Lymph node targeting strategy using a hydrogel sustained-release system to load effector memory T cells improves the anti-tumor efficacy of anti-PD-1

Communication between tumors and lymph nodes carries substantial significance for antitumor immunotherapy. Remodeling the immune microenvironment of tumor-draining lymph nodes (TdLN) plays a key role in enhancing the anti-tumor ability of immunotherapy. In this study, we constructed a biomimetic artificial lymph node structure composed of F127 hydrogel loading effector memory T (TEM) cells and PD-1 inhibitors (aPD-1). The biomimetic lymph nodes facilitate the delivery of TEM cells and aPD-1 to the TdLN and the tumor immune microenvironment, thus realizing effective and sustained anti-tumor immunotherapy. Exploiting their unique gel-forming and degradation properties, the cold tumors were speedily transformed into hot tumors via TEM cell supplementation. Meanwhile, the efficacy of aPD-1 was markedly elevated compared with conventional drug delivery methods. Our finding suggested that the development of F127@TEM@aPD-1 holds promising potential as a future novel clinical drug delivery technique. STATEMENT OF SIGNIFICANCE: F127@TEM@aPD-1 show unique advantages in cancer treatment. When injected subcutaneously, F127@TEM@aPD-1 can continuously supplement TEM cells and aPD-1 to tumor draining lymph nodes (TdLN) and the tumor microenvironment, not only improving the efficacy of ICB therapy through slow release, but also exhibiting dual regulatory effects on the tumor and TdLN.

Biomimetic MDSCs membrane coated black phosphorus nanosheets system for photothermal therapy/photodynamic therapy synergized chemotherapy of cancer

Photothermal therapy is favored by cancer researchers due to its advantages such as controllable initiation, direct killing and immune promotion. However, the low enrichment efficiency of photosensitizer in tumor site and the limited effect of single use limits the further development of photothermal therapy. Herein, a photo-responsive multifunctional nanosystem was designed for cancer therapy, in which myeloid-derived suppressor cell (MDSC) membrane vesicle encapsulated decitabine-loaded black phosphorous (BP) nanosheets (BP@ Decitabine @MDSCs, named BDM). The BDM demonstrated excellent biosafety and biochemical characteristics, providing a suitable microenvironment for cancer cell killing. First, the BDM achieves the ability to be highly enriched at tumor sites by inheriting the ability of MDSCs to actively target tumor microenvironment. And then, BP nanosheets achieves hyperthermia and induces mitochondrial damage by its photothermal and photodynamic properties, which enhancing anti-tumor immunity mediated by immunogenic cell death (ICD). Meanwhile, intra-tumoral release of decitabine induced G2/M cell cycle arrest, further promoting tumor cell apoptosis. In vivo, the BMD showed significant inhibition of tumor growth with down-regulation of PCNA expression and increased expression of high mobility group B1 (HMGB1), calreticulin (CRT) and caspase 3. Flow cytometry revealed significantly decreased infiltration of MDSCs and M2-macrophages along with an increased proportion of CD4+, CD8+ T cells as well as CD103+ DCs, suggesting a potentiated anti-tumor immune response. In summary, BDM realizes photothermal therapy/photodynamic therapy synergized chemotherapy for cancer.

Manganese drives ferroptosis of cancer cells via YAP/TAZ phase separation activated ACSL4 in OSCC

OBJECTIVE

Ferroptosis has been defined as a novel form of regulated cell death characterized by iron-dependent lipid peroxidation. Manganese has been used to induce ferroptosis in cancer cells recently. This study aims to investigate whether manganese can induce ferroptosis in oral squamous cell carcinoma (OSCC) and the underlying biological mechanisms.

MATERIALS AND METHODS

Cancer cells with or without manganese treatment were analyzed by RNA-sequencing to identify ferroptosis-related genes. Next, the activation of YAP/TAZ/ACSL4-ferroptosis signaling pathway was detected. Bioinformatic analysis and immunofluorescence assay were used to explore the phase separation of YAP/TAZ. Finally, specimens of OSCC patients were applied to analyze the clinical significance of YAP/TAZ/ACSL4.

RESULTS

RNA-sequencing analysis showed the ferroptosis-related genes and YAP/TAZ were upregulated after manganese treatment. The results of immunofluorescence, ELISA, western blotting, etc. further confirmed that manganese-induced ferroptosis depends on YAP/TAZ/ACSL4 signaling pathway. Moreover, the activation of ACSL4 was achieved by YAP/TAZ phase separation. The survival analysis in OSCC specimen suggested that the higher level of YAP/TAZ-ACSL4 axis expression indicates longer survival.

CONCLUSIONS

Manganese induces YAP/TAZ phase separation and subsequent ACSL4 activation via YAP/TAZ nuclear translocation, which facilitates ferroptosis of OSCC. Then YAP/TAZ-ACSL4 axis can be used as a potential prognostic predictor of OSCC patients.

CD24 blockade promotes anti-tumor immunity in oral squamous cell carcinoma

OBJECTIVES

Our study elucidates the prognostic role of cluster of differentiation (CD) 24 expression in oral squamous cell carcinoma (OSCC) and determines whether targeting CD24 enhances the anti-tumor immune response by inhibiting tumor-associated macrophages (TAMs).

MATERIALS AND METHODS

The expression of CD24 and CD68 was analyzed immunohistochemically via tissue microarrays constructed using 56 cohorts of patients with OSCC and 20 control specimens. Further, CD24 was inhibited in an allograft squamous cell carcinoma (SCC) related mouse model with CD24mAb to determine the tumor volume and weight. Changes in immune cells such as TAMs and T cells in the tumor microenvironment (TME) were analyzed by Flow cytometry. The expression of CD4, CD8, and Ki67 was analyzed via immunohistochemistry. The inhibition of CD24 was confirmed by Western blot and immunohistochemistry.

RESULTS

CD24 was overexpressed in OSCC. High expression of CD24 indicated poor survival in patients with OSCC (p = 0.0334). CD24 expression was significantly correlated with CD68 (p = 0.0424). The inhibition of CD24 delayed tumor growth in vivo. A decrease in TAMs number and an increase in T cell number were confirmed, while the ability of tumor proliferation was impaired.

CONCLUSION

Targeting CD24 could enhance anti-tumor immune response by inhibiting TAMs.

Microwave-responsive gadolinium metal-organic frameworks nanosystem for MRI-guided cancer thermotherapy and synergistic immunotherapy

The clinical application of cancer immunotherapy is unsatisfied due to low response rates and systemic immune-related adverse events. Microwave hyperthermia can be used as a synergistic immunotherapy to amplify the antitumor effect. Herein, we designed a Gd-based metal-organic framework (Gd-MOF) nanosystem for MRI-guided thermotherapy and synergistic immunotherapy, which featured high performance in drug loading and tumor tissue penetration. The PD-1 inhibitor (aPD-1) was initially loaded in the porous Gd-MOF (Gd/M) nanosystem. Then, the phase change material (PCM) and the cancer cell membrane were further sequentially modified on the surface of Gd/MP to obtain Gd-MOF@aPD-1@CM (Gd/MPC). When entering the tumor microenvironment (TME), Gd/MPC induces immunogenic death of tumor cells through microwave thermal responsiveness, improves tumor suppressive immune microenvironment and further enhances anti-tumor ability of T cells by releasing aPD-1. Meanwhile, Gd/MPC can be used for contrast-enhanced MRI. Transcriptomics data revealed that the downregulation of MSK2 in cancer cells leads to the downregulation of c-fos and c-jun, and ultimately leads to the apoptosis of cancer cells after treatment. In general, Gd/MPC nanosystem not only solves the problem of system side effect, but also achieves the controlled drug release via PCM, providing a promising theranostic nanoplatform for development of cancer combination immunotherapy.

3D-printed bioink loading with stem cells and cellular vesicles for periodontitis-derived bone defect repair

The suitable microenvironment of bone regeneration is critically important for periodontitis-derived bone defect repair. Three major challenges in achieving a robust osteogenic reaction are the exist of oral inflammation, pathogenic bacteria invasion and unaffluent seed cells. Herein, a customizable and multifunctional 3D-printing module was designed with glycidyl methacrylate (GMA) modified epsilon-poly-L-lysine (EPLGMA) loading periodontal ligament stem cells (PDLSCs) and myeloid-derived suppressive cells membrane vesicles (MDSCs-MV) bioink (EPLGMA/PDLSCs/MDSCs-MVs, abbreviated as EPM) for periodontitis-derived bone defect repair. The EPM showed excellent mechanical properties and physicochemical characteristics, providing a suitable microenvironment for bone regeneration.In vitro, EPMs presented effectively kill the periodontopathic bacteria depend on the natural antibacterial properties of the EPL. Meanwhile, MDSCs-MV was confirmed to inhibit T cells through CD73/CD39/adenosine signal pathway, exerting an anti-inflammatory role. Additionally, seed cells of PDLSCs provide an adequate supply for osteoblasts. Moreover, MDSCs-MV could significantly enhance the mineralizing capacity of PDLSCs-derived osteoblast. In the periodontal bone defect rat model, the results of micro-CT and histological staining demonstrated that the EPM scaffold similarly had an excellent anti-inflammatory and bone regeneration efficacyin vivo. This biomimetic and multifunctional 3D-printing bioink opens new avenues for periodontitis-derived bone defect repair and future clinical application.

The role of oral microbiota in cancer

Cancer remains a significant global challenge, with an estimated 47% increase in cancer patients from 2020 to 2040. Increasing research has identified microorganism as a risk factor for cancer development. The oral cavity, second only to the colon, harbors more than 700 bacterial species and serves as a crucial microbial habitat. Although numerous epidemiological studies have reported associations between oral microorganisms and major systemic tumors, the relationship between oral microorganisms and cancers remains largely unclear. Current research primarily focuses on respiratory and digestive system tumors due to their anatomical proximity to the oral cavity. The relevant mechanism research mainly involves 47% dominant oral microbial population that can be cultured in vitro. However, further exploration is necessary to elucidate the mechanisms underlying the association between oral microbiota and tumors. This review systematically summarizes the reported correlations between oral microbiota and common cancers while also outlining potential mechanisms that may guide biological tumor treatment.

Inhalation delivery of dexamethasone with iSEND nanoparticles attenuates the COVID-19 cytokine storm in mice and nonhuman primates

Dexamethasone (DEX) is the first drug to show life-saving efficacy in patients with severe coronavirus disease 2019 (COVID-19), while DEX is associated with serious adverse effects. Here, we report an inhaled, Self-immunoregulatory, Extracellular Nanovesicle-based Delivery (iSEND) system by engineering neutrophil nanovesicles with cholesterols to deliver DEX for enhanced treatment of COVID-19. Relying on surface chemokine and cytokine receptors, the iSEND showed improved targeting to macrophages and neutralized broad-spectrum cytokines. The nanoDEX, made by encapsulating DEX with the iSEND, efficiently promoted the anti-inflammation effect of DEX in an acute pneumonia mouse model and suppressed DEX-induced bone density reduction in an osteoporosis rat model. Relative to an intravenous administration of DEX at 0.1 milligram per kilogram, a 10-fold lower dose of nanoDEX administered by inhalation produced even better effects against lung inflammation and injury in severe acute respiratory syndrome coronavirus 2-challenged nonhuman primates. Our work presents a safe and robust inhalation delivery platform for COVID-19 and other respiratory diseases.

Ferroptosis promotes anti-tumor immune response by inducing immunogenic exposure in HNSCC

Accumulated evidence indicates that immune cell populations play pivotal roles in the process of tumor initiation, progression, recurrence, metastasis, and immune escape. Ferroptosis is a form of regulating cell death in the nexus between metabolism, redox biology, and human health. Ferroptosis is considered as a vital important event in HNSCC, but the underling mechanism of regulating immune cell populations remains poorly understood. Our tissue microarray study showed that patients with high expression of GPX4 were related to poor survival. Moreover, the expression of GPX4 has been negatively associated with immunogenic cell death-related protein calreticulin in HNSCC tissue cohort. Further, RSL3 was used to induce ferroptosis in HNSCC xenograft of C3H/He mouse. We found that the occurrence of ferroptosis had significantly reduced the number of myeloid-derived suppressor cells (MDSCs) and tumor-associated M2-like macrophages (M2 TAMs) in tumor microenvironment. Meanwhile, the tumor-infiltrating CD4⁺ and CD8⁺ T cells were increased. And the calreticulin and HMGB1 may be potential candidate proteins improving the immunosuppressive tumor microenvironment. Taken together, our project suggests that ferroptosis can promote anti-tumor immune response by reversing immunosuppressive microenvironment, indicating that ferroptosis inducer is a promising therapeutic strategy in HNSCC.

PFC@O2 Targets HIF-1α to Reverse the Immunosuppressive TME in OSCC

As a typical hallmark of solid tumors, hypoxia affects the effects of tumor radiotherapy, chemotherapy, and photodynamic therapy. Therefore, targeting the hypoxic tumor microenvironment (TME) is a promising treatment strategy for cancer therapy. Here, we prepared an Albumin Human Serum (HSA)-coated perfluorocarbon (PFC) carrying oxygen (PFC@O₂) to minimize OSCC hypoxia. The results showed that PFC@O₂ significantly downregulated the expression of HIF-1α and the number of M2-like macrophages in vitro. Furthermore, PFC@O₂ effectively inhibited the growth of oral squamous cell carcinoma (OSCC) and reduced the proportion of negative immunoregulatory cells, including myeloid-derived suppressor cells (MDSCs) and M2-like macrophages of TME in a 4-nitroquinoline N-oxide (4NQO)-induced mouse model. Conversely, the infiltration of CD4⁺ and CD8⁺ T cells was significantly increased in TME, suggesting that the anti-tumor immune response was enhanced. However, we also found that hypoxia-relative genes expression was positively correlated with CD68⁺/CD163⁺ TAMs in human tissue specimens. In summary, PFC@O₂ could effectively inhibit the progression of OSCC by alleviating hypoxia, which provides a practical basis for gas therapy and gas synergistic therapy for OSCC.

Advanced materials and technologies for oral diseases

Oral disease, as a class of diseases with very high morbidity, brings great physical and mental damage to people worldwide. The increasing burden and strain on individuals and society make oral diseases an urgent global health problem. Since the treatment of almost all oral diseases relies on materials, the rapid development of advanced materials and technologies has also promoted innovations in the treatment methods and strategies of oral diseases. In this review, we systematically summarized the application strategies in advanced materials and technologies for oral diseases according to the etiology of the diseases and the comparison of new and old materials. Finally, the challenges and directions of future development for advanced materials and technologies in the treatment of oral diseases were refined. This review will guide the fundamental research and clinical translation of oral diseases for practitioners of oral medicine.

Three novel MOFs constructed from 1,3,5-tris(1-imidazolyl)benzene and dicarboxylate ligands with selective adsorption for C2H2/C2H4 and C2H6/CH4

The urothermal reactions of Co(II)/Zn(II) salts with the diverse carboxylic acid and 1,3,5,-tris(1-imidazolyl)benzene(tib) ligands afforded three novel MOFs, namely, [Co₃(tib)₂(abdc)₂(ox)]₂·6H₂O (1), [Co₃O(tib)(abdc)₂(DMI)]·2DMI·2H₂O (2) and [Zn₃I₂(tib)₂(napdc)₂]·2DMI·2H₂O (3), (H₂abdc = 5-amino-1,3-benzenedicarboxylate, H₂napdc = 1,4-naphthalene dicarboxylic acid and DMI = 1,3-dimethyl-2-imidazolidinone). In compounds 1 and 2, the Co(II) atoms are connected by polycarboxylate ligands to form two-dimensional (2D) layers that are pillared by tib ligands leading to the formation of 3D porous frameworks. In compound 3, the Zn(II) atoms are linked by tib ligands to form one-dimensional ribbon-like chains which are further connected by polycarboxylate ligands, making a 3D framework possible. Compound 1 can selectively adsorb unsaturated hydrocarbon molecules (C₂H₂ and C₂H₄) and saturated hydrocarbon molecules (C₂H₆ and CH₄). Specifically, compound 1 has high IAST selectivity for acetylene and methane (0.50 : 0.50, v/v) at 273 K and 1 bar. DFT calculations reveal that the π-conjugated hexagonal carbon ring may be the primary adsorption site because there are π-π interactions between the unsaturated hydrocarbon molecules (C₂H₂ and C₂H₄) and the π-conjugated hexagonal carbon ring in the framework of compound 1.

Genetically Programmable Fusion Cellular Vesicles for Cancer Immunotherapy

Herein, we report that genetically programmable fusion cellular vesicles (Fus-CVs) displaying high-affinity SIRPα variants and PD-1 can activate potent antitumor immunity through both innate and adaptive immune effectors. Dual-blockade of CD47 and PD-L1 with Fus-CVs significantly increases the phagocytosis of cancer cells by macrophages, promotes antigen presentation, and activates antitumor T-cell immunity. Moreover, the bispecific targeting design of Fus-CVs ensures better targeting on tumor cells, but less on other cells, which reduces systemic side effects and enhances therapeutic efficacies. In malignant melanoma and mammary carcinoma models, we demonstrate that Fus-CVs significantly improve overall survival of model animals by inhibiting post-surgery tumor recurrence and metastasis. The Fus-CVs are suitable for protein display by genetic engineering. These advantages, integrated with other unique properties inherited from source cells, make Fus-CVs an attractive platform for multi-targeting immune checkpoint blockade therapy.

Genome-Wide Enhancer Analysis Reveals the Role of AP-1 Transcription Factor in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is one of the most common cancers in the world, but its epigenomic features have not been determined. Here, we studied the chromatin landscape of active enhancers of HNSCC head tumor tissues by performing H3K27ac and H3K4me1 ChIP-Seq with a Tgfbr1/Pten double conditional knockout HNSCC mouse model. We identified 1,248 gain variant enhancer loci (VELs) and 2,188 lost VELs, as well as 153 gain variant super enhancer loci (VSELs) and 234 lost VSELs. Potentially involved transcription factors were predicted with motif analysis, and we identified AP-1 as one of the critical oncogenic transcription factors in HNSCC and many other types of cancer. Combining transcriptomic and epigenomic data, our analysis also showed that AP-1 and histone modifications coordinately regulate target gene expression in HNSCC. In conclusion, our study provides important epigenomic information for enhancer studies in HNSCC and reveals new mechanism for AP-1 regulating HNSCC.

Hybrid cellular membrane nanovesicles amplify macrophage immune responses against cancer recurrence and metastasis

Effectively activating macrophages against cancer is promising but challenging. In particular, cancer cells express CD47, a 'don't eat me' signal that interacts with signal regulatory protein alpha (SIRPα) on macrophages to prevent phagocytosis. Also, cancer cells secrete stimulating factors, which polarize tumor-associated macrophages from an antitumor M1 phenotype to a tumorigenic M2 phenotype. Here, we report that hybrid cell membrane nanovesicles (known as hNVs) displaying SIRPα variants with significantly increased affinity to CD47 and containing M2-to-M1 repolarization signals can disable both mechanisms. The hNVs block CD47-SIRPα signaling axis while promoting M2-to-M1 repolarization within tumor microenvironment, significantly preventing both local recurrence and distant metastasis in malignant melanoma models. Furthermore, by loading a stimulator of interferon genes (STING) agonist, hNVs lead to potent tumor inhibition in a poorly immunogenic triple negative breast cancer model. hNVs are safe, stable, drug loadable, and suitable for genetic editing. These properties, combined with the capabilities inherited from source cells, make hNVs an attractive immunotherapy.

Molecular Targeting Nanoprobes with Non-Overlap Emission in the Second Near-Infrared Window for in Vivo Two-Color Colocalization of Immune Cells

Monitoring specific immune cells in vivo will provide significant information for improving the therapeutic effect of immunotherapy. Herein, the in vivo two-color fluorescence molecular imaging of an important immune cell, myeloid-derived suppressor cell (MDSC), was realized by using quantum dot (QD)-based nanoprobes with non-overlap emission in the second near-infrared window (NIR-II, 1000-1700 nm). NIR-IIa and NIR-IIb QDs were conjugated with two MDSC-specific antibodies, respectively, and targeted the in vivo MDSCs together. Due to the suppressed photon scattering and diminished autofluorescence in the NIR-II window, the distribution of MDSCs in different organs and tissues was clearly revealed in a non-invasive way by the colocalization of two-color fluorescence from nanoprobes. The high-resolution imaging further confirmed the exact distribution of MDSCs in tumor immune microenvironment (TIME). Our results demonstrated that NIR-II fluorescence nanoprobes with molecular targeting ability provided a powerful tool for monitoring the dynamic change of immune cell populations in TIME in vivo, thus guiding the choice of clinical medicine and evaluating the therapeutic effect.

Blockade of TIGIT/CD155 Signaling Reverses T-cell Exhaustion and Enhances Antitumor Capability in Head and Neck Squamous Cell Carcinoma

Immunosuppression is common in head and neck squamous cell carcinoma (HNSCC). In previous studies, the TIGIT/CD155 pathway was identified as an immune-checkpoint signaling pathway that contributes to the "exhaustion" state of infiltrating T cells. Here, we sought to explore the clinical significance of TIGIT/CD155 signaling in HNSCC and identify the therapeutic effect of the TIGIT/CD155 pathway in a transgenic mouse model. TIGIT was overexpressed on tumor-infiltrating CD8⁺ and CD4⁺ T cells in both HNSCC patients and mouse models, and was correlated with immune-checkpoint molecules (PD-1, TIM-3, and LAG-3). TIGIT was also expressed on murine regulatory T cells (Treg) and correlated with immune suppression. Using a human HNSCC tissue microarray, we found that CD155 was expressed in tumor and tumor-infiltrating stromal cells, and also indicated poor overall survival. Multispectral IHC indicated that CD155 was coexpressed with CD11b or CD11c in tumor-infiltrating stromal cells. Anti-TIGIT treatment significantly delayed tumor growth in transgenic HNSCC mouse models and enhanced antitumor immune responses by activating CD8⁺ T-cell effector function and reducing the population of Tregs. In vitro coculture studies showed that anti-TIGIT treatment significantly abrogated the immunosuppressive capacity of myeloid-derived suppressor cells (MDSC), by decreasing Arg1 transcripts, and Tregs, by reducing TGFβ1 secretion. In vivo depletion studies showed that the therapeutic efficacy by anti-TIGIT mainly relies on CD8⁺ T cells and Tregs. Blocking PD-1/PD-L1 signaling increased the expression of TIGIT on Tregs. These results present a translatable method to improve antitumor immune responses by targeting TIGIT/CD155 signaling in HNSCC.

Cancer Cell Membrane Camouflaged Nanoparticles to Realize Starvation Therapy Together with Checkpoint Blockades for Enhancing Cancer Therapy

Although anti-PD-1 immunotherapy is widely used to treat melanoma, its efficacy still has to be improved. In this work, we present a therapeutic method that combines immunotherapy and starvation therapy to achieve better antitumor efficacy. We designed the CMSN-GOx method, in which mesoporous silica nanoparticles (MSN) are loaded with glucose oxidase (GOx) and then encapsulate the surfaces of cancer cell membranes to realize starvation therapy. By functionalizing the MSN's biomimetic surfaces, we can synthesize nanoparticles that can escape the host immune system and homologous target. These attributes enable the nanoparticles to have improved cancer targeting ability and enrichment in tumor tissues. Our synthetic CMSN-GOx complex can ablate tumors and induce dendritic cell maturity to stimulate an antitumor immune response. We performed an in vivo analysis of these nanoparticles and determined that our combined therapy CMSN-GOx plus PD-1 exhibits a better antitumor therapeutic effect than therapies using CMSN-GOx or PD-1 alone. Additionally, we used the positron emission tomography imaging to measuring the level of glucose metabolism in tumor tissues, for which we investigate the effect with the cancer therapy in vivo.

Specific blockade CD73 alters the "exhausted" phenotype of T cells in head and neck squamous cell carcinoma

The adenosine-induced immunosuppression hampers the immune response toward tumor cells and facilitates the tumor cells to evade immunosurveillance. CD73, an ecto-5-nucleotidase, is the ectoenzyme dephosphorylating extracellular AMP to adenosine. Here, using immunocompetent transgenic head and neck squamous cell carcinoma (HNSCC) mouse model, immune profiling showed high expression of CD73 on CD4⁺ and CD8⁺ T cells was associated with an "exhausted" phenotype. Further, treatment with anti-CD73 monoclonal antibody (mAb) significantly blunted the tumor growth in the mouse model, and the blockade of CD73 reversed the "exhausted" phenotype of CD4⁺ and CD8⁺ T cells through downregulation of total expression of PD-1 and CTLA-4 on T cells. Whereas the population of CD4⁺ CD73^hi /CD8⁺ CD73^hi T cells expressed higher CTLA-4 and PD-1 as compared to untreated controls. In addition, the human tissue microarrays showed the expression of CD73 is upregulated on tumor infiltrating immune cells in patients with primary HNSCC. Moreover, CD73 expression is an independent prognostic factor for poor outcome in our cohort of HNSCC patients. Altogether, these findings highlight the immunoregulatory role of CD73 in the development of HNSCC and we propose that CD73 may prove to be a promising immunotherapeutic target for the treatment of HNSCC.

LAIR-1 overexpression and correlation with advanced pathological grade and immune suppressive status in oral squamous cell carcinoma

BACKGROUND

This study aims to investigate the characteristic role of inhibitory receptor leukocyte-associated immunoglobulin-like receptor 1 (LAIR-1) in oral squamous cell carcinoma (OSCC).

METHODS

The expressions of LAIR-1 and other immune-related molecules were detected in a human OSCC tissue microarray. LAIR-1 expression difference among different clinicopathological parameters was analyzed. The correlations of LAIR-1 with several immune-related markers were assessed.

RESULTS

Compared with dysplasia and oral mucosa, the expression of LAIR-1 was significantly upregulated in the stroma of OSCC, and its overexpression was correlated with advanced pathological grade. Overexpression of LAIR-1 was significantly associated with tumor-associated macrophage and myeloid-derived suppressor cell markers (CD68, CD163; CD33, CD11b), indoleamine 2,3-dioxygenase (IDO) and two immune checkpoints (B7-H3 and VISTA).

CONCLUSIONS

Overexpression of LAIR-1 was associated with advanced pathological grade and correlated with immune suppressive features in OSCC. Further studies are required to identify the specific immunological role of LAIR-1.

Inhibition of SRC family kinases facilitates anti-CTLA4 immunotherapy in head and neck squamous cell carcinoma

The immune system plays a critical role in the establishment, development, and progression of head and neck squamous cell carcinoma (HNSCC). As treatment with single-immune checkpoint agent results in a lower response rate in patients, it is important to investigate new strategies to maintain favorable anti-tumor immune response. Herein, the combination immunotherapeutic value of CTLA4 blockade and SFKs inhibition was assessed in transgenic HNSCC mouse model. Our present work showed that tumor growth was not entirely controlled when HNSCC model mice were administered anti-CTLA4 chemotherapeutic treatment. Moreover, it was observed that Src family kinases (SFKs) were hyper-activated and lack of anti-tumor immune responses following anti-CTLA4 chemotherapeutic treatment. We hypothesized that activation of SFKs is a mechanism of anti-CTLA4 immunotherapy resistance. We, therefore, carried out combined drug therapy using anti-CTLA4 mAbs and an SFKs' inhibitor, dasatinib. As expected, dasatinib and anti-CTLA4 synergistically inhibited tumor growth in Tgfbr1/Pten 2cKO mice. Furthermore, dasatinib and anti-CTLA4 combined to reduce the number of myeloid-derived suppressor cells and Tregs, increasing the CD8+ T cell-to-Tregs ratio. We also found that combining dasatinib with anti-CTLA4 therapy significantly attenuated the expression of p-STAT3Y705 and Ki67 in tumoral environment. These results suggest that combination therapy with SFKs inhibitors may be a useful therapeutic approach to increase the efficacy of anti-CTLA4 immunotherapy in HNSCC.

Overexpression of p21-activated kinase 2 is correlated with high-grade oral squamous cell carcinomas

Aim: p21-activated kinase 2 (PAK2) is overexpressed in several tumors but the expression of PAK2 in oral squamous cell carcinomas (OSCCs) remains unclear. Materials & methods: Immunohistochemistry was performed on human tissue microarrays containing 165 primary OSCC, 48 oral epithelial dysplasia and 43 normal oral mucosa. Results: PAK2 expression was increased in primary OSCC compared with normal mucosa and significantly increased in primary OSCC grade III compared with grade I, but independent of overall survival rate. Moreover, the expression of PAK2 was statistically correlated with Lck/Yes novel tyrosine kinase (LYN), zinc finger transcription factor Slug, tumor-associated macrophage marker CD163 and LAG3. Conclusion: Overexpression of PAK2 in OSCC may be associated with an advanced pathology grade.

Macrophage membrane-coated iron oxide nanoparticles for enhanced photothermal tumor therapy

Nanotechnology possesses the potential to revolutionize the diagnosis and treatment of tumors. The ideal nanoparticles used for in vivo cancer therapy should have long blood circulation times and active cancer targeting. Additionally, they should be harmless and invisible to the immune system. Here, we developed a biomimetic nanoplatform with the above properties for cancer therapy. Macrophage membranes were reconstructed into vesicles and then coated onto magnetic iron oxide nanoparticles (Fe₃O₄ NPs). Inherited from the Fe₃O₄ core and the macrophage membrane shell, the resulting Fe₃O₄@MM NPs exhibited good biocompatibility, immune evasion, cancer targeting and light-to-heat conversion capabilities. Due to the favorable in vitro and in vivo properties, biomimetic Fe₃O₄@MM NPs were further used for highly effective photothermal therapy of breast cancer in nude mice. Surface modification of synthetic nanomaterials with biomimetic cell membranes exemplifies a novel strategy for designing an ideal nanoplatform for translational medicine.

Anti-CD47 treatment enhances anti-tumor T-cell immunity and improves immunosuppressive environment in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is considered as an immunosuppressive disease, with impaired tumor-infiltrating T lymphocytes and increased suppressive immune cells. The efficacy of CD47 antibodies in immune checkpoint therapy is not clearly understood in HNSCC. In this study, human tissue microarrays and immunocompetent transgenic mouse models were used to explore the expression of CD47 and the use of CD47 antibodies in HNSCC. We identified overexpression of CD47 in HNSCC as compared with the control normal human tissue and also in HNSCC mouse models. The expression of CD47 also correlated with clinicopathological parameters as well as outcome. Furthermore, inhibition of CD47 delayed tumor growth and improved tumor microenvironment by stimulating effector T cells and decreasing suppressive immune cells and regulating the function of CD11b⁺ Ly6G⁺ MDSC. Our data suggest that CD47 blockade may be a potential immunotherapeutic target in human HNSCC.

TRAF6 regulates tumour metastasis through EMT and CSC phenotypes in head and neck squamous cell carcinoma

Epithelial–mesenchymal transition (EMT) is associated with metastasis formation, generation and maintenance of cancer stem cells (CSCs). However, the regulatory mechanisms of CSCs have not been clarified. This study aims to investigate the role of TNF receptor‐associated factor 6 (TRAF6) on EMT and CSC regulation in squamous cell carcinoma of head and neck (SCCHN). We found TRAF6 was overexpressed in human SCCHN tissues, and high TRAF6 expression was associated with lymphatic metastasis and resulted in poor prognosis in patients with SCCHN. In addition, elevated TRAF6 expression was observed in several HNSCC cell lines, and wound healing and transwell assay results showed that TRAF6 knockdown inhibited the migration and invasion ability of the SCCHN cells. Moreover, the expression of Vimentin, Slug and N‐cadherin was down‐regulated and that of E‐cadherin was elevated after TRAF6 knockdown but decreased by transforming growth factor beta 1 (TGF‐β1) and CAL27 similar to mesenchymal cells formed after TGF‐β1 induction. In addition, the expression levels of CD44, ALDH1, KLF4 and SOX2 were inhibited after TRAF6 knockdown, and the anchor‐dependent colony formation number and sphere number were remarkably reduced. Flow cytometry showed TRAF6 knockdown reduced ALDH1‐positive cancer stem cells. We also demonstrated that TRAF6 is closely associated with EMT process and cancer stem cells using a Tgfbr1/Pten 2cKO mice SCCHN model and human SCCHN tissue microarray. Our findings indicate that TRAF6 plays a role in EMT phenotypes, the generation and maintenance of CSCs in SCCHN, suggesting that TRAF6 is a potential therapeutic target for SCCHN.

γ-Secretase inhibitor reduces immunosuppressive cells and enhances tumour immunity in head and neck squamous cell carcinoma

Immune evasion is a hallmark feature of cancer, and it plays an important role in tumour initiation and progression. In addition, tumour immune evasion severely hampers the desired antitumour effect in multiple cancers. In this study, we aimed to investigate the role of the Notch pathway in immune evasion in the head and neck squamous cell carcinoma (HNSCC) microenvironment. We first demonstrated that Notch1 signaling was activated in a Tgfbr1/Pten-knockout HNSCC mouse model. Notch signaling inhibition using a γ-secretase inhibitor (GSI-IX, DAPT) decreased tumour burden in the mouse model after prophylactic treatment. In addition, flow cytometry analysis indicated that Notch signaling inhibition reduced the sub-population of myeloid-derived suppressor cells (MDSCs), tumour-associated macrophages (TAMs) and regulatory T cells (Tregs), as well as immune checkpoint molecules (PD1, CTLA4, TIM3 and LAG3), in the circulation and in the tumour. Immunohistochemistry (IHC) of human HNSCC tissues demonstrated that elevation of the Notch1 downstream target HES1 was correlated with MDSC, TAM and Treg markers and with immune checkpoint molecules. These results suggest that modulating the Notch signaling pathway may decrease MDSCs, TAMs, Tregs and immune checkpoint molecules in HNSCC.

NLRP3 inflammasome activation promotes inflammation-induced carcinogenesis in head and neck squamous cell carcinoma

Background

NLRP3 inflammasome acts as a danger signal sensor that triggers and coordinates the inflammatory response. However, the roles of NLRP3 inflammasome in the tumorigenesis and development of cancer stem cells (CSCs) of squamous cell carcinoma of the head and neck (SCCHN) remain ambiguous.

Methods

In our study, tissue microarrays, ELISA, sphere-forming assay, colony formation assay and Western blot analysis were performed to evaluate the effect of NLRP3 inflammasome on the development of CSCs in human SCCHN tissue specimen, cell lines, and transgenic mouse SCCHN model.

Results

The components of NLRP3 inflammasome, namely, NLRP3, ASC, Caspase-1, and IL-18 were correlated with CSCs markers BMI1, ALDH1 and CD44 in human SCCHN specimens. Moreover, NLRP3, Caspase-1, IL-1β, and IL-18 were highly expressed in SCCHN cell lines. NLRP3 inflammasome activated by LPS and ATP promoted sphere-forming and colony formation capacities along with an upregulation of BMI1, ALDH1 and CD44. In addition, NLRP3 inflammasome blockade by NLRP3 inhibitor MCC950 reduced sphere and colony number, also decreased the expression of BMI1, ALDH1 and CD44 in SCCHN cell lines. Expression of NLRP3, ASC, Caspase-1, IL-1β, IL-18, BMI1, ALDH1 and CD44 was upregulated in Tgfbr1/Pten 2cKO mouse SCCHN model, and NLRP3 inflammasome expression was closely related to those CSCs makers in mice SCCHN. However, MCC950 treatment reduced the expression of NLRP3 inflammasome, CSCs markers BMI1, ALDH1 and CD44 in Tgfbr1/Pten 2cKO mice SCCHN. In addition, blockade of NLRP3 inflammasome can also delayed the tumor-burdened speed in SCCHN mice.

Conclusions

Our study demonstrates that NLRP3 inflammasome was upregulated and associated with the carcinogenesis and CSCs self-renewal activation in SCCHN. NLRP3 inflammasome can be a potential target in the development of novel approaches for head and neck squamous cell carcinoma therapy.

Electronic supplementary material

The online version of this article (10.1186/s13046-017-0589-y) contains supplementary material, which is available to authorized users.

The Notch signaling pathway in head and neck squamous cell carcinoma: A meta-analysis

BACKGROUND

The Notch signaling pathway has been associated with the regulation of self-renewal capacity, cell cycle exit, and survival. However, the relationship between the Notch signaling pathway and HNSCC remains controversial.

OBJECTIVES

A meta-analysis was conducted to evaluate the role of Notch signaling pathway in HNSCC.

MATERIAL AND METHODS

Relevant studies published until March 31, 2015 were identified by searching the PubMed, EMBASE and Ovid database.

RESULTS

A total of 9 articles were eligible for this meta-analysis. The meta-analysis results showed that the expression of Notch1, Notch3 and NICD was significantly higher in HNSCC as compared with control tissue. There was no significant difference in Jagged1 and HES1 expression between HNSCC and control tissue. Stratified analysis results showed that the expression of Notch1 was significantly higher in poor differentiation, III and IV stage and positive lymph node metastasis patients. Additionally, over-expression of Notch1, NICD, HES1 and DLL4 significantly predicted poor OS in HNSCC patients.

CONCLUSION

The Notch signaling pathway plays an important role in tumor development of HNSCC. Inhibition of the Notch signaling pathway is a potential therapeutic method of HNSCC.

STAT3 Induces Immunosuppression by Upregulating PD-1/PD-L1 in HNSCC

Head and neck cancer is one of the most prevalent cancers around the world. Head and neck squamous cell carcinoma (HNSCC) accounts for nearly 90% of head and neck cancer. In recent years, significant advances have been made in immunotherapy for HNSCC. Although some clinical trials targeting immune checkpoints have shown success, the molecular mechanism for regulation of programmed death 1 (PD-1) and its ligand (PD-L1) is partially understood. In an effort to explore the effect of activation of signal transducers and activators of transcriptions (STAT3) on PD-1/PD-L1, the expression and correlation between phosphorylation of STAT3 and PD-1/PD-L1 were determined with immunostaining of human and mouse HNSCC tissue sections. PD-1/PD-L1 overexpression was found to be significantly associated with p-STAT3 in human and mouse HNSCC. Targeting STAT3 by a small molecule effectively inhibited the expression of PD-L1 in the CAL27 cell line. Furthermore, we found that blockade of STAT3 signaling downregulated PD-1/PD-L1 in a Tgfbr1/Pten 2cKO HNSCC mouse model. These findings suggest that STAT3 signaling plays an important role in PD-1/PD-L1 regulation and the antitumor immune response of HNSCC.

Blockade of adenosine A2A receptor enhances CD8+ T cells response and decreases regulatory T cells in head and neck squamous cell carcinoma

BACKGROUND

Cancer immunotherapy offers a promising approach in cancer treatment. The adenosine A2A receptor (A2AR) could protect cancerous tissues from immune clearance via inhibiting T cells response. To date, the role of A2AR in head and neck squamous cell carcinoma (HNSCC) has not been investigated. Here, we sought to explore the expression and immunotherapeutic value of A2AR blockade in HNSCC.

METHODS

The expression of A2AR was evaluated by immunostaining in 43 normal mucosae, 48 dysplasia and 165 primary HNSCC tissues. The immunotherapeutic value of A2AR blockade was assessed in vivo in genetically defined immunocompetent HNSCC mouse model.

RESULTS

Immunostaining of HNSCC tissue samples revealed that increased expression of A2AR on tumor infiltrating immune cells correlated with advanced pathological grade, larger tumor size and positive lymph node status. Elevated A2AR expression was also detected in recurrent HNSCC and HNSCC tissues with induction chemotherapy. The expression of A2AR was found to be significantly correlated with HIF-1α, CD73, CD8 and Foxp3. Furthermore, the increased population of CD4⁺Foxp3⁺ regulatory T cells (Tregs), which partially expressed A2AR, was observed in an immunocompetent mouse model that spontaneously develops HNSCC. Pharmacological blockade of A2AR by SCH58261 delayed the tumor growth in the HNSCC mouse model. Meanwhile, A2AR blockade significantly reduced the population of CD4⁺ Foxp3⁺ Tregs and enhanced the anti-tumor response of CD8⁺ T cells.

CONCLUSIONS

These results offer a preclinical proof for the administration of A2AR inhibitor on prophylactic experimental therapy of HNSCC and suggest that A2AR blockade can be a potential novel strategy for HNSCC immunotherapy.

Expression of VISTA correlated with immunosuppression and synergized with CD8 to predict survival in human oral squamous cell carcinoma

V-domain Ig suppressor of T cell activation (VISTA), a novel immune checkpoint regulatory molecule, suppresses T cell mediated immune responses. The aim of the present study was to profile the immunological expression, clinical significance and correlation of VISTA in human oral squamous cell carcinoma (OSCC). Human tissue microarrays, containing 165 primary OSCCs, 48 oral epithelial dysplasias and 43 normal oral mucosae, were applied to investigate the expression levels of VISTA, CD8, cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), programmed death ligand 1 (PD-L1), PI3Kα p110, IL13Rα2, phospho-STAT3 at tyrosine 705 (p-STAT3) and myeloid-derived suppressor cell (MDSC) markers (CD11b and CD33) by immunohistochemistry and digital pathology analysis. The results demonstrated that the protein level of VISTA was significantly higher in human OSCC specimens, and that VISTA expression in primary OSCCs was correlated with lymph node status. VISTA expression did not serve as an independent predictor for poor prognosis, while patient subgroup with VISTA high and CD8 low expression (22/165) had significantly poorer overall survival compared with other subgroups based on the multivariate and Cox hazard analyses among the primary OSCC patients in the present cohort. Additionally, the expression of VISTA was significantly correlated with PD-L1, CTLA-4, IL13Rα2, PI3K, p-STAT3, CD11b and CD33 according to Pearson's correlation coefficient test. Taken together, the results indicated that the VISTA high and CD8 low group, as an immunosuppressive subgroup, might be associated with a poor prognosis in primary OSCC. These findings indicated that VISTA might be a potential immunotherapeutic target in OSCC treatment.

Selective blockade of B7-H3 enhances antitumour immune activity by reducing immature myeloid cells in head and neck squamous cell carcinoma

Immature myeloid cells including myeloid-derived suppressor cells (MDSCs) and tumour-associated macrophages (TAMs) promote tumour growth and metastasis by facilitating tumour transformation and angiogenesis, as well as by suppressing antitumour effector immune responses. Therefore, strategies designed to reduce MDSCs and TAMs accumulation and their activities are potentially valuable therapeutic goals. In this study, we show that negative immune checkpoint molecule B7-H3 is significantly overexpressed in human head and neck squamous cell carcinoma (HNSCC) specimen as compared with normal oral mucosa. Using immunocompetent transgenic HNSCC models, we observed that targeting inhibition of B7-H3 reduced tumour size. Flow cytometry analysis revealed that targeting inhibition of B7-H3 increases antitumour immune response by decreasing immunosuppressive cells and promoting cytotoxic T cell activation in both tumour microenvironment and macroenvironment. Our study provides direct in vivo evidence for a rationale for B7-H3 blockade as a future therapeutic strategy to treat patients with HNSCC.

AGR2 promotes the proliferation, migration and regulates epithelial-mesenchymal transition in salivary adenoid cystic carcinoma

Salivary adenoid cystic carcinoma (AdCC) is a common head and neck cancer with the propensity for local spread and distant metastasis. In our previous study, elevated expression of Anterior gradient 2 (AGR2) was detected in head and neck squamous cell carcinoma (HNSCC), associated with epithelial-mesenchymal transition (EMT) and cancer stemness. However, to date, the expression and function of AGR2 in AdCC has yet to be elucidated. In the present study, human AdCC tissue microarrays including 18 cases of normal salivary gland (NSG), 12 cases of pleomorphic adenoma (PMA) and 72 cases of AdCC were employed for immunohistochemical staining analysis. Results indicated that AGR2, which was remarkably correlated with Ki-67, transforming growth factor beta-1 (TGF-β1) and CD147, was significantly elevated in human salivary AdCC tissues. Knockdown of AGR2 significantly repressed the proliferation and migration of human SACC-83 and SACC-LM cell lines. Additionally, AGR2 silencing obviously reversed the EMT phenomena induced by TGF-β1. Taken together, our present study revealed the potential pro-metastasis role of AGR2 in AdCC, indicating that AGR2 might be a novel therapeutic target of AdCC with distant metastasis.

T-cell immunoglobulin mucin 3 blockade drives an antitumor immune response in head and neck cancer

T‐cell immunoglobulin mucin 3 (TIM3) contributes to immune suppression during progression of many cancers, but the precise role of TIM3 in head and neck squamous cell carcinoma (HNSCC) is not clearly understood. In this study, we report that TIM3 expression was significantly up‐regulated in patients with HNSCC and associated with lymph node metastasis. Additionally, TIM3 expression was increased in patients with recurrent HNSCC and patients with preradiotherapy or prechemotherapy. We also characterized CD8⁺ T cells and CD11b⁺CD33⁺ myeloid‐derived suppressor cells (MDSCs) in human HNSCC, and found that their expression was positively correlated with TIM3 expression. To determine the underlying mechanism of TIM3 in immune response during HNSCC progression, we utilized the Tgfbr1/Pten 2cKO HNSCC mouse model with TIM3 overexpression. Treatment with anti‐TIM3 monoclonal antibody effectively suppressed tumor growth through restoring effector T‐cell function by targeting CD4⁺TIM3⁺ cells and CD8⁺TIM3⁺ cells and decreasing MDSCs. Our findings demonstrate TIM3 expression in patients with HNSCC and suggest anti‐TIM3 immunotherapy as a novel therapeutic approach for effective treatment of HNSCC.

Inhibition of SRC family kinases reduces myeloid-derived suppressor cells in head and neck cancer

SRC family kinases (SFKs), a group of nonreceptor tyrosine kinases, modulate multiple cellular functions, such as cell proliferation, differentiation and metabolism. SFKs display aberrant activity in progressive stages of human cancers. However, the precise role of SFKs in the head and neck squamous cell carcinoma (HNSCC) signaling network is far from clear. In this study, we found that the inhibition of SFKs activity by dasatinib effectively reduced the tumor size and population of MDSCs in the HNSCC mouse model. Molecular analysis indicates that phosphorylation of LYN, rather than SRC, was inhibited by dasatinib treatment. Next, we analyzed LYN expression by immunostaining and found that it was overexpressed in the human HNSCC specimens. Moreover, LYN expression in stromal cells positively correlated with myeloid-derived suppressor cells (MDSCs) makers CD11b and CD33 in human HNSCC. The dual positive expression of LYN in epithelial and stromal cells (EPI⁺ SRT⁺ ) was associated with unfavorable overall survival of HNSCC patients. These findings indicate that SFKs may be a potential target for an effective immunotherapy of HNSCC by decreasing MDSCs and moreover, LYN will have an impact on such therapeutic strategy.

Tumor growth suppression by inhibiting both autophagy and STAT3 signaling in HNSCC

Autophagy is considered as a double-edged sword. It can prolong the survival of cancer cells and enhance its resistance to apoptosis, and paradoxically, defective autophagy has been linked to increased tumorigenesis, but the mechanism behind this phenomenon is unclear. In this study, we demonstrated that decreased phosphorylation of signal transducer and activator of transcription 3 (p-STAT3) was correlated with increased autophagy through the Akt/mTOR and Erk signaling pathways in human head and neck squamous cell carcinoma (HNSCC). We also showed that blockage of STAT3 by NSC74859 could markedly induce apoptotic cell death and autophagy. Meanwhile, increased autophagy inhibited apoptosis. The pharmacological or genetic inhibition of autophagy and STAT3 further sensitized HNSCC cells to apoptosis. Furthermore, evidence from xenograft model proved that suppressed STAT3 activity combined with inhibition of autophagy promoted tumor regression better than either treatment alone. Taken together, this present study demonstrated that autophagy alleviates apoptotic cell death in HNSCC, and combination of inhibition of STAT3 by NSC74859 and autophagy might be a promising new therapeutic strategy for HNSCC.

LAG-3 confers poor prognosis and its blockade reshapes antitumor response in head and neck squamous cell carcinoma

Immunotherapy with immune checkpoint molecule-specific monoclonal antibody have obtained encouraging results from preclinical studies and clinical trials, which promoted us to explore whether this kind of immunotherapy could be applicable to head and neck squamous cell carcinoma (HNSCC). Lymphocyte activation gene-3 (LAG-3) is an immune checkpoint control protein that negatively regulates T cells and immune response. Here, using the human tissue samples, we report these findings that LAG-3 is overexpressed on tumor-infiltrating lymphocytes (TILs; p < 0.001) and its overexpression correlates with the high pathological grades, lager tumor size and positive lymph node status in human primary HNSCC. Survival analysis identifies LAG-3 as a prognostic factor independent of tumor size and pathological grades for primary HNSCC patients with negative lymph node status (p = 0.014). Study in immunocompetent genetically defined HNSCC mouse model reports that LAG-3 is upregulated on CD4⁺ T cells, CD8⁺ T cells and CD4⁺Foxp3⁺ regulatory T cells (Tregs). In vivo study, administration of LAG-3-specific antibody retards tumor growth in a way associated with enhanced systemic antitumor response by potentiating the antitumor response of CD8⁺ T cells and decreasing the population of immunosuppressive cells. Taken together, our results offer a preclinical proof supporting the immunomodulatory effects of LAG-3 and suggest a potential therapeutic target of immunotherapy for HNSCC.

PD-1 blockade attenuates immunosuppressive myeloid cells due to inhibition of CD47/SIRPα axis in HPV negative head and neck squamous cell carcinoma

Myeloid-derived suppressor cells (MDSCs) and tumor associated macrophages (TAMs) play key roles in the tumor immune suppressive network and tumor progression. However, precise roles of programmed death-1 (PD-1) in immunological functions of MDSCs and TAMs in head and neck squamous cell carcinoma (HNSCC) have not been clearly elucidated. In the present study, we show that PD-1 and PD-L1 levels were significantly higher in human HNSCC specimen than in normal oral mucosa. MDSCs and TAMs were characterized in mice and human HNSCC specimen, correlated well with PD-1 and PD-L1 expression. αPD-1 treatment was well tolerated and significantly reduced tumor growth in the HNSCC mouse model along with significant reduction in MDSCs and TAMs in immune organs and tumors. Molecular analysis suggests a reduction in the CD47/SIRPα pathway by PD-1 blockade, which regulates MDSCs, TAMs, dendritic cell as well as effector T cells. Hence, these data identify that PD-1/PD-L1 axis is significantly increased in human and mouse HNSCC. Adoptive αPD-1 immunotherapy may provide a novel therapeutic approach to modulate the micro- and macro- environment in HNSCC.

B7-H4 expression indicates poor prognosis of oral squamous cell carcinoma

Checkpoint blockade therapy utilizing monoclonal antibodies to reactivate T cells and recover their antitumor activity makes an epoch in cancer immunotherapy. The role of B7-H4, a novel negative immune checkpoint, in oral squamous cell carcinoma (OSCC) has still not been elucidated. In this study, tissue samples from human OSCC, which contains 165 primary OSCC, 48 oral epithelial dysplasia and 43 normal oral mucosa specimens, and Tgfbr1/Pten 2cKO mice OSCC model were stained with B7-H4 antibody to analyze the correlations between B7-H4 expression and clinicopathological characteristics. Kaplan-Meier analysis was used to compare the survival of patients with high B7-H4 expression and patients with low B7-H4 expression. We found B7-H4 is highly expressed in human OSCC tissue, and the B7-H4 expression level was associated with the clinicopathological parameters containing pathological grade and lymph node status. Moreover, we confirmed that B7-H4 was overexpressed in Tgfbr1/Pten 2cKO mice OSCC model. Our data also indicated that patients with high B7-H4 expression had poor overall survival compared with those with low B7-H4 expression. Furthermore, this study demonstrated that B7-H4 was positively associated with PD-L1, CD11b, CD33, PI3Kα p110, and p-S6 (S235/236). Taken together, these findings suggest B7-H4 is a potential target in the treatment of OSCC.

PAK2 promotes migration and proliferation of salivary gland adenoid cystic carcinoma

P21 activated kinase 2 (PAK2) is a member of Group I PAKs family and highly expressed in various cancers. Current studies have demonstrated that PAK2 played a pivotal role in tumor progression. However, the role of PAK2 in salivary adenoid cystic carcinoma is still unclear. This study aims to explore the expression and the function of PAK2 in AdCC. Human salivary gland tissue microarray, including 18 normal salivary glands (NSG), 12 pleomorphic adenoma (PMA) and 72 AdCC, and immunohistochemistry were used to evaluate the expression of PAK2. The result showed that PAK2 was significantly increased in AdCC compared with NSG and PMA. Then the Pearson correlation analysis using serial tissue sections showed a close correlation of PAK2 with Cyclin D1, Phospho-STAT3 at Tyrosine 705 (p-STAT3) and Ki-67. Further in vitro study utilizing PAK2 knockdown via siRNA transfection revealed significantly reduced migration and proliferation of AdCC cell lines compared with control group. Knockdown of PAK2 decreased the expression of Cyclin D1 in AdCC cell lines. In addition, the inhibition of STAT3 reduced the expression of PAK2 in AdCC cell lines. These findings suggested that PAK2 promotes AdCC cell migration and proliferation and may be a potential therapeutic target.

CTLA4 blockade reduces immature myeloid cells in head and neck squamous cell carcinoma

Immature myeloid cells such as myeloid-derived suppressor cells (MDSCs) and M2 macrophages play a vital role in the tumor immune escape and tumor progression. Cytotoxic T lymphocyte-associated antigen 4 (CTLA4), as a negative immune checkpoint, is highly expressed in numerous solid tumors. However, precise functions of CTLA4 in head and neck squamous cell carcinoma (HNSCC) have not yet been elucidated. In this study, we demonstrated that the ratio of CD8(+)/CTLA4 can be used as a potential index with a clinical prognostic value for HNSCC. Using immunocompetent transgenic mouse model with spontaneous HNSCC, we directly observed that targeting CTLA4 decreases MDSCs and M2 macrophages and promotes T cell activation in both tumor microenvironment and macro-environment. In all, our study provides direct evidence in vivo and proposes a rationale for CTLA4 inhibition as a future therapeutic strategy in patients with HNSCC.

Targeting STAT3 signaling reduces immunosuppressive myeloid cells in head and neck squamous cell carcinoma

Cumulative evidence suggests that constitutively activated signal transducer and activator of transcription (STAT3) may contribute to sustaining immunosuppressive status, and that inhibiting STAT3 signaling represents a potential strategy to improve antitumor immunity. In the present study, we observed that high levels phosphorylated of STAT3 are significantly associated with the markers for both myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) in human head and neck squamous cell carcinoma (HNSCC). Additionally, we showed that targeting STAT3 signaling with a tolerable selective inhibitor S3I-201 significantly decreased immature myeloid cells such as MDSCs, TAMs and iDCs in genetically defined mice HNSCC model. These findings highlight that targeting STAT3 signaling may be effective to enhance antitumor immunity via myeloid suppressor cells in HNSCC.

LAG-3 confers poor prognosis and its blockade reshapes antitumor response in head and neck squamous cell carcinoma

Immunotherapy with immune checkpoint molecule-specific monoclonal antibody have obtained encouraging results from preclinical studies and clinical trials, which promoted us to explore whether this kind of immunotherapy could be applicable to head and neck squamous cell carcinoma (HNSCC). Lymphocyte activation gene-3 (LAG-3) is an immune checkpoint control protein that negatively regulates T cells and immune response. Here, using the human tissue samples, we report these findings that LAG-3 is overexpressed on tumor-infiltrating lymphocytes (TILs; p < 0.001) and its overexpression correlates with the high pathological grades, lager tumor size and positive lymph node status in human primary HNSCC. Survival analysis identifies LAG-3 as a prognostic factor independent of tumor size and pathological grades for primary HNSCC patients with negative lymph node status (p = 0.014). Study in immunocompetent genetically defined HNSCC mouse model reports that LAG-3 is upregulated on CD4⁺ T cells, CD8⁺ T cells and CD4⁺Foxp3⁺ regulatory T cells (Tregs). In vivo study, administration of LAG-3-specific antibody retards tumor growth in a way associated with enhanced systemic antitumor response by potentiating the antitumor response of CD8⁺ T cells and decreasing the population of immunosuppressive cells. Taken together, our results offer a preclinical proof supporting the immunomodulatory effects of LAG-3 and suggest a potential therapeutic target of immunotherapy for HNSCC.

Red Blood Cell Membrane as a Biomimetic Nanocoating for Prolonged Circulation Time and Reduced Accelerated Blood Clearance

For decades, poly(ethylene glycol) (PEG) has been widely incorporated into nanoparticles for evading immune clearance and improving the systematic circulation time. However, recent studies have reported a phenomenon known as "accelerated blood clearance (ABC)" where a second dose of PEGylated nanomaterials is rapidly cleared when given several days after the first dose. Herein, we demonstrate that natural red blood cell (RBC) membrane is a superior alternative to PEG. Biomimetic RBC membrane-coated Fe(3)O(4) nanoparticles (Fe(3)O(4) @RBC NPs) rely on CD47, which is a "don't eat me" marker on the RBC surface, to escape immune clearance through interactions with the signal regulatory protein-alpha (SIRP-α) receptor. Fe(3)O(4) @RBC NPs exhibit extended circulation time and show little change between the first and second doses, with no ABC suffered. In addition, the administration of Fe(3)O(4) @RBC NPs does not elicit immune responses on neither the cellular level (myeloid-derived suppressor cells (MDSCs)) nor the humoral level (immunoglobulin M and G (IgM and IgG)). Finally, the in vivo toxicity of these cell membrane-camouflaged nanoparticles is systematically investigated by blood biochemistry, hematology testing, and histology analysis. These findings are significant advancements toward solving the long-existing clinical challenges of developing biomaterials that are able to resist both immune response and rapid clearance.

Epidermal growth factor receptor inhibition reduces angiogenesis via hypoxia-inducible factor-1α and Notch1 in head neck squamous cell carcinoma

Angiogenesis, a marker of cancer development, affects response to radiotherapy sensibility. This preclinical study aims to understand the receptor tyrosine kinase-mediated angiogenesis in head neck squamous cell carcinoma (HNSCC). The receptor tyrosine kinase activity in a transgenic mouse model of HNSCC was assessed. The anti-tumorigenetic and anti-angiogenetic effects of cetuximab-induced epidermal growth factor receptor (EGFR) inhibition were investigated in xenograft and transgenic mouse models of HNSCC. The signaling transduction of Notch1 and hypoxia-inducible factor-1α (HIF-1α) was also analyzed. EGFR was overexpressed and activated in the Tgfbr1/Pten deletion (2cKO) mouse model of HNSCC. Cetuximab significantly delayed tumor onset by reducing tumor angiogenesis. This drug exerted similar effects on heterotopic xenograft tumors. In the human HNSCC tissue array, increased EGFR expression correlated with increased HIF-1α and micro vessel density. Cetuximab inhibited tumor-induced angiogenesis in vitro and in vivo by significantly downregulating HIF-1α and Notch1. EGFR is involved in the tumor angiogenesis of HNSCC via the HIF-1α and Notch1 pathways. Therefore, targeting EGFR by suppressing hypoxia- and Notch-induced angiogenesis may benefit HNSCC therapy.

Notch signaling induces epithelial-mesenchymal transition to promote invasion and metastasis in adenoid cystic carcinoma

Epithelial-mesenchymal transition (EMT) is considered to have pivotal roles in the invasive and metastatic of Adenoid cystic carcinoma (AdCC) which is marked by local infiltration and distant metastasis. Notch signaling abnormity has been implicated as important molecular events in recent next generation sequencing studies of AdCC, but the detail is still unclear. This study was designed to investigate the expression of Notch signaling pathway and its relation with EMT program in AdCC. We constructed custom-made Tissue microarray (TMA) to evaluate the immunoreactivity of Notch signaling and EMT program and found that Notch signaling increase consecutively from NSG, PMA to AdCC, suggesting Notch signaling pathway may be associated with human AdCC progression. Then, we carried out Pearson correlation analysis and showed a close correlation of Notch signaling and EMT progression. When blocking Notch signaling pathway with γ-secretase inhibitor DAPT, EMT progression was decreased and migration and invasion ability were declined. Collectively, these findings suggest the vital roles of Notch signaling pathway in AdCC progression through their relationship with EMT progress. Targeting Notch signaling may provide further understanding of the mechanism of invasion and metastasis of AdCC as well as potential clinical therapeutics.

Inhibition of mTOR reduce Stat3 and PAI related angiogenesis in salivary gland adenoid cystic carcinoma

Angiogenesis is a complex biological process, which is involved in tumorigenesis and progression. However, the molecular mechanism of underlying angiogenesis remains largely unknown. In this study, we accessed the expression of proteins related angiogenesis by immunohistochemical staining of human tissue microarray which contains 72 adenoid cystic carcinoma (AdCC), 12 pleomorphic adenoma (PMA) and 18 normal salivary gland (NSG) using digital pathological scanner and scoring system. We found that the expression of p-S6(S235/236) (a downstream molecule of mTOR), p-Stat3(T705), PAI, EGFR, and HIF-1α was significantly increased in AdCC as compared with PMA and (or) NSG (p < 0.05). While, the expression of these proteins was not associated with pathological type of human AdCC (p > 0.05). Correlation analysis of these proteins revealed that p-S6(S235/236) up-regulates the expression of EGFR/p-Stat3(T705) (p < 0.05) and HIF-1α/PAI (p < 0.05). Moreover, the activation of p-S6(S235/236), EGFR/p-Stat3(T705) and HIF-1α/PAI associated with angiogenesis (CD34) and proliferation (Ki-67). In vitro, Rapamycin suppressed the expression of p-S6(S235/236), EGFR, p-Stat3(T705), HIF-1α and PAI. Further more, target inhibition of mTOR by rapamycin effectively reduced tumor growth of SACC-83 cells line nude mice xenograft and decreased the expression of p-S6(S235/236), EGFR/p-Stat3(T705) and HIF-1α/PAI. Taken together, these data revealed that mTOR signaling pathway regulates tumor angiogenesis by EGFR/p-Stat3(T705) and HIF-1α/PAI. Inhibition of mTOR by rapamycin could effectively reduced tumor growth. It is likely that mTOR inhibitors may be a potential candidate for treatment of AdCC.

Prognostic and predictive values of SPP1, PAI and caveolin-1 in patients with oral squamous cell carcinoma

SPP1, PAI and caveolin-1 are known to be closely associated with tumor progression in several kinds of human tumors. This study aimed to investigate the expression of SPP1, PAI and caveolin-1 in oral squamous cell carcinoma (OSCC), and to evaluate their association with the prognosis in oral carcinoma. Immunohistochemical staining was used to examine the expression of SPP1, PAI and caveolin-1 in 17 normal oral mucosa, 6 oral epithelial dysplasia and 43 OSCC specimens by tissue microarrays. High expression of SPP1, PAI and caveolin-1 was found in OSCC patients, and SPP1 and PAI expression were significantly higher in OSCC than in normal oral mucosa. No significant correlations were found between SPP1, PAI and caveolin-1 expression and clinicopathological factors. Expression of SPP1, PAI and caveolin-1 was also not associated with overall survival. Moreover, SPP1 was closely correlated with PAI, caveolin-1 and Keap1, and PAI had significant correlations with caveolin-1, Keap1 and Nrf2, and caveolin-1 was associated with Keap1 by using the Pearson correlation coefficient test. Our findings suggest that overexpressed SPP1, PAI and caveolin-1 were linked to carcinogenesis and progression, and thus they may serve as potential prognostic factors in OSCC.