Glycosylation-dependent mechanisms regulating ovarian tumor cell survival

糖基化依赖性调节卵巢肿瘤细胞存活的机制

• 批准号: 9042398
• 负责人: Susan L Bellis
• 金额: $ 27.93万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-05-15 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9042398
• 关键词: Acute; Animal Model; Apoptosis; Apoptotic; Ascites; Automobile Driving; Binding; Biological Response Modifiers; Biology; CD95 Antigens; Cancer Patient; Cancer cell line; Cell Death; Cell Survival; Cell surface; Cells; Cessation of life; Charge; Cisplatin; Clinical; Cytoprotection; Disease; Enzymes; Epithelial ovarian cancer; Epithelium; Equilibrium; Event; Galactose Binding Lectin; Galectin 3; Greater sac of peritoneum; Growth; Gynecologic; Health; Human; Immune; Immunocompetent; Immunologic Surveillance; Immunotherapy; Implant; Incubated; Infiltration; Inflammatory; Integrins; Intervention; Knowledge; Ligands; Link; Liquid substance; Malignant Neoplasms; Malignant neoplasm of ovary; Mediating; Minor; Molecular; Monitor; Mus; Neoplasm Metastasis; Ovarian; Papillary; Pathogenesis; Pathway interactions; Patients; Peritoneal; Pharmaceutical Preparations; Phenotype; Platinum; Polysaccharides; Prognostic Marker; Proteins; RNA Interference; Receptor Signaling; Recurrence; Research; Resistance; Role; ST6Gal I; Serous Cystadenocarcinoma; Sialic Acids; Sialyltransferases; Signal Transduction; Sorting - Cell Movement; Stimulus; Surface; TNF gene; TNFRSF1A gene; Therapeutic; Time; Tumor Biology; Tumor Cell Biology; Tumor Necrosis Factor Ligand Superfamily Member 6; Up-Regulation; Work; base; cancer cell; cancer survival; cell behavior; cell type; chemotherapy; cytokine; cytotoxic; glycosylation; glycosyltransferase; in vivo; innovation; knock-down; neoplastic cell; novel; ovarian neoplasm; overexpression; patient biomarkers; prevent; prognostic; receptor; receptor function; receptor internalization; response; sialylation; sugar; therapeutic target; tumor; tumor growth; tumor microenvironment; tumor progression

DESCRIPTION (provided by applicant): An altered profile of surface glycans is a well-known feature of tumor cells; however the molecular mechanisms by which specific glycans and associated glycosyltransferases regulate tumor cell behavior remain elusive. Work from our group has determined that the ST6Gal-I sialyltransferase endows ovarian cancer (OC) cells with the ability to avoid apoptosis induced by multiple stimuli including galectins, death receptor activators and chemotherapeutic drugs. In this proposal we show for the first time that ST6Gal-I protein is upregulated in the great majority of human ovarian tumors, including the lethal papillary serous adenocarcinoma subtype. Upregulation of ST6Gal-I correspondingly causes hypersialylation of selected receptors including the ¿1 integrin, Fas and TNFR1. In paradigm-shifting mechanistic studies, we find that ST6Gal-I-mediated sialylation of Fas and TNFR1 prevents receptor internalization, causing a shift in the signaling of these receptors toward survival rather than apoptosis. Additionally, ST6Gal-I activity confers resistance to apoptotic galectin-3 and the chemotherapeutic, cisplatin. The central hypothesis of this proposal is that ST6Gal-I overexpression underlies two crucial factors contributing to OC lethality: tumor cell resistance to platinum-based chemotherapy (Aim 1), and OC cell protection against immune stimuli within the peritoneal tumor microenvironment (Aim 2), which is rich in gal-3 as well as ligands for Fas and TNFR1. Preliminary studies show that ST6Gal-I promotes OC cell survival within patient peritoneal ascites fluid; this finding is significant in that OC cells metastasize va peritoneal transit. AIM 1: ST6Gal-I-mediated receptor sialylation in chemoresistance. We will define molecular mechanisms responsible for ST6Gal-I's role in cisplatin resistance, and determine whether receptor sialylation controls chemoresistance within the intact tumor microenvironment. Efficacy of cisplatin treatment will be evaluated for orthotopic tumors established in mice from OC cells with differential ST6Gal-I expression, and in vivo delivery of RNAi will be used to implement therapeutic knockdown of ST6Gal-I to restore cisplatin sensitivity. ST6Gal-I will be quantified in chemosensitive vs. chemoresistant human tumors to assess its prognostic potential. AIM 2: Contribution of ST6Gal-I to tumor cell survival within the peritoneal microenvironment Mechanisms underlying ST6Gal-I-dependent OC cell survival within ascites will be elucidated, with a focus on gal-3/ ¿1 integrin, FasL/Fas, and TNF?/TNFR1 interactions. ST6Gal-I-mediated protection of OC cells from cytotoxic immune cells will be examined, and human ovarian tumors screened for an association between ST6Gal-I and immune cell infiltration. The growth of orthotopic tumors +/- ST6Gal-I will be monitored in immunocompetent mice. The studies will have impact by showing that ST6Gal-I is a master regulatory molecule controlling tumor/ microenvironmental interactions that regulate the balance between elimination vs. persistence of OC cells that drive tumor recurrence. Innovation lies in the elucidation of: (1) novel glycosylation-dependent tumor mechanisms, and (2) a new molecular player in OC pathogenesis and biomarker for patient chemoresistance.

描述（由申请人提供）：表面聚糖的改变是肿瘤细胞的一个众所周知的特征；然而，特定的聚糖和相关的糖基转移酶调节肿瘤细胞行为的分子机制仍然是难以捉摸的。我们小组的工作已经确定，ST6Gal-I唾液转移酶赋予卵巢癌（OC）细胞避免多种刺激（包括凝集素、死亡受体激活剂和化疗药物）诱导的凋亡的能力。在这项研究中，我们首次发现st6gal - 1蛋白在绝大多数人类卵巢肿瘤中上调，包括致死性乳头状浆液腺癌亚型。ST6Gal-I的上调相应导致特定受体的高唾液化，包括¿1整合素、Fas和TNFR1。在范式转移机制研究中，我们发现st6gal - i介导的Fas和TNFR1唾液化阻止受体内化，导致这些受体的信号传导向生存而不是凋亡转变。此外，st6gal - 1活性赋予对凋亡的半乳糖凝集素-3和化疗顺铂的抗性。该建议的中心假设是，st6gal - 1过表达是导致OC致死率的两个关键因素的基础：肿瘤细胞对铂类化疗的耐药性（Aim 1），以及OC细胞对腹膜肿瘤微环境中免疫刺激的保护（Aim 2），腹膜肿瘤微环境富含gal-3以及Fas和TNFR1的配体。初步研究表明，ST6Gal-I可促进患者腹膜腹水中OC细胞的存活；这一发现对于卵巢癌细胞通过腹膜转移具有重要意义。目的1:st6gal - i介导的受体唾液化在化学耐药中的作用。我们将确定ST6Gal-I在顺铂耐药中的作用的分子机制，并确定受体唾液化是否在完整的肿瘤微环境中控制化疗耐药。对于ST6Gal-I表达差异的OC细胞在小鼠体内建立的原位肿瘤，将评估顺铂治疗的疗效，并使用体内递送RNAi实现治疗性敲低ST6Gal-I以恢复顺铂敏感性。st6gal - 1将在化疗敏感和化疗耐药的人类肿瘤中进行量化，以评估其预后潜力。目的2:ST6Gal-I对腹膜微环境中肿瘤细胞存活的作用将阐明腹水中ST6Gal-I依赖性OC细胞存活的机制，重点是gal-3/¿1整合素、FasL/Fas和TNF？/ TNFR1交互。将研究ST6Gal-I介导的OC细胞免受细胞毒性免疫细胞的保护，并筛选人类卵巢肿瘤中ST6Gal-I与免疫细胞浸润之间的关联。在免疫功能正常的小鼠中监测原位肿瘤+/- ST6Gal-I的生长。这些研究将产生影响，表明ST6Gal-I是控制肿瘤/微环境相互作用的主要调节分子，调节驱动肿瘤复发的OC细胞消除与持续之间的平衡。创新在于阐明：(1)新的糖基化依赖性肿瘤机制；(2)OC发病机制的新分子参与者和患者化疗耐药的生物标志物。