The expression of TIPE1 in murine tissues and human cell lines

Research progress of TIPE2 in immune-related diseases

The tumor necrosis factor α-induced protein 8 (TNFAIP8) family, which consists of TNFAIP8 (TIPE), TNFAIP8L1 (TIPE1), TNFAIP8L2 (TIPE2) and TNFAIP8L3 (TIPE3), has recently emerged as a regulatory factor involved in immune response and tumorigenesis. Among its members, TIPE2 acts as a negative regulator of both innate and adaptive immunity, playing a crucial role in maintaining immune homeostasis by negatively regulating T cell receptor (TCR) and toll-like receptor (TLR) signal transduction. Immune homeostasis is an indispensable characteristic of the immune system, which prevents harmful inflammatory reactions and ensures the proper functioning of the body. A large number of studies have shown that abnormal TIPE2 expression exists in a variety of inflammation-related diseases such as asthma, colitis, and systemic lupus erythematosus, highlighting the importance of comprehending its function for the prevention and treatment of immune-related conditions. This review aims to provide an overview of the in vivo distribution and expression of TIPE2, its regulatory role in central and peripheral immune-related diseases, and the underlying mechanisms that govern its function in the inflammatory response. By delving into these aspects, a deeper understanding of the role and functionality of TIPE2 in inflammatory responses can be achieved.

Structural insight into TIPE1 functioning as a lipid transfer protein

As a member of the tumor necrosis factor-α-induced protein 8 (TNFAIP8/TIPE) family, TIPE1 has been found to be associated with many cellular signaling pathways in regulating apoptosis, autophagy, and tumorigenesis. However, the position of TIPE1 in the signaling network remains elusive. Here we present the crystal structure of zebrafish TIPE1 in complex with phosphatidylethanolamine (PE) at a resolution of 1.38 Å. By comparison with structures of other three TIPE family proteins, a universal phospholipid-binding mode was proposed. Namely, the hydrophobic cavity binds to fatty acid tails, while 'X-R-R' triad nearby the entrance of cavity recognizes the phosphate group head. Using molecular dynamics (MD) simulations, we further elaborated the mechanism of how the lysine-rich N-terminal domain assisting TIPE1 to favorably bind to phosphatidylinositol (PI). Beside small molecule substrate, we identified Gαi3 as a direct-binding partner of TIPE1 using GST pull-down assay and size-exclusion chromatography. Analyses of key-residue mutations and predicted complex structure revealed that the binding mode of TIPE1 to Gαi3 could be non-canonical. In summary, our findings narrowed down TIPE1's position in Gαi3-related and PI-inducing signaling pathways.Communicated by Ramaswamy H. Sarma.

Tumor necrosis factor-α-inducible protein 8-like protein 3 (TIPE3): a novel prognostic factor in colorectal cancer

BACKGROUND

To explore the correlation of tumor necrosis factor-α-induced protein 8-like protein 3 (TIPE3) expressions in colorectal cancer (CRC) with tumor-immune infiltration and patient prognosis.

METHODS

Formalin-fixed paraffin-embedded tumor samples from CRC patients (n = 110) were used in this study. Immunohistochemistry staining of TIPE3 and three prognostic immune biomarkers (CD8, CD20, and CD66b) was conducted in the tumor tissues and adjacent normal tissues. A Cox regression analysis of univariate and multivariate variables was performed to assess the correlation between TIPE3 and patient prognosis.

RESULT

We found that TIPE3 was mainly expressed in the cytoplasm, with a small amount in the nucleus. The expression of TIPE3 in tumor tissues is significantly higher than in adjacent normal tissues, and it is significantly correlated with the survival rate of patients in tumor tissues (p = 0.0038) and adjacent normal tissues (p<0.0001). Patients with a high TIPE3 expression had a lower survival rate, while patients with a low TIPE3 expression had a higher survival rate. Univariate regression analysis showed that the TIPE3 expression in tumor tissues (p = 0.007), the TIPE3 expression in adjacent normal tissues (p<0.001), the number of CD8+ T cells in tumor tissues (p = 0.020), the number of CD20+ B cells in tumor tissues (p = 0.023), the number of CD20+ B cells in adjacent normal tissues (p = 0.023), the number of CD66b+ neutrophils in tumor tissues (p = 0.005), the number of CD66b+ neutrophils in adjacent normal tissues (p<0.001), lymphatic metastasis (p = 0.010), TNM stage (p = 0.013), and tumor grade (p = 0.027) were significantly correlated with overall survival (OS). These prognostic factors were then subjected to multivariate regression analysis, and the results showed that the expression of TIPE3, the number of CD8+ T cells, and the number of CD66b+ neutrophils were prognostic factors affecting the OS rate of CRC patients.

CONCLUSION

We found that the TIPE3 protein is upregulated in CRC cancer tissues and is correlated with survival rate.

TIPE1 promotes liver regeneration by enhancing ROS-FoxO1 axis mediated autophagy

The strong regenerative ability of the liver safeguards the crucial hepatic functions. The balance between hepatocyte proliferation and death is critical for restoring liver size and physiology. Tumour necrosis factor (TNF) alpha-induced protein 8-like 1 (TIPE1) is highly expressed in liver and has been identified as a candidate regulator for cell proliferation and death, being involved in a variety of biological processes and diseases. However, the role of TIPE1 in liver regeneration remains unexplored. In the present study, we found that TIPE1 expression was elevated in the regenerating liver induced by either partial hepatectomy or 10% carbon tetrachloride administration. Mice with hepatocyte conditional Tipe1 knockout presented significantly impaired liver regeneration. Mechanistically, hepatic Tipe1 deficiency decreased the level of reactive oxygen species in hepatocytes, which in turn led to the inhibition of Forkhead box O1 acetylation and microtubule-associated protein 1 light chain 3 I to microtubule-associated protein 1 light chain 3 II conversion, and the accumulation of sequestosome 1. By contrast, forced expression of TIPE1 in hepatocyte significantly promoted liver regeneration following 70% partial hepatectomy and enhanced hepatocyte reactive oxygen species/acetylated-Forkhead box O1 level and autophagy. These findings indicate that TIPE1 plays a crucial role in liver regeneration by finely regulating the oxidative stress and autophagy and is a potential target for medical intervention of liver regeneration.

TIPE1 inhibits the growth of Ewing’s sarcoma cells by suppressing Wnt/β-catenin signaling

BACKGROUND

Ewing's sarcoma is the second most common bone and soft tissue malignancy in children and adolescents. Tumor necrosis factor-α-induced protein 8-like 1 (TIPE1) functions as a tumor suppressor in several cancers. Activation of Wnt/β-catenin signaling in subpopulations of tumor cells contributes to phenotypic heterogeneity and disease progression in Ewing's sarcoma. The exact role of TIPE1 in Ewing's sarcoma remains to be elucidated.

PURPOSE

This study aimed to assess the expression and function of TIPE1 in Ewing's sarcoma.

METHODS

TIPE1 expression in Ewing's sarcoma cells was determined by qPCR and western blotting. Furthermore, the Ewing's sarcoma cell line RD-ES was transfected with a lentivirus-based TIPE1 expression system to upregulate the expression of TIPE1. The Cell Counting Kit 8 was used to assess the effect of TIPE1 on cell proliferation. The effects of TIPE1 on cell migration and invasion was detected by Transwell assay. Flow cytometry was performed to detect apoptosis.

RESULTS

Our results suggested lower TIPE1 expression in Ewing's sarcoma cell lines compared with normal osseous cells. TIPE1 remarkably inhibited the growth and proliferation of Ewing's sarcoma cell; TIPE1 also induced apoptosis and inhibited invasion in vitro. TIPE1 inhibited Ewing's sarcoma growth, motility, and survival through regulation of Wnt/β-catenin signaling.

CONCLUSIONS

Our results demonstrated the anti-tumor function of TIPE1 in Ewing's sarcoma and reveal a novel therapeutic target.

TIPE1 inhibits osteosarcoma tumorigenesis and progression by regulating PRMT1 mediated STAT3 arginine methylation

Osteosarcoma (OS), the most common primary malignancy of the bone, has a poor prognosis due to its high mortality rate and high potential for metastasis. Thus, it is urgently necessary to explore functional molecular targets of therapeutic strategies for osteosarcoma. Here, we reported that TIPE1 expression was decreased in osteosarcoma tissues compared to normal and adjacent nontumor tissues, and its expression was negatively related to tumor stage and tumor size. Functional assays showed that TIPE1 inhibited osteosarcoma carcinogenesis and metastatic potential both in vivo and in vitro. Furthermore, we investigated that the STAT3 signaling pathway was significantly downregulated after TIPE1 overexpression. Mechanistically, TIPE1 bind to the catalytic domain of PRMT1, which deposits an asymmetric dimethylarginine (ADMA) mark on histone/non-histone proteins, and thus inhibited PRMT1 mediated STAT3 methylation at arginine (R) residue 688. This abolished modification decreased STAT3 transactivation and expression, by which subsequently suppressed osteosarcoma malignancy. Taken together, these data showed that TIPE1 inhibits the malignant transformation of osteosarcoma through PRMT1-mediated STAT3 arginine methylation and ultimately decreases the development and metastasis of osteosarcoma. TIPE1 might be a potential molecular therapeutic target and an early biomarker for osteosarcoma diagnosis.

In silico and in vivo analysis of TIPE1 expression in diffuse large B cell lymphoma

TIPE1 is a gene in the TNFAIP8 family involved in immune regulation and tumorigenesis. Although previous studies demonstrated that TIPE1 might play different roles in different tumors, its expression and role in lymphoma are unclear. Here we observed TIPE1 expression in diffuse large B cell lymphoma (DLBCL). Two microarrays containing 96 tumor tissue specimens were obtained from the Affiliated Hospital of Nantong University biobank. All specimens came from patients with a clear pathological diagnosis of lymphoma, lymphadenitis, breast cancer, or bladder cancer, and we performed immunohistochemical experiments on these tissue specimens. GEPIA and TIMER platforms were used for bioinformatic analyses. We found higher TIPE1 expression in tumor tissues from patients with lymphoma compared with those with lymphadenitis, breast cancer, or bladder cancer. The GEPIA and TIMER analyses revealed that TIPE1 was upregulated in DLBCL tissues but not in invasive breast carcinoma, urothelial bladder carcinoma, or liver hepatocellular carcinoma tissues. TIPE1 expression was irrelevant for pathological stage, overall survival, or DLBCL immune infiltration levels. However, TIPE1 expression was correlated with MKI67 expression in DLBCL. Overall, TIPE1’s high expression levels in DLBCL may contribute to tumor growth in DLBCL.

Molecular cloning, characterization, and expression analysis of TIPE1 in chicken (Gallus gallus): Its applications in fatty liver hemorrhagic syndrome

Tumor necrosis factor-α-induced protein eight like 1 (TIPE1) plays important role in autophagy, immunity, and lipid metabolism. The potential role of TIPE1 in fatty liver hemorrhage syndrome (FLHS) is elusory. In the present study, the full-length coding sequence of TIPE1 was cloned, and the polyclonal antibody of TIPE1 was produced by the recombinant TIPE1 protein. The bioinformatic analysis showed that the chicken TIPE1 protein, which was predicted to be a hydrophobic and non-transmembrane protein without signal peptide was highly different from that of mammals. Furthermore, proceeded by using TIPE1 polyclonal antibody, the tissue distribution analysis showed that TIPE1 protein is ubiquitously expressed in various tissues in adult hens and chicks, with its level being higher in the liver and, spleen, moderate in intestinal, brain, and heart. Besides, immunohistochemistry and immunofluorescence observation demonstrated that TIPE1 mainly existed in the cytoplasm in liver, duodenum, and cecum cell. Notably, the TIPE1 expressions were significantly decreased in laying hens suffering from FLHS. Collectively, these results showed that the chicken TIPE1 polyclonal antibody was successfully prepared and further used to analyze the expression profiles of chicken. And the expression of TIPE1 was reduced in FLHS which provided the foundation for further investigation in FLHS.

Phosphoinositide-binding protein TIPE1 promotes alternative activation of macrophages and tumor progression via PIP3/Akt/TGF-β axis

Macrophages perform key and distinct functions in maintaining tissue homeostasis by finely tuning their activation state. Within the tumor microenvironment, macrophages are reshaped to drive tumor progression. Here we report that tumor necrosis factor α-induced protein 8-like 1 (TIPE1) is highly expressed in macrophages, and that depletion of TIPE1 impedes alternative activation of macrophages. TIPE1 enhanced activation of the PI3K/Akt pathway in macrophages by directly binding with and regulating the metabolism of phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidylinositol 3,4,5-trisphosphate (PIP3). Accordingly, inhibition of the PI3K/Akt pathway significantly attenuated the effect of TIPE1 on macrophage alternative activation. Tumor-associated macrophages (TAM) in human liver cancer and melanoma tissues showed significantly upregulated TIPE1 expression that negatively correlated with patient survival. In vitro and in vivo, TIPE1 knockdown in macrophages retarded the growth and metastasis of liver cancer and melanoma. Furthermore, blockade or depletion of TGF-β signaling in macrophages abrogated the effects of TIPE1 on tumor cell growth and migration. Together, these results highlight that the phosphoinositide-related signaling pathway involves reprogramming tumor-associated macrophages to optimize the microenvironment for cancer progression.

Upregulation of TIPE1 in tubular epithelial cell aggravates diabetic nephropathy by disrupting PHB2 mediated mitophagy

Renal tubular epithelial cells (RTECs) are one of the most mitochondria-rich cell types, and are thus vulnerable to mitochondrial dysregulation, which is defined as a pivotal event in tubular damage in diabetic nephropathy (DN). However, the underlying mechanisms remain largely unknown. Here, we investigated the role and mechanisms of tumor necrosis factor alpha-induced protein 8-like 1 (TNFAIP8L1/TIPE1) in high glucose (HG)-induced mitochondrial dysfunction in RTECs and DN progression. TIPE1 expression was predominantly upregulated in RTECs in patients with DN and mice with streptozotocin (STZ)-induced DN. Conditional knockout of Tipe1 in RTECs significantly decreased the urine protein creatinine ratio, renal tubular damage, epithelial-mesenchymal transition, and interstitial fibrosis in STZ-induced mice. RNA sequencing revealed that citrate cycle-related genes were positively enriched in the renal tissues of RTEC-specific Tipe1 knockout mice. Tipe1 deficiency upregulated ATP levels, mitochondrial membrane potential, and respiration rate, but downregulated mitochondrial ROS levels in RTECs. Furthermore, Tipe1 ablation led to enhanced mitophagy in RTECs, indicative of increased LC3II, PINK1, and Parkin expression, but decreased p62 expression in mitochondria. Mechanistically, mass spectrometry screening and co-immunoprecipitation assays revealed the interaction of TIPE1 with prohibitin 2 (PHB2), a crucial mitophagy receptor. Intriguingly, TIPE1 promoted the ubiquitination and proteasomal degradation of PHB2. Subsequently, PHB2 knockdown almost abrogated the improvement of Tipe1 loss on HG-induced tubular cell mitophagy and damage. Thus, TIPE1 disrupts mitochondrial homeostasis in RTECs and promotes tubular damage by destabilizing PHB2 under HG conditions. Hence, TIPE1 may act as a potential therapeutic target to prevent DN progression.

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TIPE1 is highly expressed in RTECs of DN.

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TIPE1 aggravates diabetic renal injury and fibrosis.

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TIPE1 disrupts the mitochondria homeostasis of RTECs by inhibiting mitophagy.

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TIPE1 interacts with and promotes the proteasomal degradation of PHB2.

TNF-α-Induce Protein 8-Like 1 Inhibits Hepatic Steatosis, Inflammation, and Fibrosis by Suppressing Polyubiquitination of Apoptosis Signal-Regulating Kinase 1

BACKGROUND AND AIMS

Characterized by hepatocyte steatosis, inflammation, and fibrosis, NASH is a complicated process that contributes to end-stage liver disease and, eventually, HCC. TNF-α-induced protein 8-like 1 (TIPE1), a new member of the TNF-α-induced protein 8 family, has been explored in immunology and oncology research; but little is known about its role in metabolic diseases.

APPROACH AND RESULTS

Here, we show that hepatocyte-specific deletion of TIPE1 exacerbated diet-induced hepatic steatosis, inflammation, and fibrosis as well as systemic metabolic disorders during NASH pathogenesis. Conversely, hepatocyte-specific overexpression of TIPE1 dramatically prevented the progression of these abnormalities. Mechanically, TIPE1 directly interacted with apoptosis signal-regulating kinase 1 (ASK1) to suppress its TNF receptor-associated factor 6 (TRAF6)-catalyzed polyubiquitination activation upon metabolic challenge, thereby inhibiting the downstream c-Jun N-terminal kinase and p38 signaling pathway. Importantly, dramatically reduced TIPE1 expression was observed in the livers of patients with NAFLD, suggesting that TIPE1 might be a promising therapeutic target for NAFLD and related metabolic diseases.

CONCLUSIONS

TIPE1 protects against hepatic steatosis, inflammation, and fibrosis through directly binding ASK1 and restraining its TRAF6-catalyzed polyubiquitination during the development of NASH. Therefore, targeting TIPE1 could be a promising therapeutic approach for NAFLD treatment.

Understanding the regulation of β-catenin expression and activity in colorectal cancer carcinogenesis: beyond destruction complex

Aberrant Wnt/β-catenin signaling is central to colorectal cancer carcinogenesis. The well-known potential of targeting the canonical Wnt signaling pathway for the treatment of CRC is largely attributed to the ability of this pathway to regulate various cellular processes such as cell proliferation, metastasis, drug resistance, immune response, apoptosis, and cellular metabolism. However, with the current approach of targeting this pathway, none of the Wnt-targeted agents have been successfully implicated in clinical practice. Instead of using classical approaches to target this pathway, there is a growing need to find new and modified approaches to achieve the same. For this, a better understanding of the regulation of β-catenin, a major effector of the canonical Wnt pathway is a must. The present review addresses the importance of understanding the regulation of β-catenin beyond the destruction complex. Few recently discovered β-catenin regulators such as ZNF281, TTPAL, AGR2, ARHGAP25, TREM2, and TIPE1 showed significant potential in regulating the development of CRC through modulation of the Wnt/β-catenin signaling pathway in both in vitro and in vivo studies. Although the expression and activity of β-catenin is influenced by many protein regulators, the abovementioned proteins not only influence its expression and activation but are also directly involved in the development of CRC and various other solid tumors. Therefore, we hypothesise that focusing the current research on finding the detailed mechanism of action of these regulators may assist in providing with a better treatment approach or improve the current therapeutic regimens.

TIPE1 Suppresses Growth and Metastasis of Ovarian Cancer

TIPE1, a newly identified member in TIPE (TNFAIP8) family, plays an important role in tumorigenesis and immune regulation, but its role in ovarian cancer, especially in tumor metastasis, remains unknown. In the current study, we aimed to reveal the protein expression spectrum of TIPE1 in normal human tissues and explored its relationship with metastasis in ovarian cancer. The results of IHC staining showed that TIPE1 protein was not only detected in cytoplasm in most human tissues but also expressed in both cytoplasm and nucleus in squamous epithelium and some epithelial-derived cells with secretory functions, such as esophagus, cervix uteri and ovary, and thyroid gland. Moreover, TIPE1 protein was downregulated in ovarian cancer tissues compared with that in the paracancerous. More importantly, TIPE1 suppressed tumorigenesis and metastasis of ovarian cancer in vitro and in vivo, as evidence shows its ability to suppress growth, colony formation, migration, and epithelial-mesenchymal transition (EMT) of ovarian cancer. Taken together, our results demonstrate the suppressor role of TIPE1 in ovarian cancer metastasis, indicating TIPE1 might be a metastasis predictor and a novel therapeutic target for ovarian cancer.

TIPE1 Promotes Cervical Cancer Cell Chemoresistance to Cisplatin in a Wild-Type p53-Dependent Manner

Previous studies have revealed that TIPE1 serves as a tumor suppressor gene in several tumor types. However, we demonstrated that TIPE1 can promote cervical cancer proliferation by suppressing p53 activity. Here, we showed that TIPE1 inhibits cervical cancer cell apoptosis both in vivo and in vitro. Mechanistically, we revealed that TIPE1 facilitates chemoresistance in a wild-type p53-dependent manner. The results indicated that TIPE1 is responsible for the transition from chemosensitivity to chemoresistance, and that it can serve as a promising target in cervical cancer chemotherapy.

Microarray gene expression profiling provides insights into functions of TIPE2 in HBV-related apoptosis

Tumor necrosis factor-α-induced protein-8 like-2 (TNFAIP8L2, TIPE2), a member of TNFAIP8 family, functions as a regulator in inflammation. Our previous studies showed that TIPE2 can negatively regulate HBV-specific CD8⁺ T lymphocyte functions. But the effect of TIPE2 on the apoptosis of HBV-infected hepatocytes which is very important for eliminating viruses remains unclear. Using gene expression microarray analysis, we find that TIPE2 deficiency can regulate the expression of apoptotic genes in liver tissues from HBV hydrodynamic injection (HI) mouse model. TIPE2 protein was detected in TUNEL staining positive hepatocytes in HBV-infected C57 mice. Interestingly, the TIPE2 expressed hepatocytes were just the HBV infected cells. Furthermore, TIPE2 upregulates the mRNA levels of FasL, Bim and TNFRsF1b which promote cells death, when TIPE2 was transfected into HepG2 cells in vitro. As a result, TIPE2 overexpression cells showed a higher number of apoptotic cells and increased level of cleavage caspase3 compared to controls. Those results indicate that TIPE2 participates in HBV infection by regulating apoptosis of virus-infected hepatocytes.

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.

TIPE1 impairs ovarian tumor growth by promoting caspase-dependent apoptosis

Tumor necrosis factor-α-induced protein 8-like 1 (TIPE1) functions as a tumor suppressor in several types of cancer, including lung and breast cancer. The present study aimed to determine the level of expression and the function of TIPE1 in ovarian cancer. TIPE1 expression was determined in tissue microarrays and ovarian cancer cells, and these data were analyzed to assess the association between TIPE1 expression and prognosis in patients with ovarian cancer. The potential antitumor effects of TIPE1 were investigated in vitro and in a xenograft mouse model. Furthermore, the underlying molecular mechanism by which TIPE1 regulates ovarian cancer growth was determined via flow cytometric analysis, western blotting and rescue experiments. The results of the present study indicated that TIPE1 levels were markedly decreased in ovarian cancer tissues, and its level of expression was associated with a favorable prognosis of patients with ovarian cancer. In addition, ectopic TIPE1 expression significantly impaired A2780 and SKOV3 cell proliferation and colony formation in vitro, which was accompanied by efficient inhibition of xenograft tumor growth in mice. Investigations into the underlying molecular mechanism demonstrated that TIPE1 induced ovarian cancer cell apoptosis by promoting caspase protein expression. Inhibition of caspase-dependent apoptosis by z-VAD blocked TIPE1-mediated inhibition of the proliferation and induction of apoptosis in ovarian cancer cells. Collectively, the results of the present study suggest that TIPE1 may be a potential prognostic predictor and therapeutic target for patients with ovarian cancer.

TIPE1 impairs stemness maintenance in colorectal cancer through directly targeting β-catenin

TIPE1 (tumor necrosis factor-α-induced protein 8-like 1) contributes to cell death in diverse cancers. However, the expression and biological functions of TIPE1 in colon cancer remain unclear. In the present study, we report that TIPE1 was downregulated in colon cancer tissues and positively correlates with prognosis of colon cancer patients. TIPE1 overexpression significantly inhibits colon cancer cell growth both in vitro and in vivo through impairing stemness, accompanied with downregulation of the stemness-related markers, ALDH, CD133, CD44 and SOX-9. Mechanically, TIPE1 directly targets β-catenin and promotes β-catenin degradation in a protease-dependent manner, and Wnt/β-catenin signaling plays a crucial role during TIPE1-mediated stemness inhibition in colon cancer. These findings reveal that TIPE1 exerts anti-tumor effects in colon cancer and suggest that TIPE1 would be a therapeutic target for cancers.

TIPE1-mediated autophagy suppression promotes nasopharyngeal carcinoma cell proliferation via the AMPK/mTOR signalling pathway

Recent studies have shown that tumour necrosis factor‐α–induced protein 8 like‐1(TIPE1) plays distinct roles in different cancers. TIPE1 inhibits tumour proliferation and metastasis in a variety of tumours but acts as an oncogene in cervical cancer. The role of TIPE1 in nasopharyngeal carcinoma (NPC) remains unknown. Interestingly, TIPE1 expression was remarkably increased in NPC tissue samples compared to adjacent normal nasopharyngeal epithelial tissue samples in our study. TIPE1 expression was positively correlated with that of the proliferation marker Ki67 and negatively correlated with patient lifespan. In vitro, TIPE1 inhibited autophagy and induced cell proliferation in TIPE1‐overexpressing CNE‐1 and CNE‐2Z cells. In addition, knocking down TIPE1 expression promoted autophagy and decreased proliferation, whereas overexpressing TIPE1 increased the levels of pmTOR, pS6 and P62 and decreased the level of pAMPK and the LC3B. Furthermore, the decrease in autophagy was remarkably rescued in TIPE1‐overexpressing CNE‐1 and CNE‐2Z cells treated with the AMPK activator AICAR. In addition, TIPE1 promoted tumour growth in BALB/c nude mice. Taken together, results indicate that TIPE1 promotes NPC progression by inhibiting autophagy and inducing cell proliferation via the AMPK/mTOR signalling pathway. Thus, TIPE1 could potentially be used as a valuable diagnostic and prognostic biomarker for NPC.

Effect of TIPE1 on Immune Function of Dendritic Cells and Its Signaling Pathway in Septic Mice

Dendritic cell (DC) dysfunction plays a pivotal role in sepsis-induced immunosuppression. Tumor necrosis factor α (TNF-α)-induced protein 8 like-1 (TIPE1), a new member of the tumor necrosis factor α-induced protein 8 family, may be related to cell death. The aim of the present study was to elucidate the effect of TIPE1 on the immune function of DCs and its regulatory mechanism via PD-L1/PD-1 signaling in mice. Sepsis was induced in adult C57BL/6 male mice via cecal ligation and puncture. In vitro, we found that expression of CD80, CD86, and major histocompatibility complex class II in DCs and levels of cytokines, including tumor necrosis factor α and interleukin 12p40, were elevated; similarly, T-cell proliferation and differentiation were promoted when the gene expressing TIPE1 was silenced. Next, we examined the in vivo role of TIPE1 in a cecal ligation and puncture animal model system. Flow cytometry of the immune functional status in DCs revealed negative regulation of TIPE1 on DC maturation, as well as activation. Moreover, changes in PD-L1/PD-1 levels confirmed the negative effect of TIPE1 in DCs. Collectively, we report that TIPE1 might exert negative regulation in sepsis, at least in part by inhibiting DC maturation and subsequent T-cell-mediated immunity via PD-L1/PD-1 signaling.

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.

TIPE1 accelerates atherogenesis by inducing endothelial dysfunction in response to oxidative stress

Atherosclerosis is an inflammatory disease of the arterial wall, which involves endothelial cells and immune cells. Endothelial dysfunction has been considered an important step in the initiation of the disease. TIPE1 is a newly identified protein of the TIPE family, and plays a vital role in inflammation and tumorigenesis. However, its role in atherogenesis remains unclear. In this study, we demonstrated that TIPE1 promoted atherogenesis by inducing endothelial dysfunction. When human umbilical vein endothelial cells (HUVECs) were exposed to oxidative stress, the level of TIPE1 was significantly up-regulated, and the ROS generation markedly increased in TIPE1 over-expressing HUVECs. As a result, the growth of HUVECs was inhibited, and the apoptosis was enhanced. However, the cell contact ability between HUVECs and THP-1 cells were augmented due to the up-regulation of adhesion molecules such as E-selectin and ICAM-1 induced by TIPE1 overexpression. Importantly, ApoE^-/- mice injected with TIPE1 recombinant lentivirus developed significantly severe atherosclerosis accompanied by hyperglycemia, hypercholesterolemia and increased white blood count. These findings indicated that excessive ROS induced by the overexpression of TIPE1 in endothelial cells accelerated the process of atherogenesis.

TNFAIP8L1 and FLT1 polymorphisms alter the susceptibility to cervical cancer amongst uyghur females in China

TNFAIP8L1 and FLT1 play critical roles in the occurrence and development of tumors, but no in-depth studies have been carried out in cervical cancer. The present study aims to research the correlation between polymorphisms of these two genes and the risk of cervical cancer in the Uygur women. The study involved 342 cervical cancer patients and 498 healthy women. Five single nucleotide polymorphisms (SNPs) from the TNFAIP8L1 gene and the FLT1 gene were selected and genotyped. Odds ratio and 95% CIs were calculated by logistic regression analysis to evaluate the correlation between SNPs and cervical cancer risk. The alleles rs9917028-A (P=0.032), rs10426502-A (P=0.007), and rs1060555-G (P=0.026) of TNFAIP8L1 were associated with a decreased risk of cervical cancer. In the multiple genetic models, these three SNPs were also associated with the risk of cervical cancer. The stratified analysis showed that TNFAIP8L1-rs10426502, -rs1060555, and FLT1-rs9513111 were associated with a decreased risk of cervical cancer amongst people older than 43 years. Moreover, the haplotypes AG (P=0.007) and GC (P=0.026) of linkage disequilibrium block rs10426502|rs1060555 in TNFAIP8L1 were significantly associated with an increased risk of cervical cancer. Our results suggested that the relationships between TNFAIP8L1 and FLT1 polymorphisms and the risk of cervical cancer amongst Uyghur females.

TIPE1 Inhibits Breast Cancer Proliferation by Downregulating ERK Phosphorylation and Predicts a Favorable Prognosis

TIPE1, which acts as a cell death regulator, has emerged as a tumor suppressor in the process of carcinogenesis. However, our recent research demonstrated that it serves as an oncogene in the pathogenesis of cervical cancer, indicating that the role of TIPE1 in carcinogenesis needs to be further evaluated. In this study, we show that TIPE1 is able to inhibit breast cancer cell growth both in vivo and in vitro. Functionally, TIPE1 inhibits cancer cell proliferation preferentially by downregulating ERK phosphorylation. Furthermore, the expression of TIPE1 is decreased in breast cancer tissues compared to matched adjacent tissues, and its expression is positively correlated with patients' lifespan. These data indicate that TIPE1 suppresses breast cancer proliferation by inhibiting the ERK signaling pathway. This study also suggests that TIPE1 could serve as a potential therapeutic target and a diagnostic biomarker for breast cancer.

Oncogenic Role of Tumor Necrosis Factor α-Induced Protein 8 (TNFAIP8)

Tumor necrosis factor (TNF)-α-induced protein 8 (TNFAIP8) is a founding member of the TIPE family, which also includes TNFAIP8-like 1 (TIPE1), TNFAIP8-like 2 (TIPE2), and TNFAIP8-like 3 (TIPE3) proteins. Expression of TNFAIP8 is strongly associated with the development of various cancers including cancer of the prostate, liver, lung, breast, colon, esophagus, ovary, cervix, pancreas, and others. In human cancers, TNFAIP8 promotes cell proliferation, invasion, metastasis, drug resistance, autophagy, and tumorigenesis by inhibition of cell apoptosis. In order to better understand the molecular aspects, biological functions, and potential roles of TNFAIP8 in carcinogenesis, in this review, we focused on the expression, regulation, structural aspects, modifications/interactions, and oncogenic role of TNFAIP8 proteins in human cancers.

Comparative gene expression analysis after exposure to 123I-iododeoxyuridine, γ- and α-radiation-potential biomarkers for the discrimination of radiation qualities

Gene expression analysis was carried out in Jurkat cells in order to identify candidate genes showing significant gene expression alterations allowing robust discrimination of the Auger emitter 123I, incorporated into the DNA as 123I-iododeoxyuridine (123IUdR), from α- and γ-radiation. The γ-H2AX foci assay was used to determine equi-effect doses or activity, and gene expression analysis was carried out at similar levels of foci induction. Comparative gene expression analysis was performed employing whole human genome DNA microarrays. Candidate genes had to show significant expression changes and no altered gene regulation or opposite regulation after exposure to the radiation quality to be compared. The gene expression of all candidate genes was validated by quantitative real-time PCR. The functional categorization of significantly deregulated genes revealed that chromatin organization and apoptosis were generally affected. After exposure to 123IUdR, α-particles and γ-rays, at equi-effect doses/activity, 155, 316 and 982 genes were exclusively regulated, respectively. Applying the stringent requirements for candidate genes, four (PPP1R14C, TNFAIP8L1, DNAJC1 and PRTFDC1), one (KLF10) and one (TNFAIP8L1) gene(s) were identified, respectively allowing reliable discrimination between γ- and 123IUdR exposure, γ- and α-radiation, and α- and 123IUdR exposure, respectively. The Auger emitter 123I induced specific gene expression patterns in Jurkat cells when compared with γ- and α-irradiation, suggesting a unique cellular response after 123IUdR exposure. Gene expression analysis might be an effective tool for identifying biomarkers for discriminating different radiation qualities and, furthermore, might help to explain the varying biological effectiveness at the mechanistic level.

Tumor Necrosis Factor-α Induced Protein 8: Pathophysiology, Clinical Significance, and Regulatory Mechanism

Tumor necrosis factor-α-induced protein-8 (TNFAIP8) is the earliest discovered component of TNFAIP8 family [tumor necrosis factor-α-induced protein-8 like (TIPE) family]. TNFAIP8 contains a putative death effector domain (DED) homologous to DED II in FLIP (Fas-associated death domain-like interleukin-1β-converting enzyme-inhibitory protein), which may affect cell survival/death process. Recently, it has been demonstrated that TNFAIP8 could inhibit apoptosis and autophagy in various types of cells. Moreover, TNFAIP8 level fluctuated evidently in patients with inflammatory, malignant, and autoimmune diseases, indicating that it might be an anti-apoptotic and oncogenetic protein. Herein we will review the discovery, gene/protein structure, pathophysiological functions, and clinical significance of TNFAIP8 together with its potential regulatory mechanism.

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.

Gene delivery of TIPE2 inhibits breast cancer development and metastasis via CD8+ T and NK cell-mediated antitumor responses

Breast cancer is the second leading cause of cancer-related deaths in the female patients which was mainly caused by metastasis. Development of target gene therapy for breast cancer to suppress tumor progress and metastasis will improve the therapeutic options and be of great benefit to the patients. Tumor necrosis factor-alpha-induced protein 8-like 2 is a novel molecule for maintaining immune homeostasis and is involved in cancer development. In the present study, we overexpressed TIPE2 in breast cancer cells to investigate the role of TIPE2 in the development of breast cancer. Our results showed that overexpression of TIPE2 significantly inhibited the proliferation of 4T1 cells in vitro and in vivo. We constructed a non-viral targeted gene therapeutic system by using the minicircle plasmids expressing TIPE2. We found that the growth and metastasis of breast cancer was significantly inhibited by hydrodynamic gene delivery of TIPE2 plasmids in vivo. Mechanistically, TIPE2 increased T and NK cells, and decreased MDSCs. Gene delivery of TIPE2 up-regulated the production of IFN-γ and TNF-α by CD8⁺ T and NK cells in spleens and tumor microenvironment, and enhanced the cytotoxic activity of CD8⁺ T and NK cells. Taken together, TIPE2 inhibited breast cancer development and metastasis possibly via promoting CD8⁺ T and NK cell-mediated antitumor immune responses. Thus, the results indicate that TIPE2 may be a potential therapeutic target for breast cancer therapy.

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.

Tumor necrosis factor α-induced protein 8-like 1 promotes apoptosis by regulating B-cell leukemia/lymphoma-2 family proteins in RAW264.7 cells

Although the newly identified protein tumor necrosis factor α-induced protein 8-like 1 (TNFAIP8L1), also known as TIPE1, has been reported to be able to induce apoptosis in human hepatocellular carcinoma cells, the involvement of TIPE1 in apoptosis remains to be elucidated. The present study investigated the pro-apoptotic effect of TIPE1 in an murine macrophage cell line, RAW264.7. The cell apoptosis rate was detected by flow cytometry. The results revealed that overexpressed TIPE1 could directly enhance the apoptosis and the cisplatin-induced cell death of RAW264.7 cells in vitro. Meanwhile, TIPE1 overexpression could suppress tumor growth in vivo. Furthermore, western blotting revealed that overexpressed TIPE1 could upregulate the expression of B-cell leukemia/lymphoma (Bcl)-2 associated X protein (Bax), Bcl-2 interacting killer (Bik) and p53 upregulated modulator of apoptosis (Puma), and activate the mitogen activated protein kinases (MAPKs) signaling pathway. However, western blotting demonstrated that inhibitors of the MAPKs pathway could not decrease the expression of Bax, Bik or Puma. These results indicated that TIPE1 could promote the apoptosis of RAW264.7 cells by upregulating the pro-apoptotic members of the Bcl-2 family of proteins, and that the MAPKs signaling pathway was not involved in the pro-apoptotic effect of TIPE1.

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.

TIPE2 Inhibits Lung Cancer Growth Attributing to Promotion of Apoptosis by Regulating Some Apoptotic Molecules Expression

Recent studies found that TIPE2 was involved in cancer development. However, little is known about TIPE2 in lung cancer. Our study aims to clarify the role of TIPE2 in lung carcinogenesis. We examined the expression of TIPE2 in lung squamous cancer (LSC), small cell lung cancer and lung adenocarcinoma (AdC) tissues and found that TIPE2 expression was lost in small cell lung cancer, compared with adjacent non-tumor tissues. Overexpression of TIPE2 significantly inhibited the growth of lung cancer cell H446 in vitro and even suppressed tumor formation in vivo. Flow cytometry analysis found TIPE2 overexpression promoted apoptosis of H446. In TIPE2 over-expression cells, caspase-3, caspase-9, and Bax were significantly up-regulated while Bcl-2 was down-regulated. Moreover, coincident results were shown by immunohistochemistry in tumors from nude mice. TIPE2 inhibited the phosphorylation of Akt, while promoting the phosphorylation of P38, but had no effect on IκBα and ERK pathway. Taken together, TIPE2 promoted lung cancer cell apoptosis through affecting apoptosis-related molecules caspase-3, caspase-9, Bcl-2 and Bax, possibly via regulating P38 and Akt pathways, indicating that TIPE2 might be a novel marker for lung cancer diagnosis and therapy.

Identical expression profiling of human and murine TIPE3 protein reveals links to its functions

Tumor necrosis factor-alpha-induced protein-8 like-3 (TNFAIP8L3, TIPE3) is a newly discovered member of TNFAIP8 family and regarded as a lipid second messenger transfer protein that promotes cancer. Yet the nature of the cells and tissues that express TIPE3 protein has not been determined. In this study, we examined TIPE3 expression in various murine and human tissues by immunohistochemistry and quantitative PCR. We found that TIPE3 expression was almost identical in most organs from human and mice. TIPE3 is a cytoplasmic protein expressed preferentially in epithelial-derived cells with secretory functions. Furthermore, TIPE3 protein is highly expressed in most human carcinoma cell lines. These results suggest that TIPE3 may play important roles in carcinogenesis and cell secretion.

TIPE1 induces apoptosis by negatively regulating Rac1 activation in hepatocellular carcinoma cells

TIPE1 (tumor necrosis factor-α-induced protein 8-like 1 or TNFAIP8L1) is a newly identified member of the TIPE (TNFAIP8) family, which play roles in regulating cell death. However, the biologic functions of TIPE1 in physiologic and pathologic conditions are largely unknown. Here, we report the roles of TIPE1 in hepatocellular carcinoma (HCC). Evaluated by immunohistochemical staining, HCC tissues showed significantly downregulated TIPE1 expression compared with adjacent non-tumor tissues, which positively correlated with tumor pathologic grades and patient survival. Using a homograft tumor model in Balb/c mice, we discovered that TIPE1 significantly diminished the growth and tumor weight of murine liver cancer homografts. Consistently, TIPE1 inhibited both cell growth and colony formation ability of cultured HCC cell lines, which was further identified to be due to TIPE1-inducing apoptosis in a caspase-independent, necrostatin-1 (Nec-1)-insensitive manner. Furthermore, mechanistic investigations revealed that TIPE1 interacted with Rac1, and inhibited the activation of Rac1 and its downstream p65 and c-Jun N-terminal kinase pathway. Moreover, overexpression of constitutively active Rac1 partially rescued the apoptosis induced by TIPE1, and Rac1 knockdown significantly restored the deregulated cell growth induced by TIPE1 small interfering RNA. Our findings revealed that TIPE1 induced apoptosis in HCC cells by negatively regulating Rac1 pathway, and loss of TIPE1 might be a new prognostic indicator for HCC patients.

Human tumor necrosis factor (TNF)-alpha-induced protein 8-like 2 suppresses hepatocellular carcinoma metastasis through inhibiting Rac1

Background

Tumor invasion and metastasis are the major reasons for leading death of patients with hepatocellular carcinoma (HCC). Therefore, to identify molecules that can suppress invasion and metastasis of tumor will provide novel targets for HCC therapies. Tumor necrosis factor (TNF)-alpha-induced protein 8-like 2, TIPE2, is a novel immune negative molecule and an inhibitor of the oncogenic Ras in mice but its function in human is unclear. Our previous research has shown that TIPE2 is downregulated in human primary HCC compared with the paired adjacent non-tumor tissues.

Results

In present study, we provide evidence that TIPE2 inhibits effectively human hepatocellular carcinoma metastasis. The forced expression of TIPE2 in HCC-derived cell lines markedly inhibits tumor cell growth, migration and invasion in vitro and suppresses growth and metastasis of HCC in vivo. Clinical information from a cohort of 112 patients reveals that loss or reduced expression of TIPE2 in primary HCC tissues is significantly associated with tumor metastasis. Mechanically, TIPE2 inhibits the migration and invasion through targeting Rac1 and then reduces F-actin polymerization and expression of matrix metallopeptidase 9 (MMP9) and urokinase plasminogen activator (uPA).

Conclusion

Our results indicate that human TIPE2 is endogenous inhibitor of Rac1 in HCC by which it attenuates invasion and metastasis of HCC. The data suggest that TIPE2 will be a new target for HCC therapy.

Functional variants in TNFAIP8 associated with cervical cancer susceptibility and clinical outcomes

Tumor necrosis factor-α-induced protein 8 (TNFAIP8) is an anti apoptotic and pro-oncogenic signaling molecule involved in the process of immunity, carcinogenesis and tumor progression. Single nucleotide polymorphisms (SNPs) at microRNA-binding sites may change messenger RNA target gene function, thus leading to cancer susceptibility and tumor progression. In this study of 1584 cervical cancer cases and 1394 cancer-free female controls, we investigated associations between three potentially functional SNPs in TNFAIP8 family genes and cervical cancer risk as well as platinum resistance and clinical outcomes in Eastern Chinese women. We found that the TNFAIP8-rs11064 variant GG genotype was associated with an increased risk of cervical cancer compared with AA/AG genotypes (adjusted odds ratio = 2.16, 95% confidence interval = 1.16-4.03, P = 0.015). Further in vitro and ex vivo functional experiments demonstrated that the TNFAIP8-rs11064 variant G allele weakened the binding affinity of miR-22 to the TNFAIP8 3'-untranslated region (UTR) in four cancer cell lines, resulting in increased production of the TNFAIP8 protein in the patients' cervical tissues. In the survival subset, the high TNFAIP8 protein expression was significantly associated with both resistance to cisplatin and nedaplatin, recurrence and death from cervical cancer. Taken together, in the absence of information on human papillomavirus (HPV) infection, the TNFAIP8-rs11064 SNP may function by affecting the affinity of miR-22 binding to the 3'-UTR of TNFAIP8 and regulating TNFAIP8 expression, thus contributing to cervical cancer risk. Additionally, the increased TNFAIP8 protein expression may predict platinum resistance and clinical outcomes in cervical cancer patients. Larger, prospective studies with detailed HPV infection data are warranted to validate our findings.