Targeting HE4 for treatment of endometrial cancer using a novel small molecule inhibitor.

Abstract

e17616 Background: HE4 expression is upregulated in endometrial cancer and has been shown to have prognostic significance in endometrial cancer patients. High-throughput screening and lead optimization led us to discover UR-238, a novel small molecule inhibitor of HE4. The purpose of this study was to investigate the in vitro and in vivo effects of UR-238 in treatment of endometrial cancer. Methods: UR-238 was identified by focused medicinal chemistry. Six endometrial cancer cell lines (ECC1, AN3CA, HEC1A, MFE296, MFE280, and KLE) were grown in cell culture and treated with 8 concentrations of UR-238 (125 nM, 250 nM, 375 nM, 500 nM, 625 nM, 750 nM, 875 nM, and 1000 nM) or DMSO (control). Cell proliferation was assessed using SRB assays at 24 and 48 hours. Effects of UR-238 on the cell cycle were assessed by flow cytometry and related cell-cycle proteins were targeted via Western blots. An ELISA was performed to evaluate UR-238 treatment effect on HE4 expression. An AN3CA xenograft mouse model was used to assess in vivo effects of UR-238. Mice were treated with vehicle control or UR-238 (5 mg/kg, IP, 3 days/week) for 20 days (N=5/group). Tumor volume and weight were evaluated over time using a repeated measures ANOVA. Results: UR-238 resulted in decreased cell proliferation in a dose-dependent manner in all 6 endometrial cancer cell lines. UR-238 increased expression of p21 and p27 and induced M/G2 cell cycle arrest. UR-238 also downregulated HE4 expression. In vivo treatment with UR-238 of AN3CA expressing xenograft mice caused a significant reduction (p=0.02) in mean tumor volume compared with vehicle control after 20 days (control mean 1068.13 mm3, SE 239.76; UR-238 mean 265.62 mm3, SE 68.82). Conclusions: UR-238 inhibits cell proliferation in endometrial cancer cell lines and exhibits antitumorigenic effects in xenograft mouse models. Future studies are warranted as UR-238 may be a promising therapeutic agent for treatment of endometrial cancer.