Tumor Necrosis Factor Alpha-induced Protein 8 Research Articles

TNFAIP8 overexpression aggravates retinal pathophysiological features of diabetic retinopathy

Our previous research shown that tumor necrosis factor-alpha-induced protein 8 (TNFAIP8) is elevated in the plasma extracellular vesicles and vitreous humor in diabetic retinopathy (DR). TNFAIP8 also significantly increases the viability of human retinal microvascular endothelial cells (HRMECs) and promotes cell migration and tube formation in vitro. To comprehensively explore its role in DR, we investigated the effect of TNFAIP8 on DR development using an animal model in this study. A TNFAIP8-overexpressing adeno-associated virus (AAV) vector and streptozotocin-induced mouse model was used. The AAV-TNFAIP8 vector was injected into the mice intravitreally, and the effect was evaluated. The evaluation included analysis of retinal structure and function using electroretinography, optical coherence tomography, and histological assessment. The influence of TNFAIP8 on the avascular area, retinal leukostasis, and the expression levels of inflammatory factors was also determined. TNFAIP8 significantly decreased a/b-wave amplitude and retinal thickness in diabetic mice. Histological assessment showed that TNFAIP8 aggravated pathological abnormalities with distorted organization of the retina. TNFAIP8 also significantly increased the avascular area, leukostasis, and the expression of inflammatory factors, such as TNFα, IL1β, ICAM1, and GFAP, in the retina. The results of this study support the role of TNFAIP8 in DR pathogenesis. A mechanistic understanding of TNFAIP8 may offer novel therapeutic strategies.

Exploring Connections between Oral Microbiota, Short-Chain Fatty Acids, and Specific Cancer Types: A Study of Oral Cancer, Head and Neck Cancer, Pancreatic Cancer, and Gastric Cancer.

The association between oral microbiota and cancer development has been a topic of intense research in recent years, with compelling evidence suggesting that the oral microbiome may play a significant role in cancer initiation and progression. However, the causal connections between the two remain a subject of debate, and the underlying mechanisms are not fully understood. In this case-control study, we aimed to identify common oral microbiota associated with several cancer types and investigate the potential mechanisms that may trigger immune responses and initiate cancer upon cytokine secretion. Saliva and blood samples were collected from 309 adult cancer patients and 745 healthy controls to analyze the oral microbiome and the mechanisms involved in cancer initiation. Machine learning techniques revealed that six bacterial genera were associated with cancer. The abundance of Leuconostoc, Streptococcus, Abiotrophia, and Prevotella was reduced in the cancer group, while abundance of Haemophilus and Neisseria enhanced. G protein-coupled receptor kinase, H+-transporting ATPase, and futalosine hydrolase were found significantly enriched in the cancer group. Total short-chain fatty acid (SCFAs) concentrations and free fatty acid receptor 2 (FFAR2) expression levels were greater in the control group when compared with the cancer group, while serum tumor necrosis factor alpha induced protein 8 (TNFAIP8), interleukin-6 (IL6), and signal transducer and activator of transcription 3 (STAT3) levels were higher in the cancer group when compared with the control group. These results suggested that the alterations in the composition of oral microbiota can contribute to a reduction in SCFAs and FFAR2 expression that may initiate an inflammatory response through the upregulation of TNFAIP8 and the IL-6/STAT3 pathway, which could ultimately increase the risk of cancer onset.

CircPIM3 regulates taxol resistance in non-small cell lung cancer via miR-338-3p/TNFAIP8 axis.

Numerous work has revealed the involvement of circular RNA (circRNA) in regulating chemotherapy resistance. Here, we investigate circPIM3 role in taxol (Tax) resistance in non-small cell lung cancer (NSCLC). CircPIM3, microRNA (miR)-338-3p and tumor necrosis factor-alpha-induced protein-8 (TNFAIP8) expression were detected via quantitative real-time PCR, western blot or immunohistochemistry assay. Tax resistance was evaluated using cell counting kit-8, cell proliferation was measured by colony formation assay, cell cycle and apoptosis were examined via flow cytometry. The interplay between miR-338-3p and circPIM3 or TNFAIP8 was confirmed by dual-luciferase reporter assay. Finally, the effect of circPIM3 on Tax resistance in NSCLC in vivo was investigated by xenograft models. CircPIM3 and TNFAIP8 were upregulated in Tax-resistant NSCLC tissue and cell samples. Reducing circPIM3 expression inhibited Tax resistance, proliferation and induced cycle arrest and apoptosis in Tax-resistant NSCLC cells. Mechanically, circPIM3 absence led to downregulation of TNFAIP8 via absorbing miR-338-3p. Additionally, circPIM3 depletion increased Tax sensitivity of NSCLC in vivo. Silencing of circPIM3 suppressed Tax resistance in Tax-resistant NSCLC cells through regulation of the miR-338-3p/TNFAIP8 axis.

A “light” touch on PI3K to interrogate cancer drug resistance

In this issue of Cell Chemical Biology, Ueda etal. (2022) developed PPAP2 as an improved optogenetic tool to photo-induce PI3K signaling hyperactivation in cancer cells. They demonstrated that enhanced translation of tumor necrosis factor alpha-induced protein 8 (TNFAIP8) might explain PI3K hyperactivation-associated resistance toward DNA damaging anti-cancer alkylating agents.

Mechanistic insights into cancer drug resistance through optogenetic PI3K signaling hyperactivation

Hyperactivation of phosphatidylinositol 3-kinase (PI3K) signaling is a prominent feature in cancer cells. However, the mechanism underlying malignant behaviors in the state remains unknown. Here, we describe a mechanism of cancer drug resistance through the protein synthesis pathway, downstream of PI3K signaling. An optogenetic tool (named PPAP2) controlling PI3K signaling was developed. Melanoma cells stably expressing PPAP2 (A375-PPAP2) acquired resistance to a cancer drug in the hyperactivation state. Proteome analyses revealed that expression of the antiapoptotic factor tumor necrosis factor alpha-induced protein 8 (TNFAIP8) was upregulated. TNFAIP8 upregulation was mediated by protein translation from preexisting mRNA. These results suggest that cancer cells escape death via upregulation of TNFAIP8 expression from preexisting mRNA even though alkylating cancer drugs damage DNA.

CircHUWE1 Exerts an Oncogenic Role in Inducing DDP-Resistant NSCLC Progression Depending on the Regulation of miR-34a-5p/TNFAIP8.

Background Circular RNAs (circRNAs) are reported as competing endogenous RNAs (ceRNAs) and play key roles in non-small-cell lung cancer (NSCLC) progression. Thus, this study was aimed at clarifying underlying molecular mechanisms of circHUWE1 in NSCLC. Methods The quantitative real-time polymerase chain reaction (RT-qPCR) and western blot analyses were used for examining circHUWE1, microRNA-34a-5p (miR-34a-5p), and tumor necrosis factor alpha-induced protein 8 (TNFAIP8). IC50 of cisplatin (DDP) in A549/DDP and H1299/DDP cells and cell viability were analyzed by the Cell Counting Kit 8 (CCK-8) assay. Colony forming assay was performed to assess colony forming ability. Cell apoptosis and cell cycle distribution were determined by flow cytometry. Migrated and invaded cell numbers were examined by transwell assay. The association among circHUWE1, miR-34a-5p, and TNFAIP8 was analyzed by dual-luciferase reporter and RNA immunoprecipitation assays. A xenograft experiment was applied to clarify the functional role of circHUWE1 in vivo. Results circHUWE1 was upregulated in NSCLC tissues and cells, especially in DDP-resistant groups. circHUWE1 downregulation inhibited DDP resistance, proliferation, migration, and invasion while it induced apoptosis and cell cycle arrest of DDP-resistant NSCLC cells, which was overturned by silencing of miR-34a-5p. TNFAIP8 was a functional gene of miR-34a-5p, and the suppressive effects of miR-34a-5p overexpression on DDP-resistant NSCLC progression were dependent on the suppression of TNFAIP8. circHUWE1 inhibition also delayed tumor growth of DDP-resistant NSCLC cells. Conclusion circHUWE1 functioned as a promoter in DDP-resistant NSCLC by interaction with miR-34a-5p-TNFAIP8 networks, providing novel insight into DDP-resistant NSCLC diagnosis and treatment.

RETRACTED: TNFAIP8 Promotes Cisplatin Chemoresistance in Triple-Negative Breast Cancer by Repressing p53-Mediated miR-205-5p Expression

Tumor necrosis factor alpha-induced protein 8 (TNFAIP8) is implicated in the tumor progression and prognosis of triple-negative breast cancer (TNBC), but the detailed regulatory mechanism of TNFAIP8 in cisplatin tolerance in TNBC has not yet been investigated. TNFAIP8 was evidently upregulated in TNBC tumor tissues and cell lines. Knocking down TNFAIP8 led to impaired proliferation and elevated apoptosis of TNBC cells upon cisplatin (DDP) treatment. Mechanistic studies revealed that TNFAIP8 repressed the expression of p53 and p53-promoted microRNA (miR)-205-5p; moreover, miR-205-5p targeted multiple genes required for the cell cycle and repressed Akt phosphorylation, which thus inhibited the proliferation of TNBC cells. In addition, silencing of TNFAIP8 led to the upregulation of miR-205-5p and the restraint of the TRAF2-NF-κB pathway, which thus enhanced the suppressive effects of DDP on tumor growth in nude mice. This study revealed that TNFAIP8 was essential in the DDP tolerance formation of TNBC cells by reducing p53-promoted miR-205-5p expression. Thus, targeting TNFAIP8 might become a promising strategy to suppress TNBC progression.

Possible biomarkers for predicting lymph node metastasis of esophageal squamous cell carcinoma: a review.

Esophageal cancer is the eighth most common form of cancer worldwide, and esophageal squamous cell carcinoma (ESCC) is a major type of esophageal cancer that arises from epithelial cells of the esophagus. Local lymph node metastasis (LNM) is a typical sign of failure for ESCC clinical treatments, and a link has been established between LNM and the aberrant expression of specific biomarkers. In this review, we summarize what is known about nine factors significantly associated with LNM in ESCC patients: phosphatase and tensin homolog (PTEN), mucin 1, vascular endothelial growth factor-C, tumor necrosis factor alpha-induced protein 8 (TNFAIP8), Raf-1 kinase inhibitory protein, stathmin (STMN1), metastasis-associated protein 1, caveolin-1, and interferon-induced transmembrane protein 3. The function of these nine proteins involves four major mechanisms: tumor cell proliferation, tumor cell migration and invasion, epithelium–mesenchymal transition, and chemosensitivity. The roles of PTEN, STMN1, and TNFAIP8 involve at least two of these mechanisms, and we suggest that they are possible biomarkers for predicting LNM in ESCC. However, further retrospective research into PTEN, STMN1, and TNFAIP8 is needed to test their possibilities as indicators.

TNFAIP8 overexpression: a potential predictor of lymphatic metastatic recurrence in pN0 esophageal squamous cell carcinoma after Ivor Lewis esophagectomy.

Esophageal squamous cell carcinoma (ESCC) has a poor prognosis due to high lymphatic metastatic recurrence rates after Ivor Lewis esophagectomy. We sought to investigate the correlation between tumor necrosis factor alpha-induced protein 8 (TNFAIP8) expression and postoperative lymphatic recurrence in patients with pN0 ESCC. One hundred twenty-two patients with pN0 ESCC undergoing Ivor Lewis esophagectomy were enrolled in this study. TNFAIP8 overexpression was found in 73 (59.8%) tumor specimens. The 3-year lymphatic metastatic recurrence rate among TNFAIP8-overexpressing patients was significantly higher than in TNFAIP8-negative patients (p = 0.003). Multivariate Cox regression identified TNFAIP8 overexpression as an independent risk factor for lymphatic recurrence (p = 0.048). TNFAIP8 messenger RNA (mRNA) levels were significantly higher in patients with lymphatic recurrence than in patients without tumor recurrence (p = 0.019). Stable silencing of TNFAIP8 expression in ESCC-derived cells (Eca109) reduced proliferation, motility, and invasion and induced apoptosis. In addition, transient silencing of TNFAIP8 expression decreased cell motility and invasion and increased apoptosis in a second ESCC-derived cell line (KYSE150). Taken together, these findings suggest that TNFAIP8 overexpression is a potential biomarker to identify pN0 ESCC patients at higher risk of lymphatic recurrence who may benefit from adjuvant therapy.

The pro-apoptotic effects of TIPE2 on AA rat fibroblast-like synoviocytes via regulation of the DR5-caspase-NF-κB pathway in vitro.

TIPE2, also known as TNFAIP8L2, a member of the tumor necrosis factor-alpha-induced protein-8 (TNFAIP8) family, is known as an inhibitor in inflammation and cancer, and its overexpression induces cell death. We examined the role of TIPE2 with respect to adjuvant arthritis (AA)-associated pathogenesis by analyzing the TIPE2 regulation of death receptor (DR5)-mediated apoptosis in vitro. The results showed that TIPE2 was detected in normal fibroblast-like synoviocytes (FLSs), but scarcely observed in AA-FLSs. Therefore, recombinant MIGR1/TIPE2+/+ and control MIGR1 lentivirus vectors were transfected to AA-FLSs, which were denoted as TIPE2+/+-FLSs and MIGR1-FLSs, respectively. Our results showed that TIPE2+/+-FLSs were highly susceptible to ZF1-mediated apoptosis, and ZF1 was our own purification of an anti-DR5 single chain variable fragment antibody. Under the presence of TIPE2, the expression of DR5 was significantly increased compared with that of the MIGR1-FLS group. In contrast, the level of phosphorylated nuclear factor-kappa B (pNF-κB) was lower in the TIPE2+/+-FLS group treated with ZF1, whereas the activity of caspase was higher. Moreover, the rate of apoptosis in the TIPE2+/+-FLS group, which was pretreated with caspase inhibitor Z-VAD-FMK, was significantly decreased. In contrast, the apoptosis occurrence in the MIGR1-FLS group increased significantly with the pretreatment of the NF-κB inhibitor Bay. These results indicated that TIPE2 increased the apoptosis of AA-FLSs by enhancing DR5 expression levels, thereby promoting the activation of caspase and inhibiting the activation of NF-κB in AA-FLSs. TIPE2 might potentially act as a therapeutic target for rheumatoid arthritis.

P53 regulates expression of the early response gene tumor necrosis factor-α-induced protein 8 in macrophage (IRM6P.660)

Abstract The cell response to pathogens involves complex signaling cascades that affect expression of thousands of genes. Characterization of the regulation and function of genes involved in the stress response is critical since failure of this response can foster the development of chronic disorders such as autoimmune diseases and cancer. A growing body of evidence shows a role for the transcription factor p53 in the immune response. To better characterize the role of p53 in the innate immune response, we performed a microarray in primary human macrophages and identified the gene Tumor Necrosis Factor-Alpha Induced Protein-8 (TNFAIP8) as novel p53 target. ChIP-seq analysis shows strong binding of p53 to an intragenic region within TNFAIP8, which contains a functional p53 response element as confirmed with reporter assays. This region is an enhancer, since ChIP assays show enhancer-like histone modifications and 3C assays indicate chromatin looping with the promoter region. Very little is known about TNFAIP8 function; however, Tnfaip8 was previously reported to confer resistance to Staphylococcus aureus, suggesting a role in host defense. Studies are currently underway to characterize expression regulation and functions of TNFAIP8 in macrophages in response to TLR ligands. These results provide a better understanding of the role of p53 in the innate immune response and the regulation and function of the understudied TNFAIP8 gene.

Abstract 3836: TNFAIP8 protein expression in normal, inflammatory and neoplastic pancreatic tissues: Correlation with endocrine phenotype and advanced stage in ductal adenocarcinomas

Abstract Background: Tumor necrosis factor alpha induced protein 8 (TNFAIP8) is a transcription factor NF-kB inducible antiapoptotic and oncogenic molecule. This gene was initially discovered by comparison of expression profiles of primary and metastatic head and neck squamous cell carcinoma (hence earlier referred to as SCC-S2). Positive correlation between TNFAIP8 expression and cancer progression/poor prognosis has been suggested in a few human solid cancers including pancreatic and esophageal primaries. We were the first to publish the adverse prognostic implication of TNFAIP8 expression in prostatic adenocarcinomas. In this study, we evaluated the significance of this protein in normal, inflamed and neoplastic pancreatic tissues. Design: A total of 184 formalin-fixed, paraffin-embedded pancreatic tissues were analyzed; 151 samples in tissue microarray format [79 primary ductal carcinomas (PDC), 5 ductal adenocarcinomas from distant metastatic sites not matched to primary tumors (MDAC), 9 islet cell tumors (ICT) (one carcinoma), 2 chronic pancreatitis (CP), 29 normal adjacent to cancer, 8 normal adjacent to inflammation, and 19 normal pancreatic tissues] and 19 primary tumor resections [19 primary ductal adenocarcinomas (PDAC), 14 of these with normal tissue adjacent to the cancer]. All samples were immunostained by a manual method using a custom made anti-TNFAIP8 antibody as described earlier (Zhang et al., Int J Cancer, 133: 31-42, 2013). The staining pattern was semiquantitatively assessed based on staining intensity and distribution and the results were correlated with clinicopathologic variables. Results: Immunoreactivity for TNFAIP8 was predominantly cytoplasmic. TNFAIP8 protein overexpression was noted in 44/184 (24%) samples and correlated with tumor type [9/98 (9%) PDC/PDAC 2/5 (40%) unmatched distant MDAC, 5/9 (56%) (ICT) (1/1 carcinoma), 1/2 (50%) (CP), 15/43 (35%) normal adjacent to cancer, 5/8 (63%) normal adjacent to inflammation, and 7/19 (37%) normal pancreatic tissues, p<0.0001], with advanced tumor stage within PDC/PDAC [0/24 (0%) Stage I vs 3/44 (7%) Stage II vs 6/23 (26%) Stage III vs 0/7 (0%) Stage IV, p=0.010], and overall with gender [34/107 (32%) male vs 10/77 (13%) female, p=0.003]. Islets were present in 63 cases, all (100%) showing TNFAIP8 protein overexpression. Conclusion: TNFAIP8 immunohistochemical expression correlates with endocrine phenotype and portends poor prognosis in pancreatic ductal carcinomas. This protein may represent both a novel pathway in endocrine differentiation and a therapeutic target in the management of aggressive PDC, warranting further study. Citation Format: Jeffrey S. Ross, Bhaskar VS Kallakury, Hwa Jeong Lee, David M. Jones, Sanaz Ainechi, Gregory M. Sheehan, Christine E. Sheehan, Usha N. Kasid. TNFAIP8 protein expression in normal, inflammatory and neoplastic pancreatic tissues: Correlation with endocrine phenotype and advanced stage in ductal adenocarcinomas. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3836. doi:10.1158/1538-7445.AM2014-3836

Abstract 4724: Adverse prognostic significance of TNFAIP8 protein expression in non small cell lung cancer

Abstract Background: Tumor necrosis factor alpha induced protein 8 (TNFAIP8) is a transcription factor NF-kB inducible antiapoptotic and oncogenic molecule. Positive correlation between TNFAIP8 expression and cancer progression/poor prognosis has been described in a few human solid cancers including pancreatic and esophageal primaries. We were the first to publish the correlation of TNFAIP8 expression with high tumor grade and its independent predictor status for disease recurrence in prostatic adenocarcinomas. In this study, we evaluated the significance of this protein in non small cell lung cancer (NSCLC). Design: A total of 144 formalin-fixed, paraffin-embedded NSCLCs were analyzed (122 primary tumor resections and 22 tissue microarray samples); including 47 squamous cell carcinomas (SCC), 59 adenocarcinomas (AC), and 38 bronchioloalveolar carcinomas (BAC), were immunostained by a manual method using a custom made anti-TNFAIP8 antibody as described earlier (Zhang et al., Int J Cancer,133: 31-42, 2013). The staining pattern was semiquantitatively assessed based on staining intensity and distribution and the results were correlated with morphologic and prognostic variables. Results: Immunoreactivity for TNFAIP8 was predominantly cytoplasmic. TNFAIP8 protein overexpression was noted in 84/144 (58%) tumors and correlated with tumor type [45/59 (76)% AC vs 29/47 (62%) SCC vs 10/38 (26%) BAC, p<0.0001], overall with advanced tumor stage [24/31 (77%) advanced vs 60/113 (53%) early, p=0.015] and lymph node positive status [31/41 (76%) LN+ vs 53/103 (52%) LN-, p=0.008]. Within the AC subgroup, there was a trend toward correlation with advanced tumor stage [13/14 (93%) advanced vs 32/45 (71%) early, p=0.095] and lymph node positive status [18/20 (90%) LN+ vs 27/39 (69%) LN-, p=0.076]. On multivariate analysis, LN+ status independently predicted shortened survival. Conclusion: TNFAIP8 immunohistochemical expression portends poor prognosis in NSCLC and may constitute a novel therapeutic target in the management of aggressive NSCLC, warranting further study. Citation Format: Bhaskar VS Kallakury, Usha N. Kasid, Olga Voronel, Christopher B. Sheehan, Christine E. Sheehan, Jeffrey S. Ross. Adverse prognostic significance of TNFAIP8 protein expression in non small cell lung cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4724. doi:10.1158/1538-7445.AM2014-4724

Correlation of TNFAIP8 overexpression with the proliferation, metastasis, and disease-free survival in endometrial cancer

Tumor necrosis factor alpha-induced protein 8 (TNFAIP8) is an apoptosis regulator proven to have an important function in the proliferation, invasion, metastasis, and progression of malignancies. In this study, we investigated the clinical role of TNFAIP8 overexpression in endometrial cancer (EC) and determined the relationship of TNFAIP8 with the proliferative antigen Ki-67 and metastasis-related gene matrix metallopeptidase 9 (MMP9) in 225 tumor specimens by immunohistochemistry and western blot, in order to elucidate more information on the role of TNFAIP8 protein with regard to the pathogenesis of EC. An association was observed between TNFAIP8 overexpression and clinicopathologic factors, such as advanced International Federation of Gynecology and Obstetrics stage (P<0.001), higher histologic grade (P=0.017), deep myometrial invasion (P=0.030), lymphovascular space invasion (P=0.011), lymph node metastasis (P<0.001), and recurrence. Furthermore, TNFAIP8 overexpression was strongly correlated with MMP9 and Ki-67 expression in the progression of ECs. Patients with high expression of TNFAIP8 (P<0.001 for both) and Ki-67 (P=0.007 and P=0.008) had poor overall survival and disease-free survival (DFS) rates. MMP9 overexpression did not affect survival outcomes (P>0.05). Multivariate Cox regression analysis revealed that TNFAIP8 (P=0.029) and lymph node metastasis (P=0.022) were independent factors of DFS in patients with EC. These findings suggested that TNFAIP8 may be used as a prognostic marker for the recurrence of EC, and its promotion of the proliferation and metastasis in EC may be due to its mediation of Ki-67 and MMP9.

Variance of TNFAIP8 expression between tumor tissues and tumor-infiltrating CD4+ and CD8+ T cells in non-small cell lung cancer

Tumor necrosis factor alpha-induced protein 8 (TNFAIP8) has been recently documented in various malignancies, but its role in non-small cell lung cancer (NSCLC) remains uncertain. In the current study, we investigated the level of TNFAIP8 in NSCLC tissues, adjacent noncancerous lung tissues, healthy lung tissues, CD4+ T cells, and CD8+ T cells by real-time reverse transcription PCR (RT-PCR) and Western blot analysis. Results revealed that the mRNA level of TNFAIP8 was significantly increased in cancer tissue than in healthy lung tissue from donors (p < 0.001). Interestingly, adjacent noncancerous lung tissues also showed higher mRNA level of TNFAIP8 than healthy lung tissue from donors (p < 0.01). Similarly, protein level of TNFAIP8 was elevated in NSCLC tissues and adjacent noncancerous lung tissues. We further analyzed TNFAIP8 expression in CD4+ T cells and CD8+ T cells. Data demonstrated that both mRNA level and protein level were significantly decreased in tumor-infiltrating CD4+ and CD8+ T cells than in peripheral CD4+ and CD8+ T cells. Moreover, patients with advanced stages presented lower protein expression of TNFAIP8 in tumor-infiltrating CD8+ T cells than patients with primary stages (p < 0.05). These results provide evidence that TNFAIP8 plays critical roles in NSCLC and may be used as a therapeutic target for the disease.

TNFAIP8 Overexpression: Clinical Relevance to Esophageal Squamous Cell Carcinoma

Tumor necrosis factor alpha-induced protein 8 (TNFAIP8) is a suppressor of TNF-α mediated apoptosis, and its expression is induced by NF-κB activation. TNFAIP8 expression is significantly increased in various cancer cell lines. A correlation between TNFAIP8 overexpression, cancer progression, and poor prognosis has been described in many reports of human solid cancers. To clarify the functional and clinical significance of the cancer progression-related gene, TNFAIP8, in esophageal squamous cell carcinoma (ESCC), we used immunohistochemistry to demonstrate TNFAIP8 expression in ESCC. Next, TNFAIP8 expression was depleted by using siRNA to examine the function of TNFAIP8 in the proliferation and apoptosis induction of ESCC cell lines. We detected correlations between TNFAIP8 expression and TNM stage (P < 0.001), tumor depth (P = 0.002), lymph node metastasis (P = 0.013), distant metastasis (P = 0.001), lymphatic invasion (P < 0.001), and venous invasion (P < 0.001) among the clinicopathological characteristics of ESCC patients, and high TNFAIP8 expression was found in poor survival. TNFAIP8 depletion was significantly associated with apoptosis induction after cisplatin administration and reduced proliferation. Our results suggest that TNFAIP8 might be an effective therapeutic target for ESCC in the future.

Characterization and transcriptional regulation analysis of the porcine TNFAIP8L2 gene

Tumor necrosis factor alpha-induced protein 8-like 2 (TNFAIP8L2) is a new member of the tumor necrosis factor-alpha-induced protein 8 (TNFAIP8) family that functions as an important factor in the maintenance of immune homeostasis. In this study, we cloned the cDNA sequences and analyzed the genomic structure of porcine TNFAIP8L2. RH mapping using the IMpRH panel showed that this gene was closely linked to microsatellite marker SW512 in pig chromosome 4. Subcellular localization analysis showed GFP-TNFAIP8L2 fusion protein distributed in nucleus as well as cytoplasm including mitochondria and endoplasmic reticulum. Real-time PCR analysis revealed that porcine TNFAIP8L2 was more highly expressed in spleen than other tissues. To understand its characterization of transcriptional regulation, we cloned approximately 2 kb of 5'-regulatory region upstream to the porcine TNFAIP8L2 translational start site and generated sequential deletion constructs evaluated in dual-luciferase reporter assay. The results demonstrated that its core promoter is 435 base pairs (bp) upstream to the transcription initiation site. Then, site-directed mutation experiment combined with electrophoretic mobility shift assay (EMSA) indicated that M-CAT binding factor (MCBF) and activator protein 1 (AP-1) were important transcription factors for porcine TNFAIP8L2. These findings provide an important basis for further understanding of porcine TNFAIP8L2 regulation and function in swine.

TIPE2, a Negative Regulator of Innate and Adaptive Immunity that Maintains Immune Homeostasis

Immune homeostasis is essential for the normal functioning of the immune system, and its breakdown leads to fatal inflammatory diseases. We report here the identification of a member of the tumor necrosis factor-alpha-induced protein-8 (TNFAIP8) family, designated TIPE2, that is required for maintaining immune homeostasis. TIPE2 is preferentially expressed in lymphoid tissues, and its deletion in mice leads to multiorgan inflammation, splenomegaly, and premature death. TIPE2-deficient animals are hypersensitive to septic shock, and TIPE2-deficient cells are hyper-responsive to Toll-like receptor (TLR) and T cell receptor (TCR) activation. Importantly, TIPE2 binds to caspase-8 and inhibits activating protein-1 and nuclear factor-kappaB activation while promoting Fas-induced apoptosis. Inhibiting caspase-8 significantly blocks the hyper-responsiveness of TIPE2-deficient cells. These results establish that TIPE2 is an essential negative regulator of TLR and TCR function, and its selective expression in the immune system prevents hyperresponsiveness and maintains immune homeostasis.