IL-6 enriched lung cancer stem-like cell population by inhibition of cell cycle regulators via DNMT1 upregulation
IL-6 enriched lung cancer stem-like cell population by inhibition of cell cycle regulators via DNMT1 upregulation
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DOI：
10.1002/ijc.29033
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发表时间：
2015-02-15
影响因子：
6.4
通讯作者：
Hung, Shih-Chieh
中科院分区：
文献类型：
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作者：
Liu, Chen-Chi;Lin, Jiun-Han;Hung, Shih-Chieh
肿瘤受到富含炎性细胞因子、生长因子和趋化因子的微环境的影响，这些因子可促进肿瘤生长。白细胞介素-6（IL-6）是一种多功能细胞因子，被认为是免疫和炎症反应的调节剂。据报道，IL-6与不同类型癌症的肿瘤进展和化疗耐药性相关。在我们的研究中，我们证明了IL-6在球形培养基中培养的A549肺癌细胞中富集肺癌干细胞样细胞的特性。IL-6还通过增强细胞增殖促进A549细胞的球体形成和干细胞样特性。甲基化特异性聚合酶链反应（PCR）进行，并显示IL-6增加A549癌细胞中p53和p21的甲基化。Western blot分析和实时荧光定量PCR结果显示，IL-6可增加A549细胞DNA甲基转移酶1（DNMT 1）的表达，但对DNMT 3a和DNMT 3b的表达无影响。DNMT 1的敲除消除了IL-6介导的细胞周期调节因子的高甲基化和肺癌干细胞样特性的富集。总之，我们的研究首次表明，IL-6/JAK 2/STAT 3通路上调DNMT 1，并通过下调DNA超甲基化导致的p53和p21来增强癌症的发生和肺癌干细胞（CSC）的增殖。在阻断IL-6/JAK 2/STAT 3通路和抑制DNMT 1后，肺CSC的增殖减少，并且它们的球体形成和启动肿瘤生长的能力降低。这些数据表明，靶向IL-6/JAK 2/STAT 3信号通路和DNMT 1可能成为治疗肺癌的重要策略。白细胞介素-6的失调与肺癌的进展有关，但IL-6促进疾病进展的机制尚不完全清楚。在此，在细胞和肿瘤球模型中，由于IL-6/JAK 2/STAT 3通路活性，DNA甲基转移酶1（DNMT 1）上调，癌症发生和肺癌干细胞（CSC）增殖增强。DNMT 1上调导致DNA超甲基化和p53和p21下调。在阻断IL-6/JAK 2/STAT 3通路和抑制DNMT 1后，肺CSC的增殖、它们的球体形成和它们启动肿瘤生长的能力降低。
Tumors are influenced by a microenvironment rich in inflammatory cytokines, growth factors and chemokines, which may promote tumor growth. Interleukin-6 (IL-6) is a multifunctional cytokine and known as a regulator of immune and inflammation responses. IL-6 has also been reported to be associated with tumor progression and chemoresistance in different types of cancers. In our study, we demonstrated that IL-6 enriches the properties of lung cancer stem-like cells in A549 lung cancer cells cultured in spheroid medium. IL-6 also promotes sphere formation and stem-like properties of A549 cells by enhancing cell proliferation. Methylation-specific polymerase chain reaction (PCR) was performed and revealed that IL-6 increased methylation of p53 and p21 in A549 cancer cells. Western blot analysis and quantitative real-time PCR demonstrated that IL-6 increased the expression of DNA methyltransferase 1 (DNMT1) in A549 cells cultured in spheroid medium, but not the expression of DNMT3a or DNMT3b. Knockdown of DNMT1 eliminated IL-6-mediated hypermethylation of cell cycle regulators and enrichment of lung cancer stem-like properties. In conclusion, our study, for the first time, shows that the IL-6/JAK2/STAT3 pathway upregulates DNMT1 and enhances cancer initiation and lung cancer stem cell (CSC) proliferation by downregulation of p53 and p21 resulting from DNA hypermethylation. Upon blockage of the IL-6/JAK2/STAT3 pathway and inhibition of DNMT1, the proliferation of lung CSCs was reduced and their formation of spheres and ability to initiate tumor growth were decreased. These data suggest that targeting of the IL-6/JAK2/STAT3 signaling pathway and DNMT1 may become important strategies for treating lung cancer.What's new? Dysregulation of interleukin-6 is implicated in the progression of lung cancer, but the mechanisms by which IL-6 may facilitate disease progression are not fully known. Here, in cell and tumor sphere models, cancer initiation and lung cancer stem cell (CSC) proliferation were enhanced by upregulation of DNA methyltransferase 1 (DNMT1) as a consequence of IL-6/JAK2/STAT3 pathway activity. DNMT1 upregulation resulted in DNA hypermethylation and downregulation of p53 and p21. Upon blockage of the IL-6/JAK2/STAT3 pathway and inhibition of DNMT1, the proliferation of lung CSCs, their formation of spheres, and their ability to initiate tumor growth decreased.