Tumor Associated Macrophages Downregulate MicroRNA-195-5p Through Targeting MAGE In Tumor Microenvironment Of Colorectal Cancer

Background:There are lots of evidents to illuminate that M2 macrophage is elevated in the tumor microenvironment(TME). In cancer, tumor-associated macrophages(TAMs) are recruited to the tumor stroma in response to cytokines secreted by tumor cells, and are believed to facilitate tumor cell invasion and metastasis.In this study, we focused on immune cells in TME to present the effect of M2 macrophages in colon tumor stroma and the mechanism of microRNA-195 as well as its target gene-MAGE in this process.First,a co-culture system was established to make a transformation from THP-1 to M2 macrophages with the help of culture medium extracted from colon cancer cell(loVo cell line),ELISA and Flow cymetry was performed to testify M2 macrophage’s phenotype of transformed THP-1 cells, then miR-195 in M2 macrophages were extracted and tested by RT-PCR and western blot to demonstrate that mi R-195 was elevated, meanwhile its target protein was down-regulated, next, transwell test showed that after the transfection with miR-195 mimics and miR-195 inhibitor to loVo cells co-cultured with TAMs,the loVo cells were performed a decreased invasion ability and an increased invasion ability respectively,compared with non-transfection group(NC group).Colorectal cancer(CRC) is one of the leading cause of cancer deaths worldwide.in recent years, as people’s living standard are elevated and a change of the diet, there is an upward trend in the incidence of the disease. Early diagnosis of colon cancer are still difficult,as most diagnosed patients are already have distant metastasis. Nowadays, the influence of the tumor microenvironment become to be a new research hotspot, and tumor associated macrophage(tumor associated macrophage, TAM) as an important component of the tumor microenvironment,exhibit an irreplaceable role in the malignant tumor’s occurrence, development and metastasis.Tumor associated macrophages located in tumor stroma, it can produce cytokines or directly regulate relevant gene and the target protein of the tumor cells,make change of tumor growth, proliferation, invasion and metastasis as well as influence its biological characteristics. Previous studies found that tumor associated macrophage are closely related with most cancers. At the same time, its infiltration degree is negatively correlated with the prognosis of patients with tumours. This research make an establishment of the co-culture system and detect the change of miRNA- 195-5p, explore the tumor associated macrophage’s impact on colon cancer biology behavior. Purpose 1.The co-culture model is set up to verify the components of the co-culture system are M2 macrophages. 2. Downregulated of microRNA- 195-5p in M2 macrophages,followed by an increase in MAGE expression, they finally affect the biological characteristics of colon cancer.