Molecular Diagnostics for Malignant Effusion

描述（由申请人提供）：癌症死亡率和发病率主要与复发性化疗耐药疾病相关，其中分子机制知之甚少。本研究的目的是i）确定一种新的癌症复发相关基因NAC-1（BTB/POZ基因家族的成员）在药物复发发展中的生物学作用，以及ii）评估NAC-1在促进细胞存活和耐药性方面的分子途径。目前的项目是基于我们以前的提案（CA 103937），旨在确定潜在的诊断和治疗癌症的分子。在我们在先前的研究中确定的几种新的癌症相关标志物中，我们专注于NAC-1，因为该基因优先在复发性化疗耐药卵巢癌中表达，并且其在原发性肿瘤中的高水平表达与早期肿瘤复发相关。以前的研究已经强调了BTB/POZ基因如BCL- 6在人类癌症中的新作用。在我们的初步研究中，我们证明了NAC-1分子通过BTB/POZ结构域同源二聚化。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NAC-1二聚化，防止肿瘤形成并促进肿瘤细胞凋亡。另一方面，NAC-1的过表达增强了小鼠卵巢表面上皮细胞和NIH 3 T3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同源二聚化增强肿瘤生长和化疗耐药性而促进肿瘤复发。NAC-1的致癌表型由其下游基因介导，包括参与Gadd 45途径的Gadd 45 GIP 1。为了验证这一假设，我们提出了以下目标。目的1：确定NAC-1上调是否有助于耐药性的发展。目的2：鉴定NAC-1控制的肿瘤细胞耐药和/或存活所必需的下游靶基因。目的3：探讨Gadd 45 GIP 1是否通过Gadd 45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，并为将来开发NAC-1靶向治疗复发性癌症提供分子基础。

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.