Displaying publications 21 - 40 of 69 in total

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  1. Mohamed SIA, Jantan I, Nafiah MA, Seyed MA, Chan KM
    BMC Complement Altern Med, 2018 Aug 06;18(1):232.
    PMID: 30081891 DOI: 10.1186/s12906-018-2296-4
    BACKGROUND: Dendritic cells (DCs) are unique antigen presenting cells (APC) which play a pivotal role in immunotherapy and induction of an effective immune response against tumors. In the present study, 80% ethanol extract of Phyllanthus amarus was used to generate tumor lysate (TLY) derived from HCT 116 and MCF-7 cancer cell lines via induction of apoptosis. Monocyte-derived DCs were generated ex vivo from the adherent population of peripheral blood mononuclear cells (PBMCs). The generated TLY were used to impulse DCs to investigate its effect on their cellular immune functions including antigen presentation capacity, phagocytic activity, chemotaxis capacity, T-cell proliferation and cytokines release.

    METHODS: The effect of P. amarus-generated TLY on DCs maturation was evaluated by determination of MHC class I, II and CD 11c expression as well as the co-stimulatory molecules CD 83 and 86 by using flow cytometry. The phagocytic capacity of TLY-pulsed DCs was investigated through FITC-dextran uptake by using flow cytometry. The effect on the cytokines release including IL-12, IL-6 and IL-10 was elucidated by using ELISA. The migration capacity and T cell proliferation activity of pulsed DCs were measured. The relative gene expression levels of cytokines were determined by using qRT-PCR. The major constituents of P. amarus extract were qualitatively and quantitatively analyzed by using validated reversed-phase high performance liquid chromatography (HPLC) methods.

    RESULTS: P. amarus-generated TLY significantly up-regulated the expression levels of MHC class I, CD 11 c, CD 83 and 86 in pulsed DCs. The release of interleukin IL-12 and IL-6 was enhanced by TLY-DCs at a ratio of 1 DC: 3 tumor apoptotic bodies (APO), however, the release of IL-10 was suppressed. The migration ability as well as allogeneic T-cell proliferation activities of loaded DCs were significantly enhanced, but their phagocytic capacity was highly attenuated. The gene expression profiles for IL-12 and IL-6 of DCs showed increase in their mRNA gene expression in TLY pulsed DCs versus unloaded and LPS-treated only DCs.

    CONCLUSION: The effect of P. amarus-generated TLY on the immune effector mechanisms of DCs verified its potential to induce an in vitro anti-tumor immune response against the recognized tumor antigen.

  2. Siew EL, Farris AF, Rashid N, Chan KM, Rajab NF
    Genes Environ, 2020;42:22.
    PMID: 32537035 DOI: 10.1186/s41021-020-00161-3
    Background: Rare earth minerals of the lanthanide series are widely used in the field of medical and clinical application. Gadolinium (Gd), the most preferred rare earth mineral is frequently used as magnets, superconductors and magnetic resonance imaging (MRI) contrast agent. Increasing production of gadolinium waste, known potent toxicity of this element and lack of information on its Material Safety Data Sheet (MSDS) prompts health risk assessment on gadolinium. In this study, cytotoxicity and genotoxicity of Gadolinium (III) chloride (GdCl3) were investigated using MTT assay, Alkaline Comet assay and Micronucleus assay, respectively.

    Results: Our results demonstrated that the viability of GdCl3 treated V79-4 cells was significantly (p  0.05) DNA damage both in the presence and absence of metabolic activation. However, it induced significant (p 

  3. Nordin FJ, Pearanpan L, Chan KM, Kumolosasi E, Yong YK, Shaari K, et al.
    PLoS One, 2021;16(8):e0256012.
    PMID: 34379689 DOI: 10.1371/journal.pone.0256012
    Triple-negative breast cancer is the main type of breast carcinoma that causes mortality among women because of the limited treatment options and high recurrence. Chronic inflammation has been linked with the tumor microenvironment (TME) in breast cancer progression. Clinacanthus nutans (CN) has gained much attention because of its anticancer properties, but its mechanism remains unclear. We aimed to study the qualitative phytochemical content and elucidate the cytotoxicity effects of CN on human triple-negative breast cancer (TNBC), MDA-MB-231 and human macrophage-like cells such as THP-1 by using sulforhodamine B (SRB) assay. As highly metastatic cells, MDA-MB-231 cells can migrate to the distal position, the effect of CN on migration were also elucidated using the scratch assay. The CN effects on ameliorating chronic inflammation in TME were studied following the co-culture of MDA-MB-231/THP-1 macrophages. The cytokine expression levels of IL-6, IL-1β and tumor necrosis factor-alpha (TNF-α) were determined using ELISA assays. The results showed that both ethanolic and aqueous CN extracts contained alkaloid, phenol and tannin, flavonoid, terpenoid, glycoside and steroid. However, saponin was only found in the aqueous extract of CN. CN was not cytotoxic to both MDA-MB-231 and THP-1 cells. The ability of MDA-MB-231 to migrate was also not halted by CN treatment. However, CN ethanol extract decreased IL-6 at 25 μg/mL (p = 0.02) and 100 μg/mL (p = 0.03) but CN aqueous extract increased IL-6 expression at 50 μg/mL (p = 0.08) and 100 μg/mL (p = 0.02). IL-1β showed decreased expression after treated with CN ethanol and CN aqueous both at 25 μg/mL (p = 0.03). TNF-α were significantly decreased after CN ethanol treatment at concentration 25- (p = 0.001), 50- (p = 0.000) and 100 μg/mL (p = 0.000). CN aqueous extract slightly inhibited TNF-α at all 25-50- and 100 μg/mL (p = 0.001, p = 0.000, p = 0.000, respectively). Overall, CN acts by ameliorating the pro-inflammatory condition in the TME and may be a potential strategy for its anticancer mechanism on highly metastatic breast cancer condition. The major pathways that link both cancer and inflammation were NF-κB and STATs thus further study on the upstream and downstream pathways is needed to fully understand the mechanism of CN extracts in cooling the inflamed TME in breast cancer.
  4. Chow PW, Rajab NF, Chua KH, Chan KM, Abd Hamid Z
    Toxicol In Vitro, 2018 Feb;46:122-128.
    PMID: 28986286 DOI: 10.1016/j.tiv.2017.10.001
    Despite of reports on hematotoxic and leukemogenic evidences related to benzene exposure, the mechanism of benzene toxicity affecting the hematopoietic stem and progenitor cells (HSPCs) fate remains unclear. This study aims to elucidate the benzene's effect on the lineages-committed progenitors and genes-regulating self-renewal and differentiation of HSPCs. Isolated mouse bone marrow (BM) cells were exposed to the benzene metabolite, 1,4-benzoquinone (1,4-BQ) at 1.25, 2.5, and 5μM for 24h. The clonogenic potency of erythroid, myeloid, and Pre-B lymphoid progenitors was evaluated through colony-forming-cell assay. Quantitative real time-PCR was used to analyze the self-renewal (Bmi-1, HoxB4, and Wnt3) and differentiation (GATA1, GATA2, and GATA3)-related genes' expression levels. 1,4-BQ exposure significantly lowered the clonogenicity of the myeloid progenitor at 1.25 and 2.5μM (p<0.05), but affected neither the erythroid nor Pre-B lymphoid progenitors. Furthermore, significant upregulation of HoxB4 expression level was observed at all concentrations. GATA3 and Bmi-1 expressions were also significant upregulated at 2.5 and 5μM 1,4-BQ, respectively. In conclusion, 1,4-BQ could modulate the fate of HSPCs by altering the self-renewal and differentiation related genes. The definite role of lineages specificity and responsive genes in governing the hematotoxicity and leukemogenicity of 1,4-BQ should be further investigated.
  5. Lau CC, Aminuddin A, Chan KM, Paterson IC, Law LM, Ng PY
    Life (Basel), 2021 Nov 02;11(11).
    PMID: 34833046 DOI: 10.3390/life11111170
    Extracellular ATP in the tumor microenvironment exhibits either pro- or antitumor effect via interaction with P2Y receptors, but the intracellular signaling and functional roles of P2Y receptors in oral squamous cell carcinoma (OSCC) are unclear. We aimed to study the effect of ATP on OSCC cell lines and the potential mechanisms involved. Through GEPIA dataset analysis, high expression levels of mRNA encoding P2Y receptors, the ATP-induced G protein-coupled receptors, were associated with better overall patient survival in head and neck squamous cell carcinoma. qPCR analysis showed that the poorly differentiated OSCC SAS cell line, had higher P2RY1 expression level compared to the well-differentiated H103 and H376 cell lines. Western blotting and flow cytometry analyses revealed that ATP phosphorylated ERK and elevated intracellular calcium signaling in all tested cell lines. A significant S-phase cell cycle arrest was observed in SAS, and preincubation with the MEK inhibitor PD0325901 reversed the ATP-induced S-phase arrest. We further demonstrated that ATP induced a slight reduction in cell count and colony formation yet significant apoptosis in SAS. Overall, we postulate that the ATP-induced S-phase arrest effect in SAS cells may be regulated through P2Y receptor-mediated ERK signaling, thus suggesting a potential antitumor effect of ATP via interaction with its distinct profile of P2Y receptors.
  6. Abd Aziz NA, Awang N, Chan KM, Kamaludin NF, Mohamad Anuar NN
    Molecules, 2023 Aug 03;28(15).
    PMID: 37570810 DOI: 10.3390/molecules28155841
    Organotin (IV) dithiocarbamate has recently received attention as a therapeutic agent among organotin (IV) compounds. The individual properties of the organotin (IV) and dithiocarbamate moieties in the hybrid complex form a synergy of action that stimulates increased biological activity. Organotin (IV) components have been shown to play a crucial role in cytotoxicity. The biological effects of organotin compounds are believed to be influenced by the number of Sn-C bonds and the number and nature of alkyl or aryl substituents within the organotin structure. Ligands target and react with molecules while preventing unwanted changes in the biomolecules. Organotin (IV) dithiocarbamate compounds have also been shown to have a broad range of cellular, biochemical, and molecular effects, with their toxicity largely determined by their structure. Continuing the investigation of the cytotoxicity of organotin (IV) dithiocarbamates, this mini-review delves into the appropriate method for synthesis and discusses the elemental and spectroscopic analyses and potential cytotoxic effects of these compounds from articles published since 2010.
  7. Kamaludin NF, Kamarulzaman F, Abdullah R, Chan KM, Inayat-Hussain SH
    Genes Environ, 2023 Dec 11;45(1):34.
    PMID: 38072940 DOI: 10.1186/s41021-023-00290-5
    The Malaysian Society of Toxicology (MySOT), founded in 2010, emerged as a response to the growing need for a collective and interdisciplinary effort to study the effects of substances on human health, and the environment. By fostering collaboration between toxicologists, researchers, regulators, industry experts, and various relevant subject matter experts, MySOT has played a vital role in generating knowledge and promoting safety to safeguard both human and environmental well-being. Within the 13 years since its establishment, MySOT has made substantial progress in the advancement of toxicology in Malaysia. Over the years, MySOT has supported many initiatives, including organizing conferences, seminars, and workshops in which experts from various fields present their research, discuss emerging trends, and propose strategies to reduce toxic substance exposure risk. The society has also been actively involved in the broader landscape of toxicology research and policy influence in Malaysia. MySOT shoulders the responsibility of conveying accurate information and educating the public about health risks associated with toxic substances. Therefore, the society aims to collaborate with governmental organizations, professional bodies, and international toxicology organizations to share ideas, resources, and expertise. MySOT seeks to gather toxicological experts in the region and significantly contribute to a safer and healthier community, therefore supporting the United Nations Sustainable Development Goals (SDGs), by being actively involved with all of its stakeholders, both local and international.
  8. Razali NSC, Lam KW, Rajab NF, Jamal ARA, Kamaludin NF, Chan KM
    Genes Environ, 2024 Feb 01;46(1):4.
    PMID: 38303058 DOI: 10.1186/s41021-023-00297-y
    BACKGROUND: Previously, we have reported on the two curcuminoid analogues with piperidone derivatives, namely FLDP-5 and FLDP-8 have more potent anti-proliferative and anti-migration effects than curcumin. In this study, we further investigated the mode of cell death and the mechanism involved in the cell death process induced by these analogues on human glioblastoma LN-18 cells.

    RESULTS: The FLDP-5 and FLDP-8 curcuminoid analogues induced LN-18 cell death through apoptosis in a concentration-dependent manner following 24 h of treatment. These analogues induced apoptosis in LN-18 cells through significant loss of mitochondrial mass and mitochondrial membrane potential (MMP) as early as 1-hour of treatment. Interestingly, N-acetyl-l-cysteine (NAC) pretreatment did not abolish the apoptosis induced by these analogues, further confirming the cell death process is independent of ROS. However, the apoptosis induced by the analogues is caspases-dependent, whereby pan-caspase pretreatment inhibited the curcuminoid analogues-induced apoptosis. The apoptotic cell death progressed with the activation of both caspase-8 and caspase-9, which eventually led to the activation of caspase-3, as confirmed by immunoblotting. Moreover, the existing over-expression of miRNA-21 in LN-18 cells was suppressed following treatment with both analogues, which suggested the down-regulation of the miRNA-21 facilitates the cell death process.

    CONCLUSION: The FLDP-5 and FLDP-8 curcuminoid analogues downregulate the miRNA-21 expression and induce extrinsic and intrinsic apoptotic pathways in LN-18 cells.

  9. Leong LM, Chan KM, Hamid A, Latip J, Rajab NF
    PMID: 26884792 DOI: 10.1155/2016/2091085
    The use of herbal formulations has gained scientific interest, particularly in cancer treatment. In this study, the herbal formulation of interest, denoted as C168, is a mixture of eight genera of plants. This study aims to investigate the antiproliferative effect of C168 methanol extract (CME) on various cancer cells and its underlying mechanism of action on the most responsive cell line, namely, HCT 116 cells. CME exerted antiproliferative activities on HCT 116 colorectal carcinoma cells and HepG2 hepatocellular carcinoma cells but not on CCD-841-CoN normal colon epithelial cells, Jurkat E6.1 lymphoblastic leukemic cells, and V79-4 Chinese hamster lung fibroblasts. Further investigation on HCT 116 cells showed that CME induced G2/M cell-cycle arrest and apoptosis. Treatment of CME induced oxidative stress in HCT 116 cells by increasing the superoxide anion level and decreasing the intracellular glutathione. CME also increased tail moment value and H2AX phosphorylation in HCT 116 cells, suggesting DNA damage as an early signal of CME induced apoptosis. Loss of mitochondrial membrane potential in CME-treated cells also indicated the involvement of mitochondria in CME induced apoptosis. This study indicated the selectivity of CME toward colon cancer cells with the involvement of oxidative damage as its possible mechanism of action.
  10. Mustafa NM, Jumaah FN, Ludin NA, Akhtaruzzaman M, Hassan NH, Ahmad A, et al.
    Heliyon, 2024 Apr 15;10(7):e27381.
    PMID: 38560257 DOI: 10.1016/j.heliyon.2024.e27381
    Tetraalkylammonium salt (TAS) is an organic salt widely employed as a precursor, additive or electrolyte in solar cell applications, such as perovskite or dye-sensitized solar cells. Notably, Perovskite solar cells (PSCs) have garnered acclaim for their exceptional efficiency. However, PSCs have been associated with environmental and health concerns due to the presence of lead (Pb) content, the use of hazardous solvents, and the incorporation of TAS in their fabrication processes, which significantly contributes to environmental and human health toxicity. As a response, there is a growing trend towards transitioning to safer and biobased materials in PSC fabrication to address these concerns. However, the potential health hazards associated with TAS necessitate a thorough evaluation, considering the widespread use of this substance. Nevertheless, the overexploitation of TAS could potentially increase the disposal of TAS in the ecosystem, thus, posing a major health risk and severe pollution. Therefore, this review article presents a comprehensive discussion on the in vitro and in vivo toxicity assays of TAS as a potential material in solar energy applications, including cytotoxicity, genotoxicity, in vivo dermal, and systemic toxicity. In addition, this review emphasizes the toxicity of TAS compounds, particularly the linear tetraalkyl chain structures, and summarizes essential findings from past studies as a point of reference for the development of non-toxic and environmentally friendly TAS derivatives in future studies. The effects of the TAS alkyl chain length, polar head and hydrophobicity, cation and anion, and other properties are also included in this review.
  11. Tan JN, Husain K, Jubri Z, Chan KM, Ugusman A, Jantan I, et al.
    Int Immunopharmacol, 2024 May 07;134:112148.
    PMID: 38718657 DOI: 10.1016/j.intimp.2024.112148
    BACKGROUND: Vascular inflammation is the key event in early atherogenesis. Pro-inflammatory endothelial cells induce monocyte recruitment into the sub-endothelial layer of the artery. This requires endothelial expression of adhesion molecules namely intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), alongside chemokines production. Christia vespertilionis (L.f.) Bakh.f. (CV) possesses anti-inflammatory property. However, its potential anti-atherogenic effect in the context of vascular inflammation has yet to be explored.

    PURPOSE: To evaluate the anti-atherogenic mechanism of 80% ethanol extract of CV leaves on tumor necrosis factor-α (TNF-α)-activated human umbilical vein endothelial cells (HUVECs).

    METHODS: Qualitative analysis of the CV extract was carried out by using liquid chromatography with tandem mass spectrometry (LC-MS/MS). The cell viability of HUVECs treated with CV extract was determined by MTT assay. The effect of CV extract on monocyte adhesion was determined by monocyte-endothelial adhesion assay. Protein expressions of ICAM-1, VCAM-1 and nuclear factor-kappa B (NF-κB) signaling pathway were determined by western blot while production of monocyte chemoattractant protein-1 (MCP-1) was determined by ELISA.

    RESULTS: LC-MS/MS analysis showed that CV extract composed of five main compounds, including schaftoside, orientin, isovitexin, 6-caffeoyl-D-glucose, and 3,3'-di-O-methyl ellagic acid. Treatment of CV extract at a concentration range from 5 to 60 µg/mL for 24 h maintained HUVECs viability above 90 %, therefore concentrations of 20, 40 and 60 μg/mL were selected for the subsequent experiments. All concentrations of CV extract showed a significant inhibitory effect on monocyte adhesion to TNF-α-activated HUVECs (p 

  12. Abd Aziz NA, Awang N, Kamaludin NF, Anuar NNM, Hamid A, Chan KM, et al.
    Anticancer Agents Med Chem, 2024;24(12):942-953.
    PMID: 38629375 DOI: 10.2174/0118715206309421240402093335
    BACKGROUND: Organotin(IV) complexes of dithiocarbamate are vital in medicinal chemistry, exhibiting potential in targeting cancer cells due to their unique properties that enhance targeted delivery. This study aimed to synthesize and characterize organotin(IV) N-ethyl-N-benzyldithiocarbamate complexes (ONBDCs) and evaluate their cytotoxicity against A549 cells, which are commonly used as a model for human lung cancer research.

    METHODS: The two ONBDC derivatives - ONBDC 1 (dimethyltin(IV) N-ethyl-N-benzyldithiocarbamate) and ONBDC 2 (triphenyltin(IV) N-ethyl-N-benzyldithiocarbamate) - were synthesized via the reaction of tin(IV) chloride with N-ethylbenzylamine in the presence of carbon disulfide. A range of analytical techniques, including elemental analysis, IR spectroscopy, NMR spectroscopy, UV-Vis spectrometry, TGA/DTA analysis, and X-ray crystallography, was conducted to characterize these compounds comprehensively. The cytotoxic effects of ONBDCs against A549 cells were evaluated using MTT assay.

    RESULTS: Both compounds were synthesized and characterized successfully via elemental and spectroscopies analysis. MTT assay revealed that ONBDC 2 demonstrated remarkable cytotoxicity towards A549 cells, with an IC50 value of 0.52 μM. Additionally, ONBDC 2 displayed significantly higher cytotoxic activity against the A549 cell line when compared to the commercially available chemotherapeutic agent cisplatin (IC50: 32 μM).

    CONCLUSION: Thus, it was shown that ONBDC 2 could have important anticancer properties and should be further explored as a top contender for creating improved and specialized cancer treatments.

  13. Siew EL, Chan KM, Williams GT, Ross D, Inayat-Hussain SH
    Free Radic Biol Med, 2012 Oct 15;53(8):1616-24.
    PMID: 22687461 DOI: 10.1016/j.freeradbiomed.2012.05.046
    The Fau gene (Finkel-Biskis-Reilly murine sarcoma virus (FBR-MuSV)-associated ubiquitously expressed gene) was identified as a potential tumor suppressor gene using a forward genetics approach. Downregulation of Fau by overexpression of its reverse sequence has been shown to inhibit apoptosis induced by DNA-damaging agents. To address a potential role of Fau in benzene toxicity, we investigated the apoptotic effects of hydroquinone (HQ), a major benzene metabolite, in W7.2 mouse thymoma cells transfected with either a plasmid construct expressing the antisense sequence of Fau (rfau) or the empty vector (pcDNA3.1) as a control. HQ induced apoptosis via increased production of reactive oxygen species and DNA damage, measured using dihydroethidine (HE) staining and alkaline Comet assay, respectively, in W7.2 pcDNA3.1 cells. In contrast, when Fau was downregulated by the antisense sequence in W7.2 rfau cells, HQ treatment did not cause DNA damage and oxidative stress and these cells were markedly more resistant to HQ-induced apoptosis. Further investigation revealed that there was an upregulation of NAD(P)H: quinone oxidoreductase 1 (NQO1), a detoxification enzyme for benzene-derived quinones, in W7.2 rfau cells. Compromising cellular NQO1 by use of a specific mechanism-based inhibitor (MAC 220) and NQO1 siRNA resensitized W7.2 rfau cells to HQ-induced apoptosis. Silencing of Fau in W7.2 wild-type cells resulted in increased levels of NQO1, confirming that downregulation of Fau results in NQO1 upregulation which protects against HQ-induced apoptosis.
  14. Razali NSC, Lam KW, Rajab NF, A Jamal AR, Kamaluddin NF, Chan KM
    Sci Rep, 2022 Jul 30;12(1):13131.
    PMID: 35907913 DOI: 10.1038/s41598-022-16274-4
    Curcumin has demonstrated potential cytotoxicity across various cell lines despite its poor bioavailability and rapid metabolism. Therefore, our group have synthesized curcuminoid analogues with piperidone derivatives, FLDP-5 and FLDP-8 to overcome these limitations. In this study, the analogues were assessed on LN-18 human glioblastoma cells in comparison to curcumin. Results from cytotoxicity assessment showed that FLDP-5 and FLDP-8 curcuminoid analogues caused death in LN-18 cells in a concentration-dependent manner after 24-h treatment with much lower IC50 values of 2.5 µM and 4 µM respectively, which were more potent compared to curcumin with IC50 of 31 µM. Moreover, a significant increase (p 
  15. Inayat-Hussain SH, Chan KM, Rajab NF, Din LB, Chow SC, Kizilors A, et al.
    Toxicol Lett, 2010 Mar 1;193(1):108-14.
    PMID: 20026395 DOI: 10.1016/j.toxlet.2009.12.010
    Goniothalamin (GTN) isolated from Goniothalamus sp. has been demonstrated to induce apoptosis in a variety of cancer cell lines including Jurkat T leukemia cells. However, the mechanism of GTN-induced apoptosis upstream of mitochondria is still poorly defined. In this study, GTN caused a decrease in GSH with an elevation of reactive oxygen species as early as 30 min and DNA damage as assessed by Comet assay. Analysis using topoisomerase II processing of supercoiled pBR 322 DNA showed that GTN caused DNA damage via a topoisomerase II-independent pathway suggesting that cellular oxidative stress may contribute to genotoxicity. A 12-fold increase of caspase-2 activity was observed in GTN-treated Jurkat cells after 4h treatment and this was confirmed using Western blotting. Although the caspase-2 inhibitor Z-VDVAD-FMK inhibited the proteolytic activity of caspase-2, apoptosis ensued confirming that caspase-2 activity was not crucial for GTN-induced apoptosis. However, GTN-induced apoptosis was completely abrogated by N-acetylcysteine further confirming the role of oxidative stress. Since cytochrome c release was observed as early as 1h without any appreciable change in Bcl-2 protein expression, we further investigated whether overexpression of Bcl-2 confers resistance in GTN-induced cytotoxicity. Using a panel of Jurkat Bcl-2 transfectants, GTN cytotoxicity was not abrogated in these cells. In conclusion, GTN induces DNA damage and oxidative stress resulting in apoptosis which is independent of both caspase-2 and Bcl-2.
  16. Chan KM, Hamzah R, Rahaman AA, Jong VY, Khong HY, Rajab NF, et al.
    Food Chem Toxicol, 2012 Aug;50(8):2916-22.
    PMID: 22613213 DOI: 10.1016/j.fct.2012.04.048
    Inophyllin A (INO-A), a pyranoxanthone isolated from the roots of Calophyllum inophyllum represents a new xanthone with potential chemotherapeutic activity. In this study, the molecular mechanism of INO-A-induced cell death was investigated in Jurkat T lymphoblastic leukemia cells. Assessment of phosphatidylserine exposure confirmed apoptosis as the primary mode of cell death in INO-A-treated Jurkat cells. INO-A treatment for only 30 min resulted in a significant increase of tail moment which suggests that DNA damage is an early apoptotic signal. Further flow cytometric assessment of the superoxide anion level confirmed that INO-A induced DNA damage was mediated with a concomitant generation of reactive oxygen species (ROS). Investigation on the thiols revealed an early decrease of free thiols in 30 min after 50 μM INO-A treatment. Using tetramethylrhodamine ethyl ester, a potentiometric dye, the loss of mitochondrial membrane potential (MPP) was observed in INO-A-treated cells as early as 30 min. The INO-A-induced apoptosis progressed with the simultaneous activation of caspases-2 and -9 which then led to the processing of caspase-3. Taken together, these data demonstrate that INO-A induced early oxidative stress, DNA damage and loss of MMP which subsequently led to the activation of an intrinsic pathway of apoptosis in Jurkat cells.
  17. Ooi TC, Ibrahim FW, Ahmad S, Chan KM, Leong LM, Mohammad N, et al.
    Molecules, 2021 May 29;26(11).
    PMID: 34072474 DOI: 10.3390/molecules26113287
    Ficus deltoidea var. deltoidea is used as traditional medicine for diabetes, inflammation, and nociception. However, the antimutagenic potential and cytoprotective effects of this plant remain unknown. In this study, the mutagenic and antimutagenic activities of F. deltoidea aqueous extract (FDD) on both Salmonella typhimurium TA 98 and TA 100 strains were assessed using Salmonella mutagenicity assay (Ames test). Then, the cytoprotective potential of FDD on menadione-induced oxidative stress was determined in a V79 mouse lung fibroblast cell line. The ferric-reducing antioxidant power (FRAP) assay was conducted to evaluate FDD antioxidant capacity. Results showed that FDD (up to 50 mg/mL) did not exhibit a mutagenic effect on either TA 98 or TA 100 strains. Notably, FDD decreased the revertant colony count induced by 2-aminoanthracene in both strains in the presence of metabolic activation (p < 0.05). Additionally, pretreatment of FDD (50 and 100 µg/mL) demonstrated remarkable protection against menadione-induced oxidative stress in V79 cells significantly by decreasing superoxide anion level (p < 0.05). FDD at all concentrations tested (12.5-100 µg/mL) exhibited antioxidant power, suggesting the cytoprotective effect of FDD could be partly attributed to its antioxidant properties. This report highlights that F. deltoidea may provide a chemopreventive effect on mutagenic and oxidative stress inducers.
  18. Sulong NA, Latif MT, Khan MF, Amil N, Ashfold MJ, Wahab MIA, et al.
    Sci Total Environ, 2017 Dec 01;601-602:556-570.
    PMID: 28575833 DOI: 10.1016/j.scitotenv.2017.05.153
    This study aims to determine PM2.5concentrations and their composition during haze and non-haze episodes in Kuala Lumpur. In order to investigate the origin of the measured air masses, the Numerical Atmospheric-dispersion Modelling Environment (NAME) and Global Fire Assimilation System (GFAS) were applied. Source apportionment of PM2.5was determined using Positive Matrix Factorization (PMF). The carcinogenic and non-carcinogenic health risks were estimated using the United State Environmental Protection Agency (USEPA) method. PM2.5samples were collected from the centre of the city using a high-volume air sampler (HVS). The results showed that the mean PM2.5concentrations collected during pre-haze, haze and post-haze periods were 24.5±12.0μgm-3, 72.3±38.0μgm-3and 14.3±3.58μgm-3, respectively. The highest concentration of PM2.5during haze episode was five times higher than World Health Organisation (WHO) guidelines. Inorganic compositions of PM2.5, including trace elements and water soluble ions were determined using inductively coupled plasma-mass spectrometry (ICP-MS) and ion chromatography (IC), respectively. The major trace elements identified were K, Al, Ca, Mg and Fe which accounted for approximately 93%, 91% and 92% of the overall metals' portions recorded during pre-haze, haze and post-haze periods, respectively. For water-soluble ions, secondary inorganic aerosols (SO42-, NO3-and NH4+) contributed around 12%, 43% and 16% of the overall PM2.5mass during pre-haze, haze and post-haze periods, respectively. During haze periods, the predominant source identified using PMF was secondary inorganic aerosol (SIA) and biomass burning where the NAME simulations indicate the importance of fires in Sumatra, Indonesia. The main source during pre-haze and post-haze were mix SIA and road dust as well as mineral dust, respectively. The highest non-carcinogenic health risk during haze episode was estimated among the infant group (HI=1.06) while the highest carcinogenic health risk was estimated among the adult group (2.27×10-5).
  19. Ng CT, Fong LY, Tan JJ, Rajab NF, Abas F, Shaari K, et al.
    BMC Complement Altern Med, 2018 Jul 06;18(1):210.
    PMID: 29980198 DOI: 10.1186/s12906-018-2270-1
    BACKGROUND: Clinacanthus nutans (Burm. f.) Lindau. has traditionally been using in South East Asia countries to manage cancer. However, scientific evidence is generally lacking to support this traditional claim. This study aims to investigate the in vitro, ex-vivo and in vivo effects of C. nutans extracts on angiogenesis.

    METHODS: C. nutans leaves was extracted with 50-100% ethanol or deionised water at 1% (w/v). Human umbilical veins endothelial cell (HUVEC) proliferation was examined using MTT assay. The in vitro anti-angiogenic effects of C. nutans were assessed using wound scratch, tube formation and transwell migration assays. The VEGF levels secreted by human oral squamous cell carcinoma (HSC-4) cell and HUVEC permeability were also measured. Besides, the rat aortic ring and chick embryo chorioallantoic membrane (CAM) assays, representing ex vivo and in vivo models, respectively, were performed.

    RESULTS: The MTT assay revealed that water extract of C. nutans leaves exhibited the highest activity, compared to the ethanol extracts. Therefore, the water extract was chosen for subsequent experiments. C. nutans leaf extract significantly suppressed endothelial cell proliferation and migration in both absence and presence of VEGF. However, the water extract failed to suppress HUVEC transmigration, differentiation and permeability. C. nutans water extract also did not suppress HSC-4 cell-induced VEGF production. Importantly, C. nutans water extract significantly abolished the sprouting of vessels in aortic rings as well as in chick embryo CAM.

    CONCLUSION: In conclusion, these findings reveal potential anti-angiogenic effects of C. nutans, providing new evidence for its potential application as an anti-angiogenic agent.

  20. Ooi TC, Nordin FJ, Rahmat NS, Abdul Halim SN', Sarip R, Chan KM, et al.
    PMID: 36868695 DOI: 10.1016/j.mrgentox.2022.503581
    Complexes of coinage metals can potentially be used as alternatives to platinum-based chemotherapeutic drugs. Silver is a coinage metal that can potentially improve the spectrum of efficacy in various cancers treatment, such as malignant melanoma. Melanoma is the most aggressive form of skin cancer that is often diagnosed in young and middle-aged adults. Silver has high reactivity with skin proteins and can be developed as a malignant melanoma treatment modality. Therefore, this study aims to identify the anti-proliferative and genotoxic effects of silver(I) complexes with mixed-ligands of thiosemicarbazones and diphenyl(p-tolyl)phosphine ligands in the human melanoma SK-MEL-28 cell line. The anti-proliferative effects of a series of silver(I) complex compounds labelled as OHBT, DOHBT, BrOHBT, OHMBT, and BrOHMBT were evaluated on SK-MEL-28 cells by using the Sulforhodamine B assay. Then, DNA damage analysis was performed in a time-dependent manner (30 min, 1 h and 4 h) by using alkaline comet assay to investigate the genotoxicity of OHBT and BrOHMBT at their respective IC50 values. The mode of cell death was studied using Annexin V-FITC/PI flow cytometry assay. Our current findings demonstrated that all silver(I) complex compounds showed good anti-proliferative activity. The IC50 values of OHBT, DOHBT, BrOHBT, OHMBT, and BrOHMBT were 2.38 ± 0.3 μM, 2.70 ± 0.17 μM, 1.34 ± 0.22 μM, 2.82 ± 0.45 μM, and 0.64 ± 0.04 μM respectively. Then, DNA damage analysis showed that OHBT and BrOHMBT could induce DNA strand breaks in a time-dependent manner, with OHBT being more prominent than BrOHMBT. This effect was accompanied by apoptosis induction in SK-MEL-28, as evaluated using Annexin V-FITC/PI assay. In conclusion, silver(I) complexes with mixed-ligands of thiosemicarbazones and diphenyl(p-tolyl)phosphine exerted anti-proliferative activities by inhibiting cancer cell growth, inducing significant DNA damage and ultimately resulting in apoptosis.
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