N-cadherin in Extraskeletal Osteolineage Cells Modulates Tumor Growth

摘要 宿主微环境是肿瘤生长和转移所必需的，也是肿瘤生长和转移的主要决定因素。 抵抗治疗和复发。钙依赖性细胞黏附分子N-钙粘附素(Ncad)的表达 分子方面，肿瘤相关成纤维细胞(CAF)被报道有利于肿瘤的生长。NCAD是主要的 钙粘附素在骨细胞中表达，在细胞间黏附中发挥作用，但也调节信号和 差异化。在初步研究中，我们发现，与预期相反，Ncad基因(Cdh2)的消融 在表达成骨标志物Osterix(OSX+)的骨线细胞中，OSX+不影响骨移植 乳腺癌细胞；然而，皮下肿瘤生长得更快，肺转移发生得更早 野生型产仔。我们还发现，出乎意料的是，Ncad存在于以前未被识别的OSX+细胞中 在骨外肿瘤中。这些细胞具有更类似于成骨细胞而不是CAF的转录图谱， 有利于肿瘤的生长。此外，OSX+细胞中的Ncad下调p38反应基因，这是一种促进 肿瘤发生途径。在人类乳腺癌中，OSX+是预后不良的指标。这些初步结果 证明OSX+细胞中的Ncad是癌症进展的负调控因子，其作用与Ncad相反 报道了在CAF的行动。我们认为Ncad在肿瘤的发生中发挥了多种甚至相反的作用。 这取决于表达它的细胞环境，通过调节特定的信号通路。 基于这些初步数据，我们的中心假设是在促肿瘤的OSX+细胞中存在Ncad 通过调节调节肿瘤微环境的信号来抑制肿瘤生长。为了测试这一点 假设，我们提出了以下具体目标：特定目标1-骨外肿瘤的调节 Ncad在OSX+细胞中的生长；测试OSX+细胞中Ncad抑制肿瘤生长的假设；丢失 TAOC中的Ncad增加了小鼠肿瘤的生长和转移。OSX+Ncad+细胞与肿瘤的相关性 人类乳腺癌的分级。特异靶2-Ncad对促肿瘤信号的调控机制 在肿瘤相关的OSX+细胞中；检验OSX+细胞中的Ncad是p38上游调节因子的假设 OSX+细胞中Ncad的缺失导致p38依赖的PRO-2表达增强 致癌因子和Pten依赖信号减少，导致肿瘤微环境改变 并增强了肿瘤的发生。我们将使用体内方法，包括白喉毒素诱导的选择性细胞 消融、异种共生、谱系追踪以及无偏见转录方法(单细胞RNAseq) 解开骨外OSX+细胞中Ncad影响肿瘤生长的细胞和分子机制 和转移。我们还将确定Ncad在OSX+细胞中表达的临床病理相关性。 人类肿瘤。建议的研究结果将为开发新的标记奠定基础 旨在中断癌症环境支持的肿瘤进展和/或新的治疗策略 通过靶向肿瘤间质中的特定细胞进行生长和转移。

Abstract The host microenvironment is necessary for tumor growth and metastasis, and a major determinant of resistance to treatment and relapse. Expression of N-cadherin (Ncad), a calcium-dependent cell-cell adhesion molecule, in cancer associated fibroblasts (CAF) has been reported to favor tumor growth. Ncad is the main cadherin expressed in bone cells, where it functions in cell-cell adhesion, but also regulates signaling and differentiation. In preliminary studies we found that, contrary to expectations, ablation of the Ncad gene (Cdh2) in osteolineage cells – expressing the osteogenic marker, Osterix (Osx+) – does not affect bone engraftment of breast cancer cells; however, subcutaneous tumors grow faster and lung metastases develop earlier than in wild type littermates. We also find, unexpectedly, that Ncad is present in previously unrecognized Osx+ cells in extra-skeletal tumors. These cells have a transcriptomic profile more similar to osteogenic cells than to CAF, and favor tumor growth. Furthermore, Ncad in Osx+ cells down-regulates p38 responsive genes, a pro- tumorigenic pathway. In human breast cancer, Osx+ are an index of poor prognosis. These preliminary results demonstrate that Ncad in Osx+ cells is a negative regulator of cancer progression, an effect opposite to Ncad reported action in CAF. We contend that Ncad exerts multiple and even opposite actions on tumorigenesis depending on the cell context where it is expressed, via modulation of specific signaling pathways. Based on these preliminary data, our central hypothesis is that Ncad in pro-tumorigenic Osx+ cells restrains tumor growth by regulating signals that reprogram the tumor microenvironment. To test this hypothesis, we propose the following Specific Aims: Specific Aim 1 – Modulation of extra-skeletal tumor growth by Ncad in Osx+ cells; testing the hypothesis that Ncad in Osx+ cells restrains tumor growth; loss of Ncad in TAOC increases tumor growth and metastases in mice. Osx+ Ncad+ cells correlate with tumor grading in human breast cancer. Specific Aim 2 – Mechanisms of Ncad modulation of pro-tumorigenic signals in tumor-associate Osx+ cells; testing the hypothesis that Ncad in Osx+ cells is an upstream regulator of p38 and Pten signaling; loss of Ncad in Osx+ cells results in accentuated expression of p38-dependent pro- tumorigenic factors and decreased Pten dependent signals, leading to tumor microenvironment modification and enhanced tumorigenesis. We will use in vivo approaches, including diphtheria toxin-induced selective cell ablation, parabiosis, lineage tracking, as well as non-biased transcriptomic approaches (single cell RNAseq) to unlock the cellular and molecular mechanisms by which Ncad in extraskeletal Osx+ cells affects tumor growth and metastasis. We will also determine the clinical pathology correlates of Ncad expression in Osx+ cells in human tumors. Results of the proposed studies will lay the foundations for the development of new markers of tumor progression and/or new therapeutic strategies aimed at interrupting environmental support of cancer growth and metastasis by targeting specific cells in the tumor stroma.