The Role of the CXCR4/CXCL12 axis in endometriosis

描述（由申请人提供）：子宫内膜异位症与癌症一样，也被证明具有增殖、侵袭和血管生成增加的特征；然而，这种依赖雌激素的侵袭性疾病的具体机制尚不清楚。子宫内膜的两种主要细胞成分，即上皮细胞（EEC）和间质细胞（HESC），表现出CXCR4和CXCL12蛋白的差异表达：子宫内膜上皮细胞比间质细胞表达更高的CXCR4水平；相反，子宫内膜基质细胞表达更高水平的CXCL12，这是之前从其他人和我们实验室报道的。此外，我们发现在子宫内膜细胞系中，CXCR4的表达受雌二醇（E2）和孕酮（P4）的差异调节。最后，我们还发现CXCR4在大鼠子宫内膜异位症模型的病变以及人子宫内膜异位症组织中均显著过表达。CXCR4蛋白在子宫内膜异位症病变中的表达明显高于分泌控制的子宫内膜，其表达该趋化因子受体的表达最高。基于这些初步观察，我们假设CXCR4-CXCL12轴的激活是子宫内膜异位症发生和进展的关键步骤。具体而言，本研究旨在探讨CXCR4配体CXCL12诱导的CXCR4信号在子宫内膜异位症中促进细胞增殖、侵袭和血管生成的作用。提出这一建议的主要假设是，月经液中到达腹腔的子宫内膜异位症上皮细胞中CXCR4蛋白的过度表达，以及CXCL12的未知激活，刺激增殖、侵袭和血管生成，导致病变的建立。为了验证这些假设，首先将在子宫内膜和子宫内膜异位症细胞的背景下评估CXCR4-CXCL12轴在诱导增殖以及侵袭/迁移机制方面的功能（Specific Aim #1）。接下来，将确定这些细胞背景下CXCL12与CXCR4结合激活的分子机制（Specific Aim #2）。在Specific Aim #3中，CXCR4抑制剂CTCE-9908在预防子宫内膜异位症发展中的功效将通过一个经过充分验证的子宫内膜异位症大鼠模型进行体内评估。我们推测，子宫内膜异位症组织中的基质细胞以旁分泌方式产生CXCL12，从而创造了诱导表达cxcr4的上皮细胞存活的微环境。从这个项目中获得的知识对于理解子宫内膜细胞如何能够在异位部位增殖、侵袭和存活，以及炎症反应如何提供适当的细胞环境来诱导子宫内膜细胞在异位部位存活是很重要的。此外，这些研究将为针对CXCR4-CXCL12轴的这种不治之症的未来治疗方式的发展提供见解。

DESCRIPTION (provided by applicant): Endometriosis, like cancer, has also been shown to be characterized by increased proliferation, invasion and angiogenesis; however, the specific mechanisms underlying this estrogen-dependent, invasive disease are still unknown. The two main cellular components of the endometrium, namely epithelial (EEC) and stromal (HESC) cells, show a differential expression of CXCR4 and CXCL12 proteins: endometrial epithelial cells express higher CXCR4 levels than stromal cells; conversely, endometrial stromal cells expressed higher levels of CXCL12 as previously reported from others and our laboratory. Also, we showed that CXCR4 expression is differentially regulated by estradiol (E2) and progesterone (P4) in endometrial cell lines. Finally, we have also shown that CXCR4 is significantly overexpressed in the lesions of the rat model of endometriosis as well as in human endometriotic tissues. The expression of CXCR4 protein in the endometriotic lesions was significantly higher compared to secretory control endometrium, which expresses the highest expression of this chemokine receptor. Based on these preliminary observations, we hypothesize that activation of the CXCR4-CXCL12 axis is a key step in the development and progression of endometriosis. Specifically, this proposal aims to investigate the role of CXCR4 signaling induced by its ligand, CXCL12, in promoting cell proliferation, invasion, and angiogenesis in endometriosis. The main hypothesis driving this proposal is that overexpression of CXCR4 protein in endometriotic epithelial cells reaching the peritoneal cavity in the menstrual fluid, and its unchartered activation by CXCL12, stimulates proliferation, invasion, and angiogenesis leading to lesion establishment. To test these hypotheses, first the functionality of the CXCR4-CXCL12 axis in inducing proliferation as well as invasion/migration mechanisms will be assessed in the context of endometrial and endometriotic cells (Specific Aim #1). Next, the molecular mechanisms activated by CXCL12 binding to CXCR4 in these cellular contexts will be determined (Specific Aim #2). In Specific Aim #3, the efficacy of the CXCR4 inhibitor CTCE-9908 in preventing the development of endometriosis will be assessed in vivo using a well-validated rat model of endometriosis. We speculate that stromal cells in the endometriotic tissue produce CXCL12 in a paracrine manner, thus creating a microenvironment inducive to survival of CXCR4-expressing epithelial cells. The knowledge that will be gained from this project is important to understand how endometrial cells are able to proliferate, invade and survive in ectopic sites and how the inflammatory reaction can provide the appropriate cell environment to induce endometrial cell survival at ectopic locations. Also, these studies will provide insights fo the development of future therapeutic modalities for this incurable condition targeting the CXCR4-CXCL12 axis.