Abstract 388P
Background
Pancreatic cancer (PC) is associated with rapid progression and a lack of efficient biomarkers. Recently, small extracellular vesicles (sEV) have gained attention in diagnosis and prognosis. The analysis of PC-specific sEV from circulation could be a practical approach for early diagnosis of this disease; however, unique surface markers required for such isolation of PC-specific EVs are currently unknown.
Methods
For the present study, we utilized 12 PC patients’ tissue samples along with matched tissues from healthy regions of the pancreas. Following our well optimized methods, we isolated sEV from these tissues by sucrose cushion based ultracentrifugation method, measured their size and concentration by nanoparticle tracking analysis (NTA), shaved sEV surface and separated surface and core proteins and analyzed those by LC-MS/MS. The surface and core proteins, with peptide spectrum count of >2 and presence in at least 75% of the samples, were analyzed.
Results
NTA revealed 6.8-fold (p=0.0007) higher sEV concentration (number/ml/mg tissue) in PC compared to healthy tissues. Similarly, we consistently observed higher number of surface and core proteins in sEV from PC group. We identified 282 proteins on the surface of sEV from healthy tissues and 463 proteins on sEV from PC tissues; 234 proteins were common between the two groups. All these proteins were queried in Human Protein Atlas leading to identification of prolyl 4-hydroxylase subunit beta (P4HB) and annexin A4 (ANXA4) as pancreas specific sEV surface markers, which could be used to isolate pancreas specific sEV from peripheral circulation. Similar analyses of core proteins showed 170 proteins loaded in sEV from healthy tissues and 252 proteins loaded in sEV from PC tissues. Importantly, human protein analyses helped us identifying glycoprotein 2 (GP2), endosome-lysosome associated apoptosis and autophagy regulator 1 (ELAPOR1), and peroxiredoxin 4 (PRDX4) as PC specific sEV proteins.
Conclusions
Overall, results from the present study offer a unique approach to isolating PC-specific sEV from biofluids and unique PC-specific sEV protein biomarkers, which could be helpful in early diagnosis and better molecular characterization of this disease.
Legal entity responsible for the study
The authors.
Funding
Atrium Health Wake Forest Baptist.
Disclosure
R.K. Paluri: Financial Interests, Personal, Speaker’s Bureau: Ipsen, Seagen; Financial Interests, Personal, Advisory Board: Exelixis. All other authors have declared no conflicts of interest.