Marrow-derived Mesenchymal Stem Cells Research Articles

Engineering Biomimetic Microvascular Capillary Networks in Hydrogel Fibrous Scaffolds via Microfluidics-Assisted Co-Axial Wet-Spinning.

The microvascular bed plays a crucial role in establishing nutrient exchange and waste removal, as well as maintaining tissue metabolic activity in the human body. However, achieving microvascularization of engineered 3D tissue constructs is still an unsolved challenge. In this work, we developed biomimetic cell-laden hydrogel microfibers recapitulating oriented microvascular capillary-like networks by using a 3D bioprinting technique combined with microfluidics-assisted coaxial wet-spinning. Highly packed and aligned bundles embedding a coculture of human bone marrow-derived mesenchymal stem cells (MSCs) and human umbilical vein endothelial cells (HUVECs) were produced by simultaneously extruding two different bioinks. To this aim, core-shell fibers were wet-spun in a coagulation bath to collect the scaffolds later on a rotary drum. Initially, the versatility of the proposed system was assessed for the extrusion of multimaterial core-shell hydrogel fibers. Subsequently, the platform was validated for the in vitro biofabrication of samples promoting optimal cell alignment along the fiber axis. After 3 weeks of culture, such fiber configuration resulted in the development of an oriented capillary-like network within the fibrin-based core and in the endothelial-specific CD31 marker expression upon MSC/HUVEC maturation. Synergistically, the vertical arrangement of the coaxial nozzle coupled with the rotation of the fiber collector facilitated the rapid creation of tightly packed bundles characterized by a dense, oriented, and extensively branched capillary network. Notably, such findings suggest that the proposed biofabrication strategy can be used for the microvascularization of tissue-specific 3D constructs.

Novel Gene Biomarkers Specific to Human Mesenchymal Stem Cells Isolated from Bone Marrow.

In this paper, we present a comparative analysis of the transcriptomic profile of three different human cell types: hematopoietic stem cells (HSCs), bone marrow-derived mesenchymal stem cells (MSCs) and fibroblasts (FIBs). The work aims to identify unique genes that are differentially expressed as specific markers of bone marrow-derived MSCs, and to achieve this undertakes a detailed analysis of three independent datasets that include quantification of the global gene expression profiles of three primary cell types: HSCs, MSCs and FIBs. A robust bioinformatics method, called GlobalTest, is used to assess the specific association between one or more genes expressed in a sample and the outcome variable, that is, the 'cell type' provided as a single univariate response. This outcome variable is predicted for each sample tested, based on the expression profile of the specific genes that are used as input to the test. The precision of the tests is calculated along with the statistical sensitivity and specificity for each gene in each dataset, yielding four genes that mark MSCs with high accuracy. Among these, the best performer is the protein-coding gene Transgelin (TAGLN, Gene ID: 6876) (with a Positive Predictive Value > 0.96 and FDR < 0.001), which identifies MSCs better than any of the currently used standard markers: ENG (CD105), THY1 (CD90) or NT5E (CD73). The results are validated by RT-qPCR, providing novel gene biomarkers specific for human MSCs.

An Update on Emerging Regenerative Medicine Applications: The Use of Extracellular Vesicles and Exosomes for the Management of Chronic Pain.

Chronic pain affects nearly two billion people worldwide, surpassing heart disease, diabetes, and cancer in terms of economic costs. Lower back pain alone is the leading cause of years lived with disability worldwide. Despite limited treatment options, regenerative medicine, particularly extracellular vesicles (EVs) and exosomes, holds early promise for patients who have exhausted other treatment options. EVs, including exosomes, are nano-sized structures released by cells, facilitating cellular communication through bioactive molecule transfer, and offering potential regenerative properties to damaged tissues. Here, we review the potential of EVs and exosomes for the management of chronic pain. In osteoarthritis, various exosomes, such as those derived from synovial mesenchymal stem cells, human placental cells, dental pulp stem cells, and bone marrow-derived mesenchymal stem cells (MSCs), demonstrate the ability to reduce inflammation, promote tissue repair, and alleviate pain in animal models. In intervertebral disc disease, Wharton's jelly MSC-derived EVs enhance cell viability and reduce inflammation. In addition, various forms of exosomes have been shown to reduce signs of inflammation in neurons and alleviate pain in neuropathic conditions in animal models. Although clinical applications of EVs and exosomes are still in the early clinical stages, they offer immense potential in the future management of chronic pain conditions. Clinical trials are ongoing to explore their therapeutic potential further, and with more research the potential applicability of EVs and exosomes will be fully understood.

Autologous Bone Marrow-Derived Mesenchymal Stem Cells in the Reversal of Unobstructed Azoospermia in Rats.

Non-obstructive azoospermia (NOA) is an important cause of male infertility. This study is being proposed to assess the efficacy of autologous bone marrow-derived mesenchymal stem cells (MSCs) in the reversal of busulfan-induced NOA in rats. Twenty adult 3-month-old male rats were divided into two groups: a control group and a study group. In the study group, bone marrow was aspirated to culture MSCs. NOA was created by stopping endogenous spermatogenesis in all the animals by injecting two doses of busulfan 10 mg/kg body weight with a 3week interval. Four weeks after the last dose of busulfan, two animals were euthanized and the testes were studied histologically to confirm complete azoospermia. In the study group, five million MSCs in 1 mL normal saline were injected into seminiferous tubules; and in the control group, 1 mL of normal saline was injected. After 4weeks of MSC injection, all the rats were euthanized and epididymis tails and testes were harvested and sent for measurement of serological indices, including luminal, cellular, and total diameters, luminal, cellular, and cross-sectional areas, number of tubules per unit area of testis, numerical density of the tubules, and spermatogenesis index, pre- and post-MSC transplantation. The effect of busulfan on the testicular tissue was universally devastating. In the control group, there was variable length and width of markedly necrotic seminiferous tubules, whereas in the group treated with autologous bone marrow-derived MSCs there was variable height of germinal epithelium in seminiferous tubules, with active spermatogenesis, showing spermatogonia, spermatocytes, and sperm. MSC injection in the testis has the potential to reverse the testicular function of spermatogenesis after cytotoxic therapy. Human trials should be undertaken to confirm our findings and bring the results into clinical practice.

Mesenchymal stem cell infusion for enhancing hematopoietic recovery and addressing cytopenias in CAR-T cell therapy

BackgroundChimeric antigen receptor (CAR)-T therapy has emerged as a promising treatment for hematologic malignancies. However, cytopenia remains one of the most frequent and challenging adverse effects of this therapy.MethodsWe conducted a retrospective analysis of 26 patients with relapsed/refractory aggressive B-cell lymphoma who received CAR-T therapy at our center. Subsequently, to investigate measures to address cytopenias following CAR-T therapy, we isolated and generated murine CAR-T cells and bone marrow-derived mesenchymal stem cells (MSCs), establishing a murine syngeneic CAR-T therapy model. We assessed the impact of MSC infusion on hematopoietic recovery post-CAR-T therapy by evaluating complete blood count, bone marrow hematopoietic stem cells and their subpopulations, bone marrow histomorphology, and hematopoiesis-related genes.ResultsAll patients experienced cytopenias to varying degrees, with complete lineage involvement in half of the patients. Grade ≥ 3 cytopenias were observed in 88.46% of the patients. CAR-T therapy was associated with a higher incidence of biphasic, late-onset, or prolonged cytopenias. Survival analysis indicated that neutropenia and lymphopenia tended to be associated with better prognosis, whereas thrombocytopenia tended to be related to poorer outcomes. Through animal experiments, we discovered that MSCs infusion boosted HSCs and their long-term subpopulations, enhancing hematopoietic recovery, particularly in the megakaryocyte lineage, and mitigating bone marrow damage. Importantly, both in vitro and in vivo experiments demonstrated that MSCs did not compromise the activity or antitumor efficacy of CAR-T cells.ConclusionsOur findings propose MSCs infusion as a promising strategy to address cytopenias, particularly thrombocytopenia, after CAR-T therapy. This approach could help overcome certain limitations of cellular immunotherapy by enhancing hematopoietic recovery without compromising the efficacy of CAR-T cells.HighlightsCytopenia is a frequently observed adverse effect following CAR-T therapy, and it is often characterized by biphasic and prolonged patterns.MSCs play a critical role in promoting hematopoietic recovery and mitigating bone marrow damage in a murine model of CAR-T therapyThe activity and antitumor efficacy of CAR-T cells were not impaired by MSCs.Graphical

Effect of Adeno-Associated Virus-Transfected Mesenchymal Stem Cells Containing Agents On Bone Formation in Extended İnter-Premaxillary Suture in Rats

Aim: The aim of this study was to investigate the histomorphometric effects of bone marrow-derived mesenchymal stem cells (MSCs) transfected with Adeno Associated Virus (AAV) and containing bone morphogenic protein 7 (Bmp7) or osteoprotegerin (OPG) on bone formation after injection into inter-premaxillary suture in rats with Bmp7 or OPG alone. Materials and methods: In 4 groups (each group n:9), different chemical solutions, namely AAV-Bmp7, AAV-OPG and AAV-Bmp7-OPG and AAV-EGF (control group) were injected into the interpremaxillary suture of rats. Bone volumes (BV), soft tissue volume (STV) and total bone volumes (TBV) of 10 μm serial selection with hemotoxylin and eosin staining were calculated according to the Cavalieri principle. Each point in the region of interest was 1000μm3. Results: The BV for AAV-Bmp7, AAV-OPG, AAV-Bmp7-OPG and AAV-EGF were 46.98±1.50 mm3, 49.40±4.72 mm3, 42.58±2.89 mm3 and 38.82±0.76 mm3, respectively. The STV was 11.53±0.99, 13.31±1.88, 8.00±4.43 and 9.57±1.90 mm3 for Bmp7, OPG, AAV-Bmp7-OPG and AAV-EGF, respectively. TBV was 58.34±2.28 mm3, 63.83±5.17 mm3, 53.74±3.34 mm3 and 48.13±1.54 mm3 for AAV-Bmp7, AAV-OPG, AAV-Bmp7-OPG and AAV-EGF, respectively. The comparison between BV, STV, TBV for AAV-OPG showed a statistically significant difference (p=0.001) compared to AAV-Bmp7 or AAV-Bmp7-OPG and AAV-EGF. Conclusion: During tooth movement and bone remodeling, the ratio of soft and bone tissues is maintained by OPG. Although Bmp7 is not as effective as OPG in bone remodeling, both can reduce the retention time and the risk of recurrence.

Small Molecule-Mediated Stage-Specific Reprogramming of MSCs to Hepatocyte-Like Cells and Hepatic Tissue for Liver Injury Treatment

BackgroundDerivation of hepatocytes from stem cells has been established through various protocols involving growth factor (GF) and small molecule (SM) agents, among others. However, mesenchymal stem cell-based derivation of hepatocytes still remains expensive due to the use of a cocktail of growth factors, and a long duration of differentiation is needed, thus limiting its potential clinical application.MethodsIn this study, we developed a chemically defined differentiation strategy that is exclusively based on SM and takes 14 days, while the GF-based protocol requires 23–28 days.ResultsWe optimized a stage-specific differentiation protocol for the differentiation of rat bone marrow-derived mesenchymal stem cells (MSCs) into functional hepatocyte-like cells (dHeps) that involved four stages, i.e., definitive endoderm (DE), hepatic competence (HC), hepatic specification (HS) and hepatic differentiation and growth. We further generated hepatic tissue using human decellularized liver extracellular matrix and compared it with hepatic tissue derived from the growth factor-based protocol at the transcriptional level. dHep, upon transplantation in a rat model of acute liver injury (ALI), was capable of ameliorating liver injury in rats and improving liver function and tissue damage compared to those in the ALI model.ConclusionsIn summary, this is the first study in which hepatocytes and hepatic tissue were derived from MSCs utilizing a stage-specific strategy by exclusively using SM as a differentiation factor.Graphical

Inhibition Effect of Resveratrol on Spontaneous Senescence of Human Bone Marrow Derived Mesenchymal Stem Cells

To explore whether Resveratrol (RSV) can inhibit the spontaneous senescence of human bone marrow-derived mesenchymal stem cells (MSC). MSC were serially cultured to passage 13 and passage 15 to establish model groups exhibiting spontaneous senescence, respectively. MSC at passage 13 and passage 15 were treated with 5 nmol/L RSV for 48 h to establish the RSV-treated groups. SA-β-Gal staining was used to detect cell senescence. MTT assay was used to detect cell proliferation. RT-PCR method was used to detect senescenceassociated telomerase activity. Western blot was used to detect the senescence-associated protein level of the phosphorylated-mTOR. SA-β-Gal staining showed that the senescent cells of MSC in RSV-treated group was significantly less than those in the model group (RSV group compared with model group at passage 13, P < 0.05; RSV group compared with model group at passage 15, P < 0.01). The cell proliferation ability of MSC in RSV-treated group was significantly higher than those in model group, at 72 h in passage 13, there was significant difference between RSV-treated group and model group (P < 0.05). RT-PCR results showed that the hTERT mRNA expression of MSC in RSV-treated group was higher than that in model group, which was significantly different between RSV-treated group and model group at passage 13 (P < 0.05). Western blot results showed that the phosphorylated (Ser2448)-mTOR level of MSC in RSV-treated group was lower than that in model group, which was significantly different between RSV-treated group and model group at passage 13 (P < 0.05). RSV can inhibit the spontaneous senescence of human MSC by mediating mTOR activity.

Advancing cellular insights: Super-resolution STORM imaging of cytoskeletal structures in human stem and cancer cells

Fluorescence microscopy is an important tool for cell biology and cancer research. Present-day approach of implementing advanced optical microscopy methods combined with immunofluorescence labelling of specific proteins in cells is now able to deliver optical super-resolution up to ∼25 nm. Here we perform super-resolved imaging using standard immunostaining protocol combined with easy stochastic optical reconstruction microscopy (easySTORM) to observe structural differences of two cytoskeleton elements, actin and tubulin in three different cell types namely human bone marrow-derived mesenchymal stem cells (MSCs), human glioblastoma (U87MG) and breast cancer (MDAMB-231) cells. The average width of the actin bundle obtained from STORM images of stem cells is observed to be larger than the same for U87MG and MDAMB-231 cells. No significant difference is however noticed in the width of the tubulin within the same cells. We also study the functional effect on the 2D migration potential of MDAMB-231 cells silenced for NICD1 and β-catenin. Although similar migration speed is observed for cells with the above two conditions compared to their control cells, easySTORM images show that widths of the actin in MDAMB-231 cells in β-catenin silenced is significantly lower than the same in control cells. Such minute differences however are not observable in widefield images. The outcome of our easySTORM investigation should benefit the researchers carrying out detailed investigations of the cellular structure and potential therapeutic applications.

Bioengineer mesenchymal stem cell for treatment of glioma by IL‐12 mediated microenvironment reprogramming and nCD47‐SLAMF7 mediated phagocytosis regulation of macrophages

AbstractHigh expression of cellular self‐activated immunosuppressive molecules and extensive infiltration of suppressive immune cells in the tumor microenvironment are the main factors contributing to glioma's resistance to immunotherapy. Nonetheless, technology to modify the expression of glioma cellular self‐molecules through gene editing requires further development. This project advances cell therapy strategies to reverse the immunosuppressive microenvironment of glioma (TIME). Bone marrow‐derived mesenchymal stem cells (MSCs) are engineered to express bioactive proteins and demonstrate tumor‐homing characteristics upon activation by TGF‐β. These MSCs are designed to secrete the anti‐tumor immune cytokine IL‐12 and the nCD47‐SLAMF7 fusion protein, which regulates T‐cell activity and macrophage phagocytosis. The engineered MSCs are then injected in situ into the glioma site, circumventing the blood‐brain barrier to deliver high local concentrations of bioactive proteins. This approach aims to enhance the M1 polarization of infiltrating macrophages, stimulate macrophage‐mediated tumor cell phagocytosis, activate antigen‐presenting cells, and promote effector CD8+ T cell infiltration, effectively controlling glioma. Additionally, the engineered MSCs may serve as a universal treatment for other tumors that express TGF‐β at high levels. This study proposes a novel treatment strategy for the clinical management of glioma patients.

Therapeutic potential of urine-derived stem cells in renal regeneration following acute kidney injury: A comparative analysis with mesenchymal stem cells.

Acute kidney injury (AKI) is a common clinical syndrome with high morbidity and mortality rates. The use of pluripotent stem cells holds great promise for the treatment of AKI. Urine-derived stem cells (USCs) are a novel and versatile cell source in cell-based therapy and regenerative medicine that provide advantages of a noninvasive, simple, and low-cost approach and are induced with high multidifferentiation potential. Whether these cells could serve as a potential stem cell source for the treatment of AKI has not been determined. To investigate whether USCs can serve as a potential stem cell source to improve renal function and histological structure after experimental AKI. Stem cell markers with multidifferentiation potential were isolated from human amniotic fluid. AKI severe combined immune deficiency (SCID) mice models were induced by means of an intramuscular injection with glycerol. USCs isolated from human-voided urine were administered via tail veins. The functional changes in the kidney were assessed by the levels of blood urea nitrogen and serum creatinine. The histologic changes were evaluated by hematoxylin and eosin staining and transferase dUTP nick-end labeling staining. Meanwhile, we compared the regenerative potential of USCs with bone marrow-derived mesenchymal stem cells (MSCs). Treatment with USCs significantly alleviated histological destruction and functional decline. The renal function was rapidly restored after intravenous injection of 5 × 105 human USCs into SCID mice with glycerol-induced AKI compared with injection of saline. Results from secretion assays conducted in vitro demonstrated that both stem cell varieties released a wide array of cytokines and growth factors. This suggests that a mixture of various mediators closely interacts with their biochemical functions. Two types of stem cells showed enhanced tubular cell proliferation and decreased tubular cell apoptosis, although USC treatment was not more effective than MSC treatment. We found that USC therapy significantly improved renal function and histological damage, inhibited inflammation and apoptosis processes in the kidney, and promoted tubular epithelial proliferation. Our study demonstrated the potential of USCs for the treatment of AKI, representing a new clinical therapeutic strategy.

Transplantation of Mesenchymal Stem Cells Derived from Old Rats Improves Healing and Biomechanical Properties of Vaginal Tissue Following Surgical Incision in Aged Rats.

Pelvic floor dysfunction encompasses a group of disorders that negatively affect the quality of women's lives. These include pelvic organ prolapse (POP), urinary incontinence, and sexual dysfunction. The greatest risk factors for prolapse are increased parity and older age, with the largest group requiring surgical intervention being post-menopausal women over 65. Prolapse recurrence rates following surgery were reported to be as high as 30%. This may be attributed to ineffective healing in the elderly. Autologous stem cell transplantation during surgery may improve surgical results. In our previous studies, we showed that the transplantation of bone marrow-derived mesenchymal stem cells (MSCs) from young donor rats improved the healing of full-thickness vaginal surgical incision in the vaginal wall of old rats, demonstrated by both histological and functional analysis. In order to translate these results into the clinical reality of autologous MSC transplantation in elderly women, we sought to study whether stem cells derived from old donor animals would provide the same effect. In this study, we demonstrate that MSC transplantation attenuated the inflammatory response, increased angiogenesis, and exhibited a time-dependent impact on MMP9 localization. Most importantly, transplantation improved the restoration of the biomechanical properties of the vagina, resulting in stronger healed vaginal tissue. These results may pave the way for further translational studies focusing on the potential clinical autologous adjuvant transplantation of MSCs for POP repair for the improvement of surgical outcomes.

Autologous bone marrow derived mesenchymal stem cells are safe for the treatment of Achilles tendinopathy

Achilles tendinopathy is a disabling condition that affects more than 50% of runners. Pre-clinical studies in a large animal model of naturally-occurring tendinopathy similar to human Achilles tendinopathy has shown benefits of autologous bone marrow-derived mesenchymal stem cell (MSC) implantation. However, MSCs are advanced therapies medicinal products (ATMPs), with strict regulatory requirements. Guided by the regulator we carried out a first in man study to assess the safety and efficacy of autologous MSC injection in human patients with non-insertional Achilles tendinopathy. Ten patients, mean age 47 with mid-portion Achilles tendon pain and swelling for more than 6 months, underwent autologous cultured cell injections (median 12.2 × 106, range 5–19 × 106 cells) into their Achilles tendon. At 24 weeks follow-up, no serious adverse reactions or important medical events were observed. MOXFQ, EQ-5D-5L, and VISA-A scores improved clinically at 12 and 24 weeks. VAS pain improved increasingly at 6, 12 and 24 weeks. MOXFQ Pain and VISA-A Scores improved > 12 points from baseline to 24 weeks in 8 patients. Maximum anteroposterior tendon thickness as measured by greyscale US decreased by mean 0.8 mm at 24 weeks. This phase IIa study demonstrated the safety of autologous MSC injection for non-insertional Achilles tendinopathy and provides proof-of-concept of the technique in patients, all of whom had previously failed conservative treatments for chronic disease and leads the way for a larger randomised controlled trial.

Cadherin-6 is a novel mediator for the migration of mesenchymal stem cells to glioblastoma cells in response to stromal cell-derived factor-1.

Glioblastoma recruits various nontransformed cells from distant tissues. Although bone marrow-derived mesenchymal stem cells (MSCs) have been observed migrating to glioblastoma, the underlying mechanism driving MSC migration toward glioblastoma remains unclear. Tumor vascularity is critical in the context of recurrent glioblastoma and is closely linked to the expression of stromal cell-derived factor-1 (SDF-1). We demonstrated that cadherin-6 mediated MSC migration both toward SDF-1 and toward glioblastoma cells. Cadherin-6 knockdown resulted in the downregulation of MSCs capacity to migrate in response to SDF-1. Furthermore, MSCs with cadherin-6 knockdown exhibited impaired migration in response to conditioned media derived from glioblastoma cell lines (U87 and U373) expressing SDF-1, thus simulating the glioblastoma microenvironment. Moreover, MSCs enhanced the vasculogenic capacity of U87 cells without increasing the proliferation, cancer stem cell characteristics, or migration of U87. These results suggest that the current strategy of utilizing MSCs as carriers for antiglioblastoma drugs requires careful examination. Furthermore, cadherin-6 may represent a novel potential target for controlling the recruitment of MSCs toward glioblastoma.

Effect of Piezo1 Channel-Mediated Mechanotransduction on Osteogenic Differentiation and Interleukin-6 Secretion in Bone Mesenchymal Stem Cells Under Tensile Strain

Physical stimulation plays a crucial role in the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (MSCs). However, the mechanotransductive mechanisms remain uncleared. Recent studies have suggested that the Piezo1 channel is essential for transforming mechanical signals. Therefore, we investigate the Piezo1-mediated mechanisms in mechanical strain-regulated MSC osteogenic differentiation and release of proinflammatory cytokines. The tensile strain was applied to rat MSCs cultured in a monolayer to induce mechanical strain. The immuno-nanomagnetic bead enzyme-linked immunosorbent assay was employed to assess gene and protein expressions, as well as osteogenic biomarkers and interleukin-6 (IL-6) release, both in the presence or absence of a Piezo1 agonist/antagonist. Firstly, biophysical loading through mechanical strain was found to promote MSC osteogenic differentiation. Suppression of Piezo1 using GsMTx4 antagonist or transfection with Piezo1-siRNA effectively inhibited mechanical responses associated with osteogenic gene expressions and IL-6. Activation of Piezo1 by Yoda1 mimicked the effects induced by mechanical strain on osteogenic gene expressions and IL-6 release, which were associated with YAP activation, upregulation, and nuclear accumulation of β-catenin. In conclusion, these findings significantly enhance our understanding of MSC mechanotransduction and hold great promise for drug development to enhance skeletal mass.

Abstract 4291: Bai1 inhibition promotes ferroptosis of breast cancer cells to prevent tumor growth in human xenograft tumor models

Abstract The adhesion G-protein coupled- receptor 1 ADGRB1/Bai1 was identified as a phosphatidylserine receptor that cooperates with ELMO/Dock180/Rac to promote maximal engulfment of apoptotic cells. This function of Bai1 was also shown to promote myoblasts fusion. Cell-cell fusion has been demonstrated to occur in normal physiological functions as well as in diseases. Studies have shown in cancer that cell-cell fusion increases tumor heterogeneity, drug resistance, and metastasis as hybrids acquire new properties that allow them to migrate and proliferate at new sites. Activation of ELMO-Dock signaling pathway has been associated with breast cancer metastasis. Moreover, ELMO1 has been identified as a modifier of breast cancer risk for BRCA mutation carriers. Rac1 was also shown to be overexpressed in proliferative breast disease, preinvasive and invasive breast carcinoma as well as lymph node metastases. Our recent studies showed that breast cancer cell fusion with bone marrow-derived mesenchymal stem cells was modulated by hypoxic conditions and promoted by apoptosis. Our hypothesis is that hypoxia stress induced apoptosis activates the phosphatidylserine receptor Bai1, and it signals through the ELMO/DOCK180/Rac to promote breast cancer cell fusion-driven tumor heterogeneity and metastasis. In this study, we determined the ability of Bai1 depleted breast cancer cells to induce tumor growth in immunocompromised mice. We used Bai1 sgRNA to inhibit Bai1 expression in the breast cancer cell MDA-MB-231. These cells (1x 106) together with bone marrow-derived mesenchymal stem cells (MSCs) (1x 106) were injected into the fat pad of the breast of 15 NOD SCID female mice. Control mice (15) received the same cells with no inhibition of Bai1. The mice were monitored for eight weeks. We found that Bai1 inhibition significantly reduced tumor growth in these mice in the course of time (P&amp;lt;0.05). The average tumor weight was also significantly reduced when Bai1 was inhibited (P&amp;lt;0.001). RNA sequencing of tumors generated from these mice revealed a significant increase in the expression of genes driving ferroptosis and a reduction in critical oncogenes in the experiment group compared to the control group. These findings will be helpful in the development of new classes of drugs effective in breast cancer treatment. Grant Support The NIH/NIMHD grant 5U54MD015929-03, the Society for Investigative Dermatology (SID) Freinkel Diversity Fellowship, and NSF Award Notice for Award ID 2142465 (awarded to FNK). Citation Format: Felicite Kamdem Noubissi, Oluwatowin Odubanjo, Hung-Chung Huang, Brenda Ogle, Paul Tchounwou. Bai1 inhibition promotes ferroptosis of breast cancer cells to prevent tumor growth in human xenograft tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4291.

Fabrication of novel strontium-coated bioactive ceramic-glass (C2S(2P6)C2S) 3D-porous scaffold for the proliferation and osteogenic differentiation of bone marrow-derived mesenchymal stem cells

This study fabricated novel multilayer 3D-scaffolds by coating bioactive Calcium silicate (Ca2SiO4)/glass phase (calcium ultraphosphate, Ca2P6O17)/Ca2SiO4 (C2S(2P6)C2S) 3D scaffolds with strontium (Sr) for osteogenic differentiation of bone marrow-derived mesenchymal stem cells (MSCs). Hence, for the first time, C2S(2P6)C2S/Sr 3D-scaffolds were fabricated by sol-gel method and their characterization (X-Ray diffraction analysis (XRD), scanning electron microscopy (SEM) and Mercury Porosimetry), effect in MSCs proliferation (cytotoxicity and mRNA expression) and osteogenic differentiation (staining and mRNA expression) were evaluated. The porosity and SEM data showed that the porosity (31.66% for C2S(2P6)C2S and 32.14% for C2S(2P6)C2S/Sr), pore size (<300 μm) and microstructure were not altered between C2S(2P6)C2S and C2S(2P6)C2S/Sr 3D-scaffolds, respectively. MSCs proliferation rate was increased by C2S(2P6)C2S/Sr 3D-scaffold via upregulating c-Fos and TGF-β1 mRNA expression. Alizarin Red (calcium), von-kossa (calcium-phosphate) and alkaline phosphatase (ALP) staining were higher in differentiated MSCs cultured on C2S(2P6)C2S/Sr 3D scaffold than in control. The osteogenic stimulatory effect of C2S(2P6)C2S/Sr 3D scaffold could be justified by increasing osteogenic stimulatory genes such as collagen type-I, Runx2, osteocalcin and ALP expression in differentiated MSCs. Further, SEM images proved that the C2S(2P6)C2S/Sr 3D scaffold-cultured cells had unique morphology similar to biological tissues. Accordingly, this is the first report evidencing the MSC proliferative and osteogenic stimulatory ability of strontium-coated C2S(2P6)C2S 3D-scaffold, which greatly impacts future strategic therapies in dentistry and bone regeneration.

Periostin in Cancer-Associated Fibroblasts Promotes Esophageal Squamous Cell Carcinoma Progression by Enhancing Cancer and Stromal Cell Migration

Cancer-associated fibroblasts (CAFs) in the tumor microenvironment are involved in the progression of various cancers, including esophageal squamous cell carcinoma (ESCC). CAF-like cells were generated through direct co-culture of human bone marrow-derived mesenchymal stem cells, one of CAF origins, with ESCC cells. Periostin (POSTN) was found to be highly expressed in CAF-like cells. After direct co-culture, ESCC cells showed increased malignant phenotypes, such as survival, growth, and migration, as well as increased phosphorylation of Akt and extracellular signal-regulated kinase (Erk). Recombinant human POSTN activated Akt and Erk signaling pathways in ESCC cells, enhancing survival and migration. The suppression of POSTN in CAF-like cells by siRNA during direct co-culture also suppressed enhanced survival and migration in ESCC cells. In ESCC cells, knockdown of POSTN receptor integrin β4 inhibited Akt and Erk phosphorylation, and survival and migration increased by POSTN. POSTN also enhanced mesenchymal stem cell and macrophage migration and endowed macrophages with tumor-associated macrophage-like properties. Immunohistochemistry showed that high POSTN expression in the cancer stroma was significantly associated with tumor invasion depth, lymphatic and blood vessel invasion, higher pathologic stage, CAF marker expression, and infiltrating tumor-associated macrophage numbers. Moreover, patients with ESCC with high POSTN expression exhibited poor postoperative outcomes. Thus, CAF-secreted POSTN contributed to tumor microenvironment development. These results indicate that POSTN may be a novel therapeutic target for ESCC.

ZO-1 regulates the migration of mesenchymal stem cells in cooperation with α-catenin in response to breast tumor cells

sMesenchymal stem cells are recruited from the bone marrow into breast tumors, contributing to the creation of a tumor microenvironment that fosters tropism for breast tumors. However, the intrinsic mechanisms underlying the recruitment of bone marrow-derived mesenchymal stem cells (MSCs) into the breast tumor microenvironment are still under investigation. Our discoveries identified zonula occludens-1 (ZO-1) as a specific intrinsic molecule that plays a vital role in mediating the collective migration of MSCs towards breast tumor cells and transforming growth factor beta (TGF-β), which is a crucial factor secreted by breast tumor cells. Upon migration in response to MDA-MB-231 cells and TGF-β, MSCs showed increased formation of adherens junction-like structures (AJs) expressing N-cadherin and α-catenin at their cell-cell contacts. ZO-1 was found to be recruited into the AJs at the cell-cell contacts between MSCs. Additionally, ZO-1 collaborated with α-catenin to regulate AJ formation, dependently on the SH3 and GUK domains of the ZO-1 protein. ZO-1 knockdown led to the impaired migration of MSCs in response to the stimuli and subsequent downregulation of AJs formation at the cell-cell contacts during MSCs migration. Overall, our study highlights the novel role of ZO-1 in guiding MSC migration towards breast tumor cells, suggesting its potential as a new strategy for controlling and re-engineering the breast tumor microenvironment.

Mesenchymal Stem Cells Preconditioned with Hypoxia and Dexamethasone Promote Osteoblast Differentiation Under Stress Conditions.

Bone marrow-derived mesenchymal stem cells (MSCs), which are capable of differentiating into osteoblasts, are used in effective regenerative therapies. MSCs must be prompted to differentiate into osteoblasts for MSC transplantation to be effective. In this study, osteoblast differentiation markers involved in bone formation were evaluated to investigate the stress resistance of bone marrow-derived rat MSCs to dexamethasone and hypoxia and their ability to differentiate into osteoblasts. MSCs were allowed to differentiate into osteoblasts for 21 days in three different environments (dexamethasone treatment, hypoxic conditions [1% oxygen], or both). Osteoblast differentiation potential was evaluated according to alkaline phosphatase levels and a mineralisation assay. Immunofluorescence staining was used to determine the protein expression of the osteoblast differentiation markers type I collagen and osteopontin. MSCs differentiated into osteoblasts under hypoxic conditions but differentiated more slowly upon treatment with dexamethasone and dexamethasone plus hypoxia relative to the control. MSCs preconditioned with dexamethasone or hypoxia and then allowed to differentiate into osteoblasts under similar conditions differentiated comparably to control MSCs. MSCs that developed resistance to dexamethasone or hypoxia differentiated more quickly into osteoblasts than those that did not. The findings suggest that increasing the resistance of MSCs to stress by preconditioning them via dexamethasone or hypoxia exposure could result in more rapid differentiation into osteoblasts following transplantation.