Inhibition of NLRP3 inflammasome activation by A20 through modulation of NEK7.

The NLRP3 inflammasome, a pivotal component of innate immunity, has been implicated in various inflammatory disorders. The ubiquitin-editing enzyme A20 is well known to regulate inflammation and maintain homeostasis. However, the precise molecular mechanisms by which A20 modulates the NLRP3 inflammasome remain poorly understood. Here, our study revealed that macrophages deficient in A20 exhibit increased protein abundance and elevated mRNA level of NIMA-related kinase 7 (NEK7). Importantly, A20 directly binds with NEK7, mediating its K48-linked ubiquitination, thereby targeting NEK7 for proteasomal degradation. Our results demonstrate that A20 enhances the ubiquitination of NEK7 at K189 and K293 ubiquitinated sites, with K189 playing a crucial role in the binding of NEK7 to A20, albeit not significantly influencing the interaction between NEK7 and NLRP3. Furthermore, A20 disrupts the association of NEK7 with the NLRP3 complex, potentially through the OTU domain and/or synergistic effect of ZnF4 and ZnF7 motifs. Significantly, NEK7 deletion markedly attenuates the activation of the NLRP3 inflammasome in A20-deficient conditions, both in vitro and in vivo. This study uncovers a mechanism by which A20 inhibits the NLRP3 inflammasome.

Nomogram for predicting pathologic complete response to neoadjuvant chemoradiotherapy in patients with esophageal squamous cell carcinoma.

PURPOSE: A pathologic complete response (pCR) to neoadjuvant chemoradiotherapy (nCRT) is seen in up to 40% of the patients with esophageal squamous cell carcinoma (ESCC). No nomogram has been constructed for the prediction of pCR for patients whose primary chemotherapy was a taxane-based regimen. The aim is to identify characteristics associated with a pCR through analyzing multiple pre- and post-nCRT variables and to develop a nomogram for the prediction of pCR for these patients by integrating clinicopathological characteristics and hematological biomarkers. MATERIALS AND METHODS: We analyzed 293 patients with ESCC who underwent nCRT followed by esophagectomy. Clinicopathological factors, hematological parameters before nCRT, and hematotoxicity during nCRT were collected. Univariate and multivariate logistic regression analyses were performed to identify predictive factors for pCR. A nomogram model was built and evaluated for both discrimination and calibration. RESULTS: After surgery, 37.88% of the study patients achieved pCR. Six variables were included in the nomogram: sex, cN stage, chemotherapy regimen, duration of nCRT, pre-nCRT neutrophil-to-lymphocyte ratio (NLR), and pre-nCRT platelet-to-lymphocyte ratio (PLR). The nomogram indicated good accuracy and consistency in predicting pCR, with a C-index of 0.743 (95% confidence interval: 0.686, 0.800) and a p value of 0.600 (>0.05) in the Hosmer-Lemeshow goodness-of-fit test. CONCLUSIONS: Female, earlier cN stage, duration of nCRT (< 62 days), chemotherapy regimen of taxane plus platinum, pre-nCRT NLR (≥2.199), and pre-nCRT PLR (≥99.302) were significantly associated with a higher pCR in ESCC patients whose primary chemotherapy was a taxane-based regimen for nCRT. A nomogram was developed and internally validated, showing good accuracy and consistency.

The recent progress of myeloid-derived suppressor cell and its targeted therapies in cancers.

Myeloid-derived suppressor cells (MDSCs) are an immature group of myeloid-derived cells generated from myeloid cell precursors in the bone marrow. MDSCs appear almost exclusively in pathological conditions, such as tumor progression and various inflammatory diseases. The leading function of MDSCs is their immunosuppressive ability, which plays a crucial role in tumor progression and metastasis through their immunosuppressive effects. Since MDSCs have specific molecular features, and only a tiny amount exists in physiological conditions, MDSC-targeted therapy has become a promising research direction for tumor treatment with minimal side effects. In this review, we briefly introduce the classification, generation and maturation process, and features of MDSCs, and detail their functions under various circumstances. The present review specifically demonstrates the environmental specificity of MDSCs, highlighting the differences between MDSCs from cancer and healthy individuals, as well as tumor-infiltrating MDSCs and circulating MDSCs. Then, we further describe recent advances in MDSC-targeted therapies. The existing and potential targeted drugs are divided into three categories, monoclonal antibodies, small-molecular inhibitors, and peptides. Their targeting mechanisms and characteristics have been summarized respectively. We believe that a comprehensive in-depth understanding of MDSC-targeted therapy could provide more possibilities for the treatment of cancer.

Extracellular matrix remodeling in the tumor immunity.

The extracellular matrix (ECM) is a significant constituent of tumors, fulfilling various essential functions such as providing mechanical support, influencing the microenvironment, and serving as a reservoir for signaling molecules. The abundance and degree of cross-linking of ECM components are critical determinants of tissue stiffness. In the process of tumorigenesis, the interaction between ECM and immune cells within the tumor microenvironment (TME) frequently leads to ECM stiffness, thereby disrupting normal mechanotransduction and promoting malignant progression. Therefore, acquiring a thorough comprehension of the dysregulation of ECM within the TME would significantly aid in the identification of potential therapeutic targets for cancer treatment. In this regard, we have compiled a comprehensive summary encompassing the following aspects: (1) the principal components of ECM and their roles in malignant conditions; (2) the intricate interaction between ECM and immune cells within the TME; and (3) the pivotal regulators governing the onco-immune response in ECM.

Crystalline silica induces macrophage necrosis and causes subsequent acute pulmonary neutrophilic inflammation.

Crystalline silica (CS), an airborne particulate, is a major global occupational health hazard. While it is known as an important pathogenic factor in many severe lung diseases, the underlying mechanisms of its toxicity are still unclear. In the present study, we found that intra-tracheal instillation of CS caused rapid emergence of necrotic alveolar macrophages. Cell necrosis was a consequence of the release of cathepsin B in CS-treated macrophages, which caused dysfunction of the mitochondrial membrane. Damage to mitochondria disrupted Na+/K+ ATPase activity in macrophages, leading to intracellular sodium overload and the subsequent cell necrosis. Further studies indicate that CS-induced macrophage necrosis and the subsequent release of mitochondrial DNA could trigger the recruitment of neutrophils in the lung, which was regulated by the TLR9 signaling pathway. In conclusion, our results suggest a novel mechanism whereby CS leads to rapid macrophage necrosis through cathepsin B release, following the leakage of mitochondrial DNA as a key event in the induction of pulmonary neutrophilic inflammation. This study has important implications for the early prevention and treatment of diseases induced by CS.

Targeting the MDSCs of Tumors In Situ With Inhibitors of the MAPK Signaling Pathway to Promote Tumor Regression.

Myeloid-derived suppressor cells (MDSCs) are one of the major components of the tumor microenvironment. Evidence has shown differences in the functions and fates of MDSCs in the tumor tissue and the periphery. However, the exact mechanism that regulates MDSC function has not been completely clarified. In this study, we performed RNA sequencing of MDSCs derived from the spleen and tumor. Based on the results of our RNA-seq analysis, mitogen-activated protein kinases (MAPK) were significantly increased in tumor polymorphonuclear MDSCs (PMN-MDSCs) and monocytic MDSCs (M-MDSCs). Subsequently, 3 major MAPK pathways, including extracellular signal-regulated protein kinases (ERK), p38 and c-Jun NH2-terminal kinases (JNK), were studied to analyze the role of MAPKs in MDSCs. The ERK 1/2 inhibitor SCH772984 and the JNK inhibitor SP600125 significantly increased the apoptosis of both PMN-MDSCs and M-MDSCs in vitro. In addition, SCH772984 exerted a strong effect on inhibiting tumor growth. The flow cytometry analysis showed significant increases in the ratio of M1:M2 tumor-associated macrophages, meanwhile the number of CD4+, CD8+, CD4+CD69+ and CD8+CD69+ lymphocytes were increased after SCH772984 treatment. Our findings established the effect of MAPKs on the tumor microenvironment via MDSCs and may facilitate the development of new antitumor strategies.

A20: a master regulator of arthritis.

A20, also known as TNF-α-induced protein 3 (TNFAIP3), is an anti-inflammatory protein that plays an important part in both immune responses and cell death. Impaired A20 function is associated with several human inflammatory and autoimmune diseases. Although the role of A20 in mediating inflammation has been frequently discussed, its intrinsic link to arthritis awaits further explanation. Here, we review new findings that further demonstrate the molecular mechanisms through which A20 regulates inflammatory arthritis, and we discuss the regulation of A20 by many factors. We conclude by reviewing the latest A20-associated mouse models that have been applied in related research because they reflect the characteristics of arthritis, the study of which will hopefully cast new light on anti-arthritis treatments.

Iron deficiency is a possible risk factor causing right heart failure in Tibetan children living in high altitude area.

The aim of the study is to discuss the risk factor of right heart failure (RHF) especially the association of iron deficiency with RHF in Tibetan children who live in high altitude area. In this retrospective study, we collected the data of Tibetan children from January 2011 to December 2018 in our hospital. The patients included in the study had the following data: age, gender, ferritin, echocardiography, hemoglobin, C-reaction protein, and altitude of residence. According to whether RHF was diagnosed, the patients were divided into RHF group and non-RHF group. Totally 133 patients were included with 59 in RHF group and 74 in non-RHF group. In single factor analysis, age (P = .008), altitude of residence (P < .001), ferritin (P < .001), and pulmonary arterial systolic pressure (P < .001) showed significant difference between the 2 groups. Binary logistic regression was performed to further identify the association of the clinical factors with RHF. Higher pulmonary arterial systolic pressure (odds ratio: 29.303, 95% confidence interval: 5.249-163.589, P < .001) and lower ferritin level (odds ratio: 5.849, 95% confidence interval: 1.585-21.593, P = .008) were independent risk factors associated with RHF. In receiver-operating characteristic curve, the optimal cutoff value of ferritin level was 14.6 µg/L with the sensitivity of 81.4% and specificity of 89.2%. As continuous variable, the correlation between ferritin and RHF was not certain (P = .281). Due to the possibility that iron deficiency be a risk factor of RHF in Tibetan children, prevention and treatment of iron deficiency might be a potential way in reducing the incidence of RHF in this high altitude area.

In situ antitumor vaccination: Targeting the tumor microenvironment.

Tumor microenvironment is known to play important roles in tumor progression. Many therapies, targeting the tumor microenvironment, are designed and applied in the clinic. One of these approaches is in situ antitumor therapy. This way, bacteria, antibodies, plasmid DNA, viruses, and cells are intratumorally delivered into the tumor site as "in-situ antitumor vaccine," which seeks to enhance immunogenicity and generate systemic T cell responses. In addition, this intratumoral therapy can alter the tumor microenvironment from immunosuppressive to immunostimulatory while limiting the risk of systemic exposure and associated toxicity. Contemporarily, promising preclinical results and some initial success in clinical trials have been obtained after intratumoral therapy.

Irradiated lactic acid-stimulated tumour cells promote the antitumour immunity as a therapeutic vaccine.

Low pH and lactate accumulation are characteristic features of the tumour microenvironment. With our study finding that high concentrations of lactic acid can inhibit tumour growth, it is conceivable that the administration of lactic acid could promote antitumour immunity in the context of a tumour vaccine. To test this concept, we studied the antitumour effect of irradiated tumour cells stimulated with lactic acid in mouse xenograft models to potentially improve whole-cell tumour vaccines. In this study, we found that the effects of lactic acid-stimulated tumour cells on dendritic cells (DCs) included enhancing phagocytic function and stimulating maturation and aggregation. Moreover, lactic acid could potentiate the immunogenicity of an irradiated whole-tumour cell vaccine and thus inhibit tumour growth. We further verified that the antitumour immune response was mediated by CD8+ T cells. In addition, interferon-γ-expressing CD4+ and CD8+ T cell numbers increased in the spleen and lymph nodes of mice immunized with the irradiated lactic acid-stimulated cells. Furthermore, changes in the tumour microenvironment were also observed in this study. Our findings may be helpful for developing a new strategy for cancer therapy.

Study of the association between five polymorphisms and risk of hepatocellular carcinoma: A meta-analysis.

BACKGROUND: Recently, several studies have investigated the association between polymorphisms in miR-146a rs2910164, miR-196a2 rs11614913, miR-499 rs3746444, miR-149 rs229283, miR-34b/c rs4938723, and hepatocellular carcinoma (HCC), which showed inconclusive results. METHODS: A publication search was performed in PubMed, ExcerptaMedica Database, Chinese Biomedical Literature Database, and Chinese National Knowledge Infrastructure to collect relevant medical data published through February 2016. The aim of this study was to ascertain the association between HCC and micro-RNAs. A total of 21 studies were included in our study, which showed that miR-146a rs2910164 polymorphism has a significant association with HCC in the allele, recessive, and homozygous models overall [allele model: odds ratio (OR) = 0.927, 95% confidence interval (CI): 0.869-0.988, p = 0.02; recessive model: OR = 0.893, 95% CI: 0.814-0.981, p = 0.018; homozygous model: OR = 0.853, 95% CI: 0.744-0.978, p = 0.023] and in Asian populations (allele model: OR = 0.921, 95% CI: 0.863-0.983, p = 0.014; recessive model: OR = 0.893, 95% CI: 0.814-0.981, p = 0.019; homozygous model: OR = 0.851, 95% CI: 0.741-0.977, p = 0.022). For miR-196a2 rs11614913, significant statistical heterogeneity overall and in Asian populations was identified in the comparison of the allele, recessive, homozygous, and heterozygous models (overall: allele model: OR = 0.889, 95% CI: 0.842-0.94, p < 0.001; recessive model: OR = 0.837, 95% CI: 0.723-0.970, p = 0.018; homozygous model: OR = 0.722, 95%CI: 0.575-0.906, p = 0.005; heterozygous model: OR = 0.532, 95% CI: 0.37-0.765, p = 0.001), and also has a decreased risk of HCC in Caucasians in all genetic models except for the heterozygous model (allele model: OR = 0.658, 95% CI: 0.49-0.885, p = 0.006; dominant model: OR = 0.641, 95% CI: 0.418-0.981, p = 0.041; recessive model: OR = 0.489, 95% CI: 0.278-0.862, p = 0.013; homozygous model: OR = 0.414, 95% CI: 0.222-0.772, p = 0.005). Only the recessive models produced a significant association between miR-499 rs3746444 polymorphism and HCC risk (recessive model: OR = 1.283, 95% CI: 1.008-1.632, p = 0.043). RESULTS: The analysis for miR-146a rs2910164 polymorphisms by racial decent found the same association between miR-146a rs2910164 polymorphism and susceptibility to HCC in Asians, but no significance risk association was observed in Caucasians. The meta-analysis results showed that miR-196a2 rs11614913 was associated with a decreased risk of HCC in Caucasians in all genetic models except for the heterozygous model. In the Asian population, miR-499 rs3746444 polymorphism was associated with a decreased risk of HCC in recessive models. This meta-analysis showed that no significant statistical heterogeneity was identified in miR-149 rs2292832 and miR-34b/c rs4938723. CONCLUSION: Our findings supported the proposition that the polymorphisms of miR-146a rs2910164, miR-196a2 rs11614913, and miR-196a2 rs11614913 may contribute to the susceptibility of HCC.

Inhibition of A20 expression in tumor microenvironment exerts anti-tumor effect through inducing myeloid-derived suppressor cells apoptosis.

Myeloid-derived suppressor cells (MDSCs) are known to play important roles in the development of immunosuppressive tumor microenvironment. A20 is a zinc-finger protein which could negatively regulate apoptosis in several cell types. However, the role of A20 in tumor microenvironment remains largely unknown. In this study, we found that A20 was over-expressed in MDSCs. The treatment of tumor-bearing mice with small interfering RNA targeting A20 (si-A20) inhibited the growth of tumors. The infiltration of MDSCs was dramatically reduced after si-A20 treatment, as compared to control groups, whereas the numbers of dendritic cells and macrophages were not affected. Also, injection of si-A20 improved T cell mediated tumor-specific immune response. Depletion of MDSCs with anti-Gr1 antibody showed similar antitumor effect and improved T cell response. TNF-α was highly expressed after si-A20 injection. Furthermore, si-A20 induced apoptosis of MDSCs in the presence of TNF-α both in vivo and in vitro. Cleaved Caspase-3 and Caspase-8 were elevated with the activation of JNK pathway after the induction of MDSC apoptosis by si-A20. Thus, our findings suggested that knockdown of A20 in tumor site inhibited tumor growth at least through inducing the apoptosis of MDSCs. A20 might be a potential target in anticancer therapy.

[Infiltrated T Cells Induce the Accumulation of Myeloid-derived Suppressor Cells in Tumor Microenvironment].

OBJECTIVE: To determine the role of infiltrated T cells in the accumulation of myeloid-derived suppressor cells (MDSCs) in tumor microenvironment. METHODS: T-cell-deficient nude mice models were established using BALB/c mice. Growth of tumors was compared between those with and without adoptive transfer of T cells. Pathological changes of the tumors were examined with HE histological analysis. The levels of MDSCs were detected with flow cytometry (FACS). RESULTS: Tumor growth was promoted in T-cell-deficient nude mice, which was accompanied with lower levels of MDSCs compared with BALB/c mice (P < 0.05). T cell transfer increased the level of MDSCs significantly (P < 0.05). T cells depletion decreased the level of MDSCs (P < 0.05). CONCLUSION: Infiltrated T cells induce the accumulation of MDSCs in tumor microenvironment, and influence tumor growth.

Associations of single nucleotide polymorphisms in miR-146a, miR-196a, miR-149 and miR-499 with colorectal cancer susceptibility.

BACKGROUND: MicroRNAs (miRNAs) are an abundant class of endogenous small non-coding RNAs of 20-25 nucleotides in length that function as negative gene regulators. MiRNAs play roles in most biological processes, as well as diverse human diseases including cancer. Recently, many studies investigated the association between SNPs in miR-146a rs2910164, miR-196a2 rs11614913, miR-149 rs229283, miR-499 rs3746444 and colorectal cancer (CRC), which results have been inconclusive. METHODOLOGY/PRINCIPAL FINDINGS: PubMed, EMBASE, CNKI databases were searched with the last search updated on November 5, 2013. For miR-196a2 rs11614913, a significantly decreased risk of CRC development was observed under three genetic models (dominant model: OR = 0.848, 95%CI: 0.735-0.979, P = 0.025; recessive model: OR = 0.838, 95%CI: 0.721-0.974, P = 0.021; homozygous model: OR = 0.754, 95%CI: 0.627-0.907, P = 0.003). In the subgroup analyses, miR-196a2*T variant was associated with a significantly decreased susceptibility of CRC (allele model: OR = 0.839, 95%CI: 0.749-0.940, P = 0.000; dominant model: OR = 0.770, 95%CI: 0.653-0.980, P = 0.002; recessive model: OR = 0.802, 95%CI: 0.685-0.939, P = 0.006; homozygous model: OR = 0.695, 95%CI: 0.570-0.847, P = 0.000). As for miR-149 rs2292832, the two genetic models (recessive model: OR = 1.199, 95% CI 1.028-1.398, P = 0.021; heterozygous model: OR = 1.226, 95% CI 1.039-1.447, P = 0.013) demonstrated increased susceptibility to CRC. On subgroup analysis, significantly increased susceptibility of CRC was found in the genetic models (recessive model: OR = 1.180, 95% CI 1.008-1.382, P = 0.040; heterozygous model: OR = 1.202, 95% CI 1.013-1.425, P = 0.013) in the Asian group. CONCLUSIONS: These findings supported that the miR-196a2 rs11614913 and miR-149 rs2292832 polymorphisms may contribute to susceptibility to CRC.

Association between rs11614913 polymorphism in miR-196a2 and colorectal cancer risk: a meta-analysis.

BACKGROUND: MicroRNAs (miRNAs) are small non-coding RNAs of 20-22 nucleotides in length, which regulate the translation or degradation of human messenger RNA (mRNA). MiRNAs involve in the regulation of most biological processes, as well as human diverse diseases including cancer. Recently, many studies investigated the association between miR-196a2 rs11614913 polymorphism and colorectal cancer (CRC), which showed inconclusive results. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a meta-analysis of 6 studies that included 1800 cases and 2329 controls. There was a statistically decreased risk of CRC in dominant model, recessive model and homozygous model. In the Asian group, significantly decreased susceptibility of CRC was found in allele model, dominant model, recessive model and homozygous model. As for the Caucasian group, none of genetic models demonstrates significant association between miR-196a2 rs11614913 polymorphism and susceptibility of CRC. CONCLUSIONS: These findings supported that miR-196a2 rs11614913 polymorphism may contribute to the susceptibility of CRC.