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Chen S, Zhang W, Zhang H, Cui Y, Wang F, Wu J, Chao H, Yan D. The Complete Genome Sequence of a Gossypol-Degrading Bacterial Strain, Raoultella sp. YL01. Curr Microbiol 2023; 80:163. [PMID: 37012483 DOI: 10.1007/s00284-023-03204-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 01/23/2023] [Indexed: 04/05/2023]
Abstract
Cottonseed meal is an important source of plant protein for the meal fodder materials. But its usage in animal breeding industry is limited by a type of toxic phenol, gossypol, that has toxic effects on animal health. Microbial degradation is a promising way to lower down gossypol in cottonseed meal. However, the molecular mechanisms of bio-degradation of gossypol is still unclear. In this study we isolated a gossypol-degrading bacterial strain, YL01, and sequenced its complete genome via Oxford Nanopore sequencing method. There is a chromosome (5,737,005 bp) and a plasmid (136,446 bp) in YL01. 5489 protein coding genes in total were functionally annotated. 16S rRNA analysis showed that YL01 taxonomically belongs to the genus of Raoultella. YL01 is the first published complete genome sequence of microbes capable of gossypol degradation. Gene function annotation showed that 126 protein coding genes may involve in gossypol catabolism. Sequence similarity analysis showed that, as the only gossypol-degrading strain in the genus of Raoultella, YL01 uniquely holds 260 genes that are not possessed by other Raoultella strains. Our work gives a preliminary list for genes responsible for gossypol degradation but further investigations are needed to completely disclose this molecular processes.
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Affiliation(s)
- Si Chen
- School of of Life Sciences and Technology, Wuhan Polytechnic University, Wuhan, 430023, People's Republic of China
| | - Weishu Zhang
- School of of Life Sciences and Technology, Wuhan Polytechnic University, Wuhan, 430023, People's Republic of China
| | - Huiling Zhang
- School of of Life Sciences and Technology, Wuhan Polytechnic University, Wuhan, 430023, People's Republic of China
| | - Ying Cui
- School of of Life Sciences and Technology, Wuhan Polytechnic University, Wuhan, 430023, People's Republic of China
| | - Feng Wang
- School of of Life Sciences and Technology, Wuhan Polytechnic University, Wuhan, 430023, People's Republic of China
| | - Jing Wu
- School of of Life Sciences and Technology, Wuhan Polytechnic University, Wuhan, 430023, People's Republic of China
| | - Hongjun Chao
- School of of Life Sciences and Technology, Wuhan Polytechnic University, Wuhan, 430023, People's Republic of China.
| | - Dazhong Yan
- School of of Life Sciences and Technology, Wuhan Polytechnic University, Wuhan, 430023, People's Republic of China.
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Gossypol and Its Natural Derivatives: Multitargeted Phytochemicals as Potential Drug Candidates for Oncologic Diseases. Pharmaceutics 2022; 14:pharmaceutics14122624. [PMID: 36559116 PMCID: PMC9787675 DOI: 10.3390/pharmaceutics14122624] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 11/29/2022] Open
Abstract
Despite the vast amounts of research and remarkable discoveries that have been made in recent decades, cancer remains a leading cause of death and a major public health concern worldwide. Gossypol, a natural polyphenolic compound derived from the seeds, roots, and stems of cotton (Gossypium hirsutum L.), was first used as a male contraceptive agent. Due to its diverse biological properties, including antifertility, antiviral, antioxidant, antibacterial, antimalarial, and most notably antitumor activities, gossypol has been the subject of numerous studies. Nevertheless, no systematic review has been performed that analyzes the antineoplastic potential of gossypol and related natural compounds in an organ-specific manner while delineating the molecular mechanisms of action. Hence, we have performed an extensive literature search for anticancer properties of gossypol and their natural derivatives against various types of cancer cells utilizing PubMed, ScienceDirect, Google Scholar, and Scopus. The sources, distribution, chemical structure, and toxicity of gossypol and its constituents are briefly reviewed. Based on emerging evidence, gossypol and related compounds exhibit significant antineoplastic effects against various cancer types through the modulation of different cancer hallmarks and signaling pathways. Additionally, the synergistic activity of gossypol and its derivatives with chemotherapeutic agents has been observed. Our evaluation of the current literature suggests the potential of gossypol and its derivatives as multitargeting drug candidates to combat multiple human malignancies.
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Alhasawi MAI, Aatif M, Muteeb G, Alam MW, Oirdi ME, Farhan M. Curcumin and Its Derivatives Induce Apoptosis in Human Cancer Cells by Mobilizing and Redox Cycling Genomic Copper Ions. Molecules 2022; 27:molecules27217410. [PMID: 36364236 PMCID: PMC9659251 DOI: 10.3390/molecules27217410] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 10/25/2022] [Accepted: 10/26/2022] [Indexed: 11/06/2022] Open
Abstract
Turmeric spice contains curcuminoids, which are polyphenolic compounds found in the Curcuma longa plant’s rhizome. This class of molecules includes curcumin, demethoxycurcumin, and bisdemethoxycurcumin. Using prostate cancer cell lines PC3, LNCaP, DU145, and C42B, we show that curcuminoids inhibit cell proliferation (measured by MTT assay) and induce apoptosis-like cell death (measured by DNA/histone ELISA). A copper chelator (neocuproine) and reactive oxygen species scavengers (thiourea for hydroxyl radical, superoxide dismutase for superoxide anion, and catalase for hydrogen peroxide) significantly inhibit this reaction, thus demonstrating that intracellular copper reacts with curcuminoids in cancer cells to cause DNA damage via ROS generation. We further show that copper-supplemented media sensitize normal breast epithelial cells (MCF-10A) to curcumin-mediated growth inhibition, as determined by decreased cell proliferation. Copper supplementation results in increased expression of copper transporters CTR1 and ATP7A in MCF-10A cells, which is attenuated by the addition of curcumin in the medium. We propose that the copper-mediated, ROS-induced mechanism of selective cell death of cancer cells may in part explain the anticancer effects of curcuminoids.
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Affiliation(s)
| | - Mohammad Aatif
- Department of Public Health, College of Applied Medical Sciences, King Faisal University, Al-Ahsa 31982, Saudi Arabia
| | - Ghazala Muteeb
- Department of Nursing, College of Applied Medical Sciences, King Faisal University, Al-Ahsa 31982, Saudi Arabia
| | - Mir Waqas Alam
- Department of Physics, College of Science, King Faisal University, Al-Ahsa 31982, Saudi Arabia
| | - Mohamed El Oirdi
- Department of Basic Sciences, Preparatory Year Deanship, King Faisal University, Al-Ahsa 31982, Saudi Arabia
- Correspondence: (M.E.O.); (M.F.)
| | - Mohd Farhan
- Department of Basic Sciences, Preparatory Year Deanship, King Faisal University, Al-Ahsa 31982, Saudi Arabia
- Correspondence: (M.E.O.); (M.F.)
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Zeng Y, Ma J, Xu L, Wu D. Natural Product Gossypol and its Derivatives in Precision Cancer Medicine. Curr Med Chem 2019; 26:1849-1873. [PMID: 28545375 DOI: 10.2174/0929867324666170523123655] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 05/09/2017] [Accepted: 05/16/2017] [Indexed: 01/07/2023]
Abstract
Gossypol, a natural product extracted from the seed, roots, and stem of cotton, was initially used as a male contraceptive but was subsequently investigated as a novel antitumor agent. This review depicts the current status of gossypol and its derivatives as novel antitumor agents as well as presents their preparation and characteristics, especially of some gossypol Schiff bases, through quantitative and structural analysis. The main attractive target sites of gossypol and its derivatives are Bcl-2 family proteins containing the anti-apoptosis proteins Bcl-2 and Bcl-XL. The molecular mechanism of gossypol analogs not only involves cell apoptosis but also autophagy, cell cycle arrest, and other abnormal cellular phenomena. Gossypol and its derivatives exert antitumor effects on different cancer types in vitro and in vivo, and demonstrate synergistic effects with other chemo- and radio- therapeutic treatments. In addition, several nanocarriers have been designed to load gossypol or its derivatives in order to expand the range of their applications and evaluate their combination effects with other anti-tumor agents. This review may serve as a reference for the rational application of gossypol analogs as anti-tumor agents.
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Affiliation(s)
- Yun Zeng
- The Key Laboratory of Biomedical Information Engineering, Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Jingwen Ma
- The Key Laboratory of Biomedical Information Engineering, Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Liang Xu
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, United States.,Department of Radiation Oncology, University of Kansas Cancer Center, Kansas City, Kansas, United States
| | - Daocheng Wu
- The Key Laboratory of Biomedical Information Engineering, Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
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5
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Shen S, Wu Y, Li K, Wang Y, Wu J, Zeng Y, Wu D. Versatile hyaluronic acid modified AQ4N-Cu(II)-gossypol infinite coordination polymer nanoparticles: Multiple tumor targeting, highly efficient synergistic chemotherapy, and real-time self-monitoring. Biomaterials 2018; 154:197-212. [DOI: 10.1016/j.biomaterials.2017.11.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 10/26/2017] [Accepted: 11/02/2017] [Indexed: 01/10/2023]
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6
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Zafar A, Singh S, Naseem I. Cytotoxic activity of soy phytoestrogen coumestrol against human breast cancer MCF-7 cells: Insights into the molecular mechanism. Food Chem Toxicol 2017; 99:149-161. [PMID: 27913286 DOI: 10.1016/j.fct.2016.11.034] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 11/13/2016] [Accepted: 11/29/2016] [Indexed: 02/07/2023]
Abstract
Coumestrol is a phytoestrogen present in soybean products and recognized as potential cancer therapeutic agent against breast cancer. However, the clear molecular mechanism of anticancer-activity of coumestrol in breast carcinoma has not been reported. It is well established that copper levels are elevated in different malignancies. Therefore, the objective of this study was to investigate the copper-dependent cytotoxic action of coumestrol in human breast cancer MCF-7 cells. Results showed that coumestrol inhibited proliferation and induced apoptosis in MCF-7 cells, which was prevented by copper chelator neocuproine and ROS scavengers. Coumestrol treatment induced ROS generation coupled to DNA fragmentation, up-regulation of p53/p21, cell cycle arrest at G1/S phase, mitochondrial membrane depolarization and caspases 9/3 activation. All these effects were suppressed by ROS scavengers and neocuproine. These results suggest that coumestrol targets elevated copper for redox cycling to generate ROS leading to DNA fragmentation. DNA damage leads to p53 up-regulation which directs the cell cycle arrest at G1/S phase and promotes caspase-dependent apoptosis of MCF-7 cells. In conclusion, copper targeted ROS-mediated p53-dependent mechanism better explains the cytotoxic action of coumestrol in MCF-7 cells. Thus, targeting elevated copper levels might be a potential therapeutic strategy for selective cytotoxic action against malignant cells.
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Affiliation(s)
- Atif Zafar
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202002, Uttar Pradesh, India
| | - Swarnendra Singh
- Department of Dermatology and Venereology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110 029, India
| | - Imrana Naseem
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202002, Uttar Pradesh, India.
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Zubair H, Azim S, Khan HY, Ullah MF, Wu D, Singh AP, Hadi SM, Ahmad A. Mobilization of Intracellular Copper by Gossypol and Apogossypolone Leads to Reactive Oxygen Species-Mediated Cell Death: Putative Anticancer Mechanism. Int J Mol Sci 2016; 17:ijms17060973. [PMID: 27331811 PMCID: PMC4926505 DOI: 10.3390/ijms17060973] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/07/2016] [Accepted: 06/14/2016] [Indexed: 12/25/2022] Open
Abstract
There is compelling evidence that serum, tissue and intracellular levels of copper are elevated in all types of cancer. Copper has been suggested as an important co-factor for angiogenesis. It is also a major metal ion present inside the nucleus, bound to DNA bases, particularly guanine. We have earlier proposed that the interaction of phenolic-antioxidants with intracellular copper leads to the generation of reactive oxygen species (ROS) that ultimately serve as DNA cleaving agents. To further validate our hypothesis we show here that the antioxidant gossypol and its semi-synthetic derivative apogossypolone induce copper-mediated apoptosis in breast MDA-MB-231, prostate PC3 and pancreatic BxPC-3 cancer cells, through the generation of ROS. MCF10A breast epithelial cells refractory to the cytotoxic property of these compounds become sensitized to treatment against gossypol, as well as apogossypolone, when pre-incubated with copper. Our present results confirm our earlier findings and strengthen our hypothesis that plant-derived antioxidants mobilize intracellular copper instigating ROS-mediated cellular DNA breakage. As cancer cells exist under significant oxidative stress, this increase in ROS-stress to cytotoxic levels could be a successful anticancer approach.
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Affiliation(s)
- Haseeb Zubair
- Department of Biochemistry, Faculty of Life Sciences, AMU, Aligarh 202002, India.
- Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA.
| | - Shafquat Azim
- Department of Biochemistry, Faculty of Life Sciences, AMU, Aligarh 202002, India.
- Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA.
| | - Husain Yar Khan
- Department of Biochemistry, Faculty of Life Sciences, AMU, Aligarh 202002, India.
- UoN Chair of Oman's Medicinal Plants and Marine Natural Products, University of Nizwa, Birkat Al Mauz, PO Box 33, 616 Nizwa, Oman.
| | - Mohammad Fahad Ullah
- Department of Biochemistry, Faculty of Life Sciences, AMU, Aligarh 202002, India.
- Prince Fahad Research Chair, Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, University of Tabuk, P.O. Box 741, Tabuk-71491, Saudi Arabia.
| | - Daocheng Wu
- Key Laboratory of Biomedical Information Engineering of Education Ministry, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710048, China.
| | - Ajay Pratap Singh
- Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA.
| | - Sheikh Mumtaz Hadi
- Department of Biochemistry, Faculty of Life Sciences, AMU, Aligarh 202002, India.
| | - Aamir Ahmad
- Department of Oncologic Sciences, Mitchell Cancer Institute, University of South Alabama, Mobile, AL 36604, USA.
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Chai X, Bi Y, Sun S. Free fatty acids increase gossypol losses in soybean oil during heating. EUR J LIPID SCI TECH 2016. [DOI: 10.1002/ejlt.201400487] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Xiuhang Chai
- Lipid Technology and EngineeringSchool of Food Science and EngineeringHenan University of TechnologyZhengzhouHenanP. R. China
| | - Yanlan Bi
- Lipid Technology and EngineeringSchool of Food Science and EngineeringHenan University of TechnologyZhengzhouHenanP. R. China
| | - Shangde Sun
- Lipid Technology and EngineeringSchool of Food Science and EngineeringHenan University of TechnologyZhengzhouHenanP. R. China
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9
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Mobilization of Copper ions by Flavonoids in Human Peripheral Lymphocytes Leads to Oxidative DNA Breakage: A Structure Activity Study. Int J Mol Sci 2015; 16:26754-69. [PMID: 26569217 PMCID: PMC4661851 DOI: 10.3390/ijms161125992] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 10/29/2015] [Accepted: 10/30/2015] [Indexed: 11/16/2022] Open
Abstract
Epidemiological studies have linked dietary consumption of plant polyphenols with lower incidence of various cancers. In particular, flavonoids (present in onion, tomato and other plant sources) induce apoptosis and cytotoxicity in cancer cells. These can therefore be used as lead compounds for the synthesis of novel anticancer drugs with greater bioavailability. In the present study, we examined the chemical basis of cytotoxicity of flavonoids by studying the structure–activity relationship of myricetin (MN), fisetin (FN), quercetin (QN), kaempferol (KL) and galangin (GN). Using single cell alkaline gel electrophoresis (comet assay), we established the relative efficiency of cellular DNA breakage as MN > FN > QN > KL > GN. Also, we determined that the cellular DNA breakage was the result of mobilization of chromatin-bound copper ions and the generation of reactive oxygen species. The relative DNA binding affinity order was further confirmed using molecular docking and thermodynamic studies through the interaction of flavonoids with calf thymus DNA. Our results suggest that novel anti-cancer molecules should have ortho-dihydroxy groups in B-ring and hydroxyl groups at positions 3 and 5 in the A-ring system. Additional hydroxyl groups at other positions further enhance the cellular cytotoxicity of the flavonoids.
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Phytoagents for cancer management: regulation of nucleic acid oxidation, ROS, and related mechanisms. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:925804. [PMID: 24454991 PMCID: PMC3886269 DOI: 10.1155/2013/925804] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 09/27/2013] [Accepted: 10/05/2013] [Indexed: 12/28/2022]
Abstract
Accumulation of oxidized nucleic acids causes genomic instability leading to senescence, apoptosis, and tumorigenesis. Phytoagents are known to reduce the risk of cancer development; whether such effects are through regulating the extent of nucleic acid oxidation remains unclear. Here, we outlined the role of reactive oxygen species in nucleic acid oxidation as a driving force in cancer progression. The consequential relationship between genome instability and cancer progression highlights the importance of modulation of cellular redox level in cancer management. Current epidemiological and experimental evidence demonstrate the effects and modes of action of phytoagents in nucleic acid oxidation and provide rationales for the use of phytoagents as chemopreventive or therapeutic agents. Vitamins and various phytoagents antagonize carcinogen-triggered oxidative stress by scavenging free radicals and/or activating endogenous defence systems such as Nrf2-regulated antioxidant genes or pathways. Moreover, metal ion chelation by phytoagents helps to attenuate oxidative DNA damage caused by transition metal ions. Besides, the prooxidant effects of some phytoagents pose selective cytotoxicity on cancer cells and shed light on a new strategy of cancer therapy. The “double-edged sword” role of phytoagents as redox regulators in nucleic acid oxidation and their possible roles in cancer prevention or therapy are discussed in this review.
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11
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Novel pro-oxidant activity assay for polyphenols, vitamins C and E using a modified CUPRAC method. Talanta 2013; 115:583-9. [DOI: 10.1016/j.talanta.2013.06.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 06/01/2013] [Accepted: 06/06/2013] [Indexed: 01/18/2023]
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ApoG2 induces ER stress-dependent apoptosis in gastric cancer cells in vitro and its real-time evaluation by bioluminescence imaging in vivo. Cancer Lett 2013; 336:260-9. [DOI: 10.1016/j.canlet.2013.03.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 02/17/2013] [Accepted: 03/14/2013] [Indexed: 12/14/2022]
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13
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Zhou M, Zhang C, Wu Y, Tang Y. Metabolic engineering of gossypol in cotton. Appl Microbiol Biotechnol 2013; 97:6159-65. [PMID: 23775273 DOI: 10.1007/s00253-013-5032-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 05/31/2013] [Accepted: 05/31/2013] [Indexed: 11/24/2022]
Abstract
Cotton has long been known as a fiber plant. Besides the cotton fiber, the cottonseed oil and cottonseed protein are two other major products of cotton plants. However, the applications of the cottonseed oil and protein are limited because of the presence of toxic gossypol, which is unsafe for human and monogastric animal consumption. Meanwhile, gossypol in cotton increases the plant defense response to insect herbivores and pathogens. Consequently, gossypol has been extensively used in clinical trials in biomedical science. Over the last few years, major advances have occurred in both understanding and practice with regard to molecular regulation of gossypol pathway in cotton plant or hairy root culture. This review highlights a few major recent and ongoing developments in metabolic engineering of gossypol, as well as suggestions regarding further advances needed.
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Affiliation(s)
- Meiliang Zhou
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Zhongguancun South Street No 12, Haidian District, Beijing 100081, China
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Redox cycling of endogenous copper by thymoquinone leads to ROS-mediated DNA breakage and consequent cell death: putative anticancer mechanism of antioxidants. Cell Death Dis 2013; 4:e660. [PMID: 23744360 PMCID: PMC3698541 DOI: 10.1038/cddis.2013.172] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Plant-derived dietary antioxidants have attracted considerable interest in recent past for their chemopreventive and cancer therapeutic abilities in animal models. Thymoquinone (TQ) is the major bioactive constituent of volatile oil of Nigella sativa and has been shown to exert various pharmacological properties, such as anti-inflammatory, cardiovascular, analgesic, anti-neoplastic, anticancer and chemopreventive. Although several mechanisms have been suggested for the chemopreventive and anticancer activity of TQ, a clear mechanism of action of TQ has not been elucidated. TQ is a known antioxidant at lower concentrations and most of the studies elucidating the mechanism have centered on the antioxidant property. However, recent publications have shown that TQ may act as a prooxidant at higher concentrations. It is well known that plant-derived antioxidants can switch to prooxidants even at low concentrations in the presence of transition metal ions such as copper. It is well established that tissue, cellular and serum copper levels are considerably elevated in various malignancies. Copper is an important metal ion present in the chromatin and is closely associated with DNA bases, particularly guanine. Using human peripheral lymphocytes and comet assay, we first show that TQ is able to cause oxidative cellular DNA breakage. Such a DNA breakage can be inhibited by copper-chelating agents, neocuproine and bathocuproine, and scavengers of reactive oxygen species. Further, it is seen that TQ targets cellular copper in prostate cancer cell lines leading to a prooxidant cell death. We believe that such a prooxidant cytotoxic mechanism better explains the anticancer activity of plant-derived antioxidants.
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Cheng P, Ni Z, Dai X, Wang B, Ding W, Rae Smith A, Xu L, Wu D, He F, Lian J. The novel BH-3 mimetic apogossypolone induces Beclin-1- and ROS-mediated autophagy in human hepatocellular carcinoma [corrected] cells. Cell Death Dis 2013; 4:e489. [PMID: 23392177 PMCID: PMC3734844 DOI: 10.1038/cddis.2013.17] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Apogossypolone (ApoG2), a novel derivative of gossypol, exhibits superior antitumor activity in Bcl-2 transgenic mice, and induces autophagy in several cancer cells. However, the detailed mechanisms are not well known. In the present study, we showed that ApoG2 induced autophagy through Beclin-1- and reactive oxygen species (ROS)-dependent manners in human hepatocellular carcinoma (HCC) cells. Incubating the HCC cell with ApoG2 abrogated the interaction of Beclin-1 and Bcl-2/xL, stimulated ROS generation, increased phosphorylation of ERK and JNK, and HMGB1 translocation from the nucleus to cytoplasm while suppressing mTOR. Moreover, inhibition of the ROS-mediated autophagy by antioxidant N-acetyl-cysteine (NAC) potentiates ApoG2-induced apoptosis and cell killing. Our results show that ApoG2 induced protective autophagy in HCC cells, partly due to ROS generation, suggesting that antioxidant may serve as a potential chemosensitizer to enhance cancer cell death through blocking ApoG2-stimulated autophagy. Our novel insights may facilitate the rational design of clinical trials for Bcl-2-targeted cancer therapy.
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Affiliation(s)
- P Cheng
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Third Military Medical University, Chongqing, China
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