Displaying publications 1 - 20 of 32 in total

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  1. Karen Leong SW, Wu LL
    Med J Malaysia, 2019 02;74(1):92-93.
    PMID: 30846672
    Testicular adrenal rest tumours (TART) are aberrant adrenal tissue within the testes (1). Although benign, they can lead to obstruction of the seminiferous tubules and infertility in patients with congenital adrenal hyperplasia (CAH). We report six boys who developed TART, a complication of CAH. Diagnosis was confirmed by ultrasound and testicular vein sampling of elevated 17-hydroxyprogesterone (17-OHP) levels. Glucocorticoids dosages were increased 1½-2 folds to suppress size of the aberrant adrenal tissues. Despite reductions in 17-OHP, the lesions remained unchanged. Three patients had testis-sparing surgery to excise the TART and to preserve normal testicular tissues.
  2. Ong HM, Azmi AFA, Leong SW, Abas F, Perimal EK, Farouk AAO, et al.
    Sci Rep, 2021 12 16;11(1):24121.
    PMID: 34916536 DOI: 10.1038/s41598-021-02961-1
    A novel synthetic compound from the 2-benzoyl-6-benzylidenecyclohexanone analogue, namely 2-benzoyl-6-(3-bromo-4-hydroxybenzylidene)cyclohexen-1-ol (BBHC), showed pronounced nitric oxide inhibition in IFN-γ/LPS-induced RAW 264.7 cells. Based on this previous finding, our present study aimed to investigate the antinociceptive effects of BBHC via chemical and thermal stimuli in vivo. The investigation of the antinociceptive activity of BBHC (0.1, 0.3, 1.0 and 3.0 mg/kg, i.p.) was initiated with 3 preliminary screening tests, then BBHC was subjected to investigate its possible involvement with excitatory neurotransmitters and opioid receptors. The potential acute toxicity of BBHC administration was also studied. Administration of BBHC significantly inhibited acetic acid-induced abdominal constrictions, formalin-induced paw licking activity and developed notable increment in the latency time. BBHC's ability to suppress capsaicin- and glutamate-induced paw licking activities, as well as to antagonise the effect of naloxone, had indicated the possible involvement of its antinociception with TRPV1, glutamate and opioid receptors, respectively. The antinociceptive activities of BBHC was not related to any sedative action and no evidence of acute toxic effect was detected. The present study showed that BBHC possessed significant peripheral and central antinociceptive activities via chemical- and thermal-induced nociceptive murine models without any locomotor alteration and acute toxicity.
  3. Song DSS, Leong SW, Ng KW, Abas F, Shaari K, Leong CO, et al.
    SLAS Discov, 2019 06;24(5):548-562.
    PMID: 30897027 DOI: 10.1177/2472555219831405
    DNA mismatch repair (MMR) deficiency has been associated with a higher risk of developing colorectal, endometrial, and ovarian cancer, and confers resistance in conventional chemotherapy. In addition to the lack of treatment options that work efficaciously on these MMR-deficient cancer patients, there is a great need to discover new drug leads for this purpose. In this study, we screened through a library of commercial and semisynthetic natural compounds to identify potential synthetic lethal drugs that may selectively target MLH1 mutants using MLH1 isogenic colorectal cancer cell lines and various cancer cell lines with known MLH1 status. We identified a novel diarylpentanoid analogue, 2-benzoyl-6-(2,3-dimethoxybenzylidene)-cyclohexenol, coded as AS13, that demonstrated selective toxicity toward MLH1-deficient cancer cells. Subsequent analysis suggested AS13 induced elevated levels of oxidative stress, resulting in DNA damage where only the proficient MLH1 cells were able to be repaired and hence escaping cellular death. While AS13 is modest in potency and selectivity, this discovery has the potential to lead to further drug development that may offer better treatment options for cancer patients with MLH1 deficiency.
  4. Leong SW, Faudzi SM, Abas F, Aluwi MF, Rullah K, Wai LK, et al.
    Molecules, 2014 Oct 09;19(10):16058-81.
    PMID: 25302700 DOI: 10.3390/molecules191016058
    A series of ninety-seven diarylpentanoid derivatives were synthesized and evaluated for their anti-inflammatory activity through NO suppression assay using interferone gamma (IFN-γ)/lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Twelve compounds (9, 25, 28, 43, 63, 64, 81, 83, 84, 86, 88 and 97) exhibited greater or similar NO inhibitory activity in comparison with curcumin (14.7 ± 0.2 µM), notably compounds 88 and 97, which demonstrated the most significant NO suppression activity with IC50 values of 4.9 ± 0.3 µM and 9.6 ± 0.5 µM, respectively. A structure-activity relationship (SAR) study revealed that the presence of a hydroxyl group in both aromatic rings is critical for bioactivity of these molecules. With the exception of the polyphenolic derivatives, low electron density in ring-A and high electron density in ring-B are important for enhancing NO inhibition. Meanwhile, pharmacophore mapping showed that hydroxyl substituents at both meta- and para-positions of ring-B could be the marker for highly active diarylpentanoid derivatives.
  5. Hisamuddin N, Shaik Mossadeq WM, Sulaiman MR, Abas F, Leong SW, Kamarudin N, et al.
    Molecules, 2019 Jul 18;24(14).
    PMID: 31323775 DOI: 10.3390/molecules24142614
    Curcumin, derived from the rhizome Curcuma longa, has been scientifically proven to possess anti-inflammatory activity but is of limited clinical and veterinary use owing to its low bioavailability and poor solubility. Hence, analogs of curcuminoids with improved biological properties have been synthesized to overcome these limitations. This study aims to provide the pharmacological basis for the use of 5-(3,4-dihydroxyphenyl)-3-hydroxy-1-(2-hydroxyphenyl)penta-2,4-dien-1-one (DHHPD), a synthetic curcuminoid analog, as an anti-edematogenic and anti-granuloma agent. The carrageenan-induced paw edema and the cotton pellet-induced granuloma assays were used to assess the anti-inflammatory activity of DHHPD in mice. The effects of DHHPD on the histaminergic, serotonergic, and bradykininergic systems were determined by the histamine-, serotonin-, and bradykinin-induced paw edema tests, respectively. DHHPD (0.1, 0.3, 1, and 3 mg/kg, intraperitoneal) evoked significant reductions (p < 0.05) in carrageenan-induced paw edema at different time intervals and granuloma formation (p < 0.0001) by 22.08, 32.57, 37.20, and 49.25%, respectively. Furthermore, DHHPD significantly reduced paw edema (p < 0.05) induced by histamine, serotonin, and bradykinin. The present study suggests that DHHPD exerts anti-edematogenic activity, possibly by inhibiting the synthesis or release of autacoid mediators of inflammation through the histaminergic, serotonergic, and bradykininergic systems. The anti-granuloma effect may be attributed to the suppression of transudative, exudative, and proliferative activities associated with inflammation.
  6. Kamarudin N, Hisamuddin N, Ong HM, Ahmad Azmi AF, Leong SW, Abas F, et al.
    Molecules, 2018 Aug 21;23(9).
    PMID: 30134576 DOI: 10.3390/molecules23092099
    Curcuminoids derived from turmeric rhizome have been reported to exhibit antinociceptive, antioxidant and anti-inflammatory activities. We evaluated the peripheral and central antinociceptive activities of 5-(3,4-dihydroxyphenyl)-3-hydroxy-1-(2-hydroxyphenyl)penta-2,4-dien-1-one (DHHPD), a novel synthetic curcuminoid analogue at 0.1, 0.3, 1 and 3 mg/kg (intraperitoneal), through chemical and thermal models of nociception. The effects of DHHPD on the vanilloid and glutamatergic systems were evaluated through the capsaicin- and glutamate-induced paw licking tests. Results showed that DHHPD significantly (p < 0.05) attenuated the writhing response produced by the 0.8% acetic acid injection. In addition, 1 and 3 mg/kg of DHHPD significantly (p < 0.05) reduced the licking time spent by each mouse in both phases of the 2.5% formalin test and increased the response latency of mice on the hot-plate. However, the effect produced in the latter was not reversed by naloxone, a non-selective opioid receptor antagonist. Despite this, DHHPD decreased the licking latency of mice in the capsaicin- and glutamate-induced paw licking tests in a dose response manner. In conclusion, DHHPD showed excellent peripheral and central antinociceptive activities possibly by attenuation of the synthesis and/or release of pro-inflammatory mediators in addition to modulation of the vanilloid and glutamatergic systems without an apparent effect on the opioidergic system.
  7. Leong SW, Chia SL, Abas F, Yusoff K
    Molecules, 2020 Aug 26;25(17).
    PMID: 32858795 DOI: 10.3390/molecules25173877
    In the present study, we investigated the in-vitro anti-cancer potential of six diarylpentanoids against a panel of BRAF- and KRAS-mutated colorectal cancer cell lines including T84, SW620, LoVo, HT29, NCI-H508, RKO, and LS411N cells. Structure-activity relationship study suggested that the insertions of tetrahydro-4H-thiopyran-4-one and brominated phenyl moieties are essential for better cytotoxicity. Among the evaluated analogs, 2e has been identified as the lead compound due to its low IC50 values of approximately 1 µM across all cancer cell lines and high chemotherapeutic index of 7.1. Anti-proliferative studies on LoVo cells showed that 2e could inhibit cell proliferation and colony formations by inducing G2/M cell cycle arrest. Subsequent cell apoptosis assay confirmed that 2e is a Bcl-2 inhibitor that could induce intrinsic cell apoptosis by creating a cellular redox imbalance through its direct inhibition on the Bcl-2 protein. Further molecular docking studies revealed that the bromophenyl moieties of 2e could interact with the Bcl-2 surface pocket through hydrophobic interaction, while the tetrahydro-4H-thiopyran-4-one fragment could form additional Pi-sulfur and Pi-alkyl interactions in the same binding site. In all, the present results suggest that 2e could be a potent lead that deserves further modification and investigation in the development of a new Bcl-2 inhibitor.
  8. Ban A, Omar A, Chong LY, Lockman H, Ida Zaliza ZA, Ali I, et al.
    Malays Fam Physician, 2018;13(3):20-26.
    PMID: 30800229 MyJurnal
    Asthma is a chronic inflammatory disease of the airway which is often misdiagnosed and undertreated. Early diagnosis and vigilant asthma control are crucial to preventing permanent airway damage, improving quality of life and reducing healthcare burdens. The key approaches to asthma management should include patient empowerment through health education and self-management and, an effective patient-healthcare provider partnership.
  9. Flaherty GT, Leong SW, Finn Y, Sulaiman LH, Noone C
    J Travel Med, 2020 Sep 26;27(6).
    PMID: 32634210 DOI: 10.1093/jtm/taaa110
    BACKGROUND: Little is known about the awareness of travellers with diabetes about the health effects of international travel. This study aimed to design and validate a questionnaire to examine the travel health knowledge, attitudes and practices of people living with type 1 diabetes.

    METHODS: A set of 74 items based on a conceptual framework analysis underwent revision and its content validity was established. Items were grouped into three domains. A development study was conducted to establish evidence regarding their factorial structure. A construct validation study was then conducted in which the retained items were tested in an independent sample using confirmatory factor analysis (CFA).

    RESULTS: Four factors emerged from our development study and were labelled as pre-travel preparation-insect bites, pre-travel preparation-consultation, insulin and glycaemic control and travel risk behaviour. A CFA confirmed the factorial structure identified in the development study in an independent sample. Each factor loading had a significant (P 

  10. Leong SW, Lim TS, Ismail A, Choong YS
    J. Mol. Recognit., 2018 05;31(5):e2695.
    PMID: 29230887 DOI: 10.1002/jmr.2695
    With the development of de novo binders for protein targets from non-related scaffolds, many possibilities for therapeutics and diagnostics have been created. In this study, we described the use of de novo design approach to create single-chain fragment variable (scFv) for Salmonella enterica subspecies enterica serovar Typhi TolC protein. Typhoid fever is a global health concern in developing and underdeveloped countries. Rapid typhoid diagnostics will improve disease management and therapy. In this work, molecular dynamics simulation was first performed on a homology model of TolC protein in POPE membrane bilayer to obtain the central structure that was subsequently used as the target for scFv design. Potential hotspot residues capable of anchoring the binders to the target were identified by docking "disembodied" amino acid residues against TolC surface. Next, scFv scaffolds were selected from Protein Data Bank to harbor the computed hotspot residues. The hotspot residues were then incorporated into the scFv scaffold complementarity determining regions. The designs recapitulated binding energy, shape complementarity, and interface surface area of natural protein-antibody interfaces. This approach has yielded 5 designs with high binding affinity against TolC that may be beneficial for the future development of antigen-based detection agents for typhoid diagnostics.
  11. Leong SW, Lim TS, Tye GJ, Ismail A, Aziah I, Choong YS
    J Biol Phys, 2014 Sep;40(4):387-400.
    PMID: 25011632 DOI: 10.1007/s10867-014-9357-9
    In this work we assessed the suitability of two different lipid membranes for the simulation of a TolC protein from Salmonella enterica serovar Typhi. The TolC protein family is found in many pathogenic Gram-negative bacteria including Vibrio cholera and Pseudomonas aeruginosa and acts as an outer membrane channel for expulsion of drug and toxin from the cell. In S. typhi, the causative agent for typhoid fever, the TolC outer membrane protein is an antigen for the pathogen. The lipid environment is an important modulator of membrane protein structure and function. We evaluated the conformation of the TolC protein in the presence of DMPE and POPE bilayers using molecular dynamics simulation. The S. typhi TolC protein exhibited similar conformational dynamics to TolC and its homologues. Conformational flexibility of the protein is seen in the C-terminal, extracellular loops, and α-helical region. Despite differences in the two lipids, significant similarities in the motion of the protein in POPE and DMPE were observed, including the rotational motion of the C-terminal residues and the partially open extracellular loops. However, analysis of the trajectories demonstrated effects of hydrophobic matching of the TolC protein in the membrane, particularly in the lengthening of the lipids and subtle movements of the protein's β-barrel towards the lower leaflet in DMPE. The study exhibited the use of molecular dynamics simulation in revealing the differential effect of membrane proteins and lipids on each other. In this study, POPE is potentially a more suitable model for future simulation of the S. typhi TolC protein.
  12. Velaithan V, Okuda KS, Ng MF, Samat N, Leong SW, Faudzi SM, et al.
    Invest New Drugs, 2017 04;35(2):250.
    PMID: 28185040 DOI: 10.1007/s10637-017-0437-0
  13. Velaithan V, Okuda KS, Ng MF, Samat N, Leong SW, Faudzi SM, et al.
    Invest New Drugs, 2017 04;35(2):166-179.
    PMID: 28058624 DOI: 10.1007/s10637-016-0423-y
    Zebrafish represents a powerful in vivo model for phenotype-based drug discovery to identify clinically relevant small molecules. By utilizing this model, we evaluated natural product derived compounds that could potentially modulate Notch signaling that is important in both zebrafish embryogenesis and pathogenic in human cancers. A total of 234 compounds were screened using zebrafish embryos and 3 were identified to be conferring phenotypic alterations similar to embryos treated with known Notch inhibitors. Subsequent secondary screens using HEK293T cells overexpressing truncated Notch1 (HEK293TΔE) identified 2 compounds, EDD3 and 3H4MB, to be potential Notch antagonists. Both compounds reduced protein expression of NOTCH1, Notch intracellular domain (NICD) and hairy and enhancer of split-1 (HES1) in HEK293TΔE and downregulated Notch target genes. Importantly, EDD3 treatment of human oral cancer cell lines demonstrated reduction of Notch target proteins and genes. EDD3 also inhibited proliferation and induced G0/G1 cell cycle arrest of ORL-150 cells through inducing p27KIP1. Our data demonstrates the utility of the zebrafish phenotypic screen and identifying EDD3 as a promising Notch antagonist for further development as a novel therapeutic agent.
  14. Ramli AH, Swain P, Mohd Fahmi MSA, Abas F, Leong SW, Tejo BA, et al.
    Heliyon, 2024 Mar 15;10(5):e27462.
    PMID: 38495201 DOI: 10.1016/j.heliyon.2024.e27462
    Malaria remains a major public health problem worldwide, including in Southeast Asia. Chemotherapeutic agents such as chloroquine (CQ) are effective, but problems with drug resistance and toxicity have necessitated a continuous search for new effective antimalarial agents. Here we report on a virtual screening of ∼300 diarylpentanoids and derivatives, in search of potential Plasmodium falciparum lactate dehydrogenase (PfLDH) inhibitors with acceptable drug-like properties. Several molecules with binding affinities comparable to CQ were chosen for in vitro validation of antimalarial efficacy. Among them, MS33A, MS33C and MS34C are the most promising against CQ-sensitive (3D7) with EC50 values of 1.6, 2.5 and 3.1 μM, respectively. Meanwhile, MS87 (EC50 of 1.85 μM) shown the most active against the CQ-resistant Gombak A strain, and MS33A and MS33C the most effective P. knowlesi inhibitors (EC50 of 3.6 and 5.1 μM, respectively). The in vitro cytotoxicity of selected diarylpentanoids (MS33A, MS33C, MS34C and MS87) was tested on Vero mammalian cells to evaluate parasite selectivity (SI), showing moderate to low cytotoxicity (CC50 > 82 μM). In addition, MS87 exhibited a high SI and the lowest resistance index (RI), suggesting that MS87 may exert effective parasite inhibition with low resistance potential in the CQ-resistant P. falciparum strain. Furthermore, the in vivo toxicity of the molecules on early embryonic development, the cardiovascular system, heart rate, motor activity and apoptosis were assessed in a zebrafish animal model. The overall results indicate the preliminary potential of diarylpentanoids, which need further investigation for their development as new antimalarial agents.
  15. Rullah K, Shamsudin NF, Koeberle A, Tham CL, Fasihi Mohd Aluwi MF, Leong SW, et al.
    Future Med Chem, 2024 Jan;16(1):75-99.
    PMID: 38205612 DOI: 10.4155/fmc-2023-0174
    Targeting lipopolysaccharide (LPS)/toll-like receptor 4 signaling in mononuclear phagocytes has been explored for the treatment of inflammation and inflammation-related disorders. However, only a few key targets have been translated into clinical applications. Flavonoids, a class of ubiquitous plant secondary metabolites, possess a privileged scaffold which serves as a valuable template for designing pharmacologically active compounds directed against diseases with inflammatory components. This perspective provides a general overview of the diversity of flavonoids and their multifaceted mechanisms that interfere with LPS-induced signaling in monocytes and macrophages. Focus is placed on flavonoids targeting MD-2, IκB kinases, c-Jun N-terminal kinases, extracellular signal-regulated kinase, p38 MAPK and PI3K/Akt or modulating LPS-related gene expression.
  16. Leong SW, Chia SL, Abas F, Yusoff K
    Eur J Med Chem, 2018 Sep 05;157:716-728.
    PMID: 30138803 DOI: 10.1016/j.ejmech.2018.08.039
    In the present study, a series of forty-five asymmetrical meta-methoxylated diarylpentanoids have been synthesized, characterized and evaluated for their in-vitro anti-cancer potential. Among the forty-five analogs, three compounds (20, 33 and 42) have been identified as lead compounds due to their excellent inhibition against five human cancer cell lines including SW620, A549, EJ28, HT1080 and MCF-7. Structure-activity relationship study on cytotoxicity of tested compounds suggested that the presence of meta-oxygenated phenyl ring played a critical role in enhancing their cytotoxic effects. Compounds 33 and 42 in particular, exhibited strongest cytotoxicity against tested cell lines with the IC50 values ranging from 1.1 to 4.3 μM. Subsequent colony formation assay on SW620 cell line showed that both compounds 33 and 42 possessed strong anti-proliferative activity. In addition, flow cytometry based experiments revealed that these compounds could trigger intracellular ROS production thus inducing G2/M-phase cell arrest and apoptosis. All these results suggested that poly meta-oxygenated diarylpentnoid is a promising scaffold which deserved further modification and investigation in the development of natural product-based anti-cancer drug.
  17. Leong SW, Wang J, Okuda KS, Su Q, Zhang Y, Abas F, et al.
    Eur J Med Chem, 2023 Apr 20;254:115335.
    PMID: 37098306 DOI: 10.1016/j.ejmech.2023.115335
    Unpleasant side effects and resistance development remained the Achilles heel of chemotherapy. Since low tumor-selectivity and monotonous effect of chemotherapy are closely related to such bottleneck, targeting tumor-selective multi-functional anticancer agents may be an ideal strategy in the search of new safer drugs. Herein, we report the discovery of compound 21, a nitro-substituted 1,5-diphenyl-3-styryl-1H-pyrazole that possesses dual functional characteristics. The 2D- and 3D-culture-based studies revealed that 21 not only could induce ROS-independent apoptotic and EGFR/AKT/mTOR-mediated autophagic cell deaths in EJ28 cells simultaneously but also has the ability in inducing cell death at both proliferating and quiescent zones of EJ28 spheroids. The molecular modelling analysis showed that 21 possesses EGFR targeting capability as it forms stable interactions in the EGFR active site. Together with its good safety profile in the zebrafish-based model, the present study showed that 21 is promising and may lead to the discovery of tumor-selective multi-functional anti-cancer agents.
  18. Ullah A, Leong SW, Wang J, Wu Q, Ghauri MA, Sarwar A, et al.
    Cell Death Dis, 2021 05 14;12(5):490.
    PMID: 33990544 DOI: 10.1038/s41419-021-03771-z
    Lung cancer (LC) is one of the leading causes of cancer-related death. As one of the key features of tumor microenvironment, hypoxia conditions are associated with poor prognosis in LC patients. Upregulation of hypoxic-induced factor-1α (HIF-1α) leads to the activation of various factors that contribute to the increased drug resistance, proliferation, and migration of tumor cells. Apurinic/apyrimidinic endonuclease-1 (APEX1) is a multi-functional protein that regulates several transcription factors, including HIF-1α, that contribute to tumor growth, oxidative stress responses, and DNA damage. In this study, we explored the mechanisms underlying cell responses to hypoxia and modulation of APEX1, which regulate HIF-1α and downstream pathways. We found that hypoxia-induced APEX1/HIF-1α pathways regulate several key cellular functions, including reactive oxygen species (ROS) production, carbonic anhydrase 9 (CA9)-mediated intracellular pH, migration, and angiogenesis. Cephalomannine (CPM), a natural compound, exerted inhibitory effects in hypoxic LC cells via the inhibition of APEX1/HIF-1α interaction in vitro and in vivo. CPM can significantly inhibit cell viability, ROS production, intracellular pH, and migration in hypoxic LC cells as well as angiogenesis of HUVECs under hypoxia through the inhibition of APEX1/HIF-1α interaction. Taken together, CPM could be considered as a promising compound for LC treatment.
  19. Abdullah MA, Lee YR, Mastuki SN, Leong SW, Wan Ibrahim WN, Mohammad Latif MA, et al.
    Bioorg Chem, 2020 11;104:104277.
    PMID: 32971414 DOI: 10.1016/j.bioorg.2020.104277
    A series of aminated- (1-9) and sulfonamide-containing diarylpentadienones (10-18) were synthesized, structurally characterized, and evaluated for their in vitro anti-diabetic potential on α-glucosidase and DPP-4 enzymes. It was found that all the new molecules were non-associated PAINS compounds. The sulfonamide-containing series (compounds 10-18) selectively inhibited α-glucosidase over DPP-4, in which compound 18 demonstrated the highest activity with an IC50 value of 5.69 ± 0.5 µM through a competitive inhibition mechanism. Structure-activity relationship (SAR) studies concluded that the introduction of the trifluoromethylbenzene sulfonamide moiety was essential for the suppression of α-glucosidase. The most active compound 18, was then further tested for in vivo toxicities using the zebrafish animal model, with no toxic effects detected in the normal embryonic development, blood vessel formation, and apoptosis of zebrafish. Docking simulation studies were also carried out to better understand the binding interactions of compound 18 towards the homology modeled α -glucosidase and the human lysosomal α -glucosidase enzymes. The overall results suggest that the new sulfonamide-containing diarylpentadienones, compound 18, could be a promising candidate in the search for a new α-glucosidase inhibitor, and can serve as a basis for further studies involving hit-to-lead optimization, in vivo efficacy and safety assessment in an animal model and mechanism of action for the treatment of T2DM patients.
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