Sonic hedgehog elevates N-myc gene expression in neural stem cells

Proliferation of neural stem cells is regulated by the secreted signaling molecule sonic hedgehog. In this study, neural stem cells were infected with recombinant adeno-associated virus expressing sonic hedgehog-N-enhanced green fluorescent protein. The results showed that overexpression of sonic hedgehog in neural stem cells induced the increased expression of Gill and N-myc, a target gene of sonic hedgehog. These findings suggest that N-myc is a direct downstream target of the sonic hedgehog signal pathway in neural stem cells. Sonic hedgehog and N-myc are important mediators of sonic hedgehog-induced proliferation of neural stem cells.

靶向MYC基因抗肿瘤研究进展

MYC是研究最为广泛的原癌基因之一,属于碱性螺旋-环-螺旋亮氨酸拉链(bHLH-Zip)DNA结合蛋白超家族,通过与MAX形成MYC-MAX异二聚体发挥功能。MYC影响蛋白质合成、细胞黏附、增殖、分化、细胞周期、代谢、细胞凋亡和血管形成等多种生物学过程。因其结构与位置的特殊性,难以直接靶向,针对MYC的治疗策略是研究的热点,本文将系统回顾MYC基因的结构、功能和其抑制剂的研究进展,为靶向MYC治疗肿瘤提供新思路。

猫CDH1基因在过表达c-MYC成纤维细胞中的表达变化及生物信息学分析

[目的]试验旨在研究骨髓细胞瘤病毒癌基因同源物(myelocytomatosis viral oncogene homolog, c-MYC)对猫成纤维细胞的影响及其与E-钙黏蛋白(cadherin 1,CDH1)基因表达和分子特性的关系,为将其应用于猫肿瘤疾病防治和组织损伤修复提供依据。[方法]通过组织贴壁法对猫胎儿成纤维细胞进行分离培养,利用电转仪将PB-TRE-c-MYC质粒转染至细胞并观察细胞形态,利用实时荧光定量PCR检测CDH1基因的表达情况,并通过生物信息学软件分析CDH1蛋白的理化性质和结构特征。[结果]过表达c-MYC导致细胞形态发生变化,从间质细胞的长梭型向上皮细胞的鹅卵石状发生转变,且使上皮细胞标志基因CDH1的表达极显著上调(P<0.01)。生物信息学分析显示,猫CDH1蛋白有881个氨基酸,其中含量最多的是亮氨酸,定位于细胞膜,存在4个CA结构域,介导细胞与细胞的接触,属于亲水性的酸性蛋白,主要由无规则卷曲组成,可能存在由Sec易位子转运并被信号肽酶Ⅰ(Sec/SPⅠ)切割的信号肽位点。[结论]猫CDH1基因的表达可被外源性重编程因子c-MYC激活,其编码的钙黏蛋白可促进猫胎儿成纤维细胞的间质-上皮转化,以抑制细胞癌化。

c-Myc Knockout as a Model for Gene Editing for Training Healthcare Professional Students

Correction of genetic errors, commonly known as gene editing, holds promise to treat diseases with unmet medical needs. However, gene therapy trials do encounter unwanted outcomes, because of an incomplete understanding of the disease states, and gene therapy processes, among others. This situation encourages a concept that healthcare professionals receiving laboratory research training will not only identify inadequacies in basic biomedical knowledge of gene therapies but also provide tangible refinements. To this end, we have undertaken the PharmD student training in gene editing in a basic research laboratory setting. As a model, MYC gene was chosen for knockout using CRISPR-Cas9 method in HT29 and OVCAR8 cells. Students were involved in the design of MYC-specific gRNAs, subcloning into Cas9-carrying plasmid, and selection of knockout clones from the transfected cells. Subsequently, genomic DNA isolation and sequencing, analysis of clonal DNA sequences using online bioinformatics tools, western blotting, cell proliferation and cell division cycle experiments, were performed to characterize the MYC knockout clones. Results presented in this communication suggest that healthcare professionals who received laboratory training gain a better understanding of the disease states and mechanisms, gene therapy protocols, limitations of gene therapies, ability to critically evaluate the literature and confidence in the oversight of gene therapies in the clinic.

N-MYC及NDRG1在胃癌组织中的表达及对胃癌细胞生物学特性的影响

目的分析N-MYC及N-MYC下游调节基因1(NDRG1)在胃癌组织中的表达及对胃癌细胞生物学特性的影响。方法收集2021年1月至2023年5月于该院行手术切除且经病理确诊为胃癌的82例患者的胃癌组织及癌旁正常组织,采用实时荧光定量PCR(qPCR)检测N-MYC、NDRG1 mRNA相对表达量,收集患者临床资料,分析N-MYC、NDRG1 mRNA表达与患者临床病理特征关系。选择对数生长期NCI-N87细胞,将N-MYC干扰质粒(si-N-MYC)与其阴性对照(si-NC)分别转染到NCI-N87细胞中,记为si-NC组、si-N-MYC组;将si-N-MYC分别与anti-NC、anti-NDRG1共转染至NCI-N87细胞中,记为si-N-MYC+anti-NC组、si-N-MYC+anti-NDRG1组。采用CCK-8实验检测细胞增殖活性,Transwell侵袭实验检测细胞侵袭能力,Western blotting法检测细胞中N-MYC、NDRG1蛋白表达。结果胃癌组织N-MYC mRNA相对表达量高于癌旁组织(P<0.05),NDRG1 mRNA相对表达量低于癌旁组织(P<0.05)。不同胃癌TNM分期、淋巴结转移、远处转移患者N-MYC、NDRG1 mRNA表达差异有统计学意义(P<0.05)。与si-NC组比较,si-N-MYC组细胞增殖和侵袭能力下降(P<0.05),NDRG1蛋白表达下调(P<0.05)。与si-N-MYC+anti-NC组比较,si-N-MYC+anti-NDRG1组细胞增殖、侵袭能力增加(P<0.05)。N-MYC可靶向调控NDRG1,敲低NDRG1可逆转N-MYC对细胞产生的生物学作用。结论胃癌组织N-MYC mRNA表达上调、NDRG1 mRNA表达下调,二者参与胃癌的发生发展过程,并对胃癌细胞增殖、侵袭等恶性生物学行为有重要调控作用。

N-myc下游调节基因2、微卫星不稳定在不同病理学特征胃癌患者中的表达及意义

目的:探讨N-myc下游调节基因2(NDRG2)、微卫星不稳定(MSI)在不同病理学特征胃癌患者中的表达及意义。方法:回顾性分析2019年1月至2020年12月该院收治的98例行胃癌根治术患者的临床资料,统计胃癌患者NDRG2、MSI的检测结果,比较不同病理学特征胃癌患者NDRG2、MSI的表达情况。结果:临床分期Ⅰ~Ⅱ期、未合并淋巴结转移的胃癌患者NDRG2阳性率高于临床分期Ⅲ~Ⅳ期、合并淋巴结转移的患者,差异均有统计学意义(P<0.05);肿瘤位置在胃窦、Lauren分型为肠型、低分化、临床分期Ⅰ~Ⅱ期、未合并淋巴结转移胃癌患者的MSI阳性表达率高,差异均有统计学意义(P<0.05)。结论:NDRG2在临床分期Ⅰ~Ⅱ期、未合并淋巴结转移的胃癌患者中呈高表达;MSI在肿瘤位置在胃窦、Lauren分型为肠型、低分化、临床分期Ⅰ~Ⅱ期、未合并淋巴结转移的胃癌患者中呈高表达,二者共同参与胃癌的发生发展。

Expression of telomerase hTERT in human non-small cell lung cancer and its correlation with c-myc gene

Objective To investigate the expression of human telomerase catalytic subunit,hTERT, in human non-small cell lung cancer (NSCLC) and its correlations to c-myc gene.Methods hTERT and c-myc mRNA expressions were detected by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). Statistical correlation analysis was made to estimate whether there was interrelation between them.Results Positive rate of hTERT expression in 51 surgically resected lung cancer specimens was 86.3%,significantly higher than that in adjacent non-neoplastic lung tissues and benign lesions,which were 14.3% and 27.3% respectively. No statistical significance was observed between the frequency of hTERT expression and histologic types,degree of differentiation,TNM stages,tumor size or lymph nodes metastases. Correlation analysis revealed that the expression of c-myc gene was significantly related to that of hTERT (correlation coefficient,r =0.633,P <0.001).Conclusions hTERT may be a useful tumor marker in diagnosing lung cancer. Significant correlation between the expression of hTERT and c-myc mRNA indicates that the activation and up-regulation of hTERT might be conferred by over-expression of c-myc gene.

急性髓系白血病患者骨髓细胞c-Myc基因的表达及其临床意义

目的 研究急性髓系白血病(AML)患者骨髓细胞c-Myc基因的表达及其临床意义。方法 选取2018年9月—2020年9月新疆医科大学第一附属医院143例初治AML患者为研究对象。对照组来自20名志愿者的正常骨髓样本。采用实时荧光定量聚合酶链反应(qRT-PCR)检测AML患者骨髓细胞中c-Myc基因的表达,分析其与临床特征及疗效的关系;采用Sanger测序法检测AML患者C-kit 8/17、NPM1、FLT3-TKD/ITD、CEBPa基因突变情况。影响因素的分析采用单因素Cox和多因素逐步Cox回归模型。结果 初治AML患者的c-Myc基因相对表达量高于对照组(P <0.05)。143例AML患者中基因突变患者98例,检出率为68.5%(98/143)。c-Myc基因表达与CEBPa基因突变呈正相关(r=0.174,P=0.037)。c-Myc基因高表达组2个疗程的完全缓解率为40.0%(36/90),c-Myc基因低表达组为77.4%(41/53)。单因素和多因素逐步Cox回归分析结果显示,c-Myc基因高表达和染色体核型分析异常的AML患者有较差的无事件生存和总生存期。结论 c-Myc基因异常表达在AML发病中可能起重要作用,可作为AML疗效和预后的不良分子标志物。

杨树MYC基因家族成员表达模式研究

[目的]探究bHLH亚家族成员MYC基因在杨树生长发育及对环境响应中的表达模式,为解析茉莉酸信号通路关键基因MYC调控杨树生长发育及抗逆响应提供参考。[方法]利用生物信息学方法鉴定杨树基因组中的MYC基因家族成员并对各成员的基因结构、保守基序进行了系统分析;在此基础上,采用实时荧光定量PCR技术检测了MYC成员在不同组织、不同植物激素响应及逆境胁迫下的表达模式。[结果]毛果杨基因组中含有10个MYC成员,这些成员在进化上相对保守,均具有典型的bHLH结构域,根据进化关系将其分为3个分支。组织表达分析发现,大部分MYC家族成员在根中均具有较高表达量,分枝Ⅱ两对基因在茎中呈相反表达模式。不同激素处理及非生物胁迫条件下MYC基因存在显著表达差异,但基因对之间多存在类似的表达模式。[结论]杨树MYC基因家族成员可能参与不同的生物学过程,研究结果为深入解析杨树MYC基因的功能奠定了基础。

卵泡刺激素对原癌基因c-myc在鸡卵泡上表达的影响

[目的]本试验旨在研究c-myc基因在鸡卵泡上的表达及卵泡刺激素(FSH)对其的诱导作用,为明确c-myc在鸡卵泡发育过程中的相关机制提供理论基础。[方法]体外分离鸡小白卵泡(SWF)、大白卵泡(LWF)、小黄卵泡(SYF)、F4和F1卵泡颗粒层和膜层,检测c-myc mRNA和蛋白的表达;应用50 ng·mL^(-1)FSH处理小黄卵泡36 h,测量卵泡颗粒层的厚度和密度,检测颗粒层和膜层c-myc、标记基因和周期相关基因的表达;体外分离、培养小黄卵泡颗粒细胞,预培养16 h,用siRNA干扰c-myc 24 h后,加入50 ng·mL^(-1)FSH处理24 h,检测c-myc mRNA的表达。[结果]c-myc mRNA在等级前卵泡的颗粒层和膜层的表达水平都显著高于排卵前卵泡,卵泡的颗粒层和膜层上都有c-Myc蛋白表达。与对照组相比,FSH处理后,小黄卵泡颗粒层厚度增加约25.5%(P<0.05),密度增加约27.8%(P<0.01)。在小黄卵泡颗粒层上,FSH降低了c-myc和类固醇激素合成急性调节蛋白(star)mRNA的表达水平(P<0.05),提高了细胞增殖抗原(pcna)和周期蛋白D2(ccnd2)mRNA的表达水平(P<0.01);在卵泡膜层上,FSH提高了c-myc和pcna mRNA的表达水平(P<0.05),极显著提高了ccnd2和star mRNA的表达水平(P<0.01)。FSH能提高c-myc敲减后颗粒细胞c-myc mRNA的表达水平(P<0.05)。[结论]FSH能诱导c-myc在鸡颗粒细胞中的表达,推测c-myc与体外培养的鸡小黄卵泡颗粒细胞的终端分化有关。

Gene expression profiling of MYC-driven tumor signatures in porcine liver stem cells by transcriptome sequencing

AIM:To identify the genes induced and regulated by the MYC protein in generating tumors from liver stem cells.METHODS:In this study,we have used an immortal porcine liver stem cell line,PICM-19,to study the role of c-MYC in hepatocarcinogenesis.PICM-19 cells were converted into cancer cells(PICM-19-CSCs)by overexpressing human MYC.To identify MYC-driven differential gene expression,transcriptome sequencing was carried out by RNA sequencing,and genes identified by this method were validated using real-time PCR.In vivo tumorigenicity studies were then conducted by injecting PICM-19-CSCs into the flanks of immunodeficient mice.RESULTS:Our results showed that MYC-overexpressing PICM-19 stem cells formed tumors in immunodeficient mice demonstrating that a single oncogene was sufficient to convert them into cancer cells(PICM-19-CSCs).By using comparative bioinformatics analyses,we have determined that>1000 genes were differentially expressed between PICM-19 and PICM-19-CSCs.Gene ontology analysis further showed that the MYCinduced,altered gene expression was primarily associated with various cellular processes,such as metabolism,cell adhesion,growth and proliferation,cell cycle,inflammation and tumorigenesis.Interestingly,six genes expressed by PICM-19 cells(CDO1,C22orf39,DKK2,ENPEP,GPX6,SRPX2)were completely silenced after MYC-induction in PICM-19-CSCs,suggesting that the absence of these genes may be critical for inducingtumorigenesis.CONCLUSION:MYC-driven genes may serve as promising candidates for the development of hepatocellular carcinoma therapeutics that would not have deleterious effects on other cell types in the liver.

Expression and Biological Function of N-myc Down-regulated Gene 1 in Human Cervical Cancer

The expression of N-myc down-regulated gene 1 (NDRG1) has previously been reported to be involved in the proliferation,differentiation,invasion and metastasis of cancer cells,but its role in cervical cancer is still unclear.This study aimed to investigate the expression of NDRG1gene in human cervical cancer and its effect on aggressive tumor behaviors.The NDRG1 expression in cervical tissues and cells was detected by RT-PCR.Specific expression plasmid pEGFP-N1-NDRG1-GFP was used to enhance the expression of NDRG1 in human cervical cancer cell lines.The mRNA and protein level of NDRG1 was assessed by RT-PCR and Western blotting,respectively.Its effects on cell proliferation,migration,invasion,cell cycle and apoptosis were detected by MTT,transwell migration assay and flow cytometry (FCM),respectively.The results showed that the expression of NDRG1 in cervical cancer tissues and cells was significantly lower than in normal cervical tissues (P【0.001).After transfection with pEGFP-N1-NDRG1-GFP,the mRNA and protein expression of NDRG1 was up-regulated in Siha cells,which suppressed cell proliferation (P【0.001),induced cell cycle arrest (P【0.05),reduced invasion and migration of Siha cells (P【0.05),but caused no cell apoptosis.Moreover,vascular endothelial growth factor (VEGF),a tumor-induced angiogenesis factor,was markedly reduced and E-cadherin,a cell adhesion molecule,was increased in the cells transfected with pEGFP-N1-NDRG1-GFP.It was concluded that up-regulated NDRG1 may play a role in the suppression of malignant cell growth,invasion and metastasis of human cervical cancer.

N-myc下游调节基因2对巨噬细胞极化及乳腺癌增殖、侵袭和迁移的影响

目的探究N-myc下游调节基因2(N-myc downstream-regulated gene 2,NDRG2)在乳腺癌中的表达及对巨噬细胞极化和乳腺癌增殖、侵袭及迁移的影响。方法生物信息学分析NDRG2在乳腺癌组织中的表达及与临床相关病理特征和预后的关系。免疫荧光检测乳腺癌组织中NDRG2与巨噬细胞分子标志物的定位与表达。构建巨噬细胞与乳腺癌细胞的共培养体系观察巨噬细胞内NDRG2水平改变对乳腺癌细胞增殖、侵袭和迁移的影响。结果NDRG2在乳腺癌组织中表达下调并与不良预后相关,巨噬细胞内NDRG2表达下调促进巨噬细胞向促瘤表型M2极化,NDRG2表达上调则促进巨噬细胞向抑瘤型M1极化,共培养体系中巨噬细胞内NDRG2表达下调可增加乳腺癌细胞增殖、侵袭和迁移能力,从而促进乳腺癌进展。结论巨噬细胞内NDRG2表达下调不仅可以促进巨噬细胞向促瘤型M2转变,还能增强乳腺癌细胞的增殖、侵袭和迁移能力。

Gene therapy with antisense c-myc adenovirus for human gastric carcino-ma cell line in vitro and for implanted carcinoma in nude mice

Objective:To study the effects of recombinant antisense c-myc adenovirus (rAS-c-myc-Ad) on SGG 7901 human gastric carcinoma cell line in for and in nude mice. Methods:The effects of rAS-c-myc-Ad and LacZ-Ad on SGG 7901 gastric carcinoma cells were observed with X-galstaining, MTT, DNA gradient degradation test, TUNEL, flow cytometry, PCR and western blot. The therapeutic effects of rAS-c-myc-Ad on the implanted ax 7901 cells in nude mice were also ob served.Results: rAS-c-myc-Ad significantly inhibited the growth of SGG 7901 cells and induced their apoptosis. After the treatment of rAS-c-myc-Ad, the prolifetion rate of the cells was decreased by 44’ l% in de and SGC 7901 cells failed to form caxcinoma ther they were implanted into nude mice. Injection of rAS-c-myc-Ad into the carcinoma subcutaneously implanted to the nude mice significantly inhibited the growth of the implanted carcinoma with an inhibition rate of 68. 9%. Conclusion: rAS-c- myc- Ad significantly inhibits the growth of SGG 7901 human gastric carcinoma cells in vitro and in nude

Reduction of Repair in c-myc Gene Within HL-60 Induced With DMSO

One of the important advancements in DNA repair research is the demonstration of preferential repair of transcriptionally active DNA in UV-irradiation cells. Experiment results have shown that repair in specific sequence in and around

Expressions of myc and ras gene in human hepatocellular carcinoma by applying the double hybridization in situ

Objective: To establish a method of non-isotope double in situ hybridization in order to detect the expression of two kinds of oncogenes at single cell level simultaneously, and confirm the hypothesis of 'model of stepwise carcinogenesis'. Methods: The method of non-isotope double in situ hybridization was established with the digoxigenin (Dig) and biotin(Bio) labelled probes. The expression of two members of oncogenes of the myc and/or ras gene families (myc and N-ras, myc and K-ras, myc and H-ras, N-ras and K-ras , N-ras and H-ras, K-ras and H-ras) was further studied with the method in 10 cases of Chinese Hepatocellular Carcinomas (HCC). Results : Co-expression of two kinds of oncogenes was detected only in a few cases, reflected by coshowing two different hybridization signals ,i. e. , co-showing of Dig-myc and Bio-H-ras, Dig-myc and Bio-N-ras, Dig-myc and Bio-K-ras was observed in 2 cases, 2 cases and one case, respectively. The common characteristics were that positive cells of myc distributed diffusely, while positive cells of ras diatributed sporadically or locally among the positive cells of myc, and only a few cells exhibited co-showing of two oncogenes at single cell level. There were only 2 cases representing co-showing of two oncogenes in ras gene family (Dig-N-ras and bio-H-ras, Dig-N-ras and Bio-K-ras , respectively). The two kinds of positive cells of different ras gene represented mixed local and sporadical distribution, and co-showing of two signals was found in a few cells at single cell level. Conclusion: There are multiple oncogenes involving in tumorigenesis by their ordered activation. The activation of the ras gene family plays a role in promotion, while the activation of myc is an important event in late stage of tumorigenesis

老年急性缺血性脑卒中患者N-myc下游调节基因3和信号素3A表达及其临床意义

目的分析老年急性缺血性脑卒中患者N-myc下游调节基因3(NDRG3)和信号素3A(SEMA3A)表达及其临床意义。方法选择2020年9月至2022年9月聊城市人民医院老年病科收治的老年急性缺血性脑卒中患者100例(研究组)。研究组根据入院时美国国立卫生研究院卒中量表(NIHSS)评分分为轻度组34例,中度组31例,重度组35例;出院后随访3个月,依照改良的Rankin量表评分分为预后良好组69例,预后不良组31例。另选取同期我院健康体检者100例(对照组)。使用Westernblot法检测外周血单个核细胞(PBMC)中NDRG3、SEMA3A表达,ELISA法检测外周血内皮生长因子、转化生长因子β1、TNF-α、白细胞介素17水平,Spearman等级相关性分析NDRG3、SEMA3A与NIHSS评分的相关性,ROC曲线分析NDRG3、SEMA3A对老年急性缺血性脑卒中患者预后不良的预测价值。结果研究组PBMC中NDRG3、SEMA3A表达较对照组明显升高(1.11±0.16vs0.76±0.13,0.78±0.13vs0.42±0.09,P<0.01)。轻度组、中度组、重度组PBMC中NDRG3、SEMA3A表达明显高于对照组,差异有统计学意义(P<0.01)。预后不良组NDRG3、SEMA3A表达明显高于预后良好组,差异有统计学意义(P<0.01)。Spearman等级相关性分析显示,老年急性缺血性脑卒中患者NIHSS评分与NDRG3、SEMA3A表达呈正相关(r=0.597,P<0.01;r=0.618,P<0.01),NDRG3与SEMA3A表达呈正相关(r=0.477,P<0.01)。ROC曲线分析显示,NDRG3+SEMA3A联合预测的曲线下面积优于NDRG3、SEMA3A单独预测(0.962vs 0.861、0.880,P<0.01)。结论老年急性缺血性脑卒中患者NDRG3、SEMA3A表达上调,且与患者病情严重程度及预后密切相关。

靶向抑制Myc对小鼠LLC全细胞疫苗免疫原性的影响

目的制备小鼠Lewis肺癌(Lewis lung carcinoma,LLC)全细胞疫苗,并探讨该疫苗在提高C57BL/6N小鼠免疫系统对抗LLC方面的作用。方法利用TCGA数据库分析MYC扩增背景下人类肺腺癌(lung adenocarcinoma,LUAD)组织内免疫细胞浸润丰度的变化特点,探讨确定制备LLC全细胞疫苗时紫外线照射的最佳时长。利用小鼠模型,评估靶向抑制Myc的LLC全细胞疫苗在抵抗LLC方面的效果。结果在人LUAD组织样本中,相较于N-MYC低表达组,N-MYC高表达组的激活CD4^(+)记忆T细胞与激活NK细胞浸润丰度显著降低(W=28233、27990,P<0.05),Tregs细胞浸润丰度显著升高(W=36074,P<0.05)。抑制剂处理过的小鼠LLC细胞在经过15 min的紫外线照射后完全失去活性,并且LLC细胞内的c-Myc、N-Myc和PD-L1表达量显著降低(t=6.26~13.51,P<0.05)。在小鼠模型实验中,与Irra组相比,Irra处理组中的小鼠表现出肿瘤生长速度减缓和生存期延长的现象。此外,Irra处理组小鼠的脾脏和肿瘤内CD3^(+)CD8^(+)/CD3^(+)T细胞比值以及血清中的细胞因子TNF-α和IFN-γ表达水平也显著增加(F=54.83~381.10,P<0.05)。结论本研究成功制备了LLC全细胞疫苗。在小鼠实验中,接种靶向抑制Myc的LLC全细胞疫苗能够提高免疫系统对LLC的攻击能力,抑制肿瘤细胞的生长速度,延长小鼠生存期。

EXPRESSION OF c－myc GENE AND BIOSYNTHESIS OF BIOLOGICAL MACROMOLECULES IN ANTISENSE TRANSFECTANT HL_（60）~R－9

The recombinant plasmid PGC was constructed for transcription unit of c-myc gene with diorientation in vitro, to make RNA probes for detection of c-myc mRNA and antisence RNA expression of tranfectant HL-9,which was obtained from HL60 cells transfected with inducible c-myc antisense RNA expression plasmid. The results from HL-9 cells induced by Cd2+ indicated that expression of c-myc antisense RNA increased with Cd2+ concentration and exposure time, while c-myc mRNA expression progressively reduced. Using immunohistochemical technique no c-myc P62 protein expression was detected. The incorporation of 3H-TdR, 3H-UR and 3H-Leu revealed significant suppression of DNA, RNA and protein biosynthesis. It is suggested that the reversion changes previously reported in malignant Phenotypes of HL-9 cells and the inhibition of macromolecular biosynthesis mentioned above were associated with the blockade of c-myc gene expression by its antisense RNA.

Inhibition of N-Myc down regulated gene 1 in in vitro cultured human glioblastoma cells

AIM: To study short ds RNA oligonucleotides(si RNA)as a potent tool for artificially modulating gene expression of N-Myc down regulated gene 1(NDRG1) gene induced under different physiological conditions(Normoxia and hypoxia) modulating NDRG1 transcription, m RNA stability and translation. METHODS: A cell line established from a patient with glioblastoma multiforme. Plasmid DNA for transfections was prepared with the Endofree Plasmid Maxi kit. From plates containing 5 × 107 cells, nuclear extracts were prepared according to previous protocols. The p SUPERNDRG1 vectors were designed, two sequences were selected from the human NDRG1 c DNA(5'-GCATTATTGGCATGGGAAC-3' and 5'-ATGCAGAGTAACGTGGAAG-3'. reverse transcription polymerase chain reaction was performed using primers designed using published information on β-actin and hypoxia-inducible factor(HIF)-1α m RNA sequences in Gen Bank. NDRG1 m RNA and protein level expression results under different conditions of hypoxia or reoxygenation were compared to aerobic control conditions using the Mann-Whitney U test. Reoxygenation values were also compared to the NDRG1 levels after 24 h of hypoxia(P < 0.05 was considered significant).RESULTS: si RNA- and iodoacetate(IAA)-mediated downregulation of NDRG1 m RNA and protein expression in vitro in human glioblastoma cell lines showed a nearly complete inhibition of NDRG1 expression when compared to the results obtained due to the inhibitory role of glycolysis inhibitor IAA. Hypoxia responsive elements bound by nuclear HIF-1 in human glioblastoma cells in vitro under different oxygenation conditions and the clearly enhanced binding of nuclear extracts from glioblastoma cell samples exposed to extreme hypoxic conditions confirmed the HIF-1 Western blotting results. CONCLUSION: NDRG1 represents an additional diagnostic marker for brain tumor detection, due to the role of hypoxia in regulating this gene, and it canrepresent a potential target for tumor treatment in human glioblastoma. The si RNA method can represent an elegant alternative to modulate the expression of the hypoxia induced NDRG1 gene and can help to monitor the development of the cancer disease treatment outcome through monitoring the expression of this gene in the patients undergoing the different therapeutic treatment alternatives available nowadays.