Displaying publications 1 - 20 of 25 in total

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  1. Secukinumab in the treatment of a child with congenital ichthyosiform erythroderma with ABCA12 mutation
    Albela H, Leong KF
    Int J Dermatol, 2023 Jan;62(1):e27-e29.
    PMID: 35933655 DOI: 10.1111/ijd.16378
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics
  2. The Impacts and Changes Related to the Cancer Drug Resistance Mechanism
    Varshney P, Sharma V, Yadav D, Kumar Y, Singh A, Kagithala NR, et al.
    Curr Drug Metab, 2023;24(12):787-802.
    PMID: 38141188 DOI: 10.2174/0113892002266408231207150547
    BACKGROUND: Cancer drug resistance remains a difficult barrier to effective treatment, necessitating a thorough understanding of its multi-layered mechanism.

    OBJECTIVE: This study aims to comprehensively explore the diverse mechanisms of cancer drug resistance, assess the evolution of resistance detection methods, and identify strategies for overcoming this challenge. The evolution of resistance detection methods and identification strategies for overcoming the challenge.

    METHODS: A comprehensive literature review was conducted to analyze intrinsic and acquired drug resistance mechanisms, including altered drug efflux, reduced uptake, inactivation, target mutations, signaling pathway changes, apoptotic defects, and cellular plasticity. The evolution of mutation detection techniques, encompassing clinical predictions, experimental approaches, and computational methods, was investigated. Strategies to enhance drug efficacy, modify pharmacokinetics, optimizoptimizee binding modes, and explore alternate protein folding states were examined.

    RESULTS: The study comprehensively overviews the intricate mechanisms contributing to cancer drug resistance. It outlines the progression of mutation detection methods and underscores the importance of interdisciplinary approaches. Strategies to overcome drug resistance challenges, such as modulating ATP-binding cassette transporters and developing multidrug resistance inhibitors, are discussed. The study underscores the critical need for continued research to enhance cancer treatment efficacy.

    CONCLUSION: This study provides valuable insights into the complexity of cancer drug resistance mechanisms, highlights evolving detection methods, and offers potential strategies to enhance treatment outcomes.

    Matched MeSH terms: ATP-Binding Cassette Transporters/metabolism
  3. An effective extracellular protein secretion by an ABC transporter system in Escherichia coli: statistical modeling and optimization of cyclodextrin glucanotransferase secretory production
    Low KO, Mahadi NM, Rahim RA, Rabu A, Abu Bakar FD, Murad AM, et al.
    J Ind Microbiol Biotechnol, 2011 Sep;38(9):1587-97.
    PMID: 21336875 DOI: 10.1007/s10295-011-0949-0
    Direct transport of recombinant protein from cytosol to extracellular medium offers great advantages, such as high specific activity and a simple purification step. This work presents an investigation on the potential of an ABC (ATP-binding cassette) transporter system, the hemolysin transport system, for efficient protein secretion in Escherichia coli (E. coli). A higher secretory production of recombinant cyclodextrin glucanotransferase (CGTase) was achieved by a new plasmid design and subsequently by optimization of culture conditions via central composite design. An improvement of at least fourfold extracellular recombinant CGTase was obtained using the new plasmid design. The optimization process consisted of 20 experiments involving six star points and six replicates at the central point. The predicted optimum culture conditions for maximum recombinant CGTase secretion were found to be 25.76 μM IPTG, 1.0% (w/v) arabinose and 34.7°C post-induction temperature, with a predicted extracellular CGTase activity of 68.76 U/ml. Validation of the model gave an extracellular CGTase activity of 69.15 ± 0.71 U/ml, resulting in a 3.45-fold increase compared to the initial conditions. This corresponded to an extracellular CGTase yield of about 0.58 mg/l. We showed that a synergistic balance of transported protein and secretory pathway is important for efficient protein transport. In addition, we also demonstrated the first successful removal of the C-terminal secretion signal from the transported fusion protein by thrombin proteolytic cleavage.
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics; ATP-Binding Cassette Transporters/metabolism*
  4. Cloning and functional expression of novel cholesterol transporters ABCG1 and ABCG4 in gonadotropin-releasing hormone neurons of the tilapia
    Phang YL, Soga T, Kitahashi T, Parhar IS
    Neuroscience, 2012 Feb 17;203:39-49.
    PMID: 22198513 DOI: 10.1016/j.neuroscience.2011.12.016
    In addition to reproduction, gonadotropin-releasing hormone (GnRH) has been postulated to control cholesterol metabolism via cholesterol transport, which is carried out partly by the members of ATP-binding cassette (ABC) transporters G1 (ABCG1) and G4 (ABCG4). However, there is yet to be evidence demonstrating the relationship between these transporters with reference to GnRH neurons. In the present study, we cloned two ABCG1 messenger RNA (mRNA) variants and one ABCG4 mRNA and examined their expression in the brain including GnRH neurons (GnRH1, GnRH2, and GnRH3) in the cichlid tilapia (Oreochromis niloticus). Comparison of nucleotide sequences of the tilapia ABCG1 and ABCG4 with that of other fish species showed that both of these genes are evolutionarily conserved among fishes. ABCG1 and ABCG4 were shown to have high mRNA expressions in the CNS, pituitary, and gonads. In the brain, real-time polymerase chain reaction (PCR) showed that ABCG4 mRNA was higher than ABCG1a in all brain regions including the olfactory bulb (ABCG1=13.34, ABCG4=6796.35; P<0.001), dorsal telencephalon (ABCG1=8.64, ABCG4=10149.13; P=0.001), optic tectum (ABCG1=22.12, ABCG4=13931.04; P<0.01), cerebellum (ABCG1=8.68, ABCG4=12382.90; P<0.01), and preoptic area-midbrain-hypothalamus (ABCG1=21.36, ABCG4=13255.41; P=0.001). Similarly, although ABCG1 mRNA level is much higher in the pituitary compared with the brain, it was still significantly lower compared with ABCG4 (ABCG1=337.73, ABCG4=1157.87; P=0.01). The differential pattern of expression of ABCG1 and ABCG4 in the brain versus pituitary suggests that the two transporters are regulated by different mechanisms. Furthermore, ABCG1 and ABCG4 mRNA expressions were found in all three types of laser-captured GnRH neurons with highly similar percentage of expressions, suggesting that cholesterol efflux from GnRH neurons may require heterodimerization of both ABCG1 and ABCG4.
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics*; ATP-Binding Cassette Transporters/metabolism
  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: ATP-Binding Cassette Transporters/genetics*; ATP-Binding Cassette Transporters/chemistry
  6. Resistance Mechanism in a Terbinafine-Resistant Strain of Microsporum canis
    Kano R, Hsiao YH, Siew HH, Chen C, Hasegawa A, Kamata H
    Mycopathologia, 2018 Jan 16.
    PMID: 29340910 DOI: 10.1007/s11046-018-0242-0
    To clarify the terbinafine (TRF) resistance mechanism in a TRF-resistant strain of Microsporum canis, the expression of the pleiotropic drug resistance (PDR1), multidrug resistance (MDR1), MDR2 and MDR4 genes were investigated by real-time quantitative PCR (RT-qPCR) analysis, given the known interaction of the corresponding proteins with antifungals and with the efflux blocker FK506. The expression of the PDR1, MDR1, MDR2 and MDR4 genes was 2-4 times higher in the TRF-resistant strain grown in the presence of 0.14 µg/mL of TRF than in TRF-susceptible strains cultured in the absence of TRF. The TRF-resistant strain exhibited MICs of > 32 µg/mL for TRF alone; this resistance was attenuated to an MIC of 8 µg/mL in the presence of FK506, indicating that the TRF inhibitory concentration index value was
    Matched MeSH terms: ATP-Binding Cassette Transporters
  7. Fulltext A novel rare copy number variant of the ABCF1 gene identified among dengue fever patients from Peninsular Malaysia
    Hoh BP, Sam SS, Umi SH, Mahiran M, Nik Khairudin NY, Rafidah Hanim S, et al.
    Genet. Mol. Res., 2014;13(1):980-5.
    PMID: 24634119 DOI: 10.4238/2014.February.19.9
    Copy number variation (CNV) is a form of genetic variation in addition to single nucleotide polymorphisms. The significance of CNV in the manifestation of a number of diseases is only recently receiving considerable attention. We genotyped 163 dengue patients from Peninsular Malaysia for genes possibly linked to dengue infection using quantitative real-time PCR. Here, we report a serendipitous discovery of a novel rare CNV of the ABCF1 gene among the dengue patients. Among these patients, two had a gain of 1 copy (CN = 3) and one had lost 1 copy (CN = 1), indicating that a rare CNV of the ABCF1 gene was detected among dengue patients from Peninsular Malaysia. Although the gene is suspected to regulate inflammatory responses and pathogen-induced cytokine storm, its relevance to dengue requires further investigation.
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics*
  8. Mutational analyses on X-linked adrenoleukodystrophy reveal a novel cryptic splicing and three missense mutations in the ABCD1 gene
    Hung KL, Wang JS, Keng WT, Chen HJ, Liang JS, Ngu LH, et al.
    Pediatr Neurol, 2013 Sep;49(3):185-90.
    PMID: 23835273 DOI: 10.1016/j.pediatrneurol.2013.04.021
    X-linked adrenoleukodystrophy is caused by a defective peroxisomal membrane transporter, ABCD1, responsible for transporting very-long-chain fatty acid substrate into peroxisomes for degradation. The main biochemical defect, which is also one of the major diagnostic hallmarks, of X-linked adrenoleukodystrophy is the accumulation of saturated very-long-chain fatty acids in all tissues and body fluids.
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics*
  9. Fulltext Distribution of pfmdr1 polymorphisms in Plasmodium falciparum isolated from Southern Thailand
    Mungthin M, Intanakom S, Suwandittakul N, Suida P, Amsakul S, Sitthichot N, et al.
    Malar J, 2014;13:117.
    PMID: 24670242 DOI: 10.1186/1475-2875-13-117
    Drug resistance in Plasmodium falciparum is a major problem in malaria control especially along the Thai-Myanmar and Thai-Cambodia borders. To date, a few molecular markers have been identified for anti-malarial resistance in P. falciparum, including the P. falciparum chloroquine resistance transporter (pfcrt) and the P. falciparum multidrug resistance 1 (pfmdr1). However no information is available regarding the distribution pattern of these gene polymorphisms in the parasites from the Thai-Malaysia border. This study was conducted to compare the distribution pattern of the pfcrt and pfmdr1 polymorphisms in the parasites from the lower southern provinces, Thai-Malaysia border and the upper southern provinces, Thai-Myanmar border. In addition, in vitro sensitivities of anti-malarial drugs including chloroquine, mefloquine, quinine, and artesunate were determined.
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics*; ATP-Binding Cassette Transporters/metabolism
  10. Fulltext Burkholderia pseudomallei kills Caenorhabditis elegans through virulence mechanisms distinct from intestinal lumen colonization
    Ooi SK, Lim TY, Lee SH, Nathan S
    Virulence, 2012 Oct 01;3(6):485-96.
    PMID: 23076282 DOI: 10.4161/viru.21808
    The nematode Caenorhabditis elegans is hypersusceptible to Burkholderia pseudomallei infection. However, the virulence mechanisms underlying rapid lethality of C. elegans upon B. pseudomallei infection remain poorly defined. To probe the host-pathogen interaction, we constructed GFP-tagged B. pseudomallei and followed bacterial accumulation within the C. elegans intestinal lumen. Contrary to slow-killing by most bacterial pathogens, B. pseudomallei caused fairly limited intestinal lumen colonization throughout the period of observation. Using grinder-defective mutant worms that allow the entry of intact bacteria also did not result in full intestinal lumen colonization. In addition, we observed a significant decline in C. elegans defecation and pharyngeal pumping rates upon B. pseudomallei infection. The decline in defecation rates ruled out the contribution of defecation to the limited B. pseudomallei colonization. We also demonstrated that the limited intestinal lumen colonization was not attributed to slowed host feeding as bacterial loads did not change significantly when feeding was stimulated by exogenous serotonin. Both these observations confirm that B. pseudomallei is a poor colonizer of the C. elegans intestine. To explore the possibility of toxin-mediated killing, we examined the transcription of the C. elegans ABC transporter gene, pgp-5, upon B. pseudomallei infection of the ppgp-5::gfp reporter strain. Expression of pgp-5 was highly induced, notably in the pharynx and intestine, compared with Escherichia coli-fed worms, suggesting that the host actively thwarted the pathogenic assaults during infection. Collectively, our findings propose that B. pseudomallei specifically and continuously secretes toxins to overcome C. elegans immune responses.
    Matched MeSH terms: ATP-Binding Cassette Transporters/biosynthesis; ATP-Binding Cassette Transporters/genetics*; ATP-Binding Cassette Transporters/metabolism
  11. Mutation study for 9 genes in 23 unrelated patients with autosomal recessive congenital ichthyosis in Japan and Malaysia
    Numata S, Teye K, Krol RP, Karashima T, Fukuda S, Matsuda M, et al.
    J. Dermatol. Sci., 2015 Apr;78(1):82-5.
    PMID: 25766764 DOI: 10.1016/j.jdermsci.2015.02.006
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics*
  12. Enhanced secretory production of hemolysin-mediated cyclodextrin glucanotransferase in Escherichia coli by random mutagenesis of the ABC transporter system
    Low KO, Mahadi NM, Abdul Rahim R, Rabu A, Abu Bakar FD, Abdul Murad AM, et al.
    J Biotechnol, 2010 Dec;150(4):453-9.
    PMID: 20959127 DOI: 10.1016/j.jbiotec.2010.10.001
    The hemolysin transport system was found to mediate the release of cyclodextrin glucanotransferase (CGTase) into the extracellular medium when it was fused to the C-terminal 61 amino acids of HlyA (HlyAs(61)). To produce an improved-secretion variant, the hly components (hlyAs, hlyB and hlyD) were engineered by directed evolution using error-prone PCR. Hly mutants were screened on solid LB-starch plate for halo zone larger than the parent strain. Through screening of about 1 × 10(4) Escherichia coli BL21(DE3) transformants, we succeeded in isolating five mutants that showed a 35-217% increase in the secretion level of CGTase-HlyAs(61) relative to the wild-type strain. The mutation sites of each mutant were located at HlyB, primarily along the transmembrane domain, implying that the corresponding region was important for the improved secretion of the target protein. In this study we describe the finding of novel site(s) of HlyB responsible for enhancing secretion of CGTase in E. coli.
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics*
  13. Fulltext Positive selection in Europeans and East-Asians at the ABCA12 gene
    Sirica R, Buonaiuto M, Petrella V, Sticco L, Tramontano D, Antonini D, et al.
    Sci Rep, 2019 03 19;9(1):4843.
    PMID: 30890716 DOI: 10.1038/s41598-019-40360-9
    Natural selection acts on genetic variants by increasing the frequency of alleles responsible for a cellular function that is favorable in a certain environment. In a previous genome-wide scan for positive selection in contemporary humans, we identified a signal of positive selection in European and Asians at the genetic variant rs10180970. The variant is located in the second intron of the ABCA12 gene, which is implicated in the lipid barrier formation and down-regulated by UVB radiation. We studied the signal of selection in the genomic region surrounding rs10180970 in a larger dataset that includes DNA sequences from ancient samples. We also investigated the functional consequences of gene expression of the alleles of rs10180970 and another genetic variant in its proximity in healthy volunteers exposed to similar UV radiation. We confirmed the selection signal and refine its location that extends over 35 kb and includes the first intron, the first two exons and the transcription starting site of ABCA12. We found no obvious effect of rs10180970 alleles on ABCA12 gene expression. We reconstructed the trajectory of the T allele over the last 80,000 years to discover that it was specific to H. sapiens and present in non-Africans 45,000 years ago.
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics*
  14. A comparative genomic analysis of the alkalitolerant soil bacterium Bacillus lehensis G1
    Noor YM, Samsulrizal NH, Jema'on NA, Low KO, Ramli AN, Alias NI, et al.
    Gene, 2014 Jul 25;545(2):253-61.
    PMID: 24811681 DOI: 10.1016/j.gene.2014.05.012
    Bacillus lehensis G1 is a Gram-positive, moderately alkalitolerant bacterium isolated from soil samples. B. lehensis produces cyclodextrin glucanotransferase (CGTase), an enzyme that has enabled the extensive use of cyclodextrin in foodstuffs, chemicals, and pharmaceuticals. The genome sequence of B. lehensis G1 consists of a single circular 3.99 Mb chromosome containing 4017 protein-coding sequences (CDSs), of which 2818 (70.15%) have assigned biological roles, 936 (23.30%) have conserved domains with unknown functions, and 263 (6.55%) have no match with any protein database. Bacillus clausii KSM-K16 was established as the closest relative to B. lehensis G1 based on gene content similarity and 16S rRNA phylogenetic analysis. A total of 2820 proteins from B. lehensis G1 were found to have orthologues in B. clausii, including sodium-proton antiporters, transport proteins, and proteins involved in ATP synthesis. A comparative analysis of these proteins and those in B. clausii and other alkaliphilic Bacillus species was carried out to investigate their contributions towards the alkalitolerance of the microorganism. The similarities and differences in alkalitolerance-related genes among alkalitolerant/alkaliphilic Bacillus species highlight the complex mechanism of pH homeostasis. The B. lehensis G1 genome was also mined for proteins and enzymes with potential viability for industrial and commercial purposes.
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics; ATP-Binding Cassette Transporters/metabolism
  15. Fulltext Tualang honey improves human corneal epithelial progenitor cell migration and cellular resistance to oxidative stress in vitro
    Tan JJ, Azmi SM, Yong YK, Cheah HL, Lim V, Sandai D, et al.
    PLoS One, 2014;9(5):e96800.
    PMID: 24802273 DOI: 10.1371/journal.pone.0096800
    Stem cells with enhanced resistance to oxidative stress after in vitro expansion have been shown to have improved engraftment and regenerative capacities. Such cells can be generated by preconditioning them with exposure to an antioxidant. In this study we evaluated the effects of Tualang honey (TH), an antioxidant-containing honey, on human corneal epithelial progenitor (HCEP) cells in culture. Cytotoxicity, gene expression, migration, and cellular resistance to oxidative stress were evaluated. Immunofluorescence staining revealed that HCEP cells were holoclonal and expressed epithelial stem cell marker p63 without corneal cytokeratin 3. Cell viability remained unchanged after cells were cultured with 0.004, 0.04, and 0.4% TH in the medium, but it was significantly reduced when the concentration was increased to 3.33%. Cell migration, tested using scratch migration assay, was significantly enhanced when cells were cultured with TH at 0.04% and 0.4%. We also found that TH has hydrogen peroxide (H2O2) scavenging ability, although a trace level of H2O2 was detected in the honey in its native form. Preconditioning HCEP cells with 0.4% TH for 48 h showed better survival following H2O2-induced oxidative stress at 50 µM than untreated group, with a significantly lower number of dead cells (15.3 ± 0.4%) were observed compared to the untreated population (20.5 ± 0.9%, p<0.01). Both TH and ascorbic acid improved HCEP viability following induction of 100 µM H2O2, but the benefit was greater with TH treatment than with ascorbic acid. However, no significant advantage was demonstrated using 5-hydroxymethyl-2-furancarboxaldehyde, a compound that was found abundant in TH using GC/MS analysis. This suggests that the cellular anti-oxidative capacity in HCEP cells was augmented by native TH and was attributed to its antioxidant properties. In conclusion, TH possesses antioxidant properties and can improve cell migration and cellular resistance to oxidative stress in HCEP cells in vitro.
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics; ATP-Binding Cassette Transporters/metabolism
  16. Construction and characterization of a Burkholderia pseudomallei wzm deletion mutant
    Yuen CW, Ong EB, Mohamad S, Manaf UA, Najimudin N
    J Microbiol Biotechnol, 2012 Oct;22(10):1336-42.
    PMID: 23075783
    In Burkholderia pseudomallei, the pathogen that causes melioidosis, the gene cluster encoding the capsular polysaccharide, is located on chromosome 1. Among the 19 capsular genes in this cluster, wzm has not been thoroughly studied. To study the function of wzm, we generated a deletion mutant and compared it with the wild-type strain. The mutant produced less biofilm in minimal media and was more sensitive to desiccation and oxidative stress compared with the wild-type strain, indicating that wzm is involved in biofilm formation and membrane integrity. Scanning electron microscopy showed that the bacterial cells of the mutant strain have more defined surfaces with indentations, whereas cells of the wild-type strain do not.
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics*; ATP-Binding Cassette Transporters/metabolism
  17. Fulltext Reversing multidrug resistance in breast cancer cells by silencing ABC transporter genes with nanoparticle-facilitated delivery of target siRNAs
    Li YT, Chua MJ, Kunnath AP, Chowdhury EH
    Int J Nanomedicine, 2012;7:2473-81.
    PMID: 22701315 DOI: 10.2147/IJN.S30500
    Multidrug resistance, a major impediment to successful cancer chemotherapy, is the result of overexpression of ATP-binding cassette (ABC) transporters extruding internalized drugs. Silencing of ABC transporter gene expression with small interfering RNA (siRNA) could be an attractive approach to overcome multidrug resistance of cancer, although delivery of siRNA remains a major hurdle to fully exploit the potential of siRNA-based therapeutics. Recently, we have developed pH-sensitive carbonate apatite nanoparticles to efficiently carry and transport siRNA across the cell membrane, enabling knockdown of the cyclin B1 gene and consequential induction of apoptosis in synergy with anti-cancer drugs.
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics*; ATP-Binding Cassette Transporters/metabolism
  18. Role of UGT1A1*6, UGT1A1*28 and ABCG2 c.421C>A polymorphisms in irinotecan-induced neutropenia in Asian cancer patients
    Jada SR, Lim R, Wong CI, Shu X, Lee SC, Zhou Q, et al.
    Cancer Sci, 2007 Sep;98(9):1461-7.
    PMID: 17627617
    The objectives of the present study were (i) to study the pharmacogenetics of UGT1A1*6, UGT1A1*28 and ABCG2 c.421C>A in three distinct healthy Asian populations (Chinese, Malays and Indians), and (ii) to investigate the polygenic influence of these polymorphic variants in irinotecan-induced neutropenia in Asian cancer patients. Pharmacokinetic and pharmacogenetic analyses were done after administration of irinotecan as a 90-min intravenous infusion of 375 mg/m(2) once every 3 weeks (n = 45). Genotypic-phenotypic correlates showed a non-significant influence of UGT1A1*28 and ABCG2 c.421C>A polymorphisms on the pharmacokinetics of SN-38 (P > 0.05), as well as severity of neutropenia (P > 0.05). Significantly higher exposure levels to SN-38 (P = 0.018), lower relative extent of glucuronidation (REG; P = 0.006) and higher biliary index (BI; P = 0.003) were found in cancer patients homozygous for the UGT1A1*6 allele compared with patients harboring the reference genotype. The mean absolute neutrophil count (ANC) was 85% lower and the prevalence of grade 4 neutropenia (ANC < or = 500/microL) was 27% in patients homozygous for UGT1A1*6 compared with the reference group. Furthermore, the presence of the UGT1A1*6 allele was associated with an approximately 3-fold increased risk of developing severe grade 4 neutropenia compared with patients harboring the reference genotype. These exploratory findings suggest that homozygosity for UGT1A1*6 allele may be associated with altered SN-38 disposition and may increase the risk of severe neutropenia in Asian cancer patients, particularly in the Chinese cancer patients who comprised 80% (n = 36) of the patient population in the present study.
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics*; ATP-Binding Cassette Transporters/physiology
  19. Different serotypes of dengue viruses differently regulate the expression of the host cell antigen processing machinery
    Gan CS, Yusof R, Othman S
    Acta Trop, 2015 Sep;149:8-14.
    PMID: 25981524 DOI: 10.1016/j.actatropica.2015.05.005
    Dengue virus (DV) infection demonstrates an intriguing virus-induced intracellular membrane alteration that results in the augmentation of major histocompatibility complex (MHC) class I-restricted antigen presentation. As oppose to its biological function in attracting CD8(+) T-cells, this phenomenon appears to facilitate the immune evasion. However, the molecular events that attribute to the dysregulation of the antigen presenting mechanism (APM) by DV remain obscure. In this study, we aimed to characterize the host cell APM upon infection with all serotypes of whole DV. Cellular RNA were isolated from infected cells and the gene expressions of LMP2, LMP7, TAP1, TAP2, TAPBP, CALR, CANX, PDIA3, HLA-A and HLA-B were analyzed via quantitative PCR. The profiles of the gene expression were further validated. We showed that all four DV serotypes modulate host APM at the proteasomal level with DV2 showing the most prominent expression profile.
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics
  20. Fulltext Three cases of permanent neonatal diabetes mellitus: genotypes and management outcome
    Ooi HL, Wu LL
    Singapore Med J, 2012 Jul;53(7):e142-4.
    PMID: 22815030
    Neonatal diabetes mellitus (DM) is defined as insulin-requiring DM in the first six months of life. Unlike type 1 DM, it is a monogenic disorder resulting from a de novo mutation in the genes involved in the development of the pancreas, β-cell mass or secretory function. The majority of neonatal DM cases are caused by a heterozygous activating mutation in the KCNJ11 or ABCC8 genes that encode the Kir6.2 and SUR1 protein subunits, respectively, in the KATP channel. Sulphonylurea, a KATP channel inhibitor, can restore insulin secretion, hence offering an attractive alternative to insulin therapy. We report three cases of neonatal DM and their genetic mutations. Two patients were successfully switched over to sulphonylurea monotherapy with resultant improvement in the quality of life and a more stable blood glucose profile. Patients with neonatal DM should undergo genetic evaluation. For patients with KCNJ11 and ABCC8 gene mutation, oral sulphonylurea should be considered.
    Matched MeSH terms: ATP-Binding Cassette Transporters/genetics
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