Tumor-Associated Macrophages Promote Invasion And Metastasis Of Colorectal Cancer Through Galectin-1-integrinβ1-MYO1B Pathway

Tumor Microenvironment(TME)plays an important role in tumor progression.TME is a complex tissue environment,including extracellular matrix(ECM)and various types of stromal cells,such as macrophages,tumor-associated macrophages(TAM),inflammatory cells,cancer Related fibroblasts(Cancer Associated Fibroblast,CAF)and mesenchymal stem cells(Mesenchymal Stem Cells,MSCs)[1]-[5].The main reason for the high mortality of colorectal cancer(CRC)is still caused by metastasis.TAM is highly heterogeneous and is closely related to tumorigenesis,metastasis and treatment of various cancer types.However,the function and clinical significance of TAM in CRC are highly controversial.In this study,in order to isolate different groups of macrophages in CRC,we chose CD68 as the general marker of TAM,CD 11c,NOS2,CXCL10 as M1 type molecular markers,and CD 163,CD206,CD115 as M2 type molecules Mark.We used immunohistochemistry(IHC)staining and double immunofluorescence staining on paraffin sections of CRC tissue specimens to detect CD68,M1 type molecular markers and M2 type molecular markers,respectively,and analyzed their expressions and patients’ gender,age,The relationship between tumor size,degree of differentiation,depth of invasion,lymph node metastasis,distant metastasis and other clinical parameters.At the same time,their expression and overall survival rate of CRC patients were analyzed by survival analysis,and verified by data in a public database(Gene Expression Omnibus,GEO),and the same conclusion was also obtained.We found that the detection of CD68 or M1 or M2 single molecular markers does not reflect the clinicopathological characteristics of patients well.Then we found through analysis that there is a correlation between M1 type molecular markers(NOS2,CD11c,CXCL10)or M2 type molecular markers(CD163,CD206,CD115).The combination of the three indicators of any type of molecular marker can be better The prognosis and survival rate of patients were evaluated,and it was found that the low expression of M1 type molecular markers and the high expression of M2 type molecular markers are related to tumor invasion.In the previous study of this research group,the cytokine chip was used to find the differential factor Galectin-1 in TAM at the frontier of tumor infiltration.In vivo experiments in mice further confirmed that Galectin-1 can enhance the CRC invasion ability.Double immunofluorescence staining,Co-Immunoprecipitation(Co-IP),Transwell and other technologies were used to verify that Galectin-1 interacted with MYO1B through its membrane receptor integral1 and then interacted with MYO1B,which caused an increase in MYO1B expression.Experiments in mice have verified that MYO1B promotes tumor invasion to local blood vessels in vivo,and MYO1B can promote metastasis in vivo.The relationship between the expression of Galectin-1 and MYO1B and the overall survival rate of CRC patients was analyzed by public bioinformatics.The results showed that the overall survival time of patients with positive expression of Galectin-1 and MYO1B was the shortest,and the total survival time of CD163,Galectin-1 and MYO1B was the shortest.The expression is similar.Conclusion:Galectin-1 and MYO1B expression are positively correlated.Next,we focused on the mechanism of Galectin-1 secreted by TAM in CRC through MYO1B to promote invasion and metastasis.We found that TAM promotes epithelial-mesenchymal transition(EMT)in CRC through Galectin-1-MYO1B through methods such as IHC,cellular immunofluorescence staining,and Western-blotting,and promotes CRC by activating the MYO1B/RACK1 signaling pathway EMT and induced cell pseudopod formation to promote CRC invasion and metastasis.In summary,we found that TAM accumulating at the frontier of tumor invasion initiates the invasion and migration of aggressive frontier tumor cells through the paracrine Galectin-l-integrinβ1-MYO1B pathway,leading to tumor metastasis and poor patient survival.Our findings clarify that targeting the Galectin-1-integrinβ1-MYO1B pathway may represent a new therapeutic strategy for CRC.