IMMU-66. A NOVEL METABOLITE TO INCREASE EFFICACY OF CELLULAR IMMUNOTHERAPY IN THE TREATMENT OF GLIOBLASTOMA Free

Immune cell migration is critical for cellular immunotherapy efficacy in the treatment of glioblastoma (GBM). Sarcosine is a non-toxic metabolite that is associated with a migratory phenotype in prostate cancer cells. We utilized sarcosine to increase migration of dendritic cells (DC) and T cells to increase efficacy of cellular immunotherapy. HYPOTHESIS: Sarcosine increases cellular migration and will improve tumor outcomes when combined with cellular immunotherapy platforms in the treatment of GBM.

DC and T cell migration was evaluated in vitro using transwell plates and in vivo using flowcytometry and immunofluorescence microscopy. The impact of sarcosine loaded cells on tumor outcomes was measured by testing a DC vaccine platform in the treatment of murine tumor models. Genomic expression of cytokines on sarcosine treated cells was tested using RT-PCR.

Cells were efficiently loaded with sarcosine by simply adding sarcosine to the culture media (20mM). DCs and T cells loaded with sarcosine demonstrated increased migration in vitro (p<0.0001). Mice treated with DC vaccination in the setting of sarcosine demonstrated significantly increased DC migration to draining lymph nodes and spleens (p<0.05). Gene expression analysis demonstrated that sarcosine caused upregulation of cytokines (IFNg,Xcl1,Fasl,Csf2,CCL19,Bmp2,IFNa2 and IL27) and downregulation of other cytokines (Ccl22,IL1b,Cxcl3,Ccl5,IL9 and IL18)(p<0.05). Vaccination with sarcosine loaded OVA-DCs led to increased proliferation of antigen specific T cells compared to regular OVA-DC vaccination (p<0.05). B16F10-OVA tumor bearing animals treated with sarcosine loaded OVA-DC vaccines had significantly reduced tumor growth and prolonged survival compared to animals treated with OVA-DC vaccines without sarcosine (p<0.0001).

Sarcosine loaded DC vaccines resulted in suppressed tumor growth and improved survival in a murine model. These effects are partially mediated by changes in cytokine expression in sarcosine loaded DCs. Further experiments testing sarcosine loaded T cells and the mechanism of increased migration in sarcosine loaded immune cells are underway.