Blocked Autophagy Using Lysosomotropic Agents Sensitizes Resistant Prostate Tumor Cells to the Novel Akt Inhibitor AZD5363
Blocked Autophagy Using Lysosomotropic Agents Sensitizes Resistant Prostate Tumor Cells to the Novel Akt Inhibitor AZD5363
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DOI：
10.1158/1078-0432.ccr-12-3114
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发表时间：
2013-02-15
影响因子：
11.5
通讯作者：
Zoubeidi, Amina
中科院分区：
文献类型：
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作者：
Lamoureux, Francois;Thomas, Christian;Zoubeidi, Amina
目的：前列腺癌的发展通常与肿瘤抑制性磷酸酶和张力蛋白同源物（PTEN）的缺失或沉默相关，所述肿瘤抑制性磷酸酶和张力蛋白同源物是磷酸肌醇3激酶（PI 3 K）-Akt途径的负调节剂，导致在临床前和临床环境中对各种疗法的抗性。因此，PI 3 K-Akt通路在促进可促成恶性表型的存活信号传导的各种细胞过程中起核心作用，并且因此是有吸引力的药理学靶标。然而，作为单一的代理商，AKT抑制剂的疗效可能会受到限制的阻力机制，导致在最小的细胞死亡在tumor cells.Experimental Design：我们调查的Akt抑制剂AZD 5363对细胞增殖，细胞周期，凋亡和Akt下游通路蛋白的影响。研究了AZD 5363诱导的存活机制。然后，我们检查了自噬抑制与AZD 5363组合对细胞增殖和凋亡的影响。此外，在PC-3前列腺癌异种移植物中评估了自噬的溶酶体抑制剂（氯喹）与Akt抑制剂AZD 5363的联合治疗的抗癌活性。结果：在这里，我们表明Akt抑制剂AZD 5363通过减少p-mTOR、p-P70 S6 K和p-S6 K来影响Akt下游通路。虽然AZD 5363单药治疗诱导G（2）生长停滞和自噬，但它未能诱导PC-3和DU 145前列腺癌细胞系的显著凋亡。在这些肿瘤前列腺细胞系中，使用药理学抑制剂（3-甲基腺嘌呤、氯喹和巴弗洛霉素A）或遗传抑制剂（靶向Atg 3和Atg 7的siRNA）阻断自噬增强了Akt抑制剂AZD 5363诱导的细胞死亡。重要的是，在PC 3异种移植瘤中，与对照组相比，AZD 5363与氯喹联合用药显著减小了84.9%的肿瘤体积，与单独使用任一种药物相比，减小了77.5%。综合起来看，这些数据显示Akt抑制剂AZD 5363与自噬的溶酶体抑制剂氯喹协同作用，在前列腺癌模型中诱导细胞凋亡并延迟肿瘤进展，对AZD 5363单药治疗耐药，提供了一种可能适用于患者的新治疗方法。临床癌症研究; 19（4）; 833-44。(c)2012年AACR。
Purpose: Prostate cancer development is often associated with deletion or silencing of tumor suppressor phosphatase and tensin homolog (PTEN), a negative regulator of the phosphoinositide 3 kinase (PI3K)-Akt pathway, leading to resistance to various therapies in both the preclinical and clinical setting. Therefore, the PI3K-Akt pathway plays a central role in various cellular processes promoting survival signaling that can contribute to the malignant phenotype, and, consequently, is an attractive pharmacologic target. However, as single agents, the efficacy of AKT inhibitors may be limited by resistance mechanisms that result in minimal cell death in tumor cells.Experimental Design: We investigated the effects of the Akt inhibitor AZD5363 on cell proliferation, cell cycle, apoptosis, and Akt downstream pathway proteins. Survival mechanisms induced by AZD5363 were investigated. We then examined the impacts of inhibition of autophagy in combination with AZD5363 on cell proliferation and apoptosis. Furthermore, the anticancer activity of combination treatment of the lysosomotropic inhibitor of autophagy (chloroquine) with the Akt inhibitor AZD5363 was evaluated in PC-3 prostate cancer xenografts.Results: Here, we show that the Akt inhibitor AZD5363 affected the Akt downstream pathway by reducing p-mTOR, p-P70S6K, and p-S6K. While AZD5363 monotherapy induced G(2) growth arrest and autophagy, it failed to induce significant apoptosis in PC-3 and DU145 prostate cancer cell lines. Blocking autophagy using pharmacologic inhibitors (3-methyladenine, chloroquine, and bafilomycin A) or genetic inhibitors (siRNA targeting Atg3 and Atg7) enhanced cell death induced by Akt inhibitor AZD5363 in these tumor prostate cell lines. Importantly, the combination of AZD5363 with chloroquine significantly reduced tumor volume by 84.9% compared with the control group and by 77.5% compared with either drug alone in PC3 xenografts.Conclusion: Taken together, these data show that the Akt inhibitor AZD5363 synergizes with the lysosomotropic inhibitor of autophagy chloroquine to induce apoptosis and delay tumor progression in prostate cancer models that are resistant to monotherapy AZD5363, providing a new therapeutic approach potentially translatable to patients. Clin Cancer Res; 19(4); 833-44. (c) 2012 AACR.