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RESEARCH FRONT

Phenotype switching through epigenetic conversion

T. A. L. Brevini A B , G. Pennarossa A , S. Maffei A and F. Gandolfi A
+ Author Affiliations
- Author Affiliations

A Department of Health, Animal Science and Food Safety, UniStem, Laboratory of Biomedical Embryology, Università degli Studi di Milano, Via Celoria 10, 20133 Milan, Italy.

B Corresponding author. Email: tiziana.brevini@unimi.it

Reproduction, Fertility and Development 27(5) 776-783 https://doi.org/10.1071/RD14246
Submitted: 10 July 2014  Accepted: 21 January 2015   Published: 5 March 2015

Abstract

Different cell types have been suggested as candidates for use in regenerative medicine. Embryonic pluripotent stem cells can give rise to all cells of the body and possess unlimited self-renewal potential. However, they are unstable, difficult to control and have a risk of neoplastic transformation. Adult stem cells are safe but have limited proliferation and differentiation abilities and are usually not within easy access. In recent years, induced pluripotent stem (iPS) cells have become a new promising tool in regenerative medicine. However, the use of transgene vectors, commonly required for the induction of iPS cells, seriously limits their use in therapy. The same problem arising from the use of retroviruses is associated with the use of cells obtained through transdifferentiation. Developing knowledge of the mechanisms controlling epigenetic regulation of cell fate has boosted the use of epigenetic modifiers that drive cells into a ‘highly permissive’ state. We recently set up a new strategy for the conversion of an adult mature cell into another cell type. We increased cell plasticity using 5-aza-cytidine and took advantage of a brief window of epigenetic instability to redirect cells to a different lineage. This approach is termed ‘epigenetic conversion’. It is a simple, direct and safe way to obtain both cells for therapy avoiding gene transfection and a stable pluripotent state.

Additional keywords: cell plasticity, regenerative medicine.


References

Addison, M. K., Coley, L. W., Gentry, G. T., Godke, R. A., and Bondioli, K. R. (2011). Epigenetic modification with zebularine and valproic acid and expression of pluripotency genes in bovine adipose stem cells. Reprod. Fertil. Dev. 24, 216–217.
Epigenetic modification with zebularine and valproic acid and expression of pluripotency genes in bovine adipose stem cells.Crossref | GoogleScholarGoogle Scholar |

Bhatla, T., Wang, J., Morrison, D. J., Raetz, E. A., Burke, M. J., Brown, P., and Carroll, W. L. (2012). Epigenetic reprogramming reverses the relapse-specific gene expression signature and restores chemosensitivity in childhood B-lymphoblastic leukemia. Blood 119, 5201–5210.
Epigenetic reprogramming reverses the relapse-specific gene expression signature and restores chemosensitivity in childhood B-lymphoblastic leukemia.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XhtVWjs7zN&md5=0f8f2c51ebdd4d65ac85ecdc58938f0dCAS | 22496163PubMed |

Bird, A. P. (1986). CpG-rich islands and the function of DNA methylation. Nature 321, 209–213.
CpG-rich islands and the function of DNA methylation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL28XktlKns78%3D&md5=88ad10b0e5e4921994c400da4671b426CAS | 2423876PubMed |

Brevini, T. A., Pennarossa, G., Rahman, M. M., Paffoni, A., Antonini, S., Ragni, G., Deeguileor, M., Tettamanti, G., and Gandolfi, F. (2014). Morphological and molecular changes of human granulosa cells exposed to 5-azacytidine and addressed toward muscular differentiation. Stem Cell Rev. 10, 633–642.
Morphological and molecular changes of human granulosa cells exposed to 5-azacytidine and addressed toward muscular differentiation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2cXoslyjs7Y%3D&md5=fbef7b4e1286dba93b6a10c778e984f0CAS | 24858410PubMed |

Chiu, C. P., and Blau, H. M. (1984). Reprogramming cell differentiation in the absence of DNA synthesis. Cell 37, 879–887.
Reprogramming cell differentiation in the absence of DNA synthesis.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2cXlt1Oruro%3D&md5=ae3ec762f2b005fb4605ba6716799ab3CAS | 6744415PubMed |

Chiu, C. P., and Blau, H. M. (1985). 5-Azacytidine permits gene activation in a previously noninducible cell type. Cell 40, 417–424.
5-Azacytidine permits gene activation in a previously noninducible cell type.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2MXht12nt7Y%3D&md5=ba0601f498a2493e0cf21f488c79a6e8CAS | 2578323PubMed |

Choy, M. K., Movassagh, M., Goh, H. G., Bennett, M. R., Down, T. A., and Foo, R. S. (2010). Genome-wide conserved consensus transcription factor binding motifs are hyper-methylated. BMC Genomics 11, 519.
Genome-wide conserved consensus transcription factor binding motifs are hyper-methylated.Crossref | GoogleScholarGoogle Scholar | 20875111PubMed |

Cohen, D. E., and Melton, D. (2011). Turning straw into gold: directing cell fate for regenerative medicine. Nat. Rev. Genet. 12, 243–252.
Turning straw into gold: directing cell fate for regenerative medicine.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXjsVGktL8%3D&md5=3ec0d9bee685a6a47207629c5cae2db2CAS | 21386864PubMed |

De Carvalho, D. D., You, J. S., and Jones, P. A. (2010). DNA methylation and cellular reprogramming. Trends Cell Biol. 20, 609–617.
DNA methylation and cellular reprogramming.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXht1WlsLzP&md5=67fe5ddf52d8598a99b33d623e119b47CAS | 20810283PubMed |

De Coppi, P., Bartsch, G., Siddiqui, M. M., Xu, T., Santos, C. C., Perin, L., Mostoslavsky, G., Serre, A. C., Snyder, E. Y., Yoo, J. J., Furth, M. E., Soker, S., and Atala, A. (2007). Isolation of amniotic stem cell lines with potential for therapy. Nat. Biotechnol. 25, 100–106.
Isolation of amniotic stem cell lines with potential for therapy.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXis1Grtw%3D%3D&md5=47d1681e0d29de53c419630861cd82d4CAS | 17206138PubMed |

Ding, X., Wang, Y., Zhang, D., Wang, Y., Guo, Z., and Zhang, Y. (2008). Increased pre-implantation development of cloned bovine embryos treated with 5-aza-2'-deoxycytidine and trichostatin A. Theriogenology 70, 622–630.
Increased pre-implantation development of cloned bovine embryos treated with 5-aza-2'-deoxycytidine and trichostatin A.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXpsVCrur4%3D&md5=27087a06e8f36a42c57ec4421fe7a725CAS | 18556056PubMed |

Enright, B. P., Kubota, C., Yang, X., and Tian, X. C. (2003). Epigenetic characteristics and development of embryos cloned from donor cells treated by trichostatin A or 5-aza-2'-deoxycytidine. Biol. Reprod. 69, 896–901.
Epigenetic characteristics and development of embryos cloned from donor cells treated by trichostatin A or 5-aza-2'-deoxycytidine.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXmvVeitb8%3D&md5=5aa586f7a109d8b10d8224466176653dCAS | 12748129PubMed |

Galvez, B. G., Sampaolesi, M., Barbuti, A., Crespi, A., Covarello, D., Brunelli, S., Dellavalle, A., Crippa, S., Balconi, G., Cuccovillo, I., Molla, F., Staszewsky, L., Latini, R., Difrancesco, D., and Cossu, G. (2008). Cardiac mesoangioblasts are committed, self-renewable progenitors, associated with small vessels of juvenile mouse ventricle. Cell Death Differ. 15, 1417–1428.
Cardiac mesoangioblasts are committed, self-renewable progenitors, associated with small vessels of juvenile mouse ventricle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXpvFKnsLg%3D&md5=1e4df91948e27cc8a970c53790067769CAS | 18497758PubMed |

Glover, T. W., Coyle-Morris, J., Pearce-Birge, L., Berger, C., and Gemmill, R. M. (1986). DNA demethylation induced by 5-azacytidine does not affect fragile X expression. Am. J. Hum. Genet. 38, 309–318.
| 1:CAS:528:DyaL28XitVWmtLo%3D&md5=61cbac49e0afa555c6805e8727f84bdbCAS | 2420174PubMed |

Goldberg, A. D., Allis, C. D., and Bernstein, E. (2007). Epigenetics: a landscape takes shape. Cell 128, 635–638.
Epigenetics: a landscape takes shape.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXis12ju74%3D&md5=c78fa882356482387fff28e7df20c636CAS | 17320500PubMed |

Harris, D. M., Hazan-Haley, I., Coombes, K., Bueso-Ramos, C., Liu, J., Liu, Z., Li, P., Ravoori, M., Abruzzo, L., Han, L., Singh, S., Sun, M., Kundra, V., Kurzrock, R., and Estrov, Z. (2011). Transformation of human mesenchymal cells and skin fibroblasts into hematopoietic cells. PLoS ONE 6, e21250.
Transformation of human mesenchymal cells and skin fibroblasts into hematopoietic cells.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXotF2gu7o%3D&md5=3ed217b7071ea8573a9ce02015639f5fCAS | 21731684PubMed |

Hemberger, M., Dean, W., and Reik, W. (2009). Epigenetic dynamics of stem cells and cell lineage commitment: digging Waddington's canal. Nat. Rev. Mol. Cell Biol. 10, 526–537.
Epigenetic dynamics of stem cells and cell lineage commitment: digging Waddington's canal.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXosFWhtrY%3D&md5=7bfcf8e7106e6443222982f4e06a95a3CAS | 19603040PubMed |

Huangfu, D., Maehr, R., Guo, W., Eijkelenboom, A., Snitow, M., Chen, A. E., and Melton, D. A. (2008). Induction of pluripotent stem cells by defined factors is greatly improved by small-molecule compounds. Nat. Biotechnol. 26, 795–797.
Induction of pluripotent stem cells by defined factors is greatly improved by small-molecule compounds.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXot1entL0%3D&md5=a757ed7fb09d7c5d77ac503051796b6dCAS | 18568017PubMed |

Ibarretxe, G., Alvarez, A., Canavate, M. L., Hilario, E., Aurrekoetxea, M., and Unda, F. (2012). Cell reprogramming, IPS limitations, and overcoming strategies in dental bioengineering. Stem Cells Int. 2012, 365932.
Cell reprogramming, IPS limitations, and overcoming strategies in dental bioengineering.Crossref | GoogleScholarGoogle Scholar | 22690226PubMed |

Ieda, M., Fu, J.-D., Delgado-Olguin, P., Vedantham, V., Hayashi, Y., Bruneau, B. G., and Srivastava, D. (2010). Direct reprogramming of fibroblasts into functional cardiomyocytes by defined factors. Cell 142, 375–386.
Direct reprogramming of fibroblasts into functional cardiomyocytes by defined factors.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXpvFKrsbY%3D&md5=4d9147bab2517d588decf40ca96b5ec9CAS | 20691899PubMed |

Jones, P. A. (1985a). Altering gene expression with 5-azacytidine. Cell 40, 485–486.
Altering gene expression with 5-azacytidine.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2MXhvFyktr8%3D&md5=585e593454d63a8e81558f1e533a3d39CAS | 2578884PubMed |

Jones, P. A. (1985b). Effects of 5-azacytidine and its 2′-deoxyderivative on cell differentiation and DNA methylation. Pharmacol. Ther. 28, 17–27.
Effects of 5-azacytidine and its 2′-deoxyderivative on cell differentiation and DNA methylation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2MXmtVGisbo%3D&md5=78d095c4a6205c12aeb95b85b9a9236dCAS | 2414786PubMed |

Jopling, C., Boue, S., and Izpisua Belmonte, J. C. (2011). Dedifferentiation, transdifferentiation and reprogramming: three routes to regeneration. Nat. Rev. Mol. Cell Biol. 12, 79–89.
Dedifferentiation, transdifferentiation and reprogramming: three routes to regeneration.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXotlSgsw%3D%3D&md5=17352c40194500cc0813879a2d814178CAS | 21252997PubMed |

Kaji, K., Norrby, K., Paca, A., Mileikovsky, M., Mohseni, P., and Woltjen, K. (2009). Virus-free induction of pluripotency and subsequent excision of reprogramming factors. Nature 458, 771–775.
Virus-free induction of pluripotency and subsequent excision of reprogramming factors.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXisVOrtbk%3D&md5=2fdc2279e472219e650c1ae908254666CAS | 19252477PubMed |

Kishigami, S., Mizutani, E., Ohta, H., Hikichi, T., Thuan, N. V., Wakayama, S., Bui, H. T., and Wakayama, T. (2006). Significant improvement of mouse cloning technique by treatment with trichostatin A after somatic nuclear transfer. Biochem. Biophys. Res. Commun. 340, 183–189.
Significant improvement of mouse cloning technique by treatment with trichostatin A after somatic nuclear transfer.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXhtlCqtbnJ&md5=0ee13079dbb3d0fdc742a9a64478a383CAS | 16356478PubMed |

Lefebvre, B., Belaich, S., Longue, J., Vandewalle, B., Oberholzer, J., Gmyr, V., Pattou, F., and Kerr-Conte, J. (2010). 5′-AZA induces Ngn3 expression and endocrine differentiation in the PANC-1 human ductal cell line. Biochem. Biophys. Res. Commun. 391, 305–309.
5′-AZA induces Ngn3 expression and endocrine differentiation in the PANC-1 human ductal cell line.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXptl2k&md5=37a86cce55f51c42f4546512d0bded2aCAS | 19913512PubMed |

Lengner, C. J. (2010). iPS cell technology in regenerative medicine. Ann. N. Y. Acad. Sci. 1192, 38–44.
iPS cell technology in regenerative medicine.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXmsVSrs70%3D&md5=c4dee115dcdd5f0ed9b26f5c0bf93630CAS | 20392216PubMed |

Li, M., Liu, G. H., and Izpisua Belmonte, J. C. (2012). Navigating the epigenetic landscape of pluripotent stem cells. Nat. Rev. Mol. Cell Biol. 13, 524–535.
Navigating the epigenetic landscape of pluripotent stem cells.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XhtVKnt7vN&md5=b095bb02afac0e99c5b2d1a3ddd9ea10CAS | 22820889PubMed |

Lim, M. L., Vassiliev, I., Richings, N. M., Firsova, A. B., Zhang, C., and Verma, P. J. (2011). A novel, efficient method to derive bovine and mouse embryonic stem cells with in vivo differentiation potential by treatment with 5-azacytidine. Theriogenology 76, 133–142.
A novel, efficient method to derive bovine and mouse embryonic stem cells with in vivo differentiation potential by treatment with 5-azacytidine.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXntFKitbs%3D&md5=81ca89934e14ebd2f128b18e8d9469d6CAS | 21396694PubMed |

Medawar, P. B. and Medawar, J. S. (1983). ‘Aristotle to Zoos: A Philosophical Dictionary of Biology.’ (Harvard University Press: Cambridge.)

Meissner, A., Wernig, M., and Jaenisch, R. (2007). Direct reprogramming of genetically unmodified fibroblasts into pluripotent stem cells. Nat. Biotechnol. 25, 1177–1181.
Direct reprogramming of genetically unmodified fibroblasts into pluripotent stem cells.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtFagt7rL&md5=32ec61672498f4e1120f8080c4f7c4e2CAS | 17724450PubMed |

Milhem, M., Mahmud, N., Lavelle, D., Araki, H., DeSimone, J., Saunthararajah, Y., and Hoffman, R. (2004). Modification of hematopoietic stem cell fate by 5aza 2 deoxycytidine and trichostatinA. Blood 103, 4102–4110.
Modification of hematopoietic stem cell fate by 5aza 2 deoxycytidine and trichostatinA.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXkvVyitr0%3D&md5=2d59c788bb65f4d0c4d2b0f1bfaaac28CAS | 14976039PubMed |

Moschidou, D., Mukherjee, S., Blundell, M. P., Drews, K., Jones, G. N., Abdulrazzak, H., Nowakowska, B., Phoolchund, A., Lay, K., Ramasamy, T. S., Cananzi, M., Nettersheim, D., Sullivan, M., Frost, J., Moore, G., Vermeesch, J. R., Fisk, N. M., Thrasher, A. J., Atala, A., Adjaye, J., Schorle, H., De Coppi, P., and Guillot, P. V. (2012). Valproic acid confers functional pluripotency to human amniotic fluid stem cells in a transgene-free approach. Mol. Ther. 20, 1953–1967.
Valproic acid confers functional pluripotency to human amniotic fluid stem cells in a transgene-free approach.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XpsFOqtbY%3D&md5=ff76e735193d0986c2359b52a11aa8adCAS | 22760542PubMed |

Naeem, N., Haneef, K., Kabir, N., Iqbal, H., Jamall, S., and Salim, A. (2013). DNA methylation inhibitors, 5-azacytidine and zebularine potentiate the transdifferentiation of rat bone marrow mesenchymal stem cells into cardiomyocytes. Cardiovasc. Ther. 31, 201–209.
DNA methylation inhibitors, 5-azacytidine and zebularine potentiate the transdifferentiation of rat bone marrow mesenchymal stem cells into cardiomyocytes.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhsVersL7M&md5=9538d320be025a9572562326d563fd52CAS | 22954287PubMed |

Okano, M., Bell, D. W., Haber, D. A., and Li, E. (1999). DNA methyltransferases Dnmt3a and Dnmt3b are essential for de novo methylation and mammalian development. Cell 99, 247–257.
DNA methyltransferases Dnmt3a and Dnmt3b are essential for de novo methylation and mammalian development.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXnt1Gqsrc%3D&md5=44602078c3a4166ddda06bc1c70feb98CAS | 10555141PubMed |

Okita, K., Ichisaka, T., and Yamanaka, S. (2007). Generation of germline-competent induced pluripotent stem cells. Nature 448, 313–317.
Generation of germline-competent induced pluripotent stem cells.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXnvVeqsL0%3D&md5=7a99bb9c3984f4c8a3cbe73af7e22fb7CAS | 17554338PubMed |

Okita, K., Nakagawa, M., Hyenjong, H., Ichisaka, T., and Yamanaka, S. (2008). Generation of mouse induced pluripotent stem cells without viral vectors. Science 322, 949–953.
Generation of mouse induced pluripotent stem cells without viral vectors.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXhtlaltLzO&md5=481cfcacae6bbf30e6918dcc2063a4adCAS | 18845712PubMed |

Okita, K., Matsumura, Y., Sato, Y., Okada, A., Morizane, A., Okamoto, S., Hong, H., Nakagawa, M., Tanabe, K., Tezuka, K.-I., Shibata, T., Kunisada, T., Takahashi, M., Takahashi, J., Saji, H., and Yamanaka, S. (2011). A more efficient method to generate integration-free human iPS cells. Nat. Methods 8, 409–412.
A more efficient method to generate integration-free human iPS cells.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXktFahtrc%3D&md5=19b3908edd17e9779eda1f0c56042e44CAS | 21460823PubMed |

Pennarossa, G., Maffei, S., Campagnol, M., Tarantini, L., Gandolfi, F., and Brevini, T. A. (2013). Brief demethylation step allows the conversion of adult human skin fibroblasts into insulin-secreting cells. Proc. Natl Acad. Sci. USA 110, 8948–8953.
Brief demethylation step allows the conversion of adult human skin fibroblasts into insulin-secreting cells.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhtFait7zO&md5=225e033249ea5838f0ecd16250ea4040CAS | 23696663PubMed |

Pennarossa, G., Maffei, S., Campagnol, M., Rahman, M. M., Brevini, T. A., and Gandolfi, F. (2014). Reprogramming of pig dermal fibroblast into insulin secreting cells by a brief exposure to 5-aza-cytidine. Stem Cell Rev. 10, 31–43.
Reprogramming of pig dermal fibroblast into insulin secreting cells by a brief exposure to 5-aza-cytidine.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2cXhvFCqtb4%3D&md5=65fcf877a4eedc960aead836876755c8CAS | 24072393PubMed |

Pereyra-Bonnet, F., Gimeno, M. L., Argumedo, N. R., Ielpi, M., Cardozo, J. A., Gimenez, C. A., Hyon, S. H., Balzaretti, M., Loresi, M., Fainstein-Day, P., Litwak, L. E., and Argibay, P. F. (2014). Skin fibroblasts from patients with type 1 diabetes (T1D) can be chemically transdifferentiated into insulin-expressing clusters: a transgene-free approach. PLoS ONE 9, e100369.
Skin fibroblasts from patients with type 1 diabetes (T1D) can be chemically transdifferentiated into insulin-expressing clusters: a transgene-free approach.Crossref | GoogleScholarGoogle Scholar | 24963634PubMed |

Plath, K., and Lowry, W. E. (2011). Progress in understanding reprogramming to the induced pluripotent state. Nat. Rev. Genet. 12, 253–265.
Progress in understanding reprogramming to the induced pluripotent state.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXjsVGkt7k%3D&md5=0b0f110b36e0a92d69a664bfad9190ecCAS | 21415849PubMed |

Rim, J. S., Strickler, K. L., Barnes, C. W., Harkins, L. L., Staszkiewicz, J., Gimble, J. M., Leno, G. H., and Eilertsen, K. J. (2012). Temporal epigenetic modifications differentially regulate ES cell-like colony formation and maturation. SCD 2, 45–57.
Temporal epigenetic modifications differentially regulate ES cell-like colony formation and maturation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhtV2mtLg%3D&md5=ee1fa2196e77677150c9933ea3850221CAS |

Segura-Pacheco, B., Perez-Cardenas, E., Taja-Chayeb, L., Chavez-Blanco, A., Revilla-Vazquez, A., Benitez-Bribiesca, L., and Duenas-Gonzàlez, A. (2006). Global DNA hypermethylation-associated cancer chemotherapy resistance and its reversion with the demethylating agent hydralazine. J. Transl. Med. 4, 32.
Global DNA hypermethylation-associated cancer chemotherapy resistance and its reversion with the demethylating agent hydralazine.Crossref | GoogleScholarGoogle Scholar | 16893460PubMed |

Shen, C. N., Slack, J. M., and Tosh, D. (2000). Molecular basis of transdifferentiation of pancreas to liver. Nat. Cell Biol. 2, 879–887.
Molecular basis of transdifferentiation of pancreas to liver.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXptFSntLw%3D&md5=7c11a10b956cf9682f46c2d81d445fc7CAS | 11146651PubMed |

Shi, L. H., Miao, Y. L., Ouyang, Y. C., Huang, J. C., Lei, Z. L., Yang, J. W., Han, Z. M., Song, X. F., Sun, Q. Y., and Chen, D. Y. (2008). Trichostatin A (TSA) improves the development of rabbit-rabbit intraspecies cloned embryos, but not rabbit-human interspecies cloned embryos. Dev. Dyn. 237, 640–648.
Trichostatin A (TSA) improves the development of rabbit-rabbit intraspecies cloned embryos, but not rabbit-human interspecies cloned embryos.Crossref | GoogleScholarGoogle Scholar | 18265023PubMed |

Spivakov, M., and Fisher, A. G. (2007). Epigenetic signatures of stem-cell identity. Nat. Rev. Genet. 8, 263–271.
Epigenetic signatures of stem-cell identity.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXivVGktbc%3D&md5=cfb8edf67dd3767ede4ce8c15924b18eCAS | 17363975PubMed |

Stadtfeld, M., Nagaya, M., Utikal, J., Weir, G., and Hochedlinger, K. (2008). Induced pluripotent stem cells generated without viral integration. Science 322, 945–949.
Induced pluripotent stem cells generated without viral integration.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXhtlaltLzN&md5=071713cc762533442c31262c6851b2d4CAS | 18818365PubMed |

Sterneckert, J., Hoing, S., and Scholer, H. R. (2012). Concise review: Oct4 and more: the reprogramming expressway. Stem Cells 30, 15–21.
Concise review: Oct4 and more: the reprogramming expressway.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XivVymsLg%3D&md5=1bffb1ed04d3fba3df58783f53a07a2aCAS | 22009686PubMed |

Stresemann, C., and Lyko, F. (2008). Modes of action of the DNA methyltransferase inhibitors azacytidine and decitabine. Int. J. Cancer 123, 8–13.
Modes of action of the DNA methyltransferase inhibitors azacytidine and decitabine.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXmtlantrg%3D&md5=c97e0a48f787513446387fcc2d29fe87CAS | 18425818PubMed |

Surani, M. A., Durcova-Hills, G., Hajkova, P., Hayashi, K., and Tee, W. W. (2008). Germ line, stem cells, and epigenetic reprogramming. Cold Spring Harb. Symp. Quant. Biol. 73, 9–15.
Germ line, stem cells, and epigenetic reprogramming.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXos1ersbY%3D&md5=11301642fa3cb078d3a9e6b0bddbf4b6CAS | 19022742PubMed |

Swain, P. S., Elowitz, M. B., and Siggia, E. D. (2002). Intrinsic and extrinsic contributions to stochasticity in gene expression. Proc. Natl. Acad. Sci. USA 99, 12795–12800.
Intrinsic and extrinsic contributions to stochasticity in gene expression.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XnvFGhsLc%3D&md5=7abd66490683a35d761a4b2608d4f1b7CAS | 12237400PubMed |

Takahashi, K., and Yamanaka, S. (2006). Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cell 126, 663–676.
Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28Xpt1aktbs%3D&md5=5440ad1becdcc24eaaab1bdbb2b23e7aCAS | 16904174PubMed |

Takahashi, K., Tanabe, K., Ohnuki, M., Narita, M., Ichisaka, T., Tomoda, K., and Yamanaka, S. (2007). Induction of pluripotent stem cells from adult human fibroblasts by defined factors. Cell 131, 861–872.
Induction of pluripotent stem cells from adult human fibroblasts by defined factors.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhsVCntbbK&md5=e5f1c95221be9d0a8f2be8b773034b94CAS | 18035408PubMed |

Takeshita, K., Suetake, I., Yamashita, E., Suga, M., Narita, H., Nakagawa, A., and Tajima, S. (2011). Structural insight into maintenance methylation by mouse DNA methyltransferase 1 (Dnmt1). Proc. Natl Acad. Sci. USA 108, 9055–9059.
Structural insight into maintenance methylation by mouse DNA methyltransferase 1 (Dnmt1).Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXnsV2gtrw%3D&md5=30f86eedfd51ee18a56f62895bc19e58CAS | 21518897PubMed |

Tamada, H., Van Thuan, N., Reed, P., Nelson, D., Katoku-Kikyo, N., Wudel, J., Wakayama, T., and Kikyo, N. (2006). Chromatin decondensation and nuclear reprogramming by nucleoplasmin. Mol. Cell. Biol. 26, 1259–1271.
Chromatin decondensation and nuclear reprogramming by nucleoplasmin.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XhsFeqsLw%3D&md5=956f451d08198e263bfcc0c3d9f06203CAS | 16449640PubMed |

Taylor, S. M., and Jones, P. A. (1979). Multiple new phenotypes induced in 10T1/2 and 3T3 cells treated with 5-azacytidine. Cell 17, 771–779.
Multiple new phenotypes induced in 10T1/2 and 3T3 cells treated with 5-azacytidine.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaE1MXlsFWqu7s%3D&md5=c8ec38985ab101c5e3abb58c9d106bbaCAS |

Vierbuchen, T., Ostermeier, A., Pang, Z. P., Kokubu, Y., Sudhof, T. C., and Wernig, M. (2010). Direct conversion of fibroblasts to functional neurons by defined factors. Nature 463, 1035–1041.
Direct conversion of fibroblasts to functional neurons by defined factors.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXhtFCgsr0%3D&md5=6218610bf7d83195b7b51d275aa2c5ebCAS | 20107439PubMed |

Waddington, C. H. (1942). The epigenotype. Endeavour 1, 18–20.

Waddington, C. H. (1957). ‘The Strategy of the Genes: A Discussion of Some Aspects of Theoretical Biology.’ (Allen & Unwin: London.)

Weintraub, H., Tapscott, S. J., Davis, R. L., Thayer, M. J., Adam, M. A., Lassar, A. B., and Miller, A. D. (1989). Activation of muscle-specific genes in pigment, nerve, fat, liver, and fibroblast cell lines by forced expression of MyoD. Proc. Natl Acad. Sci. USA 86, 5434–5438.
Activation of muscle-specific genes in pigment, nerve, fat, liver, and fibroblast cell lines by forced expression of MyoD.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1MXkvFWmurY%3D&md5=ae9d91046939eb83587b00d80e5e3174CAS | 2748593PubMed |

Woltjen, K., Michael, I. P., Mohseni, P., Desai, R., Mileikovsky, M., and Hamalainen, R. (2009). piggyBac transposition reprograms fibroblasts to induced pluripotent stem cells. Nature 458, 766–770.
piggyBac transposition reprograms fibroblasts to induced pluripotent stem cells.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXisVOrtr0%3D&md5=fd09fdaf27f7a4614dd0ff029d464925CAS | 19252478PubMed |

Wozniak, R. J., Klimecki, W. T., Lau, S. S., Feinstein, Y., and Futscher, B. W. (2007). 5-Aza-2'-deoxycytidine-mediated reductions in G9A histone methyltransferase and histone H3 K9 di-methylation levels are linked to tumor suppressor gene reactivation. Oncogene 26, 77–90.
5-Aza-2'-deoxycytidine-mediated reductions in G9A histone methyltransferase and histone H3 K9 di-methylation levels are linked to tumor suppressor gene reactivation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhsFOrsw%3D%3D&md5=3bb0a2b14789029fb578022a7b84e182CAS | 16799634PubMed |

Wu, S. C., and Zhang, Y. (2010). Active DNA demethylation: many roads lead to Rome. Nat. Rev. Mol. Cell Biol. 11, 607–620.
Active DNA demethylation: many roads lead to Rome.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXps1egtbY%3D&md5=059255f728297b3c54c5c119047a18c2CAS | 20683471PubMed |

Xie, H., Ye, M., Feng, R., and Graf, T. (2004). Stepwise reprogramming of B cells into macrophages. Cell 117, 663–676.
Stepwise reprogramming of B cells into macrophages.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXkvVyhsrc%3D&md5=aaf8bd0ef46f831179facbdacb97108cCAS | 15163413PubMed |

Xiong, X., Lan, D., Li, J., Zhong, J., Zi, X., Ma, L., and Wang, Y. (2013). Zebularine and scriptaid significantly improve epigenetic reprogramming of yak fibroblasts and cloning efficiency. Cell. Reprogram. 15, 293–300.
Zebularine and scriptaid significantly improve epigenetic reprogramming of yak fibroblasts and cloning efficiency.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhtFOjurbJ&md5=b36a0b1c7c3c40c57ecd50328cd99a60CAS | 23790013PubMed |

Yamanaka, S. (2009). A fresh look at iPS cells. Cell 137, 13–17.
A fresh look at iPS cells.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXls1Sku7k%3D&md5=94bc4801468494edd65b45045ea2d406CAS | 19345179PubMed |

Yoo, C. B., Chuang, J. C., Byun, H. M., Egger, G., Yang, A. S., Dubeau, L., Long, T., Laird, P. W., Marquez, V. E., and Jones, P. A. (2008). Long-term epigenetic therapy with oral zebularine has minimal side effects and prevents intestinal tumors in mice. Cancer Prev. Res. (Phila.) 1, 233–240.
Long-term epigenetic therapy with oral zebularine has minimal side effects and prevents intestinal tumors in mice.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXptFOisbY%3D&md5=c27349e825ddc489195c0ba6f02ba872CAS | 19138966PubMed |

Yuan, H., Myers, S., Wang, J., Zhou, D., Woo, J. A., Kallakury, B., Ju, A., Bazylewicz, M., Carter, Y. M., Albanese, C., Grant, N., Shad, A., Dritschilo, A., Liu, X., and Schlegel, R. (2012). Use of reprogrammed cells to identify therapy for respiratory papillomatosis. N. Engl. J. Med. 367, 1220–1227.
Use of reprogrammed cells to identify therapy for respiratory papillomatosis.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XhsVKhsLvF&md5=601d7294670457a26bbf8910dc47ead7CAS | 23013073PubMed |

Zhou, Q., and Melton, D. A. (2008). Extreme makeover: converting one cell into another. Cell Stem Cell 3, 382–388.
Extreme makeover: converting one cell into another.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXht12it7bO&md5=b42596cc58116a9171760a17f839dc80CAS | 18940730PubMed |

Zhou, Q., Brown, J., Kanarek, A., Rajagopal, J., and Melton, D. A. (2008). In vivo reprogramming of adult pancreatic exocrine cells to beta-cells. Nature 455, 627–632.
In vivo reprogramming of adult pancreatic exocrine cells to beta-cells.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXhtF2hsbvI&md5=834bd30b74508d0fe307a4513ac74aedCAS | 18754011PubMed |

Zhou, H., Li, W., Zhu, S., Joo, J. Y., Do, J. T., Xiong, W., Kim, J. B., Zhang, K., Scholer, H. R., and Ding, S. (2010). Conversion of mouse epiblast stem cells to an earlier pluripotency state by small molecules. J. Biol. Chem. 285, 29 676–29 680.
Conversion of mouse epiblast stem cells to an earlier pluripotency state by small molecules.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXhtFKks7nK&md5=8cb89a0d1784f4e6922567dd3e864a8aCAS |