Establishing clonal cell lines with endothelial-like potential from CD9(hi), SSEA-1(-) cells in embryonic stem cell-derived embryoid bodies

PRSS1 Mutations Affect Pancreatic Ductal Adenocarcinoma Radiosensitivity via AKT and Extracellular Regulated Protein Kinases Pathways

Radioresistance is the leading cause of failed radiation therapy for pancreatic ductal cancer (PDAC). The relevance of the cationic trypsinogen gene (PRSS1) in PDAC radioresistance is unknown, despite its association with tumor responses to therapy in numerous malignancies. Here we established two PRSS1 point mutation PDAC cell lines: c. 338 T > G and c.410 C > T. Compared to their parental cells, elevated AKT and ERK phosphorylation concentrations were observed in Panc-1 and MIA PaCa-2 c. 338 T > G and c.410 C > T cells with point mutations. The PRSS1 mutation restored the sensitivity of radioresistant cells to radiation through increased ionizing radiation-induced apoptosis by down regulating p-AKT and p-ERK. Based on these results, we hypothesized that a PRSS1 mutation in PDAC increased cell radiosensitivity by decreasing p-AKT and p-ERK. Our findings provide a molecular basis for optimizing radiation in patients with PDAC.

Nano-Albumin Particles Loaded with miR-20a Inhibitor Targeting Met Protein to Reverse Proliferation of Intestinal Cancer Cells

This study explored miR-20a’s role in intestinal cancer cells. SW480 cell line was divided into control group, agonist group, inhibitor group, and negative control group, followed by analysis of cell proliferation, apoptosis, Met, Bad, and Bcl-2 protein expressions. Results showed that miR-20a expression in the agonist group was the highest, followed by blank group and negative control group, and inhibitor group was lowest. S-phase and G2/M cell number from inhibitor group was lowest, and cell apoptosis rate was highest. However, the agonist group showed contrary changes. There was no difference in G0/G1 phase cell number among the four groups (P > 0.05). Moreover, the expressions of Bad, Bcl-2, Met, Wnt, β-catenin, and p-Wnt in inhibitor group were all lower, while the expressions in agonist group were all high (P < 0.05). S-phase and G2/M cell number in inhibitor group was lowest, while cell apoptosis was highest. The agonist group was opposite, with G0/G1 phase cells in each group showing no difference (P > 0.05). Wnt, β-catenin, and p-Wnt expressions were lowest in the inhibitor group, while the agonist group was opposite. These results together showed that the miR-20a directly targeted and regulated Met protein. Finally, the miR-20a inhibited intestinal cancer cell proliferation mainly through inhibiting Wnt/β-catenin signaling activity.

Improved cell survival and paracrine capacity of human embryonic stem cell-derived mesenchymal stem cells promote therapeutic potential for pulmonary arterial hypertension

Although transplantation of adult bone marrow mesenchymal stem cells (BM-MSCs) holds promise in the treatment for pulmonary arterial hypertension (PAH), the poor survival and differentiation potential of adult BM-MSCs have limited their therapeutic efficiency. Here, we compared the therapeutic efficacy of human embryonic stem cell-derived MSCs (hESC-MSCs) with adult BM-MSCs for the treatment of PAH in an animal model. One week following monocrotaline (MCT)-induced PAH, mice were randomly assigned to receive phosphate-buffered saline (MCT group); 3.0×10(6) human BM-derived MSCs (BM-MSCs group) or 3.0×10(6) hESC-derived MSCs (hESC-MSCs group) via tail vein injection. At 3 weeks post-transplantation, the right ventricular systolic pressure (RVSP), degree of RV hypertrophy, and medial wall thickening of pulmonary arteries were lower=, and pulmonary capillary density was higher in the hESC-MSC group as compared with BM-MSC and MCT groups (all p < 0.05). At 1 week post-transplantation, the number of engrafted MSCs in the lungs was found significantly higher in the hESC-MSC group than in the BM-MSC group (all p < 0.01). At 3 weeks post-transplantation, implanted BM-MSCs were undetectable whereas hESC-MSCs were not only engrafted in injured pulmonary arteries but had also undergone endothelial differentiation. In addition, protein profiling of hESC-MSC- and BM-MSC-conditioned medium revealed a differential paracrine capacity. Classification of these factors into bioprocesses revealed that secreted factors from hESC-MSCs were preferentially involved in early embryonic development and tissue differentiation, especially blood vessel morphogenesis. We concluded that improved cell survival and paracrine capacity of hESC-MSCs provide better therapeutic efficacy than BM-MSCs in the treatment for PAH.

The human nose harbors a niche of olfactory ectomesenchymal stem cells displaying neurogenic and osteogenic properties

We previously identified multipotent stem cells within the lamina propria of the human olfactory mucosa, located in the nasal cavity. We also demonstrated that this cell type differentiates into neural cells and improves locomotor behavior after transplantation in a rat model of Parkinson's disease. Yet, next to nothing is known about their specific stemness characteristics. We therefore devised a study aiming to compare olfactory lamina propria stem cells from 4 individuals to bone marrow mesenchymal stem cells from 4 age- and gender-matched individuals. Using pangenomic microarrays and immunostaining with 34 cell surface marker antibodies, we show here that olfactory stem cells are closely related to bone marrow stem cells. However, olfactory stem cells also exhibit singular traits. By means of techniques such as proliferation assay, cDNA microarrays, RT-PCR, in vitro and in vivo differentiation, we report that when compared to bone marrow stem cells, olfactory stem cells display (1) a high proliferation rate; (2) a propensity to differentiate into osseous cells; and (3) a disinclination to give rise to chondrocytes and adipocytes. Since peripheral olfactory stem cells originate from a neural crest-derived tissue and, as shown here, exhibit an increased expression of neural cell-related genes, we propose to name them olfactory ectomesenchymal stem cells (OE-MSC). Further studies are now required to corroborate the therapeutic potential of OE-MSCs in animal models of bone and brain diseases.

Delineating biological pathways unique to embryonic stem cell-derived insulin-producing cell lines from their noninsulin-producing progenitor cell lines

To identify unique biochemical pathways in embryonic stem cell-derived insulin-producing cells as potential therapeutic targets to prevent or delay beta-cell dysfunction or death in diabetic patients, comparative genome-wide gene expression studies of recently derived mouse insulin-producing cell lines and their progenitor cell lines were performed using microarray technology. Differentially expressed genes were functionally clustered to identify important biochemical pathways in these insulin-producing cell lines. Biochemical or cellular assays were then performed to assess the relevance of these pathways to the biology of these cells. A total of 185 genes were highly expressed in the insulin-producing cell lines, and computational analysis predicted the pentose phosphate pathway (PPP), clathrin-mediated endocytosis, and the peroxisome proliferator-activated receptor (PPAR) signaling pathway as important pathways in these cell lines. Insulin-producing ERoSHK cells were more resistant to hydrogen peroxide (H(2)O(2))-induced oxidative stress. Inhibition of PPP by dehydroepiandrosterone and 6-aminonicotinamide abrogated this H(2)O(2) resistance with a concomitant decrease in PPP activity as measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Clathrin-mediated endocytosis, which is essential in maintaining membrane homeostasis in secreting cells, was up-regulated by glucose in ERoSHK but not in their progenitor ERoSH cells. Its inhibition by chlorpromazine at high glucose concentration was toxic to the cells. Troglitazone, a PPARG agonist, up-regulated expression of Ins1 and Ins2 but not Glut2. Gene expression analysis has identified the PPP, clathrin-mediated endocytosis, and the PPAR signaling pathway as the major delineating pathways in these insulin-producing cell lines, and their biological relevance was confirmed by biochemical and cellular assays.

PI3 K/Akt/mTOR-mediated translational control regulates proliferation and differentiation of lineage-restricted RoSH stem cell lines

BACKGROUND

We have previously derived highly similar lineage-restricted stem cell lines, RoSH and E-RoSH cell lines from mouse embryos and CD9hi SSEA-1- differentiated mouse embryonic stem cells, respectively. These cell lines are not pluripotent and differentiate readily into endothelial cells in vitro and in vivo.

RESULTS

We investigated the signaling pathway that maintains proliferation of these cells in an undifferentiated state, and demonstrate that PI3 K/Akt/mTOR, but not Raf/MEK/Erk, signaling in these cells was active during proliferation and was downregulated during endothelial differentiation. Inhibition of PI3 K/Akt/mTOR signaling, but not Raf/MEK/Erk, reduced proliferation and induced expression of endothelial specific proteins. During differentiation or inhibition of PI3 K/Akt/mTOR signaling, cyclinD2 transcript abundance in ribosome-enriched RNA but not in total RNA was reduced with a corresponding reduction in protein level. In contrast, transcript abundance of endothelial-specific genes e.g. Kdr, Tek and Pdgfralpha in ribosome-enriched RNA fraction was not reduced and their protein levels were increased. Together these observations suggested that translational control mediated by PI3K/Akt/mTOR signaling was critical in regulating proliferation and endothelial differentiation of lineage-restricted RoSH-like stem cell lines.

CONCLUSION

This study highlights translation regulation as a critical regulatory mechanism during proliferation and differentiation in stem cells.

The Stem Cell Identity of Testicular Cancer

Testicular germ cell tumors account for 1% of all cancers, and are the most common malignancies to affect males between the ages of 15 and 34. Understanding the pathogenesis of testis cancer has been challenging because the molecular and cellular events that result in the formation of germ cell tumors are hypothesized to occur during human fetal development. In this review, the molecular pathways involved in human testis cancer will be presented based on our research in human embryonic stem cells (hESCs), and also research using animal models. Testis germ cell tumors are unique in that the normal germ cell from which the tumor is derived has distinct stem cell characteristics that are shared with pluripotent hESCs. In particular, normal fetal germ cells express the core pluripotent transcription factors NANOG, SOX2 and OCT4. In contrast to hESCs, the germ line is not pluripotent. As a result, germ cell tumorigenesis may arise from loss of germ line-specific inhibitors which in normal germ cells prevent overt pluripotency and self-renewal and when absent in abnormal germ cells, result in the conversion to germ line cancer stem cells. At the conclusion of this review, a model for the molecular events involved in germ cell tumor formation and the relationship between germ cell tumorigenesis and stem cell biology will be presented.