Role of interleukin-32 in chronic rhinosinusitis

Impact of interleukin-32 germ-line rs28372698 and intronic rs12934561 polymorphisms on cancer development: A systematic review and meta-analysis

OBJECTIVE

The pro-inflammatory cytokine IL-32 has high susceptibility to develop cancer. But no previous meta-analysis was done to provide firm evidence. This systematic review and meta-analysis was designed to evaluate the association of IL-32 gene polymorphisms (rs28372698 and rs12934561) with cancer.

METHOD

Eligible studies were selected using authentic databases searching from January 2013 to January 2021. Demographic data and genotypic information were extracted and organized from the selected studies. Review Manager (RevMan) version 5.4 was used to perform data analysis and data arrangement for meta-analysis.

RESULTS

A total of seven studies with 3395 patients and 3781 controls were included in this study. IL-32 rs28372698 polymorphism implied that mutant allele (TT) carriers had a significantly higher risk of cancer (OR = 1.43, p = 0.032). Codominant 3, recessive and allele models also showed 1.36-, 1.38- and 1.11-fold increased risk, respectively (p < 0.05). Besides, the Asian population showed a significantly increased risk in codominant 2 (OR = 1.74), codominant 3 (OR = 1.78), recessive (OR = 1.76) and allele model (OR = 1.16). IL-32 rs12934561 showed significantly reduced cancer risk in codominant 1 (OR = 0.66. p = 0.035), codominant 2 (OR = 0.76, p = 0.007), and dominant model (OR = 0.72, p = 0.012). After subgroup analysis, an association of rs12934561 was found in Asians (codominant 1: OR = 0.54, p = 7.28 × 10^-8; codominant 2: OR = 1.40, p = 0.019; codominant 3: OR = 0.76, p = 0.0006; dominant model: OR = 0.64, p = 1.12 × 10^-5; overdominant model: OR = 0.64, p = 3.92 × 10^-7) but not in Caucasians. After stratifying with the control source, a significant (p < 0.05) association of rs28372698 and rs12934561 was found with cancer in population-based controls. No publication bias was found, and the outcome of this meta-analysis was not influenced by any individual study confirmed from sensitivity analysis. Moreover, trial sequential analysis (TSA) established a link between rs28372698 and rs12934561 polymorphisms and cancer.

CONCLUSION

The outcome of this meta-analysis revealed that IL-32 rs28372698 and rs12934561 polymorphisms are associated with cancer. Moreover, the Asian dynasty had a significant association compared to Caucasians.

IL-32 exacerbates adenoid hypertrophy via activating NLRP3-mediated cell pyroptosis, which promotes inflammation

Adenoid hypertrophy (AH) is a common pediatric disease caused by inflammatory stimulation. The pro-inflammatory cytokine IL-32 has been reported to promote airway inflammation and also be involved in the pyroptosis pathway. However, whether IL-32 can contribute to AH by mediating pyroptosis remains to be elucidated. The present study aimed to investigate the role of IL-32 in AH and determine the potential underlying mechanisms. Adenoid tissues were collected from healthy children and children with AH, and the expression of IL-32, NACHT LRR and PYD domains-containing protein 3 (NLRP3) and IL-1β in normal and hypertrophic tissues were measured. Human nasal epithelial cells (HNEpCs) were exposed to a series of IL-32 concentrations. HNEpCs with or without IL-32 silencing were stimulated with lipopolysaccharide (LPS), and cell proliferation, cell apoptosis, gasdermin D (GSDMD) activation, production of inflammatory cytokines and the expression levels of proteins related to the potential mechanisms were evaluated by Cell Counting Kit-8, flow cytometry, immunofluorescence staining, ELISA and western blot assays, respectively. The results showed that IL-32, NLRP3 and IL-1β exhibited higher expression in adenoid tissues with AH compared with normal tissues. In HNEpC cells, treatment with IL-32 (2 and 10 ng/ml) promoted cell proliferation, while 50 ng/ml IL-32 inhibited cell proliferation at 12, 24 and 48 h post-treatment. IL-32 (2, 10 and 50 ng/ml) also resulted in differing degrees of apoptosis, GSDMD activation, release of IL-1β, IL-6 and TNF-α, and increased protein expression levels of NLRP3, cleaved-caspase-1, activated GSDMD, nucleotide-binding oligomerization domain-containing protein (NOD) 1/2 and Toll-like receptor (TLR)4 in a concentration-dependent manner. In addition, compared with the LPS group, IL-32 knockdown significantly inhibited LPS-induced enhancement of cell proliferation, cell apoptosis, GSDMD activation and production of inflammatory cytokines, and reversed the increased protein expression of NLRP3, cleaved-caspase-1, activated GSDMD, NOD1/2 and TLR4. In conclusion, IL-32 may play a role in the progression of AH via promoting inflammation, and the potential mechanism may involve the activation of NLRP3-mediated pyroptosis.

Interleukin-32 in Infection, Inflammation and Cancer Biology

Cytokines are small pleiotropic polypeptids secreted dominantly by the cells of the immune system. These polypeptids are main mediators of innate and acquired immunity, responsible for clonal expansion and differentiation of immune cells, initiation of immune response and enhancing of effector functions of leukocytes. Cytokine-related effects are most studied in the fields of inflammation, immunology, and cancer biology. In this review we discuss one of the most intriguing, recently discovered proinflammatory cytokine, interleukin 32.

Elevated serum interleukin-32 levels in patients with endometriosis: A cross-sectional study

PROBLEM

Recently, interleukin (IL)-32 has been suggested to be involved in the pathogenesis of endometriosis. The aim of this study was to investigate whether serum IL-32 level might be used as a biomarker for diagnosis of endometriosis.

METHOD OF STUDY

We recruited the serum samples of 50 patients with histologically confirmed endometriosis and 35 controls. Enzyme-linked immunosorbent assay was used to analyze the serum IL-32, IL-6, IL-10, tumour necrosis factor (TNF)-α, IL-1β, and CA-125 levels in patients with and without the disease and the diagnostic potentials of the cytokines were assessed using receiver operating characteristic curve and the area under the curve (AUC).

RESULTS

Among evaluated cytokines, only serum IL-32 levels showed significant differences between patients with and without endometriosis (1111.24 ± 149.59 vs 631.10 ± 120.23 ng/mL, P = 0.018, respectively). When the diagnostic power of serum IL-32 was evaluated, the AUC was 0.638 (95% confidence interval (CI): 0.521-0.766, P = 0.031). When serum IL-32 levels were combined with serum CA-125 levels, the AUC was increased to 0.749 (95% CI: 0.640-0.858, P < 0.001) with sensitivity and specificity of 60.0% and 82.9% at cutoff value of 0.640, which led to detect 25 more cases of endometriosis than the use of serum CA 125 with the cutoff value of 35 IU/mL (36/50 vs 11/50, P < 0.001) without sacrificing the specificity of the marker.

CONCLUSION

Serum IL-32 levels are elevated in patients with endometriosis, and with combination of serum CA-125 levels, it may serve as a potential biomarker for endometriosis.

Asian Sand Dust Regulates IL-32 Production in Airway Epithelial Cells: Inhibitory Effect of Glucocorticoids

Purpose

Epidemiologic studies have reported that Asian sand dust (ASD) is associated with chronic inflammatory diseases of the respiratory system. Glucocorticoids (GCs) have potent anti-inflammatory properties. The aims of this study were to evaluate the effects of GCs on ASD-induced interleukin-32 (IL-32) expression and to identify the underlying signaling pathways in airway epithelial cells.

Methods

A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to evaluate cytotoxicity in A549 and human primary nasal epithelial cells. Expression levels of IL-32 messenger RNA and protein were measured by Western blot, real-time polymerase chain reaction, ELISA, and immunofluorescence staining. Signaling pathways were analyzed using specific inhibitors of Akt, MAPK, or NF- κB. The effects of GCs on the expression of ASD-induced IL-32 were confirmed with ex vivo organ cultures of the nasal interior turbinate.

Results

ASD (0–400 ng/mL) had no significant cytotoxic effects in A549 cells and human primary nasal epithelial cells. Expression levels of IL-32 were dose-dependently upregulated by ASD treatment in A549 cells. ASD induced phosphorylation of Akt, MAPK, and NF-κB, whereas GCs and specific inhibitors of Akt, MAPK, and NF-κB downregulated these activations and the expression of IL-32. These findings were further confirmed in human primary nasal epithelial cells and ex vivo organ cultures of the nasal interior turbinate.

Conclusions

GCs have an inhibitory effect on ASD-induced IL-32 expression via the Akt, MAPK, and NF- κB signaling pathways in airway epithelial cells.

Interleukin 32, inflammation and cancer

Interleukin-32 (IL-32) is a novel cytokine involved in inflammation and cancer development. IL-32 gene consists of eight small exons, and IL-32 mRNA has nine alternative spliced isoforms, and was thought to be secreted because it contains an internal signal sequence and lacks a transmembrane region. IL-32 is initially expressed selectively in activated T cells by mitogen and activated NK cells and their expression is strongly augmented by microbes, mitogens, and other cytokines. The IL-32 is induced mainly by pathogens and pro-inflammatory cytokines, but IL-32 is more prominent in immune cells than in non-immune tissues. The IL-32 transcript is expressed in various human tissues and organs such as the spleen, thymus, leukocyte, lung, small intestine, colon, prostate, heart, placenta, liver, muscle, kidney, pancreas, and brain. Cytokines are critical components of cell signaling pathways that are involved in the regulation of cell growth, metabolism, hormone signaling, immune regulation and a variety of other physiological functions. Earlier studies have demonstrated that IL-32 regulates cell growth, metabolism and immune regulation and is therefore involved in the pathologic regulator or protectant of inflammatory diseases. Previous studies defined that IL-32 is upregulated in the patients with several inflammatory diseases, and is induced by inflammatory responses. However, several reports suggested that IL-32 is downregulated in several inflammatory diseases including asthma, HIV infection disease, neuronal diseases, metabolic disorders, experimental colitis and metabolic disorders. IL-32 is also involved in various cancer malignancies including renal cancer, esophageal cancer and hepatocellular carcinoma, lung cancer, gastric cancer, breast cancer, pancreatic cancer, lymphoma, osteosarcoma, breast cancer, colon cancer and thyroid carcinoma. Other studies suggested that IL-32 decreases tumor development including cervical cancer, colon cancer and prostate cancer, melanoma, pancreatic cancer, liver cancer and chronic myeloid leukemia. Nevertheless, review articles that discuss the roles and its mechanism of IL-32 isoforms focusing on the therapeutic approaches have not yet been reported. In this review article, we will discuss recent findings regarding IL-32 in the development of diseases and further discuss therapeutic approaches targeting IL-32. Moreover, we will suggest that IL-32 could be the target of several diseases and the therapeutic agents for targeting IL-32 may have potential beneficial effects for the treatment of inflammatory diseases and cancers. Future research should open new avenues for the design of novel therapeutic approaches targeting IL-32.

IL-32: A Novel Pluripotent Inflammatory Interleukin, towards Gastric Inflammation, Gastric Cancer, and Chronic Rhino Sinusitis

A vast variety of nonstructural proteins have been studied for their key roles and involvement in a number of biological phenomenona. Interleukin-32 is a novel cytokine whose presence has been confirmed in most of the mammals except rodents. The IL-32 gene was identified on human chromosome 16 p13.3. The gene has eight exons and nine splice variants, namely, IL-32α, IL-32β, IL-32γ, IL-32δ, IL-32ε, IL-32ζ, IL-32η, IL-32θ, and IL-32s. It was found to induce the expression of various inflammatory cytokines including TNF-α, IL-6, and IL-1β as well as macrophage inflammatory protein-2 (MIP-2) and has been reported previously to be involved in the pathogenesis and progression of a number of inflammatory disorders, namely, inflammatory bowel disease (IBD), gastric inflammation and cancer, rheumatoid arthritis, and chronic obstructive pulmonary disease (COPD). In the current review, we have highlighted the involvement of IL-32 in gastric cancer, gastric inflammation, and chronic rhinosinusitis. We have also tried to explore various mechanisms suspected to induce the expression of this extraordinary cytokine as well as various mechanisms of action employed by IL-32 during the mediation and progression of the above said problems.

Cytokine Patterns and Endotypes in Acute and Chronic Rhinosinusitis

Since rhinosinusitis is an inflammatory disease, cytokines as key regulators of inflammation play a central role in its pathophysiology. In acute rhinosinusitis, several proinflammatory cytokines of different types have been identified. Initial information about the involvement of the inflammasome in rhinosinusitis has been gained, but this area remains open for more detailed research. Although it has been accepted now that chronic rhinosinusitis (CRS) needs to be differentiated into CRS with and without nasal polyps, it has become clear that this distinction is insufficient to clearly define subgroups with uniform pathophysiology and cytokine patterns. While Th1-cytokines are mostly found in CRSsNP and Th2 cytokines in CRSwNP, there is a substantial overlap, and several other cytokines have also been detected. Attempts to identify CRS endotypes based on cytokines are ongoing but not yet generally accepted. Despite the central role of cytokines in rhinosinusitis, no specific cytokine-targeted therapies are currently available, and only very few studies have specifically addressed the effects of such biologicals in rhinosinusitis.

Significant association between IL-32 gene polymorphisms and susceptibility to endometrial cancer in Chinese Han women

Interleukin-32 (IL-32), a pro-inflammatory chemokine, has been reported to be involved in inflammatory, infectious diseases and even cancers. This study aimed to investigate whether two genetic variants (rs28372698 and rs12934561) of IL-32 were associated with susceptibility to endometrial cancer (EC) in Chinese Han women by a hospital-based study with 272 EC patients and 337 healthy controls. Our results showed that the frequencies of TT genotype (P = 0.012, OR = 2.37, 95 % CI = 1.32-4.28) and T allele (P = 0.026, OR = 1.320, 95 % CI = 1.036-1.681) of rs28372698 in EC patients were significantly higher than controls. Clinical analyses indicated the TT genotype frequency was relevant to high clinical stage and cervical invasion. Furthermore, the frequencies of CC genotype (P = 0.0077, OR = 1.62, 95 % CI = 1.05-2.50) and C allele (P = 0.043, OR = 1.269, 95 % CI = 1.011-1.592) of rs12934561 were also significantly higher in EC patients than controls. Stratification analyses revealed that CC genotype was more frequent in endometrioid adenocarcinoma or EC without parametrial invasion. This study demonstrates that IL-32 gene polymorphisms are significantly associated with increased EC susceptibility in Chinese Han women.

Preliminary characterization of IL32 in basal-like/triple negative compared to other types of breast cell lines and tissues

Background

Triple negative breast cancer (TNBC) and often basal-like cancers are defined as negative for estrogen receptor, progesterone receptor and Her2 gene expression. Over the past few years an incredible amount of data has been generated defining the molecular characteristics of both cancers. The aim of these studies is to better understand the cancers and identify genes and molecular pathways that might be useful as targeted therapies. In an attempt to contribute to the understanding of basal-like/TNBC, we examined the Gene Expression Omnibus (GEO) public datasets in search of genes that might define basal-like/TNBC. The Il32 gene was identified as a candidate.

Findings

Analysis of several GEO datasets showed differential expression of IL32 in patient samples previously designated as basal and/or TNBC compared to normal and luminal breast samples. As validation of the GEO results, RNA and protein expression levels were examined using MCF7 and MDA MB231 cell lines and tissue microarrays (TMAs). IL32 gene expression levels were higher in MDA MB231 compared to MCF7. Analysis of TMAs showed 42% of TNBC tissues and 25% of the non-TNBC were positive for IL32, while non-malignant patient samples and all but one hyperplastic tissue sample demonstrated lower levels of IL32 protein expression.

Conclusion

Data obtained from several publically available GEO datasets showed overexpression of IL32 gene in basal-like/TNBC samples compared to normal and luminal samples. In support of these data, analysis of TMA clinical samples demonstrated a particular pattern of IL32 differential expression. Considered together, these data suggest IL32 is a candidate suitable for further study.