Paneth cell differentiation associated with neoadjuvant therapy in esophageal adenocarcinoma.

OBJECTIVES: Paneth cells and Paneth cell metaplasia are well-known in pathology as foundational components in the gastrointestinal system. When within malignant cells (Paneth cell differentiation [PCD]), however, the function and significance of these cells is less well understood. Here, we present findings from the first study focused on PCD in postneoadjuvant esophageal adenocarcinoma (EAC) resection specimens. METHODS: Patients with EAC treated with neoadjuvant chemoradioation and followed by esophagectomy between 2012 and 2018 in our institution were retrospectively evaluated. A tissue microarray was constructed, and special and immunohistochemical stains were performed. RESULTS: A total of 64 cases were collected, of which 8 had PCD, as highlighted by periodic acid-Schiff with diastase staining. Adenocarcinomas with PCD were more commonly seen in patients 60 to 70 years of age and typically had a poorly differentiated morphology, observationally fewer stromal mucinous changes, and less lymph node metastasis. ß-catenin activation induced by neoadjuvant therapy was more frequent in the PCD-positive cases. Patients with PCD-positive disease had low programmed cell death 1 ligand 1 levels, no positive or equivocal ERBB2 (HER2) expression, and low CD8-positive T-cell infiltration; they were also mismatch repair proficient. Patients with PCD-positive disease showed a survival pattern inferior to that of patients with PCD-negative disease. CONCLUSIONS: When induced by neoadjuvant therapy in EAC, PCD is associated with high ß-catenin activation, less expression of targetable biomarkers, and a potentially worse clinical prognosis.

The cytokine Meteorin-like inhibits anti-tumor CD8+ T cell responses by disrupting mitochondrial function.

Tumor-infiltrating lymphocyte (TIL) hypofunction contributes to the progression of advanced cancers and is a frequent target of immunotherapy. Emerging evidence indicates that metabolic insufficiency drives T cell hypofunction during tonic stimulation, but the signals that initiate metabolic reprogramming in this context are largely unknown. Here, we found that Meteorin-like (METRNL), a metabolically active cytokine secreted by immune cells in the tumor microenvironment (TME), induced bioenergetic failure of CD8+ T cells. METRNL was secreted by CD8+ T cells during repeated stimulation and acted via both autocrine and paracrine signaling. Mechanistically, METRNL increased E2F-peroxisome proliferator-activated receptor delta (PPARδ) activity, causing mitochondrial depolarization and decreased oxidative phosphorylation, which triggered a compensatory bioenergetic shift to glycolysis. Metrnl ablation or downregulation improved the metabolic fitness of CD8+ T cells and enhanced tumor control in several tumor models, demonstrating the translational potential of targeting the METRNL-E2F-PPARδ pathway to support bioenergetic fitness of CD8+ TILs.

Artesunate induces melanoma cell ferroptosis and augments antitumor immunity through targeting Ido1.

Artesunate (ART), a natural product isolated from traditional Chinese plant Artemisia annua, has not been extensively explored for its anti-melanoma properties. In our study, we found that ART inhibited melanoma cell proliferation and induced melanoma cell ferroptosis. Mechanistic study revealed that ART directly targets Ido1, thereby suppressing Hic1-mediated transcription suppression of Hmox1, resulting in melanoma cell ferroptosis. In CD8+ T cells, ART does not cause cell ferroptosis due to the low expression of Hmox1. It also targets Ido1, elevating tryptophan levels, which inhibits NFATc1-mediated PD1 transcription, consequently activating CD8+ T cells. Our study uncovered a potent and synergistic anti-melanoma efficacy arising from ART-induced melanoma cell ferroptosis and concurrently enhancing CD8+ T cell-mediated immune response both in vivo and in vitro through directly targeting Ido1. Our study provides a novel mechanistic basis for the utilization of ART as an Ido1 inhibitor and application in clinical melanoma treatment.

Babaodan inhibits cell proliferation and metastasis and enhances anti-tumor effects of camrelizumab by inhibiting M2 phenotype macrophages in hepatocellular carcinoma.

ETHNOPHARMACOLOGICAL RELEVANCE: Babaodan (BBD) is a unique Chinese medication utilized in traditional Chinese medicine. It can eliminate toxins, induce diuresis, and eliminate yellowish hue. In addition to treating acute and chronic viral hepatitis, cholecystitis, cholangitis, and urinary tract infections, BBD has garnered popularity as a substitution treatment for several malignant cancers, particularly hepatocellular carcinoma (HCC). AIM OF THE STUDY: To elucidate the efficacy and mechanism of BBD alone and combined with camrelizumab (CLM) for treating HCC. METHODS: We investigated the effects of BBD on the HCC tumor microenvironment in vivo. Furthermore, we evaluated its effects on tumor growth and metastasis induced by M2 macrophages in vitro. RESULTS: In a mouse model of orthotopic HCC, BBD decreased tumor growth. Furthermore, it increased the M1/M2 macrophage ratio and CD8+ T-cell abundance in mice. In addition, BBD reversed HCC cell proliferation and metastasis induced by M2 macrophages, increased the anti-HCC effect of low-dose CLM, and attenuated organ damage induced by high-dose CLM. Lastly, BBD enhanced the efficacy of CLM via the PI3K/AKT/mTOR signaling pathway. CONCLUSION: BBD increases the antitumor effect of CLM by modulating the tumor immune microenvironment and attenuating its the toxic side effects of CLM.

Development and Validation of an Immune Prognostic Index Related to Infiltration of CD4+ and CD8+ T Cells in Colorectal Cancer.

Colorectal cancer (CRC) is a highly prevalent cancer worldwide, but treatment outcomes can vary significantly among patients with similar clinical or historical stages. This study aimed to investigate the differences in immune cell abundance associated with malignant progression in CRC patients. We utilized data from patients with CRC obtained from The Cancer Genome Atlas as our training set. To assess immune cell infiltration levels, an immune cell risk score (ICRS) was calculated. Furthermore, we performed network analysis to identify effective T cell-related genes (ETRGs) and subsequently constructed an effective T cell prognostic index (ETPI). The performance of the ETPI was evaluated through external validation using four Gene Expression Omnibus datasets. Additionally, a nomogram analysis and drug sensitivity analysis were conducted to explore the clinical utility of the ETRGs. We also examined the expression of ETRGs in clinical samples. Based on the ICRS, we identified activated CD4+ and CD8+ T cells as protective factors in terms of prognosis. Six ETRGs were identified to develop the ETPI, which exhibited remarkable prognostic performance. In the external validation of immunotherapy, the low ETPI group demonstrated a significantly lower recurrence rate. To optimize therapeutic strategies, we developed a nomogram. Notably, patients with different ETPI values exhibited varying responses to tumor pathway inhibitors. Finally, we observed higher protein expression of certain ETRGs in normal tissues compared to tumors. Our findings suggest that the ETPI may contribute to the precise selection of patients based on tumor microenvironment and key genomic landscape interactions, thereby optimizing drug benefits and informing clinical strategies in future.

Overexpression of LAG-3: a potential indicator of low immune function in tuberculosis.

Background: Tuberculosis (TB) persists as a global health challenge, with its treatment hampered by the side effects of long-term combination drug therapies and the growing issue of drug resistance. Therefore, the development of novel therapeutic strategies is critical. This study focuses on the role of immune checkpoint molecules (ICs) and functions of CD8+ T cells in the search for new potential targets against TB. Methods: We conducted differential expression genes analysis and CD8+ T cell functional gene analysis on 92 TB samples and 61 healthy individual (HI) samples from TB database GSE83456, which contains data on 34,603 genes. The GSE54992 dataset was used to validated the findings. Additionally, a cluster analysis on single-cell data from primates infected with mycobacterium tuberculosis and those vaccinated with BCG was performed. Results: The overexpression of LAG-3 gene was found as a potentially important characteristic of both pulmonary TB (PTB) and extrapulmonary TB (EPTB). Further correlation analysis showed that LAG-3 gene was correlated with GZMB, perforin, IL-2 and IL-12. A significant temporal and spatial variation in LAG-3 expression was observed in T cells and macrophages during TB infection and after BCG vaccination. Conclusion: LAG-3 was overexpressed in TB samples. Targeting LAG-3 may represent a potential therapeutic target for tuberculosis.

An in vitro CD8 T-cell priming assay enables epitope selection for hepatitis C virus vaccines.

For the rational design of epitope-specific vaccines, identifying epitopes that can be processed and presented is essential. As algorithm-based epitope prediction is frequently discordant with actually recognized CD8+ T-cell epitopes, we developed an in vitro CD8 T-cell priming protocol to enable the identification of truly and functionally expressed HLA class I epitopes. The assay was established and validated to identify epitopes presented by hepatitis C virus (HCV)-infected cells. In vitro priming of naïve CD8 T cells was achieved by culturing unfractionated PBMCs in the presence of a specific cocktail of growth factors and cytokines, and next exposing the cells to hepatic cells expressing the NS3 protein of HCV. After a 10-day co-culture, HCV-specific T-cell responses were identified based on IFN-γ ELISpot analysis. For this, the T cells were restimulated with long synthetic peptides (SLPs) spanning the whole NS3 protein sequence allowing the identification of HCV-specificity. We demonstrated that this protocol resulted in the in vitro priming of naïve precursors to antigen-experienced T-cells specific for 11 out of 98 SLPs tested. These 11 SLPs contain 12 different HLA-A*02:01-restricted epitopes, as predicted by a combination of three epitope prediction algorithms. Furthermore, we identified responses against 3 peptides that were not predicted to contain any immunogenic HLA class I epitopes, yet showed HCV-specific responses in vitro. Separation of CD8+ and CD8- T cells from PBMCs primed in vitro showed responses only upon restimulation with short peptides. We established an in vitro method that enables the identification of HLA class I epitopes resulting from cross-presented antigens and that can cross-prime T cells and allows the effective selection of functional immunogenic epitopes, but also less immunogenic ones, for the design of tailored therapeutic vaccines against persistent viral infections and tumor antigens.

CBX4 suppresses CD8+ T cell antitumor immunity by reprogramming glycolytic metabolism.

Rationale: CD8+ T cells undergo a series of metabolic reprogramming processes during their activation and proliferation, including increased glycolysis, decreased aerobic oxidation of sugars, increased amino acid metabolism and increased protein synthesis. However, it is still unclear what factors regulate these metabolic reprogramming processes in CD8+ T cells in the tumor immune microenvironment. Methods: T cell chromobox protein 4 (CBX4) knock-out mice models were used to determine the role of CBX4 in CD8+ T cells on the tumor immune microenvironment and tumor progression. Flow cytometry, Cut-Tag qPCR, Chip-seq, immunoprecipitation, metabolite detection, lentivirus infection and adoptive T cells transfer were performed to explore the underlying mechanisms of CBX4 knock-out in promoting CD8+ T cell activation and inhibiting tumor growth. Results: We found that CBX4 expression was induced in tumor-infiltrating CD8+ T cells and inhibited CD8+ T cell function by regulating glucose metabolism in tumor tissue. Mechanistically, CBX4 increases the expression of the metabolism-associated molecule aldolase B (Aldob) through sumoylation of trans-acting transcription factor 1 (SP1) and Krüppel-like factor 3 (KLF3). In addition, Aldob inhibits glycolysis and ATP synthesis in T cells by reducing the phosphorylation of the serine/threonine protein kinase (Akt) and ultimately suppresses CD8+ T cell function. Significantly, knocking out CBX4 may improve the efficacy of anti-PD-1 therapy by enhancing the function of CD8+ T cells in the tumor microenvironment. Conclusion: CBX4 is involved in CD8+ T cell metabolic reprogramming and functional persistence in tumor tissues, and serves as an inhibitor in CD8+ T cells' glycolysis and effector function.

Lrp10 suppresses IL7R limiting CD8 T cell homeostatic expansion and anti-tumor immunity.

Signals emanating from the T-cell receptor (TCR), co-stimulatory receptors, and cytokine receptors each influence CD8 T-cell fate. Understanding how these signals respond to homeostatic and microenvironmental cues can reveal new ways to therapeutically direct T-cell function. Through forward genetic screening in mice, we discover that loss-of-function mutations in LDL receptor-related protein 10 (Lrp10) cause naive and central memory CD8 T cells to accumulate in peripheral lymphoid organs. Lrp10 encodes a conserved cell surface protein of unknown immunological function. T-cell activation induces Lrp10 expression, which post-translationally suppresses IL7 receptor (IL7R) levels. Accordingly, Lrp10 deletion enhances T-cell homeostatic expansion through IL7R signaling. Lrp10-deficient mice are also intrinsically resistant to syngeneic tumors. This phenotype depends on dense tumor infiltration of CD8 T cells, which display increased memory cell characteristics, reduced terminal exhaustion, and augmented responses to immune checkpoint inhibition. Here, we present Lrp10 as a new negative regulator of CD8 T-cell homeostasis and a host factor that controls tumor resistance with implications for immunotherapy.

Tissue-resident memory CD103+CD8+ T cells in colorectal cancer: its implication as a prognostic and predictive liver metastasis biomarker.

BACKGROUND: Tissue-resident memory CD103+CD8+ T cells (CD103+CD8+ TRMs) are important components of anti-tumor immunity. However, the significance of CD103+CD8+ TRMs in colorectal cancer (CRC) and their advantages remain unclear. METHODS: Clinical data and specimens were used to evaluate the significance of CD103+CD8+ TRMs in CRC. A mouse subcutaneous tumorigenesis model and colony-formation assay were conducted to evaluate the anti-tumor effects of CD103+CD8+ TRMs. Finally, the infiltration density and function of CD103+CD8+ TRMs in the tumors were evaluated using flow cytometry. RESULTS: In this study, we showed that highly infiltrated CD103+CD8+ TRMs were associated with earlier clinical stage and negative VEGF expression in CRC patients and predicted a favorable prognosis for CRC/CRC liver metastases patients. Interestingly, we also found that CD103+CD8+ TRMs may have predictive potential for whether CRC develops liver metastasis in CRC. In addition, we found a positive correlation between the ratio of the number of α-SMA+ vessels to the sum of the number of α-SMA+ and CD31+ vessels in CRC, and the infiltration level of CD103+CD8+ TRMs. In addition, anti-angiogenic therapy promoted infiltration of CD103+CD8+ TRMs and enhanced their ability to secrete interferon (IFN)-γ, thus further improving the anti-tumor effect. Moreover, in vivo experiments showed that compared with peripheral blood CD8+ T cells, CD103+CD8+ TRMs infused back into the body could also further promote CD8+ T cells to infiltrate the tumor, and they had a stronger ability to secrete IFN-γ, which resulted in better anti-tumor effects. CONCLUSION: We demonstrated that CD103+CD8+ TRMs have the potential for clinical applications and provide new ideas for combined anti-tumor therapeutic strategies, such as anti-tumor angiogenesis therapy and CAR-T combined immunotherapy.

Differential impact of genetic deletion of TIGIT or PD-1 on melanoma-specific T-lymphocytes.

Immune checkpoint (IC) blockade and adoptive transfer of tumor-specific T-cells (ACT) are two major strategies to treat metastatic melanoma. Their combination can potentiate T-cell activation in the suppressive tumor microenvironment, but the autoimmune adverse effects associated with systemic injection of IC blockers persist with this strategy. ACT of tumor-reactive T-cells defective for IC expression would overcome this issue. For this purpose, PD-1 and TIGIT appear to be relevant candidates, because their co-expression on highly tumor-reactive lymphocytes limits their therapeutic efficacy within the tumor microenvironme,nt. Our study compares the consequences of PDCD1 or TIGIT genetic deletion on anti-tumor properties and T-cell fitness of melanoma-specific T lymphocytes. Transcriptomic analyses revealed down-regulation of cell cycle-related genes in PD-1KO T-cells, consistent with biological observations, whereas proliferative pathways were preserved in TIGITKO T-cells. Functional analyses showed that PD-1KO and TIGITKO T-cells displayed superior antitumor reactivity than their wild-type counterpart in vitro and in a preclinical melanoma model using immunodeficient mice. Interestingly, it appears that TIGITKO T-cells were more effective at inhibiting tumor cell proliferation in vivo, and persist longer within tumors than PD-1KO T-cells, consistent with the absence of impact of TIGIT deletion on T-cell fitness. Taken together, these results suggest that TIGIT deletion, over PD-1 deletion, in melanoma-specific T-cells is a compelling option for future immunotherapeutic strategies.

PD-L1 expression in keratinocyte and infiltration of CD4 + T lymphocyte can predict a severe type of erythema multiforme major induced by the anti-PD-1 antibody, pembrolizumab.

Skin toxicity is the most common adverse event of treatment with immune check point inhibitors. Among them, erythema multiforme is a rare occurrence with a frequency of 4%, with most of the cases developing grade 1/2 disease. We experienced high grade erythema multiforme major developing with pembrolizumab treatment for anal canal cancer with extensive skin metastases. Steroid ointment was ineffective, and the skin lesions with blisters expanded to > 45% of the body surface area. The patient was at risk for symptom aggravation, and a pulse therapy with methylprednisolone and increasing the dose of oral prednisolone (1 mg/kg) were started. The skin lesions improved in 1.8 months. Unless urgent and appropriate treatments such as high dose steroid administration were conducted, the skin toxicities could not be controlled. The presence of CD4+ T cells and PD-L1+ keratinocytes in the skin biopsy might be a predictive marker of erythema multiforme major resistant to standard steroid treatment. Supplementary Information: The online version contains supplementary material available at 10.1007/s13691-024-00676-4.

Neoadjuvant chemoimmunotherapy for small cell carcinoma of the esophagus: Clinical efficacy and biomarker exploration.

Small cell carcinoma of the esophagus (SCCE) is a rare and highly malignant type of esophageal cancer with no standard treatment, facing challenges of resistance to conventional therapies. This study presents the cases of one extensive-stage and two limited-stage SCCE patients treated with chemoimmunotherapy. The two limited-stage patients underwent surgery post-treatment and experienced notable and enduring positive responses. This represents the first documented application of neoadjuvant chemoimmunotherapy in limited-stage SCCE patients. Additionally, comprehensive immunohistochemical analysis and whole exome sequencing were performed on the case patients. The findings revealed that infiltration of CD8+ T cells and PD-L1 expression in the SCCE tumor were key factors for favorable responses in SCCE patients receiving chemoimmunotherapy.

CD8+ T cell­related KCTD5 contributes to malignant progression and unfavorable clinical outcome of patients with triple­negative breast cancer.

Triple­negative breast cancer (TNBC) is a highly aggressive and heterogeneous subtype of breast cancer that lacks expression of estrogen receptor, progesterone receptor, and HER2, making it more challenging to treat with targeted therapies. The present study aimed to identify CD8+ T cell­associated genes, which could provide insight into the mechanisms underlying TNBC to facilitate developing novel immunotherapies. TNBC datasets were downloaded from public databases including The Cancer Genome Atlas, Molecular Taxonomy of Breast Cancer International Consortium, and Gene Expression Omnibus. Candidate genes were identified integrating weighted gene co­expression network analysis (WGCNA), differential gene expression, protein­protein­interaction network construction and univariate Cox regression analysis. Kaplan­Meier survival, multivariate Cox regression and receiver operating characteristic analysis were performed to evaluate the prognostic value of hub genes. Knockdown experiments, alongside wound healing, Cell Counting Kit­8 and Transwell migration and invasion assays were performed. In total, seven gene modules were associated with CD8+ T cells using WGCNA, among which potassium channel tetramerization domain 5 (KCTD5) was significantly upregulated in TNBC samples and was associated with poor prognosis. KCTD5 expression inversely associated with infiltration ratios of 'Macrophages M1', 'Plasma cells', and 'γδ T cells', but positively with 'activated Mast cells', 'Macrophages M0', and 'Macrophages M2'. As an independent prognostic indicator for TNBC, KCTD5 was also associated with drug sensitivity and the expression of programmed cell death protein 1, Cytotoxic T­Lymphocyte­Associated Protein 4 (CTLA4), CD274), Cluster of Differentiation 86 (CD86), Lymphocyte­Activation Gene 3 (LAG3), T Cell Immunoreceptor with Ig and ITIM Domains (TIGIT). Knockdown of KCTD5 significantly inhibited viability, migration and invasion of TNBC cells in vitro. KCTD5 was suggested to impact the tumor immune microenvironment by influencing the infiltration of immune cells and may serve as a potential therapeutic target for TNBC.

Perioperative stroke deteriorates white matter integrity by enhancing cytotoxic CD8+ T-cell activation.

AIM: To explore the regulatory mechanisms of microglia-mediated cytotoxic CD8+ T-cell infiltration in the white matter injury of perioperative stroke (PIS). METHODS: Adult male C57BL/6 mice were subjected to ileocolic bowel resection (ICR) 24 h prior to permanent distant middle cerebral artery occlusion (dMCAO) to establish model PIS. White matter injury, functional outcomes, peripheral immune cell infiltration, and microglia phenotype were assessed up to 28 days after dMCAO using behavioral phenotyping, immunofluorescence staining, transmission electron microscopy, western blot, and FACS analysis. RESULTS: We found surgery aggravated white matter injury and deteriorated sensorimotor deficits up to 28 days following PIS. The PIS mice exhibited significantly increased activation of peripheral and central CD8+ T cells, while significantly reduced numbers of mature oligodendrocytes compared to IS mice. Neutralizing CD8+ T cells partly reversed the aggravated demyelination following PIS. Pharmacological blockage or genetic deletion of receptor-interacting protein kinase 1 (RIPK1) activity could alleviate CD8+ T-cell infiltration and demyelination in PIS mice. CONCLUSION: Surgery exacerbates demyelination and worsens neurological function by promoting infiltration of CD8+ T cells and microglia necroptosis, suggesting that modulating interactions of CD8+ T cells and microglia could be a novel therapeutic target of long-term neurological deficits of PIS.

Intratumoral immune triads are required for immunotherapy-mediated elimination of solid tumors.

Tumor-specific CD8+ T cells are frequently dysfunctional and unable to halt tumor growth. We investigated whether tumor-specific CD4+ T cells can be enlisted to overcome CD8+ T cell dysfunction within tumors. We find that the spatial positioning and interactions of CD8+ and CD4+ T cells, but not their numbers, dictate anti-tumor responses in the context of adoptive T cell therapy as well as immune checkpoint blockade (ICB): CD4+ T cells must engage with CD8+ T cells on the same dendritic cell during the effector phase, forming a three-cell-type cluster (triad) to license CD8+ T cell cytotoxicity and cancer cell elimination. When intratumoral triad formation is disrupted, tumors progress despite equal numbers of tumor-specific CD8+ and CD4+ T cells. In patients with pleural mesothelioma treated with ICB, triads are associated with clinical responses. Thus, CD4+ T cells and triads are required for CD8+ T cell cytotoxicity during the effector phase and tumor elimination.

Single-cell transcriptomics reveals CD8+ T cell structure and developmental trajectories in idiopathic pulmonary fibrosis.

Immune cells in the human lung are associated with idiopathic pulmonary fibrosis. However, the contribution of different immune cell subpopulations to the pathogenesis of pulmonary fibrosis remains unclear. We used single-cell RNA sequencing data to investigate the transcriptional profiles of immune cells in the lungs of 5 IPF patients and 3 subjects with non-fibrotic lungs. In an identifiable population of immune cells, we found increased percentage of CD8+ T cells in the T cell subpopulation in IPF. Monocle analyzed the dynamic immune status and cell transformation of CD8+ T cells, as well as the cytotoxicity and exhausted status of CD8+ T cell subpopulations at different stages. Among CD8+ T cells, we found differences in metabolic pathways in IPF and Ctrl, including lipid, amino acid and carbohydrate metabolic. By analyzing the metabolites of CD8+ T cells, we found that different populations of CD8+ T cells in IPF have unique metabolic characteristics, but they also have multiple identical up-regulated or down-regulated metabolites. In IPF, signaling pathways associated with fibrosis were enriched in CD8+ T cells, suggesting that CD8+ T cells may have an important contribution to fibrosis. Finally, we analyzed the interactions between CD8+ T cells and other cells. Together, these studies highlight key features of CD8+ T cells in the pathogenesis of IPF and help to develop effective therapeutic targets.

Peripheral CD8+PD-1+ T cells as novel biomarker for neoadjuvant chemoimmunotherapy in humanized mice of non-small cell lung cancer.

Neoadjuvant immunotherapy has shown promising clinical activity in the treatment of early non-small cell lung cancer (NSCLC); however, further clarification of the specific mechanism and identification of biomarkers are imperative prior to implementing it as a daily practice. The study investigated the reprogramming of T cells in both tumor and peripheral blood following neoadjuvant chemoimmunotherapy in a preclinical NSCLC mouse model engrafted with a human immune system. Samples were also collected from 21 NSCLC patients (Stage IA-IIIB) who received neoadjuvant chemoimmunotherapy, and the dynamics of potential biomarkers within these samples were measured and further subjected to correlation analysis with prognosis. Further, we initially investigated the sources of the potential biomarkers. We observed in the humanized mouse model, neoadjuvant chemoimmunotherapy could prevent postoperative recurrence and metastasis by increasing the frequency and cytotoxicity of CD8+ T cells in both peripheral blood (p < 0.001) and tumor immune microenvironment (TIME) (p < 0.001). The kinetics of peripheral CD8+PD-1+ T cells reflected the changes in the TIME and pathological responses, ultimately predicting survival outcome of mice. In the clinical cohort, patients exhibiting an increase in these T cells post-treatment had a higher rate of complete or major pathological response (p < 0.05) and increased immune infiltration (p = 0.0012, r = 0.792). We identified these T cells originating from tumor draining lymph nodes and subsequently entering the TIME. In conclusion, the kinetics of peripheral CD8+PD-1+ T cells can serve as a predictor for changes in TIME and optimal timing for surgery, ultimately reflecting the outcomes of neoadjuvant chemoimmunotherapy in both preclinical and clinical setting.

IRF4 impedes human CD8 T cell function and promotes cell proliferation and PD-1 expression.

Human CD8 tumor-infiltrating lymphocytes (TILs) with impaired effector functions and PD-1 expression are categorized as exhausted. However, the exhaustion-like features reported in TILs might stem from their activation rather than the consequence of T cell exhaustion itself. Using CRISPR-Cas9 and lentiviral overexpression in CD8 T cells from non-cancerous donors, we show that the T cell receptor (TCR)-induced transcription factor interferon regulatory factor 4 (IRF4) promotes cell proliferation and PD-1 expression and hampers effector functions and expression of nuclear factor κB (NF-κB)-regulated genes. While CD8 TILs with impaired interferon γ (IFNγ) production exhibit activation markers IRF4 and CD137 and exhaustion markers thymocyte selection associated high mobility group box (TOX) and PD-1, activated T cells in patients with COVID-19 do not demonstrate elevated levels of TOX and PD-1. These results confirm that IRF4+ TILs are exhausted rather than solely activated. Our study indicates, however, that PD-1 expression, low IFNγ production, and active cycling in TILs are all influenced by IRF4 upregulation after T cell activation.

Lactate drives the ESM1-SCD1 axis to inhibit the antitumor CD8+ T-cell response by activating the Wnt/ß-catenin pathway in ovarian cancer cells and inducing cisplatin resistance.

Ovarian cancer (OC) is a gynecological malignancy that results in a global threat to women's lives. Lactic acid, a key metabolite produced from the glycolytic metabolism of glucose molecules, is correlated with tumor immune infiltration and platinum resistance. In our previous study, we found that endothelial cell-specific molecule 1 (ESM1) plays a key role in OC progression. This study revealed that lactate could upregulate ESM1, which enhances SCD1 to attenuate the antitumor CD8+ T-cell response. ESM1 and SCD1 expression levels were significantly greater in OC patients with high lactic acid levels than in those with low lactic acid levels. Further mechanistic studies suggested that the Wnt/ß-catenin pathway was inactivated after ESM1 knockdown and rescued by SCD1 overexpression. IC50 analysis indicated that the ESM1-SCD1 axis induces the resistance of OC cells to platinum agents, including cisplatin, carboplatin, and oxaliplatin, by upregulating P-gp. In conclusion, our study indicated that the induction of SCD1 by lactic acid-induced ESM1 can impede the CD8+ T-cell response against tumors and promote resistance to cisplatin by activating the Wnt/ß-catenin pathway in ovarian cancer. Consequently, targeting ESM1 may have considerable therapeutic potential for modulating the tumor immune microenvironment and enhancing drug sensitivity in OC patients.