(PQC4) Fate of cells disseminating from human breast cancer xenografts

描述（由申请人提供）：转移性疾病是癌症死亡的主要原因。然而，正如不是所有的原发性癌症都容易转移一样，并非所有在继发部位发现的肿瘤细胞都是危及生命的。原发肿瘤部位的播散可发生在肿瘤发展的相对早期，继发部位的细胞可能具有从惰性到侵袭性恶性肿瘤的性质。该提案旨在解决“我们如何确定从另一个部位的原发肿瘤中发现细胞的重要性，以及可以开发哪些方法使这种诊断在临床上有用？”这一具有挑衅性的问题，成功回答这个问题将有望确定肿瘤的新致命弱点，这可能是开发新疗法的基础。提出这项研究的基本原理是基于我们的初步研究表明，人类乳腺癌异种移植物在全身传播细胞，这些细胞具有与母体肿瘤不同的独特特征。鉴于我们的新见解，我们现在建议分析来自人类乳腺癌异种移植模型的原发肿瘤和播散细胞，以寻找播散和转移的生物标志物；利用微流控单细胞PCR分析单细胞基因表达特征，确定这些群体中细胞的异质性；确定播散的肿瘤细胞在移植后是否具有启动肿瘤的能力；分析播散性肿瘤细胞生长或不活跃的微环境特征；并验证是否有扩散和转移。这些研究将开启对特定表型单细胞移植的进一步研究，以了解哪些变化对转移至关重要。了解恶性癌细胞与其周围非恶性间质之间复杂相互作用的分子机制是癌症研究的主要挑战之一，一旦了解了这一点，将有助于更好地了解哪些播散性肿瘤细胞是静止的，哪些可能会导致积极转移。这种理解将形成新的生物标志物和药理学干预的基础。

DESCRIPTION (provided by applicant): Metastatic disease is the major cause of death from cancer. However, just as not all primary cancers are prone to metastasize, not all tumor cells found at secondary sites are life-threatening. Dissemination from a primary tumor site can occur relatively early in tumor development, and cells at secondary sites may have properties that range from indolence to aggressive malignancy. This proposal is designed to address the provocative question "How do we determine the significance of finding cells from a primary tumor at another site and what methods can be developed to make this diagnosis clinically useful?" successfully answering this question would be expected to identify new Achilles' heels for tumors which could be the basis for developing novel therapeutics. The rationale for the proposed research is based on our preliminary studies showing that human breast cancer xenografts disseminate cells around the body and that these cells have distinct profiles that differ from the parent tumor. Given our novel insights, we now propose to analyze primary tumors and disseminated cells from human xenograft models of breast cancer for biomarkers of dissemination and metastasis; determine the heterogeneity of the cells in these populations by characterizing gene expression in single cells using micro-fluidic single cell PCR analysis; determine whether the disseminated tumor cells have the ability to initiate tumors upon transplantation; analyze the characteristics of the microenvironment of the disseminated tumor cells in which they flourish or remain indolent; and validate the hits for dissemination and metastasis. These studies will open up further studies with transplant of single cells of specific phenotypes, to learn which changes are crucial for metastasis. Understanding the molecular mechanisms of this complex interplay between malignant cancer cells and their surrounding non-malignant stroma represents one of the major challenges in cancer research, which once understood, will foster a better understanding of which disseminated tumor cells are quiescent and which are likely to give rise to metastases aggressively. This understanding will form the basis for new biomarkers and pharmacological interventions.