Relation between Tetraspanin- Associated and Tetraspanin- Non- Associated Exosomal Proteases and Metabolic Syndrome in Colorectal Cancer Patients

Purpose: Exosomal proteases are important in regulation of molecular signaling from growth factor receptors andadhesion molecules and also the regulation of cell motility and protein folding. The aim of this study was to evaluatethe level of ADAM10, ADAM17 and 20S proteasomes in exosomes isolated from colorectal cancer patients (CRCPs)in relation with clinical and histopathological parameters. Methods: Blood plasma exosomes of 60 CRCPs at stageT2-4N0-2M0-1 and 10 control subjects (CSs) with colorectal polyps were isolated using ultrafiltration in combinationwith ultracentrifugation. The level of tetraspanin-associated (ADAM20 and ADAM17) and tetraspanin-non-associated(20S proteasome) proteases were evaluated by flow cytometry and western blot analysis. Results: The ADAM10-/ADAM17- population predominated in plasma exosomes of CRCPs and the level of ADAM10+ exosomes wassignificantly higher in exosomes of CSs compared with CRCPs. No difference was found between subpopulationsof ADAM10/ADAM17 exosomes and level of exosomal 20S proteasomes in terms of sex, age and tumor grade.Simultaneous decrease of ADAM10+/ADAM17-subpopulation of exosomes and level of exosomal 20S proteasomes inpatients with metastatic CRC was observed compared with patients with non-metastatic CRC. The level of ADAM17+exosomes significantly reduced in exosomes of CRCPs with metabolic syndrome compared to CRCPs withoutmetabolic syndrome( 3.97±0.71 (%) vs. 13.04±1.34 (%), respectively (p<0.05). A decrease in the 20S proteasomeslevel in plasma exosomes was revealed in CRCPs with metabolic syndrome compared with CRCPs without metabolicdisorders ( 1.90±0.25 (r.u.) vs. 2.92±0.42 (r.u.) respectively( (p<0.05). Conclusion: According to findings of this study,it seems that exosomal proteases can be promising molecular predictors of hematogenous metastasis in patients withnon-metastatic CRC. Further studies on subpopulation composition of exosomes CRCPs are need for elucidating therole of tetraspanin-associated and tetraspanin-non-associated exosomal proteases in CRC development and progression.