Han Weiguo, Jackson David A, Matissek Stephan J, Misurelli Jason A, Neil Matthew S, Sklavanitis Brandon, Amarsaikhan Nansalmaa, Elsawa Sherine F
Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115.
Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115
J Immunol. 2017 Jun 1;198(11):4481-4489. doi: 10.4049/jimmunol.1601490. Epub 2017 May 1.
The interaction between tumor cells and their surrounding microenvironment is essential for the growth and persistence of cancer cells. This interaction is mediated, in part, by cytokines. Although the role of cytokines in normal and malignant cell biology is well established, many of the molecular mechanisms regulating their expression remain elusive. In this article, we provide evidence of a novel pathway controlling the transcriptional activation of CD40L in bone marrow-derived stromal cells. Using a PCR-based screening of cytokines known to play a role in the biology of bone marrow malignancies, we identified CD40L as a novel GLI2 target gene in stromal cells. CD40L plays an important role in malignant B cell biology, and we found increased Erk phosphorylation and cell growth in malignant B cells cocultured with CD40L-expressing stromal cells. Further analysis indicated that GLI2 overexpression induced increased CD40L expression, and, conversely, GLI2 knockdown reduced CD40L expression. Using luciferase and chromatin immunoprecipitation assays, we demonstrate that GLI2 directly binds and regulates the activity of the CD40L promoter. We found that the CCR3-PI3K-AKT signaling modulates the GLI2-CD40L axis, and GLI2 is required for CCR3-PI3K-AKT-mediated regulation of the CD40L promoter. Finally, coculture of malignant B cells with cells stably expressing human CD40L results in increased Erk phosphorylation and increased malignant B cell growth, indicating that CD40L in the tumor microenvironment promotes malignant B cell activation. Therefore, our studies identify a novel molecular mechanism of regulation of CD40L by the transcription factor GLI2 in the tumor microenvironment downstream of CCR3 signaling.
肿瘤细胞与其周围微环境之间的相互作用对于癌细胞的生长和持续存在至关重要。这种相互作用部分由细胞因子介导。尽管细胞因子在正常和恶性细胞生物学中的作用已得到充分证实，但其表达调控的许多分子机制仍不清楚。在本文中，我们提供了一条控制骨髓来源的基质细胞中CD40L转录激活的新途径的证据。通过基于PCR的对已知在骨髓恶性肿瘤生物学中起作用的细胞因子进行筛选，我们确定CD40L是基质细胞中一种新的GLI2靶基因。CD40L在恶性B细胞生物学中起重要作用，并且我们发现与表达CD40L的基质细胞共培养的恶性B细胞中Erk磷酸化增加且细胞生长加快。进一步分析表明，GLI2过表达诱导CD40L表达增加，相反，GLI2敲低则降低CD40L表达。使用荧光素酶和染色质免疫沉淀分析，我们证明GLI2直接结合并调节CD40L启动子的活性。我们发现CCR3-PI3K-AKT信号传导调节GLI2-CD40L轴，并且GLI2是CCR3-PI3K-AKT介导的CD40L启动子调节所必需的。最后，恶性B细胞与稳定表达人CD40L的细胞共培养导致Erk磷酸化增加和恶性B细胞生长增加，表明肿瘤微环境中的CD40L促进恶性B细胞活化。因此，我们的研究确定了在CCR3信号下游的肿瘤微环境中转录因子GLI2对CD40L进行调控的一种新的分子机制。
