Diaminopimelic (DAP) acids, derived from bacterial peptidoglycans, have been used for the study of tumor progression. Ala-D-g-Glu-DAP (also known as Ala-D-g-Glu-meso-Dap or gTriDAP), where the Dap is coupled to the g-carboxylic acid of the D-isomer of Glu, is an activator of Nod1 cytosolic protein. The primary function of Nod1 is linked to the growth of estrogen-sensitive tumors and plays a role in host responses to invasive bacteria and apoptosis. The lack of Nod1 in cells correlates to tumor growth, increases sensitivity to estrogen-induced cell proliferation and causes failure to undergo Nod1-dependent apoptosis. Ala-a-Glu-meso-Diaminopimelic acid, also known as aTriDAP in which meso-diaminopimleic acid is bound to the D-isomer of Glu in the a position rather than the g position, does not stimulate cell apoptosis.
Ref: Da Silva Correia, J. et al. Proc. Natl. Acad. Sci. USA 103, 1840 (2006); Baum, EZ. et al. Antimicrobial Agents Chemo. 50, 230 (2006).