Mesenchymal-like Cells Research Articles

In Vitro Characterization of Adipose Stem Cells Non-Enzymatically Extracted from the Thigh and Abdomen.

Autologous fat grafting is a surgical technique in which adipose tissue is transferred from one area of the body to another, in order to reconstruct or regenerate damaged or injured tissues. Before reinjection, adipose tissue needs to be purified from blood and cellular debris to avoid inflammation and preserve the graft viability. To perform this purification, different enzymatic and mechanical methods can be used. In this study, we characterized in vitro the product of a closed automatic device based on mechanical disaggregation, named Rigenera®, focusing on two sites of adipose tissue harvesting. At first, we optimized the Rigenera® operating timing, demonstrating that 60 s of treatment allows a higher cellular yield, in terms of the cell number and growth rate. This result optimizes the mechanical disaggregation and it can increase the clinical efficiency of the final product. When comparing the extracted adipose samples from the thigh and abdomen, our results showed that the thigh provides a higher number of mesenchymal-like cells, with a faster replication rate and a higher ability to form colonies. We can conclude that by collecting adipose tissue from the thigh and treating it with the Rigenera® device for 60 s, it is possible to obtain the most efficient product.

Hsc70 is required for E-cadherin expression in epithelial-like NRK-52E cells

Heat-shock cognate protein 70 (Hsc70), a molecular chaperone, is involved in multiple cellular functions. We previously demonstrated that Hsc70 is required for TGF-β-induced Smad signaling in mesenchymal-like NRK-49F cells. In the present study, to compare the Hsc70 functions in TGF-β-related signaling between epithelial and mesenchymal cells, we examined the effect of Hsc70 downregulation on TGF-β-induced signaling in epithelial-like NRK-52E cells. TGF-β-induced Smad signaling was suppressed in cells treated with small interfering RNA (siRNA) for Hsc70. Interestingly, despite interference with TGF-β signaling, TGF-β-induced suppression of E-cadherin expression was not affected by Hsc70 knockdown. Instead, Hsc70 knockdown itself caused the suppression of E-cadherin expression at the transcription level in cells treated with Hsc70 siRNA. We also examined the effects of Hsc70 knockdown on the level of E-cadherin-gene repressors, such as Snail1, Slug, Zeb1, Zeb2, and Twist1, and found that transcription of the repressors was upregulated after 24- or 36-h treatment with Hsc70 siRNA. Collectively, these results indicate that, in addition to a supportive role in TGF-β-induced signaling, Hsc70 supports E-cadherin expression through downregulation of the E-cadherin-gene repressors in NRK-52E cells, suggesting that Hsc70 plays a functional role to maintain the epithelial cell phenotype.

The ability of miRNAs to induce mesenchymal-to-epithelial transition (MET) in cancer cells is highly dependent upon genetic background.

Understanding of the molecular basis of host cell-miRNA interactions is prerequisite to the successful application of miRNAs as potential therapeutic agents. We studied the morphological and molecular consequences of over expression of three sequence divergent miRNAs previously implicated in the mesenchymal-to-epithelial transition process (MET) in three distinct mesenchymal-like cancer cell lines. The ability of miRNAs to induce morphological changes characteristic of MET positively correlated with induced changes in the expression of genes previously implicated in the process. Variability in the responses of different mesenchymal-like cells to over expression of the same miRNAs was attributable to inherent differences in trans-regulatory profiles pre-disposing these cells to miRNA-induced MET. Collectively our results indicate that miRNA-mediated regulation of MET is a highly integrated process that is significantly modulated by the molecular background of individual cells.

Stromal Cell-Derived Factor-1 Enhances the Therapeutic Effects of Human Endometrial Regenerative Cells in a Mouse Sepsis Model.

Endometrial regenerative cells (ERCs) are mesenchymal-like stromal cells obtained from human menstrual blood, whose positive therapeutic effects have been validated in several experimental models. Stromal cell-derived factor-1 (SDF-1), the ligand for CXCR4, plays an important role in the migration of mesenchymal stromal cells. The purpose of this study was to investigate the role of the SDF-1/CXCR4 pathway in the therapeutic effects of ERCs in a mouse sepsis model. Through preexperiment and confirmation, wild-type C57BL/6 mice were intraperitoneally injected with 10 mg/kg lipopolysaccharide (LPS). The therapeutic effects of ERCs with different pretreatments were evaluated by assessing sepsis-related symptoms, detecting tissue damage and measuring levels of inflammatory and oxidative stress-related factors. The in vitro experiments demonstrated that there was a much higher CXCR4 expression on ERCs when they were cocultured with SDF-1. The ex vivo experiment results showed that SDF-1 expression significantly increased in mouse tissues. Further experiments also confirmed that, compared with the unmodified ERC treatment group, SDF-1 pretreatment significantly enhanced the therapeutic effects of ERCs on alleviating sepsis symptoms, ameliorating pathological changes, reducing Bax level, and increasing Bcl-2 and PCNA expressions in mouse liver tissues. Furthermore, it was also found that SDF-1-pretreated ERCs contributed to reducing the levels of proinflammatory cytokines (TNF-α, IL-1β) and increasing the levels of anti-inflammatory factors (IL-4, IL10) in mouse serum, liver, and lung. Moreover, SDF-1-pretreated ERCs could also significantly decrease the levels of iNOS and MDA and increase the expression of Nrf2, HO-1, and SOD in liver tissues. Taken together, these results indicate that SDF-1 pretreatment plays a key role in improving the therapeutic effects of ERCs in alleviating sepsis-related symptoms, reducing tissue damage, regulating inflammatory imbalance, and relieving oxidative stress in a mouse sepsis model, which provides more possibilities for the clinical application of ERCs in sepsis and relevant diseases.

(-)-Sativan Inhibits Tumor Development and Regulates miR-200c/PD-L1 in Triple Negative Breast Cancer Cells.

Epithelial-to-mesenchymal transition (EMT) in cancer cells could convert epithelial-like cells to mesenchymal-like cells, resulting in the increased capacity of migration and invasion of cancer cells, and is an essential step in triple negative breast cancer (TNBC) development. Recent reports exert that these EMT-activated TNBC cells are more resistant to immune attacks, with high levels of programmed death ligand1 (PD-L1). Hence, it is worthwhile to find an effective approach in inhibiting EMT-activated TNBC cells. (-)-Sativan (SA) is a naturally isolated isoflavane and could be isolated from Spatholobus suberectus, a common traditional Chinese medicine used for breast cancer treatment. It was the first time that SA exerted anti-cancer effects on breast cancer cells, according to our study. In this study, SA displayed a significant inhibitory effect on the proliferation of TNBC cells by inducing apoptosis. SA increased Bax expression, and decreased Bcl-2 protein levels. SA inhibited cell migration and invasion of MDA-MB-231 and BT-549 cells. SA could decrease N-cadherin, Snail, Vimentin, and PD-L1 expression. SA increased miR-200c expression, and decreased PD-L1 expression. Luciferase assay showed that miR-200c directly targeted PD-L1. SA promoted tumor cell susceptibility to CTL-mediated lysis. Further study confirmed that SA could inhibit PD-L1 expression and EMT by up-regulating miR-200c. In vivo results displayed that SA could also inhibit tumor volumes and weights. These findings indicate that SA exerts an inhibitory effect on TNBC cell proliferation, migration, invasion, and tumor gtrowth, and partly provide evidence for the anti-breast cancer effect of Spatholobus suberectus Dunn in TNBC therapy.

Chemoresistant ovarian cancer enhances its migration abilities by increasing store-operated Ca2+ entry-mediated turnover of focal adhesions

BackgroundAmong gynecological cancers, ovarian carcinoma has the highest mortality rate, and chemoresistance is highly prevalent in this cancer. Therefore, novel strategies are required to improve its poor prognosis. Formation and disassembly of focal adhesions are regulated dynamically during cell migration, which plays an essential role in cancer metastasis. Metastasis is intricately linked with resistance to chemotherapy, but the molecular basis for this link is unknown.MethodsTranswell migration and wound healing migration assays were used to analyze the migration ability of ovarian cancer cells. Real-time recordings by total internal reflection fluorescence microscope (TIRFM) were performed to assess the turnover of focal adhesions with fluorescence protein-tagged focal adhesion molecules. SOCE inhibitors were used to verify the effects of SOCE on focal adhesion dynamics, cell migration, and chemoresistance in chemoresistant cells.ResultsWe found that mesenchymal-like chemoresistant IGROV1 ovarian cancer cells have higher migration properties because of their rapid regulation of focal adhesion dynamics through FAK, paxillin, vinculin, and talin. Focal adhesions in chemoresistant cells, they were smaller and exhibited strong adhesive force, which caused the cells to migrate rapidly. Store-operated Ca2+ entry (SOCE) regulates focal adhesion turnover, and cell polarization and migration. Herein, we compared SOCE upregulation in chemoresistant ovarian cancer cells to its parental cells. SOCE inhibitors attenuated the assembly and disassembly of focal adhesions significantly. Results of wound healing and transwell assays revealed that SOCE inhibitors decreased chemoresistant cell migration. Additionally, SOCE inhibitors combined with chemotherapeutic drugs could reverse ovarian cancer drug resistance.ConclusionOur findings describe the role of SOCE in chemoresistance-mediated focal adhesion turnover, cell migration, and viability. Consequently, SOCE might be a promising therapeutic target in epithelial ovarian cancer.Graphical abstract

Clinical Evolution of Epithelial-Mesenchymal Transition in Human Carcinomas.

The significance of the phenotypic plasticity afforded by epithelial-mesenchymal transition (EMT) for cancer progression and drug resistance remains to be fully elucidated in the clinic. We evaluated epithelial-mesenchymal phenotypic characteristics across a range of tumor histologies using a validated, high-resolution digital microscopic immunofluorescence assay (IFA) that incorporates β-catenin detection and cellular morphology to delineate carcinoma cells from stromal fibroblasts and that quantitates the individual and colocalized expression of the epithelial marker E-cadherin (E) and the mesenchymal marker vimentin (V) at subcellular resolution ("EMT-IFA"). We report the discovery of β-catenin+ cancer cells that coexpress E-cadherin and vimentin in core-needle biopsies from patients with various advanced metastatic carcinomas, wherein these cells are transitioning between strongly epithelial and strongly mesenchymal-like phenotypes. Treatment of carcinoma models with anticancer drugs that differ in their mechanism of action (the tyrosine kinase inhibitor pazopanib in MKN45 gastric carcinoma xenografts and the combination of tubulin-targeting agent paclitaxel with the BCR-ABL inhibitor nilotinib in MDA-MB-468 breast cancer xenografts) caused changes in the tumor epithelial-mesenchymal character. Moreover, the appearance of partial EMT or mesenchymal-like carcinoma cells in MDA-MB-468 tumors treated with the paclitaxel-nilotinib combination resulted in upregulation of cancer stem cell (CSC) markers and susceptibility to FAK inhibitor. A metastatic prostate cancer patient treated with the PARP inhibitor talazoparib exhibited similar CSC marker upregulation. Therefore, the phenotypic plasticity conferred on carcinoma cells by EMT allows for rapid adaptation to cytotoxic or molecularly targeted therapy and could create a form of acquired drug resistance that is transient in nature. SIGNIFICANCE: Despite the role of EMT in metastasis and drug resistance, no standardized assessment of EMT phenotypic heterogeneity in human carcinomas exists; the EMT-IFA allows for clinical monitoring of tumor adaptation to therapy.

Mesenchymal Stromal Cells from Fetal and Maternal Placenta Possess Key Similarities and Differences: Potential Implications for Their Applications in Regenerative Medicine.

Placenta-derived mesenchymal stromal cells (MSC) have attracted more attention for their immune modulatory properties and poor immunogenicity, which makes them suitable for allogeneic transplantation. Although MSC isolated from different areas of the placenta share several features, they also present significant biological differences, which might point to distinct clinical applications. Hence, we compared cells from full term placenta distinguishing them on the basis of their origin, either maternal or fetal. We used cells developed by Pluristem LTD: PLacenta expanded mesenchymal-like adherent stromal cells (PLX), maternal-derived cells (PLX-PAD), fetal-derived cells (PLX-R18), and amniotic membrane-derived MSC (hAMSC). We compared immune modulatory properties evaluating effects on T-lymphocyte proliferation, expression of cytotoxicity markers, T-helper and T-regulatory cell polarization, and monocyte differentiation toward antigen presenting cells (APC). Furthermore, we investigated cell immunogenicity. We show that MSCs and MSC-like cells from both fetal and maternal sources present immune modulatory properties versus lymphoid (T cells) and myeloid (APC) cells, whereby fetal-derived cells (PLX-R18 and hAMSC) have a stronger capacity to modulate immune cell proliferation and differentiation. Our results emphasize the importance of understanding the cell origin and characteristics in order to obtain a desired result, such as modulation of the inflammatory response that is critical in fostering regenerative processes.

Cytoplasm-localized SIRT1 downregulation attenuates apoptosis and cell cycle arrest in cisplatin-resistant lung cancer A549 cells.

Objective: We propose that sirtuin (SIRT) may induce a pro-apoptotic effect by deacetylating transcription factors in A549 cells: depletion of sirtuin-1 (SIRT1) induced cell cycle arrest in cisplatin-resistant A549 (A549/CADD) cells.Methods: Protein and mRNA levels of SIRT1 were investigated using western blot and RT-PCR. In A549 and A549/CADD cells, the cytotoxicity of cisplatin administration was evaluated by MTT assay, proliferation was measured by ECIS, and the cell cycle distribution was analyzed using FACS. Cells were transfected with pcDNA3.1-Myc-SIRT1 or pcDNA3.1-Myc-Control vectors to analyze the impact of SIRT-1 on cisplatin induced drug resistance. SIRT1 localization was studied using immunofluorescence analysis. In addition, immunoprecipitation and 20S proteasome activity assay were performed to examine the relationship of SIRT1 with the proteasome complex.Results: A549/CADD cells exhibited a mesenchymal-like cell characteristic. SIRT1 expression was markedly decreased in A549/CADD cells. We observed that cisplatin regulates p53 stability through the depletion of ubiquitination following SIRT1 downregulation. Furthermore, cisplatin treatment increased proteasomal activity and significantly decreased cytoplasmic SIRT1 protein levels in A549/CADD cells.Conclusion: In this study, we found SIRT1 to be depleted in A549/CADD cells and also determined the underlying resistance mechanism which may act as novel therapeutic targets in overcoming drug resistance.

CBMT-20. SINGLE-CELL TRANSCRIPTOMICS RESOLVES CELLULAR HETEROGENEITY AND ONCOGENIC NETWORKS DURING MALIGNANT TRANSFORMATION OF PERIPHERAL NERVE SHEATH TUMORS

Abstract Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive Schwann cell (SC)-derived sarcomas with strong metastatic proclivity and resistance to radiation and chemotherapy. Molecular events driving SC-to-MPNST transformation are incompletely understood. MPNST are heterogeneous tumors with a distinct microenvironment that contributes to the establishment of a tumor niche. Cancer behaviors including initiation, progression, metastasis and relapse cannot be fully defined by genetic mutations alone, but are critically dependent on intercellular communication between tumor cells and the microenvironment. However, currently, a comprehensive understanding of tumor cell lineage evolution, heterogeneity and cell-cell communication network in MPNST is lacking. A better understanding of cellular heterogeneity and tumor-initiating cells during tumorigenesis at a single-cell level will facilitate identifying molecular and cellular determinants underlying malignant transformation in MPNST. We have established a murine model of aggressive peripheral nerve malignancy with HIPPO-TAZ/YAP activation (Lats1/2-def mice), which provides a unique opportunity for dissecting mechanisms of SC malignant transformation. To identify potential PNST-driven progenitor populations, we compare single-cell transcriptome profiles of Lats1/2-def sciatic nerve tumors during pre-neoplastic and advanced stages. Our data reveal that early sciatic nerve tumors contain primarily mature SCs, whereas full-blown tumors harbor neoplastic SCs composed of different subsets: fast-proliferating, mesenchymal-like and neural crest stem cell-like cells, indicative of a developmental trajectory from differentiated SCs to tumor-like SCs with distinct molecular and transcriptional signatures. Interestingly, transformed SCs exhibit inflammation gene signature, which may suggest cell-autonomous inflammation-driven reprogramming that drives tumorigenesis. To characterize cellular heterogeneity in MPNST-like tumors, we further identify cell-cell communication networks between SC-derived tumor cells and cancer-associated stromal cells within the tumor microenvironment. In summary, our studies using single-cell transcriptomics in clinically relevant mouse models of PNST reveal tumor cellular heterogeneity and the microenvironment niche for driving SC tumorigenesis. It will provide principles for identifying potential targets or treatment strategies to cure MPNST.

Addiction of mesenchymal phenotypes on the FGF/FGFR axis in oral squamous cell carcinoma cells.

The epithelial–mesenchymal transition (EMT) is a crucial morphological event that occurs during epithelial tumor progression. ZEB1/2 are EMT transcription factors that are positively correlated with EMT phenotypes and breast cancer aggressiveness. ZEB1/2 regulate the alternative splicing and hence isoform switching of fibroblast growth factor receptors (FGFRs) by repressing the epithelial splicing regulatory proteins, ESRP1 and ESRP2. Here, we show that the mesenchymal-like phenotypes of oral squamous cell carcinoma (OSCC) cells are dependent on autocrine FGF–FGFR signaling. Mesenchymal-like OSCC cells express low levels of ESRP1/2 and high levels of ZEB1/2, resulting in constitutive expression of the IIIc-isoform of FGFR, FGFR(IIIc). By contrast, epithelial-like OSCC cells showed opposite expression profiles for these proteins and constitutive expression of the IIIb-isoform of FGFR2, FGFR2(IIIb). Importantly, ERK1/2 was constitutively phosphorylated through FGFR1(IIIc), which was activated by factors secreted autonomously by mesenchymal-like OSCC cells and involved in sustained high-level expression of ZEB1. Antagonizing FGFR1 with either inhibitors or siRNAs considerably repressed ZEB1 expression and restored epithelial-like traits. Therefore, autocrine FGF–FGFR(IIIc) signaling appears to be responsible for sustaining ZEB1/2 at high levels and the EMT phenotype in OSCC cells.

Cellular Invasion and Matrix Degradation, a Different Type of Matrix-Degrading Cells in the Cartilage of Catfish (Clarias gariepinus) and Japanese Quail Embryos (Coturnix coturnix japonica).

We previously studied the phenomena of the mesenchymal cell-dependent mode of cartilage growth in quail and catfish. Thus, we selected the two cartilage models in which mesenchymal cells participate in their growth. In such models, cartilage degradation occurred to facilitate cellular invasion. The studies do not explain the nature of the cartilage degrading cells. The current study aims to explore the nature of the cartilage-degrading cells using transmission electron microscopy (TEM) and immunohistochemistry. Samples of cartilage have been isolated from the air-breathing organ of catfish and the cartilage of the prospective occipital bone of quail embryos. Samples have been processed for TEM and immunohistochemistry. We found that two different cell types are involved in cartilage degradation; the macrophage in the cartilage of catfish and mesenchymal cells in the cartilage of the quail. Areas of cellular invasion in both catfish cartilage and quail embryo cartilage had an immunological affinity for MMP-9. In catfish, cartilage-degrading cells had identical morphological features of macrophages, whereas in quail embryos, cartilage-degrading cells were mesenchymal-like cells which had cell processes rich in vesicles and expressed CD117. Further study should consider the role of macrophage and mesenchymal cells during cartilage degradation. This could be valuable to be applied to remove the defective cartilage matrix formed in osteoarthritic patients to improve cartilage repair strategies.

1254 Sarcomatoid Carcinoma of the Head of the Pancreas: A Rare Case

INTRODUCTION: To the best of our knowledge, a total of 23 cases of sarcomatoid or carcinosarcoma of the pancreas have been reported. 1 Sarcomatoid carcinoma of the pancreas (SCP) is a rare and aggressive malignant neoplasm with evidence of epithelial and mesenchymal features. Confirmation of this disease currently relies on detailed pathologic examinations. SCP is comparatively more aggressive with a poorer prognosis than that of conventional pancreatic carcinomas. Therefore, SCP can be a challenge both diagnostically and therapeutically for clinicians and surgeons alike. The presenting case illustrates and highlights potential indications that can be used to diagnose and treat SCP much earlier than conventional medicine currently allows. CASE DESCRIPTION/METHODS: We present a case of SCP in an 84-year-old male patient. He had experienced jaundice and epigastric abdominal pain for 4 weeks. An ultrasound revealed a hypoechoic mass at the pancreatic head which prompted referral to our gastroenterology group. Physical examination revealed scleral icterus, cutaneous jaundice, and left hip and lower back pain. Laboratory tests yielded the following results: total bilirubin of 13.4 U/L, AST/ALT of 171 U/L and 240 U/L respectively, and an alkaline phosphatase of 714 U/L. Imaging examinations were performed including MRCP, EUS, and CT noting a mass in the pancreatic head. Due to the aggressiveness of this patient's tumor and despite medical efforts, the patient succumbed to his illness shortly after the official diagnosis was discovered and before any therapeutic measures could have been initiated. DISCUSSION: Our final diagnosis of SCP was made via pathologic examination as high-grade malignant sarcomatoid neoplasm with spindled areas, ample mitosis, and necrosis. IHC analysis showed positive expression for cytokeratin, vimentin, CD56, and a Ki-67 with a proliferative rate of greater than 90%. Other immunomarkers for melanoma, smooth muscle, and lymphoma were negative. These findings are indicative of sarcomatoid morphology and phenotype. Although definitions of SCP vary, it is believed that SCP features spindle cells and possesses mesenchymal-like and epithelial-like appearances. 1 Due to the histological report of spindle cell patterns and the co-presence of mesenchymal-like and epithelial-like cells illustrated using immunostaining techniques, our case is most consistent with SCP.

Phenotypic, structural, and ultrastructural analysis of triple-negative breast cancer cell lines and breast cancer stem cell subpopulation.

Triple negative breast cancer (TNBC) is a highly heterogeneous disease, which influences the therapeutic response and makes difficult the discovery of effective targets. This heterogeneity is attributed to the presence of breast cancer stem cells (BCSCs), which determines resistance to chemotherapy and subsequently disease recurrence and metastasis. In this context, this work aimed to evaluate the morphological and phenotypic cellular heterogeneity of two TNBC cell lines cultured in monolayer and tumorsphere (TS) models by fluorescence and electron microscopy and flow cytometry. The BT-549 and Hs 578T analyses demonstrated large phenotypic and morphological heterogeneity between these cell lines, as well as between the cell subpopulations that compose them. BT-549 and Hs 578T are heterogeneous considering the cell surface marker CD44 and CD24 expression, characterizing BCSC mesenchymal-like cells (CD44+/CD24-), epithelial cells (CD44-/CD24+), hybrid cells with mesenchymal and epithelial features (CD44+/CD24+), and CD44-/CD24- cells. BCSC epithelial-like cells (ALDH+) were found in BT-549, BT-549 TS, and Hs 578T TS; however, only BT-549 TS showed a high ALDH activity. Ultrastructural characterization showed the heterogeneity within and among BT-549 and Hs 578T in monolayer and TS models being formed by more than one cellular type. Further, the mesenchymal characteristic of these cells is demonstrated by E-cadherin absence and filopodia. It is well known that tumor cell heterogeneity can influence survival, therapy responses, and the rate of tumor growth. Thus, molecular understanding of this heterogeneity is essential for the identification of potential therapeutic options and vulnerabilities of oncological patients.

Liquid biopsy-based single-cell metabolic phenotyping of lung cancer patients for informative diagnostics

Accurate prediction of chemo- or targeted therapy responses for patients with similar driver oncogenes through a simple and least-invasive assay represents an unmet need in the clinical diagnosis of non-small cell lung cancer. Using a single-cell on-chip metabolic cytometry and fluorescent metabolic probes, we show metabolic phenotyping on the rare disseminated tumor cells in pleural effusions across a panel of 32 lung adenocarcinoma patients. Our results reveal extensive metabolic heterogeneity of tumor cells that differentially engage in glycolysis and mitochondrial oxidation. The cell number ratio of the two metabolic phenotypes is found to be predictive for patient therapy response, physiological performance, and survival. Transcriptome analysis reveals that the glycolytic phenotype is associated with mesenchymal-like cell state with elevated expression of the resistant-leading receptor tyrosine kinase AXL and immune checkpoint ligands. Drug targeting AXL induces a significant cell killing in the glycolytic cells without affecting the cells with active mitochondrial oxidation.

SDF-1/CXCR4 axis enhances the immunomodulation of human endometrial regenerative cells in alleviating experimental colitis

Endometrial regenerative cells (ERCs) are a new type of mesenchymal-like stromal cells, and their therapeutic potential has been tested in a variety of disease models. SDF-1/CXCR4 axis plays a chemotaxis role in stem/stromal cell migration. The aim of the present study was to investigate the role of SDF-1/CXCR4 axis in the immunomodulation of ERCs on the experimental colitis. The immunomodulation of ERCs in the presence or absence of pretreatment of SDF-1 or AMD3100 was examined in both in vitro cell culture system and dextran sulphate sodium-induced colitis in mice. The results showed that SDF-1 increased the expression of CXCR4 on the surface of ERCs. As compared with normal ERCs, the SDF-1-treated, CXCR4 high-expressing ERCs more significantly suppressed dendritic cell population as well as stimulated both type 2 macrophages and regulatory T cells in vitro and in vivo. Meanwhile, SDF-1-pretreated ERCs increased the generation of anti-inflammatory factors (e.g., IL-4, IL-10) and decreased the pro-inflammatory factors (e.g., IL-6, TNF-α). In addition, SDF-1-pretreated CM-Dil-labeled ERCs were found to engraft to injured colon. Our results may suggest that an SDF-1-induced high level of CXCR4 expression enhances the immunomodulation of ERCs in alleviating experimental colitis in mice.

Use of Human Placenta-Derived Cells in a Preclinical Model of Tendon Injury.

Emerging data suggest that human cells derived from extraembryonic tissues may have favorable musculoskeletal repair properties. The purpose of this study was to determine whether the injection of human placenta-derived mesenchymal-like stromal cells, termed placental expanded cells (PLX-PAD), would improve tendon healing in a preclinical model of tendinopathy. Sixty male Sprague-Dawley rats underwent bilateral patellar tendon injection with either saline solution (control) or PLX-PAD cells (2 × 10 cells/100 µL) 6 days after collagenase injection to induce tendon degeneration. Animals were killed at specific time points for biomechanical, histological, and gene expression analyses of the healing patellar tendons. Biomechanical testing 2 weeks after the collagenase injury demonstrated better biomechanical properties in the tendons treated with PLX-PAD cells. The load to failure of the PLX-PAD-treated tendons was higher than that of the saline-solution-treated controls at 2 weeks (77.01 ± 10.51 versus 58.87 ± 11.97 N, p = 0.01). There was no significant difference between the 2 groups at 4 weeks. There were no differences in stiffness at either time point. Semiquantitative histological analysis demonstrated no significant differences in collagen organization or cellularity between the PLX-PAD and saline-solution-treated tendons. Gene expression analysis demonstrated higher levels of interleukin-1β (IL-1β) and IL-6 early in the healing process in the PLX-PAD-treated tendons. Human placenta-derived cell therapy induced an early inflammatory response and a transient beneficial effect on tendon failure load in a model of collagenase-induced tendon degeneration. Human extraembryonic tissues, such as the placenta, are an emerging source of cells for musculoskeletal repair and may hold promise as a point-of-care cell therapy for tendon injuries.

The secretome of adipose-derived mesenchymal stem cells attenuates epithelial–mesenchymal transition in human corneal epithelium

IntroductionEpithelial–mesenchymal transition (EMT) induces the loss of cell–cell interactions in polarized epithelial cells and converts these cells to invasive mesenchymal-like cells. It is also involved in tissue fibrosis including that occurring in some ocular surface diseases such as pterygium and in subepithelial corneal fibrosis in limbal stem cell deficiency. Here, we examined the effects of the secretome of human adipose-derived mesenchymal stem cells (AdMSCs) on EMT in human corneal epithelial cells (CECs).MethodsEMT was induced with transforming growth factor-β (TGF-β) in primary human CECs isolated from the human corneal limbus. The effects of the AdMSC secretome on EMT in these cells or stratified CEC sheets were analyzed by co-cultivation experiments with the addition of AdMSC conditioned-medium. The expression of EMT-related genes and proteins in CECs was analyzed. The superstructure of CECs was observed by scanning electron microscopy. Furthermore, the barrier function of CEC sheets was analyzed by measuring transepithelial electrical resistance (TER).ResultsThe AdMSC secretome was found to suppress EMT-related gene expression and attenuate TGF-β-induced corneal epithelial dysfunction including the dissociation of cell–cell interactions and decreases in TER in constructed CEC sheets.ConclusionsThe secretome of AdMSCs can inhibit TGF-β-induced EMT in CECs. These findings suggest that this could be a useful source for the treatment for EMT-related ocular surface diseases.

Abstract 759: microRNA 26a-5p inhibited stemness and enhanced the chemosensitivity of non-small cell lung cancer

Abstract Only a subpopulation of cells which have the ability to regulate self-renewal and differentiation of cancer cells, are able to tumorigenic capacity. This subpopulation of cells is called cancer stem cells (CSC). Cancer stem cells are also identified in lung cancer and exhibits resistance to chemotherapy, radiotherapy and targeted therapy. Therefore, the technology to control CSCs is a good strategy to overcome resistance to cancer therapy. Epithelial-mesenchymal transition (EMT) has been linked with the generation of cancer stem cells (CSCs). Recent evidence proposes that EMT-related transcriptomic alterations correlate with the acquisition of CSC phenotype. In previous study, we investigated the miRNA profiles of mesenchymal-like lung cancer cell lines to evaluate the relationship beween EMT and miRNA in non-small cell lung cancer (NSCLC). miR-26a-5p is down-regulated in mesenchymal like lung cancer cell lines. These findings suggested miR-26a-5p may be involved in cancer stemness of lung cancer cells. To test that miR-26a-5p has a role in stemness of lung cancer, we performed colony formation assay, sphere formation assay and fluorescence activated cell sorting. RNA polymerase III subunit G (POLR3G) was selected as a candidate target of miR-26a-5p related to cancer stemness. To verify that miR-26a-5p regulates POLR3G, we performed qRT-PCR, western blot and luciferase assays. Cell proliferation assay was performed to evaluate miR-26a-5p’s role of chemosensitizer. The overexpression of miR-26a-5p induced a marked reduction of the colony formation and sphere formation in non-small lung cancer cell lines. Overexpression of miR-26a-5p lead to reduction of CD133+ cells. Co-treatment with miR-26-5p and Paclitaxel treatment showed a significant reduction of growth. miR-26a-5p regulated the expression of POLR3G at the mRNA and protein levels. These data demonstrate for the first time that miR-26a-5p suppresses lung cancer stemness by repressing POLR3G expression. This provides new insight into a potential approach for the treatment of lung cancer by regulating cancer stemness. Citation Format: Jiwoong Son, Sun Jung Kwon, In Beom Jeong, Ji Hye Kim. microRNA 26a-5p inhibited stemness and enhanced the chemosensitivity of non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 759.

Abstract 2897: Dynamic transdifferentiation programs in small cell lung carcinoma

Abstract Tumors must also have the ability to rapidly adjust to a mutable environment during the lifespan of the cell. This form of phenotypic plasticity is typified by biological programs regulated by a host of transcription factors in a well-coordinated “switch” that is initiated by both cell autonomous and microenvironmental cues. We sought to study these dynamics in small cell lung carcinoma (SCLC). First, we used k-means clustering to identify discrete transcriptional programs that are represented across SCLC using gene expression values from 53 and 71 SCLC cell lines and primary tumors, respectively. To investigate these programs further, we used our inventory of 67 patient-derived xenografts (PDX) to establish an ex vivo cell culture system that reconstitutes with high fidelity the gene expression values observed in the PDXs and the primary tumors from which these cells were derived. Our data demonstrates that gene expression groupings or clusters across samples mark distinct SCLC transcriptional states, representing intertumoral variation. However, in an intriguing demonstration of intratumoral heterogeneity, the very same groupings define morphologically and phenotypically distinct subpopulations within individual samples. Subpopulations were represented by suspending aggregates of very small cells (neuroendocrine or NEn), pre-suspension aggregates that are nested above mesenchymal-like cells and appear to give rise to the suspending aggregates (proneural or PN), pleomorphic cells growing as a monolayer composed of larger cells with visible cytoplasm and spindle-like membrane extensions (mesenchymal or MS), and semi-adherent cells that are physically positioned over the latter (neuroepithelial or NEp). WES demonstrated high genetic fidelity across all subpopulations, indicating that the significant morphologic and phenotypic differences were non-genetic. RNAseq and gene ontology was applied to differentially expressed genes to inform classifications. Using network analyses, we identified transcription factors (TFs) that function as central nodes in the gene expression networks of each population. Namely, we show that ASCL1 marks a rapidly proliferating neuroendocrine population (NEn), NEUROD1 marks a primitive neural population (PN) and YAP1 marks a slow-growing mesenchymal population (MS). We also developed a promoter-reporter fluorescent protein system that positions distinctly colored fluorescent proteins under the regulatory control of the promoters of the three TFs. We show that a Markov process models the transition probability of states. Taken together, our results show that human SCLC is comprised of distinct tumor subpopulations characterized by significant, non-genetic plasticity. We posit that understanding of the SCLC intratumoral ecosystem can create new opportunities to evolutionarily steer this tumor toward improved therapeutic results. Note: This abstract was not presented at the meeting. Citation Format: Priyanka Gopal, Kevin Rogacki, Craig D. Peacock, Mohamed E. Abazeed. Dynamic transdifferentiation programs in small cell lung carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2897.