Tribbles Homolog 3 Involved in Radiation Response of Triple Negative Breast Cancer Cells by Regulating Notch1 Activation
Tribbles Homolog 3 Involved in Radiation Response of Triple Negative Breast Cancer Cells by Regulating Notch1 Activation
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DOI：
10.3390/cancers11020127
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发表时间：
2019-02-01
期刊：
影响因子：
5.2
通讯作者：
Chang, Wen-Wei
中科院分区：
文献类型：
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作者：
Lee, Yueh-Chun;Wang, Wen-Ling;Chang, Wen-Wei
乳癌是台湾女性最常见的癌症，肿块切除后放射治疗是此病的治疗策略之一。虽然放疗显著提高了乳腺癌患者的10年总生存率，但局部复发率约为10%，三阴性乳腺癌(TNBCs)具有较高的复发风险。本文旨在了解乳腺癌放射抵抗的机制，为乳腺癌放射治疗增敏新的治疗方法的发展提供帮助。Tribble Homolog 3(TRIB3)是一种假激酶蛋白，在细胞内作为蛋白质支架发挥作用。据报道，在接受放射治疗的乳腺癌患者中，TRIB3的高表达是一个不良的预后因素。在本研究中，我们研究了TRIB3在TNBC细胞辐射反应中的作用。我们首次发现在两个抗辐射的TNBC细胞中，TRIB3的表达和Notch1的激活以及Notch1靶基因的表达增加。在抗辐射的MDA-MB-231 TNBC细胞中，TRIB3的敲除降低了Notch1的激活，以及CD24-CD44(+)癌症干细胞的数量，并使细胞对放射治疗敏感。TRIB3基因敲除对细胞自我更新或辐射抗性的抑制作用可被强制表达的Notch胞内域逆转。我们还观察到TRIB3基因被敲除后，耐辐射的MDA-MB-231细胞的生长受到抑制，并在G(0)/G(1)期积累细胞。通过免疫沉淀和质谱分析，我们发现BCL2相关转录因子1(BCLAF1)、BCL2相互作用蛋白1(BNIP1)或DEAD-box解旋酶5(DDX5)是可能的TRIB3相互作用蛋白，免疫沉淀结果也证实这些蛋白在辐射抗性的MDA-MB-231细胞中与TRIB3相互作用。结论：TRIB3在抗辐射的TNBC细胞中的表达参与了Notch1的激活，靶向表达TRIB3可能是使TNBC细胞对放射治疗增敏的一种策略。
Breast cancer is the most common cancer for women in Taiwan and post-lumpectomy radiotherapy is one of the therapeutic strategies for this malignancy. Although the 10-year overall survival of breast cancer patients is greatly improved by radiotherapy, the locoregional recurrence is around 10% and triple negative breast cancers (TNBCs) are at a high risk for relapse. The aim of this paper is to understand the mechanisms of radioresistance in breast cancers which may facilitate the development of new treatments in sensitizing breast cancer toward radiation therapy. Tribbles homolog 3 (TRIB3) is a pseudokinase protein and known to function as a protein scaffold within cells. It has been reported that higher TRIB3 expression is a poor prognostic factor in breast cancer patients with radiotherapy. In this study, we investigate the involvement of TRIB3 in the radiation response of TNBC cells. We first found that the expression of TRIB3 and the activation of Notch1, as well as Notch1 target genes, increased in two radioresistant TNBC cells. Knockdown of TRIB3 in radioresistant MDA-MB-231 TNBC cells decreased Notch1 activation, as well as the CD24-CD44(+) cancer stem cell population, and sensitized cells toward radiation treatment. The inhibitory effects of TRIB3 knockdown in self-renewal or radioresistance could be reversed by forced expression of the Notch intracellular domain. We also observed an inhibition in cell growth and accumulated cells in the G(0)/G(1) phase in radioresistant MDA-MB-231 cells after knockdown of TRIB3. With immunoprecipitation and mass spectrometry analysis, we found that, BCL2-associated transcription factor 1 (BCLAF1), BCL2 interacting protein 1 (BNIP1), or DEAD-box helicase 5 (DDX5) were the possible TRIB3 interacting proteins and immunoprecipitation data also confirmed that these proteins interacted with TRIB3 in radioresistant MDA-MB-231 cells. In conclusion, the expression of TRIB3 in radioresistant TNBC cells participated in Notch1 activation and targeted TRIB3 expression may be a strategy to sensitize TNBC cells toward radiation therapy.