Many types of tumor cells overexpress transforming growth factor beta (TGF-beta), which is believed to promote tumor progression. We hypothesized that overexpression of the extracellular region of the type II TGF-beta receptor (soluble TbetaRII) would compete for or block TGF-beta binding to TbetaRs on immune cells, preventing TGF-beta-mediated immunosuppression and consequently resulting in th...

Many types of tumor cells overexpress transforming growth factor b (TGF-b), which is believed to promote tumor progression. We hypothesized that overexpression of the extracellular region of the type II TGF-b receptor (soluble TbRII) would compete for or block TGF-b binding to TbRs on immune cells, preventing TGF-b-mediated immunosuppression and consequently resulting in the eradication of tumo...

For T cells to become functionally activated they require at least two signals. The B7 costimulatory molecules B7-1 and B7-2 provide the "second signal" pivotal for T cell activation. In this report, we studied the relative roles of B7-1 and B7-2 molecules in the induction of antitumor immunity to the T cell thymoma, EL4. We generated EL4 tumor cells that expressed B7-1, B7-2, and B7-1+B7-2 by ...

BACKGROUND A blockade of CD44 is considered a therapeutic option for the elimination of leukemia initiating cells. However, anti-panCD44 can interfere with hematopoiesis. Therefore we explored, whether a CD44 variant isoform (CD44v)-specific antibody can inhibit leukemia growth without attacking hematopoiesis. As a model we used CD44v10 transfected EL4 thymoma cells (EL4-v10). METHODS The the...

The effect of thymidine (dlhd) on the growth of EL4 thymoma tumors in syngeneic C57BL/6 mice was determined. In vitro, EL4 cells are approximately 10-fold more sensitive to dlhd than are many other tumor lines, and they are 100-fold more sensitive than are normal cells; dThd (2.5 to 5 @g/ml)were cytostatic, and dlhd (12.5 to 25 pg/mI) cytotoxic to EL4 cells. The half-life of dlhd in mouse serum...

In order to investigate whether calcium signals participate in paraoxon (POX)-induced apoptosis in EL4 cells, real-time laser scanning confocal microscopy (LSCM) was used to detect Ca(2+) changes during the POX application. Apoptotic rates of EL4 cells and caspase-12 expression were also evaluated. POX (1-10nM) increased intracellular calcium concentration ([Ca(2+)]i) in EL4 cells in a dose-dep...

Tumor- or cancer-associated fibroblasts (TAFs or CAFs) from different tumors exhibit distinct angiogenic and tumorigenic properties. Unlike normal skin fibroblasts or TAFs from TIB6 tumors that are sensitive to anti-VEGF treatment (TAF-TIB6), TAFs from resistant EL4 tumors (TAF-EL4) can stimulate TIB6 tumor growth even when VEGF is inhibited. We show that platelet-derived growth factor C (PDGF-...

PURPOSE To investigate the potential of the La-specific monoclonal antibody (mAb) 3B9 as an in vivo tumor-targeting agent. EXPERIMENTAL DESIGN The murine EL4 lymphoma cell line was used for in vitro studies and the EL4 model in which apoptosis was induced with cyclophosphamide and etoposide was used for in vivo studies. In vitro studies compared 3B9 binding in the EL4 cell with that in its co...