Aim
Extravascular vesicle (EV) proteome closely reflects the proteome of the cell of origin. Therefore, cancer cell-derived EV proteomic analysis could help in identifying cancer biomarkers. This study's goal was to investigate hypoxia-induced proteomic changes in EV released from hypoxic human isogenic non-metastatic colorectal cancer cells SW480 and metastatic colorectal cancer cells SW620. Materials and
Conclusion
Under hypoxia, colorectal cancer cells release EV that qualitatively and quantitatively change the surface proteome. In the future, the specific hypoxia-induced proteins could be developed as new biomarkers for non-invasive assessment of tumour hypoxia.
Methods
EV were characterized by western blot, transmission electron microscopy, proteomic analysis using liquid chromatography time-of-flight-mass spectrometry and quantified by an label-free intensity-based absolute quantitation (iBAQ) approach.
Results
A total of 16 proteins in hypoxic EV exceeded normoxic EV protein levels in SW480 EV. Of them, 15 were also found in EV of hypoxic SW620 cells. The expression levels of proteins differed quantitatively: iBAQ (log 10) scores of the levels of five proteins in SW620 EV exceeded those in hypoxic SW480 EV and levels of 11 proteins in SW480 EV exceeded those of SW620 EV.