Oct4 mRNA Levels Research Articles

Histological and Molecular Biological Changes in Canine Skin Following Acute Radiation Therapy-Induced Skin Injury.

Radiation therapy is a crucial cancer treatment, but it can damage healthy tissues, leading to side effects like skin injuries and molecular alterations. This study aimed to elucidate histological and molecular changes in canine skin post-radiation therapy (post-RT) over nine weeks, focusing on inflammation, stem cell activity, angiogenesis, keratinocyte regeneration, and apoptosis. Four male beagles received a cumulative radiation dose of 48 Gy, followed by clinical observations, histological examinations, and an RT-qPCR analysis of skin biopsies. Histological changes correlated with clinical recovery from inflammation. A post-RT analysis revealed a notable decrease in the mRNA levels of Oct4, Sox2, and Nanog from weeks 1 to 9. VEGF 188 levels initially saw a slight increase at week 1, but they had significantly declined by week 9. Both mRNA and protein levels of COX-2 and Keratin 10 significantly decreased over the 9 weeks following RT, although COX-2 expression surged in the first 2 weeks, and Keratin 10 levels increased at weeks 4 to 5 compared to normal skin. Apoptosis peaked at 2 weeks and diminished, nearing normal by 9 weeks. These findings offer insights into the mechanisms of radiation-induced skin injury and provide guidance for managing side effects in canine radiation therapy.

Supplementing culture medium with the weak acid, 5,5-dimethyl-2,4-oxazolidinedione (DMO) limits the developmentof aneuploid mouse embryos through a Trp53-dependent mechanism.

This study was designed to determine if DMO limits in vitro development of aneuploid-enriched mouse embryos by activating a Trp53-dependent mechanism. Mouse cleavage-stage embryos were treated with reversine to induce aneuploidy or vehicle to generate controls, and then cultured in media supplemented with DMO to reduce the pH of the culture media. Embryo morphology was assessed by phase microscopy. Cell number, mitotic figures, and apoptotic bodies were revealed by staining fixed embryos with DAPI. mRNA levels of Trp53, Oct-4, and Cdx2 were monitored by quantitative polymerase chain reactions (qPCRs). The effect of Trp53 on the expression of Oct-4 and Cdx2 was assessed by depleting Trp53 using Trp53 siRNA. Aneuploid-enriched late-stage blastocysts were morphologically indistinguishable from control blastocysts but had fewer cells and reduced mRNA levels of Oct-4 and Cdx2. Adding 1mM DMO to the culture media during the 8-cell to blastocyst transition reduced the formation of aneuploid-enriched late-stage blastocysts but not control blastocysts and further suppressed the levels of Oct-4 and Cdx2 mRNA. Trp53 RNA levels in aneuploid-enriched embryos that were exposed to DMO were > twofold higher than controls, and Trp53 siRNA levels reduced the levels of Trp53 and increased levels of Oct-4 and Cdx2 mRNA by > twofold. These studies suggest that the development of morphologically normal aneuploid-enriched mouse blastocysts can be inhibited by adding low amounts of DMO to the culture media, which results in elevated levels of Trp53 mRNA that suppresses Oct-4 and Cdx2 expression.

Connexin46 Expression Enhances Cancer Stem Cell and Epithelial-to-Mesenchymal Transition Characteristics of Human Breast Cancer MCF-7 Cells.

Connexins (Cxs) are a family of proteins that form two different types of ion channels: hemichannels and gap junction channels. These channels participate in cellular communication, enabling them to share information and act as a synchronized syncytium. This cellular communication has been considered a strong tumor suppressor, but it is now recognized that some type of Cxs can be pro-tumorigenic. For example, Cx46 expression is increased in human breast cancer samples and correlates with cancer stem cell (CSC) characteristics in human glioma. Thus, we explored whether Cx46 and glioma cells, can set up CSC and epithelial-to-mesenchymal transition (EMT) properties in a breast cancer cell line. To this end, we transfected MCF-7 cells with Cx46 attached to a green fluorescent protein (Cx46GFP), and we determined how its expression orchestrates both the gene-expression and functional changes associated with CSC and EMT. We observed that Cx46GFP increased Sox2, Nanog, and OCT4 mRNA levels associated with a high capacity to form monoclonal colonies and tumorspheres. Similarly, Cx46GFP increased the mRNA levels of n-cadherin, Vimentin, Snail and Zeb1 to a higher migratory and invasive capacity. Furthermore, Cx46GFP transfected in MCF-7 cells induced the release of higher amounts of VEGF, which promoted angiogenesis in HUVEC cells. We demonstrated for the first time that Cx46 modulates CSC and EMT properties in breast cancer cells and thus could be relevant in the design of future cancer therapies.

Effects of ascites derived exosomes on the stemness and invasion ability of ovarian cancer stem-like cell

Objective: To investigate the effects of ovarian cancer ascites-derived exosomes on the stem cell properties and invasion ability of ovarian cancer stem-like cell (OCS-LC). Methods: (1) A2780 cells were induced into OCS-LC in serum-free medium, and authenticating their stem-like properties by sphere-forming test, differentiation test and CD133 marker detection. (2) Exosomes from ascites and A2780 cell were extracted by ultracentrifugation, then authenticating them. The morphology of exosomes was observed by the transmission electron microscope, exosome particle size was measured by nanoparticle tracking analysis (NTA). The expressions of heat shock protein 70 (HSP-70), CD63 and CD9 were detected by western blot. (3) The exosomes from ovarian cancer ascites and tumor cell supernate were co-cultured with OCS-LC. The groups were divided into control group, ascites-derived exosomes (ADE) group (ADE+OCS-LC group), and cells-derived exosomes (CDE) group (CDE+OCS-LC group). The sphere-forming ability was evaluated by sphere-forming cycle, maximum sphere diameter and sphere-forming rate of each group; the expression of CD133 was detected by immunofluorescence staining under microscope; quantitative real-time (qRT)-PCR was used to detected the expression levels of octamer-4 (Oct-4), Nanog mRNA of the signature genes in the stem cells of each group; the metastasis ability of each group was measured by transwell assay. Results: (1) Identification of OCS-LC: sphere-forming experiment showed that the suspension of OCSC single cells was grown in serum-free medium in secondary sphere-forming. Differentiation function experiment showed that OCS-LC were differentiated into adherent A2780 cells by changing the growth mode in serum containing medium. Flow cytometry showed that the proportion of CD133 positive (CD133+) cells in OCS-LC group was (18.9±0.9)%, significantly higher than that of control group (0.6±0.5)% (t=38.570, P<0.01). (2) Under transmission electron microscope, clear lipid bilayer structure was observed in ADE and CDE, and one side presented a concave hemispheric or cup like structure. NTA showed that the diameter of exosomes mainly ranged from 30 to 100 nm, with an average diameter of 67.2 nm. Western blot analysis showed that the specific protein molecules HSP-70, CD63 and CD9 were positive. (3) Three groups' OCS-LC could continue to grow into spheres, and the group of ADE+OCS-LC showed two growth modes, most of the cells continued to grow into spheres, while a small part of cells grew in adherent differentiation. The sphere-forming rate of OCS-LC in the control group, ADE+OCS-LC group, and CDE+OCS-LC group were (1.05±0.20)%, (4.15±0.10)%, and (10.45±0.25)%, the sphere-forming cycle of OCS-LC in the three groups were (15.3±1.5), (10.3±0.6), and (6.7±0.6) days, and the maximum diameters of OCS-LC were (100.3±3.2), (145.2±5.1) and (170.0±2.1) μm, respectively. And the differences were statistically significant (all P<0.05). After co-culture of exosomes with OCS-LC, the sphere-forming ability of cells in the group of CDE+OCS-LC was prior to ADE+OCS-LC group (all P<0.05). Immunofluorescence staining showed that the number of CD133 green fluorescent chromophore cells in OCS-LC groups [(46.2±2.1)%, (58.4±2.2)%] was significantly higher than that in the control group [(26.6±1.5)%] after the addition of exosomes in co-culture, the positive rate of CD133 was higher than that in the control group(F=187.588, P<0.05). The qRT-PCR results showed that the expression levels of Oct-4 mRNA in ADE+OCS-LC and CDE+OCS-LC groups were 3.46±0.24, 4.03±0.31, compared with that in control group (1.04±0.12), the differences were statistically significant (F=134.932, P<0.05). The mRNA expression levels of Nanog were 1.57±0.32, 2.66±0.15, which were significantly higher than that in the control group (1.00±0.07), and the differences were statistically significant (F=49.329, P<0.05). And the expression of both in CDE+OCS-LC group increased more significantly than ADE+OCS-LC group (all P<0.05). The number of invasive cells in the three groups of OCS-LC were: control group 30±5, ADE+OCS-LC group 102±4, CDE+OCS-LC group 210±7, and there were statistically significant differences among three groups (F=820.800, P<0.05). Compared with the control group, the number of invaded cells in the co-culture group were significantly increased (P<0.05), and the CDE+OCS-LC group had the higher cell invasion ability then the ADE+OCS-LC group (t=23.202, P<0.05). Conclusions: Exosomes derived from ovarian cancer ascites could enhance and maintain the stemness of OSC-LC, and promote the invasion of tumor cells. Moreover, CDE is superior to ADE.

Tryptophan and Kynurenine Enhances the Stemness and Osteogenic Differentiation of Bone Marrow-Derived Mesenchymal Stromal Cells In Vitro and In Vivo.

Aging tissues present a progressive decline in homeostasis and regenerative capacities, which has been associated with degenerative changes in tissue-specific stem cells and stem cell niches. We hypothesized that amino acids could regulate the stem cell phenotype and differentiation ability of human bone marrow-derived mesenchymal stromal cells (hBMSCs). Thus, we performed a screening of 22 standard amino acids and found that D-tryptophan (10 μM) increased the number of cells positive for the early stem cell marker SSEA-4, and the gene expression levels of OCT-4, NANOG, and SOX-2 in hBMSCs. Comparison between D- and L-tryptophan isomers showed that the latter presents a stronger effect in inducing the mRNA levels of Oct-4 and Nanog, and in increasing the osteogenic differentiation of hBMSCs. On the other hand, L-tryptophan suppressed adipogenesis. The migration and colony-forming ability of hBMSCs were also enhanced by L-tryptophan treatment. In vivo experiments delivering L-tryptophan (50 mg/kg/day) by intraperitoneal injections for three weeks confirmed that L-tryptophan significantly increased the percentage of cells positive for SSEA-4, mRNA levels of Nanog and Oct-4, and the migration and colony-forming ability of mouse BMSCs. L-kynurenine, a major metabolite of L-tryptophan, also induced similar effects of L-tryptophan in enhancing stemness and osteogenic differentiation of BMSCs in vitro and in vivo, possibly indicating the involvement of the kynurenine pathway as the downstream signaling of L-tryptophan. Finally, since BMSCs migrate to the wound healing site to promote bone healing, surgical defects of 1 mm in diameter were created in mouse femur to evaluate bone formation after two weeks of L-tryptophan or L-kynurenine injection. Both L-tryptophan and L-kynurenine accelerated bone healing compared to the PBS-injected control group. In summary, L-tryptophan enhanced the stemness and osteoblastic differentiation of BMSCs and may be used as an essential factor to maintain the stem cell properties and accelerate bone healing and/or prevent bone loss.

The DNMT1/miR-34a/FOXM1 Axis Contributes to Stemness of Liver Cancer Cells.

Background Whether DNA methyltransferase 1 (DNMT1)/miR-34a/FoxM1 signaling promotes the stemness of liver cancer stem cells (LCSCs) remains unclear. This study aimed to assess whether methylation-based silencing of miR-34a by DNMT1 contributes to stemness features via FoxM1 upregulation in LCSCs. Methods The CD133+ subgroup of MHCC97H cells sorted by MACS was used as LCSCs. DNMT1, BMI1, SOX2, and OCT4 mRNA levels, and miR-34a amounts were determined by qRT-PCR. DNMT1, CD44, and FoxM1 proteins were analyzed by immunoblot. Sphere and colony formation abilities were detected by respective assays. CD133+ cell percentages were assessed by flow cytometry. In vivo oncogenicity was evaluated using a tumor xenograft model in mice. The effects of DNMT1/miR-34a signaling on the stemness of LCSCs were examined by knockdown or overexpression of DNMT1 and/or transfection of miR-34a mimic or inhibitor using lentivirus-delivery systems. FoxM1 association with miR-34a was detected by a reporter assay. Results We here showed that LCSCs exhibited elevated DNMT1 activity and expression, lower miR-34a expression with higher promoter methylation, and stronger stemness, compared with the parental liver cancer cells. DNMT1 knockdown repressed DNMT1, increased miR-34a amounts by promoter demethylation, and reduced stemness in LCSCs, whereas DNMT1 overexpression had the opposite effects in liver cancer cells. Transfection with miR-34a mimic repressed the stemness of LCSCs, while miR-34a inhibitor significantly downregulated miR-34a and enhanced stemness, without affecting DNMT1 in liver cancer cells. MiR-34a mimic rescued the effects of DNMT1 overexpression on the stemness of LCSCs, without affecting DNMT1 expression. Finally, FOXM1 was identified as a direct target by miR-34a in LCSCs. Conclusions We revealed that aberrant activation of DNMT1 causes miR-34a promoter methylation and suppression, leading to FoxM1 upregulation by disinhibition and promotion of LCSC stemness. These findings suggest that blockage of DNMT1/miR-34a-mediated FOXM1 upregulation might suppress liver cancer by targeting LCSCs.

Impact of Viral Inflammation on the Expression of Renal Drug Transporters in Pregnant Rats.

Inflammation impacts the expression and function of drug transporters at term-gestation; however, the impact of inflammation on the expression of drug transporters at mid-gestation is largely unknown. Since renal drug transporters play a key role in the clearance of many drugs prescribed during pregnancy, our objective was to study the impact of the viral mimetic poly I:C on the expression of renal transporters in pregnant rats at mid-gestation. Poly I:C (10 mg/kg) or saline was administered intraperitoneally to pregnant Sprague–Dawley rats on gestational day 14. Expression of renal transporters was measured at 6, 24, and 48 h by qRT-PCR and Western blot. The mRNA levels of Mdr1a, Mrp4, Oct2, Octn1, Octn2, Mate1, Oat1-3, Urat1, Oatp4c1, Ent1, and Pept2 were significantly lower in the poly I:C group at 6 h. At 24 h, only the mRNA levels of Oct2, Oatp4c1, and Ent1 were decreased compared to saline. Poly I:C significantly decreased protein expression of Urat1 at 24 h, and P-gp, Oct2, Mate1, Oat1, Oat3 at 48 h,. Poly I:C imposed significant reductions in the expression of several key renal transporters at mid-gestation in pregnant rats. Thus, viral infection may impact renal excretion of drug transporter substrates, potentially leading to drug–disease interactions.

Sertoli cell-mediated differentiation of bovine fetal mesenchymal stem cells into germ cell lineage using an in vitro co-culture system

In vitro gamete derivation based on differentiation of germ cells (GC) from stem cells has emerged as a potential new strategy for the treatment of male infertility. This technology also has potential applications in animal reproduction as an alternative method for dissemination of elite animal genetics, production of transgenic animals, and conservation of endangered species. Mesenchymal stem cells (MSC) are multipotent progenitor cells defined by their ability to differentiate into mesodermal lineages. Under the effect of selected bioactive factors, MSC upregulate expression of pluripotent and GC specific-markers revealing their potential for GC differentiation. In addition to the effect of trophic factors, cell-to-cell interaction with Sertoli cells (SC) may be required to guide the sequential differentiation of MSC into GC. Thus, the aim of the present study was to investigate the effect of coculture with SC on the potential for in vitro GC differentiation of bovine fetal MSC (bfMSC) derived from bone marrow (BM-MSC) and adipose tissue (AT-MSC). bfMSC were isolated from male bovine fetuses and SC were collected from adult bull testes. The effect of SC interaction with BM-MSC or AT-MSC was analyzed on the expression of pluripotent factors OCT4 and NANOG, GC genes FRAGILLIS, STELLA and VASA and male GC markers DAZL, PIWIL2, STRA8 and SCP3 at Day 14 of coculture. Flow cytometry analyses detected that the majority (95,5% ± 2.5; P < 0.05) of the isolated population of SC cultures were positive for SC-specific marker WT1. Levels of mRNA of WT1 in BM-MSC and AT-MSC were lower (P < 0.05) compared to SC; whereas, WT1 expression was not detected in bovine fetal fibroblasts (FB). Cocultures of BM-MSC and AT-MSC with SC had higher (P < 0.05) OCT4 mRNA levels compared to monocultures of BM-MSC, AT-MSC and SC. Moreover, cocultures of BM-MSC with SC had higher (P < 0.05) proportion of cells positive for Oct4 and Nanog compared to monocultures of BM-MSC and SC. Levels of mRNA of DAZL, PIWIL2 and SCP3 were upregulated in cocultures of AT-MSC with SC compared to monocultures of AT-MSC and SC. Accordingly, the proportion of cells positive for Dazl were higher (P < 0.05) in cocultures of AT-MSC with SC compared to monocultures of AT-MSC and SC. Changes in gene expression profiles during coculture of SC with AT-MSC suggest that cell-to-cell interaction or bioactive factors provided by SC may induce progression of AT-MSC into early stages of GC differentiation.

Effect of zinc-finger binding protein-89 on the stemness of liver cancer cells by inhibiting octamer binding transcription factor 4 pathway

Objective To investigate the effect of zinc-finger binding protein-89 (ZBP-89) on octamer binding transcription factor 4 (Oct4) signaling pathway and liver cancer stemness. Methods Immunohistochemical staining was used to detect the expression of ZBP-89, CD133 and epithelial cell adhesion molecule (EpCAM) in 120 cases of hepatocellular carcinoma (HCC), and the correlation between ZBP-89 expression and CD133 and EpCAM was analyzed. The expression of ZBP-89 in Hep3B cells was regulated by ZBP-89 overexpressing lentiviral vector and small interfering RNA (siRNA), and the expression of Oct4, CD133 and EpCAM was detected by real-time quantitative polymerase chain reaction (Real-time PCR) and Western blotting. Results The expression of ZBP-89 was negatively correlated with the expression of CD133 and EpCAM in HCC tissues (χ2=45.000, P<0.05; χ2=26.020, P<0.05). When the expression of ZBP-89 in Hep3B cells was increased, the expression of Oct4, CD133 and EpCAM decreased, and the mRNA levels of Oct4, CD133 and EpCAM were (0.47±0.03), (0.63±0.01) and (0.53±0.02) times of the control group respectively (all P<0.05). When the expression of ZBP-89 decreased, the expression of Oct4, CD133 and EpCAM increased, and the mRNA levels of Oct4, CD133 and EpCAM were (2.04±0.03), (1.62±0.03) and (1.79±0.05) times of the control group respectively (all P<0.05). The results of Western blotting were consistent with the results of Real-time PCR. Conclusion ZBP-89 can inhibit the stemness of liver cancer cells by inhibiting the Oct4 signaling pathway. Key words: Zinc-finger binding protein-89; Octamer binding transcription factor 4; Hepatocellular carcinoma; Epithelial cell adhesion molecule; CD133

PO-292 Breast cancer stem cell reprogramming: deciphering the impact of glucose and the contribute of tumour microenvironment

IntroductionDiabetes-associated hyperglycemia is linked to poorer prognosis and survival in breast cancer (BC). Indeed, glucose can affect both tumour and tumour-surrounding cells. BC cells are embedded in an adipocyte-rich microenvironment, which, beside adipocytes, contains Stromal-Vascular Fraction Cells (SVFCs). In this scenario, epithelial and stromal compartments communicate through the release of soluble factors and establish an intricate crosstalk. Here, we analysed whether glucose could directly affect the phenotype of ER+ MCF7 BC cells and interfere with their interaction with adipose-derived SVFCs, thereby promoting tumour progression.Material and methodsMCF7 cell stemness markers were measured by qReal-Time PCR. Adipose-derived (Ad-)SVFCs were obtained by mammary adipose tissue specimens of women undergoing plastic surgery. The trascriptome of MCF7 exposed to either low (LG-5.5 mM) or high glucose concentration (HG-25 mM) was obtained by RNA-Sequencing (Illumina HiSeq3000).Results and discussionsHG exposure of MCF7 determined a significant increase of SOX2 mRNA levels as compared to LG, suggesting the induction of stemness programming. Co-culture with Ad-SVFCs in HG increased SOX2, NANOG and OCT4 mRNA levels in MCF7, as compared to isolated culture, indicating the involvement of SVF-produced soluble factors in BC stem cell reprogramming. Moreover, in presence of Ad-SVFCs and HG, MCF7 produced a higher number of mammospheres, which also displayed larger size. However, both in LG and in HG, conditioned media (CM) obtained from Ad-SVFCs produced no relevant effect on MCF7 stemness. Nevertheless, when Ad-SVFCs were pre-incubated with CM obtained from HG-treated MCF7, their CM very effectively increased OCT4, NANOG and SOX2 mRNA levels in MCF7. Thus, HG likely perturbs MCF7, which produce soluble factors leading Ad-SVFCs to release, in turn, reprogramming factors for BC cell stemness. In this regard, we have observed that HG modification of MCF7 transcriptome includes deregulation of 17 genes (pval=0.05) encoding for secreted proteins involved in cancer progression-related pathways, which may potentially play a role in tumour-stroma interactions.ConclusionGlucose affects BC stem cell reprogramming both directly and through Ad-SVFCs. Deciphering the mechanisms that govern this intricate crosstalk will pave the way to new targeted strategies to improve BC control in conditions of metabolic derangement.

Targeting High‐Mobility Group Box2 by miR‐127 Modulates Pluripotency of Mouse Embryonic Stem Cells and Contributes to Aggressiveness of Hepatocellular Carcinoma

BackgroundCancer progenitor cells possess some characteristics associated with normal stem cells. MiR‐127 is associated with germ layer differentiation and its promoter is hypermethylated in cancer cells. High‐mobility‐group protein 2 (HMGB2) is highly expressed in embryonic stage and hepatocellular carcinoma (HCC), but low in adult liver. The current study aimed at elucidating a novel regulation of HMGB2 by miR‐127 in mouse stem cells and liver cancer disease.MethodsMouse ESCs (CGR8, Sigma) were maintained on 0.1% gelatin coated dish in Knockout DMEM containing 15% ES‐FBS, 2 mM L‐glutamin, 0.1 mM NEAA, 0.1 mM β‐mercaptoethanol 50 μg/ml penicillin‐streptomycin and 10 ng/ml Leukemia inhibitory factor (LIF). For embryonic body (EB) formation, ESCs were trypsinized into single cells and cultured by seeding 900 ESCs in 30 μl hanging droplets of ES medium devoid of LIF. Liver tumor initiating cells (TICs) spheroid assay: 1000 cells were suspended in serum free TIC medium with 1% methylcellulose supplemented with B27, 20 ng/ml EGF and 20 ng/ml FGF in each well of 96‐well ultralow attachment plate for 7 days. Other methods: luciferase reporter assay, qPCR, Western blots, Co‐immunoprecipitation (Co‐IP), cell invasion, shRNA knockdown and adenovirus overexpression.ResultsThe level of miR‐127 was markedly elevated in CGR8 cells during EB differentiation, which correlated with the significant down‐regulation of HMGB2, OCT4 and SOX2. A conserved seed region for miR‐127 exists in the 3′UTR of human, mouse and rat HMBG2 genes. Ectopic expression of miR‐127 inhibited HMGB2 3′UTR activity in a dose dependent manner, which was abolished by mutation of the miR‐127 seed region and miR‐127 antagomir (anti‐miR‐127). Ectopic expression of miR‐127 reduced HMGB2 protein levels in a variety of human HCC cells. HMGB2 interacted with OCT4 and increased protein levels of OCT4 and SOX2, which further enhanced their transcriptional activity. On the other hand, HMGB2 inhibitor Inflachromene (ICM) induced differentiation of mouse stem cells and alleviated proliferation of TIC cells. Ectopic expression of miR‐127 in mouse stem cell reduced mRNA levels of Oct4, Nanog and Sox2, but increased mesendoderm markers during EB formation. Ectopic expression of miR‐127 in TIC cells lead to smaller spheroid formation, which was rescued by HMGB2. This was associated with decreased RhoA, CDC42, and Rac1/2/3 expression by miR‐127.ConclusionmiR‐127 is a novel regulator of mouse stem cell differentiation and liver cancer progenitor cell proliferation by targeting HMGB2. Our work provides a therapeutic perspective for future translational studies to inhibit HCC metastasis by blocking HMGB2.Support or Funding InformationGrant support: NIH R01DK104656, R01DK080440, R01ES025909, R21AA022482, R21AA024935, VA Merit Award 1I01BX002634.

Abstract 1052: Stearoyl-CoA-Desaturase (SCD1) regulates lung cancer stemness via stabilization and nuclear localization of YAP/TAZ

Abstract One of the most common traits of cancer is the radical change of cellular metabolism. A distinctive aspect of this altered metabolic status is the presence of a larger pool of monounsaturated fatty acids (MUFA), the precursors of the components of cell membranes necessary to sustained the rapidly dividing cancer cells. MUFA are largely generated from saturated fatty acids by the action of the two Stearoyl-CoA desaturases isoforms, namely SCD1 and SCD5. Recent evidences suggest that the major isoform SCD1 plays a role in several cancers. Our group has previously reported, using primary adenocarcinoma cell lines from malignant pleural effusions, that SCD1 inhibition selectively kills ALDH positive cells, a marker of cancer stem cells, causes spheroid 3D cultures collapse in vitro and impairs their growth in vivo. These results suggest that SCD1 may be a critical target in lung cancer tumor-initiating cells and further studies are needed to assess the role of this enzyme in lung cancer. An increasing number of literature points to the Hippo (and their effectors YAP/ TAZ) and to the Wnt/β-catenin signaling pathways as key factors in the development of cancer. Notably, SCD1 has been shown to be involved in the secretion and maturation of active wnt ligands, contributing to the activation of the β-catenin signaling. We report here, using primary cell cultures from adenocarcinoma of the lung, that YAP and TAZ are required for the generation of 3D cultures, as silencing of both genes completely abrogated the capability of generating lung cancer spheroids. Moreover, simultaneously silencing of YAP and TAZ reduced the mRNA levels of OCT4, Nanog and ALDH. We demonstrated that both silencing of SCD1 and its pharmacological inhibition determined a decrease in the expression and nuclear localization of both YAP and TAZ. Moreover, when SCD1 was inhibited, YAP and TAZ transcriptional activity was reduced. We also demonstrated that SCD1 blockade induced a dramatic reduction of the Axin2 mRNA level, one of the β-catenin target genes and a decreased in the β-catenin transcriptional activity, without affecting β-catenin protein expression. YAP and TAZ downregulation induced by SCD1 blockade could be rescued by the addition of exogenous wnt3a ligand, thus indicating that the active β-catenin signaling is necessary for YAP and TAZ stabilization. Ultimately, we observed that the ubiquitin ligase β-TrcP is involved in the SCD1 mediated degradation of YAP and TAZ. These data, overall, demonstrate for the first time the involvement of SCD1 in the regulation of the Hippo pathway and β-catenin pathway in lung cancer 3D spheroid cultures, pointing to lipid metabolism as regulator of cancer stem features. Moreover, these results can be the starting point for further studies focused on the regulation of SCD1 in cancer stem cells, suggesting a new perspective for improving chemotherapeutic responses in cancer treatment, centered on SCD1 inhibition. Citation Format: Alessia Noto, Maria Elena Pisanu, Claudia De Vitis, Giovanni Sorrentino, Giannino Del Sal, Alfredo Budillon, Gennaro Ciliberto, Rita Mancini. Stearoyl-CoA-Desaturase (SCD1) regulates lung cancer stemness via stabilization and nuclear localization of YAP/TAZ. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1052.

Exposure of Somatic Cells to Cytoplasm Extracts of Porcine Oocytes Induces Stem Cell-Like Colony Formation and Alters Expression of Pluripotency and Chromatin-Modifying Genes.

Cell permeabilization followed by exposure to cytoplasmic extracts of oocytes has been proposed as an alternative to transduction of transcription factors for inducing pluripotency in cultured somatic cells. The main goal in this study was to investigate the effect of treating porcine fibroblast cells with cytoplasmic extracts of GV-stage oocyte (OEx) followed by inhibition of histone deacetylases with Scriptaid (Scrip) on the formation of stem cell-like colonies and expression of genes encoding pluripotency and chromatin-modifying enzymes. Stem cell-like colonies start developing ∼2 weeks after treatment in cells exposed to OEx or OEx + Scrip. The number of cell colonies at the first day of appearance and 48 hours later was also similar between OEx and OEx + Scrip treatments. Transcripts for Nanog, Rex1, and c-Myc genes were detected in most cell samples that were analyzed on different days after OEx treatment. However, Sox2 transcripts were not detected and only a small proportion of samples had detectable levels of Oct4 mRNA after OEx treatment. A similar pattern of transcripts for pluripotency genes was observed in cells treated with OEx alone or OEx + Scrip. Transcript levels for Dnmt1 and Ezh2 were reduced at Day 3 after treatment in cells exposed to OEx. These findings revealed that: (a) exposure to OEx can induce a partial reprogramming of fibroblast cells toward pluripotency, characterized by colony formation and activation of pluripotency genes; and (b) inhibition of histone deacetylases does not improve the reprogramming effect of OEx treatment.

Follistatins have potential functional role in Porcine Embryogenesis

In animal reproduction, the quality of oocytes and embryos has been evaluated by the expression of specific molecules. Follistatin (FST), which was isolated from follicular fluid, binds and bio-neutralizes the TGF-β superfamily members. Previous studies using the bovine model showed FST could be an important molecular determinant of embryo developmental competence. However, the effect of FST treatment on porcine embryo developmental competence has not been established. In this study, the effect of exogenous FST on porcine embryo developmental competence was investigated during in vitro culture. FST (10 ng/ml) treatment induced a significant decrease in the rate of cell arrest at the 4-cell stage. The expression levels of DNA-methyltransferase 1 (DNMT1), histone deacetylase 1 (HDAC1), and histone deacetylase 2 (HDAC2) were decreased in 4-cell stage embryos. FST treatment also resulted in significant improvements in developmental competence of embryos in terms of blastocyst formation rate and OCT-4 mRNA levels, the latter being related to pluripotency. In conclusion, during in vitro culture, FST treatment significantly ameliorated 4-cell block during embryonic development and improved embryo developmental competence. Therefore, FST treatment may potentially have a functional role in porcine embryogenesis that is broadly applicable to enhance in vitro embryo development.

Liver receptor homolog 1 influences blastocyst hatching in pigs.

Liver receptor homolog 1 (Lrh1, also known as Nr5a2) belongs to the orphan nuclear receptor superfamily and has diverse functions in development, metabolism, and cell differentiation and death. Lrh1 regulates the expression of Oct4, which is a key factor of early embryonic differentiation. However, the role of Lrh1 in early development of mammalian embryo is unknown. In the present study, the localization, Lrh1 mRNA expression, and LRH1 protein levels in porcine early parthenotes were examined by immunofluorescence and real-time reverse-transcription polymerase chain reaction. To determine the role of Lrh1 in porcine early embryo development, the parthenotes were treated with the specific LRH1 antagonist 505601. The immunofluorescence signal for LRH1 was only observed in the nucleus of blastocysts. The blastocyst developmental rate in the presence of 50 and 100 μM 505601 was significantly lower than that in the control group. The blastocyst hatching rate was also reduced in the presence of 50 and 100 μM 505601 than that under control conditions. The latter effect was possibly due to the decreased expression of hatching-related genes such as Fn1, Itgα5, and Cox2 upon the inhibition of Lrh1. Incubation with the LRH1 antagonist also increased the number of apoptotic cells among the blastocysts. Moreover, LRH1 inhibition enhanced the expression of the pro-apoptotic genes Bax and Casp3, and reduced the expression of the anti-apoptotic gene Bcl2. Lrh1 inhibition also led to significant decrease in the expression levels of Oct4 mRNA and octamer-binding transcription factor 4 (OCT4) protein in the blastocysts. In conclusion, Lrh1 affects blastocyst formation and hatching in porcine embryonic development through the regulation of OCT4 expression and cell apoptosis.

CRISPR/Cas9 as tool for functional study of genes involved in preimplantation embryo development.

The CRISPR/Cas9 system has proven to be an efficient gene-editing tool for genome modification of cells and organisms. However, the applicability and efficiency of this system in pig embryos have not been studied in depth. Here, we aimed to remove porcine OCT4 function as a model case using the CRISPR/Cas9 system. Injection of Cas9 and single-guide RNA (sgRNA) against OCT4 decreased the percentages of OCT4-positive embryos to 37–50% of total embryos, while ~100% of control embryos exhibited clear OCT4 immunostaining. We assessed the mutation status near the guide sequence using polymerase chain reaction (PCR) and DNA sequencing, and a portion of blastocysts (20% in exon 2 and 50% in exon 5) had insertions/deletions near protospacer-adjacent motifs (PAMs). Different target sites had frequent deletions, but different concentrations of sgRNA made no impact. OCT4 mRNA levels dramatically decreased at the 8-cell stage, and they were barely detectable in blastocysts, while mRNA levels of other genes, including NANOG, and CDX2 were not affected. In addition, the combination of two sgRNAs led to large-scale deletion (about 1.8 kb) in the same chromosome. Next, we injected an enhanced green fluorescent protein (eGFP) vector targeting the OCT4 exon with Cas9 and sgRNA to create a knockin. We confirmed eGFP fluorescence in blastocysts in the inner cell mass, and also checked the mutation status using PCR and DNA sequencing. A significant portion of blastocysts had eGFP sequence insertions near PAM sites. The CRISPR/CAS9 system provides a good tool for gene functional studies by deleting target genes in the pig.

Transcriptional regulatory events initiated by Ascl1 and Neurog2 during neuronal differentiation of P19 embryonic carcinoma cells.

As members of the proneural basic-helix-loop-helix (bHLH) family of transcription factors, Ascl1 and Neurog2 direct the differentiation of specific populations of neurons at various times and locations within the developing nervous system. In order to characterize the mechanisms employed by these two bHLH factors, we generated stable, doxycycline-inducible lines of P19 embryonic carcinoma cells that express comparable levels of Ascl1 and Neurog2. Upon induction, both Ascl1 and Neurog2 directed morphological and immunocytochemical changes consistent with initiation of neuronal differentiation. Comparison of Ascl1- and Neurog2-regulated genes by microarray analyses showed both shared and distinct transcriptional changes for each bHLH protein. In both Ascl1- and Neurog2-differentiating cells, repression of Oct4 mRNA levels was accompanied by increased Oct4 promoter methylation. However, DNA demethylation was not detected for genes induced by either bHLH protein. Neurog2-induced genes included glutamatergic marker genes while Ascl1-induced genes included GABAergic marker genes. The Neurog2-specific induction of a gene encoding a protein phosphatase inhibitor, Ppp1r14a, was dependent on distinct, canonical E-box sequences within the Ppp1r14a promoter and the nucleotide sequences within these E-boxes were partially responsible for Neurog2-specific regulation. Our results illustrate multiple novel mechanisms by which Ascl1 and Neurog2 regulate gene repression during neuronal differentiation in P19 cells.

The effects of triclosan on pluripotency factors and development of mouse embryonic stem cells and zebrafish.

Triclosan (TCS) poses potential risks to reproduction and development due to its endocrine-disrupting properties. However, the mechanism of TCS's effects on early embryonic development is little known. Embryonic stem cells (ESC) and zebrafish embryos provide valuable models for testing the toxic effects of environmental chemicals on early embryogenesis. In this study, mouse embryonic stem cells (mESC) were acutely exposed to TCS for 24 h, and general cytotoxicity and the effect of TCS on pluripotency were then evaluated. In addition, zebrafish embryos were exposed to TCS from 2- to 24-h post-fertilization (hpf), and their morphology was evaluated. In mESC, alkaline phosphatase staining was significantly decreased after treatment with the highest concentration of TCS (50 μM). Although the expression levels of Sox2 mRNA were not changed, the mRNA levels of Oct4 and Nanog in TCS-treated groups were significantly decreased compared to controls. In addition, the protein levels of Oct4, Sox2 and Nanog were significantly reduced in response to TCS treatment. MicroRNA (miR)-134, an expression inhibitor of pluripotency markers, was significantly increased in TCS-treated mESC. In zebrafish experiments, after 24 hpf of treatment, the controls had developed to the late stage of somitogenesis, while embryos exposed to 300 μg/L of TCS were still at the early stage of somitogenesis, and three genes (Oct4, Sox2 and Nanog) were upregulated in treated groups when compared with the controls. The two models demonstrated that TCS may affect early embryonic development by disturbing the expression of the pluripotency markers (Oct4, Sox2 and Nanog).

A short-term treatment with tumor necrosis factor-alpha enhances stem cell phenotype of human dental pulp cells

IntroductionDuring normal pulp tissue healing, inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α) or interleukins, act in the initial 48 hours (inflammatory phase) and play important roles not only as chemo-attractants of inflammatory cells and stem/progenitor cells but also in inducing a cascade of reactions toward tissue regeneration or reparative dentin formation or both. Previous reports have shown that inflammatory cytokines regulate the differentiation capacity of dental pulp stem/progenitor cells (DPCs), but none has interrogated the impact of these cytokines on the stem cell phenotype of stem/progenitor cells. This study investigated the effects of a short-term treatment with TNF-α on the stem cell phenotype and differentiation ability of human DPCs.MethodsAn in vivo mouse model of pulp exposure was performed for analysis of expression of the mesenchymal stem cell marker CD146 in DPCs during the initial stage of inflammatory response. For in vitro studies, human DPCs were isolated and incubated with TNF-α for 2 days and passaged to eliminate TNF-α completely. Analysis of stem cell phenotype was performed by quantification of cells positive for mesenchymal stem cell markers SSEA-4 (stage-specific embryonic antigen 4) and CD146 by flow cytometry as well as by quantitative analysis of telomerase activity and mRNA levels of OCT-4 and NANOG. Cell migration, colony-forming ability, and differentiation toward odontogenesis and adipogenesis were also investigated.ResultsThe pulp exposure model revealed a strong staining for CD146 during the initial inflammatory response, at 2 days after pulp exposure. In vitro experiments demonstrated that a short-term (2-day) treatment of TNF-α increased by twofold the percentage of SSEA-4+ cells. Accordingly, STRO-1, CD146, and SSEA-4 protein levels as well as OCT-4 and NANOG mRNA levels were also significantly upregulated upon TNF-α treatment. A short-term TNF-α treatment also enhanced DPC function, including the ability to form cell colonies, to migrate, and to differentiate into odontogenic and adipogenic lineages.ConclusionsA short-term treatment with TNF-α enhanced the stem cell phenotype, migration, and differentiation ability of DPCs.

Enrichment and functional characterization of cancer stem cells from squamous cell carcinoma of head and neck by suspension culture

Initiation, growth, recurrence, and metastasis of head and neck squamous cell carcinoma (HNSCC) have been related to the cancer stem cells (CSC) that can be identified by their aldehyde-dehydrogenase-isoform-1 (ALDH-1) activity. In this study, we try to prove that suspension culture can enrich ALDH-1 high expression cells within HNSCC cell lines and the enriched cells possess cancer stem cell properties. Cells from five HNSCC cell lines were cultured in ultra-low attachment plates in serum-free Quantum 263 medium supplemented with 10 ng/ml EGF and 10 ng/ml bFGF, and ALDH-1 expression level was evaluated by ALDEFLUOR assay. ALDH-1 high expression cells were separated by FACS sorting, and their phenotypical and functional properties were characterized. Spheroids can be formed from all five HNSCC cell lines (UD-SCC1, UT-SCC22, UM-SCC11B, UT-SCC9 and UT-SCC24A) under anchorage independent culture condition. The proportion of ALDH1 high expression cells were highly increased in speroids derived cells (SDCs) compared with their monolayers (P < 0.05). The clones formed by ALDH1 high expression cells on average contained 197 (197 ± 47) cells compared with 33 (33 ± 16) cells in clones generated from ALDH1 low expression cells (P < 0.01). Single ALDH1 high expression cell could significantly better regenerate a spheroid (UT-SCC9: 17.1%, UD-SCC1:19.3%), whereas under the same conditions single ALDH1 low expression cells regenerated only in one case a spheroid (P < 0.01). SDCs from all five tested cell lines also showed a significantly increased invasion capacity (P < 0.05). We also found that the mRNA levels of Oct-4, Sox2, and Nanog were all significantly increased in the SDC. The reactive oxygen species (ROS) levels in SDCs from UD-SCC1 and UT-SCC24A were significantly increased compared with their monolayer counterpart [(26.3 ± 4.9)% vs (8.6 ± 1.7)% and (72.1 ± 6.1)% vs (23.7 ± 7.5)%, P < 0.05)]. Cancer stem cells can be enriched by suspension culture, which may be of importance in investigation of their contribution to therapy resistance, tumor recurrence and metastasis.