Nuclear Factor-kappaB in Ovarian Cancer

卵巢癌中的核因子-kappaB

• 批准号: 8552955
• 负责人: Christina Annunziata
• 金额: $ 82.13万
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8552955
• 关键词: Adhesions; Affect; Aggressive behavior; B-Cell Lymphomas; Biological; Biological Markers; Cancer cell line; Cell Survival; Databases; Dependence; Diagnosis; Disease; Family; Gene Expression; Gene Expression Profile; Gene Targeting; Genes; Goals; Growth; In Vitro; Laboratories; Lymphoid; Lymphoma; Malignant Neoplasms; Malignant neoplasm of ovary; Molecular Structure; Multiple Myeloma; Mutation; NF-kappa B; Nuclear; Outcome; Pathogenesis; Pathway interactions; Patients; Pattern; Phosphorylation; Phosphotransferases; Play; Property; Proteins; RNA Interference; Relative (related person); Research; Signal Transduction; Solid Neoplasm; Specificity; TNFRSF5 gene; Therapeutic Intervention; Tissues; Toxic effect; Woman; Work; base; cancer cell; caspase-8; cytokine; development of lymphoid malignancy; genetic manipulation; inhibitor/antagonist; insight; multicatalytic endopeptidase complex; novel; overexpression; peptide A; prognostic; small hairpin RNA; small molecule; therapeutic target; transcription factor; tumor

The NF-kB pathway promotes survival of cancer cells. My research in ovarian cancer began with characterizing the activation state and biological relevance of NF-kB in this disease. The NF-kB family of transcription factors is ubiquitously expressed. NF-kB signaling has been implicated in ovarian cancer, but the significance and mechanism of NF-kB signaling in ovarian cancer is unknown. There is precedent to propose that NF-kB is a critical signaling mechanism in cancer. I initially hypothesized that the NF-kB pathway is over-activated in ovarian cancers with more aggressive behavior. The NF-kB pathway was implicated in ovarian cancer proliferation and cytokine secretion in vitro, and contributed to chemoresistance of ovarian cancer cell lines. I therefore sought to determine the expression patterns and prognostic associations of NF-kB pathway proteins in primary ovarian cancer tissues. I demonstrated that overexpression of the NF-kB subunit p50 at diagnosis conveyed poor outcome in these patients. The biological relevance of NF-kB in ovarian cancer was established in my laboratory. Having demonstrated the coordinate presence of NF-kB machinery in ovarian cancers, I sought to modulate its activity. Inhibitors of NF-kB (IkBs) are tagged for degradation through the proteasome upon specific inducible phosphorylation by IkB kinases (IKKs). Therefore, targeted inhibition of IKKs could isolate NF-kB as a mechanism for ovarian cancer pathogenesis. A subset of ovarian cancer cell lines was affected by inhibition of IKKb in properties of growth, adhesion, invasion and cytokine secretion. I developed a gene expression signature of IKKb signaling in ovarian cancer using both pharmacologic and genetic manipulation of IKKb. This signature gave insight into the results of NF-kB in ovarian cancer, based on known functions of the ovarian cancer-specific target genes, and allowed me to probe established ovarian cancer databases in order to estimate the relative impact of NF-kB signaling on the survival of women with ovarian cancer. Higher NF-kB activity conveyed a worse outcome, suggesting that modulation of IKKb might benefit patients whose tumors showed elevated target gene expression. A key discovery from this work was the tissue specificity of NF-kB signaling. The 9-gene signature experimentally defined in ovarian cancer was completely different from the 11 genes I previously identified in multiple myeloma. We performed a global RNAi sensitization screen in combination with a small molecule IKKb inhibitor looking for interactions that enhanced toxicity. Our screen identified caspase 8. A similar screen in lymphoma, performed by our collaborators, found IKKa. Therefore, I hypothesize that caspase 8 is more active in ovarian cancer, in contrast to B cell lymphomas.I validated the cooperativity of IKKb and caspase 8 using a sub-lethal concentration of IKKb inhibitor with caspase 8 shRNA. I began to examine the context of caspase 8 function in ovarian cancer. First, I asked whether caspase 8 enzymatic activity was required for synergy with IKKb. A peptide inhibitor of caspase 8 cleavage activity did not affect ovarian cancer cell viability in the presence of IKKb inhibitor, indicating that this function of caspase 8 was not necessary for its cooperation with IKKb. This finding suggests that caspase 8 plays a different function to activate NF-kB in ovarian cancer.

核因子-kB途径促进癌细胞存活。我对卵巢癌的研究始于确定核因子-kB在这种疾病中的激活状态和生物学相关性。核转录因子-kB家族广泛表达。核因子-kB信号与卵巢癌有关，但核因子-kB信号在卵巢癌中的意义和作用机制尚不清楚。有先例表明，核因子-kB在癌症中是一种关键的信号机制。我最初的假设是，在有更多攻击性行为的卵巢癌中，核因子-kB途径被过度激活。在体外，核因子-kB途径参与了卵巢癌细胞的增殖和细胞因子的分泌，并参与了卵巢癌细胞的化疗耐药。因此，我试图确定核因子-kB途径蛋白在原发卵巢癌组织中的表达模式和预后相关性。我证明了核因子-kB亚单位p50在诊断时的过度表达在这些患者中传达了不良的结局。核因子-kB在卵巢癌中的生物学相关性是在我的实验室建立的。在证明了核因子-kB机制在卵巢癌中的协同存在后，我试图调节它的活动。核因子-kB的抑制物(IkB)被标记为通过蛋白酶体被IKB激酶(IKK)特异地诱导磷酸化而降解。因此，靶向抑制IKKS可以分离出作为卵巢癌发病机制的核因子-kB。抑制IKKB对卵巢癌细胞生长、黏附、侵袭和细胞因子分泌的影响。我利用IKKB的药理学和遗传操作，开发了卵巢癌中IKKB信号的基因表达特征。这一信号使我深入了解了基于卵巢癌特定靶基因已知功能的核因子-kB在卵巢癌中的结果，并使我能够探索已建立的卵巢癌数据库，以评估核因子-kB信号对卵巢癌女性患者生存的相对影响。更高的核因子-kB活性意味着更糟糕的结果，这表明IKKB的调节可能有利于肿瘤显示出靶基因表达升高的患者。这项工作的一个关键发现是核因子-kB信号的组织特异性。卵巢癌实验中定义的9个基因特征与我之前在多发性骨髓瘤中确定的11个基因完全不同。我们结合小分子IKKB抑制剂进行了全球RNAi敏化筛选，以寻找增强毒性的相互作用。我们的筛查发现了caspase 8。我们的合作者在淋巴瘤中进行的类似筛查发现了Ikka。因此，我假设caspase 8在卵巢癌中更活跃，而不是B细胞淋巴瘤。我用亚致死浓度的IKKB抑制剂和caspase 8 shRNA验证了IKKB和caspase 8的协同作用。我开始研究caspase 8在卵巢癌中的功能。首先，我问与IKKB的协同作用是否需要caspase 8的酶活性。在IKKB抑制剂存在的情况下，caspase 8裂解活性的多肽抑制剂不影响卵巢癌细胞的活力，表明caspase 8的这一功能不是其与IKKB合作所必需的。这一发现表明，在卵巢癌中，caspase 8在激活核因子-kB方面发挥了不同的功能。