Cell Antitumor Immunity Research Articles

JAM3: A prognostic biomarker for bladder cancer via epithelial-mesenchymal transition regulation.

Understanding the intricate relationship between prognosis, immune function, and molecular markers in bladder cancer (BC) demands sophisticated analytical methods. To identify novel biomarkers for predicting prognosis and immune function in BC patients, we combined weighted gene co-expression network analysis (WGCNA) and least absolute shrinkage and selection operator (LASSO) regression analysis. This was conducted using data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Ultimately, we screened the junctional adhesion molecule 3 (JAM3) as an independent risk factor in BC. High levels of JAM3 were linked to adverse clinical parameters, such as higher T and N stages. Additionally, a JAM3-based nomogram model accurately predicted 1-, 3- and 5-year survival rates of BC patients, indicating potential clinical utility. Functional enrichment analysis revealed that high JAM3 expression activated the calcium signaling pathway, the extracellular matrix (ECM)-receptor interaction, and the PI3K-Akt signaling pathway, and was positively correlated with genes associated with epithelial-mesenchymal transition (EMT). Subsequently, we found that overexpression of JAM3 promoted the migration and invasion abilities in BC cells, regulating the expression levels of N-cadherin, matrix metallopeptidase 2 (MMP2), and Claudin-1 thereby promoting EMT levels. Additionally, we showed that JAM3 was negatively correlated with anti-tumor immune cells such as CD8+ T cells, while positively correlated with pro-tumor immune cells such as M2 macrophages, suggesting its involvement in immune cell infiltration. The immune checkpoint CD200 also showed a positive correlation with JAM3. Our findings revealed that elevated JAM3 levels are predictive of poor prognosis and immune cell infiltration in BC patients by regulating the EMT process.

Novel insights into Notch signaling in tumor immunity: potential targets for cancer immunotherapy.

Notch signaling pathway is a highly conserved system of cell-to-cell communication that participates in various biological processes, such as stem cell maintenance, cell fate decision, cell proliferation and death during homeostasis and development. Dysregulation of Notch signaling has been associated with many aspects of cancer biology, such as maintenance of cancer stem-like cells (CSCs), cancer cell metabolism, angiogenesis and tumor immunity. Particularly, Notch signaling can regulate antitumor or pro-tumor immune cells within the tumor microenvironment (TME). Currently, Notch signaling has drawn significant attention in the therapeutic development of cancer treatment. In this review, we focus on the role of Notch signaling pathway in remodeling tumor immune microenvironment. We describe the impact of Notch signaling on the efficacy of cancer immunotherapies. Furthermore, we summarize the results of relevant preclinical and clinical trials of Notch-targeted therapeutics and discuss the challenges in their clinical application in cancer therapy. An improved understanding of the involvement of Notch signaling in tumor immunity will open the door to new options in cancer immunotherapy treatment.

Depletion of PHLDB2 Suppresses Epithelial-Mesenchymal Transition and Enhances Anti-Tumor Immunity in Head and Neck Squamous Cell Carcinoma.

The role of Pleckstrin homology-like domain family B member 2 (PHLDB2) in the regulation of cell migration has been extensively studied. However, the exploration of PHLDB2 in head and neck squamous cell carcinoma (HNSCC) is still limited in terms of expression, function, and therapeutic potential. In this study, we discovered an upregulation of PHLDB2 expression in HNSCC tissues which was correlated with a negative prognosis in patients with HNSCC. Additionally, we determined that a high level of expression of PHLDB2 is crucial for maintaining cell migration through the regulation of the epithelial-mesenchymal transition (EMT). Furthermore, we demonstrated that the ablation of PHLDB2 in tumor cells inhibited tumorigenicity in a C3H syngeneic tumor-bearing mouse model. Mechanistically, PHLDB2 was found to be involved in the regulation of T cell anti-tumor immunity, primarily by enhancing the activation and infiltration of CD8+ T cells. In light of these findings, PHLDB2 emerges as a promising biomarker and therapeutic target for interventions in HNSCC.

Cystine deprivation triggers CD36-mediated ferroptosis and dysfunction of tumor infiltrating CD8+ T cells

Cancer cells develop multiple strategies to evade T cell-mediated killing. On one hand, cancer cells may preferentially rely on certain amino acids for rapid growth and metastasis. On the other hand, sufficient nutrient availability and uptake are necessary for mounting an effective T cell anti-tumor response in the tumor microenvironment (TME). Here we demonstrate that tumor cells outcompete T cells for cystine uptake due to high Slc7a11 expression. This competition induces T-cell exhaustion and ferroptosis, characterized by diminished memory formation and cytokine secretion, increased PD-1 and TIM-3 expression, as well as intracellular oxidative stress and lipid-peroxide accumulation. Importantly, either Slc7a11 deletion in tumor cells or intratumoral cystine supplementation improves T cell anti-tumor immunity. Mechanistically, cystine deprivation in T cells disrupts glutathione synthesis, but promotes CD36 mediated lipid uptake due to dysregulated cystine/glutamate exchange. Moreover, enforced expression of glutamate-cysteine ligase catalytic subunit (Gclc) promotes glutathione synthesis and prevents CD36 upregulation, thus boosting T cell anti-tumor immunity. Our findings reveal cystine as an intracellular metabolic checkpoint that orchestrates T-cell survival and differentiation, and highlight Gclc as a potential therapeutic target for enhancing T cell anti-tumor function.

Immune-related long noncoding RNA zinc finger protein 710-AS1-201 promotes the metastasis and invasion of gastric cancer cells.

Gastric cancer (GC) is a prevalent malignant tumor of the gastrointestinal system. ZNF710 is a transcription factor (TF), and zinc finger protein 710 (ZNF710)-AS1-201 is an immune-related long noncoding RNA (lncRNA) that is upregulated in GC cells. To assess the correlation between ZNF710-AS1-201 and immune microenvironment features and to investigate the roles of ZNF710-AS1-201 in the invasion and metastasis processes of GC cells. We obtained data from The Cancer Genome Atlas and Wujin Hospital. We assessed cell growth, migration, invasion, and programmed cell death using cell counting kit-8, EdU, scratch, Transwell, and flow cytometry assays. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to identify the potential downstream targets of ZNF710-AS1-201. In GC tissues with low ZNF710-AS1-201 expression, immunoassays detected significant infiltration of various antitumor immune cells, such as memory CD8 T cells and activated CD4 T cells. In the low-expression group, the half-maximal inhibitory concentrations (IC50s) of 5-fluorouracil, cisplatin, gemcitabine, and trametinib were lower, whereas the IC50s of dasatinib and vorinostat were higher. The malignant degree of GC was higher and the stage was later in the high-expression group. Additionally, patients with high expression of ZNF710-AS1-201 had lower overall survival and disease-free survival rates. In vitro, the overexpression of ZNF710-AS1-201 greatly enhanced growth, metastasis, and infiltration while suppressing cell death in HGC-27 cells. In contrast, the reduced expression of ZNF710-AS1-201 greatly hindered cell growth, enhanced apoptosis, and suppressed the metastasis and invasion of MKN-45 cells. The expression changes in ZNF710 were significant, but the corresponding changes in isocitrate dehydrogenase-2, Semaphorin 4B, ARHGAP10, RGMB, hsa-miR-93-5p, and ZNF710-AS1-202 were not consistent or statistically significant after overexpression or knockdown of ZNF710-AS1-201, as determined by qRT-PCR. Immune-related lncRNA ZNF710-AS1-201 facilitates the metastasis and invasion of GC cells. It appears that ZNF710-AS1-201 and ZNF710 have potential as effective targets for therapeutic intervention in GC. Nevertheless, it is still necessary to determine the specific targets of the ZNF710 TF.

Endothelial cells in tumor microenvironment: insights and perspectives.

The tumor microenvironment is a highly complex and dynamic mixture of cell types, including tumor, immune and endothelial cells (ECs), soluble factors (cytokines, chemokines, and growth factors), blood vessels and extracellular matrix. Within this complex network, ECs are not only relevant for controlling blood fluidity and permeability, and orchestrating tumor angiogenesis but also for regulating the antitumor immune response. Lining the luminal side of vessels, ECs check the passage of molecules into the tumor compartment, regulate cellular transmigration, and interact with both circulating pathogens and innate and adaptive immune cells. Thus, they represent a first-line defense system that participates in immune responses. Tumor-associated ECs are involved in T cell priming, activation, and proliferation by acting as semi-professional antigen presenting cells. Thus, targeting ECs may assist in improving antitumor immune cell functions. Moreover, tumor-associated ECs contribute to the development at the tumor site of tertiary lymphoid structures, which have recently been associated with enhanced response to immune checkpoint inhibitors (ICI). When compared to normal ECs, tumor-associated ECs are abnormal in terms of phenotype, genetic expression profile, and functions. They are characterized by high proliferative potential and the ability to activate immunosuppressive mechanisms that support tumor progression and metastatic dissemination. A complete phenotypic and functional characterization of tumor-associated ECs could be helpful to clarify their complex role within the tumor microenvironment and to identify EC specific drug targets to improve cancer therapy. The emerging therapeutic strategies based on the combination of anti-angiogenic treatments with immunotherapy strategies, including ICI, CAR T cells and bispecific antibodies aim to impact both ECs and immune cells to block angiogenesis and at the same time to increase recruitment and activation of effector cells within the tumor.

INPP4B ensures that ILC1s and NK cells set up a productive home office.

In this issue of JEM, Peng et al. (https://doi.org/10.1084/jem.20230124) identify inositol polyphosphate 4-phosphatase type II (encoded by Inpp4b) as an important enzyme for tissue-resident ILC1 and NK cell survival, signal transduction, and anti-tumor immunity.

Heat shock protein gp96 drives natural killer cell maturation and anti-tumor immunity by counteracting Trim28 to stabilize Eomes

The maturation process of natural killer (NK) cells, which is regulated by multiple transcription factors, determines their functionality, but few checkpoints specifically targeting this process have been thoroughly studied. Here we show that NK-specific deficiency of glucose-regulated protein 94 (gp96) leads to decreased maturation of NK cells in mice. These gp96-deficient NK cells exhibit undermined activation, cytotoxicity and IFN-γ production upon stimulation, as well as weakened responses to IL-15 for NK cell maturation, in vitro. In vivo, NK-specific gp96-deficient mice show increased tumor growth. Mechanistically, we identify Eomes as the downstream transcription factor, with gp96 binding to Trim28 to prevent Trim28-mediated ubiquitination and degradation of Eomes. Our study thus suggests the gp96-Trim28-Eomes axis to be an important regulator for NK cell maturation and cancer surveillance in mice.

Single-Site Nanozymes with a Highly Conjugated Coordination Structure for Antitumor Immunotherapy via Cuproptosis and Cascade-Enhanced T Lymphocyte Activity.

The extracellular matrix (ECM) in the tumor microenvironment (TME) and upregulated immune checkpoints (ICs) on antitumor immune cells impede the infiltration and killing effect of T cells, creating an immunosuppressive TME. Herein, a cholesterol oxidase (CHO) and lysyl oxidase inhibitor (LOX-IN-3) co-delivery copper-dibenzo-[g,p]chrysene-2,3,6,7,10,11,14,15-octaol single-site nanozyme (Cu-DBCO/CL) was developed. The conjugated organic ligand and well-distributed Cu-O4 sites endow Cu-DBCO with unique redox capabilities, enabling it to catalyze O2 and H2O2 to ·O2- and ·OH. This surge of reactive oxygen species (ROS) leads to impaired mitochondrial function and insufficient ATP supply, impacting the function of copper-transporting ATPase-1 and causing dihydrolipoamide S-acetyltransferase oligomerization-mediated cuproptosis. Moreover, multiple ROS storms and glutathione peroxidase 4 depletion also induce lipid peroxidation and trigger ferroptosis. Simultaneously, the ROS-triggered release of LOX-IN-3 reshapes the ECM by inhibiting lysyl oxidase activity and further enhances the infiltration of cytotoxic T lymphocytes (CD8+ T cells). CHO-triggered cholesterol depletion not only increases ·OH generation but also downregulates the expression of ICs such as PD-1 and TIM-3, restoring the antitumor activity of tumor-infiltrating CD8+ T cells. Therefore, Cu-DBCO/CL exhibits efficient properties in activating a potent antitumor immune response by cascade-enhanced CD8+ T cell viability. More importantly, ECM remodeling and cholesterol depletion could suppress the metastasis and proliferation of the tumor cells. In short, this immune nanoremodeler can greatly enhance the infiltration and antitumor activity of T cells by enhancing tumor immunogenicity, remodeling ECM, and downregulating ICs, thus achieving effective inhibition of tumor growth and metastasis.

Paired single-B-cell transcriptomics and receptor sequencing reveal activation states and clonal signatures that characterize B cells in acute myeloid leukemia

BackgroundAcute myeloid leukemia (AML) is associated with a dismal prognosis. Immune checkpoint blockade (ICB) to induce antitumor activity in AML patients has yielded mixed results. Despite the pivotal role of...

Abstract A028: Disparities in suppressive immunity in Hispanic/Latina patients with hormone receptor positive breast cancer

Abstract In the US, breast cancer is the number one cancer diagnosed, and it is responsible for the most cancer related deaths among Hispanic/Latina (H/L) women. The mean age of diagnosis of breast cancer in H/L patients is 3.7 years younger than their Non-Hispanic White (NHW) counterparts. Despite being diagnosed with breast cancer at a younger age, the H/L population has a better overall survival rate across all breast cancer subtypes. This study investigates whether the immune response mounted against tumor cells in the H/L population differs from that mounted by NHW patients. We recruited and received consent from patients diagnosed with stage I- III (early stage), or stage IV/advanced (metastatic), hormone receptor positive (HR+) breast cancer. We collected blood from 66 patients (38 H/L, 28 NHW) across all stages of disease, and tumor tissue from 14 unmatched patients (7 H/L, 7 NHW), with early stage disease, at the time of tumor resection, none of whom had received neoadjuvant chemotherapy. We utilized multiparameter flow cytometry to analyze peripheral blood mononuclear cells (PBMCs), and 10X Visium for spatial transcriptomic and proteomic evaluation of patient’s tumor tissue to characterize differences in immune composition by race. We hypothesize that evaluation of intra-tumoral immune composition will reveal fewer immune suppressor cells and increased infiltration of cytotoxic immune cells in tumors from H/L patients. We also hypothesize evaluation of immune cells in circulation will mirror findings from within tumors. Suppressor immune cells, comprised of M2-polarized macrophages, myeloid derived suppressor cells (MDSCs), and T regulatory cells (Tregs) modulate T cell proliferation and cytotoxicity to affect anti-tumor immunity. We report a significant difference in the levels of both anti-tumoral and suppressive immune cells in the periphery within the H/L patient population when comparing early vs. metastatic HR+ breast cancer. This was not observed in the NHW group and there were no differences when comparing peripheral suppressor and T cell populations in H/L vs. NHW at any stage. Comparisons of intra-tumoral immune cell infiltration and differences in transcription profiles are forthcoming. The findings from this study will be some of the first to look at the immune composition in H/L women with HR+ disease, and could provide data to support larger studies leading to a paradigm shift in how we approach clinical trial design for immune checkpoint inhibition. Citation Format: Sabrina Carrel, Michelle Li, Batul Al-Zubeidy, Dominic Zavala, Edgar Gonzales, Aaron Baugh, Sofi Castanon, Robert Hsu, Dimitrios N Sidiropoulos, Yanling Ma, Michael Press, Evanthia T Roussos Torres. Disparities in suppressive immunity in Hispanic/Latina patients with hormone receptor positive breast cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Breast Cancer Research; 2023 Oct 19-22; San Diego, California. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_1):Abstract nr A028.

Abstract A022: Dissecting patterns of small cell lung cancer evolution using deep whole genome sequencing of circulating tumor DNA

Abstract Background: Small cell lung cancer (SCLC) is the most lethal form of lung cancer. A key driver of this near universal lethality is SCLC’s recalcitrance to therapy. The standard of care for SCLC is a chemotherapy doublet of etoposide and cis/carboplatin in combination with immunotherapy (EP+IO). While most tumors respond to these therapies, >80% of SCLCs progress within one year of treatment. Additionally, the aggressive clinical course of SCLC has historically precluded collection of patient-matched treatment naïve and recurrent tumor tissue traditionally required to study evolution. In lieu of tissue, several groups have used circulating tumor DNA (ctDNA) to study SCLC evolution. However, these studies used targeted sequencing panels that analyze <0.04% of the SCLC genome. Using new methods to comprehensively trace how SCLCs rapidly evolve to therapy resistance is a significant unmet need. Methods: Medical records were reviewed to identify treatment naïve SCLC patients treated at MD Anderson that had both pre- and post-EP+IO liquid biopsies collected under IRB approved protocols. ctDNA was isolated from plasma using a MiniMax High Efficiency Cell-Free DNA Isolation Kit (Apostle Bio). Germline DNA was extracted from buffy coat samples using a QIAamp DNA Blood Midi Kit (Qiagen). Deep whole genome sequencing (WGS) (>100X) of ctDNA and WGS of germline DNA (>60X) was performed using an Illumina NovaSeq X sequencer. Reads were aligned to the hg38 reference genome using BWA-mem. Somatic mutations were called using MuTect2, and clonal and subclonal copy number alterations were identified using Battenberg. DPClust was used to reconstruct cancer cell populations, leveraging mutation and copy number calls. Results: We identified several deleterious genomic alterations impacting TP53 and RB1 tumor suppressor genes, known genetic drivers of SCLC development. We also detected recurrent, whole chromosome arm loss of heterozygosity events impacting many chromosomes in treatment naïve samples, some of which are known to be present in >80% of SCLCs. Additionally, we found that both treatment naïve and recurrent SCLCs were composed of multiple subclones, each defined by dozens to thousands of unique somatic mutations. COSMIC signature analysis identified high activity of tobacco carcinogens, APOBEC, and replicative-based processes across ctDNA samples. We also identified emergence of novel subclones carrying unique copy number alterations following EP+IO recurrence. Importantly, the affected regions encode key effectors that regulate anti-tumor immune responses and cell survival following DNA damage, both of which are intimately related to the mechanism of action of EP+IO. Conclusions: Our data shows that deep WGS of ctDNA recapitulates known genetics of SCLC and allows for sensitive characterization of therapy resistant clones. Using this method, we have captured snapshots of both intrinsic and acquired resistance mechanisms to frontline EP+IO. Deep WGS of ctDNA is a promising approach to comprehensively dissect routes of SCLC evolution and therapy resistance. Citation Format: Benjamin B. Morris, Zhihui Zhang, Simon Heeke, Kyle Concannon, Bingan Zhang, Waree Rinsurongkawong, Vadeerat Rinsurongkawong, J. Jack Lee, Jianjun Zhang, Don L. Gibbons, Ara A. Vaporciyan, Carl M. Gay, Hai T. Tran, John V. Heymach, Lauren A. Byers, Peter Van Loo. Dissecting patterns of small cell lung cancer evolution using deep whole genome sequencing of circulating tumor DNA [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Translating Cancer Evolution and Data Science: The Next Frontier; 2023 Dec 3-6; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_2):Abstract nr A022.

Bladder Cancer: Immunotherapy and Pelvic Lymph Node Dissection.

Bladder cancer, a common malignancy of the urinary system, is routinely treated with radiation, chemotherapy, and surgical excision. However, these strategies have inherent limitations and may also result in various side effects. Immunotherapy has garnered considerable attention in recent years as a novel therapeutic approach. It harnesses and activates the patient's immune system to recognize and eliminate cancer cells, which not only prolongs therapeutic efficacy but also minimizes the toxic side effects. Several immune checkpoint inhibitors and cancer vaccines have been developed for the treatment of bladder cancer. Whereas blocking immune checkpoints on the surface of tumor cells augments the effect of immune cells, immunization with tumor-specific antigens can elicit the production of anti-tumor immune effector cells. However, there are several challenges in applying immunotherapy against bladder cancer. For instance, the efficacy of immunotherapy varies considerably across individual patients, and only a small percentage of cancer patients are responsive. Therefore, it is crucial to identify biomarkers that can predict the efficacy of immunotherapy. Pelvic lymph nodes are routinely dissected from bladder cancer patients during surgical intervention in order to remove any metastatic tumor cells. However, some studies indicate that pelvic lymph node dissection may reduce the efficacy of immunotherapy by damaging the immune cells. Therefore, the decision to undertake pelvic lymph node removal should be incumbent on the clinical characteristics of individual patients. Thus, although immunotherapy has the advantages of lower toxic side effects and long-lasting efficacy, its application in bladder cancer still faces challenges, such as the lack of predictive biomarkers and the effects of pelvic lymph node dissection. Further research is needed to explore these issues in order to improve the efficacy of immunotherapy for bladder cancer.

Targeting focal adhesion kinase boosts immune response in KRAS/LKB1 co-mutated lung adenocarcinoma via remodeling the tumor microenvironment

BackgroundKRAS mutation is one of the most common oncogenic drivers in NSCLC, however, the response to immunotherapy is heterogeneous owing to the distinct co-occurring genomic alterations. KRAS/LKB1 co-mutated lung adenocarcinoma displays poor response to PD-1 blockade whereas the mechanism remains undetermined.MethodsWe explored the specific characteristics of tumor microenvironment (TME) in KL tumors using syngeneic KRASG12DLKB1−/− (KL) and KRASG12DTP53−/− (KP) lung cancer mouse models. The impact of focal adhesion kinase (FAK) inhibitor on KL lung tumors was investigated in vitro and in vivo through evaluation of both KL cell lines and KL lung cancer mouse models.ResultsWe identified KL tumors as “immune-cold” tumors with excessive extracellular matrix (ECM) collagen deposition that formed a physical barrier to block the infiltration of CD8+T cells. Mechanistically, abundant activated cancer-associated fibroblasts (CAFs) resulted from FAK activation contributed to the formation of the unique TME of KL tumors. FAK inhibition with a small molecular inhibitor could remodel the TME by inhibiting CAFs activation, decreasing collagen deposition and further facilitating the infiltration of anti-tumor immune cells, including CD8+ T cells, DC cells and M1-like macrophages into tumors, hence, converting “immune-cold” KL tumors into “immune-hot” tumors. The combined FAK inhibitor and PD-1 blockade therapy synergistically retarded primary and metastatic tumor growth of KL tumors.ConclusionsOur study identified FAK as a promising intervention target for KL tumors and provided basis for the combination of FAK inhibitor with PD-1 blockade in the management of KL lung cancers.

Discovering the strength of immunometabolism in cancer therapy: Employing metabolic pathways to enhance immune responses.

Immunometabolism, which studies cellular metabolism and immune cell function, is a possible cancer treatment. Metabolic pathways regulate immune cell activation, differentiation, and effector functions, crucial to tumor identification and elimination. Immune evasion and tumor growth can result from tumor microenvironment metabolic dysregulation. These metabolic pathways can boost antitumor immunity. This overview discusses immune cell metabolism, including glycolysis, oxidative phosphorylation, amino acid, and lipid metabolism. Amino acid and lipid metabolic manipulations may improve immune cell activity and antitumor immunity. Combination therapy using immunometabolism-based strategies may enhance therapeutic efficacy. The complexity of the metabolic network, biomarker development, challenges, and future approaches are all covered, along with a summary of case studies demonstrating the effectiveness of immunometabolism-based therapy. Metabolomics, stable isotope tracing, single-cell analysis, and computational modeling are also reviewed for immunometabolism research. Personalized and combination treatments are considered. This review adds to immunometabolism expertise and sheds light on metabolic treatments' ability to boost cancer treatment immunological response. Also, in this review, we discussed the immune response in cancer treatment and altering metabolic pathways to increase the immune response against malignancies.

Transcriptomic analysis of glucosidase II beta subunit (GluIIß) knockout A549 cells reveals its roles in regulation of cell adhesion molecules (CAMs) and anti-tumor immunity

Glucosidase II beta subunit (GluIIß), encoded from PRKCSH, is a subunit of the glucosidase II enzyme responsible for quality control of N-linked glycoprotein folding and suppression of GluIIß led to inhibitory effect of the receptor tyrosine kinase (RTKs) activities known to be critical for survival and development of cancer. In this study, we investigated the effect of GluIIß knockout on the global gene expression of cancer cells and its impact on functions of immune cells. GluIIß knockout lung adenocarcinoma A549 cell line was generated using CRISPR/Cas9-based genome editing system and subjected to transcriptomic analysis. Among 23,502 expressed transcripts, 1068 genes were significantly up-regulated and 807 genes greatly down-regulated. The KEGG enrichment analysis showed significant down-regulation of genes related extracellular matrix (ECM), ECM-receptor interaction, cytokine-cytokine receptor interaction and cell adhesion molecules (CAMs) in GluIIß knockout cells. Of 9 CAMs encoded DEG identified by KEGG enrichment analysis, real time RT-PCR confirmed 8 genes to be significantly down-regulated in all 3 different GluIIß knockout clones, which includes cadherin 4 (CDH4), cadherin 2 (CDH2), versican (VCAN), integrin subunit alpha 4 (ITGA4), endothelial cell-selective adhesion molecule (ESAM), CD274 (program death ligand-1 (PD-L1)), Cell Adhesion Molecule 1 (CADM1), and Nectin Cell Adhesion Molecule 3 (NECTIN3). Whereas PTPRF (Protein Tyrosine Phosphatase Receptor Type F) was significantly decreased only in 1 out of 3 knockout clones. Microscopic analysis revealed distinctively different cell morphology of GluIIβ knockout cells with lesser cytoplasmic and cell surface area compared to parental A549 cells and non-targeted transfected cells.Further investigations revealed that Jurkat E6.1 T cells or human peripheral blood mononuclear cells (PBMCs) co-cultured with GluIIß knockout A549 exhibited significantly increased viability and tumor cell killing activity compared to those co-cultured with non-target transfected cells. Analysis of cytokine released from Jurkat E6.1 T cells co-cultured with GluIIß knockout A549 cells showed significant increased level of angiogenin and significant decreased level of ENA-78. In conclusion, knockout of GluIIß from cancer cells induced altered gene expression profile that improved anti-tumor activities of co-cultured T lymphocytes and PBMCs thus suppression of GluIIß may represent a novel approach of boosting anti-tumor immunity.

Precisely Activating cGAS-STING Pathway with a Novel Peptide-Based Nanoagonist to Potentiate Immune Checkpoint Blockade Cancer Immunotherapy.

As an essential intracellular immune activation pathway, the cGAS-STING pathway has attracted broad attention in cancer treatment. However, low bioavailability, nonspecificity, and adverse effects of small molecule STING agonists severely limit their therapeutic efficacy and in vivo application. In this study, a peptide-based STING agonist is first proposed, and KLA is screened out to activate the cGAS-STING pathway by promoting mitochondrial DNA (mtDNA) leakage. To precisely activate the cGAS-STING pathway and block the PD-1/PD-L1 pathway, a multi-stimuli activatable peptide nanodrug (MAPN) is developed for the effective delivery of KLA and PD-L1 antagonist peptide (CVR). With rational design, MAPN achieved the site-specific release of KLA and CVR in response to multiple endogenous stimuli, simultaneously activating the cGAS-STING pathway and blocking PD-1/PD-L1 pathway, ultimately initiating robust and durable T cell anti-tumor immunity with a tumor growth inhibition rate of 78% and extending the median survival time of B16F10 tumor-bearing mice to 40 days. Overall, antimicrobial peptides, which can promote mtDNA leakage through damaging mitochondrial membranes, may be potential alternatives for small molecule STING agonists and giving a new insight for the design of novel STING agonists. Furthermore, MAPN presents a universal delivery platform for the effective synergy of multiple peptides.

Abstract PR05: CheMo4METPANC: Combination Chemotherapy (gemcitabine and nab-paclitaxel), chemokine (C-X-C) Motif receptor 4 inhibitor (motixafortide), and immune checkpoint blockade (cemiplimab) in METastatic treatment-naïve PANCreatic adenocarcinoma

Abstract Background: Metastatic pancreatic ductal adenocarcinoma (mPDAC) is a uniformly fatal disease. Immune checkpoint inhibitors have thus far failed to improve outcomes due to an immunosuppressive tumor microenvironment (TME). In preclinical mouse models, signaling through the C-X-C motif chemokine receptor 4 (CXCR4)/C-X-C motif chemokine ligand 12 (CXCL12) axis results in exclusion of anti-tumor immune cells. Using the KPC mouse PDAC model, we have demonstrated that treatment with the combination of a CXCR4 inhibitor (CXCR4i), αPD-1, and gemcitabine improves survival when compared to mice treated with either gemcitabine alone or the combination of CXCR4i and αPD-1 therapy. The goal of this first-in-human study was to test preliminary safety and radiologic response rate of motixafortide (CXCR4i), cemiplimab (αPD1), gemcitabine, and nab-paclitaxel (MCGN) in treatment-naïve mPDAC. Methods: This was an open label, multicenter, investigator-initiated, single arm pilot study evaluating MCGN in mPDAC. This signal seeking study incorporated a six-patient safety run-in cohort with enrollment of four additional patients (N=10). The primary aim of this trial was to study the safety of MCGN. If ≥3 of the initial 10 patients within the pilot stage experienced a partial response (PR) by RECIST criteria within 16 weeks, the combination would be considered promising and an expansion cohort of an additional 30 patients would be enrolled. Clinical trial information: NCT04543071. Results: A total of 11 patients (1 over-enrolled) with mPDAC participated in the study at Columbia University and Brown University (11/9/2020-3/3/2023). The median age was 58y. Two (18%) patients were female and 3 (27%) were black. As of 05/05/23, 6 (55%) patients experienced a partial response (PR) of which 4 (36%) were confirmed PRs with 1 patient experiencing resolution of the hepatic metastatic lesion. Three (27%) patients experienced stable disease. At a median follow-up of 9.5m, 5 remain on study (duration on treatment [DOT]: 11.6, 6.7, 3.7, 2.7, and 2 months), 4 are off treatment due to disease progression (DOT: 13.4, 9.7, 3.7, and 1.5 months), 1 withdrew consent, and 1 was removed per physician discretion. Five patients have died. As of 03/31/23, 9 patients experienced grade 3-4 treatment-related adverse events, including urticaria (18%), and allergic reaction, bone pain, hypertension, hypotension, pain, rash (each 9%). Analyses interrogating the TME, including single-cell profiling, will be presented on paired tumor biopsies obtained on all patients. Conclusions: Preliminary results from this pilot study of MCGN in mPDAC were promising, with a durable PR rate of 55% and disease control rate (DCR) of 82%, compared to historic PRs and DCRs of 23% and 48% reported with gemcitabine and nab-paclitaxel (GN), respectively. Based on these results, the study was amended to transition to a randomized phase 2 trial testing MCGN compared to GN (N=112). The primary endpoint is progression free survival (PFS). Citation Format: Gulam A. Manji, Michael May, Morteza Hajkarim Chalabi, Ilenia Pellicciotta, Sarah I. Sta Ana, Naomi Sender, Samuel S. Pan, Isabelle V. Ross, Kenneth P. Olive, Shikun Wang, Benjamin Izar, Ruth A. White, Susan E. Bates, Alexander G. Raufi. CheMo4METPANC: Combination Chemotherapy (gemcitabine and nab-paclitaxel), chemokine (C-X-C) Motif receptor 4 inhibitor (motixafortide), and immune checkpoint blockade (cemiplimab) in METastatic treatment-naïve PANCreatic adenocarcinoma [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 PR05.

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 C022: T cell movement through complex obstacles presented by the microenvironment of pancreatic tumor spheroids

Abstract Immunotherapy has emerged as a promising approach for treating pancreatic cancer, however its efficacy against solid tumors has been largely limited. In order to be effective, cell-based immunotherapies are required to be in close proximity with the target cancerous cells. However, owing to its dense desmoplastic stroma, many regions of a pancreatic tumor, have areas within the tumor volumes that exclude anti-tumor immune cells. Therefore, we need to define mechanisms used by therapeutic T cells to navigate effectively in some tumor regions and the barriers that limit their infiltration and distribution in other regions of the tumor microenvironment (TME). In this work, we have advanced our knowledge of T cell migration and infiltration through complex TMEs by analyzing T cell dynamics in 3D engineered in vitro environments that can replicate key TME features of pancreatic ductal adenocarcinoma (PDA). Using our state-of the-art imaging techniques with multiphoton excitation (MPE) and second harmonic generation (SHG), we have monitored the migration of engineered human mesothelin reactive CAR-T cells through fibrous microenvironments and their interactions with pancreatic tumor spheroids. Quantitative analysis of interactions between CAR-T cells and carcinoma cells, in terms of velocity, directionality and mean square displacement (MSD) were performed, with the aim of utilizing these phenotypes as “design criteria” for the development of more effective engineered T cell therapies. The therapeutic efficacy of engineered T cells was also evaluated in standard 2D killing assays and then new 3D assays of increased complexity, both of which revealed mesothelin specific cancer cell death. Overall, we are starting to define the physical and molecular mechanisms that result in resistance to immunotherapy against pancreatic cancer, and we anticipate that our work will be applicable to other solid tumors with similar challenges and address key unanswered question in cancer biology. Citation Format: Shambojit Roy, Zhongming Chen, Guhan Qian, Paolo P. Provenzano. T cell movement through complex obstacles presented by the microenvironment of pancreatic tumor spheroids [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 C022.