HJC0152 hydrochloride (HJC0152) is a signal transducer and activator of transcription 3 (STAT3) inhibitor.

HJC0152 inhibits STAT3 promoter activity in MDA-MB-231 cells in a dose-dependent manner. It has a comparable potency in downregulating STAT3 protein production and phosphorylation at the Tyr-705 site. HJC0152 induces cleaved caspase-3 and downregulated cyclin D1 in MDA-MB-231 cells, inhibits cell cycle progression and promotes apoptosis. HJC0152 treatment efficiently suppresses HNSCC cell proliferation, arrests the cell cycle at the G0/G1 phase, induces apoptosis, and reduced cell invasion in both SCC25 and CAL27 cell lines. Moreover, HJC0152 inhibits nuclear translocation of phosphorylated STAT3 at Tyr705 and decreases VHL/β-catenin signaling activity via regulation of microRNA-21.

HJC0152 significantly suppresses MDA-MB-231 xenograft tumor growth in vivo (ip and po), indicating its great potential as efficacious and orally bioavailable therapeutics for human cancer. It has an improved oral bioavailability and an enhanced suppression of tumor growth in mice. HJC0152 does not show significant signs of toxicity at a dose of 75 mg/kg. In SCC25-derived orthotopic mouse models, HJC0152 treatment significantly abrogates STAT3/β-catenin expression in vivo, which leading to a global decrease of tumor growth and invasion.