Critical Immune Checkpoint Research Articles

Kindlin-2-mediated hematopoiesis remodeling regulates triple-negative breast cancer immune evasion.

Triple-negative breast cancer (TNBC) presents significant clinical challenges due to its limited treatment options and aggressive behavior, often associated with poor prognosis. This study focuses on Kindlin-2, an adaptor protein, and its role in TNBC progression, particularly in hematopoiesis-mediated immune evasion. TNBC tumors expressing high levels of Kindlin-2 induce a notable reshaping of hematopoiesis, promoting expansion of myeloid cells in bone marrow (BM) and spleen. This shift correlated with increased levels of neutrophils and monocytes in tumor-bearing mice over time. Conversely, genetic knockout of Kindlin-2 mitigated this myeloid bias and fostered T cell infiltration within the tumor microenvironment, indicating Kindlin-2's pivotal role in immune modulation. Further investigations revealed that Kindlin-2 deficiency led to reduced expression of PD-L1, a critical immune checkpoint inhibitor, in TNBC tumors. This molecular change sensitized Kindlin-2-deficient tumors to host anti-tumor immune responses, resulting in enhanced tumor suppression in immune-competent mouse models. Single-cell RNA sequencing, bulk RNA-seq, and immunohistochemistry data supported these findings by highlighting enriched immune-related pathways and increased infiltration of immune cells in Kindlin-2-deficient tumors. Therapeutically, targeting PD-L1 in Kindlin-2-expressing TNBC tumors effectively inhibited tumor growth, akin to the effects observed with genetic Kindlin-2 knockout or PD-L1-KO. Our data underscore Kindlin-2 as a promising therapeutic target in combination with immune checkpoint blockade to bolster anti-tumor immunity and counteract resistance mechanisms typical of TNBC and other immune evasive solid tumors. Implications: Kindlin-2 regulates tumor immune evasion through the systemic modulation of hematopoiesis and PD-L1 expression, which warrants therapeutic targeting of Kindlin-2 in TNBC patients.

In silico Prediction of Pranlukast as a Stabilizer of PD-L1 Homodimers.

Tumors can be targeted by modulating the immune response of the patient. Programmed cell death protein 1 (PD-1) and programmed cell death ligand 1 (PD-L1) are critical immune checkpoints in cancer biology. The efficacy of certain cancer immunotherapies has been achieved by targeting these molecules using monoclonal antibodies. Small-molecule drugs have also been developed as inhibitors of the PD-1/PD-L1 axis, with a mechanism of action that is distinct from that of antibodies: they induce the formation of PD-L1 homodimers, causing their stabilization, internalization, and subsequent degradation. Drug repurposing is a strategy in which new uses are sought after for approved drugs, expediting their clinical translation based on updated findings. In this study, we generated a pharmacophore model that was based on reported small molecules that targeted PD-L1 and used it to identify potential PD-L1 inhibitors among FDA-approved drugs. We identified 12 pharmacophore-matching compounds, but only 4 reproduced the binding mode of the reference inhibitors in docking experiments. Further characterization by molecular dynamics showed that pranlukast, an antagonist of leukotriene receptors that is used to treat asthma, generated stable and energyfavorable interactions with PD-L1 homodimers and induced homodimerization of recombinant PD-L1. Our results suggest that pranlukast inhibits the PD-1/PD-L1 axis, meriting its repurposing as an antitumor drug.

Small-molecule inhibitors of the CD40-CD40L costimulatory interaction are effective in pancreatic islet transplantation and prevention of type 1 diabetes models.

As part of our work to develop small-molecule inhibitors (SMIs) of the CD40-CD40L(CD154) costimulatory protein-protein interaction, here, we describe the ability of two of our most promising SMIs, DRI-C21041 and DRI-C21095, to prolong the survival and function of islet allografts in two murine models of islet transplantation (under the kidney capsule and in the anterior chamber of the eye) and to prevent autoimmune type 1 diabetes (T1D) onset in NOD mice. In both transplant models, a significant portion of islet allografts (50%-80%) remained intact and functional long after terminating treatment, suggesting the possibility of inducing operational immune tolerance via inhibition of the CD40-CD40L axis. SMI-treated mice maintained the structural integrity and function of their islet allografts with concomitant reduction in immune cell infiltration as evidenced by direct longitudinal imaging in situ. Furthermore, in female NODs, three-month SMI treatment reduced the incidence of diabetes from 80% to 60% (DRI-C21041) and 25% (DRI-C21095). These results (i) demonstrate the susceptibility of this TNF superfamily protein-protein interaction to small-molecule inhibition, (ii) confirm the in vivo therapeutic potential of these SMIs of a critical immune checkpoint, and (iii) reaffirm the therapeutic promise of CD40-CD40L blockade in islet transplantation and T1D prevention. Thus, CD40L-targeting SMIs could ultimately lead to alternative immunomodulatory therapeutics for transplant recipients and prevention of autoimmune diseases that are safer, less immunogenic, more controllable (shorter half-lives), and more patient-friendly (i.e., suitable for oral administration, which makes them easier to administer) than corresponding antibody-based interventions.

Intrinsic PD-L1 Degradation Induced by a Novel Self-Assembling Hexapeptide for Enhanced Cancer Immunotherapy.

Programmed death-ligand 1 (PD-L1) is a critical immune checkpoint protein that facilitates tumor immune evasion. While antibody-based PD-1/PD-L1 inhibitors have shown promise, their limitations necessitate the development of alternative therapeutic strategies. This work addresses these challenges by developing a hexapeptide, KFM (Lys-Phe-Met-Phe-Met-Lys), capable of both directly downregulating PD-L1 and self-assembling into a ROS-responsive supramolecular hydrogel. This dual functionality allows Gel KFM to function as a localized drug delivery system and a PD-L1 inhibitor. Loading the hydrogel with mitoxantrone (MTX) and metformin (MET) further enhances the therapeutic effect by combining chemotherapy with PD-L1 downregulation. In vitro and in vivo studies demonstrate significant tumor growth inhibition, increased CD8+ T cell infiltration, and reduced intratumoral PD-L1 expression following peritumoral administration. Mechanistically, KFM promotes PD-L1 degradation via a ubiquitin-dependent pathway. This "carrier-free" delivery system expands the role of supramolecular hydrogels beyond passive carriers to active immunotherapeutic agents, offering a promising new strategy for cancer therapy.

Compression force promotes glioblastoma progression through the Piezo1‑GDF15‑CTLA4 axis.

Glioma, a type of brain tumor, is influenced by mechanical forces in its microenvironment that affect cancer progression. However, our understanding of the contribution of compression and its associated mechanisms remains limited. The objective of the present study was to create an environment in which human brain glioma H4 cells experience pressure and thereby investigate the compressive mechanosensors and signaling pathways. Subsequent time‑lapse imaging and wound healing assays confirmed that 12 h of compression significantly increased cell migration, thereby linking compression with enhanced cell motility. Compression upregulated the expression of Piezo1, a mechanosensitive ion channel, and growth differentiation factor 15 (GDF15), a TGF‑β superfamily member. Knockdown experiments targeting PIEZO1 or GDF15 using small interfering RNA resulted in reduced cell motility, with Piezo1 regulating GDF15 expression. Compression also upregulated CTLA4, a critical immune checkpoint protein. The findings of the present study therefore suggest that compression enhances glioma progression by stimulating Piezo1, promoting GDF15 expression and increasing CTLA4 expression. Thus, these findings provide important insights into the influence of mechanical compression on glioma progression and highlight the involvement of the Piezo1‑GDF15 signaling pathway. Understanding tumor responses to mechanical forces in the brain microenvironment may guide the development of targeted therapeutic strategies to mitigate tumor progression and improve patient outcomes.

Chemotherapy-induced increase in CD47 expression in epithelial ovarian cancer.

Epithelial ovarian cancer (EOC) remains the most lethal gynecological malignancy with limited treatment options. CD47 is a critical immune checkpoint for tumor immune evasion and has been targeted in various clinical trials. This study aimed to assess the impact of chemotherapy on CD47 expression in EOC in order to determine the potential and optimal timing of CD47-targeted therapy in ovarian cancer. We analyzed the expression of CD47 in ovarian cancer and the effect of chemotherapy on the expression of CD47 in ovarian cancer tissues. Furthermore, we investigated the effect of chemotherapy on the expression of CD47 in ovarian cancer cells. CD47 expression was examined using immunohistochemistry (IHC) of specimens from 78 patients with EOC who underwent neoadjuvant chemotherapy (NACT) and interval debulking surgery (IDS) with paired tissue specimens obtained before and after NACT. A retrospective review of the medical records was conducted to correlate demographic and survival data. Subsequently, we employed reverse transcription quantitative polymerase chain reaction (RT-qPCR) and flow cytometry analysis to examine and compare CD47 expression across human ovarian surface epithelial cell line (HOSE), SKOV3, and ES2 cells and to characterize the changes in CD47 expression in SKOV3 and ES2 cells after cisplatin treatment. CD47 expression was observed in 63 out of 78 (80.8%) cases before NACT. The expression of CD47 was not associated with the clinicopathological characteristics or the prognosis of patients with EOC. After three cancer specimens were excluded due to the absence of cancer cells following NACT, Wilcoxon exact tests of 75 pairs of matched specimens indicated that the expression of CD47 increased after chemotherapy (P=0.006). CD47 was expressed at varying levels in HOSE ovarian epithelial cells and SKOV3 and ES2 ovarian cancer cells. Notably, the CD47 messenger RNA (mRNA) expression of HOSE cells was observed to be lower than that of the SKOV3 and ES2 ovarian cancer cells (P<0.001). Following treatment with cisplatin, RT-qPCR indicated an increase in CD47 mRNA expression in SKOV3 and ES2 cells (P<0.001). Flow cytometry revealed a notable elevation in the cell surface CD47 protein mean fluorescence intensity of cisplatin-treated SKOV3 and ES2 cells (P<0.001). CD47 is highly expressed in ovarian cancer, and NACT increases the expression of CD47, which may contribute to tumor immune evasion. It is possible that platinum-based chemotherapy may result in elevated CD47 mRNA expression and cell surface CD47 protein expression.

Association of CTLA-4 (AT)n Variants in Basal Cell Carcinoma and Squamous Cell Carcinoma Patients from Western Mexico.

The incidence of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) is constantly increasing, becoming a significant health problem. CTLA-4 is a critical immune checkpoint, and it has been suggested that a variant of variable-number tandem repeat in the 3'-UTR of its gene, known as (AT)n, may be associated with a higher susceptibility to some cancers; however, little is known about genetic variants of the CTLA-4 gene in NMSC. To establish the association of this genetic variant in the CTLA-4 gene with the susceptibility of NMSC carcinogenesis in the Western Mexican population, samples from 150 BCC patients, 150 SCC patients, and 150 healthy individuals as the reference group (RG) were analyzed by endpoint PCR, followed by electrophoresis to genotype the samples. We found that the short-repeat 104/104 bp genotype may be a risk factor for BBC carcinogens (OR = 2.92, p = 0.03), whereas the long-repeat 106/106 bp genotype may be a protective factor for both BCC (OR = 0.13, p = 0.01) and SCC (OR = 0.32, p = 0.01) susceptibility. Our results show that in the Western Mexican population, long-repeat (AT)n variants in the CTLA-4 gene are associated with a protective factor in BCC and SCC. In contrast, short repeats are associated with a risk factor.

Long‐Term Storage Stable Vesicle‐Like Nanoparticles of Lipid and Polymer for siRNA and mRNA‐Mediated Cancer Immunotherapy

AbstractRNA‐based therapeutics have emerged as a promising strategy for cancer immunotherapy, encompassing the silencing of immune checkpoint genes, chimeric antigen receptor T (CAR‐T) cell production, and antitumor vaccines. Despite their tremendous potential, the urgent need for the development of clinically applicable delivery systems remains paramount. In this study, vesicle‐like nanoparticles (VNPs) are devised using clinically approved amphiphilic polymers and lipids as the delivery system for siRNA and mRNA. Through meticulous formulation adjustments of cationic lipids and ionizable lipids, a VNP formulation with exceptional transfection efficiency is identified. Notably, the VNPs maintained their remarkable transfection efficiency even after 6 months of storage. When loaded with siPD‐L1 and siCD47, these VNPs effectively silenced two critical immune checkpoint genes, enabling successful cancer immunotherapy. Moreover, when employed as a delivery system for mRNA vaccines, the VNPs induced a robust population of antigen‐specific CD8+ T cells in immunized mice. This led to the successful suppression of tumor growth (5 out of 8 subjects becoming tumor‐free) and nearly complete inhibition of lung metastasis. In summary, this lipid‐ and polymer‐based VNPs offer a long shelf life, excellent loading and transfection efficiency, versatility for various RNA types, and hold great promise as a delivery system for clinical applications.

Tryptophan deficiency induced by indoleamine 2,3-dioxygenase 1 results in glucose transporter 1-dependent promotion of aerobic glycolysis in pancreatic cancer.

Indoleamine 2,3-dioxygenase 1 (IDO1), the key enzyme in the catabolism of the essential amino acid tryptophan (Trp) through kynurenine pathway, induces immune tolerance and is considered as a critical immune checkpoint, but its impacts as a metabolism enzyme on glucose and lipid metabolism are overlooked. We aim to clarify the potential role of IDO1 in aerobic glycolysis in pancreatic cancer (PC). Analysis of database revealed the positive correlation in PC between the expressions of IDO1 and genes encoding important glycolytic enzyme hexokinase 2 (HK2), pyruvate kinase (PK), lactate dehydrogenase A (LDHA) and glucose transporter 1 (GLUT1). It was found that IDO1 could modulate glycolysis and glucose uptake in PC cells, Trp deficiency caused by IDO1 overexpression enhanced glucose uptake by stimulating GLUT1 translocation to the plasma membrane of PC cells. Besides, Trp deficiency caused by IDO1 overexpression suppressed the apoptosis of PC cells via promoting glycolysis, which reveals the presence of IDO1-glycolysis-apoptosis axis in PC. IDO1 inhibitors could inhibit glycolysis, promote apoptosis, and exhibit robust therapeutic efficacy when combined with GLUT1 inhibitor in PC mice. Our study reveals the function of IDO1 in the glucose metabolism of PC and provides new insights into the therapeutic strategy for PC.

Abstract 7528: Coordinated regulation of critical immune checkpoint proteins by the integrated stress response (ISR) pathway in lung cancer

Abstract Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related deaths worldwide. Despite recent advances, high rates of recurrence highlight the need for novel treatment options. Groundbreaking discoveries in identifying and exploiting the PD-1/PD-L1 (Programmed Death 1/Programmed Death Ligand 1) immune checkpoint have resulted in the approval of monoclonal antibodies that disrupt this interaction as a first-line therapy for lung cancer patients. However, only ~20% of NSCLC patients benefit from checkpoint blockade. A critical question remains as to what mechanisms facilitate resistance to PD-1/PD-L1 therapy and whether other immune checkpoints or pathways can be pursued clinically in combination with this therapy. The integrated stress response (ISR) pathway represents an emerging therapeutic vulnerability. The ISR is a generalized response to maintain cellular homeostasis, and is known to be activated by hypoxia, heme deprivation, amino acid starvation, and oncogenic activation. We previously demonstrated that ISR activation potently induces PD-L1 in NSCLC and suppression of anti-tumor immunity (Suresh et al, Nature Cancer, 2020). We discovered that ISR pathway activation enhances PD-L1 translation through the bypass of inhibitory upstream open reading frames (uORFs) in the PD-L1 5' UTR and a mechanistic link to the translation initiation factor eIF5B. Our latest studies demonstrate that the immune checkpoint protein, CD155 (Cluster of Differentiation 155), is induced by ISR activation. We find that both PD-L1 and CD155 are induced by multiple arms of the ISR pathway, and CD155 harbors inhibitory uORFs in its 5' UTR. Importantly, we observed a significant correlation between PD-L1 and CD155 expression in a panel of primary human lung adenocarcinomas. We further demonstrated that ISR activation inhibits T cell function in vitro and promotes tumor growth in the CMT167 syngeneic mouse model. Analysis of immune cell infiltration using mass cytometry in this in vivo model is ongoing. Currently, we are determining the extent to which ISR inhibition suppresses tumorigenesis by promoting anti-tumor immunity and whether this may synergize with existing immune checkpoint therapies. Overall, these studies will set the stage for determining whether inhibition of the ISR pathway alone or in combination with immune checkpoint blockade will benefit lung cancer patients. Our studies may also lead to new therapeutic approaches to trigger anti-cancer immune responses and improve current strategies. Citation Format: Shayna Elizabeth Thomas-Jardin, Shruthy Suresh, Cheryl Lewis, Chul Ahn, Bret M. Evers, John D. Minna, Kathryn A. O'Donnell. Coordinated regulation of critical immune checkpoint proteins by the integrated stress response (ISR) pathway in lung cancer [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 7528.

Abstract 2635: An epigenetic regulation targeting inhibitory receptors and attenuates CD8 T cell exhaustion in breast cancer

Abstract T cell exhaustion is a state of dysfunctional T cell response characterized by prolonged antigen exposure and diminished effector functions, a significant cause of tumor tolerance, and poor response to immune checkpoint blockade (ICB) therapy. T cell exhaustion is a highly dynamic process involved with a network of genetic and epigenetic regulation that program the T cell functions. Epigenetic regulation by microRNAs targets multiple genes involved in T cell function and is expected to be a major contributor to the functional programming of tumor-associated T cells. However, the underlying causal mechanisms remain to be determined. Here, we show that the microRNA miR-379-5p is a critical epigenetic regulator for promoting T cell function and suppressing exhaustion induced by chronic stimulation. The microRNA is identified by integrating bioinformatic interrogation of the miRNA databases cross-referencing with the TCGA database for genes involved in T cell functioning and their correlation with clinical outcomes, coupled with molecular profiling of miRNAs in experimental T exhaustion. Notably, the expression levels of miR-379-5p in tumor tissues, which encompass cancer cells and the surrounding stromal components, including immune cells, are closely associated with favorable prognosis of various cancer types. Further molecular and cellular characterization of miR-379-5p entailing cell culture, animal models, and patient-derived tumor organoids shows that it exerts suppressive effects by targeting specific sequences in the 3’ untranslated region (UTR) of critical immune checkpoint genes in T cells, thereby enhances the effector functions of cytotoxic T cells for tumor clearance. Ectopic expression of miR-379-5p shifts the evolution of primary T cells toward memory-like effector cells while silencing miR-379-5p induces exhaustion and abrogates the cytotoxic activity of primary T cells. We further demonstrate that transcriptional downregulation of miR-379-5p in T cells by a nuclear receptor transcription factor which is responsible for initiating the exhausting process impairs the tumor suppression function of T cells. Our studies indicate that miR-379-5p can function as a tumor suppressor by protecting T cells from exhaustion and bears the potential for developing novel strategies to improve the response to ICB therapy in breast cancer. Citation Format: You-Zhe Lin, Wan-Rong Wu, Feng-Chi Chung, Yi-Chun Shen, Chuan-Chun Lee, Hong-Wei Li, Guang-Jan Lin, Wei-Chung Chengx, Shao-Chun Wang. An epigenetic regulation targeting inhibitory receptors and attenuates CD8 T cell exhaustion in breast cancer [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 2635.

Tumor cell senescence-induced macrophage CD73 expression is a critical metabolic immune checkpoint in the aging tumor microenvironment.

Background: The role of senescent cells in the tumor microenvironment (TME) is usually bilateral, and diverse therapeutic approaches, such as radiotherapy and chemotherapy, can induce cellular senescence. Cellular interactions are widespread in the TME, and tumor cells reprogram immune cells metabolically by producing metabolites. However, how senescent cells remodel the metabolism of TME remains unclear. This study aimed to explore precise targets to enhance senescent cells-induced anti-tumor immunity from a metabolic perspective. Methods: The in vivo senescence model was induced by 8 Gy×3 radiotherapy or cisplatin chemotherapy, and the in vitro model was induced by 10 Gy-irradiation or cisplatin treatment. Metabonomic analysis and ELISA assay on tumor interstitial fluid were performed for metabolites screening. Marker expression and immune cell infiltration in the TME were analyzed by flow cytometry. Cell co-culture system and senescence-conditioned medium were used for crosstalk validation in vitro. RNA sequencing and rescue experiments were conducted for mechanism excavation. Immunofluorescence staining and single-cell transcriptome profiling analysis were performed for clinical validation. Results: We innovatively reveal the metabolic landscape of the senescent TME, characterized with the elevation of adenosine. It is attributed to the senescent tumor cell-induced CD73 upregulation of tumor-associated macrophages (TAMs). CD73 expression in TAMs is evoked by SASP-related pro-inflammatory cytokines, especially IL-6, and regulated by JAK/STAT3 pathway. Consistently, a positive correlation between tumor cells senescence and TAMs CD73 expression is identified in lung cancer clinical specimens and databases. Lastly, blocking CD73 in a senescent background suppresses tumors and activates CD8+ T cell-mediated antitumor immunity. Conclusions: TAMs expressed CD73 contributes significantly to the adenosine accumulation in the senescent TME, suggesting targeting CD73 is a novel synergistic anti-tumor strategy in the aging microenvironment.

PDL1 in Cancer: A Remarkable Mile Stone Achieved

PD-1, or programmed cell death protein 1, is indeed a critical immune checkpoint receptor expressed on activated T lymphocytes, including tumor-specific CD4+ helper and CD8+ killer T cells. Originally, PD-1 was identified as a regulator of cell death, but its role in immune regulation has since been recognized as crucial in the context of cancer immunotherapy.

Optimization of lipid assisted polymeric nanoparticles for siRNA delivery and cancer immunotherapy.

To date, five siRNA-based medications have received clinical approval and have demonstrated remarkable therapeutic efficacy in treating various diseases. However, their application has been predominantly limited to liver-specific diseases due to constraints in siRNA delivery capabilities. In this study, we have developed a siRNA delivery system utilizing clinically approved mPEG-b-PLGA, a cationic lipid, and an ionizable lipid. We optimized this system by carefully adjusting their mass ratios, resulting in highly efficient gene silencing. Furthermore, the optimized nanoparticle formulation, which encapsulates siRNA targeting CD47, induces a robust immune response. This response effectively suppresses the progression of melanoma tumors by blocking this critical immune checkpoint.

Antagonizing Vasoactive Intestinal Peptide (VIP) Receptors on CAR T Cells Improves Efficacy and Persistence

Vasoactive intestinal peptide (VIP) is an emerging checkpoint pathway for T cell function 1. VIP is expressed by both T cells 2,3 and tumor cells 1 and is upregulated during TCR activation 1,4,5. Augmentation of the VIP/VIPR axis during expansion of primary human T cells enhances less differentiated T cell phenotypes, anti-tumor cytotoxicity, and in vivo persistence 6. In this work, we elucidate the mechanisms by which the VIP/VIPR axis is a critical and targetable immune checkpoint pathway for chimeric antigen receptor (CAR) T cell therapy. By engineering CAR T cells to secrete novel and potent VIPR antagonistic peptides, these cells can overcome the immunosuppression of VIP-rich tumor microenvironments. First, we demonstrated that VIP suppresses CAR T cell function as evident by reduced expansion with exogenous VIP supplementation, which can be rescued by the addition of VIPRa peptides. The VIP/VIPR axis is relevant to CAR T cell signaling as these cells produce VIP after antigen stimulation and upregulate VIPR expression. In fact, polyfunctionality and cytotoxic killing is enhanced by VIPR knockout of CAR T cells. Together, these results demonstrate the critical role of the VIP/VIPR axis in CAR T cell function. To harness this axis, CAR T cells were engineered to secrete VIPRa peptides (VIPRa CAR T) to provide continuous and localized delivery of VIPRa peptides. Continuously delivered VIPR antagonism increases the viability and proportions of less-differentiated and less-exhaustive phenotypes of CAR T cells at baseline. Functionally, VIPRa CAR T cells have a proliferative advantage and enhanced activation compared to parental CAR T cells. RNA sequencing was performed on VIPRa CAR T cells before and after antigen-stimulation to illuminate in-depth phenotypic and functional differences compared parental CAR T cells. Finally, these novel CAR T cells were tested in xenograft and syngeneic mouse models. VIPRa CAR T cells show improved tumor control and persistence as evidence long-lived circulating cells in the peripheral blood. To validate the clinical relevance of this target for CAR T therapy, patient-derived xenograft (PDX) pancreatic tumors were assayed to show robust expression of VIP. VIPRa CAR T cells significantly reduced tumor burden and improved survival in PDX tumor-bearing mice. Collectively, this data demonstrates that targeting VIP is a novel and successful approach to improving CAR T cell anti-tumor efficacy. VIPR antagonism enhances initial CAR T cell phenotypes and function, which has the potential to improve CAR T cell therapy for a variety of tumor types. The mechanisms by which CAR T cell-mediated delivery of VIPRa peptides can modulate tumor microenvironments in a syngeneic model are currently being evaluated. VIPRa CAR T cells are a uniquely improved cellular therapy capable of enhanced anti-tumor function against clinically relevant tumors.

Construction and validation of a PANoptosis-related lncRNA signature for predicting prognosis and targeted drug response in thyroid cancer.

Thyroid cancer (TC) is the most prevalent malignancy of the endocrine system. PANoptosis, a newly discovered cell death pathway, is of interest in tumor research. However, the relationship between PANoptosis-related lncRNAs (PRlncRNAs) and TC remains unclear. The study aimed to develop a prognostic model based on PRlncRNAs in TC. Gene expression data of PANoptosis-associated genes and clinical information on TC from The Cancer Genome Atlas (TCGA) database were analyzed by Pearson correlation analysis, univariate/multivariate Cox analysis, and Lasso Cox regression analysis. A PRlncRNA signature was constructed and used to develop a nomogram to predict overall survival (OS). We further explored the correlation between the risk score and tumor immune microenvironment, immune checkpoints, and drug sensitivity. Moreover, we verified the expression and biological function of lncRNAs in TC cell lines. Finally, seven PRlncRNAs were used to construct a prognostic model for predicting the OS of TC patients. We found that the risk score was associated with the tumor microenvironment (TME) and the expression of critical immune checkpoints. In addition, we screened for drugs that high- or low-risk TC groups might be sensitive to. Quantitative real-time polymerase chain reaction (qRT-PCR) results showed differential expression of four PRlncRNAs (GAPLINC, IDI2-AS1, LINC02154, and RBPMS-AS1) between tumor and normal tissues. Besides, a GEO database (GSE33630) was used to verify the expression differences of PRLncRNAs in THCA tissues and normal tissues. Finally, RBPMS-AS1 was found to inhibit the proliferation and migration of TC cells. In conclusion, we developed a PANoptosis-related lncRNA prognostic risk model that offers a comprehensive understanding of TME status in patients with TC and establishes a foundation for the choice of sensitive medications and immunotherapy.

Emerging role of deubiquitination modifications of programmed death-ligand 1 in cancer immunotherapy.

Immune evasion is essential for carcinogenesis and cancer progression. Programmed death-ligand 1 (PD-L1), a critical immune checkpoint molecule, interacts with programmed death receptor-1 (PD-1) on immune cells to suppress anti-tumor immune responses. In the past decade, antibodies targeting PD-1/PD-L1 have tremendously altered cancer treatment paradigms. Post-translational modifications have been reported as key regulators of PD-L1 expression. Among these modifications, ubiquitination and deubiquitination are reversible processes that dynamically control protein degradation and stabilization. Deubiquitinating enzymes (DUBs) are responsible for deubiquitination and have emerged as crucial players in tumor growth, progression, and immune evasion. Recently, studies have highlighted the participation of DUBs in deubiquitinating PD-L1 and modulating its expression. Here, we review the recent developments in deubiquitination modifications of PD-L1 and focus on the underlying mechanisms and effects on anti-tumor immunity.

PD-L1 methylation restricts PD-L1/PD-1 interactions to control cancer immune surveillance.

Immune checkpoint inhibitors targeting programmed cell death protein 1 (PD-1) or programmed cell death 1 ligand 1 (PD-L1) have enabled some patients with cancer to experience durable, complete treatment responses; however, reliable anti-PD-(L)1 treatment response biomarkers are lacking. Our research found that PD-L1 K162 was methylated by SETD7 and demethylated by LSD2. Furthermore, PD-L1 K162 methylation controlled the PD-1/PD-L1 interaction and obviously enhanced the suppression of T cell activity controlling cancer immune surveillance. We demonstrated that PD-L1 hypermethylation was the key mechanism for anti-PD-L1 therapy resistance, investigated that PD-L1 K162 methylation was a negative predictive marker for anti-PD-1 treatment in patients with non-small cell lung cancer, and showed that the PD-L1 K162 methylation:PD-L1 ratio was a more accurate biomarker for predicting anti-PD-(L)1 therapy sensitivity. These findings provide insights into the regulation of the PD-1/PD-L1 pathway, identify a modification of this critical immune checkpoint, and highlight a predictive biomarker of the response to PD-1/PD-L1 blockade therapy.

A novel autophagy-related gene signature associated with prognosis and immune microenvironment in ovarian cancer

Ovarian cancer (OV), the most fatal gynecological malignance worldwide, has high recurrence rates and poor prognosis. Recently, emerging evidence supports that autophagy, a highly regulated multi-step self-digestive process, plays an essential role in OV progression. Accordingly, we filtered 52 potential autophagy-related genes (ATGs) among the 6197 differentially expressed genes (DEGs) identified in TCGA-OV samples (n = 372) and normal controls (n = 180). Based on the LASSO-Cox analysis, we distinguished a 2-gene prognostic signature, namely FOXO1 and CASP8, with promising prognostic value (p-value < 0.001). Together with corresponding clinical features, we constructed a nomogram model for 1-year, 2-year, and 3-year survival, which was validated in both in training (TCGA-OV, p-value < 0.001) and validation (ICGC-OV, p-value = 0.030) cohorts. Interestingly, we evaluated the immune infiltration landscape through the CIBERSORT algorithm, which indicated the upregulation of 5 immune cells, including CD8 + T cells, Tregs, and Macrophages M2, and high expression of critical immune checkpoints (CTLA4, HAVCR2, PDCD1LG2, and TIGIT) in high-risk group. Stepwise, high-risk group exhibited better sensitivity towards chemotherapies of Bleomycin, Sorafenib, Veliparib, and Vinblastine, though less sensitive to immunotherapy. Especially, based on the IHC of tissue microarrays among 125 patients in our institution, we demonstrated that aberrant upregulation of FOXO1 in OV was related to metastasis and poor prognosis. Moreover, FOXO1 could significantly promote tumor invasiveness, migration, and proliferation in OV cell lines, which was assessed through the Transwell, wound-healing, and CCK-8 assay, respectively. Briefly, the autophagy-related signature was a reliable tool to evaluate immune responses and predict prognosis in the realm of OV precision medicine.

CD73 Is a Critical Immune Checkpoint in a Molecular Subtype of Pancreatic Cancer

Molecular stratification of patients with pancreatic ductal adenocarcinoma (PDAC) has the potential to guide clinical decision-making for therapeutic intervention. Investigating mechanisms by which different molecular subtypes of PDAC form and progress will improve patient responses to existing therapies and aid in identifying new, more specific therapeutic approaches. In this issue of Cancer Research, Faraoni and colleagues identified CD73/Nt5e-generated adenosine as a mechanism of immunosuppression specifically in pancreatic ductal-derived basal/squamous-type PDAC. Using genetically engineered mouse models targeting key genetic mutations to pancreatic acinar or ductal cells and an array of experimental and computational biology approaches, the authors found that adenosine signaling through receptor ADORA2B induces immunosuppression and tumor progression in ductal cell-derived tumors. These data demonstrate how molecular stratification of PDAC in combination with targeted approaches may enhance patient responses to therapy in this deadly cancer. See related article by Faraoni et al., p. 1111.