Molecular Diagnostics for Malignant Effusion

描述(申请人提供)：癌症死亡率和发病率主要与复发的耐药疾病有关，在这些疾病中，分子机制尚不清楚。本研究的目的是：1)确定一种新的肿瘤复发相关基因NAC-1(BTB/POZ基因家族的成员)在药物复发发生中的生物学作用；2)评估NAC-1在促进细胞存活和化疗耐药中的分子途径。目前的项目是基于我们先前的提案(CA103937)，该提案旨在识别癌症中潜在的诊断和治疗分子。在我们先前研究中发现的几个新的肿瘤相关标记物中，我们重点关注NAC-1，因为该基因在复发的化疗耐药的卵巢癌中优先表达，并且其在原发肿瘤中的高表达与肿瘤的早期复发相关。以前的研究已经强调了btb/POZ基因如bcl6在人类癌症中的新角色。在我们的初步研究中，我们证明了NAC-1分子通过BTB/POZ结构域进行同源二聚。在小鼠异种移植模型中，仅含有BTB/POZ结构域的NAC-1突变体的诱导表达破坏了NAC-1的二聚化，防止了肿瘤的形成，并促进了肿瘤细胞的凋亡。另一方面，NAC-1的过表达促进了小鼠卵巢表面上皮细胞和NIH3T3细胞的肿瘤生长。基于这些发现，我们假设NAC-1分子通过NAC-1同源二聚化促进肿瘤生长和化疗耐药，从而促进肿瘤复发。NAC-1的致癌表型由其下游基因介导，包括参与GADD45途径的Gadd45GIP1。为了验证这一假设，我们提出了以下目标。目的1：确定NAC-1基因上调是否参与耐药的发生。目的2：鉴定NAC-1控制的下游靶基因，这些靶基因对肿瘤细胞的耐药性和/或生存至关重要。目的3：探讨Gadd45GIP1是否通过GADD45途径介导NAC-1的功能。本研究的结果有望阐明NAC-1在肿瘤进展中的作用，并将为NAC-1靶向治疗复发癌症的未来发展提供分子基础。

DESCRIPTION (provided by applicant): Cancer mortality and morbidity are mainly related to recurrent chemoresistant diseases in which the molecular mechanisms are poorly understood. The objective of this study is to i) determine the biological roles of a new cancer recurrence-associated gene called NAC-1 (a member of the BTB/POZ gene family), in the development of drug recurrence and to ii) assess the molecular pathways of NAC-1 in contributing to cell survival and chemoresistance. The current project is based on our previous proposal (CA103937) which aimed to identify the potential diagnostic and therapeutic molecules in cancer. Among several novel cancer-associated markers we identified in the previous study, we focus on NAC-1 because the gene is preferentially expressed in recurrent chemoresistant ovarian cancer and its high level of expression in primary tumors is associated with early tumor recurrence. Previous studies have highlighted the emerging roles of BTB/POZ genes such as BCL- 6 in human cancer. In our preliminary study, we demonstrate that NAC-1 molecules homo-dimerize through the BTB/POZ domain. Induced expression of the NAC-1 mutant containing only the BTB/POZ domain disrupts NAC-1 dimerization, prevents tumor formation and promotes tumor cell apoptosis in a mouse xenograft model. Over-expression of NAC-1, on the other hand, enhances tumor growth of ovarian surface epithelial cells and NIH3T3 cells in mice. Based on these findings, we hypothesize that NAC-1 molecules contribute to tumor recurrence by enhancing tumor growth and chemoresistance through NAC-1 homodimerization. The oncogenic phenotypes of NAC-1 are mediated by its downstream genes including Gadd45GIP1 that participates in the Gadd45 pathway. To test this hypothesis, we proposed the following aims. Aim 1: Determine whether NAC-1 upregulation contributes to the development of drug resistance. Aim 2: Characterize the NAC-1 controlled downstream target genes that are essential for drug resistance and/or survival in tumor cells. Aim 3: Assess if Gadd45GIP1 mediates the functions of NAC-1 through the Gadd45 pathway. It is expected that the results from this study will elucidate the roles of NAC-1 in tumor progression and will provide the molecular foundation for future development of NAC-1 targeted therapy in recurrent cancers.