Abstract
The cyclin-dependent kinase inhibitor p21WAF1/Cip1 is a critical cell cycle regulator which translocates into the nucleus to participate in DNA repair during DNA damage responses. In the present study, we showed that the tumor suppressor, promyelocytic leukemia protein (PML) contributes to the up-regulation of p21 in a p53-independent pathway. Knock-down of PML in p53-null H1299 and HCT 116 (p53−/−) tumor cells by specific siRNA resulted in down-regulation of p21 protein expression, inhibition of γ-irradiation-induced p21 up-regulation, and a decrease in p21 protein half-life. In PML knockdown H1299 cells, the down-regulation of p21 protein expression was reversed by MG132 treatment indicating that the proteasomal degradation of p21 protein was increased. Thus, PML positively regulates p21 expression by inhibiting proteasome-mediated proteolysis. Knockdown of PML decreased the repair of γ-irradiation-induced double strand breaks (DSBs) as indicated by the delayed disappearance of γ-H2AX foci and a decreased association between p21 and proliferating cell nuclear antigen (PCNA). Over-expression of p21 significantly restored the delayed DSB repair function. Taken together, these data provide evidence for a p53-independent functional relationship between PML and p21 in γ-irradiation-induced DNA damage responses, and identify PML as a positive post-translational regulator of p21 in p53-deficient tumor cells.
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de The H, Lavau C, Marchio A, et al. The PML-RAR alpha fusion mRNA generated by the t(15;17) translocation in acute promyelocytic leukemia encodes a functionally altered RAR. Cell, 1991, 66: 675–684
Virador V M, Flores-Obando R E, Berry A, et al. The human promyelocytic leukemia protein is a tumor suppressor for murine skin carcinogenesis. Mol Carcinog, 2009, 48: 599–609
Gurrieri C, Capodieci P, Bernardi R, et al. Loss of the tumor suppressor PML in human cancers of multiple histologic origins. J Natl Cancer Inst, 2004, 96: 269–279
Liu J F, Song Y, Tian B L, et al. Functional proteomic analysis of promyelocytic leukemia nuclear bodies in irradiation-induced MCF-7 cells. J Biochem, 2010, 148: 659–667
Ching R W, Dellaire G, Eskiw C H, et al. PML bodies: A meeting place for genomic loci? J Cell Sci, 2005, 118: 847–854
Dellaire G, Bazett-Jones D P. PML nuclear bodies: Dynamic sensors of DNA damage and cellular stress. Bioessays, 2004, 26: 963–977
Reineke E L, Kao H Y. PML: An emerging tumor suppressor and a target with therapeutic potential. Cancer Ther, 2009, 7: 219–226
Gottifredi V, Prives C. P53 and PML: New partners in tumor suppression. Trends Cell Biol, 2001, 11: 184–187
Cazzalini O, Scovassi A I, Savio M, et al. Multiple roles of the cell cycle inhibitor p21CDKN1A in the DNA damage response. Mutat Res, 2010, 704: 12–20
Le X F, Vallian S, Mu Z M, et al. Recombinant PML adenovirus suppresses growth and tumorigenicity of human breast cancer cells by inducing G1 cell cycle arrest and apoptosis. Oncogene, 1998, 16: 1839–1849
Ghosh A K, Kanda T, Steele R, et al. Knockdown of MBP-1 in human foreskin fibroblasts induces p53-p21 dependent senescence. PLoS ONE, 2008, 3: e3384
Pearson M, Carbone R, Sebastiani C, et al. PML regulates p53 acetylation and premature senescence induced by oncogenic Ras. Nature, 2000, 406: 207–210
Song Y, Meng X B, Mei Z Z, et al. Direct phosphorylation of p21(WAF1/CIP1) with ATM in DNA damage response (in Chinese). Chinese J Biochem Mol Biol, 2002, 18: 277–281
Bruno S, Ghiotto F, Fais F, et al. The PML gene is not involved in the regulation of MHC class I expression in human cell lines. Blood, 2003, 101: 3514–3519
Kim Y, Starostina N G, Kipreos E T. The CRL4Ctdt2 ubiquitin ligase targets the degradation of p21Cip1 to control replication licensing. Genes Dev, 2008, 22: 2507–2519
Zhang Z, Wang H, Li M, et al. MDM2 is a negative regulator of p21WAF1/CIP1, independent of p53. J Biol Chem, 2004, 279: 16000–16006
Touitou R, Richardson J, Bose S, et al. A degradation signal located in the C-terminus of p21WAF1/CIP1 is a binding site for the C8 a-subunit of the 20S proteasome. EMBO J, 2001, 20: 2367–2375
Kinner A, Wu W, Staudt C, et al. Gamma-H2AX in recognition and signaling of DNA double-strand breaks in the context of chromatin. Nucleic Acids Res, 2008, 36: 5678–5694
Lee J Y, Kim H K, Kim J Y, et al. Nuclear translocation of p21WAF1/CIP1 protein prior to its cytosolic degradation by UV enhances DNA repair and survival. Biochem Biophys Res Commun, 2009, 390: 1361–1366
Perucca P, Cazzalini O, Mortusewicz O, et al. Spatiotemporal dynamics of p21CDKN1A protein recruitment to DNA-damage sites and interaction with proliferating cell nuclear antigen. J Cell Sci, 2006, 119: 1517–1527
Cazzalini O, Perucca P, Savio M, et al. Interaction of p21(CDKN1A) with PCNA regulates the histone acetyltransferase activity of p300 in nucleotide excision repair. Nucleic Acids Res, 2008, 36: 1713–1722
Jung Y S, Qian Y J, Chen X B. Examination of the expanding pathways for the regulation of p21 expression and activity. Cell Signal, 2010, 22: 1003–1012
Tian B L, Mei Z Z, Song Y, et al. Knocking down PML impairs p53 signaling transduction pathway and suppresses irradiation induced apoptosis in breast carcinoma cell MCF-7. J Cell Biochem, 2006, 97: 561–571
Stagno D M, Mendez B A, Foxon J L, et al. Lack of TRF2 in ALT cells causes PML-dependent p53 activation and loss of telomeric DNA. J Cell Biol, 2007, 179: 855–867
Jensen K, Shiels C, Freemont P S. PML protein isoforms and the RBCC/TRIM motif. Oncogene, 2001, 20: 7223–7233
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Cao, L., Song, Y., Tian, B. et al. PML contributes to p53-independent p21 up-regulation in gamma-irradiation induced DNA damage responses. Chin. Sci. Bull. 56, 3148–3154 (2011). https://doi.org/10.1007/s11434-011-4566-0
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DOI: https://doi.org/10.1007/s11434-011-4566-0