Authors' Affiliations: The Gade Institute, Broegelmann Research Laboratory, Department of Clinical Science, Department of Medicine, University of Bergen; Departments of Microbiology and Pathology, Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital; KinN Therapeutics AS, Bergen, Norway; College of Pharmacy, Second Military Medical University, Shanghai, PR China; Institute of Pathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; Zhejiang-California International NanoSystems Institute, Zhejiang University, Hangzhou, PR China; Swedish Medical Center; and Department of Urology, University of Washington, Seattle, Washington.
Cancer Res. 2013 Dec 1;73(23):7090-100. doi: 10.1158/0008-5472.CAN-13-1560. Epub 2013 Oct 7.
How prostate cancer is initiated remains a topic of debate. In an effort to establish a human model of prostate carcinogenesis, we adapted premalignant human prostate EPT2-D5 cells to protein-free medium to generate numerous tight prostate spheres (D5HS) in monolayer culture. In contrast to EPT2-D5 cells, the newly generated D5HS efficiently formed large subcutaneous tumors and subsequent metastases in vivo, showing the tumorigenicity of D5HS spheres. A striking production of interleukin (IL)-6 mRNA and protein was found in D5HS cells. The essential roles of IL-6 and the downstream STAT3 signaling in D5HS tumor sphere formation were confirmed by neutralizing antibody, chemical inhibitors, and fluorescent pathway reporter. In addition, elevated reactive oxygen species (ROS) produced upon protein depletion was required for the activation of IL-6/STAT3 in D5HS. Importantly, a positive feedback loop was found between ROS and IL-6 during tumor sphere formation. The association of ROS/IL-6/STAT3 to the carcinogenesis of human prostate cells was further examined in xenograft tumors and verified by limiting dilution implantations. Collectively, we have for the first time established human prostate tumor-initiating cells based on physiologic adaption. The intrinsic association of ROS and IL-6/STAT3 signaling in human prostate carcinogenesis shed new light on this relationship and define therapeutic targets in this setting.
前列腺癌的起始机制仍然存在争议。为了建立人类前列腺癌发生的模型，我们使具有癌前病变的人前列腺 EPT2-D5 细胞适应无蛋白培养基，在单层培养中生成许多紧密的前列腺球体（D5HS）。与 EPT2-D5 细胞相比，新生成的 D5HS 能有效地在体内形成大的皮下肿瘤和随后的转移，显示出 D5HS 球体的致瘤性。在 D5HS 细胞中发现白细胞介素（IL）-6 mRNA 和蛋白的大量产生。通过中和抗体、化学抑制剂和荧光通路报告证实了 IL-6 和下游 STAT3 信号在 D5HS 肿瘤球体形成中的重要作用。此外，在蛋白耗竭时产生的升高的活性氧（ROS）对于 D5HS 中 IL-6/STAT3 的激活是必需的。重要的是，在肿瘤球体形成过程中发现了 ROS 和 IL-6 之间的正反馈环。在异种移植肿瘤中进一步检查了 ROS/IL-6/STAT3 与人前列腺细胞癌变之间的关联，并通过有限稀释植入进行了验证。总之，我们首次基于生理适应建立了人前列腺肿瘤起始细胞。ROS 和 IL-6/STAT3 信号在人类前列腺癌发生中的内在关联为这一关系提供了新的视角，并确定了这一背景下的治疗靶点。
