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Oogai S, Fukuta M, Inafuku M, Oku H. Isolation and characterization of mimosine degrading enzyme from Arthrobacter sp. Ryudai-S1. World J Microbiol Biotechnol 2022; 38:172. [PMID: 35908235 DOI: 10.1007/s11274-022-03344-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 06/21/2022] [Indexed: 11/29/2022]
Abstract
Leucaena leucocephala growing in the tropics and subtropics serves as potential forage for livestock because its foliage is rich in protein, fiber, and minerals. However, its use for livestock feed has been hindered by toxic nonprotein amino acid mimosine. Therefore, it is necessary to develop a method to reduce or eliminate mimosine from foliage. A previous study found that the fermentation of L. leucocephala foliage reduced the mimosine content and prompted the authors to isolate potent mimosine degrading microorganisms and characterize the mimosinase for the complete elimination of mimosine in the L. leucocephala foliage. The soil screening of the L. leucocephala tree surroundings led to the isolation of Arthrobacter sp. Ryudai-S1, which can degrade and assimilate mimosine as a nitrogen and carbon source. Mimosinase in this strain was found to be thermostable and showed strong activity. Docking model's inspection and the interaction energy calculation between mimosine-pyridoxal-5'-phosphate (PLP) complex and the active site of this enzyme identified 11 important amino acid residues that stabilized the binding. Of these amino acid residues, mutation experiment suggested that Tyr-263' and Phe-34 stabilizes the substrate binding and play a critical role in guiding the substrate to proper positions to accomplish high catalytic efficacy and selectivity. These observations suggest that Arthrobacter sp. Ryudai-S1 could be potentially useful for the development of L. leucocephala feed with reduced mimosine content.
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Affiliation(s)
- Shigeki Oogai
- The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24, Ko-rimoto, Kagoshima, 890-8580, Japan
| | - Masakazu Fukuta
- The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24, Ko-rimoto, Kagoshima, 890-8580, Japan.,Faculty of Agriculture, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Nakagami-gun, Okinawa, 903-0213, Japan
| | - Masashi Inafuku
- Faculty of Agriculture, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Nakagami-gun, Okinawa, 903-0213, Japan
| | - Hirosuke Oku
- The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24, Ko-rimoto, Kagoshima, 890-8580, Japan. .,Molecular Biotechnology Group, Center of Molecular Bioscience, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Nakagami-gun, Okinawa, 903-0213, Japan.
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Abstract
Objectives: Prooxidant properties of iron-binding hydroxypyridone compounds including deferiprone and mimosine were analyzed. Methods: Hydroxypyridone/iron-dependent production of reactive oxygen species was evidenced by the inactivation of aconitase, the most sensitive enzyme to oxidative stress in permeabilized yeast cells. Results and Discussion: Deferiprone and mimosine produced reactive oxygen species in the presence of ferrous sulfate. The inactivation required sodium azide the inhibitor of catalase, and addition of TEMPOL, a scavenger of superoxide radical, protected aconitase from the inactivation, suggesting that the superoxide radical produced from the hydroxypyridone/iron complex is responsible for the inactivation of aconitase. A principal role of superoxide radical was further supported by the finding that the hydroxypyridone/iron complex can inactivate aconitase in the presence of cyanide the inhibitor of superoxide dismutase. Deferiprone and mimosine stimulated the Fe2+ oxidation, resulting in the one-electron reduction of oxygen to form superoxide anion, which can inactivate aconitase by oxidizing the prosthetic iron-sulfur cluster. Mimosine further stimulated the ascorbate/iron-dependent formation of 8-hydroxy-2′-deoxyguanosine in DNA. Conclusion: Biological toxicity of mimosine and deferiprone reported previously can be accounted for by the prooxidant properties of hydroxypyridone compounds: coordination complex with iron generates reactive oxygen species resulting in the disturbance of mitochondrial energy metabolism and DNA damage.
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Affiliation(s)
- Keiko Murakami
- Department of Biochemistry, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Masataka Yoshino
- Department of Biochemistry, Aichi Medical University School of Medicine, Nagakute, Japan
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Oogai S, Fukuta M, Watanabe K, Inafuku M, Oku H. Molecular characterization of mimosinase and cystathionine β-lyase in the Mimosoideae subfamily member Mimosa pudica. JOURNAL OF PLANT RESEARCH 2019; 132:667-680. [PMID: 31368041 DOI: 10.1007/s10265-019-01128-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 07/27/2019] [Indexed: 06/10/2023]
Abstract
Mimosinase degrades the non-protein amino acid mimosine and is thought to have evolved from cystathionine β-lyase (CBL) via gene duplication. However, no study has, to date, compared the molecular characteristics of mimosinase and CBL. We therefore cloned mimosinase and CBL from the Mimosoideae subfamily member Mimosa pudica (Mp) and explored the molecular relationship between mimosinase and CBL for the first time. The recombinant Mp mimosinase degraded both mimosine and cystathionine with a much higher turnover number (kcat) for mimosine compared with cystathionine, and Mp CBL utilized only cystathionine as a substrate. The critical residues implicated in the substrate binding of Arabidopsis thaliana CBL (Tyr-127, Arg-129, Tyr-181, and Arg-440) were highly conserved in both Mp mimosinase and CBL. However, homology modeling and molecular simulation of these enzymes predicted variations in the residues that interact with substrates. A mutation experiment on Mp mimosinase revealed that the disruption of a disulfide bond in the vicinity of the pyridoxal-5'-phosphate domain increased the enzyme's preference toward cystathionine. Treatment of Mp mimosinase with a disulfide-cleavage agent also decreased mimosinase activity. Furthermore, mutation near the conserved binding residue altered the substrate preference between mimosine and cystathionine. Molecular dynamics simulations of Mp mimosinase suggested a closer coordination of the residues that interact with mimosine at the active site compared with cystathionine, indicating a more compact pocket size for mimosine degradation. This study thus may provide new insights into the molecular diversification of CBL, a C-S lyase, into the C-N lyase mimosinase in the Mimosoideae subfamily.
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Affiliation(s)
- Shigeki Oogai
- The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24, Ko-rimoto, Kagoshima, 890-8580, Japan
| | - Masakazu Fukuta
- The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24, Ko-rimoto, Kagoshima, 890-8580, Japan
- Faculty of Agriculture, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Nakagami-gun, Okinawa, 903-0213, Japan
| | - Keiichi Watanabe
- The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24, Ko-rimoto, Kagoshima, 890-8580, Japan
- Faculty of Agriculture, Saga University, 1, Honjo-machi, Saga, 840-8502, Japan
| | - Masashi Inafuku
- Molecular Biotechnology Group, Center of Molecular Bioscience, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa, 903-0213, Japan
| | - Hirosuke Oku
- The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24, Ko-rimoto, Kagoshima, 890-8580, Japan.
- Molecular Biotechnology Group, Center of Molecular Bioscience, University of the Ryukyus, Senbaru 1, Nishihara, Okinawa, 903-0213, Japan.
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Kyriakou S, Mitsiogianni M, Mantso T, Cheung W, Todryk S, Veuger S, Pappa A, Tetard D, Panayiotidis MI. Anticancer activity of a novel methylated analogue of L-mimosine against an in vitro model of human malignant melanoma. Invest New Drugs 2019; 38:621-633. [PMID: 31240512 PMCID: PMC7211211 DOI: 10.1007/s10637-019-00809-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 06/05/2019] [Indexed: 12/18/2022]
Abstract
The anticancer activity of a series of novel synthesized, hydroxypyridone-based metal chelators (analogues of L-mimosine) was evaluated in an in vitro model of melanoma consisting of malignant melanoma (A375), non-melanoma epidermoid carcinoma (A431) and immortalized non-malignant keratinocyte (HaCaT) cells. More specifically, we have demonstrated that the L-enantiomer of a methylated analogue of L-mimosine (compound 22) can exert a potent anticancer effect in A375 cells when compared to either A431 or HaCaT cells. Moreover, we have demonstrated that this analogue has the ability to i) promote increased generation of reactive oxygen species (ROS), ii) activate both intrinsic and extrinsic apoptosis and iii) induce perturbations in cell cycle growth arrest. Our data highlights the potential of compound 22 to act as a promising therapeutic agent against an in vitro model of human malignant melanoma.
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Affiliation(s)
- Sotiris Kyriakou
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne, UK
| | - Melina Mitsiogianni
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne, UK
| | - Theodora Mantso
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne, UK
| | - William Cheung
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne, UK
| | - Stephen Todryk
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne, UK
| | - Stephany Veuger
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne, UK
| | - Aglaia Pappa
- Department of Molecular Biology & Genetics, Democritus University of Thrace, Alexandroupolis, Greece
| | - David Tetard
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne, UK
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Identifying and targeting cancer-specific metabolism with network-based drug target prediction. EBioMedicine 2019; 43:98-106. [PMID: 31126892 PMCID: PMC6558238 DOI: 10.1016/j.ebiom.2019.04.046] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 04/24/2019] [Accepted: 04/24/2019] [Indexed: 12/12/2022] Open
Abstract
Background Metabolic rewiring allows cancer cells to sustain high proliferation rates. Thus, targeting only the cancer-specific cellular metabolism will safeguard healthy tissues. Methods We developed the very efficient FASTCORMICS RNA-seq workflow (rFASTCORMICS) to build 10,005 high-resolution metabolic models from the TCGA dataset to capture metabolic rewiring strategies in cancer cells. Colorectal cancer (CRC) was used as a test case for a repurposing workflow based on rFASTCORMICS. Findings Alternative pathways that are not required for proliferation or survival tend to be shut down and, therefore, tumours display cancer-specific essential genes that are significantly enriched for known drug targets. We identified naftifine, ketoconazole, and mimosine as new potential CRC drugs, which were experimentally validated. Interpretation The here presented rFASTCORMICS workflow successfully reconstructs a metabolic model based on RNA-seq data and successfully predicted drug targets and drugs not yet indicted for colorectal cancer. Fund This study was supported by the University of Luxembourg (IRP grant scheme; R-AGR-0755-12), the Luxembourg National Research Fund (FNR PRIDE PRIDE15/10675146/CANBIO), the Fondation Cancer (Luxembourg), the European Union‘s Horizon2020 research and innovation programme under the Marie Sklodowska- Curie grant agreement No 642295 (MEL-PLEX), and the German Federal Ministry of Education and Research (BMBF) within the project MelanomSensitivity (BMBF/BM/7643621).
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Nguyen BCQ, Tawata S. The Chemistry and Biological Activities of Mimosine: A Review. Phytother Res 2016; 30:1230-42. [PMID: 27213712 DOI: 10.1002/ptr.5636] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 04/05/2016] [Accepted: 04/12/2016] [Indexed: 12/14/2022]
Abstract
Mimosine [β-[N-(3-hydroxy-4-oxypyridyl)]-α-aminopropionic acid] is a non-protein amino acid found in the members of Mimosoideae family. There are a considerable number of reports available on the chemistry, methods for estimation, biosynthesis, regulation, and degradation of this secondary metabolite. On the other hand, over the past years of active research, mimosine has been found to have various biological activities such as anti-cancer, antiinflammation, anti-fibrosis, anti-influenza, anti-virus, herbicidal and insecticidal activities, and others. Mimosine is a leading compound of interest for use in the development of RAC/CDC42-activated kinase 1 (PAK1)-specific inhibitors for the treatment of various diseases/disorders, because PAK1 is not essential for the growth of normal cells. Interestingly, the new roles of mimosine in malignant glioma treatment, regenerative dentistry, and phytoremediation are being emerged. These identified properties indicate an exciting future for this amino acid. The present review is focused on the chemistry and recognized biological activities of mimosine in an attempt to draw a link between these two characteristics. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Binh Cao Quan Nguyen
- Department of Bioscience and Biotechnology, The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima, 890-0065, Japan.,PAK Research Center, Okinawa, 903-0213, Japan
| | - Shinkichi Tawata
- PAK Research Center, Okinawa, 903-0213, Japan.,Department of Bioscience and Biotechnology, Faculty of Agriculture, University of the Ryukyus, Senbaru 1, Nishihara-cho, Okinawa, 903-0213, Japan
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Akcakaya H, Dal F, Tok S, Cinar SA, Nurten R. K562 cells display different vulnerability to H2O2induced oxidative stress in differing cell cycle phases. Cell Biol Int 2014; 39:201-9. [DOI: 10.1002/cbin.10360] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 08/01/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Handan Akcakaya
- Department of Biophysics; Istanbul Medical Faculty; Istanbul University; Istanbul Turkey
| | - Fulya Dal
- Department of Biophysics; Istanbul Medical Faculty; Istanbul University; Istanbul Turkey
| | - Sabiha Tok
- Department of Biophysics; Istanbul Medical Faculty; Istanbul University; Istanbul Turkey
| | - Suzan-Adin Cinar
- Department of Immunology; Institute of Experimental Medicine; Istanbul University; Istanbul Turkey
| | - Rustem Nurten
- Department of Biophysics; Istanbul Medical Faculty; Istanbul University; Istanbul Turkey
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Zhang Y, Ren X, Shi M, Jiang Z, Wang H, Su Q, Liu Q, Li G, Jiang G. Downregulation of STAT3 and activation of MAPK are involved in the induction of apoptosis by HNK in glioblastoma cell line U87. Oncol Rep 2014; 32:2038-46. [PMID: 25175884 DOI: 10.3892/or.2014.3434] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 06/10/2014] [Indexed: 11/06/2022] Open
Abstract
Honokiol [3,5-di-(2-propenyl)-1,1-biphenyl-2,2-diol; HNK], a natural bioactive molecular compound isolated from the Magnolia officinalis, exhibits potent antitumor activity against a variety of human cancer cell lines. However, few studies have reported the antineoplastic effects of HNK on glioblastoma cells. It remains unknown how apoptosis is induced by HNK in glioblastoma cells and through which associated pathway this compound acts. The present study confirmed that HNK inhibited proliferation of glioblastoma cells by inducing a slight G0/G1 phase cell cycle arrest and apoptosis. We demonstrated for the first time that HNK triggered apoptosis of glioblastoma cells through both caspase-independent and caspase-dependent pathways, the latter including the extrinsic pathway and intrinsic pathway. Moreover, the inhibition of STAT3 signaling, ERK1/2 as well as activation of the p38 MAPK signaling pathway may be involved in apoptosis induced by HNK in U87 cells. Our findings suggest that HNK treatment could be a promising therapeutic strategy in human glioblastoma.
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Affiliation(s)
- Yubao Zhang
- Department of Neurosurgery, Qilu Hospital, Shandong University, Jinan, Shandong, P.R. China
| | - Xia Ren
- Key Laboratory for Rare and Uncommon Diseases, Key Laboratory for Tumor Immunology and Chinese Medicine Immunology of Shandong Province, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan, Shandong, P.R. China
| | - Meiyan Shi
- Key Laboratory for Rare and Uncommon Diseases, Key Laboratory for Tumor Immunology and Chinese Medicine Immunology of Shandong Province, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan, Shandong, P.R. China
| | - Zheng Jiang
- Department of Neurosurgery, Qilu Hospital, Shandong University, Jinan, Shandong, P.R. China
| | - Hengxiao Wang
- Key Laboratory for Rare and Uncommon Diseases, Key Laboratory for Tumor Immunology and Chinese Medicine Immunology of Shandong Province, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan, Shandong, P.R. China
| | - Qinghong Su
- Key Laboratory for Rare and Uncommon Diseases, Key Laboratory for Tumor Immunology and Chinese Medicine Immunology of Shandong Province, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan, Shandong, P.R. China
| | - Qinglin Liu
- Department of Neurosurgery, Qilu Hospital, Shandong University, Jinan, Shandong, P.R. China
| | - Gang Li
- Department of Neurosurgery, Qilu Hospital, Shandong University, Jinan, Shandong, P.R. China
| | - Guosheng Jiang
- Key Laboratory for Rare and Uncommon Diseases, Key Laboratory for Tumor Immunology and Chinese Medicine Immunology of Shandong Province, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan, Shandong, P.R. China
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Qiao S, Fan K, Iwashita T, Ichihara M, Yoshino M, Takahashi M. The involvement of reactive oxygen species derived from NADPH oxidase-1 activation on the constitutive tyrosine auto-phosphorylation of RET proteins. Free Radic Res 2014; 48:427-34. [DOI: 10.3109/10715762.2014.884278] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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ZHANG RUIJIAN, WANG RUIJUN, CHANG HONG, WU FEI, LIU CHUNTAO, DENG DONGFENG, FAN WENHAI. Downregulation of Ezh2 expression by RNA interference induces cell cycle arrest in the G0/G1 phase and apoptosis in U87 human glioma cells. Oncol Rep 2012; 28:2278-84. [DOI: 10.3892/or.2012.2033] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 08/17/2012] [Indexed: 11/05/2022] Open
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Li JY, Huang JY, Li M, Zhang H, Xing B, Chen G, Wei D, Gu PY, Hu WX. Anisomycin induces glioma cell death via down-regulation of PP2A catalytic subunit in vitro. Acta Pharmacol Sin 2012; 33:935-40. [PMID: 22684030 DOI: 10.1038/aps.2012.46] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
AIM To examine the effects of anisomycin on glioma cells and the related mechanisms in vitro. METHODS The U251 and U87 human glioblastoma cell lines were tested. The growth of the cells was analyzed using a CCK-8 cell viability assay. Apoptosis was detected using a flow cytometry assay. The expression of proteins and phosphorylated kinases was detected using Western blotting. RESULTS Treatment of U251 and U87 cells with anisomycin (0.01-8 μmol/L) inhibited the cell growth in time- and concentration-dependent manners (the IC(50) values at 48 h were 0.233±0.021 and 0.192±0.018 μmol/L, respectively). Anisomycin (4 μmol/L) caused 21.5%±2.2% and 25.3%±3.1% of apoptosis proportion, respectively, in U251 and U87 cells. In the two cell lines, anisomycin (4 μmol/L) activated p38 MAPK and JNK, and inactivated ERK1/2. However, neither the p38 MAPK inhibitor SB203580 (10 μmol/L) nor the JNK inhibitor SP600125 (10 μmol/L) prevented anisomycin-induced cell death. On the other hand, anisomycin (4 μmol/L) reduced the level of PP2A/C subunit (catalytic subunit) in a time-dependent manner in the two cell lines. Treatment of the two cell lines with the PP2A inhibitor okadaic acid (100 nmol/L) caused marked cell death. CONCLUSION Anisomycin induces glioma cell death via down-regulation of PP2A catalytic subunit. The regulation of PP2A/C exression by anisomycin provides a clue to further study on its role in glioma therapy.
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Critical role of p53 upregulated modulator of apoptosis in benzyl isothiocyanate-induced apoptotic cell death. PLoS One 2012; 7:e32267. [PMID: 22359675 PMCID: PMC3281133 DOI: 10.1371/journal.pone.0032267] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 01/25/2012] [Indexed: 12/20/2022] Open
Abstract
Benzyl isothiocyanate (BITC), a constituent of edible cruciferous vegetables, decreases viability of cancer cells by causing apoptosis but the mechanism of cell death is not fully understood. The present study was undertaken to determine the role of Bcl-2 family proteins in BITC-induced apoptosis using MDA-MB-231 (breast), MCF-7 (breast), and HCT-116 (colon) human cancer cells. The B-cell lymphoma 2 interacting mediator of cell death (Bim) protein was dispensable for proapoptotic response to BITC in MCF-7 and MDA-MB-231 cells as judged by RNA interference studies. Instead, the BITC-treated MCF-7 and MDA-MB-231 cells exhibited upregulation of p53 upregulated modulator of apoptosis (PUMA) protein. The BITC-mediated induction of PUMA was relatively more pronounced in MCF-7 cells due to the presence of wild-type p53 compared with MDA-MB-231 with mutant p53. The BITC-induced apoptosis was partially but significantly attenuated by RNA interference of PUMA in MCF-7 cells. The PUMA knockout variant of HCT-116 cells exhibited significant resistance towards BITC-induced apoptosis compared with wild-type HCT-116 cells. Attenuation of BITC-induced apoptosis in PUMA knockout HCT-116 cells was accompanied by enhanced G2/M phase cell cycle arrest due to induction of p21 and down regulation of cyclin-dependent kinase 1 protein. The BITC treatment caused a decrease in protein levels of Bcl-xL (MCF-7 and MDA-MB-231 cells) and Bcl-2 (MCF-7 cells). Ectopic expression of Bcl-xL in MCF-7 and MDA-MB-231 cells and that of Bcl-2 in MCF-7 cells conferred protection against proapoptotic response to BITC. Interestingly, the BITC-treated MDA-MB-231 cells exhibited induction of Bcl-2 protein expression, and RNA interference of Bcl-2 in this cell line resulted in augmentation of BITC-induced apoptosis. The BITC-mediated inhibition of MDA-MB-231 xenograft growth in vivo was associated with the induction of PUMA protein in the tumor. In conclusion, the results of the present study indicate that Bim-independent apoptosis by BITC in cancer cells is mediated by PUMA.
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