Dynamics of HMBG1 (High Mobility Group Box 1) during radiochemotherapy correlate with outcome of HNSCC patients

The mechanism of high mobility group box-1 protein and its bidirectional regulation in tumors

High-mobility group box-1 protein (HMGB1) is a nonhistone chromatin-related protein widely found in eukaryotic cells. It is involved in the transcription, replication, and repair of DNA to maintain nuclear homeostasis. It participates in cell growth, differentiation, and signal transduction. Recent studies showed that HMGB1 has a bidirectional regulatory effect on tumors by regulating TLR4/MYD88/NF-κB and RAGE/AMPK/mTOR signaling pathways. On the one hand, it is highly expressed in a variety of tumors, promoting tumor proliferation and invasion, while on the other hand, it induces autophagy and apoptosis of tumor cells and stimulates tumor-infiltrating lymphocytes to produce an anti-tumor immune response. At present, HMGB1 could be used as a target to regulate the drug resistance and prognostication in cancer. Clinical applications of HMGB1 in cancer need further in-depth studies.

Machine Learning-assisted immunophenotyping of peripheral blood identifies innate immune cells as best predictor of response to induction chemo-immunotherapy in head and neck squamous cell carcinoma - knowledge obtained from the CheckRad-CD8 trial

PURPOSE

Individual prediction of treatment response is crucial for personalized treatment in multimodal approaches against head-and-neck squamous cell carcinoma (HNSCC). So far, no reliable predictive parameters for treatment schemes containing immunotherapy have been identified. This study aims to predict treatment response to induction chemo-immunotherapy based on the peripheral blood immune status in patients with locally advanced HNSCC.

METHODS

The peripheral blood immune phenotype was assessed in whole blood samples in patients treated in the phase II CheckRad-CD8 trial as part of the pre-planned translational research program. Blood samples were analyzed by multicolor flow cytometry before (T1) and after (T2) induction chemo-immunotherapy with cisplatin/docetaxel/durvalumab/tremelimumab. Machine Learning techniques were used to predict pathological complete response (pCR) after induction therapy.

RESULTS

The tested classifier methods (LDA, SVM, LR, RF, DT, and XGBoost) allowed a distinct prediction of pCR. Highest accuracy was achieved with a low number of features represented as principal components. Immune parameters obtained from the absolute difference (lT2-T1l) allowed the best prediction of pCR. In general, less than 30 parameters and at most 10 principal components were needed for highly accurate predictions. Across several datasets, cells of the innate immune system such as polymorphonuclear cells, monocytes, and plasmacytoid dendritic cells are most prominent.

CONCLUSIONS

Our analyses imply that alterations of the innate immune cell distribution in the peripheral blood following induction chemo-immuno-therapy is highly predictive for pCR in HNSCC.

Molecular determinants of immunogenic cell death elicited by radiation therapy

Cancer cells undergoing immunogenic cell death (ICD) can initiate adaptive immune responses against dead cell-associated antigens, provided that (1) said antigens are not perfectly covered by central tolerance (antigenicity), (2) cell death occurs along with the emission of immunostimulatory cytokines and damage-associated molecular patterns (DAMPs) that actively engage immune effector mechanisms (adjuvanticity), and (3) the microenvironment of dying cells is permissive for the initiation of adaptive immunity. Finally, ICD-driven immune responses can only operate and exert cytotoxic effector functions if the microenvironment of target cancer cells enables immune cell infiltration and activity. Multiple forms of radiation, including non-ionizing (ultraviolet) and ionizing radiation, elicit bona fide ICD as they increase both the antigenicity and adjuvanticity of dying cancer cells. Here, we review the molecular determinants of ICD as elicited by radiation as we critically discuss strategies to reinforce the immunogenicity of cancer cells succumbing to clinically available radiation strategies.

Role and clinical significance of immunogenic cell death biomarkers in chemoresistance and immunoregulation of head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is one of the most common malignancies in the whole world, with little improvement in the 5-year survival rate due to the occurrence of chemoresistance. With the increasing interests in tumor immune microenvironment, immunogenic cell death (ICD)-induced chemotherapy has shown promising results in enhancing sensitivity to immune checkpoint inhibitors (ICI) and improving the efficiency of tumor immunotherapy. This review summarizes the role of key ICD biomarkers and their underlying molecular mechanisms in HNSCC chemoresistance. The results showed that ICD initiation could significantly improve the survival and prognosis of patients. ICD and its biomarker could also serve as molecular markers for tumor diagnosis and prognosis. Moreover, key components of DAMPs including CALR, HGMB1, and ATP are involved in the regulation of HNSCC chemo-sensitivity, confirming that the key biomarkers of ICD can also be developed into new targets for regulating HNSCC chemoresistance. This review clearly illustrates the theoretical basis for the hypothesis that ICD biomarkers are therapeutic targets involved in HNSCC progression, chemoresistance, and even immune microenvironment regulation. The compilation and investigation may provide new insights into the molecular therapy of HNSCC.

The Receptor for Advanced Glycation Endproducts (RAGE) and Its Ligands S100A8/A9 and High Mobility Group Box Protein 1 (HMGB1) Are Key Regulators of Myeloid-Derived Suppressor Cells

Immunotherapies including checkpoint blockade immunotherapy (CBI) and chimeric antigen receptor T cells (CAR-T) have revolutionized cancer treatment for patients with certain cancers. However, these treatments are not effective for all cancers, and even for those cancers that do respond, not all patients benefit. Most cancer patients have elevated levels of myeloid-derived suppressor cells (MDSCs) that are potent inhibitors of antitumor immunity, and clinical and animal studies have demonstrated that neutralization of MDSCs may restore immune reactivity and enhance CBI and CAR-T immunotherapies. MDSCs are homeostatically regulated in that elimination of mature circulating and intratumoral MDSCs results in increased production of MDSCs from bone marrow progenitor cells. Therefore, targeting MDSC development may provide therapeutic benefit. The pro-inflammatory molecules S100A8/A9 and high mobility group box protein 1 (HMGB1) and their receptor RAGE are strongly associated with the initiation and progression of most cancers. This article summarizes the literature demonstrating that these molecules are integrally involved in the early development, accumulation, and suppressive activity of MDSCs, and postulates that S100A8/A9 and HMGB1 serve as early biomarkers of disease and in conjunction with RAGE are potential targets for reducing MDSC levels and enhancing CBI and CAR-T immunotherapies.

Plasma sICAM-1 correlates with tumor volume before primary radiochemotherapy of head and neck squamous cell carcinoma patients

BACKGROUND

Biomarkers are of major interest to optimize diagnosis, prognosis and to guide treatment in head and neck cancer patients. Especially blood-based biomarkers appear promising as they can be easily collected and repeatedly analyzed during the course of radiochemotherapy.

PATIENTS AND METHODS

At first, for a broad overview, multiple immune markers were evaluated in six plasma samples of three head and neck squamous cell carcinoma (HNSCC) patients at the beginning and the end of radio-chemotherapy. In this pre-selection, the soluble Intercellular Adhesion Molecule 1 (sICAM-1) appeared most promising. Thus, this marker was measured in multiple samples (n = 86) during treatment and follow-up in a cohort of eleven patients and correlated with tumor features and clinical data.

RESULTS

We found a strong correlation between the initial levels of sICAM-1 in the plasma and the gross tumor volumes of the primary tumor and the involved lymph nodes. However, during the course of treatment no systematic dynamics could be identified. Toxicity or infections did not seem to influence sICAM-1 concentrations.

CONCLUSIONS

sICAM-1 appears to reflect the pre-treatment total tumor burden (primary tumor and involved lymph nodes) in head and neck tumor patients. However, it does not seem to be a dynamic marker reflecting response during radiochemotherapy. Thus, if our findings are confirmed in future, sICAM-1 could be used as a staging marker: if high sICAM-1 levels but low tumor burden are found it might be reasonable to intensify staging investigations to rule out further, yet undetected, tumor sites.

Association of Cell Death Markers With Tumor Immune Cell Infiltrates After Chemo-Radiation in Cervical Cancer

Irradiation induces distinct cellular responses such as apoptosis, necroptosis, iron-dependent cell death (a feature of ferroptosis), senescence, and mitotic catastrophe. Several of these outcomes are immunostimulatory and may represent a potential for immunogenic type of cell death (ICD) induced by radiotherapy triggering abscopal effects. The purpose of this study is to determine whether intra-tumoral ICD markers can serve as biomarkers for the prediction of patient's outcomes defined as the metastasis status and survival over a 5-year period. Thirty-eight patients with locally advanced cervical cancer, treated with neoadjuvant chemoradiotherapy using cisplatin were included in this study. Pre-treatment tumor biopsy and post-treatment hysterectomy samples were stained for cell death markers and danger associated molecular patterns (DAMPs): cleaved caspase-3 (apoptosis), phosphorylated mixed lineage kinase domain like pseudokinase (pMLKL; necroptosis), glutathione peroxidase 4 (GPX4; ferroptosis) and 4-hydroxy-2-noneal (4-HNE; ferroptosis), high mobility group box 1 (HMGB1) and calreticulin. Although these markers could not predict the patient's outcome in terms of relapse or survival, many significantly correlated with immune cell infiltration. For instance, inducing ferroptosis post-treatment seems to negatively impact immune cell recruitment. Measuring ICD markers could reflect the impact of treatment on the tumor microenvironment with regard to immune cell recruitment and infiltration.

One Sentence Summary

Cell death readouts during neoadjuvant chemoradiation in cervical cancer.

Radiochemotherapy-induced elevations of plasma HMGB1 levels predict therapeutic responses in cancer patients

High mobility group B1 (HMGB1) is a protein that is released from dying cancer cells in the context of immunogenic cell death (ICD). A recent study performed on patients with head and neck squamous cell carcinomas (HNSCC) reports that a chemoradiotherapy-induced increase in circulating HMGB1 levels predicts favorable outcome, echoing prior studies on neoadjuvant treatment of breast and rectal cancer in which the dynamics of HMGB1 plasma levels also have prognostic value. Hence, a therapy-induced rise in HMGB1 may be interpreted as a clinical sign of ICD and therapeutic response.