PROLIFERATIVE CONDITIONING OF TUMOR-COMPETENT DENDRITIC CELL PRECURSORS

Project: Research project

Description

DESCRIPTION (provided by applicant): 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.
StatusFinished
Effective start/end date7/23/075/31/11

Funding

  • National Institutes of Health: $161,745.00
  • National Institutes of Health: $293,550.00
  • National Institutes of Health: $131,805.00
  • National Institutes of Health: $304,000.00
  • National Institutes of Health: $304,000.00

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Dendritic Cells
Interleukin-6
Neoplasms
Toll-Like Receptors
Stem Cells
Therapeutics
CD40 Ligand
Hematopoiesis
Licensure
Interleukin-12
Granulocyte-Macrophage Colony-Stimulating Factor
Immunosuppressive Agents
Dinoprostone
Cellular Immunity
Bone Marrow Cells
Interleukin-10
Immunosuppression
Vascular Endothelial Growth Factor A
Monocytes
Cell Differentiation

ASJC

  • Medicine(all)