Kang Wei, Zhang Jinglin, Huang Tingting, Zhou Yuhang, Wong Chi Chun, Chan Ronald C K, Dong Yujuan, Wu Feng, Zhang Bin, Wu William K K, Chan Michael W Y, Cheng Alfred S L, Yu Jun, Wong Nathalie, Lo Kwok Wai, To Ka Fai
Department of Anatomical and Cellular Pathology, State Key Laboratory of Translational Oncology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR, PR China.
Institute of Digestive Disease, State Key Laboratory of Digestive Disease, The Chinese University of Hong Kong, Hong Kong SAR, PR China.
Oncogene. 2021 Mar;40(9):1578-1594. doi: 10.1038/s41388-020-01579-3. Epub 2021 Jan 15.
Aberrant Notch activation has been implicated in multiple malignancies and the identification of NOTCH receptors and related pathways is critical for targeted therapy. In this study, we aim to delineate the most prominent dysregulated NOTCH receptor and comprehensively reveal its deregulation in gastric cancer (GC). In the four Notch members, NOTCH3 was found uniformly upregulated and associated with poor clinical outcomes in multiple GC datasets. siRNA-mediated NOTCH3 knockdown demonstrated antitumor effects by suppressing cell proliferation, inhibiting monolayer formation, and impairing cell invasion abilities. Its depletion also induced early and late apoptosis. NOTCH3 was confirmed to be a direct target of two tumor suppressor microRNAs (miRNAs), namely miR-491-5p and miR-875-5p. The activation of NOTCH3 is partly due to the silence of these two miRNAs. Through RNA-seq profiling and functional validation, PHLDB2 was identified as a potent functional downstream modulator for NOTCH3 in gastric carcinogenesis. PHLDB2 expression demonstrated a positive correlation with NOTCH3, but was negatively correlated with miR-491-5p. Akt-mTOR was revealed as the downstream signaling of PHLDB2. The NOTCH3-PHLDB2-Akt co-activation was found in 33.7% GC patients and the activation of this axis predicted poor clinical outcome. GC cells treated with siNOTCH3, siPHLDB2, miR-491-5p, miR-875-5p, were more sensitive to Cisplatin and 5-FU. Taken together, the NOTCH3-PHLDB2-Akt cascade plays oncogenic role in gastric carcinogenesis and serves as a therapeutic target. Our study provided insights into Notch-mediated underlying molecular mechanisms and implied translational potential.
异常的Notch激活与多种恶性肿瘤有关，Notch受体及相关信号通路的鉴定对于靶向治疗至关重要。在本研究中，我们旨在确定最显著失调的Notch受体，并全面揭示其在胃癌（GC）中的失调情况。在四种Notch成员中，发现Notch3在多个GC数据集中均呈上调，且与不良临床预后相关。siRNA介导的Notch3敲低通过抑制细胞增殖、抑制单层形成和损害细胞侵袭能力显示出抗肿瘤作用。其缺失还诱导早期和晚期凋亡。Notch3被证实是两种肿瘤抑制性微小RNA（miRNA），即miR-491-5p和miR-875-5p的直接靶点。Notch3的激活部分归因于这两种miRNA的沉默。通过RNA测序分析和功能验证，PHLDB2被确定为胃癌发生过程中Notch3的一个有效的功能性下游调节因子。PHLDB2表达与Notch3呈正相关，但与miR-491-5p呈负相关。Akt-mTOR被揭示为PHLDB2的下游信号。在33.7%的GC患者中发现了Notch3-PHLDB2-Akt共激活，该轴的激活预示着不良临床预后。用siNOTCH3、siPHLDB2、miR-491-5p、miR-875-5p处理的GC细胞对顺铂和5-氟尿嘧啶更敏感。综上所述，Notch3-PHLDB2-Akt级联在胃癌发生中起致癌作用，并可作为治疗靶点。我们的研究为Notch介导的潜在分子机制提供了见解，并暗示了转化潜力。
