Modeling Therapy of Disseminated Cancer Cells in Bone Marrow (PQ 17)

描述(由申请人提供)：根据癌症研究界和NCI的结论，现有药物测试方法的低效和不准确是阻碍新药开发和临床转化以显著改进癌症治疗的关键障碍(挑衅性问题17)。为了克服这些障碍，我们将开发一种新的骨髓微环境中播散性乳腺癌细胞的3D细胞培养模型。我们对骨髓微环境的关注受到以下因素的驱动：即使在看似局限于原发肿瘤的患者身上，也会出现高频率的播散性癌细胞；相对于原发肿瘤，针对转移癌的药物活性有限，以及90%的癌症死亡是由转移疾病引起的。我们的模型将包括多种类型的人骨髓基质细胞，包括间充质干细胞、内皮细胞和成骨细胞。这些细胞中的一种或多种形成保护性的利基环境，可能通过细胞间信号通路对转移性乳腺癌细胞产生耐药性。我们将优化培养条件，利用一种创新的成像技术来量化3D球体内的氧合，从而复制出通常存在于人类骨髓中的低氧。我们将测试标准化疗药物在乳腺癌中的活性，以及整合到3D骨髓球体中的有希望的分子靶向化合物对代表乳腺癌固有分子亚型的人类细胞系的活性。我们还将测试化合物对仅作为小鼠异种移植传代的原代人类乳腺癌细胞的作用，并将3D培养中的反应与患者结果相关联。对于细胞系和原发肿瘤标本，我们将使用先进的光学成像方法来测量药物靶向、潜在的耐药机制和乳腺癌细胞对治疗的异质性反应。我们将通过实现以下具体目标来回答挑衅性的第17个问题：1)开发先进的3D培养系统，以分析骨髓中播散性人类乳腺癌细胞的治疗；2)量化化合物对代表人类乳腺癌分子亚类的乳腺癌细胞系和肿瘤启动细胞的作用；3)测定化合物对原发患者肿瘤样本的活性。总而言之，这项研究将建立一种简便、廉价、可重复性的模型，以测试潜在的抗癌药物，并将化合物与极有可能对治疗有反应的患者亚群准确匹配。该战略将加快新的、更有效的抗癌药物的临床转化，同时降低药物开发成本。

DESCRIPTION (provided by applicant): As determined by the cancer research community and NCI, inefficiencies and inaccuracies of existing methods for drug testing are critical obstacles preventing development and clinical translation of new drugs to dramatically improve cancer therapy (Provocative Question 17). To overcome these obstacles, we will develop a new 3D cell culture model of disseminated breast cancer cells in the bone marrow microenvironment. Our focus on the bone marrow microenvironment is driven by the high frequency of disseminated cancer cells even in patients with seemingly localized primary tumors, limited activity of drugs against metastases relative to primary tumors, and > 90% of cancer mortality caused by metastatic disease. Our model will incorporate multiple types of human bone marrow stromal cells, including mesenchymal stem cells, endothelium, and osteoblasts. One or more of these cell types form protective niches that may confer drug resistance to metastatic breast cancer cells through intercellular signaling pathways. We will optimize culture conditions to reproduce hypoxia normally present in human bone marrow, using an innovative imaging technique to quantify oxygenation within 3D spheroids. We will test activity of standard chemotherapeutic drugs in breast cancer and promising molecularly-targeted compounds against human cell lines representative of intrinsic molecular subtypes of breast cancer integrated into 3D bone marrow spheroids. We also will test compounds against primary human breast cancer cells passaged only as mouse xenografts and correlate responses in 3D culture with patient outcomes. For both cell lines and primary tumor specimens, we will use advanced optical imaging methods to measure drug targeting, potential mechanisms of drug resistance, and heterogeneous responses of breast cancer cells to treatment. We will answer Provocative Question 17 by accomplishing the following specific aims: 1) develop an advanced 3D culture system to analyze treatment of disseminated human breast cancer cells in bone marrow; 2) quantify effects of compounds on breast cancer cell lines representative of molecular subclasses of human breast cancer and tumor-initiating cells; 3) determine activities of compounds against primary patient tumor samples. Collectively, this research will establish a facile, inexpensive, reproducible model to test potential cancer drugs and accurately match compounds with patient subpopulations highly likely to respond to treatment. The strategy will accelerate clinical translation of new, more effective cancer drugs while reducing costs of drug development.