Oral Presentation Joint Scientific Meeting of the Australian & NZ Head & Neck Cancer Society & NZ Association of Plastic Surgeons

An ex vivo examination of oral cancer-derived exosomes (1362)

Mohammad Aziz 1 , Benedict Seo 1 , Haizal Mohd Hussaini 1 , Merilyn Hibma 2 , Alison M Rich 1
  1. Sir John Walsh Research Institute, University of Otago, Dunedin, Otago, New Zealand
  2. Pathology Department, University of Otago, Dunedin, Otago, New Zealand

Purpose: Exosomes are membrane bound nanovesicles released by cells into their extracellular environment. Their contents, including proteins and nucleic acids, can be transferred from one cell to another, including between cancer cells, leading to transcriptional and translational changes in the recipient cell. Salivary exosomes provide a potential pathway to detect oncogenes and oncoproteins in patients with various diseases, including oral squamous cell carcinoma (OSCC). They may provide a useful source for diagnosis and monitoring cancer progression. This study compared the mRNA levels of the genes of interest FOXM1, DNMT1, HOXA7, CCNB1 and HSPA1A and proteins of interest (POI) FOXM1, DNMT1, CCNB1 and HSP70 in exosomes derived from plasma and saliva of OSCC patients and healthy controls.

Methodology: Exosomes were isolated from plasma and saliva using ultracentrifugation, and their presence confirmed by Cryo-EM. The exosomal RNA and proteins were extracted and subjected to qPCR for mRNA analysis and ELISA for protein analysis.

Results and Conclusion: Cryo-EM revealed structures consistent with the expected size of exosomes, and exosomal surface protein markers were detected in all samples. Transcripts for HSPA1A only were detected with a higher expression in OSCC plasma (mean 2-ΔCT:0.68) and saliva (mean 2-ΔCT: 0.73) exosomes compared to controls. All the POI were detected in all samples with a higher expression of FOXM1, DNMT1 and CCNB1 in OSCC plasma exosomes and a higher expression of FOXM1 and DNMT1 in OSCC saliva exosomes compared to matched controls. Due to high variation between individual samples, the results were not statistically significant except for FOXM1 protein, which showed a significantly higher expression in OSCC plasma exosomes. The results provide the first evidence that there is more HSPA1A RNA and FOXM1 and DNMT1 protein in plasma and saliva OSCC exosomes than healthy controls.