Stem cells in adult tissues.
ABSTRACT In recent years the concept of a stem cell has evolved to encompass the hypotheses that stem cells exist within many adult tissues, and that a common 'interchangeable' progenitor cell may exist within the bone marrow capable of regenerating and repairing tissues throughout the body. As more knowledge is gained about stem cells, their potential roles in disease processes, including the development and progression of cancer, have moved to the forefront. The underlying hypothesis of this review is that cell fate is determined by a combination of intrinsic and extrinsic factors; growth and differentiation are regulated through intracellular integration of a multitude of signals initiated by internal and external stimuli. The development of successful stem cell based therapies may depend on experimental approaches that consider both the intrinsic and extrinsic factors that control cell fate.
- SourceAvailable from: Fatemeh Bagheri[Show abstract] [Hide abstract]
ABSTRACT: Received: 21/Dec/2008, Accepted: 22/Apr/2009 Regeneration of large bone defects is considered a challenging task by facio-mandibular and orthopedic surgeons. In these circumstances, either bone grafts or metal implants are currently being used. The inherent limitations associated with these methods have directed the attention of investigators to new technologies such as bone tissue engineering, a multi- disciplinary field in which life science as well as engineering is involved to manufacture an appropriate bone construct. The objectives of scientists involved in this field are to design and manufacture scaffolds with appropriate chemical and physical features, to direct cell dif- ferentiation within the scaffold using appropriate culture conditions and finally to render the engineered construct applicable for clinical use. In this article, the main components involved in the bone tissue engineering process have been reviewed. These include cells (with an emphasis on mesenchymal stem cells), scaffolds, growth factors and bioreactors, and tissue engineering approaches to tissue regeneration.
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ABSTRACT: Colorectal cancer is the third leading cause of cancer-related death in the western world. In vitro and in vivo experiments showed that omega-3 polyunsaturated fatty acids (n-3 PUFAs) can attenuate the proliferation of cancer cells, including colon cancer, and increase the efficacy of various anticancer drugs. However, these studies address the effects of n-3 PUFAs on the bulk of the tumor cells and not on the undifferentiated colon cancer stem-like cells (CSLCs) that are responsible for tumor formation and maintenance. CSLCs have also been linked to the acquisition of chemotherapy resistance and to tumor relapse. Colon CSLCs have been immunophenotyped using several antibodies against cellular markers including CD133, CD44, EpCAM, and ALDH. Anti-CD133 has been used to isolate a population of colon cancer cells that retains stem cells properties (CSLCs) from both established cell lines and primary cell cultures. We demonstrated that the n-3 PUFA, eicosapentaenoic acid (EPA), was actively incorporated into the membrane lipids of COLO 320 DM cells. 25 uM EPA decreased the cell number of the overall population of cancer cells, but not of the CD133 (+) CSLCs. Also, we observed that EPA induced down-regulation of CD133 expression and up-regulation of colonic epithelium differentiation markers, Cytokeratin 20 (CK20) and Mucin 2 (MUC2). Finally, we demonstrated that EPA increased the sensitivity of COLO 320 DM cells (total population) to both standard-of-care chemotherapies (5-Fluorouracil and oxaliplatin), whereas EPA increased the sensitivity of the CD133 (+) CSLCs to only 5-Fluorouracil.PLoS ONE 07/2013; 8(7):e69760. · 3.53 Impact Factor