Expression of RET finger protein predicts chemoresistance in epithelial ovarian cancer

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.

Role of the tripartite motif (TRIM) family in female genital neoplasms

The tripartite motif proteins (TRIMs) family represents a class of highly conservative proteins which play a large regulatory role in molecular processes. Recently, increasing evidence has demonstrated a role of TRIMs in female genital neoplasms. Our review thereby aimed to provide an overview of the biological involvement of TRIMs in female genital neoplasms, to provide a better understanding of its role in the development and progression of such diseases, and emphasize its potential as targeted cancer therapy. Overall, our review highlighted that the wide-ranging roles of TRIMs, in not only target protein ubiquitination, tumor migration and/or invasion, epithelial-mesenchymal transition, stemness, cell adhesion, proliferation, cell cycle regulation, and apoptosis, but also in influencing estrogenic, and chemotherapy response.

TRIM27 is an autophagy substrate facilitating mitochondria clustering and mitophagy via phosphorylated TBK1

Tripartite motif-containing protein 27 (TRIM27/also called RFP) is a multifunctional ubiquitin E3 ligase involved in numerous cellular functions, such as proliferation, apoptosis, regulation of the NF-kB pathway, endosomal recycling and the innate immune response. TRIM27 interacts directly with TANK-binding kinase 1 (TBK1) and regulates its stability. TBK1 in complex with autophagy receptors is recruited to ubiquitin chains assembled on the mitochondrial outer membrane promoting mitophagy. Here, we identify TRIM27 as an autophagy substrate, depending on ATG7, ATG9 and autophagy receptors for its lysosomal degradation. We show that TRIM27 forms ubiquitylated cytoplasmic bodies that co-localize with autophagy receptors. Surprisingly, we observed that induced expression of EGFP-TRIM27 in HEK293 FlpIn TRIM27 knockout cells mediates mitochondrial clustering. TRIM27 interacts with autophagy receptor SQSTM1/p62, and the TRIM27-mediated mitochondrial clustering is facilitated by SQSTM/p62. We show that phosphorylated TBK1 is recruited to the clustered mitochondria. Moreover, induced mitophagy activity is reduced in HEK293 FlpIn TRIM27 knockout cells, while re-introduction of EGFP-TRIM27 completely restores the mitophagy activity. Inhibition of TBK1 reduces mitophagy in HEK293 FlpIn cells and in the reconstituted EGFP-TRIM27-expressing cells, but not in HEK293 FlpIn TRIM27 knockout cells. Altogether, these data reveal novel roles for TRIM27 in mitophagy, facilitating mitochondrial clustering via SQSTM1/p62 and mitophagy via stabilization of phosphorylated TBK1 on mitochondria.

TRIM27 is an adverse prognostic biomarker and associated with immune and molecular profiles in right-sided colon cancer

Right-sided colon cancer (RCC), as an independent tumor entity, shows a poor prognosis. It is imperative to detect immune microenvironment-related genes for predicting RCC patient prognosis and study their function in RCC. Tripartite motif-containing 27 (TRIM27) was identified as a risk signature from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) datasets by using weighted gene co-expression network analysis, differentially expressed analysis, and univariate Cox analysis. It predicted a poorer overall survival and increased lymph node metastasis, which were then validated in our 48 clinical samples. Using immunohistochemistry, TRIM27 was found to be highly expressed in both cancer cells and surrounding immunocytes, and its expression in tumor or immune cells both predicted a poorer prognosis. Thereafter, the functional mechanism, immune and molecular characteristics of TRIM27 were investigated using gene set enrichment analysis (GSEA), ESTIMATE, CIBERSORT, and gene set variation analysis (GSVA) at the single-cell, somatic mutation, and RNA-seq level. Patients with highly expressed TRIM27 presented lower CD4⁺ T cell infiltration and activation of the mTORC1/glycolysis pathway. In addition, patients with highly expressed TRIM27 were characterized by hypermetabolism, higher tumor purity, more BRAF mutation, and more chromosomal instability. Collectively, TRIM27 is an important immune-related prognostic biomarker in patients with RCC. It may function via activating the mTORC1/glycolysis pathway and suppressing CD4⁺ T cells. These results indicated that TRIM27 could be a promising therapeutic target in RCC.

Emerging roles of TRIM27 in cancer and other human diseases

As a member of the TRIM protein family, TRIM27 is a RING-mediated E3 ubiquitin ligase that can mark other proteins for degradation. Its ubiquitination targets include PTEN, IκBα and p53, which allows it to regulate many signaling pathways to exert its functions under both physiological and pathological conditions, such as cell proliferation, differentiation and apoptosis. During the past decades, TRIM27 was reported to be involved in many diseases, including cancer, lupus nephritis, ischemia-reperfusion injury and Parkinson’s disease. Although the research interest in TRIM27 is increasing, there are few reviews about the diverse roles of this protein. Here, we systematically review the roles of TRIM27 in cancer and other human diseases. Firstly, we introduce the biological functions of TRIM27. Next, we focus on the roles of TRIM27 in cancer, including ovarian cancer, breast cancer and lung cancer. At the same time, we also describe the roles of TRIM27 in other human diseases, such as lupus nephritis, ischemia-reperfusion injury and Parkinson’s disease. Finally, we discuss the future directions of TRIM27 research, especially its potential roles in tumor immunity.

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

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

The testis protein ZNF165 is a SMAD3 cofactor that coordinates oncogenic TGFβ signaling in triple-negative breast cancer

Cancer/testis (CT) antigens are proteins whose expression is normally restricted to germ cells yet aberrantly activated in tumors, where their functions remain relatively cryptic. Here we report that ZNF165, a CT antigen frequently expressed in triple-negative breast cancer (TNBC), associates with SMAD3 to modulate transcription of transforming growth factor β (TGFβ)-dependent genes and thereby promote growth and survival of human TNBC cells. In addition, we identify the KRAB zinc finger protein, ZNF446, and its associated tripartite motif protein, TRIM27, as obligate components of the ZNF165-SMAD3 complex that also support tumor cell viability. Importantly, we find that TRIM27 alone is necessary for ZNF165 transcriptional activity and is required for TNBC tumor growth in vivo using an orthotopic xenograft model in immunocompromised mice. Our findings indicate that aberrant expression of a testis-specific transcription factor is sufficient to co-opt somatic transcriptional machinery to drive a pro-tumorigenic gene expression program in TNBC.

Downregulation of TRIM27 suppresses gastric cancer cell proliferation via inhibition of the Hippo-BIRC5 pathway

Although tripartite motif containing 27 (TRIM27) protein has been implicated in the progression of many cancer types, its role in gastric cancer (GC) remains poorly understood. Given that TRIM27 may be associated with the baculoviral inhibitor of apoptosis repeat containing 5 (BIRC5) gene, which is downstream of the Hippo pathway, we clarified their relationship in GC progression. In vitro cultures of 7 GC cell lines, 92 GC patient tumor samples and 46 normal clinical samples were used to examine the influence of changes in TRIM27 expression, which was assessed by quantitative PCR, immunohistochemistry, western blot analysis, and cell viability assays. We found that TRIM27 overexpression was correlated with tumor size, depth of invasion, and poor GC prognosis, while TRIM27 small interfering RNA knockdown inhibited cell proliferation and colony formation, induced apoptosis, and increased sensitivity towards 5-fluorouracil treatment in MGC-803 and HGC-27 GC cell lines. Notably, TRIM27 downregulation resulted in BIRC5 suppression via large tumor suppressor kinase 2 (LATS2) upregulation and subsequent Yes-associated protein 1 (YAP1) inhibition in MGC-803 and HGC-27 GC cell lines. In conclusion, our findings revealed the positive correlation between TRIM27 and GC progression through mediation of the Hippo-BIRC5 axis in GC.

Aberrant Active cis-Regulatory Elements Associated with Downregulation of RET Finger Protein Overcome Chemoresistance in Glioblastoma

RET finger protein (RFP) forms a complex with histone deacetylase 1, resulting in aberrant deacetylation of H3K27ac and dysregulation of cis-regulatory elements. We evaluated the modulatory effects of RFP knockdown on cis-regulatory elements, gene expression, and chemosensitivity to temozolomide both in glioblastoma cells and in an intracranial glioblastoma model. The combination of RFP knockdown and temozolomide treatment markedly suppressed the glioblastoma cell growth due to oxidative stress and aberrant cell cycle and increased survival time in mice with glioblastoma. ChIP-seq and RNA-seq revealed that RFP knockdown increased or decreased activity of numerous cis-regulatory elements that lie adjacent to genes that control functions such as apoptosis, mitosis, DNA replication, and cell cycle: FOXO1, TBP2, and PARPBP. This study suggests that RFP contributes to chemoresistance via aberrant deacetylation of histone H3 at K27, whereas dysregulation of RFP-associated cis-regulatory elements in glioma and RFP knockdown combined with temozolomide is an effective treatment strategy for lethal glioma.

miR-30b-3p Inhibits Proliferation and Invasion of Hepatocellular Carcinoma Cells via Suppressing PI3K/Akt Pathway

Background: The micro-RNA miR-30b-3p has been reported to play a crucial role in several cancers. However, the biological function of miR-30b-3p in hepatocellular carcinoma (HCC) is still unknown.

Methods: RT-qPCR was employed to determine the expression of miR-30b-3p in HCC tissues and cells. The MTT assay, colony formation assay, and cell migration and invasion assay were employed to evaluate the role of miR-30b-3p in HCC cells. A dual-luciferase reporter assay was employed to verify the target of miR-30b-3p. Western blotting was employed to determine the expression of key molecular signal transducers along TRIM27-PI3K/Akt axis.

Results: Expression of miR-30b-3p was markedly decreased in HCC tissues and cells and positively correlated with higher overall survival. Moreover, miR-30b-3p overexpression significantly repressed cell viability, proliferation, migration, and invasion of HCC cells in vitro. Notably, we demonstrated that miR-30b-3p directly bound to the 3′-untranslated region of tripartite motif containing 27 (TRIM27) mRNA by downregulating the expression of TRIM27, which was demonstrated to be negatively correlated with miR-30b-3p expression. TRIM27 was demonstrated to have an oncogenic role in HCC cells by enhancing cell viability, proliferation, migration, and invasion. Finally, the miR-30-3p-TRIM27-PI3K/Akt axis was shown to play a crucial role in HCC cells in vitro.

Conclusion: Our results indicated that miR-30-3p might act as a new biomarker for the future diagnosis and treatment HCC.

TRIM27 mediates STAT3 activation at retromer-positive structures to promote colitis and colitis-associated carcinogenesis

STAT3 is a transcription factor that plays central roles in various physiological processes and its deregulation results in serious diseases including cancer. The mechanisms on how STAT3 activity is regulated remains enigmatic. Here we identify TRIM27 as a positive regulator of II-6-induced STAT3 activation and downstream gene expression. TRIM27 localizes to retromer-positive punctate structures and serves as a critical link for recruiting gp130, JAK1, and STAT3 to and subsequent phosphorylation of STAT3 at the retromer-positive structures. Overexpression of TRIM27 promotes cancer cell growth in vitro and tumor growth in nude mice, whereas knockdown of TRIM27 has opposite effects. Deficiency of TRIM27 significantly impairs dextran sulfate sodium (DSS)-induced STAT3 activation, inflammatory cytokine expression and colitis as well as azoxymethane (AOM)/DSS-induced colitis-associated cancer in mice. These findings reveal a retromer-dependent mechanism for regulation of STAT3 activation, inflammation, and inflammation-associated cancer development.

Aberrant and persistent activation of the transcription factor STAT3 has been found in various types of cancers. Here the authors identify TRIM27 as a positive regulator of IL-6-induced STAT3 activation through the formation of JAK1-STAT3 complex, thus impacting inflammation-induced colon cancer development.

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

OBJECTIVE

The tripartite motif-containing protein (TRIM) family is involved in important biological processes such as the cell cycle, cell apoptosis, and innate immunity of virus. This study aimed to investigate TRIM66 expression and its predictive role in non-small cell lung cancer (NSCLC) patients.

METHODS

We detected the expression levels of TRIM66 protein and TRIM66 mRNA in NSCLC tissues, and evaluated the prognostic role of TRIM66 in NSCLC.

RESULTS

TRIMM66 was highly expressed in NSCLC tissues compared with normal paracancerous tissues (P= 0.001). The high TRIM66 expression closely associated with lymph node metastasis and TNM stage in NSCLC patients (P< 0.05). Kaplan-Meier survival model indicated that survival time of NSCLC patients in the high TRIM66 expression group were markedly lower than those in the low expression group (P< 0.05). Cox regression analysis showed that high expression of TRIM66 is associated with poor prognosis in NSCLC patients.

CONCLUSION

TRIM66 can be serve as an important molecular marker for predicting the prognosis in NSCLC patients.

TRIM27 functions as an oncogene by activating epithelial-mesenchymal transition and p-AKT in colorectal cancer

Tripartite motif-containing 27 (TRIM27) belongs to the tripartite motif (TRIM) protein family and is involved in various malignant tumor processes. However, the function and mechanism of TRIM27 in colorectal cancer (CRC) remains to be elucidated. In the present study, the expression of TRIM27 was analyzed in CRC tissues and adjacent normal tissues by reverse transcription-quantitative polymerase chain reaction and immunohistochemistry. LoVo and HCT116 cell lines were then selected to further investigate the function of TRIM27 in the proliferation, invasion and metastasis of CRC in vitro and in vivo. Finally, the potential mechanism underlying the effects of TRIM27 in CRC was examined by western blotting. The results showed that TRIM27 was upregulated in CRC tissues, and the expression level of TRIM27 was significantly associated with tumor invasion, metastasis and prognosis. Following TRIM27 inhibition and overexpression in CRC cells, it was found that TRIM27 promoted cell proliferation, possibly via the inhibition of apoptosis and cell cycle regulation. TRIM27 also facilitated invasion and metastasis. Finally, it was observed that TRIM27 promoted epithelial-mesenchymal transition and activated phosphorylated AKT serine/threonine kinase in CRC cells. These results suggested that TRIM27 is an oncogenic protein in the progression of CRC, and may represent a novel target for CRC detection and therapy.

Controlling Directed Protein Interaction Networks in Cancer

Control theory is a well-established approach in network science, with applications in bio-medicine and cancer research. We build on recent results for structural controllability of directed networks, which identifies a set of driver nodes able to control an a-priori defined part of the network. We develop a novel and efficient approach for the (targeted) structural controllability of cancer networks and demonstrate it for the analysis of breast, pancreatic, and ovarian cancer. We build in each case a protein-protein interaction network and focus on the survivability-essential proteins specific to each cancer type. We show that these essential proteins are efficiently controllable from a relatively small computable set of driver nodes. Moreover, we adjust the method to find the driver nodes among FDA-approved drug-target nodes. We find that, while many of the drugs acting on the driver nodes are part of known cancer therapies, some of them are not used for the cancer types analyzed here; some drug-target driver nodes identified by our algorithms are not known to be used in any cancer therapy. Overall we show that a better understanding of the control dynamics of cancer through computational modelling can pave the way for new efficient therapeutic approaches and personalized medicine.

Role of tripartite motif protein 27 as a gametogenesis-related protein in human germ cells

BACKGROUND

The distribution and functional integrity of members of the tripartite motif (TRIM) protein family are essential for cell proliferation, development and apoptosis, and TRIM proteins have been linked to various cancers. To explore the diagnostic potential and mechanisms of TRIM27 in human spermatogenesis and oogenesis, we analyzed its localization pattern and putative roles in human testes and ovaries.

METHODS

TRIM27 mRNA and protein levels in human testes and ovaries were investigated using RT-PCR and western blotting, respectively. TRIM27 was abundantly transcribed in human testes and ovaries, particularly during the early stages of spermatogenesis, and localized in the nuclei of primary spermatocytes. Immunofluorescence also revealed a diffuse distribution in the cytoplasm of round spermatids, and the protein was abundant in ovary tissue during various stages of oogenesis development.

RESULTS

TRIM27 mRNA and protein was abundantly transcribed in male and female human germ cells by RT-PCR and western blotting in the human testes followed by the ovary. Immunohistochemical results revealed TRIM27 protein was abundant in the sex body of primary spermatocytes undergoing meiotic prophase during the first cycle of spermatogenesis. Moreover, Trim27 was diffusely localized in the cytoplasm of spermatids and round spermatids. Furthermore, TRIM27 was localized to both the nucleus and cytoplasm of human ovary cells.

CONCLUSIONS

TRIM27 as a gametogenesis-related protein could play multiple roles in the regulation of sex body formation and germ cell proliferation during spermatogenesis and oogenesis. The identification and characterization of TRIM27 enhances our understanding of the molecular mechanisms underpinning its functions, and provides insight into its potential role in the pathogenesis of germ cell differentiation and infertility.

SUMO pathway components as possible cancer biomarkers

SUMOylation is a key post-translational modification that regulates crucial cellular functions and pathological processes. Recently, Small Ubiquitin-related MOdifier (SUMO) modification has emerged as a fundamental route that may drive different steps of human tumorigenesis. Indeed, alteration in expression or activity of one of the different SUMO pathway components may completely subvert cellular properties through fine-tuning modulation of protein(s) involved in carcinogenic pathways, leading to altered cell proliferation, apoptosis resistance and metastatic potential. Here we describe some of the most interesting findings pointing to a clear link between SUMO pathway and human malignancies. Importantly, a putative role for SUMO enzymes to predict cancer behavior can be speculated, and thus the possible application of alterations in SUMO pathway components as tumor biomarkers is discussed.

Downregulation of TRIM27 expression inhibits the proliferation of ovarian cancer cells in vitro and in vivo

TRIM27 (tripartite motif-containing 27) was originally identified as a fusion partner with the RET (REarranged during transfection) proto-oncogene and is highly expressed in various tumor cells and tissues. However, the level of expression and function of TRIM27 in ovarian cancer remain unclear. Here we have measured the expression of TRIM27 in normal ovarian and fallopian tube epithelial cells and in ovarian serous carcinoma cells and correlated TRIM27 expression with clinical and pathological parameters. In addition, we detected the effect of TRIM27 knockdown on proliferation of ovarian cancer cells in cell culture and xenografts. The results demonstrated that TRIM27 was highly expressed in ovarian serous carcinoma cells, and TRIM27 expression was significantly correlated with metastasis and FIGO stage in ovarian serous carcinoma patients. Downregulation of TRIM27 expression suppressed the proliferation of ovarian cancer cells in cell culture and inhibited the growth of xenografts in nude mice. TRIM27 knockdown induced cell cycle arrest and apoptosis in ovarian cancer cells by upregulating the expression of p-P38 and downregulating the expression of p-AKT. Thus the present study suggests that TRIM27 could have important roles as an oncogene during the development of ovarian cancer and could serve as a diagnostic and therapeutic target.

Suppression of REV7 enhances cisplatin sensitivity in ovarian clear cell carcinoma cells

Human REV7 (also known as MAD2L2 and MAD2B) is involved in DNA repair, cell cycle regulation, gene transcription, and carcinogenesis. In this study, we evaluated the expression of REV7 in epithelial ovarian cancer (EOC) and analyzed the association between its expression and chemosensitivity in ovarian clear cell carcinoma (CCC) cells. Expression of REV7 in human EOC tissues was assessed by immunohistochemical staining. Expression was detected in the majority of EOCs (92.0%) with especially high levels of expression frequently observed in CCCs (73.5%) compared with that of non-CCCs (53.4%). Enhanced immunoreactivity to REV7 was associated with poor prognosis represented by reduced progression-free survival in advanced stage (stage II–IV) EOC as assessed using Kaplan–Meier curves and log–rank tests. The effects of REV7 knockdown on cell proliferation and chemosensitivity in CCC cells were also analyzed in vitro and in vivo. Knockdown of REV7 in CCC cells decreased cell proliferation without affecting cell cycle distribution. Additionally, the number of apoptotic cells and DNA damaged cells were increased after cisplatin treatment. In a nude mouse tumor xenograft model, inoculated REV7-knockdown tumors showed significantly reduced tumor volumes after cisplatin treatment compared with those of the control group. These findings indicate that depletion of REV7 enhances sensitivity to cisplatin treatment in CCC, suggesting that REV7 is a candidate molecular target in CCC management.

Activation of apoptotic pathway in normal, cancer ovarian cells by epothilone B

The epothilones, a new class of microtubule-targeting agents, seem to be a very promising alternative to the current strategy of cancer treatment. We have analyzed the aspects of epothilone B (Epo B) on cellular metabolism of tumor (OV-90) and normal (MM 14) ovarian cells. The observed effects were compared with those of paclitaxel (PTX), which is now a standard for the treatment of ovarian cancer. The results provide direct evidence that Epo B is considerably more cytotoxic to human OV-90 ovarian cancer cells than PTX. We have found, that antitumor efficacy of this new drug is related to its apoptosis-inducing ability, which was confirmed during measurements typical markers of the process. Epo B induced changes in morphology of cells, mitochondrial membrane potential and cytochrome c release. Also a slight increase of the intracellular calcium level was observed. Moreover, we have found that ROS production, stimulated by Epo B, is directly involved in the induction of apoptosis via mitochondrial pathway.