缝隙连接蛋白43对双自杀基因系统旁观者效应的影响

Objective： To observe the influence of connexin 43 （Cx43） on the bystander effect induced by cytosine deaminase （CD） and herpes simplex virus thymidine kinase （HSV-tk） coexpression suicide genes system in human cholangiocarcinoma QBC939 cells and transplantation tumors in nude mice. Methods： In vitro, the CD＋tk＋ and CD＋tk＋Cx＋ cells were respectively treated with 5-fluorocytosine （5-Fc） and Ganciclovir （GCV）. The cytotoxic effect was evaluated by MTT method. In order to investigate the influence of Cx43 on the bystander effect, the size of transplantation tumors of the CD＋tk＋ and CD＋tk＋Cx＋ cells was measured before and after application of 5-Fc and GCV. Results： CD and tk genes were stably expressed in transfected QBC939 cells. The increased expression of Cx43 was determined by testing for the presence of Cx43 mRNA by RT-PCR and the presence of Cx43 protein by Western Blot in CD＋tk＋Cx＋ cells. The killing effect of 5-Fc and GCV on CD＋tk＋Cx＋ cells was more effective than that on CD＋tk＋ cells both in vitro and in vivo. Conclusion： Double suicide genes system CD/5-Fc＋tk/GCV could induce remarkable killing effect on cholangiocarcinoma cells in vitro and transplantation tumors in vivo. The cotransfection of Cx43 gene could enhance the bystander effect and hence the inhibition of carcinoma cells.     

Experimental study on the gene therapy of malignant glioma with antisense VEGF RNA

Objective: To study the effect of antisense VEGF RNA on rat C6 gliomas in vivo and find out the feasibility of antiangiogenesis therapy with antisense VEGF RNA formalignant gliomas. Methods: Parental rat C6 glioma cells and C6 cells transfected with antisense VEGF cDNA were implanted intracerebrally and subcutaneously into SD rats as control and transfected group. Rats bearing cerebral and subcutaneous C6 gliomas were treated with antisense VEGF cDNA as treated group and sense VEGF cDNA and empty vector as control of treated group. The general manifestation, survival time, MRI and histopathological changes of all rats were observed. The volume of subcutaneously implanted tumors was determined regularly. In situ hybridization and immunohistochemical staining were used for detection of VEGF gene expression of gliomas while PCNA immunostaining and TUNEL method for examination of proliferation activity and apoptosis of gliomas, respectively. Results: The survival of the rats in transfected and treated group was prolonged.There were two rats surviving over 90 d in the treated group and their tumors disappeared. The VEGF gene expression, the number of microvessels and the proliferation activity were decreased and a large amount of apoptotic cells could be found in cerebral and subcutaneous gliomas in treated and transfected groups. Conclusion:VEGF is one of the candidate genes for gene therapy of malignant gliomas. Antisense VEGF RNA combined with other therapies should be studied further for enhancing the therapeutic effect of malignant gliomas.     

胰腺组织p15、p16抑癌基因CpG岛甲基化研究

Objective： To detect the aberrant methylation patterns in the CpG islands of p16 and p15 tumor suppressor genes, and to analyze its correlation with pancreatic carcinogenesis and with clinicopathological characteristics of patients with pancreatic cancer （PC）. Methods： The methylation-specific polymerase chain reaction （MSP） method was used to monitor methylation patterns in the CpG islands of p15 and p16 genes from 29 cases of PC and 3 cases of chronic pancreatitis （CP） paraffin-embedded tissue, as well as 2 cases of normal liver tissues and 12 cases of normal blood samples. Results： p15 and p16 genes were detected to show unmethylation patterns and no amplification using methylation-specific primers in control group. The aberrant methylation rates of p16 in carcinoma tissue and adjacent noncarcinoma tissue were 37.9% （11 of 29 cases） and 34.5% （10 of 29 cases） respectively. Of the 11 aberrant methylated samples, 5 showed complete methylation and 6 hemimethylation. The methylation rates of p15 gene in carcinoma tissue and adjacent noncarcinoma tissue were 27.5% （8/29） and 24.4% （7/29） respectively. Of the 8 aberrant methylated samples, 3 showed complete methylation and 5 hemimethylation. In 6 PC samples, aberrant methylation in CpG islands of both p15 and p16 genes existed simultaneously. The aberrant methylation patterns in CpG islands of p15 and p16 genes had no close correlation with the clinicopathological characteristics （age, sex, smoking, volume of primary tumor, differentiation, clinical stage and histological classification） of the patients with PC （P〉0.05）. Conclusion： The aberrant methylation in CpG islands of p15 and p16 genes could be regarded as an early molecular event in PC and had no close correlation with the clinicopathological characteristics of the patients with PC.     

The effect and significance on Akt and PTEN expression in melanoma B16 cells with chamaejasme extract

Objective： The aim of this study was to investigate the effect on Akt and PTEN expression and the mechanism of proliferation and apoptosis of melanoma B16 cells treated with chamaejasme extract. Methods： The expressions of Akt and PTEN of B16 cells treated with different concentrations of chamaejasme extract were detected with immunohistochemical method, cell apoptosis index （AI） was calculated with in situ labeling method. Results： Akt expressions of B16 cells treated with different concentrations of chamaejasme extract were significantly lower than the control group, while the PTEN expres- sions significantly up-regulated, and the effects appeared to be dose-related （P 〈 0.05）. The Akt/AI of B16 cells treated with different concentrations of chamaejasme extract was significantly lower than the control group, all the parameters had ex- tremely difference （F = 24.58, P 〈 0.05）. Conclusion： Chamaejasme extract can inhibit proliferation and induce apoptosis of malignant melanoma B 16 cells by down-regulating the expression of Akt and up-regulating the expression of PTEN.     

Effects of Promoter Region 5＇CpG Island Demethylation on the Biological Behavior of Human Colorectal Cancer RKO Cells in Vitro

OBJECTIVE To explore the relationship between the methylation status of the promoter 5＇CpG island region and the biological behavior of human colorectal cancer RKO cells in vitro. METHODS RKO cells were treated with a selective DNA methyltransferase inhibitor-5-aza-2＇-deoxycytidine （5-aza-CdR） for 72 h. Methylationspecific PCR （MSP）, T-A cloning and DNA sequence analysis were used to determinate the 5＇CpG island methylation status of the p16/CDKN2 tumor suppressor gene. Cell growth, morphological changes and apoptosis were analyzed by the MTT assay, flow cytometry, fluorescence staining and electron microscopy. RESULTS The 5＇CpG island of the p16/CDKN2 tumor suppressor gene in RKO cells was a typically hypermethylated. The DNA methyltransferase inhibitor （5-Aza-CdR） effectively reversed the hypermethylation status of the promoter region. With demethylation, RKO cell growth was suppressed, the cells doubling times were prolonged （P〈0.01） and apoptosis was induced, which showed a relationship. CONCLUSION A selective DNA methyltransferase （DNMT） inhibitor can inhibit proliferation by demethylation in 5＇CpG islands, and may be a potential new therapy target for colorectal cancer.     

CK2 inhibitor CX4945 reverses cisplatin-resistance of lung cancer A549/DDP cells北大核心CSCD

Objective: To investigate the effect of CK2 (casein kinase 2) inhibitor CX4945 on the cisplatin (DDP)-resistance of lung cancer A549/DDP cells and the underlying molecular mechanism. Methods: The CCK-8 assay was used to detect the half maximal inhibitory concentration (IC50) of DDP in lung cancer A549 and A549/DDP cells, and to compare the DDP-resistance of two cell lines. The effect of CX4945 on DDP-resistance of A549/DDP cells was tested by CCK-8 method. Western blotting was used to detect the expressions of Wnt signaling pathway-related proteins (CK2α, β-catenin and cyclin D1), drug resistance-related proteins [multidrug resistance-associated protein 1 (MRP1) and lung resistance-related protein (LRP)] and apoptosis-related protein [cleaved caspase-3 (c-caspase-3)] in A549 and A549/DDP cells treated with DDP or not. The A549/DDP cells were treated with no drug (as the control group), CX4945, DDP and their combination (as CX4945+DDP group), then the expressions of Wnt signaling pathway-, drug resistance- and apoptosis-related proteins were detected by Western blotting, and the apoptosis of A549/DDP cells was detected by FCM method. Results: The IC50 value of DDP in A549/DDP cells was 4.59 times higher than that in A549 cells, and the DDP-resistance of A549/DDP cells was decreased by CX4945 pretreatment (P < 0.001). The expression levels of CK2α, β-catenin, cyclin D1, MRP1 and LRP proteins were significantly increased in A549/DDP cells as compared with A549 cells (all P < 0.001), and the levels of these proteins in A549/DDP cells were further increased after DDP treatment (all P < 0.001). In A549 cells after treatment with DDP, the expression levels of CK2α, β-catenin and cyclin D1 proteins were reduced (all P < 0.01), but the levels of MRP1 and LRP proteins were not significantly changed (both P > 0.05). Compared with the control group and DDP group, the expression levels of β-catenin, cyclin D1, MRP1 and LRP proteins in A549/DDP cells of CX4945 group and CX4945+DDP group were significantly declined (all P < 0.01). In addition, the apoptosis rate of A549/DDP cells and the expression level of c-caspase-3 in CX4945+DDP group were significantly higher than those in the control group and DDP group (all P < 0.001). Conclusion: CK2 inhibitor CX4945 can reverse the DDP resistance of lung cancer A549/ DDP cells through blocking Wnt signal pathway and decreasing the expressions of drug resistance-relatied proteins. © 2019 by TUMOR.     

The inhibiting effects of Laggera alata flavone on human ovarian cancer HO-8910 cells proliferation and its mechanism in vitro

The purpose of this study was to investigate the effect of Laggera alata flavonen （LAF） on the inhibit- ing effect of human ovarian cancer HO-8910 cells proliferation and its possible mechanism in vitro. Methods： Human ovarian cancer HO-8910 cells were cultured in vitro. Inhibitory effect of LAF on the viability of HO-8910 cells was evaluated by the MTT assay. Apoptotic effect of different concentrations of LAF on HO-8910 cells was assessed by AO/EB staining and FCM with propidium iodide （PI） staining. Expression of proteins related to apoptosis was analyzed by Western blot. Results： LAF significantly inhibited the viability of HO-8910 cells proliferation in a dose-dependent and time-dependent manner, there were statistical significance compared with NS group （P 〈 0.05）, and the ICso was 4.28 pg/mL for 48 h. The cells treated with LAF showed typical morphological change and apoptotic rate increased by FCM in a dose-dependent, and there was notable dif- ference compared with NS group （P 〈 0.05）. Western blot showed that expression of Fas, caspase-8, tBid and Cyto-c proteins were up-regulated after treatment with LAF for 48 h in a concentration dependent. Conclusion： LAF could inhibit HO-8910 cells proliferation and induce apoptosis, which may be through the pathway of death receptor in vitro.     

EFFECTS AND MECHANISMS OF ENDOSTATIN ON THE GROWTH OF OVARIAN CANCER SKOV3 CELLS IN VITRO AND IN VIVO

Objective： To evaluate the inhibitory effect of Endostatin on ovarian cancer cell line SKOV3 and to investigate the possible mechanism of the inhibition. Methods： Using MTT, transmission electron microscope （TEM） and immunocytochemistry, the effects of Endostatin on the proliferation of SKOV3 cells were studied. Nude mice were subcutaneously implanted with SKOV3 cells. The cell apoptosis of implanted tumor was detected by TUNEL and TEM. The expressions of bcl-2 and bax in implanted tumor tissues were measured by RT-PCR and immunohistochemistry. Results： Endostatin significantly inhibited the proliferation of SKOV3 cells in vitro （P〈0.01） and induced cell apoptosis, whereas the expressions of bcl-2 and bax were not changed obviously in SKOV3 cell treated with Endostatin. The mean tumor weight of Endostatin treated group was markedly lower than that of PBS control group （P〈0.05）. The expression of bcl-2 was down-regulated in Endostatin treated group, but bax was not influenced. Conclusions： The results demonstrated that Endostatin might have anti-tumor effect on ovarian carcinoma. One of the important mechanisms of Endostatin effect of anti-angiogenic and anti-tumor activities might involve regulating the bcl-2/bax expression and inducing apoptosis.     

5-氮杂-2'-脱氧胞苷对肺癌细胞H460生物学行为及抑癌基因RASSF1A表达的影响

 目的　观察5-氮杂-2'-脱氧胞苷（5-Aza-CdR）对肺癌细胞H460的生物学行为及RASSF1A mRNA表达的影响。方法　5-Aza-CdR处理H460细胞,通过MTT方法、平板克隆试验观察细胞生长活性的变化,PCR检测RASSF1A甲基化状态,Western blotting法检测RASSF1A的蛋白表达,流式细胞术进行细胞周期分析。结果　H460细胞经5-Aza-CdR处理后,与未处理组相比,生长速度出现不同程度减慢,克隆形成率明显降低,RASSF1A甲基化程度降低,延缓H460细胞周期G1／S进程,使细胞阻滞于G1期。结论　在肺癌细胞系中,RASSF1A基因甲基化可能导致其表达缺失,而5-Aza-CdR能够恢复RASSF1A基因的表达,为肺癌的去甲基化治疗提供理论依据。     

宫颈癌细胞系RASSFIA基因启动子及第1外显子区甲基化状态的研究

背景与目的：抑癌基因Ras相关区域家族1A (Ras association domain family 1A,RASSF1A)启动子及第1外显子区CG位点高甲基化导致该基因沉默与多种恶性肿瘤的发生发展相关。本研究旨在探讨宫颈癌细胞系RASSFIA基因启动子及第1外显子区甲基化状态以及甲基化转移酶抑制剂5-氮杂-2’-脱氧胞苷(5-Aza-2’deoxycytidine,5-Aza-dc)作用对RASSFIA基因表达的影响。方法：采用5 μmol/L(低浓度)和10 μmol/L(高浓度)的5-Aza-dc作用于HeLa、Caski、HT-3以及C-33A等4种宫颈癌细胞系,分别采用甲基化特异PCR (methylation-specific PCR,MSP)和亚硫酸盐基因组测序法(bisulfite genome sequencing,BGS)检测5-Aza-dc处理前后RASSF1A基因启动子及第1外显子区甲基化状态,RT-PCR检测干预前后RASSF1A基因mRNA的转录表达。结果：HeLa和Caski两种HPV阳性细胞系RASSF1A基因启动子及第1外显子区均呈低甲基化状态,mRNA表达阳性。低浓度和高浓度5-Aza-dc作用后,mRNA表达未见明显改变(F_HeLa=3.003,P=0.125;F_Caski=0.045,P=0.956)。HT-3和C-33A两种HPV阴性宫颈癌细胞系RASSF1A基因启动子及第1外显子区则表现为高度甲基化状态,mRNA表达受到抑制。低浓度和高浓度5-Aza-dc作用后,HT-3和C-33A细胞系RASSF1A基因启动子及第1外显子区CG位点甲基化程度降低,检测到其mRNA表达,高浓度5-Aza-dc作用组表达水平明显高于低浓度组和细胞对照组(F_HT-3=18.002,P=0.03;F_C-33A=17.179,P=0.03),LSD-t检验显示差异有统计学意义(P<0.05)。结论：HPV阳性和HPV阴性宫颈癌细胞系中RASSFIA基因启动子及第1外显子区甲基化状态不同;RASSF1A基因启动子及第1外显子区的高甲基化可抑制该基因表达;5-Aza-dc处理可使RASSF1A基因启动子及第1外显子区去甲基化,重新激活基因的表达,这种作用在一定范围内有剂量依赖性。     

CXCR4 抑制剂LPS 对胆管癌细胞株QBC939生物学行为的影响

目的:探讨人胆管癌细胞株QBC 939 中CXCR4 基因的表达,及LPS 对CXCR4 表达及生物学行为的影响。方法:RT-PCR 和Western blot法检测胆管癌细胞株QBC 939 中CXCR4 mRNA 及蛋白的表达,与不同浓度LPS 干预后CXCR4 mRNA 及蛋白表达的变化;MTT 法和平板克隆形成试验检测LPS 对QBC 939 细胞生长及克隆形成的抑制作用;趋化试验检测LPS 对QBC 939细胞趋化侵袭能力的影响。结果:QBC 939 细胞中有CXCR4 mRNA 及CXCR4 蛋白的表达明显,LPS 能有效的抑制QBC 939 细胞中CXCR4 mRNA 及CXCR4 蛋白的表达,且具有浓度相关性。不同浓度的LPS 对胆管癌细胞株QBC 939 的增殖影响不同,24h 内各浓度LPS 对细胞增殖均无明显抑制,LPS 浓度为0.1 μ g/mL 时,48h 内无明显影响,为1.0 μ g/mL、5.0 μ g/mL 时,QBC 939 细胞生长受到明显抑制,72h 各浓度LPS 对细胞增殖均有明显抑制作用;平板克隆形成试验显示对照组细胞培养第10天即可见明显克隆体形成,至第14天时克隆体数目多、体积大。而试验组细胞于培养第13天时才出现克隆体,且克隆体数目少、体积小。CXCL12（SDF-1）对QBC 939 细胞有明显的趋化作用,对照组细胞趋化率为53.5% ,LPS 各浓度组细胞趋化率明显低于对照组。结论:胆管癌细胞株QBC 939 中CXCR4 mRNA 及CXCR4 蛋白呈阳性表达;CXCR4 抑制剂LPS 能有效抑制胆管癌细胞株QBC 939 的生长与转移能力,CXCR4 可能成为胆管癌基因治疗的靶点之一。      

Delta DNMT3B variants regulate DNA methylation in a promoter-specific manner

DNA methyltransferase 3B (DNMT3B) is critical in de novo DNA methylation during development and tumorigenesis. We recently reported the identification of a DNMT3B subfamily, DeltaDNMT3B, which contains at least seven variants, resulting from alternative pre-mRNA splicing. DeltaDNMT3Bs are the predominant expression forms of DNMT3B in human lung cancer. A strong correlation was observed between the promoter methylation of RASSF1A gene but not p16 gene (both frequently inactivated by promoter methylation in lung cancer) and expression of DeltaDNMT3B4 in primary lung cancer, suggesting a role of DeltaDNMT3B in regulating promoter-specific methylation of common tumor suppressor genes in tumorigenesis. In this report, we provide first experimental evidence showing a direct involvement of DeltaDNMT3B4 in regulating RASSF1A promoter methylation in human lung cancer cells. Knockdown of DeltaDNMT3B4 expression by small interfering RNA resulted in a rapid demethylation of RASSF1A promoter and reexpression of RASSF1A mRNA but had no effect on p16 promoter in the lung cancer cells. Conversely, normal bronchial epithelial cells with stably transfected DeltaDNMT3B4 gained an increased DNA methylation in RASSF1A promoter but not p16 promoter. We conclude that promoter DNA methylation can be differentially regulated and DeltaDNMT3Bs are involved in regulation of such promoter-specific de novo DNA methylation.     

索拉非尼及PI3K、mTOR抑制剂对肝胆肿瘤细胞增殖及Ghrelin基因表达的影响

目的 探讨索拉非尼及磷脂酰肌醇3激酶（PI3K）、哺乳动物雷帕霉素靶蛋白（mTOR）抑制剂对肝胆肿瘤细胞增殖及Ghrelin（GHRL）基因表达的影响。方法 收集体外常规培养的肝癌SMMC7721细胞和胆管癌QBC939细胞,经不同浓度（0、50、100、200 μmol/L）索拉非尼、LY294002（PI3K抑制剂）及Rapamycin（mTOR抑制剂）处理48 h后,采用MTS细胞活性检测试剂盒检测SMMC7721、QBC939细胞的增殖率,实时定量PCR（qPCR）检测SMMC7721、QBC939细胞中GHRL 基因的mRNA水平。结果与对照组相比,LY294002、索拉非尼和Rapamycin处理后的SMMC7721、QBC939细胞的增殖率均降低,差异有统计学意义（P＜0.05）,且随着药物浓度的增加,两种细胞的增殖率均降低（P＜0.05）。qPCR结果显示,经LY294002和索拉非尼处理48 h后的SMMC7721细胞中GHRL mRNA水平与对照组的差异无统计学意义（P＞0.05）;与对照组相比,随着Rapamycin作用浓度的升高,实验组SMMC7721细胞的GHRL mRNA水平升高,差异有统计学意义（P＜0.05）;经LY294002、索拉非尼和Rapamycin处理的QBC939细胞中GHRL mRNA水平高于对照组,差异有统计学意义（P＜0.05）。结论 三种药物均可以抑制肝癌和胆管癌细胞的增殖并促进QBC939细胞的GHRL表达,但仅Rapamycin能上调SMMC7721肝癌细胞的GHRL基因表达。GHRL基因表达与肝癌和胆管癌的发生可能有密切关系。     

A phase II study of epigenetic therapy with hydralazine and magnesium valproate to overcome chemotherapy resistance in refractory solid tumors.

BACKGROUND: Epigenetic aberrations lead to chemotherapy resistance; hence, their reversal by inhibitors of DNA methylation and histone deacetylases may overcome it. PATIENTS AND METHODS: Phase II, single-arm study of hydralazine and magnesium valproate added to the same schedule of chemotherapy on which patients were progressing. Schedules comprised cisplatin, carboplatin, paclitaxel, vinorelbine, gemcitabine, pemetrexed, topotecan, doxorubicin, cyclophosphamide, and anastrozole. Patients received hydralazine at 182 mg for rapid, or 83 mg for slow, acetylators, and magnesium valproate at 40 mg/kg, beginning a week before chemotherapy. Response, toxicity, DNA methylation, histone deacetylase activity, plasma valproic acid, and hydralazine levels were evaluated. RESULTS: Seventeen patients were evaluable for toxicity and 15 for response. Primary sites included cervix (3), breast (3), lung (1), testis (1), and ovarian (7) carcinomas. A clinical benefit was observed in 12 (80%) patients: four PR, and eight SD. The most significant toxicity was hematologic. Reduction in global DNA methylation, histone deacetylase activity, and promoter demethylation were observed. CONCLUSIONS: The clinical benefit noted with the epigenetic agents hydralazine and valproate in this selected patient population progressing to chemotherapy' and re-challenged with the same chemotherapy schedule after initiating hydralazine and valproate' lends support to the epigenetic-driven tumor-cell chemoresistance hypothesis (ClinicalTrials.gov Identifier: NCT00404508).     

Promoter hypermethylation of RASSF1A and RUNX3 genes as an independent prognostic prediction marker in surgically resected non-small cell lung cancers

Aberrant methylation of promoter CpG islands is known to be a major inactivation mechanism of the tumor suppressor and tumor-related genes. Some published studies suggest a relationship to exist between the methylation status of several genes and the prognosis in non-small cell lung cancer (NSCLC); hypermethylation of the specific genes may be expected to serve as a biomarker for the prognosis, after a curative resection of NSCLC. To determine the relationship between the methylation status of the tumor suppressor and the tumor-related genes, and the clinicopathologic characteristics, including the survival rate, in patients with NSCLC after a surgical resection, we studied methylation in 10 genes (DAPK, FHIT, H-cadherin, MGMT, p14, p16, RAR-beta, RASSF1A, RUNX3, and TIMP-3) in 101 NSCLC cases by methylation-specific PCR (MSP). The methylation frequencies of the 10 genes examined in NSCLC were 26% for DAPK, 34% for FHIT, 26% for H-cadherin, 14% for MGMT, 8% for p14, 27% for p16, 38% for RAR-beta, 42% for RASSF1A, 25% for RUNX3, and 12% for TIMP-3. Clinicopathologically, the patients with all stages of disease who had positive RASSF1A, RUNX3, or H-cadherin methylation status were found to have a significantly shorter duration of survival, as compared with the patients with a negative methylation status for those genes (RASSF1A:P=0.023, RUNX3:P=0.035, H-cadherin:P=0.039) in univariate analysis. Thereafter, while limiting our examination to patients with stage I disease, the patients who had a positive RASSF1A or RUNX3 methylation status were found to have a significantly shorter duration of survival, in comparison to the patients with negative methyaltion status for each of those genes (RASSF1A:P=0.022, RUNX3:P<0.01) in univariate analysis. Next, the histological differences were recognized that the patients with RUNX3 methylation had a shorter duration of survival in adenocarcinomas (ACs) (P=0.045), in contrast to those with RASSF1A methylation who had a shorter duration of survival in squamous cell carcinomas (SCCs) (P=0.021). In multivariate analysis, both positive RASSF1A methylation status, and positive RUNX3 methylation status were found to be independent prognostic factors (RASSF1A:P=0.031, RUNX3:P=0.028), as was TNM stage (P=0.004) and pleural involvement (P=0.037). In conclusion, the hypermethylation of RASSF1A or RUNX3 gene is therefore a useful biomarker to predict the prognosis in NSCLC, particularly RASSF1A due to SCCs and RUNX3 due to ACs.     

食管鳞癌抑癌基因甲基化表达的相关性分析

[目的]研究食管鳞癌肿瘤组织及外周血多基因甲基化状态,以及不同基因甲基化的相关性。[方法]应用real-time MSP技术对76例食管鳞癌患者肿瘤组织、配对的癌旁正常组织、术前外周血中APC、RARβ2、CDH1、p16INK4α、RASSF1A抑癌基因的甲基化状态进行检测。随机选取60名年龄配对的健康志愿者外周血浆DNA作对照。[结果]肿瘤组织APC、RARβ2、CDH1、p16INK4α、RASSF1A的甲基化率显著高于对应癌旁正常组织（P=0.000）。术前外周血中这5种基因的甲基化率显著高于健康对照组（P=0.000）。RARβ2、CDH1、p16INK4α、RASSF1A甲基化有显著性相关,APC与这4个基因甲基化无相关性。[结论]食管癌患者癌组织及外周血抑癌基因APC、RARβ2、CDH1、p16INK4α、RASSF1A高甲基化,RARβ2、CDH1、p16INK4α、RASSF1A甲基化有显著相关性。     

5氮杂脱氧胞苷对鼻咽癌细胞RASSF1A基因甲基化和mRNA表达的影响

目的:研究5氮杂脱氧胞苷对鼻咽癌CNE2细胞中RASSF1A基因甲基化和mRNA表达的影响。方法:用不同浓度(0、5、10、20μmol/L)5氮杂脱氧胞苷处理CNE2细胞,采用甲基化特异性PCR(MSP)法对处理后细胞中RASSF1A基因甲基化状态进行检测;并用SYBR Green qReal Time-PCR法检测RASSF1A mRNA的表达。结果:阴性对照组CNE2细胞中,RASSF1A基因呈完全甲基化状态,当用5μmol/L 5氮杂脱氧胞苷处理后,CNE2细胞出现非甲基化产物,20μmol/L 5氮杂脱氧胞苷处理后,CNE2细胞甲基化状态完全被逆转,均为非甲基化产物。阴性对照组CNE2细胞RASSF1A基因呈低表达,经5～20μmol/L 5氮杂脱氧胞苷处理后,RASSF1A mRNA的相对表达量逐渐增加,10和20μmol/L 5氮杂脱氧胞苷处理组,RASSF1A mRNA表达水平均明显高于阴性对照组(P0.01);且20μmol/L处理组明显高于5μmol/L处理组(P0.01)。结论:CNE2细胞RASSF1A基因甲基化可以被5氮杂脱氧胞苷逆转,且5氮杂脱氧胞苷可促进RASSF1A mRNA的表达。