The role of Sema3A in inflammation mediated tumor progressions

In the tumor microenvironment there are many different cell types present and among these, immune cells display a large proportion. Central players in the tumor immunity are macrophages that come in two different phenotypes, the M1 and M2 macrophages. M1 polarized macrophages are tumor suppressive while M2 polarized macrophages support tumor growth. The factors that contribute to the skewing of macrophages from one phenotype to another are under investigation. Interestingly, our lab has identified Immune Semaphorin 3A (Sema3A) as a participating plaer in regulating the accumulation of anti-tumoral M1 macrophages leading to a suppression of tumor growth. In light of these data this thesis has focused on the role of endogenous Sema3A in the tumor microenvironment. A tumor cell line expressing shRNA against Sema3A mRNA was generated using lentiviral mediated gene therapy. This knockdoen cell line showed 72% lower mRNA expression compared to control and was evaluated in vivo by monitoring tumor progression in female BALB/c mice. The immune cell composition of the tumors was analysed using flow cytometry. The results from the in vivo experiment show that endogenous Sema3A has a limited effect on tumor progression. A slight shift to a more tumor supportive immune profile was observed in the knockdown tumors. Moreover, a virus for transducing cells to overecpress Sema3A under asuitable promoter for systemic delivery was generated.