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  1. Fulltext ABCC5, a gene that influences the anterior chamber depth, is associated with primary angle closure glaucoma
    Nongpiur ME, Khor CC, Jia H, Cornes BK, Chen LJ, Qiao C, et al.
    PLoS Genet, 2014 Mar;10(3):e1004089.
    PMID: 24603532 DOI: 10.1371/journal.pgen.1004089
    Anterior chamber depth (ACD) is a key anatomical risk factor for primary angle closure glaucoma (PACG). We conducted a genome-wide association study (GWAS) on ACD to discover novel genes for PACG on a total of 5,308 population-based individuals of Asian descent. Genome-wide significant association was observed at a sequence variant within ABCC5 (rs1401999; per-allele effect size =  -0.045 mm, P = 8.17 × 10(-9)). This locus was associated with an increase in risk of PACG in a separate case-control study of 4,276 PACG cases and 18,801 controls (per-allele OR = 1.13 [95% CI: 1.06-1.22], P = 0.00046). The association was strengthened when a sub-group of controls with open angles were included in the analysis (per-allele OR = 1.30, P = 7.45 × 10(-9); 3,458 cases vs. 3,831 controls). Our findings suggest that the increase in PACG risk could in part be mediated by genetic sequence variants influencing anterior chamber dimensions.
    Matched MeSH terms: Multidrug Resistance-Associated Proteins/genetics*
  2. ABCC2 rs2273697 and rs3740066 polymorphisms and resistance to antiepileptic drugs in Asia Pacific epilepsy cohorts
    Sha'ari HM, Haerian BS, Baum L, Saruwatari J, Tan HJ, Rafia MH, et al.
    Pharmacogenomics, 2014 Mar;15(4):459-66.
    PMID: 24624913 DOI: 10.2217/pgs.13.239
    To examine the relevance of ABCC2 polymorphisms to drug responsiveness in epilepsy cohorts from the Asia Pacific region.
    Matched MeSH terms: Multidrug Resistance-Associated Proteins/genetics*
  3. Fulltext Linkage disequilibrium between polymorphisms of ABCB1 and ABCC2 to predict the treatment outcome of Malaysians with complex partial seizures on treatment with carbamazepine mono-therapy at the Kuala Lumpur Hospital
    Subenthiran S, Abdullah NR, Joseph JP, Muniandy PK, Mok BT, Kee CC, et al.
    PLoS One, 2013;8(5):e64827.
    PMID: 23717663 DOI: 10.1371/journal.pone.0064827
    Carbamazepine (CBZ) is used as the first line of treatment of Complex Partial Seizures (CPS) in the Epilepsy Clinic, Neurology Department of Kuala Lumpur Hospital (KLH). More than 30% of the patients remain drug resistant to CBZ mono-therapy. CBZ is transported by the P-glycoprotein (P-gp). The P-gp encoded by the ABCB1 and ABCC2 genes are expressed in drug resistant patients with epilepsy. A few studies have shown significant association between CBZ resistant epilepsy and Linkage Disequilibrium (LD) with adjacent polymorphisms of these genes. Our study is aimed at determining the correlation between patients' response to CBZ mono-therapy to Single Nucleotide Polymorphisms G2677T and C3435T of the ABCB1 gene as well as G1249A and -24C>T of the ABCC2 gene.
    Matched MeSH terms: Multidrug Resistance-Associated Proteins/genetics*
  4. Genetic variations of the ABCC2 gene in the Chinese, Malay, and Indian populations of Singapore
    Ho WF, Koo SH, Yee JY, Lee JD
    Drug Metab. Pharmacokinet., 2008;23(5):385-91.
    PMID: 18974617
    MRP2 is a drug transporter that is responsible for the gastrointestinal absorption and biliary excretion of a wide variety of endogenous and xenobiotic compounds, including many clinically used drugs. This study aims to identify genetic variations of ABCC2 gene in three distinct ethnic groups of the Singaporean population (n = 288). The coding region of the gene encoding the transporter protein was screened for genetic variations in the study population by denaturing high-performance liquid chromatography and DNA sequencing. Twenty-two genetic variations of ABCC2, including 8 novel ones, were found: 1 in the 5' untranslated region, 10 in the coding exons (8 nonsynonymous and 2 synonymous variations), and 11 in the introns. Three novel nonsynonymous variations: 2686G > A (Glu896Lys), 4240C > T (His1414Tyr) and 4568A > C (Gln1523Pro) were detected in single heterozygous Malay, Chinese, and Indian subjects, respectively. Among the novel nonsynonymous variations, 4240C > T and 4568A > C were predicted to be functionally significant. These data would provide fundamental and useful information for pharmacogenetic studies on drugs that are substrates of MRP2 in Asians.
    Matched MeSH terms: Multidrug Resistance-Associated Proteins/genetics*
  5. Fulltext Partial characterization of genes encoding the ATP-binding cassette proteins of Cryptosporidium parvum
    Li LC, Mun YF
    Trop Biomed, 2005 Dec;22(2):115-22.
    PMID: 16883276
    The present study aims to explore the possible mechanisms underlying the multidrug resistance characteristic of Cryptosporidium parvum by detecting the presence of ATP-binding cassette (ABC) protein encoding genes, especially one that shows high similarity to members belonging to the multidrug resistance protein (MDR) and multidrug resistance associated protein (MRP) subfamilies. PCR using ABC-specific degenerate primers successfully amplified two unique fragments, designated Cpnbd1 and Cpnbd2, from C. parvum genomic DNA. Cpnbd1 exhibited high degree of homology (99-100%) with the nucleotide- binding domains (NBDs) at the NH2 -terminal halves of two previously reported ABC proteins (CpABC and CpABC1) of human and bovine origin C. parvum isolates. It is likely that CpABC, CpABC1 and Cpnbd1 were encoded by homologous genes of a type of ABC transporter protein found in different C. parvum isolates. However, Cpnbd2 showed moderate levels of similarities (28-49%) to the NBDs of four ABC proteins characterised in C. parvum to date. Therefore, Cpnbd2 could be a novel member of an ABC superfamily of proteins in C. parvum. Phylogenetic analyses on a list of ABC transporters known to associate with MDR phenotype has significantly linked Cpnbd1 and Cpnbd2 to these transporters, thus suggesting that Cpnbd1 and Cpnbd2 proteins may contribute to the intrinsic multidrug resistance phenotype of C. parvum.
    Matched MeSH terms: Multidrug Resistance-Associated Proteins/genetics*
  6. Association of Allelic Interaction of Single Nucleotide Polymorphisms of Influx and Efflux Transporters Genes With Nonhematologic Adverse Events of Docetaxel in Breast Cancer Patients
    Jabir RS, Ho GF, Annuar MABA, Stanslas J
    Clin Breast Cancer, 2018 10;18(5):e1173-e1179.
    PMID: 29885788 DOI: 10.1016/j.clbc.2018.04.018
    PURPOSE: Nonhematologic adverse events (AEs) of docetaxel constitute an extra burden in the treatment of cancer patients and necessitate either a dose reduction or an outright switch of docetaxel for other regimens. These AEs are frequently associated with genetic polymorphisms of genes encoding for proteins involved docetaxel disposition. Therefore, we investigated that association in Malaysian breast cancer patients.

    MATERIALS AND METHODS: A total of 110 Malaysian breast cancer patients were enrolled in the present study, and their blood samples were investigated for different single nucleotide polymorphisms using polymerase chain reaction restriction fragment length polymorphism. AEs were evaluated using the Common Terminology Criteria for Adverse Events, version 4.0.

    RESULTS: Fatigue, nausea, oral mucositis, and vomiting were the most common nonhematologic AEs. Rash was associated with heterozygous and mutant genotypes of ABCB1 3435C>T (P < .05). Moreover, patients carrying the GG genotype of ABCB1 2677G>A/T reported more fatigue than those carrying the heterozygous genotype GA (P < .05). The presence of ABCB1 3435-T, ABCC2 3972-C, ABCC2 1249-G, and ABCB1 2677-G alleles was significantly associated with nausea and oral mucositis. The coexistence of ABCB1 3435-C, ABCC2 3972-C, ABCC2 1249-G, and ABCB1 2677-A was significantly associated with vomiting (P < .05).

    CONCLUSION: The prevalence of nonhematologic AEs in breast cancer patients treated with docetaxel has been relatively high. The variant allele of ABCB1 3435C>T polymorphism could be a potential predictive biomarker of docetaxel-induced rash, and homozygous wild-type ABCB1 2677G>A/T might predict for a greater risk of fatigue. In addition, the concurrent presence of specific alleles could be predictive of vomiting, nausea, and oral mucositis.

    Matched MeSH terms: Multidrug Resistance-Associated Proteins/genetics
  7. Fulltext The detection of pfcrt and pfmdr1 point mutations as molecular markers of chloroquine drug resistance, Pahang, Malaysia
    Atroosh WM, Al-Mekhlafi HM, Mahdy MA, Surin J
    Malar J, 2012;11:251.
    PMID: 22853645 DOI: 10.1186/1475-2875-11-251
    Malaria is still a public health problem in Malaysia with chloroquine (CQ) being the first-line drug in the treatment policy of uncomplicated malaria. There is a scarcity in information about the magnitude of Plasmodium falciparum CQ resistance. This study aims to investigate the presence of single point mutations in the P. falciparum chloroquine-resistance transporter gene (pfcrt) at codons 76, 271, 326, 356 and 371 and in P. falciparum multi-drug resistance-1 gene (pfmdr1) at codons 86 and 1246, as molecular markers of CQ resistance.
    Matched MeSH terms: Multidrug Resistance-Associated Proteins/genetics*
  8. Survey of chloroquine-resistant mutations in the Plasmodium falciparum pfcrt and pfmdr-1 genes in Hadhramout, Yemen
    Bamaga OA, Mahdy MA, Lim YA
    Acta Trop, 2015 Sep;149:59-63.
    PMID: 26001972 DOI: 10.1016/j.actatropica.2015.05.013
    Malaria is still a major public health problem in Yemen. More than 95% of the malaria cases are due to Plasmodium ‎falciparum‎. Recently in Yemen, the antimalarial treatment policy was changed from chloroquine (CQ) to artemisinin combination therapy (ACTs). However, CQ is still available and prescribed in the Yemeni market. The persistence of CQ resistance will be prolonged if the shift to ACT and the simultaneous withdrawal of CQ are not rigorously implemented. The aim of the current survey is to detect chloroquine-resistant mutations in P. falciparum chloroquine-resistance transporter (pfcrt) and P. falciparum multi-drug resistance-1 (pfmdr1) genes. These data will be important for future monitoring and assessment of antimalarial drug policy in Yemen. Blood specimens were collected from 735 individuals from different districts of the Hadhramout province, Yemen by house-to-house visit. Mutation-specific nested polymerase chain reaction (PCR) and restriction fragment length polymorphism (PCR-RFLP) methods were used to investigate the mutations in the pfmdr1(codons 86 and 1246) and pfcrt (codons 76, 271, 326, 356 and 371) genes. The overall prevalence of pfcrt mutations at codons 76, 271, 326 and 371 were 50.4%, 58.7%, 54.3% and 44.9%, respectively. All isolates had wild-type pfcrt 356 allele. The majority of pfmdr1 86 alleles (83.3%) and all pfmdr1 1246 alleles were wild type. There was no association between pfcrt mutations and symptomatology, gender and age groups. In conclusion, point mutations in codons 76, 271, 326 and 371 of pfcrt of P. falciparum are high suggesting a sustained high CQ resistance even after 4 years of shifting to ACTs. These findings warrant complete withdrawal of CQ use from the Yemeni market for P. falciparum and careful usage of CQ for treating Plasmodium vivax.
    Matched MeSH terms: Multidrug Resistance-Associated Proteins/genetics*
  9. Efflux genes and active efflux activity detection in Malaysian clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA)
    Saiful AJ, Mastura M, Zarizal S, Mazurah MI, Shuhaimi M, Ali AM
    J Basic Microbiol, 2008 Aug;48(4):245-51.
    PMID: 18720500 DOI: 10.1002/jobm.200700387
    Efflux-mediated resistance has been recognized as an important contributor of antibiotic resistance in bacteria, especially in methicillin-resistant Staphylococcus aureus (MRSA) isolates. This study was carried out to detect and analyze efflux genes (norA and mdeA) and active efflux activity in a collection of Malaysian MRSA and methicillin-sensitive S. aureus (MSSA) clinical isolates. Nineteen isolates including three ATCC S. aureus reference strains were subjected to PCR detection and DNA sequence analysis for norA and mdeA and active efflux detection using modified minimum inhibitory concentration (MIC) assay. From the 19 isolates, 18 isolates harboured the mdeA gene while 16 isolates contained norA gene. DNA sequence analysis reveals 98-100% correlation between the PCR product and the published DNA sequences in GenBank. In addition, 16 isolates exhibited active efflux activity using the ethidium bromide (EtBr)-reserpine combination MIC assay. To our knowledge, this is the first report on the detection of efflux genes and active efflux activity amongst Malaysian clinical isolates of MRSA/MSSA. Detection of active efflux activity may explain the previous report on efflux-mediated drug resistance profile amongst the local clinical isolates.
    Matched MeSH terms: Multidrug Resistance-Associated Proteins/genetics*
  10. Fulltext High prevalence of pfcrt K76t mutants among Plasmodium falciparum isolates from Sabah, Malaysia
    Norahmad NA, Abdullah NR, Yaccob N, Jelip J, Dony JF, Ruslan KF, et al.
    Southeast Asian J Trop Med Public Health, 2011 Nov;42(6):1322-6.
    PMID: 22299399
    Chloroquine (CQ) remains the first line drug for the prevention and treatment of malaria in Malaysia in spite of the fact that resistance to CQ has been observed in Malaysia since the 1960s. CQ-resistance is associated with various mutations in pfcrt, which encodes a putative transporter located in the digestive vacuolar membrane of P. falciparum. Substitution of lysine (K) to threonine (T) at amino acid 76 (K76T) in pfcrt is the primary genetic marker conferring resistance to CQ. To determine the presence of T76 mutation in pfcrt from selected areas of Kalabakan, Malaysia 619 blood samples were screened for P. falciparum, out of which 31 were positive. Blood samples were collected on 3 MM Whatman filter papers and DNA was extracted using QIAmp DNA mini kit. RFLP-PCR for the detection of the CQ-resistant T76 and sensitive K76 genotype was carried out. Twenty-five samples were shown to have the point mutation in pfcrt whereas the remaining samples were classified as CQ-sensitive (wild-type). In view of the fact that CQ is the first line anti-malarial drug in Malaysia, this finding could be an important indication that treatment with CQ may no longer be effective in the future.
    Matched MeSH terms: Multidrug Resistance-Associated Proteins/genetics
  11. Fulltext Influence of the pfmdr1 Gene on In Vitro Sensitivities of Piperaquine in Thai Isolates of Plasmodium falciparum
    Mungthin M, Watanatanasup E, Sitthichot N, Suwandittakul N, Khositnithikul R, Ward SA
    Am J Trop Med Hyg, 2017 03;96(3):624-629.
    PMID: 28044042 DOI: 10.4269/ajtmh.16-0668
    Piperaquine combined with dihydroartemisinin is one of the artemisinin derivative combination therapies, which can replace artesunate-mefloquine in treating uncomplicated falciparum malaria in Thailand. The aim of this study was to determine the in vitro sensitivity of Thai Plasmodium falciparum isolates against piperaquine and the influence of the pfmdr1 gene on in vitro response. One hundred and thirty-seven standard laboratory and adapted Thai isolates of P. falciparum were assessed for in vitro piperaquine sensitivity. Polymorphisms of the pfmdr1 gene were determined by polymerase chain reaction methods. The mean and standard deviation of the piperaquine IC50 in Thai isolates of P. falciparum were 16.7 ± 6.3 nM. The parasites exhibiting chloroquine IC50 of ≥ 100 nM were significantly less sensitive to piperaquine compared with the parasite with chloroquine IC50 of < 100 nM. No significant association between the pfmdr1 copy number and piperaquine IC50 values was found. In contrast, the parasites containing the pfmdr1 86Y allele exhibited significantly reduced piperaquine sensitivity. Before nationwide implementation of dihydroartemisinin-piperaquine as the first-line treatment in Thailand, in vitro and in vivo evaluations of this combination should be performed especially in areas where parasites containing the pfmdr1 86Y allele are predominant such as the Thai-Malaysian border.
    Matched MeSH terms: Multidrug Resistance-Associated Proteins/genetics*
  12. Clinical impact of ABCC1 and ABCC2 genotypes and haplotypes in mediating imatinib resistance among chronic myeloid leukaemia patients
    Au A, Baba AA, Azlan H, Norsa'adah B, Ankathil R
    J Clin Pharm Ther, 2014 Dec;39(6):685-90.
    PMID: 25060527 DOI: 10.1111/jcpt.12197
    The introduction and success of imatinib mesylate (IM) has brought about a paradigm shift in chronic myeloid leukaemia (CML) treatment. However, despite the high efficacy of IM, clinical resistance develops due to a heterogeneous array of mechanisms. Pharmacogenetic variability as a result of genetic polymorphisms could be one of the most important factors influencing resistance to IM. The aim of this study was to investigate the association between genetic variations in drug efflux transporter ABCC1 (MRP1) and ABCC2 (MRP2) genes and response to IM in patients with CML.
    Matched MeSH terms: Multidrug Resistance-Associated Proteins/genetics*
  13. Multidrug resistance protein 2 genetic polymorphism and colorectal cancer recurrence in patients receiving adjuvant FOLFOX-4 chemotherapy
    Mirakhorli M, Rahman SA, Abdullah S, Vakili M, Rozafzon R, Khoshzaban A
    Mol Med Rep, 2013 Feb;7(2):613-7.
    PMID: 23232902 DOI: 10.3892/mmr.2012.1226
    Multidrug resistance protein 2 (MRP2), encoded by the ATP-binding cassette C2 (ABCC2) gene, is an efflux pump located on the apical membrane of many polarized cells, which transports conjugate compounds by an ATP-dependent mechanism. The correlation of G1249A ABCC2 polymorphism with the development of colorectal cancer (CRC) and poor prognosis was evaluated in patients who were treated with fluorouracil/-leucovorin (FL) plus oxaliplatin (FOLFOX-4). A total of 50 paraffin‑embedded tissue samples collected from CRC patients were analyzed to identify the polymorphism. Patients were in stage II/III and received postoperative FOLFOX-4 chemotherapy. As a control group, an equal number of unrelated healthy subjects were enrolled in the study. The polymorphism was genotyped by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, and results were compared with clinicopathological markers, early relapse and survival rates. During the 12 months of follow-up, local and distant recurrences were observed in 15 (30%) patients. No significant difference in the distribution of wild-type and polymorphic genotypes was observed between the patient and control groups and between the patients who experienced recurrence within 1 year and those who did not (all P>0.05). In conclusion, the G1249A polymorphism is not associated with CRC risk and early recurrence. However, significant correlation was observed between G1249A polymorphism and the overall survival and disease-free survival of the patients.
    Matched MeSH terms: Multidrug Resistance-Associated Proteins/genetics*
  14. siRNAs targeting multidrug transporter genes sensitise breast tumour to doxorubicin in a syngeneic mouse model
    Tiash S, Chowdhury EH
    J Drug Target, 2019 03;27(3):325-337.
    PMID: 30221549 DOI: 10.1080/1061186X.2018.1525388
    Chemotherapy, the commonly favoured approach to treat cancer is frequently associated with treatment failure and recurrence of disease as a result of development of multidrug resistance (MDR) with concomitant over-expression of drug efflux proteins on cancer cells. One of the most widely used drugs, doxorubicin (Dox) is a substrate of three different ATP-binding cassette (ABC) transporters, namely, ABCB1, ABCG2 and ABCC1, predominantly contributing to MDR phenotype in cancer. To silence these transporter-coding genes and thus enhance the therapeutic efficacy of Dox, pH-sensitive carbonate apatite (CA) nanoparticles (NPs) were employed as a carrier system to co-deliver siRNAs against these genes and Dox in breast cancer cells and in a syngeneic breast cancer mouse model. siRNAs and Dox were complexed with NPs by incubation at 37 °C and used to treat cancer cell lines to check cell viability and caspase-mediated signal. 4T1 cells-induced breast cancer mouse model was used for treatment with the complex to confirm their action in tumour regression. Smaller (∼200 nm) and less polydisperse NPs that were taken up more effectively by tumour tissue could enhance Dox chemosensitivity, significantly reducing the tumour size in a very low dose of Dox (0.34 mg/kg), in contrast to the limited effect observed in breast cancer cell lines. The study thus proposes that simultaneous delivery of siRNAs against transporter genes and Dox with the help of CA NPs could be a potential therapeutic intervention in effectively treating MDR breast cancer.
    Matched MeSH terms: Multidrug Resistance-Associated Proteins/genetics
  15. Fulltext Characterization of malaria infection at two border areas of Thailand adjoining with Myanmar and Malaysia
    Sermwittayawong N, Nishibuchi M, Sawangjaroen N, Vuddhakul V
    Southeast Asian J Trop Med Public Health, 2015 Jul;46(4):551-7.
    PMID: 26867373
    During 2009 to 2010, a total of 408 blood samples collected from malaria patients in Ranong (149) and Yala (259) Provinces, Thailand were investigated for Plasmodium spp using microscopic examination. There are no statistical differences in the prevalence of P. falciparum and P. vivax in samples collected from Ranong and Yala (46% vs 52%, and 54% vs 45%, respectively). Single nucleotide polymorphism of codon 86 in pfmdr1 (encoding P. falciparum multidrug resistance protein 1) was investigated among 75 samples of P. falciparum and 2 samples of P. knowlesi. A pfmdr1 N86Y mutation was detected in 1 out of 29 samples and 45 out of 46 samples obtained from Ranong and Yala Provinces, respectively. It is interesting that pfmdr1 was detected in two P. knowlesi DNA samples obtained previously from Ranong Province which was 99% homologous to pfmdr1 obtained from falciparum parasites in the same area but the mutation was not observed. The difference in multidrug resistance protein in Plasmodium obtained from those two border areas of Thailand will be of use in monitoring drug resistance in these border regions of the country.
    Matched MeSH terms: Multidrug Resistance-Associated Proteins/genetics
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