Department of Human and Animal Cell Lines, Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany.
PLoS One. 2021 Nov 22;16(11):e0259674. doi: 10.1371/journal.pone.0259674. eCollection 2021.
T-box genes encode transcription factors which control basic processes in development of several tissues including cell differentiation in the hematopoietic system. Here, we analyzed the physiological activities of all 17 human T-box genes in early hematopoiesis and in lymphopoiesis including developing and mature B-cells, T-cells, natural killer (NK)-cells and innate lymphoid cells. The resultant expression pattern comprised six genes, namely EOMES, MGA, TBX1, TBX10, TBX19 and TBX21. We termed this gene signature TBX-code which enables discrimination of normal and aberrant activities of T-box genes in lymphoid malignancies. Accordingly, expression analysis of T-box genes in Hodgkin lymphoma (HL) patients using a public profiling dataset revealed overexpression of EOMES, TBX1, TBX2, TBX3, TBX10, TBX19, TBX21 and TBXT while MGA showed aberrant downregulation. Analysis of T-cell acute lymphoid leukemia patients indicated aberrant overexpression of six T-box genes while no deregulated T-box genes were detected in anaplastic large cell lymphoma patients. As a paradigm we focused on TBX3 which was ectopically activated in about 6% of HL patients analyzed. Normally, TBX3 is expressed in tissues like lung, adrenal gland and retina but not in hematopoiesis. HL cell line KM-H2 expressed enhanced TBX3 levels and was used as an in vitro model to identify upstream regulators and downstream targets in this malignancy. Genomic studies of this cell line showed focal amplification of the TBX3 locus at 12q24 which may underlie its aberrant expression. In addition, promoter analysis and comparative expression profiling of HL cell lines followed by knockdown experiments revealed overexpressed transcription factors E2F4 and FOXC1 and chromatin modulator KDM2B as functional activators. Furthermore, we identified repressed target genes of TBX3 in HL including CDKN2A, NFKBIB and CD19, indicating its respective oncogenic function in proliferation, NFkB-signaling and B-cell differentiation. Taken together, we have revealed a lymphoid TBX-code and used it to identify an aberrant network around deregulated T-box gene TBX3 in HL which promotes hallmark aberrations of this disease. These findings provide a framework for future studies to evaluate deregulated T-box genes in lymphoid malignancies.
T 盒基因编码转录因子，这些转录因子控制包括造血系统细胞分化在内的几种组织的基本发育过程。在这里，我们分析了 17 个人类 T 盒基因在早期造血和淋巴发生中的生理活性，包括正在发育和成熟的 B 细胞、T 细胞、自然杀伤 (NK)-细胞和固有淋巴细胞。由此产生的表达模式包括 6 个基因，即 EOMES、MGA、TBX1、TBX10、TBX19 和 TBX21。我们将这个基因特征命名为 TBX 代码，它能够区分淋巴恶性肿瘤中 T 盒基因的正常和异常活性。因此，使用公共分析数据集对霍奇金淋巴瘤 (HL) 患者的 T 盒基因表达分析显示 EOMES、TBX1、TBX2、TBX3、TBX10、TBX19、TBX21 和 TBXT 过度表达，而 MGA 显示异常下调。对 T 细胞急性淋巴细胞白血病患者的分析表明，六个 T 盒基因异常过表达，而在间变性大细胞淋巴瘤患者中未检测到异常的 T 盒基因。作为一个范例，我们重点研究了在分析的约 6%的 HL 患者中异位激活的 TBX3。正常情况下，TBX3 在肺、肾上腺和视网膜等组织中表达，但不在造血组织中表达。HL 细胞系 KM-H2 表达增强的 TBX3 水平，并被用作体外模型，以确定该恶性肿瘤中的上游调节剂和下游靶标。对该细胞系的基因组研究显示，12q24 处的 TBX3 基因座发生了局灶性扩增，这可能是其异常表达的基础。此外，对 HL 细胞系进行启动子分析和比较表达谱分析，然后进行敲低实验，发现过度表达的转录因子 E2F4 和 FOXC1 以及染色质调节剂 KDM2B 是功能激活剂。此外，我们在 HL 中鉴定了 TBX3 的受抑靶基因，包括 CDKN2A、NFKBIB 和 CD19，表明其在增殖、NFkB 信号传导和 B 细胞分化方面的各自致癌功能。总之，我们揭示了一个淋巴 TBX 代码，并利用它来识别 HL 中异常调节的 T 盒基因 TBX3 周围的异常网络，该网络促进了这种疾病的标志性异常。这些发现为未来评估淋巴恶性肿瘤中异常调节的 T 盒基因的研究提供了框架。
