Dark tea-derived exosome-like nanovesicles suppress hepatocellular carcinoma via inhibiting Akt pathway and modulating immune profiles.

BACKGROUND

Accumulating evidence indicates the microbial fermentation enhanced the health benefits and potential anti-tumor effect of dark tea. However, low bioavailability and unclarified therapeutic mechanisms impeded its deeply application. Plant-derived exosome-like nanoparticles offered a promising option for improving bioavailability and targeted delivery capability.

PURPOSE: To obtain dark tea-derived exosome-like nanovesicles (DTELNs) and clarify their material basis, investigate the therapeutic effects on hepatocyte carcinoma (HCC) and potential mechanisms.

METHODS

DTELNs were isolated by tangential flow filtration, TEM, NTA, nucleic acid & protein analysis system and LC-MS/MS were used to characterize their morphological characteristics and chemical composition. Orthotopic HCC model mice were established and employed for DTELNs' oral administration. Living imaging, H&E staining and biochemical assays were used to evaluate therapeutic effects. Untargeted metabolomic, 16S rRNA sequencing and cytometry by time-of-flight (CyTOF) were used to investigate the alteration of endogenous substances and immune features. Potential targets were explored by network pharmacology, protein-protein interaction, and verified by western blot. Finally, HCC patient-derived organoids were generated to evaluate the clinical applicability of DTELNs.

RESULTS

DTELNs exhibited typical exosomal features, major components including flavonoids, phenolic acids, lipids, amino acids and their derivatives, and miRNAs. DTELNs markedly suppressed tumor proliferation, modulated gut microbial diversity, normalized liver-gut axis physiological homeostasis and enhanced immune responses. DTELNs distinctly downregulated the expressions of p-Akt, NF-κB, Bcl-2, cyclin D1, upregulated the expressions of p-p53, PTEN, Bax, cleaved-caspase 3 and p21. DTELNs also exhibited potent inhibitory effect on HCC organoids.

CONCLUSION

DTELNs demonstrated potent therapeutic efficacy against HCC. The mechanisms mainly involved directly modulating Akt-related signalling pathways, rebalancing gut microbiota and related metabolites, and further boosting anti-tumor immune responses.