C/EBPβ in bone marrow stromal cell-mediated drug resistance of multiple myeloma

项目总结-C/EBPβ在骨髓基质细胞介导的多药耐药中的作用 骨髓瘤 表观遗传调控在许多生物过程中起着关键作用。我的首要目标是 实验室是为了了解血液系统癌症耐药的表观遗传机制 骨髓微环境。这项提案将调查一种转录调节因子的作用 亮氨酸拉链转录因子CCAAT/增强子结合蛋白β(C/EBpβ)在促进去甲肾上腺素中的作用 骨髓微环境下多发性骨髓瘤(MM)的新耐药性。MM是一种疾病 由恶性浆B细胞引起，主要分布在骨髓中。它是无法治愈的，很大程度上是因为 抗药性。造成耐药性的一个重要因素是BM的保护作用 微环境，包括促进生长的可溶性因子和与细胞的物理相互作用 基质细胞、成骨细胞和基质等成分。出现新的抗药性 在短时间内并且是可逆的，这表明表观遗传机制可能是一个重要的驱动因素。然而， 染色质调节剂在骨髓MM新发耐药中的作用机制 微环境在很大程度上仍未得到探索。我们的工作预测C/eBPβ是一个关键的转录调节因子 骨髓基质细胞激活信号通路的靶基因。骨髓基质细胞诱导了一个基因组- MM细胞基因表达(转录组)和染色质可及性(调节组)的广泛重编程， 主要受可溶性因素驱动。与编码基因组结合数据的综合分析表明C/eBPβ为 骨髓基质细胞诱导的转录组和调节组转化的主要贡献者。我们的预赛 结果确定C/EBPβ是一种很有前途的研究对象，可以用来理解De的出现的表观遗传学机制 MM中新的耐药性我们假设C/EBPβ调节染色质的可及性 转录调控，并通过其参与可溶性因子介导的耐药 Mm细胞。我们将从两个方向检验这一假设。在目标1中，我们将首先验证促进成长 C/EBPCRISPR-KOβ在骨肉瘤细胞系中的作用 免疫缺陷的NSG小鼠。然后我们将定义由C/EBPβ调控的可溶性因子诱导的特征基因 通过对全基因组基因表达谱和可及染色质的综合分析。在目标2中， 我们将研究C/EBPβ缺失对可溶性因子介导的IMIDS耐药性的影响，并定义 潜在的全基因组转录信号与抗性相关，并受C/eBPβ调控。结果来自 这一建议将确立靶向C/EBPβ途径是否是开发 抑制骨髓微环境促进的从头耐药性的新治疗策略 Mm细胞。

PROJECT SUMMARY – C/EBPβ in bone marrow stromal cell-mediated drug resistance of multiple myeloma Epigenetic regulation plays a critical role in numerous biological processes. The overarching goal of my laboratory is to understand epigenetic mechanisms of drug resistance of hematological cancers promoted by the bone marrow (BM) microenvironment. This proposal will investigate the transcriptional-regulatory role of a leucine-zipper transcription factor (TF) called CCAAT/enhancer-binding protein beta (C/EBPβ) in promoting de novo drug resistance of Multiple Myeloma (MM) in the context of the BM microenvironment. MM is a disease caused by malignant plasma B cells mainly residing in the BM. It is incurable largely because of the emergence of drug resistance. One important contribution to drug resistance stems from the protective effect of the BM microenvironment, which includes growth promoting soluble factors and physical interaction with cellular components such as stromal cells, osteoblasts, and matrices. The emergence of de novo drug resistance occurs in a short timeframe and is reversible, suggesting epigenetic mechanisms may be an important driver. However, the mechanisms of chromatin regulators contributing to de novo drug resistance of MM in the BM microenvironment remain largely unexplored. Our work predicted C/EBPβ as a key transcription regulator of target genes of signaling pathways activated by the BM stromal cells. The BM stromal cells induced a genome- wide reprogramming in gene expression (transcriptome) and chromatin accessibility (regulome) of MM cells, mainly driven by soluble factors. Integrative analysis with ENCODE genomic binding data indicated C/EBPβ as a major contributor to the BM stromal cell-induced transformation of transcriptome and regulome. Our preliminary results defined C/EBPβ as a promising subject to understand epigenetic mechanisms for the emergence of de novo drug resistance in MM. We hypothesize that C/EBPβ modulates chromatin accessibility for transcriptional regulation, and through which contributes to soluble factor-mediated drug resistance in MM cells. We will test this hypothesis from two directions. In AIM 1, we will first validate the growth-promoting role of C/EBPβ using CRISPR KO of CEBPB in MM cell lines combined with engraftment model in immunodeficient NSG mice. Then we will define soluble factor-induced signature genes regulated by C/EBPβ through an integrative analysis of genome-wide profiles of gene expression and accessible chromatin. In AIM 2, we will examine the impact of C/EBPβ loss on soluble factor-mediated drug resistance to IMiDs and define the underlying genome-wide transcription signatures linked to the resistance and regulated by C/EBPβ. Results from this proposal will establish whether targeting the C/EBPβ pathway is a rational method for the development of novel therapeutic strategies to suppress de novo drug resistance as promoted by the BM microenvironment for MM cells.