膀胱癌是人群中常见的恶性肿瘤，美国一肿瘤中心预测2016年该国约有76000例新发膀胱癌患者，其中16000例左右死于该疾病。在欧美，膀胱癌是男性发病率第四位、死亡率第八位的恶性肿瘤。随着我国的工业化进程，其发病率有上升趋势。由于膀胱癌具有高复发性，目前是世界范围内人均治疗成本最高的恶性肿瘤。

　　肿瘤的发生十分复杂，包括癌基因的激活及抑癌基因的失活。肿瘤的生长、进展及转移与其所处微环境、功能代谢及机体的免疫状态密切相关。CK2（Casein kinase 2）是一种保守的蛋白激酶，广泛分布于真核生物细胞中，其磷酸化底物具有多样性。这些底物在DNA复制与转录、细胞代谢与RNA翻译、细胞的增殖与分化调节方面起重要作用。

　　我们团队一直致力于膀胱癌的基础和临床研究。我们分析了22对膀胱癌与其临近正常组织的CK2表达，发现无论是RNA水平还是蛋白水平，CK2α在肿瘤组织中表达都一致性升高。在正常膀胱细胞株和7个肿瘤细胞株比较研究中也有类似的发现。我们进一步应用组织芯片，运用免疫组化方法研究了160例膀胱癌组织中CK2α的表达，发现其表达的差异与肿瘤细胞的恶性程度相关。而运用生物学的方法抑制CK2α的表达可以显著降低膀胱癌细胞的增殖、迁移，提高膀胱癌细胞的凋亡率。

　　肿瘤细胞的无氧糖酵解被认为是肿瘤细胞能量代谢的重要方式。我们研究发现在抑制CK2α表达后。肿瘤糖代谢中一些关键转运蛋白（葡萄糖转运蛋白1）及代谢途径中的关键酶HK1、HK2、PKM发生了改变，提示CK2α可能通过调节肿瘤细胞的能量代谢改变膀胱癌细胞的生物学特性。本研究首次发现膀胱癌中CK2α与代谢相关。这一发现可能为膀胱癌的治疗带来新思路。

吕强  副教授

　　医学博士，美国约翰霍普金斯大学博士后，主任医师，硕士生导师，南京医科大学第一附属医院（江苏省人民医院）泌尿外科副主任。任中华医学会泌尿外科学分会国际交流学组委员，江苏省医学会泌尿外科学分会肿瘤学组委员，南京医学会泌尿外科专业委员会委员兼秘书，《中华实验外科杂志》特约编委，全国高等教育医学数字化规划教材（国家医学电子书包）《外科学》编委。主持多项国家和江苏省研究项目。

　　研究摘要

287  Targeting protein kinase CK2 suppresses bladder cancer cell survival via glucolysis pathway

Introduction & Objectives：Bladder cancer is a common malignancy involving urinary tract. Although great progressions have been made in treating this deadly cancers， clinical trials of molecular target therapy in bladder cancer were still discouraging. Casein kinase 2 (CK2) is a constitutively active serine/threonine kinase that promotes cell proliferation and resists apoptosis through many pathways. Elevated CK2 expression has been demonstrated in some solid tumours. Here we reported its role in urinary bladder cancer.

Material & Methods：Protein and mRNA levels of CK2α were detected by quantitative RT-PCR and Western blot in bladder urothelial carcinoma samples and cell lines. siRNA or CX-4945 (small-molecule CK2α inhibitor) were used to inhibit CK2α in bladder cancer cell lines T24 and EJ. Inhibited CK2α expression and transcriptional activity were verified by RT-PCR and Western blot. Cell proliferation was assessed by MTT assay and cell apoptosis was measured by flow cytometry after treatment with siRNA or CX-4945. AKT/mTOR and glucolysis pathway were measured by Western blot and RT-PCR.

Results：The expression of CK2α in bladder cancer is elevated in tumour tissues than in adjacent normal tissues. The expression levels of glycolysis-related genes [glucose transporter (GLUT)1， lactic dehydrogenase (LDH)A， LDHB， hexokinase (HK)1， HK2 and pyruvate kinase type M (PKM) were higher in tumour tissues as well in our previous study.?Knock-down of CK2α by siRNA in bladder cancer cell lines resulted in reduction in tumour aerobic glycolysis. Decrease in glucose uptake and lactate production were observed， accompanied with lower phosphorylated AKT and deactivated mTOR. Protein and mRNA expression levels of glycolysis-related genes were also decreased in CK2α knock-down cells compared to control. Moreover， low level of CK2α suppressed cell growth and induced apoptosis. Results could be reproduced after treatment with CK2α inhibitor CX-4945 in both cell lines with a dose dependent response.

Conclusions：Thus， we report for the first time that over-expressed CK2α positively regulate glucose metabolism in human bladder cancer cells， participate in regulation of cell survival subsequently. Blocking CK2 function may provide novel diagnostic and therapeutic strategies for the treatment of bladder cancer.