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TT genotype of the methylenetetrahydrofolate reductase C677T polymorphism is an important determinant for homocysteine levels in multi-ethnic Malaysian ischaemic stroke patients

Mejia Mohamed EH, Tan KS, Ali JM, Mohamed Z

Ann Acad Med Singap, 2011 Apr;40(4):186-91.
PMID: 21678004

INTRODUCTION: The functional point mutation C677T in the methylenetetrahydrofolate reductase (MTHFR) gene, has been reported to contribute to hyperhomocysteinaemia which is a risk factor for atherothrombotic ischaemic strokes. This study evaluated the prevalence of the C677T polymorphism of the gene in Malaysian ischaemic stroke subjects of Malay, Chinese and Indian ethnicities, and its association with homocysteine levels (tHcy).
MATERIALS AND METHODS: A total of 292 subjects were recruited, comprising 150 ischaemic stroke patients and 142 control subjects who were age and sex matched. Plasma homocysteine, serum folate and vitamin B12 were measured in all subjects. Genotyping was carried out using PCR-RFLP.
RESULTS: The homocysteine levels were significantly higher (P = 0.001) in the stroke group (11.35 ± 2.75 μmol/L) compared to the control group (10.38 ± 2.79 μmol/L). The MTHFR C677T genotype distribution for the stroke group was 46%, 40% and 14%, respectively for CC, CT and TT genotypes and 59.9%, 33.8% and 6.3%, respectively for the control group. The genotype and allelic frequencies were significantly different between the 2 groups, with P = 0.02 and P = 0.004 respectively. No significant difference was seen in the genotype distribution inter-ethnically. An increasing tHcy was seen with every additional T allele, and the differences in the tHcy for the different genotypes were significant in both the control (P <0.001) and stroke groups (P <0.001).
CONCLUSION: This study shows that TT genotype of the methylenetetrahydrofolate reductase C677T polymorphic gene is an important determinant for homocysteine levels in Malaysian ischaemic stroke patients.
HMGB1: an overview of its versatile roles in the pathogenesis of colorectal cancer

Cheng KJ, Alshawsh MA, Mejia Mohamed EH, Thavagnanam S, Sinniah A, Ibrahim ZA

Cell Oncol (Dordr), 2020 Apr;43(2):177-193.
PMID: 31677065 DOI: 10.1007/s13402-019-00477-5

BACKGROUND: In recent years, the high mobility group box-1 (HMGB1) protein, a damage-associated molecular pattern (DAMP) molecule, has been found to play multifunctional roles in the pathogenesis of colorectal cancer. Although much attention has been given to the diagnostic and prognostic values of HMGB1 in colorectal cancer, the exact functional roles of the protein as well as the mechanistic pathways involved have remained poorly defined. This systematic review aims to discuss what is currently known about the roles of HMGB1 in colorectal cancer development, growth and progression, and to highlight critical areas for future investigations. To achieve this, the bibliographic databases Pubmed, Scopus, Web of Science and ScienceDirect were systematically screened for articles from inception till June 2018, which address associations of HMGB1 with colorectal cancer.
CONCLUSIONS: HMGB1 plays multiple roles in promoting the pathogenesis of colorectal cancer, despite a few contradicting studies. HMGB1 may differentially regulate disease-related processes, depending on the redox status of the protein in colorectal cancer. Binding of HMGB1 to various protein partners may alter the impact of HMGB1 on disease progression. As HMGB1 is heavily implicated in the pathogenesis of colorectal cancer, it is crucial to further improve our understanding of the functional roles of HMGB1 not only in colorectal cancer, but ultimately in all types of cancers.
Association of FTO, LEPR and MTHFR gene polymorphisms with metabolic syndrome in schizophrenia patients receiving antipsychotics

Roffeei SN, Mohamed Z, Reynolds GP, Said MA, Hatim A, Mohamed EH, et al.

Pharmacogenomics, 2014 Mar;15(4):477-85.
PMID: 24624915 DOI: 10.2217/pgs.13.220

The occurrence of metabolic syndrome (MS) in schizophrenia patients receiving long-term antipsychotics (APs) contributes to their high mortality rate. We aimed to determine whether genetic polymorphisms of identified candidate genes are associated with MS in our study population.
Fulltext Lack of association of ABCB1 haplotypes on five loci with response to treatment in epilepsy

Haerian BS, Lim KS, Mohamed EH, Tan HJ, Tan CT, Raymond AA, et al.

Seizure, 2011 Sep;20(7):546-53.
PMID: 21530324 DOI: 10.1016/j.seizure.2011.04.003

Approximately one third of newly treated epilepsy patients do not respond to antiepileptic drugs (AEDs). Overexpression of P-glycoprotein (P-gp) efflux transporter has been proposed to have a critical role in causing resistance to AEDs. P-gp is a product of the ATP-binding cassette subfamily B member 1 (ABCB1) gene. The purpose of this study was to investigate a possible link between ABCB1 rs3789243 C>T, C1236T, G2677T/A, rs6949448 C>T, and C3435T haplotypes with response to carbamazepine (CBZ) or sodium valproate (VPA) monotherapy in Malaysian epilepsy patients. No ABCB1 haplotype association was found with response to either CBZ or VPA monotherapy in the Chinese, Indian, and Malay patients. C3435 allele carriers of the Indian males with cryptogenic epilepsy were more prone to resistance to either CBZ or VPA than carriers of T allele. Moreover, rs3789243T allele carriers of Malay females with symptomatic epilepsy were more resistant to either CBZ or VPA than C allele carriers. Our findings suggest that the ABCB1 rs3789243 C>T, C1236T, G2677T/A, rs6949448 C>T, and C3435T haplotypes do not contribute to response to AED treatment in epilepsy.
Fulltext ABCB1 C3435T polymorphism and the risk of resistance to antiepileptic drugs in epilepsy: a systematic review and meta-analysis

Haerian BS, Roslan H, Raymond AA, Tan CT, Lim KS, Zulkifli SZ, et al.

Seizure, 2010 Jul;19(6):339-46.
PMID: 20605481 DOI: 10.1016/j.seizure.2010.05.004

The C3435T, a major allelic variant of the ABCB1 gene, is proposed to play a crucial role in drug-resistance in epilepsy. The C/C genotype carriers reportedly are at higher risk of pharmacoresistance to AEDs, but only in some studies. The hypothesis of the C-variant associated risk and resistance to antiepileptic drugs (AEDs) has been hampered by conflicting results from inadequate power in case-control studies. To assess the role of C3435T polymorphism in drug-resistance in epilepsy, a systematic review and meta-analysis was conducted.
Fulltext Lack of association of ABCB1 and PXR polymorphisms with response to treatment in epilepsy

Haerian BS, Lim KS, Mohamed EH, Tan HJ, Tan CT, Raymond AA, et al.

Seizure, 2011 Jun;20(5):387-94.
PMID: 21316268 DOI: 10.1016/j.seizure.2011.01.008

It is proposed that overexpression of P-glycoprotein (P-gp), encoded by the ABC subfamily B member 1 (ABCB1) gene, is involved in resistance to antiepileptic drugs (AEDs) in about 30% of patients with epilepsy. Genetic variation and haplotype patterns are population specific which may cause different phenotypes such as response to AEDs. Although several studies examined the link between the common polymorphisms in the ABCB1 gene with resistance to AEDs, the results have been conflicting. This controversy may be caused by the effect of some confounders such as ethnicity and polytherapy. Moreover, expression of the ABCB1 gene is under the control of pregnane X receptor (PXR). Evidence showed that PXR gene contribute to the response to treatment. The aim of this study was to assess the association of ABCB1 and PXR genetic polymorphisms with response to the carbamazepine (CBZ) or sodium valproate (VPA) monotherapy in epilepsy. Genotypes were assessed in 685 Chinese, Indian, and Malay epilepsy patients for ABCB1 (C1236T, G2677T, C3435T) and PXR (G7635A) polymorphisms. No association between these polymorphisms and their haplotypes, and interaction between them, with response to treatment was observed in the overall group or in the Chinese, Indian, and Malay subgroups. Our data showed that these polymorphisms may not contribute to the response to CBZ or VPA monotherapy treatment in epilepsy.
Fulltext Circulating cytokines and small molecules follow distinct expression patterns in acute myeloid leukaemia

Islam M, Mohamed EH, Esa E, Kamaluddin NR, Zain SM, Yusoff YM, et al.

Br. J. Cancer, 2017 Nov 07;117(10):1551-1556.
PMID: 28898234 DOI: 10.1038/bjc.2017.316

BACKGROUND: Although aberrant expression of cytokines and small molecules (analytes) is well documented in acute myeloid leukaemia (AML), their co-expression patterns are not yet identified. In addition, plasma baselines for some analytes that are biomarkers for other cancers have not been previously reported in AML.
METHODS: We used multiplex array technology to simultaneously detect and quantify 32 plasma analyte (22 reported analytes and 10 novel analytes) levels in 38 patients.
RESULTS: In our study, 16 analytes are found to be significantly deregulated (13 higher, 3 lower, Mann-Whitney U-test, P-value <0.005), where 5 of them have never been reported before in AML. We predicted a seven-analyte-containing multiplex panel for diagnosis of AML and, among them, MIF could be a possible therapeutic target. In addition, we observed that circulating analytes show five co-expression signatures.
CONCLUSIONS: Circulating analyte expression in AML significantly differs from normal, and follow distinct expression patterns.
Insights into the molecular mechanisms and signalling pathways of epithelial to mesenchymal transition (EMT) in colorectal cancer: A systematic review and bioinformatic analysis of gene expression

Azizan S, Cheng KJ, Mejia Mohamed EH, Ibrahim K, Faruqu FN, Vellasamy KM, et al.

Gene, 2024 Feb 20;896:148057.
PMID: 38043836 DOI: 10.1016/j.gene.2023.148057

Colorectal cancer (CRC) is ranked as the second leading cause of mortality worldwide, mainly due to metastasis. Epithelial to mesenchymal transition (EMT) is a complex cellular process that drives CRC metastasis, regulated by changes in EMT-associated gene expression. However, while numerous genes have been identified as EMT regulators through various in vivo and in vitro studies, little is known about the genes that are differentially expressed in CRC tumour tissue and their signalling pathway in regulating EMT. Using an integration of systematic search and bioinformatic analysis, gene expression profiles of CRC tumour tissues were compared to non-tumour adjacent tissues to identify differentially expressed genes (DEGs), followed by performing systematic review on common identified DEGs. Fifty-eight common DEGs were identified from the analysis of 82 tumour tissue samples obtained from four gene expression datasets (NCBI GEO). These DEGS were then systematically searched for their roles in modulating EMT in CRC based on previously published studies. Following this, 10 common DEGs (CXCL1, CXCL8, MMP1, MMP3, MMP7, TACSTD2, VIP, HPGD, ABCG2, CLCA4) were included in this study and subsequently subjected to further bioinformatic analysis. Their roles and functions in modulating EMT in CRC were discussed in this review. This study enhances our understanding of the molecular mechanisms underlying EMT and uncovers potential candidate genes and pathways that could be targeted in CRC.
Association between ABCB1 polymorphism and response to sodium valproate treatment in Malaysian epilepsy patients

Haerian BS, Lim KS, Tan HJ, Mohamed EH, Tan CT, Raymond AA, et al.

Epileptic Disord, 2011 Mar;13(1):65-75.
PMID: 21388909 DOI: 10.1684/epd.2011.0419

Over-expression of P-glycoprotein, encoded by the ABCB1 gene, is proposed to be involved in resistance to antiepileptic drugs in about 30% of patients with epilepsy. Here, we investigated the possible association between ABCB1 polymorphisms and sodium valproate (VPA) treatment in Malaysian epilepsy patients. Genotypes were assessed in 249 drug-resistant and 256 drug-responsive Malaysian patients for C1236T, G2677T/A, and C 5T polymorphisms in the ABCB1 gene. No genotypes, alleles, or haplotypes were associated with the response to VPA in either the overall group or Chinese, Indian, and Malay subgroups. Our data suggest that C1236T, G2677T/A, and C3435T polymorphisms in the ABCB1 gene do not contribute to the response to VPA in patients with epilepsy.