SETD6 regulates NF-κB signaling in urothelial cell survival: Implications for bladder cancer.
SETD6 regulates NF-κB signaling in urothelial cell survival: Implications for bladder cancer.
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DOI：
10.18632/oncotarget.14750
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发表时间：
2017-02-28
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影响因子：
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通讯作者：
Ghosh R
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作者：
Mukherjee N;Cardenas E;Bedolla R;Ghosh R
非肌肉浸润性膀胱癌的复发率高达45-70%，其中约15%的患者在5年内进展为肌肉浸润性疾病。治疗中经常使用卡介苗（mycobacterium, Bacillus calmetet - guerin， BCG）诱导局部炎症，使反应性患者的肿瘤缓解。bcg治疗的NF-κB del/del基因型患者复发风险增加，提示NF-κB在膀胱癌中的重要作用。由于蛋白甲基转移酶在调节染色质结构和基因表达中起着关键作用，我们筛选了一系列的表观遗传修饰基因来鉴定正常尿路上皮细胞和膀胱癌细胞之间的差异表达。我们发现并证实了含有set结构域的蛋白甲基转移酶SETD6的高表达。SETD6在赖氨酸310位点单甲基化NF-κB-p65。我们的研究结果表明，原代尿路上皮细胞和正常膀胱组织几乎检测不到SETD6的信息和蛋白水平，SETD6在转化的尿路上皮细胞中升高，在膀胱癌细胞和组织中进一步升高。在转化的尿路上皮细胞中，过表达SETD6可提高细胞存活率和集落形成，而在癌细胞中，过表达SETD6可降低这两个参数。荧光素酶报告基因检测显示，SETD6诱导了典型的NF-κB信号通路。此外，利用催化SETD6和i -κB α突变体表明，SETD6通过影响p65信息、蛋白水平及其功能（由NF-κB靶基因表达增加决定）积极调节生存。我们的研究结果表明，SETD6在NF-κB调控中发挥重要作用，并可能在BCG治疗后NF-κB介导的局部炎症反应中发挥重要作用。
Non-muscle invasive bladder cancer has a high recurrence rate of 45-70%, progressing to muscle invasive disease in about 15% of those patients over a 5-year period. Administration of the mycobacterium, Bacillus Calmette-Guerin (BCG) that induces local inflammation resulting in tumor remission in responsive patients is frequently used for treatment. BCG-treated patients with NF-κB del/del genotype have an increased risk of recurrence suggesting an important role of NF-κB in bladder cancer. Since protein methyltransferases play critical roles in modulating chromatin structure and gene expression, we screened a focused array of epigenetic modification genes to identify differential expression between normal urothelial and bladder cancer cells. We found and validated high expression of the SET-domain-containing protein methyltransferase, SETD6. SETD6 monomethylates NF-κB-p65 at lysine 310. Our results show that primary urothelial cells and normal bladder tissue have nearly undetectable message and protein level of SETD6 that increases in transformed urothelial cells and is further increased in bladder cancer cells and tissues. Overexpression of SETD6 in transformed urothelial cells increased cell survival and colony formation while knockdown in cancer cells decreased both parameters. Luciferase reporter assays showed that SETD6 induced the canonical NF-κB signaling pathway. Further, the use of catalytic SETD6 and IκBα mutant shows that SETD6 positively regulates survival by affecting p65 message, protein level and its function as determined by increased expression of NF-κB target genes. Our findings suggest that SETD6 plays an important role in NF-κB regulation and may have an important role in NF-κB-mediated local inflammatory response following BCG treatment.