Tumor hypoxia is associated with resistance to PD-1 blockade in squamous cell carcinoma of the head and neck

Reversal of T-cell exhaustion: Mechanisms and synergistic approaches

T cells suffer from long-term antigen stimulation and insufficient energy supply, leading to a decline in their effector functions, memory capabilities, and proliferative capacity, ultimately resulting in T cell exhaustion and an inability to perform normal immune functions in the tumor microenvironment. Therefore, exploring how to restore these exhausted T cells to a state with effector functions is of great significance. Exhausted T cells exhibit a spectrum of molecular alterations, such as heightened expression of inhibitory receptors, shifts in transcription factor profiles, and modifications across epigenetic, metabolic, and transcriptional landscapes. This review provides a comprehensive overview of various strategies to reverse T cell exhaustion, including immune checkpoint blockade, and explores the potential synergistic effects of combining multiple approaches to reverse T cell exhaustion. It offers new insights and methods for achieving more durable and effective reversal of T cell exhaustion.

Hypoxia-induced epigenetic regulation of breast cancer progression and the tumour microenvironment

The events that control breast cancer progression and metastasis are complex and intertwined. Hypoxia plays a key role both in oncogenic transformation and in fueling the metastatic potential of breast cancer cells. Here we review the impact of hypoxia on epigenetic regulation of breast cancer, by interfering with multiple aspects of the tumour microenvironment. The co-dependent relationship between oxygen depletion and metabolic shift to aerobic glycolysis impacts on a range of enzymes and metabolites available in the cell, promoting posttranslational modifications of histones and chromatin, and changing the gene expression landscape to facilitate tumour development. Hormone signalling, particularly through ERα, is also tightly regulated by hypoxic exposure, with HIF-1α expression being a prognostic marker for therapeutic resistance in ER+ breast cancers. This highlights the strong need to understand the hypoxia-endocrine signalling axis and exploit it as a therapeutic target. Furthermore, hypoxia has been shown to enhance metastasis in TNBC cells, as well as promoting resistance to taxanes, radiotherapy and even immunotherapy through microRNA regulation and changes in histone packaging. Finally, several other mediators of the hypoxic response are discussed. We highlight a link between ionic dysregulation and hypoxia signalling, indicating a potential connection between HIF-1α and tumoural Na+ accumulation which would be worth further exploration; we present the role of Ca2+ in mediating hypoxic adaptation via chromatin remodelling, transcription factor recruitment and changes in signalling pathways; and we briefly summarise some of the findings regarding vesicle secretion and paracrine induced epigenetic reprogramming upon hypoxic exposure in breast cancer. By summarising these observations, this article highlights the heterogeneity of breast cancers, presenting a series of pathways with potential for therapeutic applications.

Prolonged inhibition of intratumoral mast cells enhances efficacy of low-dose antiangiogenic therapy

Low-dose antiangiogenic therapies have demonstrated the ability to enhance normalization of tumor vessels, consequently improving hypoxia levels, drug delivery, and promoting anticancer immune responses. Mast cells have been identified as contributors to resistance against antiangiogenic therapy and facilitators of abnormal neoangiogenesis. In this study, we demonstrate that by simultaneously targeting intratumoral mast cells with Imatinib and administering low-dose anti-VEGFR2 therapy, antitumor efficacy can be enhanced in preclinical models. Thus, combinatory treatment overcomes therapy resistance, while concurrently promoting tumor vessel normalization. Notably, histomorphometric analysis of tumor sections revealed that vessel perfusion could be improved through mast cell inhibition and, despite a significantly reduced microvessel density, the combination treatment did not result in elevated tumor hypoxia levels compared to anti-VEGFR2 therapy alone. Short-term Imatinib application effectively increased antitumor efficacy, and by prolonging the application of Imatinib tumor vessel normalization was additionally improved. The combination of mast cell depletion and antiangiogenic treatments has not been investigated in detail and promises to help overcoming therapy resistance. Further studies will be required to explore their impact on other treatment approaches, and subsequently to validate these findings in a clinical setting.

Treatment with oncolytic vaccinia virus infects tumor-infiltrating regulatory and exhausted T cells

BACKGROUND

Oncolytic viruses (OVs) are an attractive way to increase immune infiltration into an otherwise cold tumor. While OVs are engineered to selectively infect tumor cells, there is evidence that they can infect other non-malignant cells in the tumor. We sought to determine if oncolytic vaccinia virus (VV) can infect lymphocytes in the tumor and, if so, how this was linked to therapeutic efficacy.

METHODS

To investigate infection of lymphocytes by VV, we used a GFP reporting VV in a murine head and neck squamous cell carcinoma tumor model. We also performed in vitro infection studies to determine the mechanism and consequences of VV lymphocyte infection by VV.

RESULTS

Our findings show that VV carries the capacity to infect proportions of immune cells, most notably T cells, after intratumoral treatment. Notably, this infection is preferential to terminally differentiated T cells that tend to reside in hypoxia. Infection of T cells leads to both virus production by the T cells as well as the eventual death of these cells. Using a mouse model which overexpressed the antiapoptotic protein Bcl2 in all T cells, we found that reducing T cell death following VV infection in MEER tumors reduced the number of complete regressions and reduced survival time compared with littermate control mice.

CONCLUSIONS

These findings suggest that OVs are capable of infecting more than just malignant cells after treatment, and that this infection may be an important part of the OV mechanism. We found that exhausted CD8+ T cells and regulatory CD4+ T cells were preferentially infected at early timepoints after treatment and subsequently died. When cell death in T cells was mitigated, mice responded poorly to VV treatment, suggesting that the deletion of these populations is critical to the therapeutic response to VV.

Evaluation of radiomics as a predictor of efficacy and the tumor immune microenvironment in anti-PD-1 mAb treated recurrent/metastatic squamous cell carcinoma of the head and neck patients

BACKGROUND

We retrospectively evaluated radiomics as a predictor of the tumor microenvironment (TME) and efficacy with anti-PD-1 mAb (IO) in R/M HNSCC.

METHODS

Radiomic feature extraction was performed on pre-treatment CT scans segmented using 3D slicer v4.10.2 and key features were selected using LASSO regularization method to build classification models with XGBoost algorithm by incorporating cross-validation techniques to calculate accuracy, sensitivity, and specificity. Outcome measures evaluated were disease control rate (DCR) by RECIST 1.1, PFS, and OS and hypoxia and CD8 T cells in the TME.

RESULTS

Radiomics features predicted DCR with accuracy, sensitivity, and specificity of 76%, 73%, and 83%, for OS 77%, 86%, 70%, PFS 82%, 75%, 89%, and in the TME, for high hypoxia 80%, 88%, and 72% and high CD8 T cells 91%, 83%, and 100%, respectively.

CONCLUSION

Radiomics accurately predicted the efficacy of IO and features of the TME in R/M HNSCC. Further study in a larger patient population is warranted.

A circadian rhythm-related lncRNA signature correlates with prognosis and tumor immune microenvironment in head and neck squamous cell carcinoma

OBJECTIVE

To investigate circadian rhythm-associated long non-coding RNA (lncRNA) signatures in predicting prognosis, metabolism, and immune infiltration in Head and Neck Squamous Cell Carcinoma (HNSC).

METHODS

HNSC samples were collected from the TCGA database. A signature was constructed using Cox regression and Least Absolute Shrinkage and Selection Operator (LASSO) methods. The immune cell infiltration was analyzed using CIBERSORT, ssGSEA, and MCPcounter. The RT-qPCR was used to detect the expression of signature lncRNAs.

RESULTS

A signature comprising 8 lncRNAs was constructed. The constructed signature demonstrated good prognostic prediction capability for HNSC. A nomogram encompassing risk score accurately predicted the long-term OS probability of HNSC. The infiltration levels of T cell, B cell and Macrophages were significantly higher in the high-risk group than in the low-risk group. Cluster analysis showed that the signature lncRNAs could classify the HNSC samples into two clusters. The RT-qPCR suggested that the expression of lncRNAs in signature was consistent with the data in TCGA.

CONCLUSION

The circadian rhythm-associated lncRNA signature has potential as a prognostic indicator for HNSC. It exhibits associations with metabolism, immune microenvironment, and drug sensitivity, thereby providing valuable insights for informing the treatment of HNSC.

Improving therapeutic strategies for Head and Neck Cancer: Insights from 3D hypoxic cell culture models in treatment response evaluation

Hypoxia in the tumor core negatively affects the outcome of patients with head and neck squamous cell carcinoma (HNSCC). Nevertheless, its role in predicting treatment response requires further exploration. Typically, reduced oxygen levels in the tumor core correlate with diminished efficacy of radiotherapy, chemotherapy, and immunotherapy, which are commonly used for HNSCC patients' treatment. Understanding the mechanistic underpinnings of these varied treatment responses in HNSCC is crucial for enhancing therapeutic outcomes and extending patients' overall survival (OS) rates. Standard monolayer cell culture conditions have major limitations in mimicking tumor physiological features and the complexity of the tumor microenvironment. Three-dimensional (3D) cell cultures enable the recreation of the in vivo tumor attributes, encompassing oxygen and nutrient gradients, cellular morphology, and intracellular connections. It is vital to use the 3D model in treatment response studies to mimic the tumor microenvironment, as evidenced by the decreased sensitivity of 3D structures to anticancer therapy. Accordingly, the aim of the study was to delineate the utility of the 3D models of hypoxic head and neck tumors in drug screening and treatment response studies.

Ramucirumab in combination with pembrolizumab for recurrent or metastatic head and neck squamous cell carcinoma: a single-centre, phase 1/2 trial

BACKGROUND

VEGF, a key mediator of angiogenesis and resistance to immunotherapy, is overexpressed in head and neck squamous cell carcinoma (HNSCC). We aimed to determine the recommended phase 2 dose of ramucirumab, a selective VEGFR2 inhibitor, given with pembrolizumab and the objective response rate of this combination as first-line treatment for recurrent or metastatic HNSCC.

METHODS

In this single-centre, phase 1/2 trial, which was done at Washington University (St Louis, MO, USA), eligible patients were aged 18 years or older with incurable recurrent or metastatic HNSCC and an Eastern Cooperative Oncology Group performance status of 0-2. Patients in phase 2 were required to have had no previous systemic therapy for recurrent or metastatic disease. In a dose de-escalation phase 1 design, patients received ramucirumab (starting dose 10 mg/kg given intravenously) and pembrolizumab (200 mg intravenously) on day 1 of each 21-day cycle. The recommended phase 2 dose of ramucirumab was defined as the highest dose at which one or fewer of three patients had dose-limiting toxicity during cycle one (primary endpoint of phase 1). In a Simon's two-stage phase 2 design, patients received the recommended phase 2 dose of ramucirumab and pembrolizumab. Tumour response (primary endpoint of phase 2) was assessed by Response Evaluation Criteria in Solid Tumours (version 1.1). We hypothesised that there would be an objective response rate of 32% or higher (null ≤13%). Eight or more responses among 33 evaluable patients (those with at least one response assessment) was evidence for activity (80% power; one-sided α=0·05). Analyses were done per protocol. The trial is registered with ClinicalTrials.gov, NCT03650764, and is closed to enrolment.

FINDINGS

Between June 18, 2019, and Feb 11, 2021, three patients enrolled and were treated in phase 1 and 37 patients in phase 2. Median age of all patients was 64 years (IQR 59-72). 36 (90%) of 40 patients were men and four (10%) were women, and 36 (90%) patients were White, three (8%) were Black or African American, and one (3%) was Asian. In phase 1, no dose-limiting toxicity event occurred. The recommended phase 2 dose of ramucirumab was 10 mg/kg. Median follow-up for patients on phase 2 was 14·8 months (IQR 4·9-31·0). In phase 2, 18 (55%; 95% CI 38-70) of 33 evaluable patients had an objective response, including confirmed complete response in 11 patients, confirmed partial response in six patients, and unconfirmed partial response in one patient. The most common grade 3 or worse adverse events were dysphagia (14 [38%] of 37 patients), lung infection (11 [30%]), lymphocyte count decrease (ten [27%]), hypophosphataemia (nine [24%]), and hypertension (eight [22%]). No treatment-related deaths were recorded.

INTERPRETATION

Ramucirumab and pembrolizumab were safe to administer to patients with recurrent or metastatic HNSCC, and the objective response rate with this combination as first-line treatment for recurrent or metastatic HNSCC was favourable. Further studies of ramucirumab and pembrolizumab in patients with recurrent or metastatic HNSCC are warranted.

FUNDING

Lilly and the Joseph Sanchez Foundation.

Multi omics analysis of mitophagy subtypes and integration of machine learning for predicting immunotherapy responses in head and neck squamous cell carcinoma

Mitophagy serves as a critical mechanism for tumor cell death, significantly impacting the progression of tumors and their treatment approaches. There are significant challenges in treating patients with head and neck squamous cell carcinoma, underscoring the importance of identifying new targets for therapy. The function of mitophagy in head and neck squamous carcinoma remains uncertain, thus investigating its impact on patient outcomes and immunotherapeutic responses is especially crucial. We initially analyzed the differential expression, prognostic value, intergene correlations, copy number variations, and mutation frequencies of mitophagy-related genes at the pan-cancer level. Through unsupervised clustering, we divided head and neck squamous carcinoma into three subtypes with distinct prognoses, identified the signaling pathway features of each subtype using ssGSEA, and characterized subtype B as having features of an immune desert using various immune infiltration calculation methods. Using multi-omics data, we identified the genomic variation characteristics, mutated gene pathway features, and drug sensitivity features of the mitophagy subtypes. Utilizing a combination of 10 machine learning algorithms, we have developed a prognostic scoring model called Mitophagy Subgroup Risk Score (MSRS), which is used to predict patient survival and the response to immune checkpoint blockade therapy. Simultaneously, we applied MSRS to single-cell analysis to explore intercellular communication. Through laboratory experiments, we validated the biological function of SLC26A9, one of the genes in the risk model. In summary, we have explored the significant role of mitophagy in head and neck tumors through multi-omics data, providing new directions for clinical treatment.

Understanding Hypoxia-Driven Tumorigenesis: The Interplay of HIF1A, DNA Methylation, and Prolyl Hydroxylases in Head and Neck Squamous Cell Carcinoma

Hypoxia-inducible factor 1-alpha (HIF1A) is a key transcription factor aiding tumor cells' adaptation to hypoxia, regulated by the prolyl hydroxylase family (EGLN1-3) by directing toward degradation pathways. DNA methylation potentially influences EGLN and HIF1A levels, impacting cellular responses to hypoxia. We examined 96 HNSCC patients and three cell lines, analyzing gene expression of EGLN1-3, HIF1A, CA9, VEGF, and GLUT1 at the mRNA level and EGLN1 protein levels. Methylation levels of EGLNs and HIF1A were assessed through high-resolution melting analysis. Bioinformatics tools were employed to characterize associations between EGLN1-3 and HIF1A expression and methylation. We found significantly higher mRNA levels of EGLN3, HIF1A, GLUT1, VEGF, and CA9 (p = 0.021; p < 0.0001; p < 0.0001; p = 0.004, and p < 0.0001, respectively) genes in tumor tissues compared to normal ones and downregulation of the EGLN1 mRNA level in tumor tissues (p = 0.0013). In HNSCC patients with hypermethylation of HIF1A in normal tissue, we noted a reduction in HIF1A mRNA levels compared to tumor tissue (p = 0.04). In conclusion, the differential expression of EGLN and HIF1A genes in HNSCC tumors compared to normal tissues influences patients' overall survival, highlighting their role in tumor development. Moreover, DNA methylation could be responsible for HIF1A suppression in the normal tissues of HNSCC patients.

Antiangiogenic-immune-checkpoint inhibitor combinations: lessons from phase III clinical trials

Antiangiogenic agents, generally antibodies or tyrosine-kinase inhibitors that target the VEGF-VEGFR pathway, are currently among the few combination partners clinically proven to improve the efficacy of immune-checkpoint inhibitors (ICIs). This benefit has been demonstrated in pivotal phase III trials across different cancer types, some with practice-changing results; however, numerous phase III trials have also had negative results. The rationale for using antiangiogenic drugs as partners for ICIs relies primarily on blocking the multiple immunosuppressive effects of VEGF and inducing several different vascular-modulating effects that can stimulate immunity, such as vascular normalization leading to increased intratumoural blood perfusion and flow, and inhibition of pro-apoptotic effects of endothelial cells on T cells, among others. Conversely, VEGF blockade can also cause changes that suppress antitumour immunity, such as increased tumour hypoxia, and reduced intratumoural ingress of co-administered ICIs. As a result, the net clinical benefits from antiangiogenic-ICI combinations will be determined by the balance between the opposing effects of VEGF signalling and its inhibition on the antitumour immune response. In this Perspective, we summarize the results from the currently completed phase III trials evaluating antiangiogenic agent-ICI combinations. We also discuss strategies to improve the efficacy of these combinations, focusing on aspects that include the deleterious functions of VEGF-VEGFR inhibition on antitumour immunity, vessel co-option as a driver of non-angiogenic tumour growth, clinical trial design, or the rationale for drug selection, dosing and scheduling.

Biophysical and biochemical aspects of immune cell-tumor microenvironment interactions

The tumor microenvironment (TME), composed of and influenced by a heterogeneous set of cancer cells and an extracellular matrix, plays a crucial role in cancer progression. The biophysical aspects of the TME (namely, its architecture and mechanics) regulate interactions and spatial distributions of cancer cells and immune cells. In this review, we discuss the factors of the TME-notably, the extracellular matrix, as well as tumor and stromal cells-that contribute to a pro-tumor, immunosuppressive response. We then discuss the ways in which cells of the innate and adaptive immune systems respond to tumors from both biochemical and biophysical perspectives, with increased focus on CD8+ and CD4+ T cells. Building upon this information, we turn to immune-based antitumor interventions-specifically, recent biophysical breakthroughs aimed at improving CAR-T cell therapy.

Notch signaling pathway in cancer: from mechanistic insights to targeted therapies

Notch signaling, renowned for its role in regulating cell fate, organ development, and tissue homeostasis across metazoans, is highly conserved throughout evolution. The Notch receptor and its ligands are transmembrane proteins containing epidermal growth factor-like repeat sequences, typically necessitating receptor-ligand interaction to initiate classical Notch signaling transduction. Accumulating evidence indicates that the Notch signaling pathway serves as both an oncogenic factor and a tumor suppressor in various cancer types. Dysregulation of this pathway promotes epithelial-mesenchymal transition and angiogenesis in malignancies, closely linked to cancer proliferation, invasion, and metastasis. Furthermore, the Notch signaling pathway contributes to maintaining stem-like properties in cancer cells, thereby enhancing cancer invasiveness. The regulatory role of the Notch signaling pathway in cancer metabolic reprogramming and the tumor microenvironment suggests its pivotal involvement in balancing oncogenic and tumor suppressive effects. Moreover, the Notch signaling pathway is implicated in conferring chemoresistance to tumor cells. Therefore, a comprehensive understanding of these biological processes is crucial for developing innovative therapeutic strategies targeting Notch signaling. This review focuses on the research progress of the Notch signaling pathway in cancers, providing in-depth insights into the potential mechanisms of Notch signaling regulation in the occurrence and progression of cancer. Additionally, the review summarizes pharmaceutical clinical trials targeting Notch signaling for cancer therapy, aiming to offer new insights into therapeutic strategies for human malignancies.

Hypoxic tumor microenvironment: Destroyer of natural killer cell function

In recent years, immunotherapy has made remarkable progress in treating certain tumors and hematological malignancies. However, the efficacy of natural killer (NK) cells, which are an important subset of innate lymphocytes used in anticancer immunotherapy, remains limited. Hypoxia, a critical characteristic of the tumor microenvironment (TME), is involved in tumor development and resistance to radiotherapy, chemotherapy, and immunotherapy. Moreover, hypoxia contributes to the impairment of NK cell function and may be a significant factor that limits their therapeutic effects. Targeted hypoxia therapy has emerged as a promising research area for enhancing the efficacy of NK cell therapy. Therefore, understanding how the hypoxic TME influences NK cell function is crucial for improving antitumor treatment outcomes.

Emerging therapeutic frontiers in cancer: insights into posttranslational modifications of PD-1/PD-L1 and regulatory pathways

The interaction between programmed cell death ligand 1 (PD-L1), which is expressed on the surface of tumor cells, and programmed cell death 1 (PD-1), which is expressed on T cells, impedes the effective activation of tumor antigen-specific T cells, resulting in the evasion of tumor cells from immune-mediated killing. Blocking the PD-1/PD-L1 signaling pathway has been shown to be effective in preventing tumor immune evasion. PD-1/PD-L1 blocking antibodies have garnered significant attention in recent years within the field of tumor treatments, given the aforementioned mechanism. Furthermore, clinical research has substantiated the efficacy and safety of this immunotherapy across various tumors, offering renewed optimism for patients. However, challenges persist in anti-PD-1/PD-L1 therapies, marked by limited indications and the emergence of drug resistance. Consequently, identifying additional regulatory pathways and molecules associated with PD-1/PD-L1 and implementing judicious combined treatments are imperative for addressing the intricacies of tumor immune mechanisms. This review briefly outlines the structure of the PD-1/PD-L1 molecule, emphasizing the posttranslational modification regulatory mechanisms and related targets. Additionally, a comprehensive overview on the clinical research landscape concerning PD-1/PD-L1 post-translational modifications combined with PD-1/PD-L1 blocking antibodies to enhance outcomes for a broader spectrum of patients is presented based on foundational research.

Inhibition of PTPN3 Expressed in Activated Lymphocytes Enhances the Antitumor Effects of Anti-PD-1 Therapy in Head and Neck Cancer, Especially in Hypoxic Environments

In the tumor microenvironment, wherein cytotoxic lymphocytes interact with cancer cells, lymphocyte exhaustion, an immune checkpoint inhibitor target, is promoted. However, the efficacy of these inhibitors is limited, and improving response rates remains challenging. We previously reported that protein tyrosine phosphatase nonreceptor type (PTPN) 3 is a potential immune checkpoint molecule for activated lymphocytes and that PTPN3 inhibition should be a focus area for cancer immunotherapy development. Therefore, in this study, we focused on PTPN3-suppressive therapy in terms of lymphocyte exhaustion under hypoxic conditions, which are a cancer microenvironment, and investigated measures for improving the response to anti-programmed death receptor (PD)-1 antibody drugs. We found that PTPN3 expression was upregulated in activated lymphocytes under hypoxic conditions, similar to the findings for other immune checkpoint molecules, such as PD-1, T cell immunoglobulin mucin-3, and lymphocyte-activation gene-3; furthermore, it functioned as a lymphocyte exhaustion marker. In addition, PTPN3-suppressed activated lymphocytes promoted the mammalian target of rapamycin (mTOR)-Akt signaling pathway activation and enhanced proliferation, migration, and cytotoxic activities under hypoxic conditions. Furthermore, PTPN3 suppression in activated lymphocytes increased PD-1 expression and enhanced the antitumor effects of anti-PD-1 antibody drugs against head and neck cancer in vitro and in vivo. These results suggest that the suppression of PTPN3 expression in activated lymphocytes enhances the therapeutic effect of anti-PD-1 antibody drugs in head and neck cancer, especially under hypoxic conditions that cause lymphocyte exhaustion.

Morusin suppresses the stemness characteristics of gastric cancer cells induced by hypoxic microenvironment through inhibition of HIF-1α accumulation

Gastric cancer (GC) is a common, life-threatening malignancy that contributes to the global burden of cancer-related mortality, as conventional therapeutic modalities show limited effects on GC. Hence, it is critical to develop novel agents for GC therapy. Morusin, a typical prenylated flavonoid, possesses antitumor effects against various cancers. The present study aimed to demonstrate the inhibitory effect and mechanism of morusin on the stemness characteristics of human GC in vitro under hypoxia and to explore the potential molecular mechanisms. The effects of morusin on cell proliferation and cancer stem cell-like properties of the human GC cell lines SNU-1 and AGS were assessed by MTT assay, colony formation test, qRT-PCR, flow cytometry analysis, and sphere formation test under hypoxia or normoxia condition through in vitro assays. The potential molecular mechanisms underlying the effects of morusin on the stem-cell-like properties of human GC cells in vitro were investigated by qRT-PCR, western blotting assay, and immunofluorescence assay by evaluating the nuclear translocation and expression level of hypoxia-inducible factor-1α (HIF-1α). The results showed that morusin exerted growth inhibitory effects on SNU-1 and AGS cells under hypoxia in vitro. Moreover, the proportions of CD44+/CD24- cells and the sphere formation ability of SNU-1 and AGS reduced in a dose-dependent manner following morusin treatment. The expression levels of stem cell-related genes, namely Nanog, OCT4, SOX2, and HIF-1α, gradually decreased, and the nuclear translocation of the HIF-1α protein was apparently attenuated. HIF-1α overexpression partially reversed the abovementioned effects of morusin. Taken together, morusin could restrain stemness characteristics of GC cells by inhibiting HIF-1α accumulation and nuclear translocation and could serve as a promising compound for GC treatment.

Optimizing Oxygen-Production Kinetics of Manganese Dioxide Nanoparticles Improves Hypoxia Reversal and Survival in Mice with Bone Metastases

Persistent hypoxia in bone metastases induces an immunosuppressive environment, limiting the effectiveness of immunotherapies. To address chronic hypoxia, we have developed manganese dioxide (MnO2) nanoparticles with tunable oxygen production kinetics for sustained oxygenation in bone metastases lesions. Using polyethylene glycol (PEG)-stabilized MnO2 or poly(lactic[50]-co-glycolic[50] acid) (50:50 PLGA), poly(lactic[75]-co-glycolic[25] acid) (75:25 PLGA), and polylactic acid (PLA)-encapsulated MnO2 NPs, we demonstrate that polymer hydrophobicity attenuates burst oxygen production and enables tunable oxygen production kinetics. The PEG-MnO2 NPs resulted in rapid hypoxia reduction in spheroids, which was rapidly attenuated, while the PLA-MnO2 NPs exhibited delayed hypoxia control in cancer spheroids. The 50:50 PLGA-MnO2 NPs exhibited the best short- and long-term control of hypoxia in cancer spheroids, resulting in sustained regulation of the expression of HIF-1α and immunosuppressive genes. The sustained control of hypoxia by the 50:50 PLGA-MnO2 NPs enhanced the cytotoxicity of natural killer cells against cancer spheroids. In vivo, 50:50 PLGA-MnO2 showed greater accumulation in the long bones and pelvis, common sites for bone metastases. The NPs decreased hypoxia in bone metastases and decreased regulatory T cell levels, resulting in enhanced survival of mice with established bone metastases.

Tumour response to hypoxia: understanding the hypoxic tumour microenvironment to improve treatment outcome in solid tumours

Hypoxia is a common feature of solid tumours affecting their biology and response to therapy. One of the main transcription factors activated by hypoxia is hypoxia-inducible factor (HIF), which regulates the expression of genes involved in various aspects of tumourigenesis including proliferative capacity, angiogenesis, immune evasion, metabolic reprogramming, extracellular matrix (ECM) remodelling, and cell migration. This can negatively impact patient outcomes by inducing therapeutic resistance. The importance of hypoxia is clearly demonstrated by continued research into finding clinically relevant hypoxia biomarkers, and hypoxia-targeting therapies. One of the problems is the lack of clinically applicable methods of hypoxia detection, and lack of standardisation. Additionally, a lot of the methods of detecting hypoxia do not take into consideration the complexity of the hypoxic tumour microenvironment (TME). Therefore, this needs further elucidation as approximately 50% of solid tumours are hypoxic. The ECM is important component of the hypoxic TME, and is developed by both cancer associated fibroblasts (CAFs) and tumour cells. However, it is important to distinguish the different roles to develop both biomarkers and novel compounds. Fibronectin (FN), collagen (COL) and hyaluronic acid (HA) are important components of the ECM that create ECM fibres. These fibres are crosslinked by specific enzymes including lysyl oxidase (LOX) which regulates the stiffness of tumours and induces fibrosis. This is partially regulated by HIFs. The review highlights the importance of understanding the role of matrix stiffness in different solid tumours as current data shows contradictory results on the impact on therapeutic resistance. The review also indicates that further research is needed into identifying different CAF subtypes and their exact roles; with some showing pro-tumorigenic capacity and others having anti-tumorigenic roles. This has made it difficult to fully elucidate the role of CAFs within the TME. However, it is clear that this is an important area of research that requires unravelling as current strategies to target CAFs have resulted in worsened prognosis. The role of immune cells within the tumour microenvironment is also discussed as hypoxia has been associated with modulating immune cells to create an anti-tumorigenic environment. Which has led to the development of immunotherapies including PD-L1. These hypoxia-induced changes can confer resistance to conventional therapies, such as chemotherapy, radiotherapy, and immunotherapy. This review summarizes the current knowledge on the impact of hypoxia on the TME and its implications for therapy resistance. It also discusses the potential of hypoxia biomarkers as prognostic and predictive indictors of treatment response, as well as the challenges and opportunities of targeting hypoxia in clinical trials.

Associations between HIFs and tumor immune checkpoints: mechanism and therapy

Hypoxia, which activates a variety of signaling pathways to enhance tumor cell growth and metabolism, is among the primary features of tumor cells. Hypoxia-inducible factors (HIFs) have a substantial impact on a variety of facets of tumor biology, such as epithelial-mesenchymal transition, metabolic reprogramming, angiogenesis, and improved radiation resistance. HIFs induce hypoxia-adaptive responses in tumor cells. Many academics have presented preclinical and clinical research targeting HIFs in tumor therapy, highlighting the potential applicability of targeted HIFs. In recent years, the discovery of numerous pharmacological drugs targeting the regulatory mechanisms of HIFs has garnered substantial attention. Additionally, HIF inhibitors have attained positive results when used in conjunction with traditional oncology radiation and/or chemotherapy, as well as with the very promising addition of tumor immunotherapy. Immune checkpoint inhibitors (CPIs), which are employed in a range of cancer treatments over the past decades, are essential in tumor immunotherapy. Nevertheless, the use of immunotherapy has been severely hampered by tumor resistance and treatment-related toxicity. According to research, HIF inhibitors paired with CPIs may be game changers for multiple malignancies, decreasing malignant cell plasticity and cancer therapy resistance, among other things, and opening up substantial new pathways for immunotherapy drug development. The structure, activation mechanisms, and pharmacological sites of action of the HIF family are briefly reviewed in this work. This review further explores the interactions between HIF inhibitors and other tumor immunotherapy components and covers the potential clinical use of HIF inhibitors in combination with CPIs.

Multi-omics Analysis Identifies Hypoxia Subtypes and S100A2 as an Immunosuppressive Factor in Cervical Cancer

Cervical cancer is a common gynecological oncology. Growing evidence indicates hypoxia plays an important role in tumor progression and immunity. However, no study has examined the hypoxia landscape in cervical cancer. In this study, using hierarchical clustering, we identified three hypoxia subtypes in cervical cancer samples from The Cancer Genome Atlas dataset according to formerly described hypoxia-related genes. The overall survival time, hypoxic features, genomics, and immunological characteristics of these subtypes existed distinct differences. We also created a hypoxia score by principle component analysis for dimension reduction. The hypoxiaScore was an effective prognostic biomarker validated by GSE44001 and was associated with immunotherapy response. Furthermore, combined with single-cell RNA-sequence (scRNA-seq) and experiments, S100A2 was identified as an immunosuppressive factor induced by hypoxia and regulated expression of PD-L1. S100A2 also served as an oncogene promoting the proliferation and migration of cervical cancer cells. These findings depicted a new hypoxia-based classification and identified S100A2 as a potential therapeutic target for cervical cancer, thereby advancing the understanding of immunotherapy resistance mechanisms and cervical cancer genetic markers.

A systematic review and meta-analysis of prognostic indicators in patients with head and neck malignancy treated with immune checkpoint inhibitors

INTRODUCTION

Tumor immunotherapy has recently emerged as a crucial focal point in oncology treatment research. Among tumor immunotherapy approaches, tumor immune checkpoint inhibitors (ICIs) have attracted substantial attention in clinical research. However, this treatment modality has benefitted only a limited number of patients. We conducted a meta-analysis of various biomarkers to decipher their prognostic implications in patients with head and neck squamous cell carcinoma (HNSCC) who are treated with ICIs, and thus identify predictive markers with practical clinical relevance.

METHODS

A systematic search of electronic databases was conducted to identify clinical studies that examined the correlation between biomarkers and treatment outcomes in the HNSCC patients. The included articles were screened and analyzed to extract data regarding overall survival (OS) and progression-free survival (PFS).

RESULTS

The relationship between the biomarkers included in the summary and prognosis was as follows: HPV positivity was associated with improved OS (HR = 0.76, 95% CI = 0.58-1.99), PFS (HR = 1.16, 95% CI = 0.81-1.67), and response (OR = 1.67, 95% CI = 1.37-2.99). PD-L1 positivity was associated with OS (HR = 0.71, 95% CI = 0.59-0.85), PFS (HR = 0.56 95% CI = 0.43-0.73), and response (OR = 2.16, 95% CI = 1.51-3.10). Neither HPV positivity nor PD-L1 positivity was associated with DCR. The following markers were collected for OS and PFS data and were associated with longer OS: lower Glasgow prognostic score (GPS/mGPS) grading, lower PS grading, high body mass index (BMI), low neutrophil-to-lymphocyte ratio (NLR), low platelet-to-lymphocyte ratio (PLR), high albumin (Alb), low lactate dehydrogenase (LDH). Factors associated with better PFS were lower GPS/mGPS grading, lower PS grading, high BMI, low NLR, high absolute lymphocyte count, and low LDH. Hyperprogressive disease was associated with worse OS and PFS. Fewer clinical studies have been completed on the tumor microenvironment and hypoxia, microsatellite instability/DNA mismatch repair, and microbiome and systematic analysis is difficult.

CONCLUSION

In our meta-analysis, different immune checkpoint factors were associated with different prognoses in HNSCC patients receiving immunotherapy. HPV, PD-L1, BMI, Alb, HPD, PS, GPS/mGPS, LDH, NLR, and PLR predicted the ICI outcome in HNSCC patients.

TH-302-loaded nanodrug reshapes the hypoxic tumour microenvironment and enhances PD-1 blockade efficacy in gastric cancer

BACKGROUND

Hypoxia, a common characteristic of the tumour microenvironment, is involved in tumour progression and immune evasion. Targeting the hypoxic microenvironment has been implicated as a promising antitumour therapeutic strategy. TH-302 can be selectively activated under hypoxic conditions. However, the effectiveness of TH-302 in gastric cancer combined immunotherapy remains unclear.

METHODS

We designed mPEG-PLGA-encapsulated TH-302 (TH-302 NPs) to target the hypoxic area of tumour tissues. A particle size analyzer was used to measure the average size and zeta potential of TH-302 NPs. The morphology was observed by transmission electron microscopy and scanning electron microscopy. The hypoxic area of tumour tissues was examined by immunofluorescence assays using pimonidazole. Flow cytometry analysis was performed to measure the levels of TNF-α, IFN-γ, and granzyme B. The synergistic antitumour activity of the combination of TH-302 NPs with anti-PD-1 (α-PD-1) therapy was assessed in vitro and in vivo. Haematoxylin and eosin staining of major organs and biochemical indicator detection were performed to investigate the biological safety of TH-302 NPs in vivo.

RESULTS

TH-302 NPs inhibited the proliferation and promoted the apoptosis of gastric cancer cells under hypoxic conditions. In vitro and in vivo experiments confirmed that TH-302 NPs could effectively alleviate tumour hypoxia. TH-302 NPs exhibited high bioavailability, effective tumour-targeting ability and satisfactory biosafety. Moreover, the combination of TH-302 NPs with α-PD-1 significantly improved immunotherapeutic efficacy in vivo. Mechanistically, TH-302 NPs reduced the expression of HIF-1α and PD-L1, facilitated the infiltration of CD8+ T cells and increased the levels of TNF-α, IFN-γ, and granzyme B in tumours, thereby enhancing the efficacy of α-PD-1 therapy.

CONCLUSION

TH-302 NPs alleviated the hypoxic tumour microenvironment and enhanced the efficacy of PD-1 blockade. Our results provide evidence that TH-302 NPs can be used as a safe and effective nanodrug for combined immunotherapy in gastric cancer treatment.

A novel hypoxia-associated gene signature for prognosis prediction in head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is the most common malignant tumor of head and neck, which seriously threatens human life and health. However, the mechanism of hypoxia-associated genes (HAGs) in HNSCC remains unelucidated. This study aims to establish a hypoxia-associated gene signature and the nomogram for predicting the prognosis of patients with HNSCC.

METHODS

Previous literature reports provided a list of HAGs. The TCGA database provided genetic and clinical information on HNSCC patients. First, a hypoxia-associated gene risk model was constructed for predicting overall survival (OS) in HNSCC patients and externally validated in four GEO datasets (GSE27020, GSE41613, GSE42743, and GSE117973). Then, immune status and metabolic pathways were analyzed. A nomogram was constructed and assessed the predictive value. Finally, experimental validation of the core genes was performed by qRT-PCR.

RESULTS

A HNSCC prognostic model was constructed based on 8 HAGs. This risk model was validated in four external datasets and exhibited high predictive value in various clinical subgroups. Significant differences in immune cell infiltration levels and metabolic pathways were found between high and low risk subgroups. The nomogram was highly accurate for predicting OS in HNSCC patients.

CONCLUSIONS

The 8 hypoxia-associated gene signature can serve as novel independent prognostic indicators in HNSCC patients. The nomogram combining the risk score and clinical stage enhanced predictive performance in predicting OS compared to the risk model and clinical characteristics alone.

Para-toluenesulfonamide, a novel potent carbonic anhydrase inhibitor, improves hypoxia-induced metastatic breast cancer cell viability and prevents resistance to αPD-1 therapy in triple-negative breast cancer

Overexpression of the hypoxia-induced transmembrane enzyme carbonic anhydrase IX (CA9) has been associated with poor prognosis and chemoresistance in aggressive breast cancer. This study aimed to investigate the involvement of CA9 in the anti-tumor activity of para-toluenesulfonamide (PTS) and elucidate its mechanism of action against breast cancer both in vitro and in vivo. MCF-7 and MDA-MB-231 breast cancer cells were treated with PTS or subjected to hypoxic conditions using cobalt chloride (CoCl2), with acetazolamide serving as a positive control. Additionally, 4T1 breast cancer cell allograft mice were co-treated with PTS and α-programmed cell death 1 (αPD-1) monoclonal antibody for one month. The results demonstrated that PTS effectively reduced cell viability and reversed migration ability in MCF-7 and MDA-MB-231 cells under CoCl2-induced hypoxia. Furthermore, PTS upregulated the expression of apoptosis-related proteins and downregulated CA9, hypoxia-inducible factor-1α (HIF-1α), and vascular endothelial growth factor (VEGF) proteins, possibly through modulation of p38 MAPK and ERK1/2 phosphorylated proteins. In the animal model, PTS100 inhibited tumor growth and lung metastasis in mammary tumor allograft mice, exhibiting synergistic effects when combined with αPD-1 therapy. Collectively, our findings suggest that PTS inhibits breast cancer growth and metastasis through the p38 MAPK/ERK1/2 pathway. Moreover, PTS may have the potential to prevent the development of resistance to αPD-1 therapy in breast cancer.

New insights into RAS in head and neck cancer

RAS genes are known to be dysregulated in cancer for several decades, and substantial effort has been dedicated to develop agents that reduce RAS expression or block RAS activation. The recent introduction of RAS inhibitors for cancer patients highlights the importance of comprehending RAS alterations in head and neck cancer (HNC). In this regard, we examine the published findings on RAS alterations and pathway activations in HNC, and summarize their role in HNC initiation, progression, and metastasis. Specifically, we focus on the intrinsic role of mutated-RAS on tumor cell signaling and its extrinsic role in determining tumor-microenvironment (TME) heterogeneity, including promoting angiogenesis and enhancing immune escape. Lastly, we summarize the intrinsic and extrinsic role of RAS alterations on therapy resistance to outline the potential of targeting RAS using a single agent or in combination with other therapeutic agents for HNC patients with RAS-activated tumors.

An oncolytic virus-delivered TGFβ inhibitor overcomes the immunosuppressive tumor microenvironment

While checkpoint blockade immunotherapies have widespread success, they rely on a responsive immune infiltrate; as such, treatments enhancing immune infiltration and preventing immunosuppression are of critical need. We previously generated αPD-1 resistant variants of the murine HNSCC model MEER. While entirely αPD-1 resistant, these tumors regress after single dose of oncolytic vaccinia virus (VV). We then generated a VV-resistant MEER line to dissect the immunologic features of sensitive and resistant tumors. While treatment of both tumor types induced immune infiltration and IFNγ, we found a defining feature of resistance was elevation of immunosuppressive cytokines like TGFβ, which blunted IFNγ signaling, especially in regulatory T cells. We engineered VV to express a genetically encoded TGFβRII inhibitor. Inhibitor-expressing VV produced regressions in resistant tumor models and showed impressive synergy with checkpoint blockade. Importantly, tumor-specific, viral delivery of TGFβ inhibition had no toxicities associated with systemic TGFβ/TGFβR inhibition. Our data suggest that aside from stimulating immune infiltration, oncolytic viruses are attractive means to deliver agents to limit immunosuppression in cancer.

mRNA-LNP vaccination-based immunotherapy augments CD8+ T cell responses against HPV-positive oropharyngeal cancer

Although mRNA vaccines are known as potent activators of antigen-specific immune responses against infectious diseases, limited understanding of how they drive the functional commitment of CD8+ T cells in tumor microenvironment (TME) and secondary lymphoid organs hinders their broader application in cancer immunotherapy. Here, we systematically evaluated the immunological effects of a lipid nanoparticle (LNP)-encapsulated mRNA vaccine that encodes human papillomavirus E7 protein (HPV mRNA-LNP), a tumor-specific antigen of HPV-positive oropharyngeal squamous cell carcinoma (OPSCC). HPV mRNA-LNP vaccination activated overall and HPV-specific CD8+ T cells, as well as differentially drove the functional commitment of CD8+ T cells through distinct IFN-response and exhaustion trajectories in the spleen and TME, respectively. Combination therapies of HPV mRNA-LNP vaccination with immune checkpoint blockades boosted HPV-specific CD8+ T cells while maintaining their anti-tumor function, thus further promoting tumor regression. Our results showed that the HPV mRNA-LNP vaccination combined with immune checkpoint blockade is a promising approach for immunotherapy of HPV-positive OPSCC.

How to 19F MRI: applications, technique, and getting started

Magnetic resonance imaging (MRI) plays a significant role in the routine imaging workflow, providing both anatomical and functional information. 19F MRI is an evolving imaging modality where instead of 1H, 19F nuclei are excited. As the signal from endogenous 19F in the body is negligible, exogenous 19F signals obtained by 19F radiofrequency coils are exceptionally specific. Highly fluorinated agents targeting particular biological processes (i.e., the presence of immune cells) have been visualised using 19F MRI, highlighting its potential for non-invasive and longitudinal molecular imaging. This article aims to provide both a broad overview of the various applications of 19F MRI, with cancer imaging as a focus, as well as a practical guide to 19F imaging. We will discuss the essential elements of a 19F system and address common pitfalls during acquisition. Last but not least, we will highlight future perspectives that will enhance the role of this modality. While not an exhaustive exploration of all 19F literature, we endeavour to encapsulate the broad themes of the field and introduce the world of 19F molecular imaging to newcomers. 19F MRI bridges several domains, imaging, physics, chemistry, and biology, necessitating multidisciplinary teams to be able to harness this technology effectively. As further technical developments allow for greater sensitivity, we envision that 19F MRI can help unlock insight into biological processes non-invasively and longitudinally.

Genomic and transcriptomic profiling indicates the prognosis significance of mutational signature for TMB-high subtype in Chinese patients with gastric cancer

INTRODUCTION

Gastric cancer (GC)is the third leading cause of cancer-related deaths in China and immunotherapy emerging as a revolutionary treatment for GC recently. Tumor mutational burden (TMB) is a predictive biomarker of immunotherapy in multiple cancers. However, the prognostic significance and subtype of TMB in GC is not fully understood.

OBJECTIVES

This study aims to evaluate the prognostic value of TMB in Chinese GC and further classify TMB-high GC (GCTMB-H) patients combing with mutational signatures.

METHODS

Genomic profiling of 435 cancer-gene panel was performed using 206 GC samples from Chinese people. Actionable genetic alterations were compared across all the samples to generate actionable subtyping. The prognostic value of TMB in Chinese GC was evaluated. Mutational signatures were analyzed on TMB-H subtype to stratify the prognosis of TMB. Transcriptomic analysis was applied to compare the distributed immunocytes among different subtypes.

RESULTS

88.3% (182/206) of GC samples had at least one mutation, while 45.1% (93/206) had at least one somatic copy number alteration (SCNA). 29.6% (61/206) of GC samples were TMB-H, including 13 MSI-H and 48 MSS tumors. According to distinct genetic alteration profiles of 69 actionable genes, we classified GC samples into eight molecular subtypes, including TMB-H, ERBB2 amplified, ATM mutated, BRCA2 mutated, CDKN2A/B deleted, PI3KCA mutated, KRAS mutated, and less-mutated subtype. TMB-H subtype presented a remarkable immune-activated phenotype as determined by transcriptomic analysis that was further validated in the TCGA GC cohort. GCTMB-H patients exhibited significantly better survival (P = 0.047). But Signature 1-high GCTMB-H patients had relatively worse prognosis (P = 0.0209, HR = 2.571) than Signature 1-low GCTMB-H patients from Chinese GC cohort, also validated in TCGA GC cohort, presenting highly activated carbohydrate, fatty acid or lipid metabolism.

CONCLUSION

The Signature 1-high GCTMB-H could be a marker of poor prognosis and is associated with metabolism disorder.

SLC1A5 is a novel biomarker associated with ferroptosis and the tumor microenvironment: a pancancer analysis

Solute carrier family 1 member 5 (SLC1A5) is a member of the solute carrier (SLC) superfamily of transporters and plays an important role in tumors as a key transporter of glutamine into cells. However, the relationship between SLC1A5, which is involved in immune regulation, and immune cell infiltration in the tumor microenvironment has not been elucidated, and the relationship between SLC1A5 and ferroptosis is rarely reported. Therefore, we comprehensively analyzed the expression level of SLC1A5 across cancers and compared it with that in normal tissues. Then, the relationship between SLC1A5 expression and the tumor immune microenvironment was analyzed by single-cell analysis, gene set enrichment analysis (GSEA), and Tumor Immune Estimation Resource (TIMER). Next, the correlations of the SLC1A5 expression level with immunotherapy response, immunomodulator expression, tumor mutation burden (TMB) and microsatellite instability (MSI) were evaluated. Finally, in vitro experiments verified that SLC1A5 participates in ferroptosis of glioma cells to regulate tumor progression. Our results indicated that SLC1A5 is aberrantly expressed in most cancer types and closely associated with prognosis. The GSEA results showed that SLC1A5 is involved in immune activation processes and closely related to the infiltration levels of different immune cells in different cancer types. Upon further investigation, we found that SLC1A5 is a suppressor of ferroptosis in glioma, and SLC1A5 knockdown inhibited the proliferation and migration of glioma cells in vitro. In conclusion, we conducted a pancancer analysis of SLC1A5, demonstrated its role as a prognostic biomarker in cancer patients and explored its potential biological functions.

Radiomic signatures from T2W and DWI MRI are predictive of tumour hypoxia in colorectal liver metastases

BACKGROUND

Tumour hypoxia is a negative predictive and prognostic biomarker in colorectal cancer typically assessed by invasive sampling methods, which suffer from many shortcomings. This retrospective proof-of-principle study explores the potential of MRI-derived imaging markers in predicting tumour hypoxia non-invasively in patients with colorectal liver metastases (CLM).

METHODS

A single-centre cohort of 146 CLMs from 112 patients were segmented on preoperative T2-weighted (T2W) images and diffusion-weighted imaging (DWI). HIF-1 alpha immunohistochemical staining index (high/low) was used as a reference standard. Radiomic features were extracted, and machine learning approaches were implemented to predict the degree of histopathological tumour hypoxia.

RESULTS

Radiomic signatures from DWI b200 (AUC = 0.79, 95% CI 0.61-0.93, p = 0.002) and ADC (AUC = 0.72, 95% CI 0.50-0.90, p = 0.019) were significantly predictive of tumour hypoxia. Morphological T2W TE75 (AUC = 0.64, 95% CI 0.42-0.82, p = 0.092) and functional DWI b0 (AUC = 0.66, 95% CI 0.46-0.84, p = 0.069) and b800 (AUC = 0.64, 95% CI 0.44-0.82, p = 0.071) images also provided predictive information. T2W TE300 (AUC = 0.57, 95% CI 0.33-0.78, p = 0.312) and b = 10 (AUC = 0.53, 95% CI 0.33-0.74, p = 0.415) images were not predictive of tumour hypoxia.

CONCLUSIONS

T2W and DWI sequences encode information predictive of tumour hypoxia. Prospective multicentre studies could help develop and validate robust non-invasive hypoxia-detection algorithms.

CRITICAL RELEVANCE STATEMENT

Hypoxia is a negative prognostic biomarker in colorectal cancer. Hypoxia is usually assessed by invasive sampling methods. This proof-of-principle retrospective study explores the role of AI-based MRI-derived imaging biomarkers in non-invasively predicting tumour hypoxia in patients with colorectal liver metastases (CLM).

Can the apparent transverse relaxation rate (R2*) evaluate the efficacy of concurrent chemoradiotherapy in locally advanced nasopharyngeal carcinoma? a preliminary experience

BACKGROUND

The use of the apparent transverse relaxation rate (R2^*) in nasopharyngeal carcinoma (NPC) has not been previously reported in the literature. The aim of this study was to investigate the role of the R2^* value in evaluating response to concurrent chemoradiotherapy (CCRT) in patients with NPC.

METHODS

Forty-one patients with locoregionally advanced NPC confirmed by pathology were examined by blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) before and after CCRT, and conventional MRI was performed 3 months after the completion of CCRT. All patients were divided into a responding group (RG) and a nonresponding group (NRG), according to MRI findings 3 months after the end of treatment. The R2^* values before (R2*_preT) and after (R2^*_postT) CCRT and the ΔR2^* (ΔR2^*=R2^*_postT - R2^*_preT) were calculated in the tumor.

RESULTS

Among the 41 patients, 26 were in the RG and 15 were in the NRG. There was no statistical difference in the R2^*_preT between RG and NRG (P = 0.307); however, there were significant differences in R2^*_postT and ΔR2^* (P < 0.001). The area under the curve of R2^*_postT and ΔR2^* for predicting the therapeutic response of NPC was 0.897 and 0.954, respectively, with cutoff values of 40.95 and 5.50 Hz, respectively.

CONCLUSION

The R2^* value can be used as a potential imaging indicator to evaluate the therapeutic response of locoregionally advanced NPC.

The role of nanotherapy in head and neck squamous cell carcinoma by targeting tumor microenvironment

Head and neck squamous cell carcinomas (HNSCCs) refers to a group of highly malignant and pathogenically complex tumors. Traditional treatment methods include surgery, radiotherapy, and chemotherapy. However, with advancements in genetics, molecular medicine, and nanotherapy, more effective and safer treatments have been developed. Nanotherapy, in particular, has the potential to be an alternative therapeutic option for HNSCC patients, given its advantageous targeting capabilities, low toxicity and modifiability. Recent research has highlighted the important role of the tumor microenvironment (TME) in the development of HNSCC. The TME is composed of various cellular components, such as fibroblasts, vascular endothelial cells, and immune cells, as well as non-cellular agents such as cytokines, chemokines, growth factors, extracellular matrix (ECM), and extracellular vesicles (EVs). These components greatly influence the prognosis and therapeutic efficacy of HNSCC, making the TME a potential target for treatment using nanotherapy. By regulating angiogenesis, immune response, tumor metastasis and other factors, nanotherapy can potentially alleviate HNSCC symptoms. This review aims to summarize and discuss the application of nanotherapy that targets HNSCC's TME. We highlight the therapeutic value of nanotherapy for HNSCC patients.

Nanoparticle-Mediated Radiotherapy Remodels the Tumor Microenvironment to Enhance Antitumor Efficacy

Radiotherapy (RT) uses ionizing radiation to eradicate localized tumors and, in rare cases, control tumors outside of the irradiated fields via stimulating an antitumor immune response (abscopal effect). However, the therapeutic effect of RT is often limited by inherent physiological barriers of the tumor microenvironment (TME), such as hypoxia, abnormal vasculature, dense extracellular matrix (ECM), and an immunosuppressive TME. Thus, it is critical to develop new RT strategies that can remodel the TME to overcome radio-resistance and immune suppression. In the past decade, high-Z-element nanoparticles have been developed to increase radiotherapeutic indices of localized tumors by reducing X-ray doses and side effects to normal tissues and enhance abscopal effects by activating the TME to elicit systemic antitumor immunity. In this review, the principles of RT and radiosensitization, the mechanisms of radio-resistance and immune suppression, and the use of various nanoparticles to sensitize RT and remodel TMEs for enhanced antitumor efficacy are discussed. The challenges in clinical translation of multifunctional TME-remodeling nanoradiosensitizers are also highlighted.

The effect of opioids on the efficacy of immunotherapy in recurrent/metastatic squamous cell carcinoma of the head and neck

OBJECTIVES

Head and neck squamous cell carcinoma (HNSCC) causes severe pain and opioids, the mainstay of pain management, may have immunomodulatory effects. We evaluated the effect of opioids on immunotherapy efficacy in recurrent/metastatic (R/M) HNSCC patients.

MATERIALS AND METHODS

In a retrospective study of 66 R/M HNSCC patients from 2015 to 2020, opioid dosage, calculated as mean morphine milligram equivalent per day, was assessed on the day of anti-PD-1 monoclonal antibody (mAb) treatment and most recent prior visit. Intratumoral T cells were evaluated by single cell RNAseq and immunohistochemistry prior to treatment. Univariable and multivariable Cox proportional hazards and logistic regression models were used to estimate the association between opioid usage, progression-free survival (PFS), overall survival (OS), disease control rate.

RESULTS

Patients were 79% male, 35% oropharynx, 35% oral cavity, 40% locoregional recurrence, and 56% platinum failure. Higher opioid dosage by continuous variable was significantly associated with lower PFS (p = 0.016) and OS (p < 0.001). In multivariable analysis, including platinum failure status and PD-L1, higher opioids were associated with lower OS. Opioid usage by categorical variable was associated with significantly lower intratumoral CD8+ T cells. Opioid receptor, OPRM1, expression was identified in intratumoral and circulating T cells.

CONCLUSIONS

In our study cohort of anti-PD-1 mAb treatment in R/M HNSCC patients, higher opioids were associated with significantly lower PFS and OS and lower CD8+ T cells in the tumor microenvironment. To our knowledge, this is the first analysis in R/M HNSCC patients and further research into the clinical and biologic effect of opioids is warranted.

Tumor-Associated Fibrosis Impairs the Response to Immunotherapy

Previously, impaired responses to immunotherapy in cancer had been attributed mainly to inherent tumor characteristics (tumor cell intrinsic factors) such as low immunogenicity, (low) mutational burden, weak host immune system, etc. However, mapping the responses of immunotherapeutic regimes in clinical trials for different types of cancer has pointed towards an obvious commonality - that tumors with a rich fibrotic stroma respond poorly or not at all. This has prompted a harder look on tumor cell extrinsic factors such as the surrounding tumor microenvironment (TME), and specifically, the fibrotic stroma as a potential enabler of immunotherapy failure. Indeed, the role of cancer-associated fibrosis in impeding efficacy of immunotherapy is now well-established. In fact, recent studies reveal a complex interconnection between fibrosis and treatment efficacy. Accordingly, in this review we provide a general overview of what a tumor associated fibrotic reaction is and how it interacts with the members of immune system that are frequently seen to be modulated in a failed immunotherapeutic regime.

Prior anti-CTLA-4 therapy impacts molecular characteristics associated with anti-PD-1 response in advanced melanoma

Immune checkpoint inhibitors (ICIs), including CTLA-4- and PD-1-blocking antibodies, can have profound effects on tumor immune cell infiltration that have not been consistent in biopsy series reported to date. Here, we analyze seven molecular datasets of samples from patients with advanced melanoma (N = 514) treated with ICI agents to investigate clinical, genomic, and transcriptomic features of anti-PD-1 response in cutaneous melanoma. We find that prior anti-CTLA-4 therapy is associated with differences in genomic, individual gene, and gene signatures in anti-PD-1 responders. Anti-CTLA-4-experienced melanoma tumors that respond to PD-1 blockade exhibit increased tumor mutational burden, inflammatory signatures, and altered cell cycle processes compared with anti-CTLA-4-naive tumors or anti-CTLA-4-experienced, anti-PD-1-nonresponsive melanoma tumors. We report a harmonized, aggregate resource and suggest that prior CTLA-4 blockade therapy is associated with marked differences in the tumor microenvironment that impact the predictive features of PD-1 blockade therapy response.

Role of the human solute carrier family 14 member 1 gene in hypoxia-induced renal cell carcinoma occurrence and its enlightenment to cancer nursing

BACKGROUND

Hypoxia is considered a critical contributor to renal cell carcinoma progression, including invasion and metastasis. However, the potential mechanisms by which it promotes invasion and metastasis have not yet been clarified. The purpose of this study was to investigate the role and mechanism of hypoxia-induced renal cell carcinoma and provide evidence-based medical proof for improvements to postoperative nursing of renal cell carcinoma patients. A total of 64 patients with renal cell carcinoma were divided into the observation group (nursing based on oxygen administration) and the control group (conventional nursing). Renal function indexes, serum inflammatory factors, and tumor markers were evaluated. The human renal cell carcinoma cell line A498 under hypoxia/normoxia was used as an experimental model in vitro and the biological characteristics and mitochondrial function of the cells were assessed.

RESULTS

Nursing based on oxygen administration decreased the value of renal function indexes, serum inflammatory factors, and tumor markers in renal cell carcinoma patients. Hypoxia was found to induce A498 cell invasion, migration, and the release of inflammatory cytokines, while repressing human solute carrier family 14 member 1 gene expression. Elevated levels of solute carrier family 14 member 1 expression induced mitochondrial reactive oxygen species accumulation, diminished the intracellular adenosine triphosphate level, and destroyed both mitochondrial membrane potential integrity and mitochondrial morphology. Overexpression of the solute carrier family 14 member 1 gene could abolish hypoxia-induced invasion, reduce the migration of A498 cells, inhibit the hypoxia-induced release of inflammatory cytokines, and arrest the cell cycle at the G1/S checkpoint.

CONCLUSIONS

These data reveal that nursing based on oxygen administration can improve the clinical efficacy of renal cell carcinoma therapies, being safe and effective. The results elucidate a mechanism wherein the solute carrier family 14 member 1 gene participates in the occurrence and development of hypoxia-induced renal cell carcinoma in a mitochondria-dependent manner.

Vascular Normalization Was Associated with Colorectal Tumor Regression upon Anti-PD-L1 Combinational Therapy

Anti-PD-L1 therapy exhibits durable efficacy, but only in a small fraction of cancer patients. The immunosuppressive tumor microenvironment (TME) is a crucial obstacle that impedes cancer immunotherapy. Here, we found that anti-PD-L1 therapy coupled with CD4+ T cell depletion induced colorectal tumor regression and vascular normalization, while monotherapy only retarded tumor growth without affecting the tumor vasculature. Moreover, simultaneous PD-L1 blockade and CD4+ T cell depletion eradicated intratumoral PD-L1+ lymphoid and myeloid cell populations, while additively elevating the proportions of CD44+CD69+CD8+, central memory CD44+CD62L+CD8+, and effector memory CD44+CD62L-CD8+ T cells, suggesting a reduction in immunosuppressive cell populations and the activation of CD8+ T cells in the TME. Moreover, anti-PD-L1 therapy reduced the proportions of intratumoral PD-L1+ immune cells and suppressed tumor growth in a CD8+ T cell dependent manner. Together, these results suggest that anti-PD-L1 therapy induces tumor vascular normalization and colorectal tumor regression via CD8+ T cells, which is antagonized by CD4+ T cells. Our findings unveil the positive correlation of tumor regression and vascular normalization in colorectal tumor models upon anti-PD-L1 therapy, providing a potential new strategy to improve its efficacy.

Metabolic programming and immune suppression in the tumor microenvironment

Increased glucose metabolism and uptake are characteristic of many tumors and used clinically to diagnose and monitor cancer progression. In addition to cancer cells, the tumor microenvironment (TME) encompasses a wide range of stromal, innate, and adaptive immune cells. Cooperation and competition between these cell populations supports tumor proliferation, progression, metastasis, and immune evasion. Cellular heterogeneity leads to metabolic heterogeneity because metabolic programs within the tumor are dependent not only on the TME cellular composition but also on cell states, location, and nutrient availability. In addition to driving metabolic plasticity of cancer cells, altered nutrients and signals in the TME can lead to metabolic immune suppression of effector cells and promote regulatory immune cells. Here we discuss how metabolic programming of cells within the TME promotes tumor proliferation, progression, and metastasis. We also discuss how targeting metabolic heterogeneity may offer therapeutic opportunities to overcome immune suppression and augment immunotherapies.

Quantitative Imaging of Hypoxic CAIX-Positive Tumor Areas with Low Immune Cell Infiltration in Syngeneic Mouse Tumor Models

Limited diffusion of oxygen in combination with increased oxygen consumption leads to chronic hypoxia in most solid malignancies. This scarcity of oxygen is known to induce radioresistance and leads to an immunosuppressive microenvironment. Carbonic anhydrase IX (CAIX) is an enzyme functioning as a catalyzer for acid export in hypoxic cells and is an endogenous biomarker for chronic hypoxia. The aim of this study is to develop a radiolabeled antibody that recognizes murine CAIX to visualize chronic hypoxia in syngeneic tumor models and to study the immune cell population in these hypoxic areas. An anti-mCAIX antibody (MSC3) was conjugated to diethylenetriaminepentaacetic acid (DTPA) and radiolabeled with indium-111 (¹¹¹In). CAIX expression on murine tumor cells was determined using flow cytometry, and in vitro affinity of [¹¹¹In]In-MSC3 was analyzed in a competitive binding assay. Ex vivo biodistribution studies were performed to determine in vivo radiotracer distribution. CAIX⁺ tumor fractions were determined by mCAIX microSPECT/CT, and the tumor microenvironment was analyzed using immunohistochemistry and autoradiography. We showed that [¹¹¹In]In-MSC3 binds to CAIX-expressing (CAIX⁺) murine cells in vitro and accumulates in CAIX⁺ areas in vivo. We optimized the use of [¹¹¹In]In-MSC3 for preclinical imaging such that it can be applied in syngeneic mouse models and showed that we can quantitatively distinguish between tumor models with varying CAIX⁺ fractions by ex vivo analyses and in vivo mCAIX microSPECT/CT. Analysis of the tumor microenvironment identified these CAIX⁺ areas as less infiltrated by immune cells. Together these data demonstrate that mCAIX microSPECT/CT is a sensitive technique to visualize hypoxic CAIX⁺ tumor areas that exhibit reduced infiltration of immune cells in syngeneic mouse models. In the future, this technique may enable visualization of CAIX expression before or during hypoxia-targeted or hypoxia-reducing treatments. Thereby, it will help optimize immuno- and radiotherapy efficacy in translationally relevant syngeneic mouse tumor models.

Improving head and neck cancer therapies by immunomodulation of the tumour microenvironment

Targeted immunotherapy has improved patient survival in head and neck squamous cell carcinoma (HNSCC), but less than 20% of patients produce a durable response to these treatments. Thus, new immunotherapies that consider all key players of the complex HNSCC tumour microenvironment (TME) are necessary to further enhance tumour-specific T cell responses in patients. HNSCC is an ideal tumour type in which to evaluate immune and non-immune cell differences because of two distinct TME aetiologies (human papillomavirus (HPV)-positive and HPV-negative disease), multiple anatomic sites for tumour growth, and clear distinctions between patients with locally advanced disease and those with recurrent and/or metastatic disease. Recent technological and scientific advancements have provided a more complete picture of all cellular constituents within this complex TME and have evaluated the interplay of both immune and non-immune cells within HNSCC. Here, we include a comprehensive analysis of the complete ecosystem of the HNSCC TME, performed utilizing data-rich resources such as The Cancer Genome Atlas, and cutting-edge techniques, such as single-cell RNA sequencing, high-dimensional flow cytometry and spatial multispectral imaging, to generate improved treatment strategies for this diverse disease.

Hypoxic microenvironment in cancer: molecular mechanisms and therapeutic interventions

Having a hypoxic microenvironment is a common and salient feature of most solid tumors. Hypoxia has a profound effect on the biological behavior and malignant phenotype of cancer cells, mediates the effects of cancer chemotherapy, radiotherapy, and immunotherapy through complex mechanisms, and is closely associated with poor prognosis in various cancer patients. Accumulating studies have demonstrated that through normalization of the tumor vasculature, nanoparticle carriers and biocarriers can effectively increase the oxygen concentration in the tumor microenvironment, improve drug delivery and the efficacy of radiotherapy. They also increase infiltration of innate and adaptive anti-tumor immune cells to enhance the efficacy of immunotherapy. Furthermore, drugs targeting key genes associated with hypoxia, including hypoxia tracers, hypoxia-activated prodrugs, and drugs targeting hypoxia-inducible factors and downstream targets, can be used for visualization and quantitative analysis of tumor hypoxia and antitumor activity. However, the relationship between hypoxia and cancer is an area of research that requires further exploration. Here, we investigated the potential factors in the development of hypoxia in cancer, changes in signaling pathways that occur in cancer cells to adapt to hypoxic environments, the mechanisms of hypoxia-induced cancer immune tolerance, chemotherapeutic tolerance, and enhanced radiation tolerance, as well as the insights and applications of hypoxia in cancer therapy.

Review of biomarkers for response to immunotherapy in HNSCC microenvironment

Head and neck squamous cell carcinoma are one of the most common types of cancer worldwide. Although a variety of treatment methods such as surgery, radiotherapy, chemotherapy, and targeted therapy are widely used in diagnosing and treating HNSCC, the survival prognosis of patients has not been significantly improved in the past decades. As an emerging treatment approach, immunotherapy has shown exciting therapeutic effects in R/M HNSCC. However, the current screening methods are still insufficient, and there is a significant need for reliable predictive biomarkers for personalized clinical management and new therapeutic strategies. This review summarized the application of immunotherapy in HNSCC, comprehensively analyzed the existing bioinformatic studies on immunotherapy in HNSCC, evaluated the current methods of tumor immune heterogeneity and immunotherapy, and aimed to screen molecular markers with potential predictive significance. Among them, PD-1 has obvious predictive relevance as the target of existing immune drugs. Clonal TMB is a potential biomarker for HNSCC immunotherapy. The other molecules, including IFN-γ, CXCL, CTLA-4, MTAP, SFR4/CPXM1/COL5A1, TILs, CAFs, exosomes, and peripheral blood indicators, may have suggestive significance for tumor immune microenvironment and prognosis of immunotherapy.

Mechanisms of drug resistance to immune checkpoint inhibitors in non-small cell lung cancer

Immune checkpoint inhibitors (ICIs) in the form of anti-CTLA-4 and anti-PD-1/PD-L1 have become the frontier of cancer treatment and successfully prolonged the survival of patients with advanced non-small cell lung cancer (NSCLC). But the efficacy varies among different patient population, and many patients succumb to disease progression after an initial response to ICIs. Current research highlights the heterogeneity of resistance mechanisms and the critical role of tumor microenvironment (TME) in ICIs resistance. In this review, we discussed the mechanisms of ICIs resistance in NSCLC, and proposed strategies to overcome resistance.

Tumour-infiltrating lymphocytes: from prognosis to treatment selection

Tumour-infiltrating lymphocytes (TILs) are considered crucial in anti-tumour immunity. Accordingly, the presence of TILs contains prognostic and predictive value. In 2011, we performed a systematic review and meta-analysis on the prognostic value of TILs across cancer types. Since then, the advent of immune checkpoint blockade (ICB) has renewed interest in the analysis of TILs. In this review, we first describe how our understanding of the prognostic value of TIL has changed over the last decade. New insights on novel TIL subsets are discussed and give a broader view on the prognostic effect of TILs in cancer. Apart from prognostic value, evidence on the predictive significance of TILs in the immune therapy era are discussed, as well as new techniques, such as machine learning that strive to incorporate these predictive capacities within clinical trials.

Hypoxia drives CD39-dependent suppressor function in exhausted T cells to limit antitumor immunity

CD8+ T cells are critical for elimination of cancer cells. Factors within the tumor microenvironment (TME) can drive these cells to a hypofunctional state known as exhaustion. The most terminally exhausted T (tTex) cells are resistant to checkpoint blockade immunotherapy and might instead limit immunotherapeutic efficacy. Here we show that intratumoral CD8+ tTex cells possess transcriptional features of CD4+Foxp3+ regulatory T cells and are similarly capable of directly suppressing T cell proliferation ex vivo. tTex cell suppression requires CD39, which generates immunosuppressive adenosine. Restricted deletion of CD39 in endogenous CD8+ T cells resulted in slowed tumor progression, improved immunotherapy responsiveness and enhanced infiltration of transferred tumor-specific T cells. CD39 is induced on tTex cells by tumor hypoxia, thus mitigation of hypoxia limits tTex suppression. Together, these data suggest tTex cells are an important regulatory population in cancer and strategies to limit their generation, reprogram their immunosuppressive state or remove them from the TME might potentiate immunotherapy.

Multi-omics characterization of a scoring system to quantify hypoxia patterns in patients with head and neck squamous cell carcinoma

BACKGROUND

The 5-year survival rate of patients with head and neck squamous cell carcinoma (HNSCC) remains  < 50%. Hypoxia patterns are a hallmark of HNSCC that are associated with its occurrence and progression. However, the precise role of hypoxia during HNSCC, such as the relationship between hypoxia, tumor immune landscape and cell communication orchestration remains largely unknown. The current study integrated data from bulk and single-cell RNA sequencing analyses to define the relationship between hypoxia and HNSCC.

METHODS

A scoring system named the hypoxia score (HS) was constructed based on hypoxia-related genes (HRGs) expression. The predictive value of HS response for patient outcomes and different treatments was evaluated. Single-cell datasets and cell communication were utilized to rule out cell populations which hypoxia targeted on.

RESULTS

The survival outcomes, immune/Estimate scores, responses to targeted inhibitors, and chemotherapeutic, and immunotherapy responses were distinct between a high HS group and a low HS group (all P < 0.05). Single-cell datasets showed different distributions of HS in immune cell populations (P < 0.05). Furthermore, HLA-DPA1/CD4 axis was identified as a unique interaction between CD4 + T Conv and pDC cells.

CONCLUSIONS

Altogether, the quantification for hypoxia patterns is a potential biomarker for prognosis, individualized chemotherapeutic and immunotherapy strategies. The portrait of cell communication characteristics over the HNSCC ecosystem enhances the understanding of hypoxia patterns in HNSCC.