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

描述（由申请人提供）：目前尚无可靠的体外脑肿瘤模型可预测人体药物反应。临床和研究证据表明，肿瘤中的一小部分癌症干细胞（CSC）主要负责肿瘤的发生、进展、复发和对治疗药物的耐药性。这些细胞具有自我更新能力和无限的增殖潜力.尽管靶向CSC代表了一种潜在的治疗方法，但从人细胞系或原发性癌症标本中分离CSC是非常具有挑战性的，因为它们在整个肿瘤细胞群中所占的比例很小。现有的用于分离和扩增CSC的方法是无效的、繁琐的、昂贵的和不可靠的。在这里，我们的目标是开发临床相关的和预测性的体外人肿瘤模型，用于快速和低成本的抗CSC治疗药物评估。拟议的研究使用由壳聚糖和藻酸盐（CA）的复杂支架制成的先进3D系统，这两种天然存在的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支架将作为选择性更新和快速富集CSC的利基。一旦初步系统建立了最佳的结构和机械性能，证明CSC更新，我们计划进一步改善和微调我们的肿瘤模型，通过引入环境因素，如生化涂层，缺氧，和人类基质信号传导因子到CA支架人类胶质母细胞瘤培养。预期所建立的最佳CA支架模型支持从细胞系、原代GBM细胞和新鲜切除的GBM组织形成CSC富集的肿瘤球状体。来自植入裸鼠中的球状体的少量细胞预期形成原位肿瘤并重现GBM表型。由于GBM的死亡率和预后差以及我们在GBM治疗方面的广泛临床和研究经验，选择GBM作为所提出研究的靶肿瘤。本研究的具体目标是：1）确定CA支架的微观结构和力学性能对CSC富集的作用，建立CSC富集的肿瘤球体模型; 2）研究CA支架的微环境因素在CSC富集中的作用，以及CSC富集的肿瘤球体的致瘤能力;和3）在药物测试中使用肿瘤模型用于个性化癌症治疗和设计特异性靶向CSC用于GBM治疗的治疗策略。本研究将为有效评价潜在的治疗药物提供一个新的平台 通过提供更准确和稳定的肿瘤微环境，从而大大缩短了药物开发的时间并降低了药物开发的成本。开发的肿瘤模型还将使研究人员和医疗从业者能够研究调节CSC自我更新和分化的分子机制，并深入了解肿瘤形成和耐药性的起源。

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.