Positron emission tomography imaging of the sodium iodide symporter senses real-time energy stress in vivo

Dzien, P. et al. (2023) Positron emission tomography imaging of the sodium iodide symporter senses real-time energy stress in vivo. Cancer and Metabolism, 11, 14. (doi: 10.1186/s40170-023-00314-2) (PMID:37679822) (PMCID:PMC10486058)

Abstract

Background: Tissue environment is critical in determining tumour metabolic vulnerability. However, in vivo drug testing is slow and waiting for tumour growth delay may not be the most appropriate endpoint for metabolic treatments. An in vivo method for measuring energy stress would rapidly determine tumour targeting in a physiologically relevant environment. The sodium-iodide symporter (NIS) is an imaging reporter gene whose protein product co-transports sodium and iodide, and positron emission tomography (PET) radiolabelled anions into the cell. Here, we show that PET imaging of NIS-mediated radiotracer uptake can rapidly visualise tumour energy stress within minutes following in vivo treatment. Methods: We modified HEK293T human embryonic kidney cells, and A549 and H358 lung cancer cells to express transgenic NIS. Next, we subjected these cells and implanted tumours to drugs known to induce metabolic stress to observe the impact on NIS activity and energy charge. We used [18F]tetrafluoroborate positron emission tomography (PET) imaging to non-invasively image NIS activity in vivo. Results: NIS activity was ablated by treating HEK293T cells in vitro, with the Na+/K+ ATPase inhibitor digoxin, confirming that radiotracer uptake was dependent on the sodium–potassium concentration gradient. NIS-mediated radiotracer uptake was significantly reduced (− 58.2%) following disruptions to ATP re-synthesis by combined glycolysis and oxidative phosphorylation inhibition in HEK293T cells and by oxidative phosphorylation inhibition (− 16.6%) in A549 cells in vitro. PET signal was significantly decreased (− 56.5%) within 90 min from the onset of treatment with IACS-010759, an oxidative phosphorylation inhibitor, in subcutaneous transgenic A549 tumours in vivo, showing that NIS could rapidly and sensitively detect energy stress non-invasively, before more widespread changes to phosphorylated AMP-activated protein kinase, phosphorylated pyruvate dehydrogenase, and GLUT1 were detectable. Conclusions: NIS acts as a rapid metabolic sensor for drugs that lead to ATP depletion. PET imaging of NIS could facilitate in vivo testing of treatments targeting energetic pathways, determine drug potency, and expedite metabolic drug development.

• Item Type: Articles
• Additional Information: We would like to acknowledge funding from Cancer Research UK for core funding to the CRUK Beatson Institute (A13827), to David Lewis’ laboratory (A25006) and to the CRUK Glasgow Centre (A25142), Beatson Cancer Charity and Beatson Endowment.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Lewis, Dr David and Malviya, Dr Gaurav and Nixon, Mr Colin and Dzien, Dr Piotr and Johnson, Ms Emma and Blyth, Professor Karen and Maddocks, Professor Oliver
• Authors: Dzien, P., Mackintosh, A., Malviya, G., Johnson, E., Soloviev, D., Brown, G., Huerta Uribe, A., Nixon, C., Lyons, S. K., Maddocks, O., Blyth, K., and Lewis, D.
• College/School: College of Medical Veterinary and Life Sciences > School of Cancer Sciences
• Journal Name: Cancer and Metabolism
• Publisher: BioMed Central
• ISSN: 2049-3002
• ISSN (Online): 2049-3002
• Copyright Holders: Copyright © 2023 The Authors
• First Published: First published in Cancer and Metabolism 11:14
• Publisher Policy: Reproduced under a Creative Commons License

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
174115		CRUK Centre Renewal	Owen Sansom	Cancer Research UK (CRUK)	C7932/A25142	SCS - Beatson Institute for Cancer Research