Wang Yan, An Ruihua, Dong Xuesong, Pan Shangha, Duan Guowen, Sun Xueying
Department of Urologic Surgery, First Clinical Medical School of Harbin Medical University, Harbin, China.
Urol Int. 2009;82(2):214-21. doi: 10.1159/000200803. Epub 2009 Mar 19.
Arsenic trioxide (ATO) is a potent antitumor agent used to treat acute promyelocytic leukemia, and recently solid tumors including bladder cancers. However, a mechanism to explain its antitumor activity in bladder cancers is unclear. Here, we investigated the role of protein kinase C (PKC) in ATO-induced apoptosis and inhibition of proliferation in bladder cancer cells.
T24 human bladder carcinoma cells were incubated with different concentrations of ATO in the presence or absence of PMA (PKC activator) or H7 (PKC inhibitor). Cell proliferation was assessed by MTT assay, and apoptosis by TUNEL and electron microscopy. Flow cytometry was used to analyze cell cycle distribution, radioimmunoassay to measure PKC activity, and Western blot analysis to detect caspase-3.
ATO inhibited proliferation and induced apoptosis of T24 cells in a dose-dependent manner, caused an increase of percentage of cells in the G(1) phase and a decrease in the S and G(2) phases, and upregulated the expression of activated caspase-3 and reduced PKC activity. These effects were abrogated by PMA, but enhanced by H7.
PKC is involved in the anticancer activity of ATO for T24 bladder cancer cells, suggesting that targeting the PKC pathway may represent a potential approach to enhance the efficacy of ATO to treat bladder cancers.
三氧化二砷（ATO）是一种用于治疗急性早幼粒细胞白血病以及近期用于包括膀胱癌在内的实体瘤的强效抗肿瘤药物。然而，其在膀胱癌中抗肿瘤活性的机制尚不清楚。在此，我们研究了蛋白激酶C（PKC）在ATO诱导的膀胱癌细胞凋亡及增殖抑制中的作用。
将T24人膀胱癌细胞与不同浓度的ATO共同孵育，同时存在或不存在佛波酯（PMA，PKC激活剂）或H7（PKC抑制剂）。通过MTT法评估细胞增殖，通过TUNEL法和电子显微镜评估细胞凋亡。采用流式细胞术分析细胞周期分布，采用放射免疫分析法测量PKC活性，采用蛋白质印迹分析检测半胱天冬酶-3。
ATO以剂量依赖性方式抑制T24细胞的增殖并诱导其凋亡，导致G(1)期细胞百分比增加，S期和G(2)期细胞百分比减少，并上调活化的半胱天冬酶-3的表达且降低PKC活性。这些作用被PMA消除，但被H7增强。
PKC参与了ATO对T24膀胱癌细胞的抗癌活性，这表明靶向PKC途径可能是增强ATO治疗膀胱癌疗效的一种潜在方法。
