Induction of embryonic stem cells to hematopoietic cells in vitro

In order to get hematopoietic cells from embryonic stem (ES) cells and to study development mechanisms of hematopoietic cells, the method of inducing embryonic stem cells to hematopoietic cells was explored by differenciating mouse ES cells and human embryonic cells in three stages. The differentiated cells were identified by flow cytometry, immunohistochemistry and Wright's staining. The results showed that embryoid bodies (EBs) could form when ES cells were cultured in the medium with 2-mercaptoethanol (2-ME). However, cytokines, such as stem cell factor (SCF), thrombopoietin (TPO), interleukin-3 (IL-3), interleukin-6 (IL-6), erythropoietin (EPO) and granular colony stimulating factor (G-CSF), were not helpful for forming EBs. SCF, TPO and embryonic cell conditional medium were useful for the differentiation of mouse EBs to hematopoietic progenitors. Eighty-six percent of these cells were CD34+ after 6-d culture. Hematopoietic progenitors differentiated to B lymphocytes when they were cocultured with primary bone marrow stroma cells in the DMEM medium with SCF and IL-6. 14 d later, most of the cells were CD34-CD38+. Wright's staining and immunohistochemistry showed that 80% of these cells were plasma-like morphologically and immunoglubolin positive. The study of hematopoietic cells from human embryonic cells showed that human embryonic cell differentiation was very similar to that of mouse ES cells. They could form EBs in the first stage and the CD34 positive cells account for about 48.5% in the second stage.     

CTAB调控乳腺癌干细胞抑制迁移

乳腺癌转移是限制其临床治疗的主要因素.十六烷基三甲基溴化铵(CTAB)作为一种潜在的抗癌化合物具有明显的抗肿瘤作用.使用划痕和Transwell实验证明了CTAB可抑制ZR-75-1细胞迁移.乳腺癌干细胞是导致乳腺癌转移的一个重要因素.通过免疫荧光、流式细胞术和细胞成球实验证明CTAB降低了乳腺癌干细胞比例,并且抑制了干性标记物CD44和CD133的表达.实验证明CTAB抑制乳腺癌干细胞并且抑制乳腺癌细胞迁移.     

Advances in studies on hepatic stem cells

The question whether hepatic stem cells exist or not has been debated for several decades. Current researches confirm that there are hepatic stem cells in the liver. Oval cells, putative bipotential hepatic stem cells, are probably located within canals of Hering, portal tracts or branches of biliary trees. Bone marrow is a potential source of oval cells, indicating that there exists a close relationship between liver and hematopoiesis in adulthood. Hepatic stem cells are able to proliferate in vitro and can be induced to differentiate into hepatocytes. This will provide a promising approach of cell transplantation, tissue engineering and gene therapy for liver diseases. In this review, the evidence of their presence, origin, identification, proliferation in vitro, differentiation by induction, application prospects of hepatic stem cells and future directions for the field are discussed.     

Induction of embryonic stem cells to hematopoietic cellsin vitro

In order to get hematopoietic cells from embryonic stem (ES) cells and to study development mechanisms of hematopoietic cells, the method of inducing embryonic stem cells to hematopoietic cells was explored by differenciating mouse ES cells and human embryonic cells in three stages. The differentiated cells were identified by flow cytometry, immunohistochemistry and Wright’s staining. The results showed that embryoid bodies (EBs) could form when ES cells were cultured in the medium with 2-mercaptoethanol (2-ME). However, cytokines, such as stem cell factor (SCF), thrombopoietin (TPO), interleukin-3 (IL-3), interleukin-6 (IL-6), erythropoietin (EPO) and granular colony stimulating factor (G-CSF), were not helpful for forming EBs. SCF, TPO and embryonic cell conditional medium were useful for the differentiation of mouse EBs to hematopoietic progenitors. Eighty-six percent of these cells were CD34⁺ after 6-d culture. Hematopoietic progenitors differentiated to B lymphocytes when they were cocultured with primary bone marrow stroma cells in the DMEM medium with SCF and IL-6. 14 d later, most of the cells were CD34^－CD38⁺. Wright’s staining and immunohistochemistry showed that 80% of these cells were plasma-like morphologically and immunoglubolin positive. The study of hematopoietic cells from human embryonic cells showed that human embryonic cell differentiation was very similar to that of mouse ES cells. They could form EBs in the first stage and the CD34 positive cells account for about 48.5% in the second stage.     

Distinct stem cells contribute to mammary gland development and maintenance

The mammary epithelium is composed of several cell lineages including luminal, alveolar and myoepithelial cells. Transplantation studies have suggested that the mammary epithelium is maintained by the presence of multipotent mammary stem cells. To define the cellular hierarchy of the mammary gland during physiological conditions, we performed genetic lineage-tracing experiments and clonal analysis of the mouse mammary gland during development, adulthood and pregnancy. We found that in postnatal unperturbed mammary gland, both luminal and myoepithelial lineages contain long-lived unipotent stem cells that display extensive renewing capacities, as demonstrated by their ability to clonally expand during morphogenesis and adult life as well as undergo massive expansion during several cycles of pregnancy. The demonstration that the mammary gland contains different types of long-lived stem cells has profound implications for our understanding of mammary gland physiology and will be instrumental in unravelling the cells at the origin of breast cancers.