新疆维族与汉族乳腺癌组织mTOR及其下游分子4EBPl和S6K1表达差异研究

目的：探讨新疆维吾尔族和汉族乳腺癌组织中哺乳动物雷帕霉素靶蛋白（mammalian target of rapamycin,mTOR）及其下游分子4EBPl和S6K1的表达差异。方法：选取2005—0301—2009—09—30新疆医科大学附属肿瘤医院的维吾尔族和汉族女性浸润性乳腺癌患者285例,使用免疫组化方法检测磷酸化mTOR及其下游分子4EBPl和S6K1的表达状况;分别选取2012—01—01—20120630新疆医科大学附属肿瘤医院63例维、汉新鲜乳腺癌和癌旁组织样本,使用荧光定量RT-PCR法检测mTOR及其下游分子4EBPl和S6K1的mRNA表达状况。结果：免疫组化结果显示,维吾尔族和汉族p-mTOR在乳腺癌组织中的阳性表达率分别为77．1％和67．4％（P=0．067）,在癌旁组织中的阳性表达率分别为57．6％和61．7％（P=0．485）;p-4EBPl在癌组织中的阳性表达率分别为31．9％和20．0％（P=0．020）,在乳腺癌旁组织中的阳性表达率分别是4．9％和12．1％（P=0．029）;p-S6K1在癌组织中的阳性表达率分别为41．0％和43．3％（P=0．695）,在乳腺癌旁组织中的阳性表达率分别为14．0％和22．7％,P=0．054;荧光定量RT—PCR结果显示,维、汉乳腺癌组织中mTORmRNA相对定量结果差异有统计学意义,p=0．045;4EBPl和S6K1mRNA相对定量结果差异无统计学意义,P值分别为0．128和0．404。结论lmTOR信号通路中p-4EBPl的表达水平存在维、汉民族的差异,为研究维、汉不同民族之间乳腺癌差异及个体化治疗提供了进一步研究方向。mTOR及其下游分子mRNA表达水平与磷酸化蛋白的表达并不完全一致,提示蛋白表达的调控位点可能位于转录后水平。     

Phosphorylated S6K1 is a possible marker for endocrine therapy resistance in hormone receptor-positive breast cancer

Cross-talk between the estrogen receptor and the mammalian target of rapamycin (mTOR) pathway is one of the mechanisms of endocrine therapy resistance, and the phosphorylated S6 kinase 1(p-S6K1) is known to be a marker of the mTOR pathway activation. The authors assessed the prognostic significance of p-S6K1 according to the hormone receptor (HR) status. The expression of p-S6K1 was evaluated in 304 breast cancer tissues, and the association between its expression and patient outcomes was investigated. Among 197 cases with the HR (+) tumor, 70 (35.5%) were positive for p-S6K1. Most of the patients (97.5%) with the HR (+) tumor received adjuvant endocrine therapy. The expression of p-S6K1 was found to be an independent worse prognosticator affecting overall survival (OS) and breast cancer-specific survival (BCSS) in the HR (+) group (hazard ratio, 2.62; 95% confidence interval [CI], 1.19–5.76; P = 0.017 and hazard ratio, 3.25; 95% CI, 1.20–8.82; P = 0.020, respectively). In the HR (−) group, however, the p-S6K1 expression was not associated with patients’ survival. The expression of p-S6K1 is a worse prognostic factor in patients with HR (+) tumors. These results suggest that the p-S6K1 expression might be a marker for endocrine therapy resistance in patients with HR (+) tumors.     

Upregulated long non-coding RNA AFAP1-AS1 expression is associated with progression and poor prognosis of nasopharyngeal carcinoma

Altered expression of long noncoding RNAs (lncRNAs) associated with human carcinogenesis. We performed a cDNA microarray analysis of lncRNA expression in 12 cases of nasopharyngeal carcinoma (NPC) and 4 non-tumor nasopharyngeal epitheliums. One lncRNA, actin filament associated protein 1 antisense RNA1 (AFAP1-AS1), was identified and selected for further study. AFAP1-AS1 expression was upregulated in NPC and associated with NPC metastasis and poor prognosis. In vitro experiments demonstrated that AFAP1-AS1 knockdown significantly inhibited the NPC cell migration and invasive capability. AFAP1-AS1 knockdown also increased AFAP1 protein expression. Proteomic and bioinformatics analyses suggested that AFAP1-AS1 affected the expression of several small GTPase family members and molecules in the actin cytokeratin signaling pathway. AFAP1-AS1 promoted cancer cell metastasis via regulation of actin filament integrity. AFAP1-AS1 might be a potential novel marker that can predict cancer patient prognosis and as a potential therapeutic target for NPC.     

Phosphorylated 4E binding protein 1: a hallmark of cell signaling that correlates with survival in ovarian cancer

BACKGROUND: Growth factor receptors and cell signaling factors play a crucial role in human carcinomas and have been studied in ovarian tumors with varying results. Cell signaling involves multiple pathways and a myriad of factors that can be mutated or amplified. Cell signaling is driven through the mammalian target of rapamycin (mTOR) and extracellular regulated kinase (ERK) pathways and by some downstream molecules, such as 4E binding protein 1 (4EBP1), eukaryotic initiation factor 4E, and p70 ribosomal protein S6 kinase (p70S6K). The objectives of this study were to analyze the real role that these pathways play in ovarian cancer, to correlate them with clinicopathologic characteristics, and to identify the factors that transmit individual proliferation signals and are associated with pathologic grade and prognosis, regardless specific oncogenic alterations upstream. METHODS: One hundred twenty-nine ovarian epithelial tumors were studied, including 20 serous cystadenomas, 7 mucinous cystadenomas, 11 serous borderline tumors, 16 mucinous borderline tumors, 29 serous carcinomas, 16 endometrioid carcinomas, 15 clear cell carcinomas, and 15 mucinous carcinomas. Tissue microarrays were constructed, and immunohistochemistry for the receptors epidermal growth factor receptor (EGFR) and c-erb-B2 was performed and with phosphorylated antibodies for protein kinase B (AKT), 4EBP1, p70S6K, S6, and ERK. RESULTS: Among 129 ovarian neoplasms, 17.8% were positive for c-erb-B2, 9.3% were positive for EGFR, 47.3% were positive for phosphorylated AKT (p-AKT), 58.9% were positive for p-ERK, 41.1% were positive for p-4EBP1, 26.4% were positive for p70S6K, and 15.5% were positive for p-S6. Although EGFR, p-AKT, and p-ERK expression did not differ between benign, borderline, or malignant tumors, c-erb-B2, p-4EBP1, p-p70S6K, and p-S6 were expressed significantly more often in malignant tumors. Only p-4EBP1 expression demonstrated prognostic significance (P = .005), and only surgical stage and p-4EBP1 expression had statistical significance in the multivariate analysis. CONCLUSIONS: In patients with ovarian carcinoma, significant expression of p-4EBP1 was associated with high-grade tumors and a poor prognosis, regardless other oncogenic alterations upstream. This finding supports the study of this factor as a hallmark or pivotal factor in cell signaling in ovarian carcinoma that may crucial in the transmission of the proliferation cell signal and may reflect the real oncogenic role of this pathway in ovarian tumors.     

MicroRNA-150对上皮性卵巢癌细胞增殖、凋亡和侵袭转移能力的影响

目的 研究microRNA-150(miR-150)在人上皮性卵巢癌细胞中的表达情况,及其对人上皮性卵巢癌细胞增殖、凋亡和侵袭转移能力的影响。方法 通过荧光实时定量PCR(qRT-PCR)检测各处理组细胞中的miR-150表达水平;利用MTT法、流式细胞技术、Transwell法探究miR-150的表达对上皮性卵巢癌细胞增殖、凋亡及侵袭转移能力的影响。结果 与正常卵巢上皮细胞(T29)相比,上皮性卵巢癌细胞(A2780和OVCAR3)中miR-150表达显著降低(P＜0.01);转染miR-150mimic后,A2780和OVCAR3细胞中miR-150水平明显升高(P＜0.01);MTT试验显示,转染培养三天后,miR-150 mimic组细胞OD值(A2780:1.12±0.03;OVCAR3:1.91±0.03)较Blank组(A2780:2.35±0.09;OVCAR3:2.63±0.07)及miR-150 NC组(A2780:2.18±0.07;OVCAR3:2.43±0.11)明显降低(P＜0.01);细胞凋亡检测显示:miR-150 mimic组凋亡率(A2780:16.10±0.58%;OVCAR3:15.16±1.30%)较Blank组(A2780:10.07±0.66%;OVCAR3:3.81±0.24%)及miR-150 NC组(A2780:10.36±1.08%;OVCAR3:4.89±0.07%)明显升高(P＜0.01);Transwell试验显示:miR-150 mimic组穿膜细胞数(A2780:38.67±2.03;OVCAR3:28.67±2.03)较Blank组(A2780:76.30±7.45;OVCAR3:55.67±3.18)及miR-150 NC组(A2780:74.33±5.78;OVCAR3:56.33±3.84)明显减少(P＜0.01)。结论 miR-150在上皮性卵巢癌细胞中表达降低,可能是上皮性卵巢癌增殖、侵袭转移的机制之一;上调miR-150的表达可以抑制上皮性卵巢癌细胞增殖、促进细胞凋亡,并且降低上皮性卵巢癌细胞侵袭转移能力。     

PTEN promoter methylation and activation of the PI3K/Akt/mTOR pathway in pediatric gliomas and influence on clinical outcome

The signaling pathways that underlie the pathogenesis of pediatric gliomas are poorly understood. We characterized the PI3K/Akt/mTOR pathway in pediatric gliomas of all grades. Using immunohistochemistry, we assessed activation of the PI3K/Akt/mTOR pathway by evaluating the downstream signaling molecules phospho(p)-S6, phospho(p)-4BP1, and phospho(p)-PRAS40; PTEN; and PTEN promoter methylation, as well as the MIB labeling index. We correlated these findings with the clinical outcomes of 48 children with gliomas. Eighty percent of high-grade gliomas (12/15) showed activation of the PI3K/Akt/mTOR pathway based on p-S6 and p-4EBP1 expression. The majority of high-grade gliomas were negative for PTEN expression (10/15), and 50% had PTEN promoter methylation (grade III: 2/4; grade IV: 3/6). Low-grade gliomas demonstrated PI3K/Akt/mTOR pathway activation in 14/32 (43.8%) by p-S6 and 16/32 (50%) by p-4EBP1. Over 50% of grade I (6/11) and almost all grade II tumors (6/7) showed PTEN promoter methylation. Tumor grade correlated negatively with PTEN expression and positively with expression of p-S6 and p-4EBP1 (PTEN: P = .0025; pS6: P = .0075; p-4EBP1: P = .0066). There was a trend toward inverse correlation of methylation of the PTEN promoter with expression of PTEN protein (P= .0990) and direct correlation of expression of p-S6 and p-4EBP1 with poorer clinical outcome, as measured by progression-free survival (p-S6: P= .0874; p-4EBP1: P= .0475). Tumors with no PTEN expression had a higher MIB labeling index (P= .007). The majority of pediatric gliomas show activation of the PI3K/Akt/mTOR pathway, with methylation of the PTEN promoter occurring commonly in these tumors.     

EVI1 splice variants modulate functional responses in ovarian cancer cells

Amplification of 3q26.2, found in many cancer lineages, is a frequent and early event in ovarian cancer. We previously defined the most frequent region of copy number increase at 3q26.2 to EVI1 (ecotropic viral integration site-1) and MDS1 (myelodysplastic syndrome 1) (aka MECOM), an observation recently confirmed by the cancer genome atlas (TCGA). MECOM is increased at the DNA, RNA, and protein level and likely contributes to patient outcome. Herein, we report that EVI1 is aberrantly spliced, generating multiple variants including a Del^190–515 variant (equivalent to previously reported) expressed in >90% of advanced stage serous epithelial ovarian cancers. Although EVI1^Del190–515 lacks ～70% of exon 7, it binds CtBP1 as well as SMAD3, important mediators of TGFβ signaling, similar to wild type EVI1. This contrasts with EVI1 1–268 which failed to interact with CtBP1. Interestingly, the EVI1^Del190–515 splice variant preferentially localizes to PML nuclear bodies compared to wild type and EVI1^Del427–515. While wild type EVI1 efficiently repressed TGFβ-mediated AP-1 (activator protein-1) and plasminogen activator inhibitor-1 (PAI-1) promoters, EVI1^Del190–515 elicited a slight increase in both promoter activities. Expression of EVI1 and EVI1^Del427–515 (but not EVI1^Del190–515) in OVCAR8 ovarian cancer cells increased cyclin E1 LMW expression and cell cycle progression. Furthermore, knockdown of specific EVI1 splice variants (both MDS1/EVI1 and EVI1^Del190–515) markedly increased claudin-1 mRNA and protein expression in HEY ovarian and MDA-MB-231 breast cancer cells. Changes in claudin-1 were associated with alterations in specific epithelial–mesenchymal transition markers concurrent with reduced migratory potential. Collectively, EVI1 is frequently aberrantly spliced in ovarian cancer with specific forms eliciting altered functions which could potentially contribute to ovarian cancer pathophysiology.     

乳腺癌转移抑制基因1对卵巢癌细胞血管生成的影响及其机制探讨

目的探讨乳腺癌转移抑制基因1(breast cancer metastasis suppressor 1,BRMS1)对人卵巢癌细胞OVCAR3诱导血管内皮细胞形成管腔能力的影响及可能的机制。方法应用脂质体介导的方法将BRMS1 shRNA重组质粒转染人卵巢癌细胞OVCAR3,经G418筛选获得稳定转染株。荧光定量PCR和Western blot法检测BRMS1 mRNA和蛋白的表达水平;体外血管形成实验检测OVCAR3诱导人脐静脉内皮细胞(HUVECs)的血管形成能力;Western blot法检测生长抑制因子4(ING4)和白细胞介素-6(IL-6)的蛋白表达情况。结果稳定转染BRMS1 shRNA后,OVCAR3细胞BRMS1的表达在 mRNA和蛋白水平均受到明显抑制。体外血管形成实验提示,BRMS1表达下调后能显著促进卵巢癌细胞诱导的HUVECs形成管腔样结构的能力;Western blot法显示干扰组中ING4蛋白表达量较对照组下降30%,而IL-6蛋白表达上调,是空白对照组的1.5倍,差异有统计学意义(P<0.05)。结论干扰BRMS1基因的表达可促进卵巢癌细胞诱导血管形成能力,其机制可能与调节下游基因ING4和IL-6的表达有关。     

Plumbagin inhibits tumorigenesis and angiogenesis of ovarian cancer cells in vivo

Angiogenesis is a hallmark of tumor development and metastatic progression, and anti‐angiogenic drugs targeting the VEGF pathway have shown to decrease the disease progression in cancer patients. In this study, we have analyzed the anti‐proliferative and anti‐angiogenic property of plumbagin in cisplatin sensitive, BRCA2 deficient, PEO‐1 and cisplatin resistant, BRCA2 proficient PEO‐4 ovarian cancer cells. Both PEO‐1 and PEO‐4 ovarian cancer cells are sensitive to plumbagin irrespective of BRCA2 status in both normoxia and hypoxia. Importantly, plumbagin treatment effectively inhibits VEGF‐A and Glut‐1 in PEO‐1 and PEO‐4 ovarian cancer cells. We have also analyzed the p53 mutant, cisplatin resistant, and BRCA2 proficient OVCAR‐5 cells. Plumbagin challenge also restricts the VEGF induced pro‐angiogenic signaling in HUVECs and subsequently endothelial cell proliferation. In addition, we observe a significant effect on tumor regression among OVCAR‐5 tumor‐bearing mice treated with plumbagin, which is associated with significant inhibition of Ki67 and vWF expressions. Plumbagin also significantly reduces CD31 expression in an ear angiogenesis assay. Collectively, our studies indicate that plumbagin, as an anti‐cancer agent disrupts growth of ovarian cancer cells through the inhibition of proliferation as well as angiogenesis.     

BRMS1shRNA表达载体的构建及对卵巢癌细胞转移的影响

目的 探讨乳腺癌转移抑制基因1( BRMS1)表达抑制对人卵巢癌细胞转移能力的影响及机制.方法 构建靶向BRMS1基因的短发夹状RNA(shRNA)真核表达载体pGPU6/GFP/Neo-BRMS1,并转染人卵巢癌OVCAR3细胞,经G418筛选获得稳定转染株.采用实时荧光定量PCR和Western blot法分别检测...     

Up-regulation of C1GALT1 promotes breast cancer cell growth through MUC1-C signaling pathway

Aberrant glycosylation is frequently observed in cancers. Core 1 β1,3-galactosyltransferase (C1GALT1) is an exclusive enzyme in humans that catalyzes the biosynthesis of core 1 O-glycan structure, Gal-GalNAc-O-Ser/Thr, whose expression is commonly up-regulated during tumorigenesis. Little is known about the function of C1GALT1 in breast cancer. This study aims to determine the correlation between C1GALT1 expression and breast cancer clinicopathological features and roles of C1GALT1 in breast cancer malignant phenotypes. Public databases and our data showed that C1GALT1 mRNA and C1GALT1 protein are frequently up-regulated in breast cancer; and increased C1GALT1 expression correlates with higher histological grade and advanced tumor stage. Overexpression of C1GALT1 enhanced breast cancer cell growth, migration, and invasion in vitro as well as tumor growth in vivo. Conversely, C1GALT1 knockdown suppressed these malignant phenotypes. Furthermore, C1GALT1 modulates O-glycan structures on Mucin (MUC) 1 and promotes MUC1-C/β-catenin signaling in breast cancer cells. These findings suggest that C1GALT1 enhances breast cancer malignant progression through promoting MUC1-C/β-catenin signaling pathway. Unveiling the function of C1GALT1 in breast cancer opens new insights to the roles of C1GALT1 and O-glycosylation in tumorigenesis and renders the potential of C1GALT1 as a target of novel therapeutic agent development.     

Enhanced cisplatin cytotoxicity by disturbing the nucleotide excision repair pathway in ovarian cancer cell lines

Ovarian cancer is the leading cause of death among women from gynecological malignancies inthe United States. Resistance to the chemotherapeutic agent cisplatin isa major limitation for the successful treatment of ovarian cancer. In an effort to overcome the cisplatin resistance problem in ovarian cancer treatment, we have sought to enhance cisplatin cytotoxicity by perturbing the nucleotide excision repair (NER) pathway. The NER pathway is responsible for repairing cisplatin bound to DNA. Expression of one of the NER components, ERCC1, is correlated with cisplatin drug resistance. Hence, we targeted ERCC1 by antisense RNA methodologies, and we show that we could sensitize a relatively sensitive A2780 cell line and also the highly resistant OVCAR10 cell line to cisplatin by expressing antisense ERCC1 RNA in them as measured with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. The A2780 cell lines expressing antisense ERCC1 had 1.9-8.1-fold enhancements in cisplatin sensitivity. The OVCAR10 antisense ERCC1 cell lines had IC(50) values ranging from 2.28 microM to 2.7 microM cisplatin as compared with 9.52 micro M for control OVCAR10 cells. The OVCAR10 antisense ERCC1 cells also show reduced DNA-damage repair capacity as assessed by host cell reactivation. Furthermore, immunocompromised mice transplanted with the antisense cell lines survived longer than the mice bearing control cells after response to cisplatin treatment. These data suggest that it is possible to substantially enhance the cisplatin cytotoxicity by disturbing the NER pathway in cisplatin-resistant cell lines and to enhance the survival capacity of mice in an ovarian cancer xenograft model.     

Activation of the mTOR signaling pathway in breast cancer and its correlation with the clinicopathologic variables

AIMS: Rapamycin and its analogues are currently being tested in clinical trials as novel-targeted anticancer agents. Pre-clinical studies that used breast cancer cell lines have suggested that p-Akt or p-S6K1 expressing tumors, as well as PTEN negative tumors, were sensitive to rapamycin. The aims of this study were to determine the proportion of breast cancer that could be candidates for rapamycin treatment and to elucidate the clinicopathologic characteristics and prognosis of potentially rapamycin-sensitive tumors. METHODS: We evaluated the expressions of PTEN, p-Akt and p-S6K1 by performing immunohistochemistry in 122 breast cancer tissues. We analyzed the association of the expression of these proteins with the cliniopathologic variables and the disease-free survival. RESULTS: PTEN negative tumors, p-Akt expressing tumors and p-S6K1 expressing tumors constituted 4.1% (5/122), 41.0% (50/122), and 36.1% (44/122) of the total tumors, respectively. The proportion of tumors that met the criteria of rapamycin sensitivity was 54.9% (67/122). We could not find any significant correlation between the expression of these proteins and the other prognostic factors. However, the prognosis of tumors with a p-S6K1 expression was significantly worse than that of the p-S6K1 negative tumors. CONCLUSION: Based on the status of the PTEN, p-Akt and p-S6K1 expressions as predictors of rapamycin sensitivity, this study suggested that over 50% of breast cancer patients could be potential candidates for rapamycin treatment. In addition, the p-S6K1 expression may constitute an independent prognostic factor for disease-free survival.     

The Notch pathway in ovarian carcinomas and adenomas

Elements of the Notch pathway regulate differentiation; we investigated the expression of such elements in epithelial ovarian tumours. A total of 32 ovarian tumour samples (17 adenocarcinomas, three borderline tumours, 12 adenomas), two human ovarian cancer (A2780, OVCAR3), and one ovarian surface (IOSE 144) cell lines were analysed. The expression of Notch pathway elements was assessed by RT-PCR, real-time PCR (Notch 1), and by immunoblots (Notch 1 extracellular domain (EC), HES1). The proliferation and colony formation of A2780 cells were measured after stable transfection with activated Notch 1 (intracellular domain). Jagged 2, Delta-like-1, Manic Fringe, and TSL1 were expressed more frequently in adenocarcinomas whereas Deltex, Mastermind, and Radical Fringe were more frequent in adenomas. Quantitative PCR revealed decreased Notch 1 mRNA in ovarian adenocarcinomas compared with adenomas. The expression of Notch 1-EC protein was similar in benign and malignant tumours. HES1 protein was strongly expressed in 18/19 ovarian cancers and borderline tumours but not in adenomas. Transfecting A2780 cells with active Notch 1-IC resulted in a proliferative and colony formation advantage compared to mock transfected cells. Thus, Notch pathway elements are expressed in ovarian epithelial tumours and some of them are differentially expressed between adenomas and carcinomas. The Notch pathway could be a target for the development of therapies for ovarian cancer.