TRIMming p53's anticancer activity

Latest News from the "Guardian": p53 Directly Activates Asymmetric Stem Cell Division Regulators

Since its discovery in 1979, the human tumor suppressor gene TP53-also known as the "guardian of the genome"-has been the subject of intense research. Mutated in most human cancers, TP53 has traditionally been considered a key fighter against stress factors by trans-activating a network of target genes that promote cell cycle arrest, DNA repair, or apoptosis. Intriguingly, over the past years, novel non-canonical functions of p53 in unstressed cells have also emerged, including the mode of stem cell division regulation. However, the mechanisms by which p53 modulates these novel functions remain incompletely understood. In a recent work, we found that Drosophila p53 controls asymmetric stem cell division (ASCD) in neural stem cells by transcriptionally activating core ASCD regulators, such as the conserved cell-fate determinants Numb and Brat (NUMB and TRIM3/TRIM2/TRIM32 in humans, respectively). In this short communication, we comment on this new finding, the mild phenotypes associated with Drosophila p53 mutants in this context, as well as novel avenues for future research.

Tripartite motif-containing protein 26 promotes colorectal cancer growth by inactivating p53

Tripartite motif-containing protein 26 (TRIM26) is an E3 ubiquitin ligase that exhibits divergent roles in various cancer types (oncogenic and anti-oncogenic). This study investigates the interaction of TRIM26 with the tumor suppressor protein p53 in colorectal cancer (CRC) cells by performing a comprehensive set of biochemical, cell-based assays, and xenograft experiments. As a result, we found that overexpression of TRIM26 significantly enhances CRC cell proliferation and colony formation, while knockdown of TRIM26 suppresses these processes. Xenograft experiments further validated the tumor-promoting role of TRIM26 in CRC. Supporting this is that TRIM26 is highly expressed in human CRC tissues as revealed by our analysis of the TCGA database. Biochemically, TRIM26 directly bound to the C-terminus of p53 and facilitated its ubiquitination, resulting in proteolytic degradation and attenuated p53 activity independently of MDM2. Also, TRIM26 increased the MDM2-mediated ubiquitination of p53 by binding to MDM2's C-terminus. This study uncovers the oncogenic potential of TRIM26 in CRC by inhibiting p53 function. Through its ubiquitin ligase activity, TRIM26 destabilizes p53, consequently promoting CRC cell proliferation and tumor growth. These findings shed light on the complex involvement of TRIM26 in cancer and identify this ubiquitin ligase as a potential therapeutic target for future development of CRC treatment.

Exploring the Mechanisms, Biomarkers, and Therapeutic Targets of TRIM Family in Gastrointestinal Cancer

Gastrointestinal region (GI) cancers are closely linked to the ubiquitination system, with the E3 ubiquitin ligase playing a crucial role by targeting various substrates. As E3 ubiquitin ligases, proteins of tripartite motif (TRIM) family play a role in cancer signaling, development, apoptosis, and formation. These proteins regulate diverse biological activities and signaling pathways. This study comprehensively outlines the functions of TRIM proteins in gastrointestinal physiology, contributing to our knowledge of the molecular pathways involved in gastrointestinal tumors. Gastrointestinal region (GI) cancers are closely linked to the ubiquitination system, with the E3 ubiquitin ligase playing a crucial role by targeting various substrates.

TRIM59-mediated ferroptosis enhances neuroblastoma development and chemosensitivity through p53 ubiquitination and degradation

Neuroblastoma, predominantly afflicting young individuals, is characterized as an embryonal tumor, with poor prognosis primarily attributed to chemoresistance. This study delved into the impact of tripartite motif (TRIM) 59, an E3 ligase, on neuroblastoma development and chemosensitivity through mediating ferroptosis and the involvement of the tumor suppressor p53. Clinical samples were assessed for TRIM59 and p53 levels to explore their correlation with neuroblastoma differentiation. In neuroblastoma cells, modulation of TRIM59 expression, either through overexpression or knockdown, was coupled with doxorubicin hydrochloride (DOX) or ferrostatin-1 (Fer-1) therapy. In vivo assessments examined the influence of TRIM59 knockdown on neuroblastoma chemosensitivity to DOX. Co-immunoprecipitation and ubiquitination assays investigated the association between TRIM59 and p53. Proliferation was gauged with Cell Counting Kit-8, lipid reactive oxygen species (ROS) were assessed via flow cytometry, and protein levels were determined by Western blotting. TRIM59 expression was inversely correlated with neuroblastoma differentiation and positively linked to cell proliferation in response to DOX. Moreover, TRIM59 impeded lipid ROS generation and ferroptosis by directly interacting with p53, promoting its ubiquitination and degradation in DOX-exposed neuroblastoma cells. Fer-1 countered the impact of TRIM59 knockdown on neuroblastoma, while TRIM59 knockdown enhanced the therapeutic efficacy of DOX in xenograph mice. This study underscores TRIM59 as an oncogene in neuroblastoma, fostering growth and chemoresistance by suppressing ferroptosis through p53 ubiquitination and degradation. TRIM59 emerges as a potential strategy for neuroblastoma therapy.

TRIM25 targets p300 for degradation

p300 is an important transcriptional co-factor. By stimulating the transfer of acetyl residues onto histones and several key transcription factors, p300 enhances transcriptional initiation and impacts cellular processes including cell proliferation and cell division. Despite its importance for cellular homeostasis, its regulation is poorly understood. We show that TRIM25, a member of the TRIM protein family, targets p300 for proteasomal degradation. However, despite TRIM25's RING domain and E3 activity, degradation of p300 by TRIM25 is independent of TRIM25-mediated p300 ubiquitination. Instead, TRIM25 promotes the interaction of p300 with dynein, which ensures a microtubule-dependent transport of p300 to cellular proteasomes. Through mediating p300 degradation, TRIM25 affects p300-dependent gene expression.

The role of TRIM25 in the occurrence and development of cancers and inflammatory diseases

The tripartite motif (TRIM) family proteins are a group of proteins involved in different signaling pathways. The changes in the expression regulation, function, and signaling of this protein family are associated with the occurrence and progression of a wide range of disorders. Given the importance of these proteins in pathogenesis, they can be considered as potential therapeutic targets for many diseases. TRIM25, as an E3-ubiquitin ligase, is involved in the development of various diseases and cellular mechanisms, including antiviral innate immunity and cell proliferation. The clinical studies conducted on restricting the function of this protein have reached promising results that can be further evaluated in the future. Here, we review the regulation of TRIM25 and its function in different diseases and signaling pathways, especially the retinoic acid-inducible gene-I (RIG-I) signaling which prompts many kinds of cancers and inflammatory disorders.

Comprehensive Analysis of the Prognostic Significance of the TRIM Family in the Context of TP53 Mutations in Cancers

The p53 protein is an important tumor suppressor, and TP53 mutations are frequently associated with poor prognosis in various cancers. Mutations in TP53 result in a loss of p53 function and enhanced expression of cell cycle genes, contributing to the development and progression of cancer. Meanwhile, several tripartite motif (TRIM) proteins are known to regulate cell growth and cell cycle transition. However, the prognostic values between TP53 and TRIM family genes in cancer are unknown. In this study, we analyzed the relationship between the TP53 mutations and TRIM family proteins and evaluated the prognostic significance of TRIM family proteins in cancer patients with P53 mutations. Our findings identified specific TRIM family members that are upregulated in TP53 mutant tumors and are associated with the activation of genes related to a cell-cycle progression in the context of TP53 mutations.

TRIM8: a double-edged sword in glioblastoma with the power to heal or hurt

Glioblastoma multiforme (GBM) is an aggressive primary brain tumor and one of the most lethal central nervous system tumors in adults. Despite significant breakthroughs in standard treatment, only about 5% of patients survive 5 years or longer. Therefore, much effort has been put into the search for identifying new glioma-associated genes. Tripartite motif-containing (TRIM) family proteins are essential regulators of carcinogenesis. TRIM8, a member of the TRIM superfamily, is abnormally expressed in high-grade gliomas and is associated with poor clinical prognosis in patients with glioma. Recent research has shown that TRIM8 is a molecule of duality (MoD) that can function as both an oncogene and a tumor suppressor gene, making it a "double-edged sword" in glioblastoma development. This characteristic is due to its role in selectively regulating three major cellular signaling pathways: the TP53/p53-mediated tumor suppression pathway, NFKB/NF-κB, and the JAK-STAT pathway essential for stem cell property support in glioma stem cells. In this review, TRIM8 is analyzed in detail in the context of GBM and its involvement in essential signaling and stem cell-related pathways. We also discuss the basic biological activities of TRIM8 in macroautophagy/autophagy, regulation of bipolar spindle formation and chromosomal stability, and regulation of chemoresistance, and as a trigger of inflammation.

Pan-cancer illumination of TRIM gene family reveals immunology regulation and potential therapeutic implications

BACKGROUND

The tripartite motif (TRIM) proteins function as important regulators in innate immunity, tumorigenesis, cell differentiation and ontogenetic development. However, we still lack knowledge about the genetic and transcriptome alterations landscape of TRIM proteins across cancer types.

METHODS

We comprehensively reviewed and characterized the perturbations of TRIM genes across > 10,000 samples across 33 cancer types. Genetic mutations and transcriptome of TRIM genes were analyzed by diverse computational methods. A TRIMs score index was calculated based on the expression of TRIM genes. The correlation between TRIMs scores and clinical associations, immune cell infiltrations and immunotherapy response were analyzed by correlation coefficients and gene set enrichment analysis.

RESULTS

Alterations in TRIM genes and protein levels frequently emerge in a wide range of tumors and affect expression of TRIM genes. In particular, mutations located in domains are likely to be deleterious mutations. Perturbations of TRIM genes are correlated with expressions of immune checkpoints and immune cell infiltrations, which further regulated the cancer- and immune-related pathways. Moreover, we proposed a TRIMs score index, which can accurately predict the clinical outcome of cancer patients. TRIMs scores of patients are correlated with clinical survival and immune therapy response across cancer types. Identifying the TRIM genes with genetic and transcriptome alterations will directly contribute to cancer therapy in the context of predictive, preventive, and personalized medicine.

CONCLUSIONS

Our study provided a comprehensive analysis and resource for guiding both mechanistic and therapeutic analyses of the roles of TRIM genes in cancer.

TRIM family contribute to tumorigenesis, cancer development, and drug resistance

The tripartite-motif (TRIM) family represents one of the largest classes of putative single protein RING-finger E3 ubiquitin ligases. TRIM family is involved in a variety of cellular signaling transductions and biological processes. TRIM family also contributes to cancer initiation, progress, and therapy resistance, exhibiting oncogenic and tumor-suppressive functions in different human cancer types. Moreover, TRIM family members have great potential to serve as biomarkers for cancer diagnosis and prognosis. In this review, we focus on the specific mechanisms of the participation of TRIM family members in tumorigenesis, and cancer development including interacting with dysregulated signaling pathways such as JAK/STAT, PI3K/AKT, TGF-β, NF-κB, Wnt/β-catenin, and p53 hub. In addition, many studies have demonstrated that the TRIM family are related to tumor resistance; modulate the epithelial–mesenchymal transition (EMT) process, and guarantee the acquisition of cancer stem cells (CSCs) phenotype. In the end, we havediscussed the potential of TRIM family members for cancer therapeutic targets.

TRIM67 Suppresses TNFalpha-Triggered NF-kB Activation by Competitively Binding Beta-TrCP to IkBa

The transcription factor NF-κB plays an important role in modulation of inflammatory pathways, which are associated with inflammatory diseases, neurodegeneration, apoptosis, immune responses, and cancer. Increasing evidence indicates that TRIM proteins are crucial role in the regulation of NF-κB signaling pathways. In this study, we identified TRIM67 as a negative regulator of TNFα-triggered NF-κB activation. Ectopic expression of TRIM67 significantly represses TNFα-induced NF-κB activation and the expression of pro-inflammatory cytokines TNFα and IL-6. In contrast, Trim67 depletion promotes TNFα-induced expression of TNFα, IL-6, and Mcp-1 in primary mouse embryonic fibroblasts. Mechanistically, we found that TRIM67 competitively binding β-transducin repeat-containing protein (β-TrCP) to IκBα results inhibition of β-TrCP-mediated degradation of IκBα, which finally caused inhibition of TNFα-triggered NF-κB activation. In summary, our findings revealed that TRIM67 function as a novel negative regulator of NF-κB signaling pathway, implying TRIM67 might exert an important role in regulation of inflammation disease and pathogen infection caused inflammation.

TRIM50 Suppresses Pancreatic Cancer Progression and Reverses the Epithelial-Mesenchymal Transition via Facilitating the Ubiquitous Degradation of Snail1

Emerging evidence suggests that the tripartite motif (TRIM) family play important roles in tumor development and progression. Tripartite motif-containing 50 (TRIM50) is a member of the TRIM family, but little is known regarding its expression and potential functional roles in cancer. In this study, we first analyzed the expression pattern and clinical significance of TRIM50 in pancreatic cancer and found that TRIM50 expression is significantly reduced in pancreatic cancer tissues and its downregulation is associated with poor survival for pancreatic cancer patients. Functionally, TRIM50 overexpression in pancreatic cancer cells decreases their proliferation and motility capabilities and reverses the epithelial-mesenchymal transition (EMT) process, whereas TRIM50 depletion had the opposite effects. Mechanically, TRIM50 directly interacts with Snail1, a key regulator of EMT, and acts as an E3 ubiquitin ligase to target Snail1 for ubiquitous degradation. The function of TRIM50 in suppressing cell migration and EMT depends on TRIM50-promoted Snail1 degradation. In conclusion, our findings identify TRIM50 as a tumor suppressor that inhibits pancreatic cancer progression and reverses EMT via degrading Snail1 and provide new insights into the progression of pancreatic cancer.

TRIM Proteins in Colorectal Cancer: TRIM8 as a Promising Therapeutic Target in Chemo Resistance

Colorectal cancer (CRC) represents one of the most widespread forms of cancer in the population and, as all malignant tumors, often develops resistance to chemotherapies with consequent tumor growth and spreading leading to the patient’s premature death. For this reason, a great challenge is to identify new therapeutic targets, able to restore the drugs sensitivity of cancer cells. In this review, we discuss the role of TRIpartite Motifs (TRIM) proteins in cancers and in CRC chemoresistance, focusing on the tumor-suppressor role of TRIM8 protein in the reactivation of the CRC cells sensitivity to drugs currently used in the clinical practice. Since the restoration of TRIM8 protein levels in CRC cells recovers chemotherapy response, it may represent a new promising therapeutic target in the treatment of CRC.

TRIM47 promotes malignant progression of renal cell carcinoma by degrading P53 through ubiquitination

Background

Renal cell carcinoma (RCC) is one of the most common malignant tumors originating from the renal parenchymal urinary epithelial system. Tripartite motif 47 (TRIM47) is a member of the TRIM family proteins, which has E3 ligase activity and has been demonstrated to be involved in the occurrence and prognosis of many tumors. The main purpose of this study is to explore the role and potential mechanism of TRIM47 in promoting malignant biological behavior of RCC.

Materials and methods

TRIM47 mRNA and protein levels in human renal cancer and paired normal adjacent tissues were detected by qRT-PCR and Western blot. The effects of TRIM47 knockdown and overexpression in renal cell carcinoma cells on cell proliferation, invasion and xenograft tumor growth in nude mice were analyzed. The molecular mechanism was explored by mass spectrometric exploration,Western blot and immunoprecipitation assays.

Results

TRIM47 promoted RCC cell proliferation in vitro and in vivo as an oncogene. Mechanistically, TRIM47 exerted an E3 ligase activity by interacting with P53 protein to increase its ubiquitination and degradation, which further promoted the malignant biological behavior of RCC.

Conclusions

Our study demonstrated that the TRIM47-P53 axis played a functional role in RCC progression and suggested a potential therapeutic target for RCC.

TRIM proteins in lung cancer: Mechanisms, biomarkers and therapeutic targets

The tripartite motif (TRIM) family is defined by the presence of a Really Interesting New Gene (RING) domain, one or two B-box motifs and a coiled-coil region. TRIM proteins play key roles in many biological processes, including innate immunity, tumorigenesis, cell differentiation and ontogenetic development. Alterations in TRIM gene and protein levels frequently emerge in a wide range of tumors and affect tumor progression. As canonical E3 ubiquitin ligases, TRIM proteins participate in ubiquitin-dependent proteolysis of prominent components of the p53, NF-κB and PI3K/AKT signaling pathways. The occurrence of ubiquitylation events induced by TRIM proteins sustains internal balance between tumor suppressive and tumor promoting genes. In this review, we summarized the diverse mechanism of TRIM proteins responsible for the most common malignancy, lung cancer. Furthermore, we also discussed recent progress in both the diagnosis and therapeutics of tumors contributed by TRIM proteins.

Primary effusion lymphoma enhancer connectome links super-enhancers to dependency factors

Primary effusion lymphoma (PEL) has a very poor prognosis. To evaluate the contributions of enhancers/promoters interactions to PEL cell growth and survival, here we produce H3K27ac HiChIP datasets in PEL cells. This allows us to generate the PEL enhancer connectome, which links enhancers and promoters in PEL genome-wide. We identify more than 8000 genomic interactions in each PEL cell line. By incorporating HiChIP data with H3K27ac ChIP-seq data, we identify interactions between enhancers/enhancers, enhancers/promoters, and promoters/promoters. HiChIP further links PEL super-enhancers to PEL dependency factors MYC, IRF4, MCL1, CCND2, MDM2, and CFLAR. CRISPR knock out of MEF2C and IRF4 significantly reduces MYC and IRF4 super-enhancer H3K27ac signal. Knock out also reduces MYC and IRF4 expression. CRISPRi perturbation of these super-enhancers by tethering transcription repressors to enhancers significantly reduces target gene expression and reduces PEL cell growth. These data provide insights into PEL molecular pathogenesis.

Multifaceted Roles of TRIM Proteins in Colorectal Carcinoma

Colorectal cancer (CRC) is one of the most frequently diagnosed tumor in humans and one of the most common causes of cancer-related death worldwide. The pathogenesis of CRC follows a multistage process which together with somatic gene mutations is mainly attributed to the dysregulation of signaling pathways critically involved in the maintenance of homeostasis of epithelial integrity in the intestine. A growing number of studies has highlighted the critical impact of members of the tripartite motif (TRIM) protein family on most types of human malignancies including CRC. In accordance, abundant expression of many TRIM proteins has been observed in CRC tissues and is frequently correlating with poor survival of patients. Notably, some TRIM members can act as tumor suppressors depending on the context and the type of cancer which has been assessed. Mechanistically, most cancer-related TRIMs have a critical impact on cell cycle control, apoptosis, epithelial–mesenchymal transition (EMT), metastasis, and inflammation mainly through directly interfering with diverse oncogenic signaling pathways. In addition, some recent publications have emphasized the emerging role of some TRIM members to act as transcription factors and RNA-stabilizing factors thus adding a further level of complexity to the pleiotropic biological activities of TRIM proteins. The current review focuses on oncogenic signaling processes targeted by different TRIMs and their particular role in the development of CRC. A better understanding of the crosstalk of TRIMs with these signaling pathways relevant for CRC development is an important prerequisite for the validation of TRIM proteins as novel biomarkers and as potential targets of future therapies for CRC.

Tumor suppressor p53 cross-talks with TRIM family proteins

p53 is a key tumor suppressor. As a transcription factor, p53 accumulates in cells in response to various stress signals and selectively transcribes its target genes to regulate a wide variety of cellular stress responses to exert its function in tumor suppression. In addition to tumor suppression, p53 is also involved in many other physiological and pathological processes, e.g. anti-infection, immune response, development, reproduction, neurodegeneration and aging. To maintain its proper function, p53 is under tight and delicate regulation through different mechanisms, particularly the posttranslational modifications. The tripartite motif (TRIM) family proteins are a large group of proteins characterized by the RING, B-Box and coiled-coil (RBCC) domains at the N-terminus. TRIM proteins play important roles in regulation of many fundamental biological processes, including cell proliferation and death, DNA repair, transcription, and immune response. Alterations of TRIM proteins have been linked to many diseases including cancer, infectious diseases, developmental disorders, and neurodegeneration. Interestingly, recent studies have revealed that many TRIM proteins are involved in the regulation of p53, and at the same time, many TRIM proteins are also regulated by p53. Here, we review the cross-talk between p53 and TRIM proteins, and its impact upon cellular biological processes as well as cancer and other diseases.

The Janus Face of p53-Targeting Ubiquitin Ligases

The tumor suppressor p53 prevents tumorigenesis and cancer progression by maintaining genomic stability and inducing cell growth arrest and apoptosis. Because of the extremely detrimental nature of wild-type p53, cancer cells usually mutate the TP53 gene in favor of their survival and propagation. Some of the mutant p53 proteins not only lose the wild-type activity, but also acquire oncogenic function, namely “gain-of-function”, to promote cancer development. Growing evidence has revealed that various E3 ubiquitin ligases are able to target both wild-type and mutant p53 for degradation or inactivation, and thus play divergent roles leading to cancer cell survival or death in the context of different p53 status. In this essay, we reviewed the recent progress in our understanding of the p53-targeting E3 ubiquitin ligases, and discussed the potential clinical implications of these E3 ubiquitin ligases in cancer therapy.

TRIM E3 Ubiquitin Ligases in Rare Genetic Disorders

The TRIM family comprises proteins characterized by the presence of the tripartite motif composed of a RING domain, one or two B-box domains and a coiled-coil region. The TRIM shared domain structure underscores a common biochemical function as E3 ligase within the ubiquitination cascade. The TRIM proteins represent one of the largest E3 ligase families counting in human more than 70 members. These proteins are implicated in a plethora of cellular processes such as apoptosis, cell cycle regulation, muscular physiology, and innate immune response. Consistently, their alteration results in several pathological conditions emphasizing their medical relevance. Here, the genetic and pathogenetic mechanisms of rare disorders directly caused by mutations in TRIM genes will be reviewed. These diseases fall into different pathological areas, from malformation birth defects due to developmental abnormalities, to neurological disorders and progressive teenage neuromuscular disorders. In many instances, TRIM E3 ligases act on several substrates thus exerting pleiotropic activities: the need of unraveling disease-specific TRIM pathways for a precise targeting therapy avoiding dramatic side effects will be discussed.

TRIM67 Activates p53 to Suppress Colorectal Cancer Initiation and Progression

Tripartite motif (TRIM) family proteins participate in a variety of important cellular processes, including apoptosis, cell-cycle arrest, DNA repair, and senescence. In this study, we demonstrated that a novel TRIM family member, TRIM67, was commonly silenced in colorectal cancer and its downregulation was associated with poor survival. Trim67 knockout in Apc^Min/+ mice increased the incidence, multiplicity, and burden of colorectal tumors. Similarly, colon-specific knockout of Trim67 significantly accelerated azoxymethane-induced colorectal cancer in mice. RNA sequencing revealed that the antitumor effect of TRIM67 was mediated by activation of the p53 signaling pathway. TRIM67 interacted directly with the C-terminus of p53, inhibiting p53 degradation by its ubiquitin ligase MDM2. TRIM67 was also a transcriptional target of p53; upon cellular stress, p53 bound to the TRIM67 promoter and induced significant upregulation of TRIM67, thereby forming a TRIM67/p53 self-amplifying loop that boosts p53-induced cell growth inhibition and apoptosis. Consequently, loss of this p53-positive regulatory program profoundly compromised p53-mediated responses to chemotherapy-induced DNA damage. Dampened p53 response was also observed in tumors of Trim67 knockout mice and Trim67 knockout embryonic fibroblasts. TRIM67 reactivation restored p53 activation and sensitized colorectal cancer cells to chemotherapy in vitro and in vivo. TRIM67 thus functions as a pivotal tumor suppressor in colorectal cancer and is a potential target for improving chemotherapy responsiveness. SIGNIFICANCE: The TRIM67/p53 axis represents a novel therapeutic target that could be harnessed to improve chemotherapy efficacy in colorectal cancer expressing wild-type p53 but with repressed p53 signaling.

Targeting Chemoresistant Tumors: Could TRIM Proteins-p53 Axis Be a Possible Answer?

Chemosensitivity is a crucial feature for all tumours so that they can be successfully treated, but the huge heterogeneity of these diseases, to be intended both inter- and intra-tumour, makes it a hard-to-win battle. Indeed, this genotypic and phenotypic variety, together with the adaptability of tumours, results in a plethora of chemoresistance acquisition mechanisms strongly affecting the effectiveness of treatments at different levels. Tripartite motif (TRIM) proteins are shown to be involved in some of these mechanisms thanks to their E3-ubiquitin ligase activity, but also to other activities they can exert in several cellular pathways. Undoubtedly, the ability to regulate the stability and activity of the p53 tumour suppressor protein, shared by many of the TRIMs, represents the preeminent link between this protein family and chemoresistance. Indeed, they can modulate p53 degradation, localization and subset of transactivated target genes, shifting the cellular response towards a cytoprotective or cytotoxic reaction to whatever damage induced by therapy, sometimes in a cellular-dependent way. The involvement in other chemoresistance acquisition mechanisms, independent by p53, is known, affecting pivotal processes like PI3K/Akt/NF-κB signalling transduction or Wnt/beta catenin pathway, to name a few. Hence, the inhibition or the enhancement of TRIM proteins functionality could be worth investigating to better understand chemoresistance and as a strategy to increase effectiveness of anticancer therapies.

TRIM59 promotes breast cancer motility by suppressing p62-selective autophagic degradation of PDCD10

Cancer cells adopt various modes of migration during metastasis. How the ubiquitination machinery contributes to cancer cell motility remains underexplored. Here, we report that tripartite motif (TRIM) 59 is frequently up-regulated in metastatic breast cancer, which is correlated with advanced clinical stages and reduced survival among breast cancer patients. TRIM59 knockdown (KD) promoted apoptosis and inhibited tumor growth, while TRIM59 overexpression led to the opposite effects. Importantly, we uncovered TRIM59 as a key regulator of cell contractility and adhesion to control the plasticity of metastatic tumor cells. At the molecular level, we identified programmed cell death protein 10 (PDCD10) as a target of TRIM59. TRIM59 stabilized PDCD10 by suppressing RING finger and transmembrane domain-containing protein 1 (RNFT1)-induced lysine 63 (K63) ubiquitination and subsequent phosphotyrosine-independent ligand for the Lck SH2 domain of 62 kDa (p62)-selective autophagic degradation. TRIM59 promoted PDCD10-mediated suppression of Ras homolog family member A (RhoA)-Rho-associated coiled-coil kinase (ROCK) 1 signaling to control the transition between amoeboid and mesenchymal invasiveness. PDCD10 overexpression or administration of a ROCK inhibitor reversed TRIM59 loss-induced contractile phenotypes, thereby accelerating cell migration, invasion, and tumor formation. These findings establish the rationale for targeting deregulated TRIM59/PDCD10 to treat breast cancer.

TRIM Proteins and Their Roles in Antiviral Host Defenses

Tripartite motif (TRIM) proteins are a versatile family of ubiquitin E3 ligases involved in a multitude of cellular processes. Studies in recent years have demonstrated that many TRIM proteins play central roles in the host defense against viral infection. While some TRIM proteins directly antagonize distinct steps in the viral life cycle, others regulate signal transduction pathways induced by innate immune sensors, thereby modulating antiviral cytokine responses. Furthermore, TRIM proteins have been implicated in virus-induced autophagy and autophagy-mediated viral clearance. Given the important role of TRIM proteins in antiviral restriction, it is not surprising that several viruses have evolved effective maneuvers to neutralize the antiviral action of specific TRIM proteins. Here, we describe the major antiviral mechanisms of TRIM proteins as well as viral strategies to escape TRIM-mediated host immunity.

Downregulation of TRIM58 expression is associated with a poor patient outcome and enhances colorectal cancer cell invasion

TRIM58 is a member of the tripartite motif protein (TRIM) family of E3 ubiquitin ligases. Aberrant gene methylation of TRIM58 has been reported in liver and lung cancer and indicates a poor patient prognosis. However, the expression level and functional role of TRIM58 in colorectal cancer (CRC) have yet to be elucidated. In the present study, we found that TRIM58 expression was significantly suppressed in human CRC and was inversely correlated with CRC progression. Additionally, overall survival was significantly reduced in patients with low TRIM58 expression in CRC tumors. In vitro studies demonstrated that ectopic TRIM58 overexpression strongly inhibited CRC cell invasion but had minimal effects on cell proliferation, colonization and migration. Furthermore, TRIM58 suppression enhanced the expression of epithelial-to-mesenchymal transition (EMT) and matrix metalloproteinase (MMP) genes. Thus, our findings suggest that TRIM58 is a potential prognostic marker of CRC and functions as a tumor-suppressor gene via inhibition of cancer cell invasion through EMT and MMP activation.

Stromal TRIM28-associated signaling pathway modulation within the colorectal cancer microenvironment

BACKGROUND

Stromal gene expression patterns predict patient outcomes in colorectal cancer. TRIM28 is a transcriptional co-repressor that regulates an abundance of genes through the KRAB domain family of transcription factors. We have previously shown that stromal expression of TRIM28 is a marker of disease relapse and poor survival in colorectal cancer. Here, we perform differential epithelium-stroma proteomic network analyses to characterize signaling pathways associated with TRIM28 within the tumor microenvironment.

METHODS

Reverse phase protein arrays were generated from laser capture micro-dissected carcinoma and stromal cells from fresh frozen colorectal cancer tissues. Phosphorylation and total protein levels were measured for 30 cancer-related signaling pathway endpoints. Strength and direction of associations between signaling endpoints were identified using Spearman's rank-order correlation analysis and compared to TRIM28 levels. Expression status of TRIM28 in tumor epithelium and stromal fibroblasts was assessed using IHC in formalin fixed tissue and the epithelium to stroma protein expression ratio method.

RESULTS

We found distinct proteomic networks in the epithelial and stromal compartments which were linked to expression levels of TRIM28. Low levels of TRIM28 in tumor stroma (high epithelium: stroma ratio) were found in 10 out of 19 cases. Upon proteomic network analyses, these stromal high ratio cases revealed moderate signaling pathway similarity exemplified by 76 significant Spearman correlations (ρ ≥ 0.75, p ≤ 0.01). Furthermore, low levels of stromal TRIM28 correlated with elevated MDM2 levels in tumor epithelium (p = 0.01) and COX-2 levels in tumor stroma (p = 0.002). Low TRIM28 epithelium to stroma ratios were associated with elevated levels of caspases 3 and 7 in stroma (p = 0.041 and p = 0.036) and an increased signaling pathway similarity in stromal cells with 81 significant Spearman correlations (ρ ≥ 0.75, p ≤ 0.01).

CONCLUSIONS

By dissecting TRIM28-associated pathways in stromal fibroblasts and epithelial tumor cells, we performed comprehensive proteomic analyses of molecular networks within the tumor microenvironment. We found modulation of several signaling pathways associated with TRIM28, which may be attributed to the pleiotropic properties of TRIM28 through its translational suppression of the family of KRAB domain transcription factors in tumor stromal compartments.

TRIM59 induces epithelial-to-mesenchymal transition and promotes migration and invasion by PI3K/AKT signaling pathway in medulloblastoma

Medulloblastoma is the most common malignant brain tumor in children. Despite remarkable advances over previous decades, the long-term survival of patients with medulloblastoma remains poor due to the frequent metastatic nature of this malignancy. The aim of the present study was to examine the role of tripartite motif containing 59 (TRIM59) in cell metastasis in medulloblastoma. It was initially demonstrated that TRIM59 expression was significantly increased in clinical medulloblastoma tissues compared with adjacent non-cancerous tissues and differentially expressed in a series of medulloblastoma cell lines. The knockdown of TRIM59 in D283 cells resulted in epithelial-to-mesenchymal transition (EMT), and decreased cell migratory and invasive capacities. By contrast, the overexpression of TRIM59 in Daoy cells was able to inhibit the EMT process and increase migratory and invasive capacities of the cells. Notably, the knockdown of TRIM59 was able to decrease the protein level of matrix metalloproteinase (MMP)-2 without altering the levels of MMP-9, and conversely the overexpression of TRIM59 was able to increase the protein level of MMP-2. Importantly, the downregulation of TRIM59 in D283 cells was able to inhibit the levels of phosphorylated (p)-AKT (Ser473), glycogen synthase kinase 3 β(GSK3β; Ser9) and phosphoinositide 3-kinase (PI3K) p85 (Tyr458) without altering the levels of total protein. The data from the present study suggest that TRIM59 induces epithelial-to-mesenchymal transition and promotes migration and invasion by PI3K/AKT signaling pathway in medulloblastoma. This data may provide novel insight into tumor metastasis and pave the way for the development of therapeutic strategies for the treatment of medulloblastoma in the clinic.

TRIM11, a direct target of miR-24-3p, promotes cell proliferation and inhibits apoptosis in colon cancer

TRIM11 (tripartite motif-containing protein 11) is an E3 ubiquitin ligase recently identified as an oncogene in malignant glioma and lung cancer. In the present study, we report that expression of TRIM11 was increased in colon cancer (CC) tissue relative to paired normal tissues and that higher TRIM11 levels predicted poor overall survival (OS) and disease-free survival (DFS) in CC patients. Mechanistically, we showed that miR-24-3p downregulation contributes to TRIM11 upregulation in CC. We also demonstrated that TRIM11 overexpression promotes cell proliferation and colony formation and inhibits apoptosis in CC, while knocking down TRIM11 using CRISPR/Cas9-mediated genome editing inhibited cell proliferation and induced apoptosis. Silencing TRIM11 in vivo decreased tumor growth. These findings indicate that TRIM11 facilitates CC progression by promoting cell proliferation and inhibiting apoptosis and that the novel miR-24-3p/TRIM11 axis may be a useful new target for treating patients with CC.

Elevated TRIM44 promotes intrahepatic cholangiocarcinoma progression by inducing cell EMT via MAPK signaling

Surgical results for intrahepatic cholangiocarcinoma (ICC) remain unsatisfactory due to the high rate of recurrence. Here, we investigated that the expression and roles of tripartite motif-containing protein 44 (TRIM44) in human ICCs. Firstly, TRIM44 expression was analyzed in several kinds of cancers by referring to public Oncomine database, and the expressions of TRIM44 mRNA and protein were tested in ICC and corresponding paratumorous tissues. Secondly, functions and mechanisms of TRIM44 in ICC cells were further evaluated by TRIM44 interference and cDNA transfection. Finally, the prognostic role of TRIM44 was assessed by Kaplan-Meier and Cox regression. We found that TRIM44 expression was upregulated in ICC tissues compared with corresponding paratumorous tissues, which were consistent with the results from the public cancer database. Knockdown of TRIM44 repressed the invasion and migration of ICC cells, while increased the ICC cell apoptosis. Additionally, high level of TRIM44 was shown to induce ICC cell epithelial to mesenchymal transition (EMT). Mechanistically, a high level of TRIM44 was found to activate MAPK signaling, and a MEK inhibitor, AZD6244, reversed cell EMT and apoptosis endowed by TRIM44 overexpression. Clinically, TRIM44 expression was positively associated with large tumor size (P = 0.035), lymphatic metastasis (P = 0.008) and poor tumor differentiation (P = 0.036). Importantly, patients in TRIM44high group had shorter overall survival and higher cumulative rate of recurrence than patients in TRIM44low group. Our results suggest elevated TRIM44 promotes ICC development by inducing cell EMT and apoptosis resistance, and TRIM44 is a valuable prognostic biomarker and promising therapeutic target of ICC.

TRIM8: Making the Right Decision between the Oncogene and Tumour Suppressor Role

The TRIM8/GERP protein is a member of the TRIM family defined by the presence of a common domain structure composed of a tripartite motif including a RING-finger, one or two B-box domains, and a coiled-coil motif. The TRIM8 gene maps on chromosome 10 within a region frequently found deleted and rearranged in tumours and transcribes a 3.0-kB mRNA. Its expression is mostly ubiquitously in murine and human tissues, and in epithelial and lymphoid cells, it can be induced by IFNγ. The protein spans 551 aa and is highly conserved during evolution. TRIM8 plays divergent roles in many biological processes, including important functions in inflammation and cancer through regulating various signalling pathways. In regulating cell growth, TRIM8 exerts either a tumour suppressor action, playing a prominent role in regulating p53 tumour suppressor activity, or an oncogene function, through the positive regulation of the NF-κB pathway. The molecular mechanisms underlying this dual role in human cancer will be discussed in depth in this review, and it will highlight the challenge and importance of developing novel therapeutic strategies specifically aimed at blocking the pro-oncogenic arm of the TRIM8 signalling pathway without affecting its tumour suppressive effects.

MiR-204 enhances mitochondrial apoptosis in doxorubicin-treated prostate cancer cells by targeting SIRT1/p53 pathway

Chemotherapy is important for adjuvant treatment of prostate cancer. However, some cancer cells exhibited low sensitivity to chemotherapeutic agents. We are supposed to sensitize these prostate cancer cells to chemotherapeutic agents such as doxorubicin. Previous reports have suggested that microRNAs (miRNAs) regulate chemosensitivity in various cancers. In the present study, we observed that expression level of miR-204 was decreased in prostate cancer cell lines and patients’ tumors. Furthermore, we found that restore of miR-204 dramatically enhanced the cytotoxicity of doxorubicin (DOX) against prostate cancer cell lines C4-2 and LNCaP carrying wild type (WT) p53. Mechanically, miR-204 in prostate cancer cells targets SIRT1 which is a histone deacetylase, and thus decreasing deacetylation of p53. As the results, acetylated p53 induced by DOX upregulates the expression of Noxa and Puma followed by induction of mitochondrial apoptosis. These data demonstrate that restore of miR-204 in prostate cancer cells enhances the mitochondrial apoptosis induced by doxorubicin by targeting the SIRT1/p53 pathway.

Knockdown of tripartite motif-59 inhibits the malignant processes in human colorectal cancer cells

The aim of the present study was to clarify the clinical implication and functional role of tripartite motif-59 (TRIM59) in colorectal carcinoma (CRC) and explore the underlying mechanism of aberrant high expression of TRIM59 in cancer. We validated that TRIM59 was upregulated in CRC samples, and also demonstrated that its upregulation was associated with advanced tumor stage of CRC patients; and its high expression indicated shorter overall survival and faster recurrence. Knockdown of TRIM59 significantly inhibited cell proliferation, migration and invasion. Cell cycle analysis showed that TRIM59-depleted cells accumulated in S-phase. In addition, the cell cycle regulators CDC25C, cyclin B1 and cyclin D1 were decreased by TRIM59 siRNA mediated knockdown. Furthermore, the depletion of TRIM59 promoted apoptosis in cell culture as indicated by the cleavage of caspase-3 and PARP when TRIM59 was depleted. These results suggested that TRIM59 is upregulated in human colorectal tumors compared with non-tumor tissues. The level of TRIM59 is correlated with malignant features of CRC and may serve as potential therapeutic and preventive strategies for CRC.

Census and evaluation of p53 target genes

The tumor suppressor p53 functions primarily as a transcription factor. Mutation of the TP53 gene alters its response pathway, and is central to the development of many cancers. The discovery of a large number of p53 target genes, which confer p53's tumor suppressor function, has led to increasingly complex models of p53 function. Recent meta-analysis approaches, however, are simplifying our understanding of how p53 functions as a transcription factor. In the survey presented here, a total set of 3661 direct p53 target genes is identified that comprise 3509 potential targets from 13 high-throughput studies, and 346 target genes from individual gene analyses. Comparison of the p53 target genes reported in individual studies with those identified in 13 high-throughput studies reveals limited consistency. Here, p53 target genes have been evaluated based on the meta-analysis data, and the results show that high-confidence p53 target genes are involved in multiple cellular responses, including cell cycle arrest, DNA repair, apoptosis, metabolism, autophagy, mRNA translation and feedback mechanisms. However, many p53 target genes are identified only in a small number of studies and have a higher likelihood of being false positives. While numerous mechanisms have been proposed for mediating gene regulation in response to p53, recent advances in our understanding of p53 function show that p53 itself is solely an activator of transcription, and gene downregulation by p53 is indirect and requires p21. Taking into account the function of p53 as an activator of transcription, recent results point to an unsophisticated means of regulation.

MDM2/X inhibitors under clinical evaluation: perspectives for the management of hematological malignancies and pediatric cancer

The two murine double minute (MDM) family members MDM2 and MDMX are at the center of an intense clinical assessment as molecular target for the management of cancer. Indeed, the two proteins act as regulators of P53, a well-known key controller of the cell cycle regulation and cell proliferation that, when altered, plays a direct role on cancer development and progression. Several evidence demonstrated that functional aberrations of P53 in tumors are in most cases the consequence of alterations on the MDM2 and MDMX regulatory proteins, in particular in patients with hematological malignancies where TP53 shows a relatively low frequency of mutation while MDM2 and MDMX are frequently found amplified/overexpressed. The pharmacological targeting of these two P53-regulators in order to restore or increase P53 expression and activity represents therefore a strategy for cancer therapy. From the discovery of the Nutlins in 2004, several compounds have been developed and reported with the ability of targeting the P53-MDM2/X axis by inhibiting MDM2 and/or MDMX. From natural compounds up to small molecules and stapled peptides, these MDM2/X pharmacological inhibitors have been extensively studied, revealing different biological features and different rate of efficacy when tested in in vitro and in vivo experimental tumor models. The data/evidence coming from the preclinical experimentation have allowed the identification of the most promising molecules and the setting of clinical studies for their evaluation as monotherapy or in therapeutic combination with conventional chemotherapy or with innovative therapeutic protocols in different tumor settings. Preliminary results have been recently published reporting data about safety, tolerability, potential side effects, and efficacy of such therapeutic approaches. In this light, the aim of this review is to give an updated overview about the state of the art of the clinical evaluation of MDM2/X inhibitor compounds with a special attention to hematological malignancies and to the potential for the management of pediatric cancers.

β2-AR activation induces chemoresistance by modulating p53 acetylation through upregulating Sirt1 in cervical cancer cells

It has been suggested that β2‐adrenergic receptor (β2‐AR)‐mediated signaling induced by catecholamines regulates the degradation of p53. However, the underlying molecular mechanisms were not known. In the present study, we demonstrated that catecholamines upregulated the expression of silent information regulator 1 (Sirt1) through activating β2‐AR‐mediated signaling pathway, since selective β2‐AR antagonist ICI 118, 551 and non‐selective β‐blocker proprenolol effectively repressed isoproterenol (ISO)‐induced Sirt1 expression. Catecholamines inhibited doxorubicin (DOX)‐induced p53 acetylation and transcription‐activation activities by inducing the expression of Sirt1. Knockdown of the Sirt1 expression by the specific siRNA remarkably blocked the inhibitory effects of ISO on DOX‐induced p53 acetylation. In addition, we demonstrated that catecholamines induced resistance of cervical cancer cells to chemotherapeutics both in vitro and in vivo and that β2‐AR was overexpressed in cervical cancer tissues. Our data suggest that the p53‐dependent, chemotherapeutics‐induced cytotoxicity in cervical cancer cells may be compromised by catecholamines‐induced upregulation of the Sirt1 expression through activating the β2‐AR signaling.

TRIM52 inhibits Japanese Encephalitis Virus replication by degrading the viral NS2A

The members of tripartite-motif containing (TRIM) protein participate in various cellular processes and play an important role in host antiviral function. TRIM proteins exert their antiviral activity either directly by degrading viral proteins through their E3 ligase activity, or indirectly by promoting host innate immunity. This study demonstrated for the first time that TRIM52 is a novel antiviral TRIM protein against Japanese encephalitis virus (JEV) infection. Overexpression of TRIM52 restricted JEV replication in BHK-21 and 293T cells. In addition, JEV nonstructural protein 2A (NS2A) is a protein that interacts with TRIM52. Their interaction degraded NS2A in a proteasome-dependent manner via the E3 ligase activity of TRIM52. Thus, TRIM52 is a novel antiviral TRIM protein, and it exerted antiviral activity against JEV infection by targeting and degrading viral NS2A.

The implication of SUMO in intrinsic and innate immunity

Since its discovery, SUMOylation has emerged as a key post-translational modification involved in the regulation of host-virus interactions. SUMOylation has been associated with the replication of a large number of viruses, either through the direct modification of viral proteins or through the modulation of cellular proteins implicated in antiviral defense. SUMO can affect protein function via covalent or non-covalent binding. There is growing evidence that SUMO regulates several host proteins involved in intrinsic and innate immunity, thereby contributing to the process governing interferon production during viral infection; as well as the interferon-activated Jak/STAT pathway. Unlike the interferon-mediated innate immune response, intrinsic antiviral resistance is mediated by constitutively expressed antiviral proteins (defined as restriction factors), which confer direct viral resistance through a variety of mechanisms. The aim of this review is to evaluate the role of SUMO in intrinsic and innate immunity; highlighting the involvement of the TRIM family proteins, with a specific focus on the mechanism through which SUMO affects i- interferon production upon viral infection, ii-interferon Jak/STAT signaling and biological responses, iii-the relationship between restriction factors and RNA viruses.