Department of Urology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
J Urol. 2013 Sep;190(3):1076-82. doi: 10.1016/j.juro.2013.01.050. Epub 2013 Jan 23.
Prior study demonstrated that HMGB1 release by urothelial carcinoma cells in response to bacillus Calmette-Guérin is required for an in vivo antitumor effect. We evaluated the direct effects of HMGB1 on the in vitro response of urothelial carcinoma cells to bacillus Calmette-Guérin.
Two human urothelial carcinoma cell lines were used to study the effect of exogenous HMGB1 alone and combined with bacillus Calmette-Guérin on the tumor cell response to bacillus Calmette-Guérin. Antibody mediated blockade of receptors for HMGB1 or HMGB1 protein was used to determine the contribution of paracrine HMGB1 release to bacillus Calmette-Guérin biological effects. Response end points evaluated included the activation of intracellular signaling pathways, gene transactivation and cytotoxicity.
Urothelial carcinoma cells expressed the receptor for HMGB1 signaling. Antibody blockade of the RAGE receptor confirmed the dependence of signaling in response to HMGB1 on RAGE function. Exogenous HMGB1 activated cell signaling pathways for NFκB, NRF2 and CEBP. Quantitative reverse transcriptase-polymerase chain reaction on a panel of bacillus Calmette-Guérin responsive genes revealed peak expression resulting from the combination of bacillus Calmette-Guérin and HMGB1. Blockade of paracrine HMGB1 released in response to bacillus Calmette-Guérin using HMGB1 and/or RAGE receptor blocking antibodies showed a significant decrease in gene expression relative to that of bacillus Calmette-Guérin alone. HMGB1 potentiated the cytotoxic effects of bacillus Calmette-Guérin.
HMGB1 released by urothelial carcinoma cells after bacillus Calmette-Guérin treatment functions as a paracrine factor to potentiate the urothelial carcinoma cell response to bacillus Calmette-Guérin. This paracrine activity likely contributes to the dependence of an in vivo tumor response on HMGB1 release.
先前的研究表明，在体内，膀胱癌细胞受到卡介苗刺激后释放高迁移率族蛋白 B1（HMGB1）是发挥抗肿瘤作用的必要条件。本研究评估了 HMGB1 对膀胱癌体外反应的直接影响。
本研究使用两种人膀胱癌细胞系，研究了单独使用外源性 HMGB1 以及联合使用卡介苗对肿瘤细胞对卡介苗反应的影响。采用抗体介导的方法阻断 HMGB1 受体，以确定 HMGB1 旁分泌释放对卡介苗生物学效应的贡献。评估的反应终点包括细胞内信号通路的激活、基因转录激活和细胞毒性。
膀胱癌细胞表达 HMGB1 信号转导受体。用阻断 RAGE 受体的抗体阻断试验证实，HMGB1 信号转导对 RAGE 功能的依赖。外源性 HMGB1 激活了 NFκB、NRF2 和 CEBP 细胞信号通路。对一组卡介苗反应基因的定量逆转录聚合酶链反应显示，卡介苗和 HMGB1 的联合作用导致基因表达达到峰值。用 HMGB1 和/或 RAGE 受体阻断抗体阻断卡介苗刺激后释放的旁分泌 HMGB1，与单独使用卡介苗相比，基因表达显著减少。HMGB1 增强了卡介苗的细胞毒性作用。
卡介苗处理后膀胱癌细胞释放的 HMGB1 作为旁分泌因子，增强了膀胱癌细胞对卡介苗的反应。这种旁分泌活性可能是体内肿瘤反应依赖于 HMGB1 释放的原因。
