The recent advances of PD-1 and PD-L1 checkpoint signaling inhibition for breast cancer immunotherapy

miRNA-105-5p regulates the histone deacetylase HDAC2 through FOXG1 to affect the malignant biological behavior of triple-negative breast cancer cells

BACKGROUND

Triple-negative breast cancer (TNBC) is a specific subtype of breast cancer (BC). Some potential molecular targets have been identified, and miR-105-5p was found to be abnormally expressed in TNBC tissues.

OBJECTIVE

The objective of this study was to probe the effect of miR-105-5p on TNBC via FOXG1/HDAC2-mediated acetylation.

METHODS

An animal model of TNBC was established by injecting BC cells into the axillary area of nude mice. The levels of miR-105-5p, FOXG1, HDAC2, Bcl-2, Bax, and Ki67 were detected via RT‒qPCR, Western blotting and immunohistochemistry. Flow cytometry, CCK-8, Transwell and colony formation assays were used to measure apoptosis, proliferation and migration, respectively. Total histone acetylation levels were measured by ELISA. The binding of FOXG1 to HDAC2 was detected by co-immunoprecipitation. The binding relationship between miR-105-5p and FOXG1 was verified using a dual-luciferase reporter gene assay.

RESULTS

In this study, miR-105-5p and HDAC2 were highly expressed in the MDA-MB-231 and BT-549 BC cell lines, whereas FOXG1 was expressed at low levels. The inhibition of miR-105-5p inhibited the proliferation and migration of MDA-MB-231 and BT-549 cells and promoted their apoptosis. Bioinformatics analysis revealed that miR-105-5p and FOXG1 had a negative targeting regulatory relationship. FOXG1 overexpression had a similar effect on cancer cells as the inhibition of miR-105-5p. Moreover, experiments revealed that FOXG1 and HDAC2 could bind to each other and that HDAC2 overexpression or treatment with the histone acetyltransferase inhibitor Garcinol weakened the effect of FOXG1 overexpression. In addition, FOXG1 knockdown inhibited the effect of the miR-105-5p inhibitor, while Garcinol treatment further enhanced the effect of FOXG1 knockdown, inhibited histone acetylation, promoted the proliferation and migration of cancer cells, and inhibited apoptosis. Moreover, the in vivo results confirmed the in vitro results.

CONCLUSION

miR-105-5p promotes HDAC2 expression by reducing FOXG1, inhibits histone acetylation, and aggravates the malignant biological behavior of TNBC cells.

High Entropy 2D Layered Double Hydroxide Nanosheet Toward Cascaded Nanozyme-Initiated Chemodynamic and Immune Synergistic Therapy

High-entropy nanomaterials (HEMs) are a hot topic in the fields of energy and catalysis. However, in terms of promising biomedical applications, potential therapeutic studies involving HEMs are unprecedented. Herein, we demonstrated high entropy two-dimensional layered double hydroxide (HE-LDH) nanoplatforms with versatile physicochemical advantages that reprogram the tumor microenvironment (TME) and provide antitumor treatment via cascaded nanoenzyme-initiated chemodynamic and immune synergistic therapy. In response to the TME, the multifunctional HE-LDHs sequentially release metal ions, such as Co2+, Fe3+, and Cu2+, exhibiting exquisite superoxide dismutase (SOD), peroxidase (POD), and glutathione peroxidase (GPX) activities. The multiple enzymatic activities convert specific tumor metabolites into a continuous supply of cytotoxic reactive oxygen species (ROS) to relieve hypoxia under a TME. Thus, HE-LDHs facilitate robust nanozyme-initiated chemodynamic therapy (NCDT), achieving high therapeutic efficacy without obvious side effects. In addition, the release of Zn2+ from the HE-LDH matrix triggers the cyclic GMP-AMP synthase/stimulator of interferon gene (cGAS/STING) signaling pathway, boosting the innate immunotherapeutic efficacy. The intratumoral applications of the nanocomposite in tumor-bearing mice models indicate that HE-LDH-mediated NCDT and immune synergistic therapy effectively upregulated the expression of relevant antitumor cytokines and induced cytotoxic T lymphocyte infiltration, showing superior efficacy in inhibiting tumor growth. Therefore, this work opens a new research direction toward synchronized NCDT and immunotherapy of tumors using HEMs for advanced healthcare.

An updated review summarizing the anticancer potential of flavonoids via targeting NF-kB pathway

Nuclear factor-κB (NF-κB) cell signaling pathway is essential for the progression and development of numerous human disorders, including cancer. NF-κB signaling pathway regulates a wide range of physiological processes, such as cell survival, growth, and migration. Deregulated NF-kB signaling resulted in unregulated cell proliferation, viability, movement, and invasion, thus promoting tumor development. Recent findings have increasingly shown that plant derived phytochemicals that inhibit NF-κB signaling have the potential to be employed in cancer therapeutics. Flavonoids are a group of polyphenolic natural compounds present in various plants and their fruits, vegetables, and leaves. These compounds have numerous medicinal properties owing to their antioxidant, anti-inflammatory, antiviral, and antitumor characteristics. The main mechanism by which these flavonoids exhibit their anticancer potential is via potent antioxidative and immunomodulatory actions. Current research reports have demonstrated that these flavonoids exhibited their anticancer effects via suppressing the NF-κB signaling. Based on these facts, we have comprehensively outlined the cancer promoting role of NF-κB pathway in various processes including tumor progression, drug resistance, angiogenesis and metastasis. In addition to these, we also summarize the anticancer potential of flavonoids by specifically targeting the NF-κB pathway in various types of cancers.

Immune Checkpoints in B Cells: Unlocking New Potentials in Cancer Treatment

B cells are crucial component of humoral immunity, and their role in the tumor immune microenvironment (TME) has garnered significant attention in recent years. These cells hold great potential and application prospects in the field of tumor immunotherapy. Research has demonstrated that the TME can remodel various B cell functions, including proliferation, differentiation, antigen presentation, and antibody production, thereby invalidating the anti-tumor effects of B cells. Concurrently, numerous immune checkpoints (ICs) on the surface of B cells are upregulated. Aberrant B-cell IC signals not only impair the function of B cells themselves, but also modulate the tumor-killing effects of other immune cells, ultimately fostering an immunosuppressive TME and facilitating tumor immune escape. Blocking ICs on B cells is beneficial for reversing the immunosuppressive TME and restoring anti-tumor immune responses. In this paper, the intricate connection between B-cell ICs and the TME is delved into, emphasizing the critical role of targeting B-cell ICs in anti-tumor immunity, which may provide valuable insights for the future development of tumor immunotherapy based on B cells.

Identification and validation of a prognostic model based on immune-related genes in ovarian carcinoma

Background

A novel valuable prognostic model has been developed on the basis of immune-related genes (IRGs), which could be used to estimate overall survival (OS) in ovarian cancer (OC) patients in The Cancer Genome Atlas (TCGA) dataset and the International Cancer Genome Consortium (ICGC) dataset.

Methods

This prognostic model was engineered by employing LASSO regression in training cohort (TCGA dataset). The corresponding growth predictive values of this model for individualized survival was evaluated using survival analysis, receiver operating characteristic curve (ROC curve), and risk curve analysis. Combined with clinical characteristics, a model risk score nomogram for OS was well built. Thereafter, depended on the model risk score, patients were divided into high and low risk subgroups. The survival difference between these subgroups was measured using Kaplan-Meier survival method. In addition, correlations containing pathway enrichment, treatment, immune cell infiltration and the prognostic model were also analyzed. We established the ovarian cancer cell line W038 for this study and identified the performances of GBP1P1 knockdown on a series of activities including cellular proliferation, apoptosis, migration, and invasion of W038 cells in vitro.

Results

We constructed a 25-genes prognostic model (TNFAIP8L3, PI3, TMEM181, GBP1P1 (LOC400759), STX18, KIF26B, MRPS11, CACNA1C, PACSIN3, GMPR, MANF, PYGB, SNRPA1, ST7L, ZBP1, BMPR1B-DT, STAC2, LINC02585, LYPD6, NSG1, ACOT13, FAM120B, LEFTY1, SULT1A2, FZD3). The areas under the curves (AUC) of 1, 2 and 3 years were 0.806, 0.773 and 0.762, in the TCGA cohort, respectively. Besides, the effectiveness of the model was verified using ICGC testing data. Univariate and multivariate Cox regression analysis exposes the risk score as an independent prognosis predictor for OS both in the TCGA and ICGC cohort. In summary, we utilized comprehensive bioinformatics analysis to build an effective prognostic gene model for OC patients. These bioinformatic results suggested that GBP1P1 could act as a novel biomarker for OC. GBP1P1 knockdown substantially inhibited the proliferation, migration, and invasion of W038 cells in vitro, and increased the percentage of apoptotic W038 cells.

Conclusions

The analyses of genetic status of patients with 25-genes model might improve the ability to predict the prognosis of patients with OC and help to select patients suit able to therapies. Immune-related gene GBP1P1 might serve as prognostic biomarker for OC.

PD-L1 expression and tumor-infiltrating lymphocytes: Correlations and prognostic values in Chinese triple-negative breast cancer patients with different molecular subtyping

OBJECTIVE

To investigate the correlation between programmed death ligand-1 (PD-L1) expression and tumor-infiltrating lymphocytes (TILs) and evaluate the prognostic value of PD-L1 and TILs in Chinese triple-negative breast cancer (TNBC) patients with different molecular subtype METHODS: This retrospective study was conducted at 2020. Specifically, the pre-chemotherapy clinical data and non-stained tissue blocks of 465 TNBC patients visited the Fudan University Shanghai Cancer Center (FUSCC) between 2008 and 2014 were collected, with their blocks sliced and stained using PD-L1(SP142), and the outcome of subsequent chemotherapy obtained in 2020. The relapse-free survival (RFS) of the study population was calculated. The baseline PD-L1 expression status correlations with TILs and molecular subtypes were assessed using Spearman's rank correlation analysis and the Kruskal-Wallis test. Kaplan-Meier survival analyses were undertaken to evaluate the prognosis value of TILs and PD-L1 expression.

RESULTS

PD-L1 expression status on IC was moderately and positively correlated with stromal tumor-infiltrating lymphocytes (sTILs) (rs = 0.502, P <0.001) and iTILs (rs = 0.410, P < 0.001), respectively. PD-L1 expression status and TILs showed significant differences among molecular subtypes (P < 0.001), with the highest proportion of PD-L1+ and high TILs patients observed in the immunomodulatory (IM) subtype. TILs were significantly associated with RFS. Moreover, sTILs could act as an independent predictor of RFS (RR 0.953, 95 % CI 0.920 ∼ 0.987, P = 0.007), while PD-L1 expression status did not show the same prognostic significance.

CONCLUSIONS

The incorporation of pre-treatment TILs and PD-L1 expression status as valuable tools for optimizing patient selection for immunotherapy and managing the risks associated with chemotherapy in Chinese TNBC patients.

DATA AVAILABILITY

The data sets generated and analyzed during the current study are available from the corresponding author.

Targeting Neoantigens in Cancer: Possibilities and Opportunities in Breast Cancer

As one of the most prevalent forms of cancer worldwide, breast cancer has garnered significant attention within the clinical research setting. While traditional treatment employs a multidisciplinary approach including a variety of therapies such as chemotherapy, hormone therapy, and even surgery, researchers have since directed their attention to the budding role of neoantigens. Neoantigens are defined as tumor-specific antigens that result from a multitude of genetic alterations, the most prevalent of which is the single nucleotide variant. As a result of their foreign nature, neoantigens elicit immune responses upon presentation by Major Histocompatibility Complexes I and II followed by recognition by T cell receptors. Previously, researchers have been able to utilize these immunogenic properties and manufacture neoantigen-specific T-cells and neoantigen vaccines. Within the context of breast cancer, biomarkers such as tumor protein 53 (TP53), Survivin, Partner and Localizer of BRCA2 (PALB2), and protein tyrosine phosphatase receptor T (PTPRT) display exceeding potential to serve as neoantigens. However, despite their seemingly limitless potential, neoantigens must overcome various obstacles if they are to be fairly distributed to patients. For instance, a prolonged period between the identification of a neoantigen and the dispersal of treatment poses a serious risk within the context of breast cancer. Regardless of these current obstacles, it appears highly promising that future research into neoantigens will make an everlasting impact on the health outcomes within the realm of breast cancer. The purpose of this literature review is to comprehensively discuss the etiology of various forms of breast cancer and current treatment modalities followed by the significance of neoantigens in cancer therapeutics and their application to breast cancer. Further, we have discussed the limitations, future directions, and the role of transcriptomics in neoantigen identification and personalized medicine. The concepts discussed in the original and review articles were included in this review article.

Mathematical model predicts tumor control patterns induced by fast and slow cytotoxic T lymphocyte killing mechanisms

Immunotherapy has dramatically transformed the cancer treatment landscape largely due to the efficacy of immune checkpoint inhibitors (ICIs). Although ICIs have shown promising results for many patients, the low response rates in many cancers highlight the ongoing challenges in cancer treatment. Cytotoxic T lymphocytes (CTLs) execute their cell-killing function via two distinct mechanisms: a fast-acting, perforin-mediated process and a slower, Fas ligand (FasL)-driven pathway. Evidence also suggests that the preferred killing mechanism of CTLs depends on the antigenicity of tumor cells. To determine the critical factors affecting responses to ICIs, we construct an ordinary differential equation model describing in vivo tumor-immune dynamics in the presence of active or blocked PD-1/PD-L1 immune checkpoint. Specifically, we identify important aspects of the tumor-immune landscape that affect tumor size and composition in the short and long term. We also generate a virtual cohort of mice with diverse tumor and immune attributes to simulate the outcomes of immune checkpoint blockade in a heterogeneous population. By identifying key tumor and immune characteristics associated with tumor elimination, dormancy, and escape, we predict which fraction of a population potentially responds well to ICIs and ways to enhance therapeutic outcomes with combination therapy.

Potential of Dietary HDAC2i in Breast Cancer Patients Receiving PD-1/PD-L1 Inhibitors

Breast cancer (BC) is a lethal malignancy with high morbidity and mortality but lacks effective treatments thus far. Despite the introduction of immune checkpoint inhibitors (ICIs) (including PD-1/PD-L1 inhibitors), durable and optimal clinical benefits still remain elusive for a considerable number of BC patients. To break through such a dilemma, novel ICI-based combination therapy has been explored for enhancing the therapeutic effect. Recent evidence has just pointed out that the HDAC2 inhibitor (HDAC2i), which has been proven to exhibit an anti-cancer effect, can act as a sensitizer for ICIs therapy. Simultaneously, dietary intervention, as a crucial supportive therapy, has been reported to provide ingredients containing HDAC2 inhibitory activity. Thus, the novel integration of dietary intervention with ICIs therapy may offer promising possibilities for improving treatment outcomes. In this study, we first conducted the differential expression and prognostic analyses of HDAC2 and BC patients using the GENT2 and Kaplan-Meier plotter platform. Then, we summarized the potential diet candidates for such an integrated therapeutic strategy. This article not only provides a whole new therapeutic strategy for an HDAC2i-containing diet combined with PD-1/PD-L1 inhibitors for BC treatment, but also aims to ignite enthusiasm for exploring this field.

Glycolytic enzyme HK2 promotes PD-L1 expression and breast cancer cell immune evasion

Immune therapies targeting the PD-1/PD-L1 pathway have been employed in the treatment of breast cancer, which requires aerobic glycolysis to sustain breast cancer cells growth. However, whether PD-L1 expression is regulated by glycolysis in breast cancer cells remains to be further elucidated. Here, we demonstrate that glycolytic enzyme hexokinase 2 (HK2) plays a crucial role in upregulating PD-L1 expression. Under high glucose conditions, HK2 acts as a protein kinase and phosphorylates IκBα at T291 in breast cancer cells, leading to the rapid degradation of IκBα and activation of NF-κB, which enters the nucleus and promotes PD-L1 expression. Immunohistochemistry staining of human breast cancer specimens and bioinformatics analyses reveals a positive correlation between HK2 and PD-L1 expression levels, which are inversely correlated with immune cell infiltration and survival time of breast cancer patients. These findings uncover the intrinsic and instrumental connection between aerobic glycolysis and PD-L1 expression-mediated tumor cell immune evasion and underscore the potential to target the protein kinase activity of HK2 for breast cancer treatment.

Overexpression of PKMYT1 associated with poor prognosis and immune infiltration may serve as a target in triple-negative breast cancer

Breast cancer (BC) is one of the most common malignancies among women worldwide. It is necessary to search for improvement in diagnosis and treatment methods to improve the prognosis. Protein kinase, membrane associated tyrosine/threonine 1 (PKMYT1), a member of the Wee family of protein kinases, has been studied in some tumors except BC. This study has explored that PKMYT1 functional role by bioinformatics methods combined with local clinical samples and experiments. Comprehensive analysis showed that PKMYT1 expression was higher in BC tissues, especially in advanced patients than that in normal breast tissues. The expression of PKMYT1 was an independent determinant for BC patients' prognosis when combined with the clinical features. In addition, based on multi-omics analysis, we found that the PKMYT1 expression was closely relevant to several oncogenic or tumor suppressor gene variants. The analysis of single-cell sequencing indicated that PKMYT1 expression was upregulated in triple-negative breast cancer (TNBC), consistent with the results of bulk RNA-sequencing. High PKMYT1 expression was correlated with a poor prognosis. Functional enrichment analysis revealed that PKMYT1 expression was associated with cell cycle-related, DNA replication-related, and cancer-related pathways. Further research revealed that PKMYT1 expression was linked to immune cell infiltration in the tumor microenvironment. Additionally, loss-of-function experiments in vitro were performed to investigate the role of PKMYT1. TNBC cell lines' proliferation, migration, and invasion were inhibited when PKMYT1 expression was knock-down. Besides, the down-regulation of PKMYT1 induced apoptosis in vitro. As a result, PKMYT1 might be a biomarker for prognosis and a therapeutic target for TNBC.

Comprehensive analysis of nicotinamide metabolism-related signature for predicting prognosis and immunotherapy response in breast cancer

Background

Breast cancer (BC) is the most common malignancy among women. Nicotinamide (NAM) metabolism regulates the development of multiple tumors. Herein, we sought to develop a NAM metabolism-related signature (NMRS) to make predictions of survival, tumor microenvironment (TME) and treatment efficacy in BC patients.

Methods

Transcriptional profiles and clinical data from The Cancer Genome Atlas (TCGA) were analyzed. NAM metabolism-related genes (NMRGs) were retrieved from the Molecular Signatures Database. Consensus clustering was performed on the NMRGs and the differentially expressed genes between different clusters were identified. Univariate Cox, Lasso, and multivariate Cox regression analyses were sequentially conducted to develop the NAM metabolism-related signature (NMRS), which was then validated in the International Cancer Genome Consortium (ICGC) database and Gene Expression Omnibus (GEO) single-cell RNA-seq data. Further studies, such as gene set enrichment analysis (GSEA), ESTIMATE, CIBERSORT, SubMap, and Immunophenoscore (IPS) algorithm, cancer-immunity cycle (CIC), tumor mutation burden (TMB), and drug sensitivity were performed to assess the TME and treatment response.

Results

We identified a 6-gene NMRS that was significantly associated with BC prognosis as an independent indicator. We performed risk stratification according to the NMRS and the low-risk group showed preferable clinical outcomes (P < 0.001). A comprehensive nomogram was developed and showed excellent predictive value for prognosis. GSEA demonstrated that the low-risk group was predominantly enriched in immune-associated pathways, whereas the high-risk group was enriched in cancer-related pathways. The ESTIMATE and CIBERSORT algorithms revealed that the low-risk group had a higher abundance of anti-tumor immunocyte infiltration (P < 0.05). Results of Submap, IPS, CIC, TMB, and external immunotherapy cohort (iMvigor210) analyses showed that the low-risk group were indicative of better immunotherapy response (P < 0.05).

Conclusions

The novel signature offers a promising way to evaluate the prognosis and treatment efficacy in BC patients, which may facilitate clinical practice and management.

Advances in understanding cancer-associated neurogenesis and its implications on the neuroimmune axis in cancer

Nerves and immunologic mediators play pivotal roles in body homeostasis by interacting with each other through diverse mechanisms. The spread of nerves in the tumor microenvironment increases tumor cell proliferation and disease progression, and this correlates with poor patient outcomes. The effects of sympathetic and parasympathetic nerves on cancer regulation are being investigated. Recent findings demonstrate the possibility of developing therapeutic strategies that target the tumor microenvironment and its components such as immune cells, neurotransmitters, and extracellular vesicles. Therefore, examining and understanding the mechanisms and pathways associated with the sympathetic and parasympathetic nervous systems, neurotransmitters, cancer-derived mediators and their interactions with the immune system in the tumor microenvironment may lead to the development of new cancer treatments. This review discusses the effects of nerve cells, immune cells, and cancer cells have on each other that regulate neurogenesis, cancer progression, and dissemination.

Temsirolimus Enhances Anti-Cancer Immunity by Inducing Autophagy-Mediated Degradation of the Secretion of Small Extracellular Vesicle PD-L1

Simple Summary

Immune checkpoint blockade therapies (ICBT) have increasing importance in patient survival and prognosis because it enhances immune cell activation by inhibiting the binding of programmed death-ligand 1 (PD-L1) of tumor and programmed death-1 (PD-1) of T cells. However, tumor-derived small extracellular vesicle (sEV) PD-L1 trigger low reactivity in immunotherapy because it promotes tumor growth and metastasis and inhibits activation of immune cell. In this study, temsirolimus (TEM) which the Food and Drug Administration (FDA) approved as a targeted anti-cancer drug, inhibited tumor-derived sEV PD-L1 secretion by activating autophagy. In addition, TEM induced systemic anti-cancer immunity by increasing the number and activation of CD4⁺ and CD8⁺ T cells. Therefore, TEM showed that the anti-cancer effect was better in the breast cancer-bearing-immunocompetent mice than in the nude mice. In summary, we suggest that TEM can overcome sEV PD-L1-mediated immunosuppression in patients with cancer through activation of the immune system in the body by inhibiting tumor-derived sEV PD-L1.

Abstract

Tumor-derived small extracellular vesicle (sEV) programmed death-ligand 1 (PD-L1) contributes to the low reactivity of cells to immune checkpoint blockade therapy (ICBT), because sEV PD-L1 binds to programmed death 1 (PD-1) in immune cells. However, there are no commercially available anti-cancer drugs that activate immune cells by inhibiting tumor-derived sEV PD-L1 secretion and cellular PD-L1. Here, we aimed to investigate if temsirolimus (TEM) inhibits both sEV PD-L1 and cellular PD-L1 levels in MDA-MB-231 cells. In cancer cell autophagy activated by TEM, multivesicular bodies (MVBs) associated with the secretion of sEV are degraded through colocalization with autophagosomes or lysosomes. TEM promotes CD8⁺ T cell-mediated anti-cancer immunity in co-cultures of CD8⁺ T cells and tumor cells. Furthermore, the combination therapy of TEM and anti-PD-L1 antibodies enhanced anti-cancer immunity by increasing both the number and activity of CD4⁺ and CD8⁺ T cells in the tumor and draining lymph nodes (DLNs) of breast cancer-bearing immunocompetent mice. In contrast, the anti-cancer effect of the combination therapy with TEM and anti-PD-L1 antibodies was reversed by the injection of exogenous sEV PD-L1. These findings suggest that TEM, previously known as a targeted anti-cancer drug, can overcome the low reactivity of ICBT by inhibiting sEV PD-L1 and cellular PD-L1 levels.

Overexpressed VDAC1 in breast cancer as a novel prognostic biomarker and correlates with immune infiltrates

BACKGROUND

More and more evidence suggests that cancer is a mitochondrial metabolic disease recently and mitochondria dysfunction is critical to tumorigenesis. As a gatekeeper of mitochondria, the voltage-dependent anion channel 1 (VDAC1) is associated with the development of breast cancer (BC). However, its potential mechanism and clinical significance remain unclear; thus, in this research, we aimed to explore it.

METHODS

VDAC1 expression in BC tissues and normal tissues was obtained from The Cancer Genome Atlas (TCGA) and validated by datasets from the gene expression omnibus (GEO) database. Then, the relationships between VDAC1 expression and clinicopathological features were analyzed. Receiver operating characteristics (ROC) curves were used to identify the diagnostic value of VDAC1. The prognostic value was evaluated by Kaplan-Meier survival curves and Cox regression analysis. VDAC1 with its co-expression genes were subjected to enrichment analysis to explore potential mechanisms in BC and the protein-protein interaction (PPI) network was constructed. At last, the association between VDAC1 expression and infiltration levels of immune cell infiltration by various methods, as well as their corresponding markers, was analyzed. We also analyzed the correction between VDAC1 expression and eight immune checkpoint genes and the tumor immune dysfunction and exclusion (TIDE) scores of each BC sample in TCGA were calculated and the differences between high and low VDAC1 expression groups were analyzed.

RESULTS

VDAC1 expression was remarkably elevated in BC (p < 0.001), and high expression of VDAC1 was associated with the positive expression of ER (p = 0.004), PR (p = 0.033), and HER2 (p = 0.001). ROC analysis suggested that VDAC1 had diagnosed value in BC. The Kaplan-Meier analysis suggested that higher expression of VDAC1 was associated with shorter overall survival (OS), and further Cox regression analysis revealed that VDAC1 was an independent factor of unfavorable prognosis in BC patients. Enrichment analysis of VDAC1 and its co-expression suggested that VDAC1 was related to the regulation of mitochondrial energy metabolism and protein modification, and the HIF-1 singing pathway might be the potential mechanism in BC. Notably, we found that VDAC1 expression was infiltration levels of most types of immune cells, as well as the expression of marker genes of immune cells. The ICGs PDCD1, CTLA4, LAG3, SIGLEC15, and TIGIT were negatively corrected with VDAC1 expression in BC. TIDE scores between the low and high expression groups showed no difference.

CONCLUSION

Overexpressed VDAC1 in BC could be severed as a novel biomarker for diagnosis and VDAC1 was an independent factor for adverse prognosis prediction. Our study revealed that VDAC1 might inhibit tumor immunity and might be a novel therapeutic target in BC.

Novel immune subtypes identification of HER2-positive breast cancer based on immunogenomic landscape

HER2 positive BC is heterogeneous. But few studies discussed the classification of HER2-positive BC based on immune-related signatures. Using three publicly BC genomics datasets, we classified HER2 positive BC based on 33 immune-related signatures and used unsupervised machine learning methods to predict and perform the classification. We grouped three HER2-positive BC subtypes that we called Immune-High (IM-H), Immune-Medium (IM-M), and Immune-Low (IM-L), and manifested this categorization was predictable, duplicable and reliable by analyzing another dataset. Compared to other subtypes, IM-H had a higher immune cell infiltration level and stronger anti-tumor immune activities, as well as better clinical survival outcome. Besides these signatures, there were some cancer-related pathways which were hyperactivated in IM-H, including cytokine-cytokine receptor interactions, antigen processing and presentation pathways, natural killer cell-mediated cytotoxicity, Th1 and Th2 cell differentiation, chemokine signaling pathway, Th17 cell differentiation, B and T cell receptor signaling, NF-kappa B signaling, PD-L1 expression and PD-1 checkpoint pathway in cancer, TNF signaling, IL-17 signaling, NOD-like receptor signaling and Toll-like receptor signaling. By contrast, IM-L showed depressed immune-related signatures and enhanced activation of lycosylphosphatidylinositol-anchor biosynthesis and mismatch repair. Moreover, we discovered a gene co-expression network focused on eight transcription factor genes (EOMES, TBX21, GFI1, IRF4, POU2AF1, CIITA, FOXP3 and TOX) and one tumor suppress gene (PRF1), which were closely related with tumor immune. We identified three HER2-positive BC subtypes based on immune-related signatures, which had potential clinical implications and promoted the optimal stratification of HER2-positive BC responsive to immunotherapy.

Polymeric Systems for Cancer Immunotherapy: A Review

Immunotherapy holds enormous promise to create a new outlook of cancer therapy by eliminating tumors via activation of the immune system. In immunotherapy, polymeric systems play a significant role in improving antitumor efficacy and safety profile. Polymeric systems possess many favorable properties, including magnificent biocompatibility and biodegradability, structural and component diversity, easy and controllable fabrication, and high loading capacity for immune-related substances. These properties allow polymeric systems to perform multiple functions in immunotherapy, such as immune stimulants, modifying and activating T cells, delivery system for immune cargos, or as an artificial antigen-presenting cell. Among diverse immunotherapies, immune checkpoint inhibitors, chimeric antigen receptor (CAR) T cell, and oncolytic virus recently have been dramatically investigated for their remarkable success in clinical trials. In this report, we review the monotherapy status of immune checkpoint inhibitors, CAR-T cell, and oncolytic virus, and their current combination strategies with diverse polymeric systems.

Necroptosis-Associated lncRNA Prognostic Model and Clustering Analysis: Prognosis Prediction and Tumor-Infiltrating Lymphocytes in Breast Cancer

Necroptosis plays an important role in tumor genesis and progression. This study aims to identify necroptosis-related lncRNAs (NR-lncRNAs) in breast cancer (BC), and their prognostic value and relationship with the tumor immune environment (TIE) through bioinformatics. Methods. A total of 67 necroptosis-related genes (NRGs) are retrieved, and 13 prognostically relevant NR-lncRNAs are identified by co-expression and Univariate Cox regression analyses. After unsupervised clustering analysis, the patients are classified into three clusters, and their survival and immune infiltration are compared. Lasso regression analysis is conducted to construct a prognostic model using eight lncRNAs (USP30-AS1, AC097662.1, AC007686.3, AL133467.1, AP006284.1, NDUFA6-DT, LINC01871, AL135818.1). The model is validated by Kaplan-Meier survival analysis, Multivariate Cox regression analysis, and receiver-operating characteristic (ROC) curves. Correlation analysis is useful to identify associations between risk scores and clinicopathological features. GSEA, drug prediction, and immune checkpoints analysis are further used to differentiate between the risk groups. Results. The C3 cluster has longer overall survival (OS) and the highest immune score, indicative of an immunologically hot tumor that may be sensitive to immunotherapy. Furthermore, the OS is significantly higher in the low-risk group, even after dividing the patients into subgroups with different clinical characteristics. The area under the ROC curve (AUC) for 1-, 3-, and 5-year survival in the training set are 0.761, 0.734, and 0.664, respectively, which indicate the moderate predictive performance of the model. Conclusion. NR-lncRNAs can predict the prognosis of BC, distinguish between hot and cold tumors, and are potential predictive markers of the immunotherapy response.

Biomimetic GBM-targeted drug delivery system boosting ferroptosis for immunotherapy of orthotopic drug-resistant GBM

Background

Clinical studies have shown that the efficacy of programmed cell death receptor-1/programmed cell death ligand-1 (PD-1/PD-L1) inhibitors on glioblastoma (GBM) is much lower than what is expected because of the low immunogenicity of GBM. Ferroptosis of cancer cells can induce the maturation of dendritic cells (DC cells) and increase the activity of T cell. The activated T cells release IFN-γ, which subsequently induces the ferroptosis of cancer cells. Thus, the aim of this paper is to set up a new GBM-targeted drug delivery system (Fe₃O₄-siPD-L1@M_-BV2) to boost ferroptosis for immunotherapy of drug-resistant GBM.

Results

Fe₃O₄-siPD-L1@M_-BV2 significantly increased the accumulation of siPD-L1 and Fe²⁺ in orthotopic drug-resistant GBM tissue in mice. Fe₃O₄-siPD-L1@M_-BV2 markedly decreased the protein expression of PD-L1 and increased the ratio between effector T cells and regulatory T cells in orthotopic drug-resistant GBM tissue. Moreover, Fe₃O₄-siPD-L1@M_-BV2 induced ferroptosis of GBM cells and maturation of DC cell, and it also increased the ratio between M1-type microglia and M2-type microglia in orthotopic drug-resistant GBM tissue. Finally, the growth of orthotopic drug-resistant GBM in mice was significantly inhibited by Fe₃O₄-siPD-L1@M_-BV2.

Conclusion

The mutual cascade amplification effect between ferroptosis and immune reactivation induced by Fe₃O₄-siPD-L1@M_-BV2 significantly inhibited the growth of orthotopic drug-resistant GBM and prolonged the survival time of orthotopic drug-resistant GBM mice.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01360-6.

Soluble forms of PD-1/PD-L immune checkpoint receptor and ligand in blood serum of breast cancer patients: association with clinical pathologic factors and molecular type of the tumor

Results of enzyme-linked immunosorbent assay of the soluble forms of PD-1/PD-L immune checkpoint receptor and ligand (sPD-1 and sPD-L1) in pretreatment blood serum of 88 breast cancer patients at various disease stages aged 30-83 years are presented. The control group included 55 practically healthy women aged 19-82 years. Serum sPD-1 and sPD-L1 levels in breast cancer patients highly significantly (p<0.0001) differ from control and these changes are opposite: soluble receptor level is more than 6-fold decreased, while soluble ligand concentration - 5.5 fold increased. Both markers separately, as well as their ratio demonstrate very high sensitivity (94-100%) and specificity (95-100%) in relation to healthy control. No statistically significant associations of sPD-1 and sPD-L1 levels with clinical stage, individual TNM system criteria, tumor histological structure, grade, receptor status, and molecular type were established. In particular, no significant peculiarities of the markers' levels in triple negative breast cancer successfully treated with anti-PD-1/PD-L1 preparations were revealed. Long-term follow-up and dynamic studies of sPD-1 and sPD-L1serum levels in the course of treatment are required for evaluation of their independent from clinical and morphological factors prognostic significance and the possibility of application as low invasive tests for prediction and monitoring of corresponding targeted therapy efficiency.

Stimuli-Responsive Nanoparticles for Controlled Drug Delivery in Synergistic Cancer Immunotherapy

Cancer immunotherapy has achieved promising clinical progress over the recent years for its potential to treat metastatic tumors and inhibit their recurrences effectively. However, low patient response rates and dose-limiting toxicity remain as major dilemmas for immunotherapy. Stimuli-responsive nanoparticles (srNPs) combined with immunotherapy offer the possibility to amplify anti-tumor immune responses, where the weak acidity, high concentration of glutathione, overexpressions of enzymes, and reactive oxygen species, and external stimuli in tumors act as triggers for controlled drug release. This review highlights the design of srNPs based on tumor microenvironment and/or external stimuli to combine with different anti-tumor drugs, especially the immunoregulatory agents, which eventually realize synergistic immunotherapy of malignant primary or metastatic tumors and acquire a long-term immune memory to prevent tumor recurrence. The authors hope that this review can provide theoretical guidance for the construction and clinical transformation of smart srNPs for controlled drug delivery in synergistic cancer immunotherapy.

Synergistic antitumor efficacy of PD-1-conjugated PTX- and ZSQ-loaded nanoliposomes against multidrug-resistant liver cancers

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide with poor chemotherapeutic efficiency due to multidrug resistance (MDR); it is very important to develop a targeted nanocarrier for the treatment of HCC. In this study, a programmed death ligand 1 (PD-L1)-conjugated nanoliposome was constructed for co-delivery of paclitaxel (PTX) and P-glycoprotein (P-gp) inhibitor zosuquidar (ZSQ) to overcome MDR in human HCC cells and tumors in vivo. Transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA) were used to examine the nanoparticles morphology and size; PD-1-conjugated PTX and ZSQ-loaded nanoliposomes (PD-PZLP) revealed a spherical shape with a size of 139.5 ± 10.7 nm. Then, the physicochemical properties, as well as the drug loading capacity, release profile, cellular uptake, and cytotoxicity of the dual drug-encapsulated nanoliposomes were characterized. PD-PZLP displayed a high drug loading capacity of 20 ~ 30% for both PTX and ZSQ; the drug release of PTX and ZSQ in pH 5.0 was significantly faster than in pH 7.4. Cellular uptake study demonstrated PD-PZLP had higher internalization efficiency than non-targeted PZLP. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and reactive oxygen species (ROS) analysis demonstrated that PD-PZLP triggered an excessive ROS reaction and cell apoptosis compared with that of free PTX or ZSQ, which was also consistent with the cell antiproliferative effects in MTT assay. Furthermore, PD-PZLP could enhance synergistic antitumor effects on 7721/ADM xenograft tumor model, which also significantly alleviated hepatotoxicity as evident from the decreased aspartate transaminase (AST) and alanine transaminase (ALT) levels. Overall, PD-PZLP exhibited high loading capacity, significant synergistic effects, promising antitumor efficacy, and the lowest toxicity, which provide a promising strategy to overcome MDR in HCC.

Programmed Death-Ligand 1 Expression in Breast Cancer Patients: Clinicopathological Associations from a Single-Institution Study

PURPOSE

Tumor expression of programmed death-ligand 1 (PD-L1) is associated with evasion of immune response in several types of malignancies and such expression may render patients eligible for PD-L1 inhibitors. The use of immune checkpoint blockade therapy has been recently approved for the treatment of breast cancer. However, PD-L1 expression data are lacking among Jordanian breast cancer patients. In this study, the tumor PD-L1 expression was characterized in breast cancer patients to assess their eligibility for immune checkpoint blockade therapy. The study also aimed to explore the association between tumoral PD-L1 expression and the clinicopathologic characteristics and the prognostic factors in patients with breast cancer.

PATIENTS AND METHODS

Tissue samples were available from 153 female patients with primary invasive breast cancer. Immunohistochemistry was performed on paraffin-embedded tumor sections that were stained with a PD-L1 antibody. Expression of tumor PD-L1 was correlated with demographics, clinicopathologic characteristics, and prognosis.

RESULTS

The mean age at diagnosis was 54.2±12.8 years (median 52, interquartile range 45-65). The percentage of PD-L1-positive tumors was 26.1%. PD-L1 expression on tumor cells significantly and positively correlated with tumor size (rho=0.174, p=0.032). PD-L1 positivity was significantly associated with the grade of carcinoma (p=0.001), HER2-positivity (p=0.015), and lymphovascular invasion (p=0.036). PD-L1 intensity was significantly associated with tumor stage (p=0.046). No significant associations were observed for the PD-L1 expression status or intensity with patient menopausal status, hormone receptor expression, and molecular subtypes. PD-L1 expression significantly correlated with a worse prognosis of breast cancer patients at the time of diagnosis (rho=0.230, p=0.005).

CONCLUSION

Tumor PD-L1 expression was associated with advanced clinicopathologic features and worse prognosis in this cohort of Jordanian breast cancer patients. Future studies are needed to better understand the impact of PD-L1 blockade therapy on treatment outcomes in eligible breast cancer patients in Jordan.

Histone deacetylase 2 knockout suppresses immune escape of triple-negative breast cancer cells via downregulating PD-L1 expression

The PD-L1 overexpression is an important event of immune escape and metastasis in triple-negative breast cancer (TNBC), but the molecular mechanism remains to be determined. Interferon gamma (IFNγ) represents a major driving force behind PD-L1 expression in tumor microenvironment, and histone deacetylase 2 (HDAC2) is required for IFN signaling. Here, we investigated the regulation of HDAC2 on the IFNγ-induced PD-L1 expression in TNBC cells. We found the HDAC2 and PD-L1 expression in TNBC was significantly higher than that in non-TNBC, and HDAC2 was positively correlated with PD-L1 expression. HDAC2 promoted PD-L1 induction by upregulating the phosphorylation of JAK1, JAK2, and STAT1, as well as the translocation of STAT1 to the nucleus and the recruitment of STAT1 to the PD-L1 promoter. Meanwhile, HDAC2 was recruited to the PD-L1 promoter by STAT1, and HDAC2 knockout compromised IFNγ-induced upregulation of H3K27, H3K9 acetylation, and the BRD4 recruitment in PD-L1 promoter. In addition, significant inhibition of proliferation, colony formation, migration, and cell cycle of TNBC cells were observed following knockout of HDAC2 in vitro. Furthermore, HDAC2 knockout reduced IFNγ-induced PD-L1 expression, lymphocyte infiltration, and retarded tumor growth and metastasis in the breast cancer mouse models. This study may provide evidence that HDAC2 promotes IFNγ-induced PD-L1 expression, suggesting a way for enhanced antitumor immunity when targeting the HDAC2 in TNBC.