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Lu J, Liu H, Wang B, Chen C, Bai F, Su X, Duan P. Niraparib plays synergistic antitumor effects with NRT in a mouse ovarian cancer model with HRP. Transl Oncol 2024; 49:102094. [PMID: 39163760 PMCID: PMC11380394 DOI: 10.1016/j.tranon.2024.102094] [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: 04/24/2024] [Revised: 07/22/2024] [Accepted: 08/11/2024] [Indexed: 08/22/2024] Open
Abstract
OBJECTIVE PARPi offers less clinical benefit for HRP patients compared to HRD patients. PARPi has an immunomodulatory function. NRT therapy targets tumor neoantigens without off-target immune toxicity. We explored the synergy between Niraparib and NRT in enhancing antitumor activity in an HRP ovarian cancer mouse model. METHODS In the C57BL/6 mouse ID8 ovarian cancer model, the effect of Niraparib on reshaping TIME was evaluated by immune cell infiltration analysis of transcriptomic data. The antitumor effects of Niraparib, NRT, and their combined use were systematically evaluated. To corroborate alterations in TILs, TAMs, and chemokine profiles within the TIME, we employed immunofluorescence imaging and transcriptome sequencing analysis. RESULTS Niraparib increased the M1-TAMs and activated CD8+ T cells in tumor tissues of C57BL/6 mice with ID8 ovarian cancer. GSEA showed that gene set associated with immature DC and INFα, cytokines and chemokines were significantly enriched in immune feature, KEGG and GO gene sets, meanwhile CCL5, CXCL9 and CXCL10 play dominant roles together. In the animal trials, combined group had a tumor growth delay compared with Niraparib group (P < 0.01) and control group (P < 0.001), and longer survival compared with the single agent group (P<0.01) . CONCLUSIONS Niraparib could exert immune-reshaping effects, then acts synergistic antitumor effects with NRT in HRP ovarian cancer model. Our findings provide new ideas and rationale for combined immunotherapy in HRP ovarian cancer.
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Affiliation(s)
- Jiefang Lu
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, China; Department of Obstetrics and Gynecology, Lishui People's Hospital, China; Department of Obstetrics and Gynecology, The First Affiliated Hospital of Lishui College, China
| | - Haiying Liu
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, China; Department of Obstetrics and Gynecology, Lishui People's Hospital, China
| | - Binming Wang
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, China
| | - Chengcheng Chen
- Department of Gastrointestinal Surgery, The Second Afliated Hospital of Wenzhou Medical University, China
| | - Fumao Bai
- Department of clinical laboratory, The First Affiliated Hospital of Wenzhou Medical University, China
| | - Xiaoping Su
- School of Basic Medicine, Wenzhou Medical University, China; Department of Gastrointestinal Surgery, The Second Afliated Hospital of Wenzhou Medical University, China.
| | - Ping Duan
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital of Wenzhou Medical University, China; Oncology Discipline Group, The Second Affiliated Hospital of Wenzhou Medical University, China.
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Quiñonero F, Parra-Torrejón B, Ramírez-Rodríguez GB, Garcés V, Delgado-López JM, Jiménez-Luna C, Perazzoli G, Melguizo C, Prados J, Ortíz R. Combining Olaparib and Ascorbic Acid on Nanoparticles to Enhance the Drug Toxic Effects in Pancreatic Cancer. Int J Nanomedicine 2023; 18:5075-5093. [PMID: 37701822 PMCID: PMC10493099 DOI: 10.2147/ijn.s415631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 06/29/2023] [Indexed: 09/14/2023] Open
Abstract
Introduction Pancreatic cancer (PC) shows a very poor response to current treatments. Development of drug resistance is one of the causes of the therapy failure, being PARP1 (poly ADP-ribose polymerase 1) a relevant protein in the resistance mechanism. In this work, we have functionalized calcium phosphate-based nanoparticles (NPs) with Olaparib (OLA, a PARP-1 inhibitor) in combination with ascorbic acid (AA), a pro-oxidative agent, to enhance their individual effects. Methods Amorphous Calcium Phosphate (ACP) NPs were synthesized through a biomimetic approach and then functionalized with OLA and AA (NP-ACP-OLA-AA). After evaluation of the loading capacity and release kinetic, cytotoxicity, cell migration, immunofluorescence, and gene expression assays were performed using pancreatic tumor cell lines. In vivo studies were carried out on tumors derived from the PANC-1 line in NOD SCID gamma (NSG) mice. Results NP-ACP-OLA-AA was loaded with 13%wt of OLA (75% loading efficiency) and 1% of AA, respectively. The resulting dual nanosystem exhibited a gradual release of OLA and AA, being the latter protected from degradation in solution. This ensured the simultaneous availability of OLA and AA for a longer period, at least, during the entire time of in vitro cell experiments (72 hours). In vitro studies indicated that NP-ACP-OLA-AA showed the best cytotoxic effect outperforming that of the free OLA and a higher genotoxicity and apoptosis-mediated cytotoxic effect in human pancreatic ductal adenocarcinoma cell line. Interestingly, the in vivo assays using immunosuppressed mice with PANC-1-induced tumors revealed that NP-ACP-OLA-AA produced a higher tumor volume reduction (59.1%) compared to free OLA (28.3%) and increased the mice survival. Conclusion Calcium phosphate NPs, a highly biocompatible and biodegradable system, were an ideal vector for the OLA and AA co-treatment in PC, inducing significant therapeutic benefits relative to free OLA, including cytotoxicity, induction of apoptosis, inhibition of cell migration, tumor growth, and survival.
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Affiliation(s)
- Francisco Quiñonero
- Institute of Biopathology and Regenerative Medicine (IBIMER), Center of Biomedical Research (CIBM), University of Granada, Granada, 18100, Spain
- Instituto de Investigación Biosanitaria de Granada (ibs.GRANADA), Granada, 18014, Spain
| | - Belén Parra-Torrejón
- Department of Inorganic Chemistry, Faculty of Science, University of Granada, Granada, 18071, Spain
| | | | - Victor Garcés
- Department of Inorganic Chemistry, Faculty of Science, University of Granada, Granada, 18071, Spain
| | - José M Delgado-López
- Department of Inorganic Chemistry, Faculty of Science, University of Granada, Granada, 18071, Spain
| | - Cristina Jiménez-Luna
- Institute of Biopathology and Regenerative Medicine (IBIMER), Center of Biomedical Research (CIBM), University of Granada, Granada, 18100, Spain
- Instituto de Investigación Biosanitaria de Granada (ibs.GRANADA), Granada, 18014, Spain
- Department of Anatomy and Embryology, Faculty of Medicine, University of Granada, Granada, 18071, Spain
| | - Gloria Perazzoli
- Institute of Biopathology and Regenerative Medicine (IBIMER), Center of Biomedical Research (CIBM), University of Granada, Granada, 18100, Spain
- Instituto de Investigación Biosanitaria de Granada (ibs.GRANADA), Granada, 18014, Spain
- Department of Anatomy and Embryology, Faculty of Medicine, University of Granada, Granada, 18071, Spain
| | - Consolación Melguizo
- Institute of Biopathology and Regenerative Medicine (IBIMER), Center of Biomedical Research (CIBM), University of Granada, Granada, 18100, Spain
- Instituto de Investigación Biosanitaria de Granada (ibs.GRANADA), Granada, 18014, Spain
- Department of Anatomy and Embryology, Faculty of Medicine, University of Granada, Granada, 18071, Spain
| | - Jose Prados
- Institute of Biopathology and Regenerative Medicine (IBIMER), Center of Biomedical Research (CIBM), University of Granada, Granada, 18100, Spain
- Instituto de Investigación Biosanitaria de Granada (ibs.GRANADA), Granada, 18014, Spain
- Department of Anatomy and Embryology, Faculty of Medicine, University of Granada, Granada, 18071, Spain
| | - Raul Ortíz
- Institute of Biopathology and Regenerative Medicine (IBIMER), Center of Biomedical Research (CIBM), University of Granada, Granada, 18100, Spain
- Instituto de Investigación Biosanitaria de Granada (ibs.GRANADA), Granada, 18014, Spain
- Department of Anatomy and Embryology, Faculty of Medicine, University of Granada, Granada, 18071, Spain
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O’Leary BR, Ruppenkamp EK, Steers GJ, Du J, Carroll RS, Wagner BA, Buettner GR, Cullen JJ. Pharmacological Ascorbate Enhances Chemotherapies in Pancreatic Ductal Adenocarcinoma. Pancreas 2022; 51:684-693. [PMID: 36099493 PMCID: PMC9547864 DOI: 10.1097/mpa.0000000000002086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVES Pharmacological ascorbate (P-AscH - , high-dose, intravenous vitamin C) has shown promise as an adjuvant therapy for pancreatic ductal adenocarcinoma (PDAC) treatment. The objective of this study was to determine the effects of P-AscH - when combined with PDAC chemotherapies. METHODS Clonogenic survival, combination indices, and DNA damage were determined in human PDAC cell lines treated with P-AscH - in combination with 5-fluorouracil, paclitaxel, or FOLFIRINOX (combination of leucovorin, 5-fluorouracil, irinotecan, oxaliplatin). Tumor volume changes, overall survival, blood analysis, and plasma ascorbate concentration were determined in vivo in mice treated with P-AscH - with or without FOLFIRINOX. RESULTS P-AscH - combined with 5-fluorouracil, paclitaxel, or FOLFIRINOX significantly reduced clonogenic survival in vitro. The DNA damage, measured by γH2AX protein expression, was increased after treatment with P-AscH - , FOLFIRINOX, and their combination. In vivo, tumor growth rate was significantly reduced by P-AscH - , FOLFIRINOX, and their combination. Overall survival was significantly increased by the combination of P-AscH - and FOLFIRINOX. Treatment with P-AscH - increased red blood cell and hemoglobin values but had no effect on white blood cell counts. Plasma ascorbate concentrations were significantly elevated in mice treated with P-AscH - with or without FOLFIRINOX. CONCLUSIONS The addition of P-AscH - to standard of care chemotherapy has the potential to be an effective adjuvant for PDAC treatment.
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Affiliation(s)
- Brianne R. O’Leary
- Department of Surgery, The University of Iowa Carver College of Medicine, Iowa City, IA
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, The University of Iowa Carver College of Medicine, Iowa City, IA
| | - Elena K. Ruppenkamp
- Department of Surgery, The University of Iowa Carver College of Medicine, Iowa City, IA
| | - Garett J. Steers
- Department of Surgery, The University of Iowa Carver College of Medicine, Iowa City, IA
| | - Juan Du
- Department of Surgery, The University of Iowa Carver College of Medicine, Iowa City, IA
| | - Rory S. Carroll
- Department of Surgery, The University of Iowa Carver College of Medicine, Iowa City, IA
| | - Brett A. Wagner
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, The University of Iowa Carver College of Medicine, Iowa City, IA
| | - Garry R. Buettner
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, The University of Iowa Carver College of Medicine, Iowa City, IA
| | - Joseph J. Cullen
- Department of Surgery, The University of Iowa Carver College of Medicine, Iowa City, IA
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, The University of Iowa Carver College of Medicine, Iowa City, IA
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Chen P, Reed G, Jiang J, Wang Y, Sunega J, Dong R, Ma Y, Esparham A, Ferrell R, Levine M, Drisko J, Chen Q. Pharmacokinetic Evaluation of Intravenous Vitamin C: A Classic Pharmacokinetic Study. Clin Pharmacokinet 2022; 61:1237-1249. [PMID: 35750958 PMCID: PMC9439974 DOI: 10.1007/s40262-022-01142-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2022] [Indexed: 02/03/2023]
Abstract
PURPOSE Intravenous vitamin C (IVC) is used in a variety of disorders with limited supporting pharmacokinetic data. Herein we report a pharmacokinetic study in healthy volunteers and cancer participants with IVC doses in the range of 1-100 g. METHODS A pharmacokinetic study was conducted in 21 healthy volunteers and 12 oncology participants. Healthy participants received IVC infusions of 1-100 g; oncology participants received IVC infusions of 25-100 g. Serial blood and complete urine samples were collected pre-infusion and for 24 h post-infusion. Pharmacokinetic parameters were computed using noncompartmental methods. Adverse events were monitored during the study. RESULTS In both cohorts, IVC exhibited first-order kinetics at doses up to 75 g. At 100 g, maximum concentration (Cmax) plateaued in both groups, whereas area under the concentration-time curve (AUC) only plateaued in the healthy group. IVC was primarily excreted through urine. No saturation of clearance was observed; however, the mean 24-h total IVC excretion in urine for all doses was lower in oncology participants (89% of dose) than in healthy participants at 100 g (99%). No significant adverse events were observed; thus, maximum tolerated dose (MTD) was not reached. CONCLUSION IVC followed first-order pharmacokinetics up to 75 g and at up to 100 g had complete renal clearance in 24 h. IVC up to 100 g elicited no adverse effects or significant physiological/biochemical changes and appears to be safe. These data can be used to rectify existing misinformation and to guide future clinical trials. REGISTRATION ClinicalTrials.gov identifier number NCT01833351.
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Affiliation(s)
- Ping Chen
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA
| | - Greg Reed
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA
| | - Joyce Jiang
- Division of Epidemiology, Biostatistics, and Environmental Health School of Public Health, University of Memphis, Memphis, TN, USA
| | - Yaohui Wang
- Molecular and Clinical Nutrition Section, Digestive Diseases Branch, NIDDK, NIH, Bethesda, MD, USA
| | - Jean Sunega
- Department of Rehabilitation Medicine, University of Kansas Medical Center, Kansas City, KS, USA
| | - Ruochen Dong
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA
| | - Yan Ma
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA
| | - Anna Esparham
- Division of Neurology, Children's Mercy Hospital, Kansas City, MO, USA
| | - Ryan Ferrell
- Department or Cardiovascular Medicine, University of Kansas Health System, Kansas City, KS, USA
| | - Mark Levine
- Molecular and Clinical Nutrition Section, Digestive Diseases Branch, NIDDK, NIH, Bethesda, MD, USA
| | - Jeanne Drisko
- Department of Internal Medicine, Integrative Medicine Research, University of Kansas Medical Center, Kansas City, KS, USA.
| | - Qi Chen
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA.
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Abbotts R, Dellomo AJ, Rassool FV. Pharmacologic Induction of BRCAness in BRCA-Proficient Cancers: Expanding PARP Inhibitor Use. Cancers (Basel) 2022; 14:2640. [PMID: 35681619 PMCID: PMC9179544 DOI: 10.3390/cancers14112640] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 05/24/2022] [Accepted: 05/24/2022] [Indexed: 12/17/2022] Open
Abstract
The poly(ADP-ribose) polymerase (PARP) family of proteins has been implicated in numerous cellular processes, including DNA repair, translation, transcription, telomere maintenance, and chromatin remodeling. Best characterized is PARP1, which plays a central role in the repair of single strand DNA damage, thus prompting the development of small molecule PARP inhibitors (PARPi) with the intent of potentiating the genotoxic effects of DNA damaging agents such as chemo- and radiotherapy. However, preclinical studies rapidly uncovered tumor-specific cytotoxicity of PARPi in a subset of cancers carrying mutations in the BReast CAncer 1 and 2 genes (BRCA1/2), which are defective in the homologous recombination (HR) DNA repair pathway, and several PARPi are now FDA-approved for single agent treatment in BRCA-mutated tumors. This phenomenon, termed synthetic lethality, has now been demonstrated in tumors harboring a number of repair gene mutations that produce a BRCA-like impairment of HR (also known as a 'BRCAness' phenotype). However, BRCA mutations or BRCAness is present in only a small subset of cancers, limiting PARPi therapeutic utility. Fortunately, it is now increasingly recognized that many small molecule agents, targeting a variety of molecular pathways, can induce therapeutic BRCAness as a downstream effect of activity. This review will discuss the potential for targeting a broad range of molecular pathways to therapeutically induce BRCAness and PARPi synthetic lethality.
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Affiliation(s)
- Rachel Abbotts
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.J.D.); (F.V.R.)
- University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD 21201, USA
| | - Anna J. Dellomo
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.J.D.); (F.V.R.)
- University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD 21201, USA
| | - Feyruz V. Rassool
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.J.D.); (F.V.R.)
- University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD 21201, USA
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Auranofin and Pharmacologic Ascorbate as Radiomodulators in the Treatment of Pancreatic Cancer. Antioxidants (Basel) 2022; 11:antiox11050971. [PMID: 35624835 PMCID: PMC9137675 DOI: 10.3390/antiox11050971] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 04/27/2022] [Accepted: 05/11/2022] [Indexed: 02/06/2023] Open
Abstract
Pancreatic cancer accounts for nearly one fourth of all new cancers worldwide. Little progress in the development of novel or adjuvant therapies has been made over the past few decades and new approaches to the treatment of pancreatic cancer are desperately needed. Pharmacologic ascorbate (P-AscH−, high-dose, intravenous vitamin C) is being investigated in clinical trials as an adjunct to standard-of-care chemoradiation treatments. In vitro, P-AscH− has been shown to sensitize cancer cells to ionizing radiation in a manner that is dependent on the generation of H2O2 while simultaneously protecting normal tissue from radiation damage. There is renewed interest in Auranofin (Au), an FDA-approved medication utilized in the treatment of rheumatoid arthritis, as an anti-cancer agent. Au inhibits the thioredoxin antioxidant system, thus increasing the overall peroxide burden on cancer cells. In support of current literature demonstrating Au’s effectiveness in breast, colon, lung, and ovarian cancer, we offer additional data that demonstrate the effectiveness of Au alone and in combination with P-AscH− and ionizing radiation in pancreatic cancer treatment. Combining P-AscH− and Au in the treatment of pancreatic cancer may confer multiple mechanisms to increase H2O2-dependent toxicity amongst cancer cells and provide a promising translatable avenue by which to enhance radiation effectiveness and improve patient outcomes.
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Gao L, Chen R, Li T, Li L, Zheng Q. Quantitative Analysis of the Efficacy of PARP Inhibitors as Maintenance Therapy in Recurrent Ovarian Cancer. Front Pharmacol 2021; 12:771836. [PMID: 34819864 PMCID: PMC8606554 DOI: 10.3389/fphar.2021.771836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022] Open
Abstract
Objective: This study aimed to establish a pharmacodynamic model and to screen reasonable covariates to quantitatively describe the efficacy of poly (ADP-ribose) polymerase inhibitors (PARPis) as maintenance treatment for recurrent ovarian cancer (ROC). Methods: The log normal hazard function model was established by using progression-free survival (PFS) data of 1,169 patients from published randomized trials on FDA-approved PARP inhibitors (olaparib, niraparib, and rucaparib). Monte Carlo simulation was used to compare PFS values in different scenarios, such as monotherapy (administered alone) and combination therapy (PARPis combined with chemo- or target-therapies), different biomarker statuses, and different PARP inhibitors. PFS was also estimated. Results: The study showed that the median PFS was 8.5 months with monotherapy and 16.0 months with combination therapy. The median PFS of patients with the BRCA mutation, BRCA wild-type, and HRD-positivity were 11.0, 7.5, and 9.0 months in monotherapy, respectively, and 23.0, 14.0 and 17.5 months, in combination therapy, respectively. In addition, the median PFS of olaparib, niraparib, and rucaparib monotherapy were about 9.5, 10.5, and 12.0 months, respectively, and about 19.0, 20.0, and 25 months, respectively, in combination therapy. The median PFS values in combination with cediranib, bevacizumab, and chemotherapy were approximately 17.0, 12.5 and 19.5 months, respectively. Conclusion: PARPi combination therapy is more effective as maintenance treatment for ROC than monotherapy, and the efficacy of PARPis in combination with chemotherapy is higher than that of the combination with antiangiogenic drugs. We found that the PFS of BRCA wild-type was similar to that of HRD-positive patients, and there was no significant difference in PFS between olaparib, niraparib, and rucaparib, which provides necessary quantitative information for the clinical practice of PARPis in the treatment of ROC.
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Affiliation(s)
- Lili Gao
- Center for Drug Clinical Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Rui Chen
- Center for Drug Clinical Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Ting Li
- Center for Drug Clinical Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Lujin Li
- Center for Drug Clinical Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Qingshan Zheng
- Center for Drug Clinical Research, Shanghai University of Traditional Chinese Medicine, Shanghai, China
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High-Dose Vitamin C: Preclinical Evidence for Tailoring Treatment in Cancer Patients. Cancers (Basel) 2021; 13:cancers13061428. [PMID: 33804775 PMCID: PMC8003833 DOI: 10.3390/cancers13061428] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/02/2021] [Accepted: 03/16/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary Vitamin C is an indispensable micronutrient in the human diet due to the multiple functions it carries out in the body. Reports of clinical studies have indicated that, when administered at high dosage by the intravenous route, vitamin C may exert beneficial antitumor effects in patients with advanced stage cancers, including those refractory to previous treatment with chemotherapy. The aim of this article is to provide an overview of the current scientific evidence concerning the different mechanisms of action by which high-dose vitamin C may kill tumor cells. A special focus will be given to those mechanisms that provide the rationale basis for tailoring vitamin C treatment according to specific molecular alterations present in the tumor and for the selection of the most appropriate companion drugs. Abstract High-dose vitamin C has been proposed as a potential therapeutic approach for patients with advanced tumors who failed previous treatment with chemotherapy. Due to vitamin C complex pharmacokinetics, only intravenous administration allows reaching sufficiently high plasma concentrations required for most of the antitumor effects observed in preclinical studies (>0.250 mM). Moreover, vitamin C entry into cells is tightly regulated by SVCT and GLUT transporters, and is cell type-dependent. Importantly, besides its well-recognized pro-oxidant effects, vitamin C modulates TET enzymes promoting DNA demethylation and acts as cofactor of HIF hydroxylases, whose activity is required for HIF-1α proteasomal degradation. Furthermore, at pharmacological concentrations lower than those required for its pro-oxidant activity (<1 mM), vitamin C in specific genetic contexts may alter the DNA damage response by increasing 5-hydroxymethylcytosine levels. These more recently described vitamin C mechanisms offer new treatment opportunities for tumors with specific molecular defects (e.g., HIF-1α over-expression or TET2, IDH1/2, and WT1 alterations). Moreover, vitamin C action at DNA levels may provide the rationale basis for combination therapies with PARP inhibitors and hypomethylating agents. This review outlines the pharmacokinetic and pharmacodynamic properties of vitamin C to be taken into account in designing clinical studies that evaluate its potential use as anticancer agent.
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