Gene expression profiling of the Se-Ax cell line following E2A reconstitution

The transcription factor E2A is essential for lymphocyte development. In this study, we describe a recurrent E2A gene deletion in at least 70% of patients with Sézary syndrome (SS), a subtype of T cell lymphoma. Loss of E2A results in enhanced proliferation and cell cycle progression via derepression of the proto-oncogene MYC and the cell cycle regulator CDK6. Furthermore, by examining the gene expression profile of SS cells following restoration of E2A expression, we identify a number of E2A-regulated genes that interfere with oncogenic signaling pathways including the Ras pathway. Several of these genes are down-regulated or lost in primary SS tumor cells. These data demonstrate a tumor suppressor function of E2A in human lymphoid cells and could help to develop new treatment strategies for human lymphomas with altered E2A activity. The E2A-deficient Sézary cell line Seax was transiently transfected with the E2A-expression constructs E47myc (a myc-tagged E47 construct) or E47-forced dimer (a construct coding for two covalently linked E47 molecules), respectively. Every experiment was performed as two replicates accompanied by control transfections with a Mock plasmid.

转录因子E2A对于淋巴细胞发育至关重要。本研究报道了在至少70%的塞扎里综合征（Sézary syndrome, SS，一种T细胞淋巴瘤亚型）患者中存在复发性E2A基因缺失。E2A缺失可通过解除原癌基因MYC及细胞周期调控因子CDK6的抑制，增强细胞增殖能力并加速细胞周期进程。此外，通过检测恢复E2A表达后的SS细胞的基因表达谱，本研究鉴定出多个受E2A调控的基因，这些基因可干扰包括Ras通路在内的致癌信号通路。其中部分基因在原发性SS肿瘤细胞中呈下调表达或完全缺失。上述数据证实了E2A在人类淋巴样细胞中的抑癌功能，可为开发针对E2A活性异常的人类淋巴瘤的新型治疗策略提供思路。本研究分别将E2A表达构建体E47myc（带myc标签的E47构建体）或E47强制二聚体（编码两个共价连接的E47分子的构建体）瞬时转染至E2A缺陷型塞扎里综合征细胞系Seax中。所有实验均设置两次生物学重复，并以Mock质粒转染作为对照。