Displaying publications 161 - 180 of 516 in total

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  1. Voon YL, Ahmad M, Wong PF, Husaini R, Ng WT, Leong CO, et al.
    Oncol Rep, 2015 Oct;34(4):1692-700.
    PMID: 26252575 DOI: 10.3892/or.2015.4177
    The small-molecule inhibitor of p53-Mdm2 interaction, Nutlin-3, is known to be effective against cancers expressing wild-type (wt) p53. p53 mutations are rare in nasopharyngeal carcinoma (NPC), hence targeting disruption of p53-Mdm2 interaction to reactivate p53 may offer a promising therapeutic strategy for NPC. In the present study, the effects of Nutlin-3 alone or in combination with cisplatin, a standard chemotherapeutic agent, were tested on C666-1 cells, an Epstein-Barr virus (EBV)-positive NPC cell line bearing wt p53. Treatment with Nutlin-3 activated the p53 pathway and sensitized NPC cells to the cytotoxic effects of cisplatin. The combined treatment also markedly suppressed soft agar colony growth formation and increased apoptosis of NPC cells. The effect of Nutlin-3 on NPC cells was inhibited by knockdown of p53, suggesting that its effect was p53-dependent. Extended treatment with increasing concentrations of Nutlin-3 did not result in emergence of p53 mutations in the C666-1 cells. Collectively, the present study revealed supportive evidence of the effectiveness of combining cisplatin and Nutlin-3 as a potential therapy against NPC.
  2. Yap LF, Ahmad M, Zabidi MM, Chu TL, Chai SJ, Lee HM, et al.
    Int J Oncol, 2014 May;44(5):1774-80.
    PMID: 24626628 DOI: 10.3892/ijo.2014.2342
    The molecular events that drive the progression of Epstein-Barr virus (EBV)-associated nasopharyngeal carcinoma (NPC) are still to be elucidated. Here, we report for the first time the pathogenic significance of an NPC-associated gene, wingless-type MMTV integration site family, member 5A (WNT5A) and the contribution of EBV to its expression. WNT5A is a representative Wnt protein that activates non-canonical Wnt signalling. With regard to its role in carcinogenesis, there is conflicting evidence as to whether WNT5A has a tumour-promoting or tumour-suppressive role. We show that WNT5A is upregulated in primary NPC tissue samples. We also demonstrate that WNT5A expression was dramatically increased in NPC cell lines expressing the EBV-encoded LMP2A gene, suggesting that this EBV-encoded latent gene is responsible for upregulating WNT5A in NPC. In addition, in vitro WNT5A overexpression promotes the proliferation, migration and invasion of NPC cells. Our results not only reveal pro-tumorigenic effects of WNT5A in NPC but also suggest that WNT5A could be an important therapeutic target in patients with EBV-associated disease.
  3. Teow SY, Liew K, Che Mat MF, Marzuki M, Abdul Aziz N, Chu TL, et al.
    BMC Biotechnol, 2019 06 14;19(1):34.
    PMID: 31200673 DOI: 10.1186/s12896-019-0528-4
    BACKGROUND: In vitro modelling of cancer cells is becoming more complex due to prevailing evidence of intimate interactions between cancer cells and their surrounding stroma. A co-culture system which consists of more than one cell type is physiologically more relevant and thus, could serve as a useful model for various biological studies. An assay that specifically detects the phenotypic changes of cancer cells in a multi-cellular system is lacking for nasopharyngeal carcinoma (NPC).

    RESULTS: Here, we describe a luciferase/luciferin (XenoLuc) assay that could specifically measure changes in the proliferation of cancer cells in the co-culture system using two modified NPC patient-derived tumour xenograft (PDTXs) cells: Xeno284-gfp-luc2 and XenoB110-gfp-luc2. Through this assay, we are able to show that the growth of NPC xenograft cells in both two-dimensional (2D) and three-dimensional (3D) models was enhanced when co-cultured with normal human dermal fibroblasts (NHDFs). In addition, potential applications of this assay in in vitro drug or inhibitor screening experiments are also illustrated.

    CONCLUSIONS: XenoLuc assay is specific, sensitive, rapid and cost-effective for measuring the growth of luciferase-expressing cells in a co- or multiple-culture system. This assay may also be adapted for tumour microenvironment studies as well as drug screening experiments in more complex 3D co-culture systems.

  4. Hoe SLL, Tan LP, Abdul Aziz N, Liew K, Teow SY, Abdul Razak FR, et al.
    Sci Rep, 2017 09 28;7(1):12372.
    PMID: 28959019 DOI: 10.1038/s41598-017-12045-8
    Subpopulations of nasopharyngeal carcinoma (NPC) contain cells with differential tumourigenic properties. Our study evaluates the tumourigenic potential of CD24, CD44, EpCAM and combination of EpCAM/CD44 cells in NPC. CD44br and EpCAMbr cells enriched for higher S-phase cell content, faster-growing tumourigenic cells leading to tumours with larger volume and higher mitotic figures. Although CD44br and EpCAMbr cells significantly enriched for tumour-initiating cells (TICs), all cells could retain self-renewal property for at least four generations. Compared to CD44 marker alone, EpCAM/CD44dbr marker did not enhance for cells with faster-growing ability or higher TIC frequency. Cells expressing high CD44 or EpCAM had lower KLF4 and p21 in NPC subpopulations. KLF4-overexpressed EpCAMbr cells had slower growth while Kenpaullone inhibition of KLF4 transcription increased in vitro cell proliferation. Compared to non-NPC, NPC specimens had increased expression of EPCAM, of which tumours from advanced stage of NPC had higher expression. Together, our study provides evidence that EpCAM is a potentially important marker in NPC.
  5. Ahmad M, Suhaimi SN, Chu TL, Abdul Aziz N, Mohd Kornain NK, Samiulla DS, et al.
    PLoS One, 2018;13(1):e0191295.
    PMID: 29329342 DOI: 10.1371/journal.pone.0191295
    Copper(II) ternary complex, [Cu(phen)(C-dmg)(H2O)]NO3 was evaluated against a panel of cell lines, tested for in vivo efficacy in nasopharyngeal carcinoma xenograft models as well as for toxicity in NOD scid gamma mice. The Cu(II) complex displayed broad spectrum cytotoxicity against multiple cancer types, including lung, colon, central nervous system, melanoma, ovarian, and prostate cancer cell lines in the NCI-60 panel. The Cu(II) complex did not cause significant induction of cytochrome P450 (CYP) 3A and 1A enzymes but moderately inhibited CYP isoforms 1A2, 2C9, 2C19, 2D6, 2B6, 2C8 and 3A4. The complex significantly inhibited tumor growth in nasopharyngeal carcinoma xenograft bearing mice models at doses which were well tolerated without causing significant or permanent toxic side effects. However, higher doses which resulted in better inhibition of tumor growth also resulted in toxicity.
  6. Hoe SL, Tan LP, Jamal J, Peh SC, Ng CC, Zhang WC, et al.
    Cancer Cell Int, 2014;14(1):101.
    PMID: 25317078 DOI: 10.1186/s12935-014-0101-0
    Side population (SP) assay identifies cells with dye/drug extrusion ability, a characteristic of stem cells. Here, we determined if SP cells exist in a verified cell line originating from recurrent nasopharyngeal carcinoma (NPC) and a xenograft established from recurrent metastatic NPC. These cells were evaluated for stem-like properties via functional assays as well as for tumourigenicity.
  7. Daker M, Ahmad M, Khoo AS
    Cancer Cell Int, 2012;12(1):34.
    PMID: 22809533
    Nasopharyngeal carcinoma (NPC) is a unique tumour of epithelial origin with a distinct geographical distribution, genetic predisposition and environmental as well as dietary influence as aetiological factors. Standard NPC treatment regimes, such as radiotherapy and concurrent chemotherapy with cytotoxic drugs, can produce undesirable complications often associated with significant toxicity. Here, we report the effects of a widely distributed flavonoid, quercetin, on cell proliferation, apoptosis and cell cycle arrest. The effects of combining quercetin and cisplatin on human NPC cells were explored.
  8. Daker M, Yeo JT, Bakar N, Abdul Rahman AS, Ahmad M, Yeo TC, et al.
    Exp Ther Med, 2016 Jun;11(6):2117-2126.
    PMID: 27284293
    Nasopharyngeal carcinoma (NPC) is a type of tumour that arises from the epithelial cells that line the surface of the nasopharynx. NPC is treated with radiotherapy and cytotoxic chemotherapeutic drugs such as cisplatin and 5-fluorouracil. However, current strategies are often associated with potential toxicities. This has prompted efforts to identify alternative methods of treatment. The present study aimed to investigate silvestrol and episilvestrol-mediated inhibition of cell proliferation in human NPC cells. The growth kinetics of NPC cells treated with silvestrol or episilvestrol were monitored dynamically using a real-time, impedance-based cell analyzer, and dose-response profiles were generated using a colorimetric cell viability assay. Furthermore, apoptosis was evaluated using flow cytometry and high content analysis. In addition, flow cytometry was performed to determine cell cycle distribution. Finally, the effects of combining silvestrol or episilvestrol with cisplatin on NPC cells was examined. Apoptosis was not observed in silvestrol and episilvestrol-treated NPC cells, although cell cycle perturbation was evident. Treatment with both compounds induced a significant increase in the percentage of cells in the G2/M phase, as compared with the control. In vitro cultures combining silvestrol or episilvestrol with cisplatin showed synergistic effects against NPC cells. The results of the present study suggested that silvestrol and episilvestrol had an anti-tumour activity in NPC cells. Silvestrol and episilvestrol, particularly in combination with cisplatin, merit further investigation, so as to determine the cellular mechanisms underlying their action(s) as anti-NPC agents.
  9. Daker M, Bhuvanendran S, Ahmad M, Takada K, Khoo AS
    Mol Med Rep, 2013 Mar;7(3):731-41.
    PMID: 23292678 DOI: 10.3892/mmr.2012.1253
    Nasopharyngeal carcinoma (NPC) is a unique tumour of epithelial origin with a distinct geographical distribution, closely associated with the Epstein‑Barr virus (EBV). EBV‑encoded RNAs (EBERs) are small non‑polyadenylated RNAs that are abundantly expressed in latent EBV‑infected NPC cells. To study the role of EBERs in NPC, we established stable expression of EBERs in HK1, an EBV‑negative NPC cell line. Cells expressing EBERs consistently exhibited an increased growth rate. However, EBERs did not confer resistance towards cisplatin‑induced apoptosis or promote migration or invasion ability in the cells tested. Using microarray gene expression profiling, we identified potential candidate genes that were deregulated in NPC cells expressing EBERs. Gene Ontology analysis of the data set revealed that EBERs upregulate the cellular lipid metabolic process. Upregulation of low‑density lipoprotein receptor (LDLR) and fatty acid synthase (FASN) was observed in EBER‑expressing cells. NPC cells exhibited LDL‑dependent cell proliferation. In addition, a polyphenolic flavonoid compound, quercetin, known to inhibit FASN, was found to inhibit proliferation of NPC cells.
  10. Khasawneh AM, Kaiwartya O, Lloret J, Abuaddous HY, Abualigah L, Shinwan MA, et al.
    Sensors (Basel), 2020 Dec 18;20(24).
    PMID: 33353003 DOI: 10.3390/s20247278
    In this paper, we propose a non-localization routing protocol for underwater wireless sensor networks (UWSNs), namely, the triangle metric based multi-layered routing protocol (TM2RP). The main idea of the proposed TM2RP is to utilize supernodes along with depth information and residual energy to balance the energy consumption between sensors. Moreover, TM2RP is the first multi-layered and multi-metric pressure routing protocol that considers link quality with residual energy to improve the selection of next forwarding nodes with more reliable and energy-efficient links. The aqua-sim package based on the ns-2 simulator was used to evaluate the performance of the proposed TM2RP. The obtained results were compared to other similar methods such as depth based routing (DBR) and multi-layered routing protocol (MRP). Simulation results showed that the proposed protocol (TM2RP) obtained better outcomes in terms of energy consumption, network lifetime, packet delivery ratio, and end-to-end delay.
  11. Kalantari K, Bin Ahmad M, Shameli K, Khandanlou R
    Int J Nanomedicine, 2013;8:1817-23.
    PMID: 23696700 DOI: 10.2147/IJN.S43693
    The aim of this research was to synthesize and develop a new method for the preparation of iron oxide (Fe(3)O(4)) nanoparticles on talc layers using an environmentally friendly process. The Fe(3)O(4) magnetic nanoparticles were synthesized using the chemical co-precipitation method on the exterior surface layer of talc mineral as a solid substrate. Ferric chloride, ferrous chloride, and sodium hydroxide were used as the Fe(3)O(4) precursor and reducing agent in talc. The talc was suspended in deionized water, and then ferrous and ferric ions were added to this solution and stirred. After the absorption of ions on the exterior surface of talc layers, the ions were reduced with sodium hydroxide. The reaction was carried out under a nonoxidizing oxygen-free environment. There were not many changes in the interlamellar space limits (d-spacing = 0.94-0.93 nm); therefore, Fe(3)O(4) nanoparticles formed on the exterior surface of talc, with an average size of 1.95-2.59 nm in diameter. Nanoparticles were characterized using different methods, including powder X-ray diffraction, transmission electron microscopy, emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. These talc/Fe(3)O(4) nanocomposites may have potential applications in the chemical and biological industries.
  12. Bibi R, Saeed Y, Zeb A, Ghazal TM, Rahman T, Said RA, et al.
    Comput Intell Neurosci, 2021;2021:6262194.
    PMID: 34630550 DOI: 10.1155/2021/6262194
    Road surface defects are crucial problems for safe and smooth traffic flow. Due to climate changes, low quality of construction material, large flow of traffic, and heavy vehicles, road surface anomalies are increasing rapidly. Detection and repairing of these defects are necessary for the safety of drivers, passengers, and vehicles from mechanical faults. In this modern era, autonomous vehicles are an active research area that controls itself with the help of in-vehicle sensors without human commands, especially after the emergence of deep learning (DNN) techniques. A combination of sensors and DNN techniques can be useful for unmanned vehicles for the perception of their surroundings for the detection of tracks and obstacles for smooth traveling based on the deployment of artificial intelligence in vehicles. One of the biggest challenges for autonomous vehicles is to avoid the critical road defects that may lead to dangerous situations. To solve the accident issues and share emergency information, the Intelligent Transportation System (ITS) introduced the concept of vehicular network termed as vehicular ad hoc network (VANET) for achieving security and safety in a traffic flow. A novel mechanism is proposed for the automatic detection of road anomalies by autonomous vehicles and providing road information to upcoming vehicles based on Edge AI and VANET. Road images captured via camera and deployment of the trained model for road anomaly detection in a vehicle could help to reduce the accident rate and risk of hazards on poor road conditions. The techniques Residual Convolutional Neural Network (ResNet-18) and Visual Geometry Group (VGG-11) are applied for the automatic detection and classification of the road with anomalies such as a pothole, bump, crack, and plain roads without anomalies using the dataset from different online sources. The results show that the applied models performed well than other techniques used for road anomalies identification.
  13. Butt MA, Ahmad M, Fatima A, Sultana S, Zafar M, Yaseen G, et al.
    J Ethnopharmacol, 2015 Jun 20;168:164-81.
    PMID: 25818693 DOI: 10.1016/j.jep.2015.03.045
    Medicinal plants represent one of the most accessible resources available for snake and scorpion bite among the rural communities of Northern Pakistan. This first ethno-botanical study aimed to document the indigenous knowledge and practices of using plants for snake and scorpion bite disorders in Northern Pakistan.
  14. Suhud K, Heng LY, Hasbullah SA, Ahmad M, Kassim MB
    Acta Crystallogr E Crystallogr Commun, 2015 Apr 1;71(Pt 4):o225-6.
    PMID: 26029426 DOI: 10.1107/S2056989015003813
    In the title compound, C13H16N2O2S, the pyrrolidine ring has a twisted conformation on the central -CH2-CH2- bond. Its mean plane is inclined to the 4-meth-oxy-benzoyl ring by 72.79 (15)°. In the crystal, mol-ecules are linked by N-H⋯O and C-H⋯O hydrogen bonds to the same O-atom acceptor, forming chains along [001]. The chains are linked via slipped parallel π-π inter-actions [inter-centroid distance = 3.7578 (13) Å], forming undulating slabs parallel to (100).
  15. Suhud K, Hasbullah SA, Ahmad M, Heng LY, Kassim MB
    Acta Crystallogr E Crystallogr Commun, 2017 Oct 01;73(Pt 10):1530-1533.
    PMID: 29250374 DOI: 10.1107/S2056989017013317
    In the title compound, C14H18N2O2S, the piperidine ring has a chair conformation. Its mean plane is twisted with respect to the 4-meth-oxy-benzoyl ring, with a dihedral angle of 63.0 (3)°. The central N-C(=S)-N(H)-C(=O) bridge is twisted with an N-C-N-C torsion angle of 74.8 (6)°. In the crystal, mol-ecules are linked by N-H⋯O and C-H⋯O hydrogen bonds, forming chains along the c-axis direction. Adjacent chains are linked by C-H⋯π inter-actions, forming layers parallel to the ac plane. The layers are linked by offset π-π inter-actions [inter-centroid distance = 3.927 (3) Å], forming a supra-molecular three-dimensional structure.
  16. Azmi NE, Ahmad M, Abdullah J, Sidek H, Heng LY, Karuppiah N
    Anal Biochem, 2009 May 1;388(1):28-32.
    PMID: 19454217 DOI: 10.1016/j.ab.2009.02.005
    An optical biosensor based on glutamate dehydrogenase (GLDH) immobilized in a chitosan film for the determination of ammonium in water samples is described. The biosensor film was deposited on a glass slide via a spin-coating method. The ammonium was measured based on beta-nicotinamide adenine dinucleotide (NADH) oxidation in the presence of alpha-ketoglutaric acid at a wavelength of 340 nm. The biosensor showed optimum activity at pH 8. The optimum chitosan concentrations and enzyme loading were found to be at 2% (w/v) and 0.08 mg, respectively. Optimum concentrations of NADH and alpha-ketoglutaric acid both were obtained at 0.15 mM. A linear response of the biosensor was obtained in the ammonium concentration range of 0.005 to 0.5 mM with a detection limit of 0.005 mM. The reproducibility of the biosensor was good, with an observed relative standard deviation of 5.9% (n=8). The biosensor was found to be stable for at least 1 month when stored dry at 4 degrees C.
  17. Tarib NA, Seong TW, Chuen KM, Kun MS, Ahmad M, Kamarudin KH
    Eur J Prosthodont Restor Dent, 2012 Mar;20(1):35-9.
    PMID: 22474935
    This paper aims to evaluate the effect of splinting during implant impression. A master model with two fixtures at the sites of 45 and 47 was used. 20 impressions were made for all four techniques: (A) indirect; (B) direct, unsplinted; (C) direct, splinted; and (D) direct, splinted, sectioned, and re-splinted. Splinting was undertaken with autopolymerizing acrylic resin (AAR). Horizontal distance between fixtures was compared using a digital caliper. The difference in distance were analysed with one-way ANOVA. Group A showed a significantly lowest accuracy among all techniques (p < or = 0.05). There was no significant difference of accuracy among the groups using direct techniques (p > or = 0.05). Group D was more accurate compared to group B and C. We conclude that splinting of impression copings would be beneficial to obtain an accurate impression.
  18. Ahmad M, Roy RA, Kamarudin AG
    Int Endod J, 1994 Jan;27(1):26-31.
    PMID: 7806408
    The present study was undertaken to see if there was any variability in the power output of Piezon-Master 400 ultrasonic files when driven using different generators, tranducers and file holders. The displacement amplitude of the oscillating tip of the file in air was used as a measure of the power output. The results showed that there was considerable variability in the power output of Piezon-Master 400 ultrasonic files of similar size and length when driven using different generators, transducers and file holders. In consideration of this, it is recommended that a calibration device be incorporated in the ultrasonic unit so that the operator will have some knowledge of when the unit is working at its maximum efficiency.
  19. Ahmad M, Roy RA, Kamarudin AG
    Endod Dent Traumatol, 1992 Oct;8(5):189-94.
    PMID: 1302678
    The steady acoustic streaming generated around straight and precurved oscillating ultrasonic files driven by the Piezon-Master 400 unit was examined in the free field and in small channels using a stereomicroscope. In addition, the effect of file-wall contact on streaming production was also investigated. The results indicated that the ultrasonic files can generate acoustic streaming both in the free field and in the small channel. Higher velocity streaming was observed when smaller size files were employed and when the file was precurved. Light file-wall contact did not totally inhibit streaming while severe file-wall contact inhibited movement of the file and, as a result, no streaming was observed. The positions and length scales of the streaming vortices appeared to be influenced by the presence of boundaries. In the free field, two rows of vortices were situated along the sides of the file while in the small channel, the vortices were positioned above the surface of the file. These results indicated that it is possible for acoustic streaming to occur in a confined space as in a root canal provided that severe file-wall contact is avoided. It is therefore recommended that light filing or allowing the file to freely vibrate during some stage of treatment should be carried out in order to generate streaming in the root canal.
  20. Khandanlou R, Bin Ahmad M, Shameli K, Kalantari K
    Molecules, 2013 Jun 05;18(6):6597-607.
    PMID: 23739066 DOI: 10.3390/molecules18066597
    Small sized magnetite iron oxide nanoparticles (Fe3O4-NPs) with were successfully synthesized on the surface of rice straw using the quick precipitation method in the absence of any heat treatment. Ferric chloride (FeCl3·6H2O), ferrous chloride (FeCl2·4H2O), sodium hydroxide (NaOH) and urea (CH4N2O) were used as Fe3O4-NPs precursors, reducing agent and stabilizer, respectively. The rice straw fibers were dispersed in deionized water, and then urea was added to the suspension, after that ferric and ferrous chloride were added to this mixture and stirred. After the absorption of iron ions on the surface layer of the fibers, the ions were reduced with NaOH by a quick precipitation method. The reaction was carried out under N2 gas. The mean diameter and standard deviation of metal oxide NPs synthesized in rice straw/Fe3O4 nanocomposites (NCs) were 9.93 ± 2.42 nm. The prepared rice straw/Fe3O4-NCS were characterized using powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDXF) and Fourier transforms infrared spectroscopy (FT‒IR). The rice straw/Fe3O4-NCs prepared by this method have magnetic properties.
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