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

描述(申请人提供)：用标准化疗治疗实体瘤通常只有部分反应。因此，肿瘤再启动细胞(TRICs)驱动化疗后的肿瘤复发是肿瘤治疗中的一个中心问题。尽管它很重要，但体内不同的治疗反应和肿瘤重新启动的机制还知之甚少。在人类中理解这种现象的一个重要问题是无法从同一患者的化疗前后获得匹配的临床样本。模拟人类疾病的小鼠癌症模型是研究化疗后肿瘤复发过程的有用工具。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，我们已经确定了一组肿瘤细胞，这些细胞可以通过细胞表面标记分离出来，并且对化疗具有更强的内在抵抗力。我们利用Kras驱动的肺癌模型与条件转基因报告基因(TdRFP)杂交，以便于FACS分离肿瘤细胞。顺铂对这些小鼠的治疗导致CD44；tdRFP细胞数量急剧减少，表明CD44-细胞对化疗具有耐药性。使用检测顺铂-DNA加合物的抗体，我们发现CD44-和CD44肿瘤细胞具有不同的DNA修复能力。在这个模型中，化疗耐药性与体外球体形成能力的显著增加有关。体外球体形成能力在CD44-/CD24亚群中进一步丰富。因此，我们发现了化疗耐药性与癌症干细胞相关特性(细胞表面标记的异质性、球体形成)之间的关系。在这个方案中，我们将利用小鼠遗传学、功能基因组学和原代人类肺癌样本来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。 与公共卫生相关：肿瘤对化疗的反应以及为什么它们变得耐药还不完全清楚。我们将使用小鼠肺癌模型和原发人类癌症样本来研究化疗耐药的机制。我们主要关注了解肿瘤细胞如何修复化疗造成的损伤，以及它们如何能够修复这种损伤并存活下来。

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.