Re-polarization Of Tumor-associated Macrophages To Pro-inflammatory M1Macrophages By MicroRNA-155

Macrophages are derived from monocytes, which are derived from the CD34+bone marrow precursor cells. They are involved in innate and acquired immunity by endocytosing pathogens, presenting antigen and activate other immune cells. The two polarized phenotypes of macrophage, classical activated pro-inflammatory Ml phenotype and alternative activated anti-inflammatory M2phenotype, vary greatly in cytokines, chemokines expression and other cell functions. Sometimes, they even antagonize with each other.Cancer has become one of the top3causes of death with the high mortality rate and increasing morbidity rate. Cancer is hard to cure due to its characteristic of metastasis. The mesenchymal cells, especially inflammatory cells, in tumor microenvironment helped tumor’s metastasis. The main cancer treatments aim at killing tumor itself without changing tumor microenvironment, and often do not lead to an ideal result.TAMs(Tumor Associated Macrophages), important inflammatory cells in tumor microenvironment, are considered to be related to poor prognosis of cancer. TAM is highly similar to M2phenotype. Its M2-like anti-inflammatory effects can help tumor metastasis.MicroRNAs, a kind of small single-stranded RNA containing approximately22 nucleotides, are coded from non-coding region of gene. They can regulate many genes’ expression at the post-transcriptional level. The specific microRNA expression changes in a variety of cancers reveal the connection between microRNA and tumor development. A research that tumor given missed microRNA became smaller or even disappeared gives a new thought of cancer treatment.In this subject, we found microRNA-155as a marker of macrophage polarization and the mechanism of polarization through experimental methods like low density array and qRT-PCR. On this basis, we successfully re-polarized macrophages by reversing the expression of microRNA-155. Through this method, we re-polarized TAM to pro-inflammatory M1macrophage. The re-polarized TAM can promote tumor cells’ apoptosis and inhibit their metastasis.