Benzimidazolyl-pyrazolo[3,4-b]pyridinones, Selective Inhibitors of MOLT-4 Leukemia Cell Growth and Sea Urchin Embryo Spiculogenesis: Target Quest

Abstract

1,3-Substituted pyrazolo­[3,4-b]­pyridinones 11–18 were synthesized by a three-component condensation of Meldrum’s acid with aryl aldehydes and 1,3-substituted 5-aminopyrazoles. Their biological activity was evaluated using the in vivo phenotypic sea urchin embryo assay and the in vitro cytotoxicity screen against human cancer cell lines. In the sea urchin embryo model, 1-benzimidazolyl-pyrazolo­[3,4-b]­pyridinones 11 caused inhibition of hatching and spiculogenesis at sub-micromolar concentrations. These compounds also selectively and potently inhibited growth of the MOLT-4 leukemia cell line. Subsequent structure–activity relationship studies determined the benzimidazolyl fragment as an essential pharmacophore for both effects. We applied numerous techniques for target identification. A preliminary QSAR target identification search did not result in tangible leads. Attempts to prepare a relevant photoaffinity probe that retained potency in both assays were not successful. Compounds 11 were further characterized for their activity in wild-type versus Notch-mutant leukemia cell lines, and in in vitro panels of kinases and matrix metalloproteinases. Using a series of diverse modulators of spiculogenesis as standards, we excluded multiple signaling networks including Notch, Wnt/β-catenin, receptor tyrosine kinases (VEGF/VEGFR, FGF/FGFR), PI3K, and Raf-MEK-ERK as possible targets of 11. On the other hand, matrix metalloproteinase-9/hatching enzyme was identified as one potential target.

Synthesis, Screening and Characterization of Novel Potent Arp2/3 Inhibitory Compounds Analogous to CK-666

“…The sea urchin embryo is a suitable model for compound screening ( Semenova et al, 2008 , 2018 ; Lichitsky et al, 2019 ). The phenotype associated with CK-666 mediated Arp2/3 inhibition ( Sepúlveda-ramírez et al, 2018 ) was confirmed here with two other Arp2/3 inhibitory compounds.…”

Copper(ii) coordination compounds based on bis-hydrazones of 2,6-diacetylpyridine: synthesis, structure, and cytotoxic activity

“…2-Hydrazinobenzimidazolе was synthesized according to the published method. 26 1-Hydrazinophthalazine hydrochloride (hydralazine) (98%) and 2,6-diacetylpyridine (99%) were acquired from Alfa Aesar. Copper salts (98%) were purchased from Alfa Aesar.…”

Asymmetric [3 + 3] Annulation to Construct Trifluoromethylated Pyrazolo[3,4-b]pyridin-6-ones via Chiral Phosphoric Acid and MgSO4 Synergistic Catalysis

“…For example, pyrazolo­[3,4- b ]­pyridin-6-ones were first synthesized by condensation of ethylidenemalonic acid diethyl ester and 1-ethyl-5-amino-methylpyrazole . Moreover, the synthesis of pyrazolo­[3,4- b ]­pyridin-6-one derivatives by a three-component reaction of an aldehyde, Meldrum acid, and aminopyrazole under various conditions , and with organic and inorganic catalysts (Scheme , i-(a) and i-(b)) has been reported previously, but no asymmetric version has been disclosed. In 2011, Chkanikov and co-workers synthesized 6,7-dihydro-1 H -pyrazolo-[3,4 b ]-pyridin-6-ones with 4-ArSCF 2 and 4-ArSCHF groups by direct annulation of 1-substituted 5-aminopyrazoles with ethyl 4,4-difluoro-4-phenylthioacetoacetate (Scheme , i-(c)) .…”