Abstract
Background: Anaplastic thyroid cancer is an aggressive and fatal malignancy. Many advanced cancers are characterized by glucose dependency, leading to oxidative stress and cellular proliferation. Therefore, we sought to determine if a low glucose environment (in vitro) or a ketogenic diet (in vivo) could inhibit anaplastic thyroid cancer tumor growth when combined with the antioxidant N-acetylcysteine. Methods: In vivo, nude mice were injected with the anaplastic thyroid cancer cell line 8505C (n = 6/group). Group 1 was fed a standard diet; Group 2 was fed a ketogenic diet; Group 3 was given standard diet with N-acetylcysteine (40 mM in the drinking water); and Group 4 was fed ketogenic diet with N-acetylcysteine. Tumor volumes, ketones, and glucose were measured. H&E stains and immunohistochemistry for Ki-67 and Caspase 3 were performed on the tumors. In vitro, 8505C cells were cultured in high glucose (25 mM), low glucose (3 mM), high glucose plus N-acetylcysteine (200 uM), or low glucose plus N-acetylcysteine for 96 hours. We performed CyQUANT proliferation (Thermo Fisher Scientific, Waltham, MA), Seahorse glycolytic stress (Agilent, Santa Clara, CA), and reactive oxidative stress assays. Results: Ketogenic diet plus N-acetylcysteine decreased in vivo tumor volume compared to standard diet (22.5 ± 12.4 mm3 vs 147 ± 54.4 mm3, P < .05) and standard diet plus N-acetylcysteine (P < .05). Blood ketone levels were significantly higher for the mice in the ketogenic diet group compared to standard diet (1.74 mmol/L vs 0.38 mmol/L at week 5, P < .001). However, blood glucose levels were not significantly different between ketogenic diet and standard diet groups. Cells cultured in low glucose plus N-acetylcysteine had significantly reduced proliferation compared to high glucose (98.1 ± 5.0 relative fluorescence units vs 157.8 ± 2.1 relative fluorescence units, P < .001). Addition of N-acetylcysteine to low glucose lowered glycolysis function compared to high glucose (39.0 ± 2.2 mpH/min/cell vs 89.1 ± 13.2 mpH/min/cell, P < .001) and high glucose plus N-acetylcysteine (37.4 ± 2.5 mpH/min/cell vs 70.3 ± 3.3 mpH/min/cell, P < .001). Low glucose plus N-acetylcysteine decreased reactive oxidative stress compared to high glucose (119 ± 34.7 relative fluorescence units vs 277 ± 16.0 relative fluorescence units, P = .014). Conclusion: The combination of a ketogenic diet or glucose restriction with the antioxidant- N-acetylcysteine significantly reduced tumor growth in vivo and in vitro. Further studies are warranted to explore these metabolic therapies in anaplastic thyroid cancer.
Original language | English (US) |
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Pages (from-to) | 87-93 |
Number of pages | 7 |
Journal | Surgery (United States) |
Volume | 167 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2020 |
Funding
Authors Abha Aggarwal, Zuliang Yuan, Justine A. Barletta, and Matthew A. Nehs do not have any conflicts of interest. Dr. Jochen H. Lorch has research that is supported by Novartis , Bayer , BMG , and Millennium . Dr. Lorch also receives consulting honoraria from Bayer and Genentech. Our in vitro data support the in vivo findings: the cells cultured in LG supplemented with NAC showed a significantly lower cellular proliferation, reactive oxygen species-mediated oxidative stress, and glycolytic stress when compared to the cells cultured in HG media. Mechanistically, our study showed that restricting glucose in combination with antioxidant NAC results in decreased glycolytic stress and inhibition of ROS signaling, thereby reducing tumor cell proliferation.This study was funded by the Robert T. Osteen Fellowship Award and the Department of Surgery, Brigham and Women's Hospital, Boston, MA.Authors Abha Aggarwal, Zuliang Yuan, Justine A. Barletta, and Matthew A. Nehs do not have any conflicts of interest. Dr. Jochen H. Lorch has research that is supported by Novartis, Bayer, BMG, and Millennium. Dr. Lorch also receives consulting honoraria from Bayer and Genentech. This study was funded by the Robert T. Osteen Fellowship Award and the Department of Surgery , Brigham and Women's Hospital , Boston, MA.
ASJC Scopus subject areas
- Surgery