miR-182靶向NUMB调控结直肠癌细胞增殖、迁移和侵袭的机制研究

目的:研究miR-182对结直肠癌细胞HT-29增殖、迁移和侵袭的影响,并探讨其机制。方法:运用qRT-PCR检测人正常结肠上皮细胞HCoEpiC、结直肠癌细胞HT-29中miR-182、NUMB的表达;将anti-miR-con组（转染anti-miR-con）、anti-miR-182组（转染anti-miR-182）、pcDNA组（转染pcDNA）、pcDNA-NUMB组（转染pcDNA-NUMB）、anti-miR-182+si-con组（anti-miR-182和si-con共转染）、anti-miR-182+si-NUMB组（anti-miR-182和si-NUMB共转染）均用脂质体法转染HT-29细胞;Western blot检测各组细胞中NUMB的蛋白表达;Transwell检测各组细胞的迁移和侵袭;MTT法检测各组细胞的增殖;双荧光素酶报告基因检测实验检测各组细胞的荧光素酶活性。结果:与人正常结肠上皮细胞HCoEpiC相比,结直肠癌细胞HT-29中miR-182表达显著升高,NUMB表达显著降低（P<0.05）;抑制miR-182、过表达NUMB均可下调HT-29细胞的增殖、迁移、侵袭;NUMB是miR-182的靶标。敲减NUMB可逆转抑制miR-182对HT-29细胞增殖、迁移、侵袭的下调作用。结论:miR-182可促进结直肠癌细胞的增殖、迁移、侵袭,其机制可能与靶向NUMB有关,将可为miR-182靶向治疗结直肠癌提供依据。     

Notch1和NUMB在胃癌组织中的表达水平及其意义

目的 研究Notchl和NUMB在胃癌组织中的表达情况及其与胃癌临床病理特征的关系.方法 采用Real-time PCR和Western blotting检测胃癌肿瘤组织和相应正常组织内Notch1和NUMB的表达.结果 Notchl mRNA在胃癌中的平均表达水平是正常胃组织的1.67倍(P<0.05),且与肿瘤的分...     

Characterization and role of NUMB in the human extravillous trophopblast

NUMB is a multifunctional protein involved in asymmetric cell differentiation, proliferation and maintenance. Four mammalian NUMB isoforms have been identified, which utilize the phosphotyrosine binding (PTB) domain and the proline rich region (PRR) domain to regulate cell growth and differentiation in the developing nervous system. The observation that a decrease in spongiotrophoblast number and thickness of placentae of null (Numb^−/−) mouse embryos, which died at E10.5, suggests NUMB may play a role in placental development. In this study, we demonstrated for the first time, that NUMB isoforms 1, 2, 3, and 4 are present in the human placenta and the human extravillous trophoblast (EVT) cell line HTR8/SVneo. We report three novel isoforms, NUMB 7, 8, and 9, identified by cloning of RT-PCR products and sequencing. Corresponding sequences of novel isoforms were submitted to genebank (accession numbers for each new isoform: NUMB 7- EU265736, NUMB 8- EU265737 and NUMB 9-EU265738). Western blot analysis confirmed the presence of all NUMB isofoms in human placental samples in all trimesters and in EVT cells. NUMB immunosignals were extensively localized in human extravillous trophoblasts and decidual cells at the maternal-fetal interface. NUMB 8 appeared to be the predominant isoform in placental villi. Furthermore, cell migration studies revealed NUMB isoform 1 to be involved in EVT cell migration and NUMB isoforms 2 and 4 to induce EVT apoptosis.     

The tumor suppressive role of NUMB isoform 1 in esophageal squamous cell carcinoma

Esophageal quamous cell carcinoma (ESCC) is the predominant histological type of esophageal carcinoma in Asian populations. To date, few biomarkers have been identified for ESCC. In present study, we found a tumor suppressor, NUMB isoform 1 (NUMB-1), as a promising prognostic biomarker for patients with ESCC. NUMB-1 mRNA was downregulated in 66.7% of primary ESCC tissues when compared with matched adjacent non-tumor tissues. The low expression of NUMB-1 was significantly associated with high tumor recurrence (p=0.029) and poor post-operative overall survival (p=0.016). To further explore the underlying mechanisms by which NUMB-1 regulates ESCC, we demonstrated that ectopic expression of NUMB-1 inhibited cell proliferation through inducing G2/M phase arrest, which was accompanied by an increase in p21 and cyclin B1-cdc2 levels. However, it had no impact on apoptosis of ESCC cells. In addition, overexpression of NUMB-1 prevented epithelial-mesenchymal transition, inhibited invasion of ESCC cells and NOTCH pathway, suppressed Aurora-A activity by preventing phosphorylation of Aurora-A at T288 which resulted in cell cycle arrest. Taken together, our findings suggested NUMB-1 functions as a tumor-suppressor and serves as a prognositc biomarker for ESCC patients; thus, NUMB-1 may be a potential novel therapeutic target for treatment of ESCC.     

Notchl和NUMB在胃癌组织中的表达水平及其意义

目的研究Notchl和NUMB在胃癌组织中的表达情况及其与胃癌临床病理特征的关系。方法采用Real—time PCR和Western blotting检测胃癌肿瘤组织和相应正常组织内Notchl和NUMB的表达。结果Notchl mRNA在胃癌中的平均表达水平是正常胃组织的1．67倍（P〈0．05）,且与肿瘤的分化程度和淋巴转移有关。NUMB mRNA在胃癌中的平均表达水平仅是正常胃组织的0．597倍（P〈0．05）,与肿瘤分化程度有关。Notchl和NUMB在胃癌组织中的表达呈负相关关系（r=-0．459,P〈0．05）。胃癌肿瘤组织中Notchl蛋白的相对含量为（0．348±0．133）,明显高于正常组织中Notchl蛋白的相对含量（0．208±0．140）（P〈0．05）,胃癌肿瘤组织中NUMB蛋白的相对含量为（0．490±0．440）,明显低于正常组织中NUMB蛋白的相对含量（0．746±0．390）（P〈0．05）。结论在胃癌中存在Notch信号转导通路的过度活化,Notchl的上调和NUMB的下调在胃癌发生、发展中可能发挥重要的作用。     

NUMB shRNA真核表达载体构建及对人U87胶质瘤细胞NUMB、p53表达的影响研究

目的：构建NUMB shRNA（短发夹RNA）真核表达载体,体外评价其对人U87胶质瘤细胞NUMB及p53 mRNA及P53蛋白表达的影响。方法：免疫荧光细胞化学染色证实NUMB、P53蛋白在U87胶质瘤细胞的表达。构建针对NUMB mRNA表达的一对反向shRNA互补序列,克隆入psilencer 3．1／hygro真核表达载体,在测序鉴定无误后将NUMB shRNA转染至U87胶质瘤细胞,用RT—PCR和Western blot检测U87细胞转染前后NUMB及p53基因和P53蛋白的表达水平变化。结果：基因测序证实质粒构建成功,RT—PCR和Western blot结果证实U87细胞转染NUMB shRNA后48hNUMB mRNA及蛋白表达水平均下降,P53蛋白表达水平也明显下调。结论：在U87胶质瘤细胞中,NUMB参与了P53蛋白表达水平的调控,提示NUMB是一个潜在的脑胶质瘤基因及药物治疗的靶点。     

NUMB调控肿瘤增殖的机制研究

目的 探讨膜相关蛋白NUMB调控肿瘤增殖的机制。方法 构建NUMB基因敲除载体,转染Hela细胞后,经抗性筛选获得稳定细胞株,通过实时定量PCR（qRT-PCR）和Western blot检测NUMB基因和蛋白表达,验证NUMB基因敲除效果。采用裸鼠成瘤实验研究NUMB基因敲除对肿瘤增殖的影响;利用流式细胞术和Brdu标记实验检测NUMB缺失对细胞周期的影响;在体外模型中检测细胞周期各个时期多种调控蛋白的表达水平。结果 Western blot及qRT-PCR结果表明NUMB基因敲除的体外模型构建成功;裸鼠成瘤实验显示NUMB基因敲除促进肿瘤增殖;流式细胞术和Brdu标记实验表明NUMB基因缺失加速细胞周期G1/S期转换,促进肿瘤细胞增殖;Western blot检测发现NUMB基因敲除组细胞周期调控蛋白Cyclin-E的表达增加,而P27的表达降低。 结论 NUMB通过调控Cyclin-E以及P27的蛋白水平影响细胞周期,进而调控肿瘤增殖。