Surface Marker Expression Research Articles

Comparative genomics identified TLR-dependent fine tuning of the dendritic cell immune response by melatonin

Abstract Melatonin, a neuro hormone, has been shown to activate human monocytes and induce their cytotoxic properties in addition to the production of IL-1, IL-6, and TNF-α. The molecular mechanisms involved in melatonin and dendritic cell interactions are largely unknown. In this study, we performed a comprehensive RNA sequencing (RNA-seq)-based analysis of monocyte-derived human dendritic cells across different melatonin stimulations. We profiled gene expression changes among naïve DCs along with DCs generated with melatonin (MDCs) and DCs matured with melatonin (DCMs). We found that melatonin significantly promoted the morphological maturation of MDCs and increased the expression of DC-related surface markers. Furthermore, MDCs increased the general immune response by promoting the secretion of IL-12, IL-6 and IFN-γ cytokines and enhancing the proliferation of TH cells, while DCM did not. Genome-wide comparative transcriptomic profiling showed that the expression of 7417 genes was significantly upregulated, and 3325 genes were significantly downregulated in MDCs. We observed the spatiotemporal activity of TLR 2-, 4-, 6- and 8-specific genes in MDCs. Interestingly, we found that the expression of TLR 10-specific signaling genes was significantly higher in DCMs. Further in vitro validation showed that along with TLRs, the upregulation of IRAK, GRB2, CREB and TNFRSF was significantly associated with MDCs. Overall, we found that during the differentiation of dendritic cells, the presence of melatonin generates a unique population of dendritic cells with activated TLR4 signaling. DCs generated through this unique culture process may act as good candidates for immunomodulation during cancer and inflammation. Supported by grants fromDST-SERB, GOI (CRG/2019/001296)

A rapid and high-throughput T cell immunophenotyping assay for cellular therapy bioprocess using the Cellaca PLX image cytometer

Abstract Cellular therapies such as chimeric antigen receptor (CAR) T or NK cells undergo phenotypic characterization during discovery and development of novel therapies, biomanufacturing, and upstream patient cell processing for clinical use. Samples are routinely analyzed via flow cytometry for T cell, NK cell, B cell, and monocyte surface marker expression. Image cytometry systems perform cell-based assays that can be used as a convenient alternative to flow cytometry. Recently, a new high-throughput image cytometer, the Cellaca PLX system (Nexcelom, Lawrence, MA) was developed for immunophenotyping, transfection/transduction efficiency, and cell health assays. This new instrument can assess several critical quality attributes (CQAs) such as cell identity, viability, and other relevant biological functions recommended by the International Organization for Standardization using the ISO Cell Characterization that focuses on cellular therapeutic products. Here we demonstrate a rapid and high-throughput immunophenotyping and viability detection in peripheral blood mononuclear cells (PBMCs) using the Cellaca PLX. PBMCs underwent red blood cell (RBC) lysis and CD3 enrichment, were stained with Hoechst/CD3/CD4/CD8 or Hoechst/CD3/CD8/RubyDead surface marker kits and measured on the Cellaca PLX and three different flow cytometers for comparison. Results showed highly comparable cell populations between the flow cytometers and the Cellaca PLX suggesting that the image cytometer may provide a rapid and convenient alternative method for immunophenotyping. The proposed method can streamline workflows from sample staining to data analysis, quickly moving precious patient samples into downstream processes.

Esculetin releases maturation arrest and induces terminal differentiation in leukemic blast cells by altering the Wnt signaling axes

BackgroundThe “Differentiation therapy” has been emerging as a promising and more effective strategy against acute leukemia relapses.ObjectiveIn extension to the revolutionising therapeutic outcomes of All Trans Retinoic Acid (ATRA) to induce terminal differentiation of Acute Promyelocytic Leukemic (APL) blast cells, we decipher the potential effect of a natural compound “Esculetin” to serve as a differentiating agent in Acute Myeloid Leukemia (AML). Underlaying role of Wnt signaling pathways in esculetin mediated blast cell differentiation was also evaluated.MethodsHuman acute myeloid leukemic cells (Kasumi-1) with t(8;21/AML-ETO) translocation were used as a model system. Growth inhibitory and cytotoxic activity of esculetin were analysed using growth kinetics and MTT assay. Morphological alterations, cell scatter characteristics, NBT reduction assay and cell surface marker expression patterns were analysed to detect terminally differentiated phenotypes. We employed RT2profiler PCR array system for the analysis of transcriptome profile of Wnt signaling components. Calcium inhibitors (TMB8 and Amlodipine) and Transforming growth factor beta (TGF-β) were used to modulate the Wnt signaling axes.ResultsWe illustrate cytotoxic as well as blast cell differentiation potential of esculetin on Kasumi-1 cells. Morphological alterations akin to neutrophilic differentiation as well as the corresponding acquisition of myeloid lineage markers indicate terminal differentiation potential of esculetin in leukemic blast cells. Exposure to esculetin also resulted in downregulation of canonical Wnt axis while upto ~ 21 fold upregulation of non-canonical axis associated genes.ConclusionsOur study highlights the importance of selective use of calcium pools as well as “axis shift” of the canonical to non-canonical Wnt signaling upon esculetin treatment which might abrogate the inherent proliferation to release maturation arrest and induce the differentiation in leukemic blast cells. The current findings provide further therapeutic interventions to consider esculetin as a potent differentiating agent to counteract AML relapses.

Suppression of IGRP-specific CD8 T cells following induction of tolerance to a Hybrid Insulin Peptide CD4 neoepitope

Abstract An autoimmune-mediated death of insulin-producing beta cells, orchestrated by effector CD4 and CD8 T cells that recognize islet antigens, results in Type 1 Diabetes. A dominant CD4 islet autoantigen in the NOD mouse model of autoimmune diabetes is a neoepitope termed the 2.5 Hybrid Insulin Peptide (2.5HIP). By delivering the 2.5HIP as an antigen-specific immunotherapy on tolerogenic PLG-nanoparticles, islet grafts in diabetic NOD mice survived longer and cytokine production in autoreactive CD4 and CD8 T cells was suppressed, including the well-studied IGRP tetramer+ (tet+) CD8 T cells. Using both diabetic transplant recipients and prediabetic NOD mice treated with 2.5HIP nanoparticles, we examined mechanisms of peripheral tolerance induction to a dominant CD4 neoepitope and the impact on the function of IGRP CD8 T cells. Following induction of tolerance to the 2.5HIP, there was an increase in dysfunctional surface marker expression (PD1+ TIM3+) on effector 2.5HIP tet+ CD4 T cells in the spleen of treated mice. Along with a decrease in effector function, we observed an increase in the fraction of both Treg and Tr1 2.5HIP tet+ T cells expressing IL10 in the islets, spleen, and draining lymph nodes of tolerized mice. Concurrently, IGRP tet+ CD8 T cells accumulated in the draining lymph nodes and were less able to traffic and infiltrate islets. Of the IGRP tet+ cells that entered islets, there were fewer cytolytic CX 3CR1 +effector cells in tolerized mice. The robust functional increase in both Treg and Tr1 2.5HIP tet+ T cells may provide a potential mechanism for the accumulation of IGRP tet+ CD8 T cells in the draining lymph node and explain their inefficient trafficking into, and function within, islets following tolerance induction. NIH - T32 5T32DK120520-03, R01 2R01DK081166-11) JDRF 2-SRA-2020-907-S-B

Biological scaffold implants in a murine volumetric muscle loss trauma model cause time dependent CD62L and CD101 upregulation on “regulatory like” eosinophils.

Abstract Introduction: Previously, we reported a strong increase in the recruitment of eosinophils at injured muscle when treated with a biologic scaffold implant. As such, we sought to characterize the surface marker expression of these eosinophils to understand their role at the site of injury. Method: Volumetric muscle loss (VML) model was performed on C57BL/6 mice and was subsequently treated with a biologic scaffold (decellularized extracellular matrix). After 7 and 21 days, post-injury, implanted material along with injured tissue was dissected and converted to single cell suspension for flow cytometry. Results: Compared to uninjured mice, at both 7 and 21 days time point, mice that received biological scaffold featured significantly increased presence of eosinophils at the site of injury. These eosinophils had a ring-shaped nucleus which has been previously associated with regulatory eosinophils. Eosinophils at the site of injury showed time dependent upregulation of CD101 (Mean fold change from uninjured muscle after 7 days post implant was 2.73 and the same was 9.90 after 21 days, (p<0.0001)), and CD62L (Mean fold change from uninjured muscle after 7 days post implant was 3.65 and the same was 11.64 after 21 days(p<0.0001)) expression. Interestingly, the same pattern was not observed with blood eosinophils except that the blood eosinophils at 3-week timepoint were featuring a significant increase in CD62L expression compared with 1 week time point, suggesting potential return of homeostasis in circulatory compartment. Conclusion: Here, we describe time-dependent transformation in eosinophil phenotype in response to biologic scaffold implantation, including upregulation of adhesion molecule CD62L and a regulatory marker CD101.

IMMUNOPHENOTYPE OF MESENCHYMAL STEM CELLS DERIVED FROM EPICARDIAL AND PERIVASCULAR ADIPOSE TISSUE IN PATIENTS WITH CARDIOVASCULAR DISEASES

Aim: to evaluate the immunophenotype of adipose tissue stem cells isolated from epicardial and perivascular fat depots in patients with coronary heart disease and acquired heart defects. Results: In cell culture obtained from epicardial adipose tissue (EAT) and perivascular adipose tissue (PVAT) (2nd passage) in patients with both coronary heart disease and acquired heart defects, a high (over 90%) expression of membrane proteins characteristic of stem cells. In addition to the main population, with both in the EAT culture and in the PVAT, there were 2 minor ones: 1 – CD90-, CD105+, CD34-/+, CD73+, CD45- is presumably endothelial population, 2 – CD90+, CD105-, CD34-, CD73-, CD45- is the smallest population. Conclusion: In the early stages of cultivation, cells of the stromal vascular fraction isolated from epicardial and perivascular adipose tissue express surface markers characteristic of adipose tissue stem cells.

Selection of Cell Populations with High or Low Surface Marker Expression Using Magnetic Sorting.

Magnetic cell sorting technology stands out because of its speed, simplicity, and ability to process large cell numbers. However, it also suffers from a number of drawbacks, in particular low discrimination power, which results in all-or-none selection outcomes limited to a bulk separation of cell populations into positive and negative fractions, as well as the modest purity of the selected cells and the inability to select subpopulations of cells with high expression of a surface marker. In the present study, we developed a simple solution to this problem and confirmed the effectiveness of this approach by multiple experiments with the magnetic selection of transduced cell populations. Murine NIH 3T3 cells were transduced with the bicistronic retroviral vector constructs co-expressing fluorescent reporter proteins EGFP (enhanced green fluorescent protein) or DsRed-Express 2 and LNGFR (low-affinity nerve growth factor receptor) as surface selection markers. The effects of the magnetic selection of transduced cells with anti-LNGFR Micro Bead (MB) doses ranging from 0.5 to 80 µL have been assessed. Low doses of MBs favored the depletion of weakly positive cells from the population, resulting in the higher expression levels of EGFP or DsRed-Express2 reporters in the selected cell fractions. Low MB doses also contributed to the increased purity of the selected population, even for samples with a low initial percentage of positive cells. At the same time, high MB doses resulted in the increased yield and a more faithful representation of the original expression profiles following selection. We further demonstrate that for populations with fairly narrow distribution of expression levels, it is possible to achieve separation into high- and low-expressing subsets using the two-stage selection scheme based on the sequential use of low and high doses of MBs. For populations with broad expression distribution, a one-stage selection with low or high doses of MBs is sufficient for a clear separation of low- and high-expressing subsets in the column-retained and flow-through fractions, respectively. This study substantially extends the potential of magnetic cell sorting, and may open new possibilities in a number of biomedical applications.

T follicular helper cells and T follicular regulatory cells in autoimmune diseases.

T follicular helper (Tfh) cells are heterogeneous and mainly characterized by expressing surface markers CXCR5, ICOS, and PD-1; cytokine IL-21; and transcription factor Bcl6. They are crucial for B-cell differentiation into long-lived plasma cells and high-affinity antibody production. T follicular regulatory (Tfr) cells were described to express markers of conventional T regulatory (Treg) cells and Tfh cells and were able to suppress Tfh-cell and B-cell responses. Evidence has revealed that the dysregulation of Tfh and Tfr cells is positively associated with the pathogenic processes of autoimmune diseases. Herein, we briefly introduce the phenotype, differentiation, and function of Tfh and Tfr cells, and review their potential roles in autoimmune diseases. In addition, we discuss perspectives to develop novel therapies targeting Tfh/Tfr balance.

Human fetal cartilage-derived chondrocytes and chondroprogenitors display a greater commitment to chondrogenesis than adult cartilage resident cells.

Obtaining regeneration-competent cells and generating high-quality neocartilage are still challenges in articular cartilage tissue engineering. Although chondroprogenitor cells are a resident subpopulation of native cartilage and possess a high capacity for proliferation and cartilage formation, their potential for regenerative medicine has not been adequately explored. Fetal cartilage, another potential source with greater cellularity and a higher cell-matrix ratio than adult tissue, has been evaluated for sourcing cells to treat articular disorders. This study aimed to compare cartilage resident cells, namely chondrocytes, fibronectin adhesion assay-derived chondroprogenitors (FAA-CPCs) and migratory chondroprogenitors (MCPs) isolated from fetal and adult cartilage, to evaluate differences in their biological properties and their potential for cartilage repair. Following informed consent, three human fetal and three adult osteoarthritic knee joints were used to harvest the cartilage samples, from which the three cell types a) chondrocytes, b) FAA-CPCs, and MCPs were isolated. Assessment parameters consisted of flow cytometry analysis for percentage expression of cell surface markers, population doubling time and cell cycle analyses, qRT-PCR for markers of chondrogenesis and hypertrophy, trilineage differentiation potential and biochemical analysis of differentiated chondrogenic pellets for total GAG/DNA content. Compared to their adult counterparts, fetal cartilage-derived cells displayed significantly lower CD106 and higher levels of CD146 expression, indicative of their superior chondrogenic capacity. Moreover, all fetal groups demonstrated significantly higher levels of GAG/DNA ratio with enhanced uptake of collagen type 2 and GAG stains on histology. It was also noted that fetal FAA CPCs had a greater proliferative ability with significantly higher levels of the primary transcription factor SOX-9. Fetal chondrocytes and chondroprogenitors displayed a superior propensity for chondrogenesis when compared to their adult counterparts. To understand their therapeutic potential and provide an important solution to long-standing challenges in cartilage tissue engineering, focused research into its regenerative properties using in-vivo models is warranted.

Macrophages regulate gastrointestinal motility through complement component 1q.

Peristaltic movement of the intestine propels food down the length of the gastrointestinal tract to promote nutrient absorption. Interactions between intestinal macrophages and the enteric nervous system regulate gastrointestinal motility, yet we have an incomplete understanding of the molecular mediators of this crosstalk. Here, we identify complement component 1q (C1q) as a macrophage product that regulates gut motility. Macrophages were the predominant source of C1q in the mouse intestine and most extraintestinal tissues. Although C1q mediates the complement-mediated killing of bacteria in the bloodstream, we found that C1q was not essential for the immune defense of the intestine. Instead, C1q-expressing macrophages were located in the intestinal submucosal and myenteric plexuses where they were closely associated with enteric neurons and expressed surface markers characteristic of nerve-adjacent macrophages in other tissues. Mice with a macrophage-specific deletion of C1qa showed changes in enteric neuronal gene expression, increased neurogenic activity of peristalsis, and accelerated intestinal transit. Our findings identify C1q as a key regulator of gastrointestinal motility and provide enhanced insight into the crosstalk between macrophages and the enteric nervous system.

A Bayesian feature allocation model for identifying cell subpopulations using CyTOF data.

A Bayesian feature allocation model (FAM) is presented for identifying cell subpopulations based on multiple samples of cell surface or intracellular marker expression level data obtained by cytometry by time of flight (CyTOF). Cell subpopulations are characterized by differences in marker expression patterns, and cells are clustered into subpopulations based on their observed expression levels. A model-based method is used to construct cell clusters within each sample by modeling subpopulations as latent features, using a finite Indian buffet process. Non-ignorable missing data due to technical artifacts in mass cytometry instruments are accounted for by defining a static missingship mechanism. In contrast with conventional cell clustering methods, which cluster observed marker expression levels separately for each sample, the FAM-based method can be applied simultaneously to multiple samples, and also identify important cell subpopulations likely to be otherwise missed. The proposed FAM-based method is applied to jointly analyse three CyTOF datasets to study natural killer (NK) cells. Because the subpopulations identified by the FAM may define novel NK cell subsets, this statistical analysis may provide useful information about the biology of NK cells and their potential role in cancer immunotherapy which may lead, in turn, to development of improved NK cell therapies.

Comparison of methods for the isolation and culture of Migratory chondroprogenitors from Human articular cartilage

ABSTRACT Purpose Resident articular stem cells isolated using a migratory assay called Migratory Chondroprogenitors (MCPs) have emerged as a promising cellular therapeutic for the treatment of cartilage pathologies. In-vivo studies using MCPs report their superiority over bone-marrow mesenchymal stem cells and chondrocytes for treating chondral defects. However, there is no consensus on their isolation protocol. This study aimed to compare four reported isolation methods of MCPs and identify the optimal and feasible protocol for future translational work. Methods Human MCPs isolated from osteoarthritic cartilage (n = 3) were divided into four groups: a) MCP1: 8–15 mm cartilage explants, b) MCP2: 8–10 mm explants digested in 0.1% collagenase for 2 hrs. and cultured c) MCP3: 1 mm cartilage explants and d) MCP 4: 25 mm explants with a X tear, 7-day culture, and trypsinization to release migrated cells. The MCPs were subjected to the following analysis: growth kinetics, surface marker expression, mRNA gene expression for markers of chondrogenesis and hypertrophy, and trilineage differentiation. Results MCPs isolated via the four methods showed similar surface marker profiles, chondrogenic (SOX-9, ACAN, COL2A1) and hypertrophic (COL1, RUNX2) gene expression. The migration time for the MCP3 group was the longest. The MCP1, MCP2, and MCP4 groups produced MCPs with comparable cellular expansion feasibility. Conclusions MCPs can be preferably isolated by the any of the three above methods based on the investigator’s discretion. In the case of small cartilage samples similar to the MCP3 group, the isolation of MCP is plausible, keeping in mind the additional time required.

Donor variability of ovine bone marrow derived mesenchymal stem cell - implications for cell therapy

ABSTRACT It is assumed that all species, including sheep, demonstrate significant variation between individuals including the characteristics of their bone marrow-derived mesenchymal stem cells (BM-MSCs). These differences may account for limited success in pre-clinical animal studies and may also impact on treatment strategies that are used within regenerative medicine. This study investigates variations between ovine MSCs (oMSCs) isolated from 13 English Mule sheep donors by studying cell viability, expansion, the cells’ trilineage differentiation potential and the expression of cell surface markers. In addition to the primary objective, this article also compares various differentiation media used for the trilineage differentiation of oMSCs. In this study, a clear individual variation between the sheep donors regarding oMSCs characterization, tri-lineage differentiation potential and marker expression was effectively demonstrated. The results set out to systematically explore the ovine mesenchymal stem cell population derived from multiple donors. With this information, it is possible to start addressing the issues of personalized approaches to regenerative therapies.

Upregulation of the ZNF148/PTX3 axis promotes malignant transformation of dendritic cells in glioma stem-like cells microenvironment.

The recent development of dendritic cell (DC)-based immunotherapy has resulted in advances in glioblastoma multiforme (GBM) treatment. However, the cell fate of DCs in the GBM microenvironment, especially in microenvironments in which glioma stem cell (GSCs)-mediated remodeling has resulted in highly immunosuppressive conditions, has not yet been fully investigated. Observed the interaction between GSCs and primary cultured DCs in a dual-color tracing model, monoclonal and continuously passaged highly proliferative DCs, and named transformed DCs (t-DCs). The expression of DC-specific surface markers was analyzed using RT-PCR, chromosome karyotype, and flow cytometry. The expression of long pentraxin 3 (PTX3) and its transcription factor zinc finger protein 148 (ZNF148) in t-DCs was detected using qRT-PCR and western blot. CCK8 and transwell assays were conducted to assess the effect of ZNF148 and PTX3 on the proliferation, migration, and invasion of t-DCs. Bioinformatics analysis, dual-luciferase reporter assay, and chromatin immunoprecipitation (ChIP)-qPCR assay were used to explore the relation between ZNF148 and PTX3. Transformed DCs (t-DCs) still expressed DC-specific surface markers, namely, CD80 and CD11c, and immune-related costimulatory molecules, namely, CD80, CD86, CD40, and ICAM-1. However, the expression levels of these molecules in t-DCs decreased moderately compared to those in naive DCs. Stable overexpression of PTX3 further promoted the proliferation and migration of t-DCs in vitro, decreased the expression of costimulatory molecules, and increased the tumorigenicity of t-DCs in vivo. The transcription factor zinc finger protein 148 (ZNF148) was directly bound to the PTX3 promoter region and enhanced PTX3 expression. Downregulation of ZNF148 significantly decreased PTX3 expression and reduced the proliferation and migration of t-DCs. Overexpression of ZNF148 significantly increased PTX3 expression and promoted the proliferation and migration of t-DCs, achieving the same biological effects as PTX3 overexpression in t-DCs. Simultaneously, the downregulation of ZNF148 partially reversed the effect of PTX3 overexpression in t-DCs. The ZNF148/PTX3 axis played an important role in regulating the malignant transformation of DCs after cross-talk with GSCs, and this axis may serve as a new target for sensitizing GBM to DC-based immunotherapy.

Detection of humoral and cellular immune response to anti-SARS-CoV-2 BNT162b2 vaccine in breastfeeding women and naïve and previously infected individuals

This study explored humoral and cellular responses to anti-SARS-CoV-2 BNT162b2 mRNA vaccine in breastfeeding women and naïve and seropositive individuals in the first six months after vaccination.Sixty-one volunteers vaccinated with two doses of the BNT162b2 mRNA vaccine were enrolled in the study. In-house developed ELISA was used for the quantification of SARS-CoV-2 RBD-specific antibodies. Cell surface marker expression and intracellular IFN-γ analysis were carried out by flow cytometry. The concentrations of IFN-γ, IL-6 and TNF were determined by ELISA. A significant rise in anti-RBD IgG antibody levels was observed 14 days after the first vaccine dose (p < 0.0001) in serum and milk. The expression of CD28 on CD4+ T cells was significantly higher compared to baseline (p < 0.05). There was a significant increase (p ≤ 0.05) in B cell lymphocyte subset after revaccination, and increased percentage of CD80+ B cells. The expression of IFN-γ in peripheral blood lymphocytes, CD3+ T cells and serum was significantly increased (p < 0.05). No significant difference in immune response was observed between breastfeeding women and other study participants. The anti-SARS-CoV-2 BNT162b2 mRNA vaccine-induced measurable and durable immune response in breastfeeding women and in naïve and previously infected individuals.

Effects of human placenta cryopreservation on molecular characteristics of placental mesenchymal stromal cells.

Cryopreservation of placenta tissue for long-term storage provides the opportunity in the future to isolate mesenchymal stromal cells that could be used for cell therapy and regenerative medicine. Despite being widely used, the established cryopreservation protocols for freezing and thawing still raise concerns about their impact on molecular characteristics, such as epigenetic regulation. In our study, we compared the characteristics of human placental mesenchymal stromal cells (hPMSCs) isolated from fresh (native) and cryopreserved (cryo) placenta tissue. We assessed and compared the characteristics of native and cryo hPMSCs such as morphology, metabolic and differentiation potential, expression of cell surface markers, and transcriptome. No significant changes in immunophenotype and differentiation capacity between native and cryo cells were observed. Furthermore, we investigated the epigenetic changes and demonstrated that both native and cryo hPMSCs express only slight variations in the epigenetic profile, including miRNA levels, DNA methylation, and histone modifications. Nevertheless, transcriptome analysis defined the upregulation of early-senescence state-associated genes in hPMSCs after cryopreservation. We also evaluated the ability of hPMSCs to improve pregnancy outcomes in mouse models. Improved pregnancy outcomes in a mouse model confirmed that isolated placental cells both from native and cryo tissue have a positive effect on the restoration of the reproductive system. Still, the native hPMSCs possess better capacity (up to 66%) in comparison with cryo hPMSCs (up to 33%) to restore fertility in mice with premature ovarian failure. Our study demonstrates that placental tissue can be cryopreserved for long-term storage with the possibility to isolate mesenchymal stromal cells that retain characteristics suitable for therapeutic use.

Stemness targeting of colorectal cell lines mediated by BAMLET and 5-Flourouracil

PurposeStemness is the potential for self-renewal and repopulation causing the relapse, progression, and drug resistance of colorectal cancer. We investigated the effects of bovine alpha-lactalbumin made lethal to tumor cells and 5-Flourouracil consisting of bovine α-lactalbumin protein and oleic acid, on colorectal cancer cells on stemness. MethodsThe quantitative real-time polymerase chain reaction assessed the expression levels of stemness-related genes (c-myc, Lgr5, OCT4). Expression of stemness-related surface markers (CD44 and CD24) was also measured by the flow cytometry technique following the treatments. ResultsOur results indicated decreased expression levels of C-Myc, Lgr5, oct4 as the stemness-related genes (P < 0.0001), and reduced population of CD44+ as the stemness-related cell surface marker upon treatment with BAMLET and 5-Flourouracil. BAMLET inhibited the stemness more effectively than 5-Flourouracil (P < 0.0001). ConclusionBased on the result, inhibition of the Stemness related-genes (C-Myc, Lgr5, Oct4) and the surface markers (CD 24+ and CD44+) is a promising therapeutic approach using BAMLET.

Abstract 690: Modification of mRNA-encoded HPV16 antigens to include endolysosomal trafficking domains drives cross-presentation and results in superior in vivo and ex vivo antigen-specific responses

Abstract Many cancer immunotherapies require the strong activation of the T-cell mediated adaptive immune response to elicit their full anti-tumor potential. Antigen processing and presentation is a complex, multistep process that can be significantly enhanced via antigen modification, leading to better antigen-specific immune responses. Using mRNA, we can express exogenous antigens inside the cell and facilitate the subcellular localization of these antigens to enhance antigen processing and presentation. In this work, we introduced endolysosomal trafficking domains from CD1d molecules to drive subcellular localization of antigenic proteins to the late endosomes (LE) to enhance class I and class II antigen loading. CD1d are molecules that naturally traffic between the membrane and the late endosomes, where antigens are processed and loaded to both class II and class I molecules in a TAP-independent manner. We compared the immunogenicity of a novel endolysosomal trafficking domain, human CD1d, coupled to a chimeric HPV16 E6 and E7 (HPV16E6E7-hCD1d) antigen to antigen designs intended to be either a) secreted (Sec-HPV16E6E7), b) retained in the endoplasmic reticulum (ER) by an ER retention signal KDEL (HPV16E6E7-KDEL) or c) unmodified antigen sequence (HPV16E6E7). To ensure intracellular translation and expression, all antigens were encoded and delivered as mRNAs. The immunogenicity of each antigen design was assessed in HPV16 positive cervical intraepithelial neoplasia (CIN) donor derived PBMCs and healthy controls. Using confocal microscopy, we observed that the hCD1d trafficking domain directed the translated E6E7 protein into late endosomes, which was not observed for any of the other antigen designs. Importantly, antigen localization to late endosomes resulted in significantly improved immunogenicity in vitro as well as in vivo. We observed a consistent increase in numbers of activated antigen-specific T cells across multiple CIN donor PBMCs treated with HPV16E6E7-hCD1d compared to the other 3 designs, as measured by Interferon gamma secretion, surface marker expression, and T-cell proliferation. To assess the generalizability of this approach, we also compared immunogenicity in human donor PBMCs using the human cytomegalovirus antigen pp65, and observed similar results. Lastly, the immunogenicity of each antigen design was tested in vivo by intramuscular injection of nanoparticle formulated mRNAs in C56/Bl6 mice, and inclusion of the murine analogue (mCD1d) resulted in significantly increased generation of HPV16-specific T cell responses. Based on these findings, we are developing a novel mRNA-based cancer therapeutic that includes the addition of hCD1d trafficking domain in the HPV16-specific antigen component. Citation Format: Weiqun Liu, Daniel Fernandez, Colin J. McKinlay, Daniel O. Frimannsson, Meredith L. Leong, W. Martin Kast, Samuel Deutsch, Ole Audun W. Haabeth. Modification of mRNA-encoded HPV16 antigens to include endolysosomal trafficking domains drives cross-presentation and results in superior in vivo and ex vivo antigen-specific responses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 690.

Abstract 4040: Asciminib activates erythroid differentiation in K562 cell line

Abstract Background: Asciminib an allosteric tyrosine kinase inhibitor (TKI) was recently approved by the FDA for managing Philadelphia positive chronic myeloid leukemia (CML) patients in chronic phase who had failed to respond to previous TKIs. In this study, we used human erythroleukemic K562 cell line to investigate the role of asciminib as an inducer of erythroid differentiation. Additionally, imatinib, which has previously been reported as a potential inducer of erythroid differentiation, was also tested on these cells, both independently as well as in combination, in order to investigate the degree of erythroid differentiation in a K562 cell line. Methodology: In this study, we investigated the effect of asciminib (5-20nM) with and without imatinib (50-200nM) in differentiating the erythroleukemic cell line K562 towards erythroid lineage. K562 cells were cultured over a 12-day period in basic (IMDM) media and an EPO-based differentiation media to select optimal medium conditions. In addition, an in-vitro drug cytotoxicity experiment (XTT) was used to determine the preliminary toxicity of asciminib with IMDM media and EPO-based differentiation media CD235a and CD71 surface marker expressions were analyzed by flow cytometry at all time-points to determine the degree of differentiation achieved by each of the conditions Moreover, to analyze and identify hemoglobin producing cells ensuing differentiation, benzidine staining was performed at indicated time points. Results: Our results suggest that asciminib, imatinib or a combination of both drugs in EPO-based differentiation media results in efficient erythroid differentiation with high levels of GPA expression (approx. 90%) and significant upregulation of globin genes (p value = 0.0001). These results were further confirmed by benzidine staining, where drug addition and dose escalation significantly increased benzidine-positive cells. Our results also demonstrated that asciminib was able to achieve maximum differentiation at a much earlier time point as compared to imatinib. Moreover, asciminib, when combined with another TKI such as imatinib, can also aid in lowering the drug concentrations being used, hence resulting in lessening the toxicity of the drug when used alone required at high doses. Conclusion: The results from this study highlighted the novel role of asciminib in erythroid differentiation using an in-vitro K562 model that can give high-levels of surface markers and globin expression. Potential clinical application of asciminib in hematological diseases that are associated specifically with a failure in the expression of globin genes should be evaluated. Keywords:K562, erythroid differentiation, asciminib, imatinib, glycophorin A, transferrin receptor, hemoglobin Citation Format: Hammad Hassan, Sarah Yousuf, Syed Muhammad Ahmed, Karim Ruknuddin, Hadiqa Raees, Sadia Habib, Fizza Iftikhar, Afsar Ali Mian, Elnasir Lalani. Asciminib activates erythroid differentiation in K562 cell line. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4040.

Abstract 5379: Deep learning enables label-free tracking of heterogeneous subpopulations

Abstract Observing and quantifying the proliferation of subpopulations in cancer is key to understanding how heterogeneous groups of cells interact and respond to therapy, their environment, and each other. Prior research has demonstrated that cell-state properties such as metastatic potential and genotype perturbation are encoded in cellular morphology and can be identified with various machine-learning approaches. This encoding spans multiple imaging modalities such as brightfield, phase contrast, and stained whole-slide images, and phenotype prediction can be accomplished using both classical and deep machine learning methods. Here we show that not only do these prediction capabilities extend to transcriptomic subpopulations, but that they can be used to track these populations in high throughput longitudinal live-cell imaging experiments. Using single-cell RNA sequencing, we observed that, among untreated MDA-MB-231 triple negative breast cancer cells, there exist two transcriptomically distinct populations of cells. Using fluorescence-activated cell sorting based on the differentially expressed surface marker ESAM, we isolated these subpopulations and fluorescently labeled them with mCherry or GFP depending on their transcriptomic cluster. Cells were then grown in monoculture or coculture and imaged every 4 hours at 20x resolution. To identify the associated transcriptomic cluster, we trained an instance segmentation algorithm, Mask R-CNN, to both segment and classify cells. We find that, despite being derived from the same cell line, these phenotypes can be predicted using phase contrast images alone. These results demonstrate that cellular phenotypes manifested by distinctive RNA expression signatures can now be surveilled in a high-throughput manner across multiple samples and conditions without further RNA sequencing or biomarker labeling. We anticipate that this methodology of high throughput tracking will be applicable to other heterogeneous subpopulations, such as isolated therapy-resistant or sensitive cells. Tracking transcriptomically distinct populations using only high-throughput imaging will increase the granularity of population analysis and enable more rapid assessment of cancer cell evolutionary dynamics. Citation Format: Tyler Jost, Andrea Gardner, Amy Brock. Deep learning enables label-free tracking of heterogeneous subpopulations. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5379.