Regulatory Role of Mitochondrial DNA in Bladder Cancer Progression

摘要 膀胱癌（BCa）是一种常见的实体瘤，当局部晚期或晚期时， 转移性的即使采用积极的手术或药物治疗，也只能看到适度的改善。最 晚期癌症患者最终死于具有最显著预后因素的疾病 即存在转移。虽然已经做了很多工作来确定转移性肿瘤的存在， 淋巴结中的肿瘤细胞，目前很少有研究探索控制BCa进展为 转移表型现在公认原发肿瘤固有的遗传因素， 与原发肿瘤无关的微环境因素参与转移进展。一个关键 未充分研究的转移效率调节因子可能是线粒体DNA（mtDNA）。线粒体变异 线粒体DNA的拷贝数和丢失被认为是BCa的致病事件， 已经在患者样本中进行了测量;然而，对mtDNA的功能贡献知之甚少 由于缺乏合适和可用的实验室模型，转移进展。我们开发了一个模型 以确定mtDNA的贡献，命名为MNX -细胞核交换。转基因小鼠 由不同菌株的核DNA匹配但线粒体DNA不同产生， 在恒定的核背景下测定mtDNA含量。Welch实验室（mPI）先前的研究使用这些 在乳腺癌和黑色素瘤模型中的小鼠表明mtDNA是一种新的转移效率调节剂。此外，委员会认为， mtDNA在微环境中的变化独立于肿瘤本身，可能进一步调节肿瘤的潜在作用。 转移然而，没有这样的研究已经在基因认证的模型中完成， 概括了人类的疾病我们的初步数据表明，C3 H/HeN mtDNA转移到C57 B1/6 J中， 核背景导致更快的肿瘤进展，特别是在雌性小鼠中。我们假设 特异性改变线粒体遗传学将从根本上改变肿瘤进展和转移 通过肿瘤细胞和肿瘤间质中的信号传导变化来调节BCa的速率。我们将使用高度 在具有不同BCa的小鼠品系中建立了经证实的N-丁基-N-（4-羟丁基）亚硝胺（BBN）诱导的BCa模型 肿瘤形成率（C3 H/HeN和C57 BL/6 J）来研究这一假设。具体目标1： 使用WT和MNX小鼠评估mtDNA在原发性BCa肿瘤进展至转移中的作用。在特定 目的2，我们将确定WT和MNX中细胞和基质成分对BCa转移的贡献 小鼠这些研究将明确线粒体DNA在该模型中的作用，并导致未来的实验理解 线粒体DNA的丢失或获得如何特异性地影响小鼠实验室模型和患者。

ABSTRACT Bladder cancer (BCa) is a common solid tumor and exhibits poor outcomes when regionally advanced or metastatic. Only modest improvements are seen even with aggressive surgical or medical treatments. Most patients with advanced cancer ultimately succumb to their disease with the most significant prognostic factor being the presence of metastasis. While much work has been done on identifying the presence of metastatic tumor cells in lymph nodes, little research currently explores the mechanisms that govern BCa progression to a metastatic phenotype. It is now well recognized that genetic factors, intrinsic to the primary tumor, and microenvironmental factors, independent of the primary tumor are involved in metastatic progression. One key understudied regulator of metastatic efficiency may be mitochondrial DNA (mtDNA). Variations in mitochondrial copy number and loss of mtDNA have been implicated as pathogenic events in BCa, and changes in mtDNA have been measured in patient samples; however, little is understood about the functional contribution of mtDNA to metastatic progression due to lack of suitable and available laboratory models. We have developed a model to determine contributions of mtDNA, designated MNX – mitochondrial-nuclear exchange. Transgenic mice are generated with matched nuclear DNA but different mtDNA from separate strains such that maternal inheritance determines mtDNA content in constant nuclear backgrounds. Prior studies from the Welch lab (mPI) using these mice in breast and melanoma models indicate mtDNA is a novel metastasis efficiency regulator. Moreover, mtDNA changes in the microenvironment independent of the tumor itself may further regulate the potential for metastasis. However, no such studies have been done in genetically credentialed models that accurately recapitulate human disease. Our preliminary data indicates that transfer of C3H/HeN mtDNA into a C57Bl/6J nuclear background results in more rapid tumor progression, especially in female mice. We hypothesize that specifically altering mitochondrial genetics will fundamentally alter tumor progression and metastasis rates in BCa via signaling changes in both tumor cells and the tumor stroma. We will use the highly credentialed N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) induced BCa model in murine strains with different rates of tumor formation (C3H/HeN and C57BL/6J) to investigate this hypothesis. In Specific Aim 1, we will evaluate the role of mtDNA in primary BCa tumor progression to metastasis using WT and MNX mice. In Specific Aim 2, we will determine the contribution of cellular and stromal elements to BCa metastasis in WT and MNX mice. These studies will define the role of mtDNA in this model and lead to future experiments understanding how loss or gain of mtDNA specifically effects both murine laboratory models and patients.