MCAF1又被稱之為AM或是ATF7IP，可透過和甲基化區域結合蛋白質MBD1交互作用形成異染色質而有效的抑制基因轉錄。MCAF1能和MBD1轉錄抑制區段結合並召集SETDB1形成複合體結合甲基化DNA而造成基因沉默，此外，在許多人類癌症中發現到MCAF1有較高的表現。至今，關於MCAF1調控細胞增生的機制還尚未清楚。本篇研究中，我們在HeLa,NIH3T3以及人類纖維母細胞IMR90細胞中建立持續表現MCAF1的細胞株，有趣的是，我們發現在持續表現MCAF1蛋白質到HeLa細胞中，會透過促進p21蛋白質表現而抑制細胞生長，特別的是，持續表現MCAF1蛋白質在NIH3T3以及 IMR90細胞中則會誘導細胞走向老化的路徑。由DNA微陣列分析的結果指出，MCAF1所調控的下游基因的確有許多都是包含在調控細胞增生的部分。值得注意的是，我們發現到在不同的臨床癌症檢體中，MCAF1在癌組織以及正常組織中的表現量有明顯差異。由於MCAF1所扮演的角色是在調控細胞增生以及基因轉錄，由本研究發現以及之前的研究，更加顯示MCAF1參與在不同癌症
的進展過程中扮演重要角色。

MBD1-containing chromatin-associated factor 1 (MCAF1), also known as ATFa-associated modulator (AM) and activating transcription factor 7-interacting protein (ATF7IP), is involved in methylated DNA-binding domain protein 1 (MBD1)-dependent transcriptional repression via heterochromatin assembly. MCAF1 can bind the transcriptional repression domain of MBD1 and further recruit SET domain bifurcated 1 (SETDB1) for gene silencing in methylated DNA regions. Additionally, elevated expressions of MCAF1 have been observed in several human cancers. Currently, the mechanisms underlying the MCAF1- regulated cell proliferation are not fully understood. In this study, we established HeLa, NIH3T3 cell lines and human diploid fibroblasts (IMR-90) that exhibited stable expression of ectopic MCAF1. Interestingly, ectopic expression of MCAF1 causes HeLa cells to growth arrest through the induction of p21. Specifically, stable overexpression of MCAF1 into NIH3T3 and IMR90 cells induces cellular senescence. Microarray analysis indicates several genes potentially involved in MCAF1-mediated control of cell proliferation. Notably, the results of analyzing expression levels of MCAF1 between tumors and matched normal tissues showed significant changes (both up- and down-regulation) in its expression in different types of cancer. Because of the functional role of MCAF1 in regulating cell proliferation and transcription, the current investigation, in accordance with previous studies, suggests additional levels of regulation of MCAF1 functions in cancer progression in cell and tissue context-dependent manners.

1.Funayama, R. and Ishikawa, F. (2007) Cellular senescence and chromatin structure. Chromosoma, 116, 431-440.
2.Goldstein, S. (1990) Replicative senescence: the human fibroblast comes of age. Science, 249, 1129-1133.
3.Hayflick, L. and Moorhead, P.S. (1961) The serial cultivation of human diploid cell strains. Experimental cell research, 25, 585-621.
4.Harley, C.B., Futcher, A.B. and Greider, C.W. (1990) Telomeres shorten during ageing of human fibroblasts. Nature, 345, 458-460.
5.Robles, S.J. and Adami, G.R. (1998) Agents that cause DNA double strand breaks lead to p16INK4a enrichment and the premature senescence of normal fibroblasts. Oncogene, 16, 1113-1123.
6.Mitsui, Y. and Schneider, E.L. (1976) Characterization of Fractionated Human Diploid Fibroblast Cell-Populations. Experimental cell research, 103, 23-30.
7.Sherwood, S.W., Rush, D., Ellsworth, J.L. and Schimke, R.T. (1988) Defining Cellular Senescence in Imr-90 Cells - a Flow Cytometric Analysis. Proceedings of the National Academy of Sciences of the United States of America, 85, 9086-9090.
8.Dimri, G.P., Lee, X.H., Basile, G., Acosta, M., Scott, C., Roskelley, C., Medrano, E.E., Linskens, M., Rubelj, I., Pereirasmith, O. et al. (1995) A Biomarker That Identifies Senescent Human-Cells in Culture and in Aging Skin in-Vivo. Proceedings of the National Academy of Sciences of the United States of America, 92, 9363-9367.
9.Rangarajan, A. and Weinberg, R.A. (2003) Opinion - Comparative biology of mouse versus human cells: modelling human cancer in mice. Nat Rev Cancer, 3, 952-959.
10.Schmitt, C.A. (2007) Cellular senescence and cancer treatment. Biochimica et biophysica acta, 1775, 5-20.
11.Narita, M., Nunez, S., Heard, E., Narita, M., Lin, A.W., Hearn, S.A., Spector, D.L., Hannon, G.J. and Lowe, S.W. (2003) Rb-mediated heterochromatin formation and silencing of E2F target genes during cellular senescence. Cell, 113, 703-716.
12.Schulz, L. and Tyler, J. (2005) Heterochromatin focuses on senescence. Molecular cell, 17, 168-170.
13.Adams, P.D. (2007) Remodeling chromatin for senescence. Aging cell, 6, 425-427.
14.Adams, P.D. (2007) Remodeling of chromatin structure in senescent cells and its potential impact on tumor suppression and aging. Gene, 397, 84-93.
15.Ye, X., Zerlanko, B., Zhang, R., Somaiah, N., Lipinski, M., Salomoni, P. and Adams, P.D. (2007) Definition of pRB- and p53-dependent and -independent steps in HIRA/ASF1a-mediated formation of senescence-associated heterochromatin foci. Molecular and cellular biology, 27, 2452-2465.
16.Zhang, R., Chen, W. and Adams, P.D. (2007) Molecular dissection of formation of senescence-associated heterochromatin foci. Molecular and cellular biology, 27, 2343-2358.
17.Banumathy, G., Somaiah, N., Zhang, R., Tang, Y., Hoffmann, J., Andrake, M., Ceulemans, H., Schultz, D., Marmorstein, R. and Adams, P.D. (2009) Human UBN1 is an ortholog of yeast Hpc2p and has an essential role in the HIRA/ASF1a chromatin-remodeling pathway in senescent cells. Molecular and cellular biology, 29, 758-770.
18.Garcia-Cao, M., O'Sullivan, R., Peters, A.H., Jenuwein, T. and Blasco, M.A. (2004) Epigenetic regulation of telomere length in mammalian cells by the Suv39h1 and Suv39h2 histone methyltransferases. Nature genetics, 36, 94-99.
19.Lachner, M., O'Carroll, D., Rea, S., Mechtler, K. and Jenuwein, T. (2001) Methylation of histone H3 lysine 9 creates a binding site for HP1 proteins. Nature, 410, 116-120.
20.Narita, M., Narita, M., Krizhanovsky, V., Nunez, S., Chicas, A., Hearn, S.A., Myers, M.P. and Lowe, S.W. (2006) A novel role for high-mobility group a proteins in cellular senescence and heterochromatin formation. Cell, 126, 503-514.
21.Zhang, R., Poustovoitov, M.V., Ye, X., Santos, H.A., Chen, W., Daganzo, S.M., Erzberger, J.P., Serebriiskii, I.G., Canutescu, A.A., Dunbrack, R.L. et al. (2005) Formation of MacroH2A-containing senescence-associated heterochromatin foci and senescence driven by ASF1a and HIRA. Developmental cell, 8, 19-30.
22.Chang, K.S., Stass, S.A., Chu, D.T., Deaven, L.L., Trujillo, J.M. and Freireich, E.J. (1992) Characterization of a fusion cDNA (RARA/myl) transcribed from the t(15;17) translocation breakpoint in acute promyelocytic leukemia. Molecular and cellular biology, 12, 800-810.
23.Kakizuka, A., Miller, W.H., Jr., Umesono, K., Warrell, R.P., Jr., Frankel, S.R., Murty, V.V., Dmitrovsky, E. and Evans, R.M. (1991) Chromosomal translocation t(15;17) in human acute promyelocytic leukemia fuses RAR alpha with a novel putative transcription factor, PML. Cell, 66, 663-674.
24.Reymond, A., Meroni, G., Fantozzi, A., Merla, G., Cairo, S., Luzi, L., Riganelli, D., Zanaria, E., Messali, S., Cainarca, S. et al. (2001) The tripartite motif family identifies cell compartments. The EMBO journal, 20, 2140-2151.
25.Jensen, K., Shiels, C. and Freemont, P.S. (2001) PML protein isoforms and the RBCC/TRIM motif. Oncogene, 20, 7223-7233.
26.Bernardi, R. and Pandolfi, P.P. (2007) Structure, dynamics and functions of promyelocytic leukaemia nuclear bodies. Nature reviews. Molecular cell biology, 8, 1006-1016.
27.Chu, Y. and Yang, X. (2011) SUMO E3 ligase activity of TRIM proteins. Oncogene, 30, 1108-1116.
28.Shen, T.H., Lin, H.K., Scaglioni, P.P., Yung, T.M. and Pandolfi, P.P. (2006) The mechanisms of PML-nuclear body formation. Molecular cell, 24, 331-339.
29.Zhong, S., Muller, S., Ronchetti, S., Freemont, P.S., Dejean, A. and Pandolfi, P.P. (2000) Role of SUMO-1-modified PML in nuclear body formation. Blood, 95, 2748-2752.
30.Dellaire, G. and Bazett-Jones, D.P. (2004) PML nuclear bodies: dynamic sensors of DNA damage and cellular stress. BioEssays : news and reviews in molecular, cellular and developmental biology, 26, 963-977.
31.Takahashi, Y., Lallemand-Breitenbach, V., Zhu, J. and de The, H. (2004) PML nuclear bodies and apoptosis. Oncogene, 23, 2819-2824.
32.Vernier, M., Bourdeau, V., Gaumont-Leclerc, M.F., Moiseeva, O., Begin, V., Saad, F., Mes-Masson, A.M. and Ferbeyre, G. (2011) Regulation of E2Fs and senescence by PML nuclear bodies. Genes & development, 25, 41-50.
33.Zhong, S., Salomoni, P. and Pandolfi, P.P. (2000) The transcriptional role of PML and the nuclear body. Nature cell biology, 2, E85-90.
34.Fogal, V., Gostissa, M., Sandy, P., Zacchi, P., Sternsdorf, T., Jensen, K., Pandolfi, P.P., Will, H., Schneider, C. and Del Sal, G. (2000) Regulation of p53 activity in nuclear bodies by a specific PML isoform. The EMBO journal, 19, 6185-6195.
35.Kuo, H.Y., Chen, Y.C., Chang, H.Y., Jeng, J.C., Lin, E.H., Pan, C.M., Chang, Y.W., Wang, M.L., Chou, Y.T., Shih, H.M. et al. (2013) The PML isoform IV is a negative regulator of nuclear EGFR's transcriptional activity in lung cancer. Carcinogenesis.
36.Ferbeyre, G., de Stanchina, E., Querido, E., Baptiste, N., Prives, C. and Lowe, S.W. (2000) PML is induced by oncogenic ras and promotes premature senescence. Genes & development, 14, 2015-2027.
37.Fujita, N., Watanabe, S., Ichimura, T., Ohkuma, Y., Chiba, T., Saya, H. and Nakao, M. (2003) MCAF mediates MBD1-dependent transcriptional repression. Molecular and cellular biology, 23, 2834-2843.
38.Ichimura, T., Watanabe, S., Sakamoto, Y., Aoto, T., Fujita, N. and Nakao, M. (2005) Transcriptional repression and heterochromatin formation by MBD1 and MCAF/AM family proteins. The Journal of biological chemistry, 280, 13928-13935.
39.Uchimura, Y., Ichimura, T., Uwada, J., Tachibana, T., Sugahara, S., Nakao, M. and Saitoh, H. (2006) Involvement of SUMO modification in MBD1- and MCAF1-mediated heterochromatin formation. The Journal of biological chemistry, 281, 23180-23190.
40.Liu, L., Ishihara, K., Ichimura, T., Fujita, N., Hino, S., Tomita, S., Watanabe, S., Saitoh, N., Ito, T. and Nakao, M. (2009) MCAF1/AM is involved in Sp1-mediated maintenance of cancer-associated telomerase activity. The Journal of biological chemistry, 284, 5165-5174.
41.Bischof, O., Kirsh, O., Pearson, M., Itahana, K., Pelicci, P.G. and Dejean, A. (2002) Deconstructing PML-induced premature senescence. The EMBO journal, 21, 3358-3369.
42.Fu, C., Ahmed, K., Ding, H., Ding, X., Lan, J., Yang, Z., Miao, Y., Zhu, Y., Shi, Y., Zhu, J. et al. (2005) Stabilization of PML nuclear localization by conjugation and oligomerization of SUMO-3. Oncogene, 24, 5401-5413.
43.Mukhopadhyay, D., Ayaydin, F., Kolli, N., Tan, S.H., Anan, T., Kametaka, A., Azuma, Y., Wilkinson, K.D. and Dasso, M. (2006) SUSP1 antagonizes formation of highly SUMO2/3-conjugated species. The Journal of cell biology, 174, 939-949.
44.Fan, J., Wray, J., Meng, X. and Shen, Z. (2009) BCCIP is required for the nuclear localization of the p21 protein. Cell cycle, 8, 3019-3024.
45.Wang, Y., Liu, Y., Lu, J., Zhang, P., Wang, Y., Xu, Y., Wang, Z., Mao, J.H. and Wei, G. (2013) Rapamycin inhibits FBXW7 loss-induced epithelial-mesenchymal transition and cancer stem cell-like characteristics in colorectal cancer cells. Biochemical and biophysical research communications, 434, 352-356.
46.Liu, Y., Huang, Y., Wang, Z., Huang, Y., Li, X., Louie, A., Wei, G. and Mao, J.H. (2013) Temporal mTOR inhibition protects Fbxw7-deficient mice from radiation-induced tumor development. Aging, 5, 111-119.
47.Wang, C., Yu, G., Liu, J., Wang, J., Zhang, Y., Zhang, X., Zhou, Z. and Huang, Z. (2012) Downregulation of PCDH9 predicts prognosis for patients with glioma. Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia, 19, 541-545.
48.Mei, J., Li, M.Q., Ding, D., Li, D.J., Jin, L.P., Hu, W.G. and Zhu, X.Y. (2013) Indoleamine 2,3-dioxygenase-1 (IDO1) enhances survival and invasiveness of endometrial stromal cells via the activation of JNK signaling pathway. International journal of clinical and experimental pathology, 6, 431-444.
49.Said, H.M., Hagemann, C., Carta, F., Katzer, A., Polat, B., Staab, A., Scozzafava, A., Anacker, J., Vince, G.H., Flentje, M. et al. (2013) Hypoxia induced CA9 inhibitory targeting by two different sulfonamide derivatives including Acetazolamide in human Glioblastoma. Bioorganic & medicinal chemistry, 21, 3949-3957.
50.Hsu, C.C., Lee, Y.C., Yeh, S.H., Chen, C.H., Wu, C.C., Wang, T.Y., Chen, Y.N., Hung, L.Y., Liu, Y.W., Chen, H.K. et al. (2012) 58-kDa microspherule protein (MSP58) is novel Brahma-related gene 1 (BRG1)-associated protein that modulates p53/p21 senescence pathway. The Journal of biological chemistry, 287, 22533-22548.
51.Nguyen, L.A., Pandolfi, P.P., Aikawa, Y., Tagata, Y., Ohki, M. and Kitabayashi, I. (2005) Physical and functional link of the leukemia-associated factors AML1 and PML. Blood, 105, 292-300.
52.Xu, Z.X., Zou, W.X., Lin, P. and Chang, K.S. (2005) A role for PML3 in centrosome duplication and genome stability. Molecular cell, 17, 721-732.
53.Oh, W., Ghim, J., Lee, E.W., Yang, M.R., Kim, E.T., Ahn, J.H. and Song, J. (2009) PML-IV functions as a negative regulator of telomerase by interacting with TERT. Journal of cell science, 122, 2613-2622.
54.Hassona, Y., Cirillo, N., Lim, K.P., Herman, A., Mellone, M., Thomas, G.J., Pitiyage, G.N., Parkinson, E.K. and Prime, S.S. (2013) Progression of genotype-specific oral cancer leads to senescence of cancer-associated fibroblasts and is mediated by oxidative stress and TGF-beta. Carcinogenesis, 34, 1286-1295.
55.許絲婷. (2011) 探討MCAF1蛋白質調控端粒酶TERT 基因轉錄之活性. 國立
成功大學碩士論文.