IL-6 in the Ecosystem of Head and Neck Cancer: Possible Therapeutic Perspectives

Interleukin-6 serves as a critical factor in various cancer progression and therapy

Interleukin-6 (IL-6), a pro-inflammatory cytokine, plays a crucial role in host immune defense and acute stress responses. Moreover, it modulates various cellular processes, including proliferation, apoptosis, angiogenesis, and differentiation. These effects are facilitated by various signaling pathways, particularly the signal transducer and activator of transcription 3 (STAT3) and Janus kinase 2 (JAK2). However, excessive IL-6 production and dysregulated signaling are associated with various cancers, promoting tumorigenesis by influencing all cancer hallmarks, such as apoptosis, survival, proliferation, angiogenesis, invasiveness, metastasis, and notably, metabolism. Emerging evidence indicates that selective inhibition of the IL-6 signaling pathway yields therapeutic benefits across diverse malignancies, such as multiple myeloma, prostate, colorectal, renal, ovarian, and lung cancers. Targeting key components of IL-6 signaling, such as IL-6Rs, gp130, STAT3, and JAK via monoclonal antibodies (mAbs) or small molecules, is a heavily researched approach in preclinical cancer studies. The purpose of this study is to offer an overview of the role of IL-6 and its signaling pathway in various cancer types. Furthermore, we discussed current preclinical and clinical studies focusing on targeting IL-6 signaling as a therapeutic strategy for various types of cancer.

The "Heater" of "Cold" Tumors-Blocking IL-6

The resolution of inflammation is not simply the end of the inflammatory response but rather a complex process that involves various cells, inflammatory factors, and specialized proresolving mediators following the occurrence of inflammation. Once inflammation cannot be cleared by the body, malignant tumors may be induced. Among them, IL-6, as an immunosuppressive factor, activates a variety of signal transduction pathways and induces tumorigenesis. Monitoring IL-6 can be used for the diagnosis, efficacy evaluation and prognosis of tumor patients. In terms of treatment, improving the efficacy of targeted and immunotherapy remains a major challenge. Blocking IL-6 and its mediated signaling pathways can regulate the tumor immune microenvironment and enhance immunotherapy responses by activating immune cells. Even transform "cold" tumors that are difficult to respond to immunotherapy into immunogenic "hot" tumors, acting as a "heater" for "cold" tumors, restarting the tumor immune cycle, and reducing immunotherapy-related toxic reactions and drug resistance. In clinical practice, the combined application of IL-6 inhibition with targeted therapy and immunotherapy may produce synergistic results. Nevertheless, additional clinical trials are imperative to further validate the safety and efficacy of this therapeutic approach.

Small protein blockers of human IL-6 receptor alpha inhibit proliferation and migration of cancer cells

BACKGROUND

Interleukin-6 (IL-6) is a multifunctional cytokine that controls the immune response, and its role has been described in the development of autoimmune diseases. Signaling via its cognate IL-6 receptor (IL-6R) complex is critical in tumor progression and, therefore, IL-6R represents an important therapeutic target.

METHODS

An albumin-binding domain-derived highly complex combinatorial library was used to select IL-6R alpha (IL-6Rα)-targeted small protein binders using ribosome display. Large-scale screening of bacterial lysates of individual clones was performed using ELISA, and their IL-6Rα blocking potential was verified by competition ELISA. The binding of proteins to cells was monitored by flow cytometry and confocal microscopy on HEK293T-transfected cells, and inhibition of signaling function was examined using HEK-Blue IL-6 reporter cells. Protein binding kinetics to living cells was measured by LigandTracer, cell proliferation and toxicity by iCELLigence and Incucyte, cell migration by the scratch wound healing assay, and prediction of binding poses using molecular modeling by docking.

RESULTS

We demonstrated a collection of protein variants called NEF ligands, selected from an albumin-binding domain scaffold-derived combinatorial library, and showed their binding specificity to human IL-6Rα and antagonistic effect in HEK-Blue IL-6 reporter cells. The three most promising NEF108, NEF163, and NEF172 variants inhibited cell proliferation of malignant melanoma (G361 and A2058) and pancreatic (PaTu and MiaPaCa) cancer cells, and suppressed migration of malignant melanoma (A2058), pancreatic carcinoma (PaTu), and glioblastoma (GAMG) cells in vitro. The NEF binders also recognized maturation-induced IL-6Rα expression and interfered with IL-6-induced differentiation in primary human B cells.

CONCLUSION

We report on the generation of small protein blockers of human IL-6Rα using directed evolution. NEF proteins represent a promising class of non-toxic anti-tumor agents with migrastatic potential.

Bridging tissue repair and epithelial carcinogenesis: epigenetic memory and field cancerization

The epigenome coordinates spatial-temporal specific gene expression during development and in adulthood, for the maintenance of homeostasis and upon tissue repair. The upheaval of the epigenetic landscape is a key event in the onset of many pathologies including tumours, where epigenetic changes cooperate with genetic aberrations to establish the neoplastic phenotype and to drive cell plasticity during its evolution. DNA methylation, histone modifiers and readers or other chromatin components are indeed often altered in cancers, such as carcinomas that develop in epithelia. Lining the surfaces and the cavities of our body and acting as a barrier from the environment, epithelia are frequently subjected to acute or chronic tissue damages, such as mechanical injuries or inflammatory episodes. These events can activate plasticity mechanisms, with a deep impact on cells' epigenome. Despite being very effective, tissue repair mechanisms are closely associated with tumour onset. Here we review the similarities between tissue repair and carcinogenesis, with a special focus on the epigenetic mechanisms activated by cells during repair and opted by carcinoma cells in multiple epithelia. Moreover, we discuss the recent findings on inflammatory and wound memory in epithelia and describe the epigenetic modifications that characterise them. Finally, as wound memory in epithelial cells promotes carcinogenesis, we highlight how it represents an early step for the establishment of field cancerization.

Serum concentrations of proinflammatory biomarker interleukin-6 (IL-6) as a predictor of postoperative complications after elective colorectal surgery

BACKGROUND

The aim of this prospective study was to evaluate the role of serum IL-6 as a potential predictive biomarker of postoperative complications (POC) in elective colorectal surgery.

METHOD

A total of 115 patients underwent colorectal surgery for malignancy. IL-6 was measured on the first and third postoperative days (POD1, POD3), and C-reactive protein (CRP) was measured on the POD3. POC was analysed in subgroups according to Clavien‒Dindo (CD), antibiotic (ATB) treatment, intensive care unit (ICU) and hospital length of stay. The predictive power of variables for evaluated endpoints was analysed using receiver-operating characteristic (ROC) analysis and described by area under the curve (AUC). ROC analysis was adopted for the identification of optimal cut-offs. Histological analysis was performed to verify IL-6 production by the tumour.

RESULTS

Out of 115 patients who were analysed, 42% had POC. Patients with POC had significantly higher serum levels of IL-6 on POD1 (p < 0.001) and POD3 (p < 0.001). IL-6 early on POD1 as a predictor of antibiotic treatment, ICU stay and hospital stay (AUC 0.818; 0.811; 0.771) did not significantly differ from the AUC of CRP late on POD3 (0.879; 0.838, 0.752). A cut-off IL-6 value of 113 pg/ml on POD1 and 180.5 pg/ml on POD3 in severe complications (CD > 3a) resulted in 75% and 72% sensitivity, 78.6% and 99% specificity, negative predictive value 96.4% and 97% and positive predictive value 29% and 88.9%.

CONCLUSION

The serum level of interleukin-6 can predict severe (CD > 3a) POC early on POD1. On POD3, IL-6 is superior to CRP in terms of high positive predictive power of severe POC. Interestingly, the advantage of IL-6 on POD1 is early prediction of the need for antibiotic treatment, ICU stay and hospital stay, which is comparable to the CRP serum level late on the third POD.

Cancer-associated fibroblasts: Mediators of head and neck tumor microenvironment remodeling

Cancer-associated fibroblasts (CAFs) are involved in critical aspects of head and neck squamous cell carcinoma (HNSCC) pathogenesis, such as the formation of a tumor-permissive extracellular matrix structure, angiogenesis, or immune and metabolic reprogramming of the tumor microenvironment (TME), with implications for metastasis and resistance to radiotherapy and chemotherapy. The pleiotropic effect of CAFs in TME is likely to reflect the heterogeneity and plasticity of their population, with context-dependent effects on carcinogenesis. The specific properties of CAFs provide many targetable molecules that could play an important role in the future therapy of HNSCC. In this review article, we will focus on the role of CAFs in the TME of HNSCC tumors. We will also discuss clinically relevant agents targeting CAFs, their signals, and signaling pathways, which are activated by CAFs in cancer cells, with the potential for repurposing for HNSCC therapy.

Associations between patient-reported late effects and systemic cytokines in long-term survivors of head and neck cancer treated with radiotherapy

PURPOSE

Head and neck cancer (HNC) treatment may lead to late effects and impaired health-related quality of life of survivors. Knowledge on long-term late effects after radiotherapy (RT) and potential underlying biological mechanisms is lacking. We assessed the prevalence of xerostomia, dysphagia, and chronic fatigue (CF) in HNC survivors ≥ 5 years post-RT, and examined associations between pro-inflammatory cytokines and late effects.

METHODS

In a cross-sectional study, 263 HNC survivors treated between 2007 and 2013 were enrolled. They completed validated questionnaires assessing xerostomia and dysphagia (the EORTC QLQ-H&N35), and CF (the Fatigue Questionnaire), and underwent blood sampling and clinical examination. Pro-inflammatory cytokines were analyzed in 262 survivors and 100 healthy age- and gender-matched controls.

RESULTS

Median time since treatment was 8.5 years. The proportions of survivors reporting xerostomia, dysphagia, and CF were 58%, 31%, and 33%, respectively, with a preponderance of females. We found no significant associations between IL-6, IL-8, IP-10, TARC, TNF, or ENA-78 and the three late effects. The odds of having elevated levels of IL-6 and IP-10 were significantly higher in the survivors compared to the controls.

CONCLUSIONS

More than one-third of long-term HNC survivors experienced xerostomia, dysphagia, and CF. Persistent inflammation, with elevated systemic cytokines, was not associated with these late effects, although HNC survivors had higher levels of some cytokines than the controls.

IMPLICATIONS FOR CANCER SURVIVORS

This study provides new knowledge on late effects that can serve as grounds for informing patients with HNC about risk of late effects more than 5 years after RT.

Autophagy modulators influence the content of important signalling molecules in PS-positive extracellular vesicles

Extracellular vesicles (EVs) are important mediators of intercellular communication in the tumour microenvironment. Many studies suggest that cancer cells release higher amounts of EVs exposing phosphatidylserine (PS) at the surface. There are lots of interconnections between EVs biogenesis and autophagy machinery. Modulation of autophagy can probably affect not only the quantity of EVs but also their content, which can deeply influence the resulting pro-tumourigenic or anticancer effect of autophagy modulators. In this study, we found that autophagy modulators autophinib, CPD18, EACC, bafilomycin A1 (BAFA1), 3-hydroxychloroquine (HCQ), rapamycin, NVP-BEZ235, Torin1, and starvation significantly alter the composition of the protein content of phosphatidylserine-positive EVs (PS-EVs) produced by cancer cells. The greatest impact had HCQ, BAFA1, CPD18, and starvation. The most abundant proteins in PS-EVs were proteins typical for extracellular exosomes, cytosol, cytoplasm, and cell surface involved in cell adhesion and angiogenesis. PS-EVs protein content involved mitochondrial proteins and signalling molecules such as SQSTM1 and TGFβ1 pro-protein. Interestingly, PS-EVs contained no commonly determined cytokines, such as IL-6, IL-8, GRO-α, MCP-1, RANTES, and GM-CSF, which indicates that secretion of these cytokines is not predominantly mediated through PS-EVs. Nevertheless, the altered protein content of PS-EVs can still participate in the modulation of the fibroblast metabolism and phenotype as p21 was accumulated in fibroblasts influenced by EVs derived from CPD18-treated FaDu cells. The altered protein content of PS-EVs (data are available via ProteomeXchange with identifier PXD037164) also provides information about the cellular compartments and processes that are affected by the applied autophagy modulators. Video Abstract.

Expression of Selected miRNAs in Normal and Cancer-Associated Fibroblasts and in BxPc3 and MIA PaCa-2 Cell Lines of Pancreatic Ductal Adenocarcinoma

Therapy for pancreatic ductal adenocarcinoma remains challenging, and the chances of a complete cure are very limited. As in other types of cancer, the expression and role of miRNAs in controlling the biological properties of this type of tumor have been extensively studied. A better insight into miRNA biology seems critical to refining diagnostics and improving their therapeutic potential. In this study, we focused on the expression of miR-21, -96, -196a, -210, and -217 in normal fibroblasts, cancer-associated fibroblasts prepared from a ductal adenocarcinoma of the pancreas, and pancreatic carcinoma cell lines. We compared these data with miRNAs in homogenates of paraffin-embedded sections from normal pancreatic tissues. In cancer-associated fibroblasts and cancer cell lines, miRNAs differed significantly from the normal tissue. In detail, miR-21 and -210 were significantly upregulated, while miR-217 was downregulated. Similar transcription profiles were earlier reported in cancer-associated fibroblasts exposed to hypoxia. However, the cells in our study were cultured under normoxic conditions. We also noted a relation to IL-6 production. In conclusion, cultured cancer-associated fibroblasts and carcinoma cells reflect miR-21 and -210 expression similarly to the cancer tissue samples harvested from the patients.

The Role of IL-6 in Cancer Cell Invasiveness and Metastasis-Overview and Therapeutic Opportunities

Interleukin 6 (IL-6) belongs to a broad class of cytokines involved in the regulation of various homeostatic and pathological processes. These activities range from regulating embryonic development, wound healing and ageing, inflammation, and immunity, including COVID-19. In this review, we summarise the role of IL-6 signalling pathways in cancer biology, with particular emphasis on cancer cell invasiveness and metastasis formation. Targeting principal components of IL-6 signalling (e.g., IL-6Rs, gp130, STAT3, NF-κB) is an intensively studied approach in preclinical cancer research. It is of significant translational potential; numerous studies strongly imply the remarkable potential of IL-6 signalling inhibitors, especially in metastasis suppression.

Autoimmunity, cancer and COVID-19 abnormally activate wound healing pathways: critical role of inflammation

Recent evidence indicates that targeting IL-6 provides broad therapeutic approaches to several diseases. In patients with cancer, autoimmune diseases, severe respiratory infections [e.g. coronavirus disease 2019 (COVID-19)] and wound healing, IL-6 plays a critical role in modulating the systemic and local microenvironment. Elevated serum levels of IL-6 interfere with the systemic immune response and are associated with disease progression and prognosis. As already noted, monoclonal antibodies blocking either IL-6 or binding of IL-6 to receptors have been used/tested successfully in the treatment of rheumatoid arthritis, many cancer types, and COVID-19. Therefore, in the present review, we compare the impact of IL-6 and anti-IL-6 therapy to demonstrate common (pathological) features of the studied diseases such as formation of granulation tissue with the presence of myofibroblasts and deposition of new extracellular matrix. We also discuss abnormal activation of other wound-healing-related pathways that have been implicated in autoimmune disorders, cancer or COVID-19.

New-Generation Heterocyclic Bis-Pentamethinium Salts as Potential Cytostatic Drugs with Dual IL-6R and Mitochondria-Targeting Activity

IL-6 signaling is involved in the pathogenesis of a number of serious diseases, including chronic inflammation and cancer. Targeting of IL-6 receptor (IL-6R) by small molecules is therefore an intensively studied strategy in cancer treatment. We describe the design, synthesis, and characteristics of two new bis-pentamethinium salts 5 and 6 (meta and para) bearing indole moieties. Molecular docking studies showed that both compounds have the potential to bind IL-6R (free energy of binding −9.5 and −8.1 kcal/mol). The interaction with IL-6R was confirmed using microscale thermophoresis analyses, which revealed that both compounds had strong affinity for the IL-6R (experimentally determined dissociation constants 26.5 ± 2.5 nM and 304 ± 27.6 nM, respectively). In addition, both compounds were cytotoxic for a broad spectrum of cancer cell lines in micromolar concentrations, most likely due to their accumulation in mitochondria and inhibition of mitochondrial respiration. In summary, the structure motif of bis-pentamethinium salts represents a promising starting point for the design of novel multitargeting compounds with the potential to inhibit IL-6 signaling and simultaneously target mitochondrial metabolism in cancer cells.

The Correlation of Swedish Snus, Nicotine Pouches and Other Tobacco Products with Oral Mucosal Health and Salivary Biomarkers

In society, tobacco products, such as e-cigarettes, and smokeless tobacco products, such as snus and nicotine pouches, are becoming more attractive. There is still a lack of information regarding the effects of these products on the oral mucosa and oral saliva biomarkers. The aim of this study is to evaluate oral mucosa and the presence of inflammatory biomarkers IL-6, IL-1, IL-8, TNF alpha and LRG-1 in saliva. Respondents were divided in four groups based on their tobacco product usage. Oral examination was carried out, saliva samples were taken, and the detection of IL-6, IL-8, IL-1, TNF alpha and LRG-1 levels in saliva was carried out. Out of the tobacco users, 30.8% were snus users, 48.7% were cigarette users and 20.5% were e-cigarette users. The control group was composed of respondents who did not use any tobacco products. E-cigarettes were used more by women, but snus was used more by men. Mucosal changes were seen in the group of snus users, and mucosal changes were only seen in men who had used 5–10 tobacco units per day for 5–10 years. Increased IL-6 levels in saliva were detected in respondents who also experienced mucosal changes. Mucosal changes were white, leathery and localized at the site where snus sachets were placed. Saliva, as an easily available biofluid, could be used as a first tool to detect potentially precancerous signs, but the LRG1 marker cannot be used as a prognostic marker.

Cancer-Associated Fibroblasts Influence the Biological Properties of Malignant Tumours via Paracrine Secretion and Exosome Production

Cancer-associated fibroblasts (CAFs) are an essential component of the tumour microenvironment. They represent a heterogeneous group of cells that are under the control of cancer cells and can reversely influence the cancer cell population. They affect the cancer cell differentiation status, and the migration and formation of metastases. This is achieved through the production of the extracellular matrix and numerous bioactive factors. IL-6 seems to play the central role in the communication of noncancerous and cancer cells in the tumour. This review outlines the role of exosomes in cancer cells and cancer-associated fibroblasts. Available data on the exosomal cargo, which can significantly intensify interactions in the tumour, are summarised. The role of exosomes as mediators of the dialogue between cancer cells and cancer-associated fibroblasts is discussed together with their therapeutic relevance. The functional unity of the paracrine- and exosome-mediated communication of cancer cells with the tumour microenvironment represented by CAFs is worthy of attention.