1
Proc Natl Acad Sci U S A. 2005 Sep 20;102(38):13604-9. doi: 10.1073/pnas.0506390102. Epub 2005 Sep 12.
Qi Chen 1 , Michael Graham Espey, Murali C Krishna, James B Mitchell, Christopher P Corpe, Garry R Buettner, Emily Shacter, Mark Levine
Free PMC article
Abstract
Human pharmacokinetics data indicate that i.v. ascorbic acid (ascorbate) in pharmacologic concentrations could have an unanticipated role in cancer treatment. Our goals here were to test whether ascorbate killed cancer cells selectively, and if so, to determine mechanisms, using clinically relevant conditions. Cell death in 10 cancer and 4 normal cell types was measured by using 1-h exposures. Normal cells were unaffected by 20 mM ascorbate, whereas 5 cancer lines had EC(50) values of <4 mM, a concentration easily achievable i.v. Human lymphoma cells were studied in detail because of their sensitivity to ascorbate (EC(50) of 0.5 mM) and suitability for addressing mechanisms. Extracellular but not intracellular ascorbate mediated cell death, which occurred by apoptosis and pyknosis/necrosis. Cell death was independent of metal chelators and absolutely dependent on H(2)O(2) formation. Cell death from H(2)O(2) added to cells was identical to that found when H(2)O(2) was generated by ascorbate treatment. H(2)O(2) generation was dependent on ascorbate concentration, incubation time, and the presence of 0.5-10% serum, and displayed a linear relationship with ascorbate radical formation. Although ascorbate addition to medium generated H(2)O(2), ascorbate addition to blood generated no detectable H(2)O(2) and only trace detectable ascorbate radical. Taken together, these data indicate that ascorbate at concentrations achieved onlyby i.v. administration may be a pro-drug for formation of H(2)O(2), and that blood can be a delivery system of the pro-drug to tissues. These findings give plausibility to i.v. ascorbic acid in cancer treatment, and have unexpected implications for treatment of infections where H(2)O(2) may be beneficial.
2
Clinical Trial
Sci Transl Med. 2014 Feb 5;6(222):222ra18. doi: 10.1126/scitranslmed.3007154.
Yan Ma 1 , Julia Chapman, Mark Levine, Kishore Polireddy, Jeanne Drisko, Qi Chen
Free article
Abstract
Ascorbate (vitamin C) was an early, unorthodox therapy for cancer, with an outstanding safety profile and anecdotal clinical benefit. Because oral ascorbate was ineffective in two cancer clinical trials, ascorbate was abandoned by conventional oncology but continued to be used in complementary and alternative medicine. Recent studies provide rationale for reexamining ascorbate treatment. Because of marked pharmacokinetic differences, intravenous, but not oral, ascorbate produces millimolar concentrations both in blood and in tissues, killing cancer cells without harming normal tissues. In the interstitial fluid surrounding tumor cells, millimolar concentrations of ascorbate exert local pro-oxidant effects by mediating hydrogen peroxide (H(2)O(2)) formation, which kills cancer cells. We investigated downstream mechanisms of ascorbate-induced cell death. Data show that millimolar ascorbate, acting as a pro-oxidant, induced DNA damage and depleted cellular adenosine triphosphate (ATP), activated the ataxia telangiectasia mutated (ATM)/adenosine monophosphate-activated protein kinase (AMPK) pathway, and resulted in mammalian target of rapamycin (mTOR) inhibition and death in ovarian cancer cells. The combination of parenteral ascorbate with the conventional chemotherapeutic agents carboplatin and paclitaxel synergistically inhibited ovarian cancerin mouse models and reduced chemotherapy-associated toxicity in patients with ovarian cancer. On the basis of its potential benefit and minimal toxicity, examination of intravenous ascorbate in combination with standard chemotherapy is justified in larger clinical trials.
3
Leuk Lymphoma. 2013 May;54(5):1069-78. doi: 10.3109/10428194.2012.739686. Epub 2012 Nov 15.
Amber N Shatzer 1 , Michael Graham Espey, Mayra Chavez, Hongbin Tu, Mark Levine, Jeffrey I Cohen
Affiliations expand
- PMID: 23067008 PMCID: PMC4055524 DOI:10.3109/10428194.2012.739686
Free PMC article
Abstract
Ascorbic acid has been shown to kill various cancer cell lines at pharmacologic concentrations.We found that Epstein-Barr virus (EBV)-positive Burkitt lymphoma (BL) cells were more susceptible to ascorbic acid-induced cell killing than EBV-negative BL cells or EBV-transformed lymphoblastoid cells (LCLs). Ascorbic acid did not induce apoptosis in any of the tested cells but did induce the production of reactive oxygen species and cell death. Previously, we showed that bortezomib, a proteasome inhibitor, induces cell death in LCLs and EBV-positive BL cells. We found that ascorbic acid is strongly antagonistic for bortezomib-induced cell death in LCLs and EBV-positive BL cells. Finally, ascorbic acid did not prolong survival of severe combined immunodefiency mice inoculated with LCLs either intraperitoneally or subcutaneously. Thus, while ascorbic acid was highly effective at killing EBV-positive BL cells and LCLs in vitro, it antagonized cell killing by bortezomib and was ineffective in an animal model.
Case Reports
Anticancer Drugs. 2018 Apr;29(4):373-379. doi: 10.1097/CAD.0000000000000603.
Treatment of pancreatic cancer with intravenous vitamin C: a case report
Jeanne A Drisko 1 , Oscar K Serrano 2 , Lisa R Spruce 3 , Qi Chen 4 , Mark Levine 5
Free PMC article
Abstract
Pancreatic ductal adenocarcinoma (PDA) has a dismal prognosis and is often discovered at an advanced stage with few therapeutic options. Current conventional regimens for PDA are associated with significant morbidity, decreased quality of life, and a considerable financial burden. As a result, some patients turn to integrative medicine therapies as an alternate option after a diagnosis of PDA. Intravenous pharmacologic ascorbic acid (PAA) is one such treatment. The use of PAA has been passionately debated for many years, but more recent rigorous scientific research has shown that there are significant blood concentration differences when ascorbic acid is given parenterally when compared to oral dosing. This pharmacologic difference appears to be critical for its role in oncology. Here, we report the use of PAA in a patient with poorly differentiated stage IV PDA as an exclusive chemotherapeutic regimen. The patient survived nearly 4 years after diagnosis, with PAA as his sole treatment, and he achieved objective regression of his disease. He died from sepsis and organ failure from a bowel perforation event. This case illustrates the possibility of PAA to effectively control tumor progression and serve as an adjunct to standard of care PDA chemotherapy regimens. Our patient’s experience with PAA should be taken into consideration, along with previous research in cell, animal, and clinical experiments to design future treatment trials.
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Clinical Trial
Proc Natl Acad Sci U S A Epub 2008 Aug 4.
Qi Chen 1 , Michael Graham Espey, Andrew Y Sun, Chaya Pooput, Kenneth L Kirk, Murali C Krishna, Deena Beneda Khosh, Jeanne Drisko, Mark Levine
Free PMC article
Abstract
Ascorbic acid is an essential nutrient commonly regarded as an antioxidant. In this study, we showed that ascorbate at pharmacologic concentrations was a prooxidant, generating hydrogen-peroxide-dependent cytotoxicity toward a variety of cancer cells in vitro without adversely affecting normal cells. To test this action in vivo, normal oral tight control was bypassed by parenteral ascorbate administration. Real-time microdialysis sampling in mice bearing glioblastoma xenografts showed that a single pharmacologic dose of ascorbate produced sustained ascorbate radical and hydrogen peroxide formation selectively within interstitial fluids of tumors but not in blood. Moreover, a regimen of daily pharmacologic ascorbate treatment significantly decreased growth rates of ovarian (P < 0.005), pancreatic (P < 0.05), and glioblastoma (P < 0.001) tumors established in mice. Similar pharmacologic concentrations were readily achieved in humans given ascorbate intravenously. These data suggest that ascorbate as a prodrug may have benefits in cancers with poor prognosis and limited therapeutic options.
Conflict of interest statement
The authors declare no conflict of interest.
7
In Vivo. May-Jun 2010;24(3):249-55.
Harvey B Pollard 1 , Mark A Levine, Ofer Eidelman, Morris Pollard
Abstract
Aim: The aim of this study was to test for the influence of ascorbic acid on tumorigenicity and metastases of implanted PAIII prostate cancer adenocarcinoma cells in syngeneic LW rats.
Materials and methods: Hormone-refractory prostate cancer PAIII cells were implanted subcutaneously into immunologically intact, Lobund-Wistar (LW) rats. Intraperitoneal pharmacological doses of ascorbic acid were administered each day for the ensuing 30 days. On the 40th day, animals were sacrificed. Local tumor weights were measured, and metastases were counted.
Results: At the end of the 40 day experimental period, the primary tumors were found to be significantly reduced in weight (p=0.026). In addition, sub-pleural lung metastases were even more profoundly reduced in number and size (p=0.009). Grossly enlarged ipsilateral lymph node metastases declined from 7 of 15 rats to 1 of 15 rats.
Conclusion: Pharmacological doses of ascorbic acid suppress tumor growth and metastases in hormone-refractory prostate cancer.
Clinical Trial
Proc Natl Acad Sci U S A. 2008 Aug 12;105(32):11105-9. doi: 10.1073/pnas.0804226105. Epub 2008 Aug 4.
Qi Chen 1 , Michael Graham Espey, Andrew Y Sun, Chaya Pooput, Kenneth L Kirk, Murali C Krishna, Deena Beneda Khosh, Jeanne Drisko, Mark Levine
Abstract
Ascorbic acid is an essential nutrient commonly regarded as an antioxidant. In this study, we showed that ascorbate at pharmacologic concentrations was a prooxidant, generating hydrogen-peroxide-dependent cytotoxicity toward a variety of cancer cells in vitro without adversely affecting normal cells. To test this action in vivo, normal oral tight control was bypassed by parenteral ascorbate administration. Real-time microdialysis sampling in mice bearing glioblastoma xenografts showed that a single pharmacologic dose of ascorbate produced sustained ascorbate radical and hydrogen peroxide formation selectively within interstitial fluids of tumors but not in blood. Moreover, a regimen of daily pharmacologic ascorbate treatment significantly decreased growth rates of ovarian (P < 0.005), pancreatic (P < 0.05), and glioblastoma (P < 0.001) tumors established in mice. Similar pharmacologic concentrations were readily achieved in humans given ascorbate intravenously. These data suggest that ascorbate as a prodrug may have benefits in cancers with poor prognosis and limited therapeutic options.
Conflict of interest statement
The authors declare no conflict of interest.