IL-6 secreted from senescent mesenchymal stem cells promotes proliferation and migration of breast cancer cells.

Human mesenchymal stem cells (hMSCs) are currently investigated for a variety of therapeutic applications. However, MSCs isolated from primary tissue cannot meet clinical grade needs and should be expanded in vitro for several passages. Although hMSCs show low possibility for undergoing oncogenic transformation, they do, similar to other somatic cells, undergo cellular senescence and their therapeutic potential is diminished when cultured in vitro. However, the role of senescent MSCs in tumor progression remains largely elusive. In the current study, by establishing senescent human umbilical cord mesenchymal stem cells (s-UCMSCs) through the replicative senescence model and genotoxic stress induced premature senescence model, we show that s-UCMSCs significantly stimulate proliferation and migration of breast cancer cells in vitro and tumor progression in a co-transplant xenograft mouse model compared with 'young' counterparts (defined as MSCs at passage 5, in contrast to senescent MSCs at passage 45). In addition, we identified IL-6, a known pleiotropic cytokine, as a principal mediator for the tumor-promoting activity of s-UCMSCs by induction of STAT3 phosphorylation. Depletion of IL-6 from s-UCMSCs conditioned medium partially abrogated the stimulatory effect of s-UCMSCs on the proliferation and migration of breast tumor cells

Recombinant Human HPS Protects Mice and Nonhuman Primates from Acute Liver Injury

Acute liver injury shares a common feature of hepatocytes death, immune system disorders, and cellular stress. Hepassocin (HPS) is a hepatokine that has ability to promote hepatocytes proliferation and to protect rats from D-galactose (D-Gal)- or carbon tetrachloride (CCl4)-induced liver injury by stimulating hepatocytes proliferation and preventing the high mortality rate, hepatocyte death, and hepatic inflammation. In this paper, we generated a pharmaceutical-grade recombinant human HPS using mammalian cells expression system and evaluated the effects of HPS administration on the pathogenesis of acute liver injury in monkey and mice. In the model mice of D-galactosamine (D-GalN) plus lipopolysaccharide (LPS)-induced liver injury, HPS treatment significantly reduced hepatocyte death and inflammation response, and consequently attenuated the development of acute liver failure. In the model monkey of D-GalN-induced liver injury, HPS administration promoted hepatocytes proliferation, prevented hepatocyte apoptosis and oxidation stress, and resulted in amelioration of liver injury. Furthermore, the primary pharmacokinetic study showed natural HPS possesses favorable pharmacokinetics; the acute toxicity study indicated no significant changes in behavioral, clinical, or histopathological parameters of HPS-treated mice, implying the clinical potential of HPS. Our results suggest that exogenous HPS has protective effects on acute liver injury in both mice and monkeys. HPS or HPS analogues and mimetics may provide novel drugs for the treatment of acute liver injury

s-UCMSCs promote migration and proliferation of breast cancer cells in vitro.

<p>(A) Transwell migration assay. Normal growth medium without cells was used as control. (B) Transmigrated cells were quantified. (C) Proliferation assay. All experiments were repeated at least three times. (*<i>P</i><0.05; **<i>P</i><0.01; ***<i>P</i><0.001).</p

IL-6/STAT-3 signal pathway contributes to the senescent MSCs stimulation of breast cancer cells growth and migration.

<p>(A) Protein level of IL-6, HGF, VEGF and TNF-α in the conditioned medium of senescent MSCs (P45-MSC and H₂O₂-MSC) and young counterparts (P5-MSC). (B) Proliferation assay. (C) Trans-migration assay of MDA-MB-231 cells and MCF-7 cells using control or IL-6-depleted H₂O₂-MSC conditioned medium. (D) Protein level of phosphorylated STAT3 upon treatment with H₂O₂-MSC conditioned medium with or without IL-6 specific antibody and Histograms show relative expression level from each group. All experiments were carried out at least three times. (*<i>P</i><0.05; ***<i>P</i><0.001).</p

Senescent MSCs stimulate growth and angiogenesis of breast tumor cells in vivo.

<p>Tumor volume (A) and final tumor weight (B) were measured as described. (C) Histology and immunohistochemistry for endothelin-1 in tumors derived after a 6-week injection with MDA-MB-231 cells or MDA-MB-231 plus H₂O₂-MSC or P5-MSC. (D) Quantification of endothelin-1-positive vessels from each tumor group (*<i>P</i><0.05; ***<i>P</i><0.001).</p

Characterization of s-UCMSCs.

<p>(A) Isolated UCMSCs were cultured under normal conditions for several passages until senescent (P45-MSC) or incubated for 2 h in the presence of 200 µM hydrogen peroxide. H₂O₂-MSC. The β-galactosidase positive stained cells were quantified as described in (B). (C) Flow-cytometry analysis of the cell cycle distribution of P5-MSC, P45-MSC and H₂O₂-MSC. (D) ALP, Oil-Red-O and Toluidine blue staining. Young counterparts (P5-MSC) were used as control.</p

Gene Expression Profiling in Human Fetal Liver and Identification of Tissue- and Developmental-Stage-Specific Genes through Compiled Expression Profiles and Efficient Cloning of Full-Length cDNAs

Fetal liver intriguingly consists of hepatic parenchymal cells and hematopoietic stem/progenitor cells. Human fetal liver aged 22 wk of gestation (HFL22w) corresponds to the turning point between immigration and emigration of the hematopoietic system. To gain further molecular insight into its developmental and functional characteristics, HFL22w was studied by generating expressed sequence tags (ESTs) and by analyzing the compiled expression profiles of liver at different developmental stages. A total of 13,077 ESTs were sequenced from a 3′-directed cDNA library of HFL22w, and classified as follows: 5819 (44.5%) matched to known genes; 5460 (41.8%) exhibited no significant homology to known genes; and the remaining 1798 (13.7%) were genomic sequences of unknown function, mitochondrial genomic sequences, or repetitive sequences. Integration of ESTs of known human genes generated a profile including 1660 genes that could be divided into 15 gene categories according to their functions. Genes related to general housekeeping, ESTs associated with hematopoiesis, and liver-specific genes were highly expressed. Genes for signal transduction and those associated with diseases, abnormalities, or transcription regulation were also noticeably active. By comparing the expression profiles, we identified six gene groups that were associated with different developmental stages of human fetal liver, tumorigenesis, different physiological functions of Itoh cells against the other types of hepatic cells, and fetal hematopoiesis. The gene expression profile therefore reflected the unique functional characteristics of HFL22w remarkably. Meanwhile, 110 full-length cDNAs of novel genes were cloned and sequenced. These novel genes might contribute to our understanding of the unique functional characteristics of the human fetal liver at 22 wk. [The sequence data described in this paper have been submitted to the GenBank data library under the accession nos. listed in Table 6 herein

TEM8 functions as a receptor for uPA and mediates uPA-stimulated EGFR phosphorylation

Abstract Background TEM8 is a cell membrane protein predominantly expressed in tumor endothelium, which serves as a receptor for the protective antigen (PA) of anthrax toxin. However, the physiological ligands for TEM8 remain unknown. Results Here we identified uPA as an interacting partner of TEM8. Binding of uPA stimulated the phosphorylation of TEM8 and augmented phosphorylation of EGFR and ERK1/2. Finally, TEM8-Fc, a recombinant fusion protein comprising the extracellular domain of human TEM8 linked to the Fc portion of human IgG1, efficiently abrogated the interaction between uPA and TEM8, blocked uPA-induced migration of HepG2 cells in vitro and inhibited the growth and metastasis of human MCF-7 xenografts in vivo. uPA, TEM8 and EGFR overexpression and ERK1/2 phosphorylation were found co-located on frozen cancer tissue sections. Conclusions Taken together, our data provide evidence that TEM8 is a novel receptor for uPA, which may play a significant role in the regulation of tumor growth and metastasis