serum exosomes of right-sided colon cancer promote metastasis via overexpression of SPARC and LRG1

Purpose: Over the past few years, the distinction between left- and right-sided colon cancer has been brought into focus. Right-sided tumor location was associated with an inferior overall survival and progression-free survival. We aimed to perform a detailed analysis of the diversity in exosomes between left- and right-sided colon cancer using quantitative proteomics. Experimental Design: We isolated exosomes from left- and right-sided colon cancer patients and healthy volunteers and treated colorectal cancer cell line with serum-derived exosomes. Then we performed quantitative proteomics analysis of the serum-derived exosomes and cell line treated with exosomes, respectively. Results: The expression profile of the serum exosome proteome in patients with right-sided colon cancer is different from patients with left-sided colon cancer. Serum-derived exosomes of right-sided colon cancer promote metastasis via up-regulation of extracellular matrix-related proteins, especially proteoglycans like SPARC and glycoprotein like LRG1. Exosomal SPARC and LRG1 were closely correlated with progression-free survival. Conclusions: Proteomic analysis identified different exosomal protein profiling between left- and right-sided colon cancer. Serum-derived exosomes of right-sided colon cancer promote metastasis via overexpression of SPARC and LRG1.