Changes In Immune Microenvironment Research Articles

Abstract C016: Age dictates immune response within the tumor microenvironment of triple negative breast cancer

Abstract Age is the biggest risk factor for developing most forms of cancer. In breast cancer, over 50% of patients are over 60 years old; however, less than 25% of patients enrolled in clinical trials are in this age bracket. Furthermore, most mouse modeling is performed in young mice, meaning that from preclinical through clinical stages patients ages are not accurately reflected in trials designs. Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer with no targeted therapies, so many treatment strategies utilize chemotherapy in combination with immunotherapy – which relies on a functional immune response. It is well known that immune function declines as we age, and thus therapeutic responses may differ with age. It is yet unclear how the tumor immune microenvironment changes with age, and how this may impact therapeutic response. Here, we utilize a mouse model which mimics hallmarks of human immune aging to understand how age impacts TNBC immune responses to dictate disease progression and therapeutic response. Immunologically young (8 weeks old) and aged (∼12 months old) FVB mice were orthotopically injected with syngeneic Met1 TNBC cells. Once tumors became palpable, mice were treated with paclitaxel chemotherapy or vehicle control and/or anti-PDL1 immunotherapy to mimic first-line therapeutic strategies. Tumors grew significantly faster in young control mice compared to aged, but young mice had a more robust response to therapy. Notable, only young mice had a significant benefit of combo therapy over monotherapy alone. Despite aged mice having more circulating CD8+ and CD4+ T cells, tumors in aged mice had significantly more infiltration of CD8+ cytotoxic T cells and FOXP3+ inhibitory T-regulatory cells compared to young control mice, yet only tumors in young mice exhibited an increase in T cell infiltration with therapy. Additionally, the ratio of CD8+ T cells and FOXP3+ Tregs was unchanged with age or treatment. Depletion of either CD8+ or CD4+ T cells led to a complete loss of age-associated differences in tumor growth. RNA sequencing analysis suggests that infiltrating T cells in aged mice may be exhausted due to a chronic interferon (IFN) phenotype, indicated by enrichment of IFN-alpha, IFN-gamma, and IL2 pathways, as well as increased expression of immune exhaustion markers PD1, CTLA4, TIM3 and LAG3. Neutralization of IFN-gamma blocks therapeutic response to anti-PDL1 in young mice but has no impact on aged mice. Analysis of published single cell RNAseq data indicated the same IFN response pathways enriched with age in human TNBC. These results demonstrate that the aging tumor immune microenvironment significantly impacts tumor progression and therapeutic response and suggest that targeting IFN signaling may lead to improved therapeutic responses. Together these findings establish a significant impact of immune aging on TNBC disease progression and response to therapy, highlighting the importance of developing age- stratified treatment strategies to improve responses in patients of all ages. Citation Format: Milos Spasic, Adrienne Parsons, Abigail Recko, Elizabeth Mittendorf, Peter van Galen, Sandra McAllister. Age dictates immune response within the tumor microenvironment of triple negative breast cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C016.

TMIC-84. MOLECULAR EVOLUTION OF THE TUMOR AND ITS MICROENVIRONMENT AT RECURRENCE

Abstract Changes in the glioma immune microenvironment at recurrence may contribute to disease progression and therapeutic resistance. In prior studies we demonstrated that the circumscribed glioma, pleomorphic xanthoastrocytoma (PXA), was relatively immune enriched including activated cytotoxic CD8+ T cells and Iba1+ microglia/macrophages. While PXA are often low-grade, a significant fraction can recur and progress to higher grade. To determine how the tumor and its immune microenvironment changes with recurrence, we examined a cohort of tumors from patients with multiple resections. Using single-nucleus RNA sequencing (snRNAseq) and spatial molecular imaging we investigate the temporal changes in the tumor and its microenvironment. To begin, we analyzed samples from three patients with paired initial and recurrent tumor. A total of 22,465 immune and non-immune cells were analyzed. Compared to the initial, the recurrent tumor tended to have decreased numbers of T cells and T cells had lower expression of CD2 and GZMA. Pathway analysis for DE genes in TAMs demonstrated enrichment of genes associated with NTRK signaling, while pathways related to aerobic respiration and mitochondrial translation were decreased suggesting a less inflammatory phenotype. Tumor cells at recurrence demonstrated decreased expression of CD274 (PD-L1) and of the chemokine CXCL14, previously identified as a factor driving an anti-tumor CD8+ T cell response. In a cohort of 5 patients with paired initial and recurrent tumors, we observed increased numbers of CD163+ TAMs. Together these data suggest changes in the tumor-associated immune response at recurrence that may be relevant to therapy. Using murine models for the disease we are investigating the factors that regulate these changes.

TMOD-13. IDENTIFYING MOLECULAR SIGNATURES OF PPM1D-MUTANT DIPGS

Abstract Diffuse Intrinsic Pontine Glioma (DIPGs) are universally fatal pediatric tumors with a median survival of only 9-12 months. PPM1D-truncating mutations (PPM1Dtr), which promote its phosphatase activity and suppress TP53 function, are found in approximately 15% of DIPG tumors. PPM1Dtr are mutually exclusive to TP53 mutations, and present unique therapeutic opportunities to reactivate wild-type TP53. Another distinct feature of PPM1Dtr DIPGs is the co-occurrence of PI3K/AKT/mTOR pathway alterations, such as PIK3CA. There is an unmet need to elucidate the underlying molecular mechanisms of DIPG and identify novel therapeutic vulnerabilities that will improve outcomes of this devastating tumor. We hypothesize that PPM1D-mutant DIPGs can be therapeutically targeted by reactivating the p53 signaling pathway and other complementary pathways which cooperate with PPM1Dtr. To investigate this, we have generated Trp53- and Ppm1d-mutant isogenic DIPG murine models to determine how specific oncogenic alterations function in DIPG formation, growth and treatment sensitivity. Current studies aim to examine differences in sensitivity to standard of care treatment modalities and leverage next generation sequencing techniques to uncover additional vulnerabilities. We found notable differences upon addition of PIK3CA mutations in the context of PPM1Dtr DIPG tumor formation, growth, survival, and lineage identity. Ongoing studies using whole genome transcriptomics to compare tumor models will provide insight into the molecular signals and cell state changes driven by individual genetic alterations. Furthermore, by comparing isogenic TP53 and PPM1Dtr mutant DIPG models, we aim to further delineate the molecular mechanisms that drive differential sensitivity of TP53 wild-type tumors. The immune-competent nature of our murine models also provides us with a unique opportunity to delineate tumor immune microenvironment changes. Leveraging this information and our novel murine models, our long-term goal is to develop combinatorial therapeutic strategies to improve outcomes for this deadly disease.

Photo-Thermally Controllable Tumor Metabolic Modulation to Assist T Cell Activation for Boosting Immunotherapy.

Glycolysis is crucial for tumor cell proliferation, supporting their energy needs and influencing the tumor microenvironment (TME). On one hand, increased lactate levels produced by glycolysis acidifies the TME, inhibiting T cell activity. On the other hand, glycolysis promotes the expression of PD-L1 through various mechanisms, facilitating immune evasion. Therefore, controlled modulation of glycolysis in tumor cells to subsequently improve the immune tumor microenvironment holds significant implications for clinical cancer treatment and immune regulation. To reverse the immunosuppressive microenvironment caused by tumor glycolysis and reduce tumor immune escape, we developed a photo-thermal-controlled precision drug delivery platform to regulate tumor metabolism and aid in the activation of T cells, thereby enhancing immunotherapy. First, hollow mesoporous Prussian blue (HPB) was prepared, and the glycolysis inhibitor 3-bromopyruvate (3-BrPA) was encapsulated within HPB using the phase-change material 1-tetradecanol, resulting in B/T-H. This product was then modified with tumor cell membranes to obtain a photo-thermal controllable regulator (B/T-H@Membrane, B/T-HM). Due to the excellent drug loading and photo-thermal properties of HPB, upon reaching the tumor, B/T-HM can rapidly heat under 808 nm irradiation, causing the 1-tetradecanol to transition to a liquid phase and release 3-BrPA, which effectively inhibits tumor glycolysis through the HK2 pathway, thereby reducing tumor cell proliferation, decreasing lactate production, and downregulating tumor PD-L1 expression. In synergy with photo-thermal and αPD-1, this photo-thermally controllable metabolic-immune therapy effectively activates T cells to eliminate tumor. In response to the changes in immune microenvironment caused by tumor metabolism, a photo-thermal precision-controlled drug delivery platform was successfully developed. This platform reshapes the tumor immunosuppressive microenvironment, providing a new approach for T cell-based tumor immunotherapy. It also opens new avenues for photo-thermal controllable metabolic-immune therapy.

Single-cell transcriptome analysis reveals immune microenvironment changes and insights into the transition from DCIS to IDC with associated prognostic genes

BackgroundDuctal carcinoma in situ (DCIS) of the breast is an early stage of breast cancer, and preventing its progression to invasive ductal carcinoma (IDC) is crucial for the early detection and treatment of breast cancer. Although single-cell transcriptome analysis technology has been widely used in breast cancer research, the biological mechanisms underlying the transition from DCIS to IDC remain poorly understood.ResultsWe identified eight cell types through cell annotation, finding significant differences in T cell proportions between DCIS and IDC. Using this as a basis, we performed pseudotime analysis on T cell subpopulations, revealing that differentially expressed genes primarily regulate immune cell migration and modulation. By intersecting WGCNA results of T cells highly correlated with the subtypes and the differentially expressed genes, we identified six key genes: FGFBP2, GNLY, KLRD1, TYROBP, PRF1, and NKG7. Excluding PRF1, the other five genes were significantly associated with overall survival in breast cancer, highlighting their potential as prognostic biomarkers.ConclusionsWe identified immune cells that may play a role in the progression from DCIS to IDC and uncovered five key genes that can serve as prognostic markers for breast cancer. These findings provide insights into the mechanisms underlying the transition from DCIS to IDC, offering valuable perspectives for future research. Additionally, our results contribute to a better understanding of the biological processes involved in breast cancer progression.

1336P Clinical outcomes, toxic effect, and changes of immune microenvironment of drug-eluting beads bronchial artery chemoembolization (DEB-BACE) combined with immunotherapy in the treatment of elder patients with non-small cell lung cancer

1336P Clinical outcomes, toxic effect, and changes of immune microenvironment of drug-eluting beads bronchial artery chemoembolization (DEB-BACE) combined with immunotherapy in the treatment of elder patients with non-small cell lung cancer

587. PD-L1 EXPRESSION AND CD8+ TUMOR-INFILTRATING LYMPHOCYTES CHANGES AFTER PREOPERATIVE CHEMORADIOTHERAPY IN ESOPHAGEAL SQUAMOUS CELL CARCINOMA

Abstract Background Neoadjuvant chemoradiotherapy (nCRT) has been established as a standard treatment for locally advanced esophageal squamous cell carcinoma (SqCC), but there are still insufficient research advances on the incorporation of immunologic agents. The aim of this study was to explore immune microenvironment changes before and after nCRT. Methods A total of 101 patients who underwent nCRT followed by radical surgery for esophageal SqCC in a single institution between 2005 and 2021 were analyzed. Pre-nCRT endoscopic biopsy and post-nCRT surgical specimen were evaluated using tissue microarray. Immunohistochemical staining for CD3, CD8, and PD-L1 were performed. Tumor-infiltrating lymphocytes (TIL) density were independently evaluated by blinded pathologist (total number of 2+ to 3+ cells/total area (mm2)). Results Compared to pre-nCRT biopsy, PD-L1 expression (8.7% vs. 14.0%, p<0.001) and TIL density (259.1 vs. 566.9, p<0.001) were significantly increased in surgical specimen after nCRT. When divided into groups according to nCRT response, post-nCRT TIL density (p=0.341), fold changes of TIL density (p=0.749), and PD-L1 expression (p=0.642) were not significantly different between ypCR (n=23) and non-ypCR group (n=78). In ypT0 group (n=36), post-nCRT TIL density was marginally higher than that of non-ypT0 group (404 vs. 259, p = 0.050). Conclusion Irrespective of clinical responses, PD-L1 expression and TIL density were both increased after nCRT. Our results could help the development of combination strategy of immunologic drugs and seek the possibility of an organ-saving strategy that will contribute to improving quality of life of patients.

Analysis of metastasis‑related risk factors and clinical relevance in adult soft‑tissue sarcoma.

Metastasis occurs in nearly 50% of cases of adult soft-tissue sarcoma (ASTS), leading to a dismal prognosis, with a 2-year survival rate of ~30%. Consequently, a prognostic model that incorporates metastatic characteristics may be instrumental in predicting survival time and in crafting optimal personalized therapeutic strategies for patients with ASTS. In the present study, a prognostic prediction model for ASTS was developed by examining genes that are differentially expressed between non-metastatic and metastatic patients in the Gene Expression Omnibus dataset. The prognostic model, which includes five featured genes [actin γ2 (ACTG2), apolipoprotein D, coatomer protein complex subunit γ2 imprinted transcript 1, collagen type VI α6 chain and osteomodulin], was further validated in patients with ASTS from the Cancer Genome Atlas dataset. Based on these five-gene signatures, patients were categorized into high- and low-risk groups. Functional and pathway analyses revealed disparities in stemness, extracellular matrix and cell adhesion-related pathways between the two risk groups, particularly noting the activation of the PI3K-Akt pathway in high-risk cases. Analysis of immune infiltration also revealed variations in immune microenvironment changes between the two risk groups. Immunohistochemical staining substantiated the prognostic significance of these gene signatures in a specific sarcoma subtype. Additionally, wound-healing and Transwell assays demonstrated that inhibition of ACTG2 by shRNAs curbed cell migration and invasion in a sarcoma HOS cell line, underscoring its role in sarcoma metastasis. In conclusion, the present study successfully developed and validated a metastasis-based prognosis prediction model. This model not only reliably forecasts the survival of patients with ASTS, but also may pave the way for further investigation into the processes underlying sarcoma metastasis, ultimately aiding in the design of tailored therapeutic regimens.

Regulation of vascular remodeling by immune microenvironment after the establishment of autologous arteriovenous fistula in ESRD patients.

Autogenous arteriovenous fistula (AVF) is the preferred dialysis access for receiving hemodialysis treatment in end-stage renal disease patients. After AVF is established, vascular remodeling occurs in order to adapt to hemodynamic changes. Uremia toxins, surgical injury, blood flow changes and other factors can induce inflammatory response, immune microenvironment changes, and play an important role in the maintenance of AVF vascular remodeling. This process involves the infiltration of pro-inflammatory and anti-inflammatory immune cells and the secretion of cytokines. Pro-inflammatory and anti-inflammatory immune cells include neutrophil (NEUT), dendritic cell (DC), T lymphocyte, macrophage (Mφ), etc. This article reviews the latest research progress and focuses on the role of immune microenvironment changes in vascular remodeling of AVF, in order to provide a new theoretical basis for the prevention and treatment of AVF failure.

Abstract 187: Macrophage instead of leukemia cell expressed PD-L1 drives T cell exhaustion and immune evasion of BCRABL1 chronic myeloid leukemia

Abstract BCR-ABL1 fusion gene is the hall marker of chronic myeloid leukemia (CML). Currently, the immune microenvironment of BCRABL1 CML remains largely unexplored. Our recent investigation in a transgenic mouse model of BCRABL1 CML revealed a continuous increase in CD11b+Ly6Cint PMN-MDSC with the progression of the disease. Concurrently, there was an increase in CD11b+Ly6Chigh M-MDSC and F4/80+ macrophages. However, The levels of CD4+ T cells, CD8+ T cells, CD19+ B cells, and CD49b+ NK cells, which are essential for tumor-killing significantly decreased. This immune phenotype was consistently observed in both primary leukemia induction and following serial transplantation of cells from primary leukemic mice. Intriguingly, only recipient mice subjected to sublethal irradiation developed the disease, while mice with intact immune system remained disease-free, which underscores the vital role of the immune system in the development of CML. The predominant presence of CD11b+Ly6Cint PMN-MDSC in the peripheral blood, bone marrow and spleen implies these cells may be at least partially consisted of CML leukemia cells. To examine the hypothesis, qRT-PCR and immunofluorescence (IF) staining were conducted. In both assays, Ly6G+ cells from BCRABL1 mice coexpressed the BCRABL1 oncogene. Furthermore, when co-cultured with CD4 T cells, the division of T cells was significantly inhibited, implying immune suppression by the Ly6G+ PMN-MDSCs and/or CML leukemia cells. In addition, the immuosuppressive pathway genes including Arg1, Hif1a, Enptd1, TGFβ were significantly upregulated. To investigate the possible role of the PD1/PDL1 axis in the BCRABL1 model, flow cytometry analysis was conducted. Unexpectedly, PDL1 was barely expressed in CML leukemia cells, whereas the expression of PDL1 in M-MDSCs and macrophages significantly increased, accompanied by remarkable upregulation of PD1 expression on CD4 T cells and CD8 T cells during leukemia progression. In other words, PDL1 expression on macrophages, rather than leukemia cells, was found to induce T cell exhaustion. For translational purpose, mice transplanted with the primary CML leukemia cells were treated with chemotherapy drugs ponatinib alone or in combination with the anti-PD1 antibody. Compared with the chemotherapy alone group, the mice in the combinational therapy group exhibited rapid remission and better disease control. Most importantly, the disease relapse occurred at a slower rate after treatment discontinuation, suggesting the value of combinational therapy in achieving treatment free remission. In summary, our study not only revealed the dynamic changes of immune microenvironment in the BCRABL1 CML mouse model, but also revealed the different mechanisms underlying immune evasion of BCR-ABL1 CML leukemia cells, which sheds light on a combinational treatment for achieving the treatment free remission of CML. Citation Format: Xiaocui Lu, Hui Fang, Xuexiu Fang, Atsuko Matsunaga, Kebin Liu, Jorge Cortes, John K. Cowell, Tianxiang Hu. Macrophage instead of leukemia cell expressed PD-L1 drives T cell exhaustion and immune evasion of BCRABL1 chronic myeloid leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 187.

Neoadjuvant toripalimab plus CapeOX in patients with localized dMMR/MSI-H gastric or esophagogastric junction adenocarcinoma (GC/EGJC): Results from the cohort C of phase II NICE trial.

349 Background: Surgery is the cornerstone of curative therapy for localized GC or EGJC and perioperative chemotherapy seems ineffective for those with dMMR/MSI-H tumors. Chemotherapy may booster antitumor immunity. There is a compelling need to investigate the efficacy of perioperative immunochemotherapy for those with dMMR/MSI-H tumors. Methods: NICE trial is a multicenter, multi-cohort phase II trial (NCT04744649) investigating the safety and efficacy of toripalimab combined with CapeOX regimen as perioperative treatment for localized GC or EGJC of PD-L1 CPS≥5 (IHC 22C3) (cohort A), EBV-positive (cohort B), and dMMR/MSI-H (cohort C). Among those cohorts, the cohort A was compared with the control group of perioperative CapeOX regimen in a randomized controlled trial manner, while the cohort B and C were single arm. In present study, we report the findings of Cohort C, and the patients (pts) received toripalimab 240 mg combined with standard dose CapeOX regimen q3 weeks for 4 cycles before and after surgery. The eligible tumor stages were cT3-4aNxM0 or cT2N+M0 diagnosed by chest and abdominal CT combined with staging laparoscopy as well as negative peritoneal cytology. The primary endpoint was major pathologic response (MPR, <10% viable cells) rate. Multiplex fluorescence immunohistochemistry (mIHC) was utilized to explore changes of immune microenvironment. Results: Between March 2021 and April 2023, 15 pts with dMMR/MSI-H localized GC/GEJC were recruited in Cohort C. Tumor stages were cT3N0(n=2), cT3N1-3 (n=2), cT4aN0 (n=1) and cT4aN1-3 (n=10). 14 pts completed all 4 cycles therapy preoperatively and one patient completed 2 cycles therapy because of AEs. None had disease progression, while one achieved a complete clinical response at radiology and endoscopy and refused surgery and the other 14 pts underwent resection. The R0 resection rate was 100% (14/14). The MPR rate was 92.9% (13/14) and the residual tumor percentage was 33.8% in the other one patient (cT4aN2). pCR rate was 78.6% (11/14). Therapy-related grade 3/4 AEs occurred in 5 pts of safety population (n=15). One patient occurred grade 3 immune-related liver toxicity after 2 cycles treatment and recovered after steroids therapy. No pts died during the perioperative treatment, and one patient died of COVID-19 238 days after surgery without relapse. No disease relapse was observed in all pts. The mIHC revealed a significant reduction in CD20+ B cells, CD3+ T cells, NK dim cells, and M1 macrophages within tumor area after treatment for patients who reached pCR. Conclusions: Neoadjuvant toripalimab and CapeOX regimen for the localized dMMR/MSI-H GC/GEJC is safety with high MPR rate. These data indicate that neoadjuvant immunochemotherapy may potentially become one of the treatment options for these patients. Clinical trial information: NCT04744649 .

An oncolytic system produces oxygen selectively in pancreatic tumor cells to alleviate hypoxia and improve immune activation

IntroductionHypoxia is one of the important reasons for the poor therapeutic efficacy of current pancreatic cancer treatment, and the dense stroma of pancreatic cancer restricts the diffusion of oxygen within the tumor. MethodsA responsive oxygen-self-supplying adv-miRT-CAT-KR (adv-MCK) cascade reaction system to improve hypoxia in pancreatic cancer is constructed. We utilized various experiments at multiple levels (cells, organoids, in vivo) to investigate its effect on pancreatic cancer and analyzed the role of immune microenvironment changes in it through high-throughput sequencing. ResultsThe adv-MCK system is an oncolytic adenovirus system expressing three special components of genes. The microRNA (miRNA) targets (miRTs) enable adv-MCK to selectively replicate in pancreatic cancer cells. Catalase catalyzes the overexpressed hydrogen peroxide in pancreatic cancer cells to generate endogenous oxygen, which is catalyzed by killerRed to generate singlet oxygen (1O2) and further to enhance the oncolytic effect. Meanwhile, the adv-MCK system can specifically improve hypoxia in pancreatic cancer, exert antitumor effects in combination with photodynamic therapy, and activate antitumor immunity, especially by increasing the level of γδ T cells in the tumor microenvironment. ConclusionThe responsive oxygen-self-supplying adv-MCK cascade reaction system combined with photodynamic therapy can improve the hypoxic microenvironment of pancreatic cancer and enhance antitumor immunity, which provides a promising alternative treatment strategy for pancreatic cancer.

Identification and Analysis of Immune Microenvironment-Related Genes for Keloid Risk Prediction and Their Effects on Keloid Proliferation and Migration.

Keloid is a kind of proliferative scar with continuous growth, no restriction and easy recurrence, which cannot be cured and bring serious physical injury and psychological burden to patients. The main reason is that the pathological mechanism is not clear. Therefore, this project is expected to reveal the immune microenvironment-related genes and their functions in keloid progression, and provide effective targets for the treatment of keloid. Firstly, 8 kinds of immune infiltrating cells and 19 potential characteristic genes were identified by immune infiltration analysis, ssGSEA, LASSO regression (glmnet algorithm and lars algorithm) and WGCNA, indicating that keloid was closely related to the changes of immune microenvironment. Then, 4 pathological biomarkers of keloid (MAPK1, PTPRC, STAT3 and IL1R1) were identified by differentially analysis, univariate analysis, LASSO regression (lars algorithm), support vector machine recursive feature elimination (SVM-REF) algorithm, multivariate logical regression analysis and six machine learning algorithms. Based on the 4 feature genes, the risk prediction model and nomogram were constructed. Calibration curve and ROC analysis (AUC = 0.930) showed that the model had reliable clinical value. Subsequently, consistent cluster analysis was used to find that there were 2 immune microenvironment subsets in keloid patients, of which subgroup II was immune subgroup. Multiple independent datasets and RT-qPCR showed that the expression trend of the 4 genes was consistent with the analysis. Cell gain-loss experiment confirmed that 4 genes regulated the proliferation and migration of keloid cells. The above data shows that MAPK1, PTPRC, STAT3 and IL1R1 may be personalized therapeutic targets for keloid patients.

Sustained Liver HBsAg Loss and Clonal T- and B-Cell Expansion upon Therapeutic DNA Vaccination Require Low HBsAg Levels.

Suppression of HBV DNA, inhibition of HBV surface (HBsAg) production and therapeutic vaccination to reverse HBV-specific T-cell exhaustion in chronic HBV patients are likely required to achieve a functional cure. In the AAV-HBV mouse model, therapeutic vaccination can be effective in clearing HBV when HBsAg levels are low. Using a single-cell approach, we investigated the liver immune environment with different levels of HBsAg and sustained HBsAg loss through treatment with a GalNAc-HBV-siRNA followed by therapeutic vaccination. AAV-HBV-transduced C57BL/6 mice were treated with GalNAc-HBV-siRNA to lower HBsAg levels and then vaccinated using a DNA vaccine. We used single-cell RNA and V(D)J sequencing to understand liver immune microenvironment changes. GalNAc-HBV-siRNA, followed by therapeutic vaccination, achieved sustained HBsAg loss in all mice. This was accompanied by CD4 follicular helper T-cell induction, polyclonal activation of CD8 T cells and clonal expansion of plasma cells that were responsible for antibody production. This study provides novel insights into liver immune changes at the single-cell level, highlighting the correlation between induced reduction of HBsAg levels and clonal expansion of CD4, CD8 T cells and plasma cells in the liver upon HBV siRNA and subsequent therapeutic vaccination.

Abstract B037: A pharmacodynamic pilot study of DS8201a in patients with HER2 expressing advanced solid tumors

Abstract Background: DS-8201a (Trastuzumab (T) deruxtecan(D)) is an antibody-drug conjugate consisting of the HER2-targeting antibody T covalently bound via a lysosomal protease-cleavable linker to the novel topoisomerase 1 (Top1) inhibitor D with activity in tumors with low HER2 IHC scores of 1+ or 2+. The primary purpose of this study is to investigate the pharmacodynamic (PD) mechanisms underlying the activity of DS-8201a in advanced solid tumors, including those with low HER2 expression. Methods: This multicenter pilot study enrolled patients (pts) with advanced solid tumors expressing HER2 as defined by CLIA-certified labs i.e., a HER2 IHC score of 1+ or greater or ERBB2 amplifications (amp) or mutations (mut). DS-8201a was administered at 5.4 mg/kg intravenously once every 3 weeks, in 21-day cycles (C). PD biomarkers of Top1 target engagement by D payload, consequent DNA damage and repair (DDR), and immune microenvironment changes were analyzed in mandatory tumor biopsies collected at baseline, post-dose C1 and pre-dose C3. Blood samples for biomarker analyses were taken at several time points. Safety and overall response were also evaluated. Results: As of June 16, 2023, a total of 48 pts have been enrolled with diverse HER2 status distribution: 11 IHC 1+, 20 IHC 2+, 6 IHC 3+, 7 ERBB2 amp, 3 ERBB2 mut, and 1 with both IHC 1+ and ERBB2 amp. Median number of prior lines of systemic therapy was 3.5 (range 1-13) and 11 pts received prior Top1 inhibitor therapy. Grade (Gr) 3 or higher treatment-related adverse events (trAEs) were reported in 12 pts (25%). The most common Gr3/4 trAEs were myelosuppression. There were 7 pts (15%) with Gr2 and 1 pt (2%) with Gr3 pneumonitis. One pt with Gr2 pneumonitis was retreated after trAE resolution with steroid therapy and continued for another 9 Cs prior to progression. Of the evaluable patients, 1 pt (2%) had complete response (cervical, HER2 2+), 6 pts (13%) had confirmed partial response (PR) (uterine, 2+; ovarian, 2+; bladder, ERBB2 mut; uterine carcinosarcoma, 2+; 2 head and neck cancers, 1+ and 2+), 4 pts (8%) had unconfirmed PR (breast, 1+; extramammary Paget’s disease, 2+; pancreas, ERBB2 amp; uterine, 2+), and 17 pts (35%) had stable disease as their best response. Median progression free survival was 3.4 months (range 0.5-17.2). Top1 target engagement and induction of nuclear biomarkers of DDR (RAD51, pNBS1) were observed in more than half of the paired biopsies tested to date. DDR biomarker response was associated with both HER2 1+ and 2+ status. PD analyses are currently ongoing. Conclusion: DS-8201a demonstrated responses in various tumor types outside of breast cancer with HER2 low/ERBB2 alteration status. Preliminary PD data demonstrated expected Top1 target engagement and DDR induction, the extent of which is possibly independent of the degree of HER 2 staining. Analyses are currently underway to further define the effect of DS-8201a in advanced solid tumors. Citation Format: Sarah J Shin, Geraldine O'Sullivan-Coyne, Elizabeth K Lee, Arjun Mittra, Cora N Sternberg, Mary Jane Ong, Deborah Wilsker, Katherine Ferry-Galow, Jared Foster, Lamin Juwara, Naoko Takebe, Cheryl A Pickett, Ralph Parchment, James Doroshow, Alice Chen. A pharmacodynamic pilot study of DS8201a in patients with HER2 expressing advanced solid tumors [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr B037.

Single-Cell RNA Sequencing Reveals Contradictory Immune Microenvironment in Hemophagocytic Syndrome

Hemophagocytic lymphohistiocytosis (HLH), a formidable and rare clinical syndrome impacting multiple organs, manifests as a perilous condition. However, the intricate pathophysiological mechanisms underlying HLH remain yet to be fully elucidated. In this study, we obtained peripheral blood samples from 9 HLH patients spanning the years 2018 to 2022. Employing single-cell RNA sequencing (scRNA-seq), we conducted a comprehensive analysis of the alterations in the immune microenvironment, delving into the role of EBV infection in HLH and its influence on pathogenesis. By comparing with health donor peripheral blood , we identified a total of 11 significant immune cell populations among 72,779 single-cell transcriptomes, comprising 20,337 cells from healthy controls and 52,442 cells from HLH patients. Notably, we found that the proportion of T cells increased significantly, and other immune cells decreased in HLH patients. In terms of function, we found that the overall T cell killing ability was weakened, and the factor secretion ability was enhanced. Concerning myeloid cells, the impact of CD16+ monocytes on T cells exhibited a pronounced increase, along with an enhanced ability to secrete IL-18 factors, potentially serving as the main source of cells promoting T cell function. Different subpopulations of T cells have significant changes in the pathogenesis of HLH. Remarkably, both CD4+ T cells and CD8+ T cells exhibited HLA-DR+GZMK+ cell subgroups with upregulated IFN-γ production and response, suggesting their association with the hyperinflammatory state in HLH. A correlation analysis between the proportion of HLA-DRA+ GZMK+ T cells and the severity score revealed a significant correlation (p<0.05), with the ROC curve further affirming their predictability in assessing high inflammatory activity. Among CD4+ T cells, the proportion of Treg cells and the secretion of inhibitory factors such as TGFb1 decreased. Additionally, we noted the presence of a functionally impaired subset of CBLB+CD8+ T cells, indicating the considerable variability in T cell subset functionality in HLH. Next, a comprehensive analysis of the alterations in myeloid cells, B cells, and NK cells in HLH patients was conducted. We observed a substantial reduction in the number of DC cells and immune-related functions within various myeloid cell subsets. Regarding B cells, an increase in anergy B cells was observed, whereas the population of plasma cells, an effective B cell type, exhibited a decrease. In the context of NK cells, there was a significant increase in the proportion of NK cell subsets associated with IFN-γ secretion. Moreover, EBV-infected T cells in EBV-associated HLH were identified as the principal source of IFN-γ. Through single-cell EBV-CALL analysis, we found that IFN-γ secretion was primarily attributed to EBV-infected T cells, subsequently influencing CD16+ monocytes. Additionally, IL-16 production was predominantly observed in EBV-infected CD16+ monocytes, thereby impacting lymphocytes. Moreover, Monocytes were stimulated by EBV-infected CD4+ T cells and Atypical T cells, leading to the secretion of a pro-inflammatory factors such as MIF. Furthermore, our investigation unveiled that EBNA2 could promote MYC into the nucleus and enhance the proliferation and IFN-γ secretion of T cells. In conclusion, our comprehensive analysis of the immune microenvironment changes following the onset of HLH has yielded valuable insights and novel perspectives for understanding the underlying mechanisms and potential clinical treatments of this condition.

Single-cell transcriptome analysis of liver immune microenvironment changes induced by microplastics in mice with non-alcoholic fatty liver

Recent studies have discovered that tiny particles of microplastics (MPs) at the nano-scale level can enter the body of organisms from the environment, potentially causing metabolic ailments. However, further investigation is required to understand the alterations in the immune microenvironment associated with non-alcoholic fatty liver disease (NAFLD) occurrence following exposure to MPs.Experiments were performed using mice, which were given a normal chow or high-fat diet (NCD or HFD, respectively) plus free drinking of sterile water with or without MPs, respectively. Employing an impartial technique known as unbiased single-cell RNA-sequencing (scRNA-seq), the cellular (single-cell) pathology landscape of NAFLD and related changes in the identified immune cell populations induced following MPs plus HFD treatment were assessed. The results showed that mice in the HFD groups had remarkably greater NAFLD activity scores than those from the NCD groups. Moreover, administration of MPs plus HFD further worsened the histopathological changes in the mice's liver, leading to hepatic steatosis, inflammatory cell infiltrations and ballooning degeneration. Following the construction of a sing-cell resolution transcriptomic atlas of 43,480 cells in the mice's livers of the indicated groups, clear cellular heterogeneity and potential cell-to-cell cross-talk could be observed. Specifically, we observed that MPs exacerbated the pro-inflammatory response and influenced the stemness of hepatocytes during HFD feeding. Importantly, treatment with MPs significantly increase the infiltration of the infiltrating liver-protecting Vsig4+ macrophages in the liver of the NAFLD mouse model while remarkably decreasing the angiogenic S100A6+ macrophage subpopulation. Furthermore, mice treated with MPs plus HFD exhibited significantly increased recruitment of CD4+ cells and heightened exhaustion of CD8+ T cells than those from the control group, characteristics typically associated with the dysregulation of immune homeostasis and severe inflammatory damage. Overall, this study offers valuable perspectives into comprehending the potential underlying cellular mechanisms and regulatory aspects of the microenvironment regarding MPs in the development of NAFLD.

A Macrophage-Related Gene Signature for Identifying COPD Based on Bioinformatics and ex vivo Experiments.

This study aims to investigate the association between immune cells and the development of COPD, while providing a new method for the diagnosis of COPD according to the changes in immune microenvironment. In this study, the "CIBERSORT" algorithm was used to estimate the tissue infiltration of 22 types of immune cells in GSE20257 and GSE10006. The "limma" package was used for differentially expressed analysis. The key modules associated with vital immune cells were identified using WGCNA. GO and KEGG enrichment analysis revealed the biological functions of the candidate genes. Ultimately, a novel diagnostic prediction model was constructed via machine learning methods and multivariate logistic regression analysis based on GSE20257. Furthermore, we examined the stability of the model on one internal test set (GSE10006), three external test sets (GSE8545, GSE57148 and GSE76925), one single-cell transcriptome dataset (GSE167295), macrophages (THP-M cells) and lung tissue from COPD patients. M0 macrophages (AUC > 0.7 in GSE20257 and GSE10006) were considered as the most important immune cells through exploring the immune microenvironment landscapes in COPD patients and healthy controls. The differentially expressed genes from GSE20257 and GSE10006 were divided into six and five modules via WGCNA, respectively. The green module in GSE20257 (cor = 0.41, P < 0.001) and the brown module in GSE10006 (cor = 0.67, P < 0.001) were highly correlated with M0 macrophages and were selected as key modules. Forty-one intersected genes obtained from two modules were primarily involved in regulation of cytokine production, regulation of innate immune response, specific granule, phagosome, lysosome, ferroptosis, and other biological processes. On the basis of the candidate genetic markers further characterized via the "Boruta" and "LASSO" algorithm for COPD, a diagnostic model comprising CLEC5A, FTL and SLC2A3 was constructed, which could accurately distinguish COPD patients from healthy controls in multiple datasets. GSE20257 as the training set has an AUC of 0.916. The AUCs of the internal test set and three external test sets were 0.873, 0.932, 0.675 and 0.688, respectively. Single-cell sequencing analysis suggested that CLEC5A, FTL and SLC2A3 were expressed in macrophages from COPD patients. The expressions of CLEC5A, FTL and SLC2A3 were up-regulated in THP-M cells and lung tissue from COPD patients. According to the variations of immune microenvironment in COPD patients, we constructed and validated a novel macrophage M0-associated diagnostic model with satisfactory predictive value. CLEC5A, FTL and SLC2A3 are expected to be promising targets of immunotherapy in COPD.

Changes of immune microenvironment in head and neck squamous cell carcinoma in 3D-4-culture compared to 2D-4-culture

BackgroundThe immune system plays a crucial role in initiating, progressing, and disseminating HNSCC. This study aims to investigate the differences in immune microenvironments between 2D-4-culture and 3D-4-culture models of head and neck squamous cell carcinoma (HNSCC) cells (FaDu), human fibroblasts (HF), human monocytes (THP-1), and human endothelial cells (HUVEC).MethodsFor the 3D-4-culture model, FaDu:HF:THP-1 (2:1:1) were inoculated in an ultra-low attachment culture plate, while HUVECs were placed in a transwell chamber. The ordinary culture plate was used for the 2D-4-culture model. Tumor-associated macrophage markers (CD163), tumor-associated fibroblast markers (FAP), and epithelial-mesenchymal transition (EMT) were detected by western blot. Inflammatory cytokines (IL-4, IL-2, CXCL 10, IL-1 β, TNF-α, CCL 2, IL-17 A, IL-6, IL-10, IFN-γ, IL-12 p 70, CXCL 8, TGFβ1) in the supernatant were measured by flow cytometry. HUVEC migration was observed under a microscope. The 3D spheres were stained and observed with a confocal microscope. CCK8 assay was used to detect the resistance of mixed cells to cisplatin in both 2D-4-culture and 3D-4-culture.ResultsAfter three days of co-culture, the 3D-4-culture model showed increased expression levels of CD163 and FAP proteins (both P < 0.001), increased expression of E-cadherin protein and N-cadherin protein expression (P < 0.001), decreased expression of vimentin (P < 0.01) and Twist protein (P < 0.001). HUVEC migration significantly increased (P < 0.001), as did the concentrations of IP-10, MCP-1, IL-6, and IL-8 (all P < 0.001). Confocal microscopy showed that 3D-4-culture formed loose cell clusters on day 1, which gradually became a dense sphere surrounded by FaDu cells invading the inside. After co-culturing for 24 h, 48 h, and 72 h, the resistance of mix cells to cisplatin in 3D-4-culture was significantly higher than in 2D-4-culture (P < 0.01 for all).ConclusionCompared to 2D-4-culture, 3D-4-culture better simulates the in vivo immune microenvironment of HNSCC by promoting fibroblast transformation into tumor-associated fibroblasts, monocyte transformation into tumor-associated macrophages, enhancing endothelial cell migration ability, partial EMT formation in HNSCC cells, and is more suitable for studying the immunosuppressive microenvironment of HNSCC.Graphical abstract

Exploring Psoriasis Inflammatory Microenvironment by NanoString Technologies.

Psoriasis is a chronic inflammatory skin disease whose molecular mechanisms and microenvironment are poorly understood. We performed gene expression analysis through the nCounter® PanCancer Immune Profiling Panel (NanoString Technologies, Seattle, WA, USA) on 22 FFPE punch biopsies from 19 psoriasis-affected patients. A subset of five cases was analyzed before (T0) and after 6 months (T6) of treatment with dimethyl fumarate (DMF) to address immune microenvironment changes. Molecular comparisons according to biopsy site and age of onset showed a different distribution of innate immune cells (mast cells, macrophages, NK cells, and DC cells) and pathways (complement regulation and transporter functions). The analysis according to PASI (Psoriasis Area and Severity Index) led to non-significant results, suggesting no link between molecular expression profile and clinical amount of skin disease. In DMF-treated patients, we observed a strong immunomodulatory effect after treatment: A subversion of exhausted CD8 T cells, NK CD56dim cells, Tregs, neutrophils, CD45+ cells, T cells, B cells, and macrophages was reported between the two analyzed time-points, as well as the reduction in pro-inflammatory pathways and molecules, including cytotoxicity, pathogen defense, antigen processing, adhesion, cell cycle, chemokines, cytokines, and interleukins. The inflammatory psoriatic microenvironment can be modulated using DMF with encouraging results, achieving an immune-tolerant and non-inflammatory condition through the regulation of both innate and adaptive immunity.