IL‐6 enriched lung cancer stem‐like cell population by inhibition of cell cycle regulators via DNMT1 upregulation

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.     

LncRNA TCF7调节JAK/STAT信号通路对肺癌细胞增殖的影响

目的探究长链非编码RNA(long non-coding RNA,LncRNA) TCF7调控JAK/STAT信号通路对肺癌细胞增殖的影响。方法收集22例肺癌患者肿瘤组织及癌旁正常组织,采用荧光实时定量聚合酶链式反应(Real-time Polymerase Chain Reaction, RT-PCR)检测标本中TCF7的mRNA表达,并分析预后及与临床指标之间的关系,通过查阅在线数据库及RT-PCR法检测TCF7在肺癌细胞株A549、H1688、H1299以及H1975细胞中亚细胞定位情况。此外,采用siRNA技术构建TCF7敲低模型(si-TCF7),RT-PCR验证转染效率后,采用Cell Counting Kit-8(CCK8)试剂盒检测A549细胞的增殖活性,Western Blot法检测JAK/STAT信号通路的蛋白表达。结果与癌旁正常组织相比,TCF7在肺癌组织中表达显著上调(P<0.05),Kaplan-Meier分析显示TCF7高表达预后更差(P=0.043)。与支气管上皮细胞株16HBE细胞相比,A549、H1688、H1299以及H1975细胞中TCF7的表达均显著上调,且A549细胞中TCF7的表达水平最高(P<0.05)。Locator数据库和PCR结果均显示,TCF7主要分布于A549细胞的细胞质中。TCF7的表达水平与肺癌患者的TNM分期有明显相关性(P<0.05),而与患者的性别、年龄以及肿瘤病理分型无关(P>0.05)。沉默TCF7后A549细胞中TCF7的表达显著下调(P<0.05),A549细胞的增殖能力被显著抑制(P<0.05),此外,低表达TCF7可显著抑制JAK/STAT3信号通路的磷酸化水平(P<0.05)。结论 LncRNA TCF7在肺癌组织和细胞中高表达,敲低TCF7通过抑制JAK/STAT通路的活化可抑制肺癌细胞的增殖能力。     

丙泊酚抑制IL-6诱导的A549肺癌细胞上皮间质转化及其机制探讨

目的:探究丙泊酚对白细胞介素-6（IL-6）诱导的A549肺癌细胞上皮间质转化（EMT）的作用及机制。方法:将A549细胞随机分成四组:对照组、IL-6组（50 ng/ml重组IL-6蛋白）、IL-6+丙泊酚低剂量组（50 ng/ml重组IL-6蛋白和5 μmol/L丙泊酚）、IL-6+丙泊酚高剂量组（50 ng/ml重组IL-6蛋白和10 μmol/L丙泊酚）。MTT法检测细胞活力，Transwell检测细胞迁移情况，Real-time PCR方法检测EMT相关基因（E-cadherin、Vimentin和Snail1）mRNA的表达水平，Western blot检测EMT相关蛋白及JAK2和STAT3的磷酸化表达水平。使用0.5 μmol/L STAT3激活剂colivelin处理细胞，检测其对丙泊酚调节的IL-6诱导的A549细胞活力、迁移和EMT的影响。结果:与对照组相比，IL-6组中细胞的活力、迁移、EMT和JAK2/STAT3的活化均增加（P均<0.05）；与IL-6组相比，IL-6+丙泊酚组中细胞活力、迁移、EMT和JAK2/STAT3的活化均降低（P均<0.05），这些变化均具有剂量依赖性。STAT3激活剂能够减弱丙泊酚对IL-6诱导的A549细胞活力、迁移和EMT的影响（P均<0.05）。结论:丙泊酚能够抑制IL-6诱导的A549肺癌细胞EMT进程，这种作用是通过抑制JAK2/STAT3的活化发挥作用的。     

碳离子（12C6+）抑制JAK2/STAT3通路促进肺癌中CD8+ T细胞浸润的研究

目的 探索碳离子（¹²C⁶⁺）照射后JAK2/STAT3通路的改变及下游蛋白FOXP3调控的肺癌中CD8⁺T细胞的浸润差异。方法 基于C57BL/6小鼠Lewis荷瘤模型的RNA测序分析,筛选出碳离子照射后肺癌中显著改变的JAK2/STAT3通路及相关的差异表达基因及蛋白如FOXP3。利用R软件“GSVA”中ssGSEA免疫浸润算法,探索FOXP3与肺癌免疫微环境中主要免疫细胞浸润的相关性并基于碳离子联合STAT3抑制途径（氯硝柳胺）对肺癌中CD8⁺T细胞浸润进行分析。结果 碳离子照射后,肺癌中JAK2/STAT3通路被抑制,相关基因和蛋白表达下调。基于ssGSEA算法的免疫评分显示,FOXP3表达与肺癌免疫微环境中CD8⁺T细胞浸润呈显著负相关。通过碳离子照射联合STAT3抑制剂氯硝柳胺,进一步明确了靶向JAK2/STAT3通路对于增加肺癌中CD8⁺T细胞浸润的协同作用。结论 碳离子（¹²C⁶⁺）可以通过靶向JAK2/STAT3通路与免疫治疗发挥协同增效的作用。     

碳离子(^(12)C^(6+))抑制JAK2/STAT3通路促进肺癌中CD8^(+)T细胞浸润的研究北大核心CSCD

目的探索碳离子(^(12)C^(6+))照射后JAK2/STAT3通路的改变及下游蛋白FOXP3调控的肺癌中CD8+T细胞的浸润差异。方法基于C57BL/6小鼠Lewis荷瘤模型的RNA测序分析,筛选出碳离子照射后肺癌中显著改变的JAK2/STAT3通路及相关的差异表达基因及蛋白如FOXP3。利用R软件“GSVA”中ssGSEA免疫浸润算法,探索FOXP3与肺癌免疫微环境中主要免疫细胞浸润的相关性并基于碳离子联合STAT3抑制途径(氯硝柳胺)对肺癌中CD8+T细胞浸润进行分析。结果碳离子照射后,肺癌中JAK2/STAT3通路被抑制,相关基因和蛋白表达下调。基于ssGSEA算法的免疫评分显示,FOXP3表达与肺癌免疫微环境中CD8+T细胞浸润呈显著负相关。通过碳离子照射联合STAT3抑制剂氯硝柳胺,进一步明确了靶向JAK2/STAT3通路对于增加肺癌中CD8^(+)T细胞浸润的协同作用。结论碳离子(^(12)C^(6+))可以通过靶向JAK2/STAT3通路与免疫治疗发挥协同增效的作用。     

Bone marrow-derived myofibroblasts promote colon tumorigenesis through the IL-6/JAK2/STAT3 pathway

Bone marrow-derived myofibroblasts (BMFs) have been shown to promote tumor growth. Here, we found that BMFs or BMF conditioned medium (BMF-CM) induced cancer stem cell-like sphere formation of colon cancer cells. The co-cultured BMFs, but not co-cultured cancer cells, expressed higher levels of IL-6 than BMFs or cancer cells cultured alone. Anti-mouse IL-6 neutralizing antibody, JAK2 inhibitors and STAT3 knockdown in mouse cancer cells reduced BMF- and BMF-CM-induced sphere formation of colon cancer cells. When co-injected, BMFs significantly enhanced tumorigenesis of colon cancer cells in mice. Our results demonstrate that BMFs promote tumorigenesis via the activation of the IL-6/JAK2/STAT3 pathway.     

Soy isoflavones radiosensitize lung cancer while mitigating normal tissue injury

Background

We have demonstrated that soy isoflavones radiosensitize cancer cells. Prostate cancer patients receiving radiotherapy (RT) and soy tablets had reduced radiation toxicity to surrounding organs. We have now investigated the combination of soy with RT in lung cancer (NSCLC), for which RT is limited by radiation-induced pneumonitis.

Methods

Human A549 NSCLC cells were injected i.v. in nude mice to generate lung tumor nodules. Lung tumor-bearing mice were treated with left lung RT at 12 Gy and with oral soy treatments at 1 mg/day for 30 days. Lung tissues were processed for histology.

Results

Compared to lung tumor nodules treated with soy isoflavones or radiation, lung tissues from mice treated with both modalities showed that soy isoflavones augmented radiation-induced destruction of A549 lung tumor nodules leading to small residual tumor nodules containing degenerating tumor cells with large vacuoles. Soy isoflavones decreased the hemorrhages, inflammation and fibrosis caused by radiation in lung tissue, suggesting protection of normal lung tissue.

Conclusions

Soy isoflavones augment destruction of A549 lung tumor nodules by radiation, and also mitigate vascular damage, inflammation and fibrosis caused by radiation injury to normal lung tissue. Soy could be used as a non-toxic complementary approach to improve RT in NSCLC.     

JAK2/STAT3信号通路对A549细胞株中HIF-1ɑ、VEGF蛋白表达的影响

目的：研究人肺腺癌细胞A549细胞中JAK2/STAT3信号通路对HIF-1ɑ、VEGF蛋白表达的影响。方法：AG490处理在氧含量正常及缺氧条件下（CoCl2200μmol/L）48h后Westernblot法测定A549细胞中HIF-1ɑ、VEGF蛋白表达变化（分组为对照组、AG49050μmol/L、AG490100μmol/L、CoCl2、CoCl2＋AG49050μmol/L和CoCl2＋AG490100μmol/L组）。IL-6（3.85nmol/L）处理A549细胞24h后,检测细胞中STAT3、p-STAT3、HIF-1ɑ、VEGF蛋白表达变化（分组为对照组,IL-6组）。结果：JAK2特异性抑制剂AG490作用48h后,相对于对照组AG490能够下调HIF-1ɑ、VEGF的蛋白表达,且呈浓度依赖性;随浓度的升高,抑制作用更明显。缺氧条件下（CoCl2200μmol/L）能够上调HIF-1ɑ、VEGF的蛋白表达。AG490也能够下调CoCl2诱导的HIF-1ɑ、VEGF的蛋白表达,且呈浓度依赖性,随浓度的升高,抑制作用更显著。IL-6能够上调HIF-1ɑ、VEGF的蛋白表达。结论：在人肺腺癌细胞A549细胞中,缺氧可上调HIF-1α和VEGF蛋白表达。JAK2/STAT3信号通路对HIF-1α和VEGF蛋白的表达具有调节作用。     

DNA damage induces the IL-6/STAT3 signaling pathway, which has anti-senescence and growth-promoting functions in human tumors

IL-6 is a multifunctional cytokine that is important for immune responses, cell survival, apoptosis, and proliferation. However, little is known about the correlation between the IL-6 signaling pathway and DNA damage in human tumors. The present study demonstrates the role of the IL-6/STAT3 signaling pathway in human tumor cells exposed to DNA damage. Tumor cells exposed to DNA damage increase the expression and secretion of IL-6 and the phosphorylation of JAK1 and STAT3. The activation of the JAK1-STAT3 signaling pathway is inhibited by knockdown of gp130 or neutralization of soluble IL-6, implying that DNA damage induces the phosphorylation of JAK1 and STAT3 by autocrine IL-6. Interestingly, inhibition of the IL-6/STAT3 signaling pathway impairs the growth of tumor cells exposed to DNA damage and results in the induction of senescence. Therefore, the present study suggests that IL-6 inhibits senescence but promotes the survival and proliferation of tumor cells exposed to DNA damage through the activation of the JAK1-STAT3 signaling pathway.     

Interaction between non-small-cell lung cancer cells and fibroblasts via enhancement of TGF-β signaling by IL-6

Introduction

Fibroblasts are key components of the tumor microenvironment. We clarified the role of transforming growth factor (TGF)-β and interleukin (IL)-6 in the interaction between fibroblasts and non-small-cell lung cancer (NSCLC) cells.

Methods

We used NSCLC cells (A549, NCI-H358) and normal human lung fibroblast (NHLF) cells to evaluate phenotypic changes in the presence of human IL-6, TGF-β1, and conditioned media (CM) from these cells. Possible pathways were evaluated with SB431542, a TGF-β receptor inhibitor, or an anti-human IL-6 receptor neutralizing antibody (IL-6R-Ab).

Results

A549 and NCI-H358 cells incubated with IL-6 (50 ng/mL) and TGF-β1 (2 ng/mL) showed significantly increased epithelial–mesenchymal transition (EMT) signaling compared to those treated with TGF-β1 alone. Furthermore, NHLF cells were synergistically activated by IL-6 and TGF-β1. IL-6 increased the expression of TGF-β type I receptors on the surface of A549, NCI-H358 and NHLF cells and enhanced TGF-β signaling. TGF-β1 induced phenotypic changes were attenuated by IL-6R-Ab. NHLF cells were activated and A549 cells showed induction of EMT in response to CM from the other cell type. These activities were attenuated by SB431542 or IL-6R-Ab, suggesting that interplay between NSCLC cells and NHLF may lead to increased EMT signaling in NSCLC cells and activation of NHLF cells through TGF-β and IL-6 signaling. Subcutaneous co-injection of A549 and NHLF cells into mice resulted in a high rate of tumor formation compared with injection of A549 cells without NHLF cells. SB431542 or IL-6R-Ab also attenuated the tumor formation enhanced by co-injection of the two cell types.

Conclusion

IL-6 enhanced epithelial cell EMT and stimulated tumor progression by enhancing TGF-β signaling. IL-6 and TGF-β may play a contributing role in maintenance of the paracrine loop between these two cytokines in the communication between fibroblasts and NSCLC cells for tumor progression.     

Acute myeloid leukemia (AML)-derived mesenchymal stem cells induce chemoresistance and epithelial–mesenchymal transition-like program in AML through IL-6/JAK2/STAT3 signaling

Acute myeloid leukemia (AML) has a high rate of treatment failure due to increased prevalence of therapy resistance. Mesenchymal stem cells (MSCs) in the leukemia microenvironment contribute to chemoresistance in AML, but the specific mechanism remains unclear. The critical role of the epithelial–mesenchymal transition (EMT)-like profile in AML chemoresistance has been gradually recognized. However, there is no research to suggest that the AML-derived bone marrow mesenchymal stem cells (AML-MSCs) induce the EMT program in AML thus far. We isolated AML-MSCs and cocultured them with AML cells. We found that AML-MSCs induced a significant mesenchymal-like morphology in drug-resistant AML cells, but it was scarce in parental AML cells. The AML-MSCs promoted growth of AML cells in the presence or absence of chemotherapeutics in vitro and in vivo. Acute myeloid leukemia MSCs also induced EMT marker expression in AML cells, especially in chemoresistant AML cells. Mechanistically, AML-MSCs secreted abundant interleukin-6 (IL-6) and upregulated IL-6 expression in AML cells. Acute myeloid leukemia cells upregulated IL-6 expression in AML-MSCs in turn. Meanwhile, AML-MSCs activated the JAK2/STAT3 pathway in AML cells. Two JAK/STAT pathway inhibitors counteracted the AML-MSCs induced morphology change and EMT marker expression in AML cells. In conclusion, AML-MSCs not only promote the emergence of chemoresistance but also enhance it once AML acquires chemoresistance. AML-MSCs induce EMT-like features in AML cells; this phenotypic change could be related to chemoresistance progression. AML-MSCs induce the EMT-like program in AML cells through IL-6/JAK2/STAT3 signaling, which provides a therapeutic target to reverse chemoresistance in AML.     

虫草素抑制JAK2/STAT3通路减轻肺癌大鼠放射性免疫功能损伤

目的 探讨虫草素通过JAK2/STAT3信号通路对肺癌大鼠放射性治疗免疫功能损伤的抑制作用。方法 50只大鼠建立荷瘤模型,另设正常组（10只）。建模成功大鼠随机分为模型组、放疗组、虫草素组、激动剂组和激动剂+虫草素组,每组10只。比较各组大鼠瘤重、肿瘤体积、抑瘤率、IL-6、TNF-α、脾指数、胸腺指数、T淋巴细胞亚群数量、JAK2、p-JAK2、STAT3和p-STAT3蛋白表达水平。结果 与正常组比较,模型组IL-6、TNF-α、CD8+、p-JAK2、p-STAT3升高,脾指数、胸腺指数、CD4+、CD4+/CD8+降低（P<0.05）;与模型组比较,放疗组瘤重、肿瘤体积、脾指数、胸腺指数、CD4+、CD4+/CD8+降低,IL-6、TNF-α、CD8+、p-JAK2和p-STAT3升高（P<0.05）;与放疗组比较,虫草素组瘤重、肿瘤体积、IL-6、TNF-α、CD8+、p-JAK2、p-STAT3降低,抑瘤率、脾指数、胸腺指数、CD4+、CD4+/CD8+升高,激动剂组瘤重、肿瘤体积、IL-6、TNF-α、CD8+、p-JAK2、p-STAT3升高,抑瘤率、脾指数、胸腺指数、CD4+、CD4+/CD8 +降低（P<0.05）;与激动剂+虫草素组比较,虫草素组瘤重、肿瘤体积、IL-6、TNF-α、CD8+、p-JAK2、p-STAT3降低,抑瘤率、脾指数、胸腺指数、CD4+、CD4+/CD8+升高,激动剂组瘤重、肿瘤体积、IL-6、TNF-α、CD8+、p-JAK2、p-STAT3升高,抑瘤率、脾指数、胸腺指数、CD4+、CD4+/CD8+降低（P<0.05）。结论 虫草素可有效抑制肺癌大鼠放射性治疗免疫功能损伤,其机制可能通过抑制JAK2/STAT3信号通路蛋白表达发挥调控作用。     

Unusual interleukin-4 and -13 signaling in human normal and tumor lung fibroblasts

IL-4 and IL-13 act on human lung fibroblasts through specific receptors differing in their composition. Indeed, the gammac chain is constitutively expressed in tumor lung myofibroblast but not in normal cells. Here, we have analysed the signal transduction induced by IL-4 and IL-13 in both cell types, in order to better understand the molecular mechanisms underlying tumor stromal development. The IL-4Ralpha chain is constitutively phosphorylated and pre-associated with the JAK1 protein in both cell types. In normal cells, we detected the activation of the classic IRS-2 or JAK1/STAT6 pathways, the phosphorylation of JAK2, while Tyk2 was constitutively phosphorylated and not modified by both cytokines. In addition to these pathways, in lung tumor myofibroblasts, IL-4 and IL-13 induced the phosphorylation of JAK3 and increased the phosphorylation of Tyk2. Interestingly, in both cell types IL-4 and IL-13 triggered an unusual pattern of STAT1 and STAT3 activation. These events probably correspond to a tissue-specific signaling important for the immunoregulatory functions of airways fibroblasts. Indeed, the inflammatory-like pattern of STATs signaling triggered by IL-4 and IL-13 in these cells may favor the homing of inflammatory and/or metastatic cells. In lung myofibroblasts, these properties could be modified through the different pattern of JAK activation.     

Apigenin affects leptin/leptin receptor pathway and induces cell apoptosis in lung adenocarcinoma cell line

Background

Apigenin, a common edible plant flavonoid, is a well characterised antioxidant. The adipokine leptin exerts proliferative and anti-apoptotic activities in a variety of cell types. In cancer cells, apigenin may induce a pro-apoptotic pathway whereas leptin has an anti-apoptotic role. The purpose of the study is to investigate the role of apigenin and of leptin/leptin receptor pathway on proliferation and on apoptosis in lung adenocarcinoma.

Methods

Immunocytochemistry, flow cytometry and RT-q-RT PCR, were used to investigate the expression and modulation of leptin receptors on the lung adenocarcinoma cell line A549 in presence or absence of apigenin and of leptin, alone or combined. Clonogenic test to evaluate cell proliferation was assessed. Exogenous leptin binding to its receptors by flow cytometry, reactive oxygen species (ROS) by dichlorofluorescein diacetate analysis, cell death by ethidium bromide and apoptosis by annexin V analysis were assessed. Apoptosis was assessed also in presence of lung adenocarcinoma pleural fluids (PF) (n = 6).

Results

A549 express leptin/leptin receptor pathway and its expression is upregulated by apigenin. Apigenin alone or combined with leptin significantly decreases cell proliferation and significantly increases the spontaneous release of ROS, with augmented cell death and apoptosis, this latter also in the presence of lung adenocarcinoma PF. Leptin alone significantly increases cell proliferation and significantly decreases cell death.

Conclusions

These results strongly suggest the potential utility of the flavonoid apigenin in the complementary therapeutic approach of patients with lung adenocarcinoma.     

苯丁酸调控对顺铂抑制人肺腺癌A549/DDP耐药细胞株增殖与侵袭协同作用研究

目的肺癌已成为威胁人类生存的重要杀手,且随着环境恶化,其发病率和死亡率有逐年升高趋势。本研究分析4-苯丁酸对顺铂作用下人肺腺癌耐药细胞株A549/DDP细胞增殖和侵袭影响,为临床治疗提供参考。方法体外培养人肺腺癌耐药细胞株A549/DDP至生长状态良好,分析顺铂及4-苯丁酸联合顺铂对A549/DDP细胞株增殖作用,酶联免疫吸附测定法分析细胞凋亡相关蛋白表达变化,Transwell实验分析细胞侵袭力变化,蛋白质印迹法和免疫细胞化学分析细胞中JAK/STAT信号通路蛋白表达变化。结果随着时间延长,各组对A549/DDP细胞株增殖抑制率呈上升趋势,且高剂量4-苯丁酸联合顺铂组对A549/DDP细胞株增殖抑制率较高,差异有统计学意义,F药物=110.342,P<0.001;F时间=34.527,P<0.001;F药物×时间=58.321,P<0.001。与对照组相比,低剂量4-苯丁酸联合顺铂组和高剂量4-苯丁酸联合顺铂组细胞凋亡蛋白Bcl-2水平降低,Bax、Caspase-3和Caspase-6水平升高,均P<0.001。对照组、顺铂组、低剂量4-苯丁酸联合顺铂组和高剂量4-苯丁酸联合顺铂组细胞侵袭力分别为423.3±35.6、389.3±24.7、375.6±35.2和285.6±23.9,F=44.458,P<0.001;蛋白质印迹法检测发现对照组、顺铂组、低剂量4-苯丁酸联合顺铂组和高剂量4-苯丁酸联合顺铂组JAK2水平分别为1.32±0.26、1.01±0.24、0.90±0.12和0.74±0.13,F=18.633,P<0.001;STAT2水平分别为0.78±0.13、0.70±0.15、0.62±0.09和0.54±0.09,F=18.996,P<0.001;STAT3水平分别为1.01±0.23、0.89±0.14、0.74±0.10和0.40±0.10,F=19.687,P<0.001。免疫细胞化学法检测发现对照组、顺铂组、低剂量4-苯丁酸联合顺铂组和高剂量4-苯丁酸联合顺铂组JAK2水平分别为0.85±0.14、0.78±0.11、0.62±0.17和0.52±0.09,F=21.854,P<0.001;STAT2水平分别为0.85±0.20、0.77±0.14、0.69±0.08和0.52±0.13,F=17.852,P<0.001;STAT3水平分别为0.63±0.14、0.57±0.11、0.50±0.09和0.42±0.08,F=29.754,P<0.001。结论4-苯丁酸调控对顺铂作用下人肺腺癌耐药细胞株A549/DDP细胞增殖、侵袭有明显抑制作用,且其作用可能与影响JAK/STAT信号通路蛋白表达有关。