PD-1+ regulatory T cells amplified by PD-1 blockade promote hyperprogression of cancer

Construction and validation of a regulatory T cells-based classification of renal cell carcinoma: an integrated bioinformatic analysis and clinical cohort study

PURPOSE

Renal cell carcinoma (RCC), exhibiting remarkable heterogeneity, can be highly infiltrated by regulatory T cells (Tregs). However, the relationship between Treg and the heterogeneity of RCC remains to be explored.

METHODS

We acquired single-cell RNA-seq profiles and 537 bulk RNA-seq profiles of TCGA-KIRC cohort. Through clustering, monocle2 pseudotime and prognostic analyses, we identified Treg states-related prognostic genes (TSRPGs), then constructing the RCC Treg states-related prognostic classification (RCC-TSC). We also explored its prognostic significance and multi-omics landmarks. Additionally, we utilized correlation analysis to establish regulatory networks, and predicted candidate inhibitors. More importantly, in Xinhua cohort of 370 patients with kidney neoplasm, we used immunohistochemical (IHC) staining for classification, then employing statistical analyses including Chi-square tests and multivariate Cox proportional hazards regression analysis to explore its clinical relevance.

RESULTS

We defined 44 TSRPGs in four different monocle states, and identified high immune infiltration RCC (HIRC, LAG3+, Mki67+) as the highly exhausted subtype with the worst prognosis in RCC-TSC (p < 0.001). BATF-LAG3-immune cells axis might be its underlying metastasis-related mechanism. Immunotherapy and inhibitors including sunitinib potentially conferred best therapeutic effects for HIRC. Furthermore, we successfully validated HIRC subtype as an independent prognostic factor within the Xinhua cohort (OS, HR = 16.68, 95% CI = 1.88-148.1, p = 0.011; PFS, HR = 4.43, 95% CI = 1.55-12.6, p = 0.005).

CONCLUSION

Through integrated bioinformatics analysis and a large-sample retrospective clinical study, we successfully established RCC-TSC and a diagnostic kit, which could stratify RCC patients with different prognosis and to guide personalized treatment.

Modulating immune cells within pancreatic ductal adenocarcinoma via nanomedicine

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy characterized by a dense extracellular matrix (ECM) and a uniquely immunosuppressive tumor microenvironment (TME), which together form a formidable barrier that hinders deep drug penetration, limiting the efficacy of conventional therapies and leading to poor patient outcomes. Nanocarrier technology emerges as a promising strategy to improve treatment efficacy in PDAC. Nanocarriers can not only improve drug penetration through their adjustable physicochemical properties but also effectively regulate immune cell function in pancreatic cancer TME and promote anti-tumor immune response. This mini-review discusses the effects of nanocarriers on the immune microenvironment of PDAC, analyzing their mechanisms in modulating immune cells, overcoming ECM barriers, and reshaping the TME.

Targeting SAMD1 enhances the effect of anti-PD-1 plus lenvatinib therapy in hepatocellular carcinoma by increasing ferroptosis sensitivity and immune response

BACKGROUND

Combination therapy of anti-PD-1 plus lenvatinib has shown effective anti-tumour effects for unresectable hepatocellular carcinoma (HCC), but the overall prognosis of HCC is still unsatisfactory. Elucidating the molecular mechanism underlying HCC progression contributes to develop new effective treatment in order to enhances the response of anti-PD-1 plus lenvatinib therapy and improve the patients prognosis.

METHOD AND RESULTS

Here, we reported that targeting SAMD1 in HCC cells via small interference RNA-containing ZIF-90@HA (ATP/acid-responsive) Nanoparticles (ZIF-90@siRNA@HA NPs, ZSH NPs) significantly enhanced the anti-tumour effects of anti-PD-1 plus lenvatinib in vivo. Targeting SAMD1 in HCC cells not only increased cellular ROS abundance by inhibiting glycolysis and enhancing oxidative phosphorylation (OXPHOS) to increase ferroptosis sensitivity, but also inhibited the expression of CCL28, thereby reducing the recruitment of Treg cells, and improving the immunosuppression of tumour microenvironment. Mechanistically, SAMD1 suppression inhibits the expression of NUAK2 via Hippo pathway, thereby decreasing the phosphorylation of PFKP Ser386 and promoting the ubiquitination degradation of PFKP in HCC. Further study demonstrated that SAMD1 inhibition increased the expression of ITIH5 by regulating H3K4me3 demethylation at the ITIH5 promoter and then regulates Hippo pathway.

CONCLUSIONS

Our study revealed the potential application of targeting SAMD1 in HCC treatment by enhancing ferroptosis sensitivity and immune response.

Regulatory T Cells in Tumor Microenvironment: Therapeutic Approaches and Clinical Implications

Regulatory T cells (Tregs), previously referred to as suppressor T cells, represent a distinct subset of CD4+ T cells that are uniquely specialized for immune suppression. They are characterized by the constitutive expression of the transcription factor FoxP3 in their nuclei, along with CD25 (the IL-2 receptor α-chain) and CTLA-4 on their cell surface. Tregs not only restrict natural killer cell-mediated cytotoxicity but also inhibit the proliferation of CD4+ and CD8+ T-cells and suppress interferon-γ secretion by immune cells, ultimately impairing an effective antitumor immune response. Treg cells are widely recognized as a significant barrier to the effectiveness of tumor immunotherapy in clinical settings. Extensive research has consistently shown that Treg cells play a pivotal role in facilitating tumor initiation and progression. Conversely, the depletion of Treg cells has been linked to a marked delay in tumor growth and development.

TIGIT blockade increases efficacy of PD-1 blockade combined with radiation therapy in triple-negative breast cancer model

BACKGROUND AND PURPOSE

T-cell immunoreceptor with Ig and ITIM domains (TIGIT) suppresses functions of CD8+ T cells, and radiation therapy (RT) induces stimulation of regulatory T cells (Tregs), thereby limiting antitumor efficacy. This study aims to investigate the role of TIGIT in the immunosuppressive tumor environment and evaluate the potential of TIGIT blockade (αTIGIT) to enhance antitumor immune responses.

METHODS

We analyzed public transcriptomic data to identify the expression patterns of TIGIT on T cells in breast cancer and its prognostic impact. In addition, a murine TNBC model was utilized to evaluate the effects of αPD-1, local RT, and αTIGIT. T cells in tumors, tumor-draining lymph nodes (TdLNs), and the spleen were analyzed to assess the antitumor immune responses upon the treatments.

RESULTS

The analysis revealed that TIGIT is predominantly expressed on T cells within breast cancer, and the expression of TIGIT was associated with poor outcomes in TNBC patients. In the murine model, the combination of αPD-1 and RT increased TIGIT+CD226+CD8+ TILs, which are crucial for the efficacy of αTIGIT. Adding αTIGIT to αPD-1 and RT (αPD-1/RT) resulted in a synergistic antitumor effect, which was accompanied by increased infiltration of CD8+ TILs in both irradiated and nonirradiated tumors by the triple combination therapy compared to αPD-1/RT. The triple combination therapy also resulted in a less exhausted phenotype among CD8+ TILs and increased the proliferation of splenic CD8+ T cells. Moreover, αTIGIT significantly reduced Tregs in tumors, TdLNs, and the spleen when combined with αPD-1/RT.

CONCLUSION

αTIGIT exhibits synergistic effects when added to αPD-1/RT by increasing the infiltration and activation of CD8+ TILs while reducing Tregs. The study suggests that αTIGIT could be an effective strategy to enhance the antitumor efficacy of αPD-1 and RT in TNBC.

Pharmacological inhibition of tyrosine protein-kinase 2 reduces islet inflammation and delays type 1 diabetes onset in mice

BACKGROUND

Tyrosine protein-kinase 2 (TYK2) mediates inflammatory signalling through multiple cytokines, including interferon-α (IFNα), interleukin (IL)-12, and IL-23. TYK2 missense mutations protect against type 1 diabetes (T1D), and inhibition of TYK2 shows promise in other autoimmune conditions.

METHODS

We evaluated the effects of specific TYK2 inhibitors (TYK2is) in pre-clinical models of T1D, including human β cells, cadaveric islets, iPSC-derived islets, and mouse models.

FINDINGS

In vitro studies showed that TYK2is prevented IFNα-induced β cell HLA class I up-regulation, endoplasmic reticulum stress, and chemokine production. In co-culture studies, pre-treatment of β cells with TYK2i prevented IFNα-induced antigenic peptide presentation and alloreactive and autoreactive T cell degranulation. In vivo administration of BMS-986202 in two mouse models of T1D (RIP-LCMV-GP and NOD mice) reduced systemic and tissue-localised inflammation, prevented β cell death, and delayed T1D onset. Transcriptional phenotyping of pancreatic islets, pancreatic lymph nodes, and spleen highlighted a role for TYK2 inhibition in modulating signalling pathways associated with inflammation, translational control, stress signalling, secretory function, immunity, and diabetes. Additionally, TYK2i treatment changed the composition of innate and adaptive immune cell populations in the blood and disease target tissues.

INTERPRETATION

These findings indicate that TYK2i has beneficial effects on both the immune and endocrine compartments in models of T1D, thus supporting a path forward for testing TYK2is in human T1D.

FUNDING

This work was supported by the National Institutes of Health (NIH), Veteran Affairs (VA), Breakthrough T1D, and gifts from the Sigma Beta Sorority, the Ball Brothers Foundation, and the George and Frances Ball Foundation.

High Antigenicity for Treg Cells Confers Resistance to PD-1 Blockade Therapy via High PD-1 Expression in Treg Cells

Regulatory T (Treg) cells have an immunosuppressive function, and programmed death-1 (PD-1)-expressing Treg cells reportedly induce resistance to PD-1 blockade therapies through their reactivation. However, the effects of antigenicity on PD-1 expression in Treg cells and the resistance to PD-1 blockade therapy remain unclear. Here, we show that Treg cells gain high PD-1 expression through an antigen with high antigenicity. Additionally, tumors with high antigenicity for Treg cells were resistant to PD-1 blockade in vivo due to PD-1+ Treg-cell infiltration. Because such PD-1+ Treg cells have high cytotoxic T lymphocyte antigen (CTLA)-4 expression, resistance could be overcome by combination with an anti-CTLA-4 monoclonal antibody (mAb). Patients who responded to combination therapy with anti-PD-1 and anti-CTLA-4 mAbs sequentially after primary resistance to PD-1 blockade monotherapy showed high Treg cell infiltration. We propose that the high antigenicity of Treg cells confers resistance to PD-1 blockade therapy via high PD-1 expression in Treg cells, which can be overcome by combination therapy with an anti-CTLA-4 mAb.

Hyperprogression of brain metastases following initiation of immune checkpoint inhibitors

PURPOSE

Immune checkpoint inhibitors (ICI) are increasingly being administered to cancer patients, including those with brain metastases (BMs). However, in a subset of cancer patients, ICI have shown to paradoxically accelerate tumor growth. This phenomenon is known as hyperprogressive disease (HPD). The aim of this study is to investigate the occurrence of HPD following initiation of ICI in BM patients.

METHODS

We retrospectively reviewed the charts of 60 surgically treated patients with BMs from non-small cell lung cancer or melanoma who were administered ICI at the Brigham and Women's Hospital, Boston between July 2008 and July 2018. BM tumor volumes before and after initiation of ICI were collected. HPD was defined as a 'post-immunotherapy' tumor growth rate (TGR) > 2 times 'pre-immunotherapy' TGR within three months following initiation of ICI.

RESULTS

Among the 25 included patients treated with ICI, five patients showed HPD with an increase of post-immunotherapy TGR ranging from 4.9 to 207.7 times the pre-immunotherapy TGR. The median survival after initiation of ICI was was 8.0 months in the HPD cases and 13 months in the non-HPD patients.

CONCLUSION

HPD occurred in about 20% of BM patients receiving ICI. More research is necessary to prospectively analyze the occurrence of HPD and identify predictive factors for HPD in BM patients.

Nivolumab plus chemotherapy or ipilimumab in gastroesophageal cancer: exploratory biomarker analyses of a randomized phase 3 trial

First-line nivolumab-plus-chemotherapy demonstrated superior overall survival (OS) and progression-free survival versus chemotherapy for advanced gastroesophageal adenocarcinoma with programmed death ligand 1 combined positive score ≥ 5, meeting both primary end points of the randomized phase 3 CheckMate 649 trial. Nivolumab-plus-ipilimumab provided durable responses and higher survival rates versus chemotherapy; however, the prespecified OS significance boundary was not met. To identify biomarkers predictive of differential efficacy outcomes, post hoc exploratory analyses were performed using whole-exome sequencing and RNA sequencing. Nivolumab-based therapies demonstrated improved efficacy versus chemotherapy in hypermutated and, to a lesser degree, Epstein-Barr virus-positive tumors compared with chromosomally unstable and genomically stable tumors. Within the KRAS-altered subgroup, only patients treated with nivolumab-plus-chemotherapy demonstrated improved OS benefit versus chemotherapy. Low stroma gene expression signature scores were associated with OS benefit with nivolumab-based regimens; high regulatory T cell signatures were associated with OS benefit only with nivolumab-plus-ipilimumab. Our analyses suggest that distinct and overlapping pathways contribute to the efficacy of nivolumab-based regimens in gastroesophageal adenocarcinoma.

Regulation of the CD8⁺ T cell and PDL1/PD1 axis in gastric cancer: Unraveling the molecular landscape

Gastric cancer (GC) remains a significant global health burden, mainly due to immune evasion mechanisms within its complex tumor microenvironment (TME). The interaction between CD8⁺ T cells and the PD1/PDL1 axis is central to these mechanisms. CD8⁺ T cells, key players in antitumor immunity, often exhibit impaired functionality in the GC TME, primarily due to PD1-mediated inhibitory signaling induced by PDL1 expressed on tumor and immune cells. Recent findings have elucidated intricate molecular interactions governing PD1 expression on CD8⁺ T cells and the modulation of PDL1 on tumor cells and immune cells by diverse signals such as cytokines, metabolic factors, and noncoding RNAs. While high PD1 expression typically indicates CD8⁺ T cell exhaustion and poor clinical outcomes, recent studies highlight scenarios where elevated PD1 levels correlate with preserved or enhanced T cell cytotoxic activity, suggesting nuanced regulatory pathways. Therapeutic strategies that disrupt PD1/PDL1 interactions, through checkpoint inhibitors or pharmacological modulation, have demonstrated potential in reactivating antitumor responses. However, resistance mechanisms, including altered antigen presentation, metabolic reprogramming, and immunosuppressive cell infiltration, continue to limit efficacy. Emerging combination therapies, biomarker-driven patient stratification, and novel targets like noncoding RNAs and exosomal PDL1 represent promising avenues to enhance treatment effectiveness. This review synthesizes current insights into the molecular regulation of CD8⁺ T cell functionality and the PD1/PDL1 axis, highlighting potential therapeutic strategies to restore antitumor immunity and improve patient outcomes in gastric cancer.

Exploring predictive biomarkers of efficacy and survival with nivolumab treatment for unresectable/recurrent esophageal squamous cell carcinoma

BACKGROUND

Programmed cell death protein-1 (PD-1) blockade has improved survival for patients with esophageal squamous cell carcinoma (ESCC), but response rates are low. Biomarkers to predict who will benefit from PD-1 blockade are urgently needed.

METHODS

This multicenter study involved 250 patients with recurrent/unresectable advanced ESCC receiving nivolumab as second- or later-line therapy. We assessed tumor-infiltrating T lymphocytes (TILs) and tertiary lymphoid structure (TLS) density using immunohistochemistry and hematoxylin/eosin staining in surgical specimens and pre-nivolumab endoscopic biopsies.

RESULTS

In surgical specimens, clinical response (vs. non-response) to nivolumab correlated significantly with CD8+ lymphocyte count (160 vs. 95.2 cells/field, P = 0.0494), CD8/Foxp3 ratio (6.52 vs. 2.72, P = 0.0053), and TLS density (0.21/mm2 vs. 0.10/mm2, P = 0.0005). In terms of overall survival, multivariate analysis identified CD8/Foxp3 ratio (hazard ratio [HR] = 1.83, P = 0.0050) and TLS density (HR = 1.67, P = 0.0171 as independent prognostic parameters in surgical specimens. Similarly, in endoscopic biopsies, clinical response (vs. non-response) to nivolumab correlated significantly with CD8+ counts (254 cells/mm2 vs. 124 cells/mm2, P = 0.0344), CCR8+ lymphocyte count (62.6 cells/mm2 vs. 140 cells/mm2, P = 0.0355), CD8/Foxp3 ratio (2.09 vs. 0.89, P = 0.040), and CD8/CCR8 ratio (2.34 vs. 0.89, P = 0.0020). Multivariate analysis also identified CD8/CCR8 ratio in endoscopic biopsies (HR = 1.66, P = 0.0313) as an independent prognostic parameter.

CONCLUSIONS

CD8+ and CCR8+ cell counts, CD8/Foxp3 and CD8/CCR8 ratios, and TLS density may be predictive biomarkers of therapeutic efficacy and survival with PD-1 blockade for ESCC.

Prognostic nutrition index reveals LAG3 in cytotoxic CD8+ T cells and MHC class II in gastric cancer cells

BACKGROUND

The prognostic nutrition index (PNI) has recently been highlighted as a predictor of immune checkpoint (IC) inhibitor efficacy in gastric cancer (GC). Although LAG3, an IC molecule, has gained considerable attention, its association with PNI remains unexplored.

MATERIALS AND METHODS

We retrospectively analyzed clinical data from 796 GC patients who underwent radical gastrectomy to identify which previously reported nutritional index had the greatest impact on prognosis. Single-cell RNA sequencing was performed on 38 GC tissues, and multiplex immunofluorescence staining was conducted on 59 GC tissues to evaluate the relationship between nutritional indices and IC molecule expression in cytotoxic CD8-positive T cells.

RESULTS

A low preoperative PNI was identified as the strongest predictor of poor prognosis among the nutritional indices in GC patients. The expression of not only PDCD1 (encoding PD1) but also LAG3 in cytotoxic CD8-positive T cells was significantly higher in GC with low PNI compared to those with high PNI. Among cytotoxic CD8-positive T cells, the proportion of LAG3-positive cells was greater than that of PDCD1-positive cells, particularly in GC with low PNI, and most LAG3-positive cells did not co-express PDCD1. Additionally, the expression of MHC class II, a ligand for LAG3, was higher in GC cells with high levels of epithelial-mesenchymal transition-related molecules in GC with low PNI compared to those with high PNI.

CONCLUSIONS

PNI can reflect LAG3 expression in cytotoxic CD8-positive T cells and MHC class II expression in GC cells.

Association of peripheral monocytic myeloid-derived suppressor cells with molecular subtypes in single-center endometrial cancer patients receiving carboplatin + paclitaxel/avelumab (MITO-END3 trial)

The MITO-END3 trial compared carboplatin and paclitaxel (CP) with avelumab plus carboplatin and paclitaxel (CPA) as first-line treatment in endometrial cancer (EC) patients and demonstrated a significant interaction between avelumab response and mismatch repair status. To investigate prognostic/predictive biomarker, 29 MITO-END3-EC patients were evaluated at pretreatment (B1) and at the end of CP/CPA treatment (B2) for peripheral myeloid-derived suppressor cells (MDSC) and Tregs. At B2, effector Tregs frequency was significantly higher in patients treated with CPA as compared to CP (p = 0.038). Both treatments (CP/CPA) induced significant decrease in peripheral M-MDSC (- 5.41%) in TCGA 2-MSI-high as compared to TCGA-category 4 tumors (p = 0.004). In accordance, both treatments induced M-MDSCs (+ 5.34%) in MSS patients as compared to MSI-high patients (p = 0.001). Moreover, in a subgroup of patients, primary tumors were highly infiltrated by M-MDSCs in MSS as compared to MSI-high ECs. A post hoc analysis displayed higher frequency of M-MDSCs (p = 0.020) and lower frequency of CD4+ (p < 0.005) at pretreatment in EC patients as compared to healthy donors. In conclusion, the peripheral evaluation of MDSCs and Tregs correlated with molecular features in EC treated with CP/CPA and may add insights in identifying EC patients responder to first-line chemo/chemo-immunotherapy.

ACVR2A attenuation impacts lactate production and hyperglycolytic conditions attracting regulatory T cells in hepatocellular carcinoma

Although ACVR2A mutations are prevalent in non-viral hepatocellular carcinomas (HCCs), the underlying mechanism remains unelucidated. Our molecular investigation reveals that ACVR2A impairment induces hyperglycolysis through the inactivation of the SMAD signaling pathway. Using syngeneic transplantation models and human clinical samples, we clarify that ACVR2A-deficient HCC cells produce and secrete lactate via the upregulation of lactate dehydrogenase A (LDHA) and monocarboxylate transporter 4 (MCT4) expression levels, which promotes regulatory T (Treg) cell accumulation and then acquires resistance to immune checkpoint inhibitors. Remarkably, genetic knockdown and pharmacological inhibition of MCT4 ameliorate the high-lactate milieu in ACVR2A-deficient HCC, resulting in the suppression of intratumoral Treg cell recruitment and the restoration of the sensitivity to PD-1 blockade. These findings furnish compelling evidence that lactate attenuates anti-tumor immunity and that therapeutics targeting this pathway present a promising strategy for mitigating immunotherapy resistance in ACVR2A-deficient HCC.

GSK-3 regulates CD4-CD8 cooperation needed to generate super-armed CD8+ cytolytic T cells against tumors

While immune checkpoint blockade (ICB) has revolutionized cancer treatment, the key T-cell signaling pathways responsible for its potency remain unclear. GSK-3 is an inhibitory kinase that is most active in resting T-cells. In this study, we demonstrate that GSK-3 facilitates PD-1 blockade, an effect seen by modulating CD4 T-cell help for CD8+ CTL responses against ICB resistant tumors. We show that GSK-3 controls metabolic reprogramming towards glycolysis and synergizes with PD-1 to induce a transcriptional program that reduces suppressive CD4+ Treg numbers while generating super-armed effector-memory CD8+ CTLs that express an unprecedented 7/9 granzymes from the genome. Crucially, we found that GSK-3 cooperates with PD-1 blockade to determine the dependency of CD8+ CTLs on help from CD4+ T-cells. Our study unravels a novel cooperative PD-1 blockade-dependent signaling pathway that potentiates CTL responses against tumors, offering a new strategy to overcome immunotherapy resistance by modulating CD4+ helper and CD8+ cytotoxic functions.

Significance

This study demonstrates for the first time that GSK-3 controls the crosstalk between CD4+ and CD8+ T cells, synergizing with anti-PD-1 therapy to overcome resistance to checkpoint blockade and to generate super-armed CD8+ effector cells in cancer immunotherapy. This newly uncovered GSK-3-dependent CD4-CD8 T-cell crosstalk mechanism presents a new approach to enhance anti-PD-1 immunotherapy.

Combination of anlotinib with immunotherapy enhanced both anti-angiogenesis and immune response in high-grade serous ovarian cancer

Background

High-grade serous ovarian cancer (HGSOC) poses significant treatment challenges due to frequent recurrence and resistance to conventional therapies. Combination of anlotinib with immunotherapy have showed promise in various cancers, but its impact on HGSOC remains to be fully elucidated.

Methods

A retrospective analysis was performed on 36 HGSOC patients treated with anlotinib-based therapies, including both monotherapy and combination treatment with anti-PD-L1/anti-PD-1 antibody (aPD-L1/aPD-1). Peripheral blood mononuclear cell-derived patient-derived xenograft (PBMC-PDX) model was established from drug-resistant recurrent HGSOC patient-derived tumor cells, and single-cell RNA sequencing (scRNA-seq) was conducted to dissect the TME following treatment with anlotinib, anlotinib + aPD-L1 and anlotinib + aPD-1.

Results

Clinical analysis revealed a disease control rate (DCR) of 71.43% for anlotinib monotherapy, which improved to 100% when combined with aPD-L1/aPD-1. In PBMC-PDX models, treatment evaluation showed that anlotinib decreased tumor volume, an effect further enhanced by its combination with aPD-L1. scRNA-seq analysis demonstrated that anlotinib reduced the proportions of myofibroblastic cancer-associated fibroblasts and ESM1+ endothelial cells, resulting in decreased angiogenesis. The combination of anlotinib and aPD-L1 further amplified these effects, promoting CD8+ T cell infiltration and reversing T cell exhaustion, whereas anlotinib + aPD-1 showed limited efficacy in this regard. Additionally, anlotinib + immunotherapy induced a shift toward M1 polarization of myeloid cells, enhanced anti-tumor activity, and inhibited immune escape. Cell-cell communication analysis revealed reduced APP-CD74 signaling and increased CD99-CD99 signaling, which might contribute to immune activation.

Conclusion

The combination of anlotinib and aPD-L1 effectively modulates the HGSOC tumor microenvironment by inhibiting angiogenesis, enhancing immune infiltration, and reversing T cell exhaustion.

Enhancing antitumor immunity: the role of immune checkpoint inhibitors, anti-angiogenic therapy, and macrophage reprogramming

Cancer treatment has long been hindered by the complexity of the tumor microenvironment (TME) and the mechanisms that tumors employ to evade immune detection. Recently, the combination of immune checkpoint inhibitors (ICIs) and anti-angiogenic therapies has emerged as a promising approach to improve cancer treatment outcomes. This review delves into the role of immunostimulatory molecules and ICIs in enhancing anti-tumor immunity, while also discussing the therapeutic potential of anti-angiogenic strategies in cancer. In particular, we highlight the critical role of endoplasmic reticulum (ER) stress in angiogenesis. Moreover, we explore the potential of macrophage reprogramming to bolster anti-tumor immunity, with a focus on restoring macrophage phagocytic function, modulating hypoxic tumor environments, and targeting cytokines and chemokines that shape immune responses. By examining the underlying mechanisms of combining ICIs with anti-angiogenic therapies, we also review recent clinical trials and discuss the potential of biomarkers to guide and predict treatment efficacy.

Lessons learned from a decade of immune checkpoint inhibition: The good, the bad, and the ugly

Discovering the brakes/checkpoints that cancer places on the immune system to prevent being eradicated led to the 2018 Nobel Prize and the development of multiple Food and Drug Administration-approved immune checkpoint inhibitors (ICIs). ICIs have transformed the treatment of numerous cancer types and, remarkably, some patients with end-stage metastatic disease can achieve durable, complete remissions - cures. Still, ICIs cause significant immune-related toxicities, and most tumors are resistant. Unusual progression patterns such as pseudo-progression and hyper-progression (accelerated progression) can occur. Biomarkers for ICI response/resistance include microsatellite instability, high tumor mutational burden, and PD-L1 immunohistochemistry positivity; but they are imperfect, perhaps because of immune system complexity. Herein, we explore the good, the bad, and the ugly of ICIs in cancer treatment.

Phototherapy in cancer treatment: strategies and challenges

Phototherapy has emerged as a promising modality in cancer treatment, garnering considerable attention for its minimal side effects, exceptional spatial selectivity, and optimal preservation of normal tissue function. This innovative approach primarily encompasses three distinct paradigms: Photodynamic Therapy (PDT), Photothermal Therapy (PTT), and Photoimmunotherapy (PIT). Each of these modalities exerts its antitumor effects through unique mechanisms-specifically, the generation of reactive oxygen species (ROS), heat, and immune responses, respectively. However, significant challenges impede the advancement and clinical application of phototherapy. These include inadequate ROS production rates, subpar photothermal conversion efficiency, difficulties in tumor targeting, and unfavorable physicochemical properties inherent to traditional phototherapeutic agents (PTs). Additionally, the hypoxic microenvironment typical of tumors complicates therapeutic efficacy due to limited agent penetration in deep-seated lesions. To address these limitations, ongoing research is fervently exploring innovative solutions. The unique advantages offered by nano-PTs and nanocarrier systems aim to enhance traditional approaches' effectiveness. Strategies such as generating oxygen in situ within tumors or inhibiting mitochondrial respiration while targeting the HIF-1α pathway may alleviate tumor hypoxia. Moreover, utilizing self-luminescent materials, near-infrared excitation sources, non-photoactivated sensitizers, and wireless light delivery systems can improve light penetration. Furthermore, integrating immunoadjuvants and modulating immunosuppressive cell populations while deploying immune checkpoint inhibitors holds promise for enhancing immunogenic cell death through PIT. This review seeks to elucidate the fundamental principles and biological implications of phototherapy while discussing dominant mechanisms and advanced strategies designed to overcome existing challenges-ultimately illuminating pathways for future research aimed at amplifying this intervention's therapeutic efficacy.

Unraveling Th subsets: insights into their role in immune checkpoint inhibitor therapy

T helper (Th) cell subsets play pivotal roles in regulating immune responses within the tumor microenvironment, influencing both tumor progression and anti-tumor immunity. Among these subsets, Th1 cells promote cytotoxic responses through the production of IFN-γ, while Th2 cells and regulatory T cells (Tregs) exert immunosuppressive effects that support tumor growth. Th9 and Th17 cells have context-dependent roles, contributing to both pro-inflammatory and regulatory processes in tumor immunity. Tumor antigen-specific T cells within the tumor microenvironment often exhibit a dysfunctional phenotype due to increased expression of inhibitory receptors such as CTLA-4 and PD-1, leading to reduced antitumor activity. Monoclonal antibodies that block these inhibitory signals-collectively known as immune checkpoint inhibitors (ICIs)-can reactivate these T cells, enhancing their ability to target and destroy cancer cells. Recent advancements have highlighted the critical role of T helper subsets in modulating responses to ICIs, with their interactions remaining a focus of ongoing research. Both positive and negative effects of ICIs have been reported in relation to Th cell subsets, with some effects depending on the type of tumor microenvironment. This review summarizes the crucial roles of different T helper cell subsets in tumor immunity and their complex relationship with immune checkpoint inhibitor therapy.

Regulatory T cell and endothelial cell crosstalk

Regulatory T (Treg) cells have a central role in the maintenance of immune surveillance and tolerance. They can migrate from lymphoid organs to blood and then into tissues and egress from tissues into draining lymph nodes. Specialized endothelial cells of blood and lymphatic vessels are the key gatekeepers for these processes. Treg cells that transmigrate across single-cell layers of endothelial cells engage in bidirectional crosstalk with these cells and regulate vascular permeability by promoting structural modifications of blood and lymphatic endothelial cells. In turn, blood and lymphatic endothelial cells can modulate Treg cell recirculation and residency. Here, we discuss recent insights into the cellular and molecular mechanisms of the crosstalk between Treg cells and endothelial cells and explore potential therapeutic strategies to target these interactions in autoimmunity, transplantation and cancer.

Paradoxical Effect of Myosteatosis on the Immune Checkpoint Inhibitor Response in Metastatic Renal Cell Carcinoma

BACKGROUND

Treatment for metastatic renal cell carcinoma (mRCC) has shifted from tyrosine kinase inhibitor (TKI) therapy to immune checkpoint inhibitor (ICI)-based therapy, improving outcomes but with variable individual responses. This study investigated the prognostic implications of pretreatment low skeletal muscle mass (LSMM) and myosteatosis in patients with mRCC undergoing first-line ICI-based therapies, comparing outcomes between PD-1 inhibitor + CTLA-4 inhibitor and PD-1 inhibitor + TKI, incorporating single-cell RNA sequencing.

METHODS

A retrospective analysis was performed on 90 patients with mRCC treated with ICI-based therapies between November 2019 and March 2023. Patients were grouped based on whether they received PD-1 inhibitor + CTLA-4 inhibitor or PD-1 inhibitor + TKI combinations. LSMM was defined as skeletal muscle index below 40.8 cm2/m2 for men and 34.9 cm2/m2 for women. Myosteatosis was defined using skeletal muscle density, with cut-off values < 41 HU for BMI < 25 kg/m2 and < 33 HU for BMI ≥ 25 kg/m2. Progression-free survival (PFS) and overall survival (OS) were compared using Kaplan-Meier curves and multivariable models. Single-cell RNA sequencing was performed on pretreatment samples to compare the immune microenvironment between patients with and without myosteatosis.

RESULTS

The study cohort (26.7% female; median age: 60.5 years) included 59 patients (65.6%) treated with PD-1 inhibitor + CTLA-4 inhibitor and 31 patients (34.4%) treated with PD-1 inhibitor + TKI. LSMM was present in 18.9% of patients, and myosteatosis in 41.1%, with comparable proportions across groups. During follow-up, 29 patients (32.2%) died: 16 in the PD-1 inhibitor + CTLA-4 inhibitor group and 13 in the PD-1 inhibitor + TKI group. The overall 1-year mortality rate was 22.2%, and PFS rate was 53.3%. Myosteatosis predicted poor OS (HR, 5.389; p = 0.008) and PFS (HR, 2.930; p = 0.022) in the PD-1 inhibitor + TKI group but was protective for PFS (HR, 0.461; p = 0.049) in the PD-1 inhibitor + CTLA-4 inhibitor group. LSMM did not significantly affect outcomes in either group. Single-cell RNA sequencing revealed higher CTLA-4 expression in regulatory T cells and more effector memory CD8+ T cells in patients with myosteatosis, whereas patients without myosteatosis had more anti-tumoural non-classical monocytes.

CONCLUSIONS

Myosteatosis negatively impacts OS and PFS in patients with mRCC treated with PD-1 inhibitor + TKI therapy but is protective for PFS in those treated with PD-1 inhibitor + CTLA-4 inhibitor therapy. Altered checkpoint expression and immune cell composition associated with myosteatosis may contribute to these differential responses.

Targeting TM4SF1 promotes tumor senescence enhancing CD8+ T cell cytotoxic function in hepatocellular carcinoma

BACKGROUND/AIMS

Transmembrane 4 L six family member 1 (TM4SF1) is highly expressed and contributes to the progression of various malignancies. However, how it modulates hepatocellular carcinoma (HCC) progression and senescence remains to be elucidated.

METHODS

TM4SF1 expression in HCC samples was evaluated using immunohistochemistry and flow cytometry. Cellular senescence was assessed through SA-β-gal activity assays and Western blot analysis. TM4SF1-related protein interactions were investigated using immunoprecipitation-mass spectrometry, co-immunoprecipitation, bimolecular fluorescence complementation, and immunofluorescence. Tumor-infiltrating immune cells were analyzed by flow cytometry. The HCC mouse model was established via hydrodynamic tail vein injection.

RESULTS

TM4SF1 was highly expressed in human HCC samples and murine models. Knockdown of TM4SF1 suppressed HCC proliferation both in vitro and in vivo, inducing non-secretory senescence through upregulation of p16 and p21. TM4SF1 enhanced the interaction between AKT1 and PDPK1, thereby promoting AKT phosphorylation, which subsequently downregulated p16 and p21. Meanwhile, TM4SF1-mediated AKT phosphorylation enhanced PD-L1 expression while reducing major histocompatibility complex class I level on tumor cells, leading to impaired cytotoxic function of CD8+ T cells and an increased proportion of exhausted CD8+ T cells. In clinical HCC samples, elevated TM4SF1 expression was associated with resistance to anti-PD-1 immunotherapy. Targeting TM4SF1 via adeno-associated virus induced tumor senescence, reduced tumor burden and synergistically enhanced the efficacy of anti-PD-1 therapy.

CONCLUSION

Our results revealed that TM4SF1 regulated tumor cell senescence and immune evasion through the AKT pathway, highlighting its potential as a therapeutic target in HCC, particularly in combination with first-line immunotherapy.

Targeting lipid metabolism in regulatory T cells for enhancing cancer immunotherapy

As immunosuppressive cells, Regulatory T cells (Tregs) exert their influence on tumor immune escape within the tumor microenvironment (TME) by effectively suppressing the activity of other immune cells, thereby significantly impeding the anti-tumor immune response. In recent years, the metabolic characteristics of Tregs have become a focus of research, especially the important role of lipid metabolism in maintaining the function of Tregs. Consequently, targeted interventions aimed at modulating lipid metabolism in Tregs have been recognized as an innovative and promising approach to enhance the effectiveness of tumor immunotherapy. This review presents a comprehensive overview of the pivotal role of lipid metabolism in regulating the function of Tregs, with a specific focus on targeting Tregs lipid metabolism as an innovative approach to augment anti-tumor immune responses. Furthermore, we discuss potential opportunities and challenges associated with this strategy, aiming to provide novel insights for enhancing the efficacy of cancer immunotherapy.

α1,3 Fucosyltransferase VII Improves Intestinal Immune Homeostasis in Inflammatory Bowel Disease by Enhancing Regulatory T-Cell Intestinal Homing and Immunosuppression

BACKGROUND & AIMS

Regulatory T cells (Tregs) play a critical role in maintaining tissue immune homeostasis, but they are relatively insufficient at inflammatory intestinal sites in patients with inflammatory bowel disease (IBD). However, what controls Treg homing to the intestine in IBD is unknown.

METHODS

α1,3 Fucosyltransferase VII (FUT7) expression in Tregs from patients with active IBD was detected by RNA sequencing. To determine whether FUT7 controls Treg intestinal homing in IBD, Treg-specific Fut7 conditional knockout (CKO) mice were constructed and used in an IBD model induced by dextran sulfate sodium. To investigate whether up-regulating FUT7 expression in Tregs plays a therapeutic role in IBD, the nanocarrier CD4-LDP-Fut7, which specifically targets Tregs to express Fut7, was constructed and used in the IBD model. In addition, whether Fut7 regulates other Treg functions was explored by mass cytometry.

RESULTS

Compared with healthy controls, patients with active IBD had significantly decreased FUT7 expression in Tregs. In the IBD model, CKO mice had a lower frequency of colonic Tregs among CD4+ T cells and a lower ratio of colonic to splenic Tregs from the same mouse than their littermate controls did, indicating that Fut7 deficiency impaired the ability of Tregs to home to the intestine. Consistently, CKO mice had severe colitis, and CD4-LDP-Fut7 alleviated it in the IBD model. Mass cytometry analysis revealed that Fut7 down-regulated PD1 expression in Tregs via competition with Fut8 for the substrate GDP-fucose, thereby increasing the immunosuppressive capacity of Tregs.

CONCLUSIONS

FUT7 enhances Treg intestinal homing and immunosuppression. Thus, up-regulating FUT7 expression in Tregs could be a novel therapeutic strategy for IBD.

Immunogenomic cancer evolution: A framework to understand cancer immunosuppression

The process of tumor development involves tumor cells eluding detection and suppression of immune responses, which can cause decreased tumor cell antigenicity, expression of immunosuppressive molecules, and immunosuppressive cell recruitment to the tumor microenvironment (TME). Immunologically and genomically integrated analysis (immunogenomic analysis) of patient specimens has revealed that oncogenic aberrant signaling is involved in both carcinogenesis and immune evasion. In noninflamed cancers such as epidermal growth factor receptor (EGFR)-mutated lung cancers, genetic abnormalities in cancer cells contribute to the formation of an immunosuppressive TME by recruiting immunosuppressive cells, which cannot be fully explained by the cancer immunoediting hypothesis. This review summarizes the latest findings regarding the links between cancer genetic abnormalities and immunosuppression causing clinical resistance to immunotherapy. We propose the concepts of immunogenomic cancer evolution, in which cancer cell genomic evolution shapes the immunosuppressive TME, and immunogenomic precision medicine, in which cancer immunotherapy can be combined with molecularly targeted reagents that modulate the immunosuppressive TME.

Poor prognosis in IBD-complicated colon cancer through gut dysbiosis-related immune response failure

Background

Colorectal cancer (CRC) results from the accumulation of mutations and epigenetic changes in gut epithelial cells likely due to gut microbiota dysbiosis. However, limited research has been done to explore the link between host tumour dysbiosis and disease outcome.

Methods

The mechanisms influencing outcomes of 97 colorectal cancer (CRC) patients, including 13 with Lynch syndrome, 20 with inflammatory bowel disease (IBD), and 64 sporadic cases, were analyzed using a multiomics approach. These patients were categorized into two groups: "disease-free/stable disease" and "progression disease" survival outcomes. The analysis included tumor adherent microbiota composition (16S rRNA), somatic gene mutations (WES), gene expression (RNAseq), immune markers (RNAscope), and immune infiltrate cells (immunohistochemistry).

Results

IBD-CRC patients had worse outcomes than those with Lynch or sporadic CRC, regardless of TNM staging or treatment. Symbiotic bacteria like Lactococcus lactis were significantly reduced in IBD-CRC tissues. Patient outcomes were influenced by the abundance of virulent ( Escherichia coli ) relative to beneficial bacteria ( Lactococcus lactis ). Although no significant increase in deleterious somatic mutations was found in IBD-CRC. 16sRNA revealed increased virulent- and decreased anti-inflammatory symbiotic-bacteria correlating with the upregulation of oncogenes and downregulation of anti-oncogenes like PHLPP1. The multiplex in situ hybridization of CD8, IFNγ and PHLPP1 an anti-oncogene revealed significant decrease of immune cells with detectable PHLPP1 expression in IBD-CRC tumour tissues as compared to sporadic CRCs.

Conclusion

The poor outcomes in IBD-CRC patients are likely due to gut dysbiosis and immune cell alterations, possibly triggered by microbiota-related epigenetic pathways.

What You Need to Know

BACKGROUND AND CONTEXT: Colorectal cancer (CRC) is associated with gut microbiota dysbiosis. Inflammatory bowel disease-related CRC (IBD-CRC) is classified as an environment-related condition.NEW FINDINGS: In relation with patient outcomes, tumour tissues from three types of CRC (Sporadic-, IBD-, and Lynch syndrome-CRC) were analyzed using a multiomic approach. This included examining tissue adherent virulent bacteria, gene analyses, and quantifying immune cell infiltration in the mucosa. IBD-CRC patients had the worst outcomes, associated with the down regulation of PHLPP1 gene, virulent/symbiotic imbalance, and immune response failure.LIMITATIONS: Lack of animal experiments using FMT of fresh stool from IBD-CRC patients.CLINICAL AND TRANSLATIONAL RESEARCH RELEVANCE: Among the different types of CRC, IBD-CRC patients showed a greater imbalance between harmful and beneficial bacteria, along with immune response failure.Lay summary: This study compares the pathological and clinical characteristics of patients with colorectal cancer (CRC) across three distinct etiologies: sporadic CRC, inflammatory bowel disease (IBD)-associated CRC, and Lynch syndrome-associated CRC (LS-CRC). Distinct differences in tumor-adherent microbiota, gene expression and immune response profiles were observed. Notably, IBD-CRC patients demonstrated the poorest prognosis depending on microbe-host gene interaction highlighting potential biomarkers for disease prognosis and treatment strategies.

CD38-mediated metabolic reprogramming promotes the stability and suppressive function of regulatory T cells in tumor

In the tumor microenvironment (TME), regulatory T cells (Tregs) adapt their metabolism to thrive in low-glucose, high-lactate conditions, but the mechanisms remain unclear. Our study identifies CD38 as a key regulator of this adaptation by depleting nicotinamide adenine dinucleotide (oxidized form) (NAD+), redirecting lactate-derived pyruvate toward phosphoenolpyruvate and bypassing the tricarboxylic acid (TCA) cycle. This prevents accumulation of α-ketoglutarate, which destabilizes Tregs by inducing hypermethylation at the Foxp3 locus. Restoring NAD+ with nicotinamide mononucleotide reverses this adaptation, pushing Tregs back to the TCA cycle and reducing their suppressive function. In YUMM1.7 melanoma-bearing mice, small-molecule CD38 inhibition selectively destabilizes intratumoral Tregs, sparking robust antitumor immunity. These findings reveal that targeting the CD38-NAD+ axis disrupts Tregs metabolic adaptation and offers a strategy to enhance antitumor responses.

Genetically engineered macrophages reverse the immunosuppressive tumor microenvironment and improve immunotherapeutic efficacy in TNBC

The main challenges in current immunotherapy for triple-negative breast cancer (TNBC) lie in the immunosuppressive tumor microenvironment (TME). Considering tumor-associated macrophages (TAMs) are the most abundant immune cells in the TME, resetting TAMs is a promising strategy for ameliorating the immunosuppressive TME. Here, we developed genetically engineered macrophages (GEMs) with gene-carrying adenoviruses, to maintain the M1-like phenotype and directly deliver the immune regulators interleukin-12 and CXCL9 into local tumors, thereby reversing the immunosuppressive TME. In tumor-bearing mice, GEMs demonstrated targeted enrichment in tumors and successfully reprogramed TAMs to M1-like macrophages. Moreover, GEMs significantly enhanced the accumulation, proliferation, and activation of CD8+ T cells, mature dendritic cells, and natural killer cells within tumors, while diminishing M2-like macrophages, immunosuppressive myeloid-derived suppressor cells, and regulatory T cells. This treatment efficiently suppressed tumor growth. In addition, combination therapy with GEMs and anti-programmed cell death protein 1 further improved interferon-γ+CD8+ T cell percentages and tumor inhibition efficacy in an orthotopic murine TNBC model. Therefore, this study provides a novel strategy for reversing the immunosuppressive TME and improving immunotherapeutic efficacy through live macrophage-mediated gene delivery.

Exosomal PD-L1 and lactate versus tissue PD-L1 as biomarkers for clinical outcomes of PD-1 Blockade plus chemotherapy in metastatic esophagogastric signet ring cell carcinoma

In this investigator-initiated, prospective, exploratory study, biomarkers predictive of clinical outcomes of first-line immune checkpoint inhibitor (ICI, nivolumab or pembrolizumab) plus XELOX(oxaliplatin and capecitabine) were identified in human epidermal growth factor receptor 2 (HER2)-negative patients with metastatic esophagogastric signet ring cell carcinoma. The findings showed an objective response rate (ORR) of 51.5% and a disease control rate of 86.8%, the median progression-free survival (PFS) for the entire cohort was 6.63 months. PD-L1 expression level in tumor tissues could not identify a high PD-L1 group that significantly benefited from ICI plus XELOX in terms of the ORR and PFS. By contrast, the patients expressing low exosomal PD-L1 or lactate in peripheral blood plasma before treatment initiation demonstrated a significantly increased ORR and prolonged PFS compared to that with high exosomal PD-L1 or lactate, patients with combining predictor of exosomal PD-L1 and lactate lower than - 0.249 was associated with a better ORR (82.1% vs. 30.0%, P < 0.001) and a longer median PFS (13.83 vs. 5.50 months, P < 0.001) compared to those with combining predictor ≥-0.249. The results also revealed that exosomal PD-L1 levels in peripheral blood plasma before the treatment were significantly correlated with the frequency of CD8+ T cells (P = 0.007), and in patients after receiving ICI plus XELOX, high exosomal PD-L1 level was associated with more PD-1+ Treg cells, high exosomal lactate level was associated with less CD8+ T cells and more Treg cells. Thus, the levels of PD-L1 and lactate in exosomes may affect the balance between Treg cells and CD8+T cells, leading to treatment resistance to ICI plus XELOX. Compared to PD-L1 expression level in tumor tissues, exosomal PD-L1 and lactate levels could more accurately predict clinical outcomes of HER2-negative patients with metastatic esophagogastric signet ring cell carcinoma receiving first-line PD-1 blockade plus chemotherapy.

Identification of the Molecular Subtype and Prognostic Characteristics of Breast Cancer Based on Tumor-Infiltrating Regulatory T Cells

Background: T regulatory cells (Tregs) are essential for preserving immune tolerance. They are present in large numbers in many tumors, hindering potentially beneficial antitumor responses. However, their predictive significance for breast cancer (BC) remains ambiguous. This study aimed to explore genes associated with Tregs and develop a prognostic signature associated with Tregs. Methods: The gene expression and clinical data on BC were obtained from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. The integration of CIBERSORT and weighted correlation network analysis (WGCNA) algorithms was utilized to identify modules associated with Tregs. The consensus cluster algorithm was utilized to create molecular subtypes determined by genes associated with Tregs. Then, a prognostic signature associated with Tregs was constructed and its relationship to tumor immunity and the prognosis was evaluated. Results: The blue module genes exhibited the most significant correlation with Tregs, and 1080 genes related to Tregs were acquired. A total of 93 genes from the TCGA dataset were found to have a significant impact on patient prognosis. Samples from BC were categorized into two clusters by consensus cluster analysis. The overall survival, immune checkpoint genes, molecular subtype, and biological behaviors varied significantly between these two subtypes. A 10-gene signature developed from differentially expressed genes between two subtypes demonstrated consistent prognostic accuracy in both TCGA and GEO datasets. It functioned as a standalone prognostic marker for individuals with BC. In addition, patients with low risk are more inclined to exhibit increased immune cell infiltration, TME score, and tumor mutation burden (TMB). Meanwhile, Individuals classified within the low-risk group showed better responses to immunotherapies compared to their counterparts in the high-risk group. Conclusions: The prognostic model derived from Tregs-related genes could aid in assessing the prognosis, guiding personalized treatment, and potentially enhancing the clinical outcomes for patients with BC.

Exploring radiation resistance-related genes in pancreatic cancer and their impact on patient prognosis and treatment

Background

Pancreatic cancer is a highly lethal disease with increasing incidence worldwide. Despite surgical resection being the main curative option, only a small percentage of patients are eligible for surgery. Radiotherapy, often combined with chemotherapy, remains a critical treatment, especially for locally advanced cases. However, pancreatic cancer's aggressiveness and partial radio resistance lead to frequent local recurrence. Understanding the mechanisms of radiotherapy resistance is crucial to improving patient outcomes.

Methods

Pancreatic cancer related gene microarray data were downloaded from GEO database to analyze differentially expressed genes before and after radiotherapy using GEO2R online tool. The obtained differentially expressed genes were enriched by GO and KEGG to reveal their biological functions. Key genes were screened by univariate and multivariate Cox regression analysis, and a risk scoring model was constructed, and patients were divided into high-risk group and low-risk group. Subsequently, Kaplan-Meier survival analysis was used to compare the survival differences between the two groups of patients, further analyze the differential genes of the two groups of patients, and evaluate their sensitivity to different drugs.

Results

Our model identified 10 genes associated with overall survival (OS) in pancreatic cancer. Based on risk scores, patients were categorized into high- and low-risk groups, with significantly different survival outcomes and immune profile characteristics. High-risk patients showed increased expression of pro-inflammatory immune markers and increased sensitivity to specific chemotherapy agents, while low-risk patients had higher expression of immune checkpoints (CD274 and CTLA4), indicating potential sensitivity to targeted immunotherapies. Cross-dataset validation yielded consistent AUC values above 0.77, confirming model stability and predictive accuracy.

Conclusion

This study provides a scoring model to predict radiotherapy resistance and prognosis in pancreatic cancer, with potential clinical application for patient stratification. The identified immune profiles and drug sensitivity variations between risk groups highlight opportunities for personalized treatment strategies, contributing to improved management and survival outcomes in pancreatic cancer.

Endothelial OX40 activation facilitates tumor cell escape from T cell surveillance through S1P/YAP-mediated angiogenesis

Understanding the complexity of the tumor microenvironment is vital for improving immunotherapy outcomes. Here, we report that the T cell costimulatory molecule OX40 was highly expressed in tumor endothelial cells (ECs) and was negatively associated with the prognosis of patients, which is irrelevant to T cell activation. Analysis of conditional OX40 loss- and gain-of-function transgenic mice showed that OX40 signal in ECs counteracted the antitumor effects produced in T cells by promoting angiogenesis. Mechanistically, leucine-rich repeat-containing GPCR5 (Lgr5+ ) cancer stem cells induced OX40 expression in tumor ECs via EGF/STAT3 signaling. Activated OX40 interacted with Spns lysolipid transporter 2 (Spns2), obstructing the export of sphingosine 1-phosphate (S1P) and resulting in S1P intracellular accumulation. Increased S1P directly bound to Yes 1-associated protein (YAP), disrupting its interaction with large tumor suppressor kinase 1 (LATS1) and promoting YAP nuclear translocation. Finally, the YAP inhibitor verteporfin enhanced the antitumor effects of the OX40 agonist. Together, these findings reveal an unexpected protumor role of OX40 in ECs, highlighting the effect of nonimmune cell compartments on immunotherapy.

N6-methyladenosine modification of 3'tRF-AlaAGC impairs PD-1 blockade efficacy by promoting lactic acid accumulation in the tumor microenvironment of gastric carcinoma

The balance between CD8+ T cells and regulatory T (Treg) cells in the tumor microenvironment (TME) plays a crucial role in the immune checkpoint inhibition (ICI) therapy in gastric carcinoma (GC). However, related factors leading to the disturbance of TME and resistance to ICI therapy remain unknown. In this study, we applied N6-methyladenosine (m6A) small RNA Epitranscriptomic Microarray and screened out 3'tRF-AlaAGC based on its highest differential expression level and lowest inter-group variance. N6-methyladenosine modification significantly enhanced the stability of 3'tRF-AlaAGC, which strengthened glycolysis and lactic acid (LA) production in GC cells by binding to PTBP1 (Polypyrimidine Tract Binding Protein 1). In the peritoneal GC implantation model established in huPBMC-NCG mice, 3'tRF-AlaAGC significantly increased the proportion of PD1+ Treg cells. Furthermore, in high-LA environments driven by glucose consumption of GC cells, Treg cells actively uptake LA through MCT1, facilitating NFAT1 translocation into the nucleus and enhancing PD1 expression, whereas PD1 expression by effector T cell is diminished. Meanwhile, T cell suppression assays were performed under low-LA or high-LA conditions, and the proliferation of CD8+ T cells was dampened by adding Sintilimab in a high-LA but not in a low-LA environment, suggesting the preferential activation of PD1+ Treg cell. These findings deciphered the complexities of the immune microenvironment in GC, providing prospects for identifying robust biomarkers that could improve the evaluation of therapeutic effectiveness and prognosis in immune therapy for GC.

Harnessing phytochemicals: Innovative strategies to enhance cancer immunotherapy

Cancer immunotherapy has revolutionized cancer treatment, but therapeutic ineffectiveness-driven by the tumor microenvironment and immune evasion mechanisms-continues to limit its clinical efficacy. This challenge underscores the need to explore innovative approaches, such as multimodal immunotherapy. Phytochemicals, bioactive compounds derived from plants, have emerged as promising candidates for overcoming these barriers due to their immunomodulatory and antitumor properties. This review explores the synergistic potential of phytochemicals in enhancing immunotherapy by modulating immune responses, reprogramming the tumor microenvironment, and reducing immunosuppressive factors. Integrating phytochemicals with conventional immunotherapy strategies represents a novel approach to mitigating resistance and enhancing therapeutic outcomes. For instance, nab-paclitaxel has shown the potential in overcoming resistance to immune checkpoint inhibitors, while QS-21 synergistically enhances the efficacy of tumor vaccines. Furthermore, we highlight recent advancements in leveraging nanotechnology to engineer phytochemicals for improved bioavailability and targeted delivery. These innovations hold great promise for optimizing the clinical application of phytochemicals. However, further large-scale clinical studies are crucial to fully integrate these compounds into immunotherapeutic regimens effectively.

Safety and Antitumor Activity of a Novel aCD25 Treg Depleter RG6292 as a Single Agent and in Combination with Atezolizumab in Patients with Solid Tumors

PURPOSE

Therapeutic depletion of immunosuppressive regulatory T cells (Treg) may overcome resistance to cancer immunotherapies. RG6292 is an anti-CD25 antibody that preferentially depletes Tregs while preserving effector T-cell functions in preclinical models. The safety, pharmacokinetics, pharmacodynamics, and antitumor efficacy of selective Treg depletion by RG6292 administered as monotherapy or in combination with atezolizumab were evaluated in two phase I studies.

PATIENTS AND METHODS

Adult patients with advanced solid tumors were administered intravenous RG6292, given every 3 weeks alone (study 1: NCT04158583, n = 76) or with 1,200 mg atezolizumab every 3 weeks (study 2: NCT04642365, n = 49). Both studies included dose escalation and expansion parts to determine the maximum tolerated dose and recommended phase II dose.

RESULTS

RG6292 was well tolerated. Pruritus and rash were the most frequent adverse events and were manageable with supportive treatment. Serum RG6292 levels increased dose proportionally, independent of the atezolizumab combination. RG6292 induced a sustained dose-dependent depletion of peripheral Tregs with no apparent effect on other immune cells. Evidence of intratumoral Treg reduction (≥50% vs. baseline) was observed at RG6292 doses of 35 to 100 mg. The maximum tolerated dose was 165 mg every 3 weeks, and the recommended phase II dose was proposed as 70 mg every 3 weeks. Objective responses were limited to three partial responses in patients receiving RG6292 combined with atezolizumab.

CONCLUSIONS

RG6292 induced a dose-dependent peripheral blood and measurable intratumoral Treg depletion in concordance with the proposed mode of action; however, clinical efficacy as a single agent or combined with atezolizumab was insufficient to warrant further exploration in this population.

SIGNIFICANCE

RG6292 (vopikitug) targets CD25 (IL-2Rα) and mediates regulatory T-cell depletion while not interfering with IL-2 signaling. Peripheral and intratumoral Treg depletion was shown in two phase I studies. However, RG6292 alone or in combination with atezolizumab was insufficient to reverse and rescue from established resistance mechanisms in solid tumors.

Atezolizumab following definitive chemoradiotherapy in patients with unresectable locally advanced esophageal squamous cell carcinoma - a multicenter phase 2 trial (EPOC1802)

Platinum-based definitive chemoradiotherapy (dCRT) is the standard treatment for patients with unresectable locally advanced esophageal squamous cell carcinoma (ESCC) that invades the aorta, vertebral body or trachea; however, complete response rates remain low (11-25%), leading to poor survival. To evaluate the additive efficacy of the anti-PD-L1 antibody drug atezolizumab, we conducted a phase 2, multicenter, single-arm trial of 1 year of atezolizumab treatment following dCRT in 40 patients with unresectable locally advanced ESCC recruited from seven Japanese centers (UMIN000034373). The confirmed complete response (cCR) rate (primary end point) of the first consecutive 38 patients was 42.1% (90% CI 28.5-56.7%). Regarding the secondary end points, the median progression-free survival and 12-month progression-free survival rates of all 40 patients were 3.2 months and 29.6%, respectively, and the preliminary median overall survival with short-term follow-up and 12-month overall survival rate were 31.0 months and 65.8%, respectively. Other secondary end points evaluated included the cCR rate determined by an investigator's assessment in the locoregionally recurrent ESCC cohort, cCR rate determined by central assessment, overall response rate and incidence of adverse events. No treatment-related death occurred during the study. Atezolizumab monotherapy after dCRT resulted in a promising cCR rate, although long-term survival data are required.

Opposing Functions of Distinct Regulatory T Cell Subsets in Colorectal Cancer

Regulatory T (Treg) cells contribute to solid organ cancer progression, except in colorectal cancer (CRC) despite being abundantly present. Here, we demonstrate that two distinct tumoral IL-10⁺ and IL-10⁻ Treg cell subsets exert opposing functions by counteracting and promoting CRC tumor growth, respectively. The tumor restraining activity of IL-10⁺ Treg cells was mediated by their suppression of effector CD4 T cell production of IL-17, which directly stimulates CRC tumor cell proliferation. Consistently, IL-10⁻ Treg cells were more abundant in both mouse and human CRC tumors than in tumor-adjacent normal tissues, whereas IL-10+ Treg cells exhibited the opposite distribution. Furthermore, relative abundance of IL-10⁺ and IL-10⁻ Treg cells correlated with better and worse disease prognoses in human CRC, respectively. This functional dichotomy between Treg cell subsets provides a rationale for therapeutic strategies to selectively target pro-tumoral Treg cells while preserving their anti-tumoral counterparts across barrier tissue cancers that harbor both subsets.

Regulatory T cells in the tumor microenvironment display a unique chromatin accessibility profile

Regulatory T cells (Tregs) are a suppressive CD4+ T cell population that limit the antitumor immune response. In this study, we analyzed the chromatin accessibility of Tregs in the murine tumor microenvironment (TME) to identify tumor-specific accessible peaks and if these are altered over time in the tumor microenvironment, with or without anti-PD-1 immunotherapy. We found that despite little change in chromatin accessibility of Tregs in the tumor over time, Tregs have a distinct chromatin accessibility signature in the TME compared with Tregs in the periphery. This distinct tumor Treg chromatin accessibility profile highlights reduced accessibility at loci important for an CD4+ conventional T cell (CD4+ Foxp3-) effector phenotype. Analysis of chromatin accessibility in Tregs from B16 and MC38 tumor models indicated that Tregs from skin-resident tumors are most similar to naïve skin resident Tregs but still bear key differences attributable to the TME. We also found that Tregs do not alter their transcriptome or chromatin accessibility following immunotherapy. We conclude that although chromatin accessibility in Tregs is somewhat similar to their tissue residency, the TME may drive a unique chromatin accessibility profile. Treg chromatin accessibility in the tumor appears remarkably stable and unaltered by tumor type, over time, or following immunotherapy.

Adenosine Uptake through the Nucleoside Transporter ENT1 Suppresses Antitumor Immunity and T-cell Pyrimidine Synthesis

Immunosuppression by adenosine is an important cancer immune checkpoint. Extracellular adenosine signals through specific receptors and can be transported across the cell membrane through nucleoside transporters. Although adenosine receptors are well-known to regulate tumor immunity, the impact of adenosine transporters remains unexplored. In this study, we investigated the effect on tumor immunity of equilibrative nucleoside transporter-1 (ENT1), the major regulator of extracellular adenosine concentrations. Blocking or deleting host ENT1 significantly enhanced CD8+ T-cell-dependent antitumor responses. Tumors inoculated into ENT1-deficient mice showed increased infiltration of effector CD8+ T cells with an enhanced cytotoxic transcriptomic profile and significant upregulation of granzyme B, IFNγ, IL2, TNFα, and CXCL10. ENT1 deficiency was further associated with decreased tumor-infiltrating T regulatory cells and CD206high macrophages and suppressed CCL17 production. ENT1 deficiency notably potentiated the therapeutic activity of PD-1 blockade. T cells upregulated ENT1 upon activation, and blocking ENT1 enhanced their function when cocultured with cognate antigen/HLA-matched melanoma cells. Mechanistically, ENT1-mediated adenosine uptake inhibited the activity of phosphoribosyl pyrophosphate synthetase in activated T cells, thereby suppressing production of uridine 5'-monophosphate and its derivatives required for DNA and RNA synthesis. In summary, this study identified ENT1-mediated adenosine uptake as an important mechanism of adenosine-mediated immunosuppression and pyrimidine starvation that can be targeted to enhance antitumor T-cell responses. Significance: ENT1 is a potential therapeutic target to overcome immunosuppression induced by extracellular adenosine and to increase the activity of PD-1 blockade.

PD1+ Treg cell remodeling promotes immune homeostasis within peripheral blood and tumor microenvironment after microparticles-transarterial chemoembolization in hepatocellular carcinoma

The effects of transarterial chemoembolization (TACE) on the systemic immune in hepatocellular carcinoma (HCC) are not well understood. We aimed to reveal the temporal and spatial changes in the immune profile of peripheral blood and tumor tissues in HCC patients following TACE. Eighty-four HCC patients were included, 20 of whom received TACE with a median follow-up of 28 months. Immune cell proportion within peripheral blood was profiled with flow cytometry, and therapeutic efficacy was evaluated by imaging examinations. Additionally, cell distribution within tumor microenvironment (TME) were compared between the necrotic tumor infiltration zone (N-IZ) and the residual tumor infiltration zone (R-IZ) by multiplex immunofluorescence. Among 20 patients, 25% (5/20) achieved complete response, and 75% (15/20) showed partial response. Fourteen patients received combinational targeted therapy and immunotherapy and the median progression-free survival was 15.5 months. Compared to healthy individuals, HCC exhibited significantly higher proportions of regulatory T cells (Tregs) and programmed death-1 receptor (PD1)+ Tregs within peripheral blood. PD1+ Treg cells, PD1+ CD4+ T cells and PD1+ CD8+ T cells decreased significantly within peripheral blood after TACE. In TME, N-IZ showed significantly lower CD4+ T, CD8+ T and FOXP3+ Tregs, higher PD1+ CD8+/CD8+ and PD1+ CD8+/ PD1+ FOXP3+. Moreover, the spatial distance between CD8+ T cells and the nearest FOXP3+ Tregs in N-IZ was significantly greater than in R-IZ. Our findings demonstrated that TACE could both remodel the immune components in peripheral blood and TME, strengthening the rationale for developing immunotherapy alongside TACE.

Coactivation of innate immune suppressive cells induces acquired resistance against combined TLR agonism and PD-1 blockade

Immune checkpoint blockade therapy has been successfully applied in clinical settings as a standard therapy for many cancer types, but its clinical efficacy is restricted to patients with immunologically hot tumors. Various strategies to modify the tumor microenvironment (TME), such as Toll-like receptor (TLR) agonists that can stimulate innate immunity, have been explored but have not been successful. Here, we show a mechanism of acquired resistance to combination treatment consisting of an agonist for multiple TLRs, OK-432 (Picibanil), and programmed cell death protein 1 (PD-1) blockade. Adding the TLR agonist failed to convert the TME from immunogenically cold to hot and did not augment antitumor immunity, particularly CD8+ T cell responses, in multiple animal models. The failure was attributed to the coactivation of innate suppressive cells, such as polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) expressing CXCR2, through high CXCL1 production by macrophages in the TME upon OK-432 treatment. A triple combination treatment with OK-432, PD-1 blockade, and a CXCR2 neutralizing antibody overcame the resistance induced by PMN-MDSCs, resulting in a stronger antitumor effect than that of any dual combinations or single treatments. The accumulation of PMN-MDSCs was similarly observed in the pleural effusions of patients with lung cancer after OK-432 administration. We propose that successful combination cancer immunotherapy intended to stimulate innate antitumor immunity requires modulation of unwanted activation of innate immune suppressive cells, including PMN-MDSCs.

Contrasting cytotoxic and regulatory T cell responses underlying distinct clinical outcomes to anti-PD-1 plus lenvatinib therapy in cancer

Combination of anti-PD-1 with lenvatinib showed clinical efficacy in multiple cancers, yet the underlying immunological mechanisms are unclear. Here, we compared T cells in hepatocellular carcinoma (HCC) patients before and after combination treatment using single-cell transcriptomics and T cell receptor (scTCR) clonotype analyses. We found that tumor-infiltrating GZMK+ CD8+ effector/effector memory T (Teff/Tem) cells, showing a favorable response to combination therapy, comprise progenitor exhausted T (Tpex) cells and also unappreciated circulating Tem (cTem) cells enriched with hepatitis B virus (HBV) specificity. Further integrated analyses revealed that cTem cells are specifically associated with responsiveness to the combination therapy, whereas Tpex cells contribute to responses in both combination therapy and anti-PD-1 monotherapy. Notably, an underexplored KIR+ CD8+ T cell subset in the tumor and FOXP3+ CD4+ regulatory T cells are specifically enriched in non-responders after the combination therapy. Our study thus elucidated T cell subsets associated with clinical benefits and resistance in cancer immunotherapy.

Predominance of hyperprogression in mucosal melanoma during anti-PD-1 monotherapy treatment

BACKGROUND

A minority subset of immunotherapy patients manifests hyperprogressive disease (HPD), with the disparity in melanoma subtypes yet to be reported. This study aimed to delineate the proportion and prognosis of HPD in patients receiving anti-PD-1 monotherapy and to identify patient with HPD clinical characteristics across melanoma subtypes to inform clinical decision making.

METHODS

Utilizing 4 established HPD definitions, the incidence of HPD in patients with advanced melanoma on anti-PD-1 monotherapy was determined. The incidence rates and prognostic abilities of various HPD definitions were compared to elect the most effective one. This facilitated a comparative analysis of subtypes and clinical features between patients with HPD and traditional progression.

RESULTS

A total of 262 patients with advanced melanoma treated with anti-PD-1 monotherapy from 5 prospectively registered clinical trials were included in the study. The objective response rate (ORR) and disease control rate (DCR) was 21% and 58%, respectively, with 42% showcasing progression disease. The HPD incidences by 4 definitions were 13.2%, 16.8%, 10.8%, and 28.2%. All definitions effectively segregated HPD patients, with significantly poorer outcome than other progressive patients. The Delta TGR > 100 definition was the most indicative of a reduced overall survival, corroborated by the highest hazard ratio and statistical significance. The number of metastatic organs over 2 is a risk factor for HPD (OR = 4.18, P = .0103). Mucosal melanoma was the HPD prevalent subtype (OR = 3.13, P = .0489) in multivariable analysis, which is also indicated by RECIST criteria (P = .005).

CONCLUSION

A delta TGR exceeding 100 best identified HPD patients in the advanced melanoma population treated with anti-PD-1 monotherapy. Hyperprogression was notably prevalent in mucosal melanoma patients with multiple metastatic organs. Caution against HPD is warranted when applying anti-PD-1 monotherapy in mucosal subtype.

Unleashing the Power of immune Checkpoints: A new strategy for enhancing Treg cells depletion to boost antitumor immunity

Regulatory T (Treg) cells, immunosuppressive CD4+ T cells, can impede anti-tumor immunity, complicating cancer treatment. Since their discovery, numerous studies have been dedicated to understand Treg cell biology, with a focus on checkpoint pathways' role in their generation and function. Immune checkpoints, such as PD-1/PD-L1, CTLA-4, TIGIT, TIM-3, and OX40, are pivotal in controlling Treg cell expansion and activity in the tumor microenvironment (TME), affecting their ability to suppress immune responses. This review examines the complex relationship between these checkpoints and Tregs in the TME, and how they influence tumor immunity. We also discuss the therapeutic potential of targeting these checkpoints to enhance anti-tumor immunity, including the use of immune checkpoint blockade (ICB) therapies and novel approaches such as CCR8-targeted therapies. Understanding the interaction between immune checkpoints and Treg cells can lead to more effective immunotherapeutic strategies, such as combining CCR8-targeted therapies with immune checkpoint inhibitors, to improve patient outcomes in cancer treatment.

The HSP90 Inhibitor Pimitespib Targets Regulatory T Cells in the Tumor Microenvironment

Regulatory T (Treg) cells play key roles in cancer immunity by suppressing a range of antitumor immune responses and contributing to resistance to PD-1 blockade therapy. Given their critical roles in self-tolerance, local control of immunosuppression by Treg cells, such as in the tumor microenvironment, has been intensively studied. Inhibition of HSP90, a chaperone with vital roles in regulating proteostasis in cancer cells, impedes cancer progression by interrupting oncogenic signaling pathways and potentially modulating antitumor immunity, but we have very little mechanistic insight into these immune modulatory effects. In this study, we show that the number of Treg cells is selectively reduced by the HSP90 inhibitor pimitespib in animal models and patients with gastric cancer in a clinical trial (EPOC1704). Pimitespib reduced the highly immunosuppressive human FOXP3high effector Treg cells by inhibiting their proliferation and decreasing their expression of effector molecules, which improved the priming and activation of antigen-specific CD8+ T cells. Mechanistic studies revealed that pimitespib selectively degraded STAT5, a key transducer of the IL2 signaling pathway, which is essential for Treg cell development and maintenance, and consequently compromised FOXP3 expression, leading to selective impairment of immunosuppression in the tumor microenvironment by Treg cells. Thus, pimitespib treatment combined with PD-1 blockade exhibited a far stronger antitumor effect than either treatment alone in animal models. Through these data, we propose that HSP90 inhibition is a promising therapeutic option for Treg cell-targeted cancer immunotherapy.

Phospholipase D2 downregulates interleukin-1β secretion from tumor-associated macrophages to suppress bladder cancer progression

The tumor microenvironment (TME) modulates therapeutic response and prognosis in patients with bladder cancer (BC). The roles of two phospholipase D (PLD) isoforms, PLD1 and PLD2 (hydrolysis of phosphatidylcholine to phosphatidic acid), in cancer cells have been well-studied in numerous cancer types, but their roles in the TME remain unclear. We used a mouse BC Pld2-KO carcinogenesis model and global transcriptomic analysis to reveal that PLD2 was significantly involved in BC progression through immunosuppressive pathways in the TME. We therefore focused on PLD2 and tumor-associated macrophages (TAMs), which were increased in Pld2-KO mice and further associated with poor prognoses in BC patients. In vitro, we found that Pld2-KO mouse TAMs had significantly enhanced proliferation, correlating closely with increased interleukin-1β (IL-1β) production. These results indicate that PLD2 suppresses BC progression by regulation of IL-1β secretion from TAMs in the TME, suggesting that PLD2 could serve as a potential therapeutic target for modifying the TME in BC.

Nivolumab combination therapies in patients with advanced gastric and gastroesophageal junction cancer: the phase II FRACTION gastric cancer study

BACKGROUND

Nivolumab-based therapies are efficacious with acceptable safety in patients with gastric cancer (GC) and gastroesophageal junction cancer (GEJC). Novel nivolumab-based combination immunotherapies may offer enhanced efficacy in these indications. FRACTION-GC was a signal-seeking, randomized, open-label, phase II adaptive-design trial assessing efficacy and safety of nivolumab in combination with ipilimumab [cytotoxic T lymphocyte antigen-4 (CTLA-4) antibody], relatlimab (lymphocyte-activation gene 3 antibody), or IDO1i (BMS986205, an indoleamine-2,3-dioxygenase-1 inhibitor) in patients with unresectable, advanced/metastatic GC/GEJC.

PATIENTS AND METHODS

Previously treated patients with GC/GEJC were randomized to receive nivolumab + ipilimumab, nivolumab + relatlimab, or nivolumab + IDO1i across two tracks: anti-programmed death-(ligand) 1/anti-CTLA-4-naïve (track 1) and -experienced (track 2). Primary endpoints were objective response rate (ORR) by investigator per RECIST v1.1, duration of response, and progression-free survival (PFS) rate at 24 weeks. Secondary endpoint was safety.

RESULTS

Eighty-one patients in track 1 and 81 in track 2 received one combination therapy. With a median follow-up of 50.2 months, ORR [95% confidence interval (CI)] by investigator for nivolumab + ipilimumab, nivolumab + relatlimab, and nivolumab + IDO1i in track 1 was 4% (0.1% to 21.9%), 5% (0.1% to 24.9%), and 13% (4.4% to 28.1%), and for track 2 was 9% (1.1% to 28.0%), 6% (0.7% to 18.7%), and 0% (0% to 15.4%), respectively. PFS rate at 24 weeks (95% CI) was 24% (11% to 39%) for nivolumab + IDO1i track 1, 17% (16% to 32%) for nivolumab + relatlimab track 2, and not estimable for other treatment arms. Grade 3/4 treatment-related adverse events were reported in 22%, 5%, and 18% of patients receiving nivolumab + ipilimumab, nivolumab + relatlimab, and nivolumab + IDO1i in track 1 and in 35%, 11%, and 18% of patients in track 2, respectively. No treatment-related deaths were reported.

CONCLUSIONS

While ORR did not meet prespecified expansion criteria in any treatment arm, the safety profile of the combinations was manageable. FRACTION-GC represents a novel adaptive protocol for testing multiple combination immunotherapies.

CCR8: a promising therapeutic target against tumor-infiltrating regulatory T cells

Tumor-infiltrating regulatory T (TI-Treg) cells constitute key components within the tumor microenvironment (TME) to suppress antitumor immunity and facilitate tumor progression. Although multiple therapies have been developed to eliminate TI-Treg cells, most of them exhibit only modest efficacy and harbor risks of inducing immune-related adverse events (irAEs). Recent studies demonstrate that CC chemokine receptor (CCR)8 is highly and specifically expressed on effector TI-Treg cells in mice and humans, highlighting CCR8 as a promising target for selective TI-Treg cell depletion in the treatment of various cancers. Here, we concentrate on the latest understanding of CCR8 regarding its expression, functions, and regulation, and summarize the current landscape of CCR8-targeted therapies. With favorable efficacy and safety, the latter represent an important class of next-generation putative cancer immunotherapies.