Synthesis and Biological Evaluation of Novel 2-Amino-1,4-Naphthoquinone Amide-Oxime Derivatives as Potent IDO1/STAT3 Dual Inhibitors with Prospective Antitumor Effects.

Indoleamine-2,3-dioxygenase 1 (IDO1) and signal transducer and activator of transcription 3 (STAT3) have emerged as significant targets in the tumor microenvironment for cancer therapy. In this study, we synthesized three novel 2-amino-1,4-naphthoquinone amide-oxime derivatives and identified them as dual inhibitors of IDO1 and STAT3. The representative compound NK3 demonstrated effective binding to IDO1 and exhibited good inhibitory activity (hIDO1 IC50 = 0.06 µM), leading to its selection for further investigation. The direct interactions between compound NK3 and IDO1 and STAT3 proteins were confirmed through surface plasmon resonance analysis. A molecular docking study of compound NK3 revealed key interactions between NK3 and IDO1, with the naphthoquinone-oxime moiety coordinating with the heme iron. In the in vitro anticancer assay, compound NK3 displayed potent antitumor activity against selected cancer cell lines and effectively suppressed nuclear translocation of STAT3. Moreover, in vivo assays conducted on CT26 tumor-bearing Balb/c mice and an athymic HepG2 xenograft model revealed that compound NK3 exhibited potent antitumor activity with low toxicity relative to 1-methyl-L-tryptophan (1-MT) and doxorubicin (DOX). Overall, these findings provided evidence that the dual inhibitors of IDO1 and STAT3 may offer a promising avenue for the development of highly effective drug candidates for cancer therapy.

New inhibitors of matrix metalloproteinases 9 (MMP-9): Lignans from Selaginella moellendorffii.

Matrix metalloproteinase 9 (MMP-9) is one of the structurally related zinc-dependent endopeptidases families and provides a new target for cancer therapy owing to its pivotal role in metastatic tumors. In this paper, fourteen lignans, including three novel lignans, named selamoellenin B-D (1-3), and eleven known lignan derivatives (4-14) were isolated from the plant of Selaginella moellendorffii. Among them, compound 3 is optically active, which was enantiomerically seperated to afford a pair of enantiomers, (-)-3 and (+)-3. Their structures were elucidated by extensive spectroscopic analyses. Their cytotoxic activities were evaluated against four human cancer cell lines. Among them, five compounds (4, 5, 6, 11 and 13) exhibited great potent cytotoxicity and their structure-activity relationships were also discussed. All compounds except for 3 lignan analogues with low cytotoxicity were selected for further in vitro enzyme inhibition, surface plasmon resonance (SPR), and molecular docking assays based on the MMPs target. The results shown that, compound 11 have the best inhibitory effect and can be considered as a potential drug candidate targeting at MMP-9 for cancer therapy.