miR-489 promotes apoptosis and inhibits invasiveness of glioma cells by targeting PAK5/RAF1 signaling pathways
ONCOLOGY REPORTS
Authors: Wang, Wei; Zhang, Luyang; Gao, Wei; Zhang, Dongyong; Zhao, Zilong; Bao, Yijun
Abstract
Glioma patients receiving therapy are at a high risk of relapse and rapid progression and, thus, more effective treatments are required. The aim of the present study was to determine the suppressive role of miR-489 as an alternative therapeutic target for preventing glioma progression. The results of the present study demonstrated that patients with relatively lower levels of expression of miR-489 had more favorable clinical outcomes. Furthermore, miR-489 expression was inversely correlated with p21-activated kinase 5 (PAK5) mRNA expression levels in glioma specimens. A dual luciferase reporter assay revealed that miR-489 suppressed PAK5 expression by directly targeting the PAK5 3'-untranslated region. The effects of miR-489 on cell viability were measured using MTT and Cell Counting Kit-8 assays. The results demonstrated that ectopic expression of miR-489 mimic decreased cell viability by interfering with cyclin D1 and c-Myc signaling. Additionally, the effect of miR-489 on apoptosis was determined using Hoechst 33258 staining and flow cytometry. The results demonstrated that miR-489 decreased the activity of RAF1, reduced Bcl-2 and promoted Bax expression, resulting in increased cell apoptosis. Furthermore, the effect of miR-489 mimic on cellular motility was assessed using migration and invasion assays. miR-489 was shown to abolish the PAK5/RAF1/MMP2 pathway, resulting in decreased cell invasion ability. These results indicated that miR-489 may be involved in PAK5-mediated regulation of glioma progression, demonstrating the potential therapeutic benefits of targeting miR-489 in glioma.
In vivo loss-of-function screens identify KPNB1 as a new druggable oncogene in epithelial ovarian cancer
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Authors: Kodama, Michiko; Kodama, Takahiro; Newberg, Justin Y.; Katayama, Hiroyuki; Kobayashi, Makoto; Hanash, Samir M.; Yoshihara, Kosuke; Wei, Zhubo; Tien, Jean C.; Rangel, Roberto; Hashimoto, Kae; Mabuchi, Seiji; Sawada, Kenjiro; Kimura, Tadashi; Copeland, Neal G.; Jenkins, Nancy A.
Abstract
Epithelial ovarian cancer (EOC) is a deadly cancer, and its prognosis has not been changed significantly during several decades. To seek new therapeutic targets for EOC, we performed an in vivo dropout screen in human tumor xenografts using a pooled shRNA library targeting thousands of druggable genes. Then, in follow-up studies, we performed a second screen using a genome-wide CRISPR/Cas9 library. These screens identified 10 high-confidence drug targets that included well-known oncogenes such as ERBB2 and RAF1, and novel oncogenes, notably KPNB1, which we investigated further. Genetic and pharmacological inhibition showed that KPNB1 exerts its antitumor effects through multiphase cell cycle arrest and apoptosis induction. Mechanistically, proteomic studies revealed that KPNB1 acts as a master regulator of cell cycle-related proteins, including p21, p27, and APC/C. Clinically, EOC patients with higher expression levels of KPNB1 showed earlier recurrence and worse prognosis than those with lower expression levels of KPNB1. Interestingly, ivermectin, a Food and Drug Administration-approved antiparasitic drug, showed KPNB1-dependent antitumor effects on EOC, serving as an alternative therapeutic toward EOC patients through drug repositioning. Last, we found that the combination of ivermectin and paclitaxel produces a stronger antitumor effect on EOC both in vitro and in vivo than either drug alone. Our studies have thus identified a combinatorial therapy for EOC, in addition to a plethora of potential drug targets.