Abstract 872: Novel potent and orally active STAT3 inhibitors for cancer therapies.

Abstract

Abstract Signal transducers and activators of transcription (STATs) are proteins which have dual roles as cytoplasmic signaling proteins and transcription factors that activate sets of genes including those contribute to tumorigenesis. Among the STATs family members, STAT3 has been shown to play an important role in breast carcinogenesis and is often overexpressed in primary breast tumors. Increased STAT3 transcriptional activity is reported to correlate with ER-negative phenotype in breast cancer cell lines and in primary human invasive ductal breast carcinomas. Therefore, STAT3 is a promising target for breast cancer therapies. Current strategies of inhibiting STAT3 activity did not sufficiently block STAT3 activation in cancer cells due to their limited potency, poor solubility or bioavailability. Despite several STAT3 inhibitors have been advanced into early clinical trials, there is an urgent need to develop orally active, potent STAT3 inhibitors as cancer therapeutics. We have designed, synthesized and screened a series of novel STAT3 inhibitors utilizing fragment-based drug design strategy. A number of small molecules with novel scaffolds have been discovered with low-micromolar to nanomolar potency in inhibiting the proliferation of various human breast cancer and pancreatic cancer cells. The identified compounds HJC0152, HJC0123, HJC0125, and HJC0416 significantly suppress STAT3 promoter activity and STAT3 phosphorylation (pY705), reduce total STAT3 protein expression, induce cell growth arrest, and early apoptosis in ER-negative breast cancer cell line MDA-MB-231. These novel compounds have demonstrated a better efficacy in suppressing the growth of MDA-MB-231 breast xenograft tumors via intraperitoneal and oral administrative routes, with remarkably improved aqueous solubility and less toxicity than the lead compounds. In conclusion, we have developed a new class of orally active STAT3 inhibitors with superior drug-like properties, for further evaluation in cancer therapeutic and preventive settings. This work was supported by The University of Texas MD Anderson Cancer Center DFI Funding Program. Citation Format: Zhengduo Yang, Haijun Chen, Lili Chu, Yusong Zhang, Chunyong Ding, Huiling Liu, Jia Zhou, Qiang Shen. Novel potent and orally active STAT3 inhibitors for cancer therapies. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 872. doi:10.1158/1538-7445.AM2013-872