Mechanisms of Breaking Indolence in Squamous Cell Carcinoma

 描述（由申请人提供）： 人类鳞状细胞癌（SCC）起源于皮肤和口腔，可以以惰性形式存在，类似于冬眠，没有明显的肿瘤扩张或局部/全身浸润。SCC的惰性限制了肿瘤在原发部位的净扩张和侵袭，这一点还没有得到充分的研究。很少有人知道为什么惰性SCC持续存在，以及它们何时演变成一种侵略性的形式。如果没有SCC惰性的分子和细胞标志物，它们要么被过度治疗从而导致发病，要么被治疗不足从而导致死亡增加。为了克服人类缺乏匹配的惰性和进化的SCC进行比较研究，我们创建了一个小鼠模型系统，其中从相同的原发性肿瘤发展的肿瘤可以进入和打破惰性。在该系统中，我们将KrasG 12 D突变体和Smad 4缺失（人类SCC中两种最常见的遗传改变）靶向角蛋白K15+干细胞。这些小鼠迅速发展SCC。在将这些SCC移植到免疫受损或免疫活性小鼠的皮肤后，一些生长类似于亲本肿瘤（非惰性），而另一些变得惰性。当惰性SCC脱离惰性时，它们迅速生长和转移。这种独特的模型系统提供了匹配的惰性和非惰性SCC进行纵向比较。根据我们的初步数据，我们假设：打破SCC惰性不是简单地离开增殖休眠或克服微环境压力。控制肿瘤细胞自我更新和运动的内在肿瘤上皮特性和微环境影响是打破SCC惰性的关键因素。基于我们的初步数据，目标1将评估肿瘤起始细胞（TIC）子集的数量和性质是否影响无痛性。目标2将评估EMT介导的TIC扩增和细胞迁移是否足以有助于打破惰性。目的3确定肿瘤相关巨噬细胞和B淋巴细胞对肿瘤惰性的净效应。在所有三个目标中，将在来自我们的肿瘤库的人SCC中检查负责打破小鼠SCC惰性的细胞过程和分子，以确定这些细胞和分子标志物是否与人SCC中的非惰性或非惰性行为相关，从而预测不良预后。我们独特的模型系统、高通量方法和跨物种比较将显著加速与打破SCC惰性相关的标志物的鉴定。候选标志物的拟议功能验证将同时测试治疗策略以阻止SCC逃避。

 DESCRIPTION (provided by applicant): Human squamous cell carcinomas (SCCs) arising from the skin and oral cavity can present in an indolent form, similar to hibernation, with no obvious tumor expansion or local/systemic invasion. SCC indolence, which restricts net tumor expansion and invasion at the primary site, is severely understudied. Very little is known about why indolent SCCs persist and when they evolve into an aggressive form. Without molecular and cellular markers of SCC indolence, they are either over-treated thus causing morbidity or under-treated thus resulting in increased death. To overcome the lack of matched indolent and evolved SCCs in humans for comparative studies, we created a mouse model system, in which tumors developed from the same primary tumor can enter into and break out of indolence. In this system, we targeted a KrasG12D mutant and Smad4 deletion, the two most frequent genetic alterations in human SCCs, into keratin K15+ stem cells. These mice rapidly develop SCCs. After transplanting these SCCs to the skin of immune compromised or immune competent mice, some grew similarly to parental tumors (non-indolent) while others became indolent. When indolent SCCs were out-of-indolence, they grew and metastasized rapidly. This unique model system provides matched indolent and out-of-indolence SCCs for longitudinal comparisons. Based on our preliminary data, we hypothesize: Breaking SCC indolence is not simply leaving proliferative dormancy or overcoming microenvironmental stress. Intrinsic tumor epithelial properties and microenvironmental influences that control self-renewal and motility of tumor cells are key contributors of breaking SCC indolence. Based on our preliminary data, Aim 1 will assess if the numbers and properties of a subset of tumor initiating cells (TICs) influence indolence. Aim 2 will assess if EMT-mediated TIC expansion and cell migration are sufficient to contribute to breaking indolence. Aim 3 will determine the net effect of tumor-associated macrophages and B lymphocytes on tumor indolence. In all three aims, cellular processes and molecules responsible for breaking SCC indolence in mice will be examined in human SCCs from our tumor bank to determine if these cellular and molecular markers correlate with non- or out-of-indolence behavior in human SCCs, thus predicting poor prognosis. Our unique model system, high throughput approaches and cross- species comparisons will significantly accelerate identification of markers associated with breaking SCC indolence. The proposed functional validation of candidate markers will simultaneously test therapeutic strategies to halt SCC evasion.