SCAMP3 as a regulator of EGFR/STAT3 axis in triple-negative breast cancer

项目摘要 这项提议将调查导致最大规模的 侵袭性和转移性乳腺癌。三阴性乳腺癌(TNBC)的特点是 缺乏激素受体(雌激素和孕激素)和HER2的表达，并解释了大约 20%的乳腺癌患者。由于其异质性和缺乏明确的特定分子靶点，TNBC 治疗仍然具有挑战性。因此，本研究试图阐明分泌载体的分子作用-- 相关膜蛋白3(SCAMP3)在TNBC发病机制中的作用，目的是开发新的治疗方法 这将提高患者的存活率。最近，SCAMP3被发现过度表达并与 肝细胞癌、黑色素瘤、胶质瘤和乳腺癌预后不良，提示 SCAMP3在肿瘤发生中起关键作用。然而，SCAMP3促进TNBC的分子机制 人们对进展知之甚少。SCAMP3是表皮生长因子受体(EGFR)转运的调节因子 在促进受体循环的内体膜内。EGFR介导的内吞作用是一种机制 肿瘤相关信号蛋白的运输，如信号转导和转录激活因子3 (统计数据3)。EGFR和STAT3与TNBC的增殖、侵袭、转移和癌症有关 干细胞(CSC)维护。我们的目标是确定SCAMP3促进 并确定SCAMP3/EGFR和STAT3信号通路之间的相互作用。我们 假设：1)SCAMP3/EGFR介导的内吞作用调节STAT3的激活。2)SCAMP3 信号通路通过调节EGFR/STAT3促进和维持TNBC的干性，以及3) SCAMP3参与TNBC肿瘤的形成和转移。为了检验这些假设，我们提出了 目的：1)阐明SCAMP3在STAT3激活中的作用机制；2)明确SCAMP3在STAT3中的作用 SCAMP3在TNBC和CSCs中通过STAT3的调节作用：2A)阐明 2b)探讨SCAMP3在肿瘤发生和发展中的作用。 转移。我们提出了监测EGFR和STAT3内化、STAT3DNA结合的实验 活性和转录活性。我们将确定维持癌症干性的相关驱动基因 使用RNAseq过表达SCAMP3细胞，这将在患者样本中得到证实。这些研究有 有可能迅速转化为临床，并显著减少相关死亡的发生率和数量 致TNBC。

Project Summary This proposal will investigate the molecular drivers that contribute to the progression of one of the most aggressive and metastatic types of breast cancer. Triple Negative Breast Cancer (TNBC) is characterized by the lack of hormone receptors (estrogen and progesterone) and HER2 expression and accounts for approximately 20% of all breast cancers. Due to its heterogeneity and dearth of defined specific molecular targets, TNBC treatment remains challenging. Accordingly, this study seeks to elucidate the molecular role of secretory carrier- associated membrane protein 3 (SCAMP3) on TNBC pathogenesis, with the goal of developing new therapies that will improve the survival rate of patients. Recently, SCAMP3 has been found overexpressed and associated with poor prognosis in hepatocellular carcinoma, melanoma, glioma, and breast cancer, suggesting that SCAMP3 has a key role in oncogenesis. However, the molecular mechanisms of how SCAMP3 promotes TNBC progression are poorly understood. SCAMP3 is a regulator of epidermal growth factor receptor (EGFR) trafficking within endosomal membranes promoting receptor recycling. EGFR mediated endocytosis is a mechanism of transport of cancer-associated signaling proteins, such as signal transducer and activator of transcription 3 (STAT3). EGFR and STAT3 have been associated with TNBC proliferation, invasion, metastasis, and cancer stem cell (CSC) maintenance. Our objectives are to determine the mechanisms by which SCAMP3 promotes TNBC progression and determine the interplay between SCAMP3/EGFR and STAT3 signaling pathways. We hypothesize that: 1) SCAMP3/EGFR mediated endocytosis regulates the activation of STAT3. 2) SCAMP3 signaling pathway promotes and maintains TNBC stemness via the modulation of EGFR/STAT3, and 3) SCAMP3 contributes to TNBC tumor formation and metastasis. To test these hypotheses, we propose the following aims: 1) To elucidate the mechanism of action of SCAMP3 on STAT3 activation; 2) Define the role of SCAMP3 in TNBC and CSCs regulation via STAT3 modulation: 2a) To elucidate the molecular mechanisms of SCAMP3 in CSCs maintenance in vitro; 2b) To investigate the effect of SCAMP3 in tumorigenesis and metastasis. We propose experiments that will monitor EGFR and STAT3 internalization, STAT3 DNA-binding activity, and transcriptional activity. We will identify the relevant driver genes that maintain cancer stemness in SCAMP3 overexpressing cells using RNAseq, which will be confirmed in patient samples. The studies have the potential to be rapidly translated to the clinic and significantly reduce the incidence and number of deaths related to TNBC.