# Cannabidiol does not cause DNA double-strand breaks in a human liver-derived cell model

## TL;DR

This study shows that cannabidiol (CBD) does not cause DNA damage in liver cells, but it does reduce cell growth and increase a signaling molecule.

## Contribution

The study provides new evidence that CBD does not induce DNA double-strand breaks in HepG2 liver cells, addressing prior concerns about its genotoxicity.

## Key findings

- CBD reduced CB2 receptor expression in a dose-dependent manner in HepG2 cells.
- CBD did not increase DNA double-strand breaks in HepG2 cells compared to controls.
- CBD treatment reduced cell proliferation and increased intracellular cAMP levels.

## Abstract

Cannabidiol (CBD) is a non-psychoactive cannabinoid with potential therapeutic applications, including anti-inflammatory, analgesic, and anticancer effects. However, experts raised concerns about its potential to induce DNA damage and chromosomal aberrations at low concentrations. Notably, these studies used liver cell lines, which may not fully reflect the metabolic processing of CBD, potentially limiting the generalizability of their findings. This study investigated the short time effects of CBD on DNA double-strand breaks (DSBs) and proliferation in the human liver-derived cell line HepG2.

HepG2 cells were treated with CBD (5 – 50 \documentclass[12pt]{minimal}
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\begin{document}$$\mu M$$\end{document}, 3 - 72h incubation). To investigate potential imbalances in the expression of cannabinoid receptors 1 and 2 (CB1 / CB2) within HepG2 cells, we examined their expression using Western blot analysis. We hypothesized that such an imbalance could be associated with pathogenic processes. Double-strand breaks were then detected (5 \documentclass[12pt]{minimal}
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\begin{document}$$\mu M$$\end{document} Etoposide (ETP) served as positive control) via indirect immunofluorescence analysis using \documentclass[12pt]{minimal}
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\begin{document}$$\gamma$$\end{document} H2AX and 53BP1 antibodies, followed by quantification of DSB foci.

Expression of CB2 but not CB1 was downregulated by 30 % in HepG2 cells after exposure to 5 \documentclass[12pt]{minimal}
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\begin{document}$$\mu M$$\end{document} CBD (24h incubation; \documentclass[12pt]{minimal}
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\begin{document}$$p<$$\end{document}0.05) and 70 % downregulated after exposure to 50 \documentclass[12pt]{minimal}
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\begin{document}$$\mu M$$\end{document} CBD (24h incubation; \documentclass[12pt]{minimal}
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\begin{document}$$p<$$\end{document}0.01). This effect was dose-dependent. Whilst ETP induced dose dependent DSBs, we could not confirm findings by others that CBD significantly increases the number of \documentclass[12pt]{minimal}
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\begin{document}$$\gamma$$\end{document} H2AX and 53BP1 foci between 5 \documentclass[12pt]{minimal}
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\begin{document}$$\mu M$$\end{document} and 50 \documentclass[12pt]{minimal}
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\begin{document}$$\mu M$$\end{document} (3h incubation; \documentclass[12pt]{minimal}
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\begin{document}$$p<$$\end{document}0.05).

In our model, CBD stimulated the cells, as confirmed by modulation of CB2 expression as well as changes in intracellular cAMP. Our results show that CBD in ranges between 5 \documentclass[12pt]{minimal}
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\begin{document}$$\mu M$$\end{document} to 50 \documentclass[12pt]{minimal}
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\begin{document}$$\mu M$$\end{document} does not significantly increase the amount of DNA double strand breaks in HepG2 cells compared to the control. However, we did observe a significant reduction in cell proliferation and a significant increase in intracellular cAMP levels following CBD treatment.

The online version contains supplementary material available at 10.1186/s42238-025-00365-w.