Mechanisms of chemotherapy response and tumor re-initiation in lung cancer

描述（由申请人提供）：用标准化疗治疗实体瘤通常仅导致部分缓解。因此，由肿瘤再起始细胞（TRIC）驱动的化疗后肿瘤复发是癌症治疗中的中心问题。尽管其重要性，但对体内可变治疗反应和肿瘤再启动的机制知之甚少。理解人类中这种现象的一个重要问题是无法获得来自同一患者的化疗前后的匹配临床样本。与人类疾病非常相似的小鼠癌症模型是研究化疗后肿瘤再发生过程的有用工具。然而，很少有研究系统地利用这些模型来了解化疗反应。使用人类肺癌的小鼠模型，我们已经确定了一个肿瘤细胞的子集，可以通过其细胞表面标记物分离，并具有增加的内在耐药性化疗。我们利用与条件性转基因报告基因（tdRFP）杂交的Kras驱动的肺肿瘤模型，以促进通过FACs分离肿瘤细胞。这些小鼠的顺铂治疗导致CD 44 +;tdRFP+细胞的数量急剧减少，表明CD 44-细胞具有化疗抗性。使用检测顺铂-DNA加合物的抗体，我们发现CD 44-和CD 44+肿瘤细胞具有不同的DNA修复能力。该模型中的化学抗性与体外球体形成能力的显著增加相关。体外球体形成能力在CD 44-/CD 24+亚群中进一步富集。因此，我们已经发现了化疗耐药性和与癌症干细胞相关的特征（细胞表面标志物异质性，球体形成）之间的关系。本研究将利用小鼠遗传学、功能基因组学和原发性人肺癌样本，阐明非小细胞肺癌中化疗耐药的机制及其与肿瘤干细胞表型的关系。 公共卫生相关性：肿瘤如何对化疗产生反应以及为什么它们会产生耐药性还不完全清楚。我们将使用小鼠肺癌模型和原发性人类癌症样本来研究化疗耐药的机制。我们主要专注于了解肿瘤细胞如何修复化疗引起的损伤，以及它们如何能够修复这种损伤并存活。

DESCRIPTION (provided by applicant): Treatment of solid tumors with standard chemotherapy often leads only to partial response. Thus, tumor recurrence after chemotherapy driven by tumor-reinitiating cells (TRICs) is a central problem in cancer therapy. Despite its importance, the mechanisms accounting for variable therapy response and tumor re-initiation in vivo are poorly understood. A significant problem in understanding this phenomenon in humans is the inaccessibility of matched clinical samples before and after chemotherapy from the same patient. Mouse models of cancer that closely mimic the human disease are useful tools to study the process of tumor re- initiation after chemotherapy. However, few studies have systematically utilized these models to understand chemotherapy response. Using a mouse model of human lung cancer, we have identified a subset of tumor cells that can be isolated by their cell surface markers and have an increased intrinsic resistance to chemotherapy. We utilized a Kras-driven lung tumor model crossed to a conditional transgenic reporter (tdRFP) in order to facilitate isolation of tumor cells by FACs. Cisplatin treatment of these mice leads to a dramatic decrease in the number of CD44+;tdRFP+ cells, suggesting that CD44- cells are chemotherapy resistant. Using an antibody that detects cisplatin-DNA adducts, we find that CD44- and CD44+ tumor cells have distinct DNA repair capacities. Chemoresistance in this model is associated with a dramatic increase in sphere-forming ability in vitro. In vitro sphere-forming ability is further enriched in a CD44-/CD24+ subpopulation. Thus, we have uncovered a relationship between chemoresistance and characteristics associated with cancer stem cells (cell surface marker heterogeneity, sphere formation). In this proposal, we will utilize mouse genetics, functional genomics and primary human lung cancer samples to elucidate the mechanism of chemoresistance and its relationship to the cancer stem cell phenotype in non-small cell lung cancer. PUBLIC HEALTH RELEVANCE: How tumors respond to chemotherapy and why they become resistant is not completely understood. We will use a mouse model of lung cancer and primary human cancer samples to study the mechanisms of chemotherapy resistance. We focus primarily on understanding how tumor cells repair injury causes by chemotherapy and how they are able to repair this injury and survive.