PO.ET09.06 · 实验与分子治疗
(Z)-endoxifen 调节雌激素受体和细胞周期信号，在子宫内膜癌模型中与 CDK4/6 抑制产生协同抗增殖效应
(Z)-endoxifen modulates estrogen receptor and cell-cycle signaling to induce synergistic antiproliferative effects with CDK4/6 inhibition in endometrial cancer models
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
背景：子宫内膜癌（EC）仍是一种主要的妇科恶性肿瘤，其部分由异常的雌激素受体（ER）信号驱动。他莫昔芬的活性代谢物 (Z)-endoxifen 表现出双重的 SERM/SERD 样活性，在调节 ER 功能的同时发挥额外的非经典抗增殖作用。理解 (Z)-endoxifen 的作用机制及其与细胞周期调控因子的相互作用，对于优化 EC 的靶向治疗至关重要。本研究考察了 (Z)-endoxifen 单独以及与 CDK4/6 抑制剂 abemaciclib 联合在多种 EC 模型中的分子和功能效应，以明确其机制活性和转化潜力。
方法：对 ER+（Ishikawa、HCI-EC23、患者来源类器官 U1561.005）和 ER 可变（ARK1、ARK2）的 EC 模型给予雌激素（0-10 nM）、(Z)-endoxifen（125 nM-10 μM）或氟维司群（0-2.5 μM）以及 abemaciclib（0-10 μM），作为单药或联合使用。使用基于发光的检测评估细胞存活率。评估剂量反应分析和联合协同作用，以确定内分泌敏感性、ER 依赖性以及下游细胞周期效应。
结果：雌激素在 ER+ 模型中诱导了双相增殖反应，证实了配体驱动的促有丝分裂信号。(Z)-endoxifen 单药在所有细胞系中抑制存活率，显示出优于氟维司群的效力以及不依赖于 ER 表达状态的活性。在机制上，(Z)-endoxifen 消除了雌激素诱导的增殖峰，与 ER 拮抗及潜在的受体降解一致，同时还发挥了提示细胞周期调节的 ER 非依赖性效应。abemaciclib 单药在 ER+ 和 ER− 模型中均抑制存活率，其与 (Z)-endoxifen 的联合产生了强烈的协同活性（Chou-Talalay 联合指数 < 1），包括在 ER 阴性的 ARK2 和 ER+ 的 U1561.005 类器官中。这种协同作用可能源于对 ER 信号和 CDK4/6-cyclin D 调控通路的同时破坏。
结论：(Z)-endoxifen 在 EC 临床前模型中表现出 ER 依赖性和 ER 非依赖性双重活性。观察到其与 CDK4/6 抑制剂联合的协同作用。这些发现拓宽了当前对 (Z)-endoxifen 疗效的理解，并支持进一步探索其在 ER 驱动型和混合表型 EC 中潜在的治疗作用，包括评估不同 ER 表达水平下的反应。
查看英文原文 English abstract
Background: Endometrial cancer (EC) remains a major gynecologic malignancy driven in part by aberrant estrogen receptor (ER) signaling. The active tamoxifen metabolite (Z)-endoxifen exhibits dual SERM/SERD-like activity, modulating ER function while exerting additional noncanonical antiproliferative effects. Understanding (Z)-endoxifen's mechanisms of action and its interaction with cell-cycle regulators is critical to optimizing targeted therapy in EC. This study investigated the molecular and functional effects of (Z)-endoxifen, alone and in combination with the CDK4/6 inhibitor abemaciclib, across diverse EC models to define mechanistic activity and translational potential.
Methods: ER+ (Ishikawa, HCI-EC23, patient derived organoid U1561.005) and ER-variable (ARK1, ARK2) EC models were treated with estrogen (0-10 nM), (Z)-endoxifen (125 nM-10 µM) or fulvestrant (0-2.5 μM), and abemaciclib (0-10 μM), as single agents or in combination. Cell viability was assessed using luminescence-based assays. Dose-response analyses and combinatorial synergy were evaluated to determine endocrine sensitivity, ER dependency, and downstream cell-cycle effects.
Results: Estrogen induced biphasic proliferative responses in ER+ models, confirming ligand-driven mitogenic signaling. (Z)-Endoxifen monotherapy suppressed viability across all cell lines, demonstrating superior potency to fulvestrant and activity independent of ER expression status. Mechanistically, (Z)-endoxifen abrogated estrogen-induced proliferative peaks, consistent with ER antagonism and potential receptor degradation, while also exerting ER-independent effects suggestive of cell-cycle modulation. Abemaciclib monotherapy inhibited viability in both ER+ and ER− models, and its combination with (Z)-endoxifen yielded strong synergistic activity (Chou-Talalay combination index < 1), including in ER-negative ARK2 and the ER+ U1561.005 organoid. This synergy likely arises from concurrent disruption of ER signaling and CDK4/6-cyclin D regulatory pathways.
Conclusions: (Z)-Endoxifen demonstrates dual ER-dependent and ER-independent activity in EC preclinical models. Synergy was observed in combination a CDK 4/6 inhibitor. These findings broaden the current understanding of (Z)-endoxifen's efficacy and support further exploration of its potential therapeutic role in ER-driven and mixed-phenotype EC, including evaluation of responses across ER expression levels.
利益披露 Disclosure
G. Choong,
Atossa Therapeutics Inc ).
X. Hou, None.
S. S. Hammer,
Atossa Therapeutics Inc. Employment, Stock.
S. M. Blackburn,
Atossa Therapeutics Inc Employment, Stock.
J. Weroha,
Atossa Therapeutics Inc ).
S. C. Quay,
Atossa Therapeutics Inc Employment, Stock, CEO, President.