TIPE2 inhibits TNF-α-induced hepatocellular carcinoma cell metastasis via Erk1/2 downregulation and NF-κB activation

TIPE2 gene transfer ameliorates aging-associated osteoarthritis in a progeria mouse model by reducing inflammation and cellular senescence

Osteoarthritis (OA) pain is often associated with the expression of tumor necrosis factor alpha (TNF-α), suggesting that TNF-α is one of the main contributing factors that cause inflammation, pain, and OA pathology. Thus, inhibition of TNF-α could potentially improve OA symptoms and slow disease progression. Anti-TNF-α treatments with antibodies, however, require multiple treatments and cannot entirely block TNF-α. TNF-α-induced protein 8-like 2 (TIPE2) was found to regulate the immune system's homeostasis and inflammation through different mechanisms from anti-TNF-α therapies. With a single treatment of adeno-associated virus (AAV)-TIPE2 gene delivery in the accelerated aging Zmpste24-/- (Z24-/-) mouse model, we found differences in Safranin O staining intensity within the articular cartilage (AC) region of the knee between TIPE2-treated mice and control mice. The glycosaminoglycan content (orange-red) was degraded in the Z24-/- cartilage while shown to be restored in the TIPE2-treated Z24-/- cartilage. We also observed that chondrocytes in Z24-/- mice exhibited a variety of senescent-associated phenotypes. Treatment with TIPE2 decreased TNF-α-positive cells, β-galactosidase (β-gal) activity, and p16 expression seen in Z24-/- mice. Our study demonstrated that AAV-TIPE2 gene delivery effectively blocked TNF-α-induced inflammation and senescence, resulting in the prevention or delay of knee OA in our accelerated aging Z24-/- mouse model.

Multifaceted role of NF-κB in hepatocellular carcinoma therapy: Molecular landscape, therapeutic compounds and nanomaterial approaches

The predominant kind of liver cancer is hepatocellular carcinoma (HCC) that its treatment have been troublesome difficulties for physicians due to aggressive behavior of tumor cells in proliferation and metastasis. Moreover, stemness of HCC cells can result in tumor recurrence and angiogenesis occurs. Another problem is development of resistance to chemotherapy and radiotherapy in HCC cells. Genomic mutations participate in malignant behavior of HCC and nuclear factor-kappaB (NF-κB) has been one of the oncogenic factors in different human cancers that after nuclear translocation, it binds to promoter of genes in regulating their expression. Overexpression of NF-κB has been well-documented in increasing proliferation and invasion of tumor cells and notably, when its expression enhances, it induces chemoresistance and radio-resistance. Highlighting function of NF-κB in HCC can shed some light on the pathways regulating progression of tumor cells. The first aspect is proliferation acceleration and apoptosis inhibition in HCC cells mediated by enhancement in expression level of NF-κB. Moreover, NF-κB is able to enhance invasion of HCC cells via upregulation of MMPs and EMT, and it triggers angiogenesis as another step for increasing spread of tumor cells in tissues and organs. When NF-κB expression enhances, it stimulates chemoresistance and radio-resistance in HCC cells and by increasing stemness and population of cancer-stem cells, it can provide the way for recurrence of tumor. Overexpression of NF-κB mediates therapy resistance in HCC cells and it can be regulated by non-coding RNAs in HCC. Moreover, inhibition of NF-κB by anti-cancer and epigenetic drugs suppresses HCC tumorigenesis. More importantly, nanoparticles are considered for suppressing NF-κB axis in cancer and their prospectives and results can also be utilized for treatment of HCC. Nanomaterials are promising factors in treatment of HCC and by delivery of genes and drugs, they suppress HCC progression. Furthermore, nanomaterials provide phototherapy in HCC ablation.

Tissue mechanics modulate PCNP expression in oral squamous cell carcinomas with different differentiation

Background

PEST-containing nuclear protein (PCNP), a novel zinc finger protein, participates in cell cycle regulation. Previous studies have confirmed that PCNP plays a role in mediating cellular development and invasion in a variety of cancer types. However, the relationship between PCNP expression and the occurrence and development of oral squamous cell carcinoma (OSCC) requires further exploration. In this study, we used biological atomic force microscopy to examine the histomorphological and mechanical properties of OSCC to explore the relationship between PCNP expression and differentiation of OSCC.

Methods

Seventy-seven OSCC samples with varying degrees of differentiation were selected for hematoxylin and eosin staining, immunohistochemistry, and cellular mechanical measurement. The expression of PCNP and the mechanical properties such as stiffness and roughness of the tissue interface in OSCC samples were investigated. The Kaplan-Meier survival curve was utilized to assess the relationship of PCNP expression with patient survival.

Results

The level of PCNP was significantly higher in well-differentiated OSCC than in moderately and poorly differentiated OSCC (P < 0.001). High expression of PCNP was specifically associated with higher tumor differentiation, lack of lymph node metastasis, and lower tumor node metastasis stage (all P < 0.05). Patients with high PCNP expression had a higher survival rate than those with low PCNP expression. The average variation of stiffness within a single tissue ranged from 347 kPa to 539 kPa. The mean surface roughness of highly, moderately, and poorly differentiated OSCC and paraneoplastic tissues were 795.53 ± 47.2 nm, 598.37 ± 45.76 nm, 410.16 ± 38.44 nm, and 1010.94 ± 119.07 nm, respectively. Pearson correlation coefficient demonstrated a positive correlation between PCNP expression and tissue stiffness of OSCC (R = 0.86, P < 0.001).

Conclusion

The expression of PCNP was positively correlated with patient survival, tumor differentiation, and mechanical properties of tissue interfaces. PCNP is a potential biomarker for the early diagnosis and staging of OSCC. Furthermore, determination of the mechanical properties of the tissue interface could provide further useful information required for the detection and differentiation of OSCC.

Tumor necrosis factor-α induced protein 8 (TNFAIP8/TIPE) family is differentially expressed in oral cancer and regulates tumorigenesis through Akt/mTOR/STAT3 signaling cascade

BACKGROUND

Highest incidence of oral cancer is reported in India with reduced survival rate in the advanced stages due to lack of effective biomarkers. Therefore, it is essential to develop novel biomarkers for the better management of this disease. In the current study, TNFAIP8/TIPE protein family comprising of four proteins is explored for its role in oral cancer.

METHODS

IHC analysis of oral cancer TMA and Western blot analysis of tobacco treated oral cancer cells were performed to determine the differential expression of TIPE proteins in oral cancer. Further, CRISPR/Cas9-mediated gene editing was done to generate TIPE proteins' knockouts and MTT, colony formation, wound healing, cell cycle and Western blot analysis were performed to determine the effect of gene knockouts on various cancer hallmarks and the associated molecular targets of TIPE proteins.

RESULTS AND DISCUSSION

IHC results revealed that expression of TIPE, TIPE2 and TIPE3 were upregulated and TIPE1 was downregulated in oral cancer tissues compared to normal tissues. Similar results were observed upon treating oral cancer cells with tobacco carcinogens. Furthermore, knockout of TIPE or TIPE2 or TIPE3 significantly reduced the survival, proliferation, colony formation and migration of oral cancer cells whereas knockout of TIPE1 had an opposite effect. Further, TIPE, TIPE2 and TIPE3 knockout-mediated inhibition of proliferation was associated with inhibition of cell cycle progression at S or G2/M phases, and downregulation of proteins involved in cancer progression. We found that TIPE, TIPE1 and TIPE2 proteins regulate oral cancer progression through modulation of Akt/mTOR signaling cascade, whereas TIPE3 acts through an Akt-independent mTOR/STAT3 pathway.

CONCLUSION

Collectively, the TIPE proteins were proved to play significant roles in the progression of oral cancer thus warranting research and clinic attention for their therapeutic and prognostic values and raising the importance of specific targeting of TIPE proteins in cancer treatment.

Tumor Necrosis Factor α-Induced Protein 8-Like 2 Alleviates Nonalcoholic Fatty Liver Disease Through Suppressing Transforming Growth Factor Beta-Activated Kinase 1 Activation

BACKGROUND AND AIMS

NAFLD prevalence has increased rapidly and become a major global health problem. Tumor necrosis factor α-induced protein 8-like 2 (TIPE2) plays a protective role in a cluster of liver diseases, such as autoimmune hepatitis, hepatitis B, and hepatocellular carcinoma. However, the function of TIPE2 in NAFLD remains unknown. Here, we investigated the role of TIPE2 in the development of NAFLD.

APPROACH AND RESULTS

Our study found that in vitro overexpression or knockout of TIPE2 significantly ameliorated or aggravated lipid accumulation and inflammation in hepatocytes exposed to metabolic stimulation, respectively. Consistently, in vivo hepatic steatosis, insulin resistance, inflammation, and fibrosis were alleviated in hepatic Tipe2-transgenic mice but exaggerated in hepatic Tipe2-knockout mice treated by metabolic challenges. RNA sequencing revealed that TIPE2 was significantly associated with the mitogen-activated protein kinase pathway. Mechanistic experiments demonstrated that TIPE2 bound with transforming growth factor beta-activated kinase 1 (TAK1), prevented tumor necrosis factor receptor-associated factor 6-mediated TAK1 ubiquitination and subsequently inhibited the TAK1 phosphorylation and activation of TAK1-c-Jun N-terminal kinase (JNK)/p38 signaling. Further investigation showed that blocking the activity of TAK1 reversed the worsening of hepatic metabolic disorders and inflammation in hepatic-specific Tipe2-knockout hepatocytes and mice treated with metabolic stimulation.

CONCLUSIONS

TIPE2 suppresses NAFLD advancement by blocking TAK1-JNK/p38 pathway and is a promising target molecule for NAFLD therapy.

TIPE2 Suppresses Malignancy of Pancreatic Cancer Through Inhibiting TGFβ1 Mediated Signaling Pathway

Pancreatic cancer is one of the major reasons of cancer-associated deaths due to poor diagnosis, high metastasis and drug resistance. Therefore, it is important to understand the cellular and molecular mechanisms of pancreatic cancer to identify new targets for the treatment. TIPE2 is an essential regulator of tumor apoptosis, inflammation and immune homeostasis. However, the role of TIPE2 is still not fully understood in pancreatic cancer. In this study, we found the expression of TIPE2 was decreased in pancreatic cancer tissues compare to paracancerous tissues, which was negatively correlated with tumor size in patients. Overexpression of TIPE2 significantly decreased cell proliferation, metastasis and increased apoptotic events in pancreatic cancer cell lines. Moreover, the results obtained from real time PCR and western blot revealed that TIPE2 was also involved in inhibiting MMPs and N-Cadherin expression while increasing Bax expression in pancreatic cancer cells. Similarly, TIPE2 could inhibit tumor growth in vivo, decrease the expression of Ki-67 and N-Cadherin, and increase the expression of Bax by IHC analysis in tumor tissues isolated from tumor-bearing mice. Mechanistic studies exhibited that TIPE2 might suppress pancreatic cancer development through inhibiting PI3K/AKT and Raf/MEK/ERK signaling pathways triggered by TGFβ1. Moreover, the tumor-infiltrating lymphocytes from tumor-bearing mice were analyzed by flow cytometry, and showed that TIPE2 could promote T cell activation to exert an anti-tumor effect possibly through activation of DCs in a TGFβ1 dependent manner. In general, we described the multiple regulatory mechanisms of TIPE2 in pancreatic tumorigenesis and tumor microenvironment, which suggested TIPE2 may act as a potential therapeutic target in pancreatic cancer.

TIPE2 inhibits the migration and invasion of endometrial cells by targeting β-catenin to reverse epithelial-mesenchymal transition

STUDY QUESTION

Do changes in tumor necrosis factor-α-induced protein 8 (TNFAIP8)-like 2 (TIPE2) levels in endometrium of patients with adenomyosis alter the proliferation, migration and invasion ability of endometrial cells?

SUMMARY ANSWER

TIPE2 expression levels were low in eutopic and ectopic endometrium of adenomyosis patients, and TIPE2 inhibited the migration and invasion of endometrial cells, mainly by targeting β-catenin, to reverse the epithelial-mesenchymal transition (EMT).

WHAT IS KNOWN ALREADY

Adenomyosis is a benign disease, but it has some pathophysiological characteristics similar to the malignant tumor. TIPE2 is a novel negative immune regulatory molecule, and it also participates in the development of malignant tumors.

STUDY DESIGN, SIZE, DURATION

Control endometrium (n = 48 women with non-endometrial diseases) and eutopic/ectopic endometrium from patients with adenomyosis (n = 50), human endometrial cancer cell lines, and primary endometrial cells from the eutopic endometrium of adenomyosis patients were used in the study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The expression level of TIPE2 mRNA and protein in the eutopic/ectopic endometrial tissues of adenomyosis patients and control endometrium was determined by quantitative RT-PCR (qRT-PCR), western blot and immunohistochemistry. The effects of TIPE2 overexpression and knockdown on the proliferation, migration and invasion of endometrial cell lines and primary adenomyotic endometrial cells were determined using a cell counting kit-8, 5-ethynyl-2'-deoxyuridine assay, colony-forming assay, transwell migration assay and matrigel invasion assay. The expression of EMT-related markers and signal molecules was detected by western blot. The interaction between TIPE2 and β-catenin was detected by co-immunoprecipitation and laser confocal microscopy.

MAIN RESULTS AND THE ROLE OF CHANCE

The mRNA and protein expression levels of TIPE2 in the eutopic and ectopic endometrial tissues of adenomyosis patients were significantly downregulated compared with the control endometrium (P ˂ 0.01). TIPE2 could bind to β-catenin and inhibit the nuclear translocation of β-catenin, downregulate the expression of stromal cell markers, upregulate the expression of glandular epithelial cell markers, decrease the occurrence of epithelial-mesenchymal transition (EMT) and suppress the migration and invasion of endometrial cells (P ˂ 0.01).

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

In this study, the experiments were performed only in eutopic and ectopic endometrial tissues, endometrial cancer cell lines and primary adenomyotic endometrial cells. A mouse model of adenomyosis will be constructed to detect the effects of TIPE2 in vivo.

WIDER IMPLICATIONS OF THE FINDINGS

These results suggest that TIPE2 is involved in the development of adenomyosis, which provides a potential new diagnostic and therapeutic strategy for the treatment of adenomyosis.

STUDY FUNDINGS/COMPETING INTEREST(S)

This present study was supported by grants from the National Natural Science Foundation of China (81471437, 81771554), Natural Science Foundation of Shandong (ZR2018MH013), Science and technology development plan provided by Health and Family Planning Committee in Shandong (2014-25). The authors declare that they have no conflicts of interest.

Harnessing Tumor Necrosis Factor Alpha to Achieve Effective Cancer Immunotherapy

Tumor necrosis factor alpha (TNFα) is a pleiotropic cytokine known to have contradictory roles in oncoimmunology. Indeed, TNFα has a central role in the onset of the immune response, inducing both activation and the effector function of macrophages, dendritic cells, natural killer (NK) cells, and B and T lymphocytes. Within the tumor microenvironment, however, TNFα is one of the main mediators of cancer-related inflammation. It is involved in the recruitment and differentiation of immune suppressor cells, leading to evasion of tumor immune surveillance. These characteristics turn TNFα into an attractive target to overcome therapy resistance and tackle cancer. This review focuses on the diverse molecular mechanisms that place TNFα as a source of resistance to immunotherapy such as monoclonal antibodies against cancer cells or immune checkpoints and adoptive cell therapy. We also expose the benefits of TNFα blocking strategies in combination with immunotherapy to improve the antitumor effect and prevent or treat adverse immune-related effects.

Expression of TIPE family members in human colorectal cancer

The tumor necrosis factor α-induced protein 8 (TNFAIP8)-like (TIPE) protein family comprises four members, namely TNFAIP8, TIPE1, TIPE2 and TIPE3, which are involved in multiple processes in cancer. The current study aimed to investigate the expression patterns and potential clinical roles of the TIPE family members in human colorectal cancer (CRC). Paired tumor and adjacent tissue samples were collected from 49 patients with CRC, and the relative mRNA expression levels of the TIPE family members in these samples were evaluated by using reverse transcription-quantitative PCR, and the protein levels in five randomly selected pairs of tumor and adjacent tissue samples were detected by western blot analysis. The mRNA expression levels of the TIPE family members were significantly downregulated in CRC tumor tissues compared with those in the adjacent tissues; however, within each sample, TNFAIP8 and TIPE3 protein levels were only partially consistent with their mRNA levels. In addition, the mRNA expression levels between each pair of TIPE family members exhibited a positive linear relationship, and TIPE2 mRNA levels exhibited strong linear associations with those of TNFAIP8 and TIPE1. TNFAIP8 mRNA expression levels in tumor tissues were significantly associated with the tumor differentiation grade, and TIPE2 mRNA expression levels in tumor tissues were significantly associated with sex. TIPE1 and TIPE3 mRNA expression levels in tumor tissues exhibited no associations with patient clinicopathological characteristics. In addition, the mRNA expression patterns of the TIPE family members were analyzed using data from The Cancer Genome Atlas data set, and the results also demonstrated that TNFAIP8, TIPE2 and TIPE3 mRNA levels were downregulated in patients with colon adenocarcinoma compared with those in normal controls. These results provided evidence that the four members of the TIPE family may affect each other to mediate the carcinogenesis of CRC, and that TIPE2 may serve an important role in CRC.

Regulatory Roles of Tumor Necrosis Factor-α-Induced Protein 8 Like-Protein 2 in Inflammation, Immunity and Cancers: A Review

Tumor necrosis factor-alpha (TNF-α)-induced protein 8 (TNFAIP8/TIPE) family, including TNFAIP8 (TIPE), TNFAIP8 like-protein 1 (TNFAIP8L1/TIPE1), TNFAIP8 like-protein 2 (TNFAIP8L2/TIPE2), and TNFAIP8 like-protein 3 (TNFAIP8L3/TIPE3), plays a vital role in regulating inflammatory responses, immune homeostasis, and cancer development. Over the last decade, studies have shown that TIPE2 protein is differentially expressed in diverse cells and tissues. The dysregulation of TIPE2 protein can lead to dysregulation of inflammatory responses and immune homeostasis, and change the basic characteristics of cancers. In consideration of the immeasurable values of TIPE2 in diagnosis, treatment, and prognosis of various human diseases, this review will focus on the expression pattern, structure, and regulatory roles of TIPE2 in inflammation, immunity, and cancers.

The enigmatic role of TIPE2 in asthma

Unlike other members of the tumor necrosis factor (TNF)-α-induced protein 8 (TNFAIP8/TIPE) family that play a carcinogenic role and regulate apoptosis, TNFAIP8-like 2 (TIPE2) can not only maintain immune homeostasis but also regulate inflammation. TIPE2 mainly restrains the activation of T cell receptor (TCR) and Toll-like receptors (TLR), regulating its downstream signaling pathways, thereby regulating inflammation. Interestingly, TIPE2 is abnormally expressed in many inflammatory diseases and may promote or inhibit inflammation in different diseases. This review summarizes the molecular target and cellular function of TIPE2 in immune cells and inflammatory diseases and the underlying mechanism by which TIPE2 regulates inflammation. The function and mechanism of TIPE2 in asthma is also explained in detail. TIPE2 is abnormally expressed in asthma and participates in the pathogenesis of different phenotypes of asthma through regulating multiple inflammatory cells' activity and function. Considering the indispensable role of TIPE2 in asthma, TIPE2 may be an effective therapeutic target in asthma. However, the available data are insufficient to provide a full understanding of the complex role of TIPE2 in human asthma. Further study is still necessary to explore the possible mechanism and functions of TIPE2 in different asthma phenotypes.

Matrix Metalloproteinases as Potential Biomarkers and Therapeutic Targets in Liver Diseases

Chronic liver diseases, characterized by an excessive accumulation of extracellular matrix (ECM) resulting in scar tissue formation, are a growing health problem causing increasing morbidity and mortality worldwide. Currently, therapeutic options for tissue fibrosis are severely limited, and organ transplantation is the only treatment for the end-stage liver diseases. During liver damage, injured hepatocytes release proinflammatory factors resulting in the recruitment and activation of immune cells that activate quiescent hepatic stellate cells (HSCs). Upon activation, HSCs transdifferentiate into highly proliferative, migratory, contractile and ECM-producing myofibroblasts. The disrupted balance between ECM deposition and degradation leads to the formation of scar tissue referred to as fibrosis. This balance can be restored either by reducing ECM deposition (by inhibition of HSCs activation and proliferation) or enhancing ECM degradation (by increased expression of matrix metalloproteinases (MMPs)). MMPs play an important role in ECM remodeling and represent an interesting target for therapeutic drug discovery. In this review, we present the current knowledge about ECM remodeling and role of the different MMPs in liver diseases. MMP expression patterns in different stages of liver diseases have also been reviewed to determine their role as biomarkers. Finally, we highlight MMPs as promising therapeutic targets for the resolution of liver diseases.

Immune Negative Regulator TIPE2 Inhibits Cervical Squamous Cancer Progression Through Erk1/2 Signaling

Tumor necrosis factor (TNF)-α-induced protein-8-like 2, or TIPE2, is a newly found immune negative regulatory molecule. This study further investigated the role of TIPE2 on proliferation and invasion of cervical squamous cancer cells. Expression of TIPE2 was compared in cervical squamous cancer tissues and adjacent normal tissues by Western blot and immunohistochemistry (IHC). Cervical squamous cancer cell lines, SiHa and C33A, were transfected with recombinant plasmid encoding TIPE2 and tested for cytologic characteristics. The impact of TIPE2 on phosphorylation of extracellular signal-regulated kinase (Erk) signaling pathway was also tested by Western blot analysis of key factors. TIPE2 expression was higher in cervical cancer tissues than that in normal tissue. IHC score of tumor tissue was negatively associated with lymphatic metastasis. Over expression of TIPE2 effectively inhibited the proliferation of cervical cancer cells. Wound healing and transwell assay showed that over expression of TIPE2 suppressed cell migration and invasion in vitro. Meanwhile, phosphorylation of Erk1/2 and upstream mitogen-activated protein kinase kinase (MEK) 1/2 was reduced by TIPE2. TIPE2 is negatively related with development of cervical squamous cancer. TIPE2 is an inhibitory factor of proliferation and invasion of cervical squamous cancer cells, probably through inhibiting Erk signaling pathway.

TIPE2 Induced the Proliferation, Survival, and Migration of Lung Cancer Cells Through Modulation of Akt/mTOR/NF-κB Signaling Cascade

Lung cancer represents the most common cause of cancer deaths in the world, constituting around 11.6% of all new cancer cases and 18.4% of cancer-related deaths. The propensity for early spread, lack of suitable biomarkers for early diagnosis, as well as prognosis and ineffective existing therapies, contribute to the poor survival rate of lung cancer. Therefore, there is an urgent need to develop novel biomarkers for early diagnosis and prognosis which in turn can facilitate newer therapeutic avenues for the management of this aggressive neoplasm. TIPE2 (tumor necrosis factor-α-induced protein 8-like 2), a recently identified cytoplasmic protein, possesses enormous potential in this regard. Immunohistochemical analysis showed that TIPE2 was significantly upregulated in different stages and grades of lung cancer tissues compared to normal lung tissues, implying its involvement in the positive regulation of lung cancer. Further, knockout of TIPE2 resulted in significantly reduced proliferation, survival, and migration of human lung cancer cells through modulation of the Akt/mTOR/NF-κB signaling axis. In addition, knockout of TIPE2 also caused arrest in the S phase of the cell cycle of lung cancer cells. As tobacco is the most predominant risk factor for lung cancer, we therefore evaluated the effect of TIPE2 in tobacco-mediated lung carcinogenesis as well. Our results showed that TIPE2 was involved in nicotine-, nicotine-derived nitrosamine ketone (NNK)-, N-nitrosonornicotine (NNN)-, and benzo[a]pyrene (BaP)-mediated lung cancer through inhibited proliferation, survival, and migration via modulation of nuclear factor kappa B (NF-κB)- and NF-κB-regulated gene products, which are involved in the regulation of diverse processes in lung cancer cells. Taken together, TIPE2 possesses an important role in the development and progression of lung cancer, particularly in tobacco-promoted lung cancer, and hence, specific targeting of it holds an enormous prospect in newer therapeutic interventions in lung cancer. However, these findings need to be validated in the in vivo and clinical settings to fully establish the diagnostic and prognostic importance of TIPE2 against lung cancer.

Tumor necrosis factor-α-induced protein 8-like 2 mRNA in peripheral blood mononuclear cells is associated with the disease progression of chronic hepatitis B virus infection

BACKGROUND

Tumor necrosis factor-alpha-induced protein 8-like 2 (TIPE2) is a novel target and molecule in the negative regulation of immune homeostasis. The present study aimed to investigate the dynamic expression of TIPE2 mRNA during the progression of chronic hepatitis B virus (HBV) infection.

METHODS

A total of 193 patients with chronic HBV infection were retrospectively recruited into this cross-sectional study, including 97 patients with chronic hepatitis B (CHB), 55 with liver cirrhosis and 41 with HBV-related hepatocellular carcinoma (HCC). TIPE2 mRNA was determined using real-time quantitative polymerase chain reaction.

RESULTS

The expression of TIPE2 levels in patients with HCC was significantly decreased compared with expression in patients with liver cirrhosis, CHB and healthy controls (P < 0.05); meanwhile, the TIPE2 mRNA levels in patients with CHB and liver cirrhosis were significantly increased compared with levels in healthy controls (P < 0.01). In liver cirrhosis, the TIPE2 mRNA level in the decompensated state was significantly higher than that in the compensated state (P < 0.05). In HCC patients, TIPE2 mRNA was significantly associated with venous invasion, tumor size and tumor node metastasis stage. Furthermore, the optimal cutoff of 0.78 for the level of TIPE2 mRNA has a sensitivity of 97.56% and a specificity of 88.16% for discriminating HCC from patients with CHB and liver cirrhosis.

CONCLUSIONS

TIPE2 mRNA was associated with various stages of chronic HBV infection, ranging from CHB to liver cirrhosis and HCC. Furthermore, TIPE2 mRNA with an optional cutoff value of 0.78 might serve as a promising biomarker to discriminate HBV-associated HCC from CHB and LC patients.

TNF-α derived from M2 tumor-associated macrophages promotes epithelial-mesenchymal transition and cancer stemness through the Wnt/β-catenin pathway in SMMC-7721 hepatocellular carcinoma cells

M2-polarized tumor-associated macrophages (M2-TAMs) infiltrating the tumor microenvironment contribute to hepatocellular carcinoma (HCC) progression. It was reported that cancer cells undergoing EMT will acquire stemness characteristics. Here, the HCC SMMC-7721 cell line was co-cultured with M2-TAMs polarized from THP-1 cells in vitro. In in vivo studies, we used nude mice subcutaneous tumor model to test whether the growth of the tumor was affected by M2-TAMs. Subsequently, EMT, stemness and Wnt/β-catenin pathway related markers were detected in cells and subcutaneous tumor tissues. TNF-α was also assessed in both the co-culture system supernatants and in nude mice serum. We found that SMMC-7721 underwent EMT and acquired stemness after co-culture with M2-TAMs, and resulted in larger tumor size following subcutaneous injection of SMMC-7721 suspended in M2-TAMs supernatants compared with SMMC-7721 alone. Enzyme linked immunosorbent assay showed that TNF-α expression was elevated in supernatants of M2-TAMs and positively correlated with tumor size in the serum of nude mice. Furthermore, we found that the Wnt/β-catenin pathway was a downstream target of TNF-α and that the Wnt/β-catenin inhibitor ICG-001 partially reversed EMT and attenuated cancer stemness. Our results indicate that TNF-α derived from M2-TAMs promote EMT and cancer stemness cells via the Wnt/β-catenin pathway.

Correlation of serum levels and gene expression of tumor necrosis factor-α-induced protein-8 like-2 with Parkinson disease severity

Different immune-mediated mechanisms involved in the pathogenesis of Parkinson disease (PD) as a neurodegenerative and inflammatory disease. According to our knowledge, there is no report evaluating Tumor necrosis factor-α-induced protein-8 like-2 (TIPE2), a cytokine maintaining immune homeostasis, in PD. We analyzed the correlation of the serum levels and circulatory gene expression of TIPE2 with severity of PD. In this case-control study, 43 patients with PD and 40 healthy subjects were enrolled. The diagnosis of PD was performed byclinical diagnostic criteria of the UK Parkinson's Disease Society Brain Bank. The severity of PD was evaluated by modified Hoehn and Yahr (H and Y) scale. Serum levels and gene expression of TIPE2 were assessed by Elisa and real time PCR, respectively. The mean serum levels and gene expression of TIPE2 in patients with PD did not have significant difference compared to healthy subjects. Linear multiple regression analysis showed that increased serum levels of TIPE2 are positively related to age and severity of PD (P ≤ 0.0001). In addition, the gene expression of TIPE2 was found to be associated with age (P < 0.0001). Our study showed that the serum levels of TIPE2 and its gene expression might be important prognostic biomarkers of PD.

TIPE Family of Proteins and Its Implications in Different Chronic Diseases

The tumor necrosis factor-α-induced protein 8-like (TIPE/TNFAIP8) family is a recently identified family of proteins that is strongly associated with the regulation of immunity and tumorigenesis. This family is comprised of four members, namely, tumor necrosis factor-α-induced protein 8 (TIPE/TNFAIP8), tumor necrosis factor-α-induced protein 8-like 1 (TIPE1/TNFAIP8L1), tumor necrosis factor-α-induced protein 8-like 2 (TIPE2/TNFAIP8L2), and tumor necrosis factor-α-induced protein 8-like 3 (TIPE3/TNFAIP8L3). Although the proteins of this family were initially described as regulators of tumorigenesis, inflammation, and cell death, they are also found to be involved in the regulation of autophagy and the transfer of lipid secondary messengers, besides contributing to immune function and homeostasis. Interestingly, despite the existence of a significant sequence homology among the four members of this family, they are involved in different biological activities and also exhibit remarkable variability of expression. Furthermore, this family of proteins is highly deregulated in different human cancers and various chronic diseases. This review summarizes the vivid role of the TIPE family of proteins and its association with various signaling cascades in diverse chronic diseases.

Combination of a Latency-Reversing Agent With a Smac Mimetic Minimizes Secondary HIV-1 Infection in vitro

Latency-reversing agents (LRAs) are considered a potential tool to cure human immunodeficiency virus type 1 (HIV-1) infection, but when they are taken alone, virus production by reactivated cells and subsequent infection will occur. Hence, it is crucial to simultaneously take appropriate measures to prevent such secondary HIV-1 infection. In this regard, a strategy to minimize the production of infectious viruses from LRA-reactivated cells is worth pursuing. Here, we focused on a second mitochondria-derived activator of caspases (Smac) mimetic, birinapant, to induce apoptosis in latent HIV-1-infected cells. When birinapant was administered alone, it only slightly increased the expression of caspase-3. However, in combination with an LRA (e.g., PEP005), it strongly induced the expression of caspase-3 followed by enhanced apoptosis. Importantly, the combination eliminated reactivated cells and drastically reduced HIV-1 production. Finally, we found that birinapant decreased the mRNA expression of HIV-1 that was induced by PEP005 in the primary CD4⁺ T-cells from HIV-1-carrying patients as well. These results suggest that the combination of an LRA and an “apoptosis-inducing” agent, such as a Smac mimetic, is a possible treatment option to decrease HIV-1 reservoirs without the occurrence of HIV-1 production by reactivated cells.

TIPE2 sensitizes osteosarcoma cells to cis-platin by down-regulating MDR1 via the TAK1- NF-κB and - AP-1 pathways

TIPE2 participates in multiple types of cancer development. However, its mechanism underlying chemoresistance in osteosarcoma has not been elucidated. Herein, we observed the expression of TIPE2 and MDR1 in cis-platin-resistant osteosarcoma tissues and cell lines. Compared to their matched sensitive cell lines and tissues, TIPE2 was downregulated while MDR1 expression was increased. Further investigation showed that overexpression of TIPE2 effectively inhibited MDR1 expression and greatly sensitized osteosarcoma cells to cis-platin, both in vivo and in vitro. Mechanistically, TIPE2 inhibited the transcription of the MDR1 promoter by interfering with the TAK1-NF-κB and -AP-1 pathways. Overall, our results elucidated for the first time that TIPE2 sensitizes osteosarcoma cells to cis-platin through downregulation of MDR1 and may be a novel target in osteosarcoma therapy.

Tumor-associated macrophage-derived cytokines enhance cancer stem-like characteristics through epithelial-mesenchymal transition

Cancer stem cells are a small population of cells with the potential for self-renewal and multi-directional differentiation and are an important source of cancer initiation, treatment resistance, and recurrence. Epithelial-mesenchymal transition (EMT) is a process in which epithelial cells lose their epithelial phenotype and convert to mesenchymal cells. Recent studies have shown that cancer cells undergoing EMT can become stem-like cells. Many kinds of tumors are associated with chronic inflammation, which plays a role in tumor progression. Among the various immune cells mediating chronic inflammation, macrophages account for ~30%-50% of the tumor mass. Macrophages are highly infiltrative in the tumor microenvironment and secrete a series of inflammatory factors and cytokines, such as transforming growth factor (TGF)-β, IL-6, IL-10, and tumor necrosis factor (TNF)-α, which promote EMT and enhance the stemness of cancer cells. This review summarizes and discusses recent research findings on some specific mechanisms of tumor-associated macrophage-derived cytokines in EMT and cancer stemness transition, which are emerging targets of cancer treatment.

Ataxia-telangiectasia mutated activation mediates tumor necrosis factor-alpha induced MMP-13 up-regulation and metastasis in lung cancer cells

Despite that ataxia-telangiectasia mutated (ATM) is involved in IL-6 promoted lung cancer chemotherapeutic resistance and metastasis, the exact role of ATM in tumor necrosis factor-alpha (TNF-α) increasing tumor migration is still elusive. In the present study, we demonstrated that TNF-α promoted lung cancer cell migration by up-regulation of matrix metalloproteinase-13 (MMP-13). Notably, by gene silencing or kinase inhibition, we proposed for the first time that ATM is a key up-stream regulator of TNF-α activated ERK/p38-NF-κB pathway. The existence of TNF-α secreted in autocrine or paracrine manner by components of tumor microenvironment highlights the significance of TNF-α in inflammation-associated tumor metastasis. Importantly, in vivo lung cancer metastasis test showed that ATM depletion actually reduce the number of metastatic nodules and cancer nests in lung tissues, verifying the critical role of ATM in metastasis. In conclusion, our findings demonstrate that ATM, which could be activated by lung cancer-associated TNF-α, up-regulate MMP-13 expression and thereby augment tumor metastasis. Therefore, ATM might be a promising target for prevention of inflammation-associated lung cancer metastasis.

TIPE‑2 suppresses growth and aggressiveness of hepatocellular carcinoma cells through downregulation of the phosphoinositide 3‑kinase/AKT signaling pathway

Rapid proliferation and migration are the main features of hepatocellular carcinoma (HCC) cells, which serve an essential role in carcinogenesis and are a hallmark of cancer therapy resistance. Previous studies have reported that tumor necrosis factor-α-induced protein-8 like-2 (TIPE-2) is involved in cancer initiation and the progression of HCC. The present study aimed to clarify the role of TIPE-2 in HCC carcinogenesis, growth and aggressiveness. The effects of TIPE-2 on HCC were determined using colony forming and cell cycle analyses. Cell apoptosis, and growth and aggressiveness of HCC cells, were investigated following TIPE-2 treatment. Treatment with TIPE-2 markedly suppressed HCC cell proliferation and increased the number of cells in S phase of the cell cycle. The results demonstrated that TIPE-2 significantly inhibited growth, migration and invasion of HCC cells via the downregulation of tumor metastasis-associated genes. Flow cytometric analysis indicated that TIPE-2 promoted apoptosis of HCC cells via regulation of apoptosis-associated gene transcription. In addition, TIPE-2 administration downregulated the expression of phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT) in HCC cells. In addition, TIPE-2 selectively decreased neuroblastoma Ras viral oncogene and p27 expression in HCC cells. In vivo assays revealed that TIPE-2 significantly inhibited tumor growth and prolonged animal survival by promoting apoptosis of tumor cells. The results of the present study indicated that TIPE-2 acts as an inhibitor of HCC cell growth and aggressiveness, and promotes apoptosis, thus suggesting that TIPE-2 may inhibit the metastasis-associated PI3K/AKT signaling cascade and may arrest the tumor cell cycle. These findings provide a potential molecular mechanism by which TIPE-2 promotes apoptosis of HCC cells.

A novel TNFAIP8 gene mediates l-arginine metabolism in Apostichopus japonicus

Tumor necrosis factor (TNF)-α-induced protein 8 (TNFAIP8) family is a newly identified protein with vital roles in maintaining immune homeostasis. In the current study, we first cloned and characterized a TNFAIP8 gene from the invertebrate sea cucumber Apostichopus japonicus. The gene was designated as AjTNFAIP8. The full-length cDNA of AjTNFAIP8 was 1455 bp long and encoded a matured protein of 201 amino acid residues. Structural analysis indicated that AjTNFAIP8 had a death effector domain (DED)-like domain and composed of six α-helices. Multiple sequence alignment and phylogenetic analysis supported that AjTNFAIP8 is a new member of the TNFAIP8 family. Analysis of basal transcription in five tissues revealed the constitutive expression of AjTNFAIP8 in the detected tissues with highest expression in the respiratory tree and minimum expression in the tentacle. Vibrio splendidus infection and LPS stimulation could significantly downregulate the mRNA expression of AjTNFAIP8. More importantly, the transcription of pro-inflammatory molecule NOS and its production of NO content were significantly increased after AjTNFAIP8 silencing, with the suppression of agmatinase transcript and arginase activity. These results clearly indicated that AjTNFAIP8 is an essential negative regulator in innate immunity. Basic information for further exploration of the functional mechanisms of TNFAIP8 family in other marine invertebrate is provided.

Stable silencing of TIPE2 reduced the Poly I:C‑induced apoptosis in THP‑1 cells

The present study aimed to determine the underlying mechanism of toll‑like receptor (TLR) agonist polyinosinic:polycytidylic acid (Poly I:C)‑induced apoptosis in THP‑1 cells following silencing the expression of tumor necrosis factor α‑induced protein 8‑like 2 (TIPE2). THP‑1 cells were incubated with different concentrations of the TLR agonist. Following incubation, reverse transcription‑quantitative polymerase chain reaction was performed to quantify the mRNA expression of TIPE2. Lentiviral technology was used to silence the expression of TIPE2. MTT assay was performed to assess cell proliferation, Annexin V/PI double staining was used to evaluate the apoptosis and western blotting was used to determine the expression levels of caspase‑8 following TIPE2 silencing. The TLRs agonist Poly I:C increased the expression level of TIPE2. During the incubation, Poly I:C also inhibited the proliferation of THP‑1 cells and induced apoptosis. Following silencing of TIPE2 in THP‑1 cells, the Poly I:C‑induced TIPE2 expression was significantly downregulated. Additionally, the Poly I:C‑induced proliferation inhibition and apoptosis in THP‑1 cells were significantly reduced following silencing of TIPE2. The findings of the western blot analysis indicated that the active form of caspase‑8, p18, was downregulated following silencing of TIPE2. In conclusion, the expression of TIPE2 in THP‑1 cells may be upregulated by Poly I:C, which may also inhibit cell proliferation and induce apoptosis. Following the downregulation of TIPE2 the aforementioned effect of Poly I:C treatment was reversed and may be associated with the reduced activity of caspase‑8 that was observed in the TIPE2 silenced group.

TIPE1 function as a prognosis predictor and negative regulator of lung cancer

TIPE1 (tumor necrosis factor-α-induced protein 8-like 1 or TNFAIP8L1) belongs to the TIPE (TNFAIP8) family, which act as a regulator of cell death. However, the expression and biologic functions of TIPE1 in lung cancer are largely unknown. Here, we investigated the roles of TIPE1 in lung cancer. Evaluated by qRT-PCR and immunohistochemical staining, lower TIPE1 mRNA and protein expression was found in the lung tumor tissue, compared with adjacent non-tumor tissues, which positively correlated with tumor patient survival. Overexpression of TIPE1 by lentivirus system in TIPE1-downregulated lung cancer cells significantly diminished cell growth and colony formation, companied with proliferation inhibition, apoptosis induction and invasion inhibition. It was identified to be due to TIPE1-regulated Cyclin D1, Cyclin B1, caspase 8, Caspase3, MM2 and MMP9 expression. Consistently, using a homograft tumor model in Balb/c mice, we discovered that TIPE1 prevented the growth and tumor weight of murine lung cancer homografts. Our findings revealed the anti-tumor role of TIPE1 in lung cancer cells and TIPE1 might be a novel prognostic indicator for lung cancer patients.

Evolutionary divergence of the vertebrate TNFAIP8 gene family: Applying the spotted gar orthology bridge to understand ohnolog loss in teleosts

Comparative functional genomic studies require the proper identification of gene orthologs to properly exploit animal biomedical research models. To identify gene orthologs, comprehensive, conserved gene synteny analyses are necessary to unwind gene histories that are convoluted by two rounds of early vertebrate genome duplication, and in the case of the teleosts, a third round, the teleost genome duplication (TGD). Recently, the genome of the spotted gar, a holostean outgroup to the teleosts that did not undergo this third genome duplication, was sequenced and applied as an orthology bridge to facilitate the identification of teleost orthologs to human genes and to enhance the power of teleosts as biomedical models. In this study, we apply the spotted gar orthology bridge to help describe the gene history of the vertebrate TNFAIP8 family. Members of the TNFAIP8 gene family have been linked to regulation of immune function and homeostasis and the development of multiple cancer types. Through a conserved gene synteny analysis, we identified zebrafish orthologs to human TNFAIP8L1 and TNFAIP8L3 genes and two co-orthologs to human TNFAIP8L2, but failed to identify an ortholog to human TNFAIP8. Through the application of the orthology bridge, we determined that teleost orthologs to human TNFAIP8 genes were likely lost in a genome inversion event after their divergence from their common ancestor with spotted gar. These findings demonstrate the value of this enhanced approach to gene history analysis and support the development of teleost models to study complex questions related to an array of biomedical issues, including immunity and cancer.

TIPE2 Overexpression Suppresses the Proliferation, Migration, and Invasion in Prostate Cancer Cells by Inhibiting PI3K/Akt Signaling Pathway

Tumor necrosis factor-α (TNF-α)-induced protein 8-like 2 (TNFAIP8L2, TIPE2) is involved in the invasion and metastasis of human tumors. However, the functional role of TIPE2 in prostate cancer remains unclear. In the present study, we explored the role of TIPE2 in prostate cancer and cancer progression including the molecular mechanism that drives TIPE2-mediated oncogenesis. Our results showed that TIPE2 was lowly expressed in human prostate cancer tissues and cell lines. In addition, restored TIPE2 obviously inhibits proliferation in prostate cancer cells. TIPE2 overexpression also suppresses the epithelial–mesenchymal transition (EMT) process and migration/invasion in prostate cancer cells. Mechanistically, TIPE2 overexpression obviously inhibits the phosphorylation levels of phosphatidylinositol 3-kinase (PI3K) and Akt in prostate cancer cells. In conclusion, for the first time we demonstrated that TIPE2 overexpression may suppress proliferation, migration, and invasion in prostate cancer cells by inhibiting the PI3K/Akt signaling pathway. Therefore, TIPE2 might serve as a potential therapeutic target for human prostate cancer.

TIPE2 Inhibits Hypoxia-Induced Wnt/β-Catenin Pathway Activation and EMT in Glioma Cells

Hypoxia-induced epithelial-to-mesenchymal transition (EMT) could facilitate tumor progression. TIPE2, the tumor necrosis factor-α (TNF-α)-induced protein 8-like 2 (also known as TNFAIP8L2), is a member of the TNF-α-induced protein 8 (TNFAIP8, TIPE) family and has been involved in the development and progression of several tumors. However, the effects of TIPE2 on the EMT process in glioma cells and the underlying mechanisms of these effects have not been previously reported. In our study, we assessed the roles of TIPE2 in the EMT process in glioma cells in response to hypoxia. Our results indicated that TIPE2 expression was significantly decreased in human glioma cell lines. TIPE2 overexpression significantly inhibited hypoxia-induced migration and invasion, as well as suppressed the EMT process in glioma cells. Furthermore, TIPE2 overexpression prevented hypoxia-induced expression of β-catenin, cyclin D1, and c-myc in human glioma cells. In summary, these data suggest that TIPE2 overexpression inhibited hypoxia-induced Wnt/β-catenin pathway activation and EMT in glioma cells.

Regulation of inflammation and tumorigenesis by the TIPE family of phospholipid transfer proteins

The TIPE (tumor necrosis factor-α-induced protein 8-like) family are newly described regulators of immunity and tumorigenesis consisting of four highly homologous mammalian proteins: TNFAIP8 (tumor necrosis factor-α-induced protein 8), TIPE1 (TNFAIP8-like 1, or TNFAIP8L1), TIPE2 (TNFAIP8L2) and TIPE3 (TNFAIP8L3). They are the only known transfer proteins of the lipid secondary messengers PIP2 (phosphatidylinositol 4,5-bisphosphate) and PIP3 (phosphatidylinositol 3,4,5-trisphosphate). Cell-surface receptors, such as G-protein-coupled receptors and receptor tyrosine kinases, regulate inflammation and cancer via several signaling pathways, including the nuclear factor (NF)-κB and phosphoinositide-3 kinase (PI3K) pathways, the latter of which is upstream of both Akt and STAT3 activation. An expression analysis in humans demonstrated that the TIPE family is dysregulated in cancer and inflammation, and studies both in mice and in vitro have demonstrated that this family of proteins plays a critical role in tumorigenesis and inflammatory responses. In this review, we summarize the current literature for all four family members, with a special focus on the phenotypic manifestations present in the various knockout murine strains, as well as the related cell signaling that has been elucidated to date.

Adenovirus-mediated TIPE2 overexpression inhibits gastric cancer metastasis via reversal of epithelial-mesenchymal transition

Tumor necrosis factor (TNF)-alpha-induced protein 8-like 2 (TNFAIP8L2; also termed TIPE2) has been shown to be involved in both the immune-negative modulation and cancer. We previously found that TIPE2 is lost in human gastric cancer, and TIPE2 restoration suppresses gastric cancer growth by induction of apoptosis and impairment of protein kinase B (PKB/AKT) and extracellular signal-regulated kinase-1/2 (ERK1/2) signaling. However, its correlation with epithelial-mesenchymal transition (EMT) in gastric cancer is largely elusive. In the present report, we carried out a gain-of-function study in AGS and HGC-27 human gastric cancer cells by adenovirus-mediated human TIPE2 gene transfer (AdVTIPE2). We then examined the effects of AdVTIPE2 on in vitro migration and invasion of AGS and HGC-27 tumor cells by wound-healing assay and Transwell invasion assay, respectively. We also investigated the effects of AdVTIPE2 on in vivo lung metastasis of AGS and HGC-27 tumor cells by intravenous (i.v.) injection in athymic BALB/c nude mice. We demonstrated that AdVTIPE2 remarkably suppressed the migratory, invasive and metastatic potential of AGS and HGC-27 tumor cells in vitro and in vivo in BALB/c nude mouse model. Mechanistically, AdVTIPE2 obviously upregulated E-cadherin epithelial marker in AGS and HGC-27 tumor cells, whereas it downregulated N-cadherin and Vimentin mesenchymal markers, Snail1, Snail2/Slug and Zeb1 EMT-inducing transcription factors (EMT-TFs), and tripartite motif-containing 29 (TRIM29) and phosphatase regenerating liver 3 (PRL-3) gastric cancer-specific metastasis markers. Importantly, glycogen synthase kinase-3β (GSK-3β) inhibitor VIII and 26S proteasome inhibitor MG132 assays revealed that TIPE2 downregulated Snail1 and Snail2/Slug in a GSK-3β- and proteasome-dependent manner possibly by impairing AKT signaling. Our data provided the first evidence that TIPE2 inhibits gastric cancer cell migration, invasion and metastasis very probably via reversal of EMT, revealing that TIPE2 may be a novel therapeutic target for human gastric cancer EMT and metastasis.

Expression and roles of TIPE2 in autoimmune hepatitis

Tumor necrosis factor, alpha-induced protein 8-like 2 (TIPE2) is associated with the development of hepatic inflammatory diseases. However, to date, the possible role of TIPE2 in autoimmune hepatitis (AIH) has not been reported. The present study aimed to investigate the expression of TIPE2 in peripheral blood mononuclear cells (PBMCs) of mice with AIH. Furthermore, the liver function, pro-inflammatory cytokine production and hepatic histopathology were examined in TIPE2-deficient mice in order to evaluate whether TIPE2 is involved in the pathogenesis of AIH. A murine model of AIH was induced by treatment with concanavalin A (ConA). The expression of TIPE family members in the PBMCs was examined using reverse-transcription quantitative polymerase chain reaction analysis, while the protein expression of TIPE2 was additionally detected by western blot analysis. The activity of alanine amiotransferase (ALT) and aspartate aminotransferase (AST) in the serum was measured on an automated chemical analyzer to assess liver function. The serum levels of tumor necrosis factor-α, interleukin (IL)-6 and IL-12 were measured using commercial ELISA kits. Hematoxylin and eosin staining was performed to assess hepatic histopathology. The results showed that the expression of TIPE2 was significantly decreased in the mice with AIH. Following ConA-induced AIH, TIPE2-deficient mice had significantly increased serum ALT and AST levels, enhanced production of pro-inflammatory cytokines, as well as more severe hepatic inflammation compared with the wild-type mice. In conclusion, the present study demonstrated, for the first time, that TIPE2 is involved in the pathogenesis of AIH. TIPE2 prevents liver dysfunction and inhibits deleterious inflammatory immune responses after AIH and may therefore serve as a novel agent for the treatment of AIH.

Analysis of esophageal cancer cell lines exposed to X-ray based on radiosensitivity influence by tumor necrosis factor-α

Assess the effects of tumor necrosis factor-α (TNF-α) in enhancing the radiosensitivity of esophageal cancer cell line in vitro. Three esophageal cancer cell line cells were exposed to X-ray with or without TNF-α treatment. MTT assay was used to evaluate the cell growth curve, and flow cytometry was performed to assess the cell apoptosis. The radiosensitizing effects of TNF-α were detected by cell colony formation assay. Western blotting was applied to observe the expression of NF-κB and caspase-3 protein in the exposed cells. Our results indicated that cellular inhibition rate increased over time, the strongest is combined group (P < 0.05). Western blotting showed that the decline expression of NF-κB protein was stated between only rhTNF-α and only X-ray radiation group and the maximum degree was manifested in combined group. Caspase-3 protein content expression just works opposite. Three kinds of cells in the NF-κB protein were similar without rhTNF-α. Then SEG1 NF-κB protein content was reduced more than other two kinds. We concluded that the cells treated with TNF-α showed significantly suppressed cell proliferation, increasing the cell apoptosis, and caspase-3 protein expression after X-ray exposure. TNF-α can enhance the radiosensitivity of esophageal cancer to enhancing the effect of the former.

Hepatitis C virus promotes hepatocellular carcinogenesis by targeting TIPE2, a new regulator of DNA damage response

Infection of hepatitis C virus (HCV) is associated with primary hepatocellular carcinoma (HCC). However, its underlying molecular mechanisms remain enigmatic. Tumor necrosis factor-α-induced protein 8-like 2 (TIPE2), a new negative regulator of immunity, plays significant roles in modulating inflammation and tumorigenesis. We hypothesized that TIPE2 might be involved in the development of HCV-induced HCC. To test this hypothesis, the expression of TIPE2 was determined by Western blot in the tumor and pericarcinomatous tissues collected from ten HCV-positive HCC patients; the interaction between TIPE2 and HCV-encoded non-structural proteins was analyzed by immunoprecipitation and immunofluorescence assays, and tumorigenesis and its mechanisms were studied in cell models and nude mice. Our results demonstrated that the expression of TIPE2 was significantly reduced in HCC tissues compared to that in the paracarcinoma tissues. HCV-encoded non-structural protein NS5A could specifically interact with TIPE2 and induce its degradation. Downregulation of TIPE2 by shRNA in cell lines increased genomic DNA damage and promoted cell colony formation in vitro and tumorigenesis in nude mice. In contrast, overexpression of TIPE2 had an opposite effect. Downregulation of TIPE2 by NS5A is associated with genomic DNA instability and HCV-induced HCC development. Thus, TIPE2 may be a new therapeutic target for the treatment of HCV-associated HCC.

Adenovirus-directed expression of TIPE2 suppresses gastric cancer growth via induction of apoptosis and inhibition of AKT and ERK1/2 signaling

Tumor necrosis factor (TNF)-α-induced protein 8-like 2 (TNFAIP8L2/TIPE2) as a novel anti-inflammatory factor plays an important role in maintaining immune homeostasis. Recently, TIPE2 has been shown to inhibit hepatocarcinoma growth and metastasis through targeting Ras and Rac1. However, its effects in human cancers are poorly understood. In the present study, we analyzed TIPE2 mRNA expression in a panel of human gastric cancer cells (AGS, HGC-27 and SGC-7901) and then examined the cell-autonomous effects of adenovirus-mediated human TIPE2 gene transfer (AdVTIPE2) on AGS and HGC-27 human gastric cancer cells. We found that compared with the GES-1 normal human gastric mucous epithelial cells, human TIPE2 was lost in the AGS, HGC-27 and SGC-7901 gastric cancer cells. Adenovirus-mediated human TIPE2 overexpression significantly inhibited AGS and HGC-27 gastric cancer cell growth and induced AGS and HGC-27 tumor cell apoptosis in vitro. Furthermore, AdVTIPE2 treatment obviously suppressed the growth of AGS gastric cancer subcutaneously xenografted tumors implanted in athymic BALB/c nude mice in vivo. Mechanistically, AdVTIPE2 exhibited marked effects on the upregulation of Bax, cleaved Caspase-9, cleaved Caspase-3, cleaved poly ADP ribose polymerase as well as the downregulation of B-cell lymphoma (Bcl)-XL, phosphorylated-protein kinase B (p-PKB/AKT), phosphorylated-extracellular signal-regulated kinase 1/2 (p-ERK1/2) in AGS gastric cancer cells in vitro and in vivo. Collectively, AdVTIPE2 suppressed gastric cancer growth very possibly by the activation of intrinsic apoptotic pathway and the attenuation of AKT and ERK1/2 signaling. Thus, our data indicated that TIPE2 may be a novel potential therapeutic target for human gastric cancer.

Interleukin 6 trigged ataxia-telangiectasia mutated activation facilitates lung cancer metastasis via MMP-3/MMP-13 up-regulation

Our previous studies show that the phosphorylation of ataxia-telangiectasia mutated (ATM) induced by interleukin 6 (IL-6) treatment contributes to multidrug resistance formation in lung cancer cells, but the exact role of ATM activation in IL-6 increased metastasis is still elusive. In the present study, matrix metalloproteinase-3 (MMP-3) and MMP-13 were firstly demonstrated to be involved in IL-6 correlated cell migration. Secondly, IL-6 treatment not only increased MMP-3/MMP-13 expression but also augmented its activities. Thirdly, the inhibition of ATM phosphorylation efficiently abolished IL-6 up-regulating MMP-3/MMP-13 expression and increasing abilities of cell migration. Most importantly, the in vivo test showed that the inhibition of ATM abrogate the effect of IL-6 on lung cancer metastasis via MMP-3/MMP-13 down-regulation. Taken together, these findings demonstrate that IL-6 inducing ATM phosphorylation increases the expression of MMP-3/MMP-13, augments the abilities of cell migration, and promotes lung cancer metastasis, indicating that ATM is a potential target molecule to overcome IL-6 correlated lung cancer metastasis.

Paeoniflorin induces HepG2 cell apoptosis by regulating Caspase3 activation and nuclear factor kappa B signaling pathway

AIM: To explore the effect of paeoniflorin on apoptosis of HepG2 cells and the underlying mechanisms.

METHODS: HepG2 cells were treated with different concentrations of paeoniflorin (0.5, 1.0, and 2.0 mg/mL). The viability of cells was detected by MTT assay. Apoptotic cells were detected by Annexin V-FITC flow cytometry. Caspase3 activity was measured with a colorimetric assay kit. The expression of nuclear factor kappa-B (NF-κB) related proteins was detected by Western blot.

RESULTS: Compared with the control group, paeoniflorin at concentrations of 0.5, 1.0, and 2.0 mg/mL could reduce cell viability, and the inhibitory rate peaked at 48 h (P < 0.05). Compared with the control group, paeoniflorin at concentrations of 0.5, 1.0, and 2.0 mg/mL could promote cell apoptosis, increase Caspase3 activity, and suppress NF-κB p65 phosphorylation (P < 0.05). Paeoniflorin at concentrations of 1.0 and 2.0 mg/mL could suppress IκBα phosphorylation (P < 0.05).

CONCLUSION: Paeoniflorin induces apoptosis of HepG2 cells possibly via the NF-κB signal pathway.

In Silico Analysis of Tumor Necrosis Factor α-Induced Protein 8-Like-1 (TIPE1) Protein

Tumor necrosis factor α-induced protein 8 (TNFAIP8)-like protein 1 (TIPE1) was a member of TNFAIP8 family. Previous studies have shown that TIPE1 could induce apoptosis in hepatocellular carcinoma. In this study, we attempted to predict its potential structure. Bioinformatic analysis of TIPE1 was performed to predict its potential structure using the bioinfomatic web services or softwares. The results showed that the amino acid sequences of TIPE1 were well conserved in mammals. No signal peptide and no transmembrane domain existed in human TIPE1. The aliphatic index of TIPE1 was 100.75 and the theoretical pI was 9.57. TIPE1 was a kind of stable protein and its grand average of hydropathicity was -0.108. Various post-translational modifications were also speculated to exist in TIPE1. In addition, the results of Swiss-Model Server and Swiss-Pdb Viewer program revealed that the predicted three-dimensional structure of TIPE1 protein was stable and it may accord with the rule of stereochemistry. TIPE1 was predicted to interact with FBXW5, caspase8 and so on. In conclusion, TIPE1 may be a stable protein with no signal peptide and no transmembrane domain. The bioinformatic analysis of TIPE1 will provide the basis for the further study on the function of TIPE1.

MiR-21: an environmental driver of malignant melanoma?

Since the mid-1950’s, melanoma incidence has been rising steadily in industrialized Caucasian populations, thereby pointing to the pivotal involvement of environmental factors in melanomagenesis. Recent evidence underlines the crucial role of microRNA (miR) signaling in cancer initiation and progression. Increased miR-21 expression has been observed during the transition from a benign melanocytic lesion to malignant melanoma, exhibiting highest expression of miR-21. Notably, common BRAF and NRAS mutations in cutaneous melanoma are associated with increased miR-21 expression. MiR-21 is an oncomiR that affects critical target genes of malignant melanoma, resulting in sustained proliferation (PTEN, PI3K, Sprouty, PDCD4, FOXO1, TIPE2, p53, cyclin D1), evasion from apoptosis (FOXO1, FBXO11, APAF1, TIMP3, TIPE2), genetic instability (MSH2, FBXO11, hTERT), increased oxidative stress (FOXO1), angiogenesis (PTEN, HIF1α, TIMP3), invasion and metastasis (APAF1, PTEN, PDCD4, TIMP3). The purpose of this review is to provide translational evidence for major environmental and individual factors that increase the risk of melanoma, such as UV irradiation, chemical noxes, air pollution, smoking, chronic inflammation, Western nutrition, obesity, sedentary lifestyle and higher age, which are associated with increased miR-21 signaling. Exosomal miR-21 induced by extrinsic and intrinsic stimuli may be superimposed on mutation-induced miR-21 pathways of melanoma cells. Thus, oncogenic miR-21 signaling may be the converging point of intrinsic and extrinsic stimuli driving melanomagenesis. Future strategies of melanoma treatment and prevention should thus aim at reducing the burden of miR-21 signal transduction.

Downregulated TIPE2 is associated with poor prognosis and promotes cell proliferation in non-small cell lung cancer

The present study aims to investigate the expression pattern of TIPE2 protein and its clinical significance in human non-small cell lung cancer (NSCLC). We investigated the expression levels of TIPE2 in 96 NSCLC tumor samples by immunohistochemistry and then analyzed its clinical significance. Furthermore, the role of TIPE2 on the biological properties of the NSCLC cell line H1299 and A549 was experimentally tested in vitro and in vivo. We found that the expression level of TIPE2 was significantly higher in normal lung tissues compared with NSCLC tissues (P<0.001), and TIPE2 downregulation was significantly correlated with advanced TNM stage (P=0.006). TIPE2 expression was lower in lung cancer cell lines than normal bronchial cell line HBE. Transfection of TIPE2 plasmid was performed in H1299 and A549 cells. TIPE2 overexpression inhibited lung cancer cell proliferation, colony formation and cell invasive in vitro, and prevented lung tumor growth in vivo. In addition, TIPE2 transfection reduced the anti-apoptotic Bcl-XL protein and mesenchymal marker N-cadherin expression. Taken together, our results demonstrate that TIPE2 might serve as a tumor suppressor in NSCLC progression.