Stromal Galectin-1 Promotes Colorectal Cancer Cancer-Initiating Cell Features and Disease Dissemination Through SOX9 and ß-Catenin: Development of Niche-Based Biomarkers.

Over 90% of colorectal cancer (CRC) patients have mutations in the Wnt/ß-catenin pathway, making the development of biomarkers difficult based on this critical oncogenic pathway. Recent studies demonstrate that CRC tumor niche-stromal cells can activate ß-catenin in cancer-initiating cells (CICs), leading to disease progression. We therefore sought to elucidate the molecular interactions between stromal and CRC cells for the development of prognostically relevant biomarkers. Assessment of CIC induction and ß-catenin activation in CRC cells with two human fibroblast cell-conditioned medium (CM) was performed with subsequent mass spectrometry (MS) analysis to identify the potential paracrine factors. In vitro assessment with the identified factor and in vivo validation using two mouse models of disease dissemination and metastasis was performed. Prediction of additional molecular players with Ingenuity pathway analysis was performed, with subsequent in vitro and translational validation using human CRC tissue microarray and multiple transcriptome databases for analysis. We found that fibroblast-CM significantly enhanced multiple CIC properties including sphere formation, ß-catenin activation, and drug resistance in CRC cells. MS identified galectin-1 (Gal-1) to be the secreted factor and Gal-1 alone was sufficient to induce multiple CIC properties in vitro and disease progression in both mouse models. IPA predicted SOX9 to be involved in the Gal-1/ß-catenin interactions, which was validated in vitro, with Gal-1 and/or SOX9-particularly Gal-1high/SOX9high samples-significantly correlating with multiple aspects of clinical disease progression. Stromal-secreted Gal-1 promotes CIC-features and disease dissemination in CRC through SOX9 and ß-catenin, with Gal-1 and SOX9 having a strong clinical prognostic value.

Luteolin suppresses androgen receptor-positive triple-negative breast cancer cell proliferation and metastasis by epigenetic regulation of MMP9 expression via the AKT/mTOR signaling pathway.

BACKGROUND: Triple-negative breast cancer (TNBC) represents up to 20% of all breast cancers. This cancer lacks the expression of the estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. The current therapeutic strategy for patients with this subtype is the use of cytotoxic chemotherapy and surgery. Luteolin is a natural herbal flavonoid and a potential therapeutic candidate for multiple diseases. The use of a treatment that combines Chinese herbal medicine and western medicine is rising in Asia. PURPOSE: The present study evaluates the effects and molecular mechanisms involved with luteolin treatment and evaluates whether this herb affects androgen receptor-positive breast cancer cell proliferation or metastasis. STUDY DESIGN: In vitro evaluation of the effect of luteolin on androgen receptor-positive TNBC cell proliferation and metastasis METHODS: Cell viability analysis was used for the cytotoxicity test. Colony formation and Bromodeoxyuridine (BrdU) staining-based proliferation experiments were used for cell proliferation. Wound healing and transwell assays were used for in vitro migration/invasion. The RT-qPCR analysis was used for gene expression. Furthermore, ChIP-qPCR analysis was used for epigenetic modification of gene promoters. RESULTS: Luteolin significantly inhibited the proliferation and metastasis of androgen receptor-positive TNBC. Furthermore, luteolin inactivated the AKT/mTOR signaling pathway and reversed the epithelial-mesenchymal transition (EMT). The combination of luteolin and inhibitors of AKT/mTOR synergistically repressed an androgen receptor-positive TNBC cell proliferation and metastasis. Luteolin also downregulated MMP9 expression by decreasing the levels of the AKT/mTOR promoting H3K27Ac and H3K56A on the MMP9 promoter region. CONCLUSION: Our findings indicate that luteolin inhibited the proliferation and metastasis of androgen receptor-positive TNBC by regulating MMP9 expression through a reduction in the levels of AKT/mTOR-inducing H3K27Ac and H3K56Ac.

Extracellular matrix protein laminin enhances mesenchymal stem cell (MSC) paracrine function through αvß3/CD61 integrin to reduce cardiomyocyte apoptosis.

Myocardial ischaemia (MI) results in extensive cardiomyocyte death and reactive oxygen species (ROS)-induced damage in an organ with little or no regenerative capacity. Although the use of adult bone marrow mesenchymal stem cells (BMMSCs) has been proposed as a treatment option, the high cell numbers required for clinical use are difficult to achieve with this source of MSCs, and animal studies have produced inconsistent data. We recently demonstrated in small and large animal models of acute MI that the application of human term placenta-derived multipotent cells (PDMCs), a foetal-stage MSC, resulted in reversal of cardiac injury with therapeutic efficacy. However, the mechanisms involved are unclear, making it difficult to strategize for therapeutic improvements. We found that PDMCs significantly reduced cardiomyocyte apoptosis and ROS production through the paracrine factors GRO-α, HGF and IL-8. Moreover, culturing PDMCs on plates coated with laminin, an extracellular matrix (ECM) protein, resulted in significantly enhanced secretion of all three paracrine factors, which further reduced cardiomyocyte apoptosis. The enhancement of PDMC paracrine function by laminin was mediated through αvß3 integrin, with involvement of the signalling pathways of JNK, for GRO-α and IL-8 secretion, and PI3K/AKT, for HGF secretion. Our results demonstrated the utility of PDMC therapy to reduce cardiomyocyte apoptosis through modulation of ECM proteins in in vitro culture systems as a strategy to enhance the therapeutic functions of stem cells.

Human pluripotent stem cell (PSC)-derived mesenchymal stem cells (MSCs) show potent neurogenic capacity which is enhanced with cytoskeletal rearrangement.

Mesenchymal stem cells (MSCs) are paraxial mesodermal progenitors with potent immunomodulatory properties. Reports also indicate that MSCs can undergo neural-like differentiation, offering hope for use in neurodegenerative diseases. However, ex vivo expansion of these rare somatic stem cells for clinical use leads to cellular senescence. A newer source of MSCs derived from human pluripotent stem cells (PSC) can offer the 'best-of-both-worlds' scenario, abrogating the concern of teratoma formation while preserving PSC proliferative capacity. PSC-derived MSCs (PSC-MSCs) also represent MSCs at the earliest developmental stage, and we found that these MSCs harbor stronger neuro-differentiation capacity than post-natal MSCs. PSC-MSCs express higher levels of neural stem cell (NSC)-related genes and transcription factors than adult bone marrow MSCs at baseline, and rapidly differentiate into neural-like cells when cultured in either standard neurogenic differentiation medium (NDM) or when the cytoskeletal modulator RhoA kinase (ROCK) is inhibited. Interestingly, when NDM is combined with ROCK inhibition, PSC-MSCs undergo further commitment, acquiring characteristics of post-mitotic neurons including nuclear condensation, extensive dendritic growth, and neuron-restricted marker expression including NeuN, ß-III-tubulin and Doublecortin. Our data demonstrates that PSC-MSCs have potent capacity to undergo neural differentiation and also implicate the important role of the cytoskeleton in neural lineage commitment.

Human Placenta-Derived Multipotent Cells (hPDMCs) Modulate Cardiac Injury: From Bench to Small and Large Animal Myocardial Ischemia Studies.

Cardiovascular disease is the leading cause of death globally, and stem cell therapy remains one of the most promising strategies for regeneration or repair of the damaged heart. We report that human placenta-derived multipotent cells (hPDMCs) can modulate cardiac injury in small and large animal models of myocardial ischemia (MI) and elucidate the mechanisms involved. We found that hPDMCs can undergo in vitro cardiomyogenic differentiation when cocultured with mouse neonatal cardiomyocytes. Moreover, hPDMCs exert strong proangiogenic responses in vitro toward human endothelial cells mediated by secretion of hepatocyte growth factor, growth-regulated oncogene-α, and interleukin-8. To test the in vivo relevance of these results, small and large animal models of acute MI were induced in mice and minipigs, respectively, by permanent left anterior descending (LAD) artery ligation, followed by hPDMC or culture medium-only implantation with follow-up for up to 8 weeks. Transplantation of hPDMCs into mouse heart post-acute MI induction improved left ventricular function, with significantly enhanced vascularity in the cell-treated group. Furthermore, in minipigs post-acute MI induction, hPDMC transplantation significantly improved myocardial contractility compared to the control group (p = 0.016) at 8 weeks postinjury. In addition, tissue analysis confirmed that hPDMC transplantation induced increased vascularity, cardiomyogenic differentiation, and antiapoptotic effects. Our findings offer evidence that hPDMCs can modulate cardiac injury in both small and large animal models, possibly through proangiogenesis, cardiomyogenesis, and suppression of cardiomyocyte apoptosis. Our study offers mechanistic insights and preclinical evidence on using hPDMCs as a therapeutic strategy to treat severe cardiovascular diseases.

Efficient derivation and concise gene expression profiling of human embryonic stem cell-derived mesenchymal progenitors (EMPs).

New potential sources of stem cells for clinical application include bone marrow mesenchymal stem cells (BMMSCs), human embryonic stem cells (hESCs), and induced pluripotent stem cells (iPS). However, each source is not without its own concerns. While research continues in an effort to overcome these problems, the generation of mesenchymal progenitors from existing hESC lines may circumvent many of these issues. We report here a simple and efficient method of generating hESC-derived mesenchymal progenitors (EMPs) and transcriptome profiling using a concise, custom-designed, oligomnucleotide gene expression microarray. Characterization of EMPs shows that these cells are similar to BMMSCs in terms of differentiation capacity as well as cell surface marker expression. In addition, EMPs express several ESC markers and HLA-G, a nonclassical MHC class I molecule with immunomodulatory properties. Morevoer, EMPs possess significantly enhanced proliferative ability over BMMSCs during which karyotypic stability was maintained. Although derived from hESCs, EMPs do not form any tumors in immunocompromised mice. To efficiently profile gene expression in multiple samples, we designed an oligoarray to probe just over 11,000 genes highly expressed in stem cells. We found that the transcriptome of EMPs is more similar to BMMSCs than hESCs. Both cell types highly express genes involved in processes related to the cytoskeleton, extracellular matrix, and cell adhesion, but EMPs show higher expression of genes involved in cell proliferation whereas BMMSCs showed higher expression of immune-related genes. Based on our data, EMPs may be an accessible source of mesenchymal progenitor for therapeutic use.