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Wright C, Simone NL. Obesity and tumor growth: inflammation, immunity, and the role of a ketogenic diet. Curr Opin Clin Nutr Metab Care 2016; 19:294-9. [PMID: 27168354 DOI: 10.1097/mco.0000000000000286] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE OF REVIEW This article reviews the impact the obese state has on malignancy through inflammation and immune dysregulation using recent excerpts from the medical literature. RECENT FINDINGS The obese state creates a proinflammatory endocrinologic milieu altering cellular signaling between adipocytes, immunologic cells, and epithelial cells, leading to the over-activation of adipose tissue macrophages and the upregulation of compounds associated with carcinogenesis. Obesity correlates with a deficiency in numerous immunologic cells, including dendritic cells, natural killer cells, and T cells. In part, this can be attributed to a recent finding of leptin receptor expression on these immune cells and the upregulation of leptin signaling in the obese state. A number of clinical trials have demonstrated the feasibility of a high-fat, low-carbohydrate diet as an adjuvant treatment for cancer, and current trials are investigating the impact of this intervention on disease outcomes. In preclinical trials, a ketogenic diet has been shown to impede tumor growth in a variety of cancers through anti-angiogenic, anti-inflammatory, and proapoptotic mechanisms. SUMMARY Obesity is becoming more prevalent and its link to cancer is clearly established providing a rationale for the implementation of dietary interventions as an adjuvant therapeutic strategy for malignancy.
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Affiliation(s)
- Christopher Wright
- aSidney Kimmel Medical College at Thomas Jefferson University bDepartment of Radiation Oncology, Sidney Kimmel Cancer Center at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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Klement RJ, Champ CE, Otto C, Kämmerer U. Anti-Tumor Effects of Ketogenic Diets in Mice: A Meta-Analysis. PLoS One 2016; 11:e0155050. [PMID: 27159218 PMCID: PMC4861343 DOI: 10.1371/journal.pone.0155050] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 04/22/2016] [Indexed: 02/07/2023] Open
Abstract
Background Currently ketogenic diets (KDs) are hyped as an anti-tumor intervention aimed at exploiting the metabolic abnormalities of cancer cells. However, while data in humans is sparse, translation of murine tumor models to the clinic is further hampered by small sample sizes, heterogeneous settings and mixed results concerning tumor growth retardation. The aim was therefore to synthesize the evidence for a growth inhibiting effect of KDs when used as a monotherapy in mice. Methods We conducted a Bayesian random effects meta-analysis on all studies assessing the survival (defined as the time to reach a pre-defined endpoint such as tumor volume) of mice on an unrestricted KD compared to a high carbohydrate standard diet (SD). For 12 studies meeting the inclusion criteria either a mean survival time ratio (MR) or hazard ratio (HR) between the KD and SD groups could be obtained. The posterior estimates for the MR and HR averaged over four priors on the between-study heterogeneity τ2 were MR = 0.85 (95% highest posterior density interval (HPDI) = [0.73, 0.97]) and HR = 0.55 (95% HPDI = [0.26, 0.87]), indicating a significant overall benefit of the KD in terms of prolonged mean survival times and reduced hazard rate. All studies that used a brain tumor model also chose a late starting point for the KD (at least one day after tumor initiation) which accounted for 26% of the heterogeneity. In this subgroup the KD was less effective (MR = 0.89, 95% HPDI = [0.76, 1.04]). Conclusions There was an overall tumor growth delaying effect of unrestricted KDs in mice. Future experiments should aim at differentiating the effects of KD timing versus tumor location, since external evidence is currently consistent with an influence of both of these factors.
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Affiliation(s)
- Rainer J Klement
- Department of Radiotherapy and Radiation Oncology, Leopoldina Hospital Schweinfurt, Schweinfurt, Germany
| | - Colin E Champ
- Department of Radiation Oncology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - Christoph Otto
- Department of General, Visceral, Vascular and Pediatric Surgery, University Hospital of Würzburg, Würzburg, Germany
| | - Ulrike Kämmerer
- Department of Obstetrics and Gynaecology, University Hospital of Würzburg, Würzburg, Germany
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Klement RJ, Fink MK. Dietary and pharmacological modification of the insulin/IGF-1 system: exploiting the full repertoire against cancer. Oncogenesis 2016; 5:e193. [PMID: 26878387 PMCID: PMC5154349 DOI: 10.1038/oncsis.2016.2] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 11/10/2015] [Accepted: 11/16/2015] [Indexed: 12/19/2022] Open
Abstract
As more and more links between cancer and metabolism are discovered, new approaches to treat cancer using these mechanisms are considered. Dietary restriction of either calories or macronutrients has shown great potential in animal studies to both reduce the incidence and growth of cancer, and to act synergistically with other treatment strategies. These studies have also shown that dietary restriction simultaneously targets many of the molecular pathways that are targeted individually by anticancer drugs. The insulin/insulin-like growth factor-1 (IGF-1) system has thereby emerged as a key regulator of cancer growth pathways. Although lowering of insulin levels with diet or drugs such as metformin and diazoxide seems generally beneficial, some practitioners also utilize strategic elevations of insulin levels in combination with chemotherapeutic drugs. This indicates a broad spectrum of possibilities for modulating the insulin/IGF-1 system in cancer treatment. With a specific focus on dietary restriction, insulin administration and the insulin-lowering drug diazoxide, such modifications of the insulin/IGF-1 system are the topic of this review. Although preclinical data are promising, we point out that insulin regulation and the metabolic response to a certain diet often differ between mice and humans. Thus, the need for collecting more human data has to be emphasized.
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Affiliation(s)
- R J Klement
- Department of Radiation Oncology, Leopoldina Hospital Schweinfurt, Schweinfurt, Germany
| | - M K Fink
- Onkologische Praxis, Fürth, Germany
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Martuscello RT, Vedam-Mai V, McCarthy DJ, Schmoll ME, Jundi MA, Louviere CD, Griffith BG, Skinner CL, Suslov O, Deleyrolle LP, Reynolds BA. A Supplemented High-Fat Low-Carbohydrate Diet for the Treatment of Glioblastoma. Clin Cancer Res 2015; 22:2482-95. [PMID: 26631612 DOI: 10.1158/1078-0432.ccr-15-0916] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 11/12/2015] [Indexed: 11/16/2022]
Abstract
PURPOSE Dysregulated energetics coupled with uncontrolled proliferation has become a hallmark of cancer, leading to increased interest in metabolic therapies. Glioblastoma (GB) is highly malignant, very metabolically active, and typically resistant to current therapies. Dietary treatment options based on glucose deprivation have been explored using a restrictive ketogenic diet (KD), with positive anticancer reports. However, negative side effects and a lack of palatability make the KD difficult to implement in an adult population. Hence, we developed a less stringent, supplemented high-fat low-carbohydrate (sHFLC) diet that mimics the metabolic and antitumor effects of the KD, maintains a stable nutritional profile, and presents an alternative clinical option for diverse patient populations. EXPERIMENTAL DESIGN The dietary paradigm was tested in vitro and in vivo, utilizing multiple patient-derived gliomasphere lines. Cellular proliferation, clonogenic frequency, and tumor stem cell population effects were determined in vitro using the neurosphere assay (NSA). Antitumor efficacy was tested in vivo in preclinical xenograft models and mechanistic regulation via the mTOR pathway was explored. RESULTS Reducing glucose in vitro to physiologic levels, coupled with ketone supplementation, inhibits proliferation of GB cells and reduces tumor stem cell expansion. In vivo, while maintaining animal health, the sHFLC diet significantly reduces the growth of tumor cells in a subcutaneous model of tumor progression and increases survival in an orthotopic xenograft model. Dietary-mediated anticancer effects correlate with the reduction of mTOR effector expression. CONCLUSIONS We demonstrate that the sHFLC diet is a viable treatment alternative to the KD, and should be considered for clinical testing. Clin Cancer Res; 22(10); 2482-95. ©2015 AACR.
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Affiliation(s)
- Regina T Martuscello
- Department of Neurosurgery, College of Medicine, University of Florida, Gainesville, Florida. Interdisciplinary Program in Biomedical Sciences, Neuroscience, College of Medicine, University of Florida, Gainesville, Florida
| | - Vinata Vedam-Mai
- Department of Neurosurgery, College of Medicine, University of Florida, Gainesville, Florida. Center for Movement Disorders and Neuro-restoration, University of Florida, Gainesville, Florida
| | - David J McCarthy
- Department of Neurosurgery, College of Medicine, University of Florida, Gainesville, Florida
| | - Michael E Schmoll
- Department of Neurosurgery, College of Medicine, University of Florida, Gainesville, Florida
| | - Musa A Jundi
- Department of Neurosurgery, College of Medicine, University of Florida, Gainesville, Florida
| | - Christopher D Louviere
- Department of Neurosurgery, College of Medicine, University of Florida, Gainesville, Florida
| | - Benjamin G Griffith
- Department of Neurosurgery, College of Medicine, University of Florida, Gainesville, Florida
| | - Colby L Skinner
- Department of Neurosurgery, College of Medicine, University of Florida, Gainesville, Florida
| | - Oleg Suslov
- Department of Neurosurgery, College of Medicine, University of Florida, Gainesville, Florida
| | - Loic P Deleyrolle
- Department of Neurosurgery, College of Medicine, University of Florida, Gainesville, Florida.
| | - Brent A Reynolds
- Department of Neurosurgery, College of Medicine, University of Florida, Gainesville, Florida. Interdisciplinary Program in Biomedical Sciences, Neuroscience, College of Medicine, University of Florida, Gainesville, Florida.
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