Abstract 102: Ferrichrome suppresses pancreatic tumor growth via targeting TAMs and enhancing CD8+ T-cells infiltration
Authors: Chaib Mehdi , Hafeez Bilal Bin , Kumari Sonam , Sikander Mohammed , Mandil Hassan , Makowski Liza , Pingili Ajeeth Kumar , Hatami Elham , Shetty Advait , Nirnoy Dan , Yallapu Murali Mohan , Jaggi Meena , Chauhan Subhash 
Published: August 2019

Background: Pancreatic cancer (PanCa) is one of the most lethal malignancy with a very poor survival rate in patients due to inadequate treatment options. Accumulating evidences suggest that tumor associated macrophages (TAMs) and reduce infiltration of CD8+ T-cell population provide tumor suppressive environment leading to advanced growth and metastasis of PanCa. Thus, targeting TAMs and enhancing infiltration of CD8+ T-cells to the tumor site by non-toxic agents could be an effective therapeutic approach for the management of PanCa. In this study, we demonstrate that a novel probiotic-derived agent (ferrichrome) inhibits pancreatic tumor growth in syngeneic mouse model via modulating TAMs and increasing infiltration of CD8+ T-cells.

Methods: RAW264.7 cells, murine peritoneal macrophages, mouse pancreatic cancer cells (UN-KC-6141) were used for this study. Effect of ferrichrome on the expression of pro (IL-12, p40, iNOS, IL-6), anti-inflammatory cytokines (MRC1 and Arginase-1) and iron metabolism markers (ferritin and ferroportin) in macrophages and co-culture systems was analyzed by qPCR. Effect of ferrichrome on metastatic phenotypes of PanCa cells was analyzed in a co-culture model of RAW264.7 and UN-KC-6141 cells. Therapeutic efficacy of ferrichrome was determined in syngeneic mouse model. Tumor immune infiltrating cells were analyzed in excised tumors by FACS, double immunofluorescence and immunohistochemistry analyses.

Results: Ferrichrome treatment reversed the polarization of M2 macrophages towards the M1 phenotype as observed by increase expression of IL-12p40, iNOS, IL-6 and decrease expression of MRC1 and Arginase-1. Ferrichrome significantly (P&lt;0.01) reduced the RAW264.7 cells induced migration and invasive potential of UN-KC-6141 cells. We further investigated the molecular mechanisms of ferrichrome induced M1 macrophage phenotype. Our results revealed that ferrichrome-induced M1 polarization of macrophages via upregulation of iron-sequestration protein (ferritin) and downregulation of iron-export protein (ferroportin). Ferrichrome administration (50 µg) intratumorally for 5 days per week for 26 days significantly (P&lt;0.01) inhibited growth of xenograft tumors. We observed an increase of CD8+ T-cell and iNOS+F4/80+ macrophages infiltration and a decrease in the expression of CD163+ macrophages in resected tumors of ferrichrome treated mice.

Conclusion: Our results strongly suggest that ferrichrome inhibits the tumor growth of PanCa via targeting TAMs and enhancing CD8+ T-cell infiltration. Ferrichrome could be used alone or in combination with current therapeutic regimens for the treatment of advanced PanCa.

Citation Format: Mehdi Chaib, Bilal Bin Hafeez, Sonam Kumari, Mohammed Sikander, Hassan Mandil, Liza Makowski, Ajeeth Kumar Pingili, Elham Hatami, Advait Shetty, Dan Nirnoy, Murali Mohan Yallapu, Meena Jaggi, Subhash Chauhan. Ferrichrome suppresses pancreatic tumor growth via targeting TAMs and enhancing CD8+ T-cells infiltration [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 102.