Stemness Properties Research Articles

A Preliminary Determination of Mechanical and Suspension Properties of Waste Mulch Film and Cotton Stalk

In order to provide basic data and a theoretical basis for waste mulch film crushing and separation equipment, the mechanical and suspension properties of waste mulch film and cotton stalk were determined in this study. In the mechanical properties test, the tensile properties of waste mulch film and the shear properties of different parts of cotton stalk were investigated. In the suspension properties test, the suspension properties of different qualities of waste mulch film and different parts of cotton stalk were investigated. The results showed that the average maximum tensile forces and fracture displacements of the waste mulch film were 1.70 N (horizontal), 0.80 N (vertical) and 254.75 mm (horizontal), 145.22 mm (vertical). The shear properties of the cotton stem after wrapping the mulch film were greatly improved; the maximum shearing force was 186.89% higher than that of the unwrapped specimens. When the total suspension velocity was from 3.09 to 4.07 m/s, separation of mulch film and cotton stalk could be achieved by wind.

Micropattern‐Based Stem Cell Gym: Mechanical Memory Enhanced Stemness Maintenance of Human Dental Pulp Stem Cells and Nerve Regeneration

AbstractDental pulp stem cells (DPSCs) which are derived from the neural crest are promising tools in stem cell therapy in the clinic. However, they tend to lose their multi‐lineage potency spontaneously during long‐term expansion in vitro. A micropattern‐based system is developed to train DPSCs with 1024 µm2 and aspect ratios of 1:2 and 1:4, which enhances their stemness and differentiation potential. This mechanical memory induced by micropattern would also rescue the pluripotency of long‐term expansion DPSCs. Micropatterns remodel the cytoskeleton and nuclear morphology, soften the cells, and induce the mitochondria into an immature state. Micropattern also activates extracellular related kinase, signal transducer, and activator of transcription 3, and inhibits Yes‐associated protein nuclear localization to enhance the stemness of DPSCs. In vivo implantation proves that DPSCs mechanically trained by micropattern could promote nerve regeneration in rats with peripheral nerve injury. A micropattern‐based approach is provided as a stem cell gym that absents exogenous growth factors to enhance the stemness and regenerative properties of DPSCs. It may shed light on future stem cell therapy.

SOX9 knockout decreases stemness properties in colorectal cancer cells.

Colorectal cancer (CRC) is a leading cause of death worldwide. SRY-box transcription factor 9 (SOX9) participates in organogenesis and cell differentiation in normal tissues but has been involved in carcinogenesis development. Cancer stem cells (CSCs) are a small population of cells present in solid tumors that contribute to increased tumor heterogeneity, metastasis, chemoresistance, and relapse. CSCs have properties such as self-renewal and differentiation, which can be modulated by many factors. Currently, the role of SOX9 in the maintenance of the stem phenotype has not been well elucidated, thus, in this work we evaluated the effect of the absence of SOX9 in the stem phenotype of CRC cells. We knockout (KO) SOX9 in the undifferentiated CRC cell line HCT116 and evaluated their stemness properties using sphere formation assay, differentiation assay, and immunophenotyping. SOX9-KO affected the epithelial morphology of HCT116 cells and stemness characteristics such as its pluripotency signature with the increase of SOX2 as a compensatory mechanism to induce SOX9 expression, the increase of KLF4 as a differentiation feature, as well as the inhibition of the stem cell markers CD44 and CD73. In addition, SOX9-KO cells gain the epithelial-mesenchymal transition (EMT) phenotype with a significant upregulation of CDH2. Furthermore, our results showed a remarkable effect on first- and second-sphere formation, being SOX9-KO cells less capable of forming high-size-resistant spheres. Nevertheless, CSCs surface markers were not affected during the differentiation assay. Collectively, our findings supply evidence that SOX9 promotes the maintenance of stemness properties in CRC-CSCs.

Hyaluronic acid-graphene oxide quantum dots nanoconjugate as dual purpose drug delivery and therapeutic agent in meta-inflammation

Type 2 diabetes mellitus (T2DM) predominantly considered a metabolic disease is now being considered an inflammatory disease as well due to the involvement of meta-inflammation. Obesity-induced adipose tissue inflammation (ATI) is one of the earliest phenomena in the case of meta-inflammation, leading to the advent of insulin resistance (IR) and T2DM. The key events of ATI are orchestrated by macrophages, which aggravate the inflammatory state in the tissue upon activation, ultimately leading to systemic chronic low-grade inflammation and Non-Alcoholic Steatohepatitis (NASH) through the involvement of proinflammatory cytokines. The CD44 receptor on macrophages is overexpressed in ATI, NASH, and IR. Therefore, we developed a CD44 targeted Hyaluronic Acid functionalized Graphene Oxide Quantum Dots (GOQD-HA) nanocomposite for tissue-specific delivery of metformin. Metformin-loaded GOQD-HA (GOQD-HA-Met) successfully downregulated the expression of proinflammatory cytokines and restored antioxidant status at lower doses than free metformin in both palmitic acid-induced RAW264.7 cells and diet induced obese mice. Our study revealed that the GOQD-HA nanocarrier enhanced the efficacy of Metformin primarily by acting as a therapeutic agent apart from being a drug delivery platform. The therapeutic properties of GOQD-HA stem from both HA and GOQD having anti-inflammatory and antioxidant properties respectively. This study unravels the function of GOQD-HA as a targeted drug delivery option for metformin in meta-inflammation where the nanocarrier itself acts as a therapeutic agent.Graphical

Mesenchymal Stem Cell-Derived Extracellular Vesicles Increase Human MCF7 Breast Cancer Cell Proliferation associated with OCT4 Expression and ALDH Activity.

The aim of this study was to investigate the effect of mesenchymal stem cells-derived extracellular vesicles (MSC-EVs) on the human MCF7 breast cancer cell proliferation that have been considered to contain limited CSC population and its association with the expression of OCT4 and ALDH1 stemness markers. EVs were successfully isolated from the conditioned medium of umbilical cord MSCs using size exclusion chromatography. The isolated EV fraction was verified under a transmission electron microscope (TEM). Five and ten percent (v/v) concentration of MSC-EVs were then co-cultured with MCF7 cells. To investigate MSC-EV uptake by MCF7 cells, we performed confocal microscopy analysis. Subsequently, the proliferation of co-cultured MCF7 cells was determined using trypan blue exclusion assay, while their mRNA and protein expression of OCT4 as well as ALDH activity as the marker of stemness properties were analyzed using quantitative reverse transcription polymerase chain reaction, Western Blot, and Aldefluor™ assays, respectively. MSC-EVs were detected as round-shaped, ~100 nm sized particles under TEM. We also demonstrate that MSC-EVs can be internalized by MCF7 cells. Notably, MSC-EVs of 5% concentration increased OCT4 mRNA expression and ALDH1 activity in MCF7 cells. At 10% concentration, MSC-EVs reduced the OCT4 expression and ALDH1 activity. MSC-derived EVs modulate the stemness of MCF7 cells, either OCT4 expression or ALDH1 activity, in a concentration dependent manner along with the increase of cell proliferation.

Boswellic acid formulations are not suitable for treatment of pediatric high-grade glioma due to tumor promoting potential

Background and aimPediatric high-grade gliomas (pedHGG) comprise a very poor prognosis. Thus, parents of affected children are increasingly resorting to complementary and alternative medicine (CAM), among those Boswellia extracts. However, nothing is known about the therapeutic effectiveness of their active substances, Boswellic acids (BA) in pedHGG. Thus, we aimed to investigate if the three main Boswellic acids (BA) present in Boswellia plants, alpha-boswellic acid (α-BA), beta-boswellic acid (β-BA) and 3-acetyl-11-keto-beta-boswellic acid (AKBA) hold any promising potential for treatment of affected pedHGG patients. Experimental procedureHistone 3 (H3)-wildtype and H3.3K27M-mutant pedHGG cell lines were treated with BA, either alone or in combination with radio-chemotherapy with temozolomide. Cell viability, stemness properties, apoptosis, in ovo tumor growth and the transcriptome was investigated upon BA treatment. Results and conclusionInterestingly, α-BA and β-BA treatment promoted certain tumor properties in both pedHGG cells. AKBA treatment reduced cell viability and colony growth accompanied by induction of slight anti-inflammatory effects especially in H3.3K27M-mutant pedHGG cells. However, no effects on apoptosis and in ovo tumor growth were found. In conclusion, besides positive anti-tumor effects of AKBA, tumor promoting effects were observed upon treatment with α-BA and β-BA. Thus, only pure AKBA formulations may be used to exploit any potential positive effects in pedHGG patients. In conclusion, the use of commercially available supplements with a mixture of different BA cannot be recommended due to detrimental effects of certain BA whereas pure AKBA formulations might hold some potential as therapeutic supplement for treatment of pedHGG patients.

MiR‑122/SENP1 axis confers stemness and chemoresistance to liver cancer through Wnt/β‑catenin signaling.

The property of inherent stemness of tumor cells coupled with the development of chemoresistance results in a poor prognosis for patients with liver cancer. Therefore, the present study focused on microRNA (miR)-122, a potential tumor suppressor, the expression of which has been previously shown to be significantly decreased and negatively associated with cancer cell stemness in liver cancer. The present study aimed to identify the molecular targets of miR-122 whilst uncovering the mechanism underlying chemoresistance and stemness of HepG2 cells in liver cancer. Bioinformatics online tools, such as ENCORI, coupled with dual-luciferase reporter assays in HepG2 cells, were used to identify and validate small ubiquitin-like modifier (SUMO) specific peptidase 1 (SENP1) as a potential target of miR-122 in liver cancer. The liver cancer stem cell population was determined using sphere formation assays and flow cytometry, whilst stem cell markers (Oct3/4, Nanog, B lymphoma Mo-MLV insertion region 1 homolog and Notch1) were detected by reverse transcription-quantitative PCR. Chemoresistance, cell proliferation and migratory ability of HepG2 cells were monitored using Cell Counting Kit-8, colony formation and Transwell assays, respectively. The overexpression of miR-122 by mimic transfection led to a significant decrease in the number spheres, downregulation of stem cell marker expression, the number of CD24+ cells, drug-resistance protein levels (P-glycoprotein and multidrug resistance protein), impaired chemoresistance, proliferation and migration of HepG2 cells. The transfection of SENP1 overexpression vector resulted in contrasting functions to miR-122 mimics, by partially reversing the effects induced by miR-122 mimic transfection in HepG2 cells. Wnt/β-catenin signaling has been proven to be involved in cancer stemness and malignant behavior. Western blotting analysis in HepG2 cells showed that the expression levels of both Wnt1 and β-catenin were significantly reduced after overexpressing miR-122, but increased after overexpressing SENP1. Co-transfection with the SENP1 overexpression vector reversed the suppression induced by the miR-122 mimics on Wnt1 and β-catenin expression. Co-immunoprecipitation, SUMOylation and half-life assays showed SENP1 interacted with β-catenin and decreased the SUMOylation of β-catenin, thereby enhancing its stability. Finally, tumor xenograft analyses revealed that HepG2 cells transfected with Agomir-122 exerted significantly lower tumor initiation frequency and growth rate, and a superior response to DOX in vivo, compared with those transfected with Agomir NC. Taken together, data from the present study miR-122/SENP1 axis can regulate β-catenin stability through de-SUMOylation, thereby promoting stemness and chemoresistance in liver cancer.

Human platelet lysate stimulates neurotrophic properties of human adipose-derived stem cells better than Schwann cell-like cells

BackgroundTrauma-associated peripheral nerve injury is a widespread clinical problem causing sensory and motor disabilities. Schwann cells (SCs) contribute to nerve regeneration, mainly by secreting nerve growth factor (NGF) and brain-derived neurotrophic factor. In the last years, adipose-derived stem cells (ASCs) differentiated into SCs (SC-ASCs) were considered as promising cell therapy. However, the cell trans-differentiation process has not been effectively showed and presents several drawbacks, thus an alternative approach for increasing ASCs neurotrophic properties is highly demanded. In the context of human cell-based therapies, Good Manufacturing Practice directions indicate that FBS should be substituted with a xenogeneic-free supplement, such as Human Platelet Lysate (HPL). Previously, we demonstrated that neurotrophic properties of HPL-cultured ASCs were superior compared to undifferentiated FBS-cultured ASCs. Therefore, as following step, here we compared the neurotrophic properties of differentiated SC-like ASCs and HPL-cultured ASCs.MethodsBoth cell groups were investigated for gene expression level of neurotrophic factors, their receptors and neuronal markers. Moreover, the expression of nestin was quantitatively evaluated by flow cytometry. The commitment toward the SC phenotype was assessed with immunofluorescence pictures. Proteomics analysis was performed on both cells and their conditioned media to compare the differential protein profile. Finally, neurotrophic abilities of both groups were evaluated with a functional co-culture assay, assessing dorsal root ganglia survival and neurite outgrowth.ResultsHPL-cultured ASCs demonstrated higher gene expression of NGF and lower expression of S100B. Moreover, nestin was present in almost all HPL-cultured ASCs and only in one quarter of SC-ASCs. Immunofluorescence confirmed that S100B was not present in HPL-cultured ASCs. Proteomics analysis validated the higher expression of nestin and the increase in cytoskeletal and ECM proteins involved in neural regeneration processes. The co-culture assay highlighted that neurite outgrowth was higher in the presence of HPL-ASCs or their conditioned medium compared to SC-ASCs.ConclusionsAll together, our results show that HPL-ASCs were more neurotrophic than SC-ASCs. We highlighted that the HPL triggers an immature neuro-induction state of ASCs, while keeping their stem properties, paving the way for innovative therapies for nerve regeneration.Graphical

Cryptolepine Suppresses Colorectal Cancer Cell Proliferation, Stemness, and Metastatic Processes by Inhibiting WNT/β-Catenin Signaling.

Colorectal cancer (CRC) is the third most frequent cancer and the second leading cause of cancer-related deaths globally. Evidence shows that over 90% of CRC cases are initiated by a deregulated Wingless Integrated Type-1 (WNT)/β-catenin signaling pathway. The WNT/β-catenin pathway also promotes CRC cell proliferation, stemness, and metastasis. Therefore, modulators of the WNT/β-catenin pathway may serve as promising regimens for CRC. This study investigated the effect of cryptolepine-a plant-derived compound-on the WNT/β-catenin pathway in CRC. Two CRC cell lines, COLO205 and DLD1, were treated with cryptolepine or XAV 939 (a WNT inhibitor) in the presence or absence of WNT3a (a WNT activator). Using a tetrazolium-based assay, cryptolepine was found to reduce cell viability in a dose- and time-dependent manner and was a more potent inhibitor of viability than XAV 939. RT-qPCR analyses showed that cryptolepine reverses WNT3a-induced expression of β-catenin, c-MYC, and WISP1, suggesting that cryptolepine inhibits WNT3a-mediated activation of WNT/β-catenin signaling. Cryptolepine also repressed WNT3a-induced OCT4 and CD133 expression and suppressed colony formation of the cells, indicating that cryptolepine inhibits the stemness of CRC cells. Additionally, cryptolepine inhibited WNT3a-induced epithelial-to-mesenchymal transition by reducing the expression of SNAI1 and TWIST1 genes. In a wound healing assay, cryptolepine was found to suppress cell migration under unstimulated and WNT3a-stimulated conditions. Moreover, cryptolepine downregulated WNT3a-induced expression of MMP2 and MMP9 genes, which are involved in cancer cell invasion. Altogether, cryptolepine suppresses CRC cell proliferation, stemness, and metastatic properties by inhibiting WNT3a-mediated activation of the WNT/β-catenin signaling pathway. These findings provide a rationale for considering cryptolepine as a potential WNT inhibitor in CRC.

Potential Natural Products Regulation of Molecular Signaling Pathway in Dermal Papilla Stem Cells.

Stem cells have demonstrated significant potential for tissue engineering and repair, anti-aging, and rejuvenation. Hair follicle stem cells can be found in the dermal papilla at the base of the follicle and the bulge region, and they have garnered increased attention because of their potential to regenerate hair as well as their application for tissue repair. In recent years, these cells have been shown to affect hair restoration and prevent hair loss. These stem cells are endowed with mesenchymal characteristics and exhibit self-renewal and can differentiate into diverse cell types. As research in this field continues, it is probable that insights regarding stem cell maintenance, as well as their self-renewal and differentiation abilities, will benefit the application of these cells. In addition, an in-depth discussion is required regarding the molecular basis of cellular signaling and the influence of nature-derived compounds in stimulating the stemness properties of dermal papilla stem cells. This review summarizes (i) the potential of the mesenchymal cells component of the hair follicle as a target for drug action; (ii) the molecular mechanism of dermal papilla stem cells for maintenance of their stem cell function; and (iii) the positive effects of the natural product compounds in stimulating stemness in dermal papilla stem cells. Together, these insights may help facilitate the development of novel effective hair loss prevention and treatment.

Interferon-Alpha Decreases Cancer Stem Cell Properties and Modulates Exosomes in Malignant Melanoma.

Malignant melanoma (MM) can spread to other organs and is resistant in part due to the presence of cancer stem cell subpopulations (CSCs). While a controversial high dose of interferon-alpha (IFN-α) has been used to treat non-metastatic high-risk melanoma, it comes with undesirable side effects. In this study, we evaluated the effect of low and high doses of IFN-α on CSCs by analyzing ALDH activity, side population and specific surface markers in established and patient-derived primary cell lines. We also assessed the clonogenicity, migration and tumor initiation capacities of IFN-α treated CSCs. Additionally, we investigated genomic modulations related to stemness properties using microRNA sequencing and microarrays. The effect of IFN-α on CSCs-derived exosomes was also analyzed using NanoSight and liquid chromatography (LC-HRMS)-based metabolomic analysis, among others. Our results showed that even low doses of IFN-α reduced CSC formation and stemness properties, and led to a significant decrease in the ability to form tumors in mice xenotransplants. IFN-α also modulated the expression of genes and microRNAs involved in several cancer processes and metabolomics of released exosomes. Our work suggests the utility of low doses of interferon, combined with the analysis of metabolic biomarkers, as a potential clinical approach against the aggressiveness of CSCs in melanoma.

Loss of miR-6844 alters stemness/self-renewal and cancer hallmark(s) markers through CD44-JAK2-STAT3 signaling axis in breast cancer stem-like cells.

MicroRNAs regulate breast stemness and self-renewal properties in breast cancer cells at the molecular level. Recently we reported the clinical relevance and in vitro expression profile of novel miR-6844 in breast cancer and -derived stem-like cells (mammosphere). In the present study, we first time explore the functional role of loss of miR-6844 in breast cancer cells derived mammosphere. Down expression of miR-6844 significantly decreased cell proliferation in MCF-7 and T47D cells derived mammosphere in a time-dependent manner. MiR-6844 down expression reduced the sphere formation in terms of size and number in test cells. Loss of miR-6844 significantly altered stemness and self-renewal markers (Bmi-1, Nanog, c-Myc, Sox2, and CD44) in mammosphere compared to negative control spheres. Moreover, loss of miR-6844 inhibits the JAK2-STAT3 signaling pathway by decreasing p-JAK2 and p-STAT3 levels in breast cancer cells derived mammosphere. Loss of miR-6844 expression significantly decreased CCND1 and CDK4 mRNA/protein levels and arrested breast cancer stem-like cells in G2/M phase. Reduced expression of miR-6844 increased Bax/Bcl-2 ratio, late apoptotic cell population, and Caspase 9 and 3/7 activity in the mammosphere. Low expression of miR-6844 decreased migratory and invasive cells by altering the expression of Snail, E-cad, and Vimentin at mRNA/protein levels. In conclusion, loss of miR-6844 decreases stemness/self-renewal and other cancer hallmark in breast cancer stem-like cells through CD44-JAK2-STAT3 axis. Thus, downregulation of miR-6844 by therapeutic agents might be a novel strategy to target breast cancer stemness and self-renewal.

Body fluid-derived stem cells - an untapped stem cell source in genitourinary regeneration.

Somatic stem cells have been obtained from solid organs and tissues, including the bone marrow, placenta, corneal stroma, periosteum, adipose tissue, dental pulp and skeletal muscle. These solid tissue-derived stem cells are often used for tissue repair, disease modelling and new drug development. In the past two decades, stem cells have also been identified in various body fluids, including urine, peripheral blood, umbilical cord blood, amniotic fluid, synovial fluid, breastmilk and menstrual blood. These body fluid-derived stem cells (BFSCs) have stemness properties comparable to those of other adult stem cells and, similarly to tissue-derived stem cells, show cell surface markers, multi-differentiation potential and immunomodulatory effects. However, BFSCs are more easily accessible through non-invasive or minimally invasive approaches than solid tissue-derived stem cells and can be isolated without enzymatic tissue digestion. Additionally, BFSCs have shown good versatility in repairing genitourinary abnormalities in preclinical models through direct differentiation or paracrine mechanisms such as pro-angiogenic, anti-apoptotic, antifibrotic, anti-oxidant and anti-inflammatory effects. However, optimization of protocols is needed to improve the efficacy and safety of BFSC therapy before therapeutic translation.

Prolyl 4-hydroxylase P4HA1 Mediates the Interplay Between Glucose Metabolism and Stemness in Pancreatic Cancer Cells.

Cancer stem cells (CSCs) are profoundly implicated in tumor initiation and progression as well as drug resistance and tumor recurrence of many cancer types, especially pancreatic ductal adenocarcinoma (PDAC). Previously, we revealed that prolyl 4-hydroxylase subunit alpha 1 (P4HA1) enhances the Warburg effect and tumor growth in PDAC. However, the possible connection between P4HA1 and cancer stemness in PDAC remains obscure. In this study, P4HA1-dependent cancer stemness was studied by sphere-formation assay and detection of stemness markers. Glycolytic capacity in cancer stem cells and their parental tumor cells was investigated by glucose uptake, lactate secretion, and expression of glycolytic genes. Glycolysis inhibitors were used to determine the link between cancer stemness and glycolysis. A subcutaneous xenograft model was generated to investigate P4HA1-induced stemness and glycolysis in vivo. We revealed that ectopic expression of P4HA1 increased the stemness of PDAC cells as evidenced by the increased proportion of CD133+ cells, elevated sphere-formation ability, and the upregulated levels of cancer stemness-related proteins (SOX2, OCT4, and NANOG). Blocking tumor glycolysis with 2-Deoxy-D-glucose (2-DG) or a selective inhibitor of glucose transporter 1 (STF-31) significantly reduced the stem properties of PDAC cells, suggesting that P4HA1-induced glycolysis was essential for the stem-like phenotype of PDAC cells. In addition, in vivo study reaffirmed a promotive effect of P4HA1 on tumor glycolysis and cancer stemness. Collectively, our findings suggest that P4HA1 not only affects tumor metabolic reprogramming but also facilitates cancer stemness, which might be exploited as a vulnerable target for PDAC treatment.

The lncRNA RMST is drastically downregulated in anaplastic thyroid carcinomas where exerts a tumor suppressor activity impairing epithelial-mesenchymal transition and stemness

Thyroid cancer is the most prevalent endocrine malignancy and comprises a wide range of lesions subdivided into differentiated (DTC) and undifferentiated thyroid cancer (UTC), mainly represented by the anaplastic thyroid carcinoma (ATC). This is one of the most lethal malignancies in humankind leading invariably to patient death in few months. Then, a better comprehension of the mechanisms underlying the development of ATC is required to set up new therapeutic approaches. Long non-coding RNAs (lncRNAs) are transcripts over 200 nucleotides in length that do not code for proteins. They show a strong regulatory function at both transcriptional and post-transcriptional level and are emerging as key players in regulating developmental processes. Their aberrant expression has been linked to several biological processes, including cancer, making them potential diagnostic and prognostic markers. We have recently analyzed the lncRNA expression profile in ATC through a microarray technique and have identified rhabdomyosarcoma 2-associated transcript (RMST) as one of the most downregulated lncRNA in ATC. RMST has been reported to be deregulated in a series of human cancers, to play an anti-oncogenic role in triple-negative breast cancer, and to modulate neurogenesis by interacting with SOX2. Therefore, these findings prompted us to investigate the role of RMST in ATC development. In this study we show that RMST levels are strongly decreased in ATC, but only slightly in DTC, indicating that the loss of this lncRNA could be related to the loss of the differentiation and high aggressiveness. We also report a concomitant increase of SOX2 levels in the same subset of ATC, that inversely correlated with RMST levels, further supporting the RMST/SOX2 relationship. Finally, functional studies demonstrate that the restoration of RMST in ATC cells reduces cell growth, migration and the stemness properties of ATC stem cells. In conclusion, these findings support a critical role of RMST downregulation in ATC development.

Shakedown theorems for shape memory alloys structures with functional fatigue — Application to nitinol stents

Shape memory alloys (SMAs) offer interesting perspectives in various fields such as aeronautics, robotics, biomedical sciences, or structural engineering. The distinctive properties of those materials stem from a solid/solid phase transformation occurring at a microscopic level. Modeling the rather complex behavior of SMAs is a topic of active research. Lately, SMA models coupling phase-transformation with permanent inelasticity have been proposed to capture degradation effects which are frequently observed experimentally for cyclic loadings — a phenomenon referred to as functional fatigue. In this paper, the classical static and kinematic shakedown of plasticity theory are extended to such material models. Those results give conditions for the energy dissipation to remain bounded, which is beneficial for the fatigue life. Analytical shakedown limits are obtained for a 3-bar truss example and compared with numerical results from step-by-step simulations. We consider the problem of a nitinol stent submitted to cyclic pressure and mixed pressure–bending as an application, showing how the approach presented can be combined with finite-element analysis to study shakedown of complex 3D structures.

Role of POU1F1 promoting the properties of stemness of gastric carcinoma through ENO1-mediated glycolysis reprogramming.

Cancer stem cells (CSCs), a rare subset of tumor cells, have been recognized as promotive role on tumor initiation and propagation. Among, aerobic glycolysis, widely clarified in multiple tumor cells, is the key for maintaining cancer stemness. Regrettably, it is largely unknown about the connection of cellular metabolic reprogramming and stemness in gastric carcinoma (GC). Two GC parental cells lines PAMC-82 and SNU-16 and their spheroids were obtained to determine the expression status of POU1F1 using quantitative real-time PCR (qRT-PCR) and western blotting analysis, respectively. Gain or loss-of-function assay was employed to assess its biological effects. Sphere formation and transwell assays were performed to evaluate the stem cell-like traits, including self-renewal capacity, migration and invasion. Chromatin immunoprecipitation (ChIP) and luciferase reporter assays were conducted for determining the binding relationship of POU1F1 on ENO1 promoter region. Herein, aberrantly upregulated POU1F1 was observed in spheroids, compared with the parental PAMC-82 and SNU-16 cells, which promoted stem cell-like traits, as representing increasing sphere formation, enhanced cell migration and invasion. Additionally, POU1F1 expression was positively with glycolytic signaling, as displaying increasing glucose consumption, lactic acid production, and extracellular acid ratio (ECAR). Furthermore, POU1F1 was identified to be a transcriptional activator of ENO1, of which overexpression remarkably abolished POU1F1 knockdown-mediated blocking effects. Taken together, we draw a conclusion that POU1F1 facilitated the stem cell-like properties of GC cells through transcriptionally augmenting ENO1 to enhance glycolysis.

Pleckstrin homology and RhoGEF domain containing G4 (PLEKHG4) leads to the activation of RhoGTPases promoting the malignant phenotypes of thyroid cancer.

Thyroid cancer (TC) is one of the most common endocrine system cancers, and its incidence is elevating. There is an urgent need to develop a deeper understanding of TC pathogenesis and explore new therapeutic target for its treatment. This study aimed to investigate the effects of pleckstrin homology and RhoGEF domain containing G4 (PLEKHG4) on the progression of TC. Herein, 29 pairs of TC and adjacent tissues were used to assess the expression of PLEKHG4. A xenograft model of mouse was established by subcutaneously injected with TC cells. Lung metastasis model was established through left ventricular injection. The results revealed that PLEKHG4 was up-regulated in human TC tissues. PLEKHG4 level was correlated with clinicopathological parameters of TC patients. In vitro assays revealed that PLEKHG4 promoted TC cell proliferation, migration, invasion, and epithelial-mesenchymal transformation. Knockdown of PLEKHG4 led to the opposite effects, and the loss of PLEKHG4 enhanced the apoptosis ability and inhibited the stemness properties of TC cells. These findings were further confirmed by the in vivo growth and lung metastasis of TC tumor. Mechanistically, PLEKHG4 promoted the activation of RhoGTPases RhoA, Cdc42, and Rac1. The inhibitors of these RhoGTPases reversed the PLEKHG4-induced malignant phenotypes. Additionally, ubiquitin-conjugating enzyme E2O (UBE2O), a large E2 ubiquitin-conjugating enzyme acted as an ubiquitin enzyme of PLEKHG4, facilitated its ubiquitination and degradation. In conclusion, PLEKHG4, regulated by UBE2O, promoted the thyroid cancer progression via activating the RhoGTPases pathway. UBE2O/PLEKHG4/RhoGTPases axis is expected to be a novel a therapeutic target for TC treatment.

Lysine demethylase 3A promotes chondrogenic differentiation of aged human dental pulp stem cells

Background/purposeAging severely impairs the beneficial effects of human dental pulp stem cells (hDPSCs) on cartilage regeneration. Lysine demethylase 3A (KDM3A) is involved in regulating mesenchymal stem cells (MSCs) senescence and bone aging. In this study, we investigated the role of KDM3A in hDPSCs aging and whether KDM3A could rejuvenate aged hDPSCs to enhance their chondrogenic differentiation capacity. Materials and methodsThe cellular aging of hDPSCs was evaluated by senescence-associated β-galactosidase (SA-β-gal) staining. Protein levels were determined using Western blot analysis. KDM3A was overexpressed in aged hDPSCs by lentivirus infection. Quantitative reverse-transcription polymerase chain reaction (RT-qPCR) were used to determine the mRNA levels of stemness markers. Toluidine blue staining was used to evaluate the effect of KDM3A overexpression on the chondrogenic differentiation of aged hDPSCs. ResultshDPSCs at passage 12 or treated with etoposide exhibited augmented cellular senescence as evidenced by increased SA-β-gal activity. KDM3A was significantly increased during senescence of hDPSCs. Overexpression of KDM3A did not affect the stemness properties but significantly promoted the chondrogenic differentiation of aged hDPSCs. ConclusionOur findings indicate that KDM3A plays an important role in the maintenance of the chondrogenic differentiation capacity of aged hDPSCs and suggest that therapies targeting KDM3A may be a novel strategy to rejuvenate aged hDPSCs.

Abstract B005: The oncogenic transcription factor ERG has distinct roles and signaling regulation in different prostate cancer cell types

Abstract Background: ERG is the most common oncogene in prostate cancer, as it is aberrantly expressed in about 50% of cases due to the TMPRSS2/ERG gene rearrangement. ERG is not normally expressed in the adult prostate. The normal function of ERG is confined to hematopoietic stem cells and blood vessels. Aberrant expression of ERG in prostate epithelial cells is oncogenic when combined with mutations that activate the PI3K/AKT signaling pathway. The RAS/MAPK pathway can also regulate ERG function through direct phosphorylation of ERG by ERK. The function of these regulatory events and how they can be exploited to develop therapy for ERG-positive prostate cancer remains unclear. Results: ERG expression in prostate basal epithelial cells drives epithelial to mesenchymal transition and stemness properties. This function requires ERG phosphorylation via a positive feedback loop with the TLR4 signaling pathway, and can be repressed by a TLR4 inhibitor. Activation of the PI3K/AKT pathway rearranges the ERG cistrome and alters ERG function, where ERG now promotes luminal epithelial differentiation. In the presence of activated AKT, new ERG targets include genes involved in vascular development and ERG phosphorylation is regulated through a positive feedback loop with the VEGF signaling pathway. Conclusions: ERG function in basal and luminal prostate epithelial cells appear to mirror ERG functions in hematopoietic stem cells and blood vessels, respectively. These findings suggest strategies of combinatorial inhibition of ERG function in both cell types. Citation Format: Peter C. Hollenhorst, Saranya Rajendran, Travis J. Jerde. The oncogenic transcription factor ERG has distinct roles and signaling regulation in different prostate cancer cell types [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr B005.