Tripartite Motif-containing Protein 24 Research Articles

Esketamine induces tripartite motif-containing protein 24 to improve cognitive dysfunction in Alzheimer’s disease

Esketamine has been revealed to improve cognitive impairments under different conditions, while its function in Alzheimer’s disease (AD) has not been well characterized. We expounded the effects and detailed mechanism of esketamine in triple transgenic AD (3xTg-AD) mice in the present study. The impaired spatial learning and memory retention of 3xTg-AD mice were ameliorated by esketamine, whereas tripartite motif-containing protein 24 (TRIM24) depletion reversed the ameliorative effects of esketamine in 3xTg-AD mice. Esketamine elevated the extent of PI3K and AKT phosphorylation in the hippocampus by promoting TRIM24 expression, and knockdown of TRIM24 impaired the PI3K/AKT pathway. AD-like mice had increased expression of pro-inflammatory molecules and elevated expression of GFAP and p-Tau. Esketamine reduced inflammation, but its therapeutic effect was reversed by TRIM24 knockdown. The PI3K/AKT pathway blockage exacerbated cognitive deficits and neuroinflammatory responses in mice. Thus, esketamine has the potential to improve the cognitive and memory functions of 3xTg-AD mice by repressing neuroinflammation by activating TRIM24 and the downstream PI3K/AKT pathway.

Abstract 5959: Targeting TRIM11 is a potential therapeutic strategy for malignant gliomas

Abstract Background: TRIM11 (tripartite motif-containing protein 11) belongs to the TRIM/RBCC (the RING B-box coiled-coil) family of E3 ubiquitin ligases. Emerging evidence has demonstrated that TRIM11 is a novel target against cancer and neurodegenerative diseases as it plays vital role in cellular proliferation, differentiation, tumor progression, and apoptosis. Our previous work demonstrated that TRIM11 is over-expressed in high-grade gliomas and promotes proliferation, invasion, migration and tumor growth, suggesting that TRIM11 may be used as a target for malignant glioma treatment. The tumor suppressor p53 plays critical roles in tumor prevention, and deregulated p53 pathway has been found in a majority of glioblastomas (GBMs). Recent studies have shown that TRIM proteins are involved in the regulation of p53, and TRIM proteins are also regulated by p53. Methods: To evaluate the effect of TRIM11 on GBM progression in vivo, we intracranially implanted GBM cells over-expressing TRIM11 in immunocompromised mice, and the animal survival was monitored. We have synthesized a series of TRIM11 inhibitors and evaluated their anti-GBM potential in vitro. Furthermore, we tested the crosstalk between TRIM11 and p53 by knocking down TP53 through RNA interference. Results: Our in vivo data showed that the control group mice (GL261 parent line) survived longer than the mice bearing TRIM11 over-expressing GL261 tumors (p<0.05), suggesting TRIM11 enhances tumor progression in vivo. In vitro data showed that the oncogenic effect of TRIM11 may be related to its influence on the apoptosis pathway since a robust induction of poly (ADP-ribose) polymerase (PARP) was observed in TRIM11 over-expressing GBM cells. When treated with Temozolomide (TMZ), TRIM11 over-expressing cells were more resistant and showed a higher survival rate compared to parental cells. We screened a small library of TRIM11 inhibitors (~ 25 compounds), and identified several compounds which significantly inhibited the growth of both established and primary GBM cells in a dose-dependent manner, implicating that TRIM11 inhibitors may serve as novel agents for GBM treatment. We found that inactivation of p53 by siRNA increased the expression of TRIM11 and modulated the sensitivities of GBM cells to chemotherapy drugs. Conclusion: Despite remarkable advances in the prognosis and multidisciplinary treatment strategies, GBM is still the most lethal primary brain tumor, and there is a pressing need for newer anti-GBM agents with novel targets and mode of action. Our preclinical studies demonstrate a significant anti-tumor effect of TRIM11 inhibitors on malignant glioma cells. Our finding that TRIM11 may be modulated by p53 adds a new layer of regulation to this complicated signaling pathway. A better understanding of the crosstalk between p53 and TRIM11 will benefit the clinical application of targeting p53 and TRIM11 signaling pathways for therapeutical indications in GBM. Citation Format: Kaijun Di, Bhaskar C. Das, Daniela Alexandru Abrams, Daniela A. Bota. Targeting TRIM11 is a potential therapeutic strategy for malignant gliomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5959.

Abstract IA017: An oncogenic histone reader promotes metaplastic TNBC

Abstract Human carcinosarcomas or metaplastic breast cancers (MpBC) are a rare, chemorefractory subclass of triple-negative breast cancers (TNBC). Conditional overexpression of histone reader Tripartite motif containing protein 24 (TRIM24) in mouse mammary epithelia (Trim24COE) led to spontaneous development of mammary carcinosarcoma tumors, lacking ER, PR and HER2, comprising 70% of all mammary tumors that developed with 40% penetrance. We saw strong correlation of Trim24COE carcinosarcoma tumors with human MpBC tumors and derived a conserved Trim24COE gene signature of Glycolysis, EMT and mTORC1 signaling pathways. Global and single-cell tumor profiling revealed Met as a direct oncogenic target of TRIM24, leading to aberrant PI3K/mTOR activation. To assess TRIM24-dependent metabolic alterations, we developed Trim24COE carcinosarcoma spheroid cultures. Tumor-derived Trim24COE carcinosarcoma spheroids exhibit TRIM24-dependent EMT and repressed cellular and mitochondrial ROS levels. We found that TRIM24 expression increased c-myc, NADPH and NRF2 levels to drive ROS repression and TRIM24-dependent cell survival under oxidative stress. TRIM24 mediates NRF2 activation at the level of chromatin structure activation, as shown by ATAC-seq of Trim24COE and shTrim24 carcinosarcoma spheroids. These in vivo and ex vivo models of metaplastic TNBC offer a platform for mechanistic discovery and nomination of potential therapeutic avenues for this highly malignant TNBC subtype. Citation Format: Vrutant V. Shah, Shucheng Miao, Patrick M. Krause, Sabrina A. Stratton, Lalit R. Patel, Michelle C. Barton. An oncogenic histone reader promotes metaplastic TNBC [abstract]. In: Proceedings of the AACR Special Conference: Aging and Cancer; 2022 Nov 17-20; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_1):Abstract nr IA017.

TRIM11 Posttranscriptionally Modulated by miR-5193 Facilitates Tumor Growth and Metastasis of Prostate Cancer.

Tripartite motif-containing protein 11 (TRIM11), an E3 ubiquitin ligase, possesses a pro-tumor property. Still, the detailed functions of TRIM11 remain not well characterized in prostate cancer. PC-3 and DU145 prostate cancer cells were transfected with small interfering RNAs (siRNAs) or lentiviruses for TRIM11 deficiency or overexpression, and microRNA-5193 (miR-5193) mimics were utilized for overexpressing miR-5193. Proliferation, apoptosis, migration, and invasion were examined through CCK-8, colony formation, flow cytometry, wound healing, and transwell assays. MAP kinase-extracellular signal-regulated kinase (MEK1/2) and extracellular signal-regulated kinase (ERK)1/2 activities were detected via immunoblotting. Murine xenograft models were established. Interactions of TRIM11 with miR-5193 were demonstrated via dual luciferase reporter. TRIM11 deficiency or miR-5193 overexpression exerted antiprostate cancer effects through suppression of proliferation, migration, and invasion as well as enhancement of apoptosis in PC-3 and DU145 cells. The mechanisms by which TRIM11 deficiency or miR-5193 overexpression involved the inactivation of MEK1/2 and ERK1/2. miR-5193 downregulated TRIM11 expressions in prostate cancer cells, and their interactions were confirmed. Further, up-regulated miR-5193 weakened the effects of TRIM11 overexpression on enhancing proliferation, migration, invasion, and activity of MEK1/2 and ERK1/2 as well as alleviating apoptosis of prostate cancer cells. In murine xenograft models, TRIM11 upregulation facilitated tumor growth, which was alleviated by miR-5193 overexpression. These findings described the oncogenic role of TRIM11 in prostate cancer biology, which was post-transcriptionally modulated by miR-5193.

TRIM24 is critical for the cellular response to DNA double-strand breaks through regulating the recruitment of MRN complex.

The MRE11-RAD50-NBS1 (MRN) complex plays a crucial role in DNA double-strand breaks (DSBs) sensing and initiation of signaling cascades. However, the precise mechanisms by which the recruitment of MRN complex is regulated has yet to be elucidated. Here, we identified TRIpartite motif-containing protein 24 (TRIM24), a protein considered as an oncogene overexpressed in cancers, as a novel signaling molecule in response to DSBs. TRIM24 is essential for DSBs-induced recruitment of MRN complex and activation of downstream signaling. In the absence of TRIM24, MRN mediated DSBs repair is remarkably diminished. Mechanistically, TRIM24 is phosphorylated by ataxia-telangiectasia mutated (ATM) and then recruited to DSBs sites, facilitating the accumulation of the MRN components to chromatin. Depletion of TRIM24 sensitizes human hepatocellular carcinoma cells to cancer therapy agent-induced apoptosis and retards the tumor growth in a subcutaneous xenograft tumor mouse model. Together, our data reveal a novel function of TRIM24 in response to DSBs through regulating the MRN complex, which suggests that TRIM24 may be a potential therapeutic molecular target for tumor treatment.

TRIM11, a new target of p53, facilitates the migration and invasion of nasopharyngeal carcinoma cells

BackgroundAlthough tripartite motif-containing protein 11 (TRIM11) is known to be associated with a variety of cancers, its role in nasopharyngeal carcinoma (NPC) is unclear.Methods and resultsTo investigate the role of TRIM11 in NPC, TRIM11 was stably overexpressed in 6–10B and CNE2 cells with lentiviral vectors and knocked down in S18 and 5–8F cells using the CRISPR/Cas9 system. Transwell assays and wound-healing assays revealed that TRIM11 facilitated the migration and invasion of NPC cells. Mechanistically, we found that p53 inhibits TRIM11 expression by binding to its promoter.ConclusionsTRIM11 may serve as a potential diagnostic marker for NPC and has a certain therapeutic value.

Discovery, optimization and evaluation of 1-(indolin-1-yl)ethan-1-ones as novel selective TRIM24/BRPF1 bromodomain inhibitors

TRIM24 (tripartite motif-containing protein 24) and BRPF1 (bromodomain and PHD finger containing protein 1) are epigenetics “readers” and potential therapeutic targets for cancer and other diseases. Here we describe the structure-guided design of 1-(indolin-1-yl)ethan-1-ones as novel TRIM24/BRPF1 bromodomain inhibitors. The representative compound 20l (Y08624) is a new TRIM24/BRPF1 dual inhibitor, with IC50 values of 0.98 and 1.16 μM, respectively. Cellular activity of 20l was validated by viability assay in prostate cancer (PC) cell lines. In PC xenograft models, 20l suppressed tumor growth (50 mg/kg/day, TGI = 53%) without exhibiting noticeable toxicity. Compound 20l represents a versatile starting point for the development of more potent TRIM24/BRPF1 inhibitors.

Abstract P3-05-01: Role of TRIM24 in metaplastic breast cancer and nomination of potential therapeutic targets

Abstract Background: Within the Triple-Negative Breast Cancer (TNBC) subclass, metaplastic TNBC (MpBC) tumors are comprised of heterogeneous, malignant epithelial (carcinoma) and mesenchymal (sarcoma) elements and are rare, highly aggressive, poorly differentiated and chemorefractory. There is an unmet need to develop therapies that address and improve survival of MpBC TNBC patients. We and others found that protein and mRNA levels of tripartite motif-containing protein 24 (TRIM24) are elevated in breast cancers, and aberrant expression of TRIM24 is linked to poor patient survival. Our previous in vitro studies showed that TRIM24 is a multidomain protein with histone reader function via a PHD/bromodomain and E3 ligase function via a RING domain that targets p53 for degradation.Methods: To determine if TRIM24 is oncogenic in vivo, we created a mouse model with conditional over expression (COE) of TRIM24 in mammary epithelia (Trim24COE). Trim24COE mice develop tumors, which were subjected to pathology, immunohistochemistry, global transcriptional and single-cell protein expression profiling. Additionally, we determined expression of TRIM24 in MpBC patient-derived tumor arrays and xenografts (PDX). Trim24COE tumor-derived primary cell lines and 3D spheroids were assessed for function and response to targeted inhibition.Results: TRIM24 over expression is sufficient to drive development of murine metaplastic carcinosarcomas (70% of all tumors), which are highly penetrant and lacking ER, PR and HER2 expression. Using global RNA-sequencing and selected proteomic profiling (RPPA) followed by CyTOF, we found that EMT, glycolysis, angiogenesis, G2/M checkpoint regulators and cMET/PI3K/mTOR are top up-regulated pathways. We defined a TRIM24 gene expression signature for Trim24COE tumors to probe TNBC patient expression data and found that the TRIM24 signature positively correlates with MpBC TNBC. Using a PROTAC targeting TRIM24, we showed that degradation of TRIM24 reduces cell viability compared to control, both in TRIM24-driven primary tumor cell lines and MpBC PDX cell suspensions. Carbon 13 (C13) tracing and other metabolomics were used to determine the impact of TRIM24 in metabolic pathways, using 3D spheroids derived from Trim24COE carcinosarcomas. We found that up-regulation of TRIM24 lowers ROS to promote cell survival by increased production of NADPH via multiple metabolic pathways that can be reversed by knocking-down TRIM24 or with specific metabolic inhibitors.Conclusions: TRIM24 is a PHD/bromodomain histone reader and p53-targeting E3-ubiquitin ligase that, when aberrantly over expressed, promotes tumorigenesis in vivo. A majority of Trim24-driven tumors are carcinosarcomas, highly similar to MpBC TNBC. Genomewide RNA expression and protein profiling show TRIM24 over expression activates EMT and disrupts metabolic homeostasis. Findings from our mouse model are relevant to tumors derived from MpBC patients, as PDXs show high expression of TRIM24 and respond to PROTAC treatment of TRIM24. Further establishment of TRIM24’s role in metabolic pathways to reduce ROS and increase cell survival may reveal potential combinatorial therapeutic approaches for MpBC. These findings suggest exciting opportunities to exploit the Trim24COE mouse model as a means of understanding mechanisms of MpBC tumor development and for preclinical studies of new, epigenetic-based therapeutic approaches. Citation Format: Vrutant Shah, Shucheng Miao, Clinton Yam, Jeffrey T Chang, Michelle Barton, Helen Piwnica-Worms, Stacy Moulder, Guillermina Lozano. Role of TRIM24 in metaplastic breast cancer and nomination of potential therapeutic targets [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-05-01.

Tripartite motif-containing protein 11 promotes hepatocellular carcinogenesis through ubiquitin-proteasome-mediated degradation of pleckstrin homology domain leucine-rich repeats protein phosphatase 1.

HCC is one of the main types of primary liver cancer, with high morbidity and mortality and poor treatment effect. Tripartite motif-containing protein 11 (TRIM11) has been shown to promote tumor formation in lung cancer, breast cancer, gastric cancer, and so on. However, the specific function and mechanism of TRIM11 in HCC remain open for study. Through clinical analysis, we found that the expression of TRIM11 was up-regulated in HCC tissues and was associated with high tumor node metastasis (TNM) stages, advanced histological grade, and poor patient survival. Then, by gain- and loss-of-function investigations, we demonstrated that TRIM11 promoted cell proliferation, migration, and invasion in vitro and tumor growth in vivo. Mechanistically, RNA sequencing and mass spectrometry analysis showed that TRIM11 interacted with pleckstrin homology domain leucine-rich repeats protein phosphatase 1 (PHLPP1) and promoted K48-linked ubiquitination degradation of PHLPP1 and thus promoted activation of the protein kinase B (AKT) signaling pathway. Moreover, overexpression of PHLPP1 blocked the promotional effect of TRIM11 on HCC function. Our study confirmed that TRIM11 plays an oncogenic role in HCC through the PHLPP1/AKT signaling pathway, suggesting that targeting TRIM11 may be a promising target for the treatment of HCC.

Tripartite Motif-Containing Protein 11 Reverses Paclitaxel Resistance in Prostate Cancer Drug-Resistant Cells by Mediating Family with Sequence Similarity 46B Expression

Tripartite motif-containing protein 11 (TRIM11) and family with sequence similarity 46B (FAM46B) have been demonstrated to play roles in prostate cancer development, but their function in paclitaxel resistance remains unclear. The role of TRIM11 and FAM46B in paclitaxel resistance in prostate cancer was estimated. The paclitaxel-resistant cells were established with gradually increasing concentrations of paclitaxel in prostate cancer cells. The sensitivity to paclitaxel of established cells was assessed by the value of the median inhibitory concentration in the presence of 0-1000 nM paclitaxel. The expression level of TRIM11 and FAM46B was evaluated by real-time quantitative polymerase chain reaction. The proliferation, migration, and invasion of established cells were evaluated by CCK8 and Tran-swell assay. TRIM11 was upregulated in paclitaxel-resistant cells and promoted the proliferation, migration, and invasion of established cells. The significant downregulation of FAM46B was observed in paclitaxel-resistant cells. Although the overexpression of FAM46B suppressed the viability and metastasis of paclitaxel-resistant cells, which was reversed by the upregulation of TRIM11. Both the knockdown of TRIM11 and overexpression of FAM46B could enhance paclitaxel sensitivity of established resistant cells. The promoted effect of FAM46B overexpression was alleviated by the elevation of TRIM11. TRIM11 could improve the sensitivity to paclitaxel of resistant prostate cancer cells via regulating FAM46B.

Mammary-specific expression of Trim24 establishes a mouse model of human metaplastic breast cancer

Conditional overexpression of histone reader Tripartite motif containing protein 24 (TRIM24) in mouse mammary epithelia (Trim24COE) drives spontaneous development of mammary carcinosarcoma tumors, lacking ER, PR and HER2. Human carcinosarcomas or metaplastic breast cancers (MpBC) are a rare, chemorefractory subclass of triple-negative breast cancers (TNBC). Comparison of Trim24COE metaplastic carcinosarcoma morphology, TRIM24 protein levels and a derived Trim24COE gene signature reveals strong correlation with human MpBC tumors and MpBC patient-derived xenograft (PDX) models. Global and single-cell tumor profiling reveal Met as a direct oncogenic target of TRIM24, leading to aberrant PI3K/mTOR activation. Here, we find that pharmacological inhibition of these pathways in primary Trim24COE tumor cells and TRIM24-PROTAC treatment of MpBC TNBC PDX tumorspheres decreased cellular viability, suggesting potential in therapeutically targeting TRIM24 and its regulated pathways in TRIM24-expressing TNBC.

Downregulation of circEPSTI1 represses the proliferation and invasion of non-small cell lung cancer by inhibiting TRIM24 via miR-1248 upregulation

The circular RNA (circRNA) circEPSTI1 has been recently identified as a new cancer-associated circRNA in multiple types of cancer. However, the involvement of circEPSTI1 in non-small cell lung cancer (NSCLC) remains unexplored. The purpose of this study was to explore the expression pattern and function of circEPSTI1 in NSCLC. We found that circEPSTI1 expression was significantly elevated in NSCLC. In vitro experiments elucidated that knockdown of circEPSTI1 caused a significant reduction in NSCLC cell proliferation and invasion. Moreover, circEPSTI1 was identified as an miRNA sponge of miRNA-1248. Knockdown of circEPSTI1 markedly increased the expression of miR-1248 in NSCLC cells. Upregulation of miR-1248 significantly restricted the proliferation and invasion of NSCLC cells. Inhibition of miR-1248 promoted the proliferation and invasion of NSCLC cells and blocked the circEPSTI1 knockdown-mediated inhibitory effect on NSCLC cell proliferation and invasion. Subsequent data revealed that the tumor-promoting gene tripartite motif-containing protein 24 (TRIM24) is a target gene of miR-1248. The upregulation of TRIM24 partially reversed circEPSTI1 knockdown- or miR-1248 overexpression-induced tumor suppressive effect in NSCLC cells. In summary, our data demonstrate that downregulation of circEPSTI1 represses the proliferation and invasion of NSCLC by inhibiting TRIM24 via miR-1248 upregulation.

Knockdown of TRIM24 suppresses growth and induces apoptosis in acute myeloid leukemia through downregulation of Wnt/GSK-3β/β-catenin signaling.

Tripartite motif-containing protein 24 (TRIM24) has currently emerged as a crucial cancer-related gene present in a wide range of human cancer types. However, the involvement of TRIM24 in acute myeloid leukemia (AML) has not been well investigated. The present study aims to investigate the significance, cellular function, and potential regulatory mechanism of TRIM24 in AML. We found that TRIM24 expression was significantly upregulated in AML compared with normal tissues. AML patients with low expression of TRIM24 had higher survival rates than those expressing TRIM24 at higher levels. High expression of TRIM24 was also detected in AML cells and its knockdown markedly restricted proliferation and promoted apoptosis in AML cells. Further investigation revealed that TRIM24 contributed to the regulation of Wnt/β-catenin signaling, which was associated with modulating the phosphorylation status of glycogen synthase kinase-3β (GSK-3β). Inactivation of GSK-3β partially reversed the TRIM24 knockdown-mediated antitumor effects observed in AML cells. Furthermore, knockdown of TRIM24 retarded the growth of AML-derived xenograft tumors in nude mice in vivo. Overall, these findings demonstrate that knockdown of TRIM24 impedes the AML tumor growth through the modulation of Wnt/GSK-3β/β-catenin signaling. These findings highlight the potential TRIM24 as an attractive anticancer target to treat AML.

Abstract P1-03-01: A novel model to study to metaplastic TNBC

Abstract Background: Triple-Negative Breast Cancers (TNBC), a broad class of breast cancers lacking estrogen- and progesterone-receptor (ER and PR) response and HER2 amplification, remain refractory to hormone-based or molecularly targeted therapies. Within the TNBC subclass, carcinosarcomas or metaplastic breast cancers (MpBC) are a heterogeneous mixture of malignant epithelial and mesenchymal elements that develop highly aggressive, rare, poorly differentiated and chemorefractory tumors. There is an unmet need to develop innovative treatments for TNBC, in general, and MpBC, in particular. In human breast carcinomas, both protein and mRNA levels of tripartite motif containing protein 24 (TRIM24) are elevated, and aberrant expression of TRIM24 is linked to poor patient survival. Previous in vitro studies determined that TRIM24 is a multidomain protein with histone reader function via a PHD/bromodomain and E3 ligase function via a RING domain. Method: To determine if TRIM24 is oncogenic in vivo, our lab created a mouse model that conditionally overexpresses (COE) TRIM24 in mammary epithelia (Trim24COE). Trim24COE mice develop tumors, which were subjected to pathology, immunohistochemistry, global transcriptional and translational profile. Additionally, we determined expression of TRIM24 in MpBC patient-derived tumor arrays and xenografts (PDX). Trim24COE tumor-derived primary cell lines were assessed for function and therapeutic response. Results: Surprisingly, TRIM24 overexpression is sufficient to drive development of murine MpBC (70% of all tumors), which are highly penetrant and lack ER, PR and HER2 expression. Preliminary results also show highly specific expression of TRIM24 in MpBC PDXs, supporting TRIM24 as a relevant oncogene in human MpBC. Gene expression profiles of TRIM24-driven mice tumors, compared to MMTV-Cre controls, showed that EMT, glycolysis, angiogenesis and G2/M Checkpoint regulators are among the top up-regulated pathways. Selected proteomics profile (RPPA) also shows pathways related to glycolysis, G2/M checkpoint and E2F targets are top up-regulated pathways. We matched TRIM24 expression signatures from TRIM24-driven tumors to TNBC patients and found that TRIM24 signatures are positively correlated to MpBC subtypes. Using a PROTAC targeting TRIM24, we showed that degradation of TRIM24 is sufficient to reduce cell viability compared to control, both in TRIM24-driven primary cell lines and MpBC PDX cell suspension. Conclusions: TRIM24 is a bromodomain histone reader and p53-targeting E3-ubiquitin ligase, which is sufficient to promote tumorigenesis in vivo. A majority of Trim24-driven tumors is classified as MpBC TNBC. Genomewide RNA expression and protein profiling showed TRIM24 overexpression activates EMT and G2/M regulators. Our preliminary results show the TRIM24-PROTAC is promising as a future therapeutic approach towards MpBC. Findings from our mouse model are relevant to tumors derived from MpBC patients, as PDXs show high expression of TRIM24 and respond to PROTAC treatment of TRIM24. These findings suggest exciting opportunities to exploit the Trim24COE mouse model as a means of understanding mechanisms of MpBC tumor development and for preclinical studies of new, epigenetic-based therapeutic approaches. Citation Format: Vrutant Shah, Sabrina Stratton, Shiming Jiang, Jeffrey Chang, Helen Piwnica-Worms, Stacy Moulder, Michelle Barton. A novel model to study to metaplastic TNBC [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-03-01.

Discovery and optimization of novel N-benzyl-3,6-dimethylbenzo[d]isoxazol-5-amine derivatives as potent and selective TRIM24 bromodomain inhibitors with potential anti-cancer activities.

Tripartite motif-containing protein 24 (TRIM24), recognized as an epigenetic reader for acetylated H3K23 (H3K23ac) via its bromodomain, has been closely involved in tumorigenesis or tumor progression of several cancers. Developing inhibitors of TRIM24 is significant for functional studies and drug discovery. Herein, we report the identification, optimization and evaluation of N-benzyl-3,6-dimethylbenzo[d]isoxazol-5-amines as TRIM24 bromodomain inhibitors starting from an in house library screening. Structure-based optimization leads to two potent and selective compounds 11d and 11h in an Alphascreen assay with IC50 values of 1.88 μM and 2.53 μM, respectively. The viability assay demonstrates the great potential of this series of compounds as inhibitors of proliferation of prostate cancer (PC) cells LNCaP, C4-2B. A colony formation assay further supports this inhibitory activity. Compounds 11d and 11h inhibit cell proliferation of other cancer types such as non-small cell lung cancer (NSCLC) cells A549 with IC50 values of 1.08 μM and 0.75 μM, respectively. These data suggests that compounds 11d and 11h are promising lead compounds for further research.

TRIM11 promotes proliferation and glycolysis of breast cancer cells via targeting AKT/GLUT1 pathway.

Background: Tripartite motif-containing protein 11 (TRIM11) is one of the E3 ubiquitin ligases, which is upregulated in several human tumors. Meanwhile, the detailed function of TRIM11 remains unclear in breast cancer cells.Purpose: The purpose of the present study is to analyze the biological function of TRIM11 and identify its potential signaling pathway in breast cancer cells.Patients and methods: Thirty five pairs of breast cancer specimens and adjacent-matched noncancerous samples were used to analyse the expression profile of TRIM11. RNA interference was utilized to silence TRIM11 in three breast cancer cell lines (T47D, ZR7530, and BT474) respectively. Meanwhile, overexpression of TRIM11 was induced in one breast cancer cells (MDA-MB-231) by using Lentiviral vector. Moreover, the AKT inhibitor (MK-2206) was used to determine the correlation between TRIM11 and AKT in breast cancer cells.Results: Our results indicated that TRIM11 was increased in breast cancer tissues. Moreover, TRIM11 was a pro-proliferation regulator in breast cancer cells and participated in the metabolism of glycolysis. Importantly, our results demonstrated that TRIM11 was involved in the AKT/GLUT1 signaling pathway in breast cancer cells.Conclusion: Present research not only gained a deep understanding of the biological function of TRIM11 but also provided evidences to indicate its possible signaling pathway in breast cancer cells.

Variation at the TRIM11 locus modifies progressive supranuclear palsy phenotype.

ObjectiveThe basis for clinical variation related to underlying progressive supranuclear palsy (PSP) pathology is unknown. We performed a genome‐wide association study (GWAS) to identify genetic determinants of PSP phenotype.MethodsTwo independent pathological and clinically diagnosed PSP cohorts were genotyped and phenotyped to create Richardson syndrome (RS) and non‐RS groups. We carried out separate logistic regression GWASs to compare RS and non‐RS groups and then combined datasets to carry out a whole cohort analysis (RS = 367, non‐RS = 130). We validated our findings in a third cohort by referring to data from 100 deeply phenotyped cases from a recent GWAS. We assessed the expression/coexpression patterns of our identified genes and used our data to carry out gene‐based association testing.ResultsOur lead single nucleotide polymorphism (SNP), rs564309, showed an association signal in both cohorts, reaching genome‐wide significance in our whole cohort analysis (odds ratio = 5.5, 95% confidence interval = 3.2–10.0, p = 1.7 × 10−9). rs564309 is an intronic variant of the tripartite motif‐containing protein 11 (TRIM11) gene, a component of the ubiquitin proteasome system (UPS). In our third cohort, minor allele frequencies of surrogate SNPs in high linkage disequilibrium with rs564309 replicated our findings. Gene‐based association testing confirmed an association signal at TRIM11. We found that TRIM11 is predominantly expressed neuronally, in the cerebellum and basal ganglia.InterpretationOur study suggests that the TRIM11 locus is a genetic modifier of PSP phenotype and potentially adds further evidence for the UPS having a key role in tau pathology, therefore representing a target for disease‐modifying therapies. Ann Neurol 2018;84:485–496

Cross-talk between chromatin acetylation and SUMOylation of tripartite motif–containing protein 24 (TRIM24) impacts cell adhesion

Proteins with domains that recognize and bind post-translational modifications (PTMs) of histones are collectively termed epigenetic readers. Numerous interactions between specific reader protein domains and histone PTMs and their regulatory outcomes have been reported, but little is known about how reader proteins may in turn be modulated by these interactions. Tripartite motif-containing protein 24 (TRIM24) is a histone reader aberrantly expressed in multiple cancers. Here, our investigation revealed functional cross-talk between histone acetylation and TRIM24 SUMOylation. Binding of TRIM24 to chromatin via its tandem PHD-bromodomain, which recognizes unmethylated lysine 4 and acetylated lysine 23 of histone H3 (H3K4me0/K23ac), led to TRIM24 SUMOylation at lysine residues 723 and 741. Inactivation of the bromodomain, either by mutation or with a small-molecule inhibitor, IACS-9571, abolished TRIM24 SUMOylation. Conversely, inhibition of histone deacetylation markedly increased TRIM24's interaction with chromatin and its SUMOylation. Of note, gene expression profiling of MCF7 cells expressing WT versus SUMO-deficient TRIM24 identified cell adhesion as the major pathway regulated by the cross-talk between chromatin acetylation and TRIM24 SUMOylation. In conclusion, our findings establish a new link between histone H3 acetylation and SUMOylation of the reader protein TRIM24, a functional connection that may bear on TRIM24's oncogenic function and may inform future studies of PTM cross-talk between histones and epigenetic regulators.

A histone reader becomes the readout

Chromatin signaling events are critical for the dynamic regulation of the genome. Although much has been learned about histone modification in these events, the modification of nonhistone chromatin regulators and cross-talk between these pathways is less well understood. Here, Appikonda et al. demonstrate that the transcription co-factor and oncoprotein TRIM24 (tripartite motif-containing protein 24) is SUMOylated upon association with a specific histone modification signature, which regulates the transcription of genes involved in cell adhesion. These data extend our understanding of signaling cascades in the nucleus and offer new insights for cancer drug development.

TRIM24 protein promotes and TRIM32 protein inhibits cardiomyocyte hypertrophy via regulation of dysbindin protein levels

We have previously shown that dysbindin is a potent inducer of cardiomyocyte hypertrophy via activation of Rho-dependent serum-response factor (SRF) signaling. We have now performed a yeast two-hybrid screen using dysbindin as bait against a cardiac cDNA library to identify the cardiac dysbindin interactome. Among several putative binding proteins, we identified tripartite motif-containing protein 24 (TRIM24) and confirmed this interaction by co-immunoprecipitation and co-immunostaining. Another tripartite motif (TRIM) family protein, TRIM32, has been reported earlier as an E3 ubiquitin ligase for dysbindin in skeletal muscle. Consistently, we found that TRIM32 also degraded dysbindin in neonatal rat ventricular cardiomyocytes as well. Surprisingly, however, TRIM24 did not promote dysbindin decay but rather protected dysbindin against degradation by TRIM32. Correspondingly, TRIM32 attenuated the activation of SRF signaling and hypertrophy due to dysbindin, whereas TRIM24 promoted these effects in neonatal rat ventricular cardiomyocytes. This study also implies that TRIM32 is a key regulator of cell viability and apoptosis in cardiomyocytes via simultaneous activation of p53 and caspase-3/-7 and inhibition of X-linked inhibitor of apoptosis. In conclusion, we provide here a novel mechanism of post-translational regulation of dysbindin and hypertrophy via TRIM24 and TRIM32 and show the importance of TRIM32 in cardiomyocyte apoptosis in vitro.