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Precision medicine is a rapidly-developing modality of medicine in human healthcare. Based on each patient׳s unique characteristics, more accurate dosages and drug selection can be made to achieve better therapeutic efficacy and less adverse reactions in precision medicine. A patient׳s individual parameters that affect drug transporter action can be used to develop a precision medicine guidance, due to the fact that therapeutic efficacy and adverse reactions of drugs can both be affected by expression and function of drug transporters on the cell membrane surface. The purpose of this review is to summarize unique characteristics of human breast cancer resistant protein (BCRP) and the genetic variability in the BCRP encoded gene in the development of precision medicine. Inter-individual variability of BCRP/ can impact choices and outcomes of drug treatment for several diseases, including cancer chemotherapy. Several factors have been implicated in expression and function of BCRP, including genetic, epigenetic, physiologic, pathologic, and environmental factors. Understanding the roles of these factors in controlling expression and function of BCRP is critical for the development of precision medicine based on BCRP-mediated drug transport.
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BACKGROUND: The purpose of the present study was to investigate the role of the methylation status of the DACT1 gene on the invasion and metastasis of nasopharyngeal carcinoma cells. METHODS: The levels of methylation and expression of the DACT1 gene in nasopharyngeal carcinoma tissues and CNE2 cells were determined by methylation-specific PCR and RT-PCR, respectively. CNE2 cells were treated with 5-aza-2-deoxycytidine, and the variation in the methylation status of the DACT1 gene was detected, as well as the influence of methylation on invasiveness of nasopharyngeal carcinoma cells. RESULTS: The DACT1 gene was hyper-methylated in 44 of 62 cases of nasopharyngeal carcinoma. The DACT1 gene was hyper-methylated in 32 of 38 cases of nasopharyngeal carcinoma with lymph node metastasis, and the DACT1 gene was hyper-methylated in 7 of 24 cases of nasopharyngeal carcinoma without lymph node metastasis. The DACT1 mRNA level was weakly expressed or not expressed in all nasopharyngeal carcinoma tissues with hyper-methylated DACT1 genes; however, the DACT1 mRNA level was highly expressed in nasopharyngeal carcinoma tissues with low expression of the methylated DACT1 gene. The DACT1 gene was hyper-methylated and not expressed in CNE2 cells that did not have 5-aza-2-deoxycytidine treatment. After 5-aza-2-deoxycytidine treatment, the DACT1 gene was demethylated and the expression of DACT1 was restored. Moreover, the invasion ability was inhibited in CNE2 cells treated with 5-aza-2-deoxycytidine. CONCLUSION: The expression of DACT1 was related to the methylation status. High expression of DACT1 may inhibit the invasion and metastasis of nasopharyngeal carcinoma cells.
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Humans , Male , Female , Nuclear Proteins/genetics , Nasopharyngeal Neoplasms/pathology , DNA Methylation/genetics , Adaptor Proteins, Signal Transducing/genetics , Nasopharyngeal Carcinoma/secondary , Nuclear Proteins/metabolism , Nasopharyngeal Neoplasms/genetics , Promoter Regions, Genetic , DNA Methylation/physiology , Adaptor Proteins, Signal Transducing/metabolism , Nasopharyngeal Carcinoma/genetics , Neoplasm Invasiveness , Neoplasm Proteins/metabolismABSTRACT
AIM:To investigate influence of demethylation/acetylation by 5-Aza-2'-deoxycytidine/trichostatin A(5-Aza/TSA)treatment on B-cell specific phenotype of non-Hodgkin lymphoma cells.METHODS:CD19 promoter-driven reporter with NEO cassette was constructed to realize transfection and stable selection of Hodgkin and non -Hodgkin lymphoma cells.The exogenous CD19 promoter activity in both cell line clusters with and without 5-Aza/TSA treatment was detected and compared.The B-cell specific expression profiling in Eμ-myc transgenic mouse model developed lymphoma was isolated and identified.The effects of 5-Aza/TSA treatment on B-cell specific phenotype were analyzed.RESULTS:Epigenetic modification via 5-Aza/TSA repressed B-cell specific phenotype in B-cell-derived non-Hodgkin lymphoma cells. CONCLUSION:Epigenetic modification of pivotal master repressor genes plays an essential role in B -cell phenotype of both human and murine developed B-cell non-Hodgkin lymphoma cells.
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Objective To investigate effects of 5-Aza-2′-deoxycytidine (5-Aza-CdR) on proliferation of human breast cancer cell line Hs578T,and the methylation status of PRDM10 gene in vitro in this cell line.Methods The human breast cancer cell line Hs578T was cultured with 1,3 and 5 μmol/L DNA methylation inhibitor 5-Aza-CdR respectively, and untreated cells were used as control.Cell proliferation was detected by MTT assay.Methylation-Specific PCR(MSP)was used to detect the methylation status of PRDM10 gene. The mRNA and protein expression levels of PRDM10 gene were detected by RT-PCR and Western blot assay. Results MTT results showed that the higher the concentration of 5-Aza-CdR,and the longer the treatment time,the more significant inhibitory effect on the proliferation of Hs578T cells.Compared with the control group(0 μmol/L),the proliferation of Hs578T was significantly inhibited after the treatment for 72 h in the 1 μmol/L group, and for 48 h in the 3 μmol/L and 5 μmol/L groups (P<0.05). MSP results showed that the higher the concentration of 5-Aza-CdR,the more significant demethylation of PRDM10.Results of RT-PCR and Western blot showed that the higher the concentration of 5-Aza-CdR, the higher the expression levels of mRNA and protein in PRDM10 (P<0.05).Conclusion 5-Aza-CdR could inhibit the cell proliferation of Hs578T,which might be related to the demethylation of PRDM10 gene in the cells.
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Objective To investigate the effects of methylation inhibitor 5-Aza-2'-deoxycytidine (5-Aza-dC) on biological behavior of esophageal squamous carcinoma cell (ESCC) lines KYSE140 and KYSE150. Methods KYSE140 and KYSE150 cell lines were divided into the blank group, the control group and the experimental group. The cells in the blank group didn't do the treatment, and the cells in the control group were added to DMSO 2 μmol/L, while in the experimental group, cells were treated with different concentration (1, 2, 3 and 4 μmol/L) of 5-Aza-dC which affected respectively at different time (24, 48, 72 and 96 h). Cell proliferation was detected by using methyl thiazolyl tetrazolium (MTT) assay and the optimal drug concentration and time point were selected. Transwell assay was performed to detect the change of cell migration and invasion. Flow cytometry was used to observe the effects of drugs on cell apoptosis and cell cycle.The expression of PARP,Caspase-3,CCNB-1,and CCNE-1 were detected by Western blot. Results MTT result showed that the effective function time of 5-Aza-dC on KYSE140 and KYSE150 was 96 h at the concentration of 4 μmol/L. Under this condition, the cell ability of migration and invasion was decreased significantly. The migrated cell number of KYSE140 and KYSE150 respectively in the blank group, the control group and the experimental group was (193.3±8.6), (184.0±10.4), (61.7±7.1) and (112.0±6.4), (101.3± 7.9), (26.3±5.7). The invasive cell number was (47.3±7.3), (38.7±5.1), (8.0±3.9) and (83.3±6.8), (74.7±5.7), (21.0±2.7), respectively. The difference was statistically significant (P <0.05). Flow cytometry revealed that 5-Aza-dC increased the apoptosis of KYSE140 and KYSE150. The apoptosis rate of the blank group, the control group and the experimental group was (2.8±0.3) %, (11.2±0.7) %, (18.6±0.6) % for KYSE140 and (2.7±0.4)%,(9.8±0.4)%,(17.7±0.5)% for KYSE150.Compared with the other two groups,the cell number of G2/M phase in the experimental group was increased remarkably (P < 0.05). PARP and Caspase-3 were sheared evidently and the protein expression of CCNB-1 was up-regulated while the expression of CCNE-1 was down-regulated in the experimental group. Conclusion 5-Aza-dC can inhibit the proliferation and promote apoptosis of ESCC cells.
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Objective:To investigate the effects of 5-aza-2′deoxycytidine(5-aza-dC),a DNA methyltransferase (DNMT)inhibitor, on the methylation status of the RECK gene and the invasion of salivary adenoid cystic carcinoma cell lines.Methods:Methylation-specific PCR,Western blot analysis and quantitative real-time PCR were used to investigate the methylation status of RECK gene and the expression of RECK mRNA and protein in SACC cell lines.The invasive ability of SACC cells was examined by transwell assay. Results:Promoter methylation was only found in ACC-Mcell line and not in ACC-2 cell line.Treatment of ACC-Mcells with 5-aza-dC partially reversed the hypermethylation status of the RECK gene and significantly enhanced the expression level of mRNA and pro-tein of RECK,suppressed ACC-Mcell invasive ability.Conclusion:5-aza-dC can inhibit ACC-Mcell invasion by reversal of hyperm-ethylation status of RECK gene.
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Objective To investigate the effects of 5-aza-2'-deoxycytidine (5-Aza-dC) alone or combined with trichostatin A(TSA) on cell proliferation, promoter methylation and mRNA expression level of PDX-1 gene in pancreatic β cells induced by high glucose toxicity. Method NIT-1 cells were treated in vitro by high glucose (33.3 mmol/L), then divided into five groups, control group, HG grpup, 5-Aza-dC treatment group, TSA interfere group and 5-Aza-dC + TSA group. Proliferation of NIT-1 cells, insulin secretion, promoter methylation and mRNA expression of PDX-1 gene were detected respectively. Results 5-Aza-dC and TSA alone or in combination could promote cell proliferation and recover insulin secretion in NIT-1 cells , could also reduce PDX-1 gene methylation and enhance expression of PDX-1 mRNA. Compared with single-treatment group , combined group was significantly different (all P < 0.05). Conclusion 5-Aza-dC and TSA could activate the expression of PDX-1 and, then recover insulin secretion in NIT-1 cells induced by high glucose. Combination of them had synergistic effect.
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Objective To investigate the effects of 5-Aza-2'-deoxycytidine (5-Aza-CdR) on the apoptosis of A549/DDP cells and the expression of hMLH1 gene.Methods A549/DDP cells were treated with 5-Aza-CdR at 0.5,5,50 μmol/L.The growth curve of A549/DDP cells was investigated by MTT assay.The methylation status of hMLH1 gene was detected by methylation specific PCR (MSP).The expression of hMLH1 mRNA was evaluated by FQ-PCR.The apoptosis rate of A549/DDP cells was analyzed by flow cytometry.Results A549/DDP cells treated with 5-Aza-CdR showed a slow growth in comparison with the control cells,and the growth rates were decreased with the increasing of 5-Aza-CdR concentration.The apoptosis rate after treatment was higher than that before treatment in A549/DDP cells (P ＜ 0.05),and had a positive correlation with 5-Aza-CdR dose (P ＜ 0.001).hMLH1 mRNA expression level was increased in a 5-Aza-CdR concentration dependent manner (P ＜ 0.05).hMLH1 promoter in A549/DDP cells was methylated and hMLH1 mRNA was negatively expressed before treatment,but the mRNA was positively expressed after treatment with 5-Aza-CdR.Conclusions 5-Aza-2'-CdR can induce apoptosis of A549/DDP cells by inducing demethylation of hMLH1 promoter and thereby enhancing hMLH1 gene expression and its tumor suppressor function.
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Objective To detect the methylation status of the promoter of BNIP3 gene in gastric cancer cell lines MKN1,and to explore the mecha?nism of DNA methylation regulating the expression of BNIP3 in gastric cancer cells. Methods The methylation status of BNIP3 promoter was de?tected by bisulfate sequencing PCR. Reverse transcription PCR was used to evaluate BNIP3 mRNA expression. MKN1 cells were treated with 5?Aza?2′?deoxycytidine(5?Aza?CdR),and after the treatment,the methylation status and BNIP3 mRNA expression were observed. Chromatin immuno?precipitation(ChIP)was used to determine the combination of BNIP3 with DNA methyltransferase 1(DNMT1). Results The promoter DNA of BNIP3 in MKN1 cells was in state of hypermethylation. Compared to the control group,methylation status and mRNA expression of BNIP3 in the drug treatment group(the 5?Aza?CdR concentration was 10μmol/L)were reversed,which showed statistical differences(P<0.05). 5?Aza?CdR inhibited the combination of BNIP3 with DNMT1. Conclusion CpG island methylation regulates BNIP3 gene expression in MKN1 cells. DNA methylation is related with the binding between the promoter of BNIP3 and DNMT1.
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Objective Methylation of anti-oncogene can be demethylated by related drugs which can help the inactivated gene to express again .This study aims to study the effects of the demethylating agent 5-Aza-2′-deoxycytidine on the growth of human thyroid papillary cancer cell line TPC-1 and mRNA and protein expres-sion of KLF4.Methods TPC-1 cells were treated with different concentration of 5-Aza-CdR.MTT was used to detect the influence of 5-Aza-CdR on cell proliferation .RT-PCR was used to detect mRNA and protein expression levels of KLF4.Results After being treated with 5-Aza-CdR for 24 hours, 48 hours, and 72 hours, the growth of TPC-1 cells was inhibited and the inhibition was in time and concentration depended manner .After treatment with 5-Aza-CdR, mRNA and protein expression levels of KLF 4 were increased, and the difference had statistical significance(P<0.05).Conclusion 5-Aza-CdR can inhibit the cell viability of TPC-1 cells through upregulat-ing KLF4 expression , which may provide experimental basis for 5-Aza-CdR in treating thyroid cancer .
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Objective:To investigate the effect of the adoptive transfer of CD4+CD25+Foxp3+regulatory T cells ( iTregs) induced by 5-aza-2′-deoxycytidine (5AzaD) on pregnant outcome of the abortion-prone mice.Methods:Sixty cases of female CBA/J × male DBA/2J abortion-prone matings were taken as study group,the CD4+T cells from spleen of twenty female CBA/J mice were separated by magnetic activated cell sorting (MACS),5AzaD was applied to the conversion of CD4+CD25-T cells to iTregs,the expression of Foxp3 in Tregs was characterized by flow cytometry analysis before and after epigenetic modification.The purified iTregs were injected into abortion-prone mice on day 1 or 4 of pregnancy,respectively,which were used as therapy groups,and then the embryo resorption rate was counted on day 14 of pregnancy.Results:After the treatment of 5AzaD,the percentage of iTregs in CD4+T cells was (41.50±8.03)%.The embryonic absorption rates of the two therapy groups were 10.47%(on day 1 of pregnancy) and 21.69%(on day 4 of pregnancy) ,respectively ( P<0.05 ) .Conclusion: Epigenetic modication of CD4+CD25-T cells may solve the problem of nTregs deficiency,particularly adoptive therapy of 5AzaD-induced iTregs at early stage of pregnancy can maintain normal pregnancy.
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Objective To investigate the effect of 5-aza-2'deoxycytidine (5-Aza-CdR) on proliferation and expression of RASSF1 A gene in human ovarian cancer cell line SKOV3 and 3AO.Methods SKOV3 and 3AO cells were treated with different concentrations (0.5,5,50 μmol/L) of DNA methyltransferase inhibitor 5-Aza-CdR.RT-PCR and Western Blot were adopted to detect expression of mRNA and protein of RASSF1A gene before and after treatment with 5-Aza-CdR respectively.Results Compared with control group,when the 5-Aza-CdR concentration was 0.5,5,50 μmol/L after drug treatment,human ovarian cancer cells could significantly inhibit tumor cell growth; SKOV3 and 3AO cells in control group were observed weaker expression of RASSF1A mRNA.After treated with 5-Aza-CdR,the expressions of RASSF1A mRNA were observed increased with the increase of the drug concentration.After treated with different concentration of 5-Aza-CdR,the expressions of RASSF1A mRNA treated with 0.5 μmol/L 5-Aza-cdR was lower than those treated with 5 and 50 μmol/L 5-Aza-cdR (t =-8.866,P =0.01 ; t =-12.256,P =0.000).However,expressions of RASSF1A mRNA treated with 5 and 50 μmol/L 5-Aza-cdR respectively showed no statistical significance (t =0.431,P =0.689).Expressions of RASSF1A protein treated with 0.5 μmol/L 5-Aza-cdR and 5 μmol/L 5-Aza-cdR didn't show statistically significant (t =-1.586,P =0.188).Conclusion Expressions of RASSF1A mRNA and protein in SKOV3 and 3AO cells were evidently enhanced.As one kind of methyltransferases inhibitors,5-Aza-CdR can inhibit ovarian cancer cell line SKOV3,3AO growth through the RASSF1A promoter methylation,and thus promote their apoptosis.
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Objective To study the application of Cell Counting Kit-8(CCK-8) in detecting the growth inhibiting effect of 5-Aza-2’-deoxycytidine on chronic myeloid leukemia cell .Methods The proliferation of K562 cells was detected by CCK-8 with different concentrations of 5-Aza-2 ’-deoxycytidine and the cell cycle and apoptosis of K 562 cells were detected after K562 treated by 50% inhibitory concentration of 5-Aza-2 ’-deoxycytidine .Results The 50% inhibitory concentration of 5-Aza-2’-deoxycytidine was 15.55nmol/L, after treated with this concentration , K562 cells showed that G2 phase arrest occurred , proliferation inhibited and apoptosis peaks appeared .Conclusion Inhibition of proliferation of K562 cells with different concentrations of 5-Aza-2’-deoxycytidine varied in a dose-dependent relationship , and 5-Aza-2’-deoxycytidine could promote apoptosis of K 562 cells.CCK-8 can be used in detecting the effect of 5-Aza-2’-deoxycytidine on chronic myeloid leukemia cells .
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Objective Tumor suppressor gene p53 can inhibit tumor cell growth, arrest cell cycle, and promote apoptosis.Howev-er, the effects of p53 on the pathogenesis of breast cancer have not been fully elucidated.The aim of this study was to explore the expression of p53 protein and the correlation with clinical pathologic features in breast cancer.Furthermore, the regulatory effects of 5-aza-2′-deoxycyti-dine on p53 in breast cancer cell line were also studied. Methods The expression of p53 protein in 80 cases of breast cancer and normal and adjacent tissue were determined by the immunohistochemical staining .The expressions of p53 mRNA and p53 protein in breast cancer cell line were determined by RT-PCR and Western blotting. Results The positive rate of p53 in breast cancer (41.25%) was higher than that in the normal and adjacent tissue (22.5%) (P0.05).The low expression of p53 both in mRNA and in protein levels were found in breast cancer cell line of MCF-7.The expres-sion of p53 increased after 5-aza-2′-deoxycytidine administration . Conclusion p53 is highly expressed in breast cancer , which may play an im-portant role in the development and progression of breast cancer. 5-aza-2′-deoxycytidine, up-regulating the p53 expression in breast cancer cell line, which provides the evidents for the development of therapeutic drugs for the patients with low expression of p53 breast cancer.
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Objective To observe the cell proliferation inhibition of DNA methyltransferase (DNMT) inhibitors decitabine (DAC) combined with daunorubicin (DNR) in human leukemia cell line HL-60.Methods The effects of DNR and DAC were examined in HL-60 cells by cell viability using MTT method,and cell death using flow cytometric (FCM).Results DAC,DNR single drug application showed their effects on cell proliferation was dependent of dose and time,the inhibition effect of combined treatment group was much clearer [inhibition ratio of 72 hours was (80.23±1.71) ％,P ＜ 0.001].The highest apoptosis rate was at 5.0 μmol/L DAC combined with 1.0 μmol/L DNR for 72 hours,which was statistic significant (F =30.199,P ＜ 0.001).Combinations of different concentrations of DAC and DNR increased expression of PTEN mRNA in concentration-dependent manner,which was significantly higher than the control group and DNR single drug group (F =578.218,P ＜ 0.001).Conclusions DAC can significantly inhibit the proliferation of HL-60 cells and induce apoptosis,synergistic effect can be observed when DAC combined with DNR.The underlying mechanism can be due to DAC demethylation effect to increase PTEN mRNA expression.
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Background and purpose:Loss or altered expression of Ras association domain family 1A gene (RASSF1A) through DNA methylation has been associated with the pathogenesis of a variety of cancers, which suggests the tumor suppressor function of this gene. This study aimed to explore the effect of DNA methyltransferase inhibitor 5-Aza-2’deoxycytidine (5-Aza-dc) on demethylation and expression of RASSF1A in cervical cancer cell lines. Methods:HPV positive cervical cancer cell lines HeLa and Caski, HPV negative cell lines HT-3 and C-33A were treated with two different concentration of 5-Aza-dc (5 μmol/L, 10 μmol/L). MSP (methylation-specific PCR) and Bisulfite genomic sequencing PCR (BGS) combined with TA clone were used to investigate methylation status of RASSF1A gene promoter and exon 1 before and after treatment of 5-Aza-dc. RASSF1A gene mRNA expression was detected by RT-PCR. Results:Two HPV positive cell lines showed hypomethylated RASSF1A promoters and expressed RASSF1A mRNA, and after treatment with 5-Aza-dc, the mRNA expression of RASSF1A did not change significantly (FHeLa=3.003, P=0.125; FCaski=0.045, P=0.956). Two HPV negative cervical cancer cell lines showed hypermethylation status of RASSF1A promoter and silenced RASSF1A. After treatment with 5-Aza-dc, demethylation occurred in the promoter region of RASSF1A gene, which subsequently induced re-expression of this gene in HT-3 and C-33A. The F test (FHT-3=18.002, P=0.03;FC-33A=17.179, P=0.03) and LSD-t test (P<0.05) demonstrated that significant difference in the expression of RASSF1A was found upon two different concentrations drug treatment.Conclusion:The methylation status of promoter and exon 1 of RASSFIA gene in HPV positive and HPV negative cervical cancer cell lines are different. The promoter hypermethylation is correlated with RASSF1A gene expression in HPV negative cervical cancer cell line HT-3 and C-33A, and plays a key role in RASSF1A silencing. 5-Aza-dc may effectively reverse the methylation status of RASSFIA gene promoter in cervical cancer HT-3 and C-33A cells and reactivate gene expression silenced by aberrant hypermethylation in a dose-dependent manner within certain extent.
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Objective: To investigate the effect of methyltransferase inhibitor 5-Aza-dC (5-aza-2'- deoxycytidine) on the expression of FANCF (Fanconi anemia complementation group F) gene in ovarian cancer OVCAR3 cells, and examine its effect on the sensitivity to chemotherapeutic drug paclitaxel in ovarian cancer in vitro , and to explore the antitumor effect of 5-Aza-dC as a new target for treatment of ovarian cancer. Methods: The ovarian cancer OVCAR3 cells (methylated FANCF gene) and A2780 cells (unmethylated FANCF gene) were treated with 5-Aza-dC. The methylation status of FANCF gene and the expression levels of FANCF mRNA and protein in OVCAR3 and A2780 cells before and after the treatment with 5-Aza-dC were detected by MSP (methylation-specific PCR), RT-PCR and Western blotting, respectively. The proliferation rate of these ovarian cancer cells was detected by MTT method, and the apoptosis rate of these cells treated with paclitaxel was measured by FCM (flow cytometry). The xenografts were induced in nude mice transplanted with OVCAR3 cells or A2780 cells. The effect of 5-Aza-dC on the growth of the xenografts in nude mice was observed. The expression of FANCF protein in the xenografts was detected by immunohistochemistry. Results: DNA promoter methylation disappears in OVCAR3 cells after treatment with 5-Aza-dC, and the expression levels of FANCF mRNA and protein were increased in vitro . The growth of OVCAR3 cells was also slowed down. The volume and the weight of OVCAR3 ovarian cancer xenografts treated with 5-Aza-dC were both significantly decreased as compared with those of the untreated xenografts in nude mice; the expression of FANCF protein in the xenografts was increased after treatment with 5-Aza-dC. These changes were not observed in A2780 ovarian cancer xenografts in nude mice. Conclusion: The methyltransferase inhibitor 5-Aza-dC may become a potential therapeutic drug in the treatment of ovarian cancer through inhibiting the proliferation of ovarian cancer cells, but it can also increase the risk of resistance to paclitaxel. © 2012 by Tumor.
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Objective: To investigate the effect of 5-aza-2'-deoxycytidine on the autophagy of human breast cancer cells, and to explore the possible mechanism. Methods: Breast cancer cells were treated with etoposide, cisplatin and 5-aza-2'-deoxycytidine. DNA damage was detected by comet assay, and the expressions of p53 and p21 proteins were examined by Western blotting. The autophagy of breast cancer cells was monitored by three methods: (1) The expression of microtubule-associated protein 1 light chain 3-II (LC3-II) was detected by Western blotting; (2) The breast cancer cells presenting autophagosome vacuoles were counted under a fluorescence microscope after staining with monodansylcadaverine (MDC), and the percentage of cells presenting autophagosome vacuoles was calculated; (3) The green fluorescent protein (GFP)-positive breast cancer cells after transfection with pEGFP-LC3 were counted under a fluorescence microscope, and the percentage of GFP-positive breast cancer cells was calculated. Results: Etoposide and cisplatin induced the DNA damage and autophagy in breast cancer cells. Compared with the untreated breast cancer cells, the comet tail length was increased (P <0.01) and the expression levels of p53, p21 and LC3-II proteins were all up-regulated in the breast cancer cells treated with etoposide and cisplatin. The 5-aza-2'-deoxycytidine could also induce the DNA damage and autophagy in breast cancer cells, and the comet tail length was increased (P <0.01), the expression levels of p53, p21 and LC3-II proteins were up-regulated, as well as the percentages of MDC-positive breast cancer cells and GFP-positive breast cancer cells were both increased (P <0.05, P <0.01). Conclusion: 5-Aza-2'- deoxycytidine can induce the autophagy of breast cancer cells, and the mechanism may be associated with DNA damage. Copyright © 2012 by TUMOR.
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Objective Imatinib mesylate (IM) is the most active agent in treating chronic myeloid leukemia (CML). 5-Aza-2-deoxycytidine (DAC) is a cytosine analogue that inhibits DNA methylation and the activity in myeloid leukemia. Therefore,we investigated combining these two drugs in human leukemia cell line K562. Methods The effects of IM and DAC was examined in K562 cells including cell viability using MTT method,cell cycle phase and cell death using flow cytometric (FCM),and the expression of bcr-abl mRNA by RT-PCR. Results Both DAC and IM resulted in time and concentration-dependent induction of cell death. DAC and IM in combination produced a greater inhibition of growth against K562 cells (F =43.947,165.580,321.193,296.101,P<0.05). The main effect and interaction between two drugs was statistically significant (F = 202.759,168.457,417.538,P <0.001) after 24 h,48 h,72 h and a greater reduction in expression of bcr-abl mRNA than either agent alone. The difference was statistically significant (F =71.981,P <0.05). The number of G1 phase cells were increased significantly when induced by single agent. 48 h incubation with IM 0.2 μmol/L alone or combined with DAC 4 μmol/L showed 6.7 %,8.4 % pre-apoptosis cells,respectively. After incubation for 48 h with DAC 4 μmol/L,the expression of mRNA were decreased by 14 %,IM 0.2 μmol/L showed 40 % reduction,and combination group were significantly depressed for the mRNA expression by 60 %. Conclusion The combination of DAC and IM showed synergistic effects on cell death in K562 cells. These data suggested that DAC used in combination with IM has clinical potential in the treatment of chronic myeloid leukemia.
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Objective:To investigate the methylation status of N-myc downstream regulated gene-1(NDRG-1) gene in breast cancer and the effects of methylation enzyme inhibitor 5-Aza-2'-deoxycytidine (5-Aza-CdR) on growth and expression of NDRG-1 mRNA in human breast cancer cell line T47D.Methods:Sensitive methylation-specific (MSP)-PCR was used to detect the methylation status in the promoter regions of NDRG-1 gene in 47 samples of breast cancer and tumor adjacent tissues and 15 cases of benign breast disease. The change in expression of the tumor suppressor gene NDRG-1 mRNA in cultured T47D cells was detected by RT-PCR before and after 5-Aza-CdR treatment. Cell proliferation was observed by MTT assay.Results:Hypermethylation frequencies of NDRG-1 gene promoter were 46.8% in breast cancer tissues and 21.3% in tumor adjacent tissues. No hypermethylation of NDRG-1 gene was observed in the tissues of breast benign disease. The growth of T47D cells was suppressed obviously after 5-Aza-CdR treatment compared with the control group. RT-PCR showed that compared with the control group, NDRG-1 mRNA expression was increased at different concentrations in 5-Aza-CdR treatment group. Conclusion:The promoter methylation status of NDRG-1 gene was significantly related with the occurrence of breast carcinoma. 5-Aza-CdR could effectively reverse the methylation of NDRG-1 gene and recover its expression, thereby inhibiting the growth of tumor cells.