Donor Cells Research Articles

Islet-antigen reactive B cells display a unique phenotype and BCR repertoire in autoantibody positive and recent-onset type 1 diabetes patients.

Autoreactive B cells play an important but ill-defined role in autoimmune type 1 diabetes (T1D). To better understand their contribution, we performed single cell gene and BCR-seq analysis on pancreatic islet antigen-reactive (IAR) B cells from the peripheral blood of nondiabetic (ND), autoantibody positive prediabetic (AAB), and recent-onset T1D individuals. We found that the frequency of IAR B cells was increased in AAB and T1D. IAR B cells from these donors had altered expression of B cell signaling, pro-inflammatory, infection, and antigen processing and presentation genes. Both AAB and T1D donors demonstrated a significant increase in certain heavy and light chain V genes, and these V genes were enriched in islet-reactivity. Public clones of IAR B cells were restricted almost entirely to AAB and T1D donors. IAR B cells were clonally expanded in the autoimmune donors, particularly the AAB group. Notably, a substantial fraction of IAR B cells in AAB and T1D donors appeared to be polyreactive, which was corroborated by analysis of recombinant monoclonal antibodies. These results expand our understanding of autoreactive B cell activation during T1D and identify unique BCR repertoire changes that may serve as biomarkers for increased disease risk.

CREG1 promotes bovine placental trophoblast cells exosome release by targeting IGF2R and participates in regulating organoid differentiation via exosomes transport

BackgroundPlacental exosomes are a kind of intercellular communication media secreted by placental cells during pregnancy, exosomogenesis and release are regulated by many secretory glycoproteins. CREG1 is a kind of secreted glycoprotein widely expressed in various organs and tissues of the body, which inhibits cell proliferation and enhances cell differentiation. The aim of this study was to explore the role of CREG1 in regulating exosomogenesis during the proliferation and differentiation of placental trophoblast cells in early pregnant dairy cows by targeting IGF2R and participating in regulating organoid differentiation via exosomes transport. MethodsMolecular biological methods were firstly used to investigate the expression patterns of CREG1, IGF2R and exosomal marker proteins in early placental development of pregnant dairy cows. Subsequently, the effects of CREG1 on the formation and release of bovine placental trophoblast (BTCs) derived exosomes by targeting IGF2R were investigated. Further, the effects of CREG1 on the change of gene expression patterns along with the transport of exosomes to recipient cells and participate in regulating the differentiation of organoids were explored. ResultsThe expression of CREG1, IGF2R and exosomal marker proteins increased with the increase of pregnancy months during the early evolution of placental trophoblast cells in dairy cows. Overexpression of Creg1 enhanced the genesis and release of exosomes derived from BTCs, while knocking down the expression of Igf2r gene not only inhibited the genesis of exosomes, but also inhibited the genesis and release of exosomes induced by overexpression of CREG1 protein. Interestingly, IGF2R can regulate the expression of CREG1 through reverse secretion. What's more, the occurrence and release of trophoblast-derived exosomes are regulated by CREG1 binding to IGF2R, which subsequently binds to Rab11. CREG1 can not only promote the formation and release of exosomes in donor cells, but also regulate the change of gene expression patterns along with the transport of exosomes to recipient cells and participate in regulating the early development of placenta. ConclusionsOur study confirmed that CREG1 is involved in the exosomogenesis and release of exosomes during the proliferation and differentiation of placental trophoblast cells in early pregnant dairy cows by targeting IGF2R, and is involved in the regulation of organoid differentiation through exosome transport.

Restoration of functional endometrium in an intrauterine adhesion rat model with endometrial stromal cells transplantation

BackgroundIntrauterine adhesion (IUA) as a prevalent gynecological disease is developed from infection or trauma. However, therapeutic strategies to repair damaged endometrium are relatively limited. Emerging studies have shed light on the crucial role of endometrial stromal cells (EnSCs) in the process of uterine endometrial regeneration. EnSCs isolated from the uterine endometrium have similar characteristics to mesenchymal stem cells (MSCs). However, it is still unknown whether EnSCs could be used as donor cells to treat IUA. The aim of this study was to evaluate the potential efficacy of EnSCs in treating rat IUA.MethodsHuman EnSCs were isolated from the endometrial tissue of healthy female donors and subjected to extensive expansion and culture in vitro. Immunofluorescence, flow cytometry, cell proliferation assay, trilineage differentiation experiment, and decidualization assay were used to characterize the biological properties of EnSCs. We evaluated the immunoregulatory potential of EnSCs by analyzing their secreted cytokines and conducting bulk RNA sequencing after IFN-γ treatment. After EnSCs were transplanted into the uterine muscle layer in IUA rats, their therapeutic effects and underlying mechanisms were analyzed using histological analysis, Q-PCR, fertility and pregnancy outcome assay, and transcriptome analysis.ResultsWe successfully isolated EnSCs from the endometrium of human donors and largely expanded in vitro. EnSCs exhibited characteristics of mesenchymal stem cells and retained responsiveness to sex hormones. Following IFN-γ stimulation, EnSCs upregulated the anti-inflammatory cytokines and activated immunosuppressive molecules. Xenogeneic transplantation of EnSCs successfully repaired injured endometrium and significantly restored the pregnancy rate in IUA rats. Mechanistically, the therapeutic effects of EnSCs on IUA endometrium functioned through anti-inflammation, anti-fibrosis and the secretion of regeneration factor.ConclusionsDue to their large expansion ability, immunoregulatory properties, and great potential in treating IUA, EnSCs, as a valuable source of donor cells, could offer a potential treatment avenue for injury-induced IUA.

Restoration of thymic T-cell development by bone marrow transplantation in mouse radiation lymphomagenesis.

Fractionated total body irradiation (TBI) with X-rays induces thymic lymphoma/leukemia (TL) in C57BL/6 mice. Radiation-induced mouse TL (RITL) can be prevented by bone marrow transplantation (BMT) of unirradiated BM cells. However, the mechanisms underlying the prevention of RITL with BMT remain unclear. Here, we show that BMT restores thymic T-cell differentiation in mice subjected to TBI. TBI (four times of 1.8Gy X-rays weekly) was conducted with C57BL/6 mice. BMT was performed immediately after the last irradiation of TBI in mice by transplantation of BM cells isolated from enhanced green fluorescence protein (eGFP) transgenic mice. Thymic cell numbers were drastically decreased in TBI and TBI + BMT mice compared to those in non-irradiated mice. Flow cytometry showed a dramatic decrease in double negative (DN, CD4-CD8-) thymocytes, especially DN2 (CD25+CD44+) and DN3 (CD25+CD44-) subpopulations, in the TBI mice on Day 10 after the last irradiation. In contrast, the DN2 and DN3 populations were recovered in TBI + BMT mice. Interestingly, these restored DN2 and DN3 cells mainly differentiated from eGFP-negative recipient cells but not from eGFP-positive donor cells, suggesting that transplanted BM cells may interact with recipient cells to restore thymic T-cell development in the RITL model. Taken together, our findings highlight the significance of restoring thymic T-cell differentiation by BMT in RITL prevention.

Hemoglobin Electrophoresis versus Kleihauer-Betke to Determine Bone Marrow Suppression in Fetuses Undergoing Intrauterine Transfusion.

Mainstay therapy for fetuses affected by maternal red cell alloimmunization is serial intrauterine transfusion (IUT). Testing to determine when fetal red cells have been replaced with donor cells historically involves the use of the Kleihauer-Betke (KB) test. Hemoglobin (Hgb) electrophoresis testing may be more rapid with a reduced cost of analysis. We aimed to determine the correlation between fetal Hgb electrophoresis versus the traditional KB test. This is a retrospective analysis of all alloimmunized singleton pregnancies undergoing IUT between January 1, 2021, and July 1, 2023. Maternal and fetal characteristics were collected along with the indication for IUT. A final fetal blood sample was obtained at the conclusion of each transfusion and sent for KB testing and Hgb electrophoresis. The primary outcome was the assessment of these parameters in their ability to predict the replacement of the fetal circulating red cell population with donor cells. Linear regression analysis and repeated measures analysis of variance were performed, and p-values less than 0.05 were considered significant. A total of 56 IUTs were performed in 16 patients. There were 39 (69.6%) final KB test values collected and compared with 30 (53.6%) final Hgb electrophoresis values. Hgb electrophoresis when compared with the KB test demonstrated a significant correlation (R 2 = 0.93; 95% confidence interval, 0.61-0.76; p < 0.001). This same finding held true when examining the correlation at each individual IUT as well. The final KB test and Hgb electrophoresis values significantly decreased with each transfusion (p = 0.003). A predominance of adult donor blood was noted by the third transfusion for both laboratory indices. Fetal Hgb electrophoresis obtained at the time of IUT demonstrates a significant correlation with the traditional KB test. · Fetal Hgb electrophoresis following IUT is underexplored. · Hgb electrophoresis is an automated evaluation. · The traditional KB test is a manual evaluation. · These two tests demonstrate significant correlation.

Facilitating the ethical sourcing of donor hematopoietic stem cells for cell and gene therapy research and development.

Aim: Unrelated stem cell donor registries (DRs) are increasingly engaging in the field of cell and gene therapy (CGT). This study aims to explore the values, concerns, needs and expectations of donors and members of the public on donating hematopoietic stem cells (HSCs) for CGT.Methods: Seven focus groups were conducted in 2019 with members of the public, prospective donors and donors on the Anthony Nolan DR in the UK.Results: Participants expressed concerns over increased frequency of donation and incidental findings and required more information on the type of research including the purpose and possible outcomes.Conclusion: Addressing donors' concerns, needs and expectations on donating cellular materials for CGT research and development is essential to maintaining the highest standards for donor care and safety within this rapidly emerging field.

Spermatogonial stem cells in the 129 inbred strain exhibit unique requirements for self-renewal.

Spermatogonial stem cells (SSCs) undergo self-renewal division to sustain spermatogenesis. Although it is possible to derive SSC cultures in most mouse strains, SSCs from a 129 background never proliferate under the same culture conditions, suggesting they have distinct self-renewal requirements. Here, we established long-term culture conditions for SSCs from mice of the 129 background (129 mice). An analysis of 129 testes showed significant reduction of GDNF and CXCL12, whereas FGF2, INHBA and INHBB were higher than in testes of C57BL/6 mice. An analysis of undifferentiated spermatogonia in 129 mice showed higher expression of Chrna4, which encodes an acetylcholine (Ach) receptor component. By supplementing medium with INHBA and Ach, SSC cultures were derived from 129 mice. Following lentivirus transduction for marking donor cells, transplanted cells re-initiated spermatogenesis in infertile mouse testes and produced transgenic offspring. These results suggest that the requirements of SSC self-renewal in mice are diverse, which has important implications for understanding self-renewal mechanisms in various animal species.

Intercellular transfer of plasmid DNA between in vitro cultured HEK293 cells following transient transfection

Gene overexpression by transient transfection of in vitro cultured model cell lines with plasmid DNA is a commonly used method for studying molecular aspects of human biology and pathobiology. However, there is accumulating evidence suggesting that human cells may actively secrete fragments of DNA and the implications of this phenomenon for in vitro cultured cells transiently transfected with foreign nucleic acids has been overlooked. Therefore, in the current study we investigated whether a cell-to-cell transmission of acquired plasmid DNA takes place in a commonly used human cell line model.We transiently transfected HEK293 cells with EGFP encoding plasmids to serve as donor cells and either co-cultured these with stably mCherry expressing recipient cells in different set-ups or transferred their culture medium to the recipient cells. We found that recipient cells produced EGFP after being co-cultured with donor cells but not when they were exposed to their culture medium. The employment of different co-culture set-ups excluded that the observed effect stemmed from technical artefacts and provided evidence that an intercellular plasmid transfer takes place requiring physical proximity between living cells. This phenomenon could represent a significant biological artefact for certain studies such as those addressing protein transmissions in prion diseases.

Hemangiosarcoma Cells Promote Conserved Host-Derived Hematopoietic Expansion.

Hemangiosarcoma and angiosarcoma are soft-tissue sarcomas of blood vessel-forming cells in dogs and humans, respectively. These vasoformative sarcomas are aggressive and highly metastatic, with disorganized, irregular blood-filled vascular spaces. Our objective was to define molecular programs which support the niche that enables progression of canine hemangiosarcoma and human angiosarcoma. Dog-in-mouse hemangiosarcoma xenografts recapitulated the vasoformative and highly angiogenic morphology and molecular characteristics of primary tumors. Blood vessels in the tumors were complex and disorganized, and they were lined by both donor and host cells. In a series of xenografts, we observed that the transplanted hemangiosarcoma cells created exuberant myeloid hyperplasia and gave rise to lymphoproliferative tumors of mouse origin. Our functional analyses indicate that hemangiosarcoma cells generate a microenvironment that supports expansion and differentiation of hematopoietic progenitor populations. Furthermore, gene expression profiling data revealed hemangiosarcoma cells expressed a repertoire of hematopoietic cytokines capable of regulating the surrounding stromal cells. We conclude that canine hemangiosarcomas, and possibly human angiosarcomas, maintain molecular properties that provide hematopoietic support and facilitate stromal reactions, suggesting their potential involvement in promoting the growth of hematopoietic tumors.

Donor Muse Cell Treatment Without HLA-Matching Tests and Immunosuppressant Treatment.

The strength of stem cell therapy is the regeneration of tissues by synergistic pleiotropic effects. Among many stem cell types, mesenchymal stem cells (MSCs) that are comprised of heterogenous population are widely used for clinical applications with the expectation of pleiotropic bystander effects. Muse cells are pluripotent-like/macrophage-like stem cells distributed in the bone marrow, peripheral blood, and organ connective tissues as cells positive for the pluripotent surface marker stage-specific-embryonic antigen -3. Muse cells comprise ~1% to several percent of MSCs. While Muse cells and MSCs share several characteristics, such as mesenchymal surface marker expression and their bystander effects, Muse cells exhibit unique characteristics not observed in MSCs. These unique characteristics of Muse cells include selective homing to damaged tissue after intravenous injection rather than being trapped in the lung like MSCs, replacement of a wide range of damaged/apoptotic cells by differentiation through phagocytosis, and long-lasting immunotolerance for donor cell use. In this review, we focus on the basic properties of Muse cells clarified through preclinical studies and clinical trials conducted by intravenous injection of donor-Muse cells without HLA-matching tests or immunosuppressant treatment. MSCs are considered to differentiate into osteogenic, chondrogenic, and adipogenic cells, whereas the range of their differentiation has long been debated. Muse cells may provide clues to the wide-ranging differentiation potential of MSCs that are observed with low frequency. Furthermore, the utilization of Muse cells may provide a novel strategy for clinical treatment.

Application of exosomes in oral regenerative medicine

In recent years, exosomes had been recognized as a potential cell-free therapeutic tool in the field of regenerative medicine due to their easy accessibility, low immunogenicity, and good therapeutic effect. As paracrine products of cells, exosomes not only have the functions of their donor cells but also involve fewer ethical disputes. They are more stable than traditional stem cell therapy, and easy to store, transport and sterilize, which are gradually applied in the field of oral regenerative medicine. This article provides a review of the general properties of exosomes and their application in the field of oral regeneration, with a view to exploring new pathways for functional regeneration of the stomatognathic system.

Sex-dependent niche responses modulate steady-state and regenerative hematopoiesis

Hematopoietic stem cells (HSCs) adapt to organismal blood production needs by balancing self-renewal and differentiation, adjusting to physiological demands and external stimuli. While sex differences have been implicated in differential hematopoietic function in males vs. females, the mediators responsible for these effects require further study. Here, we characterize hematopoiesis at steady state and during regeneration following hematopoietic stem cell transplantation (HST). RNA sequencing of lineage(-) bone marrow cells from C57/Bl6 mice revealed a broad transcriptional similarity between the sexes. However, we identified distinct sex differences in key biological pathways, with female cells showing reduced expression of signatures involved in inflammation and an enrichment of genes related to glycolysis, hypoxia, and cell cycle regulation, suggesting a more quiescent and less inflammatory profile compared to male cells. To determine the functional impacts of the observed transcriptomic differences, we performed sex-matched and mismatched transplantation studies of lineage(-) donor cells. During short-term 56-day HST recovery we found a male donor cell proliferative advantage, coinciding with elevated serum TNF-α, and a male recipient engraftment advantage, coinciding with increased serum CXCL12. Together, we show that sex-specific cell responses, marked by differing expression of pathways regulating metabolism, hypoxia, and inflammation, shapes normal and regenerative hematopoiesis, with implications for the clinical understanding of hematopoietic function.

Generation of a human iPSC cell line (MUSIi017-A) from a donor with O negative blood type

The Rh-negative type O blood group (O Rh-) is considered a universal donor for emergency blood transfusions. Due to the constant shortage of this rare blood group, the production of blood cells from iPSCs derived from the O Rh- donor could potentially serve as a limitless blood source for transfusions. In this report, we establish a MUSIi017-A iPSC line from peripheral blood mononuclear cells of a healthy donor with the O Rh- blood group. The established iPSC line exhibited a normal karyotype, showed identical STR compared to donor peripheral blood mononuclear cells, and could differentiate to all three germ layers.

A high-density microfluidic bioreactor for the automated manufacturing of CAR T cells.

The manufacturing of autologous chimaeric antigen receptor (CAR) T cells largely relies either on fed-batch and manual processes that often lack environmental monitoring and control or on bioreactors that cannot be easily scaled out to meet patient demands. Here we show that human primary T cells can be activated, transduced and expanded to high densities in a 2 ml automated closed-system microfluidic bioreactor to produce viable anti-CD19 CAR T cells (specifically, more than 60 million CAR T cells from donor cells derived from patients with lymphoma and more than 200 million CAR T cells from healthy donors). The in vitro secretion of cytokines, the short-term cytotoxic activity and the long-term persistence and proliferation of the cell products, as well as their in vivo anti-leukaemic activity, were comparable to those of T cells produced in a gas-permeable well. The manufacturing-process intensification enabled by the miniaturized perfusable bioreactor may facilitate the analysis of the growth and metabolic states of CAR T cells during ex vivo culture, the high-throughput optimization of cell-manufacturing processes and the scale out of cell-therapy manufacturing.

Ephrin Forward Signaling Controls Interspecies Cell Competition in Pluripotent Stem Cells.

In the animal kingdom, evolutionarily conserved mechanisms known as cell competition eliminate unfit cells during development. Interestingly, cell competition also leads to apoptosis of donor cells upon direct contact with host cells from a different species during interspecies chimera formation. The mechanisms underlying how host animal cells recognize and transmit cell death signals to adjacent xenogeneic human cells remain incompletely understood. In this study, we developed an interspecies cell contact reporter system to dissect the mechanisms underlying competitive interactions between mouse and human pluripotent stem cells (PSCs). Through single-cell RNA-seq analyses, we discovered that Ephrin A ligands in mouse cells play a crucial role in signaling cell death to adjacent human cells that express EPHA receptors during interspecies PSC co-culture. We also demonstrated that blocking the Ephrin A-EPHA receptor interaction pharmacologically, and inhibiting Ephrin forward signaling genetically in the mouse cells, enhances the survival of human PSCs and promotes chimera formation both in vitro and in vivo . Our findings elucidate key mechanisms of interspecies PSC competition during early embryogenesis and open new avenues for generating humanized tissues or organs in animals, potentially revolutionizing regenerative medicine.

Adenovirus- and cytomegalovirus-specific adoptive T-cell therapy in the context of hematologic cell transplant or HIV infection - A single-center experience.

Reactivation of viral infections, in particular cytomegalovirus (CMV) and adenovirus (ADV), cause morbidity and non-relapse-mortality in states of immune deficiency, especially after allogeneic hematopoietic cell transplantation (allo-HCT). Against the background of few available pharmacologic antiviral agents, limited by toxicities and resistance, adoptive transfer of virus-specific T-cells (VST) is a promising therapeutic approach. We conducted a single-center retrospective analysis of adult patients treated with ADV- or CMV-specific T-cells in 2012-2022. Information was retrieved by review of electronic health records. Primary outcome was a response to VST by decreasing viral load or clinical improvement. Secondary outcomes included overall survival and safety of VST infusion, in particular association with graft-versus-host disease (GVHD). Ten patients were included, of whom four were treated for ADV, five for CMV, and one for ADV-CMV-coinfection. Cells were derived from stem cell donors (6/10) or third-party donors (4/10). Response criteria were met by six of 10 patients (4/4 ADV, 2/5 CMV, and 0/1 ADV-CMV). Overall survival was 40%. No infusion related adverse events were documented. Aggravation of GVHD after adoptive immunotherapy was observed in two cases, however in temporal association with a conventional donor lymphocyte infusion and a stem cell boost, respectively. In this cohort, CMV- and ADV-specific T-cell therapy appear to be safe and effective. We describe the first reported case of virus-specific T-cell therapy for CMV reactivation not associated with transplantation but with advanced HIV infection. This encourages further evaluation of adoptive immunotherapy beyond the context of allo-HCT.

Dynamics of virological and immunological markers of HIV persistence after allogeneic haematopoietic stem-cell transplantation in the IciStem cohort: a prospective observational cohort study

Allogeneic haematopoietic stem-cell transplantation (allo-HSCT) markedly reduces HIV reservoirs, but the mechanisms by which this occurs are only partly understood. In this study, we aimed to describe the dynamics of virological and immunological markers of HIV persistence after allo-HSCT. In this prospective observational cohort study, we analysed the viral reservoir and serological dynamics in IciStem cohort participants with HIV who had undergone allo-HSCT and were receiving antiretroviral therapy, ten of whom had received cells from donors with the CCR5Δ32 mutation. Participants from Belgium, Canada, Germany, Italy, the Netherlands, Spain, Switzerland, and the UK were included in the cohort both prospectively and retrospectively between June 1, 2014 and April 30, 2019. In the first 6 months after allo-HSCT, participants had monthly assessments, with annual assessments thereafter, with the protocol tailored to accommodate for the individual health status of each participant. HIV reservoirs were measured in blood and tissues and HIV-specific antibodies were measured in plasma. We used the Wilcoxon signed-rank test to compare data collected before and after allo-HSCT in participants for whom longitudinal data were available. When the paired test was not possible, we used the Mann-Whitney U test. We developed a mathematical model to study the factors influencing HIV reservoir reduction in people with HIV after allo-HSCT. We included 30 people with HIV with haematological malignancies who received a transplant between Sept 1, 2009 and April 30, 2019 and were enrolled within the IciStem cohort and included in this analysis. HIV reservoirs in peripheral blood were reduced immediately after full donor chimerism was achieved, generally accompanied by undetectable HIV-DNA in bone marrow, ileum, lymph nodes, and cerebrospinal fluid, regardless of donor CCR5 genotype. HIV-specific antibody levels and functionality values declined more slowly than direct HIV reservoir values, decaying significantly only months after full donor chimerism. Mathematical modelling suggests that allogeneic immunity mediated by donor cells is the main viral reservoir depletion mechanism after massive reservoir reduction during conditioning chemotherapy before allo-HSCT (half-life of latently infected replication-competent cells decreased from 44 months to 1·5 months). Our work provides, for the first time, data on the effects of allo-HSCT in the context of HIV infection. Additionally, we raise the question of which marker can serve as the last reporter of the residual viraemia, postulating that the absence of T-cell immune responses might be a more reliable marker than antibody decline after allo-HSCT. amfAR (American Foundation for AIDS Research; ARCHE Program), National Institutes of Health, National Institute of Allergy and Infectious Diseases, and Dutch Aidsfonds.

Proteomic Analysis of Butyrate-Resistant Colorectal Cancer-Derived Exosomes Reveals Potential Resistance to Anti-Cancer Drugs.

Butyrate-resistant (BR) cells play an important role in acquiring chemoresistance in colorectal cancer (CRC). Our previous study demonstrated that BR CRC cells showed cross-resistance to chemotherapy drugs, including 5-fluorouracil and oxaliplatin, in both monolayer and spheroid cultures. The mechanisms underlying drug resistance were also elucidated. However, the link between parental (PT) and BR cells remains unclear. Extracellular vesicles (EVs) are key cell-cell communications that transport various molecules, including DNA, RNA, and proteins, between the donor and target cells. EVs contribute to drug resistance in cancers, such as melanoma and lung cancer. Recently, we focused on the correlation of proteomic profiles of EVs from different cell types. In this study, we analyzed the proteomic profiles of EVs derived from PT and BR cells to investigate the mechanisms underlying the butyrate- and chemo-resistant phenotypes. EVs were isolated from PT and BR cells using ultracentrifugation. The characteristics of the EVs were evaluated using western blot and transmission electron microscopy. The EV proteomic data were further analyzed using liquid chromatography-mass spectrometry. We identified a unique protein expressed in BR cells related to the chemoresistant phenotype. Functional enrichment analysis showed that BR cells had higher protein catalytic activity, binding, and transcription activity. The STITCH database showed a greater correlation between protein-drug interactions in BR cells than in PT cells. Moreover, our findings support the hypothesis that EVs promote tumor progression and metastasis and affect the tumor microenvironment. Proteomic analysis of EVs from BR CRC cells reveals insights into drug resistance mechanisms, including protein-mediated carcinogenesis and reduced drug uptake, offering potential strategies to overcome resistance in clinical practice.

Interim analysis of a phase I study using cryopreserved non-genetically modified allogeneic natural killer cells with enhanced cytotoxicity (SNK02) in patients with advanced solid tumors without lymphodepletion.

e14515 Background: Natural killer (NK) cells play a key role as the main effector cells toward cancer in innate immunity. A leading approach to boost NK cell-mediated anti-tumor activity is via the adoptive transfer of ex vivo activated NK cells. Current allogeneic donor-derived products require lymphodepletion to prevent immunologic rejection of donor cells by the recipient and ensure adequate cell delivery of the product cells to the target. However, lymphodepletion can negatively impact combination therapies where a robust T cell response is desired. SNK02 is a first-in-kind, cryopreserved allogeneic non-genetically modified NK cell product with significant anti-tumor cytotoxicity and over 90% expression of CD16, NKG2D, NKp46, and DNAM-1, that can be consistently produced on a large commercial scale. We hypothesized that higher doses of SNK02 (to overcome autodigestion) could be delivered frequently without the need for lymphodepletion and that it might demonstrate activity against solid tumors that have failed multiple prior standard-of-care treatment options. Methods: In this Phase 1 dose escalation study (NCT05990920), SNK02 was administered intravenously (IV) weekly for 8 consecutive weeks in patients with advanced solid tumors. The starting dose was 6 x 109 SNK02 cells. The primary endpoint was safety based on adverse events (AEs), vitals, laboratory tests, and physical exams. Results: As of Feb 1, 2023, 5 patients with advanced refractory solid tumors have been enrolled. Median age was 64 (range 44 – 71) and 3 were male. The subtypes were 1 leiomyosarcoma, 1 angiosarcoma, 1 endometrial adenocarcinoma, 1 undifferentiated pleomorphic sarcoma, and 1 colorectal adenocarcinoma. Four of five patients completed 8 cycles of SNK02. There was 1 death on study, which was deemed unrelated to the investigational product (IP). Out of the 36 doses administered through Cycle 8, there were 17 Grade 1, 3 Grade 2, and 1 Grade 3 adverse AEs related to IP. The Grade 3 AE of increased fatigue resolved after 1 day with no intervention required. Antibodies appeared to develop around cycle 5 and appeared to correlate with AEs. The best objective response of SD was demonstrated in 100% of patients that completed the 8 cycles. Conclusions: SNK02 was well tolerated as a monotherapy and appears to have some clinical activity against pretreated solid tumors despite the lack of lymphodepletion. SNK02 will continue to be studied as a monotherapy and in potential combination treatment regimens with monoclonal antibodies and immune checkpoint inhibitors. Clinical trial information: NCT05990920 .

A phase 1 trial of TSC-100 and TSC-101, engineered T cell therapies that target minor histocompatibility antigens to eliminate residual disease after hematopoietic cell transplantation.

TPS2678 Background: Engineered T cell therapies such as CAR-T cell therapies have transformed the treatment of B-cell but not non-B cell hematologic malignancies. Allogeneic hematopoietic cell transplantation (HCT) remains the best curative option for hematologic malignancies but ~40% of patients relapse post-HCT with up to 90% mortality due to residual disease post-HCT. A potential solution is targeting minor histocompatibility antigens (MiHAs) that are homogenously expressed on all hematopoietic cells and are genetically mismatched between donors and patients undergoing HCT. These mismatches enable engineered T cells to selectively eliminate residual patient hematopoietic cells, normal or malignant, leaving donor cells untouched. TScan has developed allogeneic donor derived T-cell products TSC-100 and TSC-101, targeting MiHAs HA-1 and HA-2 respectively, both presented on HLA-A*02:01. By choosing HCT patients who are HLA-A*02:01 positive (&gt;98% of whom are either HA-1 or HA-2 positive) and donors who are either HLA-A*02:01 or MiHA negative, TSC-100 or TSC-101 can potentially eliminate all residual patient-derived hematopoietic cells after HCT, to prevent disease relapse. Methods: Study NCT05473910 is a multi-center, multi-arm, non-randomized controlled Phase 1 umbrella study evaluating the feasibility, safety and preliminary efficacy of TSC-100 and TSC-101. Inclusion criteria include adults with AML, MDS or ALL eligible for reduced intensity conditioning-based haploidentical donor transplantation from HLA or MiHA mismatched donors. HLA-A*02:01-positive patients undergo HA-1/ HA-2 testing and are assigned to either TSC-100 or TSC-101 treatment arms in addition to HCT. HLA-A*02:01-negative patients in the control arm receive HCT alone. Upon count recovery after HCT, patients in treatment arms receive either TSC-100 or TSC-101, administered as single or two doses. Primary endpoints include adverse event profiles and dose limiting toxicities. Secondary endpoints include relapse rates, disease-free survival and overall survival. Exploratory endpoints include surrogates of efficacy such as donor chimerism rates and kinetics and minimal residual disease (MRD) rates. Donor chimerism is measured by standard STR-based and novel high-sensitivity NGS-based assays to quantify residual patient-derived hematopoietic cells. MRD is measured before and after HCT using flow cytometry and NGS. Together, these assays measure elimination of residual patient hematopoietic cells, malignant or normal, and could provide early evidence of biological activity. Clinical trial information: NCT05473910 .