Objective To investigate arsenic trioxide (As 2O 3)-induced apoptosis and the effects on cell nuclear matrix related protein promyelocytic leukaemia (PML). Methods HepG2 cells were cultured in MEM medium and treat...Objective To investigate arsenic trioxide (As 2O 3)-induced apoptosis and the effects on cell nuclear matrix related protein promyelocytic leukaemia (PML). Methods HepG2 cells were cultured in MEM medium and treated with 0.5, 2, 5 and 10 μmol/L As 2O 3 for either 24 h or 96 h at each concentration. In situ terminal deoxynucleotidyl transferase (TdT) labeling (TUNEL) and DNA ladders were used to detect apoptosis. Confocal microscopy and Western blotting were used to observe the expression of PML. Results The growth rates of HepG2 cells were slower in the As 2O 3 treated than the untreated control group. DNA ladder and TUNEL positive apoptotic cells could be detected in As 2O 3 treated groups. The expression of PML decreased in HepG2 cells with 2 μmol/L As 2O 3 treatment. Confocal images demonstrated that the expression of PML protein in HepG2 cell nuclei decreased after treatment with 2 μmol/L As 2O 3, and micropunctates characteristic of PML protein in HepG2 cell nuclei disappeared after treatment with 5 μmol/L As 2O 3.Conclusions Our results show that arsenic trioxide can significantly inhibit the growth of HepG2 cells in vitro. As 2O 3 induces apoptosis in HepG2 tumor cells in a time and concentration dependent manner. As 2O 3 may degrade the PML protein in HepG2 cell nuclei. The decreased expression of PML in As 2O 3 treated tumor cells is most likely to be caused by apoptosis. Nuclear matrix associated protein PML could be the target of As 2O 3 therapy.展开更多
Aberrant expression of annexin A2-SI00A10 heterotetramer （AIIt） associated with PML/RARα fusion protein causes lethal hyperfibrinolysis in acute promyelocytic leukemia （APL）, but the mechanism is unclear. To faci...Aberrant expression of annexin A2-SI00A10 heterotetramer （AIIt） associated with PML/RARα fusion protein causes lethal hyperfibrinolysis in acute promyelocytic leukemia （APL）, but the mechanism is unclear. To facilitate the investigation of regulatory association between ANXA2 and promyelocytic leukemia/retinoic acid receptor α （PML/RARα） fusion protein, this work was performed to determine the transcription start site of ANXA2 promoter with rapid amplification of 5＇-cDNA ends analysis. Zinc-induced U937/PR9 cells expressed PML/RARα fusion protein, and resultant increases in ANXA2 transcripts and translational expressions of both ANXA2 and S100A10, while S100A10 transcripts remained constitutive. The transactivation of ANXA2 promoter by PML/RARα fusion protein was 3.29 ± 0.13 fold higher than that by control pSG5 vector or wild-type RARer. The overexpression of ANXA2 in U937 transfected with full-length ANXA2 cDNA was associated with increased S100A10 subunit, although S100A10 transcripts remained constitutive. The tPA-dependent initial rate of plasmin generation （IRPG） in zinc-treated U937/PR9 increased by 2.13-fold, and cell invasiveness increased by 27.6%. Antibodies against ANXA2, S100A10, or combination of both all remarkably inhibited the IRPG and invasiveness in U937/PR9 and NB4. Treatment of zinc-induced U937/PR9 or circulating APL blasts with all-trans retinoic acid （ATRA） significantly reduced cell surface ANXA2 and S100A10 and associated reductions in IRPG and invasiveness. Thus, PML/RARα fusion protein transactivated the ANXA2 promoter to upregulate ANXA2 and accumulate S100A10. Increased AIIt promoted IRPG and invasiveness, both of which were partly abolished by antibodies against ANXA2 and S100A10 or by ATRA.展开更多
文摘Objective To investigate arsenic trioxide (As 2O 3)-induced apoptosis and the effects on cell nuclear matrix related protein promyelocytic leukaemia (PML). Methods HepG2 cells were cultured in MEM medium and treated with 0.5, 2, 5 and 10 μmol/L As 2O 3 for either 24 h or 96 h at each concentration. In situ terminal deoxynucleotidyl transferase (TdT) labeling (TUNEL) and DNA ladders were used to detect apoptosis. Confocal microscopy and Western blotting were used to observe the expression of PML. Results The growth rates of HepG2 cells were slower in the As 2O 3 treated than the untreated control group. DNA ladder and TUNEL positive apoptotic cells could be detected in As 2O 3 treated groups. The expression of PML decreased in HepG2 cells with 2 μmol/L As 2O 3 treatment. Confocal images demonstrated that the expression of PML protein in HepG2 cell nuclei decreased after treatment with 2 μmol/L As 2O 3, and micropunctates characteristic of PML protein in HepG2 cell nuclei disappeared after treatment with 5 μmol/L As 2O 3.Conclusions Our results show that arsenic trioxide can significantly inhibit the growth of HepG2 cells in vitro. As 2O 3 induces apoptosis in HepG2 tumor cells in a time and concentration dependent manner. As 2O 3 may degrade the PML protein in HepG2 cell nuclei. The decreased expression of PML in As 2O 3 treated tumor cells is most likely to be caused by apoptosis. Nuclear matrix associated protein PML could be the target of As 2O 3 therapy.
文摘Aberrant expression of annexin A2-SI00A10 heterotetramer （AIIt） associated with PML/RARα fusion protein causes lethal hyperfibrinolysis in acute promyelocytic leukemia （APL）, but the mechanism is unclear. To facilitate the investigation of regulatory association between ANXA2 and promyelocytic leukemia/retinoic acid receptor α （PML/RARα） fusion protein, this work was performed to determine the transcription start site of ANXA2 promoter with rapid amplification of 5＇-cDNA ends analysis. Zinc-induced U937/PR9 cells expressed PML/RARα fusion protein, and resultant increases in ANXA2 transcripts and translational expressions of both ANXA2 and S100A10, while S100A10 transcripts remained constitutive. The transactivation of ANXA2 promoter by PML/RARα fusion protein was 3.29 ± 0.13 fold higher than that by control pSG5 vector or wild-type RARer. The overexpression of ANXA2 in U937 transfected with full-length ANXA2 cDNA was associated with increased S100A10 subunit, although S100A10 transcripts remained constitutive. The tPA-dependent initial rate of plasmin generation （IRPG） in zinc-treated U937/PR9 increased by 2.13-fold, and cell invasiveness increased by 27.6%. Antibodies against ANXA2, S100A10, or combination of both all remarkably inhibited the IRPG and invasiveness in U937/PR9 and NB4. Treatment of zinc-induced U937/PR9 or circulating APL blasts with all-trans retinoic acid （ATRA） significantly reduced cell surface ANXA2 and S100A10 and associated reductions in IRPG and invasiveness. Thus, PML/RARα fusion protein transactivated the ANXA2 promoter to upregulate ANXA2 and accumulate S100A10. Increased AIIt promoted IRPG and invasiveness, both of which were partly abolished by antibodies against ANXA2 and S100A10 or by ATRA.
