OBJECTIVETo examine whether the enhanced expression of CD40L cDNA on murine ovarian cancer (OVHM) cells could induce the secretion of Th1 cytokines from dendritic cells (DC).

METHODSOVHM cells were transfected with the full-length mouse CD40L cDNA by lipofectamine 2000 and then G418 resistant cells as positive cells were selected. They were examined for their expression of CD40L with flow cytometry. Bone marrow cells were firstly depleted of erythrocytes, macrophages, T and B cells with PE-conjugated magnetic beads, and then cultured in 10% FCS RPMI 1640 medium supplemented with recombinant mouse GM-CSF and IL-4 for 10 days. PKH67-labeled tumor cells were cultured with DC, and then the stained cells were analyzed for the expression of MHC-I, MHC-II, CD80, CD86, CCR7 in DC with flow cytometry. The expression of p40, p19, p35, p28, EBI3 subunits, IL-18, IFN-gamma, Mig gene in cocultured DC-tumor cells were detected by RT-PCR.

RESULTSThe CD40L cDNA was successfully transfected into OVHM cells. Bone marrow-derived DCs, when cultured with CD40L/OVHM, formed clusters with the tumors and showed an upregulated expression of MHC- I, MHC-II, CD80, CD86, CCR7. Expression of the IL-12, IL-23, IL-27, IL-18, interferon-gamma (IFN-gamma) and Mig (monokine induced by IFN-gamma) genes was induced in the DCs that were cultured with CD40L/OVHM but not with OVHM cells.

CONCLUSIONThese data directly showed that the expression of CD40L on ovarian cancer cells facilitates the interaction between DCs and tumors, enhances the maturation of DCs, induces secretion of Th1 cytokines, especially for IL-12, IL-23 and IL-27, which maybe one of the possible antitumor mechanism for CD40L-transfected ovarian cancer cell line.