C9orf142 通过转录激活 MTBP 驱动三阴性乳腺癌的进展和对 CDK4/6 抑制剂的耐药性。

C9orf142 transcriptionally activates MTBP to drive progression and resistance to CDK4/6 inhibitor in triple-negative breast cancer.

机构信息

Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai, China.

Cancer Institute, Shanghai Medical College, Fudan University, Shanghai, China.

出版信息

Clin Transl Med. 2023 Nov;13(11):e1480. doi: 10.1002/ctm2.1480.

DOI:10.1002/ctm2.1480

PMID:38009308

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10679971/

Abstract

BACKGROUND

Triple-negative breast cancer (TNBC) presents the most challenging subtype of all breast cancers because of its aggressive clinical phenotypes and absence of viable therapy targets. In order to identify effective molecular targets for treating patients with TNBC, we conducted an integration analysis of our recently published TNBC dataset of quantitative proteomics and RNA-Sequencing, and found the abnormal upregulation of chromosome 9 open reading frame 142 (C9orf142) in TNBC. However, the functional roles of C9orf142 in TNBC are unclear.

METHODS

In vitro and in vivo functional experiments were performed to assess potential roles of C9orf142 in TNBC. Immunoblotting, real-time quantitative polymerase chain reaction (RT-qPCR), and immunofluorescent staining were used to investigate the expression levels of C9orf142 and its downstream molecules. The molecular mechanisms underlying C9orf142-regulated mouse double minute 2 (MDM2)-binding protein (MTBP) were determined by chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays.

RESULTS

In TNBC tissues and metastatic lymph nodes, we observed that C9orf142 exhibited abnormal up-regulation, and its elevated expression was indicative of unfavorable prognosis for TNBC patients. Both in vitro and in vivo functional experiments demonstrated that C9orf142 accelerated TNBC growth and metastasis. Further mechanism exploration revealed that C9orf142 transcriptionally activated MTBP, thereby regulating its downstream MDM2/p53/p21 signaling axis and the transition of cell cycle from G1 to S phase. Functional rescue experiment demonstrated that knockdown of MTBP attenuated C9orf142-mediated tumour growth and metastasis. Furthermore, depletion of C9orf142 remarkably increased the responsiveness of TNBC cells to CDK4/6 inhibitor abemaciclib.

CONCLUSIONS

Together, these findings unveil a previously unrecognized effect of C9orf142 in TNBC progression and responsiveness to CDK4/6 inhibitor, and emphasize C9orf142 as a promising intervention target for TNBC treatment.

摘要

背景

三阴性乳腺癌（TNBC）是所有乳腺癌中最具挑战性的亚型，因为其具有侵袭性的临床表型和缺乏可行的治疗靶点。为了确定治疗 TNBC 患者的有效分子靶标，我们对我们最近发表的 TNBC 定量蛋白质组学和 RNA 测序数据集进行了整合分析，发现 TNBC 中染色体 9 开放阅读框 142（C9orf142）异常上调。然而，C9orf142 在 TNBC 中的功能作用尚不清楚。

方法

进行体外和体内功能实验，以评估 C9orf142 在 TNBC 中的潜在作用。免疫印迹、实时定量聚合酶链反应（RT-qPCR）和免疫荧光染色用于研究 C9orf142 及其下游分子的表达水平。通过染色质免疫沉淀（ChIP）和双荧光素酶报告基因测定确定 C9orf142 调节的双微体 2（MDM2）结合蛋白（MTBP）的分子机制。

结果

在 TNBC 组织和转移性淋巴结中，我们观察到 C9orf142 异常上调，其高表达提示 TNBC 患者预后不良。体外和体内功能实验均表明 C9orf142 加速了 TNBC 的生长和转移。进一步的机制探索表明，C9orf142 转录激活 MTBP，从而调节其下游 MDM2/p53/p21 信号通路和细胞周期从 G1 期向 S 期的转变。功能挽救实验表明，MTBP 的敲低减弱了 C9orf142 介导的肿瘤生长和转移。此外，C9orf142 的耗竭显著增加了 TNBC 细胞对 CDK4/6 抑制剂 abemaciclib 的反应性。