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CELL CYCLE, SURVIVAL AND DEATH JIA Hong-Ti ( 贾弘禔 ) DEPT BIOCHEM MOL BIOL.

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Presentation on theme: "CELL CYCLE, SURVIVAL AND DEATH JIA Hong-Ti ( 贾弘禔 ) DEPT BIOCHEM MOL BIOL."— Presentation transcript:

1 CELL CYCLE, SURVIVAL AND DEATH JIA Hong-Ti ( 贾弘禔 ) DEPT BIOCHEM MOL BIOL

2 INTRODUCTION For What Make Choice of This Topic

3 Meier P et al: Apoptosis in Development (Nature, 407:796-801, 2000) Yuan J & Yankner BA: Apoptosis in The Nervous System (Nature, 407:802-809, 2000) Evan GI & Vousden KH: Proliferation, Cell Cycle and Apoptosis in Cancer (Nature, 411:342-348, 2001) Nicholson DW: From Bench to Clinic with Apoptosis-based therapeutic agents (Nature, 407:810-816, 2000)

4 p53 as a cellular superhero exerts a tumor-suppressive role at multiple stages of carcinogenic progression (Nature, 411:342-348, 2001)

5 Mutation of p53 occurs at the point of transition from pre-malignant to invasive lesions, well after activation of some of oncogenes that are thought to trigger p53 response (Nature, 411:342-348, 2001)

6 Cell Cycle and Its Controls (from Mol Biol of The Cell)

7 ATM(ataxia telangiectaxia mutated), checkpoints and the cell cycle. P: phosphorylation; T: transactivation; B: inhibitory blockade; D: degradation (Nature, 407:778, 2000)

8 Apoptotic and survival pathways (Nature, 407:780, 2000)

9 STUDY STRATEGY Two examples Berns K et al: A Large-scale RNAI Screen in Human Cells dentifies New Components of The p53 Pathways (Nature, 428:431-437, 2004) Katou et al: S-phase checkpoint proteins Tof1 and Mrc1 form a stable Replication-pausing complex (Nature, 424: 1078- 1082, 2003

10 Berns K et al: A Large-scale RNAI Screen in Human Cells dentifies New Components of The p53 Pathways (Nature, 428:431-437, 2004)

11 (Nature, 428:431-437, 2004)

12 (Nature, 424: 1078-1082, 2003)

13 Katou et al: S-phase checkpoint proteins Tof1 and Mrc1 form a stable Replication-pausing complex (Nature, 424: 1078-1082, 2003)

14 FACTORS CAN INFLUENCE THE OUTCOMES OF PATHWAY EVENTS EVENTS IN THE CANCER PATHWAY Early 1900s —— The idea that tumors arise from somatic genetic change originated 1970s —— Tumor formation is related to the action of specific genes a) Gene transfer:Gain-of-function genetic alteration/Oncogen (e. g., src ); proto-oncogene ( Ha-ras ) b) Epidemiology/Study of inherited predisposition and Cell Hybridization: Loss-of-function genetic change

15 Nature, 411: 336, 2001

16 FATES OF THE CELLS AFTER LESION Based on Molecular Damages: Phenotypic (Cell Organization or Structure) Alteration Functional Alteration Survival: Cell-cycle arrest Senescence Cancer Cell death: Apoptosis Mitotic catastrophe Necrosis

17 Radiation (UV, X-ray)Chemicals (chemicotherepeutic Drugs) Cell lesions: DNA, RNAs,proteins… Cell-cycle arrest Cell death: apoptosis, Mitotic catastrophe, Necrosis Senescence Cancer

18 FACS

19 Comparing PKH2 fluorescence profiles of the wild-type, p21-/- and p53-/- HCT116 cell lines six days after exposure to doxorubin. The inhibiton or knockout of p53 or p21 decreased but did not abolish drug- or radiation-induced senescence, indicating Partial Requirement for p53 and p21 in treatment-induced senescence. Drug Resistance Update, 4:303, 2001 (43%) (11%) (29%)

20 Drug Resistance Update, 4: 303, 2001

21 MOLECULES IN THE CONTROLS OF THE CELL CYCLE CYCLINs: Forming Cyclin-kinase complexs and determining the sub- cell location; the specific interactions with substrates or upstream regulatory enzymes, and the temporal activations of CDKs Cyclin A: Promoting mature of oocytes and reaching a peak before Cyclin B-kinase complex formation. In human forming a Cyclin A-Cdc2 Co., implicating in DNA repair and transition to G2/M Cyclin B: In yeast Cdc13 for entry into mitosis; Cig1 and Cig2 functions unclear. In human the kinase in Cyclin B- Cdc2 co. reaches a peak in the interphase

22 Cyclin C: In human reaching a peak of transcript in mid-G1, but the partner and function unclear Cyclin D: Isoforms1, 2, and 3, forming a tetramer with Cdk4, PCNA and p21 Cip1/Sdi1/Waf1/Pic1 that plays kinase role; with dephospho-Cdk2 playing anti-Cyclin role. D1 (pro-oncogene) is required for entry into G1 Cyclin E: Forming a kinase activity co with Cdk2, implicating G1/S transition Cyclin F: Similar to Cyclin A Cyclin G: Similar to Cyclin A in mammal; a target for p53 Cyclin H: In mammal

23 CDKs: A family of Ser/Thr protein kinase, forming a complex consisting of a catalitic subunit (CDK) and a regulatory subunit (Cyclin) and playing key roles in cell-cycle Cdk1/Cdc2: Forming a active co with Cyclin B (Cdc13), being required for transitions of G1/S and G2/M Cdk2: In yeast for G1/S transition control; Being active in late G1 and highest in S & G2 in human Cdk3: Passing G1? Cdk4: Forming co with Cyclin D1 Cdk5,6 and 7:

24 E2F: A transcriptional factor binding to E2F binding site in target genes; inactived by binding with pRb and activated by releasing from E2F-pRb co and inducing cell proliferation CKIs : Cdk inhibitors p21, p27, p57 function in S-G2-M transition p21, p57 in G2-M transition p15, 16, 21, 27, 18, 19, 57 in G1 P27, p57 in G0-G1-S transition

25 Checkpoint controls

26

27

28 The Checkpoint Regulatory Mechanism Has An Important Role in Maintaining The Integrity of The Genome Nature, 408: 433, 2000 Genes Dev, 15: 2809, 2001 Curr Opin Cell Biol, 14:237, 2002 G1/S PHASE CHECKPOINT PATHWAY

29 Chromosome Instability and Immunodefiency Syndrome (ICF Syndrome) Caused by Mutations in A DNA Methyltransferase Gene (DNMT3B Gene) The recessive autosomal disorder known as ICF syndrome (for immunodeficiency, centromere instability and facial anormalies; Mendelian Inheritance in Man No 242860) is characterized by variable reductions in serum immunoglobulin levels which cause most ICF patients to succumb to infectious diseases before adulthood. The cytogenetic abnormalities in lymphocytes are … multiradiate chromosomes (1q, 2 x 16q, 16p, 2 x 1q, 2 x 1p) (chr. 1,16,and 9 unmethylation in iuxtacentromeric regions). GL Xu et al found that the mutations in both alleles of a gene encoding DNA methyltransferase 3B. Nature, 402:187, 1999

30 Nature, 411: 366, 2001

31

32 G1-PHASE CHECKPOINT PATHWAY ATM-CHK2-CDC25A-CDK2 axis forms a rapid response system; ATR-CHK1-CDC25A-CDK2; CDC25A-CDK4; ATM-CHK2/ATR-CHK1-P53- p21 pathway (Oncogene, 22:5834, 2003)

33 Oncogene, 22:5834, 2003 S-PHASE CHECKPOINT PATHWAY ATM-CHK2-CDC25A-CDC45 axis forms a rapid response system BRCA1 as a ATM target Mre11-NBS1-RAD50 complex is required for radioresistant DNA synthesis (RDS) MDC1, a newly discovered BRCT-repeat protein as a mediator to recruit repair proteins (Nature 421:952; 961 2003) SMC (Genes Dev 16:560,2002) E2F

34 S-phase Checkpoint Proteins TOF1 and MRC1 Form A Stable Replication-pausing Complex (Nature, 424:1078,2003) This is particularly important in S-phase of the cell-cycle,when genomic DNA is most susceptible to variuous enviromental hazards. When chemical agents damage DNA, activation of checkpoint signalling pathways results in a temporary In cessation of DNA replication. A replication-pausing complex is believed to be created at the arrested forks to activate further checkpoint cascades, leading to repair of the damage DNA. Thus, checkpoint factors are thought to act not only to arrest replication but also to maintain a stable replication complex at replication forks. Recently, Katou et al demonstrated that the checkpoint regulatory proteins Tof1 and Mrc1 interact directly with the DNA replication machinery in S cerevisiae. When hydroxyurea blocks chromosomal replication, this assembly forms a stable pausing sttructure that serves to anchor subsequent DNA repair events.

35 G2/M-PHASE CHECKPOINT PATHWAY Oncogene, 22:5834, 2003 A key effector of G2 checkpoint is CDC2 (CDK1) : ATM-CHK2- CDC25C-CDC2 axis ATR-CHK1- CDC25C-CDC2 axis ATR-CHK1- CDC25A-CDC2 axis Weel-CDC2 inhibition PLK1 (-) and PLK3 (+) (polo-like kinase family) play a crucial roles in initiation and exit from mitosis P21-PCNA-CDC2-Cyclin B complex excludes CDC25C(-)

36 Radiation Res., 159:426, 2003 Caffeine,as a nonspecific inhibitor of ATM and ATR, abolishes mutil- checkpoint responses (including radiation-induced G2 phase checkpoint) and sensitizes cells to radiation-induced killing.

37 Initiation of a G2/M Checkpoint after Ultraviolet Radiation Requires p38 Kinase (Nature, 411: 102, 2001)

38 ROLE OF p21 IN TRANSIENT AND PERMANENT CELL CYCLE ARREST AND MAINTENANCE OF GENOME STABILITY Cancer Lett., 179: 1-14, 2002

39 P21 INDUCTION APPEARS TRANSIENT RATHER THAN SUSTAINED IN ALL PHYSIOLOGICAL SITUATION, INCLUDING NOT ONLY DAMAGE-INDUCED TEMPORARY GROWTH ARREST (QUIESCENCE) BUT ALSO PERMANENT ARREST ASSOCIATED WITH SENESCENCE Drug Resis Update, 4:303, 2001

40 TREATMENT-INDUCED SENESCENCE AND MITOTIC CATASTROPHE IN TUMOR CELLS IF NOT APOPTOSIS Drug Resistance Update, 4: 303, 2001

41 Cells with multiple micronuclei (MN) and apoptotic cells(A) Drug Resistance Update, 4: 303, 2001

42

43 Oncogene, 22:5834, 2003

44 Nature Reviews/Neurosci., 4:1, 2003 Apoptosis Pathways

45

46 Figure 5A

47 Late anaphaseeLate telophase DNA damage triggers Chk2-dependent centrosome inactivation, which induces defects in spindle assembly and chromosome segregation and mitotic catastrophe(Cell, 113, 87-99, 2003)

48 H3(Ser10) Phosphorylation late-prophase anaphase metaphase telophase

49

50 Thank you!


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