Synthesis of new class of indole acetic acid sulfonate derivatives as ectonucleotidases inhibitors.

Ectonucleotidases inhibitors (ENPPs, e5'NT (CD73) and h-TNAP) are potential therapeutic candidates for the treatment of cancer. Adenosine, the cancer-developing, and growth moiety is the resultant product of these enzymes. The synthesis of small molecules that can increase the acidic and ionizable structure of adenosine 5-monophosphate (AMP) has been used in traditional attempts to inhibit ENPPs, ecto-5'-nucleotidase and h-TNAP. In this article, we present a short and interesting method for developing substituted indole acetic acid sulfonate derivatives (5a-5o), which are non-nucleotide based small molecules, and investigated their inhibitory potential against recombinant h-ENPP1, h-ENPP3, h-TNAP, h-e5'NT and r-e5'NT. Their overexpression in the tumor environment leads to high adenosine level that results in tumor development as well as immune evasion. Therefore, selective, and potent inhibitors of these enzymes would be expected to decrease adenosine levels and manage tumor development and progression. Our intended outcome led to the discovery of new potent inhibitors like' 5e (IC50 against h-ENPP1 = 0.32 ± 0.01 µM, 58 folds increased with respect to suramin), 5j (IC50 against h-ENPP3 = 0.62 ± 0.003 µM, 21 folds increase with respect to suramin), 5c (IC50 against h-e5'NT = 0.37 ± 0.03 µM, 115 folds increase with respect to sulfamic acid), 5i (IC50 against r-e5'NT = 0.81 ± 0.05 µM, 95 folds increase with respect to sulfamic acid), and 5g (IC50 against h-TNAP = 0.59 ± 0.08 µM, 36 folds increase with respect to Levamisole). Molecular docking studies revealed that inhibitors of these selected target enzymes induced favorable interactions with the key amino acids of the active site, including Lys255, Lys278, Asn277, Gly533, Lys528, Tyr451, Phe257, Tyr340, Gln465, Gln434, Lys437, Glu830, Cys818, Asn499, Arg40, Phe417, Phe500, Asn503, Asn599, Tyr281, Arg397, Asp526, Phe419 and Tyr502. Enzyme kinetic studies revealed that potent compounds such as 5j and 5e blocked these ectonucleotidases competitively while compounds 5e and 5c presented an un-competitive binding mode. 5g revealed a non-competitive mode of inhibition.

Synthesis, Characterization, and In Silico Studies of Novel Spirooxindole Derivatives as Ecto-5'-Nucleotidase Inhibitors.

Ecto-5'-nucleotidase (ecto-5'-NT, CD73) inhibitors are promising drug candidates for cancer therapy. Traditional efforts used to inhibit the ecto-5'-nucleotidase have involved antibody therapy or development of small molecule inhibitors that can mimic the acidic and ionizable structure of adenosine 5'-monophosphate (AMP). Herein, we report an efficient, environment friendly route for the synthesis of non-nucleotide based small molecules, i.e., substituted spirooxindole derivatives 9a-9l and investigated their inhibitory potential on human and rat recombinant ecto-5'-nucleotidase isozymes. These attempts have resulted in the identification of compound 9f (IC50 = 0.15 ± 0.02 µM) inhibitor on h-ecto-5'-NT which showed 280-fold higher inhibition and compound 9h (IC50 ± 0.19 ± 0.03 µM) on r-ecto-5'-NT with 406-fold enhanced inhibition than reference standard sulfamic acid. Moreover, in silico studies were carried out to assess binding interactions of potent compounds within enzyme active sites and demonstrated excellent correlation with the experimental findings.