New 3D tumor models to rapidly test drugs for brain cancer therapy

描述(由申请人提供)：目前还没有可靠的脑瘤体外模型来预测人类的药物反应。临床和研究证据表明，肿瘤中的一小部分肿瘤干细胞(CSCs)是肿瘤发生、发展、复发和耐药的主要原因。这些细胞具有自我更新能力和无限的增殖潜力。尽管靶向CSCs是一种潜在的治疗方法，但从人类细胞系或原发肿瘤标本中分离CSCs是非常具有挑战性的，因为它们只占整个肿瘤细胞群的很小比例。现有的分离和扩增CSC的方法是无效的、繁琐的、昂贵的和不可靠的。在这里，我们的目标是开发具有临床相关性和预测性的体外人类肿瘤模型，用于快速、低成本地评估抗肿瘤干细胞治疗的药物。这项拟议的研究使用了一种先进的3D系统，该系统由壳聚糖和海藻酸盐(CA)组成的复合支架组成，这两种天然聚合物具有糖胺聚糖的代理结构，糖胺聚糖是天然细胞外基质(ECM)的主要成分。这些CA支架将成为选择性更新和快速丰富CSCs的利基。一旦初步建立了具有最佳结构和机械性能的CSC更新系统，我们计划通过将环境因素如生化涂层、低氧和人类基质信号因子引入CA支架来进一步改进和微调我们的肿瘤模型，用于人胶质母细胞瘤的培养。所建立的最佳CA支架模型有望支持从细胞系、原代GBM细胞和新鲜切除的GBM组织中形成富含CSC的肿瘤球体。来自球体的一小部分细胞被植入裸鼠体内，有望形成原位肿瘤并重现GBM表型。由于GBM的致命性和预后差，以及我们在GBM治疗方面的丰富临床和研究经验，我们选择GBM作为拟议研究的目标肿瘤。这项研究的具体目的是：1)确定CA支架的微观结构和力学性能对CSC的富集性的作用，并建立CSC富集型肿瘤球体模型；2)研究CA支架的微环境线索在CSC富集型肿瘤球体中的作用，以及CSC富集型肿瘤球体的致瘤能力；以及3)将肿瘤模型用于个体化癌症治疗的药物试验，并设计针对GBM治疗的CSCs的治疗策略。这项研究将为有效评估潜在的治疗方法提供一个新的平台 通过提供更准确和稳定的肿瘤微环境来开发药物，从而大大缩短药物开发的时间和降低成本。所开发的肿瘤模型还将使研究人员和医学从业者能够研究调节CSCs自我更新和分化的分子机制，并为了解肿瘤形成的来源和对治疗的耐药性提供洞察。

DESCRIPTION (provided by applicant): There are currently no reliable in vitro models for brain tumors that predict drug response in humans. Clinical and research evidence indicates that a small population of cancer stem cells (CSCs) in tumors are primarily responsible for tumor initiation, progression, recurrence, and resistance to therapeutics. These cells have self- renewal capacity and unlimited proliferative potential. Although the targeting of CSCs represents a potential treatment approach, it is very challenging to isolate CSCs from human cell lines or primary cancer specimens since they represent such a small proportion of the entire tumor cell population. Existing methods for isolation and expansion of CSCs are ineffective, cumbersome, expensive, and unreliable. Here we aim to develop clinically relevant and predicative in vitro human tumor models for rapid and low-cost drug assessment for anti- CSC therapy. The proposed research uses an advanced 3D system made of complex scaffold of chitosan and alginate (CA), two naturally occurring polymers that bear proxy structure of glycosaminoglycans, a major component of native extracellular matrix (ECM). These CA scaffolds will serve as a niche to selectively renew and rapidly enrich CSCs. Once the preliminary system is established with optimal structural and mechanical properties that demonstrate CSC renewal, we plan to further improve and fine-tune our tumor model by introducing environmental factors such as biochemical coatings, hypoxia, and human stromal signaling factors into CA scaffolds for human glioblastoma culture. The established optimal CA scaffold model is expected to support the formation of CSC-enriched tumor spheroids from cell lines, primary GBM cells, and freshly resected GBM tissue. A small number of cells from the spheroids implanted in nude mice are expected to form orthotopic tumors and recapitulate GBM phenotypes. GBM is selected as the target tumor for the proposed study due to its fatality and dismal prognosis and our extensive clinical and research experience of GBM treatments. Specific aims of the proposed research are to: 1) determine the role of microstructure and mechanical properties of CA scaffolds on enrichment of CSCs and establish CSC-enriched tumor spheroid models; 2) investigate the role of microenvironmental cues of CA scaffolds in CSC enrichment, and tumorigenic capacities of CSC-enriched tumor spheroids; and 3) use the tumor models in drug tests for personalized cancer treatment and design of therapeutic strategies that specifically target CSCs for GBM therapy. This research will provide a new platform for effectively evaluating potential therapeutic drugs by providing a more accurate and stable tumor microenvironment, thus considerably shortening the time and reducing the cost of drug development. The developed tumor models will also allow researchers and medical practitioners to study molecular mechanisms that regulate self-renewal and differentiation of CSCs, and provide insight into the origin of tumor formation and resistance to treatments.