The Association Between Tumor Associated Macrophage (TAM) Heterogeneity And Tumor Heterogeneity

Background and ObjectsMacrophages can differentiate into two different types:M1 macrophages can protect us from pathogens and tumor,while M2 macrophages can promote tumor growth and metastasis.The latter one can be distinguished by CD68 and CD206 through flow cytometry or immunohistochemistry.What's more,M2 can be differentiated into several subgroups by their cell surface markers and the cytokines they secrete.Recently,several experiments have proved that there are plenty of macrophages,also called tumor-associated macrophages(TAMs),in tumor microenvironment.The cell surface markers of TAMs are more similar to M2 types.There are researches shows that tumor cells can induce macrophages polarizing into M2 type macrophages.What's more,cytokines such as IL-6,LIF and IFN-y may play an important role in this procedure.Tumor heterogeneity has always been a vital subject in tumor research.However,apart from the heterogeneity of tumor cells,do TAMs also have heterogeneity?And what's the association between tumor heterogeneity and TAMs heterogeneity in ovarian cancer?In this experiment,we cultured different types of ovarian cancers with macrophages(differentiated from THP-1)to find the association between tumor heterogeneity and TAM heterogeneity.Methods1.Ovarian cancer cells were cultured with macrophages differentiated from THP-1 through transwells,in order to prevent their direct interaction.After co-culture for a period of time,the macrophages polarized into different groups.2.Analyze the subtypes of macrophages using flow cytometry.Compare the M2 ratio in macrophages between different groups,and the ration changing over time.3.Detect the concentrate of several cytokines of the supernatant secreted by different macrophages induced by different ovarian cancers using ELISA.4.Ovarian cancer A2780 cells were cultured with different macrophages induced by different ovarian cancers in step 1.Then detect the concentrate of several cytokines secreted by these A2780 cells.What's more,detect their growth rate with CCK8.Results1.The M2 ratio in different macrophage groups induced by different ovarian cancers was significantly different,and the ratio changing over time was also different between these groups.The M2 ratio of MA2780 and MSKOV3 kept high over time;in the contrast,the M2 ratio in MIGROV1 decreased with co-culture time extending;M2 ratio in MES2 increased at first and then fell down after co-culture for 72 hours.2.The M2 cells induced by different tumors were also different in cytokine secreting.What's more,the tumor growth promoting ability also differed between different M2 cells induced by different ovarian tumors.3.The growth rate of different groups of A2780 co-cultured with different macrophages for 72 hours were associated with average concentration of IL-10,which means that IL-10 may play an important role in the tumor growth rate changing.4.The macrophages induced by HOSEpiC were more or like macrophages induced by ovarian cancers.If we compare the genome differences between HOSEpiC and normal ovarian epithelial cells,we may find some important genes affecting the macrophage differentiation.ConclusionsDifferent ovarian cancers have different ability of inducing macrophages into M2.The differences not only exist between clear cell tumor and adenocarcinoma,but also between adenocarcinoma from different sources.Besides,the M2 cells induced by different ovarian cancers are also different in cytokines secreting and the ability of promoting tumor growth.The macrophage heterogeneity is a reflection of tumor heterogeneity.