Animal experiment:

Briefly, 5×106 A549 cells are injected subcutaneously in the flanks of 5-6-week-old male NOD/SCID mice. When the tumor volume reach about 50.0 mm3, the mice are randomized using online program into two different groups (6/group) with one group treated by formulation vehicle control and the other by A18 at 200 mg/kg with oral dosing 2-3 times a week for 4 weeks. One mouse in each group dies during the study and is eliminated. Tumor volume and body weight of the remaining five mice in each group are measured twice a week without blinding. On the thirty-fifth day after implant, mice are euthanized and the tumor tissues are harvested and weighed. Necropsy is also performed to determine changes in the heart, lungs, kidneys, liver and spleen.

inS3-54A18 is a potent STAT3 inhibitor, with anti-cancer properties.

inS3-54A18 (5 μM) reduces wound healing to 64% and 76% for A549 and MDA-MB-231 cells, respectively. inS3-54A18 at 10 μM further reduces the healing to 47% and 39%, respectively. inS3-54A18 inhibits the expression of STAT3 downstream target genes and the binding of STAT3 to its endogenous target sequences. inS3-54A18 does not affect the constitutive or IL-6-induced STAT3 activation (Tyr705 phosphorylation) but represses STAT3 target gene (survivin) expression[1].

inS3-54A18 (200 mg/kg, p.o.) inhibits tumor growth, metastasis and expression of STAT3 target genes in a mouse xenograft model of A549 cells[1].

[1]. Huang W, et al. Small-molecule inhibitors targeting the DNA-binding domain of STAT3 suppress tumor growth, metastasis and STAT3 target gene expression in vivo. Oncogene. 2016 Feb 11;35(6):783-92