Displaying publications 1 - 20 of 84 in total

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  1. Ali AM, Mackeen MM, Hamid M, Aun QB, Zauyah Y, Azimahtol HL, et al.
    Planta Med, 1997 Feb;63(1):81-3.
    PMID: 9063100
    The cytotoxicity of goniothalamin was found to be strong towards both cancerous (HGC-27, MCF-7, PANC-1, HeLa), and non-cancerous (3T3) cell lines, especially in cases of dividing cells. Drug exposure studies indicated that the cytotoxic action of goniothalamin was time- and dose-dependent. At the ultrastructural level, goniothalamin-induced cytotoxicity revealed a necrotic mode of cell death towards MCF-7 cells.
    Matched MeSH terms: Cell Death/drug effects*
  2. Inayat-Hussain SH, Rajab NF, Roslie H, Hussin AA, Ali AM, Annuar BO
    Med J Malaysia, 2004 May;59 Suppl B:176-7.
    PMID: 15468875
    Biomaterials intended for end-use application as bone-graft substitutes have to undergo safety evaluation. In this study, we investigated the in vitro cytotoxic effects especially to determine the mode of death of two hydroxyapatite compounds (HA2, HA3) which were synthesized locally. The methods used for cytotoxicity was the standard MTT assay whereas AO/PI staining was performed to determine the mode of cell death in HA treated L929 fibroblasts. Our results demonstrated that both HA2 and HA3 were not significantly cytotoxic as more than 75% cells after 72 hours treatment were viable. Furthermore, we found that the major mode of cell death in HA treated cells was apoptosis. In conclusion, our results demonstrated that these hydroxyapatite compounds are not cytotoxic where the mode of death was primarily via apoptosis.
    Matched MeSH terms: Cell Death/drug effects*
  3. Tan ML, Muhammad TS, Najimudin N, Sulaiman SF
    J Ethnopharmacol, 2005 Jan 15;96(3):375-83.
    PMID: 15619555
    Epipremnum pinnatum (L.) Engl. hexane extract produced a significant growth inhibition against T-47D breast carcinoma cells and analysis of cell death mechanisms indicated that the extract elicited a non-apoptotic programmed cell death. T-47D cells exposed to the extract at EC(50) concentration (72 h) for 24 h failed to demonstrate typical DNA fragmentation associated with apoptosis, as carried out using a modified TUNEL assay. In addition, acute exposure to the extract produced an insignificant regulation of caspase-3 and p53 mRNA expression but increased in the c-myc mRNA expression. Ultrastructural analysis using transmission electron microscope demonstrated distinct vacuolated cells, which strongly indicated a Type II non-apoptotic cell death although the changes in chromatin were also detected. The presence of non-apoptotic programmed cell death was then reconfirmed with annexin-V and propidium iodide staining. These findings suggested that up-regulation of c-myc mRNA expression may have contributed to the growth arrest and Type II non-apoptotic programmed cell death in the Epipremnum pinnatum (L.) Engl. hexane extract-treated T-47D cells.
    Matched MeSH terms: Cell Death/drug effects
  4. Kim TG, Hwi KK, Hung CS
    In Vivo, 2005 May-Jun;19(3):551-7.
    PMID: 15875775
    Andrographolide was extracted and purified from Andrographis panicula using hexane and water partitioning followed by ethyl acetate extraction and chromatography. It showed selective cytotoxicity to prostate cancer PC-3 cells in vitro. The morphological and biochemical changes induced by the extract in carcinoma PC-3 cell death were studied. In andrographolide-treated cells, evidence of apoptosis such as cell shrinkage and surface microvilli loss after 4-hour treatment and chromatin condensation and fragmentation in H&E-stained cells between 4 to 8 hours after treatment were observed. Under electron microscopy, membrane blebbing and apoptotic bodies formation were seen after 8-hour treatment. Using immunocytochemistry staining and cellular caspase-3 activity assay, andrographolide-treated cells showed considerable caspase-3 activation and caspase-8 in PC-3 cells at 4 and 2 hours after treatment, respectively. This suggests andrographolide-induced cell death was achieved through the apoptotic pathway, via the activation of an extrinsic caspase cascade.
    Matched MeSH terms: Cell Death/drug effects
  5. Er HM, Cheng EH, Radhakrishnan AK
    J Ethnopharmacol, 2007 Sep 25;113(3):448-56.
    PMID: 17698306
    The anti-proliferative effects of the aqueous and methanol extracts of leaves of Pereskia bleo (Kunth) DC (Cactaceae) against a mouse mammary cancer cell line (4T1) and a normal mouse fibroblast cell line (NIH/3T3) were evaluated under an optimal (in culture medium containing 10% foetal bovine serum (FBS)) and a sub-optimal (in culture medium containing 0.5% FBS) conditions. Under the optimal condition, the aqueous extract showed a significant (p<0.05) anti-proliferative effect at 200 microg/mL and 300 microg/mL in 4T1 cells and 300 microg/mL in NIH/3T3 cells, whereas the methanol extract did not show any notable anti-proliferative effect in these cell lines, at any of the concentrations tested. Under the sub-optimal condition, the aqueous extract showed a significant (p<0.05) anti-proliferative effect at 200 microg/mL and 300 microg/mL in NIH/3T3 cells, whilst the methanol extract showed a significant (p<0.05) anti-proliferative effect at 200 microg/mL and 300 microg/mL in both cell lines. An upward trend of apoptosis was observed in both 4T1 and NIH/3T3 cells treated with increasing concentrations of the aqueous extract. The level of apoptosis observed at all the concentrations of the aqueous extract tested was consistently higher than necrosis. There was a significant (p<0.05) increase in the level of necrosis observed in the 4T1 cells treated with 300 microg/mL of the methanol extract. Generally, the level of necrosis was noted to be higher than that of apoptosis in the methanol extract-treated cells. The mutagenicity assay performed showed that in the absence of S-9 liver metabolic activation, the extract was not mutagenic up to the concentration of 165 microg/mL . However, in the presence of S-9 liver metabolic activation, the aqueous extract was mutagenic at all the concentrations tested. This study shows that both the aqueous and methanol extracts of the leaves from Pereskia bleo (Kunth) DC (Cactaceae) do not have appreciable anti-proliferative effect on the 4T1 and NIH/3T3 cells as the EC(50) values obtained are greater than 50 microg/mL when tested under optimal culture condition. Moreover, the aqueous extract may form mutagenic compound(s) upon the metabolisation by liver enzymes.
    Matched MeSH terms: Cell Death/drug effects
  6. Inayat-Hussain SH, Wong LT, Chan KM, Rajab NF, Din LB, Harun R, et al.
    Toxicol Lett, 2009 Dec 15;191(2-3):118-22.
    PMID: 19698770 DOI: 10.1016/j.toxlet.2009.08.012
    Goniothalamin, a styryllactone, has been shown to induce cytotoxicity via apoptosis in several tumor cell lines. In this study, we have examined the potential role of several genes, which were stably transfected into T-cell lines and which regulate apoptosis in different ways, on goniothalamin-induced cell death. Overexpression of full-length receptor for activated protein C-kinase 1 (RACK-1) and pc3n3, which up-regulates endogenous RACK-1, in both Jurkat and W7.2 T cells resulted in inhibition of goniothalamin-induced cell death as assessed by MTT and clonogenic assays. However, overexpression of rFau (antisense sequence to Finkel-Biskis-Reilly murine sarcoma virus-associated ubiquitously expressed gene) in W7.2 cells did not confer resistance to goniothalamin-induced cell death. Etoposide, a clinically used cytotoxic agent, was equipotent in causing cytotoxicity in all the stable transfectants. Assessment of DNA damage by Comet assay revealed goniothalamin-induced DNA strand breaks as early as 1 h in vector control but this effect was inhibited in RACK-1 and pc3n3 stably transfected W7.2 cells. This data demonstrate that RACK-1 plays a crucial role in regulating cell death signalling pathways induced by goniothalamin.
    Matched MeSH terms: Cell Death/drug effects
  7. Yaacob NS, Hamzah N, Nik Mohamed Kamal NN, Zainal Abidin SA, Lai CS, Navaratnam V, et al.
    PMID: 20684795 DOI: 10.1186/1472-6882-10-42
    The leaves of Strobilanthes crispus (S. crispus) which is native to the regions of Madagascar to the Malay Archipelago, are used in folk medicine for their antidiabetic, diuretic, anticancer and blood pressure lowering properties. Crude extracts of this plant have been found to be cytotoxic to human cancer cell lines and protective against chemically-induced hepatocarcinogenesis in rats. In this study, the cytotoxicity of various sub-fractions of dichloromethane extract isolated from the leaves of S. crispus was determined and the anticancer activity of one of the bioactive sub-fractions, SC/D-F9, was further analysed in breast and prostate cancer cell lines.
    Matched MeSH terms: Cell Death/drug effects*
  8. Hong TB, Rahumatullah A, Yogarajah T, Ahmad M, Yin KB
    Int J Mol Sci, 2010;11(3):1057-69.
    PMID: 20479999 DOI: 10.3390/ijms11031057
    This study aims to elucidate the effects of chrysin on human ER-negative breast cancer cell line, MDA-MB-231. The study demonstrated that treatment of MDA-MB-231 cells with 20 microM chysin for 48 h significantly inhibited the growth of MDA-MB-231 cells and induced cytoplasmic lipid accumulation in the cells, but that the observed of cell death was not caused by apoptosis. The expression of PPARalpha mRNA in chrysin-treated MDA-MB-231 cells was significantly increased, which was likely associated to the proliferation of the cells post chrysin treatment.
    Matched MeSH terms: Cell Death/drug effects
  9. Ali R, Alabsi AM, Ali AM, Ideris A, Omar AR, Yusoff K, et al.
    Neurochem Res, 2011 Nov;36(11):2051-62.
    PMID: 21671106 DOI: 10.1007/s11064-011-0529-8
    Newcastle disease virus (NDV) is a member of genus Avulavirus within the family Paramyxoviridae. Interest of using NDV as an anticancer agent has arisen from its ability to kill tumor cells with limited toxicity to normal cells. In this investigation, the cytotolytic properties of NDV strain AF2240 were evaluated on brain tumor cell line, anaplastic astrocytoma (U-87MG), by using MTT assay. Cytological observations were studied using fluorescence microscopy and transmission electron microscopy to show the apoptogenic features of NDV on U-87MG. DNA laddering in agarose gel electrophoresis and terminal deoxyribonucleotide transferase-mediated dUTP-X nick end-labeling staining assay confirmed that the mode of cell death was by apoptosis. However, analysis of the cellular DNA content by flowcytometery showed that there was a loss of treated U-87MG cells in all cell cycle phases (G1, S and G2/M) accompanied with increasing in sub-G1 region (apoptosis peak). Early apoptosis was observed 6 h post-inoculation by annexin-V flow-cytometry method. It could be concluded that NDV strain AF2240 is a potent antitumor agent that induce apoptosis and its cytotoxicity increasing while increasing of time and virus titer.
    Matched MeSH terms: Cell Death/drug effects
  10. Choong CJ, Say YH
    Neurotoxicology, 2011 Dec;32(6):857-63.
    PMID: 21658409 DOI: 10.1016/j.neuro.2011.05.012
    α-Synuclein (α-Syn) plays a crucial role in the pathophysiology of Parkinson's disease (PD). α-Syn has been extensively studied in many neuronal cell-based PD models but has yielded mixed results. The objective of this study was to re-evaluate the dual cytotoxic/protective roles of α-Syn in dopaminergic SH-SY5Y cells. Stable SH-SY5Y cells overexpressing wild type or familial α-Syn mutants (A30P, E46K and A53T) were subjected to acute and chronic rotenone and maneb treatment. Compared with untransfected SH-SY5Y cells, wild type α-Syn attenuated rotenone and maneb-induced cell death along with an attenuation of toxin-induced mitochondrial membrane potential changes and Reactive Oxygen Species level, whereas the mutant α-Syn constructs exacerbated environmental toxins-induced cytotoxicity. After chronic treatment, wild type α-Syn but not the mutant variants was found to rescue cells from subsequent acute hydrogen peroxide insult. These results suggest that the fundamental property of wild type α-Syn may be protective, and such property may be lost by its familial PD mutations.
    Matched MeSH terms: Cell Death/drug effects
  11. Mah SH, Ee GC, Teh SS, Rahmani M, Lim YM, Go R
    Molecules, 2012 Jul 10;17(7):8303-11.
    PMID: 22781442 DOI: 10.3390/molecules17078303
    Our continuing studies on secondary metabolites from the stem bark of Calophyllum soulattri has led to the isolation of another new diprenylated xanthone, phylattrin (1), in addition to five other xanthones and two common sterols. The xanthones are soulattrin (2), caloxanthone C (3), macluraxanthone (4), brasixanthone B (5) and trapezifolixanthone (6) while the sterols are stigmasterol (7) and β-sitosterol (8). The structures of these compounds were determined on the basis of spectroscopic analyses such as 1D and 2D-NMR, HRESIMS, IR and UV. Compounds 1-7 exhibited moderate cytotoxic activities against SNU-1, HeLa, Hep G2, NCI-H23, K562, Raji, LS174T, IMR-32 and SK-MEL-28 cells.
    Matched MeSH terms: Cell Death/drug effects
  12. Lam KL, Yang KL, Sunderasan E, Ong MT
    Cell Prolif, 2012 Dec;45(6):577-85.
    PMID: 23046445 DOI: 10.1111/j.1365-2184.2012.00841.x
    OBJECTIVES: Latex from Hevea brasiliensis (natural rubber tree primarily cultivated for its rubber particles) has no known primary metabolic function, although its biological role is as a plant defence system. The present study has evaluated specific anti-proliferative effects of latex whole C-serum and its subfractions, on human cancer cell lines.

    MATERIALS AND METHODS: Cell viability assay using MTT, DNA fragmentation assay and real-time PCR were used to evaluate the cytotoxic effects of latex whole C-serum and its subfractions on the cell lines.

    RESULTS: MTT assay revealed very low LC(50) values, 2.0 and 280 ng/ml, for DCS and DCP treatments, respectively. DCS was proven to be more potent compared to DCP, in conferring specific anti-proliferative effects on the cancer cell lines. The study also indicated that anti-proliferative activity of pre-heated C-serum fractions diminished significantly.

    CONCLUSION: Although noteworthy cell death was reported, DNA fragmentation assay and real-time PCR confirmed that that induced by latex C-serum subfractions was not promoted via the classical apoptotic signalling pathway.

    Matched MeSH terms: Cell Death/drug effects
  13. Harun FB, Syed Sahil Jamalullail SM, Yin KB, Othman Z, Tilwari A, Balaram P
    ScientificWorldJournal, 2012;2012:439479.
    PMID: 22666123 DOI: 10.1100/2012/439479
    Eupatorium odoratum (EO) contains many biologically active compounds, the anticancer effects of which are not well documented. This study evaluates the cytotoxic effects and mechanism of action of EO extracts on MCF-7 and Vero cell lines. Evaluation of the cytotoxic activity using MTT assay, morphological alterations, and apoptosis were carried out. Autophagy was evaluated by LC3-A protein expression. Cytotoxic activity, membrane blebbing and ballooning at 24 hours, replacement by mass vacuolation, and double membrane vesicles mimicking autophagy and cell death were observed in the cancer cells. No apoptosis was observed by DNA fragmentation assay. Overexpression of LC3-A protein indicated autophagic cell death. Cell cycle analysis showed G0 and G2/M arrest. The Vero cells did not show significant cell death at concentrations <100 μg/mL. These results thus suggest that acetone and ethyl acetate extracts of EO induce cell death through induction of autophagy and hold potential for development as potential anticancer drugs.
    Matched MeSH terms: Cell Death/drug effects*
  14. Hasan S, Al Ali H, Al-Qubaisi M, Zobir Hussein M, Ismail M, Zainal Z, et al.
    Int J Nanomedicine, 2012;7:3351-63.
    PMID: 22848164 DOI: 10.2147/IJN.S30809
    A controlled-release formulation of an antihistamine, cetirizine, was synthesized using zinc-layered hydroxide as the host and cetirizine as the guest. The resulting well-ordered nanolayered structure, a cetirizine nanocomposite "CETN," had a basal spacing of 33.9 Å, averaged from six harmonics observed from X-ray diffraction. The guest, cetirizine, was arranged in a horizontal bilayer between the zinc-layered hydroxide (ZLH) inorganic interlayers. Fourier transform infrared spectroscopy studies indicated that the intercalation takes place without major change in the structure of the guest and that the thermal stability of the guest in the nanocomposites is markedly enhanced. The loading of the guest in the nanocomposites was estimated to be about 49.4% (w/w). The release study showed that about 96% of the guest could be released in 80 hours by phosphate buffer solution at pH 7.4 compared with about 97% in 73 hours at pH 4.8. It was found that release was governed by pseudo-second order kinetics. Release of histamine from rat basophilic leukemia cells was found to be more sensitive to the intercalated cetirizine in the CETN compared with its free counterpart, with inhibition of 56% and 29%, respectively, at 62.5 ng/mL. The cytotoxicity assay toward Chang liver cells line show the IC₅₀ for CETN and ZLH are 617 and 670 μg/mL, respectively.
    Matched MeSH terms: Cell Death/drug effects
  15. Komarasamy TV, Sekaran SD
    J Oleo Sci, 2012;61(4):227-39.
    PMID: 22450124
    Melanoma incidence and mortality have risen dramatically in recent years. No effective treatment for metastatic melanoma exists; hence currently, an intense effort for new drug evaluation is being carried out. In this study, we investigated the effects of a palm oil-derived nanopolymer called Bio-12 against human malignant melanoma. The nanopolymers of Bio-12 are lipid esters derived from a range of fatty acids of palm oil. Our study aims to identify the anti-proliferative properties of Bio-12 against human malignant melanoma cell line (MeWo) and to elucidate the mode of actions whereby Bio-12 brings about cell death. Bio-12 significantly inhibited the growth of MeWo cells in a concentration- and time- dependent manner with a median inhibitory concentration (IC₅₀) value of 1/25 dilution after 72 h but was ineffective on human normal skin fibroblasts (CCD-1059sk). We further investigated the mode of actions of Bio-12 on MeWo cells. Cell cycle flow cytometry demonstrated that MeWo cells treated with increasing concentrations of Bio-12 resulted in S-phase arrest, accompanied by the detection of sub-G1 content, indicative of apoptotic cell death. Induction of apoptosis was further confirmed via caspase (substrate) cleavage assay which showed induction of early apoptosis in MeWo cells. In addition, DNA strand breaks which are terminal event in apoptosis were evident through increase of TUNEL positive cells and formation of a characteristic DNA ladder on agarose gel electrophoresis. Moreover, treatment of MeWo cells with Bio-12 induced significant increase in lactate dehydrogenase (LDH) activity. These results show that Bio-12 possesses the ability to suppress proliferation of human malignant melanoma MeWo cells and this suppression is at least partly attributed to the initiation of the S-phase arrest, apoptosis and necrosis, suggesting that it is indeed worth for further investigations.
    Matched MeSH terms: Cell Death/drug effects
  16. Ho WY, Yeap SK, Ho CL, Rahim RA, Alitheen NB
    PLoS One, 2012;7(9):e44640.
    PMID: 22970274 DOI: 10.1371/journal.pone.0044640
    In comparison to monolayer cells, MCTS has been claimed as more suitable candidate for studying drug penetration due to the high resemblance to solid tumors. However, the cultivation of MCTS is cumbersome, time consuming, and most technique fail to generate spheroids with uniform sizes. Therefore, the application of spheroid cultures in high throughput screening has been rather limiting. Besides, the lack of a well established screening protocol method that is applicable to spheroid could also be attributed to this limitation. Here we report a simple way of cultivating homogenous MCTS cultures with compact and rigid structure from the MCF-7 cells. Besides, we had also made some modifications to the standard MTT assay to realize high throughput screening of these spheroids. Using the modified protocol, tamoxifen showed cytotoxicity effect towards MCTS cultures from MCF-7 with high consistency. The results correlated well with the cultures' response assessed by LDH release assay but the latter assay was not ideal for detecting a wide range of cytotoxicity due to high basal background reading. The MTT assay emerged as a better indicator to apoptosis event in comparison to the LDH release assay. Therefore, the method for spheroid generation and the modified MTT assay we reported here could be potentially applied to high throughput screening for response of spheroid cultures generated from MCF-7 as well as other cancer cell lines towards cytotoxic stimuli.
    Matched MeSH terms: Cell Death/drug effects
  17. Ramli NS, Eng Guan C, Nathan S, Vadivelu J
    PLoS One, 2012;7(9):e44104.
    PMID: 22970167 DOI: 10.1371/journal.pone.0044104
    Burkholderia pseudomallei, a Gram-negative saprophytic bacterium, is the causative agent of the potentially fatal melioidosis disease in humans. In this study, environmental parameters including temperature, nutrient content, pH and the presence of glucose were shown to play a role in in vitro biofilm formation by 28 B. pseudomallei clinical isolates, including four isolates with large colony variants (LCVs) and small colony variants (SCVs) morphotypes. Enhanced biofilm formation was observed when the isolates were tested in LB medium, at 30 °C, at pH 7.2, and in the presence of as little as 2 mM glucose respectively. It was also shown that all SVCs displayed significantly greater capacity to form biofilms than the corresponding LCVs when cultured in LB at 37 °C. In addition, octanoyl-homoserine lactone (C(8)-HSL), a quorum sensing molecule, was identified by mass spectrometry analysis in bacterial isolates referred to as LCV CTH, LCV VIT, SCV TOM, SCV CTH, 1 and 3, and the presence of other AHL's with higher masses; decanoyl-homoserine lactone (C(10)-HSL) and dodecanoyl-homoserine lactone (C(12)-HSL) were also found in all tested strain in this study. Last but not least, we had successfully acquired two Bacillus sp. soil isolates, termed KW and SA respectively, which possessed strong AHLs degradation activity. Biofilm formation of B. pseudomallei isolates was significantly decreased after treated with culture supernatants of KW and SA strains, demonstrating that AHLs may play a role in B. pseudomallei biofilm formation.
    Matched MeSH terms: Cell Death/drug effects
  18. Teh SS, Ee GC, Mah SH, Lim YM, Ahmad Z
    Molecules, 2013 Feb 04;18(2):1985-94.
    PMID: 23381024 DOI: 10.3390/molecules18021985
    The cytotoxic structure-activity relationships among a series of xanthone derivatives from Mesua beccariana, Mesua ferrea and Mesua congestiflora were studied. Eleven xanthone derivatives identified as mesuarianone (1), mesuasinone (2), mesuaferrin A (3), mesuaferrin B (4), mesuaferrin C (5), 6-deoxyjacareubin (6), caloxanthone C (7), macluraxanthone (8), 1,5-dihydroxyxanthone (9), tovopyrifolin C (10) and α-mangostin (11) were isolated from the three Mesua species. The human cancer cell lines tested were Raji, SNU-1, K562, LS-174T, SK-MEL-28, IMR-32, HeLa, Hep G2 and NCI-H23. Mesuaferrin A (3), macluraxanthone (8) and α-mangostin (11) showed strong cytotoxicities as they possess significant inhibitory effects against all the cell lines. The structure-activity relationship (SAR) study revealed that the diprenyl, dipyrano and prenylated pyrano substituent groups of the xanthone derivatives contributed towards the cytotoxicities.
    Matched MeSH terms: Cell Death/drug effects
  19. Jamaludin NS, Goh ZJ, Cheah YK, Ang KP, Sim JH, Khoo CH, et al.
    Eur J Med Chem, 2013 Sep;67:127-41.
    PMID: 23856069 DOI: 10.1016/j.ejmech.2013.06.038
    The synthesis and characterisation of R3PAu[S2CN((i)Pr)CH2CH2OH], for R = Ph (1), Cy (2) and Et (3)4, is reported. Compounds 1-3 are cytotoxic against the doxorubicin-resistant breast cancer cell line, MCF-7R, with 1 exhibiting greater potency and cytotoxicity than either of doxorubicin and cisplatin. Based on human apoptosis PCR-array analysis, caspase activities, DNA fragmentation, cell apoptotic assays, intracellular reactive oxygen species (ROS) measurements and human topoisomerase I inhibition, induction of apoptosis by 1, and necrosis by 2 and 3, are demonstrated, by both extrinsic and intrinsic pathways. Compound 1 activates the p53 gene, 2 activates only the p73 gene, whereas 3 activates both the p53 and p73 genes. Compounds 1 and 3 activate NF-κB, and each inhibits topoisomerase I.
    Matched MeSH terms: Cell Death/drug effects
  20. Liow KY, Chow SC
    Toxicol Appl Pharmacol, 2013 Nov 1;272(3):559-67.
    PMID: 23933532 DOI: 10.1016/j.taap.2013.07.022
    The cathepsin B inhibitor, benzyloxycarbonyl-phenylalanine-alanine-chloromethylketone (z-FA-CMK) was found to be toxic and readily induced cell death in the human T cell line, Jurkat, whereas two other analogs benzyloxycarbonyl-phenylalanine-alanine-fluoromethylketone (z-FA-FMK) and benzyloxycarbonyl-phenylalanine-alanine-diazomethylketone (z-FA-DMK) were not toxic. The toxicity of z-FA-CMK requires not only the CMK group, but also the presence of alanine in the P1 position and the benzyloxycarbonyl group at the N-terminal. Dose-response studies showed that lower concentrations of z-FA-CMK induced apoptosis in Jurkat T cells whereas higher concentrations induced necrosis. In z-FA-CMK-induced apoptosis, both initiator caspases (-8 and -9) and effector caspases (-3, -6 and -7) were processed to their respective subunits in Jurkat T cells. However, only the pro-form of the initiator caspases were reduced in z-FA-CMK-induced necrosis and no respective subunits were apparent. The caspase inihibitor benzyloxycarbonyl-valine-alanine-aspartic acid-(O-methyl)-fluoromehylketone (z-VAD-FMK) inhibits apoptosis and caspase processing in Jurkat T cells treated with low concentration of z-FA-CMK but has no effect on z-FA-CMK-induced necrosis and the loss of initiator caspases. This suggests that the loss of initiator caspases in Jurkat T cells during z-FA-CMK-induced necrosis is not a caspase-dependent process. Taken together, we have demonstrated that z-FA-CMK is toxic to Jurkat T cells and induces apoptosis at low concentrations, while at higher concentrations the cells die of necrosis.
    Matched MeSH terms: Cell Death/drug effects
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