In vivo murine models of metastasis for therapeutic testing

描述（由申请人提供）：转移是人类癌症最致命的特征，但控制转移扩散的分子过程尚不清楚。癌症研究这一关键领域的主要障碍之一是缺乏可靠的基因新生癌症模型，导致区域和远处转移。基于癌细胞系的异种移植模型不能完全概括基质细胞和癌细胞在复杂微环境中的复杂相互作用。此外，使用免疫受损小鼠进行异种移植物移植的必要性排除了阐明原发性癌症与癌症进展中免疫系统之间可能的关键相互作用。Sharpless和Wong实验室最近创建了由活化的致癌Kras和并发肿瘤抑制因子Lkb1缺失驱动的小鼠肺癌和黑色素瘤模型，该模型具有约60%的区域和远处转移外显率。我们证明了Lkb1功能的丧失在促进癌症侵袭和转移中是至关重要的，并解剖了在这一过程中至关重要的信号通路。我们现在通过将p53突变等位基因整合到Lkb1/Kras突变小鼠中进一步改进了这种遗传模型。同时Lkb1和p53丢失的Kras驱动的肺癌或黑色素瘤的复合突变小鼠具有远处血行转移（100%外显率），因此显示出Lkb1和p53不同且独立的肿瘤抑制功能。远处器官包括淋巴结、脾脏、肾脏、肝脏、骨骼和大脑，概括了在人类肺癌和黑色素瘤中观察到的全部转移部位。在此建议下，我们希望进一步表征和完善这些转移性癌症模型，并将体内非侵入性成像标记（荧光素酶和增强的绿色荧光蛋白）纳入这些复合突变小鼠中，以便使用最新的体内非侵入性成像技术无创地跟踪微转移的位置。然后，这些模型将用于测试能够杀死这些癌症并抑制转移性扩散的靶向治疗方法。与UNC综合化学生物学和药物发现中心的合作者一起，我们还将开发通过抑制Lkb1活性来增强转移行为的小分子工具化合物。这些研究将对这些癌症对各种治疗的原发和获得性耐药性产生重要见解，以帮助制定更好的治疗策略。

DESCRIPTION (provided by applicant): Metastasis is the most lethal feature of human cancers, but the molecular processes that govern metastatic spread are not well understood. One of the major obstacles in this crucial area of cancer research is the lack of faithful genetic de novo cancer model that results in regional and distant metastases. Xenograft models based on cancer cell lines cannot fully recapitulate the intricate interplay in the complex microenvironment of stromal and cancer cells. In addition, the necessity of using immuno-compromised mice for xenograft transplants precludes elucidation of the likely critical interaction between the primary cancer and the immune system in cancer progression. The Sharpless and Wong laboratories have recently generated de novo mouse lung cancer and melanoma models driven by activated oncogenic Kras and concurrent tumor suppressor Lkb1 loss that has a >60% penetrance of regional and distant metastases. We demonstrated that loss of Lkb1 function is crucial in the promotion of cancer invasion and metastasis and dissected the signaling pathways that are crucial to this process. We have now further improved this genetic model by incorporating a p53 mutant allele into the Lkb1/Kras mutant mice. Compound mutant mice with Kras driven lung cancer or melanoma that have concurrent Lkb1 and p53 loss have distant hematogenous metastases (100% penetrance), thus demonstrating distinct and separate tumor suppressor functions for Lkb1 and p53. Distant organs harboring metastases include lymph nodes, spleen, kidney, liver, bone and brain, recapitulating the full spectrum of metastatic sites observed in association with human lung cancers and melanoma. With this proposal, we wish to further characterize and refine these metastatic cancer models and incorporate in vivo non-invasive imaging markers (luciferase and enhanced green fluorescent protein) into these compound mutant mice to permit tracking of the location of micro- metastasis non-invasively using the latest in vivo non-invasive imaging techniques. These models will then be used to test targeted therapeutics that can kill these cancers and inhibit metastatic spread. With collaborators in the UNC Center for Integrative Chemical Biology and Drug Discovery, we will also develop small molecule tool compounds that will enhance metastatic behavior by inhibiting Lkb1 activity. These studies will yield important insights into primary and acquired resistance of these cancers to the various treatments to help facilitate better treatment strategies.