Displaying publications 101 - 119 of 119 in total

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  1. Fulltext [Zinc induces normoxic accumulation of transcriptionally active hypoxia-inducible factor 1-alpha in mammary epithelial cells]
    Lee SY, Mustafa S, Ching YW, Shafee N
    Mol Biol (Mosk), 2017 3 3;51(1):104-110.
    PMID: 28251972 DOI: 10.7868/S0026898417010116
    Both zinc and the α-subunit of hypoxia-inducible factor (HIF-1α) play important roles in the remodelling of mammary gland tissues. In the present study, we examined the level and the transcriptional activity of HIF-1α in mammary cells upon zinc treatment. In MCF-7 mammary adenocarcinoma and MCF-10A mammary epithelial cell lines, the toxicity levels of zinc differ. Interestingly, both cell lines overexpress HIF-1α following zinc treatment. As it was evident from an up-regulation of its specific target gene CA9 that encodes carbonic anhydrase IX, the stabilized HIF-1α translocated to the nucleus and was transcriptionally active. Hence, we conclude that zinc causes normoxic accumulation of transcriptionally active HIF-1α by interfering with its post-translational regulation.
    Matched MeSH terms: Cell Nucleus
  2. Integrative analysis of chloroplast DNA methylation in a marine alga-Saccharina japonica
    Teng L, Han W, Fan X, Zhang X, Xu D, Wang Y, et al.
    Plant Mol Biol, 2021 Apr;105(6):611-623.
    PMID: 33528753 DOI: 10.1007/s11103-020-01113-9
    We applied an integrative approach using multiple methods to verify cytosine methylation in the chloroplast DNA of the multicellular brown alga Saccharina japonica. Cytosine DNA methylation is a heritable process which plays important roles in regulating development throughout the life cycle of an organism. Although methylation of nuclear DNA has been studied extensively, little is known about the state and role of DNA methylation in chloroplast genomes, especially in marine algae. Here, we have applied an integrated approach encompassing whole-genome bisulfite sequencing, methylated DNA immunoprecipitation, gene co-expression networks and photophysiological analyses to provide evidence for the role of chloroplast DNA methylation in a marine alga, the multicellular brown alga Saccharina japonica. Although the overall methylation level was relatively low in the chloroplast genome of S. japonica, gametophytes exhibited higher methylation levels than sporophytes. Gene-specific bisulfite-cloning sequencing provided additional evidence for the methylation of key photosynthetic genes. Many of them were highly expressed in sporophytes whereas genes involved in transcription, translation and biosynthesis were strongly expressed in gametophytes. Nucleus-encoded photosynthesis genes were co-expressed with their chloroplast-encoded counterparts potentially contributing to the higher photosynthetic performance in sporophytes compared to gametophytes where these co-expression networks were less pronounced. A nucleus-encoded DNA methyltransferase of the DNMT2 family is assumed to be responsible for the methylation of the chloroplast genome because it is predicted to possess a plastid transit peptide.
    Matched MeSH terms: Cell Nucleus
  3. Fulltext Gelam honey attenuates carrageenan-induced rat paw inflammation via NF-κB pathway
    Hussein SZ, Mohd Yusoff K, Makpol S, Mohd Yusof YA
    PLoS One, 2013;8(8):e72365.
    PMID: 24015236 DOI: 10.1371/journal.pone.0072365
    The activation of nuclear factor kappa B (NF-κB) plays a major role in the pathogenesis of a number of inflammatory diseases. In this study, we investigated the anti-inflammatory mechanism of Gelam honey in inflammation induced rats via NF-κB signalling pathway. Rats paw edema was induced by subplantar injection of 1% carrageenan into the right hind paw. Rats were pre-treated with Gelam honey at different doses (1 or 2 g/kg, p.o.) and NSAID Indomethacin (10 mg/kg, p.o.), in two time points (1 and 7 days). Our results showed that Gelam honey at both concentrations suppressed the gene expressions of NF-κB (p65 & p50) and IκBα in inflamed rats paw tissues. In addition, Gelam honey inhibited the nuclear translocation and activation of NF-κB and decreased the cytosolic degradation of IκBα dose dependently in inflamed rats paw tissues. The immunohistochemical expressions of pro-inflammatory mediators COX-2 and TNF-α were also decreased in inflamed rats paw tissues when treated with Gelam honey. The results of our findings suggest that Gelam honey exhibits its inhibitory effects by attenuating NF-κB translocation to the nucleus and inhibiting IκBα degradation, with subsequent decrease of inflammatory mediators COX-2 and TNF-α.
    Matched MeSH terms: Cell Nucleus/metabolism
  4. Differential expression of transcription factors Snail, Slug, SIP1, and Twist in ameloblastoma
    Siar CH, Ng KH
    J Oral Pathol Med, 2014 Jan;43(1):45-52.
    PMID: 23560539 DOI: 10.1111/jop.12065
    Epithelial-to-mesenchymal transition (EMT) via the mechanism of transcription repression is a crucial process for the induction of invasiveness in many human tumors. Ameloblastoma is a benign odontogenic epithelial neoplasm with a locally infiltrative behavior. Twist, an EMT promoter, has been implicated in its invasiveness. The roles of the other transcription factors remain unclarified.
    Matched MeSH terms: Cell Nucleus/ultrastructure
  5. Claudin expression and tight junction protein localization in the lining epithelium of the keratocystic odontogenic tumors, dentigerous cysts, and radicular cysts
    Siar CH, Abbas SA
    Oral Surg Oral Med Oral Pathol Oral Radiol, 2013 May;115(5):652-9.
    PMID: 23601220 DOI: 10.1016/j.oooo.2013.02.013
    The aim of this study was to evaluate the expression and localization of tight junction proteins (TJPs) or claudins in the keratocystic odontogenic tumor (KCOT) and to correlate with its biological behavior.
    Matched MeSH terms: Cell Nucleus/pathology
  6. Differential expression of Notch receptors and their ligands in desmoplastic ameloblastoma
    Siar CH, Nakano K, Han PP, Nagatsuka H, Ng KH, Kawakami T
    J Oral Pathol Med, 2010 Aug 1;39(7):552-8.
    PMID: 20337864 DOI: 10.1111/j.1600-0714.2009.00871.x
    In mammals, the Notch gene family encodes four receptors (Notch1-4), and all of them are important for cell fate decisions. Notch signaling pathway plays an essential role in tooth development. The ameloblastoma, a benign odontogenic epithelial neoplasm, histologically recapitulates the enamel organ at bell stage. Notch has been detected in the plexiform and follicular ameloblastoma. Its activity in the desmoplastic ameloblastoma is unknown.
    Matched MeSH terms: Cell Nucleus/ultrastructure
  7. PNMA2 mediates heterodimeric interactions and antagonizes chemo-sensitizing activities mediated by members of PNMA family
    Lee YH, Pang SW, Tan KO
    Biochem Biophys Res Commun, 2016 Apr 22;473(1):224-229.
    PMID: 27003254 DOI: 10.1016/j.bbrc.2016.03.083
    PNMA2, a member of the Paraneoplastic Ma Family (PNMA), was identified through expression cloning by using anti-sera from patients with paraneoplastic disorder. Tissue expression studies showed that PNMA2 was predominantly expressed in normal human brain; however, the protein was shown to exhibit abnormal expression profile as it was found to be expressed in a number of tumour tissues obtained from paraneopalstic patients. The abnormal expression profile of PNMA2 suggests that it might play an important role in tumorigenesis; however, apart from protein expression and immunological studies, the physiological role of PNMA2 remains unclear. In order to determine potential role of PNMA2 in tumorigenesis, and its functional relationship with PNMA family members, MOAP-1 (PNMA4) and PNMA1, expression constructs encoding the respective proteins were generated for both in vitro and in vivo studies. Our investigations showed that over-expressed MOAP-1 and PNMA1 promoted apoptosis and chemo-sensitization in MCF-7 cells as evidenced by condensed nuclei and Annexin-V positive MCF-7 cells; however, the effects mediated by these proteins were significantly inhibited or abolished when co-expressed with PNMA2 in MCF-7 cells. Furthermore, co-immunoprecipitation study showed that PNMA1 and MOAP-1 failed to associate with each other but readily formed respective heterodimer with PNMA2, suggesting that PNMA2 functions as antagonist of MOAP-1 and PNMA1 through heterodimeric interaction.
    Matched MeSH terms: Cell Nucleus/metabolism
  8. Fulltext Resveratrol treatment reveals a novel role for HMGB1 in regulation of the type 1 interferon response in dengue virus infection
    Zainal N, Chang CP, Cheng YL, Wu YW, Anderson R, Wan SW, et al.
    Sci Rep, 2017 02 20;7:42998.
    PMID: 28216632 DOI: 10.1038/srep42998
    Dengue is one of the most significant mosquito-borne virus diseases worldwide, particularly in tropical and subtropical regions. This study sought to examine the antiviral activity of resveratrol (RESV), a phytoalexin secreted naturally by plants, against dengue virus (DENV) infection. Our data showed that RESV inhibits the translocation of high mobility group box 1 (HMGB1), a DNA binding protein that normally resides in the nucleus, into the cytoplasm and extracellular milieu. HMGB1 migrates out of the nucleus during DENV infection. This migration is inhibited by RESV treatment and is mediated by induction of Sirt1 which leads to the retention of HMGB1 in the nucleus and consequently helps in the increased production of interferon-stimulated genes (ISGs). Nuclear HMGB1 was found to bind to the promoter region of the ISG and positively regulated the expression of ISG. The enhanced transcription of ISGs by nuclear HMGB1 thus contributes to the antiviral activity of RESV against DENV. To the best of our knowledge, this is the first report to demonstrate that RESV antagonizes DENV replication and that nuclear HMGB1 plays a role in regulating ISG production.
    Matched MeSH terms: Cell Nucleus/metabolism
  9. Fulltext Antioxidant Activity and ROS-Dependent Apoptotic Effect of Scurrula ferruginea (Jack) Danser Methanol Extract in Human Breast Cancer Cell MDA-MB-231
    Marvibaigi M, Amini N, Supriyanto E, Abdul Majid FA, Kumar Jaganathan S, Jamil S, et al.
    PLoS One, 2016;11(7):e0158942.
    PMID: 27410459 DOI: 10.1371/journal.pone.0158942
    Scurrula ferruginea (Jack) Danser is one of the mistletoe species belonging to Loranthaceae family, which grows on the branches of many deciduous trees in tropical countries. This study evaluated the antioxidant activities of S. ferruginea extracts. The cytotoxic activity of the selected extracts, which showed potent antioxidant activities, and high phenolic and flavonoid contents, were investigated in human breast cancer cell line (MDA-MB-231) and non-cancer human skin fibroblast cells (HSF-1184). The activities and characteristics varied depending on the different parts of S. ferruginea, solvent polarity, and concentrations of extracts. The stem methanol extract showed the highest amount of both phenolic (273.51 ± 4.84 mg gallic acid/g extract) and flavonoid contents (163.41 ± 4.62 mg catechin/g extract) and strong DPPH• radical scavenging (IC50 = 27.81 μg/mL) and metal chelation activity (IC50 = 80.20 μg/mL). The stem aqueous extract showed the highest ABTS•+ scavenging ability. The stem methanol and aqueous extracts exhibited dose-dependent cytotoxic activity against MDA-MB-231 cells with IC50 of 19.27 and 50.35 μg/mL, respectively. Furthermore, the extracts inhibited the migration and colony formation of MDA-MB-231 cells in a concentration-dependent manner. Morphological observations revealed hallmark properties of apoptosis in treated cells. The methanol extract induced an increase in ROS generation and mitochondrial depolarization in MDA-MB-231 cells, suggesting its potent apoptotic activity. The present study demonstrated that the S. ferruginea methanol extract mediated MDA-MB-231 cell growth inhibition via induction of apoptosis which was confirmed by Western blot analysis. It may be a potential anticancer agent; however, its in vivo anticancer activity needs to be investigated.
    Matched MeSH terms: Cell Nucleus/drug effects
  10. Fulltext Aqueous fraction of Nephelium ramboutan-ake rind induces mitochondrial-mediated apoptosis in HT-29 human colorectal adenocarcinoma cells
    Chan CK, Goh BH, Kamarudin MN, Kadir HA
    Molecules, 2012 May 31;17(6):6633-57.
    PMID: 22728359 DOI: 10.3390/molecules17066633
    The aim of this study was to investigate the cytotoxic and apoptotic effects of Nephelium ramboutan-ake (pulasan) rind in selected human cancer cell lines. The crude ethanol extract and fractions (ethyl acetate and aqueous) of N. ramboutan-ake inhibited the growth of HT-29, HCT-116, MDA-MB-231, Ca Ski cells according to MTT assays. The N. ramboutan-ake aqueous fraction (NRAF) was found to exert the greatest cytotoxic effect against HT-29 in a dose-dependent manner. Evidence of apoptotic cell death was revealed by features such as chromatin condensation, nuclear fragmentation and apoptotic body formation. The result from a TUNEL assay strongly suggested that NRAF brings about DNA fragmentation in HT-29 cells. Phosphatidylserine (PS) externalization on the outer leaflet of plasma membranes was detected with annexin V-FITC/PI binding, confirming the early stage of apoptosis. The mitochondrial permeability transition is an important step in the induction of cellular apoptosis, and the results clearly suggested that NRAF led to collapse of mitochondrial transmembrane potential in HT-29 cells. This attenuation of mitochondrial membrane potential (Δψm) was accompanied by increased production of ROS and depletion of GSH, an increase of Bax protein expression, and induced-activation of caspase-3/7 and caspase-9. These combined results suggest that NRAF induces mitochondrial-mediated apoptosis.
    Matched MeSH terms: Cell Nucleus Shape/drug effects
  11. Modified fields' stain: ideal to differentiate Dientamoeba fragilis and Blastocystis sp
    Ragavan AD, Govind SK
    Parasitol Res, 2015 Mar;114(3):1163-6.
    PMID: 25614298 DOI: 10.1007/s00436-014-4296-8
    Dientamoeba fragilis, a trichomonad parasite is usually found in the gastrointestinal tract of human, and it is known to be the cause for gastrointestinal disease. The parasite is globally distributed and mostly found in rural and urban areas. The parasite is found in humans and nonhuman primates such as the macaques, baboons, and gorillas. Often, the parasite is confused with another largely found organism in stools called Blastocystis sp. especially when seen directly under light microscopy on culture samples containing both parasites. Both sometimes are seen with two nuclei with sizes tending to be similar which complicates identification. Stools were collected fresh from nine previously diagnosed persons infected with D. fragilis who also were found to be positive for Blastocystis sp. Samples were then cultured in Loeffler's medium and were stained with Giemsa, iron hematoxylin, and modified Fields' (MF) stain, respectively. D. fragilis was differentiated from Blastocystis sp. when stained with MF stain by the presence of a thinner outer membrane with clearly demarcated nuclei in the center of the cell whilst Blastocystis sp. had a darker and thicker stained outer membrane with the presence of two nuclei. The staining contrast was more evident with modified Fields' stain when compared with the other two. The simplicity in preparing the stain as well as the speed of the staining procedure make MF stain an ideal alternate. The modified Fields' stain is faster and easier to prepare when compared to the other two stains. MF stain provides a better contrast differentiating the two organisms and therefore provides a more reliable diagnostic method to precisely identify one from the other especially when cultures show mixed infections.
    Matched MeSH terms: Cell Nucleus
  12. Plasmodium hylobati: a malaria parasite of the gibbon
    Collins WE, Contacos PG, Garnham PC, Warren M, Skinner JC
    J Parasitol, 1972 Feb;58(1):123-8.
    PMID: 4335047
    Matched MeSH terms: Cell Nucleus
  13. Fulltext Subditine, a new monoterpenoid indole alkaloid from bark of Nauclea subdita (Korth.) Steud. induces apoptosis in human prostate cancer cells
    Liew SY, Looi CY, Paydar M, Cheah FK, Leong KH, Wong WF, et al.
    PLoS One, 2014;9(2):e87286.
    PMID: 24551054 DOI: 10.1371/journal.pone.0087286
    In this study, a new apoptotic monoterpenoid indole alkaloid, subditine (1), and four known compounds were isolated from the bark of Nauclea subdita. Complete (1)H- and (13)C- NMR data of the new compound were reported. The structures of isolated compounds were elucidated with various spectroscopic methods such as 1D- and 2D- NMR, IR, UV and LCMS. All five compounds were screened for cytotoxic activities on LNCaP and PC-3 human prostate cancer cell-lines. Among the five compounds, the new alkaloid, subditine (1), demonstrated the most potent cell growth inhibition activity and selective against LNCaP with an IC50 of 12.24±0.19 µM and PC-3 with an IC50 of 13.97±0.32 µM, compared to RWPE human normal epithelial cell line (IC50 = 30.48±0.08 µM). Subditine (1) treatment induced apoptosis in LNCaP and PC-3 as evidenced by increased cell permeability, disruption of cytoskeletal structures and increased nuclear fragmentation. In addition, subditine (1) enhanced intracellular reactive oxygen species (ROS) production, as reflected by increased expression of glutathione reductase (GR) to scavenge damaging free radicals in both prostate cancer cell-lines. Excessive ROS could lead to disruption of mitochondrial membrane potential (MMP), release of cytochrome c and subsequent caspase 9, 3/7 activation. Further Western blot analyses showed subditine (1) induced down-regulation of Bcl-2 and Bcl-xl expression, whereas p53 was up-regulated in LNCaP (p53-wild-type), but not in PC-3 (p53-null). Overall, our data demonstrated that the new compound subditine (1) exerts anti-proliferative effect on LNCaP and PC-3 human prostate cancer cells through induction of apoptosis.
    Matched MeSH terms: Cell Nucleus/drug effects; Cell Nucleus/metabolism
  14. Fulltext Highly pathogenic avian influenza virus nucleoprotein interacts with TREX complex adaptor protein Aly/REF
    Balasubramaniam VR, Hong Wai T, Ario Tejo B, Omar AR, Syed Hassan S
    PLoS One, 2013;8(9):e72429.
    PMID: 24073193 DOI: 10.1371/journal.pone.0072429
    We constructed a novel chicken (Gallus gallus) lung cDNA library fused inside yeast acting domain vector (pGADT7). Using yeast two-hybrid screening with highly pathogenic avian influenza (HPAI) nucleoprotein (NP) from the strain (A/chicken/Malaysia/5858/2004(H5N1)) as bait, and the Gallus gallus lung cDNA library as prey, a novel interaction between the Gallus gallus cellular RNA export adaptor protein Aly/REF and the viral NP was identified. This interaction was confirmed and validated with mammalian two hybrid studies and co-immunoprecipitation assay. Cellular localization studies using confocal microscopy showed that NP and Aly/REF co-localize primarily in the nucleus. Further investigations by mammalian two hybrid studies into the binding of NP of other subtypes of influenza virus such as the swine A/New Jersey/1976/H1N1 and pandemic A/Malaysia/854/2009(H1N1) to human Aly/REF, also showed that the NP of these viruses interacts with human Aly/REF. Our findings are also supported by docking studies which showed tight and favorable binding between H5N1 NP and human Aly/REF, using crystal structures from Protein Data Bank. siRNA knockdown of Aly/REF had little effect on the export of HPAI NP and other viral RNA as it showed no significant reduction in virus titer. However, UAP56, another component of the TREX complex, which recruits Aly/REF to mRNA was found to interact even better with H5N1 NP through molecular docking studies. Both these proteins also co-localizes in the nucleus at early infection similar to Aly/REF. Intriguingly, knockdown of UAP56 in A549 infected cells shows significant reduction in viral titer (close to 10 fold reduction). Conclusively, our study have opened new avenues for research of other cellular RNA export adaptors crucial in aiding viral RNA export such as the SRSF3, 9G8 and ASF/SF2 that may play role in influenza virus RNA nucleocytoplasmic transport.
    Matched MeSH terms: Cell Nucleus/genetics; Active Transport, Cell Nucleus
  15. Styryl-lactone goniothalamin inhibits TNF-α-induced NF-κB activation
    Orlikova B, Schumacher M, Juncker T, Yan CC, Inayat-Hussain SH, Hajjouli S, et al.
    Food Chem Toxicol, 2013 Sep;59:572-8.
    PMID: 23845509 DOI: 10.1016/j.fct.2013.06.051
    (R)-(+)-Goniothalamin (GTN), a styryl-lactone isolated from the medicinal plant Goniothalamus macrophyllus, exhibits pharmacological activities including cytotoxic and anti-inflammatory effects. In this study, GTN modulated TNF-α induced NF-κB activation. GTN concentrations up to 20 μM showed low cytotoxic effects in K562 chronic myelogenous leukemia and in Jurkat T cells. Importantly, at these concentrations, no cytotoxicity was observed in healthy peripheral blood mononuclear cells. Our results confirmed that GTN inhibited tumor necrosis factor-α (TNF-α)-induced NF-κB activation in Jurkat and K562 leukemia cells at concentrations as low as 5 μM as shown by reporter gene assays and western blots. Moreover, GTN down-regulated translocation of the p50/p65 heterodimer to the nucleus, prevented binding of NF-κB to its DNA response element and reduced TNF-α-activated interleukin-8 (IL-8) expression. In conclusion, GTN inhibits TNF-α-induced NF-κB activation at non-apoptogenic concentrations in different leukemia cell models without presenting toxicity towards healthy blood cells underlining the anti-leukemic potential of this natural compound.
    Matched MeSH terms: Cell Nucleus/drug effects; Cell Nucleus/metabolism
  16. Diacerein-mediated inhibition of IL-6/IL-6R signaling induces apoptotic effects on breast cancer
    Bharti R, Dey G, Ojha PK, Rajput S, Jaganathan SK, Sen R, et al.
    Oncogene, 2016 Jul 28;35(30):3965-75.
    PMID: 26616855 DOI: 10.1038/onc.2015.466
    Interleukin-6 (IL-6) signaling network has been implicated in oncogenic transformations making it attractive target for the discovery of novel cancer therapeutics. In this study, potent antiproliferative and apoptotic effect of diacerein were observed against breast cancer. In vitro apoptosis was induced by this drug in breast cancer cells as verified by increased sub-G1 population, LIVE/DEAD assay, cell cytotoxicity and presence of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells, as well as downregulation of antiapoptotic proteins Bcl-2 and Bcl-xL and upregulation of apoptotic protein Bax. In addition, apoptosis induction was found to be caspase dependent. Further molecular investigations indicated that diacerein instigated apoptosis was associated with inhibition of IL-6/IL-6R autocrine signaling axis. Suppression of STAT3, MAPK and Akt pathways were also observed as a consequence of diacerein-mediated upstream inhibition of IL-6/IL-6R. Fluorescence study and western blot analysis revealed cytosolic accumulation of STAT3 in diacerein-treated cells. The docking study showed diacerein/IL-6R interaction that was further validated by competitive binding assay and isothermal titration calorimetry. Most interestingly, it was found that diacerein considerably suppressed tumor growth in MDA-MB-231 xenograft model. The in vivo antitumor effect was correlated with decreased proliferation (Ki-67), increased apoptosis (TUNEL) and inhibition of IL-6/IL-6R-mediated STAT3, MAPK and Akt pathway in tumor remnants. Taken together, diacerein offered a novel blueprint for cancer therapy by hampering IL-6/IL-6R/STAT3/MAPK/Akt network.
    Matched MeSH terms: Active Transport, Cell Nucleus
  17. Chemical composition and cytotoxic properties of Clinacanthus nutans root extracts
    Teoh PL, Cheng AY, Liau M, Lem FF, Kaling GP, Chua FN, et al.
    Pharm Biol, 2017 Dec;55(1):394-401.
    PMID: 27931178
    CONTEXT: Clinacanthus nutans Lindau (Acanthaceae) is a medicinal plant that has been reported to have anti-inflammatory, antiviral, antimicrobial and antivenom activities. In Malaysia, it has been widely claimed to be effective in various cancer treatments but scientific evidence is lacking.

    OBJECTIVE: This study investigates the chemical constituents, anti-proliferative, and apoptotic properties of C. nutans root extracts.

    MATERIALS AND METHODS: The roots were subjected to solvent extraction using methanol and ethyl acetate. The anti-proliferative effects of root extracts were tested at the concentrations of 10 to 50 μg/mL on MCF-7 and HeLa by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay for 72 h. Morphological changes were observed under light microscope. Pro-apoptotic effects of root extracts were examined using flow cytometric analysis and RT-PCR. The chemical compositions of root extracts were detected using GC-MS.

    RESULTS: The proliferation of MCF-7 cells was inhibited with the IC50 values of 35 and 30 μg/mL, respectively, for methanol and ethyl acetate root extracts. The average inhibition of HeLa cells was ∼25%. Induction of apoptosis in MCF-7 was supported by chromatin condensation, down-regulation of BCL2 and unaltered expression of BAX. However, only ethyl acetate extract caused the loss of mitochondrial membrane potential. GC-MS analysis revealed the roots extracts were rich with terpenoids and phytosterols.

    DISCUSSION AND CONCLUSIONS: The results demonstrated that root extracts promote apoptosis by suppressing BCL2 via mitochondria-dependent or independent manner. The identified compounds might work solely or cooperatively in regulating apoptosis. However, further studies are required to address this.

    Matched MeSH terms: Cell Nucleus Shape/drug effects
  18. The aminopeptidase inhibitor, z-L-CMK, is toxic and induces cell death in Jurkat T cells through oxidative stress
    Yeo EH, Goh WL, Chow SC
    Toxicol. Mech. Methods, 2018 Mar;28(3):157-166.
    PMID: 28849708 DOI: 10.1080/15376516.2017.1373882
    The leucine aminopeptidase inhibitor, benzyloxycarbonyl-leucine-chloromethylketone (z-L-CMK), was found to be toxic and readily induce cell death in Jurkat T cells. Dose-response studies show that lower concentration of z-L-CMK induced apoptosis in Jurkat T cells whereas higher concentration causes necrosis. In z-L-CMK-induced apoptosis, both the initiator caspases (-8 and -9) and effector caspases (-3 and -6) were processed to their respective subunits. However, the caspases remained intact in z-L-CMK-induced necrosis. The caspase inhibitor, z-VAD-FMK inhibited z-L-CMK-mediated apoptosis and caspase processing but has no effect on z-L-CMK-induced necrosis in Jurkat T cells. The high mobility group protein B1 (HMGB1) protein was found to be released into the culture medium by the necrotic cells and not the apoptotic cells. These results indicate that the necrotic cell death mediated by z-L-CMK at high concentrations is via classical necrosis rather than secondary necrosis. We also demonstrated that cell death mediated by z-L-CMK was associated with oxidative stress via the depletion of intracellular glutathione (GSH) and increase in reactive oxygen species (ROS), which was blocked by N-acetyl cysteine. Taken together, the results demonstrated that z-L-CMK is toxic to Jurkat T cells and induces apoptosis at low concentrations, while at higher concentrations the cells die of necrosis. The toxic side effects in Jurkat T cells mediated by z-L-CMK are associated with oxidative stress via the depletion of GSH and accumulation of ROS.
    Matched MeSH terms: Cell Nucleus Shape/drug effects
  19. Mitochondrial targeting of bilirubin regulatory enzymes: An adaptive response to oxidative stress
    Muhsain SN, Lang MA, Abu-Bakar A
    Toxicol Appl Pharmacol, 2015 Jan 1;282(1):77-89.
    PMID: 25478736 DOI: 10.1016/j.taap.2014.11.010
    The intracellular level of bilirubin (BR), an endogenous antioxidant that is cytotoxic at high concentrations, is tightly controlled within the optimal therapeutic range. We have recently described a concerted intracellular BR regulation by two microsomal enzymes: heme oxygenase 1 (HMOX1), essential for BR production and cytochrome P450 2A5 (CYP2A5), a BR oxidase. Herein, we describe targeting of these enzymes to hepatic mitochondria during oxidative stress. The kinetics of microsomal and mitochondrial BR oxidation were compared. Treatment of DBA/2J mice with 200mgpyrazole/kg/day for 3days increased hepatic intracellular protein carbonyl content and induced nucleo-translocation of Nrf2. HMOX1 and CYP2A5 proteins and activities were elevated in microsomes and mitoplasts but not the UGT1A1, a catalyst of BR glucuronidation. A CYP2A5 antibody inhibited 75% of microsomal BR oxidation. The inhibition was absent in control mitoplasts but elevated to 50% after treatment. An adrenodoxin reductase antibody did not inhibit microsomal BR oxidation but inhibited 50% of mitochondrial BR oxidation. Ascorbic acid inhibited 5% and 22% of the reaction in control and treated microsomes, respectively. In control mitoplasts the inhibition was 100%, which was reduced to 50% after treatment. Bilirubin affinity to mitochondrial and microsomal CYP2A5 enzyme is equally high. Lastly, the treatment neither released cytochrome c into cytoplasm nor dissipated membrane potential, indicating the absence of mitochondrial membrane damage. Collectively, the observations suggest that BR regulatory enzymes are recruited to mitochondria during oxidative stress and BR oxidation by mitochondrial CYP2A5 is supported by mitochondrial mono-oxygenase system. The induced recruitment potentially confers membrane protection.
    Matched MeSH terms: Active Transport, Cell Nucleus
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