Integral membrane protein 2A inhibits cell growth in human breast cancer via enhancing autophagy induction
Integral membrane protein 2A inhibits cell growth in human breast cancer via enhancing autophagy induction
复制标题
整合膜蛋白2A通过增强自噬诱导抑制人乳腺癌细胞生长
DOI：
10.1186/s12964-019-0422-7
复制
发表时间：
2019-08-22
影响因子：
8.4
通讯作者：
Tang, Jingfeng
中科院分区：
文献类型：
--
作者：
Zhou, Cefan;Wang, Ming;Tang, Jingfeng
背景乳腺癌是一种威胁女性生命的疾病，是女性死亡的主要原因，给预后和治疗带来了巨大的挑战。ITM2A是BRICHOS超家族的成员，被认为具有伴侣功能。ITM2A与卵巢癌的发生、发展密切相关。方法采用实时荧光定量聚合酶链反应（qRT-PCR）、免疫印迹法和免疫组织化学染色方法检测ITM2A在乳腺癌中的表达水平。通过Kaplan-Meier分析评价患者总生存期与ITM2A表达水平。采用MTT法、EdU掺入法和集落形成法检测ITM2A对乳腺癌细胞增殖的影响。共聚焦显微镜下自噬流量检测和透射电镜下自噬空泡观察，探讨自噬作用。采用体外激酶试验研究HUNK对ITM 2A的磷酸化修饰。结果我们的数据显示，人乳腺癌组织和细胞系中完整膜蛋白2A（ITM 2A）的表达显着下调。Kaplan-Meier分析表明，ITM2A表达降低的患者总体生存率较差，且表达与年龄、孕激素受体状态、TNM分期和肿瘤分期显著相关。ITM2A过表达显著抑制乳腺癌细胞的增殖。通过研究人乳腺癌SKBR-3细胞中的几种自噬标志物和事件，我们进一步证明了ITM2A是一种新的自噬正调控因子，通过mTOR依赖的方式。此外，我们发现，ITM2A磷酸化T35由HUNK，丝氨酸/苏氨酸激酶显着相关的人乳腺癌的总生存率和HER2诱导的乳腺tumorigenes.ConclusionOur研究提供的证据表明，ITM2A功能作为一种新的预后标志物，并代表一个潜在的治疗靶点。
BackgroundBreast cancer is a life-threatening disease in females and the leading cause of mortality among the female population, presenting huge challenges for prognosis and treatment. ITM2A is a member of the BRICHOS superfamily, which are thought to have a chaperone function. ITM2A has been identified to related to ovarian cancer progress recently. However, the biological role of ITM2A in breast cancer remains largely unclear.MethodsQuantitative real-time polymerase chain reaction (qRT-PCR), western blotting assay and immunohistochemistry staining were used to analyzed the expression level of ITM2A. The patient overall survival versus ITM2A expression level was evaluated by Kaplan-Meier analysis. MTT assay, EdU incorporation assay and colony formation assay were used to evaluated the role of ITM2A on breast cancer cell proliferation. Autophagy was explored through autophagic flux detection using a confocal microscope and autophagic vacuoles investigation under a transmission electron microscopy (TEM). In vitro kinase assay was used to investigated the phosphorylation modification of ITM2A by HUNK.ResultsOur data showed that the expression of integral membrane protein 2A (ITM2A) was significantly down-regulated in human breast cancer tissues and cell lines. Kaplan-Meier analysis indicated that patients presenting with reduced ITM2A expression exhibited poor overall survival, and expression significantly correlated with age, progesterone receptor status, TNM classification and tumor stage. ITM2A overexpression significantly inhibited the proliferation of breast cancer cells. By studying several autophagic markers and events in human breast cancer SKBR-3 cells, we further demonstrated that ITM2A is a novel positive regulator of autophagy through an mTOR-dependent manner. Moreover, we found that ITM2A was phosphorylated at T35 by HUNK, a serine/threonine kinase significantly correlated with human breast cancer overall survival and HER2-induced mammary tumorigenesis.ConclusionOur study provided evidence that ITM2A functions as a novel prognostic marker and represents a potential therapeutic target.