Breast cancer, a stem cell disease.---from curr stem cell res ther.2008.
Breast cancer is a first magnitude problem of public health worldwide. There is increasing evidence that this cancer is originated in and maintained by a small population of undifferentiated cells with self-renewal properties. This small population generates a more differentiated pool of cells which represents the main mass of the tumor, resembling the hierarchical tissue organization of the normal breast. These cancer stem cells seem to share a similar phenotype with their normal counterparts but they display dysfunctional patterns of proliferation and differentiation, and they no longer respond to normal physiological controls that ensure a balanced cellular turnover. The origin of these cancer stem cells is controversial; it is not well known if they are originated from normal stem cells or from more differentiated progenitors where a de novo stem cell program is activated by the oncogenic insult. Here we review the origin of breast cancer stem cells and their role in the pathogenesis of cancer development, together with their implications in breast cancer progression, treatment and prognosis.
Saturday, February 23, 2008
Friday, February 22, 2008
Stem cells for myocardial regeneration--a hopeful therapy for heart attacks?
Cardiac myocyte progenitors from adult hearts for myocardial regenerative therapy.
Yang CF et al.
Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan, R.O.C.
Background: The heart is a highly vascular organ and prolonged interruption of myocardial blood flow initiates events that culminate in cardiac myocyte death. Proposed experimental reparative strategies include harvesting potent cells followed by direct injection into ischemic myocardium to achieve myogenesis and angiogenesis. Methods: Accordingly, we set out to isolate and expand a purified population of adult rat putative cardiomyocyte precursors, and to identify their characteristics in vitro. By using an acute myocardial infarction model and direct cell implantation, we further tested the hypothesis that these cells are an ideal cell source for myocardial regeneration and can enhance cardiac repair after implantation into the ischemic rat heart. Results: We describe here the identification of a subpopulation of primitive cells from rat heart, processing stem cell marker, c-kit and myogenic transcriptional factors, GATA-4 and MEF 2C, and cardiac specific proteins, troponin-I, alpha-sarcomeric actinin and connexin-43. They exhibited a high in vitro proliferative potential. These findings strongly suggest that these cells are putative cardiomyocyte precursors. After transplantation, they were able to be retained and proliferate (13.63 +/- 5.97% after 2 weeks) within the ischemic heart. Progeny of implanted cells migrated along the infarcted scar, reconstituted regenerated cardiomyocytes with incorporation into host myocardium, and inhibited cardiac remodeling with decreased scar formation. Conclusion: Our findings suggest that putative cardiomyocyte precursors isolated from adult heart could potentially be an autologous cell source for myocardial regeneration cell therapy.
Yang CF et al.
Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan, R.O.C.
Background: The heart is a highly vascular organ and prolonged interruption of myocardial blood flow initiates events that culminate in cardiac myocyte death. Proposed experimental reparative strategies include harvesting potent cells followed by direct injection into ischemic myocardium to achieve myogenesis and angiogenesis. Methods: Accordingly, we set out to isolate and expand a purified population of adult rat putative cardiomyocyte precursors, and to identify their characteristics in vitro. By using an acute myocardial infarction model and direct cell implantation, we further tested the hypothesis that these cells are an ideal cell source for myocardial regeneration and can enhance cardiac repair after implantation into the ischemic rat heart. Results: We describe here the identification of a subpopulation of primitive cells from rat heart, processing stem cell marker, c-kit and myogenic transcriptional factors, GATA-4 and MEF 2C, and cardiac specific proteins, troponin-I, alpha-sarcomeric actinin and connexin-43. They exhibited a high in vitro proliferative potential. These findings strongly suggest that these cells are putative cardiomyocyte precursors. After transplantation, they were able to be retained and proliferate (13.63 +/- 5.97% after 2 weeks) within the ischemic heart. Progeny of implanted cells migrated along the infarcted scar, reconstituted regenerated cardiomyocytes with incorporation into host myocardium, and inhibited cardiac remodeling with decreased scar formation. Conclusion: Our findings suggest that putative cardiomyocyte precursors isolated from adult heart could potentially be an autologous cell source for myocardial regeneration cell therapy.
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