Expression of mTGF-β1 on the surface of exosomes in plasma from patients with colorectal cancer and its biological function

JU Songwen

doi:10.3969/j.issn.1002-266X.2016.44.001

Abstract：Objective To explore the membrane-bound transforming growth factor-β1 ( mTGF-β1 ) expression on the surface of exosomes in the plasma from patients with colorectal cancer and its biological function .Methods The expression of mTGF-β1 on the surface of exosomes from 20 samples of patients with colorectal cancer ( observation group ) and 10 healthy donors (control group) were analyzed by flow cytometry.Peripheral blood mononuclear cells (PBMCs) were isolated from heparin anticoagulated whole blood of colon cancer patients , and CD4+T cells were purified and obtained by sorting .Mean-while, CD3 and CD28 were used to induce cell proliferation , and the cells were randomly divided into three groups:groups A, B and C, group A was added with 1μg/ml exosomes from plasma of patients treated with anti-TGF-β1 monoclonal anti-body ( mAb) , group B was added with 1μg/ml exosomes from plasma of patients treated with control IgG 1 mAb and group C was added with 1μg/mL exosomes from plasma of healthy donors .The cell count was calculated by Trypan blue stainin , and the levels of TNF-αand IFN-γwas detected by ELISA on day 3 after culture.Results The positive rate of mTGF-β1 expres-sion in the observation group was 36.52%±4.26%, which was higher than that (9.23%±3.77%) in the control group (P<0.01).Compared with group C, the number of CD4+T cells and the levels of TNF-αand IFN-γsecreted in the group B were all lower than those in the group C (all P<0.05).Compared with group B, the number of CD4+T cells and the levels of TNF-αand IFN-γsecreted in the group A were higher (all P<0.05).Conclusion The mTGF-β1 expression is highly expressed on the surface of exosomes in the plasma from patients with colorectal cancer , and the increased expression of mT-GF-β1 may play an important role in the colon cancer immunosuppressive environment , which promotes the occurrence and development of colon cancer .