KLF5 downregulation desensitizes castration-resistant prostate cancer cells to docetaxel by increasing BECN1 expression and inducing cell autophagy
KLF5 downregulation desensitizes castration-resistant prostate cancer cells to docetaxel by increasing BECN1 expression and inducing cell autophagy
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KLF5 下调通过增加 BECN1 表达和诱导细胞自噬使去势抵抗性前列腺癌细胞对多西紫杉醇脱敏
DOI：
10.7150/thno.33282
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发表时间：
2019-01-01
期刊：
影响因子：
12.4
通讯作者：
Guo, Peng
中科院分区：
文献类型：
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作者：
Jia, Jing;Zhang, Hai-Bao;Guo, Peng
KLF 5在前列腺癌中经常缺失或下调。然而，目前尚不清楚KLF 5的下调是否与前列腺癌细胞对化疗的反应和/或患者的预后有关。研究方法：我们通过MTT和集落形成试验监测细胞生长，通过串联荧光显微镜和透射电子显微镜监测细胞自噬。通过RT-qPCR和Western印迹分析基因表达。我们通过ChIP测定、寡核苷酸下拉和免疫共沉淀确定了KLF 5与HDAC 3在beclin-1（BECN 1）启动子上的结合。在CWR 22 RV 1异种移植肿瘤小鼠模型中检查多西他赛对体内细胞生长的影响。结果：在本研究中，我们发现KLF 5下调与前列腺癌的进展和患者的预后不良有关。KLF 5基因敲低可降低前列腺癌细胞对多西他赛的体外和体内敏感性，多西他赛治疗可降低KLF 5的表达。此外，我们证实多西他赛治疗通过诱导前列腺癌细胞中的自噬来抑制细胞死亡。因此，我们假设KLF 5可能是细胞自噬的调节因子。有趣的是，KLF 5可以通过与HDAC 3协同抑制BECN 1的转录来抑制前列腺癌细胞自噬。另一个重要发现是多西他赛治疗通过AMPK/mTOR/p70 S6 K信号通路抑制KLF 5表达，导致BECN 1增加，诱导细胞自噬，并促进去势抵抗性前列腺癌细胞的细胞存活。结论：我们的研究结果表明，下调KLF 5促进细胞自噬在前列腺癌。此外，减少KLF 5还促进多西他赛诱导的细胞自噬，导致对药物的脱敏和细胞存活。KLF 5水平降低导致BECN 1通过AMPK/mTOR/p70 S6 K信号传导增加。因此，抑制BECN 1和细胞自噬对于KLF 5增加前列腺癌细胞对多西他赛的敏感性至关重要。
KLF5 is frequently deleted or downregulated in prostate cancer. However, it is not known whether downregulation of KLF5 is associated with the response of prostate cancer cells to chemotherapy and/or prognosis of patients. Methods: We monitored cell growth by MTT and colony formation assays, and cell autophagy through tandem fluorescence microscopy and transmission electron microscopy. Gene expression was analyzed by RT-qPCR and Western blotting. We determined the binding of KLF5 together with HDAC3 on the beclin-1 (BECN1) promoter by the ChIP assay, oligonucleotides pulldown, and co-immunoprecipitation. The effect of docetaxel on cell growth in vivo was examined in a CWR22RV1 xenograft tumor mouse model. Results: In the present study, we found that KLF5 down-regulation was associated with progression of prostate cancer and poor prognosis of patients. KLF5 knockdown reduced the sensitivity of prostate cancer cells to docetaxel in vitro and in vivo, and docetaxel treatment decreased the expression of KLF5. Moreover, we confirmed that docetaxel treatment inhibited cell death by inducing autophagy in prostate cancer cells. Thus, we hypothesized that KLF5 could be a regulator of cell autophagy. Interestingly, KLF5 could inhibit prostate cancer cell autophagy by suppressing the transcription of BECN1 cooperatively with HDAC3. Another significant finding was that docetaxel treatment repressed KLF5 expression through AMPK/mTOR/p70S6K signaling pathway resulting in increased BECN1, induction of cell autophagy, and promotion of cell survival in castration-resistant prostate cancer cells. Conclusions: Our results indicated that downregulation of KLF5 promoted cell autophagy in prostate cancer. Furthermore, reduced KLF5 also facilitated cell autophagy induced by docetaxel resulting in desensitization to the drug and cell survival. Decreased levels of KLF5 led to increased BECN1 via AMPK/mTOR/p70S6K signaling. Thus, repression of BECN1 and cell autophagy was critical for KLF5 to increase the sensitivity of prostate cancer cells to docetaxel.