Tripartite Motif Protein Family Research Articles

The role of TRIM family proteins in the regulation of cancer stem cell self-renewal.

The tripartite‐motif (TRIM) family of proteins represents one of the largest classes of putative single protein RING‐finger E3 ubiquitin ligases. The members of this family are characterized by an N‐terminal TRIM motif containing one RING‐finger domain, one or two zinc‐finger domains called B boxes (B1 box and B2 box), and a coiled‐coil region. The TRIM motif can be found in isolation or in combination with a variety of C‐terminal domains, and based on C‐terminus, TRIM proteins are classified into 11 distinct groups. Because of the complex nature of TRIM proteins, they are implicated in a variety of cellular functions and biological processes, including regulation of cell proliferation, cell division and developmental processes, cancer transformation, regulation of cell metabolism, autophagocytosis, modification of chromatin status, regulation of gene transcription, post‐translational modifications, and interactions with pathogens. Here, we demonstrate the specific activities of TRIM family proteins that contribute to the cancer stem cell phenotype. A growing body of evidence demonstrates that several TRIM members guarantee the acquisition of stem cell properties and the ability to sustain stem‐like phenotype by cancer cells using distinct mechanisms. For other members, further work is needed to understand their full contribution to stem cell self‐renewal. Identification of TRIM proteins that possess the potential to serve as therapeutic targets may result in the development of new therapeutic strategies. Finally, these strategies may result in the disruption of the machinery of stemness acquisition, which may prevent tumor growth, progression, and overcome the resistance to anticancer therapies.

Whole exome sequencing reveals the maintained polyclonal nature from primary to metastatic malignant peripheral nerve sheath tumor in two patients with NF1.

BackgroundMalignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft tissue sarcomas with high metastatic rates and poor overall patient survival. There are currently no effective therapies, underscoring the pressing need to define the molecular etiologies that underlie MPNST progression. The aim of this study was to examine clonal progression and identify the molecular events critical for MPNST spread.MethodsIn two patients with temporally and spatially distinct metastatic lesions, we employed whole exome sequencing (WES) to elucidate the genetic events of clonal progression, thus identifying the molecular events critical for MPNST spread.ResultsFirst, we demonstrated shared clonal origins for the metastatic lesions relative to the primary tumors, which were maintained throughout the course of MPNST progression, supporting the conclusion that cancer cells with metastatic potential already exist in the primary neoplasm. Second, we discovered TRIM23, a member of the Tripartite Motif family of proteins, as a regulator of MPNST lung metastatic spread in vivo.ConclusionsThe ability to track the genomic evolution from primary to metastatic MPNST offers new insights into the sequence of genetic events required for tumor progression and has identified TRIM23 as a novel target for future study in this rare cancer.

Restriction of HIV-1 and other retroviruses by TRIM5.

Mammalian cells express a variety of innate immune proteins - known as restriction factors - which defend against invading retroviruses such as HIV-1. Two members of the tripartite motif protein family - TRIM5α and TRIMCyp - were identified in 2004 as restriction factors that recognize and inactivate the capsid shell that surrounds and protects the incoming retroviral core. Research on these TRIM5 proteins has uncovered a novel mode of non-self recognition that protects against cross-species transmission of retroviruses. Our developing understanding of the mechanism of TRIM5 restriction underscores the concept that core uncoating and reverse transcription of the viral genome are coordinated processes rather than discrete steps of the post-entry pathway of retrovirus replication. In this Review, we provide an overview of the current state of knowledge of the molecular mechanism of TRIM5-mediated restriction, highlight recent advances and discuss implications for the development of capsid-targeted antiviral therapeutics.

The novel gene TRIM44L from orange-spotted grouper negatively regulates the interferon response

Accumulated evidence suggests that some of the tripartite motif (TRIM) -family proteins function as critical regulators of carcinogenesis, immunity, and antiviral functions. TRIM44 is an atypical TRIM family protein that lacks the entire RING domain and has been demonstrated to play a crucial role in cancer and viral infection. To our knowledge, the role of TRIM44 in fish still remains largely unknown. Here, we cloned and characterized a novel TRIM44-like gene from orange spotted grouper (EcTRIM44L). Sequence analysis indicated that EcTRIM44L encoded a 393 amino acid peptide, which shared 81.44% and 51.02% identity with large yellow croaker (Larimichthys crocea) and zebrafish (Danio rerio), respectively. However, EcTRIM44L only exhibited 24.69% identity with the TRIM44 protein of humans (Homo sapiens). Moreover, EcTRIM44L contained two conserved domains, including a B-Box domain and a coiled-coil domain, but not a RING domain. Using fluorescence microscopy, we observed green fluorescence in the cytoplasm of the EcTRIM44L-EGFP transfected grouper spleen (GS) cells. As the infection proceeded, EcTRIM44L transcription was significantly up-regulated in red-spotted grouper nervous necrosis virus (RGNNV) infection, suggesting that EcTRIM44L might be involved in fish virus infections. The in vitro overexpression of EcTRIM44L significantly enhanced RGNNV replication, as demonstrated by the accelerated cytopathic effect (CPE) progression induced by RGNNV, as well as the increased expression of coat protein (CP) and RNA-dependent RNA polymerase (RdRp). The overexpression of EcTRIM44L significantly decreased the level of interferon (IFN) related signaling molecules and pro-inflammatory cytokine expression, suggesting that EcTRIM44L affected virus replication by negatively regulating the IFN response. In addition, the melanoma differentiation-associated protein 5 (MDA5) and mitochondrial antiviral-signaling protein (MAVS), but not mediator of IRF3 activation (MITA)-evoked IFN response was negatively regulated by EcTRIM44L. Together, for the first time, our results indicate that EcTRIM44L negatively regulates the interferon response against grouper RNA virus infection.

TRIM72 Immunohistochemical Expression Can Predict Relapse in Colorectal Carcinoma.

Large bowel adenocarcinoma is one of the most frequent human neoplasms and despite recent insights into the pathophysiology and molecular basis of this disease, mortality remains high in advanced and metastatic cases. Most guidelines recommend adjuvant chemotherapy for tumours involving lymph nodes, but not for patients with localized stage I or II disease. However, it is well known that approximately 20% of stage II colorectal carcinoma patients eventually recur, mainly with distant or peritoneal involvement and show bad prognosis. It would be important to predict which patients are at increased risk of recurrence to guide potential adjuvant therapy use in this controversial setting. In this sense, only microsatellite stability has been proposed as a predictive tool in some guidelines. The tripartite motif family protein 72 (TRIM72) is a ubiquitin ligase, involved in the cell membrane repair machinery and known to be associated to insulin resistance. Its potential role in colon cancer has recently been proposed. The aim of this study is to determine the potential predictive value of TRIM72 immunohistochemical expression in stage II colon carcinoma. We have retrospectively reviewed a series of 95 patients with stage II colon microsatellite stable carcinomas operated with a curative intent at a single large tertiary hospital in Madrid (Spain) between 2006 and 2012. None of the patients received adjuvant chemotherapy. We reviewed the histopathological slides and constructed a tissue microarray (TMA) of three representative areas to perform immunohistochemical staining for TRIM72. In our series 30 patients (31.7%) recurred after a median follow-up of 17.5months. Lack of immunohistochemical expression of TRIM72 in the tumor was significantly and independently associated to recurrence. A recent report by Chen et al. has shown that TRIM72 can be measured in plasma for colon carcinoma detection as an alternative to CEA or CA19.9, with lower levels in patients with carcinoma. Our report is the first one to show that lower immunohistochemical expression of TRIM72 predicts recurrence in colon stage II carcinoma. We feel this predictive influence can be related to its crucial role as a central regulator in many signaling pathways (PI3K-AKT, ERK). As an ubiquitin ligase, the lack of TRIM72 could increase the levels of several potential oncogenic molecules and therefore lead to a more aggressive phenotype. It remains to be shown whether chemotherapy could change the clinical behaviour of this bad prognosis group. We propose TRIM72 immunohistochemical analysis as a potential tool to predict recurrence risk in stage II colon carcinoma patients. Our results should be confirmed in larger series, but could open the way to management strategies refinement in this early stage group of patients.

Knockdown of TRIM27 expression suppresses the dysfunction of mesangial cells in lupus nephritis by FoxO1 pathway.

TRIM27 (tripartite motif-containing 27) is a member of the TRIM (tripartite motif) protein family and participates in a variety of biological processes. Some research has reported that TRIM27 was highly expressed in certain kinds of carcinoma cells and tissues and played an important role in the proliferation of carcinoma cells. However, whether TRIM27 takes part in the progression of lupus nephritis (LN) especially in cells proliferation remains unclear. Our study revealed that the overexpression of TRIM27 was observed in the kidneys of patients with LN, lupus mice and mesangial cells exposed to LN plasma which correlated with the proliferation of mesangial cells and ECM (extracellular matrix) deposition. Downregulation of TRIM27 expression suppressed the proliferation of mesangial cells and ECM accumulation in MRL/lpr mice and cultured human mesangial cells (HMCs) by regulating the FoxO1 pathway. Furthermore, the overexpression of FoxO1 remarkably decreased HMCs proliferation level and ECM accumulation in LN plasma-treated HMCs. In addition, the protein kinase B (Akt) signal pathway inhibitor LY294002 significantly reduced the expression of TRIM27 and inhibited the dysfunction of mesangial cells. These above data suggested that TRIM27 mediated abnormal mesangial cell proliferation in kidney of lupus and might be the potential target for treating mesangial cell proliferation of lupus nephritis.

The interplay between viruses and TRIM family proteins.

Novel therapeutic options are urgently needed to improve the global treatment of viral infections. Tripartite motif (TRIM) family proteins are involved in various biological and cellular functions including differentiation, development, proliferation, oncogenesis, innate immunity, and viral autophagy. Various TRIM proteins show antiviral properties against different viral infections and are now transitioning from ubiquitin proteins to an efficient and emerging therapeutic class of proteins. TRIM proteins combat viruses by targeting them at pre/post transcription levels. This review summarizes the comprehensive roles of different TRIM proteins along with their expression systems and their applications towards antiviral therapeutics.

The Role of Tripartite Motif Family Proteins in TGF-β Signaling Pathway and Cancer.

TGF-β signaling plays a tumor suppressive role in normal and premalignant cells but promotes tumor progression during the late stages of tumor development. The TGF-β signaling pathway is tightly regulated at various levels, including transcriptional and post-translational mechanisms. Ubiquitination of signaling components, such as receptors and Smad proteins is one of the key regulatory mechanisms of TGF-β signaling. Tripartite motif (TRIM) family of proteins is a highly conserved group of E3 ubiquitin ligase proteins that have been implicated in a variety of cellular functions, including cell growth, differentiation, immune response, and carcinogenesis. Recent emerging studies have shown that some TRIM family proteins function as important regulators in tumor initiation and progression. This review summarizes current knowledge of TRIM family proteins regulating the TGF-β signaling pathway with relevance to cancer.

TRIM22 regulates macrophage autophagy and enhances Mycobacterium tuberculosis clearance by targeting the nuclear factor-multiplicity κB/beclin 1 pathway.

Autophagy is a crucial host-defense mechanism against Mycobacterium tuberculosis (Mtb) infection by spanning innate and adaptive immune functions. TRIM22 is a member of tripartite motif family protein which involved in innate immunity and autophagy process. However, its role in the modulation of bacterial infection has not been investigated. Here, we demonstrated that TRIM22 is upregulated in a dose-dependent and time-dependent manner during Mtb infection of THP-1 cells. Downregulation of TRIM22 significantly decreased light chain 3 (LC3)-II protein level and the formation of LC3 puncta, while it markedly increased SQSTM1, a marker of autophagic degradation, in Mtb-infected THP-1 cells. What is more, enhanced bacterial survival was observed in TRIM22 knockdown THP-1 cells, while rapamycin abrogated this effect. In the presence of vector containing TRIM22 in THP-1 cells prior to infection, the survival of Mtb was decreased, while BafA restored this effect. Further study demonstrated that TRIM22 expression was regulated by MicroRNA-20b, and that TRIM22 regulates Mtb-infected THP-1 autophagy via the nuclear factor-κB/beclin 1 pathway. Using a nuclear factor-κB inhibitor BAY 11-7082, we found that TRIM22-induced high expression of LC3-II and the formation of LC3 was substantially attenuated, while the TRIM22-induced low expression of SQSTM1 was markedly increased in BAY 11-7082-treatment cells. In addition, the bacterial survival reduced by TRIM22 was significantly reversed by BAY 11-7082. Overall, these results suggest that TRIM22-augmented autophagy prevents intracellular Mtb to evade autophagic clearance, thereby inhibiting the persistence of Mtb infections.

Expression and significance of tripartite motif family proteins in hepatocellular carcinoma

Tripartite motif (TRIM) family, a very important protein family, has various functions in cellular biological processes including intracellular signal transduction, cell growth and apoptosis, innate immunity, autophagy and tumorigenesis. The specific expressions of TRIM in hepatocellular carcinoma are proved by many researches, which are closely related to the occurrence, metastasis and prognosis of hepatocellular carcinoma. TRIM are expected to be markers for the occurrence and development of hepatocellular carcinoma, and have broad prospects in the early diagnosis, therapy and prognosis of hepatocellular carcinoma. Key words: Carcinoma, hepatocellular; Tripartite motif family

Knockdown of TRIM31 suppresses proliferation and invasion of gallbladder cancer cells by down-regulating MMP2/9 through the PI3K/Akt signaling pathway

Tripartite motif (TRIM) 31, a member of the TRIM protein family, contributes to a wide range of biological processes and its altered expression exerts a non-negligible effect on multiple pathological conditions such as immunological disorders and retroviral protective activity. Recently, increasing evidence has demonstrated an important role of TRIM31 in the development of various cancers. However, the role of TRIM31 in gallbladder cancer (GBC) remains unclear. In this study, we showed that TRIM31 was elevated in GBC tissues and cell lines and associated with the clinicopathological features of GBC patients. Down-regulation of TRIM31 suppressed GBC cell proliferation, migration and invasion in vitro as well as inhibited tumor growth and metastasis in vivo. In addition, knockdown of TRIM31 reduced the expression of MMP2, MMP9 and p-Akt. Taken together, these findings indicated that knockdown of TRIM31 suppressed proliferation and invasion of GBC cells and was associated with PI3K/Akt signaling inactivation. Thus, TRIM31 may be a potential therapeutic target for the treatment of GBC.

Modulating Cytoskeletal Structure And Cellular Signaling To Target Neuron Cell Membrane Repair

Most cells in the human body have the capacity to reseal their cellular membranes following disruption of the lipid bilayer. The cell signaling response regulating membrane repair is dependent on changes in the mechanical tension on the plasma membrane. Increased mechanical tension on the membrane can lead to membrane disruptions remaining open and thus preventing resealing of the membrane. Disruption of these membrane repair processes can result in a number of diseases including muscular dystrophy, Alzheimer's and neurodegeneration. Conversely, if membrane repair can be elevated in striated muscle or neuronal tissues, this response could potentially minimize cell death in neuromuscular diseases and alleviate the progression of these disease states. We have previously shown that tripartite motif (TRIM) 72, also known as mitsugumin 53 (MG53), can increase plasma membrane repair in skeletal and cardiac muscle and in non‐muscle cell types where it is not usually expressed. Our recent results indicate that there are distinct TRIM72/MG53 regulated cellular signaling events that control the membrane repair response in multiple cell types. This observation led us to screen for novel TRIM family proteins that may be able to mediate membrane repair in neuronal cells. We found that TRIM2 transfected cells show an increased capacity for membrane resealing following multi‐photon laser injury and that knockdown of TRIM2 decreases membrane repair. Because TRIM2 is highly expressed in the nervous system and was previously shown to regulate neurofilaments (NFL), the objective of this study is to prove that TRIM2 protects against membrane damage in neurons through regulation of neurofilament ubiquitination and that disruption of TRIM2 or NFL leads to compromised membrane repair and neuron cell death. Through confocal microscopy, we have shown that TRIM2 co‐localizes with NFL in neurons. Following injury to the cell this association is altered, leading to changes in the subcellular localization of TRIM2 and an apparent reorganization of the neurofilament cytoskeleton. Given the extensive expression of TRIM2 in the nervous system, it may represent a good candidate for targeting membrane repair in the treatment of a variety of neurodegenerative diseases.Support or Funding InformationAmerican Heart Association, National Institutes of Health, National Institute of Neurological Disorders and Stroke (NINDS)‐sponsored T32, and Jain FoundationThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Abstract P3-07-06: TRIM44 is a possible poor prognostic factor for breast cancer patients and positively regulates NF-κB signaling pathway

Abstract [Background] Many of the tripartite motif (TRIM) proteins, like Efp/TRIM25 which was identified by our group previously (Nature 417, 871-875, 2002), function as E3 ubiquitin ligases, and are thought to be involved in various physiological and pathological processes such as immunity and oncogenesis. In regard to tripartite motif containing 44 (TRIM44), which is an atypical TRIM family protein lacking RING finger domain, some evidences suggest that it is implicated in the progression of several human malignancies. But its pathophysiological significance in breast cancer remains unknown. [Methods] In the present study, immunohistochemical analysis using anti-TRIM44 antibody was performed in clinical breast cancer tissues from 129 patients with the approval of institutional ethical committees (approval number: 845). We then explored the pathophysiological role of TRIM44 in breast cancer by modulating TRIM44 expression in MCF-7 and MDA-MB-231 breast cancer cells. [Results] TRIM44 strong immunoreactivity was significantly associated with nuclear grade, distant disease-free survival and overall survival of the breast cancer patients. With multivariate analysis it was shown that the TRIM44 status was an independent prognostic factor for distant disease-free survival and overall survival. The proliferation of MCF-7 and MDA-MB-231 cells was significantly decreased by siRNA-mediated TRIM44 knockdown. TRIM44 knockdown also suppressed migration of MDA-MB-231 cells. Microarray analysis and qRT-PCR revealed that TRIM44 knockdown upregulated CDK19 (Cyclin Dependent Kinase 19), which is reported to be a tumor suppressor gene, whereas downregulated MMP1 (Matrix Metallopeptidase 1) in MDA-MB-231 cells. Notably, TRIM44 knockdown impaired nuclear factor-kappa B (NF-κB)-mediated transcriptional activity stimulated by tumor necrosis factor α (TNFα). Moreover, TRIM44 knockdown substantially attenuated the TNFα-dependent phosphorylation of p65 subunit of NF-κB and IκBα in both MCF-7 and MDA-MB-231 cells. [Discussion] Our clinical study showed that prognosis of breast cancer patients is correlated with the immunoreactivity detected by anti-TRIM44 antibody. This result suggested that expression of TRIM44 protein could be used as a potential biomarker of breast cancer. We demonstrated that NF-κB signaling pathway is modulated by TRIM44. Since NF-κB augmentation is shown to be related to aggressive character of breast cancer, stimulation of NF-κB signaling with TRIM44 might be underlying mechanism of poor prognosis. Our in vitro study showed TRIM44 knockdown caused attenuated proliferation and migration of breast cancer cells, raising the possibility of TRIM44 as a potential therapeutic target for breast cancer. These findings provide new clues to develop alternative effective strategies for breast cancer management. Citation Format: Kawabata H, Azuma K, Ikeda K, Sugitani I, Kinowaki K, Fujii T, Osaki A, Saeki T, Horie-Inoue K, Inoue S. TRIM44 is a possible poor prognostic factor for breast cancer patients and positively regulates NF-κB signaling pathway [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-07-06.

Serum Levels of TRIM72 Are Lower among Patients with Colon Cancer: Identification of a Potential Diagnostic Marker.

Colon cancer is one of the most common malignancies causing the majority of cancer-related deaths worldwide. The tripartite motif family protein 72 (TRIM72), also known as mitsugumin 53, acts as an E3 ubiquitin ligase. TRIM72 is involved in insulin resistance and metabolic syndrome, which are risk factors of colon cancer. However, the correlation between TRIM72 and colon cancer remains unknown. In the present study, we explored the expression profile of TRIM72 in colon cancer tissues and the diagnostic value of serum TRIM72 in colon cancer. The receiver operating characteristic (ROC) curves were applied for evaluating the diagnostic value of serum TRIM72. We thus found that immunoreactive TRIM72 levels were significantly lower in colon cancer tissues than those in normal colon tissues. Moreover, serum TRIM72 levels were significantly lower in colon cancer patients than those in healthy volunteers. Importantly, the lower serum TRIM72 levels were associated with advanced clinical stage, lymph node, and distant metastases in colon cancer patients. The ROC curve analysis showed that serum TRIM72 has a superior diagnostic value (the area under the curve (AUC) = 0.829) than the traditional tumor biomarkers, carcinoembryonic antigen (CEA) (AUC = 0.707) and carbohydrate antigen 19-9 (CA199) (AUC = 0.750), and the combination of TRIM72 with CEA and CA199 showed the best diagnostic value for colon cancer (AUC = 0.928). In conclusion, serum TRIM72 may be a potential biomarker for the diagnosis and the prognosis of colon cancer.

Gene expression profiling of the TRIM protein family reveals potential biomarkers for indicating tuberculosis status

Tripartite motif (TRIM) family proteins play important regulatory roles in innate immune responses, the dysregulation of which cause several infectious diseases. However, the role and function of TRIM family proteins during tuberculosis (TB) infection remains unclear. In this study, we employed real-time quantitative PCR to profile the transcript levels of 72 TRIM genes from a cohort of 5 active TB patients, 5 latent tuberculosis infection (LTBI) subjects, and 5 healthy controls (HCs) in an initial discovery phase. The notable TRIM genes were assessed by in vitro cell infection experiments and further validated in another independent cohort (36 active TB, 24 LTBI and 28 HCs). The receiver operating characteristic (ROC) was used to analyze the diagnostic power of these TRIM genes. Our results revealed that 20 TRIM genes were decreased in active TB compared to LTBI and HCs. In addition, TRIM4, 16, 27, 32, 35, 46, 47, 65 and 68 were further shown to be downregulated in Mycobacterium smegmatis-infected macrophages and were found to be closely correlated with infection time and initial bacteria loads. Furthermore, the ROC analyses showed that TRIM4, 27 and 65 all exhibited the highest areas under the curve (AUC) values of 1.00 in discriminating active TB from LTBI and HCs. Moreover, TRIM27 combined with TRIM32 for an improved AUC value of 0.81 in discriminating LTBI from HCs. These results suggest that TRIM gene dysregulation might be involved in the pathogenesis of TB and that these genes could serve as potential biomarkers for indicating TB status.

BCG Increased Membrane Expression of TRIM59 Through the TLR2/ TLR4/IRF5 Pathway in RAW264.7 Macrophages.

In our previous study, we showed that Bacillus Calmette-Guerin (BCG)- activated macrophages have the ability to directly kill tumor cells. One of the main properties of these macrophages is the high expression of tripartite motif family protein 59 (TRIM59). This study was conducted to investigate the mechanism of BCG-induced TRIM59 expression on macrophages and to identify the subcellular localization of TRIM59. TRIM59 expression and TNF-α secretion were compared in RAW264.7 macrophage cells that were stimulated using BCG with or without Toll-like receptor 2/4 (TLR2/4)-neutralizing antibodies. Next, small interfering RNA (siRNA) was used to down-regulated interferon regulatory factor 5 (IRF5) gene expression in RAW264.7 cells. Transfected cells were stimulated with BCG, after which TRIM59 expression and TNF-α secretion were evaluated in cells pre-treated with siRNA or scramble control. After treatments, supernatants were co-cultured with MCA207, and cell viabilities were determined. Moreover, BCG-stimulated RAW264.7 cells were stained for TRIM59 and F4/80 expression. In this study, we showed that TRIM59 was expressed on the membrane of RAW264.7 cells. After blocking TLR2/4, treatment with BCG failed to induce the expression of TRIM59, IRF5, and TNF-α on RAW264.7 cells. In addition, down-regulation of IRF5 inhibited TRIM59 and TNF-α expression. Our study showed that TRIM59 is a membrane protein, and that BCG treatment upregulated TRIM59 expression on macrophages via TLR2/4 and IRF5 pathways.

TRIM31 is upregulated in hepatocellular carcinoma and promotes disease progression by inducing ubiquitination of TSC1–TSC2 complex

Tripartite motif (TRIM) 31 is a member of the tripartite motif-containing protein family, and TRIM family proteins are involved in a broad range of biological and pathological processes. However, the role of TRIM31 in hepatocellular carcinoma (HCC) progression is not known. Here we demonstrated that TRIM31 expression was significantly upregulated in liver cancer tissues compared with paired distal non-cancerous liver tissues from HCC patients, and its overexpression was significantly correlated with advanced disease status. Both gain and loss of function assay verified that TRIM31 promoted the malignant behaviors of HCC cells through overactivation of mammalian target of rapamycin complex1 (mTORC1) pathway. We further demonstrated that TRIM31 exerted its oncogenic effect by directly interacting with the tuberous sclerosis complex (TSC) 1 and TSC2 complex, the upstream suppressor of mTORC1 pathway, and promoting the E3 ligase-mediated K48-linked ubiquitination and degradation of this complex. In conclusion, this study demonstrated TRIM31 could promote HCC progression by targeting TSC1-TSC2 complex for degradation and further overactivating mTORC1 pathway. Thus, it revealed a novel molecular mechanism of HCC progression and indicated a potential therapeutic strategy against HCC by targeting TRIM31.

TRIM44 Is a Poor Prognostic Factor for Breast Cancer Patients as a Modulator of NF-κB Signaling.

Many of the tripartite motif (TRIM) proteins function as E3 ubiquitin ligases and are assumed to be involved in various events, including oncogenesis. In regard to tripartite motif-containing 44 (TRIM44), which is an atypical TRIM family protein lacking the RING finger domain, its pathophysiological significance in breast cancer remains unknown. We performed an immunohistochemical study of TRIM44 protein in clinical breast cancer tissues from 129 patients. The pathophysiological role of TRIM44 in breast cancer was assessed by modulating TRIM44 expression in MCF-7 and MDA-MB-231 breast cancer cells. TRIM44 strong immunoreactivity was significantly associated with nuclear grade (p = 0.033), distant disease-free survival (p = 0.031) and overall survival (p = 0.027). Multivariate analysis revealed that the TRIM44 status was an independent prognostic factor for distant disease-free survival (p = 0.005) and overall survival (p = 0.002) of patients. siRNA-mediated TRIM44 knockdown significantly decreased the proliferation of MCF-7 and MDA-MB-231 cells and inhibited the migration of MDA-MB-231 cells. Microarray analysis and qRT–PCR showed that TRIM44 knockdown upregulated CDK19 and downregulated MMP1 in MDA-MB-231 cells. Notably, TRIM44 knockdown impaired nuclear factor-kappa B (NF-κB)-mediated transcriptional activity stimulated by tumor necrosis factor α (TNFα). Moreover, TRIM44 knockdown substantially attenuated the TNFα-dependent phosphorylation of the p65 subunit of NF-κB and IκBα in both MCF-7 and MDA-MB-231 cells. TRIM44 would play a role in the progression of breast cancer by promoting cell proliferation and migration, as well as by enhancing NF-κB signaling.

Study mechanism of transmembrane 7 superfamily member 4 gene by real-time quantitative polymerase chain reaction array test in bresat cancer

Objective To explore the relationship between transmembrane 7 superfamily member 4 (TM7SF4) gene and breast cancer signal pathway of proliferation, invasion and metastasis. Methods After downexpressed TM7SF4 gene in michigan cancer foundation-7 (MCF-7) breast cell, screening high correlation functional gene and signal pathway by Real-time quantitative polymerase chain reaction array (qPCR array). Results After down-expressed TM7SF4 gene, there were 17 differentially expressed genes in screened 91 genes, TM7SF4 was closely related to 5 genes in the 17 kinds of differentially expressed genes using gene enrichment analysis. TM7SF4 geng was also related to tripartite motif protein family 24 (TRIM24) and tumor suppressor protein (TP53). In TRIM24 gene sets, CD44 variant 6 (CD44v6), cyclin dependent kinase inhibitor 1A (CDKN1A), Caspase-1 (CASP1) and insulin like growth factor 2 (IGF2) were obviously increased by TRIM24 signal pathway (P=0.006, 0.001, 0.002, 0.001); In TP53 gene sets, B-cell lymphoma-2 (bcl-2)-associated X (bax), CDKN1A and CASP1 were significantly increased by TP53 signal pathway (P=0.004, 0.001, 0.002). Conclusion TM7SF4 gene develops its role by TRIM24 and TP53 signal pathways in breast cancer cell line. Key words: Real-time quantitative polymerase chain reaction array; Breast cancer; Signal pathway

Expression profiling of TRIM protein family in THP1-derived macrophages following TLR stimulation

Activated macrophages play an important role in many inflammatory diseases including septic shock and atherosclerosis. However, the molecular mechanisms limiting macrophage activation are not completely understood. Members of the tripartite motif (TRIM) family have recently emerged as important players in innate immunity and antivirus. Here, we systematically analyzed mRNA expressions of representative TRIM molecules in human THP1-derived macrophages activated by different toll-like receptor (TLR) ligands. Twenty-nine TRIM members were highly induced (>3 fold) by one or more TLR ligands, among which 19 of them belong to TRIM C-IV subgroup. Besides TRIM21, TRIM22 and TRIM38 were shown to be upregulated by TLR3 and TLR4 ligands as previous reported, we identified a novel group of TRIM genes (TRIM14, 15, 31, 34, 43, 48, 49, 51 and 61) that were significantly up-regulated by TLR3 and TLR4 ligands. In contrast, the expression of TRIM59 was down-regulated by TLR3 and TLR4 ligands in both human and mouse macrophages. The alternations of the TRIM proteins were confirmed by Western blot. Finally, overexpression of TRIM59 significantly suppressed LPS-induced macrophage activation, whereas siRNA-mediated knockdown of TRIM59 enhanced LPS-induced macrophage activation. Taken together, the study provided an insight into the TLR ligands-induced expressions of TRIM family in macrophages.