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- Akrap, Nina, et al.
(författare)
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Identification of Distinct Breast Cancer Stem Cell Populations Based on Single-Cell Analyses of Functionally Enriched Stem and Progenitor Pools
- 2016
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Ingår i: Stem Cell Reports. - : Elsevier BV. - 2213-6711. ; 6:1, s. 121-136
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Tidskriftsartikel (refereegranskat)abstract
- The identification of breast cancer cell subpopulations featuring truly malignant stem cell qualities is a challenge due to the complexity of the disease and lack of general markers. By combining extensive single-cell gene expression profiling with three functional strategies for cancer stem cell enrichment including anchorage-independent culture, hypoxia, and analyses of low-proliferative, label-retaining cells derived from mammospheres, we identified distinct stem cell clusters in breast cancer. Estrogen receptor (ER)alpha+ tumors featured a clear hierarchical organization with switch-like and gradual transitions between different clusters, illustrating how breast cancer cells transfer between discrete differentiation states in a sequential manner. ER alpha- breast cancer showed less prominent clustering but shared a quiescent cancer stem cell pool with ER alpha+ cancer. The cellular organization model was supported by single-cell data from primary tumors. The findings allow us to understand the organization of breast cancers at the single-cell level, thereby permitting better identification and targeting of cancer stem cells.
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| 2. |
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| 3. |
- Kyttälä, Aija, et al.
(författare)
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Genetic Variability Overrides the Impact of Parental Cell Type and Determines iPSC Differentiation Potential.
- 2016
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Ingår i: Stem Cell Reports. - : Elsevier BV. - 2213-6711. ; 6:2, s. 200-212
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Tidskriftsartikel (refereegranskat)abstract
- Reports on the retention of somatic cell memory in induced pluripotent stem cells (iPSCs) have complicated the selection of the optimal cell type for the generation of iPSC biobanks. To address this issue we compared transcriptomic, epigenetic, and differentiation propensities of genetically matched human iPSCs derived from fibroblasts and blood, two tissues of the most practical relevance for biobanking. Our results show that iPSC lines derived from the same donor are highly similar to each other. However, genetic variation imparts a donor-specific expression and methylation profile in reprogrammed cells that leads to variable functional capacities of iPSC lines. Our results suggest that integration-free, bona fide iPSC lines from fibroblasts and blood can be combined in repositories to form biobanks. Due to the impact of genetic variation on iPSC differentiation, biobanks should contain cells from large numbers of donors.
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| 4. |
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| 5. |
- Morikawa, Masato, et al.
(författare)
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BMP Sustains Embryonic Stem Cell Self-Renewal through Distinct Functions of Different Kruppel-like Factors
- 2016
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Ingår i: Stem Cell Reports. - : Elsevier BV. - 2213-6711. ; 6:1, s. 64-73
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Tidskriftsartikel (refereegranskat)abstract
- Bone morphogenetic protein (BMP) signaling exerts paradoxical roles in pluripotent stem cells (PSCs); it sustains self-renewal of mouse embryonic stem cells (ESCs), while it induces differentiation in other PSCs, including human ESCs. Here, we revisit the roles of BMP-4 using mouse ESCs (mESCs) in naive and primed states. SMAD1 and SMAD5, which transduce BMP signals, recognize enhancer regions together with KLF4 and KLF5 in naive mESCs. KLF4 physically interacts with SMAD1 and suppresses its activity. Consistently, a subpopulation of cells with active BMP-SMAD can be ablated without disturbing the naive state of the culture. Moreover, Smad1/5 double-knockout mESCs stay in the naive state, indicating that the BMP-SMAD pathway is dispensable for it. In contrast, the MEK5-ERK5 pathway mediates BMP-4-induced self-renewal of mESCs by inducing Klf2, a critical factor for the ground state pluripotency. Our study illustrates that BMP exerts its self-renewing effect through distinct functions of different Kruppel-like factors.
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| 10. |
- Saxena, Shobhit, et al.
(författare)
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Cyclic AMP Signaling through Epac Axis Modulates Human Hemogenic Endothelium and Enhances Hematopoietic Cell Generation
- 2016
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Ingår i: Stem Cell Reports. - : Elsevier BV. - 2213-6711. ; 6:5, s. 692-703
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Tidskriftsartikel (refereegranskat)abstract
- Hematopoietic cells emerge from hemogenic endothelium in the developing embryo. Mechanisms behind human hematopoietic stem and progenitor cell development remain unclear. Using a human pluripotent stem cell differentiation model, we report that cyclic AMP (cAMP) induction dramatically increases HSC-like cell frequencies. We show that hematopoietic cell generation requires cAMP signaling through the Exchange proteins activated by cAMP (cAMP-Epac) axis; Epac signaling inhibition decreased both hemogenic and non-hemogenic endothelium, and abrogated hematopoietic cell generation. Furthermore, in hematopoietic progenitor and stem-like cells, cAMP induction mitigated oxidative stress, created a redox-state balance, and enhanced C-X-C chemokine receptor type 4 (CXCR4) expression, benefiting the maintenance of these primitive cells. Collectively, our study provides insights and mechanistic details on the previously unrecognized role of cAMP signaling in regulating human hematopoietic development. These findings advance the mechanistic understanding of hematopoietic development toward the development of transplantable human hematopoietic cells for therapeutic needs.
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