Breast Cancer Biomarkers in the KLF4 Signaling pathway

KLF4是一种锌指转录因子，是癌基因和肿瘤抑制因子家族的一部分 基因。项目3表明，KLF4在大多数乳腺癌中表达上调，并显示出 与最近显示其在多能干细胞表型中的作用的研究一致。我们 KLF4通过调控Notch1的转录和功能发挥癌基因的作用 (Ntc1)途径蛋白。此外，KLF4诱导维甲酸受体的表达，其功能类似于 乳腺癌中的肿瘤抑制基因。我们的遗传和药理学研究表明，这两个 KLF4调节的通路是KLF4功能的关键决定因素。使用y-对Ntc1的抑制 分泌酶抑制剂或给予RXR选择性维甲酸有效地阻断转化活性 KLF4在体外或体内的表达。这些效应是KFL4特有的，在对照癌基因中没有观察到。 我们已经证明KLF4和Ntc1是在人类中一致表达的预后因子 乳房肿瘤。我们使用这两种蛋白的抗体作为乳腺癌的联合预后因素。 这些研究表明，KLF4-Ntc1途径活性增加的肿瘤具有临床侵袭性，并且 KLF4和Ntc1抗体可用于评估乳腺癌的预后(目标1)。 而Ntc1通过经典途径(即CSL和MAML1)诱导转化，KLF4 抑制CSL并将Ntc1分流到备用路径。在人乳腺MCF10A中的表达 在3D培养中，KLF4或Ntc1诱导的腺泡成熟受阻。KLF4阻断上皮化 这通常发生在将MCF10A细胞接种到Matrigel层后的第6天。为了改进 小分子的临床前测试我们将使用MCF10A细胞来开发一个模型，在这个模型中，细胞 由Ntc1替代路径转换(目标2)。 抑制Ntc1或促进维甲酸受体信号转导的小分子可阻断KLF4的转化。 应用体外乳腺上皮模型、人乳腺癌异种移植瘤和ErbB2诱导的快速模型 我们开发的乳腺癌，这些小分子将作为抑制剂单独和联合进行测试 KLF4在乳腺癌中的作用(目标3)。在临床试验中，我们将探索维甲酸受体的作用 KLF4-Ntc1通路的信号转导及γ-分泌酶抑制剂的抗肿瘤作用 转移性乳腺癌(目标4)。在疗效试验中，KLF4-Ntc1通路组件将相互关联 通过肿瘤反应或耐药性来确定哪些患者最有可能受益。 与公众健康相关：我们的研究将测试KLF4的两种特定抑制剂是否可以使用 单独或联合治疗乳腺癌以及KLF4-Ntc1通路分析是否可以预测 哪些患者可能复发，哪些患者可能对KLF4-Ntc1抑制剂有反应。

KLF4 is a zinc finger transcription factor and part of a family that includes oncogenes and tumor suppressor genes. Project 3 has shown that KLF4 is upregulated in a majority of breast cancers and shows properties of an oncogene, consistent with recent studies showing its role in the pluripotent stem cell phenotype. We demonstrate that KLF4 functions as an oncogene by regulating the transcription and function of Notchl (Ntc1) pathway proteins. In addition, KLF4 induces expression of retinoid receptors that function similarly to tumor suppressor genes in breast cancer. Our genetic and pharmacologic studies show that these two KLF4-regulated pathways are critical determinants of KLF4 function. Either inhibition of Ntc1 using y- secretase inhibitors or administration of an RXR-selective retinoid efficiently blocked the transforming activity of KLF4 in vitro or in vivo. These effects were KFL4-specific and were not observed for control oncogenes. We have shown that KLF4 and Ntc1 are prognostic factors that are concordantly expressed in human breast tumors. We used antibodies to these two proteins as combination prognostic factors in breast cancer. These studies suggest that tumors with increased KLF4-Ntc1 pathway activity are clinically aggressive, and that KLF4 and Ntc1 antibodies can be use to assess prognosis in breast cancer (Aim 1). Whereas Ntc1 induces transformation through the Classical Pathway (i.e., CSL and MAML1), KLF4 suppresses CSL and shunts Ntc1 to an Alternate Pathway. When expressed in human mammary MCF10A cells, KLF4 or Ntc1 induced a block to acinar maturation in 3D cultures. KLF4 blocked the epithelialization that normally occurs by day 6 following inoculation of MCF10A cells onto a Matrigel layer. For improved preclinical testing of small molecules we will use MCF10A cells to develop a model in which cells are transformed by the Ntc1 Alternate Pathway (Aim 2). Small molecules that inhibit Ntc1 or promote retinoid receptor signaling blocked transformation by KLF4. Using in vitro breast epithelial models, human breast cancer xenografts, and a rapid model of ErbB2-induced breast cancer that we developed, these small molecules will be tested alone and in combination as inhibitors of KLF4 effects in breast cancer (Aim 3). In clinical trials, we will explore the effects of retinoid receptor signaling on the KLF4-Ntc1 pathway and estimate the anti-tumor efficacy of y-secretase inhibitors in metastatic breast cancer (Aim 4). In the efficacy trial, KLF4-Ntc1 pathway components will be correlated with tumor response or resistance to identify which patients are most likely to benefit. Relevance to public health: Our studies will test whether two specific inhibitors of KLF4 can be used alone or in combination for treatment of breast cancer, and whether KLF4-Ntc1 pathway analysis can predict which patients are likely to have recurrence/relapseand which patients may respond to KLF4-Ntc1 inhibitors.