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- Cieślar-Pobuda, Artur, et al.
(författare)
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The expression pattern of PFKFB3 enzyme distinguishes between induced-pluripotent stem cells and cancer stem cells.
- 2015
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Ingår i: Oncotarget. - Albany, NY, USA : Impact Journals LLC. - 1949-2553. ; 6:30, s. 29753--29770
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Tidskriftsartikel (refereegranskat)abstract
- Induced pluripotent stem cells (iPS) have become crucial in medicine and biology. Several studies indicate their phenotypic similarities with cancer stem cells (CSCs) and a propensity to form tumors. Thus it is desirable to identify a trait which differentiates iPS populations and CSCs. Searching for such a feature, in this work we compare the restriction (R) point-governed regulation of cell cycle progression in different cell types (iPS, cancer, CSC and normal cells) based on the expression profile of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase3 (PFKFB3) and phosphofructokinase (PFK1). Our study reveals that PFKFB3 and PFK1 expression allows discrimination between iPS and CSCs. Moreover, cancer and iPS cells, when cultured under hypoxic conditions, alter their expression level of PFKFB3 and PFK1 to resemble those in CSCs. We also observed cell type-related differences in response to inhibition of PFKFB3. This possibility to distinguish CSC from iPS cells or non-stem cancer cells by PFKB3 and PFK1 expression improves the outlook for clinical application of stem cell-based therapies and for more precise detection of CSCs.
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| 2. |
- Shakeri, Raheleh, et al.
(författare)
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Role of the salt bridge between glutamate 546 and arginine 907 in preservation of autoinhibited form of Apaf-1
- 2015
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Ingår i: International Journal of Biological Macromolecules. - : ELSEVIER SCIENCE BV. - 0141-8130 .- 1879-0003. ; 81, s. 370-374
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Tidskriftsartikel (refereegranskat)abstract
- Apaf-1, the key element of apoptotic mitochondrial pathway, normally exists in an auto-inhibited form inside the cytosol. WRD-domain of Apaf-1 has a critical role in the preservation of auto-inhibited form; however the underlying mechanism is unclear. It seems the salt bridges between WRD and NOD domains are involved in maintaining the inactive conformation of Apaf-1. At the present study, we have investigated the effect of E546-R907 salt bridge on the maintenance of auto-inhibited form of human Apaf-1. E546 is mutated to glutamine (Q) and arginine (R). Over-expression of wild type Apaf-1 and its E546Q and E546R variants in HEK293T cells does not induce apoptosis unlike - HL-60 cancer cell line. In vitro apoptosome formation assay showed that all variants are cytochrome c and dATP dependent to form apoptosome and activate endogenous procaspase-9 in Apaf-1-knockout MEF cell line. These results suggest that E546 is not a critical residue for preservation of auto-inhibited Apaf-1. Furthermore, the behavior of Apaf-1 variants for in vitro apoptosome formation in HEK293T cell is similar to exogenous wild type Apaf-1. Wild type and its variants can form apoptosome in HEK293T cell with different procaspase-3 processing pattern in the presence and absence of exogenous cytochrome c and dATP. (C) 2015 Elsevier B.V. All rights reserved.
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| 3. |
- Vilas Jain, Mayur, et al.
(författare)
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Nuclear localized Akt enhances breast cancer stem-like cells through counter-regulation of p21(Waf1/Cip1) and p27(kip1)
- 2015
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Ingår i: Cell Cycle. - : Taylor and Francis: STM, Behavioural Science and Public Health Titles. - 1538-4101 .- 1551-4005. ; 14:13, s. 2109-2120
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Tidskriftsartikel (refereegranskat)abstract
- Cancer stem-like cells (CSCs) are a rare subpopulation of cancer cells capable of propagating the disease and causing cancer recurrence. In this study, we found that the cellular localization of PKB/Akt kinase affects the maintenance of CSCs. When Akt tagged with nuclear localization signal (Akt-NLS) was overexpressed in SKBR3 and MDA-MB468 cells, these cells showed a 10-15% increase in the number of cells with CSCs enhanced ALDH activity and demonstrated a CD44(+High)/CD24(-Low) phenotype. This effect was completely reversed in the presence of Akt-specific inhibitor, triciribine. Furthermore, cells overexpressing Akt or Akt-NLS were less likely to be in G0/G1 phase of the cell cycle by inactivating p21(Waf1/Cip1) and exhibited increased clonogenicity and proliferation as assayed by colony-forming assay (mammosphere formation). Thus, our data emphasize the importance the intracellular localization of Akt has on stemness in human breast cancer cells. It also indicates a new robust way for improving the enrichment and culture of CSCs for experimental purposes. Hence, it allows for the development of simpler protocols to study stemness, clonogenic potency, and screening of new chemotherapeutic agents that preferentially target cancer stem cells. Summary: The presented data, (i) shows new, stemness-promoting role of nuclear Akt/PKB kinase, (ii) it underlines the effects of nuclear Akt on cell cycle regulation, and finally (iii) it suggests new ways to study cancer stem-like cells.
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