Investigation of furo[2,3-h]- and pyridazino[3,4-f]cinnolin-3-ol scaffolds as substrates for the development of novel HIV-1 integrase inhibitors

With the aim to develop novel HIV-1 integrase inhibitors, we obtained a set of condensed ring systems based on the furo[2,3-h]cinnolin-3(2H)-one and pyridazino[3,4-f]cinnolin-3-ol scaffolds bearing a potential chelating pharmacophore, which can be involved in the inhibition mechanism of the enzyme. Herein, we report the design, synthesis, structural investigation and preliminary biological results of these heteroaromatic systems

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 μM range MDM2 binding (KD =1.32 and 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

6-Amino-3-methyl-4-(3-nitro­phen­yl)-1-phenyl-1H,4H-pyrano[2,3-c]pyrazole-5-carbonitrile

The title compound, C20H15N5O3, was synthesized by the one-pot reaction of a four-component reaction protocol in aqueous medium. The pyrano[2,3-c]pyrazole system is essentially planar, with a maximum deviation of 0.026 (2) Å. The 3-nitro­phenyl and phenyl rings make dihedral angles of 81.11 (5) and 13.36 (1)°, respectively, with the mean plane of the pyrano[2,3-c]pyrazole ring. The crystal structure is stabilized by N—H⋯N hydrogen bonds, which form infinite chain propagating along the c axis and by N—H⋯O hydrogen bonds, which form infinite chains propagating along the a axis. There are also N—O⋯N—C dipole–dipole inter­actions along the a axis with an O⋯N distance of 3.061 (3) Å, which is shorter than that of the N—H⋯O hydrogen bond [3.196 (3) Å]

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