NKP30-B7-H6 Interaction Aggravates Hepatocyte Damage through Up-Regulation of Interleukin-32 Expression in Hepatitis B Virus-Related Acute-On-Chronic Liver Failure

Pan-cancer analysis reveals IL32 is a potential prognostic and immunotherapeutic biomarker in cancer

Interleukin 32 (IL32) is a pro-inflammatory cytokine that plays a key role in promoting sterile inflammation by modulating immune responses. However, the role of IL32 in various cancers remains unclear. This research aimed to investigate the correlation between IL32 expression and immunity and visualize its prognostic landscape in pan-cancer. We investigated gene expression, genomic alterations, and survival analysis of IL32 in pan-cancer in numerous databases including TCGA, GTEx, cBioPortal, and GDC databases. Tumor immune cell infiltration was assessed using the CIBERSORT computational method as well as the ESTIMATE method to analyze the correlation of IL32 expression with stromal and immune components. Protein-protein interaction analysis was performed in the STRING and GeneMANIA databases, and gene function enrichment was performed by GO set enrichment analysis. Tumor tissues had higher IL32 expression levels than normal tissues. Elevated IL32 expression was associated with poor OS and prognosis. In addition, tumor stemness, TMB, MSI, and immune checkpoint genes were also associated with IL32 expression. Correlations were observed between IL32 expression and B cell, CD4T cell, CD8T cell, neutrophil, macrophage, and DC infiltration in multiple cancers. GO enrichment analysis showed that IL32 expression was associated with cancer pathways, cytokine-receptor interactions, and NOD-like receptor signaling pathways. These findings suggest that IL32 may serve as a biomarker of cancer immune infiltration and poor prognosis, providing new therapeutic targets for cancer treatment.

Role of interleukin‑32 in cancer progression (Review)

Interleukin (IL)-32 is induced by pro-inflammatory cytokines and promotes the release of inflammatory cytokines. Therefore, it can promote inflammatory responses. The present review article summarized the role of the receptors required for IL-32 action, the biological function of IL-32 and its mechanism of action in tumors. Moreover, it assessed the significance of aberrant IL-32 expression in associated diseases and analyzed the effects of IL-32 on four key types of cancer: Colorectal, gastric, breast and lung. However, the mechanism of action of IL-32 needs to be further demonstrated by assessing the role of this cytokine in cancer to elucidate novel and reliable targets for future cancer treatments.

A Critical Overview of Interleukin 32 in Leishmaniases

Interleukin-32 (IL-32) has several immune regulatory properties, which have driven its investigation in the context of various diseases. IL-32 expression is reported to be induced in the lesions of patients with American tegumentary leishmaniasis (ATL) by the New World Leishmania spp. that are responsible for causing ATL and visceral leishmaniasis (VL). IL-32 expression may elevate the inflammatory process through the induction of pro-inflammatory cytokines and also via mechanisms directed to kill the parasites. The genetic variants of IL-32 might be associated with the resistance or susceptibility to ATL, while different isoforms of IL-32 could be associated with distinct T helper lymphocyte profiles. IL-32 also determines the transcriptional profile in the bone marrow progenitor cells to mediate the trained immunity induced by β-glucan and BCG, thereby contributing to the resistance against Leishmania. IL-32γ is essential for the vitamin D-dependent microbicidal pathway for parasite control. In this context, the present review report briefly discusses the data retrieved from the studies conducted on IL-32 in leishmaniasis in humans and mice to highlight the current challenges to understanding the role of IL-32 in leishmaniasis.

Positive staining of the immunoligand B7-H6 in abnormal/transformed keratinocytes consistently accompanies the progression of cervical cancer

Background

B7-H6 has been revealed as an endogenous immunoligand expressed in a variety of tumors, but not expressed in healthy tissues. Heretofore, no studies have been reported describing B7-H6 in women with cervical cancer. To investigate this question, our present study was conducted.

Results

This retrospective study comprised a total of 62 paraffinized cervical biopsies, which were distributed in five groups: low-grade squamous intraepithelial lesions (LSIL), high-grade squamous intraepithelial lesions (HSIL), squamous cervical carcinoma (SCC), uterine cervical adenocarcinoma (UCAC), and a group of cervicitis (as a control for non-abnormal/non-transformed cells). Cervical sections were stained by immunohistochemistry to explore the expression of B7-H6, which was reported according to the immunoreactive score (IRS) system. We observed a complete lack of B7-H6 in LSIL abnormal epithelial cells. Interestingly, B7-H6 began to be seen in HSIL abnormal epithelial cells; more than half of this group had B7-H6 positive cells, with staining characterized by a cytoplasmic and membranous pattern. B7-H6 in the SCC group was also seen in the majority of the sections, showing the same cytoplasmic and membranous pattern. Strong evidence of B7-H6 was notably found in UCAC tumor columnar cells (in 100% of the specimens, also with cytoplasmic and membranous pattern). Moreover, consistent B7-H6 staining was observed in infiltrating plasma cells in all groups.

Conclusions

B7-H6 IRS positively correlated with disease stage in the development of cervical cancer; additionally, B7-H6 scores were found to be even higher in the more aggressive uterine cervical adenocarcinoma, suggesting a possible future therapeutic target for this cancer type.

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.

Immunological role and underlying mechanisms of B7-H6 in tumorigenesis

B7 homolog 6 (B7-H6) has been identified as involved in tumorigenesis. Elucidating its role and potential mechanism of action is essential for understanding tumorigenesis and the potential development of an effective clinical strategy. Abnormal overexpression of B7-H6 in various types of tumors was reported to be linked with poor prognosis. B7-H6 suppresses the initiation of the "caspase cascade" and induces anti-apoptosis by STAT3 pathway activation to provoke tumorigenesis. B7-H6 facilitates tumor proliferation and cell cycle progression by regulating apoptosis suppressors. B7-H6 induces cellular cytotoxicity, secretion of TNF-α and IFN-γ and B7-H6-specific BiTE triggers T cells to accelerate tumorigenesis. B7-H6 induces abnormal immunological progression by HER2-scFv mediated ADCC and NKp30 immune escape to promote tumorigenesis. B7-H6 promotes tumorigenesis via apoptosis inhibition, proliferation and immunological progression. B7-H6 may a valuable potential biomarker and therapeutic strategy for diagnostics, prognostics and treatment in cancer.

Deficient Natural Killer Cell NKp30-Mediated Function and Altered NCR3 Splice Variants in Hepatocellular Carcinoma

The activating natural cytotoxicity receptor NKp30 is critical for natural killer (NK) cell function and tumor immune surveillance. The natural cytotoxicity receptor-3 (NCR3) gene is transcribed into several splice variants whose physiological relevance is still incompletely understood. In this study, we investigated the role of NKp30 and its major ligand B7 homolog 6 (B7-H6) in patients with hepatocellular carcinoma (HCC). Peripheral blood NK cell phenotype was skewed toward a defective/exhausted immune profile with decreased frequencies of cells expressing NKp30 and natural killer group 2, member D and an increased proportion of cells expressing T-cell immunoglobulin and mucin-domain containing-3. Moreover, NKp30-positive NK cells had a reduced expression of NCR3 immunostimulatory splice variants and an increased expression of the inhibitory variant in patients with advanced tumor, resulting in deficient NKp30-mediated functionality. Tumor-infiltrating lymphocytes showed a prevalent inhibitory NKp30 isoform profile, consistent with decreased NKp30-mediated function. Of note, there were significant differences in the cytokine milieu between the neoplastic and the surrounding non-neoplastic tissue, which may have further influenced NKp30 function. Exposure of NK cells to B7-H6-expressing HCC cells significantly down-modulated NKp30, that was prevented by small interfering RNA-mediated knockdown, suggesting a role for this ligand in inhibiting NKp30-mediated responses. Interestingly, B7-H6 expression was reduced in HCC tissue and simultaneously augmented as a soluble form in HCC patients, particularly those with advanced staging or larger nodule size. Conclusion: These findings provide evidence in support of a role of NKp30 and its major ligand in HCC development and evolution.

B7-H6 expression in human hepatocellular carcinoma and its clinical significance [corrected]

Background

Recent studies have suggested that B7-H6, a new member of the B7 family of ligands, not only is a crucial regulator of NK cell-mediated immune responses but also has important clinical implications due to its abnormal expression in many human cancers. We have previously reported that higher B7-H6 expression levels in ovarian cancer tissues are positively correlated with tumor metastasis and cancer progression. To date, the expression of B7-H6 in human hepatocellular carcinoma (HCC) and the clinical significance of B7-H6 expression still remain elusive.

Methods

In the present study, the expression level of B7-H6 was examined in both HCC tissues and HCC cell lines (HepG2 and SMMC-7721). And the clinical significance of B7-H6 was analyzed as well.

Results

Our results revealed that B7-H6 was expressed abnormally in HCC tissues, which was greatly related to tumor size. The TCGA data also showed that the B7-H6 mRNA expression level was significantly negatively correlated with the survival of HCC patients. Next, to investigate the functions of B7-H6 in HCC, we successfully constructed B7-H6 knockdown expression human HCC cell lines using the RNA interference technology. Our studies showed that reduced expression of B7-H6 in HepG2 and SMMC-7721 cells significantly attenuated cell proliferation as well as cell migration and invasion. Besides, depletion of B7-H6 greatly induced cell cycle arrest at G1 phase. And also B7-H6 knockdown in HCC cell lines dramatically decreased the C-myc, C-fos and Cyclin-D1 expression.

Conclusions

Our present findings suggested that B7-H6 played an important role in oncogenesis of HCC on cellular level, and B7-H6 could be employed to develop immunotherapeutic approaches targeting this malignancy.

Development of unique cytotoxic chimeric antigen receptors based on human scFv targeting B7H6

As a stress-inducible natural killer (NK) cell ligand, B7H6 plays a role in innate tumor immunosurveillance and is a fairly tumor selective marker expressed on a variety of solid and hematologic cancer cells. Here, we describe the isolation and characterization of a new family of single chain fragment variable (scFv) molecules targeting the human B7H6 ligand. Through directed evolution of a yeast surface displayed non-immune human-derived scFv library, eight candidates comprising a single family of clones differing by up to four amino acid mutations and exhibiting nM avidities for soluble B7H6-Ig were isolated. A representative clone re-formatted as an scFv-CH1-Fc molecule demonstrated specific binding to both B7H6-Ig and native membrane-bound B7H6 on tumor cell lines with a binding avidity comparable to the previously characterized B7H6-targeting antibody, TZ47. Furthermore, these clones recognized an epitope distinct from that of TZ47 and the natural NK cell ligand NKp30, and demonstrated specific activity against B7H6-expressing tumor cells when expressed as a chimeric antigen receptor (CAR) in T cells.

Characterization of B7H6, an endogenous ligand for the NK cell activating receptor NKp30, reveals the identity of two different soluble isoforms during normal human pregnancy

B7H6, an endogenous ligand expressed on tumor cell surfaces, triggers NKp30-mediated activation of human NK cells. In contrast, the release of soluble B7H6 has been proposed as a novel mechanism by which tumors might evade NK cell-mediated recognition. Since NK cells are critical for the maintenance of early pregnancy, it is not illogical that soluble B7H6 might also be an important factor in directing NK cell activity during normal pregnancy. Thus, this study was focused on the characterization of soluble B7H6 during the development of normal pregnancy. Serum samples were obtained from healthy pregnant women who were experiencing their second pregnancies (n=36). Additionally, 17 of these pregnant participants were longitudinally studied for the presence of B7H6 during their second and third trimesters. Age-matched healthy non-pregnant women served as controls (n=30). The presence of soluble B7H6 was revealed by Western blotting. A further characterization was performed using an immunoproteomic approach based on 2DE-Western blotting combined with MALDI-MS. The results show that sera from all pregnant women were characterized by the presence of two novel isoforms of B7H6, both with lower MW than the reported of 51kDa. These isoforms were either a heavy (∼37kDa) or a light isoform (∼30kDa) and were mutually exclusive. N-glycosylation did not completely explain the different molecular weights exhibited by the two isoforms, as was demonstrated by enzymatic deglycosylation with PNGase F. The confirmation of the identity and molecular mass of each isoform indicates that B7H6, while maintaining the C- and N-termini, is most likely released during pregnancy by a mechanism distinct from proteolytic cleavage. We found that both isoforms, but mainly the heavier B7H6, were released via exosomes; and that the lighter isoform was also released in an exosome-free manner that was not observed in the heavy isoform samples. In conclusion, we find that soluble B7H6 is constitutively expressed during pregnancy and that, moreover, the soluble B7H6 is present in two new isoforms, which are released by exosomal and exosome-free mechanisms.

Immunoregulatory Role of NK Cells in Tissue Inflammation and Regeneration

NK cells represent an important first line of defense against viral infection and cancer and are also involved in tissue homeostasis. Studies of NK cell activation in the last decade have revealed that they are able to respond to the inflammatory stimuli evoked by tissue damage and contribute to both progression and resolution of diseases. Exacerbation of the inflammatory response through interactions between immune effector cells facilitates the progression of non-alcoholic fatty liver disease (NAFLD) into steatosis, cirrhosis, and hepatocellular carcinoma (HCC). When hepatic damage is incurred, macrophage activation is crucial for initiating cross talk with neighboring cells present in the liver, including hepatocytes and NK cells, and the importance of this interaction in shaping the immune response in liver disease is increasingly recognized. Inflicted structural damage can be in part regenerated via the process of self-limiting fibrosis, though persistent hepatic damage will lead to chronic fibrosis and loss of tissue organization and function. The cytotoxic activity of NK cells plays an important role in inducing hepatic stellate cell apoptosis and thus curtailing the progression of fibrosis. Alternatively, in some diseases, such as HCC, NK cells may become dysregulated, promoting an immunosuppressive state where tumors are able to escape immune surveillance. This review describes the current understanding of the contributions of NK cells to tissue inflammation and metabolic liver diseases and the ongoing effort to develop therapeutics that target the immunoregulatory function of NK cells.

Cytokines and microbicidal molecules regulated by IL-32 in THP-1-derived human macrophages infected with New World Leishmania species

Background

Interleukin-32 (IL-32) is expressed in lesions of patients with American Tegumentary Leishmaniasis (ATL), but its precise role in the disease remains unknown.

Methodology/Principal findings

In the present study, silencing and overexpression of IL-32 was performed in THP-1-derived macrophages infected with Leishmania (Viannia) braziliensis or L. (Leishmania) amazonensis to investigate the role of IL-32 in infection. We report that Leishmania species induces IL-32γ, and show that intracellular IL-32γ protein production is dependent on endogenous TNFα. Silencing or overexpression of IL-32 demonstrated that this cytokine is closely related to TNFα and IL-8. Remarkably, the infection index was augmented in the absence of IL-32 and decreased in cells overexpressing this cytokine. Mechanistically, these effects can be explained by nitric oxide cathelicidin and β-defensin 2 production regulated by IL-32.

Conclusions

Thus, endogenous IL-32 is a crucial cytokine involved in the host defense against Leishmania parasites.

Leishmania (V.) braziliensis and L. (L.) amazonensis are protozoa that infect macrophages and cause cutaneous and mucosal leishmaniasis. Here we showed that both Leishmania species induce the production of IL-32γ in human macrophages. This intracellular and pro-inflammatory cytokine mediates the production of cytokines, especially TNFα and IL-8, in Leishmania-infected macrophages. Differential effects of IL-32γ on TNFα, IL-10 and IL-1Ra production after infection with distinct Leishmania species were detected, consistent with the concept that IL-32γ can differently influence the outcome of inflammatory process in leishmaniasis lesions. Moreover, IL-32γ upregulates microbicidal molecules, antimicrobial peptides, as well as NO, which are known as important factors in parasite control. These results underscore IL-32γ as a crucial cytokine to host defense against leishmaniasis.

The mucin MUC1 modulates the tumor immunological microenvironment through engagement of the lectin Siglec-9

Siglec-9 is a sialic acid binding lectin predominantly expressed on myeloid cells. Aberrant glycosylation occurs in essentially all types of cancers resulting in increased sialylation. Thus when MUC1 is expressed on cancer cells it is decorated by multiple short, sialylated O-linked glycans (MUC1-ST). Here we show that this cancer-specific MUC1 glycoform could, through the engagement of Siglec-9, educate myeloid cells to release factors associated with tumor microenvironment determination and disease progression. Moreover MUC1-ST induced macrophages to display a TAM-like phenotype with increased expression of PD-L1. MUC1-ST binding to Siglec-9 did not activate SHP-1/2 but surprisingly induced calcium flux leading to MEK-ERK activation. This work defines a critical role for aberrantly glycosylated MUC1 and identifies an activating pathway following Siglec-9 engagement.

Natural Killer Cells and Liver Fibrosis

In the 40 years since the discovery of natural killer (NK) cells, it has been well established that these innate lymphocytes are important for early and effective immune responses against transformed cells and infections with different pathogens. In addition to these classical functions of NK cells, we now know that they are part of a larger family of innate lymphoid cells and that they can even mediate memory-like responses. Additionally, tissue-resident NK cells with distinct phenotypical and functional characteristics have been identified. Here, we focus on the phenotype of different NK cell subpopulations that can be found in the liver and summarize the current knowledge about the functional role of these cells with a special emphasis on liver fibrosis. NK cell cytotoxicity can contribute to liver damage in different forms of liver disease. However, NK cells can limit liver fibrosis by killing hepatic stellate cell-derived myofibroblasts, which play a key role in this pathogenic process. Therefore, liver NK cells need to be tightly regulated in order to balance these beneficial and pathological effects.