Cellular senescence is an irreversible cell cycle arrest triggered by the activation of oncogenes or mitogenic signaling as well as the enforced expression of tumor suppressors such as p53, p16INK4A and promyelocytic ...Cellular senescence is an irreversible cell cycle arrest triggered by the activation of oncogenes or mitogenic signaling as well as the enforced expression of tumor suppressors such as p53, p16INK4A and promyelocytic leukemia protein （PML） in normal cells. E2F-binding protein 1 （E2FBP1）, a transcription regulator for E2F, induces PML reduction and suppresses the formation of PML-nuclear bodies, whereas the down-regulation of E2FBP1 provokes the PML-dependent premature senescence in human normal fibroblasts. Here we report that the depletion of E2FBP1 induces the accumulation of PML through the Ras-dependent activation of MAP kinase signaling. The cellular levels of p16INK4A and p53 are elevated during premature senescence induced by depletion of E2FBP1, and the depletion of p16INK4A, but not p53 rescued senescent cells from growth arrest. Therefore, the premature senescence induced by E2FBP1 depletion is achieved through the pl6INK4A-Rb pathway. Similar to human normal fibroblasts, the growth inhibition induced by E2FBP1 depletion is also observed in human tumor cells with intact p16INK4A and Rb. These results suggest that E2FBP1 functions as a critical antagonist to the pI6INK4A-Rb tumor suppressor machinery by regulating PML stability.展开更多
Objective: To investigate the effects of anti-PML (promyelocytic leukemia) or anti-PML/RAR( (promyelocytic leukemia/retionic acid receptor() antisense oligonucleotides on cell growth, expression of PML-RAR( mRNA and P...Objective: To investigate the effects of anti-PML (promyelocytic leukemia) or anti-PML/RAR( (promyelocytic leukemia/retionic acid receptor() antisense oligonucleotides on cell growth, expression of PML-RAR( mRNA and PML-RAR(/PML protein location of NB4 cell lines. Methods: RT-PCR was used for detecting PML-RAR( mRNA expression, trypan blue exclusion for cell count, methylcellose assay for leukemic colony forming unit detection, immuno- fluorescence for PML-RAR(/PML protein location. Results: Both anti-PML start codon region antisence (STAS) and anti-PML-RAR( fusion region antisence (FUAS) could inhibit cell growth and the formation of acute myelocytic colony forming unit of cells(AML-CFU). Cells become partial differentiated at days 5, being more obvious in FUAS-treated cells than in STAS ones. Down regulation of PML-RAR( mRNA expression occurred at 24 hours in STAS and FUAS-treated cells and maintained for up to 72 hours. Immuno-fluorescence analysis with anti-PML monoclonal antibody showed a remarkable decrease even complete disappearance of microgranules. The residual granules became enlarged as discrete dots (<10 per cell), similar to normal POD structure in some STAS-treated cells at 24 hours. At 72 hours, nearly all the granules disappeared. Similar changes were observed in FUAS-treated cells. Conclusion: Both PML and PML-RAR( antisence oligonucleotides can specially block the expression of PML-RAR( at mRNA and protein levels. PML protein is implicated in the regulations of cell differentiation.展开更多
Acute promyelocytic leukemia (APL) represents the first example o f a human cancer successfully treated with a differentiation reducer, all-trans retinoic acid. APL is also characterized by a specific chromosome trans...Acute promyelocytic leukemia (APL) represents the first example o f a human cancer successfully treated with a differentiation reducer, all-trans retinoic acid. APL is also characterized by a specific chromosome translocution t (15; 17). In this work, using techniques of molecular biology, we demonstrated that the gene coding for the retinoic acid receptor alpha (RARA), normally located on chromosome 17, was disrupted by the t (15; 17) and fused with the PML gene on chromosome 15. The chromosome 17 breaks were mapped consistently within the second intron of the RARA gene while the chromosome 15 breaks were clustered in two limited regions within the PML gene. Molecular cloning and sequence analysis of part of the PML gene allowed to establish a specific "nested" reverse transcription/polymerase chain reaction (PCR) procedure to characterize the expression patterns of the PML-RARA fusion gene. Different iso forms of the fusion transcripts were discovered which were produced as a result of distinct PML gene rearrangements. The biological activity of the PML-RARA fusion gene and its iso forms should be further explored.展开更多
基金supported by a Grant-in Aid for Scientific Research from the Japan Society for the Promotion of Science
文摘Cellular senescence is an irreversible cell cycle arrest triggered by the activation of oncogenes or mitogenic signaling as well as the enforced expression of tumor suppressors such as p53, p16INK4A and promyelocytic leukemia protein （PML） in normal cells. E2F-binding protein 1 （E2FBP1）, a transcription regulator for E2F, induces PML reduction and suppresses the formation of PML-nuclear bodies, whereas the down-regulation of E2FBP1 provokes the PML-dependent premature senescence in human normal fibroblasts. Here we report that the depletion of E2FBP1 induces the accumulation of PML through the Ras-dependent activation of MAP kinase signaling. The cellular levels of p16INK4A and p53 are elevated during premature senescence induced by depletion of E2FBP1, and the depletion of p16INK4A, but not p53 rescued senescent cells from growth arrest. Therefore, the premature senescence induced by E2FBP1 depletion is achieved through the pl6INK4A-Rb pathway. Similar to human normal fibroblasts, the growth inhibition induced by E2FBP1 depletion is also observed in human tumor cells with intact p16INK4A and Rb. These results suggest that E2FBP1 functions as a critical antagonist to the pI6INK4A-Rb tumor suppressor machinery by regulating PML stability.
基金the National Natural Science Foundation of China(No. 39590291).
文摘Objective: To investigate the effects of anti-PML (promyelocytic leukemia) or anti-PML/RAR( (promyelocytic leukemia/retionic acid receptor() antisense oligonucleotides on cell growth, expression of PML-RAR( mRNA and PML-RAR(/PML protein location of NB4 cell lines. Methods: RT-PCR was used for detecting PML-RAR( mRNA expression, trypan blue exclusion for cell count, methylcellose assay for leukemic colony forming unit detection, immuno- fluorescence for PML-RAR(/PML protein location. Results: Both anti-PML start codon region antisence (STAS) and anti-PML-RAR( fusion region antisence (FUAS) could inhibit cell growth and the formation of acute myelocytic colony forming unit of cells(AML-CFU). Cells become partial differentiated at days 5, being more obvious in FUAS-treated cells than in STAS ones. Down regulation of PML-RAR( mRNA expression occurred at 24 hours in STAS and FUAS-treated cells and maintained for up to 72 hours. Immuno-fluorescence analysis with anti-PML monoclonal antibody showed a remarkable decrease even complete disappearance of microgranules. The residual granules became enlarged as discrete dots (<10 per cell), similar to normal POD structure in some STAS-treated cells at 24 hours. At 72 hours, nearly all the granules disappeared. Similar changes were observed in FUAS-treated cells. Conclusion: Both PML and PML-RAR( antisence oligonucleotides can specially block the expression of PML-RAR( at mRNA and protein levels. PML protein is implicated in the regulations of cell differentiation.
文摘Acute promyelocytic leukemia (APL) represents the first example o f a human cancer successfully treated with a differentiation reducer, all-trans retinoic acid. APL is also characterized by a specific chromosome translocution t (15; 17). In this work, using techniques of molecular biology, we demonstrated that the gene coding for the retinoic acid receptor alpha (RARA), normally located on chromosome 17, was disrupted by the t (15; 17) and fused with the PML gene on chromosome 15. The chromosome 17 breaks were mapped consistently within the second intron of the RARA gene while the chromosome 15 breaks were clustered in two limited regions within the PML gene. Molecular cloning and sequence analysis of part of the PML gene allowed to establish a specific "nested" reverse transcription/polymerase chain reaction (PCR) procedure to characterize the expression patterns of the PML-RARA fusion gene. Different iso forms of the fusion transcripts were discovered which were produced as a result of distinct PML gene rearrangements. The biological activity of the PML-RARA fusion gene and its iso forms should be further explored.
基金supported by the Natio-nal High-tech R&D Program(863 Program)(grant No.2006AA02A405)the Beijing Municipal Science&Tech-nology Commission"Health care of Beijing citizens"(2011)
文摘急性早幼粒细胞白血病(APL)接受维甲酸和砷剂诱导治疗早期的分子动力学及其临床意义尚不清楚。本研究对32例初治APL进行动态检测,利用实时定量PCR和间期荧光原位杂交(FISH)方法检测PML-RARα转录本水平(PML-RARα/ABL)和细胞遗传学。结果表明,诱导14 d时PML-RARα转录本水平比治疗前显著升高(40.10%和57.74%,P<0.01),诱导28 d和巩固治疗结束时PML-RARα转录本分别为:6.97%和0%。在诱导治疗14 d和28 d分别有65.62%和31.25%患者发生PML-RARα转录本增加。治疗前、诱导14 d和诱导28 d PML-RARα拷贝数/每个APL细胞为0.9,2.2,1.4(PML-RARα/ABL×2/APL细胞%)。中位随访时间为22个月,32例患者均无复发。结论:PML-RARα表达上调是急性早幼粒细胞白血病接受维甲酸和砷剂联合诱导治疗过程中一个普遍现象,对疾病预后无影响。
