Checkpoint blockade cancer immunotherapy targets tumour-specific mutant antigens

Dual effects of radiotherapy on tumor microenvironment and its contribution towards the development of resistance to immunotherapy in gastrointestinal and thoracic cancers

Successful clinical methods for tumor elimination include a combination of surgical resection, radiotherapy, and chemotherapy. Radiotherapy is one of the crucial components of the cancer treatment regimens which allow to extend patient life expectancy. Current cutting-edge radiotherapy research is focused on the identification of methods that should increase cancer cell sensitivity to radiation and activate anti-cancer immunity mechanisms. Radiation treatment activates various cells of the tumor microenvironment (TME) and impacts tumor growth, angiogenesis, and anti-cancer immunity. Radiotherapy was shown to regulate signaling and anti-cancer functions of various TME immune and vasculature cell components, including tumor-associated macrophages, dendritic cells, endothelial cells, cancer-associated fibroblasts (CAFs), natural killers, and other T cell subsets. Dual effects of radiation, including metastasis-promoting effects and activation of oxidative stress, have been detected, suggesting that radiotherapy triggers heterogeneous targets. In this review, we critically discuss the activation of TME and angiogenesis during radiotherapy which is used to strengthen the effects of novel immunotherapy. Intracellular, genetic, and epigenetic mechanisms of signaling and clinical manipulations of immune responses and oxidative stress by radiotherapy are accented. Current findings indicate that radiotherapy should be considered as a supporting instrument for immunotherapy to limit the cancer-promoting effects of TME. To increase cancer-free survival rates, it is recommended to combine personalized radiation therapy methods with TME-targeting drugs, including immune checkpoint inhibitors.

IL-6 selectively suppresses cDC1 specification via C/EBPβ

Cytokines produced in association with tumors can impair antitumor immune responses by reducing the abundance of type 1 conventional dendritic cells (cDC1), but the mechanism remains unclear. Here, we show that tumor-derived IL-6 generally reduces cDC development but selectively impairs cDC1 development in both murine and human systems through the induction of C/EBPβ in the common dendritic cell progenitor (CDP). C/EBPβ and NFIL3 compete for binding to sites in the Zeb2 -165 kb enhancer and support or repress Zeb2 expression, respectively. At homeostasis, pre-cDC1 specification occurs upon Nfil3 induction and consequent Zeb2 suppression. However, IL-6 strongly induces C/EBPβ expression in CDPs. Importantly, the ability of IL-6 to impair cDC development is dependent on the presence of C/EBPβ binding sites in the Zeb2 -165 kb enhancer, as this effect is lost in Δ1+2+3 mutant mice in which these binding sites are mutated. These results explain how tumor-associated IL-6 suppresses cDC1 development and suggest therapeutic approaches preventing abnormal C/EBPβ induction in CDPs may help reestablish cDC1 development to enhance antitumor immunity.

Chemokine (C-X-C motif) ligand 1 maintains the immune surveillance function of natural killer cells via the PDK2/mTOR signaling pathway

Chemokine (C-X-C motif) ligand 1 (CXCL1) is mainly expressed on neutrophils and macrophages and has neutrophil chemoattractant activity. However, natural killer (NK) cells also express CXCL1. We were curious about the role played by CXCL1 in NK cells. Knocking out CXCL1 in hematopoietic cells does not affect the occurrence of NK cells; however, it does hinder NK cell maturity. CXCL1 deletion enhances the expression of immature markers and decreases the expression of functional markers in NK cells, which may explain why it hinders the maturation of NK cells. Specific knockout of CXCL1 in NK cells (CXCL1flox/flox Ncr1-cre) leads to impaired IFN-γ production and degranulation of NK cells. The lack of CXCL1 may prevent IFN-γ production and degranulation of NK cells by inhibiting the phosphorylation of AKTS473 and S6. Therefore, we have discovered a new role for CXCL1 in regulating NK cell development and immune surveillance, providing a novel theoretical basis for immunotherapy based on NK cells and potential therapeutic targets for the clinical use of NK cells. 1. Knockout of CXCL1 in hematopoietic cells inhibits the maturation of NK cells. 2. Knockout of CXCL1 in NK cells inhibits the clearance of lymphoma by NK cells and reduces IFN-γ production and CD107 expression in NK cells. 3. CXCL1 activates the PKD2/mTOR signaling pathway, and promotes the production of IFN-γ and the expression of CD107a in NK cells.

Resistance to immune checkpoint therapies by tumour-induced T-cell desertification and exclusion: key mechanisms, prognostication and new therapeutic opportunities

Immune checkpoint therapies (ICT) can reinvigorate the effector functions of anti-tumour T cells, improving cancer patient outcomes. Anti-tumour T cells are initially formed during their first contact (priming) with tumour antigens by antigen-presenting cells (APCs). Unfortunately, many patients are refractory to ICT because their tumours are considered to be 'cold' tumours-i.e., they do not allow the generation of T cells (so-called 'desert' tumours) or the infiltration of existing anti-tumour T cells (T-cell-excluded tumours). Desert tumours disturb antigen processing and priming of T cells by targeting APCs with suppressive tumour factors derived from their genetic instabilities. In contrast, T-cell-excluded tumours are characterised by blocking effective anti-tumour T lymphocytes infiltrating cancer masses by obstacles, such as fibrosis and tumour-cell-induced immunosuppression. This review delves into critical mechanisms by which cancer cells induce T-cell 'desertification' and 'exclusion' in ICT refractory tumours. Filling the gaps in our knowledge regarding these pro-tumoral mechanisms will aid researchers in developing novel class immunotherapies that aim at restoring T-cell generation with more efficient priming by APCs and leukocyte tumour trafficking. Such developments are expected to unleash the clinical benefit of ICT in refractory patients.

Differences in Receipt of Immunotherapy Treatment Among Patients With Head and Neck Cancer

Importance

The US Food and Drug Administration approved immune checkpoint inhibitors (immunotherapy) for select cases of head and neck squamous cell carcinoma (HNSCC) in 2016. However, it is unclear whether there are clinical or sociodemographic differences among patients receiving immunotherapy as part of their care. Given the known disparities in head and neck cancer care, we hypothesized that there are differences in receipt of immunotherapy among patients with HNSCC based on clinical and nonclinical characteristics.

Objective

To characterize clinical and nonclinical factors associated with receipt of immunotherapy among older patients with HNSCC.

Design, Setting, and Participants

This retrospective cohort study included patients 65 years or older diagnosed with HNSCC (n = 4860) in a community oncology care setting. Electronic health records from Navigating Cancer were assessed from January 1, 2017, to April 30, 2022.

Main Outcomes and Measures

Multivariable logistic regression was used to characterize clinical (tumor stage [localized vs advanced] and anatomical subsite [oropharyngeal vs nonoropharyngeal]) and nonclinical (age, smoking history, race and ethnicity, sex, and marital status) factors associated with receipt of immunotherapy.

Results

In the study cohort of 4860 patients, 3593 (73.9%) were men; 4230 (87.0%) were White and 630 (13.0%) were of other races. A total of 552 patients (11.4%) had received immunotherapy. After adjusting for covariates, in the final model, White patients with HNSCC had 80% increased odds of receiving immunotherapy (adjusted odds ratio [AOR], 1.80 [95% CI, 1.30-2.48]) compared with patients of other races. There were no statistically significant differences in the odds of receiving immunotherapy based on age, sex, or smoking history. Patients with nonoropharyngeal disease were significantly more likely to receive immunotherapy than those with oropharyngeal cancer (AOR, 1.29 [95% CI, 1.05-1.59]), as were those with advanced compared with local disease (AOR, 2.39 [95% CI, 1.71-3.34]).

Conclusions and Relevance

The findings of this cohort study suggest that among older patients with HNSCC, White patients may be more likely to receive immunotherapy as part of their care. Equitable access to immunotherapy and other treatment options will reduce cancer-related health disparities and improve survival of patients with HNSCC.

Intratumoral CD103+ CD8+ T cells predict response to neoadjuvant chemoimmunotherapy in advanced head and neck squamous cell carcinoma

BACKGROUND

Immune cell heterogenicity is known to determine the therapeutic response to cancer progression. Neoadjuvant chemoimmunotherapy (NACI) has shown clinical benefits in some patients with advanced head and neck squamous cell carcinoma (HNSCC), but the underlying mechanism behind this clinical response is unknown. The efficacy of NACI needs to be potentiated by identifying accurate biomarkers to predict clinical responses. Here, we attempted to identify molecules predicting NACI response in advanced HNSCC.

METHODS

We performed combined single-cell RNA sequencing (scRNA-seq) and multiplex immunofluorescence (mIHC) staining with tumor samples derived from NACI-treated HNSCC patients to identify a new tumor-infiltrating cell (TIL) subtype, CD103+ CD8+ TILs, associated with clinical response, while both in vitro and in vivo assays were carried out to determine its antitumor efficiency. The regulatory mechanism of the CD103+ CD8+ TILs population was examined by performing cell-cell interaction analysis of the scRNA-seq data and spatial analysis of the mIHC images.

RESULTS

We established intratumoral CD103+ CD8+ TILs density as a determinant of NACI efficacy in cancers. Our scRNA-seq results indicated that the population of CD103+ CD8+ TILs was dramatically increased in the responders of NACI-treated HNSCC patients, while mIHC analysis confirmed the correlation between intratumoral CD103+ CD8+ TILs density and NACI efficacy in HNSCC patients. Further receiver operating characteristic curve analysis defined this TIL subset as a potent marker to predict patient response to NACI. Functional assays showed that CD103+ CD8+ TILs were tumor-reactive T cells, while programmed cell death protein-1 (PD-1) blockade enhanced CD103+ CD8+ TILs cytotoxicity against tumor growth in vivo. Mechanistically, targeting the triggering receptor expressed on myeloid cells 2-positive (TREM2+ ) macrophages might enhance the population of CD103+ CD8+ TILs and facilitate antitumor immunity during NACI treatment.

CONCLUSIONS

Our study highlights the impact of intratumoral CD103+ CD8+ TILs density on NACI efficacy in different cancers, while the efforts to elevate its population warrant further clinical investigation.

Recent progress of metal-based nanomaterials with anti-tumor biological effects for enhanced cancer therapy

Metal-based nanomaterials have attracted broad attention recently due to their unique biological physical and chemical properties after entering tumor cells, namely biological effects. In particular, the abilities of Ca2+ to modulate T cell receptors activation, K+ to regulate stem cell differentiation, Mn2+ to activate the STING pathway, and Fe2+/3+ to induce tumor ferroptosis and enhance catalytic therapy, make the metal ions and metal-based nanomaterials play crucial roles in the cancer treatments. Therefore, due to the superior advantages of metal-based nanomaterials and the characteristics of the tumor microenvironment, we will summarize the recent progress of the anti-tumor biological effects of metal-based nanomaterials. Based on the different effects of metal-based nanomaterials on tumor cells, this review mainly focuses on the following five aspects: (1) metal-enhanced radiotherapy sensitization, (2) metal-enhanced catalytic therapy, (3) metal-enhanced ferroptosis, (4) metal-enhanced pyroptosis, and (5) metal-enhanced immunotherapy. At the same time, the shortcomings of the biological effects of metal-based nanomaterials on tumor therapy are also discussed, and the future research directions have been prospected. The highlights of promising biosafety, potent efficacy on biological effects for tumor therapy, and the in-depth various biological effects mechanism studies of metal-based nanomaterials provide novel ideas for the future biological application of the nanomaterials.

Tumor Vaccines: Unleashing the Power of the Immune System to Fight Cancer

This comprehensive review delves into the rapidly evolving arena of cancer vaccines. Initially, we examine the intricate constitution of the tumor microenvironment (TME), a dynamic factor that significantly influences tumor heterogeneity. Current research trends focusing on harnessing the TME for effective tumor vaccine treatments are also discussed. We then provide a detailed overview of the current state of research concerning tumor immunity and the mechanisms of tumor vaccines, describing the complex immunological processes involved. Furthermore, we conduct an exhaustive analysis of the contemporary research landscape of tumor vaccines, with a particular focus on peptide vaccines, DNA/RNA-based vaccines, viral-vector-based vaccines, dendritic-cell-based vaccines, and whole-cell-based vaccines. We analyze and summarize these categories of tumor vaccines, highlighting their individual advantages, limitations, and the factors influencing their effectiveness. In our survey of each category, we summarize commonly used tumor vaccines, aiming to provide readers with a more comprehensive understanding of the current state of tumor vaccine research. We then delve into an innovative strategy combining cancer vaccines with other therapies. By studying the effects of combining tumor vaccines with immune checkpoint inhibitors, radiotherapy, chemotherapy, targeted therapy, and oncolytic virotherapy, we establish that this approach can enhance overall treatment efficacy and offset the limitations of single-treatment approaches, offering patients more effective treatment options. Following this, we undertake a meticulous analysis of the entire process of personalized cancer vaccines, elucidating the intricate process from design, through research and production, to clinical application, thus helping readers gain a thorough understanding of its complexities. In conclusion, our exploration of tumor vaccines in this review aims to highlight their promising potential in cancer treatment. As research in this field continues to evolve, it undeniably holds immense promise for improving cancer patient outcomes.

Tumor Abnormality-Oriented Nanomedicine Design

Anticancer nanomedicines have been proven effective in mitigating the side effects of chemotherapeutic drugs. However, challenges remain in augmenting their therapeutic efficacy. Nanomedicines responsive to the pathological abnormalities in the tumor microenvironment (TME) are expected to overcome the biological limitations of conventional nanomedicines, enhance the therapeutic efficacies, and further reduce the side effects. This Review aims to quantitate the various pathological abnormalities in the TME, which may serve as unique endogenous stimuli for the design of stimuli-responsive nanomedicines, and to provide a broad and objective perspective on the current understanding of stimuli-responsive nanomedicines for cancer treatment. We dissect the typical transport process and barriers of cancer drug delivery, highlight the key design principles of stimuli-responsive nanomedicines designed to tackle the series of barriers in the typical drug delivery process, and discuss the "all-into-one" and "one-for-all" strategies for integrating the needed properties for nanomedicines. Ultimately, we provide insight into the challenges and future perspectives toward the clinical translation of stimuli-responsive nanomedicines.

Bioorthogonal Reaction-Mediated Tumor-Selective Delivery of CRISPR/Cas9 System for Dual-Targeted Cancer Immunotherapy

CRISPR system-assisted immunotherapy is an attractive option in cancer therapy. However, its efficacy is still less than expected due to the limitations in delivering the CRISPR system to target cancer cells. Here, we report a new CRISPR/Cas9 tumor-targeting delivery strategy based on bioorthogonal reactions for dual-targeted cancer immunotherapy. First, selective in vivo metabolic labeling of cancer and activation of the cGAS-STING pathway was achieved simultaneously through tumor microenvironment (TME)-biodegradable hollow manganese dioxide (H-MnO2 ) nano-platform. Subsequently, CRISPR/Cas9 system-loaded liposome was accumulated within the modified tumor tissue through in vivo click chemistry, resulting in the loss of protein tyrosine phosphatase N2 (PTPN2) and further sensitizing tumors to immunotherapy. Overall, our strategy provides a modular platform for precise gene editing in vivo and exhibits potent antitumor response by boosting innate and adaptive antitumor immunity.

Immune checkpoint inhibitors in EGFR-mutant non-small cell lung cancer: A systematic review

BACKGROUND

Since their first introduction in clinical practice, immune checkpoint inhibitors showed limited benefit in patients with NSCLC harboring EGFR mutations. With the rationale of increasing immune activation, combinatorial ICI strategies have been evaluated also in this subgroup of patients.

METHODS

We performed a systematic review on efficacy of ICI-based strategies in EGFR-mutant NSCLC according to most updated evidence.

RESULTS

Overall, ICI monotherapy and ICI plus chemotherapy confirm to be ineffective in EGFR-mutant NSCLC, whereas the combination of ICI with antiangiogenic and chemotherapy showed promising results. Limited data are available with alternative ICI combination strategies, driven by strong biological rationale of modulating the tumor immune microenvironment.

CONCLUSIONS

To date, the available evidence do not support the use of ICI in patients with NSCLC harboring EGFR mutations. Clinical trials are ongoing to define which is the best timing and exploring novel combinations with ICI in this specific disease.

Genetically Engineered-Cell-Membrane Nanovesicles for Cancer Immunotherapy

The advent of immunotherapy has marked a new era in cancer treatment, offering significant clinical benefits. Cell membrane as drug delivery materials has played a crucial role in enhancing cancer therapy because of their inherent biocompatibility and negligible immunogenicity. Different cell membranes are prepared into cell membrane nanovesicles (CMNs), but CMNs have limitations such as inefficient targeting ability, low efficacy, and unpredictable side effects. Genetic engineering has deepened the critical role of CMNs in cancer immunotherapy, enabling genetically engineered-CMN (GCMN)-based therapeutics. To date, CMNs that are surface modified by various functional proteins have been developed through genetic engineering. Herein, a brief overview of surface engineering strategies for CMNs and the features of various membrane sources is discussed, followed by a description of GCMN preparation methods. The application of GCMNs in cancer immunotherapy directed at different immune targets is addressed as are the challenges and prospects of GCMNs in clinical translation.

Linked CD4+/CD8+ T cell neoantigen vaccination overcomes immune checkpoint blockade resistance and enables tumor regression

Therapeutic benefit to immune checkpoint blockade (ICB) is currently limited to the subset of cancers thought to possess a sufficient tumor mutational burden (TMB) to allow for the spontaneous recognition of neoantigens (NeoAg) by autologous T cells. We explored whether the response to ICB of an aggressive low-TMB squamous cell tumor could be improved through combination immunotherapy using functionally defined NeoAg as targets for endogenous CD4+ and CD8+ T cells. We found that, whereas vaccination with CD4+ or CD8+ NeoAg alone did not offer prophylactic or therapeutic immunity, vaccines containing NeoAg recognized by both subsets overcame ICB resistance and led to the eradication of large established tumors that contained a subset of PD-L1+ tumor-initiating cancer stem cells (tCSC), provided the relevant epitopes were physically linked. Therapeutic CD4+/CD8+ T cell NeoAg vaccination produced a modified tumor microenvironment (TME) with increased numbers of NeoAg-specific CD8+ T cells existing in progenitor and intermediate exhausted states enabled by combination ICB-mediated intermolecular epitope spreading. We believe that the concepts explored herein should be exploited for the development of more potent personalized cancer vaccines that can expand the range of tumors treatable with ICB.

Antigen presentation in cancer - mechanisms and clinical implications for immunotherapy

Over the past decade, the emergence of effective immunotherapies has revolutionized the clinical management of many types of cancers. However, long-term durable tumour control is only achieved in a fraction of patients who receive these therapies. Understanding the mechanisms underlying clinical response and resistance to treatment is therefore essential to expanding the level of clinical benefit obtained from immunotherapies. In this Review, we describe the molecular mechanisms of antigen processing and presentation in tumours and their clinical consequences. We examine how various aspects of the antigen-presentation machinery (APM) shape tumour immunity. In particular, we discuss genomic variants in HLA alleles and other APM components, highlighting their influence on the immunopeptidomes of both malignant cells and immune cells. Understanding the APM, how it is regulated and how it changes in tumour cells is crucial for determining which patients will respond to immunotherapy and why some patients develop resistance. We focus on recently discovered molecular and genomic alterations that drive the clinical outcomes of patients receiving immune-checkpoint inhibitors. An improved understanding of how these variables mediate tumour-immune interactions is expected to guide the more precise administration of immunotherapies and reveal potentially promising directions for the development of new immunotherapeutic approaches.

The CD73 is induced by TGF-β1 triggered by nutrient deprivation and highly expressed in dedifferentiated human melanoma

CD73 is the key enzyme in the generation of extracellular adenosine, a mediator involved in tumor progression, tumor immune escape and resistance to anti-cancer therapeutics. Microenvironmental conditions influence the expression of CD73 in tumor cells. However how CD73 expression and activity is regulated in a stress condition of lower nutrient availability are largely unknown. Our results indicate that serum starvation leads to a marked up-regulation of CD73 expression on A375 melanoma cells in a time-dependent manner. The cell-surface expression of CD73 is associated with an increased release of TGF-β1 by starved cells. Blockade of TGF-β1 receptors or TGFβ/SMAD3 signaling pathway significantly reduce the expression of CD73 induced by starvation. Treatment of cells with rTGF-β1 up-regulates the expression of CD73 in a concentration-dependent manner, confirming the role of this pathway in regulating CD73 in melanoma A375 cells. The increased expression of CD73 is associated with enhanced AMPase activity, which is selectively reduced by inhibitors of CD73 activity, APCP and PSB-12489. Pharmacological blockade of CD73 significantly inhibits invasion of melanoma cells in a transwell system. Furthermore, using multiplex immunofluorescence imaging we found that, within human melanoma metastases, tumor cells at the dedifferentiated stage show the highest CD73 protein expression. In summary, our data provide new insights into the mechanism regulating the expression/activity of CD73 in melanoma cells in a condition of lower availability of nutrients, which is a common feature of the tumor microenvironment. Within human metastatic melanoma tissues elevated protein expression of CD73 is associated with an invasive-like phenotype.

Tandem CAR-T cells targeting MUC1 and PSCA combined with anti-PD-1 antibody exhibit potent preclinical activity against non-small cell lung cancer

Chimeric antigen receptor (CAR)-T cells encounter many issues when treating solid tumors, including tumor antigen heterogeneity and immunosuppression. United targeting of two tumor-associated antigens (TAAs) and blocking of PD-1 may solve this problem and enhance the function of CAR-T. Mucin 1 (MUC1) and prostate stem cell antigen (PSCA) are overexpressed in non-small cell lung cancer (NSCLC). Here, we constructed a bivalent tandem CAR-T (Tan CAR-T), which can simultaneously target MUC1 and PSCA and evaluated its effects of inhibiting non-small cell lung cancer (NSCLC) in vitro and in vivo. Results indicated that the tumor killing effect of these Tan CAR-T was more effective than that of single-target CAR-T, its antitumor efficacy could be further strengthened by anti-PD-1 antibody. Our study reported a previously unstudied therapeutic effect of a Tan CAR-T in NSCLC, providing a preclinical rationale for anti-PD-1 antibody combined with Tan CAR-T targeting MUC1 and PSCA in the treatment of NSCLC.

Tumor-Specific CD8+ T Cells from the Bone Marrow Resist Exhaustion and Exhibit Increased Persistence in Tumor-Bearing Hosts as Compared to Tumor Infiltrating Lymphocytes

Immunotherapy is now an integral aspect of cancer therapy. Strategies employing adoptive cell therapy (ACT) have seen the establishment of chimeric antigen receptor (CAR)-T cells using peripheral blood lymphocytes as well as tumor infiltrating lymphocytes (TILs) with significant clinical results. Despite these successes, the limitations of the current strategies are also emerging and novel approaches are needed. The bone marrow (BM) is an immunological niche that houses T cells with specificity for previously encountered antigens, including tumor-associated antigens from certain solid cancers. This study sought to improve our understanding of tumor-specific BM T cells in the context of solid tumors by comparing them with TILs, and to assess whether there is a rationale for using the BM as a source of T cells for ACT against solid malignancies. Herein, we demonstrate that T cells from the BM appear superior to TILs as a source of cells for cellular therapy. Specifically, they possess a memory-enriched phenotype and exhibit improved effector function, greater persistence within a tumor-bearing host, and the capacity for increased tumor infiltration. Taken together, these data provide a foundation for further exploring the BM as a source of tumor-specific T cells for ACT in solid malignancies.

Comprehensive analysis of circulating cell-free RNAs in blood for diagnosing non-small cell lung cancer

Early screening and detection of non-small cell lung cancer (NSCLC) is crucial due to the significantly low survival rate in advanced stages. Blood-based liquid biopsy is non-invasive test to assistant disease diagnosis, while cell-free RNA is one of the promising biomarkers in blood. However, the disease related signatures have not been explored completely for most cell-free RNA transcriptome sequencing (cfRNA-Seq) datasets. To address this gap, we developed a comprehensive cfRNA-Seq pipeline for data analysis and constructed a machine learning model to facilitate noninvasive early diagnosis of NSCLC. The results of our study have demonstrated the identification of differential mRNA, lncRNAs and miRNAs from cfRNA-Seq, which have exhibited significant association with development and progression of lung cancer. The classifier based on gene expression signatures achieved an impressive area under the curve (AUC) of up to 0.9, indicating high specificity and sensitivity in both cross-validation and independent test. Furthermore, the analysis of T cell and B cell immune repertoire extracted from cfRNA-Seq have provided insights into the immune status of cancer patients, while the microbiome analysis has revealed distinct bacterial and viral profiles between NSCLC and normal samples. In our future work, we aim to validate the existence of cancer associated T cell receptors (TCR)/B cell receptors (BCR) and microorganisms, and subsequently integrate all identified signatures into diagnostic model to improve the prediction accuracy. This study not only provided a comprehensive analysis pipeline for cfRNA-Seq dataset but also highlights the potential of cfRNAs as promising biomarkers and models for early NSCLC diagnosis, emphasizing their importance in clinical settings.

Platinum(IV) Complexes as Inhibitors of STAT3 and Regulators of the Tumor Microenvironment To Control Breast Cancer

Interplay between breast cancer (BC) cells and the tumor microenvironment (TME) influences the outcome of cancer treatment. Aberrant activation of signal transducer and activator of transcription 3 (STAT3) promotes the interaction and causes immunosuppression and drug resistance. Platinum(IV) complexes SPP and DPP bearing pterostilbene-derived axial ligand(s) were synthesized to inhibit the JAK2-STAT3 pathway in BC cells and regulate the TME. These complexes exerted remarkable antiproliferative activity against the triple-negative BC cells, suppressed the expression of phosphorylated STAT3 and STAT3-related cyclooxygenase-2 and IL-6, and activated caspase-3 and cleaved poly ADP-ribose polymerase, preventing the repair of DNA lesions and inducing apoptosis. Furthermore, DPP promoted the maturation and antigen presentation of dendritic cells, repressed the proliferation and differentiation of myeloid-derived suppressor cells and regulatory T cells, and facilitated the expansion of T cells. As a consequence, DPP showed excellent anticancer activity against BC with almost no general toxicity in vivo as a potential chemoimmunotherapeutic agent.

Acquired resistance to anti-PD1 therapy in patients with NSCLC associates with immunosuppressive T cell phenotype

Immune checkpoint inhibitor treatment has the potential to prolong survival in non-small cell lung cancer (NSCLC), however, some of the patients develop resistance following initial response. Here, we analyze the immune phenotype of matching tumor samples from a cohort of NSCLC patients showing good initial response to immune checkpoint inhibitors, followed by acquired resistance at later time points. By using imaging mass cytometry and whole exome and RNA sequencing, we detect two patterns of resistance¨: One group of patients is characterized by reduced numbers of tumor-infiltrating CD8+ T cells and reduced expression of PD-L1 after development of resistance, whereas the other group shows high CD8+ T cell infiltration and high expression of PD-L1 in addition to markedly elevated expression of other immune-inhibitory molecules. In two cases, we detect downregulation of type I and II IFN pathways following progression to resistance, which could lead to an impaired anti-tumor immune response. This study thus captures the development of immune checkpoint inhibitor resistance as it progresses and deepens our mechanistic understanding of immunotherapy response in NSCLC.

Proteogenomic identification of an immunogenic antigen derived from human endogenous retrovirus in renal cell carcinoma

CD8+ T cells can recognize tumor antigens displayed by HLA class I molecules and eliminate tumor cells. Despite their low tumor mutation burden, immune checkpoint blockade (ICB) is often beneficial in patients with renal cell carcinoma (RCC). Here, using a proteogenomic approach, we directly and comprehensively explored the HLA class I-presenting peptidome of RCC tissues and demonstrated that the immunopeptidomes contain a small subset of peptides derived from human endogenous retroviruses (hERV). A comparison between tumor and normal kidney tissues revealed tumor-associated hERV antigens, one of which was immunogenic and recognized by host tumor-infiltrating lymphocytes (TIL). Stimulation with the hERV antigen induced reactive CD8+ T cells in healthy donor-derived (HD-derived) peripheral blood mononuclear cells (PBMC). These results highlight the presence of antitumor CD8+ T cell surveillance against hERV3895 antigens, suggesting their clinical applications in patients with RCC.

HYDIN mutation status as a potential predictor of immune checkpoint inhibitor efficacy in melanoma

BACKGROUND

The advent of immune checkpoint inhibitors (ICIs) has altered the outlook for cancer treatment. The estimation of predictive biomarkers could contribute to maximizing the benefits from ICIs treatment. Here, we explored the association between HYDIN mutations (HYDIN-MUT) in melanoma and ICIs efficacy.

METHODS

Clinical data and sequencing data from published studies were utilized to assess the association between HYDIN-MUT and the efficacy of ICIs treatment in melanoma patients.

RESULTS

Compared to other tumor types, HYDIN (36.14%) has the highest mutation rate in melanoma patients. In the anti-PD-1 treated cohort (n = 254), the HYDIN-MUT patients had a longer OS after ICIs treatment than the HYDIN wild-type (HYDIN-WT) patients (HR = 0.590 [95% CI, 0.410-0.847], P = 0.004); the objective response rate (ORR) and durable clinical benefit (DCB) were increased in patients with HYDIN-MUT (ORR = 46.25, DCB = 56.00%) compared to patients with HYDIN-WT (ORR = 30.99%, DCB = 42.76%) (ORR: P = 0.019; DCB: P = 0.060). In the anti-CTLA4 treated cohort (n = 174), HYDIN-MUT patients achieved significantly longer OS than HYDIN-WT patients (HR = 0.549 [95% CI, 0.366-0.823], P = 0.003); the proportion of ORR and DCB in HYDIN-MUT patients was significantly higher than that in HYDIN-WT patients (ORR 40.54% vs. 14.42%, P = 0.031; DCB 45.76% vs. 22.22%, P = 0.002). Further gene set enrichment analysis demonstrated that DNA repair and anti-tumor immunity were significantly enhanced in HYDIN-MUT patients.

CONCLUSIONS

HYDIN mutations are a potential predictive biomarker of ICIs efficacy in melanoma patients.

The Value of Microbes in Cancer Neoantigen Immunotherapy

Tumor neoantigens are widely used in cancer immunotherapy, and a growing body of research suggests that microbes play an important role in these neoantigen-based immunotherapeutic processes. The human body and its surrounding environment are filled with a large number of microbes that are in long-term interaction with the organism. The microbiota can modulate our immune system, help activate neoantigen-reactive T cells, and play a great role in the process of targeting tumor neoantigens for therapy. Recent studies have revealed the interconnection between microbes and neoantigens, which can cross-react with each other through molecular mimicry, providing theoretical guidance for more relevant studies. The current applications of microbes in immunotherapy against tumor neoantigens are mainly focused on cancer vaccine development and immunotherapy with immune checkpoint inhibitors. This article summarizes the related fields and suggests the importance of microbes in immunotherapy against neoantigens.

Decoupled neoantigen cross-presentation by dendritic cells limits anti-tumor immunity against tumors with heterogeneous neoantigen expression

Cancer immunotherapies, in particular checkpoint blockade immunotherapy (CBT), can induce control of cancer growth, with a fraction of patients experiencing durable responses. However, the majority of patients currently do not respond to CBT and the molecular determinants of resistance have not been fully elucidated. Mounting clinical evidence suggests that the clonal status of neoantigens (NeoAg) impacts the anti-tumor T cell response. High intratumor heterogeneity (ITH), where the majority of NeoAgs are expressed subclonally, is correlated with poor clinical response to CBT and poor infiltration with tumor-reactive T cells. However, the mechanism by which ITH blunts tumor-reactive T cells is unclear. We developed a transplantable murine lung cancer model to characterize the immune response against a defined set of NeoAgs expressed either clonally or subclonally to model low or high ITH, respectively. Here we show that clonal expression of a weakly immunogenic NeoAg with a relatively strong NeoAg increased the immunogenicity of tumors with low but not high ITH. Mechanistically we determined that clonal NeoAg expression allowed cross-presenting dendritic cells to acquire and present both NeoAgs. Dual NeoAg presentation by dendritic cells was associated with a more mature DC phenotype and a higher stimulatory capacity. These data suggest that clonal NeoAg expression can induce more potent anti-tumor responses due to more stimulatory dendritic cell:T cell interactions. Therapeutic vaccination targeting subclonally expressed NeoAgs could be used to boost anti-tumor T cell responses.

PD-L1 Blockade Peptide-Modified Polymeric Nanoparticles for Oxygen-Independent-Based Hypoxic Tumor Photo/Thermodynamic Immunotherapy

Distant metastasis of malignant tumors is considered to be the main culprit for the failure of current antitumor treatments. Conventional single treatments often exhibit limited efficacy in inhibiting tumor metastasis. Therefore, there is a growing interest in developing collaborative antitumor strategies based on photothermal therapy (PTT) and free-radical-generated photodynamic therapy (PDT), especially utilizing oxygen-independent nanoplatforms, to address this challenge. Such antitumor strategies can enhance the therapeutic outcomes by ensuring the cytotoxicity of free radicals even in the hypoxic tumor microenvironment, thereby improving the effective suppression of primary tumors. Additionally, these approaches can stimulate the production of tumor-associated antigens and amplify the immunogenic cell death (ICD) effects, potentially feasible for enhancing the therapeutic outcomes of immunotherapy. Herein, we fabricated a functional nanosystem that co-loads IR780 and 2,2'-azobis[2-(2-imidazolin-2-yl)propane]-dihydrochloride (AIPH) to realize PTT-triggered thermodynamic combination therapy via the oxygen-independent pathway for the elimination of primary tumors. Furthermore, the nanocomposites were surface-decorated with a predesigned complex peptide (PLGVRGC-anti-PD-L1 peptide, MMP-sensitive), which facilitated the immunotherapy targeting distant tumors. Through the specific recognition of matrix metalloproteinase (MMP), the sensitive segment on the obtained aNC@IR780A was cleaved. As a result, the freed anti-PD-L1 peptide effectively blocked immune checkpoints, leading to the infiltration and activation of T cells (CTLs). This nanosystem was proven to be effective at inhibiting both primary tumors and distant tumors, providing a promising combination strategy for tumor PTT/TDT/immunotherapy.

Primary and acquired resistance to first-line therapy for clear cell renal cell carcinoma

The introduction of first-line combinations had improved the outcomes for metastatic renal cell carcinoma (mRCC) compared to sunitinib. However, some patients either have inherent resistance or develop resistance as a result of the treatment. Depending on the kind of therapy employed, many factors underlie resistance to systemic therapy. Angiogenesis and the tumor immune microenvironment (TIME), nevertheless, are inextricably linked. Although angiogenesis and the manipulation of the tumor microenvironment are linked to hypoxia, which emerges as a hallmark of renal cell carcinoma (RCC) pathogenesis, it is only one of the potential elements involved in the distinctive intra- and inter-tumor heterogeneity of RCC that is still dynamic. We may be able to more correctly predict therapy response and comprehend the mechanisms underlying primary or acquired resistance by integrating tumor genetic and immunological markers. In order to provide tools for patient selection and to generate hypotheses for the development of new strategies to overcome resistance, we reviewed the most recent research on the mechanisms of primary and acquired resistance to immune checkpoint inhibitors (ICIs) and tyrosine kinase inhibitors (TKIs) that target the vascular endothelial growth factor receptor (VEGFR).We can choose patients' treatments and cancer preventive strategies using an evolutionary approach thanks to the few evolutionary trajectories that characterize ccRCC.

Induction of cancer neoantigens facilitates development of clinically relevant models for the study of pancreatic cancer immunobiology

Neoantigen burden and CD8 T cell infiltrate are associated with clinical outcome in pancreatic ductal adenocarcinoma (PDAC). A shortcoming of many genetic models of PDAC is the lack of neoantigen burden and limited T cell infiltrate. The goal of the present study was to develop clinically relevant models of PDAC by inducing cancer neoantigens in KP2, a cell line derived from the KPC model of PDAC. KP2 was treated with oxaliplatin and olaparib (OXPARPi), and a resistant cell line was subsequently cloned to generate multiple genetically distinct cell lines (KP2-OXPARPi clones). Clones A and E are sensitive to immune checkpoint inhibition (ICI), exhibit relatively high T cell infiltration, and have significant upregulation of genes involved in antigen presentation, T cell differentiation, and chemokine signaling pathways. Clone B is resistant to ICI and is similar to the parental KP2 cell line in terms of relatively low T cell infiltration and no upregulation of genes involved in the pathways noted above. Tumor/normal exome sequencing and in silico neoantigen prediction confirms successful generation of cancer neoantigens in the KP2-OXPARPi clones and the relative lack of cancer neoantigens in the parental KP2 cell line. Neoantigen vaccine experiments demonstrate that a subset of candidate neoantigens are immunogenic and neoantigen synthetic long peptide vaccines can restrain Clone E tumor growth. Compared to existing models, the KP2-OXPARPi clones better capture the diverse immunobiology of human PDAC and may serve as models for future investigations in cancer immunotherapies and strategies targeting cancer neoantigens in PDAC.

Personalized neoantigen viro-immunotherapy platform for triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) corresponds to approximately 20% of all breast tumors, with a high propensity for metastasis and a poor prognosis. Because TNBC displays a high mutational load compared with other breast cancer types, a neoantigen-based immunotherapy strategy could be effective. One major bottleneck in the development of a neoantigen-based vaccine for TNBC is the selection of the best targets, that is, tumor-specific neoantigens which are presented at the surface of tumor cells and capable of eliciting robust immune responses. In this study, we aimed to set up a platform for identification and delivery of immunogenic neoantigens in a vaccine regimen for TNBC using oncolytic vaccinia virus (VV).

METHODS

We used bioinformatic tools and cell-based assays to identify immunogenic neoantigens in TNBC patients' samples, human and murine cell lines. Immunogenicity of the neoantigens was tested in vitro (human) and ex vivo (murine) in T-cell assays. To assess the efficacy of our regimen, we used a preclinical model of TNBC where we treated tumor-bearing mice with neoantigens together with oncolytic VV and evaluated the effect on induction of neoantigen-specific CD8+T cells, tumor growth and survival.

RESULTS

We successfully identified immunogenic neoantigens and generated neoantigen-specific CD8+T cells capable of recognizing a human TNBC cell line expressing the mutated gene. Using a preclinical model of TNBC, we showed that our tumor-specific oncolytic VV was able to change the tumor microenvironment, attracting and maintaining mature cross-presenting CD8α+dendritic cells and effector T-cells. Moreover, when delivered in a prime/boost regimen together with oncolytic VV, long peptides encompassing neoantigens were able to induce neoantigen-specific CD8+T cells, slow tumor growth and increase survival.

CONCLUSIONS

Our study provides a promising approach for the development of neoantigen-based immunotherapies for TNBC. By identifying immunogenic neoantigens and developing a delivery system through tumor-specific oncolytic VV, we have demonstrated that neoantigen-based vaccines could be effective in inducing neoantigen-specific CD8+T cells response with significant impact on tumor growth. Further studies are needed to determine the safety and efficacy of this approach in clinical trials.

Knowledge mapping of therapeutic cancer vaccine from 2013 to 2022: A bibliometric and visual analysis

The investigation of therapeutic cancer vaccines has been ongoing for the past century. Herein, we used VOSviewer and CiteSpace to perform the first global bibliometric analysis of the literature on therapeutic cancer vaccines from 2013 to 2022 aiming to explore the current status and potential research trends. The findings revealed a consistent upward trend in both publication counts and citations. The United States emerged as the leading contributor with the highest number of published papers. Additionally, the analysis of references and keywords indicated that therapeutic cancer vaccines have long been popular topics, whereas neoantigen vaccines, mRNA vaccines, combination strategies, and vaccine delivery systems are emerging research hotspots. This bibliometric study provides a comprehensive and important overview of the current knowledge and potential developments in therapeutic cancer vaccines from 2013 to 2022, which may serve as a valuable reference for scholars interested in further exploring this promising field.

Mechanisms underlying response and resistance to immune checkpoint blockade in cancer immunotherapy

Cancer immunotherapies targeting immune checkpoint pathways, such as programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) and cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4), have achieved unprecedented therapeutic success in treating various types of cancer. The prominent and persistent clinical responses to immune checkpoint blockade (ICB) therapy are currently constrained to a subset of patients. Owing to discrete individual tumor and immune heterogeneity, most patients fail to benefit from ICB treatment, demonstrating either primary or acquired resistance. A thorough comprehension of the mechanisms restricting the efficacy of immune checkpoint inhibitors (ICIs) is required to extend their clinical applicability to a broader spectrum of patients and cancer types. Numerous studies are presently investigating potential prognostic markers of responsiveness, the complex dynamics underlying the therapeutic and adverse effects of ICB, and tumor immune evasion throughout the course of immunotherapy. In this article, we have reviewed the extant literature elucidating the mechanisms underlying the response and resistance to ICB, with a particular emphasis on PD-1 and CTLA-4 pathway blockade in the context of anti-tumor immunity. Furthermore, we aimed to explore potential approaches to overcome cancer therapeutic resistance and develop a rational design for more personalized ICB-based combinational regimens.

Circulating circRNA: a social butterfly in tumors

Circular RNAs (circRNAs) are a class of single-stranded non-coding RNAs that form circular structures through irregular splicing or post-splicing events. CircRNAs are abnormally expressed in many cancers and regulate the occurrence and development of tumors. Circulating circRNAs are cell-free circRNAs present in peripheral blood, they are considered promising biomarkers due to their high stability. In recent years, more and more studies have revealed that circulating circRNAs participate in various cellular communication and regulate the occurrence and development of tumors, which involve many pathological processes such as tumorigenesis, tumor-related immunity, tumor angiogenesis, and tumor metastasis. Understanding the role of cell communication mediated by circulating circRNAs in tumor will further reveal the value and significance behind their use as biomarkers and potential therapeutic targets. In this review, we summarize the recent findings and provide an overview of the cell-cell communication mediated by circulating circRNAs, aiming to explore the role and application value of circulating circRNAs in tumors.

Comprehensive analysis of neoantigens derived from structural variation across whole genomes from 2528 tumors

BACKGROUND

Neoantigens are critical for anti-tumor immunity and have been long-envisioned as promising therapeutic targets. However, current neoantigen analyses mostly focus on single nucleotide variations (SNVs) and indel mutations and seldom consider structural variations (SVs) that are also prevalent in cancer.

RESULTS

Here, we develop a computational method termed NeoSV, which incorporates SV annotation, protein fragmentation, and MHC binding prediction together, to predict SV-derived neoantigens. Analysis of 2528 whole genomes reveals that SVs significantly contribute to the neoantigen repertoire in both quantity and quality. Whereas most neoantigens are patient-specific, shared neoantigens are identified with high occurrence rates in breast, ovarian, and gastrointestinal cancers. We observe extensive immunoediting on SV-derived neoantigens, especially on clonal events, which suggests their immunogenic potential. We also demonstrate that genomic alteration-related neoantigen burden, which integrates SV-derived neoantigens, depicts the tumor-immune interplay better than tumor neoantigen burden and may improve patient selection for immunotherapy.

CONCLUSIONS

Our study fills the gap in the current neoantigen repertoire and provides a valuable resource for cancer vaccine development.

Potential Effects of Regulating Intestinal Flora on Immunotherapy for Liver Cancer

The intestinal flora plays an important role in the occurrence and development of liver cancer, affecting the efficacy and side effects of conventional antitumor therapy. Recently, immunotherapy for liver cancer has been a palliative treatment for patients with advanced liver cancer lacking surgical indications. Representative drugs include immune checkpoint inhibitors, regulators, tumor vaccines, and cellular immunotherapies. The effects of immunotherapy on liver cancer vary because of the heterogeneity of the tumors. Intestinal flora can affect the efficacy and side effects of immunotherapy for liver cancer by regulating host immunity. Therefore, applying probiotics, prebiotics, antibiotics, and fecal transplantation to interfere with the intestinal flora is expected to become an important means of assisting immunotherapy for liver cancer. This article reviews publications that discuss the relationship between intestinal flora and immunotherapy for liver cancer and further clarifies the potential relationship between intestinal flora and immunotherapy for liver cancer.

Molecular mechanisms of ferroptosis and its antitumor applications in natural products

Ferroptosis, an iron-dependent form of regulated cell death, results in lipid peroxidation of polyunsaturated fatty acids in the cell membrane, which is catalyzed by iron ions and accumulated to lethal levels. It is mechanistically distinct from other forms of cell death, such as apoptosis, pyroptosis, and necroptosis, so it may address the problem of cancer resistance to apoptosis and provide new therapeutic strategies for cancer treatment, which has been intensively studied over the past few years. Notably, considerable advances have been made in the antitumor research of natural products due to their multitargets and few side effects. According to research, natural products can also induce ferroptosis in cancer therapies. In this review we summarize the molecular mechanisms of ferroptosis, introduce the key regulatory genes of ferroptosis, and discuss the progress of natural product research in the field of ferroptosis to provide theoretical guidance for research on natural product-induced ferroptosis in tumors.

ALK peptide vaccination restores the immunogenicity of ALK-rearranged non-small cell lung cancer

Anaplastic lymphoma kinase (ALK)-rearranged non-small cell lung cancer (NSCLC) is treated with ALK tyrosine kinase inhibitors (TKIs), but the lack of activity of immune checkpoint inhibitors (ICIs) is poorly understood. Here, we identified immunogenic ALK peptides to show that ICIs induced rejection of ALK+ tumors in the flank but not in the lung. A single-peptide vaccination restored priming of ALK-specific CD8+ T cells, eradicated lung tumors in combination with ALK TKIs and prevented metastatic dissemination of tumors to the brain. The poor response of ALK+ NSCLC to ICIs was due to ineffective CD8+ T cell priming against ALK antigens and is circumvented through specific vaccination. Finally, we identified human ALK peptides displayed by HLA-A*02:01 and HLA-B*07:02 molecules. These peptides were immunogenic in HLA-transgenic mice and were recognized by CD8+ T cells from individuals with NSCLC, paving the way for the development of a clinical vaccine to treat ALK+ NSCLC.

Synergistically enhanced cancer immunotherapy by combining protamine-based nanovaccine with PD-L1 gene silence nanoparticle

Tumor vaccine has brought a new dawn for cancer immunotherapy, but disillusionary therapeutic outcomes have been achieved due to the inefficient in vivo vaccine delivery. Moreover, tumor cells customarily resort to various wily tricks to circumvent the recognition and sweeping of the immune system, the immune escape effect has badly aggravated the difficulty of cancer management. With respect to the foregoing, in this study, a promising combinational strategy which cooperated nanovaccine with immune escape inhibition was developed for synergistically enhancing the oncotherapy efficiency. On the one hand, natural polycationic macromolecule protamine (PRT) was utilized as the carrier to construct an antigen and adjuvant co-packaged nanovaccine for facilitating the ingestion in antigen-presenting cells, amplifying antigen cross-presentation and optimizing in vivo delivery. On the other hand, PD-L1 silence gene was selected and hitchhiked in a pH-responsive nanoparticle developed in our previous study. The therapeutic gene could be successfully delivered into the tumors to down-regulate PD-L1 expression and cripple tumor immune escape. The combination of nanovaccine with PD-L1 gene silence nanoparticle could synchronously stimulate antitumor immune responses and reduce immune escape, synergistically enhance the therapeutic efficiency. This study will furnish the prospective tactics for the research of cancer immunotherapy.

New developments in the mechanism and application of immune checkpoint inhibitors in cancer therapy (Review)

The use of immune checkpoint inhibitors (ICIs) has been demonstrated in the treatment of numerous types of cancer and ICIs have remained a key focus of cancer research. However, improvements in survival rates only occur in a subset of patients, due to the complexity of drug resistance. Therefore, further investigations are required to identify predictive biomarkers that distinguish responders and non‑responders. Combined therapeutics involving ICIs and other modalities demonstrate potential in overcoming resistance to ICIs; however, further preclinical and clinical trials are required. Concurrently, prompt recognition and intervention of immune‑related adverse events are crucial to optimize the use of ICIs in clinical treatment. The present study aimed to review the current literature surrounding the mechanisms and application of ICIs, with the aim of providing a theoretical basis for clinicians.

Intravenous heterologous prime-boost vaccination activates innate and adaptive immunity to promote tumor regression

Therapeutic neoantigen cancer vaccines have limited clinical efficacy to date. Here, we identify a heterologous prime-boost vaccination strategy using a self-assembling peptide nanoparticle TLR-7/8 agonist (SNP) vaccine prime and a chimp adenovirus (ChAdOx1) vaccine boost that elicits potent CD8 T cells and tumor regression. ChAdOx1 administered intravenously (i.v.) had 4-fold higher antigen-specific CD8 T cell responses than mice boosted by the intramuscular (i.m.) route. In the therapeutic MC38 tumor model, i.v. heterologous prime-boost vaccination enhances regression compared with ChAdOx1 alone. Remarkably, i.v. boosting with a ChAdOx1 vector encoding an irrelevant antigen also mediates tumor regression, which is dependent on type I IFN signaling. Single-cell RNA sequencing of the tumor myeloid compartment shows that i.v. ChAdOx1 reduces the frequency of immunosuppressive Chil3 monocytes and activates cross-presenting type 1 conventional dendritic cells (cDC1s). The dual effect of i.v. ChAdOx1 vaccination enhancing CD8 T cells and modulating the TME represents a translatable paradigm for enhancing anti-tumor immunity in humans.

Unlocking the potential of microfluidics in mass spectrometry-based immunopeptidomics for tumor antigen discovery

The identification of tumor-specific antigens (TSAs) is critical for developing effective cancer immunotherapies. Mass spectrometry (MS)-based immunopeptidomics has emerged as a powerful tool for identifying TSAs as physical molecules. However, current immunopeptidomics platforms face challenges in measuring low-abundance TSAs in a precise, sensitive, and reproducible manner from small needle-tissue biopsies (<1 mg). Inspired by recent advances in single-cell proteomics, microfluidics technology offers a promising solution to these limitations by providing improved isolation of human leukocyte antigen (HLA)-associated peptides with higher sensitivity. In this context, we highlight the challenges in sample preparation and the rationale for developing microfluidics technology in immunopeptidomics. Additionally, we provide an overview of promising microfluidic methods, including microchip pillar arrays, valved-based systems, droplet microfluidics, and digital microfluidics, and discuss the latest research on their application in MS-based immunopeptidomics and single-cell proteomics.

Innovative breakthroughs facilitated by single-cell multi-omics: manipulating natural killer cell functionality correlates with a novel subcategory of melanoma cells

Background

Melanoma is typically regarded as the most dangerous form of skin cancer. Although surgical removal of in situ lesions can be used to effectively treat metastatic disease, this condition is still difficult to cure. Melanoma cells are removed in great part due to the action of natural killer (NK) and T cells on the immune system. Still, not much is known about how the activity of NK cell-related pathways changes in melanoma tissue. Thus, we performed a single-cell multi-omics analysis on human melanoma cells in this study to explore the modulation of NK cell activity.

Materials and methods

Cells in which mitochondrial genes comprised > 20% of the total number of expressed genes were removed. Gene ontology (GO), gene set enrichment analysis (GSEA), gene set variation analysis (GSVA), and AUCcell analysis of differentially expressed genes (DEGs) in melanoma subtypes were performed. The CellChat package was used to predict cell-cell contact between NK cell and melanoma cell subtypes. Monocle program analyzed the pseudotime trajectories of melanoma cells. In addition, CytoTRACE was used to determine the recommended time order of melanoma cells. InferCNV was utilized to calculate the CNV level of melanoma cell subtypes. Python package pySCENIC was used to assess the enrichment of transcription factors and the activity of regulons in melanoma cell subtypes. Furthermore, the cell function experiment was used to confirm the function of TBX21 in both A375 and WM-115 melanoma cell lines.

Results

Following batch effect correction, 26,161 cells were separated into 28 clusters and designated as melanoma cells, neural cells, fibroblasts, endothelial cells, NK cells, CD4+ T cells, CD8+ T cells, B cells, plasma cells, monocytes and macrophages, and dendritic cells. A total of 10137 melanoma cells were further grouped into seven subtypes, i.e., C0 Melanoma BIRC7, C1 Melanoma CDH19, C2 Melanoma EDNRB, C3 Melanoma BIRC5, C4 Melanoma CORO1A, C5 Melanoma MAGEA4, and C6 Melanoma GJB2. The results of AUCell, GSEA, and GSVA suggested that C4 Melanoma CORO1A may be more sensitive to NK and T cells through positive regulation of NK and T cell-mediated immunity, while other subtypes of melanoma may be more resistant to NK cells. This suggests that the intratumor heterogeneity (ITH) of melanoma-induced activity and the difference in NK cell-mediated cytotoxicity may have caused NK cell defects. Transcription factor enrichment analysis indicated that TBX21 was the most important TF in C4 Melanoma CORO1A and was also associated with M1 modules. In vitro experiments further showed that TBX21 knockdown dramatically decreases melanoma cells' proliferation, invasion, and migration.

Conclusion

The differences in NK and T cell-mediated immunity and cytotoxicity between C4 Melanoma CORO1A and other melanoma cell subtypes may offer a new perspective on the ITH of melanoma-induced metastatic activity. In addition, the protective factors of skin melanoma, STAT1, IRF1, and FLI1, may modulate melanoma cell responses to NK or T cells.

Mechanisms of immune modulation in the tumor microenvironment and implications for targeted therapy

The efficacy of cancer therapies is limited to a great extent by immunosuppressive mechanisms within the tumor microenvironment (TME). Numerous immune escape mechanisms have been identified. These include not only processes associated with tumor, immune or stromal cells, but also humoral, metabolic, genetic and epigenetic factors within the TME. The identification of immune escape mechanisms has enabled the development of small molecules, nanomedicines, immune checkpoint inhibitors, adoptive cell and epigenetic therapies that can reprogram the TME and shift the host immune response towards promoting an antitumor effect. These approaches have translated into series of breakthroughs in cancer therapies, some of which have already been implemented in clinical practice. In the present article the authors provide an overview of some of the most important mechanisms of immunosuppression within the TME and the implications for targeted therapies against different cancers.

Mechanistic rationales for combining immunotherapy with radiotherapy

Immunotherapy consisted mainly of immune checkpoint inhibitors (ICIs) has led to significantly improved antitumor response. However, such response has been observed only in tumors possessing an overall responsive tumor immune micro-environment (TIME), in which the presence of functional tumor-infiltrating lymphocytes (TILs) is critical. Various mechanisms of immune escape from immunosurveillance exist, leading to different TIME phenotypes in correlation with primary or acquired resistance to ICIs. Radiotherapy has been shown to induce antitumor immunity not only in the irradiated primary tumor, but also at unirradiated distant sites of metastases. Such antitumor immunity is mainly elicited by radiation's stimulatory effects on antigenicity and adjuvanticity. Furthermore, it may be significantly augmented when irradiation is combined with immunotherapy, such as ICIs. Therefore, radiotherapy represents one potential therapeutic strategy to restore anti-tumor immunity in tumors presenting with an unresponsive TIME. In this review, the generation of anti-tumor immunity, its impairment, radiation's immunogenic properties, and the antitumor effects of combining radiation with immunotherapy will be comprehensively discussed.

Analysis on tumor immune microenvironment and construction of a prognosis model for immune-related skin cutaneous melanoma

OBJECTIVES

Malignant melanoma is a highly malignant and heterogeneous skin cancer. Although immunotherapy has improved survival rates, the inhibitory effect of tumor microenvironment has weakened its efficacy. To improve survival and treatment strategies, we need to develop immune-related prognostic models. Based on the analysis of the Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and Sequence Read Archive (SRA) database, this study aims to establish an immune-related prognosis prediction model, and to evaluate the tumor immune microenvironment by risk score to guide immunotherapy.

METHODS

Skin cutaneous melanoma (SKCM) transcriptome sequencing data and corresponding clinical information were obtained from the TCGA database, differentially expressed genes were analyzed, and prognostic models were developed using univariate Cox regression, the LASSO method, and stepwise regression. Differentially expressed genes in prognostic models confirmed by real-time reverse transcription PCR (real-time RT-PCR) and Western blotting. Survival analysis was performed by using the Kaplan-Meier method, and the effect of the model was evaluated by time-dependent receiver operating characteristic curve as well as multivariate Cox regression, and the prognostic model was validated by 2 GEO melanoma datasets. Furthermore, correlations between risk score and immune cell infiltration, Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data (ESTIMATE) score, immune checkpoint mRNA expression levels, tumor immune cycle, or tumor immune micro-environmental pathways were analyzed. Finally, we performed association analysis for risk score and the efficacy of immunotherapy.

RESULTS

We identified 4 genes that were differentially expressed in TCGA-SKCM datasets, which were mainly associated with the tumor immune microenvironment. A prognostic model was also established based on 4 genes. Among 4 genes, the mRNA and protein levels of killer cell lectin like receptor D1 (KLRD1), leukemia inhibitory factor (LIF), and cellular retinoic acid binding protein 2 (CRABP2) genes in melanoma tissues differed significantly from those in normal skin (all P<0.01). The prognostic model was a good predictor of prognosis for patients with SKCM. The patients with high-risk scores had significantly shorter overall survival than those with low-risk scores, and consistent results were achieved in the training cohort and multiple validation cohorts (P<0.001). The risk score was strongly associated with immune cell infiltration, ESTIMATE score, immune checkpoint mRNA expression levels, tumor immune cycle, and tumor immune microenvironmental pathways (P<0.001). The correlation analysis showed that patients with the high-risk scores were in an inhibitory immune microenvironment based on the prognostic model (P<0.01).

CONCLUSIONS

The immune-related SKCM prognostic model constructed in this study can effectively predict the prognosis of SKCM patients. Considering its close correlation to the tumor immune microenvironment, the model has some reference value for clinical immunotherapy of SKCM.

DNA based neoepitope vaccination induces tumor control in syngeneic mouse models

Recent findings have positioned tumor mutation-derived neoepitopes as attractive targets for cancer immunotherapy. Cancer vaccines that deliver neoepitopes via various vaccine formulations have demonstrated promising preliminary results in patients and animal models. In the presented work, we assessed the ability of plasmid DNA to confer neoepitope immunogenicity and anti-tumor effect in two murine syngeneic cancer models. We demonstrated that neoepitope DNA vaccination led to anti-tumor immunity in the CT26 and B16F10 tumor models, with the long-lasting presence of neoepitope-specific T-cell responses in blood, spleen, and tumors after immunization. We further observed that engagement of both the CD4+ and CD8+ T cell compartments was essential to hamper tumor growth. Additionally, combination therapy with immune checkpoint inhibition provided an additive effect, superior to either monotherapy. DNA vaccination offers a versatile platform that allows the encoding of multiple neoepitopes in a single formulation and is thus a feasible strategy for personalized immunotherapy via neoepitope vaccination.

Therapeutic strategies to enhance immune response induced by multiple myeloma cells

Multiple myeloma (MM)as a haematological malignancy is still incurable. In addition to the presence of somatic genetic mutations in myeloma patients, the presence of immunosuppressive microenvironment greatly affects the outcome of treatment. Although the discovery of immunotherapy makes it possible to break the risk of high toxicity and side effects of traditional chemotherapeutic drugs, there are still obstacles of ineffective treatment or disease recurrence. In this review, we discuss therapeutic strategies to further enhance the specific anti-tumor immune response by activating the immunogenicity of MM cells themselves. New ideas for future myeloma therapeutic approaches are provided.

IL-12 and IL-27 Promote CD39 Expression on CD8+ T Cells and Differentially Regulate the CD39+CD8+ T Cell Phenotype

Tumor-specific CD8+ T cells are critical components of antitumor immunity; however, factors that modulate their phenotype and function have not been completely elucidated. Cytokines IL-12 and IL-27 have recognized roles in promoting CD8+ T cells' effector function and mediated antitumor responses. Tumor-specific CD8+ tumor-infiltrating lymphocytes (TILs) can be identified based on surface expression of CD39, whereas bystander CD8+ TILs do not express this enzyme. It is currently unclear how and why tumor-specific CD8+ T cells uniquely express CD39. Given the important roles of IL-12 and IL-27 in promoting CD8+ T cell functionality, we investigated whether these cytokines could modulate CD39 expression on these cells. Using in vitro stimulation assays, we identified that murine splenic CD8+ T cells differentially upregulate CD39 in the presence of IL-12 and IL-27. Subsequently, we assessed the exhaustion profile of IL-12- and IL-27-induced CD39+CD8+ T cells. Despite the greatest frequency of exhausted CD39+CD8+ T cells after activation with IL-12, as demonstrated by the coexpression of TIM-3+PD-1+LAG-3+ and reduced degranulation capacity, these cells retained the ability to produce IFN-γ. IL-27-induced CD39+CD8+ T cells expressed PD-1 but did not exhibit a terminally exhausted phenotype. IL-27 was able to attenuate IL-12-mediated inhibitory receptor expression on CD39+CD8+ T cells but did not rescue degranulation ability. Using an immunogenic neuro-2a mouse model, inhibiting IL-12 activity reduced CD39+CD8+ TIL frequency compared with controls without changing the overall CD8+ TIL frequency. These results provide insight into immune regulators of CD39 expression on CD8+ T cells and further highlight the differential impact of CD39-inducing factors on the phenotype and effector functions of CD8+ T cells.

Lymphocyte networks are dynamic cellular communities in the immunoregulatory landscape of lung adenocarcinoma

Lymphocytes are key for immune surveillance of tumors, but our understanding of the spatial organization and physical interactions that facilitate lymphocyte anti-cancer functions is limited. We used multiplexed imaging, quantitative spatial analysis, and machine learning to create high-definition maps of lung tumors from a Kras/Trp53-mutant mouse model and human resections. Networks of interacting lymphocytes ("lymphonets") emerged as a distinctive feature of the anti-cancer immune response. Lymphonets nucleated from small T cell clusters and incorporated B cells with increasing size. CXCR3-mediated trafficking modulated lymphonet size and number, but T cell antigen expression directed intratumoral localization. Lymphonets preferentially harbored TCF1+ PD-1+ progenitor CD8+ T cells involved in responses to immune checkpoint blockade (ICB) therapy. Upon treatment of mice with ICB or an antigen-targeted vaccine, lymphonets retained progenitor and gained cytotoxic CD8+ T cell populations, likely via progenitor differentiation. These data show that lymphonets create a spatial environment supportive of CD8+ T cell anti-tumor responses.

Linked CD4 + /CD8 + T cell neoantigen vaccination overcomes immune checkpoint blockade resistance and enables tumor regression

Therapeutic benefit to immune checkpoint blockade (ICB) is currently limited to the subset of cancers thought to possess a sufficient tumor mutational burden (TMB) to allow for the spontaneous recognition of neoantigens (NeoAg) by autologous T cells. We explored whether the response of an aggressive low TMB squamous cell tumor to ICB could be improved through combination immunotherapy using functionally defined NeoAg as targets for endogenous CD4 + and CD8 + T cells. We found that, whereas vaccination with CD4 + or CD8 + NeoAg alone did not offer prophylactic or therapeutic immunity, vaccines containing NeoAg recognized by both subsets overcame ICB resistance and led to the eradication of large established tumors that contained a subset of PD-L1 + tumor-initiating cancer stem cells (tCSC), provided the relevant epitopes were physically linked. Therapeutic CD4 + /CD8 + T cell NeoAg vaccination produced a modified tumor microenvironment (TME) with increased numbers of NeoAg-specific CD8 + T cells existing in progenitor and intermediate exhausted states enabled by combination ICB-mediated intermolecular epitope spreading. The concepts explored herein should be exploited for the development of more potent personalized cancer vaccines that can expand the range of tumors treatable with ICB.

Smart drug delivery systems to overcome drug resistance in cancer immunotherapy

Cancer immunotherapy, a therapeutic approach that inhibits tumors by activating or strengthening anti-tumor immunity, is currently an important clinical strategy for cancer treatment; however, tumors can develop drug resistance to immune surveillance, resulting in poor response rates and low therapeutic efficacy. In addition, changes in genes and signaling pathways in tumor cells prevent susceptibility to immunotherapeutic agents. Furthermore, tumors create an immunosuppressive microenvironment via immunosuppressive cells and secrete molecules that hinder immune cell and immune modulator infiltration or induce immune cell malfunction. To address these challenges, smart drug delivery systems (SDDSs) have been developed to overcome tumor cell resistance to immunomodulators, restore or boost immune cell activity, and magnify immune responses. To combat resistance to small molecules and monoclonal antibodies, SDDSs are used to co-deliver numerous therapeutic agents to tumor cells or immunosuppressive cells, thus increasing the drug concentration at the target site and improving efficacy. Herein, we discuss how SDDSs overcome drug resistance during cancer immunotherapy, with a focus on recent SDDS advances in thwarting drug resistance in immunotherapy by combining immunogenic cell death with immunotherapy and reversing the tumor immunosuppressive microenvironment. SDDSs that modulate the interferon signaling pathway and improve the efficacy of cell therapies are also presented. Finally, we discuss potential future SDDS perspectives in overcoming drug resistance in cancer immunotherapy. We believe that this review will contribute to the rational design of SDDSs and development of novel techniques to overcome immunotherapy resistance.

Reprogramming of Tumor-reactive Tumor-infiltrating Lymphocytes to Human-induced Pluripotent Stem Cells

Tumor-infiltrating lymphocytes (TIL) that can recognize and kill tumor cells have curative potential in subsets of patients treated with adoptive cell transfer (ACT). However, lack of TIL therapeutic efficacy in many patients may be due in large part to a paucity of tumor-reactive T cells in TIL and the exhausted and terminally differentiated status of those tumor-reactive T cells. We sought to reprogram exhausted TIL that possess T-cell receptors (TCR) specific for tumor antigens into induced pluripotent stem cells (iPSC) to rejuvenate them for more potent ACT. We first attempted to reprogram tumor neoantigen-specific TIL by αCD3 Ab prestimulation which resulted in failure of establishing tumor-reactive TIL-iPSCs, instead, T cell-derived iPSCs from bystander T cells were established. To selectively activate and enrich tumor-reactive T cells from the heterogenous TIL population, CD8⁺ PD-1⁺ 4-1BB⁺ TIL population were isolated after coculture with autologous tumor cells, followed by direct reprogramming into iPSCs. TCR sequencing analysis of the resulting iPSC clones revealed that reprogrammed TIL-iPSCs encoded TCRs that were identical to the pre-identified tumor-reactive TCRs found in minimally cultured TIL. Moreover, reprogrammed TIL-iPSCs contained rare tumor antigen-specific TCRs, which were not detectable by TCR sequencing of the starting cell population. Thus, reprogramming of PD-1⁺ 4-1BB⁺ TIL after coculture with autologous tumor cells selectively generates tumor antigen-specific TIL-iPSCs, and is a distinctive method to enrich and identify tumor antigen-specific TCRs of low frequency from TIL.

SIGNIFICANCE

Reprogramming of TIL into iPSC holds great promise for the future treatment of cancer due to their rejuvenated nature and the retention of tumor-specific TCRs. One limitation is the lack of selective and efficient methods for reprogramming tumor-specific T cells from polyclonal TIL. Here we addressed this limitation and present a method to efficiently reprogram TIL into iPSC colonies carrying diverse tumor antigen reactive TCR recombination.