Cell experiment:

Breast cancer MDA-MB-231 cells are incubated in 6-well plates (2.5×105/well). Cells are then treated with DMSO, or HJC0152 hydrochloride (compound 11) at different concentrations for 48 h, and then both adherent and floating cells are collected, washed once with PBS. Resuspended cells are incubated with 100 μL PBS containing 1% BSA and 100 μL Annexin V and dead cell detection reagent at room temperature for 20 min. Apoptosis is measured immediately using the Muse Cell Analyzer with the MuseTM Apoptosis Kit[1].

Animal experiment:

in vivo administration.-->Fifty-four female nude mice are are used for orthotopic tumor studies at 4 to 6 weeks of age. The mice are maintained in a barrier unit with 12 h light-dark switch. Freshly harvested MDA-MB-231 cells (2.5×106 cells per mouse, resuspended in 100 μL PBS) are injected into the 3rd mammary fat pad of the mice, and then randomly assigned into 8 groups (5 to10 mice per group). For the intraperitoneal treatment experiment, the mice are treated daily with 2.5 mg/kg HJC0152 hydrochloride (compound 11) (Group A) or vehicle (Group D) when the tumor volume reaches 200 mm3. A Body weights and tumors volume are measured daily and tumor volume is calculated according to the formula V=0.5×L×W2, where L=length (mm) and W=width (mm)[1].

HJC0152 hydrochloride is a signal transducers and activators of transcription 3 (STAT3) inhibitor.

HJC0152 hydrochloride (compound 11) significantly inhibits cell proliferation and induces apoptosis accompanying cellular morphological changes at concentrations of 1, 5, and 10 μM. Results show that treatment with 10 μM HJC0152 hydrochloride decreases the STAT3 promoter activity in MDA-MB-231 cells by approximately 32%, and increasing the dose of HJC0152 hydrochloride to 20 μM further decreases STAT3 promoter activity by 62% as compare with control. Total STAT3 is reduced after treatment with HJC0152 hydrochloride. HJC0152 hydrochloride induces cleaved caspase-3 and down regulates cyclin D1 in MDA-MB-231 cells[1].

Mice treated with 7.5 mg/kg of HJC0152 hydrochloride (compound 11) via ip show a better effect in inhibiting tumor growth. The growth of xenograft tumors in mice is significantly reduced by HJC0152 hydrochloride at a dose of 25 mg/kg. It is also noteworthy that HJC0152 hydrochloride does not show significant signs of toxicity at a dose of 75 mg/kg[1].

[1]. Chen H, et al. Discovery of O-Alkylamino Tethered Niclosamide Derivatives as Potent and Orally Bioavailable Anticancer Agents. ACS Med Chem Lett. 2013 Feb 14;4(2):180-185.