A novel molecular cross-talk driving pancreatic cancer progression

肿瘤细胞在发展过程中不可避免地面临缺氧及其对低氧的适应 应激可促进侵袭性、转移性和耐药表型。因此，理解 低氧适应性反应的分子基础和相关分子靶点的识别 极大地促进了制定有效的癌症管理战略。我们最近提供了 首次有实验证据证明MYB在胰腺癌(PC)中的病理生物学作用。我们的小说初步 现在的研究结果表明：1)myb在低氧细胞存活中的作用；ii)myb对缺氧诱导因子-1α的调节； MYB-HIF-1α相互作用和共定位。在其他新发现中，我们显示了myb与其不同的结合。 低氧条件下的两个靶基因启动子。此外，我们的新数据支持MYB的临床意义。 通过显示它在胰腺肿瘤病例中的广泛表达，这也暗示了它的相关性 随着肿瘤分级的增加和患者生存时间的延长。基于这些令人信服的发现，我们 假设MYB-HIF1α串扰在胰腺癌进展和转移中起重要作用，这将是 在四个具体目标上进行了测试。在目标1中，我们将通过以下方式调查myb和hif-1α之间的监管相互作用 研究缺氧条件下MYB和HIF-1α的协同调节以及两者之间可能存在的相互作用 他们。在目标2中，我们将定义myb和缺氧诱导因子-1α之间的相互作用在其转录中的作用。 重编程和低氧适应反应通路。具体来说，我们将检查MYB/HIF-1α 串扰改变了它们的基因组占有率，导致转录组的变化，并表现出低氧的特征 由它们共同或独立调节的适应性反应表型。在目标3中，我们将研究 MYB和HIF-1α在胰腺癌进展和转移中的协同作用 使用基因工程的荧光素酶标记的myb和hIF-1α表达或敲除PC细胞 小鼠原位移植模型。将进行组织学和免疫组织化学研究以衡量变化 在肿瘤缺氧、血管形成、细胞增殖/凋亡和转移中起重要作用。最后，在目标4中，我们将研究 免疫组织化学方法检测PC中MYB-HIF-1α串扰的临床意义 胰腺肿瘤样本以及邻近和健康的正常胰腺组织以评估发病率， MYB和HIF-1α的表达强度及共表达。我们还将检查它们的相关性(单独和在 联合)与肿瘤分级、分期和患者的生存有关。总而言之，这些研究将带来新的见解 PC中一种新的分子串扰(MYB/HIF-1α)的功能和机制意义 病理生物学，并突出其临床意义。由此产生的数据将增强我们对 PC的分子发病机制，从而促进了其预防和治疗的新方法的发展 治疗。因此，拟议的研究具有重大的潜力，可以影响胰腺癌的研究 最终将支持对这一毁灭性恶性肿瘤的有效管理的各个层面。

Tumor cells inevitably face hypoxia during the course of their progression and their adaptation to hypoxic stress promotes invasive, metastatic and treatment-resistant phenotypes. Therefore, understanding the molecular basis underlying adaptive responses to hypoxia and identification of involved molecular targets will greatly facilitate the development of effective strategies for cancer management. We have recently provided first experimental evidence for a pathobiological role of MYB in pancreatic cancer (PC). Our novel preliminary findings now demonstrate i) role of MYB in hypoxic cell survival, ii), MYB-mediated regulation of HIF-1α, and iii) MYB-HIF-1α interaction and co-localization. In other novel findings, we show differential binding of MYB to its two target gene promoters under hypoxia. In addition, our novel data support the clinical significance of MYB by showing its wide-spread expression in pancreatic tumor cases, which is also suggestive of its association with increasing tumor-grade and patient's survival. Based on these compelling findings, we hypothesize that MYB-HIF1α crosstalk plays an important role in pancreatic cancer progression and metastasis, which will be tested in four specific aims. In aim 1, we will investigate the regulatory cross-talk between MYB and HIF-1α by studying coordinated regulation of MYB and HIF-1α under hypoxia, and any reciprocity that may exist between them. In aim 2, we will define the role of interaction between MYB and HIF-1α in their transcriptional reprogramming and hypoxia adaptive-response pathways. Specifically, we will examine if the MYB/HIF-1α crosstalk alters their genomic occupancy leading to changes in transcriptome, and characterize hypoxia adaptive-response phenotypes that are jointly or independently regulated by them. In aim 3, we will examine the cooperative functional significance of MYB and HIF-1α in pancreatic tumor progression and metastasis by using genetically-engineered, luciferase-tagged MYB- and HIF-1α expressing or knockout PC cells in an orthotopic mouse model. Histological and immunohistochemical studies will be performed to measure changes in tumor hypoxia, vasculature, cell proliferation/apoptosis, and metastasis. Finally, in aim 4, we will study the clinical significance of MYB-HIF-1α cross-talk in PC by performing immunohistochemical analysis in human pancreatic tumor samples along with adjacent and healthy normal pancreatic tissues to assess incidence, intensity and co-expression of MYB and HIF-1α. We will also examine their correlation (alone and in combination) with tumor -grade, -stage, and patient's survival. Together, these studies will deliver novel insight into the functional and mechanistic significance of a novel molecular cross-talk (MYB/HIF-1α) in PC pathobiology, and highlight its clinical significance. Resulting data would enhance our understanding of molecular pathogenesis of PC and, thus, facilitate the development of novel approaches for its prevention and treatment. Therefore, proposed studies have significant potential to impact pancreatic cancer research at various levels that will ultimately support effective management of this devastating malignancy.