The
biological features of
dendrimers are affected by the character of highly reactive terminal moieties. In some
polyamine dendrimer types the surface charge makes them bioincompatible and prevent their direct medical application. Moreover, foreign particles can induce the immune response which is undesirable due to the adverse side effects in vivo. The reduction of cytotoxicity of positively charged macromolecules is possible through chemical modifications of terminal groups. In our study, we have developed new derivatives of PAMAM
dendrimers modified with 4-carbomethoxypyrrolidone and evaluated their immunomodulatory properties. The experiments were conducted on two human
cancer myeloid cell lines: THP-1 and U937. To evaluate the cytotoxicity of
dendrimers, the reasazurin assay was applied. The expression level of NF-κB targets (NFKBIA, BTG2) and
cytokine genes (IL1B, TNF) was determined by quantitative real-time RT-PCR. The measurement of binding of NF-κB to a consensus
DNA probe was determined by electrophoretic mobility shift assay. The ELISA
cytokine assay was performed to measure
protein concentration of IL-1β and TNFα. We have found that PAMAM-
pyrrolidone dendrimers did not impact THP-1 and U937 viability even at high concentrations (up to 200 μM). The surface modification prevented PAMAM
dendrimers from stimulating NF-κB-related signal transduction, which have been determined on the level of nuclear translocation, gene expression and
protein secretion.
Pyrrolidone modification efficiently prevents PAMAM
dendrimers from stimulating pro-inflammatory response in human
cancer myeloid cell lines, thus it can be used to improve the biocompatibility of positively charged
dendrimers and to broaden the scope of their
biological applications.