Tripartite motif containing 28 (TRIM28) promotes breast cancer metastasis by stabilizing TWIST1 protein

Ailanthone Restrains Osteosarcoma Growth and Metastasis by Decreasing the Expression of Regulator of G Protein Signaling 4 and Twist Family BHLH Transcription Factor 1

Traditional Chinese medicine Ailanthone (AIL) has been confirmed to possess antimalarial, anti-inflammatory, and anticancer effects. Here, this study aimed to excavate the biological role and mechanism of AIL on osteosarcoma (OS) progression. Levels of Regulator of G protein signaling 4 (RGS4) and Twist Family BHLH Transcription Factor 1 (TWIST1) were detected by qRT-PCR and western blotting. In vitro and tumor formation experiments were conducted for functional analysis. The protein interaction between RGS4 and TWIST1 was verified by using a Co-immunoprecipitation assay. AIL impeded the proliferation, invasion, migration, and epithelial-mesenchymal transition (EMT) progression, but induced apoptosis in OS cells. RGS4 was highly expressed in OS tissues and cells and was decreased by AIL in cells. RGS4 silencing suppressed the growth and metastasis of OS cells, and RGS4 overexpression reversed the anticancer action of AIL in OS cells. Mechanistically, RGS4 interacted with TWIST1 and positively regulated its expression. TWIST1 was highly expressed in OS tissues and cells and could be reduced by AIL in cells. Moreover, TWIST1 overexpression abolished RGS4 silencing-triggered growth and metastasis inhibition in OS cells. Importantly, AIL impeded OS growth and metastasis in vivo by regulating RGS4 and TWIST1. Ailanthone restrained OS growth and metastasis by decreasing RGS4 and TWIST1 expression.

TRIM25: A Global Player of Cell Death Pathways and Promising Target of Tumor-Sensitizing Therapies

Therapy resistance still constitutes a common hurdle in the treatment of many human cancers and is a major reason for treatment failure and patient relapse, concomitantly with a dismal prognosis. In addition to "intrinsic resistance", e.g., acquired by random mutations, cancer cells typically escape from certain treatments ("acquired resistance") by a large variety of means, including suppression of apoptosis and other cell death pathways via upregulation of anti-apoptotic factors or through inhibition of tumor-suppressive proteins. Therefore, ideally, the tumor-cell-restricted induction of apoptosis is still considered a promising avenue for the development of novel, tumor (re)sensitizing therapies. A growing body of evidence has highlighted the multifaceted role of tripartite motif 25 (TRIM25) in controlling different aspects of tumorigenesis, including chemotherapeutic drug resistance. Accordingly, overexpression of TRIM25 is observed in many tumors and frequently correlates with a poor patient survival. In addition to its originally described function in antiviral innate immune response, TRIM25 can play critical yet context-dependent roles in apoptotic- and non-apoptotic-regulated cell death pathways, including pyroposis, necroptosis, ferroptosis, and autophagy. The review summarizes current knowledge of molecular mechanisms by which TRIM25 can interfere with different cell death modalities and thereby affect the success of currently used chemotherapeutics. A better understanding of the complex repertoire of cell death modulatory effects by TRIM25 is an essential prerequisite for validating TRIM25 as a potential target for future anticancer therapy to surmount the high failure rate of currently used chemotherapies.

Coagulation factor II thrombin receptor as a promising biomarker in breast cancer management

This study aims to comprehensively investigate the role of coagulation factor II thrombin receptor (F2R) in breast cancer (BC) and to evaluate its potential as a biomarker in this context. Data on female BC were retrieved from the TCGA database. Comparative analyses were performed, including enrichment analysis, tumor immune microenvironment analysis, drug sensitivity testing, molecular docking, and cell-based experiments, to assess the expression and function of F2R in BC. Statistical analyses and graphical representations were conducted using R software. The study confirmed a significant upregulation of F2R in BC, which was associated with a more favorable prognosis. Clinical correlation analysis revealed a strong association between F2R expression and key clinical parameters, such as estrogen receptor and progesterone receptor status. Additionally, genes co-expressed with F2R were significantly linked to various biological processes, including cell cycle regulation, oxidative phosphorylation, ribosomal function, and extracellular matrix interactions. F2R also showed associations with immune modulators, particularly CD200 and NRP1. Drug sensitivity analysis, molecular docking, and cell experiments consistently demonstrated positive correlations between F2R expression and sensitivity to dasatinib. This study underscores the potential of F2R as a valuable biomarker in BC, providing insights into the molecular mechanisms underlying tumorigenesis.

XAF1 antagonizes TRIM28 activity through the assembly of a ZNF313-mediated destruction complex to suppress tumor malignancy

X-linked inhibitor of apoptosis-associated factor 1 (XAF1) is a stress-inducible pro-apoptotic protein that is commonly inactivated in multiple human cancers. Nevertheless, the molecular basis for its tumor suppression function remains largely uncharacterized. Here we report that XAF1 antagonizes the oncogenic activity of tripartite motif containing 28 (TRIM28) ubiquitin E3 ligase through zinc finger protein 313 (ZNF313)-induced ubiquitination and proteasomal degradation. XAF1 exerts apoptosis-promoting effect more strongly in TRIM28+/+ versus XAF1-/- tumor cells and suppresses tumor cell growth, migration, invasion, and epithelial-to-mesenchymal transition and xenograft tumor growth in a highly TRIM28-dependent fashion. Mechanistically, XAF1 interacts directly with the RING domains of TRIM28 and ZNF313 through the ZF6 and ZF7 domain, respectively, thereby facilitating ZNF313 interaction with and ubiquitination of TRIM28. A mutant XAF1 lacking either ZF6 or ZF7 domain exhibits no activity to promote TRIM28 ubiquitination. By destabilizing TRIM28, XAF1 blocks TRIM28-driven ubiquitination of p53 and RLIM, p53-HDAC1 interaction, and TWIST1 stabilization. Intriguingly, TRIM28 destabilizes XAF1 through K48-linked polyubiquitination and proteasomal degradation to protect tumor cells from apoptotic stress, indicating its role as an intrinsic antagonist against XAF1 and the antagonistic interplay of XAF1 and TRIM28. XAF1 expression is inversely correlated with TRIM28 expression in cancer cell lines and tumor tissues and more tightly associated with the survival of TRIM28-high versus TRIM28-low patients. Together, this study uncovers a novel mechanism by which XAF1 suppresses tumor malignancy and an important role for XAF1-TRIM28 interplay in governing stress response, illuminating the mechanistic consequence of its alteration during tumorigenic process.

ERα Coregulator TRIM28 Promotes Breast Cancer Progression by Activating the AKT/GSK3β Pathway

Estrogen receptor α (ERα) promotes the growth and survival of ER-positive breast cancer (BC) cells. ER regulates ER expression target genes by directly binding to specific estrogen response elements, upon activation by estrogens. In this study, 106 proteins interacting with endogenous chromatin-bound ER in a BC cell line MCF7 were identified using the RIME method. The interactome data showed that the tripartite motif containing 28 (TRIM28) is the most significantly enriched ER-associated protein. This study provides evidence that TRIM28 expression improves ER transcriptional activity and promotes the BC cells proliferation, migration, and invasion of BC cells. The high expression of TRIM28 is associated with poor clinical outcomes in patients with ER-positive BC. Mechanistic experiments indicate that TRIM28 expression activates the AKT/GSK3β pathway. To conclude, TRIM28 acts as a regulatory protein of ER and AKT signaling; therefore, it can be a target for the therapeutic interventions of BC.

Multifaceted role of TRIM28 in health and disease

The TRIM (tripartite motif) family, with TRIM28 as a key member, plays a vital role in regulating health and disease. TRIM28 contains various functional domains essential for transcriptional regulation, primarily through its interaction with KRAB-ZNF proteins, which influence chromatin remodeling and gene expression. Despite extensive research, the precise mechanisms by which TRIM28 impacts health and disease remain elusive. This review delves into TRIM28's multifaceted roles in maintaining health, contributing to a variety of diseases, and influencing cancer progression. In cancers, TRIM28 exhibits a dual nature, functioning as both a tumor promoter and suppressor depending on the cellular context and cancer type. The review also explores its critical involvement in processes such as DNA repair, cell cycle regulation, epithelial-to-mesenchymal transition, and the maintenance of stem cell properties. By uncovering TRIM28's complex roles across different cancers and other diseases, this review underscores its potential as a therapeutic target. The significance of TRIM28 as a versatile regulator opens the door to innovative therapeutic strategies, particularly in cancer treatment and the management of other diseases. Ongoing research into TRIM28 may yield key insights into disease progression and novel treatment options.

TRIM28 promotes tumor growth and metastasis in breast cancer by targeting the BRD7 protein for ubiquitination and degradation

PURPOSE

Bromodomain-containing protein 7 (BRD7) is downregulated and functions as a tumor suppressor in many types of cancers including breast cancer, and the dysregulation of BRD7 expression is closely related to the development and progression of breast cancer. Whereas little attention has been focused on the regulation of BRD7 protein levels in breast cancer, which needs to be further elucidated.

METHODS

The protein stability of BRD7 in breast cancer cells and BRD7 protein level in breast cancer tissues was examined by Western Blotting. The potential E3 ubiquitin ligase proteins that interact with the BRD7 was screened by coimmunoprecipitation combined with mass spectrometry analysis in MDA-MB-231 cells. We proved the interaction between BRD7 and tripartite motif containing 28 (TRIM28) through Co-Immunoprecipitation (Co-IP) and immunofluorescence assays. Co-IP and ubiquitination assay were used to explore the specific binding domain between BRD7 and TRIM28 and the ubiquitination site of BRD7. The effects of TRIM28 on the BRD7 protein stability and ubiquitination level was investigated by qPCR, Western Blot and Co-IP assay. CCK-8 and clone formation assays were carried out to assess the effect of TRIM28 on proliferation ability of breast cancer ells. Transwell assay and wound healing assay were used to investigate the effect of TRIM28 on breast cancer cell invasion and migration. Flow cytometry was used to detect the effect of TRIM28 on cell cycle and apoptosis of breast cancer cells. In addition, we confirmed effect of TRIM28 on tumor growth and metastasis by xenograft and metastatic mouse models. We designed some recovery assays to explore the role of recovery BRD7 in TRIM28-mediated promotion of malignant progression of breast cancer in vivo and in vitro. Finally, the clinical significance of TRIM28 and BRD7 was proved by immunohistochemistry.

RESULTS

In this study, we demonstrated that BRD7 was an unstable protein and might be regulated by ubiquitination in breast cancer; furthermore, we found that the Coiled-Coil region of TRIM28 could directly bind to N-terminal of BRD7, and TRIM28 mediates BRD7 ubiquitination and degradation dependent on K21 by acting as a potential E3 ubiquitin ligase. Moreover, TRIM28 promoted cell proliferation, migration, invasion, xenograft tumor growth and metastasis, thus playing an oncogenic role in breast cancer. Furthermore, the restoration of BRD7 expression in breast cancer significantly reversed the promotional effects of TRIM28 on malignant progression both in vitro and in vivo. In addition, TRIM28 was highly expressed in the biopsy tissues of breast cancer, and its expression was negatively correlated with BRD7 expression and positively correlated with TNM stage and poor prognosis of BC patients.

CONCLUSIONS

Our findings provide a novel mechanism by which TRIM28 significantly facilitates BRD7 ubiquitination and degradation, thus promoting breast cancer malignant progression. Targeting the TRIM28/BRD7 axis might be a novel potential strategy for the clinical diagnosis and treatment of breast cancer.

The tripartite motif-containing 24 is a multifunctional player in human cancer

Tripartite motif-containing 24 (TRIM24), also known as transcriptional intermediary factor 1α (TIF1α), is the founding member of TIF1 family. Recent evidence indicates that aberrant expression of TRIM24, functions as an oncogene, is associated with poor prognosis across various cancer types. TRIM24 exhibits a multifaceted structure comprising an N-terminal TRIM region with a RING domain, B-box type 1 and type 2 domains, and a coiled-coil region, as well as a C-terminal plant-homeodomain (PHD)-bromodomain. The bromodomain serves as a 'reader' of epigenetic histone marks, regulating chromatin structure and gene expression by linking associated proteins to acetylated nucleosomal targets, thereby controlling transcription of genes. Notably, bromodomains have emerged as compelling targets for cancer therapeutic development. In addition, TRIM24 plays specialized roles as a signal transduction molecule, orchestrating various cellular signaling cascades in cancer cells. Herein, we review the recent advancements in understanding the functions of TRIM24, and demonstrate the research progress in utilizing TRIM24 as a target for cancer therapy.

TRIM28 in cancer and cancer therapy

TRIM28 (tripartite motif protein 28) was initially believed to be a transcription inhibitor that plays an important role in DNA damage repair (DDR) and in maintaining cancer cellular stemness. As research has continued to deepen, several studies have found that TRIM28 not only has ubiquitin E3 ligase activity to promote degradation of substrates, but also can promote SUMOylation of substrates. Although TRIM28 is highly expressed in various cancer tissues and has oncogenic effects, there are still a few studies indicating that TRIM28 has certain anticancer effects. Additionally, TRIM28 is subject to complex upstream regulation. In this review, we have elaborated on the structure and regulation of TRIM28. At the same time, highlighting the functional role of TRIM28 in tumor development and emphasizing its impact on cancer treatment provides a new direction for future clinical antitumor treatment.

Emerging roles of tripartite motif family proteins (TRIMs) in breast cancer

Breast cancer (BC) is the most common malignant tumor worldwide. Despite enormous progress made in the past decades, the underlying mechanisms of BC remain further illustrated. Recently, TRIM family proteins proved to be engaged in BC progression through regulating various aspects. Here we reviewed the structures and basic functions of TRIM family members and first classified them into three groups according to canonical polyubiquitination forms that they could mediate: K48- only, K63- only, and both K48- and K63-linked ubiquitination. Afterwards, we focused on the specific biological functions and mechanisms of TRIMs in BCs, including tumorigenesis and invasiveness, drug sensitivity, tumor immune microenvironment (TIME), cell cycle, and metabolic reprogramming. We also explored the potential of TRIMs as novel biomarkers for predicting prognosis and future therapeutic targets in BC.

Tripartite motif-containing 28 (TRIM28) expression and cordycepin inhibition in progression, prognosis, and therapeutics of patients with breast invasive carcinoma

Breast cancer (BC) is the most common tumor in women worldwide. TRIM28 (RNF96) plays pleiotropic biological functions, such as silencing target genes, facilitating DNA repair, stimulating cellular proliferation and differentiation, and contributing to cancer progression. TRIM28 plays an increasingly crucial role in cancer, but its impact on BC, including breast invasive carcinoma, remains poorly understood. In the current study, analyses of online databases, quantitative real-time quantitative PCR, immunohistochemistry, and western blotting were performed on patients with breast invasive carcinoma (BRCA). Cordycepin (CD) was used to monitor BC progression and TRIM28 expression in vivo. As a result, we observed that TRIM28 is highly expressed in breast invasive carcinoma tissues compared with the corresponding normal tissues and is correlated with metastatic / invasive progression. High expression of TRIM28 might serve as a prognostic marker for long-term survival in triple-negative BC, advanced BC, or breast invasive carcinoma. Although TRIM28 methylation in tumor tissues of breast invasive carcinoma is not significantly changed compared to the matched normal tissues, the expressions and methylation of TRIM28 are significantly reversely correlated. TRIM28 expression was inhibited by CD in the mouse model, indicating its role in preventing BC progression. Thus, TRIM28 might be a potentially valuable molecular target for forecasting the progression / prognosis of patients with breast invasive carcinoma. CD, which represses BC growth/metastasis, may be involved partially through suppressing TRIM28 expression.

Macrophage-Related Gene Signatures for Predicting Prognosis and Immunotherapy of Lung Adenocarcinoma by Machine Learning and Bioinformatics

Background

In recent years, the immunotherapy of lung adenocarcinoma has developed rapidly, but the good therapeutic effect only exists in some patients, and most of the current predictors cannot predict it very well. Tumor-infiltrating macrophages have been reported to play a crucial role in lung adenocarcinoma (LUAD). Thus, we want to build novel molecular markers based on macrophages.

Methods

By non-negative matrix factorization (NMF) algorithm and Cox regression analysis, we constructed macrophage-related subtypes of LUAD patients and built a novel gene signature consisting of 12 differentially expressed genes between two subtypes. The gene signature was further validated in Gene-Expression Omnibus (GEO) datasets. Its predictive effect on prognosis and immunotherapy outcome was further evaluated with rounded analyses. We finally explore the role of TRIM28 in LUAD with a series of in vitro experiments.

Results

Our research indicated that a higher LMS score was significantly correlated with tumor staging, pathological grade, tumor node metastasis stage, and survival. LMS was identified as an independent risk factor for OS in LUAD patients and verified in GEO datasets. Clinical response to immunotherapy was better in patients with low LMS score compared to those with high LMS score. TRIM28, a key gene in the gene signature, was shown to promote the proliferation, invasion and migration of LUAD cell.

Conclusion

Our study highlights the significant role of gene signature in predicting the prognosis and immunotherapy efficacy of LUAD patients, and identifies TRIM28 as a potential biomarker for the treatment of LUAD.

Intricate confrontation: Research progress and application potential of TRIM family proteins in tumor immune escape

BACKGROUND

Tripartite motif (TRIM) family proteins have more than 80 members and are widely found in various eukaryotic cells. Most TRIM family proteins participate in the ubiquitin-proteasome degradation system as E3-ubiquitin ligases; therefore, they play pivotal regulatory roles in the occurrence and development of tumors, including tumor immune escape. Due to the diversity of functional domains of TRIM family proteins, they can extensively participate in multiple signaling pathways of tumor immune escape through different substrates. In current research and clinical contexts, immune escape has become an urgent problem. The extensive participation of TRIM family proteins in curing tumors or preventing postoperative recurrence and metastasis makes them promising targets.

AIM OF REVIEW

The aim of the review is to make up for the gap in the current research on TRIM family proteins and tumor immune escape and propose future development directions according to the current progress and problems.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This up-to-date review summarizes the characteristics and biological functions of TRIM family proteins, discusses the mechanisms of TRIM family proteins involved in tumor immune escape, and highlights the specific mechanism from the level of structure-function-molecule-pathway-phenotype, including mechanisms at the level of protein domains and functions, at the level of molecules and signaling pathways, and at the level of cells and microenvironments. We also discuss the application potential of TRIM family proteins in tumor immunotherapy, such as possible treatment strategies for combination targeting TRIM family protein drugs and checkpoint inhibitors for improving cancer treatment.

The SUMOylation and ubiquitination crosstalk in cancer

BACKGROUND

The cancer occurrence and progression are largely affected by the post-translational modifications (PTMs) of proteins. Currently, it has been shown that the relationship between ubiquitination and SUMOylation is highly complex and interactive. SUMOylation affects the process of ubiquitination and degradation of substrates. Contrarily, SUMOylation-related proteins are also regulated by the ubiquitination process thus altering their protein levels or activity. Emerging evidence suggests that the abnormal regulation between this crosstalk may lead to tumorigenesis.

PURPOSE

In this review, we have discussed the study of the relationship between ubiquitination and SUMOylation, as well as the possibility of a corresponding application in tumor therapy.

METHODS

The relevant literatures from PubMed have been reviewed for this article.

CONCLUSION

The interaction between ubiquitination and SUMOylation is crucial for the occurrence and development of cancer. A greater understanding of the crosstalk of SUMOylation and ubiquitination may be more conducive to the development of more selective and effective SUMOylation inhibitors, as well as a promotion of synergy with other tumor treatment strategies.

Overexpression of TRIM28 predicts an unfavorable prognosis and promotes the proliferation and migration of hepatocellular carcinoma

Objectives

Previous studies have shown that tripartite motif-containing 28 (TRIM28) might be a latent target for cancer therapy. However, the detailed roles and mechanisms of TRIM28 in hepatocellular carcinoma (HCC) remain ambiguous.

Methods

We systematically analyzed TRIM28 mRNA expression and protein levels in HCC tissues based on large-scale data and publicly available immunohistochemistry images. We estimated the prognostic capacity of TRIM28 in HCC. Additionally, we performed gene enrichment, immune infiltration, and drug sensitivity analyses to further explore the roles of TRIM28 in HCC. To determine the effect of TRIM28 expression on HCC cell proliferation and migration, successful transfection of siRNAs was conducted in MHCC97-L and Huh7 cells, followed by cell functional assays.

Results

We verified the overexpression of TRIM28 in HCC at the mRNA and protein levels. The summary receiver operating characteristics curve with the area under curve of 0.84 (95 % CI: 0.81–0.87) indicated the high accuracy of increasing TRIM28 expression for discriminating HCC from non-HCC tissues. According to The Cancer Genome Atlas datasets, TRIM28 mRNA expression was significantly related to age, grade, stage, and pathologic T (p<0.05). Increased TRIM28 expression levels were significant correlated to poor survival in HCC patients. An enrichment analysis suggested that TRIM28-reated genes primarily participated in the spliceosome signaling pathway, with hub genes including SNRPA1, SNRPF, SNRPD1, SF3B2, SNRPB, SNRPE, and EFTUD2. TRIM28 expression was correlated with the infiltration of five immune cells. Higher TRIM28 expression was linked to better sensitivity of tumor cells to pluripotin. Molecular docking showed that pluripotin could bind to TRIM28. Further, knockdown of TRIM28 inhibited the proliferation and migration of HCC cells.

Conclusions

TRIM28 is highly expressed in HCC and contribute to the proliferation and migration of HCC cells, leading to unfavorable outcomes. These findings indicate TRIM28 promise as a novel prognostic indicator.

Impact of BSG/CD147 gene expression on diagnostic, prognostic and therapeutic strategies towards malignant cancers and possible susceptibility to SARS-CoV-2

BACKGROUND

BSG (CD147) is a member of the immunoglobulin superfamily that shows roles for potential prognostics and therapeutics for metastatic cancers and SARS-CoV-2 invasion for COVID-19. The susceptibility of malignant cancers to SARS-CoV-2 as well as the correlations between disease outcome and BSG expression in tumor tissues have not been studied in depth.

METHODS

In this study, we explored the BSG expression profile, survival correlation, DNA methylation, mutation, diagnostics, prognostics, and tumor-infiltrating lymphocytes (TILs) from different types of cancer tissues with corresponding healthy tissues. In vitro studies for cordycepin (CD), N6-(2-hydroxyethyl) adenosine (HEA), N6, N6-dimethyladenosine (m⁶₂A) and 5'-uridylic acid (UMP) on BSG expression were also conducted.

RESULTS

We revealed that BSG is conserved among different species, and significantly upregulated in seven tumor types, including ACC, ESCA, KICH, LIHC, PAAD, SKCM and THYM, compared with matched normal tissues, highlighting the susceptibility of these cancer patients to SARS-CoV-2 invasion, COVID-19 severity and progression of malignant cancers. High expression in BSG was significantly correlated with a short OS in LGG, LIHC and OV patients, but a long OS in KIRP patients. Methylation statuses in the BSG promoter were significantly higher in BRCA, HNSC, KIRC, KIRP, LUSC, PAAD, and PRAD tumor tissues, but lower in READ. Four CpGs in the BSG genome were identified as potential DNA methylation biomarkers which could be used to predict malignant cancers from normal individuals. Furthermore, a total of 65 mutation types were found, in which SARC showed the highest mutation frequency (7.84%) and THYM the lowest (0.2%). Surprisingly, both for disease-free and progression-free survival in pan-cancers were significantly reduced after BSG mutations. Additionally, a correlation between BSG expression and immune lymphocytes of CD56bright natural killer cell, CD56dim natural killer cell and monocytes, MHC molecules of HLA-A, HLA-B, HLA-C and TAPBP, immunoinhibitor of PVR, PVRL2, and immunostimulators of TNFRSF14, TNFRSF18, TNFRSF25, and TNFSF9, was revealed in most cancer types. Moreover, BSG expression was downregulated by CD, HEA, m⁶₂A or UMP in cancer cell lines, suggesting therapeutic potentials for interfering entry of SARS-CoV-2.

CONCLUSIONS

Altogether, our study highlights the values of targeting BSG for diagnostic, prognostic and therapeutic strategies to fight malignant cancers and COVID-19. Small molecules CD, HEA, m⁶₂A and UMP imply therapeutic potentials in interfering with entry of SARS-CoV-2 and progression of malignant cancers.

KAP1 modulates osteogenic differentiation via the ERK/Runx2 cascade in vascular smooth muscle cells

BACKGROUND

Osteoblast phenotypic transition in vascular smooth muscle cells (VSMCs) has been unveiled as a common cause of vascular calcification (VC). Krüppel-Associated Box (KRAB)-Associated Protein 1(KAP1) is a transcriptional corepressor that modulates various intracellular pathological processes from gene expression to DNA repair to signal transduction. However, the function and mechanism of KAP1 on the osteoblastic differentiation of VSMCs have not been evaluated yet.

METHODS AND RESULTS

We demonstrate that the expression of KAP1 in VSMCs is significantly enhanced in vivo and in vitro calcification models. Downregulating the expression of KAP1 suppresses the osteoblast phenotypic transition of VSMCs, which is indicated by a decrease in the expression of osteoblast marker collagenase type I (COL I) and an increase in the expression of VSMC marker α-smooth muscle actin (α-SMA). Conversely, exogenous overexpression of KAP1 could promote osteoblast phenotypic transition of VSMCs. Moreover, KAP1 upregulated the expression of RUNX family transcription factor 2 (Runx2), an inducer of osteoblast that positively regulates many osteoblast-related genes, such as COL I. Evaluation of the potential mechanism demonstrated that KAP1 promoted osteoblast phenotypic transition of VSMCs by activating the extracellular regulated protein kinases (ERK) signaling pathway, which could activate Runx2. In support of this finding, KAP1-induced cell osteoblast phenotypic transition is abolished by treatment with PD0325901, a specific ERK inhibitor.

CONCLUSIONS

The present study suggested that KAP1 participated in the osteoblast differentiation of VSMCs via the ERK/Runx2 cascade and served as a potential diagnostics and therapeutics target for vascular calcification.

The role of tripartite motif-containing 28 in cancer progression and its therapeutic potentials

Tripartite motif-containing 28 (TRIM28) belongs to tripartite motif (TRIM) family. TRIM28 not only binds and degrades its downstream target, but also acts as a transcription co-factor to inhibit gene expression. More and more studies have shown that TRIM28 plays a vital role in tumor genesis and progression. Here, we reviewed the role of TRIM28 in tumor proliferation, migration, invasion and cell death. Moreover, we also summarized the important role of TRIM28 in tumor stemness sustainability and immune regulation. Because of the importance of TRIM28 in tumors, TIRM28 may be a candidate target for anti-tumor therapy and play an important role in tumor diagnosis and treatment in the future.

Altered Expression of TRIM Proteins - Inimical Outcome and Inimitable Oncogenic Function in Breast Cancer with Diverse Carcinogenic Hallmarks

Deregulation of ubiquitin-mediated degradation of oncogene products or tumor suppressors appears to be implicated in the genesis of carcinomas, according to new clinical findings. Conferring to recent research, some members of the tripartite motif (TRIM) proteins (a subfamily of the RING type E3 ubiquitin ligases) act as significant carcinogenesis regulators. Intracellular signaling, development, apoptosis, protein quality control, innate immunity, autophagy, and carcinogenesis are all regulated by TRIM family proteins, the majority of which have E3 ubiquitin ligase activity. The expression of TRIMs in tumors is likely to be related to the formation and/or progression of the disease, and TRIM expression could be used to predict cancer prognosis. Breast cancer is the most common malignancy in women and also the leading cause of death. TRIM family proteins have unique, vital activities, and their dysregulation, such as TRIM 21, promotes breast cancer, according to growing evidence. Many TRIM proteins have been identified as important cancer biomarkers, with decreased or elevated levels of expression. TRIM29 functions as a hypoxia-induced tumor suppressor gene, revealing a new molecular mechanism for ATM-dependent breast cancer suppression. In breast cancer cells, the TRIM28-TWIST1-EMT axis exists, and TRIM28 enhances breast cancer metastasis by stabilizing TWIST1, and thereby increasing epithelial-tomesenchymal transition. Interestingly, many TRIM proteins are involved in the control of p53, and many TRIM proteins are likewise regulated by p53, according to current research. Furthermore, TRIMs linked to specific tumors may aid in the creation of innovative TRIM-targeted cancer treatments. This review focuses on TRIM proteins that are involved in tumor development, progression, and are of clinical significance in breast cancer.

The speckle-type POZ protein (SPOP) inhibits breast cancer malignancy by destabilizing TWIST1

Epithelial-mesenchymal transition (EMT) inducing transcription factor TWIST1 plays a vital role in cancer metastasis. How the tumor-suppressive E3 ligase, speckle-type POZ protein (SPOP), regulates TWIST1 in breast cancer remains unknown. In this study, we report that SPOP physically interacts with, ubiquitinates, and destabilizes TWIST1. SPOP promotes K63-and K48-linked ubiquitination of TWIST1, predominantly at K73, thereby suppressing cancer cell migration and invasion. Silencing SPOP significantly enhances EMT, which accelerates breast cancer cell migration and invasiveness in vitro and lung metastasis in vivo. Clinically, SPOP is negatively correlated with the levels of TWIST1 in highly invasive breast carcinomas. Reduced SPOP expression, along with elevated TWIST1 levels, is associated with poor prognosis in advanced breast cancer patients, particularly those with metastatic triple-negative breast cancer (TNBC). Taken together, we have disclosed a new mechanism linking SPOP to TWIST1 degradation. Thus SPOP may serve as a prognostic marker and a potential therapeutic target for advanced TNBC patients.

TRIM33 drives prostate tumor growth by stabilizing androgen receptor from Skp2-mediated degradation

Androgen receptor (AR) is a master transcription factor that drives prostate cancer (PCa) development and progression. Alterations in the expression or activity of AR coregulators significantly impact the outcome of the disease. Using a proteomics approach, we identified the tripartite motif-containing 33 (TRIM33) as a novel transcriptional coactivator of AR. We demonstrate that TRIM33 facilitates AR chromatin binding to directly regulate a transcription program that promotes PCa progression. TRIM33 further stabilizes AR by protecting it from Skp2-mediated ubiquitination and proteasomal degradation. We also show that TRIM33 is essential for PCa tumor growth by avoiding cell-cycle arrest and apoptosis, and TRIM33 knockdown sensitizes PCa cells to AR antagonists. In clinical analyses, we find TRIM33 upregulated in multiple PCa patient cohorts. Finally, we uncover an AR-TRIM33-coactivated gene signature highly expressed in PCa tumors and predict disease recurrence. Overall, our results reveal that TRIM33 is an oncogenic AR coactivator in PCa and a potential therapeutic target for PCa treatment.

Comprehensive Analysis of the Expression and Prognosis for Tripartite Motif-Containing Genes in Breast Cancer

Tripartite motif-containing genes (TRIMs), with a ubiquitin ligase’s function, play critical roles in antitumor immunity by activating tumor-specific immune responses and stimulating tumor proliferation, thus affecting patient outcomes. However, the expression pattern and prognostic values of TRIMs in breast cancer (BC) are not well clarified. In this study, several datasets and software were integrated to perform a comprehensive analysis of the expression pattern in TRIMs and investigate their prognosis values in BC. We found that TRIM59/46 were significantly upregulated and TRIM66/52-AS1/68/7/2/9/29 were decreased in BC and validated them using an independent cohort. The expression of numerous TRIMs are significantly correlated with BC molecular subtypes, but not with tumor stages or patient age at diagnosis. Higher expression of TRIM3/14/69/45 and lower expressions of TRIM68/2 were associated with better overall survival in BC using the Kaplan–Meier analysis. The multivariate Cox proportional hazards model identified TRIM45 as an independent prognostic marker. Further analysis of single-cell RNA-seq data revealed that most TRIMs are also expressed in nontumor cells. Higher expression of some TRIMs in the immune or stromal cells suggests an important role of TRIMs in the BC microenvironment. Functional enrichment of the co-expression genes indicates that they may be involved in muscle contraction and interferon-gamma signaling pathways. In brief, through the analysis, we provided several TRIMs that may contribute to the tumor progression and TRIM45 as a potential new prognostic biomarker for BC.

The Emerging Role of E3 Ubiquitin Ligase SMURF2 in the Regulation of Transcriptional Co-Repressor KAP1 in Untransformed and Cancer Cells and Tissues

Simple Summary

KAP1 plays an essential role in different molecular and cellular processes central to carcinogenesis, disease progression, and treatment response, revealing both tumor promoting and anticancer functions. The mechanisms that control the steady-state levels of KAP1 and its protein abundance are not well known. Our findings show that SMURF2, a ubiquitously-expressed HECT-type E3 ubiquitin ligase with suggested anticancer activities, is capable to directly bind, ubiquitinate, and regulate KAP1 expression levels in non-cancerous and tumor cells and tissues. The data further show that SMURF2 has a significant influence on KAP1 interactome, regulating its protein–protein interactions and functions in a catalytically-dependent manner. These findings reveal SMURF2 as a pivotal regulator of KAP1, laying a foundation for the investigation of the role of the SMURF2–KAP1 axis in carcinogenic processes and therapeutic responses to anticancer treatment.

Abstract

KAP1 is an essential nuclear factor acting as a scaffold for protein complexes repressing transcription. KAP1 plays fundamental role in normal and cancer cell biology, affecting cell proliferation, DNA damage response, genome integrity maintenance, migration and invasion, as well as anti-viral and immune response. Despite the foregoing, the mechanisms regulating KAP1 cellular abundance are poorly understood. In this study, we identified the E3 ubiquitin ligase SMURF2 as an important regulator of KAP1. We show that SMURF2 directly interacts with KAP1 and ubiquitinates it in vitro and in the cellular environment in a catalytically-dependent manner. Interestingly, while in the examined untransformed cells, SMURF2 mostly exerted a negative impact on KAP1 expression, a phenomenon that was also monitored in certain Smurf2-ablated mouse tissues, in tumor cells SMURF2 stabilized KAP1. This stabilization relied on the unaltered E3 ubiquitin ligase function of SMURF2. Further investigations showed that SMURF2 regulates KAP1 post-translationally, interfering with its proteasomal degradation. The conducted immunohistochemical studies showed that the reciprocal relationship between the expression of SMURF2 and KAP1 also exists in human normal and breast cancer tissues and suggested that this relationship may be disrupted by the carcinogenic process. Finally, through stratifying KAP1 interactome in cells expressing either SMURF2 wild-type or its E3 ligase-dead form, we demonstrate that SMURF2 has a profound impact on KAP1 protein–protein interactions and the associated functions, adding an additional layer in the SMURF2-mediated regulation of KAP1. Cumulatively, these findings uncover SMURF2 as a novel regulator of KAP1, governing its protein expression, interactions, and functions.

Identification Prognostic Value and Correlation with Tumor-Infiltrating Immune Cells of Tripartite-Motif Family Genes in Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the most common and mortality types of malignant tumors in the world. The Tripartite-Motif (TRIM) protein family consists of more than 80 proteins with E3 ubiquitin ligase activity. Increasing studies have found that TRIM family proteins play an extremely important role in the occurrence and development of tumors. However, the expression and prognostic values of TRIMs in HCC have not been clarified.

Methods

We used bioinformatic methods to explore the potential function of TRIM family genes in the HCC. Web servers ONCOMINE, UALCAN, GEPIA, cBioPortal, STRING, DAVID 6.8 and TIMER were used in this research.

Results

We screened TRIM1-76 and found the expressions of TRIM6, TRIM11, TRIM16, TRIM18(MID1), TRIM24, TRIM28, TRIM31, TRIM37, TRIM45, TRIM52, TRIM59, TRIM66 were significantly changed in HCC. Among them, TRIM24, TRIM28, TRIM37, TRIM45 and TRIM59 had significant effects on pathological stages, overall survival and disease free survival. Functions of these genes are primarily related to transcriptional misregulation in cancer, p53 signaling pathway, alcoholism and viral carcinogenesis, FoxO signal pathway, PI3K-AKT pathway, cell cycle, microRNAs in cancer. Our results showed the significant correlation between TRIMs expression and infiltration of innate immune cells (macrophages, neutrophils, and dendritic cells).

Conclusion

Our result provides novel insights into the function of TRIM family genes, which may be used as potential references for drug targets and accurate survival predictions in patients with HCC.

TQFL12, a novel synthetic derivative of TQ, inhibits triple-negative breast cancer metastasis and invasion through activating AMPK/ACC pathway

Thymoquinone (TQ) has been reported as an anti‐tumour drug widely studied in various tumours, and its mechanism and effect of which has become a focus of current research. However, previous studies from our laboratory and other groups found that TQ showed weak anti‐tumour effects in many cancer cell lines and animal models. Therefore, it is necessary to modify and optimize the structure of TQ to obtain new chemical entities with high efficiency and low toxicity as candidates for development of new drugs in treating cancer. Therefore, we designed and synthesized several TQ derivatives. Systematic analysis, including in vitro and in vivo, was conducted on a panel of triple‐negative breast cancer (TNBC) cells and mouse model to demonstrate whether TQFL12, a new TQ derivative, is more efficient than TQ. We found that the anti‐proliferative effect of TQFL12 against TNBC cells is significantly stronger than TQ. We also demonstrated TQFL12 affects different aspects in breast cancer development including cell proliferation, migration, invasion and apoptosis. Moreover, TQFL12 inhibited tumour growth and metastasis in cancer cell–derived xenograft mouse model, with less toxicity compared with TQ. Finally, mechanism research indicated that TQFL12 increased AMPK/ACC activity by stabilizing AMPKα, while molecular docking supported the direct interaction between TQFL12 and AMPKα. Taken together, our findings suggest that TQFL12, as a novel chemical entity, possesses a better inhibitory effect on TNBC cells and less toxicity in both in vitro and in vivo studies. As such, TQFL12 could serve as a potential therapeutic agent for breast cancer.

RIPK3 activation induces TRIM28 derepression in cancer cells and enhances the anti-tumor microenvironment

Background

Necroptosis is emerging as a new target for cancer immunotherapy as it is now recognized as a form of cell death that increases tumor immunogenicity, which would be especially helpful in treating immune-desert tumors. De novo synthesis of inflammatory proteins during necroptosis appears especially important in facilitating increased anti-tumor immune responses. While late-stage transcription mediated by NF-κB during cell death is believed to play a role in this process, it is otherwise unclear what cell signaling events initiate this transactivation of inflammatory genes.

Methods

We employed tandem-affinity purification linked to mass spectrometry (TAP-MS), in combination with the analysis of RNA-sequencing (RNA-Seq) datasets to identify the Tripartite Motif Protein 28 (TRIM28) as a candidate co-repressor. Comprehensive biochemical and molecular biology techniques were used to characterize the role of TRIM28 in RIPK3 activation-induced transcriptional and immunomodulatory events. The cell composition estimation module was used to evaluate the correlation between RIPK3/TRIM28 levels and CD8⁺ T cells or dendritic cells (DC) in all TCGA tumors.

Results

We identified TRIM28 as a co-repressor that regulates transcriptional activity during necroptosis. Activated RIPK3 phosphorylates TRIM28 on serine 473, inhibiting its chromatin binding activity, thereby contributing to the transactivation of NF-κB and other transcription factors, such as SOX9. This leads to elevated cytokine expression, which then potentiates immunoregulatory processes, such as DC maturation. The expression of RIPK3 has a significant positive association with the tumor-infiltrating immune cells populations in various tumor type, thereby activating anti-cancer responses.

Conclusion

Our data suggest that RIPK3 activation-dependent derepression of TRIM28 in cancer cells leads to increased immunostimulatory cytokine production in the tumor microenvironment, which then contributes to robust cytotoxic anti-tumor immunity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12943-021-01399-3.

TRIMming Down Hormone-Driven Cancers: The Biological Impact of TRIM Proteins on Tumor Development, Progression and Prognostication

The tripartite motif (TRIM) protein family is attracting increasing interest in oncology. As a protein family based on structure rather than function, a plethora of biological activities are described for TRIM proteins, which are implicated in multiple diseases including cancer. With hormone-driven cancers being among the leading causes of cancer-related death, TRIM proteins have been described to portrait tumor suppressive or oncogenic activities in these tumor types. This review describes the biological impact of TRIM proteins in relation to hormone receptor biology, as well as hormone-independent mechanisms that contribute to tumor cell biology in prostate, breast, ovarian and endometrial cancer. Furthermore, we point out common functions of TRIM proteins throughout the group of hormone-driven cancers. An improved understanding of the biological impact of TRIM proteins in cancer may pave the way for improved prognostication and novel therapeutics, ultimately improving cancer care for patients with hormone-driven cancers.

Targeting TRIM Proteins: A Quest towards Drugging an Emerging Protein Class

The ubiquitylation machinery regulates several fundamental biological processes from protein homeostasis to a wide variety of cellular signaling pathways. As a consequence, its dysregulation is linked to diseases including cancer, neurodegeneration, and autoimmunity. With this review, we aim to highlight the therapeutic potential of targeting E3 ligases, with a special focus on an emerging class of RING ligases, named tri-partite motif (TRIM) proteins, whose role as targets for drug development is currently gaining pharmaceutical attention. TRIM proteins exert their catalytic activity as scaffolds involved in many protein-protein interactions, whose multidomains and adapter-like nature make their druggability very challenging. Herein, we give an overview of the current understanding of this class of single polypeptide RING E3 ligases and discuss potential targeting options.

The translational values of TRIM family in pan-cancers: From functions and mechanisms to clinics

Cancer is the second leading cause of human death across the world. Tripartite motif (TRIM) family, with E3 ubiquitin ligase activities in majority of its members, is reported to be involved in multiple cellular processes and signaling pathways. TRIM proteins have critical effects in the regulation of biological behaviors of cancer cells. Here, we discussed the current understanding of the molecular mechanism of TRIM proteins regulation of cancer cells. We also comprehensively reviewed published studies on TRIM family members as oncogenes or tumor suppressors in the oncogenesis, development, and progression of a variety of types of human cancers. Finally, we highlighted that certain TRIM family members are potential molecular biomarkers for cancer diagnosis and prognosis, and potential therapeutic targets.

Prognostic significance of TRIM28 expression in patients with breast carcinoma

Background

Tripartite motif 28 (TRIM28) plays a role in multiple biological functions. The expression and function of TRIM28 in breast carcinoma (BC) remain unclear. The aim of this study was to explore potential association of TRIM28 with tumor features and survival.

Materials and methods

Specimens were collected from BC and adjacent normal tissues. Quantitative reverse transcription PCR (RT-qPCR) and immunohistochemistry (IHC) were performed to detect TRIM28 expression. The correlation of TRIM28 with clinicopathological features was evaluated by Chi-square test. The relationship between TRIM28 expression and survival was further analyzed by the Kaplan-Meier and Cox regression method. A receiver operating characteristic (ROC) curve was used to assess the value of TRIM28 in predicting BC.

Results

In this retrospective research, it was demonstrated that TRIM28 was overexpressed in BC tissues. TRIM28 overexpression was correlated with lymph node metastasis, advanced TNM stage, and poor molecular subtype. The survival analysis showed that overall survival (OS) and progression-free survival (PFS) were significantly shorter in TRIM28-positive group. Moreover, TRIM28 was an independent prognostic factor for BC. And ROC analysis verified the diagnostic role of TRIM28 in BC.

Conclusions

TRIM28 is overexpressed in BC and might be a promising prognostic and diagnostic biomarker of BC.

Zenglv Fumai Granule protects cardiomyocytes against hypoxia/reoxygenation-induced apoptosis via inhibiting TRIM28 expression

Myocardial ischemia/reperfusion (MIR) injury, which occurs following acute myocardial infarction, can cause secondary damage to the heart. Tripartite interaction motif (TRIM) proteins, a class of E3 ubiquitin ligases, have been recognized as critical regulators in MIR injury. Zenglv Fumai Granule (ZFG) is a clinical prescription for the treatment of sick sinus syndrome, a disease that is associated with MIR injury. The present study aimed to investigate the effect of ZFG on MIR injury and to determine whether ZFG exerts its effects via regulation of TRIM proteins. In order to establish an in vitro MIR model, human cardiomyocyte cell line AC16 was cultured under hypoxia for 5 h and then under normal conditions for 1 h. Following hypoxia/reoxygenation (H/R) treatment, these cells were cultured with different ZFG concentrations. ZFG notably inhibited H/R-induced cardiomyocyte apoptosis. The expression levels of four TRIM proteins, TRIM7, TRIM14, TRIM22 and TRIM28, were also detected. These four proteins were significantly upregulated in H/R-injured cardiomyocytes, whereas their expression was inhibited following ZFG treatment. Moreover, TRIM28 knockdown inhibited H/R-induced cardiomyocyte apoptosis, whereas TRIM28 overexpression promoted apoptosis and generation of reactive oxygen species (ROS) in cardiomyocytes. However, the effects of TRIM28 overexpression were limited by the action of ROS inhibitor N-acetyl-L-cysteine. In addition, the mRNA and protein levels of antioxidant enzyme glutathione peroxidase (GPX)1 were significantly downregulated in H/R-injured cardiomyocytes. TRIM28 knockdown restored GPX1 protein levels but had no effect on mRNA expression levels. Co-immunoprecipitation and ubiquitination assays demonstrated that TRIM28 negatively regulated GPX1 via ubiquitination. In sum, the present study revealed that ZFG attenuated H/R-induced cardiomyocyte apoptosis by regulating the TRIM28/GPX1/ROS pathway. ZFG and TRIM28 offer potential therapeutic options for the treatment of MIR injury.

Epigenetic modification and a role for the E3 ligase RNF40 in cancer development and metastasis

RNF40 (OMIM: 607700) is a really interesting new gene (RING) finger E3 ubiquitin ligase containing multiple coiled-coil domains and a C-terminal RING finger motif, which engage in protein–DNA and protein–protein interactions. RNF40 encodes a polypeptide of 1001 amino acids with a predicted molecular mass of 113,678 Da. RNF40 and its paralog RNF20 form a stable heterodimer complex that can monoubiquitylate histone H2B at lysine 120 as well as other nonhistone proteins. Cancer is a major public health problem and the second leading cause of death. Through its protein ubiquitylation activity, RNF40 acts as a tumor suppressor or oncogene to play major epigenetic roles in cancer development, progression, and metastasis, highlighting the essential function of RNF40 and the importance of studying it. In this review, we summarize current knowledge about RNF40 gene structure and the role of RNF40 in histone H2B monoubiquitylation, DNA damage repair, apoptosis, cancer development, and metastasis. We also underscore challenges in applying this information to cancer prognosis and prevention and highlight the urgent need for additional investigations of RNF40 as a potential target for cancer therapeutics.

lncRNA RP11-624L4.1 Is Associated with Unfavorable Prognosis and Promotes Proliferation via the CDK4/6-Cyclin D1-Rb-E2F1 Pathway in NPC

Nasopharyngeal carcinoma (NPC) is one of the most common malignant tumors in southern China and southeast Asia. Emerging evidence revealed that long noncoding RNAs (lncRNAs) might play important roles in the development and progression of many cancers, including NPC. The functions and mechanisms of the vast majority of lncRNAs involved in NPC remain unknown. In this study, a novel lncRNA RP11-624L4.1 was identified in NPC tissues using next-generation sequencing. In situ hybridization (ISH) was used to analyze the correlation between RP11-624L4.1 expression and the clinicopathological features or prognosis in NPC patients. RNA-Protein Interaction Prediction (RPISeq) predictions and RNA-binding protein immunoprecipitation (RIP) assays were used to identify RP11-624L4.1's interactions with cyclin-dependent kinase 4 (CDK4). As a result, we found that RP11-624L4.1 is hyper-expressed in NPC tissues, which was associated with unfavorable prognosis and clinicopathological features in NPC. By knocking down and overexpressing RP11-624L4.1, we also found that it promotes the proliferation ability of NPC in vitro and in vivo through the CDK4/6-Cyclin D1-Rb-E2F1 pathway. Overexpression of CDK4 in knocking down RP11-624L4.1 cells can partially rescue NPC promotion, indicating its role in the RP11-624L4.1-CDK4/6-Cyclin D1-Rb-E2F1 pathway. Taken together, RP11-624L4.1 is required for NPC unfavorable prognosis and proliferation through the CDK4/6-Cyclin D1-Rb-E2F1 pathway, which may be a novel therapeutic target and prognostic in patients with NPC.

Downregulation of miR-22 Contributes to Epithelial-Mesenchymal Transition in Osteosarcoma by Targeting Twist1

The epithelial-mesenchymal transition (EMT) is a vital step in osteosarcoma (OS) progression toward metastasis, but the specific molecular events governing this process are incompletely characterized, with miRNAs having increasingly been found to regulate the EMT. In this study, We assessed levels of miR-22 and its target, Twist1, via real-time PCR (qRT-PCR). We further used functional proliferation assays, measures of cell morphology, and western blotting to assess the functional relevance of miR-22 in OS and confirmed Twist1 as a miR-22 target via luciferase reporter assay. We observed a significant decrease in miR-22 levels in OS tumor samples relative to normal tissue, with such downregulating being significantly associated with tumor histological grade. When overexpressed, miR-22 impaired OS cell proliferation and EMT progression. We found Twist1 to be a direct miR-22 target, with levels of miR-22 and Twist1 mRNA being inversely correlated in patient samples. When overexpressed, miR-22 suppressed Twist1 translation and thereby attenuated the EMT in OS cells. These results clearly demonstrate that miR-22 can regulate the EMT in OS cells via targeting Twist1, thus highlighting a potentially novel pathway that can be therapeutically targeted in order to treat OS.

An ENU-induced mutation in Twist1 transactivation domain causes hindlimb polydactyly with complete penetrance and dominant-negatively impairs E2A-dependent transcription

Twist1 encodes a basic helix-loop-helix transcription factor (TF), which forms homodimer or heterodimer with other TFs, like E2A, to regulate target genes' expression. Mutations in TWIST1 are associated with Saethre-Chotzen syndrome (SCS), a rare congenital disorder characterized with osteogenesis abnormalities. However, how dysfunction of TWIST1 leads to SCS is still largely unknown. Here, using an unbiased ENU-induced mutagenesis screening, we identified a novel Twist1 mutation and the mutant mouse phenocopies some features of SCS in a dominant manner. Physically, our mutation p.F191S lies at the edge of a predicted α-helix in Twist1 transactivation (TA) domain. Adjacent to F191, a consecutive three-residue (AFS) has been hit by 3 human and 2 mouse disease-associated mutations, including ours. Unlike previously reported mouse null and p.S192P alleles that lead to hindlimb polydactyly with incomplete penetrance but a severe craniofacial malformation, our p.F191S causes the polydactyly (84.2% bilateral and 15.8% unilateral) with complete penetrance but a mild craniofacial malformation. Consistent with the higher penetrance, p.F191S has stronger impairment on E2A-dependent transcription than p.S192P. Although human p.A186T and mouse p.S192P disease mutations are adjacent to ours, these three mutations function differently to impair the E2A-dependent transcription. Unlike p.A186T and p.S192S that disturb local protein conformation and unstabilize the mutant proteins, p.F191S keeps the mutant protein stable and its interaction with E2A entire. Therefore, we argue that p.F191S we identified acts in a dominant-negative manner to impair E2A-dependent transcription and to cause the biological consequences. In addition, the mutant mouse we provided here could be an additional and valuable model for better understanding the disease mechanisms underlying SCS caused by TWIST1 dysfunction.

High Expression of TRIM15 Is Associated with Tumor Invasion and Predicts Poor Prognosis in Patients with Gastric Cancer

BACKGROUND

Gastric cancer is the third leading cause of cancer-related mortality worldwide. Most tripartite motif (TRIM) family proteins are known as E3 ubiquitin ligases and considerable previous research has revealed the involvement of TRIM proteins in carcinogenesis. TRIM15 is a protein from the TRIM family and the aim of this study is to investigate the role of TRIM15 in gastric cancer.

METHODS

We conducted immunohistochemical staining to examine TRIM15 expression using samples from Zhongshan Hospital of Fudan University. We also conducted transwell assay as well as western blot by using gastric cancer cells.

RESULTS

The expression of TRIM15 in gastric cancer tissues was higher than normal tissues. Present data demonstrated that high TRIM15 staining intensity had a positive relation to tumor invasion depth (P = 0.007), lymph node metastasis (P = 0.013), distant metastasis (P = 0.031), the tumor-node-metastasis (TNM) staging system (P = 0.002) and shorter overall survival (OS) in gastric cancer patients (P < 0.001). It was also worthwhile mentioning that TRIM15 was an adverse prognostic variable for OS. To gain more insight, we incorporated TRIM15 expression into the tumor-node-metastasis (TNM) staging system and thus established a nomogram. Data derived from the nomogram suggested that fitting TRIM15 expression into the prognostic model exhibited better efficiency for predicting OS in gastric cancer patients. Furthermore, TRIM15 promoted migration, invasion and epithelial-mesenchymal transition of gastric cancer cells.

CONCLUSIONS

Together, TRIM15 expression was found as a specific and independent adverse predictor in gastric cancer patients and the nomogram may contribute to better clinical management.

Knockdown of TRIM28 inhibits PDGF-BB-induced vascular smooth muscle cell proliferation and migration

Atherosclerosis is a common type of cardiovascular disease (CVD), remaining one of the leading causes of global death. Tripartite motif-containing 28 (TRIM28) is a member of TRIM family that has been found to be involved in atherosclerosis. However, the role of TRIM28 in atherosclerosis remains unknown. This study aimed to investigate the effects of TRIM28 on the phenotypic switching of human aortic smooth muscle cells (HASMCs), which is considered as a fundamental event during the development of atherosclerosis. The results showed that TRIM28 was highly expressed in human atherosclerotic tissues, as well in cultured HASMCs stimulated by platelet-derived growth factor subunit B homodimer (PDGF-BB). Knockdown of TRIM28 by transfection with siRNA targeting TRIM28 (si-TRIM28) significantly suppressed the PDGF-BB-induced cell proliferation and migration of HASMCs. Besides, knockdown of TRIM28 inhibited the expressions of matrix metalloproteinase (MMP)-2 and MMP-9. The VSMC markers including α-smooth muscle actin (α-SMA), calponin and SM22α were upregulated in TRIM28 knocked down HASMCs. Furthermore, knockdown of TRIM28 blocked PDGF-BB-induced NF-κB activation in HASMCs. Collectively, knockdown of TRIM28 prevented PDGF-BB-induced phenotypic switching of HASMCs, which might be mediated by the regulation of NF-κB signaling pathway.

TRIM28 protects CARM1 from proteasome-mediated degradation to prevent colorectal cancer metastasis

TRIM28 (Tripartite motif-containing protein 28), a member of TRIM family, is aberrantly expressed and reportedly has different functions in many types of human cancer. However, the biological roles of TRIM28 and related mechanism in colorectal cancer (CRC) remain unclear. Here, we showed that TRIM28 was downregulated in colorectal cancer compared with normal mucosa, especially at advanced stages, and acted as an independent prognostic factor of favorable outcome. Functional studies demonstrated that TRIM28 restrained CRC migration and invasion in vitro and in vivo. Mechanistically, we reported that CARM1 (co-activator-associated arginine methyltransferase1) was a critical player downstream of TRIM28. TRIM28 interacted with CARM1, and protected CARM1 from proteasome-mediated degradation through physical protein-protein interaction to suppress CRC metastasis. Further, TRIM28 suppressed the migration and invasion of CRC cells through inhibiting WNT/β-catenin signaling in a CARM1-dependent manner, but independent of CARM1's methyltransferase activity. The protein expression of CARM1 was positively correlated with TRIM28 in CRC tissues. Patients with high levels of TRIM28 and CARM1 had improved prognosis, whereas patients with low TRIM28 and CARM1 expression had the poor outcomes. Thus, our study reveals an inhibitory role of TRIM28 in CRC metastasis, which was achieved through a TRIM28-CARM1-WNT/β-catenin axis. This work provides potential prognostic and therapeutic targets for CRC treatment.

E3 Ubiquitin Ligase TRIM Proteins, Cell Cycle and Mitosis

The cell cycle is a series of events by which cellular components are accurately segregated into daughter cells, principally controlled by the oscillating activities of cyclin-dependent kinases (CDKs) and their co-activators. In eukaryotes, DNA replication is confined to a discrete synthesis phase while chromosome segregation occurs during mitosis. During mitosis, the chromosomes are pulled into each of the two daughter cells by the coordination of spindle microtubules, kinetochores, centromeres, and chromatin. These four functional units tie chromosomes to the microtubules, send signals to the cells when the attachment is completed and the division can proceed, and withstand the force generated by pulling the chromosomes to either daughter cell. Protein ubiquitination is a post-translational modification that plays a central role in cellular homeostasis. E3 ubiquitin ligases mediate the transfer of ubiquitin to substrate proteins determining their fate. One of the largest subfamilies of E3 ubiquitin ligases is the family of the tripartite motif (TRIM) proteins, whose dysregulation is associated with a variety of cellular processes and directly involved in human diseases and cancer. In this review we summarize the current knowledge and emerging concepts about TRIMs and their contribution to the correct regulation of cell cycle, describing how TRIMs control the cell cycle transition phases and their involvement in the different functional units of the mitotic process, along with implications in cancer progression.

miR-140-3p inhibits breast cancer proliferation and migration by directly regulating the expression of tripartite motif 28

The present study aimed to determine the expression profile and significance of microRNA-140-3p (miR-140-3p) in breast cancer (BC). miR-140-3p expression in BC tumor tissues and cell lines was measured by reverse transcription-quantitative polymerase chain reaction. Luciferase activity reporter assay and western blotting were used to assess the effect of miR-140-3p expression on tripartite motif 28 (TRIM28). Cell growth, migration, and invasion were assessed by Cell Counting Kit-8 assay, wound-healing assay and Transwell invasion assay, respectively. miR-140-3p expression was significantly reduced in BC tumor tissues compared with in adjacent normal tissues. Additionally, low miR-140-3p expression was found to predict poor prognosis of patients with BC. TRIM28 expression was significantly reduced by miR-140-3p overexpression in BC cell lines, and was inversely correlated with miR-140-3p in BC tissues. Overexpression of miR-140-3p also inhibited cell proliferation, migration and invasion compared with in the control group. In conclusion, the present study revealed that miR-140-3p inhibited the progression of BC partially by regulating TRIM28.

TRIM28 activates autophagy and promotes cell proliferation in glioblastoma

Background

Tripartite motif-containing protein 28 (TRIM28) is a transcriptional corepressor involved in the regulation of several cancers, including glioma. It has been reported that TRIM28 takes part in the process of autophagy. However, its effect on the autophagy and cell proliferation in gliomas has not been elucidated. Here, we report a novel tumor cell proliferation mechanism in which TRIM28-regulated autophagy promotes glioma tumor cell proliferation.

Materials and methods

We analyzed the expressions of TRIM28 and LC3 in different WHO grades of gliomas by IHC assays. We then knocked down and overexpressed TRIM28 or knocked down ATG5 in U251 cells and confirmed its roles in autophagy and cell proliferation via cell counting, immunofluorescence, and Western blot.

Results

The results showed that TRIM28 and autophagy levels were significantly increased with the progression of tumor grade in glioma. TRIM28 promoted glioblastoma cell proliferation. Knockdown of TRIM28 inhibited autophagy in glioblastoma cells. Meanwhile, TRIM28 promoted glioblastoma cell proliferation by modulating TRIM28.

Conclusion

These data demonstrated that TRIM28 activates autophagy and increases cell proliferation in glioma.

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.

Negative Regulation of BOK Expression by Recruitment of TRIM28 to Regulatory Elements in Its 3' Untranslated Region

BCL-2-related ovarian killer (BOK) is a pro-apoptotic BAX-like member of the BCL-2 family with suggested tumor suppressor activity. The molecular mechanisms regulating BOK expression are poorly understood and fail to explain a frequent lack of concordance between protein and transcript levels. Here, we describe a potent post-transcriptional mechanism that negatively regulates BOK expression mediated by conserved (AU/U)-rich elements within its 3’ UTR. Using proteomics approaches we identified TRIM28 as a key component associating with U-rich elements in the human BOK 3’ UTR, resulting in a dramatic reduction of BOK expression. TRIM28 is overexpressed in several cancers, correlating with poor patient outcome, whereas the BOK locus is frequently deleted or its expression downregulated in human cancers. Data mining indicated that, for certain cancers, high TRIM28 and low BOK expression are significantly correlated in the stratum of patients with the worst survival, suggesting that this mechanism might be of potential therapeutic value.

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BOK mRNA is destabilized by AU-(mouse) or U-rich (human) elements within its 3’ UTR

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Mutation of these ARE/URE sequences results in increased BOK RNA and protein levels

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TRIM28 represses BOK expression by associating with the UREs of human BOK mRNA

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Inverse correlation of TRIM28 and BOK levels predicts survival in selected cancers

TRIM28 is overexpressed in glioma and associated with tumor progression

Background

Tripartite motif containing 28 (TRIM28) is a transcriptional co-factor targeting many genes with pleiotropic biological activities, but the study on the role of TRIM28 in glioma is rare.

Methods

To explore the function of TRIM28 in glioma, we first detected the expression levels of TRIM28 in glioma tissues and analyzed the correlations of TRIM28 expression with clinicopathological variables of patients in 85 cases of glioma. Meanwhile, we used shRNA to knockdown TRIM28 in glioma cell lines to detect the biological functions of TRIM28 in cell and animal experiments.

Results

We found that TRIM28 was expressed at significantly higher level in glioma tissues than in non-tumor brain, and TRIM28 expression correlated significantly with tumor malignancy. Furthermore, TRIM28 higher expression was also correlated with poor survival of glioma patients (P<0.01). Functionally, knockdown of TRIM28 could significantly inhibit cell proliferation and migration in glioma cells. Additionally, we found that TRIM28 could inhibit the expression of E-cadherin significantly by reducing its mRNA stability at the post-transcriptional level.

Conclusion

Our results suggest that TRIM28 overexpression is correlated with glioma malignant progression and patients' poor survival, so targeting TRIM28 could be an efficacious strategy in glioma.

The SUMO System and TGFβ Signaling Interplay in Regulation of Epithelial-Mesenchymal Transition: Implications for Cancer Progression

Protein post-translational modification by the small ubiquitin-like modifier (SUMO), or SUMOylation, can regulate the stability, subcellular localization or interactome of a protein substrate with key consequences for cellular processes including the Epithelial-Mesenchymal Transition (EMT). The secreted protein Transforming Growth Factor beta (TGFβ) is a potent inducer of EMT in development and homeostasis. Importantly, the ability of TGFβ to induce EMT has been implicated in promoting cancer invasion and metastasis, resistance to chemo/radio therapy, and maintenance of cancer stem cells. Interestingly, TGFβ-induced EMT and the SUMO system intersect with important implications for cancer formation and progression, and novel therapeutics identification.

A regulatory mutant on TRIM26 conferring the risk of nasopharyngeal carcinoma by inducing low immune response

The major histocompatibility complex (MHC) is most closely associated with nasopharyngeal carcinoma (NPC), but the complexity of its genome structure has proven challenging for the discovery of causal MHC loci or genes. We conducted a targeted MHC sequencing in 40 Cantonese NPC patients followed by a two‐stage replication in 1065 NPC cases and 2137 controls of Southern Chinese descendent. Quantitative RT‐PCR analysis (qRT‐PCR) was used to detect gene expression status in 108 NPC and 43 noncancerous nasopharyngeal (NP) samples. Luciferase reporter assay and chromatin immunoprecipitation (ChIP) were used to assess the transcription factor binding site. We discovered that a novel SNP rs117565607_A at TRIM26 displayed the strongest association (OR = 1.909, Pcombined = 2.750 × 10⁻¹⁹). We also observed that TRIM26 was significantly downregulated in NPC tissue samples with genotype AA/AT than TT. Immunohistochemistry (IHC) test also found the TRIM26 protein expression in NPC tissue samples with the genotype AA/AT was lower than TT. According to computational prediction, rs117565607 locus was a binding site for the transcription factor Yin Yang 1 (YY1). We observed that the luciferase activity of YY1 which is binding to the A allele of rs117565607 was suppressed. ChIP data showed that YY1 was binding with T not A allele. Significance analysis of microarray suggested that TRIM26 downregulation was related to low immune response in NPC. We have identified a novel gene TRIM26 and a novel SNP rs117565607_A associated with NPC risk by regulating transcriptional process and established a new functional link between TRIM26 downregulation and low immune response in NPC.

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.

Development of diagnostic SCAR markers for genomic DNA amplifications in breast carcinoma by DNA cloning of high-GC RAMP-PCR fragments

Cancer is genetically heterogeneous regarding to molecular genetic characteristics and pathogenic pathways. A wide spectrum of biomarkers, including DNA markers, is used in determining genomic instability, molecular subtype determination and disease prognosis, and estimating sensitivity to different drugs in clinical practice. In a previous study, we developed highly effective DNA markers using improved random amplified polymorphic DNA (RAPD) with high-GC primers, which is a valuable approach for the genetic authentication of medicinal plants. In this study, we applied this effective DNA marker technique to generate genetic fingerprints that detect genomic alterations in human breast cancer tissues and then developed sequence-characterized amplified region (SCAR) markers. Three SCAR markers (BC10-1, BC13-4 and BC31-2) had high levels of genomic DNA amplification in breast cancer. The PHKG2 and RNF40 genes are either overlapping or close to the sequences of SCAR marker BC13-4, while SCAR marker BC10-1 is in the intron and overlap the DPEP1 gene, suggesting that alterations in the expression of these genes could contribute to cancer progression. Screening of breast cancer cell lines showed that the mRNA expression levels for the PHKG2 and DPEP1 were lower in non-tumorigenic mammary epithelial cell MCF10A, but elevated in other cell lines. The DPEP1 mRNA level in invasive ductal carcinoma specimens was significantly higher than that of the adjacent normal tissues in women. Taken together, high-GC RAMP-PCR provides greater efficacy in measuring genomic DNA amplifications, deletion or copy number variations. Furthermore, SCAR markers BC10-1 and BC13-4 might be useful diagnostic markers for breast cancer carcinomas.

TRIM14 Promotes Breast Cancer Cell Proliferation by Inhibiting Apoptosis

Tripartite motif-containing 14 (TRIM14) is abnormally expressed in several human cancers. However, the function and expression of TRIM14 in human breast cancer are still largely unknown. To understand the biological function of TRIM14 in breast cancer, we measured the expression level of TRIM14. Cell proliferation and cell apoptosis were measured after TRIM14 overexpression or knockdown. Upregulation of TRIM14 was found in human breast cancer specimens and cell lines. Reduction of TRIM14 inhibited cell proliferation but increased cell apoptosis in the BT474 and MDA-MB-231 cell lines. Further study showed that knockdown of TRIM14 upregulated the expression of BAX while downregulating the expression of BCL2. In addition, the expression of SHP-1 was increased, and the phosphorylation of STAT3 (p-STAT3) was inhibited. Conversely, overexpression of TRIM14 had the opposite effects. Additionally, cryptotanshinone, a STAT3 inhibitor, inhibited cell proliferation but increased cell apoptosis in the BT474 and MDA-MB-231 cell lines. In conclusion, TRIM14 may act as an oncogene in human breast cancer and may be a novel strategy for human breast cancer.

The lncRNA BORG Drives Breast Cancer Metastasis and Disease Recurrence

Long noncoding RNAs (lncRNAs) have emerged as potent regulators of breast cancer development and progression, including the metastatic spread of disease. Through in silico and biological analyses, we identified a novel lncRNA, BMP/OP-Responsive Gene (BORG), whose expression directly correlates with aggressive breast cancer phenotypes, as well as with metastatic competence and disease recurrence in multiple clinical cohorts. Mechanistically, BORG elicits the metastatic outgrowth of latent breast cancer cells by promoting the localization and transcriptional repressive activity of TRIM28, which binds BORG and induces substantial alterations in carcinoma proliferation and survival. Moreover, inhibiting BORG expression in metastatic breast cancer cells impedes their metastatic colonization of the lungs of mice, implying that BORG acts as a novel driver of the genetic and epigenetic alterations that underlie the acquisition of metastatic and recurrent phenotypes by breast cancer cells.