Introduction

The development of cancer generally occurs as a result of various deregulated molecular mechanisms affecting the genes that can control normal cellular growth. Signal transducer and activator of transcription 3 (STAT3) pathway, once aberrantly activated can promote carcinogenesis by regulating the transcription of a number of oncogenic genes.

Objectives

Here, we evaluated the impact of fangchinoline (FCN) to attenuate tumor growth and survival through modulation of oncogenic STAT3 signaling pathway using diverse tumor cell lines and a xenograft mouse model.

Methods

To evaluate the action of FCN on STAT3 cascade, protein levels were analyzed by Western blot analysis and electrophoretic mobility shift assay (EMSA). Translocation of STAT3 was detected by immunocytochemistry. Thereafter, FCN-induced ROS was measured by GSH/GSSG assay and H2DCF-DA. FCN-induced apoptosis was analyzed using Western blot analysis and flow cytometry for various assays. Finally, anti-cancer effects of FCN in vivo was evaluated in a myeloma model.

Results

We noted that FCN abrogated protein expression levels of STAT3 and upstream signals (JAK1/2 and Src). In addition, FCN also attenuated DNA binding ability of STAT3 and its translocation into the nucleus. It altered the levels of upstream signaling proteins, increased SHP-1 levels, and induced substantial apoptosis in U266 cells. FCN also promoted an increased production of reactive oxygen species (ROS) and altered GSSG/GSH ratio in tumor cells. Moreover, FCN effectively abrogated tumor progression and STAT3 activation in a preclinical myeloma model.

Conclusion

Overall, this study suggests that FCN may have a tremendous potential to alter abnormal STAT3 activation and induce cell death in malignant cells along with causing the suppression of pathogenesis and growth of cancer through a pro-oxidant dependent molecular mechanism.

中文翻译：

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Fangchinoline 通过在多发性骨髓瘤模型中刺激氧化应激和靶向 SHP-1 蛋白来减少 STAT3 活化

介绍

癌症的发展通常是由于各种失调的分子机制影响可以控制正常细胞生长的基因而发生的。信号转导和转录激活因子 3 (STAT3) 通路一旦异常激活，可通过调节许多致癌基因的转录来促进致癌作用。

目标

在这里，我们使用不同的肿瘤细胞系和异种移植小鼠模型，通过调节致癌 STAT3 信号通路，评估了 fangchinoline (FCN) 对减弱肿瘤生长和存活的影响。

方法

为了评估 FCN 对 STAT3 级联的作用，通过蛋白质印迹分析和电泳迁移率变动分析 (EMSA) 分析蛋白质水平。通过免疫细胞化学检测STAT3的易位。此后，通过 GSH/GSSG 测定和 H2DCF-DA 测量 FCN 诱导的 ROS。使用蛋白质印迹分析和流式细胞术分析 FCN 诱导的细胞凋亡，用于各种测定。最后，在骨髓瘤模型中评估了FCN在体内的抗癌作用。

结果

我们注意到 FCN 消除了 STAT3 和上游信号（JAK1/2 和 Src）的蛋白质表达水平。此外，FCN 还减弱了 STAT3 的 DNA 结合能力及其向细胞核的易位。它改变了上游信号蛋白的水平，增加了 SHP-1 水平，并诱导了 U266 细胞的大量凋亡。FCN 还促进了肿瘤细胞中活性氧 (ROS) 产生的增加和 GSSG/GSH 比率的改变。此外，FCN 有效地消除了临床前骨髓瘤模型中的肿瘤进展和 STAT3 激活。

结论

总体而言，这项研究表明，FCN 可能具有改变异常 STAT3 激活和诱导恶性细胞死亡的巨大潜力，同时通过促氧化剂依赖性分子机制抑制癌症的发病机制和生长。