ABSTRACT
This study was aimed to explore the potential therapy of Gambogic acid (GA) combined with magnetic nanoparticle of Fe3O4 (Fe3O4-MNP) on leukemia. The proliferation of U937 cells and the cytotoxicity were evaluated by MTT assay. Cell apoptosis was observed and analyzed by microscopy and flow cytometry respectively. The expressions of gene and protein were detected by quantitative real-time polymerase chain reaction and Western blot respectively. The results showed that GA enhanced the cytotoxicity for U937 cells in dose- and time-dependent manners. The Fe3O4-MNP itself had not cytotoxicity, but could enhance the inhibitory effect of GA on proliferation of U937 cells. The apoptotic rate of U937 cells induced by combination of GA with Fe3O4-MNP was higher than that by GA alone. The typical apoptotic features of cells treated with GA and Fe3O4-MNP were observed. The expression levels of caspase-3 and bax after co-treatment of GA and Fe3O4-MNP were higher than that exposed to GA or Fe3O4-MNP alone, but the expressions of bcl-2, NF-kappaB and survivin were down-regulated. It is concluded that Fe3O4-MNP can promote GA-induced apoptosis in U937 cells, and the combination of GA with Fe3O4-MNP may be a safer and less toxic new therapy for leukemia.
Subject(s)
Humans , Apoptosis , Iron Compounds , Pharmacology , Magnetics , Nanoparticles , U937 Cells , Xanthones , PharmacologyABSTRACT
This study was purposed to investigate the reversal effect of glucosylceramide synthase (GCS) inhibitor D, L-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) hydrochloride, on multidrug resistance in K562/A02 cells and its mechanism. The IC(50) (the half maximal inhibitory concentration) of PDMP was measured by MTT method. Cell apoptosis and intracellular daunorubicin (DNR) concentration were detected by flow cytometry. The expression of GCS and mdr1 genes were assayed by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot. The results showed that the IC(50) of DNR in K562 and K562/A02 cells were 0.23 +/- 0.02 and 7.15 +/- 0.24 microg/ml respectively. When the concentration of PDMP was equal to or less than 20 micromol/L ( < / = 20 micromol/L), the obviously inhibitory effect on proliferation of K562 and K562/A02 cells was not observed, but both 20 micromol/L and 10 micromol/L PDMP could enhance the sensitivity of K562/A02 cells to DNR (p < 0.01) and the reversal multiples were 2.59 and 1.69 respectively. After treating with 20 micromol/L and 10 micromol/L PDMP for 48 hours, the concentration of DNR in K562/A02 cells increased (p < 0.05) and the apoptotic rate also was elevated (p < 0.01). The expressions of GCS and mdr1 genes were down-regulated at mRNA and protein levels after treating K562/A02 cells with 20 micromol/L PDMP for 48 hours. It is concluded that PDMP can enhance the sensitivity of K562/A02 cells to DNR by increasing cell apoptosis rate and accumulation concentration of DNR in cells, which may be related to down-regulated expressions of GCS and mdr1 genes.
Subject(s)
Humans , Daunorubicin , Pharmacology , Drug Resistance, Multiple , Drug Resistance, Neoplasm , Enzyme Inhibitors , Pharmacology , Inhibitory Concentration 50 , K562 Cells , Morpholines , PharmacologyABSTRACT
Recent work indicates that an Aurora kinase inhibitor MK-0457 (VX-680), a small-molecule inhibitor of Aurora kinases A, B, C and BCR-ABL, FLT-3, JAK-2, can block the progression of cell growth cycle, causing apoptosis in a range of human tumors. MK-0457 has the activity against expressions of wild-type and mutated bcr-abl gene, including the T315I mutant, and can inhibit the activity of FLT-3, JAK-2 and their mutated types as well. Clinical applications suggest that the MK-0457 has therapeutic effect on the highly refractory CML and CML with poor prognosis, Ph(+) ALL with T315I mutant, relapse refractory AML and JAK-2 positive myeloproliferative diseases (MPD). The intensive preclinical studies and the on-going phase II clinical trials will open up a new vista of therapy for some hematological malignancies. This review focuses on the pharmacologic action of MK-0457 and its clinical trial as well as combined application.