaling attenuation. The adducts mimic the thematic features of the chemically stable potent spiro [3H-indole-3,2'-pyrrolidin]-2(1H)-ones p53-MDM2 inhibitors, while installing a pyrrole ring via a carbonyl spacer inspired by the natural marine or synthetic products that efficiently inhibit Bcl2 family functions. A chemical insight into the two synthesized spirooxindoles including single crystal x-ray diffraction analysis unambiguously confirmed their structures. The synthesized spirooxindoles 2a and 2b were preliminarily tested for cytotoxic activities against normal cells, MDA-MB 231, HepG-2, and Caco-2 via MTT assay. 2b was superior to 5-fluorouracil. Mechanistically, 2b induced apoptosis-dependent anticancer effect (43%) higher than that of 5-fluorouracil (34.95%) in three studied cancer cell lines, activated p53 (47%), downregulated the Bcl2 gene (1.25-fold), and upregulated p21 (2-fold) in the treated cancer cells. Docking simulations declared the possible binding modes of the synthesized compounds within MDM2.

Regio- and stereoselective synthesis of new spirooxindoles via 1,3-dipolar cycloaddition reaction: Anticancer and molecular docking studies.

Owing to their structural novelty and inherent three-dimensionality, spiro scaffolds have been shown indisputable promise as chemopreventive agents. A new series of heterocycles containing spirooxindole and pyrrolidine rings were synthesized by the 1,3-dipolar cycloaddition of an azomethine ylide, which was generated in situ by the condensation of a secondary amino acid (l­proline) and dicarbonyl compounds (isatin), with dipolarophiles. This method is simple and provides diverse and biologically interesting products. The new series of compounds with a high degree of stereo- and regioselectivity were evaluated against breast cancer cell lines (MCF-7) and leukemia (K562). Among them, compound 4g was identified as the most potent with IC50 values of 15.49 ±â€¯0.04 µM, against breast cancer cell lines (MCF-7) compared to standard drug 5-Fu (IC50 = 78.28 ±â€¯0.2 µM) and compound 4i IC50 values of 13.38 ±â€¯0.14 µM against leukemia (K562) compared to standard drug 5-fluorouracil (5-FU) (IC50 = 38.58 ±â€¯0.02). The selective apoptotic effects of 4g were investigated against MCF-12 normal mammary cell and the cytotoxicity of 4g was not associated with any induction of necrosis compared to untreated cells. Molecular docking studies were investigated. From the docking data, these compounds could be act as small molecules that inhibit the MDM2-p53 interaction.

Synthesis and dynamics studies of barbituric acid derivatives as urease inhibitors.

BACKGROUND: Discovery of potent inhibitors of urease (jack bean) enzyme is the first step in the development of drugs against diseases caused by ureolytic enzyme. RESULTS: Thirty-two derivatives of barbituric acid as zwitterionic adducts of diethyl ammonium salts were synthesized. All synthesized compounds (4a-z and 5a-s) were screened for their in vitro inhibition potential against urease enzyme (jack bean urease). The compounds 4i (IC50 = 17.6 ± 0.23 µM) and 5l (IC50 = 17.2 ± 0.44 µM) were found to be the most active members of the series, and showed several fold more urease inhibition activity than the standard compound thiourea (IC50 = 21.2 ± 1.3 µM). Whereas, compounds 4a-b, 4d-e, 4g-h, 4j-4r, 4x, 4z, 5b, 5e, 5k, 5n-5q having IC50 values in the range of 22.7 ± 0.20 µM-43.8 ± 0.33 µM, were also found as potent urease inhibitors. Furthermore, Molecular Dynamics simulation and molecular docking studies were carried out to analyze the binding mode of barbituric acid derivatives using MOE. During MD simulation enol form is found to be more stable over its keto form due to their coordination with catalytic Nickel ion of Urease. Additionally, structural-activity relationship using automated docking method was applied where the compounds with high biological activity are deeply buried within the binding pocket of urease. As multiple hydrophilic crucial interactions with Ala169, KCX219, Asp362 and Ala366 stabilize the compound within the binding site, thus contributing greater activity. CONCLUSIONS: This research study is useful for the discovery of economically, efficient viable new drug against infectious diseases.Graphical abstract:STD. Thiourea (IC50 = 21.2 ± 1.3 µM).