Regulation of Basal-Like and Her2+ Breast Cancer Phenotypes by IKK/NF-kappaB

描述（由申请人提供）：乳腺肿瘤异质性的临床/病理观察现已在基因表达水平上得到证实，具有不同肿瘤亚型的特征。er阴性癌症包括至少两种不同的亚型：Her2+亚型和基底样亚型。基底样乳腺癌表型在绝经前非裔美国人癌症病例中更为普遍。我们的基因表达分析显示，许多基底样乳腺癌表达已知受转录因子NF- B调控的基因。最近有报道称基底样癌表现为PI3K/Akt的激活和p53的缺失。Her2+亚型癌症与一组不同的NF-？b依赖基因来自于基底样细胞。虽然Akt对Her2+细胞的生长和存活至关重要，但我们的研究表明Akt不参与NF-？B在Her2+细胞中，而在基底样细胞中很重要。我们的假设是NF-？B通过不同的机制促进基底样和Her2+乳腺癌的致瘤表型和癌症治疗耐药性，NF-？在这些癌症中B的激活通过不同的途径发生。我们假设不同形式的NF-？B在这两种类型的乳腺癌中被激活导致不同的靶基因表达。此外，我们通过IKK1-mTORC2机制探索了Akt在这些细胞中的控制作用。此外，我们的数据表明，小鼠乳腺肿瘤反映了许多人类肿瘤的表型。因此，我们建议这些动物模型可用于从遗传学上测试IKK/NF-？B通路在肿瘤发生和进展中的作用，并用于阻断NF-？B活化或其他关键调控信号。我们不知道有任何利用基底样癌动物模型来研究IKK/NF-？B在疾病中。有一项非常有限的敲入研究分析了IKK1在Her2+癌症中的参与。药物研究仅限于异种移植物，并且在特定抑制剂方面相当有限，并且没有关注IKK1和IKK2的双重作用。为了验证我们的假设，我们建议：(i)分析基底样癌细胞、动物模型和人体组织，寻找与NF-激活相关的机制。B和靶基因表达，并确定针对这些和其他相关途径的抑制剂的作用，（ii）表征Her2+癌细胞系、动物肿瘤和人类组织的NF-:B激活、靶基因表达和肿瘤表型，以及平行抑制剂研究，以及解决赫赛汀耐药的另一种方法，以及（iii）测试基底样癌和Her2+癌症的动物模型，以了解NF-？B/IKK成分和特定基因靶点对癌症发生和进展的影响。确定IKK、mTOR和EGFR的高度特异性抑制剂是否可以抑制或恢复动物源性肿瘤的生长和/或对化疗的敏感性。这些研究将提供对两种关键乳腺肿瘤亚型的发展和致癌表型的深入了解，并有可能为这些疾病开发新的治疗方案。

DESCRIPTION (provided by applicant): Clinical/pathological observations of breast tumor heterogeneity have now been confirmed at the gene expression level with the characterization of distinct tumor subtypes. ER-negative cancer comprises at least two distinct subtypes: the Her2+ subtype and the basal-like subtype. The basal-like breast cancer phenotype is more prevalent among premenopausal African-American cancer cases. Our gene expression analysis reveals that many basal-like breast cancers express genes that are known to be regulated by the transcription factor NF-?B. Recently it has been reported that basal-like cancers exhibit activation of PI3K/Akt and loss of p53. The Her2+ subtype of cancer is associated with the expression of a distinct set of NF-?B-dependent genes from that found in basal-like. While Akt is critical for growth and survival of Her2+ cells, our work indicates that Akt is not involved in the activation of NF-?B in Her2+ cells while it is important in basal-like cells. --Our hypothesis is that NF-?B contributes to the oncogenic phenotype and cancer therapy resistance in both basal-like and Her2+ breast cancers through different mechanisms, and that NF-?B activation in these cancers occurs by different pathways. We hypothesize that different forms of NF-?B are activated in these two types of breast cancers leading to different target gene expression. Additionally, we explore the control of Akt in these cells through an IKK1-mTORC2 mechanism. Furthermore, our data demonstrate that mouse breast tumors reflect many of the phenotypes of human tumors. Thus, we propose that these animal models can be used to test genetically the involvement of the IKK/NF-?B pathway in tumor initiation and progression, and used for analysis of therapies that block NF-?B activation or other key regulatory signaling. We are unaware of any study utilizing an animal model of basal-like cancer to address a role for IKK/NF-?B in the disease. There is one very limited knock-in study analyzing an involvement of IKK1 in Her2+ cancer. Drug studies are limited to xenografts and are quite limited regarding specific inhibitors, and do not focus on dual roles of IKK1 and IKK2. --To test our hypotheses, we propose to: (i) analyze basal-like cancer cells, animal models, and human tissue for mechanisms associated with the activation of NF-?B and target gene expression, and determine the effects of inhibitors that target these and other relevant pathways, (ii) characterize Her2+ cancer cell lines, animal tumors, and human tissue for activation of NF-:B, target gene expression, and onco-phenotypes, along with parallel inhibitor studies, with an additional approach to address Herceptin resistance, and (iii) test animal models for basal-like and Her2+ cancers for the roles of NF-?B/IKK components and specific gene targets for the development and progression of the cancers. Determine if highly specific inhibitors of IKK, mTOR, and possibly EGFR can suppress or revert growth of animal-derived tumors and/or sensitize to chemotherapy. These studies will provide insight into the development and oncogenic phenotypes of two key breast tumor subtypes and have the potential for the development of new therapeutic options for these diseases. PUBLIC HEALTH RELEVANCE: While activation of the transcription factor NF-?B is associated with hematologic malignancies and with solid tumors, there are only a few studies using specific inhibitors of the NF-?B pathway in animal models of cancer. NF-?B is activated by both IKK1 and IKK2, and no efforts have been directed at blocking total IKK in tumor cells. Additionally, there are no inhibitor studies directed at targeting the ability of IKK to control other key pro-oncogenic pathways (separate from NF-?B). Our effort is directed towards understanding the role of NF-?B in two breast tumor subtypes with poor prognosis: basal-like cancers and Her2/ErbB2+ cancers. Preliminary data indicate that different forms of NF-?B are activated in these cancers leading to the regulation of distinct sets of genes. Interestingly, genes expressed in human basal-like or Her2+ cancers are also expressed in human cancer cell lines and in animal models for these breast cancer subtypes. We will explore the regulatory pathways associated with NF-?B activation and function in these two types of cancer, with additional studies focused on the ability of IKK to control Akt in these cells. Based on encouraging preliminary data, we will utilize genetic models and we will test highly specific inhibitors of IKK1 and IKK2 (key upstream regulators of NF-?B) in cell lines and in animal models to test the involvement of this pathway in controlling oncogenic development/progression and in regulating resistance to key cancer therapeutics. In this regard, we are hopeful that our experiments will provide new therapeutic options for forms of breast cancer with poor outcome. Additionally, our studies will provide unique insight into the functions of different signaling pathways associated with NF-?B in controlling oncogenic phenotypes.