Molecular Mechanisms in Gastrointestinal Stromal Tumor

摘要 胃肠道间质瘤（GIST）是最常见的人类肉瘤，通常起源于胃肠道肿瘤。 胃或小肠。癌症通常在KIT或PDGFRA中具有单一突变。Imatinib 和其他酪氨酸激酶抑制剂，攻击与这些突变基因相关的癌蛋白， 有效，但耐药性发展约18个月，治愈是罕见的。没有其他有效的 因此需要新的治疗方法。在过去的13年里，我们广泛地 在基因工程“敲入”小鼠模型中研究了对GIST的免疫反应， 新鲜的人类GIST手术标本。为了更深入地研究抗肿瘤免疫应答， 我们刚刚对来自肿瘤的50，000多个肿瘤内免疫细胞进行了单细胞RNA测序， 用载体或伊马替尼治疗的小鼠的平均存活时间。我们发现gdT细胞在肿瘤中富集， 与血液和脾脏相比。我们有初步的数据表明gdT细胞在体内抑制GIST的生长， 至少部分是由于IL-17分泌。此外，伊马替尼治疗增强了他们的IL-17产生。我们 还发现gdT细胞浸润人GIST，并产生IL-17，与小鼠模型相似。的 gdT细胞在人GIST或任何肉瘤中的重要性尚不清楚。我们有初步的 数据表明，gdT细胞的存在与GIST患者的总生存率呈正相关。我们 假设gdT细胞在对GIST的抗肿瘤免疫应答中起关键作用， 为了治疗效果而操作。在这个提议中，我们将研究gdT细胞在 通过首先定义gdT细胞抑制鼠GIST的机制，对小鼠和人GIST进行研究。接下来我们 将确定伊马替尼如何影响鼠GIST中的肿瘤内gdT细胞。有趣的是， 单细胞RNA表达的聚集揭示了我们小鼠肿瘤内gdT细胞的2个主要亚群 模型我们将研究它们的不同功能。我们将建立gdT细胞的翻译相关性， GIST。我们将在我们的小鼠模型中测试几种gdT细胞活化剂与伊马替尼的组合。 此外，我们将研究从新鲜的人GIST手术标本中分离的gdT细胞的功能 并将它们的存在与临床病理变量和免疫浸润相关联。最后，我们建议 对来自新鲜人GIST的肿瘤内免疫细胞进行scRNAseq。我们的单细胞RNA 测序数据给了我们一个前所未有的研究免疫反应的复杂性， GIST和已经形成了许多假设的基础上，在这个建议。当我们专注于GIST时， 我们期望我们的发现将与其他人类癌症中的gdT细胞相关。

ABSTRACT Gastrointestinal stromal tumor (GIST) is the most common human sarcoma and typically arises from the stomach or small intestine. The cancer generally has a single mutation, either in KIT or PDGFRA. Imatinib and other tyrosine kinase inhibitors that attack the oncoproteins associated with these mutated genes are effective, but resistance develops around 18 months and cure is rare. There are no other effective treatments so new therapeutic approaches are needed. Over the last 13 years, we have extensively studied the immune response to GIST in a genetically engineered “knockin” mouse model and over 300 fresh human GIST surgical specimens. To investigate the antitumor immune response in greater depth, we have just performed single-cell RNA sequencing on over 50,000 intratumoral immune cells from tumors of mice that were treated with vehicle or imatinib. We discovered that gdT cells are enriched in the tumor compared with blood and spleen. We have preliminary data that gdT cells suppress GIST growth in vivo, at least in part due to IL-17 secretion. Furthermore, imatinib therapy enhanced their IL-17 production. We also found that gdT cells infiltrate human GIST and they produce IL-17, similar to the mouse model. The importance of gdT cells in human GIST, or any sarcoma for that matter, is unknown. We have preliminary data that the presence of gdT cells correlates positively with overall survival in GIST patients. We hypothesize that gdT cells play a critical role in the antitumor immune response to GIST and can be manipulated for therapeutic efficacy. In this proposal, we will investigate the importance of gdT cells in mouse and human GIST by first defining the mechanism of gdT cell suppression of murine GIST. Next, we will determine how imatinib affects intratumoral gdT cells in murine GIST. Interestingly, unsupervised clustering of the single-cell RNA expression revealed 2 main subsets of intratumoral gdT cells in our mouse model. We will study their different function. We will establish the translational relevance of gdT cells in GIST. We will test several gdT cell activating agents in combination with imatinib in our mouse model. Furthermore, we will study the function of gdT cells isolated from fresh human GIST surgical specimens and correlate their presence to clinicopathologic variables and immune infiltrate. Lastly, we propose to perform scRNAseq on intratumoral immune cells from fresh human GISTs. Our single-cell RNA sequencing data have given us an unprecedented look into the complexity of the immune response to GIST and have formed the basis for numerous hypotheses in this proposal. While we are focused on GIST, we expect that our findings will have relevance to gdT cells in other human cancers.