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Vuyyuri SB, Rinkinen J, Worden E, Shim H, Lee S, Davis KR. Ascorbic acid and a cytostatic inhibitor of glycolysis synergistically induce apoptosis in non-small cell lung cancer cells. PLoS One 2013; 8:e67081. [PMID: 23776707 PMCID: PMC3679078 DOI: 10.1371/journal.pone.0067081] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 05/15/2013] [Indexed: 12/28/2022] Open
Abstract
Ascorbic acid (AA) exhibits significant anticancer activity at pharmacologic doses achievable by parenteral administration that have minimal effects on normal cells. Thus, AA has potential uses as a chemotherapeutic agent alone or in combination with other therapeutics that specifically target cancer-cell metabolism. We compared the effects of AA and combinations of AA with the glycolysis inhibitor 3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3-PO) on the viability of three non-small cell lung cancer (NSCLC) cell lines to the effects on an immortalized lung epithelial cell line. AA concentrations of 0.5 to 5 mM caused a complete loss of viability in all NSCLC lines compared to a <10% loss of viability in the lung epithelial cell line. Combinations of AA and 3-PO synergistically enhanced cell death in all NSCLC cell lines at concentrations well below the IC50 concentrations for each compound alone. A synergistic interaction was not observed in combination treatments of lung epithelial cells and combination treatments that caused a complete loss of viability in NSCLC cells had modest effects on normal lung cell viability and reactive oxygen species (ROS) levels. Combination treatments induced dramatically higher ROS levels compared to treatment with AA and 3-PO alone in NSCLC cells and combination-induced cell death was inhibited by addition of catalase to the medium. Analyses of DNA fragmentation, poly (ADP-ribose) polymerase cleavage, annexin V-binding, and caspase activity demonstrated that AA-induced cell death is caused via the activation of apoptosis and that the combination treatments caused a synergistic induction of apoptosis. These results demonstrate the effectiveness of AA against NSCLC cells and that combinations of AA with 3-PO synergistically induce apoptosis via a ROS-dependent mechanism. These results support further evaluation of pharmacologic concentrations of AA as an adjuvant treatment for NSCLC and that combination of AA with glycolysis inhibitors may be a promising therapy for the treatment of NSCLC.
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Affiliation(s)
- Saleha B. Vuyyuri
- Owensboro Cancer Research Program, Owensboro, Kentucky, United States of America
| | - Jacob Rinkinen
- Owensboro Cancer Research Program, Owensboro, Kentucky, United States of America
| | - Erin Worden
- Owensboro Cancer Research Program, Owensboro, Kentucky, United States of America
| | - Hyekyung Shim
- Owensboro Cancer Research Program, Owensboro, Kentucky, United States of America
- Department of Pharmacology and Toxicology, James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky
| | - Sukchan Lee
- Department of Genetic Engineering, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon, Republic of Korea
| | - Keith R. Davis
- Owensboro Cancer Research Program, Owensboro, Kentucky, United States of America
- Department of Pharmacology and Toxicology, James Graham Brown Cancer Center, University of Louisville, Louisville, Kentucky
- * E-mail:
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Wu ZH, Lu MK, Hu LY, Li X. Praziquantel synergistically enhances paclitaxel efficacy to inhibit cancer cell growth. PLoS One 2012; 7:e51721. [PMID: 23251610 PMCID: PMC3520897 DOI: 10.1371/journal.pone.0051721] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 11/05/2012] [Indexed: 12/21/2022] Open
Abstract
The major challenges we are facing in cancer therapy with paclitaxel (PTX) are the drug resistance and severe side effects. Massive efforts have been made to overcome these clinical challenges by combining PTX with other drugs. In this study, we reported the first preclinical data that praziquantel (PZQ), an anti-parasite agent, could greatly enhance the anticancer efficacy of PTX in various cancer cell lines, including PTX-resistant cell lines. Based on the combination index value, we demonstrated that PZQ synergistically enhanced PTX-induced cell growth inhibition. The co-treatment of PZQ and PTX also induced significant mitotic arrest and activated the apoptotic cascade. Moreover, PZQ combined with PTX resulted in a more pronounced inhibition of tumor growth compared with either drug alone in a mouse xenograft model. We tried to investigate the possible mechanisms of this synergistic efficacy induced by PZQ and PTX, and we found that the co-treatment of the two drugs could markedly decrease expression of X-linked inhibitor of apoptosis protein (XIAP), an anti-apoptotic protein. Our data further demonstrated that down-regulation of XIAP was required for the synergistic interaction between PZQ and PTX. Together, this study suggested that the combination of PZQ and PTX may represent a novel and effective anticancer strategy for optimizing PTX therapy.
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Affiliation(s)
- Zhen Hua Wu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian, P.R. China
| | - Ming-ke Lu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian, P.R. China
| | - Long Yu Hu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian, P.R. China
| | - Xiaotong Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian, P.R. China
- * E-mail:
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53
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Masaldan S, Iyer VV. Exploration of effects of emodin in selected cancer cell lines: enhanced growth inhibition by ascorbic acid and regulation of LRP1 and AR under hypoxia-like conditions. J Appl Toxicol 2012; 34:95-104. [PMID: 23212659 DOI: 10.1002/jat.2838] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Revised: 09/22/2012] [Accepted: 10/03/2012] [Indexed: 12/25/2022]
Abstract
This study explores the link between the antiproliferative activity of emodin through the generation of reactive oxygen species (ROS) in various cancer cell lines and the expression of the androgen receptor (AR) in the prostate cancer cell lines LNCaP (androgen-sensitive) and PC-3 (androgen-refractory), as well as the pro-metastatic low-density lipoprotein receptor-related protein 1 (LRP1) in the above prostate cancer cells and the nonprostate cell lines A549 (lung), HCT-15 (colon) and MG-63 (bone) under normoxic and hypoxia-like conditions. Among all cell lines, emodin showed most growth inhibition in LNCaP, followed by A549. The mechanism of cytotoxicity of emodin was postulated to be the widely reported ROS generation, based on the observations of poor in vitro radical-scavenging activity and increased growth inhibition of emodin by ascorbic acid (AA) pre-treatment owing to the additive effects of ROS generation by emodin and pro-oxidant effects of AA. Emodin downregulated AR in LNCaP under normoxic and hypoxia-like conditions (simulated by CoCl(2)) and LRP1 under normoxia. Emodin upregulated LRP1 in other cell lines, except HCT-15, under normoxic, and even more markedly under hypoxia-like conditions. The downregulation of AR in LNCaP and upregulation of LRP1 in all cell lines, except HCT-15, under hypoxia-like conditions along with growth inhibition by emodin, suggests that emodin may be a useful therapeutic option against androgen-sensitive prostate cancer and other such LRP1-expressing cancers to attempt the targeting of the elevated LRP1 levels to allow the uptake of emodin and/or any other accompanying therapeutic agents by LRP1.
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Affiliation(s)
- Shashank Masaldan
- Centre for Bio-Separation Technology, VIT University, Vellore, 632014, Tamil Nadu, India
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Park JH, Davis KR, Lee G, Jung M, Jung Y, Park J, Yi SY, Lee MA, Lee S, Yeom CH, Kim J. Ascorbic acid alleviates toxicity of paclitaxel without interfering with the anticancer efficacy in mice. Nutr Res 2012. [PMID: 23176798 DOI: 10.1016/j.nutres.2012.09.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Paclitaxel is used extensively as a chemotherapeutic agent against a broad range of tumors but often leads to the early termination of treatment due to severe toxic side effects. In this study, we hypothesized that ascorbic acid could reduce the toxic side effects without interfering with the anticancer effect of paclitaxel. To demonstrate this, we examined the effect of the combinational treatment of ascorbic acid and paclitaxel using H1299 (a non-small cell lung cancer cell line) and BALB/c mice implanted with or without sarcoma 180 cancer cells. In H1299 cells, the anticancer effects of the combinational treatment with paclitaxel and ascorbic acid were up to 1.7-foldhigher than those of single-agent paclitaxel treatment. In addition, it was shown that the viability of the HEL299 normal cells was up to 1.6-fold higher with the combinational treatment than with paclitaxel treatment alone. In vivo mouse experiments also showed that mice co-treated with paclitaxel and ascorbic acid did not exhibit the typical side effects induced by paclitaxel, such as a reduction in the numbers of white blood cells and red blood cells and the level of hemoglobin (P < .05). The analysis of cancer-related gene expression by quantitative real-time polymerase chain reaction and immunohistochemistry revealed that the combinational treatment suppressed cancer cell multiplication. Taken together, these results suggest that combinational chemotherapy with ascorbic acid and paclitaxel not only does not block the anticancer effects of paclitaxel but also alleviates the cytotoxicity of paclitaxel in vivo and in vitro.
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Affiliation(s)
- Jin-Hee Park
- Department of Biomedical Science, College of Medicine, The Catholic University of Korea, Seoul, South Korea
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Moens B, Decanine D, Menezes SM, Khouri R, Silva-Santos G, Lopez G, Alvarez C, Talledo M, Gotuzzo E, de Almeida Kruschewsky R, Galvão-Castro B, Vandamme AM, Van Weyenbergh J. Ascorbic acid has superior ex vivo antiproliferative, cell death-inducing and immunomodulatory effects over IFN-α in HTLV-1-associated myelopathy. PLoS Negl Trop Dis 2012; 6:e1729. [PMID: 22848768 PMCID: PMC3404116 DOI: 10.1371/journal.pntd.0001729] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 05/30/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Clear therapeutic guidelines for HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) are missing due to the lack of randomized double-blind controlled clinical trials. Moderate yet similar clinical benefit has been demonstrated for IFN-α and high-dose ascorbic acid (AA) monotherapy in a large open clinical trial. However, there is a lack of in vivo and in vitro studies exploring and comparing the effects of high-dose AA and IFN-α treatment in the context of HAM/TSP. Therefore, we performed the first comparative analysis of the ex vivo and in vitro molecular and cellular mechanisms of action of IFN-α and high-dose AA in HAM/TSP. PRINCIPAL FINDINGS Through thymidine incorporation and quantification of Th1/Th2/Th17 cytokines, we demonstrate that high-dose AA displays differential and superior antiproliferative and immunomodulatory effects over IFN-α in HAM/TSP PBMCs ex vivo. In addition, high-dose AA, but not IFN-α, induced cell death in both HAM/TSP PBMCs and HTLV-1-infected T-cell lines MT-2 and MT-4. Microarray data combined with pathway analysis of MT-2 cells revealed AA-induced regulation of genes associated with cell death, including miR-155. Since miR-155 has recently been demonstrated to up-regulate IFN-γ, this microRNA might represent a novel therapeutic target in HAM/TSP, as recently demonstrated in multiple sclerosis, another neuroinflammatory disease. On the other hand, IFN-α selectively up-regulated antiviral and immune-related genes. CONCLUSIONS In comparison to IFN-α, high-dose AA treatment has superior ex vivo and in vitro cell death-inducing, antiproliferative and immunomodulatory anti-HTLV-1 effects. Differential pathway activation by both drugs opens up avenues for targeted treatment in specific patient subsets.
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Affiliation(s)
- Britta Moens
- Rega Institute for Medical Research, K. U. Leuven, Leuven, Belgium.
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Zunich SM, Valdovinos M, Douglas T, Walterhouse D, Iannaccone P, Lamm MLG. Osteoblast-secreted collagen upregulates paracrine Sonic hedgehog signaling by prostate cancer cells and enhances osteoblast differentiation. Mol Cancer 2012; 11:30. [PMID: 22559324 PMCID: PMC3398858 DOI: 10.1186/1476-4598-11-30] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Accepted: 05/04/2012] [Indexed: 12/17/2022] Open
Abstract
Background Induction of osteoblast differentiation by paracrine Sonic hedgehog (Shh) signaling may be a mechanism through which Shh-expressing prostate cancer cells initiate changes in the bone microenvironment and promote metastases. A hallmark of osteoblast differentiation is the formation of matrix whose predominant protein is type 1 collagen. We investigated the formation of a collagen matrix by osteoblasts cultured with prostate cancer cells, and its effects on interactions between prostate cancer cells and osteoblasts. Results In the presence of exogenous ascorbic acid (AA), a co-factor in collagen synthesis, mouse MC3T3 pre-osteoblasts in mixed cultures with human LNCaP prostate cancer cells or LNCaP cells modified to overexpress Shh (LNShh cells) formed collagen matrix with distinct fibril ultrastructural characteristics. AA increased the activity of alkaline phosphatase and the expression of the alkaline phosphatase gene Akp2, markers of osteoblast differentiation, in MC3T3 pre-osteoblasts cultured with LNCaP or LNShh cells. However, the AA-stimulated increase in Akp2 expression in MC3T3 pre-osteoblasts cultured with LNShh cells far exceeded the levels observed in MC3T3 cells cultured with either LNCaP cells with AA or LNShh cells without AA. Therefore, AA and Shh exert a synergistic effect on osteoblast differentiation. We determined whether the effect of AA on LNShh cell-induced osteoblast differentiation was mediated by Shh signaling. AA increased the expression of Gli1 and Ptc1, target genes of the Shh pathway, in MC3T3 pre-osteoblasts cultured with LNShh cells to at least twice their levels without AA. The ability of AA to upregulate Shh signaling and enhance alkaline phosphatase activity was blocked in MC3T3 cells that expressed a dominant negative form of the transcription factor GLI1. The AA-stimulated increase in Shh signaling and Shh-induced osteoblast differentiation was also inhibited by the specific collagen synthesis inhibitor 3,4-dehydro-L-proline. Conclusions Matrix collagen, formed by osteoblasts in the presence of AA, potentiates Shh signaling between Shh-expressing prostate cancer cells and osteoblasts. Collagen and Shh signaling exert a synergistic effect on osteoblast differentiation, a defining event in prostate carcinoma bone metastasis. Investigations into paracrine interactions among prostate cancer cells, osteoblasts, and osteoblast-synthesized matrix proteins advance our understanding of mechanisms contributing to prostate cancer bone metastasis.
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Affiliation(s)
- Samantha M Zunich
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Children's Memorial Research Center, 2300 Children's Plaza #204, Chicago, IL 60614, USA
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Attia S. Modulation of irinotecan-induced genomic DNA damage by theanine. Food Chem Toxicol 2012; 50:1749-54. [DOI: 10.1016/j.fct.2012.02.092] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Revised: 02/22/2012] [Accepted: 02/27/2012] [Indexed: 10/28/2022]
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Khoo GM, Clausen MR, Pedersen HL, Larsen E. Bioactivity and chemical composition of blackcurrant (Ribes nigrum) cultivars with and without pesticide treatment. Food Chem 2011; 132:1214-1220. [PMID: 29243603 DOI: 10.1016/j.foodchem.2011.11.087] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 11/10/2011] [Accepted: 11/16/2011] [Indexed: 12/30/2022]
Abstract
Eleven blackcurrant cultivars grown with pesticide (PT) and without pesticide treatment (PF) were evaluated to compare the differences in plant growth and physical condition, total anthocyanin content, ascorbic acid content, total antioxidant capacity, effect on prostaglandin E2 (PGE2) production and anticancer cell proliferation activities. Results showed that the yield and growth of PT blackcurrants were higher. However, PF blackcurrants contained a higher amount of ascorbic acid, and displayed an increased inhibition against cancer cells compared to PT blackcurrants, indicating that PF blackcurrants have an increased potential to deliver health-promoting benefit for consumers. Significant differences were observed between blackcurrant cultivars in relation to plant growth and physical condition, total anthocyanin content and PGE2 assay, highlighting the importance of cultivar selection.
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Affiliation(s)
- Gaik Ming Khoo
- Department of Food Science, Aarhus University, Kirstinebjergvej 10, DK-5792 Aarslev, Denmark
| | - Morten Rahr Clausen
- Department of Food Science, Aarhus University, Kirstinebjergvej 10, DK-5792 Aarslev, Denmark
| | - Hanne Lindhard Pedersen
- Department of Horticulture, Aarhus University, Kirstinebjergvej 10, DK-5792 Aarslev, Denmark
| | - Erik Larsen
- Department of Food Science, Aarhus University, Kirstinebjergvej 10, DK-5792 Aarslev, Denmark.
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Chen P, Stone J, Sullivan G, Drisko JA, Chen Q. Anti-cancer effect of pharmacologic ascorbate and its interaction with supplementary parenteral glutathione in preclinical cancer models. Free Radic Biol Med 2011; 51:681-7. [PMID: 21672627 DOI: 10.1016/j.freeradbiomed.2011.05.031] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 05/20/2011] [Accepted: 05/23/2011] [Indexed: 11/22/2022]
Abstract
Two popular complementary, alternative, and integrative medicine therapies, high-dose intravenous ascorbic acid (AA) and intravenous glutathione (GSH), are often coadministered to cancer patients with unclear efficacy and drug-drug interaction. In this study we provide the first survey evidence for clinical use of iv GSH with iv AA. To address questions of efficacy and drug-drug interaction, we tested 10 cancer cell lines with AA, GSH, and their combination. The results showed that pharmacologic AA induced cytotoxicity in all tested cancer cells, with IC(50) less than 4 mM, a concentration easily achievable in humans. GSH reduced cytotoxicity by 10-95% by attenuating AA-induced H(2)O(2) production. Treatment in mouse pancreatic cancer xenografts showed that intraperitoneal AA at 4 g/kg daily reduced tumor volume by 42%. Addition of intraperitoneal GSH inhibited the AA-induced tumor volume reduction. Although all treatments (AA, GSH, and AA+GSH) improved survival rate, AA+GSH inhibited the cytotoxic effect of AA alone and failed to provide further survival benefit. These data confirm the pro-oxidative anti-cancer mechanism of pharmacologic AA and suggest that AA and GSH administered together provide no additional benefit compared with AA alone. There is an antagonism between ascorbate and glutathione in treating cancer, and therefore iv AA and iv GSH should not be coadministered to cancer patients on the same day.
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Affiliation(s)
- Ping Chen
- Program in Integrative Medicine, University of Kansas Medical Center, Kansas City, KS 66160, USA
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60
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Espey MG, Chen P, Chalmers B, Drisko J, Sun AY, Levine M, Chen Q. Pharmacologic ascorbate synergizes with gemcitabine in preclinical models of pancreatic cancer. Free Radic Biol Med 2011; 50:1610-9. [PMID: 21402145 PMCID: PMC3482496 DOI: 10.1016/j.freeradbiomed.2011.03.007] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 03/01/2011] [Accepted: 03/04/2011] [Indexed: 12/19/2022]
Abstract
Conventional treatment approaches have had little impact on the course of pancreatic cancer, which has the highest fatality rate among cancers. Gemcitabine, the primary therapeutic agent for pancreatic carcinoma, produces minimal survival benefit as a single agent. Therefore, numerous efforts have focused on gemcitabine combination treatments. Using a ratio design, this study established that combining pharmacologically achievable concentrations of ascorbate with gemcitabine resulted in a synergistic cytotoxic response in eight pancreatic tumor cell lines. Sensitization was evident regardless of inherent gemcitabine resistance and epithelial-mesenchymal phenotype. Our analysis suggested that the promiscuous oxidative actions of H(2)O(2) derived from pharmacologic ascorbate can culminate in synergism independent of the cancer cell's underlying phenotype and resistance to gemcitabine monotherapy. Gemcitabine-ascorbate combinations administered to mice bearing pancreatic tumor xenografts consistently enhanced inhibition of growth compared to gemcitabine alone, produced 50% growth inhibition in a tumor type not responsive to gemcitabine, and demonstrated a gemcitabine dose-sparing effect. These data support the testing of pharmacologic ascorbate in adjunctive treatments for cancers prone to high failure rates with conventional therapeutic regimens, such as pancreatic cancer.
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Affiliation(s)
- Michael Graham Espey
- Molecular and Clinical Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ping Chen
- Program in Integrative Medicine, Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA
- Department of Genetic and Molecular Biology, Xi'an Jiaotong University School of Medicine, Xi'an 710061, China
| | - Brian Chalmers
- Program in Integrative Medicine, Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Jeanne Drisko
- Program in Integrative Medicine, Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Andrew Y. Sun
- Molecular and Clinical Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mark Levine
- Molecular and Clinical Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Qi Chen
- Program in Integrative Medicine, Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA
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In vitro screening of synergistic ascorbate-drug combinations for the treatment of malignant mesothelioma. Toxicol In Vitro 2011; 25:1568-74. [PMID: 21645609 DOI: 10.1016/j.tiv.2011.05.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 05/20/2011] [Accepted: 05/23/2011] [Indexed: 02/07/2023]
Abstract
Malignant mesothelioma (MMe) is a lethal tumor arising from the mesothelium of serous cavities as a result of exposure to asbestos. Current clinical standards consist of combined treatments, but an effective therapy has not been established yet and there is an urgent need for new curative approaches. Ascorbate is a nutrient that is also known as a remedy in the treatment of cancer. In the present study, we have tested the cytotoxicity of ascorbate to MMe cells in combination with drugs used in MMe therapy, such as cisplatin, etoposide, gemcitabine, imatinib, paclitaxel, and raltitrexed, as well as with promising antitumor compounds like taurolidine, α-tocopherol succinate, and epigallocatechin-3-gallate (EGCG). Dose-response curves obtained for each compound by applying the neutral red uptake (NRU) assay to MMe cells growing in vitro, allowed to obtain IC50 values for each compound used singularly. Thereafter, NRU data obtained from each ascorbate/drug combination were analyzed through Tallarida's isobolograms at the IC50 level (Tallarida, 2000), revealing synergistic interactions for ascorbate/gemcitabine and ascorbate/EGCG. These results were further confirmed through comparisons between theoretical additivity IC50 and observed IC50 from fixed-ratio dose-response curves, and over a broad range of IC levels, by using Chou and Talalay's combination index (Chou and Talalay, 1984). Synergistic interactions were also shown by examining apoptosis and necrosis rates, using the caspase 3 and lactic dehydrogenase assays, respectively. Hence, data indicate that ascorbate/gemcitabine and ascorbate/EGCG affect synergistically the viability of MMe cells and suggest their possible use in the clinical treatment of this problematic cancer.
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Batinić-Haberle I, Rajić Z, Benov L. A combination of two antioxidants (an SOD mimic and ascorbate) produces a pro-oxidative effect forcing Escherichia coli to adapt via induction of oxyR regulon. Anticancer Agents Med Chem 2011; 11:329-40. [PMID: 21355843 PMCID: PMC3652549 DOI: 10.2174/187152011795677562] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 03/10/2011] [Indexed: 11/22/2022]
Abstract
Cationic Mn(III) N-alkylpyridyl (MnTalkyl-2(or 3)-PyP(5+)) and N, N'-dialkylimidazolylporphyrins (MnTDalkyl-2-ImP(5+)) have been regarded as the most powerful SOD mimics/peroxynitrite scavengers - i. e. antioxidants. The ethyl-, MnTE-2-PyP(5+) (AEOL10113), and hexylpyridyl-, MnTnHex-2-PyP(5+) and diethylimidazolylporphyrin, MnTDE-2-ImP(5+) (AEOL10150) have been mostly studied in vitro and in vivo. Given the in vivo abundance of cellular reductants, MnPs can couple with them in removing superoxide. Thus, they could be readily reduced from Mn(III)P to Mn(II)P with ascorbate and glutathione, and in a subsequent step reduce either O(2)(.-) (while acting as superoxide reductase) or oxygen (while exerting pro-oxidative action). Moreover, MnPs can catalyze ascorbate oxidation and in turn hydrogen peroxide production. The in vivo type of MnP action (anti- or pro-oxidative) will depend upon the cellular levels of reactive species, endogenous antioxidants, availability of oxygen, ratio of O(2)(.-)- to peroxide-removing systems, redox ability of MnPs and their cellular localization/bioavailibility. To exemplify the switch from an anti- to pro-oxidative action we have explored a very simple and straightforward system - the superoxide-specific aerobic growth of SOD-deficient E. coli. In such a system, cationic MnPs, ortho and meta MnTE-2-(or 3)-PyP(5+) act as powerful SOD mimics. Yet, in the presence of exogenous ascorbate, the SOD mimics catalyze the H(2)O(2) production, causing oxidative damage to both wild and SOD-deficient strains and inhibiting their growth. Catalase added to the medium reversed the effect indicating that H(2)O(2) is a major damaging/signaling species involved in cell growth suppression. The experiments with oxyR- and soxRS-deficient E. coli were conducted to show that E. coli responds to increased oxidative stress exerted by MnP/ascorbate system by induction of oxyR regulon and thus upregulation of antioxidative defenses such as catalases and peroxidases. As anticipated, when catalase was added into medium to remove H(2)O(2), E. coli did not respond with upregulation of its own antioxidant systems.
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Affiliation(s)
- Ines Batinić-Haberle
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
| | - Zrinka Rajić
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ludmil Benov
- Department of Biochemistry, Faculty of Medicine, Kuwait School of Medicine, Kuwait
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Levine M, Padayatty SJ, Espey MG. Vitamin C: a concentration-function approach yields pharmacology and therapeutic discoveries. Adv Nutr 2011; 2:78-88. [PMID: 22332036 PMCID: PMC3065766 DOI: 10.3945/an.110.000109] [Citation(s) in RCA: 205] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A concentration-function approach to vitamin C (ascorbate) has yielded new physiology and pharmacology discoveries. To determine the range of vitamin C concentrations possible in humans, pharmacokinetics studies were conducted. They showed that when vitamin C is ingested by mouth, plasma and tissue concentrations are tightly controlled by at least 3 mechanisms in healthy humans: absorption, tissue accumulation, and renal reabsorption. A 4th mechanism, rate of utilization, may be important in disease. With ingested amounts found in foods, vitamin C plasma concentrations do not exceed 100 μmol/L. Even with supplementation approaching maximally tolerated doses, ascorbate plasma concentrations are always <250 μmol/L and frequently <150 μmol/L. By contrast, when ascorbate is i.v. injected, tight control is bypassed until excess ascorbate is eliminated by glomerular filtration and renal excretion. With i.v. infusion, pharmacologic ascorbate concentrations of 25-30 mmol/L are safely achieved. Pharmacologic ascorbate can act as a pro-drug for hydrogen peroxide (H(2)O(2)) formation, which can lead to extracellular fluid at concentrations as high as 200 μmol/L. Pharmacologic ascorbate can elicit cytotoxicity toward cancer cells and slow the growth of tumors in experimental murine models. The effects of pharmacologic ascorbate should be further studied in diseases, such as cancer and infections, which may respond to generation of reactive oxygen species via H(2)O(2).
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Affiliation(s)
- Mark Levine
- Molecular and Clinical Nutrition Section, Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1372, USA.
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Ichim TE, Minev B, Braciak T, Luna B, Hunninghake R, Mikirova NA, Jackson JA, Gonzalez MJ, Miranda-Massari JR, Alexandrescu DT, Dasanu CA, Bogin V, Ancans J, Stevens RB, Markosian B, Koropatnick J, Chen CS, Riordan NH. Intravenous ascorbic acid to prevent and treat cancer-associated sepsis? J Transl Med 2011; 9:25. [PMID: 21375761 PMCID: PMC3061919 DOI: 10.1186/1479-5876-9-25] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 03/04/2011] [Indexed: 02/07/2023] Open
Abstract
The history of ascorbic acid (AA) and cancer has been marked with controversy. Clinical studies evaluating AA in cancer outcome continue to the present day. However, the wealth of data suggesting that AA may be highly beneficial in addressing cancer-associated inflammation, particularly progression to systemic inflammatory response syndrome (SIRS) and multi organ failure (MOF), has been largely overlooked. Patients with advanced cancer are generally deficient in AA. Once these patients develop septic symptoms, a further decrease in ascorbic acid levels occurs. Given the known role of ascorbate in: a) maintaining endothelial and suppression of inflammatory markers; b) protection from sepsis in animal models; and c) direct antineoplastic effects, we propose the use of ascorbate as an adjuvant to existing modalities in the treatment and prevention of cancer-associated sepsis.
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Affiliation(s)
- Thomas E Ichim
- Department of Orthomolecular Studies, Riordan Clinic, 3100 N Hillside, Wichita, Kansas, 67210, USA
- Department of Regenerative Medicine, Medistem Inc, 9255 Towne Centre Drive, San Diego, California, 92121. USA
| | - Boris Minev
- Department of Medicine, Moores Cancer Center, University of California San Diego, 3855 Health Sciences Dr, San Diego, California, 92121, USA
| | - Todd Braciak
- Department of Regenerative Medicine, Medistem Inc, 9255 Towne Centre Drive, San Diego, California, 92121. USA
- Department of Immunology, Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, La Jolla, California,92121, USA
| | - Brandon Luna
- Department of Regenerative Medicine, Medistem Inc, 9255 Towne Centre Drive, San Diego, California, 92121. USA
| | - Ron Hunninghake
- Department of Orthomolecular Studies, Riordan Clinic, 3100 N Hillside, Wichita, Kansas, 67210, USA
| | - Nina A Mikirova
- Department of Orthomolecular Studies, Riordan Clinic, 3100 N Hillside, Wichita, Kansas, 67210, USA
| | - James A Jackson
- Department of Orthomolecular Studies, Riordan Clinic, 3100 N Hillside, Wichita, Kansas, 67210, USA
| | - Michael J Gonzalez
- Department of Human Development, Nutrition Program, University of Puerto Rico, Medical Sciences Campus, San Juan, 00936-5067, PR
| | - Jorge R Miranda-Massari
- Department of Pharmacy Practice, University of Puerto Rico, Medical Sciences Campus, School of Pharmacy, San Juan, 00936-5067, PR
| | - Doru T Alexandrescu
- Department of Experimental Studies, Georgetown Dermatology, 3301 New Mexico Ave, Washington DC, 20018, USA
| | - Constantin A Dasanu
- Department of Hematology and Oncology, University of Connecticut, 115 North Eagleville Road, Hartford, Connecticut, 06269, USA
| | - Vladimir Bogin
- Department of Regenerative Medicine, Medistem Inc, 9255 Towne Centre Drive, San Diego, California, 92121. USA
| | - Janis Ancans
- Department of Surgery, University of Latvia, 19 Raina Blvd, Riga, LV 1586, Latvia
| | - R Brian Stevens
- Department of Surgery, Microbiology, and Pathology, University of Nebraska Medical Center, 42nd and Emile, Omaha, Nebraska, 86198, USA
| | - Boris Markosian
- Department of Regenerative Medicine, Medistem Inc, 9255 Towne Centre Drive, San Diego, California, 92121. USA
| | - James Koropatnick
- Department of Microbiology and Immunology, and Department of Oncology, Lawson Health Research Institute and The University of Western Ontario, 1151 Richmond Street, London, Ontario, N2G 3M5, Canada
| | - Chien-Shing Chen
- School of Medicine, Division of Hematology and Oncology, Loma Linda University,24851 Circle Dr, Loma Linda, California, 92354, USA
| | - Neil H Riordan
- Department of Orthomolecular Studies, Riordan Clinic, 3100 N Hillside, Wichita, Kansas, 67210, USA
- Department of Regenerative Medicine, Medistem Inc, 9255 Towne Centre Drive, San Diego, California, 92121. USA
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