Immune Cells In Tumor Microenvironment Research Articles

Abstract 3644: Uncover spatial signatures of tumor microenvironment and oncogenic pathways using 6,000-plex single-cell spatial molecular imaging on FFPE skin squamous cell carcinoma

Abstract Background: Tumor progression and therapeutic response are regulated by the tumor microenvironment. Understanding the spatial association and architecture of molecular characteristics and composition of tumor immune microenvironment at single-cell and subcellular resolution encourages improvements in clinical prognosis and immunotherapy benefits. Single-cell Spatial profiling technologies permit the study of transcriptional activity at the spatial, single-cell level and provide abundant, high-resolution information required for the identification of clinical-related features in immuno-oncology. Methods: We performed an ultra-high-plex RNA assay to detect 6,000 targets simultaneously in situ on FFPE human skin squamous cell carcinoma using the CosMx™ Spatial Molecular Imager (SMI). For the selection of regions of interest, four protein markers and DAPI were co-detected on the same tissue slide. Tertiary analysis algorithms were developed for cell typing, co-localization of genes and ligands, cell-cell interaction, and pathway analysis. Results: Thousands of transcripts were simultaneously detected with high sensitivity and specificity on the FFPE skin squamous cell carcinoma tissue section at single-cell subcellular resolution. We investigated the tumor microenvironment including cell types, their spatial distribution and proportion of diversified immune cells in the tumor compartment. The cell typing results revealed many cancerous subpopulations, which resolved spatially from cells that lacked any defining marker genes. We also assessed distances between immune cells and their nearest functional-related neighbors. Moreover, we revealed the ligands co-localization, as well as spatial patterns of direct cell-cell interactions and signaling pathways. We found that some genes have elevated expression in macrophages which are near cancer compared to those are far from cancer cells, empowering the molecular investigation of novel signaling between immune and cancer cells in tumor immune microenvironment. Conclusions: Single-cell spatial measurements of 6,000 RNA and four proteins on the same tissue section, along with a large viewing area on archival FFPE tissue, provide a novel tool to reveal the spatial signature of tumor microenvironment and oncogenic pathways, facilitating the next level of cancer and therapeutic research. FOR RESEARCH USE ONLY. Not for use in diagnostic procedures. FOR RESEARCH USE ONLY. Not for use in diagnostic procedures. Citation Format: Michael Patrick, Shanshan He, Saskia Ilcisin, David Kroeppler, Patrick Danaher, Jason Reeves, Mark Gregory, Haiyan Zhai, Michael Rhodes, Joseph Beechem. Uncover spatial signatures of tumor microenvironment and oncogenic pathways using 6,000-plex single-cell spatial molecular imaging on FFPE skin squamous cell carcinoma [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 3644.

Abstract 2688: Age-associated changes in macrophage function and phenotype affects cancer development, and the efficacy of macrophage targeted anticancer therapies in murine melanoma model

Abstract Introduction: Aging of the immune system is a critical risk factor for chronic diseases, including cancer. Globally, cancer incidence is higher between 45 to 75 years of age and declines thereafter. However, the implications of aging in cancer are understudied, and aged populations are underrepresented, both in preclinical and clinical studies. The role of macrophages in cancer progression has gained attention as a tool and target for anticancer therapies. Tumor-associated macrophages (TAMs) mainly exhibit an anti-inflammatory M2 phenotype, promote an immunosuppressive tumor microenvironment (TME), and contribute to developing resistance against immunotherapies. Therefore, several strategies targeting the phenotype and function of TAMs are being explored, including inhibitors of histone deacetylases (HDACis), adoptive macrophage cell therapy, and CAR macrophages. Studies from our group have shown that ultra-specific HDAC6is can switch macrophages from anti-inflammatory, M2, to pro-inflammatory and antitumoral M1 phenotype with minimal cytotoxicity to cancer cells. However, it is unknown if age-related changes in macrophages affect such therapeutic strategies and the TME. Objective: To characterize the changes in macrophage function and phenotype with aging and study its implications on the TME and the efficacy of macrophage-based anticancer therapies. Methods: Wildtype mice of ages 6-8 WKS, 3-6 MO, 10-12 MO, and 20-24 MO were injected with SM1 melanoma cells to study tumor growth kinetics. Bone marrow-derived macrophages (BMDMs) isolated from tumor-bearing and healthy mice were polarized to M1 and M2 phenotype treated with HDAC6i to study age-associated changes in phagocytic activity, antigen presentation, and gene expression. Pathways associated with macrophage polarization were examined by flow cytometry, qRT-PCR, western blot, and single-cell proteomics. Immune cells in TME were characterized in flow cytometry and single-cell RNA and secretome analyses. Results: Tumor growth in SM1 murine melanoma model was significantly slower in older mice when compared to younger mice. Aged macrophages demonstrated significant defect in polarization to M1 and M2 phenotypes that was more pronounced in BMDMs from tumor-bearing mice. Tumor-associated macrophages showed inefficient monocyte-to-macrophage transition, as also reflected in the single-cell secretome analysis. The ability of HDAC6i to enhance macrophage function was reduced among older mice. Conclusions: The functional and phenotypic characteristics of macrophages change with age and can significantly affect tumor growth and the effectiveness of macrophage-targeted anticancer therapies. Our study highlights the importance of studying aging in macrophages and better representation of aged populations in preclinical and clinical studies. Citation Format: Manasa Suresh, Xintang Li, Satish Noonepalle, Nithya Gajendran, Marie Durr, David Quiceno-Torres, Karen Tan, Alejandro Villagra. Age-associated changes in macrophage function and phenotype affects cancer development, and the efficacy of macrophage targeted anticancer therapies in murine melanoma model [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 2688.

Abstract 1790: Pyruvate carboxylase regulates tumor progression through central carbon metabolism and immunosuppression

Abstract The tumor microenvironment (TME) is characterized by metabolic reprogramming and immune evasion, essential features in tumor progression. Tumor metabolic dysregulation, particularly the high production of lactate, plays a pivotal role in suppressing antitumor immunity within the TME. Pyruvate carboxylase (PC), responsible for converting pyruvate to oxaloacetate, is a critical determinant for lung metastasis in triple-negative breast cancer (TNBC). Herein we test the hypothesis that PC-mediated regulation of central carbon metabolism controls TME immunosurrveilance. Wild-type C57BL6/J and NSG mice received orthotopic injections of E0771 or M-Wnt tumor cells with shRNA targeting PC or a scramble control. RNA from tumors underwent transcriptomic profiling using Affymetrix Clariom D microarray (n=3-6/group per experiment). Gene set enrichment analysis identified pathways enriched in each condition, including a PC-associated hypoxia signature. Immunohistochemistry with anti-CD3 antibody and full spectrum flow cytometry assessed T cell infiltration and TME immune cell composition. Untargeted metabolomics, extracellular flux analysis, and high-resolution respirometry determined how loss of PC altered cellular metabolism. We found that suppressing PC expression increased primary tumor growth (~2 fold), potently drove immunosuppression, and remodeled cellular metabolism towards lactate production. Injection of PC-suppressed cells increased regulatory T cell levels in wild type mice. Importantly, PC-suppressed cells injected into NSG mice, which lack T, B, and NK cells, demonstrated slower, rather than accelerated, tumor growth. PC-suppression reduced oxygen consumption rate (OCR), but supply of anaplerotic carbon through exogenous malate or oxaloacetate restored OCR. Conversely, both the rate of and reliance on lactate production was increased by PC suppression. Notably, loss of immunosurveillance following downregulation of PC was reversed by inhibiting lactate transport. Additionally, lower PC expression was associated with increased hypoxia in tumors, supporting in vitro evidence of PC-repression by hypoxia. In summary, hypoxia-induced PC suppression emerges as a crucial mechanism through which primary tumors hinder antitumor immunity, partly via increased lactate production. These findings underscore the significance of PC-directed tumor metabolism as an understudied nexus in the interplay between tumor progression and antitumor immunity. Citation Format: Michael F. Coleman, Eylem Kulkoyluoglu Cotul, Alexander J. Pfeil, Alyssa N. Ho, Emily N. Devericks, Muhammad H. Safdar, Hao Chen, Numair Attaar, Violet A. Kiesel, Dorothy Teegarden, Stephen D. Hursting, Michael K. Wendt. Pyruvate carboxylase regulates tumor progression through central carbon metabolism and immunosuppression [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 1790.

Abstract 5617: Combined inhibition of ATR and ATM with tuvusertib and lartesertib (M4076) impacts the tumor microenvironment

Abstract Ataxia telangiectasia and Rad3-related protein (ATR) and ataxia telangiectasia mutated (ATM) are two of the main kinases of the DNA damage response (DDR). Recent work has demonstrated that the addition of ATM inhibitors enhances the cytotoxicity and in vivo anti-tumor efficacy of ATR inhibitors by abrogating the ATR inhibitor mediated G1 cell cycle arrest and enhancing chromosomal damage.1 Prior to causing cell death, damaged chromosome fragments can end up in the cytosol where they are detected by cytosolic nucleic acid sensors such as cGAS, resulting in the induction of inflammatory signaling pathways and an anti-tumor immune response. This suggests that the mode of action of DDR inhibitors may involve the tumor microenvironment (TME). We therefore aimed to assess the influence of combined pharmacological ATR and ATM inhibition on the TME to better understand how this could be exploited therapeutically. In line with published results in human tumor models, the treatment of murine colon cancer MC-38 cells in vitro with a combination of ATR inhibitor tuvusertib and ATM inhibitor lartesertib led to cell death. Further analysis revealed an activation of the cGAS-STING signaling pathway, an upregulation of PD-L1 and the release of inflammatory cytokines. These results confirmed the activation of immune signaling pathways upon combined inhibition of ATR and ATM. To analyze the stimulation of an anti-tumor immune response upon tuvusertib + lartesertib treatment in vivo, MC-38 cells were transplanted into immunocompetent C57BL/6J mice. Immunoprofiling by flow cytometry and immunohistochemistry staining confirmed that treatment with tuvusertib + lartesertib indeed altered the TME in this setting. In line with the in vitro findings, a significant upregulation of PD-L1 on immune and tumor cells could be observed after 24, 48, and 72 h of treatment even though MC-38 cells expressed high levels of PD-L1 already. Immunoprofiling did not reveal any changes in the TME immune cell content at these early time points. Interestingly, PD-L1 expression as well as tumor immune population changed after prolonged (23 days) treatment. PD-L1 was still expressed on tumor cells but to a significantly lesser extent and a depletion of CD8+ T-cells was observed. However, a significant increase in NK cells could be detected. In summary, we show that inhibition of the DDR through a combination of ATR and ATM inhibitors influences the TME in the MC-38 tumor model. These findings suggest an additional mode of action beyond direct cancer cell cytotoxicity. Further studies on how this may be leveraged therapeutically, for example through a combination with immune checkpoint inhibitors, are warranted. 1. Turchick A, Zimmermann A, et al. Mol Cancer Ther 2023;22(7):859-872. Citation Format: Karin Laaber, Audrey Turchick, Julia Jabs, Brian Elenbaas, Lyubomir T. Vassilev, Astrid Zimmermann. Combined inhibition of ATR and ATM with tuvusertib and lartesertib (M4076) impacts the tumor microenvironment [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 5617.

Spatial relationships in the urothelial and head and neck tumor microenvironment predict response to combination immune checkpoint inhibitors

Immune checkpoint inhibitors (ICI) can achieve remarkable responses in urothelial cancer (UC), which may depend on tumor microenvironment (TME) characteristics. However, the relationship between the TME, usually characterized by immune cell density, and response to ICI is unclear. Here, we quantify the TME immune cell densities and spatial relationships (SRs) of 24 baseline UC samples, obtained before pre-operative combination ICI treatment, using multiplex immunofluorescence. We describe SRs by approximating the first nearest-neighbor distance distribution with a Weibull distribution and evaluate the association between TME metrics and ipilimumab+nivolumab response. Immune cell density does not discriminate between response groups. However, the Weibull SR metrics of CD8+ T cells or macrophages to their closest cancer cell positively associate with response. CD8+ T cells close to B cells are characteristic of non-response. We validate our SR response associations in a combination ICI cohort of head and neck tumors. Our data confirm that SRs, in contrast to density metrics, are strong biomarkers of response to pre-operative combination ICIs.

PDE5 inhibitors against cancer via mediating immune cells in tumor microenvironment: AI‐based approach for future drug repurposing exploration

AbstractPhosphodiesterase‐5 (PDE5) inhibitors are used clinically for the treatment of erectile dysfunction, pulmonary arterial hypertension, and other urological diseases. Emerging evidences have suggested the therapeutic capacity of PDE5 inhibitors as the repurposed drugs in oncology. However, the essential immune function of PDE5 inhibitors against cancer in tumor microenvironment (TME) remains unclear. This review aimed to summarize the recent advances regarding the repurposing of PDE5 inhibitors as anti‐cancer agents for cancer management to enhance the anti‐tumor immune response by mediating various immune cells, which included the myeloid‐derived suppressor cells, macrophages, T cells, fibroblasts, and natural killer cells in TME. Moreover, artificial intelligence (AI), as a new approach, is composed of traditional machine learning and deep learning methods and could be potentially used to identify the targets of immune cells in TME and predict the efficacy for repurposed drug toward malignancies. In summary, these endeavors provide novel insights into the comprehensive strategies for PDE5 inhibitors mediating immune cells against cancer and AI‐based approach for future drug repurposing exploration.

PD-L1 Expression and Tumour Microenvironment Patterns in Resected Non-Small-Cell Lung Cancer.

Background and Objectives: Although perioperative immunotherapy is implemented as a standard of care for resected non-small cell lung cancer (NSCLC), there is unmet need for predictive biomarkers as programmed death-ligand 1 (PD-L1) is not the perfect one. The functionality of tumour-infiltrating immune cells in the tumour microenvironment (TME) and the involvement in immune system response is one of the crucial factors that lead to pro- or anti-tumourigenic role and could predict response to PD-1 and PD-L1 inhibitors. So, the investigation of PD-L1 expression in the context of TME in early stages of resected NSCLC is urgent required. Materials and Methods: PD-L1 expression by three scoring methods: tumour proportion score (TPS), immune cell score (IC), and combined proportion score (CPS) was assessed in 72 archival tumour tissue specimens from stage I-III surgically resected NSCLC patients and associations with immune cells in TME were explored. Results: PD-L1 expression ≥1% evaluated by TPS, IC, and CPS was detected in 28%, 36%, and 39% of cases and moderate, substantial, and strong agreement between TPS and IC, TPS and CPS, CPS and IC was detected (Cohen's κ coefficient 0.556, 0.63, and 0.941, respectively). PD-L1 TPS, IC, and CPS correlated with smoking intensity defined as pack-years (r = 0.0305, p = 0.012; r = 0.305, p = 0.013, and r = 0.378, p = 0.002, respectively). Only PD-L1 TPS was associated with squamous cell carcinoma (p = 0.028). PD-L1 IC ≥1% was more often seen in tumours with high CD4+ T cells infiltration (p = 0.02), while PD-L1 CPS ≥1%-in tumours with high CD4+ and CD8+ T cells infiltration (p = 0.021 and p = 0.048, respectively). PD-L1 IC and CPS ≥10% was more often detected in tumours with greater number of tumour-infiltrating CD4+Foxp3+ T cells (p = 0.01 and p = 0.025, respectively). PD-L1 TPS ≥50% was associated with higher probability to detect greater number of tumour-infiltrating M2 macrophages (p = 0.021). No association was found between PD-L1 alone or in combination with tumour-infiltrating lymphocytes, macrophages, and disease-free or overall survival. Conclusions: This study results revealed that rates of PD-L1 expression correlated among three scoring methods (TPS, IC, and CPS). Moreover, PD-L1 expression was significantly associated with smoking intensity, squamous histology, and tumour-infiltrating immune cells.

COL10A1 as a Prognostic Biomarker in Association with Immune Infiltration in Prostate Cancer.

The collagen type X alpha 1 (COL10A1) has recently been found to play an important role in the development and progression of cancer. However, the link between COL10A1 and the tumor immune microenvironment remains understood scantily. In the current study, the pan-cancer data of The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) were used to investigate the expression mode, the clinical prognostic and diagnostic value of COL10A1 in different tumors. We used TCGA data to assess the correlations between COL10A1 and clinical symptoms of prostate cancer. The R packages "edgR" and "clusterProfiler" were used for differential expression gene and enrichment analysis of COL10A1. Immunohistochemistry was further employed to corroborate the expression of COL10A1 gene in prostate cancer. After that, we used TIMER to evaluate the pertinence of COL10A1 expression to immune infiltration level in prostate cancer. On the whole, COL10A1 was expressed at significantly higher levels in a variety of tumor tissues than in the corresponding normal tissues. Besides, significant correlations with tumor prognosis and relative exactitude in predicting tumors show that COL10A1 may be a probable prognostic and diagnostic biomarker of prostate cancer. In addition, the evidence indicates a significant correlation between COL10A1 and clinical symptoms of prostate cancer. Furthermore, the main molecular functions of COL10A1 included humoral immune response, complement activation, immunoglobulin, regulation of complement activation, and regulation of humoral immune response. Finally, we found that COL10A1 expression is positively correlated with enhanced macrophage and M2 macrophage infiltration in prostate cancer. The study indicates that COL10A1 might participate in M2 macrophage polarization in prostate cancer. COL10A1 might be an innovative biomarker to evaluate tumor microenvironment immune cell infiltration and prognosis in prostate cancer.

Tumorous IRE1α facilitates CD8+T cells-dependent anti-tumor immunity and improves immunotherapy efficacy in melanoma

BackgroundTumor cells frequently suffer from endoplasmic reticulum (ER) stress. Previous studies have extensively elucidated the role of tumorous unfolded protein response in melanoma cells, whereas the effect on tumor immunology and the underlying mechanism remain elusive.MethodsBioinformatics, biochemical assays and pre-clinical mice model were employed to demonstrate the role of tumorous inositol-requiring transmembrane kinase/endoribonuclease 1α (IRE1α) in anti-tumor immunity and the underlying mechanism.ResultsWe firstly found that IRE1α signaling activation was positively associated with the feature of tumor-infiltrating lymphocytes. Then, pharmacological ER stress induction by HA15 exerted prominent anti-tumor effect in immunocompetent mice and was highly dependent on CD8+T cells, paralleled with the reshape of immune cells in tumor microenvironment via tumorous IRE1α-XBP1 signal. Subsequently, tumorous IRE1α facilitated the expression and secretion of multiple chemokines and cytokines via XBP1-NF-κB axis, leading to increased infiltration and anti-tumor capacity of CD8+T cells. Ultimately, pharmacological induction of tumorous ER stress by HA15 brought potentiated therapeutic effect along with anti-PD-1 antibody on melanoma in vivo.ConclusionsTumorous IRE1α facilitates CD8+T cells-dependent anti-tumor immunity and improves immunotherapy efficacy by regulating chemokines and cytokines via XBP1-NF-κB axis. The combination of ER stress inducer and anti-PD-1 antibody could be promising for increasing the efficacy of melanoma immunotherapy.

LMTK3 gene expression and the molecular landscape of colorectal cancer (CRC).

172 Background: Lemur tail kinase 3 (LMTK3) plays a critical role in multiple cellular pathways such as Wnt signaling, KIT modulation, and the estrogen receptor pathway. We previously reported that LMTK3 gene polymorphisms are associated with clinical outcome in patients with CRC, and that LMTK3 and estrogen-mediated signaling play a crucial role in CRC tumorigenesis in vitro. Here, we aimed to characterize the molecular features associated with LMTK3 gene expression in CRC. Methods: 20,219 CRC were tested at Caris Life Sciences (Phoenix, AZ) with NextGen Sequencing on DNA (592 genes or WES) and RNA (WTS). Top quartile transcripts per million (TPM) for LMTK3 expression (Q4) were considered high while bottom quartile (Q1) low. Consensus molecular subtypes (CMS) were assessed using RNAseq. Cell infiltration (CI) in the tumor microenvironment (TME) was estimated by QuantiSEQ. X2 and Fisher-Exact tests were used, and significance was determined as p-value adjusted for multiple comparisons ( q < 0.05). Gene expression profiles were analyzed for transcriptional signatures predictive of response to immunotherapy (interferon gamma [IFNγ] score; T-cell inflamed signature [TIS] score). Results: LMTK3 expression was highest in left-sided (0.98 median TPM) followed by right-sided (0.96) and lowest in rectal tumors (0.92). No difference in patient sex distribution was observed between Q1 and Q4 cohorts. Overall, LMTK3 Q1 was associated with TMB-high (≥ 10 Mut/Mb, 11.4 vs 8.7%) and dMMR/MSI-H (8.1 vs 4.6%) ( q < 0.0001); however, these associations were no longer significant in pMMR/MSS tumors. In the pMMR/MSS cohort, LMTK3 expression was highest in CMS4 (1.09 median TPM) followed by CMS2 (0.98), CMS1 (0.88), and lowest in CMS3 (0.70, all intergroup q < 0.05). LMTK3 high showed differential rates of mutations and copy number alterations (CNA) in several genes, including higher mutation rates of APC, TP53, and CDX2 CNA, while lower mutation rates of KMT2A/D, ASXL1, ATM, SMAD4, RNF43 and AMER1 in the overall cohort ( q < 0.05). In the pMMR/MSS cohort, the associations with APC, TP53, SMAD4 and ATM mutations and CDX2 CNA still held true ( q < 0.05). High LMTK3 was associated with higher immune CI in the TME, including B cells, neutrophils, NK cells, CD4+ T cells, monocytes and dendritic cells, while macrophages and Tregs were lower regardless of tumor MSI status (fold change: 0.83-2.4, all q < 0.0001). The IFNγ score was significantly lower in LMTK3 Q4 while the TIS score was significantly higher in LMTK3 Q4 ( q < 0.0001). Conclusions: Our data show a strong association between LMTK3 gene expression and distinct molecular features and TME immune cell infiltration in CRC. These findings suggest that LMTK3 may be an important molecular factor that plays a role in determining the composition of the TME, thus targeting LMTK3 could represent a novel strategy in selected CRC subgroups.

Characterization of the cachexia pathway in pancreatic ductal adenocarcinoma.

699 Background: Cancer cachexia is characterized by progressive weight loss and skeletal muscle degradation, contributing to 33% of pancreatic ductal adenocarcinoma (PDAC) deaths. Targeting myostatin in the myostatin-activin pathway has been shown to reverse cachexia. Here, we present comprehensive clinical and molecular characterization of the myostatin-activin pathway in PDAC. Methods: 9,607 samples of PDAC tested at Caris Life Sciences (Phoenix, AZ) with WTS (Illumina NovaSeq) and NextGen DNA sequencing (NextSeq, 592 Genes and NovaSEQ, WES) were analyzed. Cachexia gene scores (GS) were calculated by averaging the positive z scores of activators and negative z scores of repressors in the myostatin-activin pathway. Activators were ACVR1B, ACVR1C, ACVR2A, ACVR2B, SMAD2, SMAD3, SMAD4, and TGFBR1, while repressors were SMAD1, SMAD5, SMAD6, SMAD7, SMURF1, and SMURF2. The top quartile (Q4) and bottom quartile (Q1) of GS were compared using chi-squared and Fisher-Exact tests. RNA deconvolution analysis with QuantiSEQ estimated cell infiltration in the tumor microenvironment (TME). Differences in overall survival (OS) were analyzed from insurance claims data and calculated from time of tissue collection using Kaplan-Meier estimates. Statistical significance was determined as a P-value adjusted for multiple comparisons ( q<0.05). Results: GS were higher in primary tumors compared to metastases (median: -0.71 vs -0.86, q<0.05). GS was associated with increased PD-L1 IHC expression (Q1 21.2% vs Q4 10.3%, q<0.001), but not TMB-high (1.9% vs 2.1%, q=1) or MSI-H status (1.1% vs 1.3%, q=1). GS correlated with increased expression of immune related genes ( CD274, CD80, IDO1, CD86, PDCD1, LAG3, CTLA4, HAVCR2, and IFNG, q<0.05). However, TME immune cell infiltration did not vary based on cachexia GS. Mutation rates of TP53 (Q1 79.4% vs Q4 73.7%), ARID1A (Q1 11.8% vs Q4 6.9%) and KRAS (Q1 92.7% vs Q4 86.4%) were associated with Q1-GS (all q<0.01), while STK11 mutations (1.1% vs 3.0%, q=0.001) were associated with Q4-GS. Spearman correlation linked cachexia GS with the lipid metabolizing genes UCP2 (rho=0.49) and UCP3 (rho=0.30), as well as the inflammatory markers CCL2/MCP-1(rho=0.34) and IL1B (rho=0.33). Decreased OS was seen with higher tumor expression of the myostatin-activin pathway activator, SMAD3 (6.6 vs 8.5 mo, HR=1.22, CI 1.12-1.33, P<0.001), and lower expression of the repressor SMAD7 (6.9 vs 8.9 mo, HR=0.91, CI 0.79-0.90, P=0.034) in metastatic PDAC. Conclusions: This is the largest molecular and clinical characterization of the myostatin-activin cachexia pathway in PDAC. Our data show that increased activation of the myostatin-activin pathway is associated with immune mediators, lipid metabolism, and inflammatory gene activation. Activators and repressors are significant predictors of survival in PDAC, suggesting possible novel therapeutic targets.

Systemic Delivery of Paclitaxel by Find-Me Nanoparticles Activates Antitumor Immunity and Eliminates Tumors.

Local delivery of immune-activating agents has shown promise in overcoming an immunosuppressive tumor microenvironment (TME) and stimulating antitumor immune responses in tumors. However, systemic therapy is ultimately needed to treat tumors that are not readily locatable or accessible. To enable systemic delivery of immune-activating agents, we employ poly(lactic-co-glycolide) (PLGA) nanoparticles (NPs) with a track record in systemic application. The surface of PLGA NPs is decorated with adenosine triphosphate (ATP), a damage-associated molecular pattern to recruit antigen-presenting cells (APCs). The ATP-conjugated PLGA NPs (NPpD-ATP) are loaded with paclitaxel (PTX), a chemotherapeutic agent inducing immunogenic cell death to generate tumor antigens in situ. We show that the NPpD-ATP retains ATP activity in hostile TME and provides a stable "find-me" signal to recruit APCs. Therefore, the PTX-loaded NPpD-ATP helps populate antitumor immune cells in TME and attenuate the growth of CT26 and B16F10 tumors better than a mixture of PTX-loaded NPpD and ATP. Combined with anti-PD-1 antibody, PTX-loaded NPpD-ATP achieves complete regression of CT26 tumors followed by antitumor immune memory. This study demonstrates the feasibility of systemic immunotherapy using a PLGA NP formulation that delivers ICD-inducing chemotherapy and an immunostimulatory signal.

Abstract B019: Tumor-derived PTHrP molds an immunosuppressive microenvironment

Abstract Purpose[JP1] : Molecular phenotyping of PDAC [PJ2] has revealed an aggressive squamous/basal/quasi-mesenchymal[JP3] subtype, clinically presenting as highly metastatic and harboring genetic amplifications of KRAS. Our previous work indicated that a squamous identity gene, Parathyroid Hormone Like Hormone (PTHLH; encoding for the PTHrP protein), is frequently co-amplified with KRAS and skews PDAC towards a squamous identity. Further, PTHrP is secreted by tumor cells and promotes tumor growth and metastasis through autocrine signaling. However, pathological analysis of PTHrP-null tumors indicated that the tumor microenvironment (TME) was re-organized upon loss of PTHrP. Thus, we hypothesized that PTHrP is a tumor-derived factor that shapes the TME through its systemic secretion and mobilization of immunosuppressive myeloid cells. Methods: In vivo experiments used KrasG12D; p53R172H; Pdx1-Cre; YFP (KPCY) and KPCY-PthlhloxP/WT (KPCY-Pthlhhet) for spontaneous tumor formation in immune competent mice. Orthotopic implantation experiments used Pthlh overexpressing KPCY tumor cells (herein KPCY-PthlhOE) or empty vector control cells (KPCY-PthlhEV). Tumor immunophenotyping was done using flow cytometry. Cytokine expression was performed using qPCR and ELISA. Results: In vivo investigation of tumors from KPCY-Pthlhhet mice revealed less MDSC and greater CD8+ T cell infiltration than KPCY controls, demonstrating the necessity of PTHrP for immunosuppression[PJ4]. Orthotopic implantation of KPCY-PthlhOE cell lines reduced overall TME immune cell recruitment, while simultaneously increasing the proportion of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) infiltration. A concomitant decrease in the frequency of T cells in the KPCY-PthlhOE tumors was also observed, showing the sufficiency of PTHrP to organize an immunosuppressive TME[PJ5]. Additionally, a reduction of PD-1+ and CD44high CD8+ T cells revealed they were less activated. Interestingly, recombinant human PTHrP was sufficient to induce MDSC mobilization in vivo.[JP6] To interrogate the mechanism of MDSC trafficking into the TME, cytokine production by was analyzed in vitro. KPCY-PthlhOE exhibited a pronounced increase and decrease of Cxcl1 and Cxcl10 expression, respectively, relative to the KPCY-EV control. Conclusions: The work herein describes a new mechanism for the mobilization and infiltration of immune suppressive MDSC in the tumor microenvironment, initiated by PTHrP. The PTHrP-dependent immunosuppressive TME excludes and inhibits effector immune cells, such as CD8+ T cells. This phenomenon has been described in squamous-like PDAC but may also apply to other squamous adenocarcinomas. [PJ7] Further elucidation of the mechanism by which PTHrP is the genesis of the immune suppressive TME may spur the development of novel treatments for these more clinically severe cancer subtypes. Citation Format: Calvin P. Johnson, Boyang Ma, Jason Pitarresi. Tumor-derived PTHrP molds an immunosuppressive microenvironment [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B019.

TRIM65 knockout inhibits the development of HCC by polarization tumor-associated macrophages towards M1 phenotype via JAK1/STAT1 signaling pathway

Background & aimsTumor-associated macrophages (TAMs) are main components of immune cells in tumor microenvironment (TME), and play a crucial role in tumor progression. Tripartite motif-containing protein 65 (TRIM65) has been associated with tumor progression. However, whether TRIM65 regulate the interaction of tumor cell and TAMs in HCC and the underlying mechanisms remain unknown. In this study, we investigated the role of TRIM65 in TME of HCC and explored its underlying mechanisms. MethodsThe relation of TRIM65 expression level with tumor grades, TNM stages, and worse prognosis of HCC patients was evaluated by bioinformatics analysis, as well as immune infiltration level of macrophages. TRIM65 shRNA was transfected into HepG2 cells, and TRIM65 overexpression plasmid was transfected into Huh7 cells, and the effect of TRIM65 on cell growth was examined by EdU assay. The mouse subcutaneous Hep1-6 tumor-bearing model with WT and TRIM65-/- mice was established to study the role of TRIM65 in HCC. Immunohistochemistry staining, Immunofluorescence staining, qRT-PCR and western blot were performed to evaluate the effect of TRIM65 on TAM infiltration, TAM polarization and JAK1/STAT1 signaling pathway. ResultsBioinformatics analysis revealed that TRIM65 was upregulated in 16 types of cancer especially in HCC, and high level of TRIM65 was strongly correlated with higher tumor grades, TNM stages, and worse prognosis of patients with HCC as well as immune infiltration level of macrophages (M0, M1, and M2). Moreover, we observed that TRIM65 shRNA-mediated TRIM65 knockdown significantly inhibited the HepG2 cells growth while TRIM65 overexpression highly increased the Huh7 cells growth in vitro. TRIM65 knockout significantly inhibited the tumor growth as well as macrophages polarization towards M2 but promoted macrophages polarization towards M1 in vivo. Mechanistically, the results demonstrate that TRIM65 knockout promoted macrophage M1 polarization in conditioned medium-stimulated peritoneal macrophages and in tumor tissues by activating JAK1/STAT1 signaling pathway. ConclusionsTaken together, our study suggests that tumor cells utilize TRIM65-JAK1/STAT1 axis to inhibit macrophage M1 polarization and promote tumor growth, reveals the role of TRIM65 in TAM-targeting tumor immunotherapy.

Analyzing the impact of metabolism on immune cells in tumor microenvironment to promote the development of immunotherapy.

Tumor metabolism and tumor immunity are inextricably linked. Targeting the metabolism of tumors is a point worth studying in tumor immunotherapy. Recently, the influence of the metabolism of tumors and immune cells on the occurrence, proliferation, metastasis, and prognosis of tumors has attracted more attention. Tumor tissue forms a specific tumor microenvironment (TME). In addition to tumor cells, there are also immune cells, stromal cells, and other cells in TME. To adapt to the environment, tumor cells go through the metabolism reprogramming of various substances. The metabolism reprogramming of tumor cells may further affect the formation of the tumor microenvironment and the function of a variety of cells, especially immune cells, eventually promoting tumor development. Therefore, it is necessary to study the metabolism of tumor cells and its effects on immune cells to guide tumor immunotherapy. Inhibiting tumor metabolism may restore immune balance and promote the immune response in tumors. This article will describe glucose metabolism, lipid metabolism, amino acid metabolism, and immune cells in tumors. Besides, the impact of metabolism on the immune cells in TME is also discussed for analyzing and exploring tumor immunotherapy.

Increased CD16a (FcγRIIIA) Expression in The Tumor Microenvironment of Atypical Neurofibromatous Neoplasms of Uncertain Biologic Potential May Be Associated with Progression from Neurofibromas to Atypical Neurofibromas.

Neurofibroma (NF) is a benign tumor in the peripheral nervous system, but it can infiltrate around structures and cause functional impairment and disfigurement. We incidentally found that the expression of CD16a (Fc gamma receptor IIIA) was increased in NFs compared to in non-neoplastic nerves and hypothesized that CD16 could be relevant to NF progression. We evaluated the expressions of CD16a, CD16b, CD68, TREM2, Galectin-3, S-100, and SOX10 in 38 cases of neurogenic tumors (NF, n = 18; atypical neurofibromatous neoplasm of uncertain biologic potential (ANNUBP), n = 14; and malignant peripheral nerve sheath tumor (MPNST), n = 6) by immunohistochemical staining. In the tumor microenvironment (TME) of the ANNUBPs, CD16a and CD16b expression levels had increased more than in the NFs or MPNSTs. CD68 and Galectin-3 expression levels in the ANNUBPs were higher than in the MPNSTs. Dual immunohistochemical staining showed an overlapping pattern for CD16a and CD68 in TME immune cells. Increased CD16a expression was detected in the ANNUBPs compared to the NFs but decreased with malignant progression. The CD16a overexpression with CD68 positivity in the ANNUBPs potentially reflects that the TME immune modulation could be associated with NF progression to an ANNUBP. Further studies should explore the role of CD16a in immunomodulation for accelerating NF growth.

The effect of cuproptosis-relevant genes on the immune infiltration and metabolism of gynecological oncology by multiply analysis and experiments validation

Gynecological cancers are a leading cause of mortality for women, including ovarian cancer (OC), cervical squamous cell carcinoma (CESC), and uterine corpus endometrial carcinoma (UCEC). Nevertheless, these gynecological cancer types have not elucidated the role of cuproptosis and the correlated tumor microenvironment (TME) infiltration features. CRGs had important potential molecular functions and prognostic significance in gynecological cancers, especially in UCEC. Hub CRG, FDX1, was correlated with the CD8+ T cell immune infiltration in UCEC and CESC. FDX1 OE could significantly repress the proliferation ability in UCEC cells by MTT, EdU, and clone formation. High levels of FDX1 could repress ATP and lactic acid but enhance ROS and glucose levels by metabolism assay. The xenograft tumor model indicated that FDX1 OE significantly inhibited the growth of UCEC and attenuated the PCNA, HK2, PKM2, and Ki-67 expression. These CRGs are significant roles that could be potential markers and treatment targets to optimize the TME immune cell infiltration features for gynecological cancer types. FDX1 is a hub CRGs in UCEC to promote immune infiltration and attenuate proliferation and metabolism.

Formaldehyde promotes tumor-associated macrophage polarizations and functions through induction of HIF-1α-mediated glycolysis

Formaldehyde (FA) exposure has been positively correlated with many diseases including various types of cancers. However, the mechanisms of FA-related carcinogenesis are still unclear. Tumor-associated macrophages (TAMs) are the most abundant immune cells in tumor microenvironment, which is a heterogeneous population consist of both pro-inflammatory (M1) and immunosuppressive (M2) cells. TAMs are deeply involved in tumor development and progression. Our previous studies demonstrated that FA enhanced M1 polarization of macrophages through induction of HIF-1α-mediated glycolysis. To examine if TAM polarizations are also potentiated by FA, BALB/c nude mice were inoculated with A549 cells to develop subcutaneous tumors and exposed to 2.0 mg/m3 FA for 14 days. Significant increases of both M1 and M2 polarizations of TAMs were observed in tumor tissues of FA-exposed mice. After confirmation of the potentiation effects in RAW264.7 and THP-1-derived in vitro TAM models, FA at 25 and 50 μM was found to enhance TAM immunosuppressive functions and glycolytic metabolism. In addition, FA-induced glycolysis in TAMs was reversed by a specific HIF-1α inhibitor PX-478 at 5 μM, and suppression of glycolytic metabolism with a glucose analog 2-DG at 1 mM also alleviated FA-potentiated TAM functions, which indicated that FA induced TAM polarizations through the upregulation of HIF-1α-mediated glycolysis. These results illustrated a potential carcinogenic mechanism of FA through metabolic disturbance of tumor immunity, which could be utilized to develop preventative or therapeutic agents for FA-induced carcinogenesis and immune disorders.

ScCURE identifies cell types responding to immunotherapy and enables outcome prediction

A deep understanding of immunotherapy response/resistance mechanisms and a highly reliable therapy response prediction are vital for cancer treatment. Here, we developed scCURE (single-cell RNA sequencing [scRNA-seq] data-based Changed and Unchanged cell Recognition during immunotherapy). Based on Gaussian mixture modeling, Kullback-Leibler (KL) divergence, and mutual nearest-neighbors criteria, scCURE can faithfully discriminate between cells affected or unaffected by immunotherapy intervention. By conducting scCURE analyses in melanoma and breast cancer immunotherapy scRNA-seq data, we found that the baseline profiles of specific CD8+ T and macrophage cells (identified by scCURE) can determine the way in which tumor microenvironment immune cells respond to immunotherapy, e.g., antitumor immunity activation or de-activation; therefore, these cells could be predictive factors for treatment response. In this work, we demonstrated that the immunotherapy-associated cell-cell heterogeneities revealed by scCURE can be utilized to integrate the therapy response mechanism study and prediction model construction.

Histone lactylation regulates cancer progression by reshaping the tumor microenvironment.

As a major product of glycolysis and a vital signaling molecule, many studies have reported the key role of lactate in tumor progression and cell fate determination. Lactylation is a newly discovered post-translational modification induced by lactate. On the one hand, lactylation introduced a new era of lactate metabolism in the tumor microenvironment (TME), and on the other hand, it provided a key breakthrough point for elucidation of the interaction between tumor metabolic reprogramming and epigenetic modification. Studies have shown that the lactylation of tumor cells, tumor stem cells and tumor-infiltrating immune cells in TME can participate in the development of cancer through downstream transcriptional regulation, and is a potential and promising tumor treatment target. This review summarized the discovery and effects of lactylation, as well as recent research on histone lactylation regulating cancer progression through reshaping TME. We also focused on new strategies to enhance anti-tumor effects via targeting lactylation. Finally, we discussed the limitations of existing studies and proposed new perspectives for future research in order to further explore lactylation targets. It may provide a new way and direction to improve tumor prognosis.