Displaying publications 41 - 60 of 69 in total

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  1. Sulaiman SA, Abu N, Ab-Mutalib NS, Low TY, Jamal R
    Future Oncol, 2019 Aug;15(22):2603-2617.
    PMID: 31339048 DOI: 10.2217/fon-2018-0909
    Aim: Micro and macro vascular invasion (VI) are known as independent predictors of tumor recurrence and poor survival after surgical treatment of hepatocellular carcinoma (HCC). Here, we aimed to re-analyze The Cancer Genome Atlas of liver hepatocellular carcinoma datasets to identify the VI-expression signatures. Materials & methods: We filtered The Cancer Genome Atlas liver hepatocellular carcinoma (LIHC) datasets into three groups: no VI (NVI = 198); micro VI (MIVI = 89) and macro VI (MAVI = 16). We performed differential gene expression, methylation and microRNA analyses. Results & conclusion: We identified 12 differentially expressed genes and 55 differentially methylated genes in MAVI compared with no VI. The GPD1L gene appeared in all of the comparative analyses. Higher GPD1L expression was associated with VI and poor outcomes in the HCC patients.
  2. Abu N, Othman N, Ab Razak NS, Bakarurraini NAAR, Nasir SN, Soh JEC, et al.
    Front Cell Dev Biol, 2020;8:564648.
    PMID: 33324632 DOI: 10.3389/fcell.2020.564648
    Colorectal cancer (CRC) is one of the most widely diagnosed cancers worldwide. It has been shown that the body-mass index (BMI) of the patients could influence the tumor microenvironment, treatment response, and overall survival rates. Nevertheless, the mechanism on how BMI affects the tumorigenesis process, particularly the tumor microenvironment is still elusive. Herein, we postulate that extracellular vesicles (EVs) from CRC patients and non-CRC volunteers with different BMI could affect immune cells differently, in CD8 T cells particularly. We isolated the EVs from the archived serum of CRC patients with high and low BMI, as well as healthy controls with similar BMI status. The EVs were further characterized via electron microscopy, western blot and dynamic light scattering. Then, functional analysis was performed on CD8 T cells including apoptosis, cell proliferation, gene expression profiling and cytokine release upon co-incubation with the different EVs. Our results suggest that CRC-derived EVs were able to regulate the CD8 T cells. In some assays, low BMI EVs were functionally different than high BMI EVs. This study highlights the possible difference in the regulatory mechanism of cancer patients-derived EVs, especially on CD8 T cells.
  3. Abu N, Othman N, W Hon K, Nazarie WF, Jamal R
    Biomark Med, 2020 05;14(7):525-537.
    PMID: 32462912 DOI: 10.2217/bmm-2019-0241
    Background: Finding a new target or a new drug to overcome chemoresistance is difficult due to the heterogenous nature of cancer. Meta-analysis was performed to combine the analysis of different microarray studies to get a robust discovery. Materials & methods: Herein, we analyzed three microarray datasets on combination of folinic acid, fluorouracil, and oxaliplatin drugs (FOLFOX) resistance that fit our inclusion/exclusion criteria and performed a meta-analysis using the OmiCC system. Results: We identified several deregulated genes and we discovered HNF4A as a hub gene. We performed functional validation and observed that by targeting HNF4A, HCT116 cells were more sensitive toward both oxaliplatin and 5-fluorouracil significantly. Conclusion: Our findings show that HNF4A could be a potential target in overcoming FOLFOX chemoresistance in colorectal cancer.
  4. Abu N, Jamal R
    Front Physiol, 2016;7:355.
    PMID: 27588005 DOI: 10.3389/fphys.2016.00355
    The interest in circular RNAs has resurfaced in the past few years. What was considered as "junk" for nearly two decades is now one of the most interesting molecules. Circular RNAs are non-coding RNAs that are formed by back-splicing events and have covalently closed loops with no poly-adenylated tails. The regulation of circular RNAs is distinctive and they are selectively abundant in different types of tissues. Based on the current knowledge of circular RNAs, these molecules have the potential to be the "next big thing" especially as biomarkers for different diseases. This mini-review attempts to concisely look at the biology of circular RNAs, the putative functional activities, the prevalence of circular RNAs, and the possible role of circular RNA as biomarkers for diagnosis or measuring drug response.
  5. Hon KW, Abu N, Ab Mutalib NS, Jamal R
    Front Pharmacol, 2018;9:846.
    PMID: 30127741 DOI: 10.3389/fphar.2018.00846
    Chemotherapy is one of the options for cancer treatment. FOLFOX is one of the widely used chemotherapeutic regimens used to treat primarily colorectal cancer and other cancers as well. However, the emergence of chemo-resistance clones during cancer treatment has become a critical challenge in the clinical setting. It is crucial to identify the potential biomarkers and therapeutics targets which could lead to an improvement in the success rate of the proposed therapies. Since non-coding RNAs have been known to be important players in the cellular system, the interest in their functional roles has intensified. Non-coding RNAs (ncRNAs) as regulators at the post-transcriptional level could be very promising to provide insights in overcoming chemo-resistance to FOLFOX. Hence, this mini review attempts to summarize the potential of ncRNAs correlating with chemo-sensitivity/resistance to FOLFOX.
  6. Sulaiman SA, Abdul Murad NA, Mohamad Hanif EA, Abu N, Jamal R
    Adv Exp Med Biol, 2018 9 28;1087:357-370.
    PMID: 30259380 DOI: 10.1007/978-981-13-1426-1_28
    circRNAs have emerged as one of the key regulators in many cellular mechanisms and pathogenesis of diseases. However, with the limited knowledge and current technologies for circRNA investigations, there are several challenges that need to be addressed for. These include challenges in understanding the regulation of circRNA biogenesis, experimental designs, and sample preparations to characterize the circRNAs in diseases as well as the bioinformatics pipelines and algorithms. In this chapter, we discussed the above challenges and possible strategies to overcome those limitations. We also addressed the differences between the existing applications and technologies to study the circRNAs in diseases. By addressing these challenges, further understanding of circRNAs roles and regulations as well as the discovery of novel circRNAs could be achieved.
  7. Chi Soh JE, Abu N, Jamal R
    Immunotherapy, 2018 09;10(12):1093-1104.
    PMID: 30185136 DOI: 10.2217/imt-2018-0044
    The identification of cancer testis antigens (CTAs) has been an important finding in the search of potential targets for cancer immunotherapy. CTA is one of the subfamilies of the large tumor-associated antigens groups. It is aberrantly expressed in various types of human tumors but is absent in normal tissues except for the testis and placenta. This CTAs-restricted pattern of expression in human malignancies together with its potential immunogenic properties, has stirred the interest of many researchers to use CTAs as one of the ideal targets in cancer immunotherapy. To date, multiple studies have shown that CTAs-based vaccines can elicit clinical and immunological responses in different tumors, including colorectal cancer (CRC). This review details our current understanding of CTAs and CRC in regard to the expression and immunological responses as well as some of the critical hurdles in CTAs-based immunotherapy.
  8. Abu N, Hon KW, Jeyaraman S, Jamal R
    Future Oncol, 2018 Dec;14(29):3085-3095.
    PMID: 30468082 DOI: 10.2217/fon-2018-0303
    Since its discovery, cisplatin has become the key drug in chemotherapy for cancers. Nevertheless, chemoresistance in cancers has become an impediment in using cisplatin for cancer treatment. The resistance toward cisplatin is multifaceted as it involves multiple cellular pathways. Ever since the knowledge of long noncoding RNAs as modulators of various molecular pathways came to light, the interest in the biological function of lncRNAs as biomarkers has increased dramatically. Numerous studies have reported the link between the dysregulation of lncRNAs and drug resistance in cancers. More importantly, several lncRNAs were found to be vital in regulating cisplatin resistance. Therefore, this review summarizes the recent efforts in linking between cisplatin resistance and different types of lncRNAs.
  9. Soon BH, Abu N, Abdul Murad NA, Then SM, Abu Bakar A, Fadzil F, et al.
    Per Med, 2022 01;19(1):25-39.
    PMID: 34873928 DOI: 10.2217/pme-2021-0033
    Aim: Mitochondrial DNA (mtDNA) alterations play an important role in the multistep processes of cancer development. Gliomas are among the most diagnosed brain cancer. The relationship between mtDNA alterations and different grades of gliomas are still elusive. This study aimed to elucidate the profile of somatic mtDNA mutations in different grades of gliomas and correlate it with clinical phenotype. Materials & methods: Forty histopathologically confirmed glioma tissue samples and their matched blood were collected and subjected for mtDNA sequencing. Results & conclusion: About 75% of the gliomas harbored at least one somatic mutation in the mtDNA gene, and 45% of these mutations were pathogenic. Mutations were scattered across the mtDNA genome, and the commonest nonsynonymous mutations were located at complex I and IV of the mitochondrial respiratory chain. These findings may have implication for future research to determine the mitochondrial energetics and its downstream metabolomics on gliomas.
  10. Abdul SN, Ab Mutalib NS, Sean KS, Syafruddin SE, Ishak M, Sagap I, et al.
    Front Pharmacol, 2017;8:465.
    PMID: 28769798 DOI: 10.3389/fphar.2017.00465
    Despite global progress in research, improved screening and refined treatment strategies, colorectal cancer (CRC) remains as the third most common malignancy. As each type of cancer is different and exhibits unique alteration patterns, identifying and characterizing gene alterations in CRC that may serve as biomarkers might help to improve diagnosis, prognosis and predict potential response to therapy. With the emergence of next generation sequencing technologies (NGS), it is now possible to extensively and rapidly identify the gene profile of individual tumors. In this study, we aimed to identify actionable somatic alterations in Dukes' B and C in CRC via NGS. Targeted sequencing of 409 cancer-related genes using the Ion Ampliseq(TM) Comprehensive Cancer Panel was performed on genomic DNA obtained from paired fresh frozen tissues, cancer and normal, of Dukes' B (n = 10) and Dukes' C (n = 9) CRC. The sequencing results were analyzed using Torrent Suite, annotated using ANNOVAR and validated using Sanger sequencing. A total of 141 somatic non-synonymous sequence variations were identified in 86 genes. Among these, 64 variants (45%) were predicted to be deleterious, 38 variants (27%) possibly deleterious while the other 39 variants (28%) have low or neutral protein impact. Seventeen genes have alterations with frequencies of ≥10% in the patient cohort and with 14 overlapped genes in both Dukes' B and C. The adenomatous polyposis coli gene (APC) was the most frequently altered gene in both groups (n = 6 in Dukes' B and C). In addition, TP53 was more frequently altered in Dukes' C (n = 7) compared to Dukes' B (n = 4). Ten variants in APC, namely p.R283(∗), p.N778fs, p.R805(∗), p.Y935fs, p.E941fs, p.E1057(∗), p.I1401fs, p.Q1378(∗), p.E1379(∗), and p.A1485fs were predicted to be driver variants. APC remains as the most frequently altered gene in the intermediate stages of CRC. Wnt signaling pathway is the major affected pathway followed by P53, RAS, TGF-β, and PI3K signaling. We reported the alteration profiles in each of the patient which has the potential to affect the clinical decision. We believe that this study will add further to the understanding of CRC molecular landscape.
  11. Nasir SN, Abu N, Ab Mutalib NS, Ishak M, Sagap I, Mazlan L, et al.
    Clin Transl Oncol, 2018 Jun;20(6):775-784.
    PMID: 29098557 DOI: 10.1007/s12094-017-1788-x
    PURPOSE: Colorectal cancer (CRC) is one of the most widely diagnosed cancers in men and women worldwide. With the advancement of next-generation sequencing technologies, many studies have highlighted the involvement of long non-coding RNAs (lncRNAs) in cancer development. Growing evidence demonstrates that lncRNAs play crucial roles in regulating gene and protein expression and are involved in various cancers, including CRC. The field of lncRNAs is still relatively new and a lot of novel lncRNAs have been discovered, but their functional roles are yet to be elucidated. This study aims to characterize the expression and functional roles of a novel lncRNA in CRC.

    METHOD: Several methods were employed to assess the function of LOC285629 such as gene silencing, qPCR, proliferation assay, BrdU assay, transwell migration assay, ELISA and protein profiler.

    RESULTS: Via in silico analyses, we identified significant downregulation of LOC285629, a novel lncRNA, across CRC stages. LOC285629 expression was significantly downregulated in advanced stages (Stage III and IV) compared to Stage I (Kruskal-Wallis Test; p = 0.0093). Further in-house validation showed that the expression of LOC285629 was upregulated in colorectal cancer tissues and cell lines compared to the normal counterparts, but was downregulated in advanced stages. By targeting LOC285629, the viability, proliferative abilities, invasiveness and resistance of colorectal cancer cells towards 5-fluorouracil were reduced. It was also discovered that LOC285629 may regulate cancer progression by targeting several different proteins, namely survivin, BCL-xL, progranulin, PDGF-AA, enolase 2 and p70S6 K.

    CONCLUSION: Our findings suggest that LOC285629 may be further developed as a potential therapeutic target for CRC treatment.

  12. Hon KW, Abu N, Ab Mutalib NS, Jamal R
    Front Pharmacol, 2017;8:583.
    PMID: 28894420 DOI: 10.3389/fphar.2017.00583
    The number of colorectal cancer (CRC) cases have increased gradually year by year. In fact, CRC is one of the most widely diagnosed cancer in men and women today. This disease is usually diagnosed at a later stage of the development, and by then, the chance of survival has declined significantly. Even though substantial progress has been made in understanding the basic molecular mechanism of CRC, there is still a lack of understanding in using the available information for diagnosing CRC effectively. Liquid biopsies are minimally invasive and have become the epitome of a good screening source for stage-specific diagnosis, measuring drug response and severity of the disease. There are various circulating entities that can be found in biological fluids, and among them, exosomes, have been gaining considerable attention. Exosomes can be found in almost all biological fluids including serum, urine, saliva, and breast milk. Furthermore, exosomes carry valuable molecular information such as proteins and nucleic acids that directly reflects the source of the cells. Nevertheless, the inconsistent yield and isolation process and the difficulty in obtaining pure exosomes have become major obstacles that need to be addressed. The potential usage of exosomes as biomarkers have not been fully validated and explored yet. This review attempts to uncover the potential molecules that can be derived from CRC-exosomes as promising biomarkers or molecular targets for effective diagnosing of CRC.
  13. Mohd Yunos RI, Ab Mutalib NS, Khoo JS, Saidin S, Ishak M, Syafruddin SE, et al.
    Front Mol Biosci, 2022;9:997747.
    PMID: 36866106 DOI: 10.3389/fmolb.2022.997747
    The incidences of colorectal cancer (CRC) are continuously increasing in some areas of the world, including Malaysia. In this study, we aimed to characterize the landscape of somatic mutations using the whole-genome sequencing approach and identify druggable somatic mutations specific to Malaysian patients. Whole-genome sequencing was performed on the genomic DNA obtained from 50 Malaysian CRC patients' tissues. We discovered the top significantly mutated genes were APC, TP53, KRAS, TCF7L2 and ACVR2A. Four novel, non-synonymous variants were identified in three genes, which were KDM4E, MUC16 and POTED. At least one druggable somatic alteration was identified in 88% of our patients. Among them were two frameshift mutations in RNF43 (G156fs and P192fs) predicted to have responsive effects against the Wnt pathway inhibitor. We found that the exogenous expression of this RNF43 mutation in CRC cells resulted in increased cell proliferation and sensitivity against LGK974 drug treatment and G1 cell cycle arrest. In conclusion, this study uncovered our local CRC patients' genomic landscape and druggable alterations. It also highlighted the role of specific RNF43 frameshift mutations, which unveil the potential of an alternative treatment targeting the Wnt/β-Catenin signalling pathway and could be beneficial, especially to Malaysian CRC patients.
  14. Suhaimi SS, Ab Mutalib NS, Khor SS, Zain RRM, Syafruddin SE, Abu N, et al.
    Front Pharmacol, 2018;9:750.
    PMID: 30057548 DOI: 10.3389/fphar.2018.00750
    Endometrioid endometrial cancer (EEC) is the commonest form of endometrial cancer and can be divided into estrogen receptor (ER) positive and negative subtypes. The mutational profiles of EEC have been shown to aid in tailoring treatment; however, little is known about the differences between the gene mutation profiles between these two subtypes. This study aims to investigate the gene mutation profile in ER positive and negative EEC, and to further elucidate the role of WHSC1 mutations in this cancer. EEC and normal endometrial tissues were obtained from 29 patients and subjected to next-generation sequencing (NGS) using Ion Ampliseq Comprehensive Cancer PanelTM targeting 409 cancer related. A total of 741 non-synonymous alterations were identified from 272 genes in ER positive subtype while 448 non-synonymous variants were identified from 221 genes in ER negative subtype. PTEN is the most frequently altered gene in ER positive subtype (64%, 7/11) while ARID1A is the most frequently altered gene in ER negative subtype (50%, 4/8). We also identified alterations in ERRB3 (36%, 4/11), GNAS (36%, 4/11), and WHSC1 (27%, 3/11) in the ER positive subtype. WHSC1 R1126H and L1268P were shown to significantly increase cell viability, proliferation, migration, and survival. In addition, reduction in ER expression sensitized EEC-1 cell with WHSC1 L1268P mutant to Fulvestrant treatment. We revealed the mutational spectra of ER positive and ER negative EEC that could lead to better understanding of the biological mechanisms of endometrial cancer and may ultimately result in improvement of treatment options and patient prognosis.
  15. Ali NM, Akhtar MN, Ky H, Lim KL, Abu N, Zareen S, et al.
    Drug Des Devel Ther, 2016;10:1897-907.
    PMID: 27358555 DOI: 10.2147/DDDT.S102164
    Known as naturally occurring biologically active compounds, flavokawain A and B are the leading chalcones that possess anticancer properties. Another flavokawain derivative, (E)-1-(2'-Hydroxy-4',6'-dimethoxyphenyl)-3-(4-methylthio)phenyl)prop-2-ene-1-one (FLS) was characterized with (1)H-nuclear magnetic resonance, electron-impact mas spectrometry, infrared spectroscopy, and ultraviolet ((1)H NMR, EI-MS, IR, and UV) spectroscopic techniques. FLS cytotoxic efficacy against human cancer cells (MCF-7, MDA-MB-231, and MCF-10A) resulted in the reduction of IC50 values in a time- and dose-dependent mode with high specificity on MCF-7 (IC50 of 36 μM at 48 hours) against normal breast cell MCF-10A (no IC50 detected up to 180 μM at 72 hours). Light, scanning electron, and fluorescent microscopic analysis of MCF-7 cells treated with 36 μM of FLS displayed cell shrinkage, apoptotic body, and DNA fragmentation. Additionally, induction of G2/M cell arrest within 24 hours and apoptosis at subsequent time points was discovered via flow cytometry analysis. The roles of PLK-1, Wee-1, and phosphorylation of CDC-2 in G2/M arrest and proapoptotic factors (Bax, caspase 9, and p53) in promotion of apoptosis of FLS against MCF-7 cells were discovered using fluorometric, quantitative real-time polymerase chain reaction, and Western blot analysis. Interestingly, the presence of SCH3 (thiomethyl group) on ring B structure contributed to the selective cytotoxicity against MCF-7 cells compared to other chalcones, flavokawain A and B. Overall, our data suggest potential therapeutic value for flavokawain derivative FLS to be further developed as a new anticancer drug.
  16. Yeap SK, Abu N, Akthar N, Ho WY, Ky H, Tan SW, et al.
    Integr Cancer Ther, 2017 09;16(3):373-384.
    PMID: 27458249 DOI: 10.1177/1534735416660383
    Flavokawain B (FKB) is known to possess promising anticancer abilities. This is demonstrated in various cancer cell lines including HeLa cells. Cervical cancer is among the most widely diagnosed cancer among women today. Though FKB has been shown to be effective in treating cancer cells, the exact molecular mechanism is still unknown. This study is aimed at understanding the effects of FKB on HeLa cells using a microarray-based mRNA expression profiling and proteome profiling of stress-related proteins. The results of this study suggest that FKB induced cell death through p21-mediated cell cycle arrest and activation of p38. However, concurrent activation of antioxidant-related pathways and iron sequestration pathway followed by activation of ER-resident stress proteins clearly indicate that FKB failed to induce apoptosis in HeLa cells via oxidative stress. This effect implies that the protection of HeLa cells by FKB from H2O2-induced cell death is via neutralization of reactive oxygen species.
  17. Yeoh Y, Low TY, Abu N, Lee PY
    PeerJ, 2021;9:e12338.
    PMID: 34733591 DOI: 10.7717/peerj.12338
    Resistance to anti-cancer treatments is a critical and widespread health issue that has brought serious impacts on lives, the economy and public policies. Mounting research has suggested that a selected spectrum of patients with advanced colorectal cancer (CRC) tend to respond poorly to both chemotherapeutic and targeted therapeutic regimens. Drug resistance in tumours can occur in an intrinsic or acquired manner, rendering cancer cells insensitive to the treatment of anti-cancer therapies. Multiple factors have been associated with drug resistance. The most well-established factors are the emergence of cancer stem cell-like properties and overexpression of ABC transporters that mediate drug efflux. Besides, there is emerging evidence that signalling pathways that modulate cell survival and drug metabolism play major roles in the maintenance of multidrug resistance in CRC. This article reviews drug resistance in CRC as a result of alterations in the MAPK, PI3K/PKB, Wnt/β-catenin and Notch pathways.
  18. Sood M, Mohd Zain Z, Abu NA, Chee SC, Mohd Nor NS
    Med J Malaysia, 2019 02;74(1):40-44.
    PMID: 30846661
    INTRODUCTION: Some anecdotal reports suggest that maternal colonisation with Acinetobacter baumannii during pregnancy is associated with adverse maternal and neonatal effects, including preterm premature rupture of membrane (PPROM). The objective of this study was to compare the maternal and neonatal effects of A. baumannii colonisation in cases with PPROM and those with spontaneous onset of labour at term.

    METHODS: The recruitment of participants' was carried out at Selayang Hospital, Selangor, Malaysia. Vaginal swabs were prospectively taken from 104 patients of PPROM and 111 with spontaneous onset of labour at term. Swabs were also taken from the axillae and ears of their babies. These swabs were cultured to isolate A. baumannii. Maternal and neonatal adverse outcomes were documented.

    RESULTS: Sixteen mothers were A. baumannii positive, eight from each group respectively. None of the cases developed chorioamnionitis or sepsis. Those positive were four cases of PPROM and two babies of term labour. None of the babies developed sepsis.

    CONCLUSIONS: This study does not support the suggestion that A. baumannii colonisation during pregnancy is associated with adverse maternal and neonatal outcomes.

  19. Abu N, Rus Bakarurraini NAA, Nasir SN
    Front Immunol, 2021;12:740548.
    PMID: 34721407 DOI: 10.3389/fimmu.2021.740548
    Certain cancer therapy has been shown to induce immunogenic cell death in cancer cells and may promote tumor progression instead. The external stress or stimuli may induce cell death and contribute toward the secretion of pro inflammatory molecules. The release of damage-associated molecular patterns (DAMPs) upon induction of therapy or cell death has been shown to induce an inflammatory response. Nevertheless, the mechanism as to how the DAMPs are released and engage in such activity needs further in-depth investigation. Interestingly, some studies have shown that DAMPs can be released through extracellular vesicles (EVs) and can bind to receptors such as toll-like receptors (TCRs). Ample pre-clinical studies have shown that cancer-derived EVs are able to modulate immune responses within the tumor microenvironment. However, the information on the presence of such DAMPs within EVs is still elusive. Therefore, this mini-review attempts to summarize and appraise studies that have shown the presence of DAMPs within cancer-EVs and how it affects the downstream cellular process.
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