Molecular characterization of oct4-expressing yolk sac endoderm stem cell lines.

The extraembryonic endoderm (XEN) defines the yolk sac, a set of membranes that provide essential support for mammalian embryos. Recently, the committed XENprecursor was identified in the embryonic Inner Cell Mass (ICM) as a group of cells that intermingles with the closely related, anatomically indistinguishable epiblast (EPI)- precursor that gives rise to the fetus. In vitro, the EPI-precursor is represented by the well-known embryonic stem (ES) cell lines, but cell lines representing the XENprecursor are not known. Furthermore, since the XEN-precursor cells were discovered only very recently, the unexpected fact that they express the key pluripotency marker Oct4 has not been explored. Recently, however, our laboratory has isolated rat XEN cell lines that express Oct4, leading to the following two questions: (i) Do these new XEN cell lines represent XEN-precursor cells? (ii) Is their Oct4 expression regulated similarly as previously known from ES cells? These two questions are addressed here by lineage marker and reporter gene analyses. Whole culture analyses showed that rat XEN cell lines expressed markers of all XEN stages including XEN-precursor, primitive endoderm (PrE) and/or visceral endoderm (VE), and parietal endoderm (PE) but trophoectoderm and EPI-precursor markers were missing. In line with this, immunocytochemistry demonstrated heterogeneity and directly visualized the XEN-precursor, PrE/VE, and PE subpopulations. Low-density plating and time-dependent immunocytochemistry on resulting colonies strongly suggested that XEN-precursor cells generate the other XEN stages. Moreover, by analyzing single-cell derived clones, it was shown that culture heterogeneity results from the self-renewal and differentiation of a single cell. Reporter gene analyses using the 5’ regulatory region of the mouse Oct4 gene revealed that a DNA fragment containing the previously described distal enhancer drove reporter gene expression only in ES cells whereas inclusion of an upstream fragment led to high expression in both mouse ES and rat XEN cells. In conclusion, our rat XEN cell lines contain XEN-precursor cells that differentiate extensively, providing for the first time an in vitro model that mimics the natural process of early XEN differentiation. In addition, they regulate Oct4 gene transcription differently than ES cells suggesting heterogeneous Oct4 regulation within the mammalian ICM

Soluble E-Cadherin and Regulation of ROS in Inflammatory

https://openworks.mdanderson.org/sumexp22/1085/thumbnail.jp

The Role of SGK1-NDRG1 Axis in Inflammatory Breast Cancer Stem Cells

https://openworks.mdanderson.org/sumexp23/1005/thumbnail.jp

Gender-Dependent Survival of Allogeneic Trophoblast Stem Cells in Liver

In view of the well-known phenomenon of trophoblast immune privilege, trophoblast stem cells (TSCs) might be expected to be immune privileged, which could be of interest for cell or gene therapies. Yet in the ectopic sites tested so far, TSC transplants fail to show noticeable immune privilege and seem to lack physiological support. However, we show here that after portal venous injection, green fluorescent protein (GFP)-labeled TSCs survive for several months in the livers of allogeneic female but not male mice. Gonadectomy experiments revealed that this survival does not require the presence of ovarian hormones but does require the absence of testicular factors. By contrast, GFP-labeled allogeneic embryonic stem cells (ESCs) are reliably rejected; however, these same ESCs survive when mixed with unlabeled TSCs. The protective effect does not require immunological compatibility between ESCs and TSCs. Tumors were not observed in animals with either successfully engrafted TSCs or coinjected ESCs. We conclude that in a suitable hormonal context and location, ectopic TSCs can exhibit and confer immune privilege. These findings suggest applications in cell and gene therapy as well as a new model for studying trophoblast immunology and physiology

Inflammatory breast cancer appearance at presentation is associated with overall survival

Background: Inflammatory breast cancer (IBC) is a clinical diagnosis. Here, we examined the association of a "classic" triad of clinical signs, swollen involved breast, nipple change, and diffuse skin change, with overall survival (OS). Method: Breast medical photographs from patients enrolled on a prospective IBC registry were scored by two independent reviewers as classic (triad above), not classic, and difficult to assign. Chi-squared test, Fisher's exact test, and Wilcoxon rank-sum test were used to assess differences between patient groups. Kaplan-Meier estimates and the log-rank test and Cox proportional hazard regression were used to assess the OS. Results: We analyzed 245 IBC patients with median age 54 (range 26-81), M0 versus M1 status (157 and 88 patients, respectively). The classic triad was significantly associated with smoking, post-menopausal status, and metastatic disease at presentation (p = 0.002, 0.013, and 0.035, respectively). Ten-year actuarial OS for not classic and difficult to assign were not significantly different and were grouped for further analyses. Ten-year OS was 29.7% among patients with the classic sign triad versus 57.2% for non-classic (p < 0.0001). The multivariate Cox regression model adjusting for clinical staging (p < 0.0001) and TNBC status (<0.0001) demonstrated classic presentation score significantly associated with poorer OS time (HR 2.6, 95% CI 1.7-3.9, p < 0.0001). Conclusions: A triad of classic IBC signs independently predicted OS in patients diagnosed with IBC. Further work is warranted to understand the biology related to clinical signs and further extend the understanding of physical examination findings in IBC

Isolation of Oct4-Expressing Extraembryonic Endoderm Precursor Cell Lines

BACKGROUND:The extraembryonic endoderm (ExEn) defines the yolk sac, a set of membranes that provide essential support for mammalian embryos. Recent findings suggest that the committed ExEn precursor is present already in the embryonic Inner Cell Mass (ICM) as a group of cells that intermingles with the closely related epiblast precursor. All ICM cells contain Oct4, a key transcription factor that is first expressed at the morula stage. In vitro, the epiblast precursor is most closely represented by the well-characterized embryonic stem (ES) cell lines that maintain the expression of Oct4, but analogous ExEn precursor cell lines are not known and it is unclear if they would express Oct4. METHODOLOGY/PRINCIPAL FINDINGS:Here we report the isolation and characterization of permanently proliferating Oct4-expressing rat cell lines ("XEN-P cell lines"), which closely resemble the ExEn precursor. We isolated the XEN-P cell lines from blastocysts and characterized them by plating and gene expression assays as well as by injection into embryos. Like ES cells, the XEN-P cells express Oct4 and SSEA1 at high levels and their growth is stimulated by leukemia inhibitory factor, but instead of the epiblast determinant Nanog, they express the ExEn determinants Gata6 and Gata4. Further, they lack markers characteristic of the more differentiated primitive/visceral and parietal ExEn stages, but exclusively differentiate into these stages in vitro and contribute to them in vivo. CONCLUSIONS/SIGNIFICANCE:Our findings (i) suggest strongly that the ExEn precursor is a self-renewable entity, (ii) indicate that active Oct4 gene expression (transcription plus translation) is part of its molecular identity, and (iii) provide an in vitro model of early ExEn differentiation

Mesenchymal Stem Cells Promote Mammosphere Formation and Decrease E-Cadherin in Normal and Malignant Breast Cells

Normal and malignant breast tissue contains a rare population of multi-potent cells with the capacity to self-renew, referred to as stem cells, or tumor initiating cells (TIC). These cells can be enriched by growth as "mammospheres" in three-dimensional cultures.We tested the hypothesis that human bone-marrow derived mesenchymal stem cells (MSC), which are known to support tumor growth and metastasis, increase mammosphere formation.We found that MSC increased human mammary epithelial cell (HMEC) mammosphere formation in a dose-dependent manner. A similar increase in sphere formation was seen in human inflammatory (SUM149) and non-inflammatory breast cancer cell lines (MCF-7) but not in primary inflammatory breast cancer cells (MDA-IBC-3). We determined that increased mammosphere formation can be mediated by secreted factors as MSC conditioned media from MSC spheroids significantly increased HMEC, MCF-7 and SUM149 mammosphere formation by 6.4 to 21-fold. Mammospheres grown in MSC conditioned media had lower levels of the cell adhesion protein, E-cadherin, and increased expression of N-cadherin in SUM149 and HMEC cells, characteristic of a pro-invasive mesenchymal phenotype. Co-injection with MSC in vivo resulted in a reduced latency time to develop detectable MCF-7 and MDA-IBC-3 tumors and increased the growth of MDA-IBC-3 tumors. Furthermore, E-cadherin expression was decreased in MDA-IBC-3 xenografts with co-injection of MSC.MSC increase the efficiency of primary mammosphere formation in normal and malignant breast cells and decrease E-cadherin expression, a biologic event associated with breast cancer progression and resistance to therapy

Preclinical Models of Brain Metastasis

Research at the Brain Metastasis Group is supported by MINECO grants MINECO-Retos SAF2017-89643-R (M.V.), Bristol-Myers Squibb- Melanoma Research Alliance Young Investigator Award 2017 (498103) (M.V.), Beug Foundation’s Prize for Metastasis Research 2017 (M.V.), Fundación Ramón Areces (CIVP19S8163) (M.V.), Worldwide Cancer Research (19-0177) (M.V.), H2020-FETOPEN (828972)N

Tetrandrine, a Compound Common in Chinese Traditional Medicine, Preferentially Kills Breast Cancer Tumor Initiating Cells (TICs) In Vitro

Tetrandrine is a bisbenzylisoquinoline alkaloid found in Stephania tetrandra, a Chinese medicine commonly used as an anti-inflammatory. It has extensive pharmacological activity, including positive ion channel blockade and inhibition of multiple drug resistance proteins. These activities are very similar to that of salinomycin, a known drug targeting breast cancer initiation cells (TICs). Herein, we tested tetrandrine targeting of breast cancer TICs. SUM-149, an inflammatory breast cancer cell line and SUM-159, a non-inflammatory metaplastic breast cancer cell line were used in these studies. In proliferation assays using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS), we found that the IC50 for inhibition of proliferation is 15.3 ± 4.1 µM for SUM-149 and 24.3 ± 2.1 µM for SUM-159 cells. Tetrandrine also inhibited mammosphere formation, a surrogate for breast cancer TICs growth in vitro with IC50 around 1 µM for SUM-149 and around 2 µM for SUM-159 cells. Tetrandrine has similar effects on the mammosphere formation from cells isolated from fresh patient sample. Moreover, tetrandrine decreases the aldehyde dehydrogenase (ALDH) positive population in SUM-159 by 45% ± 5.45% P = 0.005. In summary, tetrandrine demonstrates significant efficacy against in vitro surrogates for inflammatory and aggressive breast cancer TICs