ABSTRACT
<p><b>OBJECTIVE</b>To explore the apoptosis resistance induced by Leptin and its mechanism in breast cancer cells in vitro.</p><p><b>METHODS</b>The leptin-mediated reduction of docetaxel-induced apoptosis in human breast cancer T47D cells was evaluated by TransAM ELISA, MTT and caspase-9 assay. The leptin-promoted survivin expression was analyzed by Western-blot and RT-PCR. The reversing effect of STAT3 knockdown on leptin-induced survivin upregulation was measured by Western-blot and RT-PCR.</p><p><b>RESULTS</b>Leptin promoted T47D cells proliferation and the inhibitory rate was -63.6%. It reduced docetaxel-induced apoptosis in T47D cells by 31.9%. Leptin at different concentrations promoted survivin protein and mRNA expression in T47D cells. The expression of survivin mRNA was 4.6 fold compared with the T47D cells not treated with leptin(10 nmol/L). The expression of survivin mRNA in T47D cells was 0.55 +/- 0.15 fold after transfected with small interfering RNA (siRNA) of STAT3. The expression of survivin mRNA in STAT3 siRNA group and mock transfected group were 0.56 +/- 0.18 fold and 1.61 +/- 0.22 fold after treated by leptin, respectively. The survivin protein level of T47D mock transfected cells was increased after treated by leptin, but the protein level of T47D transfected with STAT3 siRNA cells were not changed significantly.</p><p><b>CONCLUSION</b>Leptin/STAT3 signaling is a novel pathway for up-regulation of survivin expression in breast cancer cells.</p>
Subject(s)
Female , Humans , Apoptosis , Breast Neoplasms , Metabolism , Pathology , Cell Line, Tumor , Cell Proliferation , Inhibitor of Apoptosis Proteins , Leptin , Pharmacology , Microtubule-Associated Proteins , Genetics , Metabolism , RNA, Messenger , Metabolism , RNA, Small Interfering , STAT3 Transcription Factor , Genetics , Metabolism , Signal Transduction , Transfection , Up-RegulationABSTRACT
<p><b>OBJECTIVE</b>To explore the potential mechanisms of leukemia cell resistance to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) -induced apoptosis.</p><p><b>METHODS</b>Cells apoptosis, changes of mitochondrial membrane potential, activity of NF-kappaB, activity of caspase-8 and expressions of apoptosis-related proteins in TRAIL treated K562 and CEM cells, were detected by flowcytometry, ELISA and Western blotting methods, respectively.</p><p><b>RESULTS</b>After treated with TRAIL, the apoptosis indexes were 29.98% and 14.1%, and mitochondrial membrane potential were decreased to 73.25% and 25.4% in K562 and CEM cells respectively. Constitutive level of caspase-8 expression in CEM was lower than that in K562 cells. Both cells became over-expressed Bcl-xL and down-regulated Bax. The ratio of Bcl-xL/Bax in CEM cells was higher than that in K562 cells. Compared with that in K562, the NF-kappaB activity increased significantly in CEM after treatment with TRAIL in early stage.</p><p><b>CONCLUSION</b>CEM cells were more resistant to TRAIL-induced apoptosis than K562 cells did. The potential mechanisms associated with CEM drug resistance might be the lower expression of the constitutive level of caspase-8, lower sensitivity of mitochondrial inner membrane, early increase in NF-KB activity and altered expression of Bcl-2 proteins family.</p>
Subject(s)
Humans , Apoptosis , Apoptosis Regulatory Proteins , Metabolism , Caspase 8 , Metabolism , Drug Resistance, Neoplasm , K562 Cells , Ligands , NF-kappa B , Metabolism , Proto-Oncogene Proteins c-bcl-2 , Metabolism , TNF-Related Apoptosis-Inducing Ligand , Pharmacology , Tumor Cells, CulturedABSTRACT
<p><b>OBJECTIVE</b>To explore the effects of mitochondrial pathways on apoptosis in colon carcinoma cells induced by Tumor necrosis factor related apoptosis inducing ligand and offer evidences for TRAIL application in clinic.</p><p><b>METHODS</b>Apoptosis, integration of mitochondria (including DeltaPsim, cardiolipin), activity of Caspase-9 and release of cytochrome c in colon carcinoma cells SW1116 treated with TRAIL, were detected by means of flowcytometry, fluorometer method and western-blot at the different time point.</p><p><b>RESULTS</b>After treated with TRAIL for 4 hours, the apoptosis index was 32.98%, and the damage of mitochondria occurred with DeltaPsim, cardiolipin decreased, and the activity of Caspase-9 and cytochrome c increased. The Caspase-9 activity at 24 hour was (48.12+/-2.21)micromol.L(-1).h(-1).mg(-1) protein. Mitochondrial damage induced by TRAIL could be inhibited by Caspase inhibitor Z-VAD. fmk.</p><p><b>CONCLUSION</b>Mitochondrial pathways involved in the apoptosis of colon carcinoma cell induced by TRAIL. Cytochrome c was released and Caspase-9 was activated in the Caspase-dependent manner after the damage of mitochondrial.</p>
Subject(s)
Humans , Apoptosis , Cardiolipins , Metabolism , Caspase 9 , Metabolism , Cell Line, Tumor , Cytochromes c , Metabolism , Mitochondria , Metabolism , Mitochondrial Membranes , Metabolism , Receptors, TNF-Related Apoptosis-Inducing Ligand , Metabolism , TNF-Related Apoptosis-Inducing Ligand , MetabolismABSTRACT
<p><b>OBJECTIVE</b>To determine the effects of PCMV-FGEV transfection on the profile of SMMC-7721 hepatocellular in vitro in vivo.</p><p><b>METHODS</b>SMMC-7721 hepatocellular was transfected with PCMV-FGEV antisense, PCMV-VEGF sense and empty vector plasmid encapsulated by lipofectamine. The positive cell clones were selected with G418. The stable transfection and expression of VEGF in the SMMC-7721 hepatocellular were determined by in situ hybridization and immunochemical analysis. The effect of PCMV-FGEV transfection on SMMC-7721 hepatocellular proliferation was observed by MTT colorimetric assay. Flow cytometry was used to determine the effects of PCMV-FGEV transfection on cell apoptosis of SMMC-7721. The growth of transfected cells was also observed in nude mice.</p><p><b>RESULTS</b>There was reduced VEGF expression in SMMC-7721 transfected with PCMV-FGEV confirmed by in situ hybridization and immunohistochemical analysis. There was no effect of PCMV-FGEV transfection on cell proliferation and cell apoptosis of SMMC-7721 in vitro. The growth of cell with PCMV-FGEV transfected was slow in nude mice (vivo) and accompanied with obvious apoptosis. The latent time of tumor in the antisense mice group was 25.0+/-1.8 days, which was longer than that in sense and control group significantly (F=19.455, P<0.01). On the other hand, the average tumor weight in antisense group (0.96 g+/-0.28 g) was the smallest among the three groups (F=21.501, P<0.01).</p><p><b>CONCLUSIONS</b>The expression of VEGF was inhibited by PCMV-FGEV. There was no effect on cell proliferation and cell apoptosis of SMMC-7721 by transferring PCMV-FGEV gene into SMMC-7721 cells in vitro. But in vivo it can inhibit tumor growth and induce cell apoptosis.</p>