Dendritic cells (DCs) can determine whether or not robust cell-mediated immunity constitutes the appropriate response to antigenic challenge. Stem cell mobilizing treatments can be employed to proliferate and distribute DC precursors throughout the tumor-bearing host, but mobilization treatments such as FltSL+GMCSF have also been observed to promote immunosuppression and favor tumor progression. We recently identified that mouse bone marrow (BM) conditioning with FK3L+IL6 is an exceptionally promising strategy for DC mobilization. Flt3L+IL6 causes abundant proliferation of CD34pos stem cells, comparably to FltSL+GMCSF, but in contrast to FltSL+GMCSF, (1) FltSI+ILG conditioning preempts normal multilineage hematopoiesis in favor of nearly global DC differentiation;(2) it promotes uniform responsiveness to toll-like receptor (TLR) agonists, greatly facilitating DC1-type polarization and IL-12p70 secretion;(3) it licenses spontaneous DC maturation, bypassing normal requirements for signals such as CD40 ligand or toll-like receptor (TLR) agonists;(4) it confers resistance to tumor-associated immunosuppressants such as IL-10, TGF-(3, VEGF and PGE2;(5) it induces the capacity to respond to tumor contact itself with accelerated DC1 polarization, including IL-12 production. With these exceptional properties, Flt3L+IL6 conditioned DCs exposed to viable tumor cells also display a superior capacity to reverse tolerance and promote proliferation of therapeutically potent, tumor-specific T cells. Importantly, these favorable impacts of Flt3L+IL6 DC conditioning are completely abrogated if GM-CSF is also present during proliferative conditioning. This project's aims are: (1) to characterize the mechanisms which render FU3L+IL6 conditioned mouse DCs therapeutically superior, so that the same properties can be elicited in human DCs;(2) to characterize and optimize the therapeutic impacts of Flt3L+IL6 mobilization in tumor-bearing mice, with formal comparisons of rlL6 to the potent designer cytokine hyperlLG;(3) to compare the function, including TLR expression, of human monocyte-derived DCs with human CD34pos BM cells after the latter have been proliferatively conditioned with Flt3L+IL6 vs FltSL+GMCSF. Lay summary: Dendritic cells (DCs) are the body's best cell for educating the immune system to recognize and destroy cancer. We have identified that a particular treatment, FltSL plus IL6, results in superior activation of DCs, which we hope will provide a more effective treatment against cancer. This project aims to provide the information needed to bring this research to a clinical trial for treating cancer patients.
|Finke, James H; Rayman, Pat A; Ko, Jennifer S et al. (2013) Modification of the tumor microenvironment as a novel target of renal cell carcinoma therapeutics. Cancer J 19:353-64|
|Cohen, Peter A; Ko, Jennifer S; Storkus, Walter J et al. (2012) Myeloid-derived suppressor cells adhere to physiologic STAT3- vs STAT5-dependent hematopoietic programming, establishing diverse tumor-mediated mechanisms of immunologic escape. Immunol Invest 41:680-710|
|Ko, Jennifer S; Rayman, Patricia; Ireland, Joanna et al. (2010) Direct and differential suppression of myeloid-derived suppressor cell subsets by sunitinib is compartmentally constrained. Cancer Res 70:3526-36|
|Cohen, Peter A; Koski, Gary K; Czerniecki, Brian J et al. (2008) STAT3- and STAT5-dependent pathways competitively regulate the pan-differentiation of CD34pos cells into tumor-competent dendritic cells. Blood 112:1832-43|
|Zheng, Rongxiu; Cohen, Peter A; Paustian, Christopher A et al. (2008) Paired Toll-like receptor agonists enhance vaccine therapy through induction of interleukin-12. Cancer Res 68:4045-9|