title: Corosolic acid enhances the antitumor effects of chemotherapy on epithelial ovarian cancer by inhibiting signal transducer and activator of transcription 3 signaling.
abstract: Resistance to chemotherapy poses a serious problem for the treatment of advanced epithelial ovarian cancer patients. The mechanisms of chemoresistance are complex and studies have implicated signal transducer and activator of transcription 3 (STAT3) signaling in the chemoresistance of cancer cells. The present study investigated whether corosolic acid (CA), which has been previously reported to be a STAT3 inhibitor, was able to increase the sensitivity to chemotherapeutic drugs in epithelial ovarian cancer cells. CA also markedly enhanced the anticancer effect of paclitaxel, cisplatin and doxorubicin. In addition, CA abrogated the cell-cell interactions between macrophages and epithelial ovarian cancer cells and inhibited the macrophage-induced activation of epithelial ovarian cancer cells. These data indicated that CA was able to reverse the chemoresistance of epithelial ovarian cancer cells and suppress the cell-cell interaction with tumorigenic macrophages. Thus, CA may be useful as an adjuvant treatment to patients with advanced ovarian and other types of cancer due to the multiple anticancer effects.
authors.affiliation: Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Fujiwara
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Takaishi
authors.forename: Junko
authors.initials: J
authors.lastname: Nakao
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Ikeda
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Katabuchi
authors.forename: Motohiro
authors.initials: M
authors.lastname: Takeya
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Komohara
keywords: corosolic acid; macrophage; ovarian cancer; signal transducer and activator of transcription 3