Small-Molecule Inhibitors of TIPE3 Protein Identified through Deep Learning Suppress Cancer Cell Growth In Vitro.

Tumor necrosis factor-α-induced protein 8-like 3 (TNFAIP8L3 or TIPE3) functions as a transfer protein for lipid second messengers. TIPE3 is highly upregulated in several human cancers and has been established to significantly promote tumor cell proliferation, migration, and invasion and inhibit the apoptosis of cancer cells. Thus, inhibiting the function of TIPE3 is expected to be an effective strategy against cancer. The advancement of artificial intelligence (AI)-driven drug development has recently invigorated research in anti-cancer drug development. In this work, we incorporated DFCNN, Autodock Vina docking, DeepBindBC, MD, and metadynamics to efficiently identify inhibitors of TIPE3 from a ZINC compound dataset. Six potential candidates were selected for further experimental study to validate their anti-tumor activity. Among these, three small-molecule compounds (K784-8160, E745-0011, and 7238-1516) showed significant anti-tumor activity in vitro, leading to reduced tumor cell viability, proliferation, and migration and enhanced apoptotic tumor cell death. Notably, E745-0011 and 7238-1516 exhibited selective cytotoxicity toward tumor cells with high TIPE3 expression while having little or no effect on normal human cells or tumor cells with low TIPE3 expression. A molecular docking analysis further supported their interactions with TIPE3, highlighting hydrophobic interactions and their shared interaction residues and offering insights for designing more effective inhibitors. Taken together, this work demonstrates the feasibility of incorporating deep learning and MD simulations in virtual drug screening and provides inhibitors with significant potential for anti-cancer drug development against TIPE3-.

Down-regulated expression of TIPE3 inhibits malignant progression of non-small cell lung cancer via Wnt signaling.

Non-small cell lung cancer (NSCLC) accounts for approximately 80 % of all lung cancers with a low five-year survival rate. Therefore, the mechanistic pathways and biomarkers of NSCLC must be explored to elucidate its pathogenesis. In this study, we examined TIPE3 expression in NSCLC cells and investigated the molecular mechanisms underlying NSCLC regulation in vivo and in vitro. We collected tissue samples from patients with NSCLC to examine TIPE3 expression and its association with patient metastasis and prognosis. Furthermore, we evaluated the expression level of TIPE3 in NSCLC cells. Cell lines with the highest expression were selected for molecular mechanism experiments, and animal models were established for in vivo verification. The results showed that TIPE3 was significantly increased in patients with NSCLC, and this increased expression was associated with tumor metastasis and patient prognosis. TIPE3 knockdown inhibited proliferation, migration, invasion, EMT, angiogenesis, and tumorsphere formation in NSCLC cells. Moreover, it reduced the metabolic levels of tumor cells. However, overexpression of TIPE3 has the opposite effect. The in vivo results showed that TIPE3 knockdown reduced tumor volume, weight, and metastasis. Furthermore, the results showed that TIPE3 may inhibit malignant progression of NSCLC via the regulation of Wnt/ß-catenin expression. These findings suggest that TIPE3 is significantly elevated in patients with NSCLC and that downregulation of TIPE3 can suppress the malignant progression of NSCLC, which could serve as a potential diagnostic and treatment strategy for NSCLC.

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.

TIPE3 protects mice from lipopolysaccharide-induced acute lung injury.

BACKGROUND: Acute lung injury (ALI) is a severe inflammatory disease with high morbidity and mortality in patients and lung transplant recipients. Tumor necrosis factor-α-induced protein 8-like 3 (TIPE3) is one of the members of the TIPE family. While TIPE2 has been demonstrated to be protective against lipopolysaccharide (LPS)-induced ALI, the role of TIPE3 in ALI is currently unidentified. METHODS: To examine the role of TIPE3 in ALI, we pretreated C57BL/6 mice with control or TIPE3-lentivirus in LPS-induced ALI models. The C57BL/6 mice were randomly divided into four groups: control group; ALI-induced group; ALI-induced group with control lentivirus; and ALI-induced group with TIPE3-lentivirus. Additionally, RAW 264.7 cells were used to validate the role and molecular mechanism of TIPE3 signaling in vitro. RESULTS: An increased expression of TIPE3 reduced lung histopathological damage in ALI-affected mice. ALI-affected mice treated with TIPE3-lentivirus exhibited reduced lung microvascular permeability, myeloperoxidase (MPO) activity, neutrophil buildup, and inflammation response. Additionally, over-expression of TIPE3 significantly inhibited NF-κB activation and promoted the activation of Liver X receptors alpha (LXRα). In LPS-treated RAW264.7 cells, enforced TIPE3 expression produced anti-inflammatory effects, whereas the LXR inhibitor geranylgeranyl pyrophosphate (GGPP) reversed these effects. CONCLUSIONS: TIPE3 protected against LPS-induced ALI by regulating the LXRα/NF-κB signaling pathway. These results suggest that TIPE3 might provide a novel insight into the prevention of ALI.

Loss of TIPE3 reduced the proliferation, survival and migration of lung cancer cells through inactivation of Akt/mTOR, NF-κB, and STAT-3 signaling cascades.

Lung cancer is the foremost cause of cancer related mortality among men and one of the most fatal cancers among women. Notably, the 5-year survival rate of lung cancer is very low; 5% in developing countries. This low survival rate can be attributed to factors like late stage diagnosis, rapid postoperative recurrences in the patients undergoing treatment and development of chemoresistance against different agents used for treating lung cancer. Therefore, in this study we evaluated the potential of a recently identified protein namely TIPE3 which is known as a transfer protein of lipid second messengers as a lung cancer biomarker. TIPE3 was found to be significantly upregulated in lung cancer tissues indicating its role in the positive regulation of lung cancer. Supporting this finding, knockout of TIPE3 was also found to reduce the proliferation, survival and migration of lung cancer cells and arrested the G2 phase of cell cycle through inactivation of Akt/mTOR, NF-κB, STAT-3 signaling. It is well evinced that tobacco is the major risk factor of lung cancer which affects both males and females. Therefore, this study also evaluated the involvement of TIPE3 in tobacco mediated lung carcinogenesis. Notably, this study shows for the first time that TIPE3 positively regulates tobacco induced proliferation, survival and migration of lung cancer through modulation of Akt/mTOR signaling. Thus, TIPE3 plays critical role in the pathogenesis of lung cancer and hence it can be specifically targeted to develop novel therapeutic strategies.

TIPE3 promotes non-small cell lung cancer progression via the protein kinase B/extracellular signal-regulated kinase 1/2-glycogen synthase kinase 3ß-ß-catenin/Snail axis.

BACKGROUND: Tumor necrosis factor-α-induced protein 8-like 3 (TNFAIP8L3, also called TIPE3) has been shown to activate PI3K-AKT and MEK-ERK pathways. However, the roles of TIPE3 in progression of lung cancer are largely unknown. METHODS: Immunohistochemistry and western blotting were carried out to analyze the expression of TIPE3 in lung cancer clinical tissues and cells. TIPE3-overexpressing and knock-down NSCLC cell lines were established by transfer of TIPE3 coding sequence and shRNA, respectively. In vitro functional assays were performed to assess the effects of TIPE3 on proliferation and metastasis of NSCLC cells. Tumor xenograft mouse model was used to examine the roles of TIPE3 in growth of NSCLC cells in vivo. Western blotting, immunofluorescence, and immunohistochemistry were conducted to evaluate the association of TIPE3 and molecules related to AKT/ERK1/2-GSK3ß-ß-catenin/Snail pathway. PI3K, MEK, or GSK3ß kinase and proteasome inhibition assays as well as ß-Trcp and STUB1 siRNA assays were employed to determine the contribution of AKT/ERK1/2-GSK3ß signaling and ubiquitin-proteasome pathway to the regulatory effects of TIPE3 on expression of ß-catenin, Snail1, and Slug. RESULTS: We demonstrated that TIPE3 was elevated in lung cancer tissues and cells. The expression level of TIPE3 was positively correlated with malignant clinicopathological characteristics of lung cancer patients, such as tumor size, pathologic stage, and lymph node metastasis. Knockdown of TIPE3 suppressed the proliferation and growth of NSCLC cells as well as their migration and invasion ability, whereas TIPE3 overexpression facilitated these biological processes. Mechanistic data showed that TIPE3 promoted AKT and ERK1/2 signaling, inactivated GSK3ß activity, and enhanced the expression and transcriptional activity of ß-catenin, Snail1, and Slug in NSCLC cells. Kinase or proteasome inhibition and ß-Trcp or STUB1 knockdown assays further revealed that TIPE3 upregulated ß-catenin, Snail1, and Slug via the AKT/ERK1/2-GSK3ß pathway, in an ubiquitin-proteasome-dependent manner. More importantly, clinical data demonstrated that the expression level of TIPE3 was positively associated with the activation of AKT/ERK1/2-GSK3ß-ß-catenin/Snail pathway in lung cancer. CONCLUSIONS: Our findings indicate that upregulation of TIPE3 promotes the progression of human NSCLC considerably by activating ß-catenin, Snail1, and Slug transcriptional signaling via the AKT/ERK1/2-GSK3ß axis. Therefore, TIPE3 may represent a potential therapeutic target for NSCLC.

Effects of the long and short isoforms of TIPE3 on the growth and metastasis of gastric cancer.

Tumor necrosis factor alpha-induced protein 8-like 3 (TIPE3, also known as TNFAIP8L3) plays a vital role in tumorigenesis and development. However, it is unclear whether the two transcript variants of TIPE3 (long TIPE3 and short TIPE3) have an effect on the proliferation and metastasis of gastric cancer (GC). In this study, we demonstrated that the expression of TIPE3 decreased in GC, but patient prognosis worsened as TIPE3 expression increased. Then, overexpression models were constructed to study the role of long TIPE3 and short TIPE3. Upregulation of long TIPE3 and short TIPE3 promoted GC cell proliferation and metastasis both in vitro and in vivo, and the effect of short TIPE3 was more obvious. Further studies demonstrated that long TIPE3 and short TIPE3 promoted proliferation and metastasis of GC cells vis PI3K/Akt pathway. In conclusion, the two TIPE3 isoforms play an important role in the tumorigenesis of GC and depend on the activation of the PI3K/Akt pathway.

TIPE3 is a regulator of cell apoptosis in glioblastoma.

Tumor necrosis factor alpha-induced protein 8-like 3 (TIPE3) is closely related to tumourigenesis and development. However, its role in human glioblastoma (GBM) and the underlying mechanisms remain unclear. In this study, we demonstrate that TIPE3 is upregulated in GBM, and its high expression predicts poor prognosis. TIPE3 depletion induces GBM cell apoptosis both in vitro and in vivo. Mechanism studies reveal that TIPE3 inhibits p38 phosphorylation and negatively regulates the p38 MAPK pathway. TIPE3 associates with p38. The nuclear translocation of p38 is blocked by TIPE3 overexpression. And p38 phosphorylation could regulate TIPE3-mediated p38 nuclear-cytopalsmic translocation but does not affect TIPE3-p38 association. Rescue experiments confirm that TIPE3 inhibits GBM cell apoptosis via the p38 MAPK pathway. In conclusion, TIPE3 inhibits p38 phosphorylation and blocks p38 nuclear translocation. This action thus negatively regulates the p38 MAPK pathway and results in GBM cell survival.

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.

TIPE3 hypermethylation correlates with worse prognosis and promotes tumor progression in nasopharyngeal carcinoma.

BACKGROUND: Increasing evidence recognizes that DNA methylation abnormalities play critical roles in cancer development. Our previous genome-wide methylation profile showed that tumor necrosis factor-alpha-induced protein 8 like 3 (TIPE3) was hypermethylated in nasopharyngeal carcinoma (NPC). However, the relationship between TIPE3 methylation and its mRNA expression, as well as its biological roles in NPC are unknown. METHODS: Bisulfite pyrosequencing and quantitative RT-PCR were performed to quantify the TIPE3 methylation and expression levels. Kaplan-Meier curves and Cox regression analysis were used to estimate the correlation between TIPE3 methylation levels and survival in two patient cohorts collected from two hospitals (n = 441). The MTT, colony formation, Transwell migration and invasion assays, and xenograft tumor growth and lung metastatic colonization models were used to identify the functions of TIPE3 on NPC cells. RESULTS: We found that TIPE3 CpG island (CGI) was hypermethylated and its mRNA levels were downregulated in many cancers, including NPC. TIPE3 downregulation was associated with its CGI hypermethylation. Furthermore, NPC patients with high TIPE3 CGI methylation levels had poorer clinical outcomes than those with low methylation levels. The TIPE3 CGI methylation level was an independent prognostic factor. Moreover, restoring TIPE3 expression significantly inhibited NPC cell proliferation, migration and invasion in vitro, and suppressed tumor growth and lung metastatic colonization in vivo, while silencing TIPE3 acted in an opposite way. CONCLUSIONS: TIPE3 downregulation correlates with its CGI hypermethylation in several solid cancers. TIPE3 acts as a tumor suppressor in NPC, providing a further insight into NPC progression and representing a potential prognostic biomarker for NPC.

TIPE3 differentially modulates proliferation and migration of human non-small-cell lung cancer cells via distinct subcellular location.

BACKGROUND: TIPE3 (TNFAIP8L3), a transfer protein for lipid second messengers, is upregulated in human lung cancer tissues. The most popular lung cancer is non-small cell lung cancer (NSCLC) with high incidences and low survival rates, while the roles of TIPE3 in NSCLC remain largely unknown. METHODS: TIPE3 expression was examined in tissue chips from patients with NSCLC using immunohistochemistry; the correlation of plasma membrane expression of TIPE3 with T stage of NSCLC was analyzed. After endogenous TIPE3 was silenced via siRNA, or TIPE3 with N or C-terminal flag was overexpressed via transient or stable transfection, human NSCLC cells were assayed for the proliferation and migration, respectively. NSCLC cells, in which TIPE3 with C-terminal flag was stably transfected, were inoculated into mice to establish xenograft tumors, the tumor growth and the expression of TIPE3 in tumor tissues were examined. RESULTS: TIPE3 was broadly expressed in lung tissues of patients with NSCLC. The plasma membrane expression of TIPE3 was positively correlated with the T stage of NSCLC. Knockdown of endogenous TIPE3, which was predominantly expressed in the plasma membrane, inhibited the proliferation and migration of NSCLC cells. While transient overexpression of TIPE3 with N-terminal flag, which was mostly trapped in the cytoplasm, inhibited the growth and migration of NSCLC cells accompanied by inactivation of AKT and ERK. In contrast, stable overexpression of TIPE3 with C-terminal flag, which could be localized in the plasma membrane, markedly promoted the growth and migration of NSCLC cells through activation of AKT and ERK. Notably, in xenograft tumor models established with NSCLC cells, stable overexpression of TIPE3 with C-terminal flag in NSCLC cells significantly promoted the tumor growth and enhanced the expression and plasma membrane localization of TIPE3 in tumor tissues. CONCLUSION: This study demonstrates that human TIPE3 promotes the proliferation and migration of NSCLC cells depending on its localization on plasma membrane, whereas cytoplasmic TIPE3 may exert a negative function. Thus, manipulating the subcellular location of TIPE3 can be a promising strategy for NSCLC therapy.

Expression and its clinical significance of tumor necrosis factor-α-induced protein-8 like-3 in colonic mucosa of patients with colon cancer / 中华消化杂志

Objective To detect the expression of tumor necrosis factor-α-induced protein-8 like-3 (TIPE3) in colonic mucosa of patients with colon cancer,and to analyze the correlation between its abnormal expression and clinicopathological features of patients with colon cancer.Methods The expression of TIPE3 mRNA in 58 cases of colon cancer and tumor adjacent tissues was detected by realtime polymerase chain reaction (RT-PCR).The expression of TIPE3 at protein level in 83 cases of colon cancer and tumor-adjacent tissues was determined by SP immunohistochemistry.Nonparametric rank-sum test and chi-square test were performed for statistical analysis.Results The relative expression of TIPE3 mRNA in the colon cancer tissues was 0.719 (0.104 to 0.887),which was lower than that of tumor-adjacent tissues (4.770,1.732 to 6.800),and the difference was statistically significant (Z=-6.345,P＜0.05).There was no statistically significant difference in the expression of TIPE3 mRNA in colon cancer tissues between different gender,age and TNM stage (all P＞0.05).The expression of TIPE3 mRNA in group of patients with lymph node metastasis (0.113,0.061 to 0.375) was lower than group of patients without lymph node metastasis (0.489,0.327 to 0.956;Z=3.815,P＜0.01).The expression of TIPE3 mRNA of patients survived less than five years after operation (0.104,0.049 to 0.220) was lower than that of patients survived over five years (0.482,0.266 to 0.908;Z=-3.653,P＜0.01).The expression of TIPE3 mRNA of patients with recurrence after operation (0.188,0.091 to 0.493) was lower than that of patients without recurrence (0.409,0.233 to 1.010;Z=-2.431,P=0.015).The recurrence rate of TIPE3 mRNA high expression group in five years after operation was lower than that of TIPE3 mRNA low expression group (23.1％,6/26 vs 56.2％,18/32);and the difference was statistically significant (x2 =6.508,P＜0.05).The expression of TIPE3 at protein level of colon cancer tissues (44.6 ％,37/83) was lower than that of tumor-adjacent tissues (68.7 ％,57/83;x2 =8.004,P＜0.05).The expression of TIPE3 at protein level was not correlated with age and gender (both P＞0.05).The positive expression rate of patients at stage Ⅱ was higher than that of patients at stage Ⅲ (60.5％,23/38 vs 29.7％,1/37);and the difference was statistically significant (x2 =7.174,P＜ 0.05).The positive expression rate of TIPE3 in group of patients with lymph node metastasis was lower than that of groups of patients without lymph node metastasis (28.2％,11/39 vs 59.1％,26/44),and the difference was statistically significant (x2=7.983,P =0.005).Conclusions The expression of TIPE3 in colon cancer tissues is lower than that in tumor-adjacent tissues.Furthermore,it is correlated with lymph node metastasis,recurrence rate and survival rate.TIPE3 may be involved in the genesis,development,invasion and metastasis of colon cancer.

Effect and mechanism of TIPE3 interference plasmid on SW480 colorectal canc-er growth / 中国免疫学杂志

Objective:To study the effect of interference TIPE3 on the colon cancer cell growth by transfecting SW480 colon cancer cells with the TIPE3 interference plasmid were detected.Methods:Transfecting the constructed TIPE3-shRNA-pSIREN-RetroQ plasmid to SW480 cells.To determine the highest interference efficiency plasmid ,the mRNA and protein levels of recombined plasmid were detected by RT-PCR and Western blot separately and tested the cell proliferation with CCK 8.Meanwhile,apoptosis rate of SW480 cells was determined by flow cytometry assay with AnnexinV-FITC/PI.To further determined the effects of recombined plasmid on cell development ,the level of protein involved in proliferation and apoptosis were detected by Western blot .Results:The most effecient in-terference plasmids were successfully constructed.We found that the cell survival rate decreased when interference TIPE 3 gene express-ing in colorectal cancer cells .Flow cytometry indicated that interefering the expression of TIPE 3 would increase the sensitivity of SW 480 cell to apoptosis induced by aDR5ScFv.The results of Western blot showed that low expression of TIPE 3 would activate caspase3 and downregulate the expression of p-AKT,p-PDK1 and PCNA.Conclusion:Interference TIPE3 could promote apoptosis and inhibit prolif-eration in SW480 colon cancer cells .

Molecular insights into the binding of phosphoinositides to the TH domain region of TIPE proteins.

Phosphatidylinositols and their phosphorylated derivatives, phosphoinositides, play a central role in regulating diverse cellular functions. These phospholipids have been shown to interact with the hydrophobic TH domain of the tumor necrosis factor (TNF)-α-induced protein 8 (TIPE) family of proteins. However, the precise mechanism of interaction of these lipids is unclear. Here we report the binding mode and interactions of these phospholipids in the TH domain, as elucidated using molecular docking and simulations. Results indicate that phosphoinositides bind to the TH domain in a similar way by inserting their lipid tails in the hydrophobic cavity. The exposed head group is stabilized by interactions with critical positively charged residues on the surface of these proteins. Further MD simulations confirmed the dynamic stability of these lipids in the TH domain. This computational analysis thus provides insight into the binding mode of phospholipids in the TH domain of the TIPE family of proteins. Graphical abstract A phosphoinositide (phosphatidylinositol 4-phosphate; PtdIns4P) docked to TIPE2.

TIPE family:biological activities and functions / 中国免疫学杂志

The TIPE( tumor necrosis factor-alpha-induced protein 8-like) family has been recently described as regulators of tu-morigenesis and inflammation .The family consists of four highly homologous members: TNFAIP8 ( tumor necrosis factor-α-induced protein 8), TIPE1 (TNFAIP8L1), TIPE2 (TNFAIP8L2) and TIPE3 (TNFAIP8L3).Although TNFAIP8 family share high degrees of sequence homology , the members have different histological expressions , biological functions and molecular targets .TNFAIP8 shows the functions of inhibiting bacterial infection and promoting tumor migration .As a negative regulator of immunity and inflammation , TIPE2 is also an inhibitor of the oncogenic Ras in some neoplastic diseases .TIPE1 can induce cell apoptosis and inhibit tumor .TIPE3 is the transfer protein of phosphoinositide second messengers and can promote cancer .Emerging studies show TIPE family play important regulatory roles in many diseases;however, specific biological activities and exact molecular mechanisms need to be further elucidated .

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.