TRIM29 negatively regulates p53 via inhibition of Tip60

TRIM-endous functional network of tripartite motif 29 (TRIM29) in cancer progression and beyond

While most Tripartite motif (TRIM) family proteins are E3 ubiquitin ligases, some members have functions beyond the regulation of ubiquitination, impacting normal physiological processes and disease progression. TRIM29, an important member of the TRIM family, exerts a predominant influence on cancer growth, epithelial-to-mesenchymal transition, stemness and metastatic progression by directly potentiating multiple canonical oncogenic pathways. The cancer-promoting effect of TRIM29 is also evident in metabolic interventions and interference with the efficacy of cancer therapeutics. As expected for any key node in cancer, the expression of TRIM29 is tightly regulated by non-coding RNAs, epigenetic modulation, and post-translational regulation. A systematic discussion of how TRIM29 is regulated in cancer, its influences on cancer progression, and its impact on cancer therapeutics is presented in this review. We also explore the context-dependent alterations between TRIM29 function from oncogenic to tumor suppression. As TRIM29 is involved in multiple aspects of cancer progression, a better understanding of its biological impact in cancer may help improve prognosis and develop novel therapeutic combinations, leading to improved personalized cancer care.

TRIM16 and PRC1 Are Involved in Pancreatic Cancer Progression and Targeted by Delphinidin

Pancreatic cancer (PC) is the leading cause of cancer-related death worldwide, and new biomarkers, therapeutic targets, and candidate drugs are needed. In this work, three PC-related microarray datasets (GSE183795, GSE28735, and GSE62452) were analyzed. The differentially expressed genes (DEGs) of PC were obtained with the limma package in R. Weighted gene co-expression network analysis (WGCNA) and machine learning approaches were used to screen the hub genes. Kaplan-Meier plotter and receiver operating characteristic (ROC) curve analysis were utilized to assess the diagnostic efficacy of the hub genes. The binding ability between natural bioactive ingredients and hub proteins was evaluated by molecular docking and molecular dynamics simulation. CCK-8, flow cytometry, transwell, and western blot assays were used to analyze the viability, apoptosis, cell cycle progression, invasion, and pathway change of PC cells. Additionally, a nude mice model was used to evaluate the aggressive properties of PC cells in vivo. In this study, a total of 988 DEGs were identified, which were mainly enriched in cell adhesion and PI3K-Akt signaling pathway, and two core genes TRIM16 and PRC1 were further identified. The overall survival of patients with high expression of TRIM16 and PRC1 was shorter. Delphinidin (Del) had good binding affinity with both TRIM16 and PRC1, and Del could inhibit the viability, invasion, and metastasis of PC cells and induce cell apoptosis and G0/G1 phase arrest. In addition, Del could promote the activation of p53 and inhibit the activation of the PI3K/AKT signaling pathway in PC cells. In summary, TRIM16 and PRC1 are identified as prognostic biomarkers and therapeutic targets for PC, and Del has good binding affinity with them and may be a potential therapeutic agent for PC.

Development and validation of a TRIM27-based nomogram for predicting metachronous liver metastasis and prognosis in postoperative colorectal cancer patients

BACKGROUND

Colorectal cancer ranks among the most prevalent malignancies globally. Accurate prediction of metachronous liver metastasis is crucial for optimizing postoperative management. Tripartite motif-containing protein 27 (TRIM27), an E3 ubiquitin ligase, is implicated in diverse cellular functions and tumorigenesis.

METHODS

This study aimed to develop and validate a TRIM27-based nomogram for prognostication in colorectal cancer patients. Transcriptome sequencing of five paired tumor and normal tissue samples identified TRIM27 as a potential prognostic biomarker. Immunohistochemistry was employed to assess TRIM27 expression in colorectal cancer cohorts from two institutions.

RESULTS

TRIM27 expression correlated significantly with both the prognosis of colorectal cancer patients and the occurrence of metachronous liver metastasis. A nomogram incorporating TRIM27 and clinical factors was constructed and demonstrated robust predictive accuracy in an independent validation cohort.

CONCLUSION

The TRIM27-based nomogram is a valuable prognostic tool for predicting prognosis and metachronous liver metastasis in colorectal cancer patients, aiding in personalized treatment decisions.

TRIM29 facilitates gemcitabine resistance via MEK/ERK pathway and is modulated by circRPS29/miR-770-5p axis in PDAC

AIMS

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease. Chemotherapy based on gemcitabine (GEM) remains the first-line drug for patients with advanced PDAC. However, GEM resistance impairs its therapeutic effectiveness. Therefore, identifying effective therapeutic targets are urgently needed to overcome GEM resistance.

METHODS

The clinical significance of Tripartite Motif Containing 29 (TRIM29) was identified by exploring GEO datasets and TCGA database and its potential biological functions were predicted by GSEA analysis. The regulatory axis was established by bioinformatics analysis and validated by mechanical experiments. Then, in vitro and in vivo assays were performed to validate the roles of TRIM29 in PDAC GEM resistance.

RESULTS

High TRIM29 expression was associated with poor prognosis of PDAC and functional experiments demonstrated that TRIM29 promoted GEM resistance in PDAC GEM-resistant (GR) cells. Furthermore, we revealed that circRPS29 promoted TRIM29 expression via competitive interaction with miR-770-5p and then activated MEK/ERK signaling pathway. Additionally, both in vitro and in vivo functional experiments demonstrated that circRPS29/miR-770-5p/TRIM29 axis promoted PDAC GEM resistance via activating MEK/ERK signaling pathway.

CONCLUSION

Our results identify the significance of the signaling axis, circRPS29/miR-770-5p/TRIM29-MEK/ERK, in PDAC GEM resistance, which will provide novel therapeutic targets for PDAC treatment.

TRIM29 modulates proteins involved in PTEN/AKT/mTOR and JAK2/STAT3 signaling pathway and suppresses the progression of hepatocellular carcinoma

Tripartite motif-containing 29 (TRIM29), also known as the ataxia telangiectasia group D-complementing (ATDC) gene, has been reported to play an oncogenic or tumor suppressive role in developing different tumors. So far, its expression and biological functions in hepatocellular carcinoma (HCC) remain unclear. We investigated TRIM29 expression pattern in human HCC samples using quantitative RT-PCR and immunohistochemistry. Relationships between TRIM29 expression level, clinical prognostic indicators, overall survival (OS), and disease-free survival (DFS) were evaluated by Kaplan-Meier analysis and Cox proportional hazards model. A series of in vitro experiments and a xenograft tumor model were conducted to detect the functions of TRIM29 in HCC cells. RNA sequencing, western blotting, and immunochemical staining were performed to assess the molecular regulation of TRIM29 in HCC. We found that the mRNA and protein levels of TRIM29 were significantly reduced in HCC samples, compared with adjacent noncancerous tissues, and were negatively correlated with poor differentiation of HCC tissues. Survival analysis confirmed that lower TRIM29 expression significantly correlated with shorter OS and DFS of HCC patients. TRIM29 overexpression remarkably inhibited cell proliferation, migration, and EMT in HCC cells, whereas knockdown of TRIM29 reversed these effects. Moreover, deactivation of the PTEN/AKT/mTOR and JAK2/STAT3 pathways might be involved in the tumor suppressive role of TRIM29 in HCC. Our findings indicate that TRIM29 in HCC exerts its tumor suppressive effects through inhibition of the PTEN/AKT/mTOR and JAK2/STAT3 signaling pathways and may be used as a potential biomarker for survival in patients with HCC.

TRIM29 promotes antitumor immunity through enhancing IGF2BP1 ubiquitination and subsequent PD-L1 downregulation in gastric cancer

Tripartite motif-containing protein 29 (TRIM29) is a member of TRIM family protein which has been reported to play a role in the progress of inflammatory and cancer diseases. However, its specific role in gastric cancer (GC) has yet to be fully understood. Here, we investigated the expression of TRIM29 in gastric cancer and its functions in the antitumor immunity. TRIM29 expression was lower in tumor tissues than that in paired normal tissues. Lower expression of TRIM29 was related to aberrant hypermethylation of CpG islands in TRIM29 gene. Comprehensive proteomics and immunoprecipitation analyses identified IGF2BP1 as TRIM29 interactors. TRIM29 interacted with IGF2BP1 and induced its ubiquitination at Lys440 and Lys450 site by K48-mediated linkage for protein degradation. IGF2BP1 promoted PD-L1 mRNA stability and expression in a 3'UTR and m6A-dependent manner. Functionally, TRIM29 enhanced antitumor T-cell immunity in gastric cancer dependent on the IGF2BP1/PD-L1 axis in vivo and in vitro. Clinical correlation analysis revealed that TRIM29 expression in patient samples was associated with CD8+ immune cell infiltration in the GC microenvironment and the overall survival rates of GC patients. Our findings revealed a crucial role of TRIM29 in regulating the antitumor T-cell immunity in GC. We also suggested that the TRIM29/IGF2BP1/PD-L1 axis could be used as a diagnostic and prognostic marker of gastric cancer and a promising target for GC immunotherapy.

Suppression of protein quality control system by TRIM30a sensitises tumour cells to NK cell-mediated immune surveillance

Tumorigenesis entails circumventing cell-intrinsic regulatory mechanisms while avoiding extrinsic immune surveillance and other host defence systems. Nevertheless, how tumour cells' ability to eliminate misfolded proteins affects immune surveillance remains poorly understood. In this study, we find that overexpression of murine tripartite motif-containing protein 30a (TRIM30a) sensitises tumour cells to natural killer (NK) cells-mediated cytolysis. TRIM30a has no effect on tumour cell proliferation or apoptosis in vitro. However, TRIM30a-overexpressing tumour cells grow substantially slower than control tumour cells in immune-competent mice but not in NK cell-depleted mice. [Correction added on 04 October 2023, after first online publication: 'NK-depleted' has been changed to 'NK cell-depleted' in the preceding sentence.] Mechanistically, TRIM30a overexpression impedes the clearance of misfolded proteins and increases the production of reactive oxygen species induced by proteotoxic stress, implying that TRIM30a impairs protein quality control (PQC) systems in tumour cells. Furthermore, TRIM30a reduces expression of genes encoding proteasome subunits and antioxidant proteins. Our study demonstrates that TRIM30a is a potential tumour suppressor and immune modulator that promotes tumour cytolysis by NK cells, and suggests that an enhanced PQC and antioxidant capacity is an integral part of the immune escape mechanism during tumorigenesis.

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.

Alteration in Expression of Trim29, TRIM37, TRIM44, and β-Catenin Genes After Irradiation in Human Cells with Different Radiosensitivity

Introduction: Radiotherapy is a crucial component of treatment for ∼70% of all cancer patients. The identification of effective biomarkers of radiosensitivity (RS) is a fundamental goal of radiobiology. The authors hypothesize that the RS of human normal and tumoral cells is correlated by the level of expression of TRIM29, TRIM37, TRIM44, and β-catenin genes. Materials and Methods: Clonogenic assay was performed and RS of four cell lines was determined by survival fraction at 2 Gy. To determine the level of gene expression 6 and 24 h after irradiation, RNA was extracted from each cell line, and expression of the above-mentioned genes in cell lines with different RS was determined by real-time polymerase chain reaction (PCR). Results: The clonogenic assay showed that human dermal fibroblasts (fibroblast) and HT-29 (colorectal) cells are radioresistant, while human foreskin fibroblasts (fibroblast) and QU-DB (lung) cells are radiosensitive. Analysis of the real-time PCR data, 6 h after irradiation, showed that the increase and decrease of the expression of TRIM29 and TRIM37 genes were directly correlated with the RS of normal and tumor cells. At 24 h postirradiation, a considerable difference was only observed in the expression of the β-catenin gene. Conclusion: This study showed that the TRIM29 and TRIM37 genes are involved in the cell response to radiation and proposed that these genes may be biomarkers for predicting RS in normal and tumoral cell lines.

circRNA_0067717 promotes paclitaxel resistance in nasopharyngeal carcinoma by acting as a scaffold for TRIM41 and p53

PURPOSE

Circular RNAs (circRNAs) play important roles in tumour progression. This study aimed to explore the mechanism of hsa_circ_0067717 (termed circRNA_0067717) promoting paclitaxel resistance in nasopharyngeal carcinoma (NPC).

METHODS

We assayed CNE-1 and HNE-2 parental cell lines and the corresponding paclitaxel-resistant NPC cell lines using circRNA microarrays. RNA pull-down assay, RNA immunoprecipitation, and RNA fluorescence in situ hybridization were used to identify the molecular mechanisms.

RESULTS

Here, we confirm that circRNA_0067717 is significantly upregulated in NPC paclitaxel-resistant cells and is associated with paclitaxel resistance in NPC. Mechanistically, circRNA_0067717 functions as a scaffold for TRIM41 protein (a ubiquitin E3 ligase) and p53 protein. In nasopharyngeal carcinoma paclitaxel-resistant cells, the highly expressed circRNA_0067717 can bind to more TRIM41 and p53 protein, promoting TRIM41-induced p53 ubiquitination and degradation, resulting in a decrease in p53 protein level. Moreover, the 1-176 nt area of circRNA_0067717 and the 301-425 nt region of circRNA_0067717 are the binding sites for p53 and TRIM41, respectively. The resistance of NPC cells to paclitaxel can be reduced by blocking these binding regions of circRNA_0067717.

CONCLUSION

We demonstrate that circRNA_0067717 acts as a scaffold for TRIM41 and p53, enhancing paclitaxel chemoresistance in NPC by promoting TRIM41-induced p53 degradation via ubiquitination.

Insights into Regulators of p53 Acetylation

The tumor suppressor p53 is a transcription factor that regulates the expression of dozens of target genes and diverse physiological processes. To precisely regulate the p53 network, p53 undergoes various post-translational modifications and alters the selectivity of target genes. Acetylation plays an essential role in cell fate determination through the activation of p53. Although the acetylation of p53 has been examined, the underlying regulatory mechanisms remain unclear and, thus, have attracted the interest of researchers. We herein discuss the role of acetylation in the p53 pathway, with a focus on p53 acetyltransferases and deacetylases. We also review recent findings on the regulators of these enzymes to understand the mode of p53 acetylation from a broader perspective.

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.

The roles and targeting options of TRIM family proteins in tumor

Tripartite motif (TRIM) containing proteins are a class of E3 ubiquitin ligases, which are critically implicated in the occurrence and development of tumors. They can function through regulating various aspects of tumors, such as tumor proliferation, metastasis, apoptosis and the development of drug resistance during tumor therapy. Some members of TRIM family proteins can mediate protein ubiquitination and chromosome translocation via modulating several signaling pathways, like p53, NF-κB, AKT, MAPK, Wnt/β-catenin and other molecular regulatory mechanisms. The multi-domain nature/multi-functional biological role of TRIMs implies that blocking just one function or one domain might not be sufficient to obtain the desired therapeutic outcome, therefore, a detailed and systematic understanding of the biological functions of the individual domains of TRIMs is required. This review mainly described their roles and underlying mechanisms in tumorigenesis and progression, and it might shade light on a potential targeting strategy for TRIMs in tumor treatment, especially using PROTACs.

Chromatin Dynamics in Digestive System Cancer: Commander and Regulator

Digestive system tumors have a poor prognosis due to complex anatomy, insidious onset, challenges in early diagnosis, and chemoresistance. Epidemiological statistics has verified that digestive system tumors rank first in tumor-related death. Although a great number of studies are devoted to the molecular biological mechanism, early diagnostic markers, and application of new targeted drugs in digestive system tumors, the therapeutic effect is still not satisfactory. Epigenomic alterations including histone modification and chromatin remodeling are present in human cancers and are now known to cooperate with genetic changes to drive the cancer phenotype. Chromatin is the carrier of genetic information and consists of DNA, histones, non-histone proteins, and a small amount of RNA. Chromatin and nucleosomes control the stability of the eukaryotic genome and regulate DNA processes such as transcription, replication, and repair. The dynamic structure of chromatin plays a key role in this regulatory function. Structural fluctuations expose internal DNA and thus provide access to the nuclear machinery. The dynamic changes are affected by various complexes and epigenetic modifications. Variation of chromatin dynamics produces early and superior regulation of the expression of related genes and downstream pathways, thereby controlling tumor development. Intervention at the chromatin level can change the process of cancer earlier and is a feasible option for future tumor diagnosis and treatment. In this review, we introduced chromatin dynamics including chromatin remodeling, histone modifications, and chromatin accessibility, and current research on chromatin regulation in digestive system tumors was also summarized.

TRIM3 Inhibits H2O2-Induced Apoptosis in Human Lens Epithelial Cells by Decreasing p53 via Ubiquitination

PURPOSE

Cataract is a leading visual disease characterized by enhanced oxidative stress and increased apoptosis of human lens epithelial cells (HLECs). TRIM3 is a tumor suppressor in many cancers. However, its role in cataract remains unknown. In this study, we aimed to explore the role of TRIM3 in H₂O₂-injured HLECs and the underlying mechanisms involved.

METHODS

HLECs were treated with different H₂O₂ concentrations to induce apoptosis. A lentivirus was designed to overexpress TRIM3 and p53, and TRIM3 knockdown was prepared. A P53 inhibitor, PFTα, was used to knockdown p53. Cell viability and apoptosis were detected by CCK-8 and flow cytometric analyses, respectively. TRIM3, p53, Bcl2, and Bax expression levels were determined by qRT-qPCR and western blotting.

RESULTS

It was found that H₂O₂-treated HLECs had markedly decreased cell viability and TRIM3 expression. TRIM3 overexpression attenuated the H₂O₂-induced HLEC apoptosis, while TRIM3 knockdown promoted it. P53, a downstream target of TRIM3, was found to be negatively regulated by TRIM3 via ubiquitination in HLECs. Furthermore, p53 overexpression abolished the effect of TRIM3 overexpression on H₂O₂-induced HLEC apoptosis, while PFTα alleviated the TRIM3 knockdown-mediated HLEC apoptosis.

CONCLUSION

This study demonstrates that TRIM3 inhibited the H₂O₂-induced apoptosis of HLECs by decreasing p53 via ubiquitination.

TRIM29 in Cutaneous Squamous Cell Carcinoma

Tripartite motif (TRIM) proteins play important roles in a wide range of cell physiological processes, such as signal transduction, transcriptional regulation, innate immunity, and programmed cell death. TRIM29 protein, encoded by the ATDC gene, belongs to the RING-less group of TRIM protein family members. It consists of four zinc finger motifs in a B-box domain and a coiled-coil domain, and makes use of the B-box domain as E3 ubiquitin ligase in place of the RING. TRIM29 was found to be involved in the formation of homodimers and heterodimers in relation to DNA binding; additional studies have also demonstrated its role in carcinogenesis, DNA damage signaling, and the suppression of radiosensitivity. Recently, we reported that TRIM29 interacts with keratins and FAM83H to regulate keratin distribution. Further, in cutaneous SCC, the expression of TRIM29 is silenced by DNA methylation, leading to the loss of TRIM29 and promotion of keratinocyte migration. This paper reviews the role of TRIM family proteins in malignant tumors, especially the role of TRIM29 in cutaneous SCC.

Targeting Post-Translational Regulation of p53 in Colorectal Cancer by Exploiting Vulnerabilities in the p53-MDM2 Axis

The role played by the key tumor suppressor gene p53 and the implications of p53 mutations for the development and progression of neoplasia continue to expand. This review focuses on colorectal cancer and the regulators of p53 expression and activity identified over the past decade. These newly recognized regulatory mechanisms include (1) direct regulation of mouse double minute 2 homolog (MDM2), an E3 ubiquitin-protein ligase; (2) modulation of the MDM2-p53 interaction; (3) MDM2-independent p53 degradation; and (4) inhibition of p53 nuclear translocation. We positioned these regulatory mechanisms in the context of p53 missense mutations, which not only evade canonical p53 degradation machinery but also exhibit gain-of-function phenotypes that enhance tumor survival and metastasis. Lastly, we discuss current and potential therapeutic strategies directed against p53 mutant-bearing tumors.

Local non-pituitary growth hormone is induced with aging and facilitates epithelial damage

Microenvironmental factors modulating age-related DNA damage are unclear. Non-pituitary growth hormone (npGH) is induced in human colon, non-transformed human colon cells, and fibroblasts, and in 3-dimensional intestinal organoids with age-associated DNA damage. Autocrine/paracrine npGH suppresses p53 and attenuates DNA damage response (DDR) by inducing TRIM29 and reducing ATM phosphorylation, leading to reduced DNA repair and DNA damage accumulation. Organoids cultured up to 4 months exhibit aging markers, p16, and SA-β-galactosidase and decreased telomere length, as well as DNA damage accumulation, with increased npGH, suppressed p53, and attenuated DDR. Suppressing GH in aged organoids increases p53 and decreases DNA damage. WT mice exhibit age-dependent colon DNA damage accumulation, while in aged mice devoid of colon GH signaling, DNA damage remains low, with elevated p53. As age-associated npGH induction enables a pro-proliferative microenvironment, abrogating npGH signaling could be targeted as anti-aging therapy by impeding DNA damage and age-related pathologies.

Chesnokova et al. show that non-pituitary growth hormone (npGH) is induced in aging DNA-damaged colon epithelium and suppresses DNA damage response by attenuating the phosphorylation of DNA repair proteins. npGH induction promotes DNA damage accumulation, resulting in age-associated colon microenvironment changes. Accordingly, disrupted GH signaling in aging mice prevents accumulated DNA damage.

Dual Characters of GH-IGF1 Signaling Pathways in Radiotherapy and Post-radiotherapy Repair of Cancers

Radiotherapy remains one of the most important cancer treatment modalities. In the course of radiotherapy for tumor treatment, the incidental irradiation of adjacent tissues could not be completely avoided. DNA damage is one of the main factors of cell death caused by ionizing radiation, including single-strand (SSBs) and double-strand breaks (DSBs). The growth hormone-Insulin-like growth factor 1 (GH-IGF1) axis plays numerous roles in various systems by promoting cell proliferation and inhibiting apoptosis, supporting its effects in inducing the development of multiple cancers. Meanwhile, the GH-IGF1 signaling involved in DNA damage response (DDR) and DNA damage repair determines the radio-resistance of cancer cells subjected to radiotherapy and repair of adjacent tissues damaged by radiotherapy. In the present review, we firstly summarized the studies on GH-IGF1 signaling in the development of cancers. Then we discussed the adverse effect of GH-IGF1 signaling in radiotherapy to cancer cells and the favorable impact of GH-IGF1 signaling on radiation damage repair to adjacent tissues after irradiation. This review further summarized recent advances on research into the molecular mechanism of GH-IGF1 signaling pathway in these effects, expecting to specify the dual characters of GH-IGF1 signaling pathways in radiotherapy and post-radiotherapy repair of cancers, subsequently providing theoretical basis of their roles in increasing radiation sensitivity during cancer radiotherapy and repairing damage after radiotherapy.

TRIM29 Reverses Oxaliplatin Resistance of P53 Mutant Colon Cancer Cell

Background

Oxaliplatin is the first-choice chemotherapy method for patients with advanced colon cancer. However, its resistance leads to treatment failure for many patients. In our experiments, we aim to elucidate the associations among TRIM29 protein, mutant P53, and the resistance of colon cancer cells to oxaliplatin.

Methods

HCT116 and HT-29 cells were cultured and transfected with plasmids pIRES2-ZsGreen1-TRIM29-flag. Western blot and real-time qRT-PCR were utilized to examine the protein and mRNA expressions of TRIM29 and other related markers, respectively. MTT assay was utilized to determine the cell growth rate and generate the inhibition curve. Continuous culture in low-concentration oxaliplatin was conducted to construct oxaliplatin-resistant cell lines. The coimmunoprecipitation method and immunofluorescence detection were used to examine the interaction between TRIM29 and mutant P53 protein in HT29 cells.

Results

We successfully transfected pIRES2-ZsGreen1-TRIM29-flag into HCT116 and HT29 cells, which were utilized in the whole experiments. TRIM29 significantly increased the sensitivity of P53 mutant colon cancer cell HT29 to oxaliplatin. The oxaliplatin-resistant model of P53 mutant colon cancer cell HT29 was successfully constructed. TRIM29 physically bound with mutant P53 and retained it in the cytoplasm from the nucleus, which inhibited its transcription function of downstream genes such as MDR1. In addition, TRIM29 successfully reversed the resistance of HT29-OX resistant cell model to oxaliplatin.

Conclusion

In mutant P53 colon cancer cell HT29, TRIM29 greatly increased the sensitivity of HT29 to oxaliplatin and reverse oxaliplatin resistance. The underlying mechanism is TRIM29 may increase the sensitivity of HT29 to oxaliplatin by blocking the transcriptional function of mutant P53, which inhibits the transcription function of its downstream gene such as MDR1.

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.

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.

Nuclear Localization Is Not Required for Tip60 Tumor Suppressor Activity in Breast and Lung Cancer Cells

The Tip60 lysine acetyltransferase is a tumor suppressor in most cancers but an oncogene in prostate and gastric cancer. Tip60 is commonly found in the nucleus, where it acetylates proteins involved in transcription, DNA repair, and chromatin; however, it has also been shown to acetylate cytoplasmic targets. In this study, we investigated the relationship between Tip60 localization and breast and lung cancer. In cell fractionation experiments, cancer-derived cell lines showed a shift from nuclear to cytoplasmic endogenous Tip60 compared with cell lines derived from normal cells. With immunofluorescence, we observed four different localization patterns of overexpressed Tip60 and found that cancer cells had increased cytoplasmic localization of Tip60 compared with HEK-293 cells. The addition of a nuclear localization signal (NLS) increased the number of cells containing nuclear Tip60, whereas mutation of a putative endogenous NLS increased the number of cells with cytoplasmic Tip60. Overexpression of Tip60 increased cancer cell line sensitivity to paclitaxel regardless of changes in localization. These results suggest that dysregulation of Tip60 in breast and lung cancer is not limited to reduced expression but may also involve subcellular localization.

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.

TRIM29 is required for efficient recruitment of 53BP1 in response to DNA double-strand breaks in vertebrate cells

Tripartite motif‐containing protein 29 (TRIM29) is involved in DNA double‐strand break (DSB) repair. However, the specific roles of TRIM29 in DNA repair are not clearly understood. To investigate the involvement of TRIM29 in DNA DSB repair, we disrupted TRIM29 in DT40 cells by gene targeting with homologous recombination (HR). The roles of TRIM29 were investigated by clonogenic survival assays and immunofluorescence analyses. TRIM29 triallelic knockout (TRIM29^{−/−/−/+}) cells were sensitive to etoposide, but resistant to camptothecin. Foci formation assays to assess DNA repair activities showed that the dissociation of etoposide‐induced phosphorylated H2A histone family member X (ɣ‐H2AX) foci was retained in TRIM29^{−/−/−/+} cells, and the formation of etoposide‐induced tumor suppressor p53‐binding protein 1 (53BP1) foci in TRIM29^{−/−/−/+} cells was slower compared with wild‐type (WT) cells. Interestingly, the kinetics of camptothecin‐induced RAD51 foci formation of TRIM29^{−/−/−/+} cells was higher than that of WT cells. These results indicate that TRIM29 is required for efficient recruitment of 53BP1 to facilitate the nonhomologous end‐joining (NHEJ) pathway and thereby suppress the HR pathway in response to DNA DSBs. TRIM29 regulates the choice of DNA DSB repair pathway by facilitating 53BP1 accumulation to promote NHEJ and may have potential for development into a therapeutic target to sensitize refractory cancers or as biomarker of personalized therapies.

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.

Actin‑like protein 8 executes a promoting function in the malignant progression of endometrial cancer: identification of a promising biomarker

Endometrial cancer (EC) is generally considered as a disease that affects older women. We attempt to explore the role of actin‑like protein 8 (ACTL8) in EC and how it achieves its function. Based on the data from The Cancer Genome Atlas (TCGA), we found that ACTL8 expression was up-regulated in EC tissues and correlated with shorter overall survival of EC patients. ACTL8 expression was significantly associated with age, clinical-stage, or grade. Cox proportional hazards model analysis revealed that ACTL8 expression, grade, and clinical-stage were promising independent prognostic factors of EC. Knockdown of ACTL8 repressed the proliferative, migrating and invading capabilities of human EC cell lines KLE and Ishikawa. Silencing ACTL8 up-regulated the negative cell cycle regulator p21 and epithelial marker E-cadherin, and down-regulated the positive cell cycle regulator Cyclin A, mesenchymal markers MMP-9 and N-cadherin in KLE cells. Collectively, these outcomes illustrated that ACTL8 might act as a tumor facilitator during EC progression.

Regulation of the p53 Family Proteins by the Ubiquitin Proteasomal Pathway

The tumor suppressor p53 and its homologues, p63 and p73, play a pivotal role in the regulation of the DNA damage response, cellular homeostasis, development, aging, and metabolism. A number of mouse studies have shown that a genetic defect in the p53 family could lead to spontaneous tumor development, embryonic lethality, or severe tissue abnormality, indicating that the activity of the p53 family must be tightly regulated to maintain normal cellular functions. While the p53 family members are regulated at the level of gene expression as well as post-translational modification, they are also controlled at the level of protein stability through the ubiquitin proteasomal pathway. Over the last 20 years, many ubiquitin E3 ligases have been discovered that directly promote protein degradation of p53, p63, and p73 in vitro and in vivo. Here, we provide an overview of such E3 ligases and discuss their roles and functions.

ATDC promotes the growth and invasion of hepatocellular carcinoma cells by modulating GSK-3β/Wnt/β-catenin signalling

Accumulating evidence has suggested that the ataxia telangiectasia group D complementing (ATDC) gene is an emerging cancer-related gene in multiple human cancer types. However, little is known about the role of ATDC in hepatocellular carcinoma (HCC). In this study, we aimed to investigate the expression level, biological function and underlying mechanism of ATDC in HCC. The expression of ATDC in HCC cells was detected by quantitative real-time polymerase chain reaction and western blot analysis. Cell growth was determined by cell counting kit-8 assay and colony formation assay. Cell invasion was assessed by Transwell invasion assay. The activation status of Wnt/β-catenin signalling was evaluated by the luciferase reporter assay. Functional experiments showed that the silencing of ATDC expression significantly suppressed the growth and invasion of HCC cells, whereas the overexpression of ATDC promoted the growth and invasion of HCC cells in vitro. Moreover, we showed that ATDC overexpression promoted the phosphorylation of glycogen synthase kinase (GSK)-3β and resulted in the activation of Wnt/β-catenin signalling. Notably, the inhibition of GSK-3β activity significantly abrogated the tumour suppressive effect of ATDC silencing, while the silencing of β-catenin partially reversed the oncogenic effect of ATDC overexpression. Taken together, these findings reveal an oncogenic role of ATDC in HCC and show that the suppression of ATDC impedes the growth and invasion of HCC cells associated with the inactivation of Wnt/β-catenin signalling. Our study suggests that ATDC may serve as a potential therapeutic target for HCC.

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.

Excess growth hormone suppresses DNA damage repair in epithelial cells

Growth hormone (GH) decreases with age, and GH therapy has been advocated by some to sustain lean muscle mass and vigor in aging patients and advocated by athletes to enhance performance. Environmental insults and aging lead to DNA damage, which - if unrepaired - results in chromosomal instability and tumorigenesis. We show that GH suppresses epithelial DNA damage repair and blocks ataxia telangiectasia mutated (ATM) kinase autophosphorylation with decreased activity. Decreased phosphorylation of ATM target proteins p53, checkpoint kinase 2 (Chk2), and histone 2A variant led to decreased DNA repair by nonhomologous end-joining. In vivo, prolonged high GH levels resulted in a 60% increase in unrepaired colon epithelial DNA damage. GH suppression of ATM was mediated by induced tripartite motif containing protein 29 (TRIM29) and attenuated tat interacting protein 60 kDa (Tip60). By contrast, DNA repair was increased in human nontumorous colon cells (hNCC) where GH receptor (GHR) was stably suppressed and in colon tissue derived from GHR-/- mice. hNCC treated with etoposide and GH showed enhanced transformation, as evidenced by increased growth in soft agar. In mice bearing human colon GH-secreting xenografts, metastatic lesions were increased. The results elucidate a mechanism underlying GH-activated epithelial cell transformation and highlight an adverse risk for inappropriate adult GH treatment.

Tripartite motif-containing 15 overexpression in non-small cell lung cancer is associated with poor patient prognoses

Purpose: This study aimed to comprehensively investigate the differential expression and prognostic indicators of the tripartite motif-containing (TRIM) gene family in non-small cell lung cancer (NSCLC). Methods: The Cancer Genome Atlas (TCGA) Research Network and three datasets from Gene Expression Omnibus (GEO) database were used to assess TRIM gene family expression patterns in NSCLC. Quantitative real-time PCR and immunohistochemistry (IHC) were conducted to confirm differentially expressed genes (DEGs). Kaplan-Meier survival analysis and univariate Cox regression analysis were carried out to analyze the association between TRIM gene expression and NSCLC prognoses. Gene set enrichment analysis (GSEA) was carried on for the predict the biological processes. Results: Of the 78 TRIM family members measured, TRIM15 was selected due to the DEGs and the prognostic value regarding NSCLC. In lung squamous cell carcinoma (LUSC), the Log₂ fold change (Log₂FC) of TRIM15 was 5.16 (p= 0.00575), whereas in lung adenocarcinoma (LUAD), it was 6.37 (p =6.78E-07). TRIM15 upregulation was related to poor prognoses in both LUSC (HR 1.353; 95%CI 1.023-1.789; p =0.034) and LUAD (HR 1.560; 95%CI 1.159-2.101; p =0.003). Using immunohistochemistry, TRIM15 expression was significantly higher in NSCLC tissues compared with that of matched normal tissues (p =0.0009), and similar findings were generated with tissue microarray analysis (p<0.0001). Conclusion: TRIM15 could act as a diagnostic predictor or therapeutic target for lung cancer treatments.

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.

Loss of TRIM29 Alters Keratin Distribution to Promote Cell Invasion in Squamous Cell Carcinoma

: TRIM29 (tripartite motif-containing protein 29) is a TRIM family protein that has been implicated in breast, colorectal, and pancreatic cancers. However, its role in stratified squamous epithelial cells and tumors has not been elucidated. Here, we investigate the expression of TRIM29 in cutaneous head and neck squamous cell carcinomas (SCC) and its functions in the tumorigenesis of such cancers. TRIM29 expression was lower in malignant SCC lesions than in adjacent normal epithelial tissue or benign tumors. Lower expression of TRIM29 was associated with higher SCC invasiveness. Primary tumors of cutaneous SCC showed aberrant hypermethylation of TRIM29. Depletion of TRIM29 increased cancer cell migration and invasion; conversely, overexpression of TRIM29 suppressed these. Comprehensive proteomics and immunoprecipitation analyses identified keratins and keratin-interacting protein FAM83H as TRIM29 interactors. Knockdown of TRIM29 led to ectopic keratin localization of keratinocytes. In primary tumors, lower TRIM29 expression correlated with the altered expression of keratins. Our findings reveal an unexpected role for TRIM29 in regulating the distribution of keratins, as well as in the migration and invasion of SCC. They also suggest that the TRIM29-keratin axis could serve as a diagnostic and prognostic marker in stratified epithelial tumors and may provide a target for SCC therapeutics. SIGNIFICANCE: These findings identify TRIM29 as a novel diagnostic and prognostic marker in stratified epithelial tissues.

The Mutant p53-Targeting Compound APR-246 Induces ROS-Modulating Genes in Breast Cancer Cells

TP53 is the most frequently mutated gene in human cancer and thus an attractive target for novel cancer therapy. Several compounds that can reactive mutant p53 protein have been identified. APR-246 is currently being tested in a phase II clinical trial in high-grade serous ovarian cancer. We have used RNA-seq analysis to study the effects of APR-246 on gene expression in human breast cancer cell lines. Although the effect of APR-246 on gene expression was largely cell line dependent, six genes were upregulated across all three cell lines studied, i.e., TRIM16, SLC7A11, TXNRD1, SRXN1, LOC344887, and SLC7A11-AS1. We did not detect upregulation of canonical p53 target genes such as CDKN1A (p21), 14-3-3σ, BBC3 (PUMA), and PMAIP1 (NOXA) by RNA-seq, but these genes were induced according to analysis by qPCR. Gene ontology analysis showed that APR-246 induced changes in pathways such as response to oxidative stress, gene expression, cell proliferation, response to nitrosative stress, and the glutathione biosynthesis process. Our results are consistent with the dual action of APR-246, i.e., reactivation of mutant p53 and modulation of redox activity. SLC7A11, TRIM16, TXNRD1, and SRXN1 are potential new pharmacodynamic biomarkers for assessing the response to APR-246 in both preclinical and clinical studies.

The post-translational modification, SUMOylation, and cancer (Review)

SUMOylation is a reversible post-translational modification which has emerged as a crucial molecular regulatory mechanism, involved in the regulation of DNA damage repair, immune responses, carcinogenesis, cell cycle progression and apoptosis. Four SUMO isoforms have been identified, which are SUMO1, SUMO2/3 and SUMO4. The small ubiquitin-like modifier (SUMO) pathway is conserved in all eukaryotes and plays pivotal roles in the regulation of gene expression, cellular signaling and the maintenance of genomic integrity. The SUMO catalytic cycle includes maturation, activation, conjugation, ligation and de-modification. The dysregulation of the SUMO system is associated with a number of diseases, particularly cancer. SUMOylation is widely involved in carcinogenesis, DNA damage response, cancer cell proliferation, metastasis and apoptosis. SUMO can be used as a potential therapeutic target for cancer. In this review, we briefly outline the basic concepts of the SUMO system and summarize the involvement of SUMO proteins in cancer cells in order to better understand the role of SUMO in human disease.

TRIM29 as a prognostic predictor for multiple human malignant neoplasms: a systematic review and meta-analysis

Recent studies have shown that tripartite motif-containing protein 29 (TRIM29) had prognostic values in several cancers. However, different studies have been inconsistent. We conducted a meta-analysis to elucidate the precise predictive value of TRIM29 in various human malignant disease. Eleven eligible studies with 2046 patients were ultimately enrolled in this meta-analysis. Heterogeneity between studies was assessed using I² statistics. Pooled Hazard ratios (HRs) with 95% confidence intervals (CIs) for patient survival and disease recurrence were calculated to investigate the correlation between TRIM29 expression and cancer prognosis. The results identified an important link between upregulated TRIM29 expression and poor prognosis in patients with multiple human malignant neoplasms in terms of recurrence-free survival (RFS)/disease-free survival (DFS) (HR = 1.66, 95% CI 1.36–2.04) but favorable progression-free survival (PFS)/metastasis-free survival (MFS) (HR = 0.37, 95% CI 0.16–0.85). We found that high TRIM29 expression predicted no significant impact on overall survival (OS) (HR = 1.32, 95% CI 0.90–1.93). Subgroup analyses showed that high TRIM29 expression predicted poor OS in Asians (HR = 2.21, 95% CI 1.78–2.74) but favorable OS in Caucasian (HR = 0.47, 95% CI 0.25–0.89). TRIM29 might play an essential role in carcinogenesis of multiple human malignant neoplasms and could serve as a biomarker for the prediction of patients’ prognosis.

MRGBP as a potential biomarker for the malignancy of pancreatic ductal adenocarcinoma

MORF4-related gene-binding protein (MRGBP), which is also known as chromosome 20 open reading frame 20 (C20orf20), is commonly highly expressed in several types of malignant tumors and tumor progression. However, the expression pattern and underlying mechanism of MRGBP in pancreatic ductal adenocarcinoma (PDAC) remain unknown. In the study, we found that MRGBP was frequently upregulated in PDAC tissues and cell lines. In addition, the upregulation of MRGBP was positively associated with TNM stage, T classification, and poor prognosis. Knockdown of MRGBP in the PDAC cell lines ASPC-1 and Mia PaCa-2 by transiently transfected with small interfering RNA (siRNA) drastically attenuated the proliferation, migration, and invasion of those cells, whereas ectopic MRGBP overexpression in BxPC-3 cells produced exactly the opposite effect. Furthermore, we also found that overexpression of MRGBP remarkably led to cell morphological changes and induced an increased expression of mesenchymal marker Vimentin, whereas a decreased expression of epithelial marker E-cadherin. Taken together, this study indicates that MRGBP acts as a tumor oncogene in PDAC and is a promising target of carcinogenesis.

High expression of TRIM29 (ATDC) contributes to poor prognosis and tumor metastasis by inducing epithelial‑mesenchymal transition in osteosarcoma

The association of TRIM29 overexpression with cancer progression and poor clinical prognosis has been reported in the context of several types of cancers. In the present study, we investigated the prognostic relevance of TRIM29 and its involvement in the progression of human osteosarcoma. To the best of our knowledge, this is the first study to demonstrate a major role of TRIM29 in osteosarcoma. Our results showed that the expression of TRIM29 in osteosarcoma tissues was much higher than that in normal bone tissues. Furthermore, TRIM29 expression was significantly correlated with tumor size, recurrence, metastasis and overall survival time. High expression of TRIM29 and presence of metastasis were independent predictors of poor prognosis in these patients. Both protein and mRNA expression of TRIM29 in osteosarcoma cell lines were significantly higher than those in osteoblast cell line, hFOB1.19. Moreover, the results indicated that TRIM29 promoted migration and invasive growth of osteosarcoma cells by inducing epithelial-mesenchymal transition. Therefore, ectopic expression of TRIM29 potentially contributes to metastasis and poor prognosis in patients with osteosarcoma. In summary, TRIM29 is a potential prognostic biomarker and a therapeutic target for patients with osteosarcoma.

Lentivirus-mediated RNA interference of tripartite motif 68 inhibits the proliferation of colorectal cancer cell lines SW1116 and HCT116 in vitro

Colorectal cancer is one of the most common types of cancer worldwide. Previous studies have revealed that certain members of tripartite motif (TRIM) proteins are involved in carcin ogenesis regulation, but little is known about the function of TRIM68 in human colorectal cancer. To investigate the role of TRIM68 in colorectal cancer SW1116 and HCT116 cell lines, the present study conducted lentivirus-mediated knockdown against TRIM68 and demonstrated that depletion of TRIM68 notably inhibits colorectal cancer cell proliferation and colony formation ability. Cell cycle arrest in the G0/G1 phase and cycle accumulation in sub-G1 phase provided evidence that TRIM68 may participate in the regulation of colorectal cancer tumorigenesis. The results revealed the significant role of TRIM68 in regulating colorectal cancer cell mitosis and indicated that TRIM68 may be a promising therapeutic target.

Essential Roles of E3 Ubiquitin Ligases in p53 Regulation

The ubiquitination pathway and proteasomal degradation machinery dominantly regulate p53 tumor suppressor protein stability, localization, and functions in both normal and cancerous cells. Selective E3 ubiquitin ligases dominantly regulate protein levels and activities of p53 in a large range of physiological conditions and in response to cellular changes induced by exogenous and endogenous stresses. The regulation of p53’s functions by E3 ubiquitin ligases is a complex process that can lead to positive or negative regulation of p53 protein in a context- and cell type-dependent manner. Accessory proteins bind and modulate E3 ubiquitin ligases, adding yet another layer of regulatory control for p53 and its downstream functions. This review provides a comprehensive understanding of p53 regulation by selective E3 ubiquitin ligases and their potential to be considered as a new class of biomarkers and therapeutic targets in diverse types of cancers.

TRIM14 is a Putative Tumor Suppressor and Regulator of Innate Immune Response in Non-Small Cell Lung Cancer

Non-small-cell lung carcinoma (NSCLC) accounts for 85% of malignant lung tumors and is the leading cause of cancer deaths. Our group previously identified Tripartite Motif 14 (TRIM14) as a component of a prognostic multigene expression signature for NSCLC. Little is known about the function of TRIM14 protein in normal or disease states. We investigated the functional and prognostic role of TRIM14 in NSCLC using in vitro and in vivo perturbation model systems. Firstly, a pooled RNAi screen identified TRIM14 to effect cell proliferation/survival in NSCLC cells. Secondly, silencing of TRIM14 expression significantly enhanced tumor growth in NSCLC xenograft mouse models, while exogenous TRIM14 expression attenuated tumorigenesis. In addition, differences in apoptotic activity between TRIM14-deficient and control tumors suggests that TRIM14 tumor suppressor activity may depend on cell death signaling pathways. TRIM14-deficient cell lines showed both resistance to hypoxia-induced cell death and attenuation of interferon response via STAT1 signaling. Consistent with these phenotypes, multivariate analyses on published mRNA expression datasets of over 600 primary NSCLCs demonstrated that low TRIM14 mRNA levels are significantly associated with poorer prognosis in early stage NSCLC patients. Our functional data therefore establish a novel tumor suppressive role for TRIM14 in NSCLC progression.

TRIM14 Inhibits cGAS Degradation Mediated by Selective Autophagy Receptor p62 to Promote Innate Immune Responses

Cyclic GMP-AMP synthase (cGAS) is an essential DNA virus sensor that triggers type I interferon (IFN) signaling by producing cGAMP to initiate antiviral immunity. However, post-translational regulation of cGAS remains largely unknown. We report that K48-linked ubiquitination of cGAS is a recognition signal for p62-depdendent selective autophagic degradation. The induction of TRIM14 by type I IFN accelerates cGAS stabilization by recruiting USP14 to cleave the ubiquitin chains of cGAS at lysine (K) 414. Knockout of TRIM14 impairs herpes simplex virus type 1 (HSV-1)-triggered antiviral responses in a cGAS-dependent manner. Due to impaired type I IFN production, Trim14^-/- mice are highly susceptible to lethal HSV-1 infection. Taken together, our findings reveal a positive feedback loop of cGAS signaling generated by TRIM14-USP14 and provide insights into the crosstalk between autophagy and type I IFN signaling in innate immunity.

RNA interference against TRIM29 inhibits migration and invasion of colorectal cancer cells

Colorectal cancer (CRC) is one of the most common malignancies worldwide. Tripartite motif-containing 29 (TRIM29) is a member of TRIM proteins family, which plays diverse physiological and pathological roles in humans. Recent studies found that TRIM29 expressed highly in CRC and promoted cell growth in vitro. However, its function in the metastasis of CRC has not been studied. In the present study, we confirmed the previous report that TRIM29 was upregulated in CRC tissues and high levels of TRIM29 expression were associated with poor overall survival of patients. Moreover, TRIM29 knockdown significantly reduced cancer cell proliferation via notably inducing cell cycle arrest and cell apoptosis. Silencing of TRIM29 significantly inhibited the migration and invasion ability of CRC cells. The protein levels of apoptosis‑, migration‑ and invasion‑related proteins were also changed after TRIM29 knockdown. Furthermore, phosphorylation levels of JAK2 and STAT3 were clearly reduced in TRIM29 knockdown cells, indicating a possible mechanism underlying its effects on colorectal carcinogenesis. Collectively, TRIM29 may exert oncogenic effects in CRC cells via regulating JAK2/STAT3 signaling.

Upregulated TRIM29 promotes proliferation and metastasis of nasopharyngeal carcinoma via PTEN/AKT/mTOR signal pathway

Tripartite motif-containing 29 (TRIM29) has been reported to be dysregulated in human cancers. Up-regulation of TRIM29 was first observed in NPC cell lines by a genome-wide transcriptome analysis in our previous study. However, its expression biological function and clinical significance in nasopharyngeal carcinoma (NPC) remain unclear. In this study, TRIM29 expression was validated by qRT-PCR and immunohistochemistry in 69 NPC samples. Notably, TRIM29 protein expression was significantly and positively correlated with the tumor size, clinical stage and metastasis. TRIM29 was identified as the direct target of miR-335-5p and miR-15b-5p, both of which were down-regulated and negatively associated with TRIM29 expression in NPC cell lines and clinical samples. Ectopic TRIM29 expression promoted proliferation, epithelial-mesenchymal transition (EMT), migration and invasion in NPC cells, while its depletion inhibited cell invasion and EMT phenotype. Mechanistically, TRIM29 overexpression reduced PTEN expression and increase phosphorylated protein level of AKT, p70S6K and 4E-BP1. Correspondingly, AKT inhibitor and Rapamycin blocked the effect of TRIM29 on cell invasion. In conclusion, our results suggest that miR-335-5p and miR-15b-5p down-regulation results in TRIM29 over-expression, which induces proliferation, EMT and metastasis of NPC through the PTEN/AKT/mTOR signaling pathway.

TRIMming p53's anticancer activity

Several TRIM proteins control abundance and activity of p53. Along this route, TRIM proteins have a serious impact on carcinogenesis and prognosis for cancer patients. In the past years, a significant increase has been made in our understanding of how the TRIM protein family controls p53 activity.