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Enhancement of Dendritic Cell Functions: 3-D Models of Tumor Suppression.   V. Chopra1, E.V. Hannigan1, and C.A Savary2 1Dept. of Obstetrics and Gynecology, UTMB, Galveston, TX and Dept. of melanoma Medical Oncology, UT-MD Anderson Hospital, Houston, TX.

   DCs trafficking and function in cervical cancers is poorly characterized, with studies confined to myeloid DC (DC1) in human papilloma virus (HPV)-associated cervical intraepithelial neoplasias (CIN). The role of plasmacytoid DCs (DC2) in HPV-associated tumor immunity is unknown. Our results indicate that the 3-Dimensional (3-D, mimics the in vivo host microenvironment) cultures of HELA (HPV18+) cells in the NASA-designed bioreactors produce excess amounts of interleukin-10 (IL-10), vascular endothelial growth factor (VEGF) and stromal-derived factor-1 (SDF-1) in excess of conventional 2-Dimensional monolayer cultures. We have shown that high levels of VEGF and SDF-1 secreted by 3-D grown tumor cell aggregates induce DC2 precursor chemotaxis and adhesion, and protect DC2 from IL-10 induced apoptosis. The secreted factors also enhance transdifferentiation of DC cells into endothelial precursor phenotypes. The generation of CD1a+ cells was accompanied by changes in expression of pSTAT3, IL-8, IL-10, IL-12, TNF-a, and NO radicals. Phase contrast microscopy confirmed the formation of very large, nonadherent, and loose 3-D aggregates of developing CD1a+ cells (in presence of GM-CSF+IL-4) which consisted of Lin-HLA-DR+, Lin-B7-2+ (CD86+) and Lin-CD40+ cells. These plastic adherent cells cultured in the presence of conditioned medium from 3-D grown HELA were CD34+ (stains endothelial precursors and mature endothelial cells), and showed evidence of formation of tube and network-like structures by adherent cells after immunofluorescence staining. These cells were also PECAM-1+ (CD31+), and VCAM-1 (CD106+) and ICAM-1 (CD54+). The activation of DC2 thus contributes to poor T-cell activation and immune tolerance of tumors and also enhances the transformation of immune cells to endothelial phenotype.