PKC inhibitor Go6976 induces mitosis and enhances doxorubicin-paclitaxel cytotoxicity in urinary bladder carcinoma cells
PKC inhibitor Go6976 induces mitosis and enhances doxorubicin-paclitaxel cytotoxicity in urinary bladder carcinoma cells
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DOI：
10.1016/j.canlet.2007.01.011
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发表时间：
2007-08-08
期刊：
影响因子：
9.7
通讯作者：
Peltonen, Juha
中科院分区：
文献类型：
--
作者：
Aaltonen, Vesa;Koivunen, Jussi;Peltonen, Juha
蛋白激酶C(PKC)α/βI同工酶抑制剂Go6976被认为是通过直接抑制Chk1而取消G2检查点的。在本研究中，我们发现Go6976可诱导经阿霉素处理的5637膀胱移行细胞癌细胞有丝分裂，有趣的是，也可诱导非同步5637细胞有丝分裂。重要的是，结果表明阿霉素处理的癌细胞和非同步癌细胞都被Go6976强迫有丝分裂。然而，部分细胞避免了有丝分裂中的死亡，并持续在细胞周期中，这可能会增加基因组不稳定的可能性。进一步研究了Go6976单独及与化疗药物合用的细胞毒性。Go6976单独处理可诱导细胞凋亡。阿霉素诱导G2期停滞，并抑制有丝分裂特异性药物紫杉醇的细胞毒作用。多柔比星-紫杉醇和多柔比星-紫杉醇联合应用可显著增强多柔比星-紫杉醇和多柔比星-Go6976序列的细胞毒作用。在阿霉素-Go6976+紫杉醇序列中，紫杉醇使细胞停止有丝分裂，抑制了不利的细胞周期进程。对GC，6976诱导有丝分裂的分子机制的分析表明，PKC抑制浓度的GC，6976在非同步化和DNA损伤的细胞中以浓度依赖的方式诱导cdc2激活。同时，在DNA损伤细胞中，Chk1/2失活，cdc25C激活，表明上游发生了调控事件。在非同步化细胞中，可观察到cdc25C的激活，而不是Chk1/2的激活，提示c-TAK 1失活。本研究结果表明，Go6976与阿霉素和紫杉醇联合使用时具有协同的细胞毒作用。(C)2007爱思唯尔爱尔兰有限公司。保留所有权利。
Protein kinase C (PKC) alpha/beta I isoenzyme inhibitor Go6976 has been suggested to be a G2 checkpoint abrogator by direct Chk1 inhibition. In the present study, we den-ionstrate that Go6976 induces mitosis in doxorubicin treated G2-arrested 5637 urinary bladder transitional cell carcinoma cells and interestingly also in non-synchronized 5637 cells. Importantly, the results demonstrated that both doxorubicin treated and non-synchronized cancer cells are forced to mitosis by Go6976. However, part of the cells avoid the death in mitosis and continue in the cell cycle which may increase the probability of genomic instability. Cytotoxicity of Go6976 alone and in combination with chemotherapeutic agents was further studied. Go6976 treatment alone induced apoptotic cell death. Cytostatic doxorubicin pre-treatment induced G2 arrest and inhibited the cytotoxic effects of mitosis specific drug paclitaxel. Cytotoxicities of doxorubicin-paclitaxel and doxorubicin-Go6976 sequences could be markedly enhanced by combining Go6976 with paclitaxel after doxorubicin pre-treatment. In doxorubicin-Go6976+paclitaxel sequence, paclitaxel arrested the cells to mitosis and unfavourable progression of the cell cycle was inhibited. Analyzes of the molecular mechanisms underlying Gc,6976 induced mitosis showed that PKC inhibiting, concentrations of Gc,6976 induced cdc2 activation concentration-dependently in non-synchronized and in DNA damaged cells. Simultaneously, Chk1/2 became deactivated and cdc25C activated in DNA damaged cells, indicating regulatory events upstream. In non-synchronized cells, activation of cdc25C, but not Chk1/2, was observed, suggesting inactivation of c-TAK 1. The results of the current study suggest that Go6976 has a synergistic cytotoxic effect when combined with doxorubicin and paclitaxel. (C) 2007 Elsevier Ireland Ltd. All rights reserved.