Dongmei Lai

Enrichment of ovarian cancer stem-like cells is associated with epithelial to mesenchymal transition through an miRNA-activated AKT pathway.

Evidence has indicated that ovarian epithelial cancer‐type cells under serum‐free culture conditions can form spheroid cells and exhibit characteristics expected of cancer stem‐like cells (CSCs). However, the mechanism by which differentiated ovarian cancer cells acquire stem‐cell properties during CSC enrichment has needed to be elucidated. Recent studies have demonstrated that induction of epithelial to mesenchymal transition (EMT) can generate CSCs and be associated with tumour aggressiveness and metastasis.

Human endometrial mesenchymal stem cells restore ovarian function through improving the renewal of germline stem cells in a mouse model of premature ovarian failure

BackgroundHuman endometrial mesenchymal stem cells (EnSCs) derived from menstrual blood have mesenchymal stem/stromal cells (MSCs) characteristics and can differentiate into cell types that arise from all three germ layers. We hypothesized that EnSCs may offer promise for restoration of ovarian dysfunction associated with premature ovarian failure/insufficiency (POF/POI).MethodsMouse ovaries were injured with busulfan and cyclophosphamide (B/C) to create a damaged ovary mouse model. Transplanted EnSCs were injected into the tail vein of sterilized mice (Chemoablated with EnSCs group; nu2009=u200980), or culture medium was injected into the sterilized mice via the tail vein as chemoablated group (nu2009=u200980). Non-sterilized mice were untreated controls (nu2009=u200980). Overall ovarian function was measured using vaginal smears, live imaging, mating trials and immunohistochemical techniques.ResultsEnSCs transplantation increased body weight and improved estrous cyclicity as well as restored fertility in sterilized mice. Migration and localization of GFP-labeled EnSCs as measured by live imaging and immunofluorescent methods indicated that GFP-labeled cells were undetectable 48xa0h after cell transplantation, but were later detected in and localized to the ovarian stroma. 5’-bromodeoxyuridine (BrdU) and mouse vasa homologue (MVH) protein double-positive cells were immunohistochemically detected in mouse ovaries, and EnSC transplantation reduced depletion of the germline stem cell (GSCs) pool induced by chemotherapy.ConclusionEnSCs derived from menstrual blood, as autologous stem cells, may restore damaged ovarian function and offer a suitable clinical strategy for regenerative medicine.

Human amniotic epithelial cells can differentiate into granulosa cells and restore folliculogenesis in a mouse model of chemotherapy-induced premature ovarian failure.

IntroductionOvarian dysfunction frequently occurs in female cancer patients after chemotherapy, but human amniotic epithelial cells (hAECs) that can differentiate into cell types that arise from all three germ layers may offer promise for restoration of such dysfunction. Previous studies confirmed that hAECs could differentiate into cells that express germ cell-specific markers, but at this time hAECs have not been shown to restore ovarian function.MethodsTo model premature ovarian failure, hAECs infected with lenti-virus carrying green fluorescent protein were injected into the tail vein of mice sterilized with cyclophosphamide and busulphan. hAECs migrated to the mouse ovaries and overall ovarian function was measured using immunohistochemical techniques.ResultsSeven days to two months after hAECs transplantation, ovarian cells were morphologically restored in sterilized mice. Hemotoxylin and eosin staining revealed that restored ovarian cells developed follicles at all stages. No follicles were observed in control mice at the same time period. Immunostaining with anti-human antigen antibodies and pre-transplantation labeling with green fluorescent protein (GFP) revealed that the grafted hAECs survived and migrated to mouse ovary, differentiating into granulosa cells. Furthermore, the ovarian function marker, anti-Müllerian hormone, was evident in treated mouse ovaries after hAEC transplantation.ConclusionsIntravenously injected hAECs reached the ovaries of chemotherapy-treated mice and restored folliculogenesis, data which suggest promise for hAECs for promoting reproductive health and improving the quality of life for female cancer survivors.

Human amniotic fluid stem cells have a potential to recover ovarian function in mice with chemotherapy-induced sterility

BackgroundHuman amniotic fluid cells (hAFCs) may differentiate into multiple cell lineages and thus have a great potential to become a donor cell source for regenerative medicine. The ability of hAFCs to differentiate into germ cell and oocyte-like cells has been previously documented. Herein we report the potential use of hAFCs to help restore follicles in clinical condition involving premature ovarian failure.ResultsHuman amniotic fluid was obtained via amniocentesis, yielding a subpopulation of cloned hAFCs that was able to form embryoid bodies (EBs) and differentiate into three embryonic germ layers. Moreover, culture of EBs in medium containing human follicular fluid (HFF) or a germ cell maturation factor cocktail (FAC), expressed germ cells markers such as BLIMP1, STELLA, DAZL, VASA, STRA8, SCP3, SCP1, and GDF9. Furthermore, one cell line was grown from clone cells transfected with lentivirus-GFP and displaying morphological characteristics of mesenchymal cells, had the ability to restore ovarian morphology following cell injection into the ovaries of mice sterilized by intraperitoneal injection of cyclophosphamide and busulphan. Restored ovaries displayed many follicle-enclosed oocytes at all stages of development, but no oocytes or follicles were observed in sterilized mice whose ovaries had been injected with medium only (control). Notably, identification of GFP-labeled cells and immunostaining with anti–human antigen-specific antibodies demonstrated that grafted hAFCs survived and differentiated into granulosa cells which directed oocyte maturation. Furthermore, labeling of ovarian tissue for anti-Müllerian hormone expression, a functional marker of folliculogenesis, was strong in hAFCs-transplanted ovaries but inexistent in negative controls.ConclusionThese findings highlight the possibility of using human amniotic fluid-derived stem cells in regenerative medicine, in particular in the area of reproductive health.

Human ovarian cancer stem-like cells can be efficiently killed by γδ T lymphocytes

Ovarian cancer comprises a small population of cancer stem cells (CSCs) that are responsible for tumor maintenance and resistant to cancer therapies, it would be desirable to develop a therapy that could selectively target ovarian CSCs. Recently, cellular immune-based therapies have improved the prognosis of cancer patients clinically. In this study, we isolated a subset of ovarian cancer sphere cells that possess CSC properties and explored the cell cytotoxicity of γδ T cells to ovarian cancer sphere cells using a transwell cocultured cell system. The proliferation rate of the cancer sphere cells decreased to 40% after cocultured with γδ T cells. The γδ T cells increased the sensitivity of SK-OV-3 sphere cells to chemotherapeutic drugs. After the treatment of γδ T cells, the expression of stem cell marker genes decreased in sphere cells, while the expression of HLA-DR antigen on tumor cells was increased in a time-dependent manner. Further, γδ T cells induced G2/M phase cell cycle arrest and subsequent apoptosis in SK-OV-3 sphere cells. Xenograft mouse models demonstrated that γδ T cells dramatically reduced the tumor burden. Notably, the level of IL-17 production significantly increased after cocultured with γδ T cells. We conclude that γδ T cells may efficiently kill ovarian CSCs through IL-17 production and represent a promising immunotherapy for ovarian cancer.

Optimization of Culture Conditions to Support Undifferentiated Growth of Human Embryonic Stem Cells

Human embryonic stem cells (hESCs) are usually maintained in an undifferentiated state by coculture with mitomycin C-treated mouse embryonic fibroblasts (MEFs) as feeder cells in the presence of animal sera such as fetal bovine serum (FBS). Here, we use primary human amnion epithelial cells (hAECs) as feeder cells and human umbilical cord blood serum (CBS) as a replacement for FBS to support undifferentiated growth of hESCs. The 5 approximately 10-fold higher expression levels of ES cell markers including FGF, Oct-4, Nanog, Sox-2, Rex, and TERT were found in hESCs grown on hAECs compared with that on MEFs as measured by quantitative real-time polymerase chain reaction (PCR). By immunofluorescence, the expresisons of Oct-4 and Nanog is also higher in cells grown on hAECs than those on MEFs. Importantly, the ES cells grown on hAECs exhibit normal karyotypes on passage 25, thus ruling out the possibility of transformation. Using flow cytometry analysis, we show that both the ES cells grown on hAECs and MEFs have the same cell cycle distribution pattern. Further, hESCs cultured on hAECs for at least 20 passages could differentiate into three germ layers via teratoma formation. In addition, chromatin immunoprecipitation assay revealed that histone H3 is highly acetylated, and H3 lysine (K) 4 is hypermethylated at the Nanog locus and the Oct-4 locus in hESCs grown on hAECs. Conversely, hESCs grown on MEFs show histone deacetylation and H3-K4 demethylation. Taken together, these results suggest that hAECs supplemented with 10% CBS are suitable for hESC culture, and that this method may prove to be valuable for use in future regenerative therapies.

LKB1 Controls the Pluripotent State of Human Embryonic Stem Cells

Human embryonic stem cells maintained on human amniotic epithelial cells (hESCs(hAEC)) are better preserved in an undifferentiated state and express pluripotency genes Oct4, Nanog, and Sox2 at higher levels compared with growth on mitotically inactivated mouse embryonic fibroblasts (hESCs(MEF)). Here we report that this correlates with the absence of the tumor suppressor and metabolic balancer gene, LKB1 expression in hESCs(hAEC). RNA interference knockdown of LKB1 in hESCs(MEF) resulted in upregulation of pluripotency marker genes of Oct4 and Nanog, while downregulation of differentiation markers (Runx1, AFP, GATA, Brachyury, Sox17 and Nestin). As in somatic cells, LKB1 controls p21/WAF1 expression by promoter binding in hESCs(MEF). Our results suggested that the absence of LKB1-mediated signaling is an important determinant of feeder cell-mediated support of hESC renewal.

The marine-derived fungal metabolite, terrein, inhibits cell proliferation and induces cell cycle arrest in human ovarian cancer cells

The difficulties faced in the effective treatment of ovarian cancer are multifactorial, but are mainly associated with relapse and drug resistance. Cancer stem-like cells have been reported to be an important contributor to these hindering factors. In this study, we aimed to investigate the anticancer activities of a bioactive fungal metabolite, namely terrein, against the human epithelial ovarian cancer cell line, SKOV3, primary human ovarian cancer cells and ovarian cancer stem-like cells. Terrein was separated and purified from the fermentation metabolites of the marine sponge-derived fungus, Aspergillus terreus strain PF26. Its anticancer activities against ovarian cancer cells were investigated by cell proliferation assay, cell migration assay, cell apoptosis and cell cycle assays. The ovarian cancer stem-like cells were enriched and cultured in a serum-free in vitro suspension system. Terrein inhibited the proliferation of the ovarian cancer cells by inducing G2/M phase cell cycle arrest. The underlying mechanisms involved the suppression of the expression of LIN28, an important marker gene of stemness in ovarian cancer stem cells. Of note, our study also demonstrated the ability of terrein to inhibit the proliferation of ovarian cancer stem-like cells, in which the expression of LIN28 was also downregulated. Our findings reveal that terrein (produced by fermention) may prove to be a promising drug candidate for the treatment of ovarian cancer by inhibiting the proliferation of cancer stem-like cells.

Human amniotic epithelial cells inhibit granulosa cell apoptosis induced by chemotherapy and restore the fertility

IntroductionPremature ovarian failure and insufficiency are significant long-term side-effects of chemotherapy for female cancer patients. Recently, stem cell transplantation has been identified as a promising treatment for premature ovarian failure and insufficiency. We have previously demonstrated that human amniotic epithelial cells (hAECs) migrate into injured tissue and promote the recovery of ovarian function in chemoablated mice. However, the molecular mechanism guiding this process remains unclear.MethodsTo further investigate the effect of hAECs on chemotherapy-induced apoptosis, cultured primary hAECs were injected intravenously into mice treated with cyclophosphamide and busulphan. Apoptosis of granulosa cells was observed by TUNEL staining, and apoptosis-related gene expression was performed on ovarian tissue by real-time PCR and Western blot 7 days after hAEC transplantation. Additionally, the ovarian function and fertility of mice were assessed via counts of follicles and mating experiments at 4 weeks after hAEC transplantation.ResultshAECs significantly inhibited tumor necrosis factor-alpha-mediated granulosa cell apoptosis induced by chemotherapeutics and reduced the inflammatory reaction in ovaries at 7 days after transplantation. In addition, 4 weeks after transplantation, hAECs promoted the development of follicles and increased the number of cumulus oocyte complexes in chemoablated mice. Furthermore, hAECs improved ovarian mass and increased the number of follicles compared to those of the chemoablated group, and hAEC transplantation partially rescued the fertility of chemoablated mice.ConclusionshAEC transplantation promotes ovarian function by inhibiting tumor necrosis factor-alpha-mediated cell apoptosis and reducing inflammation in chemotherapy-induced premature ovarian failure. These results suggest a potential molecular mechanism for the effective therapy of hAEC transplantation in chemotherapy-induced premature ovarian failure and insufficiency.

Mouse Primed Embryonic Stem Cells Could Be Maintained and Reprogrammed on Human Amnion Epithelial Cells

Naïve and primed embryonic stem cells (ESCs) represent 2 pluripotent states of mouse embryonic stem cells (mESCs), corresponding to the pre- and postimplantation cells, respectively, in vivo. Primed ESCs are distinct from naïve cells in biological characteristics, genetic features, developing potentials, and antagonistic signal pathway dependences to support undifferentiated growth. In vitro, naïve mESCs are readily converted to primed cells upon transferring to primed pluripotency signaling. ESC-derived epiblast stem cells (ESD-EpiSCs) are stabilized primed cells derived from naïve mESCs in vitro, and cannot be maintained with leukemia inhibitory factor (LIF) signaling with or without mouse embryonic fibroblasts as the feeder layer. Here, we show that the undifferentiated growth of ESD-EpiSCs could be maintained with the basic fibroblast growth factor employing human amnion epithelial cells (hAECs) as the feeder layer. Upon exposure to LIF, ESD-EpiSCs could undergo a reprogramming process on hAECs and be converted to naïve-like cells converted ESCs (cESCs), in which naïve pluripotency markers were activated, and primed markers were suppressed. DNA methylation analysis also validated the epigenetic conversion from primed to naïve-like pluripotent status. The bone morphogenetic protein 4 (BMP4) is an important signaling factor in pluripotency controlling, germ cell development, and neural commitment. It showed that ESD-EpiSCs and cESCs exhibited different features toward BMP4. Our results prove that hAECs are ideal feeder cells for both naïve and primed ESCs. More importantly, the primed ESCs are allowed to be reprogrammed to naïve-like pluripotent cells on hAECs. These findings suggest that under suitable conditions primed ESCs have the potency of converting to naïve-like ESCs.