Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, Japan.
Department of Obstetrics and Gynecology, Faculty of Medicine, The University of Tokyo, Japan; Current address; Department of Obstetrics and Gynecology, Nihon University, Tokyo, Japan.
Gynecol Oncol. 2019 Nov;155(2):331-339. doi: 10.1016/j.ygyno.2019.08.028. Epub 2019 Sep 5.
PI3K pathway signaling has received attention as a molecular target in clear cell ovarian carcinoma (CCOC). MDM2 is one of the AKT effectors in the PI3K pathway, which binds to and degrades p53. In this study, we aimed to clarify the prognostic significance of PIK3CA and MDM2 expression, and potential therapeutic effect of a dual inhibition of the PI3K pathway and MDM2.
cDNA expression was evaluated by using microarray data using 75 samples of CCOC. DS-7423 (dual inhibitor of pan-PI3K and mTOR) and RG7112 (MDM2 inhibitor) were used on CCOC cell lines to evaluate cell proliferation, expression level of MDM2 related proteins, and apoptosis by MTT assay, western blotting, and flow cytometry. DS-7423 (3 mg/kg) and/or RG7112 (50 mg/kg) were orally administrated every day for three weeks, and the anti-tumor effect was evaluated using tumor xenografts, along with immunohistochemistry.
Tumors with high expression of both PIK3CA and MDM2 showed significantly worse prognosis in expression array of 71 CCOCs (P = 0.013). Dual inhibition of the PI3K pathway by DS-7423 and MDM2 by RG7112 showed synergistic anti-proliferative effect in 4 CCOC cell lines without TP53 mutations. The combination therapy more robustly induced pro-apoptotic proteins (PUMA and cleaved PARP) with increase of sub G1 population and apoptotic cells, compared with either single agent alone. The combination therapy significantly reduced tumor volume in mice (P < 0.001 in OVISE, and P = 0.038 in RMG-I) without severe body weight loss. Immunohistochemistry from the xenograft tumors showed that the combination treatment significantly reduced vascularity and cell proliferation, with an increase of apoptotic cell death.
A combination therapy targeting the PI3K pathway and MDM2 might be a promising therapeutic strategy in CCOC.
PI3K 通路信号已成为透明细胞卵巢癌 (CCOC) 中分子靶点的研究热点。MDM2 是 PI3K 通路中 AKT 的效应物之一，可与 p53 结合并使其降解。本研究旨在阐明 PIK3CA 和 MDM2 表达的预后意义，以及双重抑制 PI3K 通路和 MDM2 的潜在治疗效果。
使用 75 例 CCOC 的微阵列数据评估 cDNA 表达。在 CCOC 细胞系中使用 DS-7423（泛 PI3K 和 mTOR 的双重抑制剂）和 RG7112（MDM2 抑制剂）评估细胞增殖、MDM2 相关蛋白的表达水平以及 MTT 测定、Western blot 和流式细胞术检测的细胞凋亡。每天口服 DS-7423（3mg/kg）和/或 RG7112（50mg/kg），连续三周，通过肿瘤异种移植和免疫组织化学评估抗肿瘤效果。
在 71 例 CCOC 的表达阵列中，PIK3CA 和 MDM2 均高表达的肿瘤预后明显较差（P=0.013）。DS-7423 双重抑制 PI3K 通路和 RG7112 抑制 MDM2 在没有 TP53 突变的 4 种 CCOC 细胞系中表现出协同的抗增殖作用。与单药治疗相比，联合治疗更能诱导促凋亡蛋白（PUMA 和 cleaved PARP），增加亚 G1 期细胞和凋亡细胞。联合治疗显著降低了小鼠的肿瘤体积（OVISE 中 P<0.001，RMG-I 中 P=0.038），且无明显体重减轻。异种移植瘤的免疫组化显示，联合治疗可显著降低血管生成和细胞增殖，增加细胞凋亡。
针对 PI3K 通路和 MDM2 的联合治疗可能是 CCOC 有前途的治疗策略。
