Effect of eosinophil cationic protein (ECP) on Hodgkin lymphoma cell lines

Activated Eosinophils Predict Longer Progression-Free Survival under Immune Checkpoint Inhibition in Melanoma

Immune checkpoint inhibition (ICI) has yielded remarkable results in prolonging survival of metastatic melanoma patients but only a subset of individuals treated respond to therapy. Success of ICI treatment appears to depend on the number of tumor-infiltrating effector T-cells, which are known to be influenced by activated eosinophils. To verify the co-occurrence of activated eosinophils and T-cells in melanoma, immunofluorescence was performed in 285 primary or metastatic tumor tissue specimens from 118 patients. Moreover, eosinophil counts and activity markers such as eosinophil cationic protein (ECP) and eosinophil peroxidase (EPX) were measured in the serum before therapy start and before the 4th infusion of ICI in 45 metastatic unresected melanoma patients. We observed a positive correlation between increased tumor-infiltrating eosinophils and T-cells associated with delayed melanoma progression. High baseline levels of eosinophil count, serum ECP and EPX were linked to prolonged progression-free survival in metastatic melanoma. Our data provide first indications that activated eosinophils are related to the T-cell-inflamed tumor microenvironment and could be considered as potential future prognostic biomarkers in melanoma.

Eosinophils and melanoma: Implications for immunotherapy

New therapies such as immune checkpoint blockers (ICB) have offered extended survival to patients affected by advanced melanoma. However, ICBs have demonstrated debilitating side effects on the joints, liver, lungs, skin, and gut. Several biomarkers have been identified for their role in predicting which patients better tolerate ICBs. Still, these biomarkers are limited by immunologic and genetic heterogeneity and the complexity of translation into clinical practice. Recent observational studies have suggested eosinophil counts, and serum levels of eosinophil cationic protein are significantly associated with prolonged survival in advanced-stage melanoma. It is likely that eosinophils thereby modulate treatment response through mechanisms yet to be explored. Here, we review the functionality of eosinophils, their oncogenic role in melanoma and discuss how these mechanisms may influence patient response to ICBs and their implications in clinical practice.

Eosinophils as Major Player in Type 2 Inflammation: Autoimmunity and Beyond

Eosinophils are a subset of differentiated granulocytes which circulate in peripheral blood and home in several body tissues. Along with their traditional relevance in helminth immunity and allergy, eosinophils have been progressively attributed important roles in a number of homeostatic and pathologic situations. This review aims at summarizing available evidence about eosinophils functions in homeostasis, infections, allergic and autoimmune disorders, and solid and hematological cancers.Their structural and biological features have been described, along with their physiological behavior. This includes their chemokines, cytokines, granular contents, and extracellular traps. Besides, pathogenic- and eosinophilic-mediated disorders have also been addressed, with the aim of highlighting their role in Th2-driven inflammation. In allergy, eosinophils are implicated in the pathogenesis of atopic dermatitis, allergic rhinitis, and asthma. They are also fundamentally involved in autoimmune disorders such as eosinophilic esophagitis, eosinophilic gastroenteritis, acute and chronic eosinophilic pneumonia, and eosinophilic granulomatosis with polyangiitis. In infections, eosinophils are involved in protection not only from parasites but also from fungi, viruses, and bacteria. In solid cancers, local eosinophilic infiltration is variably associated with an improved or worsened prognosis, depending on the histotype. In hematologic neoplasms, eosinophilia can be the consequence of a dysregulated cytokine production or the result of mutations affecting the myeloid lineage.Recent experimental evidence was thoroughly reviewed, with findings which elicit a complex role for eosinophils, in a tight balance between host defense and tissue damage. Eventually, emerging evidence about eosinophils in COVID-19 infection was also discussed.

Eosinophils in the Tumor Microenvironment

Eosinophils are rare blood-circulating and tissue-infiltrating immune cells studied for decades in the context of allergic diseases and parasitic infections. Eosinophils can secrete a wide array of soluble mediators and effector molecules, with potential immunoregulatory activities in the tumor microenvironment (TME). These findings imply that these cells may play a role in cancer immunity. Despite these cells were known to infiltrate tumors since many years ago, their role in TME is gaining attention only recently. In this chapter, we will review the main biological functions of eosinophils that can be relevant within the TME. We will discuss how these cells may undergo phenotypic changes acquiring pro- or antitumoricidal properties according to the surrounding stimuli. Moreover, we will analyze canonical (i.e., degranulation) and unconventional mechanisms (i.e., DNA traps, exosome secretion) employed by eosinophils in inflammatory contexts, which can be relevant for tumor immune responses. Finally, we will review the available preclinical models that could be employed for the study of the role in vivo of eosinophils in cancer.

Clinical characteristics and prognostic factors in Chinese patients with classical Hodgkin's lymphoma involving extranodal sites: a retrospective single-center

Objectives: To analyze the clinical characteristics and prognostic factors in Chinese patients with classical Hodgkin's lymphoma (cHL) involving extranodal sites. Methods: Clinical features and outcomes of 68 patients diagnosed with cHL involving extranodal sites from April 2003 to November 2017 were analyzed retrospectively. The data was compared with that of 76 cHL patients without extranodal involvement in the same period. Results: (1) Extranodal involvement was common in Chinese cHL patients. The most common sites were lung (44.1%) and bone (33.8%), followed by bone marrow, liver, pericardium, pleura and other sites. (2) With a median follow-up period of 4.58 years, the 5-year overall survival (OS) of 68 patients with extranodal involvement was significantly poorer than that of 76 patients with only nodal involvement (81.4% vs. 92.8%, p = 0.018). (3) In univariate analysis, lymphocytopenia (p = 0.027), elevated lactate dehydrogenase (LDH) (p = 0.026) and involved lymph node region (LNR) ≥4 (p = 0.044) predicted inferior freedom from progression (FFP) with significant difference. Elder age (p = 0.010), elevated LDH (p = 0.013), elevated platelet (p = 0.044), involved LNR ≥ 4 (p = 0.047) were also statistically significant in OS. Extranodal sites and number of extranodal sites showed no significant difference in FFP and OS. Factors with p-value smaller than 0.100 were evaluated in multivariate analysis, turning out that lymphocytopenia was the only independent adverse prognostic factor in FFP (p = 0.039; HR = 2.595) and OS (p = 0.028; HR = 4.993). Conclusion: Extranodal involvement was frequent in Chinese cHL patients, with lung to be the most commonly involved site. Lymphocytopenia was the only independent adverse prognostic factor.

Eosinophil-cationic protein - a novel liquid prognostic biomarker in melanoma

BACKGROUND

The role of eosinophils in cancer is not yet completely understood, but patients with eosinophilia show a trend towards longer survival in several types of cancer, including melanoma. However, eosinophil count at initial diagnosis of metastatic melanoma does not predict survival. Since eosinophil cationic protein (ECP) mediates anticancer effects, such as tissue remodelling and cytotoxic activity, we investigated this marker as an early prognostic marker in metastatic melanoma.

METHODS

Serum of 56 melanoma patients was collected at the time of diagnosis of metastatic disease. ECP levels as measured by ELISA were correlated with overall survival (OS) in patients before systemic therapy with immunotherapy or chemotherapy. Statistical analyses were performed using the Log-Rank (Mantel-Cox) test.

RESULTS

The median OS for patients with high serum ECP above 12.2 ng/ml was 12 months (n = 39), compared to 28 months for patients with ECP below this threshold (n = 17; p = 0.0642). In patients with cutaneous melanoma, excluding patients with uveal and mucosal melanoma, the survival difference was even more striking (p = 0.0393). ECP's effect size on OS was observed independently of the consecutive therapy. ECP levels were not correlated with LDH levels.

CONCLUSION

ECP seems to be a novel prognostic serum marker for the outcome of melanoma patients, which is independent of LDH and easy to perform in clinical practice. The striking negative prognostic value of high ECP level is unanticipated and can guide patient management.

The impacts of pretreatment circulating eosinophils and basophils on prognosis of stage Ⅰ-Ⅲ colorectal cancer

AIM

The effects of circulating eosinophils and basophils on cancer survival are unclear. Here, we aimed to explore the impacts of eosinophils and basophils on prognosis of stage I-III colorectal cancer (CRC) patients.

METHODS

From February 2003 to March 2013, 569 stage I-III CRC patients were enrolled in this retrospective study. The associations between pretreatment circulating eosinophils, basophils and CRC overall survival (OS), disease-free survival (DFS) were investigated. Moreover, the prognostic value of combined eosinophils/basophils and neutrophil to lymphocyte ratio (NLR)/platelet to lymphocyte ratio (PLR) was investigated.

RESULTS

Kaplan-Meier methods showed the associations of eosinophils < 0.095 × 10⁹ /L and shorter OS (P < 0.0001), eosinophils < 0.055 × 10⁹ /L and shorter DFS (P < 0.0001), basophils < 0.015 × 10⁹ /L and shorter OS (P = 0.001), basophils < 0.015 × 10⁹ /L and shorter DFS (P = 0.005). Cox regression model showed that eosinophils < 0.095 × 10⁹ /L (hazard ratio [HR], 1.723; 95% confidence intervals [CI] = 1.177-2.523) and basophils < 0.015 × 10⁹ /L (HR, 1.714; 95% CI = 1.152-2.548) were independent prognostic factors for OS, and eosinophils < 0.055 × 10⁹ /L (HR, 2.309; 95% CI = 1.587-3.361) and basophils < 0.015 × 10⁹ /L (HR, 1.397; 95% CI = 1.003-1.945) were independent prognostic factors for DFS, respectively. The combined eosinophil-PLR (HR, 2.611; 95% CI = 1.328-5.130) and basophil-PLR (HR, 2.520; 95% CI = 1.240-5.123) were the independent prognostic factors for OS. The combined eosinophil-NLR (HR, 2.770; 95% CI = 1.528-5.019) and eosinophil-PLR (HR, 4.788; 95% CI = 2.458-9.329) were the independent prognostic factors for DFS.

CONCLUSION

Pretreatment circulating eosinophils < 0.095 × 10⁹ /L/0.055 × 10⁹ /L and circulating basophils < 0.015 × 10⁹ /L have significant impacts on prognosis of stage I-III CRC patients.

An anergic immune signature in the tumor microenvironment of classical Hodgkin lymphoma is associated with inferior outcome

OBJECTIVE

The classical Hodgkin lymphoma (cHL) tumor microenvironment shows an ongoing inflammatory response consisting of varying degrees of infiltrating eosinophils, mast cells, macrophages, regulatory T lymphocytes (Tregs), and activated lymphocytes surrounding the malignant cells. Herein, different immune signatures are characterized and correlated with treatment outcome.

METHODS

Tumor-infiltrating leukocytes were phenotyped in biopsies from 459 patients with cHL. Time to progression (TTP) (primary progression, relapse, or death from cHL) and overall survival were analyzed using Cox proportional hazards regression.

RESULTS

The leukocyte infiltration in the microenvironment was highly diverse between patients and was categorized in 4 immune signatures (active, anergic, innate, or mixed). A high proportion of Tregs (anergic) resulted in shorter TTP (median 12.9-year follow-up) in age-adjusted analyses (hazard ratio = 1.82; 95% confidence interval 1.05-3-15). Epstein-Barr virus (EBV)-positive cases had higher proportions of macrophages and activated lymphocytes than EBV negative, but neither of those leukocytes predicted prognosis.

CONCLUSIONS

Abundant Tregs (anergic signature) indicate a shorter TTP, particularly in younger patients. This is probably due to a reduced ability of the immune system to attack the tumor cells. Our data warrant further investigation if these suggested immune signatures could predict outcome of immunotherapy such as immune checkpoint inhibitors.

Eosinophils: The unsung heroes in cancer?

Prolonged low-grade inflammation or smoldering inflammation is a hallmark of a cancer. Eosinophils are components of the immune microenvironment that modulates tumor initiation and progression. Although canonically associated with a detrimental role in allergic disorders, these cells can induce a protective immune response against helminthes, viral and bacterial pathogens. Eosinophils are a source of anti-tumorigenic (e.g., TNF-α, granzyme, cationic proteins, and IL-18) and protumorigenic molecules (e.g., pro-angiogenic factors) depending on the milieu. In several neoplasias (e.g., melanoma, gastric, colorectal, oral and prostate cancer) eosinophils play an anti-tumorigenic role, in others (e.g., Hodgkin's lymphoma, cervical carcinoma) have been linked to poor prognosis, whereas in yet others they are apparently innocent bystanders. These seemingly conflicting results suggest that the role of eosinophils and their mediators could be cancer-dependent. The microlocalization (e.g., peritumoral vs intratumoral) of eosinophils could be another important aspect in the initiation/progression of solid and hematological tumors. Increasing evidence in experimental models indicates that activation/recruitment of eosinophils could represent a new therapeutic strategy for certain tumors (e.g., melanoma). Many unanswered questions should be addressed before we understand whether eosinophils are an ally, adversary or neutral bystanders in different types of human cancers.

Effect of eosinophil cationic protein on human oral squamous carcinoma cell viability

The exact function of eosinophils in cancer, particularly in oral squamous cell carcinoma (OSCC), has not yet been elucidated and the possible antitumor effect of these leukocytes is associated with the release of cytotoxic proteins, particularly eosinophil cationic protein (ECP). The aim of this study was to evaluate the effect of ECP on human OSCC lines and to provide novel insights into the role of eosinophils in these tumors. The viability of the SCC-4 and SCC-25 OSCC cell lines was assessed by colorimetric assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The cells were plated into 96-well plates in Dulbecco's modified Eagle's medium/Ham's nutrient mixture F12 supplemented with 10% fetal bovine serum. After 24 h, the indicated concentration of ECP (0-10 µ M) was added to each sample. The plate was read using a microplate reader at a wavelength of 570 nm. The association between variables was estimated by linear regression analysis. There was a significant inverse association between ECP concentrations with SCC-4 (β=0.16, P=0.019) and SCC-25 cell viability (β=0.24, P=0.006). To the best of our knowledge, the present study was the first to investigate the effects of ECP on OSCCs and to demonstrate a significant inverse association between ECP concentrations with SCC-4 and SCC-25 cell viability.

Protein post-translational modification in host defense: the antimicrobial mechanism of action of human eosinophil cationic protein native forms

Knowledge on the contribution of protein glycosylation in host defense antimicrobial peptides is still scarce. We have studied here how the post-translational modification pattern modulates the antimicrobial activity of one of the best characterized leukocyte granule proteins. The human eosinophil cationic protein (ECP), an eosinophil specific granule protein secreted during inflammation and infection, can target a wide variety of pathogens. Previous work in human eosinophil extracts identified several ECP native forms and glycosylation heterogeneity was found to contribute to the protein biological properties. In this study we analyze for the first time the antimicrobial activity of the distinct native proteins purified from healthy donor blood. Low and heavy molecular weight forms were tested on Escherichia coli cell cultures and compared with the recombinant non-glycosylated protein. Further analysis on model membranes provided an insight towards an understanding of the protein behavior at the cytoplasmic membrane level. The results highlight the significant reduction in protein toxicity and bacteria agglutination activity for heavy glycosylated fractions. Notwithstanding, the lower glycosylated fraction mostly retains the lipopolysaccharide binding affinity together with the cytoplasmic membrane depolarization and membrane leakage activities. From structural analysis we propose that heavy glycosylation interferes with the protein self-aggregation, hindering the cell agglutination and membrane disruption processes. The results suggest the contribution of post-translational modifications to the antimicrobial role of ECP in host defense.

Eosinophilia in routine blood samples as a biomarker for solid tumor development - A study based on the Copenhagen Primary Care Differential Count (CopDiff) Database

BACKGROUND

Eosinophilia may represent an early paraclinical sign of malignant disease and a host anti-tumor effect. The association between eosinophilia and the development of solid tumors has never before been examined in an epidemiological setting. The aim of the present study was to investigate eosinophilia in routine blood samples as a potential biomarker of solid tumor development in a prospective design.

MATERIAL AND METHODS

From the Copenhagen Primary Care Differential Count (CopDiff) Database, we identified 356 196 individuals with at least one differential cell count (DIFF) encompassing the eosinophil count during 2000-2007. From these, one DIFF was randomly chosen and categorized according to no (< 0.5 × 10(9)/l), mild (≥ 0.5-1.0 × 10(9)/l) or severe (≥ 1.0 × 10(9)/l) eosinophilia. From the Danish Civil Registration System and the Danish Cancer Registry we ascertained all-cause death and solid tumors within the first three years following the DIFF. Using multivariable logistic regression, odds ratios (OR) were calculated and adjusted for previous eosinophilia, sex, age, year, month, C-reactive protein, previous cancer and Charlson's Comorbidity Index.

RESULTS

The risk of bladder cancer was increased with mild eosinophilia [OR 1.93 (CI 1.29-2.89), p = 0.0013]. No associations with eosinophilia were observed for the remaining solid cancers.

CONCLUSION

We demonstrate that eosinophilia in routine blood samples associates with an increased risk of bladder cancer. Our data emphasize that additional preclinical studies are needed in order to shed further light on the role of eosinophils in carcinogenesis, where it is still unknown whether the cells contribute to tumor immune surveillance or neoplastic evolution.

Eosinophilia in routine blood samples and the subsequent risk of hematological malignancies and death

Eosinophilia may represent an early paraclinical sign of hematological malignant disease, but no reports exist on its predictive value for hematological malignancies. From the Copenhagen Primary Care Differential Count (CopDiff) Database, we identified 356,196 individuals with at least one differential cell count (DIFF) encompassing the eosinophil count during 2000-2007. From these, one DIFF was randomly chosen and categorized according to no (<0.5 × 10(9) /L), mild (≥ 0.5-1.0 × 10(9) /L) or severe (≥ 1.0 × 10(9) /L) eosinophilia. From the Danish Cancer Registry and the Danish Civil Registration System, we ascertained hematological malignancies and death within 3 years following the DIFF. Using multivariable logistic regression odds ratios (ORs) were calculated and adjusted for previous eosinophilia in a DIFF, sex, age, year, month, C-reactive protein, previous cancer, and comorbidity. ORs for developing Hodgkin's lymphoma (HL) was significantly increased in individuals exhibiting severe eosinophilia, OR = 9.09 (C.I. 2.77-29.84), P = 0.0003. The association with classical myeloproliferative neoplasms (cMPNs) showed an increasing risk with OR = 1.65 (1.04-2.61) P = 0.0322 and OR = 3.87 (1.67-8.96) P = 0.0016 for mild and severe eosinophilia. Eosinophilia was in a similar fashion associated with chronic lymphatic leukemia (CLL), OR = 2.57 (1.50-4.43), P = 0.0006 and OR = 5.00 (1.57-15.94), P = 0.0065, and all-cause death, OR of 1.16 (1.09-1.24), P < 0.0001 and 1.60 (1.35-1.91), P < 0.0001. We confirm associations between eosinophilia and HL and cMPNs, and in addition for the first time demonstrate a dose-dependent association between eosinophilia and CLL as well as death. Unexplained eosinophilia should prompt clinicians to consider conditions where early diagnosis may improve prognosis.

Asparagine-linked glycans determine the cytotoxic capacity of eosinophil cationic protein (ECP)

Eosinophil cationic protein (ECP) is a toxic, granule-stored protein of the eosinophil granulocyte. It is a heterogeneous protein; molecular weights can differ from 15 to 22 kDa, due to glycosylations. We purified high molecular weight ECP from blood donors with the ECP434GG (rs2073342) genotype, with the aim of examining whether removal of carbohydrates could enhance the cytotoxic capacity. The cytotoxic activity of the ECP pools was tested against the NCI-H69 cell line, before and after enzymatic deglycosylation. ECP was also analysed by SELDI-TOF MS to monitor the changes in molecular mass after deglycosylation. Five high molecular weight pools of ECP (HMW-ECP I-V) with decreasing degrees of glycosylation were tested at concentrations ranging from 0.02 to 0.6 μM. The activity ranged from EC50 of >0.6 μM to 0.04 μM; HMW-ECP II had the lowest activity and HMW-ECP V the highest. After deglycosylation with N-glycosidase F, pools HMW-ECP I-III were reduced to the same molecular weight of 15.78 kDa and acquired potent cytotoxic activities. HMW-ECP IV and V with molecular species at 16.3 and 16.1 kDa were highly cytotoxic as such and were only partially deglycosylated, with slight enhancement of the toxic properties. The results suggest the presence of several HMW-ECP molecular species with differences in their post-translational modifications and cytotoxic properties. We conclude that a fraction of native ECP is stored in a non-cytotoxic form, which can be converted into a cytotoxic form by N-deglycosylation, whereas another fraction is stored as a highly cytotoxic form carrying different post-translational modifications.

Eosinophil cationic protein: overview of biological and genetic features

The eosinophil cationic protein (ECP) is a small polypeptide that originates from activated eosinophil granulocytes. A wide range of stimuli has been shown to induce the secretion of ECP. The gene that encodes the human ECP is located on chromosome 14, and the protein shares the overall three-dimensional structure and the RNase active-site residues with other proteins in the RNase A superfamily. Several single-nucleotide polymorphisms in the human ECP gene have been currently described. ECP has many biological functions, including an immunoregulatory function, the regulation of fibroblast activity, and the induction of mucus secretion in the airway. Additionally, the protein is a potent cytotoxic molecule and has the capacity to kill mammalian and nonmammalian cells. The purpose of this article was to review the known biological and genetic characteristics of ECP that contribute to the understanding of this protein's role in the development and progression of a wide variety of diseases.