ABSTRACT
Previous studies suggest that NGAL (neutro phil gelatinase-associated lipocalin) is involved in the transformation and development of esophageal carcinoma. Alteration of NGAL expression can trigger the change of cellular morphology in esophageal carcinoma cells. However, the mechanisms remain unclear. To get a better understanding of NGAL function in esophageal carcinoma, NGAL protein was expressed in methylotrophic yeast, Pichia pastoris, and purified by chromatography. EC1.71 cells expressed high levels of NGALR (NGAL receptor) and EC109 cells expressed low levels of NGALR were used as cells model. The trafficking and the possible function of NGAL protein were then analyzed in the esophageal carcinoma cells. The results showed that 5-FAM-labeled recombinant NGAL protein could internalize into the EC1.71 and EC109 cells. Furthermore, the internalized NGAL protein could induce the alteration of cellular morphology, resulting in generation of autophagosome, transcriptional up-regulation of genes associated with autophagy and increase of phospho-ERK1/2 (p-ERK1/2). Interestingly, the treatment with the NGAL protein did not affect the intracellular iron level. These data indicate that induced autophagy by exogenous NGAL protein is a mechanism that internalized NGAL plays important roles in esophageal carcinoma cells, independent with NGAL-mediated iron transport process, while ERK1/2 signal pathway is involved in activation of autophagy by exogenous NGAL protein.
ABSTRACT
Background and purpose:Tumor necrosis factor-related apoptosis inducing ligand(TRAIL)is a successful clinical anti-tumor agent.However,not all tumor cells are sensitive to TRAIL-mediated apoptosis.In this study,we examined the TRAIL-induced apoptosis after pretreatment with pentamidine in K562 cells.Methods:When K562 cells were pretreated with pentamidine followed by TRAIL,apoptosis of cells was analyzed by cellular morphology via viewing live cells under a light microscope and annexin V-FITC/propidium iodine FACS.Western blot was performed to examine the cleavage of caspase-3,-8 and poly(ADP-ribose)polymerase(PARR)and protein levels of X-linked inhibitor of apoptosis protein(XIAP).Results:Apoptotic cell death occurred and cleavage of caspase-3,-8 and PARR appeared when K562 cells were pretreated with 10?g/ml of pentamidine followed by 200 ng/ml of TRAIL.In addition,pentamidine decreased protein levels of XIAP.Conclusions:Combined treatment with pentamidine and TRAIL may become a new strategy for cancer therapy.
ABSTRACT
Aim To investigate the effect of matrine on cytoskeletonof K562 cells. Methods Micropipette aspiration technique was adoptedto investigate the viscoelasticity of K562 cells, while the different ex-pression of cytoskeletal protein gene was analyzed by DNA microar-ray. Results In matrine-treated K562 cells, the viscoelastic propertiesKI, K2 and were decreased significantly from 726 ± 215 to 432 ±67,433 ±119 to 242±31, 72±38 to 50±15 respectively, and the geneexpression of prefoldin and ezrin was much stronger than that of controlcells. Conclusion The strueture and function can be changed in ma-trine-treated K562 cells.
ABSTRACT
Objective To investigate inhibitory effects of matrine (Ma) combined with vincristine (VCR), cytosine arabinoside (Ara-c), harringtonine (HRT), adriamycin (ADM), and daunorubicin (DNR) on proliferation of K562 cells. Methods MTT colorimetric assay was used to detect the inhibition rate of Ma combined with antineoplastic on K562 cells. Results The proliferation of K562 cells was inhibited by Ma at the concentration of 160 ?g/ml to 400 ?g/ml. The inhibitory rates of Ma combined respectively with VCR, Ara-c, HRT, ADM, and DNR were significantly higher than those of VCR, Ara-c, or HRT alone (P0.05). Conclusion Ma can inhibit the proliferation of K562 cells in a dose-dependent manner. The anti-proliferation effect of VCR, Ara-c, and HRT on K562 cells could be enhanced by Ma.