Various family members are expressed in mESCs, hESCs and ECCs. Because they are not expressed on somatic cells, TRAs are useful markers for the isolation of human iPS cells during reprogramming.Ĭluster of differentiation antigens (CDs) are membrane proteins that function in diverse processes such as cell adhesion, communication and differentiation. These are proteoglycan epitopes that reside on the 200 kDa form of podocalyxin (SC-podocalyxin). Human ESC, embryonic carcinoma and germ tumors are characterized by the expression of tumor rejection antigens (TRA-1-60 and TRA-1-81). HESC: Human embryonic stem cell mESCs: Mouse embryonic stem cells SSEA: Stage specific embryonic antigens TRA: Tumor rejection antigens. Additionally, knowledge about their stem cell properties is valuable for the eradication of CSCs that are responsible for therapy resistance, tumor invasion and metastasis. This information can elucidate the risks stemming from the tumorigenic potential of pluripotent ESC and iPS cells used in tissue regeneration therapies. In this review, we analyze common regulatory mechanisms of embryonic and CSCs focusing on biomarkers, signaling pathways, transcription factors and epigenetic complexes. The CSC model ultimately links Cancer with Stem cell biology and provides a common framework that is proposed to account for all the properties of stem cells, regardless of their early or late developmental origin in normal or pathological states. In addition, CSCs from epithelial tumors also exhibit ESC-like signatures that include the oncogene c-Myc and factors important for pluripotency such as Sox2, Dnmt1, Cbx3 and HDAC1. The procedures of somatic cell reprogramming and CSC establishment are both dependent on transitions between epithelial and mesenchymal states (EMT/MET). Because these cells share these properties with the adult tissue stem cells from which they are likely derived they were termed cancer stem cells (CSCs). Currently, growing experimental evidence has revealed that tumors contain a variable number of cells that have self-renewal and partial differentiation capacities. Reprogramming of somatic cells into pluripotency by oncogenes like Myc and Klf4 suggest a strong link between pluripotency and tumorigenicity. Pluripotent ESCs have inherent tumorigenic potential and they generate benign tumors and teratomas when injected in immunodeficient mice. Due to their ability to give rise to any type of differentiated cells and tissues, both ES and iPS cells offer many opportunities for modeling human diseases and development of regenerative medicine.ĮSCs and tumor cells share many common properties exemplified by rapid proliferation, similar metabolic requirements and inhibition of differentiation. In the last decade the introduction in somatic cells of transcription factors (Oct4, Sox2, Klf4, c-Myc), microRNAs and small molecules allowed the generation of induced pluripotent stem (iPS) cells. The extended transcriptional network of ESCs is centered on the triad of master regulators of pluripotency Oct4, Sox2 and Nanog. The pluripotency of ESCs is determined by the concerted action of signaling pathways that respond to external stimuli, intrinsically expressed transcription factors and complexes that govern the epigenetic state. Mouse ESCs (mESCs) are isolated from day 3.5 blastocyst and possess ground state pluripotency whereas human ESCs (hESCs) are isolated from late blastocyst and correspond to the epiblast stem cells of the mouse. Embryonic stem cells (ESCs) have two unique properties, self-renewal and pluripotency.
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