Cells In Tumor Microenvironment Research Articles

TMOD-20. RAPID PROCESSING AND BIOBANKING OF RESECTED BRAIN TUMOR TISSUE TO GENERATE PATIENT-DERIVED BRAIN TUMOR EXPLANT ORGANOIDS (GBOS) FOR PRECLINICAL STUDIES

Abstract Improved preclinical tools are urgently needed to translate new brain cancer treatments. Patient-derived brain tumor explant organoids (GBOs) offer promise for studying tumor cells in a relevant human tumor microenvironment and predicting patient responses to therapy. However, generating GBOs is time-consuming, costly, and technically challenging, hindering the creation of comprehensive biobanks covering the spectrum of brain tumor heterogeneity. This work presents a semi-automated method for producing GBOs, involving tumor tissue processing, size selection, and same-day cryopreservation, reducing generation time to less than 1 hour. We established a biobank of 24 GBOs from 33 samples (11 males and 13 females) with primary (n=13, GBO Yield (GY)>90%) and recurrent (n=5, GY>90%) glioblastomas, high-grade gliomas (HGG, n=2, GY≤50%), and low-grade gliomas (LGG, n=2 with GY>90%, n=2 with GY≤50%). Using GBO size and propidium iodide as readouts, we used this biobank to compare anticancer activities of novel idronoxil-conjugated benzopyran compounds (NX786, NX904/904E1) against Bortezomib (100% cell death reference). NX786 and NX904/904E1 reduced GBO growth (≥50%) in all primary glioblastoma and one (of two) recurrent glioblastoma GBOs with milder effects in LGG GBOs. Two (of four) primary glioblastoma, one (of two) recurrent glioblastoma, and one LGG GBOs exhibited significant cell death (>60%) in response to NX904/904E1. In contrast, NX786 induced cell death in one (of three) primary glioblastoma (34% cell death) and one (of two) recurrent glioblastoma (71% cell death) GBOs but not in LGG GBOs, together showcasing varied responses across different brain tumors. Highly-passaged GBOs lacking the non-malignant tumor microenvironment were more susceptible to these treatments, underlining the tumor microenvironment’s critical role in responses to anticancer agents. We provide a new method for efficient processing and cryopreserving GBOs, enabling the establishment of large biobanks for patient-specific preclinical drug testing across brain tumor subgroups in a clinically relevant human 3D model.

TMIC-73. SEX DIFFERENCES IN INTERFERON-GAMMA RESPONSES IN GLIOMA MICROENVIRONMENT

Abstract IFNγ is a cytokine with both pro- and anti-tumorigenic effects and its role in glioma immunotherapy resistance is not well understood. In the tumor microenvironment, T and NK cells produce IFNγ, which affects cellular phenotypes in most of the cancer and stromal cells since IFNγ receptor is ubiquitously expressed. IFNγ induces expression of molecules that confer resistance to immunotherapies, such as PDL1, PDL2, IDO1, and iNOS. The goal of this study is to elucidate cell type-specific responses to IFNγ in immune competent glioma models we developed that are resistant to immunotherapy. We intracranially injected male and female murine glioma cells into B6 and Ifng-/- honst mice to measure overall survival and perform immune phenotyping and single cell RNA-sequencing analyses. Ifnγ-/- hosts exhibited a shorter survival, and the proportion of GBM cells is higher in Ifng-/- hosts compared to wild type, indicating that the net effect of IFNγ signaling in glioma is anti-tumorigenic. In a recent study, we published that IFNγ-response pathway is enriched in the mesenchymal-like (MES-like) subtype of human GBM cells, compared to neutral-progenitor-like (NPC-like) and oligodendrocyte-progenitor-like (OPC-like) cells (Abdelfattah et al., 2022). To test our hypothesis that IFNγ signaling induces MES transition in glioma cells in vivo, we compared fractions of glioma cell subtypes in wildtype and Ifng-/- male and female hosts. In female Ifng-/- mice, MES-like GBM cell fraction was reduced while OPC-like fraction was increased, supporting our hypothesis. However, there was no difference in male hosts. Furthermore, gliomas grown in female B6 hosts showed higher infiltration of immune cells (CD45+), lymphocytes (CD3+) and fewer resident microglia cells (CD11b+CD45int), compared with Ifng-/- female hosts. In contrast, no significant difference in immune cell infiltration was observed between B6 vs Ifng-/- males. These results suggest an unanticipated and complex context-dependent role of IFNγ signaling in GBM, which include sex differences in its role in immune cell recruitment and MES transition in glioma cells.

Integration of single-cell and spatial transcriptome sequencing identifies CDKN2A as a senescent biomarker in endothelial cells implicating hepatocellular carcinoma malignancy.

Highly complex tumor microenvironment makes hepatocellular carcinoma (HCC) as one of the most malignant tumors worldwide. The role of cellular senescence in HCC has been gradually recognized. The present study aimed to comprehensively elucidate the senescence-related features of HCC in single-cell and spatial dimension. Single-cell RNA sequencing (scRNA-Seq) data was used to clarify the heterogeneity of senescence-related genes (SRGs) among multiple cell types within HCC. Spatial transcriptome RNA sequencing (stRNA-Seq) data was used for depicting SRGs features in spatial dimension. A prognostic model based on SRGs was constructed by using of bulk sequencing (bulk-Seq) data of HCC. The cell-cell interaction of senescent endothelial cells (ECs) in tumor microenvironment was analyzed. Then, the role of senescent ECs was verified through in vitro and in vivo experiments. The level of senescence demonstrated substantial heterogeneity among different cell types within tumor microenvironment of HCC, where ECs exhibited the most prominent senescent phenotype. Senescent ECs activated specific regulatory pathways through communicating with other cell types, with a potential impact on tumor progression. Spatial analysis revealed senescent ECs mainly located in the core region of HCC. The interaction of senescent ECs and immune cells implicated their role in tumor progression and immunotherapeutic response. In addition, CDKN2A was identified as an independent risk factor for HCC prognosis by constructing a prognostic model. Patients with high risk displayed an even worse outcome. The experimental verification indicated senescence of ECs determined by CDKN2A exhibited a secretory phenotype. Furthermore, senescent ECs with CDKN2A overexpression promote the proliferation and migration of HCC. The present study recognizes the critical effect of senescent ECs defined by CDKN2A in the promotion of tumor progression, which sheds new light on the investigation of ECs senescence in HCC.

Editorial: Reciprocal crosstalk between the tumor microenvironment and cancer stem cells

Editorial: Reciprocal crosstalk between the tumor microenvironment and cancer stem cells

CITMIC: Comprehensive Estimation of Cell Infiltration in Tumor Microenvironment based on Individualized Intercellular Crosstalk.

The tumor microenvironment (TME) cells interact with each other and play a pivotal role in tumor progression and treatment response. A comprehensive characterization of cell and intercellular crosstalk in the TME is essential for understanding tumor biology and developing effective therapies. However, current cell infiltration analysis methods only partially describe the TME's cellular landscape and overlook cell-cell crosstalk. Here, this approach, CITMIC, can infer the cell infiltration of TME by simultaneously measuring 86 different cell types, constructing an individualized cell-cell crosstalk network based on functional similarities between cells, and using only gene transcription data. This is a novel approach to estimating the relative cell infiltration levels, which are shown to be superior to the current methods. The TME cell-based features generated by analyzing melanoma data are effective in predicting prognosis and treatment response. Interestingly, these features are found to be particularly effective in assessing the prognosis of high-stage patients, and this method is applied to multiple high-stage adenocarcinomas, where more significant prognostic performance is also observed. In conclusion, CITMIC offers a more comprehensive description of TME cell composition by considering cell-cell crosstalk, providing an important reference for the discovery of predictive biomarkers and the development of new therapeutic strategies.

Comprehensive Analysis and Verification of the Prognostic Significance of Cuproptosis-Related Genes in Colon Adenocarcinoma

Colon adenocarcinoma (COAD) is a frequently occurring and lethal cancer. Cuproptosis is an emerging type of cell death, and the underlying pathways involved in this process in COAD remain poorly understood. Transcriptomic and clinical data for COAD patients were collected from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. We investigated alterations in DNA and chromatin of cuproptosis-related genes (CRGs) in COAD. In order to identify predictive differentially expressed genes (DEGs) and various molecular subtypes, we used consensus cluster analysis. Through univariate, multivariate, and Lasso Cox regression analyses, four CRGs were identified. A risk prognostic model for cuproptosis characteristics was constructed based on four CRGs. This study also examined the association between the risk score and the tumor microenvironment (TME), the immune landscape, and drug sensitivity. We distinguished two unique molecular subtypes using consensus clustering analysis. We discovered that the clinical characteristics, prognosis, and TME cell infiltration characteristics of patients with multilayer CRG subtypes were all connected. The internal and external evaluations of the predicted accuracy of the prognostic model built using data derived from a cuproptosis risk score were completed at the same time. A nomogram and a clinical pathological analysis make it more useful in the field of medicine. A significant rise in immunosuppressive cells was observed in the high cuproptosis risk score group, with a correlation identified between the cuproptosis risk score and immune cell infiltration. Despite generally poor prognoses, the patients with a high cuproptosis risk but low tumor mutation burden (TMB), cancer stem cell (CSC) index, or microsatellite instability (MSI) may still benefit from immunotherapy. Furthermore, the cuproptosis risk score positively correlated with immune checkpoint gene expression. Analyzing the potential sensitivity to medications could aid in the development of clinical chemotherapy regimens and decision-making. CRGs are the subject of our in-depth study, which exposed an array of regulatory mechanisms impacting TME. In addition, we performed additional data mining into clinical features, prognosis effectiveness, and possible treatment medications. COAD’s molecular pathways will be better understood, leading to more precise treatment options.

Refining Diagnostic Subtypes of Peripheral T-cell Lymphoma Using a Multiparameter Approach

Peripheral T-cell lymphoma (PTCL) is a heterogeneous category, and many cases are unclassifiable and designated as PTCL-not otherwise specified (PTCL-NOS). Gene expression profiling (GEP) has delineated two prognostic subtypes within PTCL-NOS, PTCL-TBX21, and PTCL-GATA3, characterized by distinctive transcriptomes and a different prognosis. To further evaluate the pathologic features of these subgroups, 101 PTCL cases that did not meet specific criteria for well-defined T-cell lymphoma entities underwent detailed pathologic, immunophenotypic (including TFH biomarkers) and GEP analyses, separating them into PTCL-NOS (n=63) and PTCL-TFH (a.k.a. nodal PTCL-TFH, NOS, and TFH lymphoma, NOS) (n=38). PTCL-NOS cases were further categorized into PTCL-GATA3 (n=22; 34%) and PTCL-TBX21 (n=41; 66%), and a significant association (p < 0.02) with overall survival (OS) was reaffirmed. Histopathological assessment showed PTCL-GATA3 cases were characterized by monotonous medium-sized or large transformed cells with a minimal tumor microenvironment (TME) compared to PTCL-TBX21 cases, which consisted of pleomorphic cells in a polymorphous TME (p < 0.05). GEP analysis validated these TME distinctions. Immunophenotypic analysis showed that PTCL-GATA3 cases were predominantly CD4+CD8- and associated with significantly higher LEF1, MYC, and CD30 expression (p < 0.05). PTCL-TBX21 displayed a more diverse biomarker profile with two subgroups: one expressing cytotoxic antigens and enriched in CD8+CD4- or CD8-CD4- phenotype, and another lacking cytotoxic markers but showing a CD4+CD8- phenotype with increased ICOS expression, but devoid of other TFH markers. The PTCL-TFH cases correlated with an angioimmunoblastic T-cell lymphoma (AITL) gene signature, had more EBER-positive cells than the PTCL-GATA3 and PTCL-TBX21 cases, and a subset had some morphologic features of AITL (p < 0.01). This study highlights the unique morphologic and phenotypic variations within the newly-identified PTCL subtypes and should enable more precise diagnosis and tailored therapeutic strategies in the future.

PH sensitive lipid polymeric hybrid nanoparticle (LPHNP) of paclitaxel and curcumin for targeted delivery in breast cancer

Objective The study aimed at designing a pH sensitive Lipid polymeric Hybrid nanoparticle (LPHNP) for targeted release of Paclitaxel (PTX) and Curcumin (CUR) in breast cancer. Significance Such systems shall result in controlled triggered release in acidic microenvironment of tumor cells with improved pharmacokinetic profile. Methods Chitosan-coated CUR and PTX coloaded pH-sensitive LPHNPs were synthesized employing nanoprecipitation technique. The synthesized NPs were characterized in terms of particle size, polydispersity index (PDI), zeta potential, and morphology. Results LPHNPs co-loaded with curcumin (CUR) and paclitaxel (PTX) were successfully formulated, achieving a size of 146 nm, a PDI of 0.18, and an entrapment efficiency exceeding 90%. In vitro release studies demonstrated controlled release of CUR and PTX under tumor pH conditions showing 1.6 fold and 1.7 fold higher release in ABS pH 5 in comparison to PBS 7.4 for PTX and CUR respectively. MTT-assay studies revealed enhanced cytotoxicity of CUR and PTX as LPHNPs showing IC50 value of free CUR & PTX 480.06 µg/mL decreasing to 282.97 µg/mL for CS-CUR-PTX-LPHNPs. In vivo pharmacokinetic evaluations in rats confirmed significantly improved bioavailability, with a 3.8-fold increase in AUC for CUR and a 6.6-fold increase for PTX. Additionally, the LPHNPs demonstrated controlled release and prolonged retention, evidenced by a 2.2-fold increase in the half-life (t1/2) of CUR and a 1.3-fold increase in the half-life of PTX. Conclusions: The results underscores potential of chitosan-coated LPHNP as a promising delivery platform, offering high drug loading, optimal size for cellular penetration, and prolonged blood circulation for cancer.

“Balloon-like” biomimetic erythrocyte vesicles potentiate photodynamic therapy for inducing immunogenic cell death

Photodynamic therapy (PDT) for cancer is known for its minimal invasiveness and safe characteristics, but the hypoxic tumor microenvironment still limits efficacy. Herein, we have developed a novel “balloon-like” biomimetic erythrocyte vesicle, which is constructed by loading chlorin e6 (Ce6) and oxygenated hemoglobin (Hb) in a folate (FA)-modified, PEGylated liposome, denoted as Ce6-Hb-FA@lip (CHFL). The CHFL exhibits high biocompatibility and good stability in PBS solution. Moreover, CHFL possesses the “balloon-like” elastic structure for oxygen binding with the change of volume. Both in vitro and in vivo studies demonstrate an effective PDT of CHFL, which significantly reverses the hypoxic microenvironment of tumor cells through the targeted cotransmission of Ce6 and Hb. Additionally, this biomimetic erythrocyte vesicle can induce oxidative stress to enhance tumor immunogenicity and trigger immunogenic cell death (ICD). Thus, the dying tumor cells can activate both dendritic cells (DCs) and T lymphocytes, which, in turn, initiates the antitumor immune response by releasing the damage-associated molecular patterns (DAMPs). This effective and safe platform holds great promise in the development of nanomedicines for innovative oxygen-enhanced PDT in the treatment of cancer.

Tuning the Protonation Sensitivity of Weak Acidic Groups on a Zwitterionic Dendrimer for Selectively Targeting GD2-Overexpressed Tumor Cells in an Acidic Tumor Microenvironment.

Disialoganglioside (GD2) is one of the most popular overexpressed antigens for tumor cell targeting. However, GD2-specific antibodies often show unintended targeting to GD2-expressing health-maintaining cells due to the comparable binding affinities both at physiological pH and in a slightly acidic tumor microenvironment (TME). In this work, an affinity-switchable zwitterionic PAMAM G5 dendrimer (G5-3S) is developed for selective binding to GD2 only in a slightly acidic TME. It has 3 sulfonic groups, 128 carboxylic groups, and 125 amino groups on the surface. This affinity switch is realized by multiple hydrogen bond (H-bond) formation between protonated carboxylic groups surrounding a sulfonic group and overexpressed GD2 clusters on the tumor cell membrane in the slightly acidic TME, whereas there is no stable H-bond formation at physiological pH. Thus, G5-3S shows superior selectivity to GD2-overexpressed tumor cells over anti-GD2 antibodies by avoiding targeting GD2-expressing health-maintaining cells at physiological pH. This suggests that G5-3S is a promising candidate for GD2-overexpressed cancer treatment.

RNA methylation patterns of tumor microenvironment cells regulate prognosis and immunotherapeutic responsiveness in patients with triple-negative breast cancer

Immunotherapy research focuses on reshaping the tumor microenvironment (TME) to enhance its antitumor immune responses, with an emphasis on understanding the impact of RNA methylation in triple-negative breast cancer (TNBC) TME regulation. This study explored the influence of various RNA methyltransferases on TME cells in TNBC and their correlation with prognosis and immunotherapy response. Using non-negative matrix factorization on single-cell RNA-sequencing data, distinct TME cell clusters were identified based on the expression of 30 RNA methyltransferases. Various analyses, including pseudotime, cell communication, transcription factor regulatory network, and gene enrichment, were conducted on these clusters. The roles of RNA methyltransferase-mediated TME clusters in prognosis and immunotherapy response were determined using TNBC bulk RNA-Seq data, and the findings were validated through immunofluorescence analysis of a tissue microarray comprising 87 samples. Spatial transcriptomic analysis further revealed the distribution of TME cell clusters. Different methyltransferase-mediated cell clusters exhibited unique metabolic, immune, transcriptional, and intercellular communication patterns. Survival analysis indicated prognostic significance in specific TME cell clusters, and immunofluorescence analysis confirmed the prognostic value of m6A_WTAP + CD8T + cells. In conclusion, our study illustrated the involvement of these cell subgroups in tumor growth and antitumor immunity modulation, providing insights into the enhancement of TNBC immunotherapy.

Construction of an Innovative Nanogel and Its Applications for Achieving Chemo-Immunotherapy of Tumors.

Malignant tumors, also known as cancers, are a global public health problem. Nanogels are promising carriers for the delivery of anticancer medicines. Therefore, based on the unique microenvironment of tumor cells and the advantages of nanogels, a simple and economical one-pot synthesis method was designed to construct natural polysaccharide-based redox-responsive nanogels (LDD NGs). The enhanced permeability and retention (EPR) effect enriched LDD NGs in tumor cells, which then rapidly collapsed and released the natural antitumor drug diosgenin (DG) and the natural polysaccharide lentinan (LNT) via the depletion of a high level of reduced glutathione (GSH) in tumor cells, resulting in a synergistic therapeutic effect of chemotherapy and immunotherapy. In vivo antitumor experiments showed that LDD NGs could inhibit the proliferation and metastasis of the A549 lung cancer cells. Further studies indicated that LDD NGs could increase the production of ROS and induce apoptosis of A549 cells. In addition, LNT released from LDD NGs could promote the proliferation of dendritic cells, increase the production of NO, and upregulate the expressions of the costimulatory molecules CD40, CD80, CD86, and MHC-II. The construction of LDD NGs was a novel drug synthesis approach that could provide fresh ideas for the development of polysaccharide-based redox-responsive drug delivery systems.

An insight into the role of innate immune cells in breast tumor microenvironment.

The immune background of breast cancer is highly heterogeneous and the immune system of the human body plays a dual role by both promoting and suppressing its progression. Innate immune cells are the first line of defense in the immune system and impart protection by identifying and interacting with foreign pathogens and cancer cells. Different innate immune cells like natural killer cells, macrophages, dendritic cells, and myeloid suppressor cells take part in hosting the cancer cells. Autophagy is another key component inside the tumor microenvironment and is linked to the disintegration and recycling of cellular components. Within the tumor microenvironment autophagy is involved with Pattern Recognition Receptors and inflammation. Various clinical studies have shown prominent results where innate immune cells and autophagy in combination are used for pathogen as well as cancer cell clearance. However, it is necessary to comprehend the complex tumor microenvironment so that different therapeutic approaches can be developed to enhance the suppressive actions of the cells toward breast cancer cells. In this review article, the complex interaction between immune cells and breast cancer cells and their role in developing effective immunotherapies to improve patient outcomes are discussed in detail.

Convergent inducers and effectors of T cell paralysis in the tumour microenvironment.

Tumorigenesis embodies the formation of a heterotypic tumour microenvironment (TME) that, among its many functions, enables the evasion of T cell-mediated immune responses. Remarkably, most TME cell types, including cancer cells, fibroblasts, myeloid cells, vascular endothelial cells and pericytes, can be stimulated to deploy immunoregulatory programmes. These programmes involve regulatory inducers (signals-in) and functional effectors (signals-out) that impair CD8+ and CD4+ T cell activity through cytokines, growth factors, immune checkpoints and metabolites. Some signals target specific cell types, whereas others, such as transforming growth factor-β (TGFβ) and prostaglandin E2 (PGE2), exert broad, pleiotropic effects; as signals-in, they trigger immunosuppressive programmes in most TME cell types, and as signals-out, they directly inhibit T cells and also modulate other cells to reinforce immunosuppression. This functional diversity and redundancy pose a challenge for therapeutic targeting of the immune-evasive TME. Fundamentally, the commonality of regulatory programmes aimed at abrogating T cell activity, along with paracrine signalling between cells of the TME, suggests that many normal cell types are hard-wired with latent functions that can be triggered to prevent inappropriate immune attack. This intrinsic capability is evidently co-opted throughout the TME, enabling tumours to evade immune destruction.

Extracellular vesicles in cancer drug resistance: Mechanistic insights and therapeutic implications

AbstractDespite significant advancements in the treatment of cancer, therapeutic resistance remains a major hurdle for the achievement of full cures. Besides being typically driven by intratumoral heterogeneity, such acquired resistance also relies heavily on cell‐cell communication whereby extracellular vesicles (EVs) carrying resistance‐related components can be transferred from drug‐resistant cells or nontumorigenic members within tumor microenvironment (TME) to their sensitive neighbors. The cargo and membrane surface proteins of EVs derived from drug‐resistant cells and TME cells carry abundant biological information, transferring therapy‐resistant capacity to sensitive cancer cells. Hence, a deep understanding of the roles of EVs in cancer therapy resistance will facilitate identifying biomarkers and developing new approaches to restore therapy sensitivity. In this review, we summarize our current understanding regarding the causes and effects of EV‐mediated cell–cell communication in drug resistance, with a particular notice on how various kinds of cargoes derived from different cells within TME are linked to the resistant phenotype. We also discuss how this knowledge can contribute to improvements in clinical practice, that is, the opportunities and challenges of EVs in functioning as potential biomarkers in predicting therapeutic resistance and, by extension, EV‐based therapy in achieving deeper and longer‐lasting clinical responses.

Acquired Bortezomib Resistance in Multiple Myeloma:From Mechanisms to Strategy.

Multiple myeloma (MM) is a heterogeneous plasma cell tumor with a survival period of several months to over ten years. Despite the development of various new drugs, MM is still incurable and recurs repeatedly. Bortezomib, a landmark event in the history of MM treatment, has dramatically improved the prognosis of patients with MM. Although proteasome inhibitors (PIs) represented by bortezomib, have greatly prolonged MM survival, unfortunately, almost all MM will develop bortezomib resistance, leading to relapse with a shorter survival. It has been reported that both the tumor microenvironment and myeloma cells drive bortezomib resistance. Multiple treatment methods have been attempted to overcome bortezomib resistance, but unfortunately, there has been no breakthrough. It is believed that the key resistance mechanism has not yet been discovered. A deeper understanding of the mechanism of bortezomib resistance and strategies to overcome it can help identify key resistance mechanisms and further improve the prognosis of MM.

Histone deacetylase inhibition disrupts the molecular signature of the glioblastoma secretome related to extracellular vesicle-associated proteins and targets RAB7a and RAB14 in vitro

Glioblastoma (GBM) is the most aggressive brain tumor with a poor prognosis. While Histone Deacetylase inhibitors have shown promising results in inhibiting cancer cell invasion and promoting apoptosis, their effects on GBM secretion, specifically focusing on extracellular vesicles (EVs) secretion, remain largely unexplored. Using label-free NANOLC-MS/MS methodology, we identified significant changes in the abundance of membrane traffic regulatory proteins in the secretome of U87MG cells after the treatment with the HDAC inhibitor Trichostatin A (TSA). In silico analysis showed that TSA treatment disrupted the secretion pattern of EVs-associated proteins and cellular signaling pathways, both qualitatively and quantitatively. Notably, RAB14/RAB7a interaction was only observed in the secretome of cells treated with TSA. In vitro assays revealed that TSA treatment of glioma cells increased EVs secretion and intracellular protein levels of RAB7a and RAB14 without affecting gene expression, suggesting a role of these two EVs-associated proteins in grade IV glioma cells. Additionally, an integrative approach using clinical data highlighted a correlation between DNA mutations affecting vesicle traffic coding-genes and clinical and phenotypic outcomes in glioma patients. These findings provide insights into the interplay between epigenetics and GBM intracellular trafficking, potentially leading to improved strategies for targeting and modifying the complex signaling network established between GBM cells and the tumor cell microenvironment.

Dynamic reciprocal interactions between activated T cells and tumor associated macrophages drive macrophage reprogramming and proinflammatory T cell migration within prostate tumor models

Tumor-associated macrophages (TAMs) have been implicated as a tumor microenvironment (TME) cell population, which may be playing a vital role in the inhibition of effective T cell responses in the prostate TME. In this manuscript, we leverage a novel microscale cell culture platform, known as Stacks, to investigate mono-, co-, and tri-culture TME models comprised of prostate tumor cell lines, primary macrophages, and autologous T cells from patients with prostate cancer. Through multiplexed analysis of these multi-cellular prostate tumor models, we capture a dynamic interaction between primary TAMs and activated T cells that resulted in reciprocal proinflammatory activation of both cell populations upon interaction. These findings suggest that activated T cells are capable of reprogramming immunosuppressive TAMs in the context of prostate tumor models and that TAM reprogramming may play a key supportive role in restoring proinflammatory T cell tumor responses in the prostate TME.

Dysgerminomas: germ cell tumors exhibit high expression of PD-L1 and associated with high TILs and good prognosis

Ovarian germ cell tumors (OVGCTs) account for 28% of all diagnosed ovarian cancers, and malignant germ cell tumors specifically account for approximately 13% of diagnosed ovarian cancers in Saudi Arabia. Although most germ cell tumor patients have a high survival rate, patients who experience tumor recurrence have a poor prognosis and present with more aggressive and chemoresistant tumors. The use of immunotherapeutic agents such as PD-L1/PD-1 inhibitors for OVGCTs remains very limited because few studies have described the immunological characteristics of these tumors. This study is the first to investigate PD-L1 expression in ovarian germ cell tumors and explore the role of PD-L1 expression in tumor microenvironment cells and genetic alterations. A total of 34 ovarian germ cell tumors were collected from pathology archives. The collected tumor tissues included ten dysgerminomas, five yolk sac tumors, five immature teratomas, and one mature teratoma, and the remaining samples were mixed germ cell tumors. The tumors were analyzed using immunohistochemical analysis to determine PD-L1 expression, immune cell infiltration and cancer stem cell populations and their correlation with clinical outcome. Furthermore, the genetic alterations in different subtypes of germ cell tumors were correlated with PD-L1 expression and clinical outcome. Datasets for testicular germ cells (TGCTs) were retrieved from The Cancer Genome Atlas (TCGA) and analyzed using cBioPortal (cbioportal.org) and Gene Expression Profiling Interactive Analysis (GEPIA). Compared with yolk sac tumors, dysgerminomas highly express PD-L1 and are associated with high levels of tumor infiltrating lymphocytes (TILs) and stem cell markers. In addition, compared with PD-L1-negative yolk sac tissue, dysgerminomas/seminomas with high PD-L1 expression are associated with more genetic alterations and a better prognosis. Our findings will contribute to the knowledge about the potential benefits of ovarian cancer immunotherapy in specific subsets of germ cell tumor patients and the risk factors for resistance mediated by tumor microenvironment cells.

Making the effect visible - OX40 targeting nanobodies for in vivo imaging of activated T cells.

Human OX40 (hOX40/CD134), a member of the TNF receptor superfamily, is mainly expressed on activated T lymphocytes. Triggered by its ligand OX40L (CD252), it provides costimulatory signals that support the differentiation, proliferation and long-term survival of T cells. Besides being a relevant therapeutic target, hOX40 is also an important biomarker for monitoring the presence or infiltration of activated T cells within the tumor microenvironment (TME), the inflammatory microenvironment (IME) in immune-mediated diseases (IMIDs) and the lymphatic organs. Here, we developed novel single domain antibodies (nanobodies, Nbs) targeting hOX40 to monitor the activation status of T cells by in vivo molecular imaging. Nbs against hOX40 (hOX40-Nbs) were selected from an immunized Nb-library by phage display. The identified hOX40-Nbs were characterized in vitro, including determination of their specificity, affinity, stability, epitope recognition and their impact on OX40 signaling and T cell function. A lead candidate was site-specifically conjugated with a fluorophore via sortagging and applied for noninvasive in vivo optical imaging (OI) of hOX40-expressing cells in a xenograft mouse model. Our selection campaign revealed four unique Nbs that exhibit strong binding affinities and high stabilities under physiological conditions. Epitope binning and domain mapping indicated the targeting of at least two different epitopes on hOX40. When analyzing their impact on OX40 signaling, an agonistic effect was excluded for all validated Nbs. Incubation of activated T cells with hOX40-Nbs did not affect cell viability or proliferation patterns, whereas differences in cytokine release were observed. In vivo OI with a fluorophore-conjugated lead candidate in experimental mice with hOX40-expressing xenografts demonstrated its specificity and functionality as an imaging probe. Considering the need for advanced probes for noninvasive in vivo monitoring of T cell activation dynamics, we propose, that our hOX40-Nbs have a great potential as imaging probes for noninvasive and longitudinal in vivo diagnostics. Quantification of OX40+ T cells in TME or IME will provide crucial insights into the activation state of infiltrating T cells, offering a valuable biomarker for assessing immune responses, predicting treatment efficacy, and guiding personalized immunotherapy strategies in patients with cancer or IMIDs.