Association of MDR1 gene polymorphisms with refractory epilepsy in children / 中华医学遗传学杂志

Objective@#To assess the association of single nucleotide polymorphisms of multidrug resistance gene 1 (MDR1) with refractory epilepsy in children.@*Methods@#Peripheral blood samples were collected from 200 children with epilepsy and 100 healthy controls. Genomic DNA was extracted and subjected to PCR amplification, agarose gel electrophoresis and target site sequencing. Genotypes of rs1922242, rs2235048, rs10808072, rs868755 and rs1202184 loci of the MDR1 gene were analyzed.@*Results@#No significant difference was found in genotypic distribution and allelic frequencies of the rs1922242, rs2235048, rs10808072 and rs868755 loci between the drug-resistant and drug-sensitive groups. For the rs1202184 locus, a significant difference in genotypic distribution was found (P = 0.008). No significant difference was found in the frequencies of various haplotypes between the two groups.@*Conclusion@#Genotypes of the rs1202184 locus of the MDR1 gene are associated with refractory epilepsy in children, for which the AA genotype plays a dominant role.

Development of an oligonucleotide microarray for simultaneous detection of two canine MDR1 genotypes and association between genotypes and chemotherapy side effects

Canine MDR1 gene mutations produce translated P-glycoprotein, an active drug efflux transporter, resulting in dysfunction or over-expression. The 4-base deletion at exon 4 of MDR1 at nucleotide position 230 (nt230[del4]) in exon 4 makes P-glycoprotein lose function, leading to drug accumulation and toxicity. The G allele of the c.-6-180T>G variation in intron 1 of MDR1 (single nucleotide polymorphism [SNP] 180) causes P-glycoprotein over-expression, making epileptic dogs resistant to phenobarbital treatment. Both of these mutations are reported to be common in collies. This study develops a more efficient method to detect these two mutations simultaneously, and clarifies the genotype association with the side effects of chemotherapy. Genotype distribution in Taiwan was also investigated. An oligonucleotide microarray was successfully developed for the detection of both genotypes and was applied to clinical samples. No 4-base deletion mutant allele was detected in dogs in Taiwan. However, the G allele variation of SNP 180 was spread across all dog breeds, not only in collies. The chemotherapy adverse effect percentages of the SNP 180 T/T, T/G, and G/G genotypes were 16.7%, 6.3%, and 0%, respectively. This study describes an efficient way for MDR1 gene mutation detection, clarifying genotype distribution, and the association with chemotherapy.

Effect of CDR1/CDR2 or MDR1 genes overexpression on oxidative stress in Candida albicans / 中国人兽共患病学报

To investigate the effect of CDR1/CDR2 or MDR1 genes overexpression on oxidative stress in Candida albicans,we evaluated the effect of H2O2 on cell viability in C.albicans overexpressing genes CDR1 /CDR2 or MDR1 and their parent strains.After establishing an oxidative stress model with H2O2,we detected reactive oxygen species (ROS),mitochondrial membrane potential (Δψm) and the expression of oxidative stress response-related genes (CAP1 and GRP2) and ROS clearance related-genes (SOD2 and SOD5).The results showed that C.albicans growth were inhibited by 100％ after the treatment of 5 mmol/L H2O2.HeO2 caused more ROS accumulation and Δψm reduction in parent strains than in CDR1/CDR2 or MDR1 genes overexpressed strains (P＜0.05).Compared to parent strains,the up-regulated expression of CAP1 and GRP2 were relatively less in CDR1/CDR2 or MDR1 genes overexpressed strains,moreover,the down-regulated expression of SOD2 and SOD5 were also relatively less in CDR1/CDR2 or MDR1 genes overexpressed strains (P＜0.05).In conclusion,the overexpression of CDR1/CDR2 and MDR1 genes could reduce the oxidative stress response and enhance the adaptability of C.albicans to oxidative stress.

Research the Expression of MDR1 Genes in Vaginal Candida Albicans Resistance to Azole Agents / 现代检验医学杂志

Objective To investigate the expression levels of MDR1 gene from azole resistant strains in vaginal Candidaalbi-cans.Methods 60 strains of Candida albicans from recurrent vagintis patients were collected and identified by CHROM agar from Aug.2011 to Aug.2012.The drug resistance was detected by disk diffusion method.According to the result of drug sensitivity test,the strains were diveded into four groups:sensitive group moderately susceptible or resistant to flucon-azole group moderately susceptible or resistant to detoconazole group and moderately susceptible or resistant to miconazole group.Each group was selected 12 strains randomly.The expression of the MDR1 gene in these 48 strains were detected by real-time RT-PCR and analysed the datas by t test statistics.Results There were 22 sensitive strains,26 strains of moder-ately susceptible or resistant to detoconazole,12 strains of moderately susceptible or resistant to fluconazole and 38 strains of moderately susceptible or resistant to miconazole in 60 strains of Candidaalbicans.The relative expression of MDR1 gene in sensitive group was 0.41±0.47,in moderately susceptible or resistant to detoconazole group fluconazole group and micon-azole group were 3.32±4.46,2.27±3.05 and 0.9±0.81 respectively.Compared with the sensitive group,t values of mod-erately susceptible or resistant to detoconazole group,fluconazole group and miconazole group were-2.177,-2.130 and-2.094.The expression level of MDR1 gene had no statistical significance between the sensitive strains and moderately sus-ceptible or resistant strains(P>0.05).Conclution The relationship between MDR1 expression and the resistance to azole agents in vaginal Candida albicans requires further study.

Selective cyclooxygenase-2 inhibitor celecoxib could sensitize B-cell-originated lymphoma cell lines ;to epirubicin via down-regulation of MDR-1 mRNA and Bcl-2 mRNA expression / 中国癌症杂志

Background and purpose: It has been demonstrated that cyclooxygenase-2 (COX-2) is over-expressed in some subtypes of non-Hodgkin’s lymphoma (NHL), and COX-2 correlates with the expression of P-glycoprotein and Bcl-2, which may contribute to chemotherapy-resistance in NHL. The purpose of this study was to investigate the expression of COX-2 in B-cell lymphoma cell lines and the potential mechanisms of celecoxib, a selective COX-2 inhibitor, to sensitize lymphoma cell lines to epirubicin. Methods: Quantitative fluorescent real-time poly-chain-reaction (qRT-PCR) and Western blot were employed to determine the expression of COX-2 in Raji, Jeko-1 and Namalwa cell lines, as well as in peripheral blood B cells from normal controls. Cell lines were treated with celecoxib at gradient concentrations, followed by the detection of cell viabilities by cell counting kit-8 (CCK-8).Meanwhile, the changes in expression of MDR-1 mRNA and Bcl-2 mRNA before and after celecoxib treatment were determined by qRT-PCR. Raji cells were treated with epirubicin alone or in combination with gradient concentrations of celecoxib for 72 h, then CCK-8 was used to analyze whether celecoxib sensitize Raji cells to epirubicin. Results:Neither lymphoma cell lines nor normal B cells expressed detectable COX-2 in this study. Celecoxib inhibited the proliferation of the 3 lymphoma cell lines, and the mRNA expressions of MDR-1 and Bcl-2 were decreased by celecoxib in a concentration-dependent manner, except for that MDR-1 was undetectable in Jeko-1 cells. In addition, celecoxib sensitized Raji cells to epirubicin, indicating a synergistic anti-tumor effect between the two agents. Conclusion:Selective COX-2 inhibitor celecoxib down-regulates the expressions of MDR-1 mRNA and Bcl-2 mRNA in B-cell-originated lymphoma cell lines, and sensitizes Raji cells to epirubicin.

Association study between the MDR1 gene and clinical characteristics in schizophrenia

Objective: Schizophrenia is a complex psychiatric disorder, characterized by disturbed patterns of thought and affecting 0.3-2.0% of the world population. Previously, the multidrug resistance 1 (MDR1) gene has been associated with schizophrenia in treatment response studies in psychotic patients. The aim of this study was to determine the association between MDR1 gene polymorphisms and clinical characteristics in patients with schizophrenia. Methods: Positive and negative symptoms of schizophrenia were assessed with the Scale for the Assessment of Negative Symptoms (SANS) and the Scale for the Assessment of Positive Symptoms (SAPS) in 158 Mexican patients with schizophrenia. Analyses of MDR1 gene polymorphisms were performed using TaqMan technology. A multivariate ANOVA was performed with MDR1 polymorphisms and gender as independent variables. Results: Males with the G/G genotype of MDR1 rs2032582 presented significantly higher levels of delusions (p = 0.02). When comparing female vs. male groups, the difference was statistically significant (p = 0.0003). Analyses of the MDR1 gene rs1045642 variant showed no significant differences. Conclusion: Our findings suggest that male carriers of the G allele of variant rs2032582 exhibit greater severity of delusions; however, these results should be taken as preliminary, and replication studies in other populations of different ethnic origins are required to confirm these findings. .

CIAPIN1 gene silencing enhances chemosensitivity in a drug-resistant animal model in vivo

Overexpression of cytokine-induced apoptosis inhibitor 1 (CIAPIN1) contributes to multidrug resistance (MDR) in breast cancer. This study aimed to evaluate the potential of CIAPIN1 gene silencing by RNA interference (RNAi) as a treatment for drug-resistant breast cancer and to investigate the effect of CIAPIN1 on the drug resistance of breast cancer in vivo. We used lentivirus-vector-based RNAi to knock down CIAPIN1 in nude mice bearing MDR breast cancer tumors and found that lentivirus-vector-mediated silencing of CIAPIN1 could efficiently and significantly inhibit tumor growth when combined with chemotherapy in vivo. Furthermore, Western blot analysis showed that both CIAPIN1 and P-glycoprotein expression were efficiently downregulated, and P53 was upregulated, after RNAi. Therefore, we concluded that lentivirus-vector-mediated RNAi targeting of CIAPIN1 is a potential approach to reverse MDR of breast cancer. In addition, CIAPIN1 may participate in MDR of breast cancer by regulating P-glycoprotein and P53 expression.

Correlation of multidrug resistance genes and clinical risk factors with glucocorticoid response in patients with inflammatory bowel disease / 中华消化杂志

Objective To investigate the correlation of multidrug resistance gene 1 (MDR1),NR3C1 gene polymorphisms and clinical risk factors with efficacy,dependence,and resistance of glucocorticoid (GC) in patients with inflammatory bowel disease (IBD).Methods Anti coagulation blood samples of 196 healthy controls and 105 IBD patients received GC therapy were collected.There were 62 ulcerative colitis (UC) and 43 Crohn's disease (CD) in the IBD patients.The number of GC sensitive,GC dependent and GC resistant of UC patients were 36,13 and 13,respectively,and those of CD patients were 24,11 and eight.GC refractoriness included GC dependence and resistance.The genotype of MDR1 C3435T and NR3C1 Bcl Ⅰ of all the subjects was detected by the restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR).The correlation between each genotype frequency,clinical features of patients with IBD and the efficacy of GC treatment was analyzed by Chisquare test,Fisher exact probability method or t test.Results Among UC patients,the disease course of GC refractory group and GC resistant group was longer than that of GC sensitive group ((6.660±1.523)years,(6.500±1.111) yearsvs (3.350±0.697) years,t=2.211,P=0.031; t=2.930,P=0.005).The serum level of C reaction protein (CRP) of GC refractory group was higher than that of GC sensitive group ((47.628±13.913) mg/Lvs (16.854±4.121) mg/L,t=2.121,P=0.047).The chronic relapse type was more common in GC refractory UC patients (Fisher exact probability method,P=0.035),and severe patients were more common in UC with GC resistance (Fisher exact probability method,P=0.021).The white blood cell count of GC resistant and GC refractory CD patient was lower than that of GC sensitive CD patients ((5.710 ± 0.604) ×109/L,(5.878±0.405) × 109/L vs (7.814 ±0.670) × 109/L,t=2.334,P=0.028; t=2.045,P=0.018).Patients with extraqntestinal manifestations was more common in CD with GC resistance (Fisher exact probability method,P=0.035).There was no statistically significant difference in the frequencies of MDR1 C3435T,NR3C1 Bcl Ⅰ genotypes,allelic genes and gene carrier among control group and GC sensitive dependent and resistant group of IBD patients.However,the frequency of MDR1 C3435T gene carrier was significantly different between GC sensitive group and GC refractory group,especially between GC sensitive group and GC resistance group (68.33％ vs 48.89％,x2 =4.051,P=0.044; 68.33％ vs 42.86％,x2 =4.274,P =0.039).Conclusions GC sensitivity of IBD patients with MDR1 C3435T loci T gene carrier was higher than that of IBD patients without T gene carrier.NR3C1 gene polymorphisms was not related with GC resistance and GC dependence.Compared with GC sensitive IBD patients,in GC resistant and GC dependent IBD pantient UC patients with long disease course,chronic relapse type,severe type,high level of CRP and CD patients with low white blood cell count and extra-intestinal manifestations were more common.

Frequency of the mdr-1 C>T gene polymorphism in patients with COPD

BACKGROUND AND AIM: The multi-drug resistant-1 (MDR-1) gene is located on human chromosome 7 and encodes a glycosylated membrane protein that is a member of the ATP-binding cassette transporters superfamily. The aim of the study was to reveal the role of the C3435T MDR-1 gene polymorphism in chronic obstructive pulmonary disease. METHOD: DNA samples from 41 patients with chronic obstructive pulmonary disease and 50 healthy control participants were used to compare MDR-1 gene profiles. Genotyping assays were performed using the StripAssay technique that is based on reverse-hybridization. RESULTS: The T allele polymorphism in the MDR-1 gene located at position 3435 in exon 26 was shown to correlate with chronic obstructive pulmonary disease. CONCLUSION: These preliminary results suggest that the T allele polymorphism of the MDR-1 gene is associated with chronic obstructive pulmonary disease.

Mechanism of synergistic antitumor effects of EBB and doxorubicin on multidrug resistant MCF-7/ADR / 中国药理学通报

Aim To study the mechanism of synergistic antitumor of EBB and doxorubicin in doxorubicin-resistant MCF-7/ADR breast carcinoma cells.Methods The antitumor activity of doxorubiein alone and its combination with EBB were measured by MTT assay in MCF-7/ADR and MCF-7cells. The rate of doxorubicin-induced apoptosis and the protein and mRNA levels of P-glycoprotein(P-gp) were determined in MCF-7/ADR treated with EBB by flow cytometry (FACS), respectively.Laser scanning confocal microscopy was used to detect the intracellular accumulation of drug in EBB-treated MCF-7 and MCF-7/ADR cells.Results EBB had antitumor effects for MCF-7 and MCF-7/ADR.It could potentiate the antitumor effect of dororubicin with CDI of 0.73 and 0.49 for MCF-7 and MCF-7/ADR,respectively.EBB and doxorubicin acted synergistically in elevating apoptosis of MCF-7/ADR and downregulating the expression of P-gp in a dose-dependent manner in MCF-7/ADR.EBB restored the intracellular accumulation of doxorubicin in MCF-7/ADR cells in a dose-dependent manner.After pretreatment with EBB for 24 h and 48 h,the intracellular accumulation of doxorubicin and Rh123 was obviousely restored in MCF-7/ADR cells compared with control in a time-dependent manner.Conclusion EBB is a potential agent which has strong inhibitory effect on both multidrug resistant cells and their parental cells.EBB can significantly potentiate the antitumor effects of dororubicin in MCF-7/ADR cells by blocking the function of P-glycoprotein and inhibiting the expression of P-glycoprotein.

Chitosan/pshRNA Plasmid Nanoparticles Targeting MDR1 Gene Reverse Paclitaxel Resistance in Ovarian Cancer Cells / 华中科技大学学报（医学）（英德文版）

In order to investigate the effect of chitosan/pshR.NA plasmid nanoparticles targeting MDRI genes on the resistance of A2780/TS cells to paclitaxel,chitosan/pshRNA plasmid nanoparticles were synthesized by means of a complex coacervation technique and transfected into A2780/TS cells.The cells transfected with MDR1-targeted chitosan/pshRNA plasmid nanoparticles were experimental cells and the cells transfected with chitosan/pGPU6/GFP/Neo no-load plasmid nanoparticles served as negative control cells.Morphological features of the nanoparticles were observed under transmission electron microscope (TEM).MDR1 mRNA expression was assessed by RT-PCR.Half-inhibitory concentration (IC50) of paclitaxel for A2780/TS cells was determined by MTT method.TEM showed that the nanoparticles were round-shaped,smooth in surface and the diameters varied from 80 to 120 nm.The MDR1 mRNA in the transfected cells was significantly decreased by 17.6%,27.8% and 52.6% on the post-transfection day 2,4 and 7 when compared with that in A2780/TS cells control (P<0.05).MTT assay revealed that the relative reversal efficiency was increased over time and was 29.6%,51.2% and 61.3% respectively in the transfected cells 2,4,7 days after transfection and IC50 (0.197±0.003,0.144±0.001,0.120±0.004) were decreased with difference being significant when compared with that in A2780/TS (0.269±0.003) cells control (P<0.05).It was concluded that chitosan/pshRNA plasmid nanoparticles targeting MDR1 can effectively reverse the paclitaxel resistance in A2780/TS cells in a time-dependent manner.

Research on the effects and side effects of the over-dose chemotherapy to VX2 hepatocarcinoma rabbits with mdr1 gene transferring bone marrow transplantation / 重庆医科大学学报

Objective:In the study,multidrug resistance gene 1(mdr1) was transferred into the bone marrow mononuclear cells which were autotransplanted into rabbits with VX2 hepatocarcinoma.In chemotherapy experiment with adriamycin,the bone marrow protection of mdr1 gene,curative effects and side effects to heart of over dosage chemotherapy were observed.Methods: The bone marrow mononuclear cells transferred with mdr1 gene were autotransplanted into rabbits with VX2 hepatocarcinoma.After chemotherapy with adriamycin,the peripheral white blood cells count,the growth and metastasis of VX2 hepatocarcinoma and cardiac function were detected.Meanwhile,the bone marrow protection of mdr1 gene,the curative effects to VX2 hepatocarcinoma and lesions to heart of over-dosage chemotherapy were evaluated.Results:The mdr1 gene was implanted into the bone marrow after the mdr1-transferred bone marrow mononuclear cells had been autotransplanted into rabbits with VX2 hepatocarcinoma.After over-dose chemotherapy with adriamycin,the rabbits in mdr1-transferring group could be survival after treated with 3-fold dosage chemotherapy,and the white blood cell count in peripheral blood was(4.26?1.03)?109/L.Meanwhile,the tumor cells were killed effectively,and the survival time were improved compare to that of control group(P

Relation among the Tests and Comparison of Positivity of Tests for Multi-Drug Resistance in Newly Diagnosed Acute Leukemia / 대한진단검사의학회지

BACKGROUND: The expression of multi-drug resistance (MDR) in acute leukemia was known to decrease the outcome of chemotherapy and to increase the rate of relapse. Of the mechanism of MDR, the most well known is P-glycoprotein (P-gp) encoded by the mdr1 gene. There are MDR genes, P-gp tests and drug efflux function tests for the clinical measurement of MDR. To assess the clinical usefulness and MDR expression status in acute leukemia, MDR tests were performed. METHODS: MDR expression was assessed by MDR1 mRNA RT-PCR and flow cytometry measuring P-gp and daunorubicin (DNR) efflux in 77 patients with newly diagnosed acute leukemia (AL) including 48 acute myeloid leukemia (AML), 16 acute lymphoblastic leukemia (ALL) and 13 acute mixed-lineage leukemia (AMLL). The CD34 surface-marker study was also done by flow cytometry. The result of chemotherapy was evaluated by the percentage of remnant bone marrow (BM) blasts. RESULTS: The positivity of MDR1 mRNA was 57.1% (44/77) in AL, 61.5% (8/13) in AMLL, 60.4% (29/48) in AML, and 43.8% (7/16) in ALL. The positivity of P-gp expression was 36.5% (27/74) in AL and 100% in AML. The positivity of the DNR efflux test was 30.1% (22/73) in AL, 40.0% (18/45) in AML, 23.1% (3/13) in AMLL, and 6.7% (1/15) in ALL. There was a significant correlation between MDR1 mRNA and P-gp expression and between MDR1 mRNA and CD34 expression in AML. There was a significant correlation between the percentages of residual blast cells in BM and P-gp expression (P=0.039, r=0.312). CONCLUSIONS: It can be clinically useful to perform the mdr1 gene and P-gp test simultaneously both in newly diagnosed acute leukemia patients. The effectiveness of tests for MDR can be helpful to predict the outcome of chemotherapy.

Study on the Relationship Between MDR1 Gene Expression in Liver Cell and Cholesterol Calculus in Gallbladder / 中国普外基础与临床杂志

Objective To explore the relationship between the expression of MDR1 gene in liver cell and the formation of cholesterol calculus in gallbladder.Methods The mRNA expression level of MDR1 gene in liver cell of the cholesterol calculus group and the normal control group were measured through reverse transcriptionpolymerase chain reaction (RT-PCR), and microglobulin ?_2 was used as internal contrast.Results The MDR1 mRNA expression level of the cholesterol calculus group was lower than that of the normal control group(1.30?0.19 vs 2.25?(0.28), P

IMPACT OF FRACTIONED IR RADIATION ON TOTAL RNA AND MDR_1 GENE OF NCI-H446 CELL LINE / 解放军医学杂志

To study the effects of fractioned ir radiation on the total RNA and MDR 1 mRNA of NCI H 446 small cell lung cancer cell line, NCI H446 cells in the period of exponential growth were exposed to 60 Co ? radiation at 2 Gy/fraction, 2 fraction/week, with the cumulative dose of 50 Gy by 25 fractions. The total RNA of the cells of the irradiated group and control group were extracted by the acid guanidine thiocyanate phenol chloroform method and the amount of the expression of MDR 1 mRNA was assessed by qualitative RT PCR assays. Under the conditions of same cell number and volume, in cells of the control group, the concentration of the total RNA was 25 9 ?g/ml and the ratio of MDR 1 DNA/? actinDNA was 1 078, whereas in cells of the irradiation group, the corresponding values were 16 6 ?g/ml and 1 338, respectively. It is concluded that, for the NCI H446 small cell lung cancer cell line, a high dose accumulated during fractioned irradiation can inhibit the synthesis of its total RNA and enhance the expression of its MDR 1 gene at the same time.

Expression and clinical significance of MDR_1 / P-gp,C-erbB-2 in breast cancer / 中国癌症杂志

Purpose:To detect the expression of MDR 1 / P-gp,C-erbB-2 in breast cancer and study the correlation between MDR 1 /P-gp and C-erbB-2. Methods:Expression of MDR 1 gene was measured with the flu orogenic quantitative RT-PCR method in 57 cases of breast cancer and 20 cases o f control group (including 10 cases of benign breast lesions and 10 cases of adj acent breast tissues). In addition, immunohistochemical analyses was used to det ect the expression of P-gp and C-erbB-2 protein in the above mentioned tissu es. Results:The amplification rate of MDR 1 gene and the expre ssion of P-gp protein in breast cancer group was 50.88% (29/57) and 42.11% (24/ 57), which had a significient difference as compared to the control group. The a mplification of MDR 1 gene were higher than the expression of P-gp protein ,there was close correlation between them but not complete correspondence.The p ositive rate was 28.07%(16/57) in detecting the overexpression of C-erbB-2 pro tein in breast cancer group, nevertheless, no positive case was found in the con trol group. The expression of MDR 1/P-gp was also correlated with the over expression of C-erbB-2. Conclusions:Multidrug resistance gene1(MDR 1)and protoonco gene C-erbB-2 were co-expressed in breast cancer,and their expression were po sitively related. The expression of above mentioned two genes have a relationshi p with multidrug resistance in breast cancer.

The Frequency and Clinical Significance of Multidrug Resistance-1 (MDR-1) Gene Expression in Acute Myeloid Leukemia / 대한혈액학회지

BACKGROUND: The expression of the multidrug resistance-1 (MDR-1) gene which encodes p-glycoprotein, is recognized as a biological mechanism possibly contributing to treatment failure in patients with acute myeloid leukemia (AML). Recent studies indicate its association with poor risk factors such as cytogenetic pattern and surface phenotype of blasts. We analyzed the role of MDR-1 gene expression in 36 chemo-naive AML patients. METHODS: In 36 patients, clinical data were reviewed and compared to MDR-1 gene expression, immunophenotyping results on CD7 & CD34, cytogenetic pattern and other suggestive prognostic factors. RESULTS: Median follow-up period was 150 days. The MDR-1 gene expression was observed in 19 out of 36 patients (52.8%). Significant correlation between MDR-1 gene and CD7 & CD34 expression was found. Sixteen out of 17 (94.1%) MDR-1 negative patients harbored favorable cytogenetic patterns, where as 11 out of 19 (57.9%) MDR-1 positive patients had favorable cytogenetic patterns. MDR-1 gene expression was not correlated to disease free survival (DFS), nor overall survival (OS) statistically although it has shown significant correlation to complete remission (CR) rate (P =0.001). CONCLUSION: We found that lack of MDR-1 gene expression was exclusively associated to favorable cytogenetic patterns in our study. In order to clarify the relationship between the role of MDR-1 gene and clinical outcome or other prognostic features, including cytogenetic pattern, further larger studies would be necessary.

Expression and clinical studies on FLK-1,LRP and MDR1 in lung cancer patients / 中国癌症杂志

Purpose:To investigate the effect of Flk-1、LR P and MDR1 genes in the carcinogenesis and development of lung cancer. Methods:The expression of Flk-1、LRP and MDR1 geneproteins in primary lung tumors were studied immunohistochemically. Results:of the 70 lung cancers, 29 cases (49.2%) were positive for MDR1 expression in NSCLCs and 2cases (18.2%) in small cell lung carcinoma(S CLC); 41cases (69.5%)had overexpression of LRP in NSCLCs and 3cases (27.3%) in S CLCs, there was a statistically significant correlation (P

siRNAs silence expression of mdr1 gene and its role in reversing drug-resistance in K562/ADM cells / 中国癌症杂志

Background and purpose:Drug-resistance is the main obstacle in terms of efficacy of chemotherapy for leukemia, RNA interference(RNAi) strategy possesses the characteristics of specilization, high-efficiency and low-toxicity, and can effectively and specifically inhibit the overexpression of given gene. This study was designed to investigate the effect of small interfering RNA (siRNA) on expression of mdr1 gene and drug-resistance in multidrug-resistant human leukemia K562/ADM cell.Methods:Human multidrug-resistant leukemia cell line K562/ADM over-expressing mdr1 gene was used as the target cells, Two siRNAs (si-mdr1-1 and si-mdr1-2) targeted mdr1 gene were chemically synthesized and transfected into K562/ADM cells. Expression of mdr1 mRNA was determined by RT-PCR, P-glycoprotein (P-gp) expression was measured using flow cytometry (FCM), and the sensitivity of K562/ADM cells to adriamycin was assessed with a MTT colorimetric assay.Results:Two siRNAs (si-mdr1-1 and si-mdr1-2) specially designed in this study could markedly down-regulate the expression of mdr1 mRNA and its product P-gp in K562/ADM cells. After cells transfected with si-mdr1-1 or si-mdr1-2 for 24h and 48h, the inhibition of mdr1 mRNA expression in the cells for si-mdr1-1 was 55.5% and 22.5%; and for si-mdr1-2, 16.0% and 57.6%, respectively. Treated with siRNA for 72h, the expression intensity of P-gp in the two transfected cell lines decreased 74% and 85%, respectively. Both si-mdr1-1 and si-mdr1-2 significantly enhanced the sensitivity of K562/ADM cells to adriamycin and reversed their drug-resistance, the reversal efficiency was 2.52-folds and 1.96-folds, respectively.Conclusions:The siRNA could effectively and specifically silence the expression of mdr1 gene and overcome the drug-resistance mediated by P-gp in K562/ADM cells.

Experiment of the effect and safety of mdr1 gene transferring into k562 cells / 重庆医科大学学报

Objective:To transfer full-length human mdrlcDNA into K562 cells and assess the feasibility and safety in vitro.Methods:PA317 cells were transducted via a virus vector,pHaMDR1/A,containing full-length human mdr1cDNA by calcium phosphate precipitation.The K562 cells were infected with the virus supernatant.The transfection rate was determined by using CFU selection,FACS and SP immunohistochemical methods respectively.The foreign Pgp function was tested by MTT assay and DNR exclusion with FACS analysis .The cellular cycle and the expression of bcl-2 and c-myc gene were detected by using CFU sclcction,FACS and SP immunohistochemical mcthods respcctively.The forcign Pgp function was tested by MTT assay and DNR exclusion with FACS analysis.The cellular cycle and the expression of bcl-2 and c-myc gene were detected by using PI via FCM and SP stain respectively.These data were analyzed with statistic graph and T-test for match pairs.Results:①The highest transfection rate of K562/MDR6-18 cells were 34%,even up to 84% after colchicine selection.②The exogenous Pgp expression of K562/MDR6-18 cells lasted for more than 4 months with a slow decrease after 10 generations.③The exogenous Pgp got an exclusive pump function.④K562/MDR6-18 cells appeared 1.46-2.22 times cross multidrug resistance phenotype.⑤K562/MDR6-18 cellular proliferation showed a mild,short,restored change.There was no abnormal apoptosis or proliferation.Conclusions:It implies a feasible,attractive and safe way that mdr1 gene transfers into target cells to get exogenous effective MDR.They also provide the basic protocol for using mdr1 gene modifying bone marrow transplantation against the myelosuppressive effects of anticancer drugs.