Selenium (Se) is an essential trace element, naturally present in many foods, and has been used as a supplement for the prevention or control of cancer including hepatocellular carcinoma.[1,2] Until recently, only bulk Se content could be measured in biological samples, but recent technological development provided the basis to quantify space-resolved single cell selenium distribution in tissues. Over the past decade, LA-ICP-TOFMS has become a powerful imaging tool for detection of endogenous elements, metal-based anticancer drugs, and elements from metal-labeled antibodies in tissue samples.[3,4] This technique offers promising applications in cancer research, proteomics, metallomics, and the broader medical sector, providing a robust approach for understanding the role of metals in biological systems.

However, Se detection remains generally challenging due to spectral interferences affecting several isotopes. Modern reaction/collision cell technology (CCT) can significantly attenuate these interferences, ensuring accurate results. [5] In this study, subcellular Se levels were measured in FFPE embedded liver tissues of rats with chemically induced hepatocarcinogenesis and Se supplementation.[2] To detect subcellular Se distribution, Laser Ablation Inductively Coupled Plasma Time-of-Flight Mass Spectrometry (LA-ICP-TOFMS) was used. Thus, the first part of this study focuses on optimizing the figures of merit for Se detection by ICP-TOFMS. Subsequently, data analysis was conducted using MeXpose, an advanced image analysis pipeline designed for spatial single-cell metallomics.[6] In addition to quantifying Se at the single-cell level, MeXpose enables the visualization of structural features and immune cells via metal-labeled antibodies, along with the detection of endogenous elements, allowing for a multiplex imaging approach. This workflow offers deeper insights into the relationship between Se exposure and liver tumor development at single-cell resolution, contributing to the broader understanding of selenium’s role in cancer prevention.

References

[1] F. B. Raymond et al, Cancer Epidemiology,Biomarkers & Prevention, 2006, 15, 804-810.
[2] N. Rohr-Udilova et al, Hepatology, 2012, 55(4), 1112-1121
[3] Van Malderen et al., J. Anal. Spectrom., 2016, 31, 423-439
[4] S. Theiner et al, Analytical Chemistry, 2019, 13, 8207-8212
[5] S. Tanner et al, Spectrochimica Acta Part B, 2002, 57, 1361–1452
[6] G. Braun et al, JACS Au, 2024, 4, 2197-2210.