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Peptidoglycan is a universal component of bacterial walls that exerts various biological activities, including tumoricidal effect. Anti-cancer effect of various peptidoglycan fractions and their derivates is different. Muramyl pentapeptide (MPP) is the most complete building block of peptidoglycan. MPP can stimulate cell reactivity as well as other muropeptides. In the present study, we evaluated inhibitory MPP effect on viability and migration of glioblastoma cells U373MG. As markers of cell reactivity we determined the amounts of proteins PARP1 and NF-kB. MPP exposure induced decrease in viability and migration activity of glioblastoma cells. Besides, MPP treatment increased the amounts of PARP1 and NF-kB in a dose-dependent manner. Furthermore, NADH level in exposed glioblastoma cells was depleted as compared to control. Thus, MPP exhibits tumoricidal effect in glioblastoma cells U373MG via depletion NADH content and consequently metabolic energy level. Moreover, upregulation of the amounts of PARP1 and NF-kB in glioblastoma cells could be an important mechanism of the inhibition of cell migrative capability and the progress of the tumor. The obtained results evidenced that muramyl pentapeptide could initiate lack of migration via metabolic energy expenditure as a result of gliotypic reactivity. Further studies are actual and extremely required to clarify tumoricidal effect of this muropeptide in glia-derived tumors.

The article describes an NMR spectroscopy study of interactions between vancomycin and a muramyl pentapeptide in two complexes: vancomycin and a native muramyl pentapeptide ended with D-alanine (MPP-D-Ala), and vancomycin and a modified muramyl pentapeptide ended with D-serine (MPP-D-Ser). The measurements were made in a 9:1 mixture of H2O and D2O. The obtained results confirmed the presence of hydrogen bonds previously described in the literature. At the same time, thanks to the pentapeptide model used, we were able to prove the presence of two more hydrogen bonds formed by the side chain amino group of L-lysine and oxygen atoms from the vancomycin carboxyl and amide groups. This type of interaction has not been described before. The existence of these hydrogen bonds was confirmed by the 1H NMR and molecular modeling. The formation of these bonds incurs additional through-space interactions, visible in the NOESY spectrum, between the protons of the L-lysine amino group and a vancomycin-facing hydrogen atom in the benzylic position. The presence of such interactions was also confirmed by molecular dynamics trajectory analysis. [ABSTRACT FROM AUTHOR]