Somatic cell reprogramming for regenerative medicine: SCNT vs. iPS cells

BioEssays ◽  
2012 ◽  
Vol 34 (6) ◽  
pp. 472-476 ◽  
Author(s):  
Guangjin Pan ◽  
Tao Wang ◽  
Hongjie Yao ◽  
Duanqing Pei
Keyword(s):  
Regenerative Medicine ◽  
Somatic Cell ◽  
Ips Cells ◽  
Cell Reprogramming ◽  
Somatic Cell Reprogramming

Reprogramming of MLL-AF9 Leukemic Cells Into Pluripotent Stem Cells in Mice

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 205-205
Author(s):  
Yanfeng Liu ◽  
Hui Cheng ◽  
Linping Hu ◽  
Jing Xu ◽  
Weiping Yuan ◽  
...  
Keyword(s):  
Somatic Cell ◽  
Cancer Cells ◽  
Cell Lines ◽  
Fusion Gene ◽  
Ips Cells ◽  
Leukemic Cells ◽  
Cell Reprogramming ◽  
Germ Layers ◽  
Ips Cell ◽  
Somatic Cell Reprogramming

Abstract Abstract 205 Somatic cell reprogramming into a pluripotent state by the so called “iPS” technology not only holds great promise in regenerative medicine, but also provides a powerful tool to study pathological dedifferentiation processes such as tumorigenesis. In fact, the four “Yamanaka” reprogramming transcription factors used for iPS induction (Oct4, Sox2, and especially C-Myc and KLF4) are known for their direct or indirect oncogenic activities. In addition, the two most well-known tumor suppressor pathways, p53 and Rb, have been shown to also suppress iPS reprogramming. These suggest that tumorigenesis and somatic cell reprogramming may share some common mechanisms. Although it was previously reported that malignant cell lines or primary cancer cells could be reprogrammed by nuclear transfer or the iPS approach, it has not been definitively demonstrated whether primary transformed cells (not established tumor cell lines) can be reprogrammed into iPS cells with a full-term developmental potential in vivo. To this end, we first established an acute myeloid leukemia (AML) mouse model by over-expressing the human MLL (mixed lineage leukemia)-AF9 fusion gene in hematopoietic cells harvested from transgenic mice that carry the Yamanaka reprogramming factors under the control of doxycycline (Dox) (Brambrink et al., 2008). We chose MLL leukemia (a group of aggressive forms of acute leukemia with poor prognosis) because the genome of MLL leukemic cells was shown to be relatively stable, thereby increasing the likelihood of successful reprogramming of the leukemic nuclei. The purified leukemic cells were then induced into iPS cells by an addition of Dox under mouse embryonic stem cell (ESC) culture conditions. The MLL-AF9 fusion gene was present in all the iPS colonies, but its expression was silent in the established iPS cell lines. The generated iPS cell lines were similar to normal ES cells lines, as shown by both genetic and epigenetic signatures. The MLL-AF9 iPS cell lines could give rise to teratomas consisting of three germ layers after injection into a SCID mouse. More importantly, some MLL-AF9 iPS cell lines were able to produce chimeras at a high rate through blastocyst injection. Noticeably however, most chimeras developed the same type of AML within 2 months, which was correlated with re-activation of the MLL-AF9 gene. Consistently, DNA methylation of a MLL-AF9 promoter differed significantly between original leukemic cells, derived iPS cells and the re-occurred leukemic cells from the chimera mice, for which the de novo DNA methtylase, DNA3b, rather than other methylating enzymes, seemed to be responsible. RNA-seq analysis is under way to further define the target genes involved in the differences of these interchangeable cell types. In summary, this study demonstrates for the first time that primary leukemia cells can be fully reprogrammed into iPS cells with the potential of developing into three germ layers and contributing to chimeric mice. The interchangeable feature between leukemic cells and iPS cells offers a unique opportunity to define the distinct mechanisms between pluripotency and malignancy, thereby having implications for specific manipulations of iPS vs. cancer cells and particularly for selective targeting of the leukemic cells harboring a MLL fusion gene. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Global epigenetic changes during somatic cell reprogramming to iPS cells

2011 ◽  
Vol 3 (6) ◽  
pp. 341-350 ◽  
Author(s):  
Anna Mattout ◽  
Alva Biran ◽  
Eran Meshorer
Keyword(s):  
Somatic Cell ◽  
Ips Cells ◽  
Cell Reprogramming ◽  
Epigenetic Changes ◽  
Somatic Cell Reprogramming

316 INDUCTION OF PIG INDUCED PLURIPOTENT STEM CELLS BY RECOMBINANT PROTEINS ENCODED BY DEFINED FACTORS

2011 ◽  
Vol 23 (1) ◽  
pp. 254
Author(s):  
Y. H. Zhang ◽  
H. G. Cao ◽  
Y. S. Li ◽  
H. Q. Yin ◽  
X. P. Sun ◽  
...  
Keyword(s):  
Stem Cell ◽  
Somatic Cell ◽  
Recombinant Proteins ◽  
Fusion Proteins ◽  
Ips Cells ◽  
Cell Reprogramming ◽  
Potential Hazard ◽  
Somatic Cell Reprogramming ◽  
Prokaryotic Expression Vector ◽  
Induced Pluripotent

Pluripotent cells derived from any differentiated cell type through ectopic expression of transcription factors were designated as induced pluripotent stem (iPS) cells, exhibiting similar morphology and growth properties to embryonic stem (ES) cells besides expressing ES cell marker. Because iPS have the ability to differentiate into all types of cells, iPS cell technology is thought to have enormous potential for generating disease models, drug screening, toxicology, and regenerative medicine. However, for virus-mediated transfection of defined factors, the exogenous genes generally would be randomly inserted into the target cell’s genome, possibly bringing the potential hazard of insertional mutagenesis. Therefore, it is necessary to seek some new methods to induce somatic cell reprogramming without viruses. With instruction from the work of Zhou et al. (2009 Cell Stem Cell 4, 381–384), in the present study we attempted to use defined factors recombinant proteins-carried cell-penetrating peptide for the generation of porcine iPS cells, which would be a benefit for safe applications of iPS cells. Defined factors genes were amplified by PCR with specific primers of 9 arginines (R9) from recombinant plasmid pLL-hOCT4/pSox2/pMyc/pKlf4-EGFP (Yin et al. 2010 Prog. Biochem. Biophys. 37, 607–612) and inserted into prokaryotic expression vector pET-28a-EGFP. After DNA sequencing confirmation, the 4 recombinant plasmids were then transformed into BL21 strains, respectively. After IPTG induction, hOCT4/pSox2/pMyc/pKlf4-R9-EGFP fusion proteins were purified using Novagen His-Bind kit and confirmed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis, respectively. Then, defined factors recombinant proteins were added into pig fetal fibroblasts (PFF) medium every 48 h to establish pig iPS cells. The results showed that purified hOCT4/pSox2/pMyc/pKlf4-R9-EGFP fusion proteins could enter into PFF efficiently, and most of them were located in nuclei. The PPF were subcultured in stem cell medium condition and treated with defined factors recombinant proteins for 6 cycles simultaneously; the clear-cut cell colonies were gradually derived. These cells had large translucent nuclei and a high nucleo:cytoplasmic ratio and were positive for AP, Oct4, and Nanog. Detailed characterisation of such induced cells is ongoing. This research would provide new ideas for the induction of porcine somatic cell reprogramming. Y. H. Zhang and H. G. Cao contributed equally. This work was supported by NSFC (30700574 30800784/c120103) and 973 (2009CB941004).

Chromatin architecture reorganization during somatic cell reprogramming

2021 ◽  
Vol 70 ◽  
pp. 104-113
Author(s):  
Kun Zhao ◽  
Mingzhu Wang ◽  
Shaorong Gao ◽  
Jiayu Chen
Keyword(s):  
Somatic Cell ◽  
Cell Reprogramming ◽  
Chromatin Architecture ◽  
Somatic Cell Reprogramming

scholarly journals miR-6539 is a novel mediator of somatic cell reprogramming that represses the translation of Dnmt3b

2017 ◽  
Vol 63 (4) ◽  
pp. 415-423 ◽  
Author(s):  
Fujia WU ◽  
Li TAO ◽  
Shuai GAO ◽  
Likun REN ◽  
Zhuqing WANG ◽  
...  
Keyword(s):  
Somatic Cell ◽  
Cell Reprogramming ◽  
Somatic Cell Reprogramming
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