Chaetoglobosin K (ChK) is an indolylcytochalasin isolated from the fungus Diplodia macrospora that has shown anti-tumorigenic effects in multiple human lung and ovarian carcinoma cell lines. We have previously reported that ChK decreases Akt activation and modulates key downstream Akt/mTOR pathway effectors in tumorigenic cells. The down-regulation of Akt activation by ChK is independent of class I PI3K enzyme inhibition or the upstream mediators PDK1, PTEN, and mTORC2. The purpose of these studies was to investigate the effect of ChK on the proliferation and migration of prostate carcinoma cells of various metastatic potential and PTEN status. The activation of Akt was monitored to assess the ability of ChK to inhibit Akt in prostate carcinoma cells. In these studies, MTT assays were used to measure the number of viable PC3, DU145, and LNCaP cells treated with ChK. Scratch wound and transwell migration assays were utilized to examine the effect of ChK on cell migration. To assess Akt activation, western blot analysis was performed to measure changes in Akt phosphorylation at the ser473 and thr308 sites after cells were treated with ChK or vehicle. ChK was found to inhibit the number of viable PC3, DU145, and LNCaP cells with IC50 values in the 3-5μM range. ChK inhibited migration of PC3 cells into the wound space at 1μM by approximately 60% after 72 hours as compared to vehicle treated controls. ChK inhibited transwell migration of PC3 cells by greater than 90% compared to controls after 5 hours. Additionally, ChK treatment lowered Akt phosphorylation at key activation sites. In summary, ChK inhibits the proliferation, migration, and Akt activation of prostate carcinoma cells in vitro. Further mechanistic studies of ChK will substantiate its therapeutic potential in the treatment of prostate and other cancers.

Citation Format: Amna Ali, Silvia Caggia, Diane F. Matesic, Shafiq A. Khan. Chaetoglobosin K, an Akt pathway inhibitor, prevents proliferation and migration of prostate carcinoma cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2669. doi:10.1158/1538-7445.AM2015-2669