同源异型盒基因编码调节组织特异性分化过程的发育转录因子,并在失调时驱动癌症发生。树突状细胞(DC)是髓系免疫细胞,存在两种类型,常规或类浆细胞DC。最近,我们表明,NKL亚类同源异型盒基因VENTX的表达仅限于常规DC,调节发育基因。这里,我们鉴定并研究了在浆细胞样DC(pDC)和衍生的母细胞性浆细胞样树突状细胞肿瘤(BPDCN)中特异性表达的同源异型盒基因.我们分析了基因表达数据,进行RQ-PCR,蛋白质印迹和免疫细胞学分析,siRNA介导的敲低测定和随后的RNA测序和活细胞成像。公开基因表达数据的筛选揭示了CUT类同源异型盒基因CUX2在pDC中的限制性活性。在骨髓生成中对该同源盒基因类别的扩展分析表明,其他CUX2活性仅限于骨髓祖细胞,而BPDCN患者异常表达ONECUT2,在完整的髓系区室中保持沉默。表达ONECUT2的BPDCN细胞系CAL-1用作研究其调控和致癌活性的模型。18q21的ONECUT2基因座被IRF4,AUTS2和TNF信号重复并激活,并被BMP4-抑制,TGFb-和IL13-信号。ONECUT2的功能分析揭示了pDC分化和CDKN1C和CASP1表达的抑制,而SMAD3和EPAS1被激活。EPAS1反过来增强了在低氧条件下的存活,因此可以支持存在于低氧皮肤损伤中的树突状肿瘤细胞。总的来说,我们揭示了CUT类同源异型盒基因在包括pDCs在内的骨髓生成和BPDCN中的生理和异常活性,分别。我们的数据可能有助于BPDCN患者的诊断,并揭示这种致命恶性肿瘤的新治疗靶标。
Homeobox genes encode developmental transcription factors regulating tissue-specific differentiation processes and drive cancerogenesis when deregulated. Dendritic cells (DCs) are myeloid immune cells occurring as two types, either conventional or plasmacytoid DCs. Recently, we showed that the expression of NKL-subclass homeobox gene VENTX is restricted to conventional DCs, regulating developmental genes. Here, we identified and investigated homeobox genes specifically expressed in plasmacytoid DCs (pDCs) and derived blastic plasmacytoid dendritic cell neoplasm (BPDCN). We analyzed gene expression data, performed RQ-PCR, protein analyses by Western blot and immuno-cytology, siRNA-mediated knockdown assays and subsequent RNA-sequencing and live-cell imaging. Screening of public gene expression data revealed restricted activity of the CUT-class homeobox gene CUX2 in pDCs. An extended analysis of this homeobox gene class in myelopoiesis showed that additional CUX2 activity was restricted to myeloid progenitors, while BPDCN patients aberrantly expressed ONECUT2, which remained silent in the complete myeloid compartment. ONECUT2 expressing BPDCN cell line CAL-1 served as a model to investigate its regulation and oncogenic activity. The ONECUT2 locus at 18q21 was duplicated and activated by IRF4, AUTS2 and TNF-signaling and repressed by BMP4-, TGFb- and IL13-signalling. Functional analyses of ONECUT2 revealed the inhibition of pDC differentiation and of CDKN1C and CASP1 expression, while SMAD3 and EPAS1 were activated. EPAS1 in turn enhanced survival under hypoxic conditions which thus may support dendritic tumor cells residing in hypoxic skin lesions. Collectively, we revealed physiological and aberrant activities of CUT-class homeobox genes in myelopoiesis including pDCs and in BPDCN, respectively. Our data may aid in the diagnosis of BPDCN patients and reveal novel therapeutic targets for this fatal malignancy.