• Nuclear Medicine and Molecular Imaging
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• 제41권3호
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• pp.209-217
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• 2007

목적: mdr1유전자를 표적으로 한 short hairpin RNA (shMDR)는 다약재내성을 나타내는 암세포에서 효과적으로 mdr1 유전자의 발현을 억제 할 수 있고 sodium iodide symporter (NIS)는 유전자 치료와 리포터로의 기능을 동시에 나타낼 수 있다. 이 연구에서는 사람 대장암세포(HCT15)에 shMDR과 NIS를 동시에 이입하고 Tc-99m sestamibi와 I-125 섭취를 측정하였고 doxorubicin과 I-131 치료효과도 관찰하였다. 대상 및 방법: 사람 태아 신장 세포주(Human Embryonic Kidney cells; HEK293)에 liposome 시약으로 shMDR을 이입하고 RT-PCR과 western blot으로 분석하였다. shMDR와 NIS 유전자가 발현하는 adenovirus를 만들고 HCT15 세포에 이입 후 48시간에 shMDR에 의한 Pgp의 기능 억제를 확인하기위해 Tc-99m sestamibi 섭취와 doxorubicin 세포독성을 측정하였다. 또한 NIS유전자의 기능을 확인 하기위해 I-125 섭취와 I-131 세포독성도 확인하였다. 결과: shMDR이 이입 된 HEK293 세포에서 mdr1의 mRNA와 Pgp의 발현이 각각 75%, 80% 감소하였다. NIS 유전자가 발현하는 adenovirus를 HCT15 세포에 이입하고 NIS 유전자 발현을 확인 한 결과 대조군에 비해 월등히 높게 발현하였다. Ad-shMDR 300 MOI, Ad-shMDR 300 MOI 와 Ad-NIS 10 MOI를 처리한 경우 Tc-99m sestamibi의 섭취가 대조군보다 1.5배 정도 증가하였다. HCT15 세포에 Ad-NIS 10 MOI를 감염시킨 경우 I-125 섭취가 대조군에 비해 25배 이상 증가였다. 또한 Ad-shMDR와 Ad-NIS를 동시 감염 시켰을 경우 doxorubicin의 세포 독성이 증가하여 나타났고 Ad-NIS 20 MOI를 감염시켰을 때 I-131에 의한 세포독성이 대조군보다 증가하였다. 결론: 세포에 shMDR의 이입으로 mdr1 유전자의 발현이 억제되고 Tc-99m sestamibi의 섭취와 doxorubicin의 세포독성이 증가하였으며 NIS 유전자의 이입으로 I-125의 섭취와 I-131의 세포독성이 증가하였다. 다약제내성세포에 shMDR와 NIS 유전자의 동시 이입은 doxorubicin과 방사성 옥소의 이중치료 효과를 높일 수 있을 것으로 본다.

• 한국자원식물학회지
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• 제22권3호
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• pp.273-280
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• 2009

A cDNA clone encoding a MDR-like ABC transporter protein was isolated from Brassica rapa seedlings, through rapid amplification of cDNA ends (RACE). This gene (named as Brmdr 1; GenBank accession no.: DQ296184 ) had a total length of 4222 bp with an open reading frame of 3900 bp, and encoded a predicted polypeptide of 1300 amino acids with a molecular weight of 143.1 kDa. The BrMDR1 protein shared 71.0, 62.5, 60.0 and 58.2% identity with other MDR proteins isolated from Arabidopsis thaliana (AAN28720), Coptis japonica (CjMDR), Gossypium hirsutum (GhMDR) and Triticum aestivum (TaMDR) at amino acid level, respectively. Southern blot analysis showed that Brmdr1 was a low-copy gene. Expression pattern analysis revealed that Brmdr1 constitutively expressed in the root, stem petals and stamens, but with lower expression in leaves and open flowers. The domains analysis showed that BrMDR1 protein possessed two transmembrane domains (TMDs) and two nucleotide binding domains (NBDs) arranging in "TMD1-NBD1-TMD2-NBD2" direction, which is consistent with other MDR transporters. Within NBDs three characteristic motifs common to all ABC transporters, "Walker A", "Walker B" and C motif, were found. These results indicate that BrMDR1 is a MDR-like ABC transporter protein that may be involved in the transport and accumulation of secondary metabolites.

• Archives of Pharmacal Research
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• 제29권10호
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• pp.866-873
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• 2006

When patients with cancers are treated with chemotherapeutic agents a long time, some of the cancer cells develop the multidrug resistance (MDR) phenotype. MDR cancer cells are characterized by the overexpression of multidrug resistance1 (MDR1) gene which encodes P-glycoprotein (Pgp), a surface protein of tumor cells that functions to produce an excessive efflux and thereby an insufficient intracellular concentration of chemotherapeutic agents. A variety of studies have sought potent MDR modulators to decrease MDR1 gene expression in cancer cells. Our previous study has shown that curcumin exhibits characteristics of a MDR modulator in KB-V1 multidrug-resistant cells. The aim of this study was to further investigate the effect of curcumin on MDR1 gene expression in patient leukemic cells. The leukemic cells were collected from 78 childhood leukemia patients admitted at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai, Thailand, in the period from July 2003 to February 2005. There were 61 cases of acute lymphoblastic leukemia (ALL), 14 cases of acute myeloblastic leukemia (AML), and 3 cases of chronic myelocytic leukemia (CML). There were 47 males and 31 females ranging from 1 to 15 years old. Bone marrows were collected. The leukemic cells were separated and cultured in the presence or absence of $10{\mu}M$ curcumin for 48 hours. MDR1 mRNA levels were determined by RT-PCR. It was found that curcumin reduced MDR1 gene expression in the cells from 33 patients (42%). Curcumin affected the MDR1 gene expression in 5 of 11 relapsed cases (45%), 10 of 26 cases of drug maintenance (38%), 7 of 18 cases of completed treatment (39%), and 11 of 23 cases of new patients (48%). The expression levels of MDR1 gene in leukemic patient cells as compared to that of KB-V1 cells were classified as low level (1-20%) in 5 of 20 cases (25%), medium level (21-60%) in 14 of 32 cases (44%), and high level (61-100%) in 14 of 20 cases (70%). In summary, curcumin decreased MDR1 mRNA level in patient leukemic cells, especially in high level of MDR1 gene groups. Thus, curcumin treatment may provide a lead for clinical treatment of leukemia patients in the future.

• Genomics & Informatics
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• 제16권4호
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• pp.37.1-37.3
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• 2018

Gene-gene interaction is a key factor for explaining missing heritability. Many methods have been proposed to identify gene-gene interactions. Multifactor dimensionality reduction (MDR) is a well-known method for the detection of gene-gene interactions by reduction from genotypes of single-nucleotide polymorphism combinations to a binary variable with a value of high risk or low risk. This method has been widely expanded to own a specific objective. Among those expansions, fuzzy-MDR uses the fuzzy set theory for the membership of high risk or low risk and increases the detection rates of gene-gene interactions. Fuzzy-MDR is expanded by a maximum likelihood estimator as a new membership function in empirical fuzzy MDR (EFMDR). However, EFMDR is relatively slow, because it is implemented by R script language. Therefore, in this study, we implemented EFMDR using RCPP ($c^{{+}{+}}$ package) for faster executions. Our implementation for faster EFMDR, called EMMDR-Fast, is about 800 times faster than EFMDR written by R script only.

• 대한골관절종양학회지
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• 제3권1호
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• pp.9-17
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• 1997

Resistance to combination chemotherapy remains challenge in the treatment of osteosarcoma. One of the mechanisms of multiple drug resistance is an increased expression of the multidrug resistance gene(mdr1). Expression of the P-glycoprotein(mdr-1 gene product) was studied immunohistochemically and the mdr-1 gene by in situ hybridization in 33 osteosarcomas relating to various prognostic factors. Thirty cases out of 33 osteosarcomas(90.9%) showed positive cytoplasmic reactions with P-glycoprotein and nineteen instances(57.6%) were strong positive(2+). The older(>20 years) and female patients revealed more intense immunohistochemical reactions rather than those of the younger and male patients. Osteoblastic and chondroblastic osteosarcomas revealed more strong immunohistochemical reactions compared to fibroblastic types. There were no significant staining differences between the type of bony involvement, Broder's grade and the presence of necrosis. On follow-up, the mean survival rate was decreased in the strong positive group, however, this was not statistically significant. In situ hybridization for mdr-1 gene revealed positive signals in 22 cases out of 29 osteosarcomas(75.9%). Chemotherapy was done in 15 cases out of 28 patients(53.6%). The results of immunohistochemistry and in situ hybridization were not correlated with the protocols for chemotherapy. However, this result should be confirmed by a larger scale study about mdr1 mRNA expression.

• Journal of Pharmaceutical Investigation
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• 제37권5호
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• pp.297-303
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• 2007

The purposes of this study were to clarify the involvement of P-glycoprotein (P-gp) in the efflux of levosulpiride in knockout mice that lack the mdr1a1b gene and to evaluate the relationship between the genetic polymorphisms in MDR1 gene (exon 21) and levosulpiride disposition in healthy Korean subjects. After oral administration ($10\;{\mu}g/g$) of levosulpiride to mdr1a/1b(-/-) and wild-type mice, plasma and brain samples were obtained at 45 min. We also investigated the genotype for MDR1 (exon 21) gene in humans using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. A single oral dose of 25 mg levosulpiride was administered to 58 healthy subjects, who were based on the MDR1 genotype for the G2677T SNP. Blood samples were taken up to 36 hr after dosing. The concentrations of levosulpiride in mouse plasma and brain were statistically significant difference between the two animal groups (P<0.05). In addition, the average brain-to-plasma concentration ratio (Kp) of levosulpiride was 3.4-fold (P<0.01) higher in the mdr1a/1b(-/-) mice compared with the wild-type mice. We also found that the values of $AUC_{0-{\infty}$, partial AUC ($AUC_{0-4h}$) and $C_{max}$ were significantly different between homozygous 2677TT subjects and the subjects with at least one wild-type allele (GG and GT subjects, P=0.012 for $AUC_{0-{\infty}$; P=0.008 for $AUC_{0-4h}$; P=0.038 for $C_{max}$). The results confirm that levosulpiride is a P-gp substrate in vivo, and clearly demonstrate the effect of SNP 2677G>T in exon 21 of the MDR1 gene on levosulpiride disposition.

• Archives of Pharmacal Research
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• 제29권12호
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• pp.1132-1139
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• 2006

Single nucleotide polymorph isms (SNPs) in the MDR1 gene that are responsible for drug efflux can cause toxicity. Therefore, this study determined the SNPs of the Korean MDR1 gene, and analyzed the haplotypes and a linkage disequilibrium (LD) of the SNPs determined. The frequency of 9 SNPs from the MDR1 gene was determined by PCR-RFLP analyses of 100 to 500 healthy individuals. The frequcies of the SNPs were C3435T (47.7%), G2677T (37.6%), G2677A (4.4%), T1236C (21.7%), T129C (8%), A2956G (2.5%), T307C (1.5%), A41aG (9.2%), C145G (0%), and G4030C (0%). Analyses of the haplotype structure and an estimation of the LD of the combined polymorph isms demonstrated that the frequency of the 1236T-2677G-3435T haplotype is much higher in Koreans (14.1%) than in Chinese and western black Africans and the C3435T SNP in Koreans appears to have LD with T129C in Koreans for the first time. These results provide insight into the genetic variation of MDR1 in Koreans, and demonstrated the possibility of a new LD in this gene.

• ETRI Journal
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• 제38권1호
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• pp.206-215
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• 2016

The detection of gene-gene interactions during genetic studies of common human diseases is important, and the technique of multifactor dimensionality reduction (MDR) has been widely applied to this end. However, this technique is not free from the "curse of dimensionality" -that is, it works well for two- or three-way interactions but requires a long execution time and extensive computing resources to detect, for example, a 10-way interaction. Here, we propose a boosting method to reduce MDR execution time. With the use of pre-evaluation measurements, gene sets with low levels of interaction can be removed prior to the application of MDR. Thus, the problem space is decreased and considerable time can be saved in the execution of MDR.

• Asian Pacific Journal of Cancer Prevention
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• 제13권8호
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• pp.3631-3636
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• 2012

Objective: To determine whether silence of $PKC-{\alpha}$ expression by small interference RNA (siRNA) might regulate MDR1 expression and reverse chemoresistance of ovarian cancer. Methods: We measured gene and protein expression of MDR1 and $PKC-{\alpha}$ in ovarian cancer cells and assessed their correlation with cell drug resistance. We also examined whether blocking $PKC-{\alpha}$ by RNA interference (RNAi) affected MDR1 expression and reversed drug resistance in drug sensitivity tests. Results: The drug resistance cell lines, OV1228/DDP and OV1228/Taxol, had higher gene and protein expression of MDR1 and $PKC-{\alpha}$ than their counterpart sensitive cell line, OV1228. SiRNA depressed $PKC-{\alpha}$ gene protein expression, as well as MDR1 and protein expression and improved the drug sensitivity in OV1228/DDP and OV1228/Taxol cells. Conclusion: These results indicated that decreasing $PKC-{\alpha}$ expression with siRNA might be an effective method to improve drug sensitivity in drug resistant cells with elevated levels of $PKC-{\alpha}$ and MDR1. A new siRNA-based therapeutic strategy targeting $PKC-{\alpha}$ gene could be designed to overcome the chemoresistance of ovarian cancer.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.3213-3217
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• 2013

Background: P-glycoprotein (Pgp), encoded by the multidrug resistance 1 (MDR1) gene, is an efflux transporter which plays an important role in pharmacokinetics. The current preliminary study was designed to determine associations between a germ-line polymorphism in the MDR1 gene with differentiated thyroid carcinoma (DTC). Materials and Methods: In the current case-control study, 60 differentiated thyroid cancers (DTC)- 45 papillary TC (PTC), 9 follicular TC(FTC) and 6 well-differentiated tumors of uncertain malignant potential (WDT-UMP) were examined. Results were compared to a healthy control group (n=58) from the same population. Genomic DNA was extracted from peripheral blood with EDTA and the target gene was genotyped by real-time PCR. Results: Carriers of the variant allele of MDR1 exon 26 polymorphism were at 2.8-fold higher risk of DTC than the control group (odds ratio [OR]: 0.3805, 95% confidence interval [Cl]: 0.1597-0.9065 (p> 0.046). Conclusions: Presented results suggest that the MDR1 3435TT genotype might influence risk of development of DTC and that the CC genotype might be linked to a poor prognosis. Large-scale studies are now needed to validate this association.