Extracellular vesicles isolated from fresh vs frozen melanoma tissues are similar in purity, protein composition, and tumor antigenicity

ABSTRACT: Extracellular vesicles (EVs) are nano-sized particles released by cells, enriched in disease-related molecules, gaining attention as potential tumor biomarkers and useful tools for cancer immunotherapy. Tumor tissues are valuable sources of EVs, reflecting the tumor's molecular profile. This study investigates whether freezing tumor tissues affects the integrity and functionality of EVs and whether non-EV components contaminate them. We compared the purity and protein composition of EVs isolated from human metastatic melanoma tissue, analyzing both fresh and frozen samples. EVs were isolated using ultracentrifugation and an iodixanol density cushion, and characterized by transmission electron microscopy, nanoparticle tracking analysis, and mass spectrometry. Results showed no significant differences in purity, protein composition, or diagnostic potential between EVs from fresh and frozen tissues. Similar levels of melanoma-associated EV surface molecules were detected, with no signs of excess protein contamination in frozen tissue-derived EVs. Furthermore, we demonstrated that EVs from frozen mouse melanoma, when combined with synthetic bacterial vesicles, reduced tumor growth in melanoma-bearing mice to a similar extent as fresh tissue-derived EVs. This study supports the use of frozen tissues as a reliable EV source, as frozen tissue-derived EVs exhibit comparable purity, protein composition, diagnostic potential, and tumor antigenicity to those from fresh tissues.

INSTRUMENT(S):

ORGANISM(S): Homo Sapiens (human)

SUBMITTER: Johannes Fuchs  

LAB HEAD: Rossella Crescitelli

PROVIDER: PXD068552 | Pride | 2026-06-01

REPOSITORIES: Pride