Dipeptide gamma-d-Glu-d-Trp (thymodepressin) inhibits migration of CD34+ cells from the bone marrow into peripheral blood during tumor growth.

We studied the effect of dipeptide gamma-d-Glu-d-Trp (thymodepressin) on migration of CD34+ hemopoietic precursors and their direct adhesion to fibronectin in tumor-bearing mice on days 8, 11, 15, and 17 of tumor growth and on expression of CXCR-4 (CD184+) to SDF-1 and integrin beta1 (CD29+) by bone marrow cells. In tumor-bearing mice treated with gamma-d-Glu-d-Trp, the percent of CD34+ hemopoietic precursors in the peripheral blood considerably decreased throughout the observation period; the content of CD34+ hemopoietic precursors in the tumor tissue was 2-3-fold below the control against the background of increased content of CD34+ cells in the bone marrow. In animals treated with the peptide, the content of cells expressing CXCR-4 in the peripheral blood, bone marrow, and tumor tissue significantly decreased, while the percent of cells expressing integrin beta1 receptor (CD29+) in the bone marrow increased 2-fold, which was paralleled by an almost 2-fold increase in the percent of cells binding to fibronectin.

The effects of the EW dipeptide optical and chemical isomers on the CFU-S population in intact and irradiated mice.

The influence of Glu-Trp (EW) synthetic dipeptide isomers on hemopoietic progenitor cells and certain immune response reactions is determined by their optical and chemical properties. Thus, the all L-amino acid containing dipeptides L-Glu-L-Trp and L-gammaGlu-L-Trp have no effect on proliferation of committed and pluripotent CFU-S in intact bone marrow. The optical isomers of the Glu residue are an essential determinant of the EW dipeptide biological activity.