The Study On Anticancer Mechanism Of Uncedylprodigiosin

Prodiginines are a large family of red antibiotic produced by several actinomycetes and other eubacteria including prodigiosin, prodigiosin 25-C, metacycloprodigiosin (MP), desmethoxyprodigiosi, uncedylprodigiosin (UP), Cycloprodigiosin (CPrG) et al. It has been found that UP has immunosuppressive properties, however, there are few studies on its anticancer activities.Preliminary screening found that UP could inhibit proliferation of many tumor cell lines, particulally,P388 cell.This paper will test the inhibitory activity of UP on P388,and explore its possible michanisms.Firstly, The effects of UP on the proliferation of murine leukemia cells-P388 is investigated by MTT assay.The result shows that UP can significantly inhibit the proliferation of P388,the IC50 is 42 nM. DNA contents are analyzed with flow cytometry, it is found that UP induces arrest at the G2/M phase and increases in the sub-G1 phase DNA contents.Meanwhile, UP can increase the expression of Cyclin B1 and cleave PARP; UP reduces mitochondrial membrane potential and activates Caspase-8,9,3.T hese results reveales that death receptor pathway and mitochondrial pathway are involved in apoptosis induced by UP in P388 cells.In order to futher elucidate the mechanisms underlying apoptosis induced by UP,firstly, the-location of UP in cell-is observed with laser scanning confocal microscope.PI-3K/AKT and MAPK signal pathways are studied,no distinct effect on AKT phosphorylation is found, but it can induce phosphorylation of P38, ERK and JNK remarkably. Selective inhibitor of P38 and JNK prevents the p388 cancer cells from injuring induced by UP treatment except for ERK.This is consistent with their effects on cell cycle arrest. UP increases incellular reactive oxygen species slighty, NAC can not reverse growth inhibition caused by UP. UP has similar effect on intracellular acidification. Imidazole reverse growth inhibition caused by UP slightly. Nagtive-PAGE isolates the proteins binding with UP, then analyse them by MS.951 proteins are detected among which 171 proteins are ribosome-related.Localize UP and ribosome with antibody of ribosomal protein L3.They have good cololization.The results indicate that UP inhibits proliferation of P388 by inducing apoptosis,apotosis induced by UP is related with the activation of MAPK and G2/M phase arrest,ribosome may be the target of UP in P388 cells. This paper provides theoritical basis for developing UP as an anti-cancer leader compound.