|
|
|
鼻咽癌细胞中LMP1增强k内含子增强子的活性并通过NF-kB和AP-1通路上调免疫球蛋白k轻链的表达 |
|
|
|
|
|
LMP1-augmented kappa intron enhancer activity contributes to upregulation expression of Ig kappa light chain via NF-kappaB and AP-1 pathways in nasopharyngeal carcinoma cells |
|
|
|
|
|
Liu H, Zheng H, Duan Z, Hu D, Li M, Liu S, Li Z, Deng X, Wang Z, Tang M, Shi Y, Yi W, Cao Y 2009/12/22 13:51:00 |
|
【发表评论】
|
|
|
|
打印|
推荐给好友
|
|
|
Molecular Cancer, 2009, Volume 8,
|
|
|
|
|
|
|
Background: Expression of kappa gene is under the control of distinct cis-regulatory elements, including the kappa intron enhancer (iEκ) and the kappa 3' enhancer (3'Eκ). The active enhancers and expression of immunoglobulin is generally considered to be restricted to B lymphocytes. However, accumulating evidence indicated that epithelial cancer cells, including nasopharyngeal carcinoma (NPC) cell lines, express immunoglobulins. The mechanisms underlying the expression of Igs in nonlymphoid cells remain unknown. On the basis of our previous finding that expression of kappa light chain in NPC cells can be upregulated by EBV-encoded latent membrane protein 1(LMP1) through the activation of NF-κB and AP-1 signaling pathways, we thus use NPC cells as model to further explore the molecular mechanisms of nonlymphoid cells expressing Ig kappa. Results: In this study, luciferase reporter plasmid containing human wild-type iEκ, and its derivative plasmids containing mutant binding sites for transcription factor NF-κB or AP-1 were constructed. Luciferase reporter assays demonstrate iEκis active in Igκ-expressing NPC cells and LMP1 expression can upregulate the activity of iEκin NPC cells. Mutation of the NF-κB or AP-1 site within and downstream the iEκ, inhibition of the NF-κB and AP-1 pathways by their respective chemical inhibitor Bay11-7082 and SP600125 as well as stable or transient expression of dominant-negative mutant of IκBα (DNMIκBα) or of c-Jun (TAM67) indicate that both sites are functional and LMP1-enhanced iEκactivity is partly regulated by these two sites. Gel shift assays show that LMP1 promotes NF-κB subunits p52 and p65 as well as AP-1 family members c-Jun and c-Fos binding to the κNF-κB and the κAP-1 motifs in vitro, respectively. Both chemical inhibitors and dominant negative mutants targeting for NF-κB and AP-1 pathways can attenuate the LMP1-enhanced bindings. Co-IP assays using nuclear extracts from HNE2-LMP1 cells reveal that p52 and p65, c-Jun and c-Fos proteins interact with each other at endogenous levels. ChIP assays further demonstrate p52 and p65 binding to the κB motif as well as c-Jun and c-Fos binding to the AP-1 motif of Ig kappa gene in vivo. Conclusion: These results suggest that human iEκis active in Igκ-expressing NPC cells and LMP1-stimulated NF-κB and AP-1 activation results in an augmenting activation of the iEκ. LMP1 promotes the interactions of heterodimeric NF-κB (p52/p65) and heterodimeric AP-1 (c-Jun/c-Fos) transcription factors with the human iEκenhancer region are important for the upregulation of kappa light chain in LMP1-positive nasopharyngeal carcinoma cells. © 2009 Liu et al; licensee BioMed Central Ltd.
|
|
|
|
|
|
|
Correspondence Address: Cao, Y.; Cancer Research Institute, Xiangya School of Medicine, Central South University, Xiangya Road 110, Changsha, Hunan 410078, China; email:ycao98@public.cs.hn.cn |
|
|
|
|
|
|
|
|
|
|
请登录后发表评论,点击此处登录。
|
|
|
疾病资源中心
王燕燕 王曙
上海交通大学附属瑞金医院内分泌科
患者,女,69岁。2009年1月无明显诱因下出现乏力,当时程度较轻,未予以重视。2009年3月患者乏力症状加重,尿色逐渐加深,大便习惯改变,颜色变淡。4月18日入我院感染科治疗,诉轻度头晕、心慌,体重减轻10kg。无肝区疼痛,无发热,无腹痛、腹泻、腹胀、里急后重,无恶性、呕吐等。入院半月前于外院就诊,查肝功能:ALT 601IU/L,AST 785IU/L,TBIL 97.7umol/L,白蛋白 41g/L,甲状腺功能:游离T3 30.6pmol/L,游离T4 51.9pmol/L,心电图示快速房颤。
医学数据库
|