ZNF488对电离辐射诱发的鼻咽癌细胞CNE1侵袭迁移能力的影响

[目的]研究ZNF488 siRNA对电离辐射诱发的鼻咽癌CNE1侵袭迁移能力的影响.[方法]采用qRT-PCR和Western blot检测ZNF488 siRNA转染效率.采用划痕实验和Transwell侵袭实验检测电离辐射对鼻咽癌CNE1细胞侵袭迁移能力的影响.采用划痕实验和Transwell侵袭实验检测沉默ZNF488后,电离辐射诱发的CNE1细胞侵袭迁移能力是否改变.[结果]在mRNA和蛋白水平,实验组(siZNF488组)表达量均明显低于对照组(siRNA-Ctrl 组),其中实验组ZNF488 mRNA水平为对照组的(0.54±0.12)倍(P=0.023).划痕实验证明电离辐射明显增强鼻咽癌CNE1细胞迁移能力;Traoswell侵袭实验检测到0Gy组侵袭细胞数为302.67± 18.77,4Gy组侵袭细胞数为371.67± 15.63,4Gy组侵袭细胞数为0Gy组(1.23±0.03)倍(P=0.006).沉默ZNF488后,电离辐射诱发的CNE1细胞侵袭迁移能力明显减弱,这一功能的实现与上皮间质转化(EMT)进程的逆转息息相关.[结论]ZNF488 siRNA通过逆转EMT进程抑制鼻咽癌细胞CNE1电离辐射诱发的侵袭迁移能力.     

Dynamic equilibrium between cancer stem cells and non-stem cancer cells in human SW620 and MCF-7 cancer cell populations

Background:

Cancer stem cells (CSCs) paradigm suggests that CSCs might have important clinical implications in cancer therapy. Previously, we reported that accumulation efficiency of CSCs is different post low- and high-LET irradiation in 48 h.

Methods:

Cancer stem cells and non-stem cancer cells (NSCCs) were sorted and functionally identified through a variety of assays such as antigen profiles and sphere formation. Inter-conversion between CSCs and NSCCs were in situ visualised. Cancer stem cells proportions were assayed over multiple generations under normal and irradiation surroundings. Supplement and inhibition of TGF-β1, as well as immunofluorescence assay of E-cadherin and Vimentin, were performed.

Results:

Surface antigen markers of CSCs and NSCCs exist in an intrinsic homoeostasis state with spontaneous and in situ visualisable inter-conversions, irrespective of prior radiations. Supplement with TGF-β1 accelerates the equilibrium, whereas inhibition of TGF-β signalling disturbs the equilibrium and significantly decreases CSC proportion. Epithelial mesenchymal transition (EMT) might be activated during the process.

Conclusion:

Our results indicate that the intrinsic inter-conversion and dynamic equilibrium between CSCs and NSCCs exist under normal and irradiation surroundings, and TGF-β might have important roles in the equilibrium through activating EMT.     

脂肪间充质干细胞分泌的Exosome促进结肠癌细胞系上皮间质转化

目的：研究间充质干细胞（mesenchymal stem cell,MSC）来源的Exosome对结肠癌细胞系HCT8上皮间质转化（epithelial mesenchymal transition,EMT）的影响。方法从人脂肪组织中分离出MSC后,对MSC进行培养并传代,并对MSC的分化能力进行鉴定。在人脂肪来源的MSC中提取Exosome后,用透射电子显微镜观察并拍照,并用蛋白质印迹法检测其抗原表达情况。在HCT8培养体系中加入人脂肪来源的MSC分泌的Exosome ,定量PCR和蛋白质印迹法检测上皮和间质转化相关标志物的表达,细胞侵袭和迁移实验检测人脂肪来源的MSC分泌的Exosome对HCT8迁移和侵袭的影响。结果人脂肪来源的MSC具有多系分化能力,人脂肪来源的Exosome直径为40～100 nm ,表达CD63、HSP70和HSP90,下调HCT8上皮相关标志E-cadherin和ZO-1的表达,上调间质相关标志Fibronectin的表达,促进HCT8的迁移和侵袭。结论人脂肪来源的MSC分泌的Exosome可促进结肠癌细胞系HCT8的EMT。     

缺氧微环境下HIF-1α对胰腺癌细胞上皮间质转化及侵袭迁移的影响

目的:探讨缺氧微环境下缺氧诱导因子-1α（hypoxia inducible factor-1α,HIF-1α）对胰腺癌细胞上皮间质转化（epithelial-mesenchymal transition,EMT）及侵袭迁移的影响。方法:首先比较缺氧和常氧培养的胰腺癌细胞形态和体外侵袭迁移能力,以及HIF-1α和EMT相关因子的表达水平。然后通过HIF-1α抑制剂YC-1和siRNA基因沉默分别从蛋白和mRNA水平抑制HIF-1α的表达,检测缺氧培养的胰腺癌细胞体外侵袭迁移能力,以及EMT相关基因的表达水平。结果:形态学和分子水平证实缺氧诱导人胰腺癌细胞株AsPC-1、Capan-2、Panc-1的EMT改变,增强其体外侵袭和迁移能力。缺氧上调HIF-1α、Snail、N-cadherin的表达,下调E-cadherin的表达。抑制HIF-1α的表达后,Snail和N-cadherin表达下调,E-cadherin表达上调,并且体外侵袭迁移能力降低。结论:HIF-1α介导EMT在缺氧促进胰腺癌细胞侵袭迁移中发挥重要作用。     

Relationship between epithelial to mesenchymal transition and chemoresistance of lung cancer

Objective： The aim of this study was to explore the correlation between epithelial to mesenchymal transition （EMT） and chemoresistance of non-small-cell lung cancer （NSCLC）. Methods： In vitro, the drug resistance index of cisplatin resistant lung adenocarcinoma cell line （A549/DDP） was detected by CCK-8 assay; the morphological change between A549/ DDP cells and lung adenocarcinoma cells （A549） was observed by phase contrast microscope; expression of EMT markers （including E-cadherin and vimentin） and resistance protein, excision repair cross-complementing 1 （ERCC1） was detected by immunocytochemistry. The expression of E-cadherin, vimentin and ERCC1 was investigated by immunohistochemistry in 120 cases of NSCLC, half of that were treated with pre-operative neoadjuvant chemotherapy （neoadjuvant chemotherapy group）, and the other underwent surgery alone （simple surgery group）. Results： There was a significant difference between the ICso （half maximal inhibitory concentration） of A549/DDP cells （5.20） and A549 cells （1.88） （P 〈 0.05）, and the drug resistance index of A549/DDP cells was 2.77. Compared with A549 cells, A549/DDP cells increased expression of ERCC1 （P 〈 0.05）. Moreover, A549/DDP cells showed morphological and phenotypic changes consistent with EMT： with spindle-shaped morphology, and decreased expression of E-cadherin and increased expression of vimentin. Immunohistochemistry showed significant positive correlation between the expression of ERCCI and vimentin （r = 0.496, 0.332, P 〈 0.05）, and significant negative correlation between the ERCCI and E-cadherin （r = -0.403, -0.295, P 〈 0.05） in neoadjuvant chemotherapy group and simple surgery group. In addition, compared with simple surgery group, the expression of ERCC1 （P = 0.003） and vimentin （P = 0.004） was significantly increased, and the expression of E-cadherin was decreased in neoadjuvant chemotherapy group （P = 0.032）. Cenclusion： A549/DDP cells acquired cisplatin-resistance and occurred EMT simultaneously; the phenomenon of chemoresistance and EMT was caused more easily in neoadjuvant chemotherapy group. As such, we further confirmed the close correlation between chemoresistance and EMT of NSCLC, and provided theoretical basis for the targeting therapy with EMT regulatory factor for chemoresistant NSCLC patients.     

Exposure to febrile-range hyperthermia potentiates Wnt signalling and epithelial–mesenchymal transition gene expression in lung epithelium

Background: As environmental and body temperatures vary, lung epithelial cells experience temperatures significantly different from normal core temperature. Our previous studies in human lung epithelium showed that: (i) heat shock accelerates wound healing and activates profibrotic gene expression through heat shock factor-1 (HSF1); (ii) HSF1 is activated at febrile temperatures (38–41?°C) and (iii) hypothermia (32?°C) activates and hyperthermia (39.5?°C) reduces expression of a subset of miRNAs that target protein kinase-Cα (PKCα) and enhance proliferation.

Methods: We analysed the effect of hypo- and hyperthermia exposure on Wnt signalling by exposing human small airway epithelial cells (SAECs) and HEK293T cells to 32, 37 or 39.5?°C for 24?h, then analysing Wnt-3a-induced epithelial–mesenchymal transition (EMT) gene expression by qRT-PCR and TOPFlash reporter plasmid activity. Effects of miRNA mimics and inhibitors and the HSF1 inhibitor, KNK437, were evaluated.

Results: Exposure to 39.5?°C for 24?h increased subsequent Wnt-3a-induced EMT gene expression in SAECs and Wnt-3a-induced TOPFlash activity in HEK293T cells. Increased Wnt responsiveness was associated with HSF1 activation and blocked by KNK437. Overexpressing temperature-responsive miRNA mimics reduced Wnt responsiveness in 39.5?°C-exposed HEK293T cells, but inhibitors of the same miRNAs failed to restore Wnt responsiveness in 32?°C-exposed HEK293T cells.

Conclusions: Wnt responsiveness, including expression of genes associated with EMT, increases after exposure to febrile-range temperature through an HSF1-dependent mechanism that is independent of previously identified temperature-dependent miRNAs. This process may be relevant to febrile fibrosing lung diseases, including the fibroproliferative phase of acute respiratory distress syndrome (ARDS) and exacerbations of idiopathic pulmonary fibrosis (IPF).     

Expression and function role of DNA methyltransferase 1 in human bladder cancer

BACKGROUND:

The identification of potential tumor markers will help improve therapeutic planning and patient management. Therefore, the aim of this study was to highlight the role of DNA methyltransferase 1 (DNMT1) in bladder cancer.

METHODS:

A total of 50 samples of nonmalignant urothelium, 65 of muscle‐invasive bladder cancers, 15 of distant metastasis, and 50 of nonmuscle‐invasive bladder cancers were selected for immunohistochemical staining analysis. Furthermore, human bladder cancer cell lines HT1376 and HT1197 were selected for cell and animal experiments investigating changes in tumor behavior, treatment response, and related signaling in bladder cancer.

RESULTS:

The incidence of nuclear DNMT1 immunoreactivity in the bladder cancer specimens (45%) was significantly higher than in nonmalignant urothelium (15%, P = .0005), and the incidence in cancer was positively linked to clinical stage (24% in ≤T1 vs 55% in T2‐T4, P = .0007). The staining of DNMT1 was also significantly linked to lower complete response rates (P = .0014) and reduced survival rates (P = .000). By in vitro and in vivo experiments, DNMT1 silencing vector reduced tumor growth and attenuated treatment resistance in bladder cancer cells. Less epithelial‐mesenchymal transition, less invasion, and slower tumor growth were noted in cancer cells with inhibited DNMT1. Furthermore, the epidermal growth factor receptor‐mediated phosphatidylinositol 3′–kinase‐protein kinase B pathway might be the mechanism underlying the effects of DNMT1 on bladder cancer.

CONCLUSIONS:

DNMT1 could be a significant clinical predictor for stage and treatment response of bladder cancer. Moreover, targeting this enzyme could be a promising strategy for treating bladder cancer, as evidenced by inhibited tumor growth and enhanced radiosensitivity. Cancer 2011;. © 2011 American Cancer Society.     

TGF-β1诱导上皮间质转化过程中线粒体合成与功能的改变

目的：研究在转化生长因子-β1（TGF-β1）诱导上皮间质转化过程中线粒体合成与功能的改变。方法：体外培养人肺癌A549细胞,经不同浓度（0、2.5、5、10、20、40 ng/mL） TGF-β1处理24和48 h后观察其形态变化;采用CCK-8法检测经TGF-β1处理48 h后A549细胞的活力;流式细胞术检测细胞凋亡、活性氧（ROS）、线粒体活性氧及线粒体膜电位的变化;酶标仪检测ATP含量;Western blot分别检测细胞中上皮间质转化（EMT）相关标记物（E-cadherin和α-SMA）及线粒体合成相关蛋白（NRF-1及mt-TFA）的表达水平。结果：与对照组相比,随着TGF-β1浓度增加,A549细胞活力逐步上升,呈剂量-效应关系（r=0.941,P < 0.05）;5~20 ng/mL TGF-β1处理组凋亡率明显升高（P均 < 0.05）;不同浓度TGF-β1处理A549细胞48 h后大部分细胞呈现明显的间质细胞形态,出现上皮间质转化;Western blot结果显示,与对照组比较,经TGF-β1处理48 h后上皮标记物E-cadherin蛋白表达水平逐渐降低（P < 0.05）,间质标记物α-SMA表达水平逐渐升高（P < 0.05）;流式细胞术检测结果显示,5~20 ng/mL TGF-β1处理后细胞内ROS含量上升（P < 0.05）,线粒体活性氧上升（P < 0.05）,线粒体膜电位荧光强度下降（P < 0.05）,ATP含量降低（P < 0.05）,线粒体合成相关蛋白NRF-1和mt-TFA表达水平均下调（P均 < 0.05）。结论：TGF-β1诱导细胞发生上皮间质转化过程中线粒体的合成与功能受到影响,并由此促进了EMT的发生。     

Radiation promotes malignant phenotypes through SRC in breast cancer cells

Despite the fact that ionizing radiation (IR) is widely used as a standard treatment for breast cancer, much evidence suggests that IR paradoxically promotes cancer malignancy. However, the molecular mechanisms underlying radiation‐induced cancer progression remain obscure. Here, we report that irradiation activates SRC signaling among SRC family kinase proteins, thereby promoting malignant phenotypes such as invasiveness, expansion of the cancer stem‐like cell population, and resistance to anticancer agents in breast cancer cells. Importantly, radiation‐activated SRC induced SLUG expression and caused epithelial–mesenchymal cell transition through phosphatidylinositol 3‐kinase/protein kinase B and p38 MAPK signaling. In agreement, either inhibition of SRC or downstream signaling of p38 MAPK or protein kinase B effectively attenuated radiation‐induced epithelial–mesenchymal cell transition along with an increase in the cancer stem‐like cell population. In addition, downregulation of SRC also abolished radiation‐acquired resistance of breast cancer cells to anticancer agents such as cisplatin, etoposide, paclitaxel, and IR. Taken together, our findings suggest that combining radiotherapy with targeting of SRC might attenuate the harmful effects of radiation and enhance the efficacy of breast cancer treatment.