TRIM66 expression in non-small cell lung cancer: A new predictor of prognosis

Tripartite motif family - its role in tumor progression and therapy resistance: a review

PURPOSE OF REVIEW

In this review, we summarized published articles on the role of tripartite motif (TRIM) family members in the initiation and development of human malignancies.

RECENT FINDINGS

The ubiquitin-proteasome system (UP-S) plays a critical role in cellular activities, and UP-S dysregulation contributes to tumorigenesis. One of the key regulators of the UP-S is the tripartite motif TRIM protein family, most of which are active E3 ubiquitin ligases. TRIM proteins are critical for the biological functions of cancer cells, including migration, invasion, metastasis, and therapy resistance. Therefore, it is important to understand how TRIM proteins function at the molecular level in cancer cells.

SUMMARY

We provide a comprehensive and up-to-date overview about the role TRIMs play in cancer progression and therapy resistance. We propose TRIM family members as potential new markers and targets to overcome therapy failure.

Circ-SATB2 (hsa_circ_0008928) and miR-150-5p are regulators of TRIM66 in the regulation of NSCLC cell growth and metastasis of NSCLC cells via the ceRNA pathway

Circular RNA (circRNA) was an important modulator and potential molecular target of nonsmall cell lung cancer (NSCLC). CircSATB2 was reported to be upregulated in NSCLC. However, the role and mechanism of circSATB2 in NSCLC progression remain to be illustrated. The RNA and protein expression was detected by quantitative real-time polymerase chain reaction, western blot, and immunohistochemistry assay. Cell counting kit-8, cell colony formation, and 5-ethynyl-2'-deoxyuridine assays were applied to assess cell growth. The migrated and invaded cells were examined by transwell assay. Flow cytometry was performed to measure apoptotic cells. The interaction among circSATB2, microRNA-150-5p (miR-150-5p), and tripartite motif-containing protein 66 (TRIM66) was identified by dual-luciferase reporter assay and RNA immunoprecipitation assay. An in vivo experiment was conducted to investigate the effect of circSATB2 on tumor growth. CircSATB2 expression was highly expressed in NSCLC tissues and cell lines. CircSATB2 and TRIM66 silencing both suppressed NSCLC cell growth, migration, and invasion whereas promoted NSCLC cell apoptosis. CircSATB2 acted as a molecular sponge for miR-150-5p, and miR-150-5p interacted with the 3' untranslated region (3'UTR) of TRIM66. Moreover, circSATB2 knockdown-induced effects were partly reversed by TRIM66 overexpression in NSCLC cells. Besides, cirSATB2 expression was negatively correlated with miR-150-5p level and positively correlated with TRIM66 level in NSCLC tumor tissues. CircSATB2 knockdown blocked xenograft tumor growth in vivo. In summary, this study verified that circSATB2 stimulated NSCLC cell malignant behaviors by miR-150-5p/TRIM66 pathway, providing a possible circRNA-targeted therapy for NSCLC.

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.

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.

TRIM66 Promotes Malignant Progression of Non-Small-Cell Lung Cancer Cells via Targeting MMP9

Lung cancer has a higher incidence and mortality rate than other cancers, and over 80% of lung cancer cases were classified as non-small-cell lung cancer (NSCLC). TRIM66 is one of the crucial members of TRIM, which has a deep connection with the behavior of various malignant tumors. But it remains uncertain regarding its exact function and underlying mechanism in NSCLC. In our study, qRT-PCR and Western blot were employed to validate that TRIM66 was overexpressed in NSCLC. The migration, invasion, and epithelial-mesenchymal transformation (EMT) progression of NSCLC cells were determined by Western blotting and Transwell experiments after knocking down TRIM66, and it was found that knockdown TRIM66 inhibited the migration, invasion, and EMT processes of NSCLC cells. Next, the binding relationship between TRIM66 and MMP9 was verified by Co-IP assay. After determining the interaction between them, rescue assays showed that overexpression of MMP9 was capable to promote the migration, invasion, and EMT of NSCLC cells. However, the transfection of si-TRIM66 could reverse this facilitating effectiveness. To sum up, we concluded that by targeting MMP9, TRIM66 could exert a cancer-promoting role in the progression of NSCLC cells.

TRIM66 Overexpression Promotes Glioma Progression and Regulates Glucose Uptake Through cMyc/GLUT3 Signaling

OBJECTIVE

Tripartite motif 66 (TRIM66) is reported to be closely associated with human cancers. However, the roles of TRIM66 in glioma remain unclear. The present study aimed to investigate the clinical significance and biological roles of TRIM66 in human glioma.

METHODS

TRIM66 expression in glioma tissues was examined by immunohistochemistry. TRIM66 overexpression and siRNA knockdown were performed in glioblastoma cell lines. CCK8, colony formation assay, transwell assay, Annexin V and JC1 staining, glucose uptake assay, and Western blotting were used to explore the biological roles and potential underlying mechanisms of TRIM66 in glioma progression.

RESULTS

Our results showed that TRIM66 was overexpressed in 52/95 glioma cases. The rates of TRIM66 overexpression in Grade I, Grade II, Grade III, and Grade IV gliomas were 16.6%, 41.3%, 58.6%, and 70.9%, respectively. Oncomine data showed that TRIM66 was upregulated in glioblastoma and oligodendroglioma compared with normal brain tissues. TRIM66 expression was higher in glioblastoma cell lines compared with normal SVG p12 glial cell line. TRIM66 promoted in vitro and in vivo proliferation, invasion, and inhibited temozolomide (TMZ)-induced apoptosis. Notably, TRIM66 increased glucose metabolism by upregulating glucose uptake, glucose consumption, and ATP production. Western blotting showed that TRIM66 positively regulated cMyc and GLUT3. Depletion of cMyc by siRNA abolished the effect of TRIM66 on GLUT3. Chromatin immunoprecipitation (ChIP) assay showed that cMyc could bind to the promoter regions of GLUT3 in glioblastoma cells.

CONCLUSION

TRIM66 was upregulated in human gliomas, where it promoted cell growth and chemoresistance. Our data also identified novel roles of TRIM66 in glioma progression. TRIM66 upregulates glucose uptake and mitochondrial function through the cMyc/GLUT3 signaling, which makes it a potential therapeutic target.

Qi Ling Inhibits Progression of Androgen-Independent Prostate Cancer via Negative Regulation of TRIM66/HP1γ/AR Axis

AIM

This study aimed to understand the molecular mechanism underlying the therapeutic effect of Qi Ling (QL) against androgen-independent prostate cancer.

METHODS

The relative expression of TRIM66 in prostate tumor was interrogated by microarray. Real-time polymerase chain reaction and Western blotting were performed to determine the transcript abundances and protein expressions of TRIM66, HP1γ, AR, c-Myc, and GAPDH. Cell proliferation and apoptosis were analyzed by cell counting kit-8 method and flow cytometry. The regulatory action of c-Myc on TRIM66 was interrogated with luciferase reporter plasmid and the direct binding was demonstrated by chromatin immunoprecipitation. The secretory prostate-specific antigen was quantified by enzyme-linked immunosorbent assay.

RESULTS

TRIM66 was aberrantly overexpressed in prostate cancer and associated with unfavorable prognosis. TRIM66/HP1γ/AR was upregulated during the androgen-independent transition in hormone-deprived medium. The TRIM66 level positively linked to cell proliferation and negatively linked to cell apoptosis in androgen-independent prostate cancer cells. QL treatment specifically inhibited c-Myc and therefore directly downregulated TRIM66 via binding to its promoter. Ectopic introduction of TRIM66 significantly reversed the anti-tumor effects of QL against androgen-independent prostate cancer.

CONCLUSION

Our study uncovered the importance of downregulated TRIM66/HP1γ/AR signaling in mediating the anti-tumor properties of QL.

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.

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.

TIF1 Proteins in Genome Stability and Cancer

Genomic instability is a hallmark of cancer cells which results in excessive DNA damage. To counteract this, cells have evolved a tightly regulated DNA damage response (DDR) to rapidly sense DNA damage and promote its repair whilst halting cell cycle progression. The DDR functions predominantly within the context of chromatin and requires the action of chromatin-binding proteins to coordinate the appropriate response. TRIM24, TRIM28, TRIM33 and TRIM66 make up the transcriptional intermediary factor 1 (TIF1) family of chromatin-binding proteins, a subfamily of the large tripartite motif (TRIM) family of E3 ligases. All four TIF1 proteins are aberrantly expressed across numerous cancer types, and increasing evidence suggests that TIF1 family members can function to maintain genome stability by mediating chromatin-based responses to DNA damage. This review provides an overview of the TIF1 family in cancer, focusing on their roles in DNA repair, chromatin regulation and cell cycle regulation.

miR-451a Inhibits the Growth and Invasion of Osteosarcoma via Targeting TRIM66

The importance of microRNAs in regulating osteosarcoma development has been studied in recent years. However, the function of microRNA-451a in osteosarcoma growth is rarely investigated. Here, we explored the expression of microRNA-451a in osteosarcoma cell lines. Bioinformatic software, luciferase activity reporter assay, and Western blot were conducted to determine the association between microRNA-451a and tripartite motif-containing 66. Cell Counting Kit-8 assay and transwell assay were used to explore the regulatory effects of microRNA-451a on osteosarcoma cells. Moreover, we explored whether microRNA-451a modulates osteosarcoma cell biological activity by regulating tripartite motif-containing 66. The expression of microRNA-451a was found to be downregulated in osteosarcoma and negatively regulated the expression of tripartite motif-containing 66. Tripartite motif-containing 66 was further validated as a target of microRNA-451a. MicroRNA-451a inhibits the growth and invasion of osteosarcoma cell lines through targeting tripartite motif-containing 66. The miR-451a targets tripartite motif-containing 66 may provide novel therapeutic targets for the treatment of osteosarcoma.

Knockdown of TRIM66 inhibits cell proliferation, migration and invasion in colorectal cancer through JAK2/STAT3 pathway

Colorectal cancer (CRC) is one of the most common malignancies in the world. Emerging evidence has shown that dysregulation of tripartite motif (TRIM) family proteins is strongly correlated with the tumorigenesis of CRC. Here, we evaluated the biological roles of TRIM66, a member of TRIM family, in the progression of CRC. The results demonstrated that TRIM66 was markedly up-regulated in both CRC tissues and cell lines. To further investigate the functions of TRIM66 in CRC, CRC cells were infected with lentivirus expressing anti-TRIM66 shRNA (sh-TRIM66) or control lentivirus (sh-con). We found that knockdown of TRIM66 significantly inhibited cell proliferation, migration, invasion of CRC cells. TRIM66 knockdown also suppressed epithelial-mesenchymal transition (EMT), as proved by the increased E-cadherin expression and decreased expressions of N-cadherin and vimentin. Furthermore, TRIM66 knockdown markedly inhibited tumor growth in a mouse xenograft model. Knockdown of TRIM66 reduced the activation of JAK2/STAT3 signaling pathway in CRC cells. Treatment with AG490, an inhibitor of JAK2/STAT3 signaling pathway, enhanced the inhibitory effects of TRIM66 knockdown on cell proliferation, migration and invasion. These findings suggested that knockdown of TRIM66 exhibited anti-tumor activity through inhibiting the JAK2/STAT3 signaling pathway in CRC cells.

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.

TRIM66 confers tumorigenicity of hepatocellular carcinoma cells by regulating GSK-3β-dependent Wnt/β-catenin signaling

Tripartite motif 66 (TRIM66) protein, a member of the tripartite motif (TRIM) protein superfamily, has emerged as an oncogenic protein that is closely related to carcinogenesis in multiple cancers. However, whether TRIM66 plays a role in the progression of hepatocellular carcinoma (HCC) remains unknown. This study was aimed to investigate TRIM66 expression and its potential biological function in HCC cell lines. Here we showed that TRIM66 expression was significantly upregulated in HCC cell lines compared with normal control cells. Loss-of-function experiments by RNA interfering knockdown of TRIM66 showed that TRIM66 inhibition significantly reduced the proliferation, colony formation, and invasion of HCC cells, whereas gain-of-function by overexpression of TRIM66 exhibited the opposite effect. Further investigation showed that TRIM66 was involved in regulating glycogen synthase kinase-3β (GSK-3β) phosphorylation and β-catenin expression. Knockdown of TRIM66 impeded the activation of Wnt signaling, while overexpression of TRIM66 promoted Wnt signaling activation. Moreover, inhibition of GSK-3β by specific inhibitor partially reversed TRIM66 inhibition-mediated antitumor effect, while knockdown of β-catenin blocked the oncogenic effect of TRIM66 overexpression in HCC cells. Additionally, in vivo experiments using a xenograft tumor model showed that TRIM66 knockdown blunted the tumorigenicity of HCC cells associated with downregulation of β-catenin expression. Overall, our results showed that TRIM66 functioned as an oncogenic protein in HCC by promoting the activation of Wnt/β-catenin signaling. Our study suggests that TRIM66 is a potential target for HCC treatment.

LncRNA TATDN1 contributes to the cisplatin resistance of non-small cell lung cancer through TATDN1/miR-451/TRIM66 axis

BACKGROUND

Chemoresistance has been considered to be a major obstacle for cancer therapy clinically. Long non-coding RNAs (LncRNAs) are asscociated with the development, prognosis and drug-resistance of non-small cell lung cancer (NSCLC). Whereas, the regulatory mechanism of lncRNA TATDN1 in the cisplatin resistance of NSCLC is still not clear.

METHODS

The expression of TATDN1, miR-451 and TRIM66 in NSCLC tissues and cell lines were detected by qRT-PCR or western blot. Immunohistochemistry (IHC) assay was performed for the detection of TATDN1 expression profile. 88 patients who underwent cisplatin treatment were followed up to 60-months for the analysis of survival rate. MTT and Flow cytometry analysis were performed for the assessment of cell survival rate, proliferation and apoptosis. Bioinformatics, Dual-Luciferase reporter were employed to analyze the interaction among TATDN1, miR-451 and TRIM66. Xenograft tumor model was constructed to verify the role of TATDN1 in NSCLC treated with cisplatin (DDP) in vivo.

RESULTS

TATDN1 and TRIM66 was significantly upregulated while miR-451 was downregulated in NSCLC tissues and cell lines, especially in DDP-resistant tumor tissues and cells. Survival rates of NSCLC patients with low TATDN1 expression were improved following DDP chemotherapy. TATDN1 upregulated TRIM66 expression via sponge for miR-451. Moreover, TATDN1 knockdown improved DDP-sensitivity in NSCLC patients by regulation of miR-451/TRIM66 axis. Finally, knockdown of TATDN1 improved the sensitivity of NSCLC to DDP in vivo.

CONCLUSIONS

TATDN1 enhanced the DDP-tolerance of NSCLC cells by upregulating TRIM66 expression via sponging miR-451, hinting a novel regulatory pathway of chemoresistance in DDP-tolerant NSCLC cells and providing a potential therapeutic target for NSCLC patients with DDP-reistance.

Knockdown of TRIM66 inhibits malignant behavior and epithelial-mesenchymal transition in non-small cell lung cancer

OBJECTIVE

The tripartite motif 66(TRIM66) is an important member of the TRIM protein superfamily, which can participate in the expression of multiple proteins, and is closely associated with the behaviors of non-small cell lung cancer (NSCLC). In this study, we aimed to explore the effect of TRIM66 in this process in vitro using NSCLC cell lines, and the role of TRIM66 in regulating epithelial-mesenchymal transition(EMT) in NSCLC.

METHODS

Western blotting was used to detect the TRIM66 protein expression levels in NSCLC cell lines and normal lung epithelial cells BEAS-2B. We silenced its expression in A549 cells by transient siRNA transfection to ascertain the function of TRIM66 in NSCLC cells. Western blotting was used to detect the expression of EMT-related proteins.

RESULTS

TRIM66 protein content was highest in NSCLC cell line A549, compared with BEAS-2B, it showed that the TRIM66-siRNA group lung cancer cell proliferation was significantly reduced after knockdown of TRIM66, and knockdown of TRIM66 also suppressed invasion, migration and clonogenic ability of A549 cells. Finally, we found that siRNA-mediated TRIM66 silencing suppressed EMT by downregulating expression of N-cadherin and vimentin and upregulating that of E-cadherin in NSCLC cells, which could effectively reduce the invasive, migratory, and proliferative capacities of lung cancer cells.

CONCLUSION

Silence TRIM66 expression suppressed NSCLC cell proliferation, invasion, and migration. The siRNA-mediated TRIM66 silencing could block the occurrence of EMT. TRIM66 could be a promising novel target for future NSCLC treatments.