Proteome profiling of salivary small extracellular vesicles in glioblastoma patients

• Published in: Cancer Vol. 129; no. 18; pp. 2836 - 2847
• Main Authors: Müller Bark, Juliana, Trevisan França de Lima, Lucas, Zhang, Xi, Broszczak, Daniel, Leo, Paul J., Jeffree, Rosalind L., Chua, Benjamin, Day, Bryan W., Punyadeera, Chamindie
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 15.09.2023; John Wiley and Sons Inc
• Subjects: Aldolase; Apoptosis; Biomarkers; Biomarkers - metabolism; Blood-brain barrier; Brain cancer; Cargo; Cell cycle; Cell death; Cell size; Cell surface; Centrifugation; Cytology; Extracellular vesicles; Extracellular Vesicles - metabolism; Extracellular Vesicles - pathology; Gene set enrichment analysis; Glioblastoma; Glioblastoma - pathology; Glioma; Glioma - pathology; Humans; Immune system; Mass spectrometry; Mass spectroscopy; Oncology; Original; ORIGINAL ARTICLES; Proteins; Proteome - metabolism; Proteomes; proteomics; Saliva; Statistical analysis; Ultracentrifugation; Vesicles; saliva; mass spectrometry; extracellular vesicles; glioblastoma; proteomics; biomarkers
• ISSN: 0008-543X; 1097-0142
• DOI: 10.1002/cncr.34888

Background Extracellular vesicles (EVs) play a critical role in intercellular communication under physiological and pathological conditions, including cancer. EVs cargo reflects their cell of origin, suggesting their utility as biomarkers. EVs are detected in several biofluids, and their ability to cross the blood–brain barrier has highlighted their potential as prognostic and diagnostic biomarkers in gliomas, including glioblastoma (GBM). Studies have demonstrated the potential clinical utility of plasma‐derived EVs in glioma. However, little is known about the clinical utility of saliva‐derived EVs in GBM. Methods Small EVs were isolated from whole mouth saliva of GBM patients pre‐ and postoperatively. Isolation was performed using differential centrifugation and/or ultracentrifugation. EVs were characterized by concentration, size, morphology, and EVs cell‐surface protein markers. Protein cargo in EVs was profiled using mass spectrometry. Results There were no statistically significant differences in size and concentration of EVs derived from pre‐ and post GBM patients' saliva samples. A higher number of proteins were detected in preoperative samples compared to postoperative samples. The authors found four highly abundant proteins (aldolase A, 14‐3‐3 protein ε, enoyl CoA hydratase 1, and transmembrane protease serine 11B) in preoperative saliva samples from GBM patients with poor outcomes. Functional enrichment analysis of pre‐ and postoperative saliva samples showed significant enrichment of several pathways, including those related to the immune system, cell cycle and programmed cell death. Conclusions This study, for the first time, demonstrates the feasibility of isolating and characterizing small EVs from pre‐ and postoperative saliva samples from GBM patients. Preliminary findings encourage further large cohort validation studies on salivary small EVs to evaluate prognosis in GBM. The current study demonstrates the feasibility of isolation and characterization of small extracellular vesicles (EVs) from saliva samples of glioblastoma (GBM) patients. It also demonstrates that the proteome content of EVs revealed GBM‐related proteins, some already described in previous studies using GBM cell‐conditioned media and plasma of GBM patients. Preliminary findings encourage further studies on salivary small EVs as a source of noninvasive prognostic biomarkers to predict outcomes in patients with GBM.