Cancer stem cells (CSCs) are a promising target for treating cancer, yet how CSC plasticity is maintained in vivo is unclear and is difficult to study in vitro. Here we establish a sustainable primary culture of Oct3/4( þ )/Nanog( þ ) lung CSCs fed with CD90( þ ) cancer-associated fibroblasts (CAFs) to further advance our knowledge of preserving stem cells in the tumour microenvironment. Using transcriptomics we identify the paracrine network by which CAFs enrich CSCs through de-differentiation and reacquisition of stem cell-like properties. Specifically, we find that IGF1R signalling activation in cancer cells in the presence of CAFs expressing IGF-II can induce Nanog expression and promote stemness. Moreover, this paracrine signalling predicts overall and relapse-free survival in stage I non-small cell lung cancer (NSCLC) patients. IGF-II/IGF1R signalling blockade inhibits Nanog expression and attenuates cancer stem cell features. Our data demonstrate that CAFs constitute a supporting niche for cancer stemness, and targeting this paracrine signalling may present a new therapeutic strategy for NSCLC.

The type V TGF-beta receptor (TbetaR-V)/IGFBP-3 receptor mediates the IGF-independent growth inhibition induced by IGFBP-3. It also mediates the growth inhibitory response to TGF-beta1 in concert with other TGF-beta receptor types, and its loss may contribute to the malignant phenotype of human carcinoma cells. Here we demonstrate that TbetaR-V is identical to LRP-1/alpha2M receptor as shown by MALDI-TOF analysis of tryptic peptides of TbetaR-V purified from bovine liver. In addition, 125I-IGFBP-3 affinity-labeled TbetaR-V in Mv1Lu cells is immunoprecipitated by antibodies to LRP-1 and TbetaR-V. RAP, an LRP-1 antagonist, inhibits binding of 125I-TGF-beta1 and 125I-IGFBP-3 to TbetaR-V and diminishes IGFBP-3-induced growth inhibition in Mv1Lu cells. Absent or low levels of LRP-1, as with TbetaR-V, have been linked to the malignant phenotype of carcinoma cells. Mutagenized Mv1Lu cells selected for reduced expression of LRP-1 have an attenuated growth inhibitory response to TGF-beta1 and IGFBP-3. LRP-1-deficient mouse embryonic fibroblasts lack a growth inhibitory response to TGF-beta1 and IGFBP-3. On the other hand, stable transfection of H1299 human lung carcinoma cells with LRP-1 cDNA restores the growth inhibitory response. These results suggest that the LRP-1/TbetaR-V/IGFBP-3 receptor is required for the growth inhibitory response to IGFBP-3 and TGF-beta1.

In this study, we report a serum-free culture system for primary neonatal pulmonary cells that can support the growth of octamerbinding transcription factor 4 ؉ (Oct-4 ؉ ) epithelial colonies with a surrounding mesenchymal stroma. In addition to Oct-4, these cells also express other stem cell markers such as stage-specific embryonic antigen 1 (SSEA-1), stem cell antigen 1 (Sca-1), and Clara cell secretion protein (CCSP) but not c-Kit, CD34, and p63, indicating that they represent a subpopulation of Clara cells that have been implicated as lung stem͞progenitor cells in lung injury models. These colony cells can be kept for weeks in primary cultures and undergo terminal differentiation to alveolar type-2-and type-1-like pneumocytes sequentially when removed from the stroma.

Purpose: To unravel the role of interleukin (IL)-6 and insulinlike growth factor (IGF)-I receptor (IGFIR) in expressing stemnessrelated properties and to evaluate the prognostic values of pluripotent transcription factor OCT4/NANOG, and IGFIR in hepatocellular carcinoma (HCC).Experimental Design: Serum levels of IL6 were detected using ELISA assays (n ¼ 120). The effects of IL6/IGFI on stemness expression in HCC were examined using OCT4/ NANOG promoter luciferase reporter, RNA interference, secondary sphere formation, side population, and xenograft animal models. The OCT4/NANOG protein and phospho-IGFI receptor (p-IGFIR) in tissues were detected by Western blotting (n ¼ 8) and immunohistochemical staining (n ¼ 85). OCT4, NANOG, and IGFIR expression levels in tissues (n ¼ 191) were analyzed by real-time qRT-PCR and was correlated with early tumor recurrence using the Kaplan-Meier survival analysis.Results: A high positive correlation between the expression levels of OCT4/NANOG and IGFIR/p-IGFIR in human HCC tissues was observed. The concurrent expression of OCT4/ NANOG/IGFIR was mostly confined to hepatitis B virus (HBV)-related HCC (HBV-HCC) and was significantly correlated with early tumor recurrence. High serum levels of IL6 were significantly correlated with high OCT4/NANOG expression. IL6 stimulated an autocrine IGFI/IGFIR expression STAT3 dependently, which stimulated stemness-related properties in both the cell lines and the xenografted mouse tumors. The inhibition of IGFIR activation by either RNA interference or by treatment with the inhibitor picropodophyllin (PPP) significantly suppressed the IL6-induced stemness-related properties both in vitro and in vivo.Conclusions: The expression of pluripotency-related genes is associated with early tumor recurrence and is regulated by IL6-induced IGF/IGFIR activation, particularly in HBV-HCC.

Cell therapy is a promising strategy for the treatment of human diseases. While the first use of cells for therapeutic purposes can be traced to the 19th century, there has been a lack of general and reliable methods to study the biodistribution and associated pharmacokinetics of transplanted cells in various animal models for preclinical evaluation. Here, we present a new platform using albumin-conjugated fluorescent nanodiamonds (FNDs) as biocompatible and photostable labels for quantitative tracking of human placenta choriodecidual membrane-derived mesenchymal stem cells (pcMSCs) in miniature pigs by magnetic modulation. With this background-free detection technique and time-gated fluorescence imaging, we have been able to precisely determine the numbers as well as positions of the transplanted FND-labeled pcMSCs in organs and tissues of the miniature pigs after intravenous administration. The method is applicable to single-cell imaging and quantitative tracking of human stem/progenitor cells in rodents and other animal models as well.