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Thim EA, Fox T, Deering T, Vass LR, Sheybani ND, Kester M, Price RJ. Solid tumor treatment via augmentation of bioactive C6 ceramide levels with thermally ablative focused ultrasound. Drug Deliv Transl Res 2023; 13:3145-3153. [PMID: 37335416 DOI: 10.1007/s13346-023-01377-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2023] [Indexed: 06/21/2023]
Abstract
Sparse scan partial thermal ablation (TA) with focused ultrasound (FUS) may be deployed to treat solid tumors and increase delivery of systemically administered therapeutics. Furthermore, C6-ceramide-loaded nanoliposomes (CNLs), which rely upon the enhanced-permeation and retention (EPR) effect for delivery, have shown promise for treating solid tumors and are being tested in clinical trials. Here, our objective was to determine whether CNLs synergize with TA in the control of 4T1 breast tumors. CNL monotherapy of 4T1 tumors yielded significant intratumoral bioactive C6 accumulation by the EPR effect, but tumor growth was not controlled. TA increased bioactive C6 accumulation by ~ 12.5-fold over the EPR effect. In addition, TA + CNL caused shifts in long-chain to very-long-chain ceramide ratios (i.e., C16/24 and C18/C24) that could potentially contribute to tumor control. Nonetheless, these changes in intratumoral ceramide levels were still insufficient to confer tumor growth control beyond that achieved when combining with TA with control "ghost" nanoliposomes (GNL). While this lack of synergy could be due to increased "pro-tumor" sphingosine-1-phosphate (S1P) levels, this is unlikely because S1P levels exhibited only a moderate and statistically insignificant increase with TA + CNL. In vitro studies showed that 4T1 cells are highly resistant to C6, offering the most likely explanation for the inability of TA to synergize with CNL. Thus, while our results show that sparse scan TA is a powerful approach for markedly enhancing CNL delivery and generating "anti-tumor" shifts in long-chain to very-long-chain ceramide ratios, resistance of the tumor to C6 can still be a rate-limiting factor for some solid tumor types.
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Affiliation(s)
- E Andrew Thim
- Department of Biomedical Engineering, University of Virginia, Box 800759, Charlottesville, VA, 22908, USA
| | - Todd Fox
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Tye Deering
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Luke R Vass
- Department of Pathology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Natasha D Sheybani
- Department of Biomedical Engineering, University of Virginia, Box 800759, Charlottesville, VA, 22908, USA
| | - Mark Kester
- Department of Biomedical Engineering, University of Virginia, Box 800759, Charlottesville, VA, 22908, USA
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Richard J Price
- Department of Biomedical Engineering, University of Virginia, Box 800759, Charlottesville, VA, 22908, USA.
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Thim EA, Fox T, Deering T, Vass LR, Sheybani ND, Kester M, Price RJ. Solid Tumor Treatment via Augmentation of Bioactive C6 Ceramide Levels with Thermally Ablative Focused Ultrasound. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.23.532394. [PMID: 36993445 PMCID: PMC10055354 DOI: 10.1101/2023.03.23.532394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Sparse scan partial thermal ablation (TA) with focused ultrasound (FUS) may be deployed to treat solid tumors and increase delivery of systemically administered therapeutics. Further, C6-ceramide-loaded nanoliposomes (CNLs), which rely upon the enhanced permeation and retention (EPR) effect for delivery, have shown promise for treating solid tumors and are being tested in clinical trials. Here, our objective was to determine whether CNLs synergize with TA in the control of 4T1 breast tumors. CNL-monotherapy of 4T1 tumors yielded significant intratumoral bioactive C6 accumulation by the EPR effect, but tumor growth was not controlled. TA increased bioactive C6 accumulation by ∼12.5-fold over the EPR effect. In addition, TA+CNL caused shifts in long-chain to very-long-chain ceramide ratios (i.e., C16/24 and C18/C24) that could potentially contribute to tumor control. Nonetheless, these changes in intratumoral ceramide levels were still insufficient to confer tumor growth control beyond that achieved when combining with TA with control "ghost" nanoliposomes (GNL). While this lack of synergy could be due to increased "pro-tumor" sphingosine-1-phosphate (S1P) levels, this is unlikely because S1P levels exhibited only a moderate and statistically insignificant increase with TA+CNL. In vitro studies showed that 4T1 cells are highly resistant to C6, offering the most likely explanation for the inability of TA to synergize with CNL. Thus, while our results show that sparse scan TA is a powerful approach for markedly enhancing CNL delivery and generating "anti-tumor" shifts in long-chain to very-long-chain ceramide ratios, resistance of the tumor to C6 can still be a rate-limiting factor for some solid tumor types.
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Affiliation(s)
- E. Andrew Thim
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908
| | - Todd Fox
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908
| | - Tye Deering
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908
| | - Luke R. Vass
- Department of Pathology, University of Virginia, Charlottesville, VA 22908
| | - Natasha D. Sheybani
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908
| | - Mark Kester
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908
| | - Richard J. Price
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908
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Applications of Ultrasound to Stimulate Therapeutic Revascularization. Int J Mol Sci 2019; 20:ijms20123081. [PMID: 31238531 PMCID: PMC6627741 DOI: 10.3390/ijms20123081] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 06/20/2019] [Accepted: 06/21/2019] [Indexed: 12/13/2022] Open
Abstract
Many pathological conditions are characterized or caused by the presence of an insufficient or aberrant local vasculature. Thus, therapeutic approaches aimed at modulating the caliber and/or density of the vasculature by controlling angiogenesis and arteriogenesis have been under development for many years. As our understanding of the underlying cellular and molecular mechanisms of these vascular growth processes continues to grow, so too do the available targets for therapeutic intervention. Nonetheless, the tools needed to implement such therapies have often had inherent weaknesses (i.e., invasiveness, expense, poor targeting, and control) that preclude successful outcomes. Approximately 20 years ago, the potential for using ultrasound as a new tool for therapeutically manipulating angiogenesis and arteriogenesis began to emerge. Indeed, the ability of ultrasound, especially when used in combination with contrast agent microbubbles, to mechanically manipulate the microvasculature has opened several doors for exploration. In turn, multiple studies on the influence of ultrasound-mediated bioeffects on vascular growth and the use of ultrasound for the targeted stimulation of blood vessel growth via drug and gene delivery have been performed and published over the years. In this review article, we first discuss the basic principles of therapeutic ultrasound for stimulating angiogenesis and arteriogenesis. We then follow this with a comprehensive cataloging of studies that have used ultrasound for stimulating revascularization to date. Finally, we offer a brief perspective on the future of such approaches, in the context of both further research development and possible clinical translation.
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