TRIM11 attenuates Treg cell differentiation by p62-selective autophagic degradation of AIM2.

Ubiquitination is an important protein modification that regulates diverse biological processes, including CD4+ T cell differentiation and functions. However, the function of most E3 ubiquitin ligases in CD4+ T cell differentiation and CD4+ T cell-mediated pathological diseases remains unclear. In this study, we find that tripartite motif-containing motif 11 (TRIM11) specifically negatively regulates regulatory T (Treg) cell differentiation in CD4+ T cells and promotes autoimmune disease development in an AIM2-dependent manner. Mechanistically, TRIM11 interacts with absent in melanoma 2 (AIM2) and promotes the selective autophagic degradation of AIM2 by inducing AIM2 ubiquitination and binding to p62 in CD4+ T cells. AIM2 attenuates AKT and FOXO1 phosphorylation, MYC signaling, and glycolysis, thereby promoting the stability of Treg cells during experimental autoimmune encephalomyelitis (EAE). Our findings suggest that TRIM11 serves as a potential target for immunotherapeutic intervention for dysregulated immune responses that lead to autoimmunity and cancers.

RNF157 attenuates CD4+ T cell-mediated autoimmune response by promoting HDAC1 ubiquitination and degradation.

Background: CD4+ T cells play an important role in body development and homeostasis. Quantitative and functional changes in CD4+ T cells result in abnormal immune responses, which lead to inflammation, cancer, or autoimmune diseases, such as multiple sclerosis (MS). Ubiquitination plays an essential role in the differentiation and functioning of CD4+ T cells. However, the function of several E3 ubiquitin ligases in CD4+ T cell differentiation and T cell-mediated pathological diseases remains unclear. Methods: RNA sequencing data were analyzed to identify the E3 ubiquitin ligases that participate in the pathogenesis of MS. Furthermore, conditional knockout mice were generated. Specifically, flow cytometry, qPCR, western blot, CO-IP and cell transfer adoptive experiments were performed. Results: In this study, we identified The RING finger 157 (RNF157) as a vital regulator of CD4+ T cell differentiation; it promoted Th1 differentiation but attenuated Th17 differentiation and CCR4 and CXCR3 expressions in CD4+ T cells, thereby limiting experimental autoimmune encephalomyelitis development. Mechanistically, RNF157 in CD4+ T cells targeted HDAC1 for K48-linked ubiquitination and degradation. Notably, RNF157 expression was significantly decreased and showed a significant negative correlation with RORγt expression in patients with MS. Conclusions: Our study highlights the critical role of RNF157 in regulating CD4+ T cell functions in autoimmune diseases and suggests RNF157 as a potential target in adaptive immune responses against MS and other autoimmune disorders.

Integrated tissue proteome and metabolome reveal key elements and regulatory pathways in cutaneous squamous cell carcinoma.

Cutaneous squamous cell carcinoma (CSCC) is a widespread malignancy but has a very low long-term survival rate for patients at the metastatic stage. Therefore, it is urgent to identify prognostic biomarkers for CSCC and improve our understanding of disease progression. Here we took advantage of a data-independent acquisition (DIA)-based nano liquid chromatography equipped with an orbitrap mass spectrometry (nLC-MS/MS) and ultraperformance LC coupled to a time-of-flight tandem MS (UPLC-TOF-MS/MS) technique to analyze cancer and corresponding noncancerous tissues from 20 CSCC patients for integrated proteomic and metabolomic analyses. Overall, 6241 tissue proteins were detected, while 136 proteins were significantly expressed in CSCC tissues. Further functional analysis revealed that various biological processes were highly enriched and participated in the pathogenesis of CSCC, especially DNA damage responses. Moreover, 641 named metabolites in total were identified, among which 181 were significantly changed in CSCC tissues. A total of 101 pathways were significantly enriched including apoptosis, autophagy, PI3K-Akt and mTOR signaling pathways. Interestingly, two pathways, protein digestion & absorption and platelet activation were both enriched in proteomic and metabolomic studies involving 5 proteins and 11 metabolites. Accordingly, a four-metabolite panel consisting of arachidonate, glutamine, glutamic acid, and proline (all area under the curve (AUC) values more than 0.9) was developed with a high accuracy (0.971) to distinguish the 20 detected cancer tissues from their noncancerous tissues. Collectively, our work highlighted the key elements and regulatory pathways involved in the pathogenesis of CSCC. More importantly, the present study not only provided potential biomarkers for the early diagnosis of CSCC, but also expanded our knowledge of the physiopathology of the disease. SIGNIFICANCE: CSCC is the second most common human cancer but has few treatment options and few sensitive biomarkers for diagnosis. Here we comprehensively revealed its molecular characteristics by performing integrated tissue proteomic and metabolomic analyses. Significantly distinct profiles and certain enriched pathways including DNA damage responses were identified as associated with CSCC. Moreover, protein digestion & absorption and platelet activation were both enriched in the proteome and metabolome. These identified molecular changes probably play significant roles in CSCC development. Finally, we developed a four-metabolite panel to distinguish CSCC with high accuracy. Overall, our data not only provided potential diagnostic biomarkers, but also extended knowledge on the pathogenesis of CSCC.

MicroRNA-495 confers inhibitory effects on cancer stem cells in oral squamous cell carcinoma through the HOXC6-mediated TGF-ß signaling pathway.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is associated with high morbidity and ranks sixth among malignancies worldwide. Increasing evidence suggests that microRNAs (miRNAs or miRs) play a critical role in regulating cancer stem cells (CSCs), which drive the proliferation and spread of OSCC. Therefore, based on the alteration of aberrantly expressed miR-495 and homeobox C6 (HOXC6) by Gene Expression Omnibus (GEO) analysis, we subsequently explore the potential effect of miR-495 on the progression of CSCs in OSCC. METHODS: After the isolation of CSCs from the clinical tissue samples of OSCC patients, the expression of miR-495 and HOXC6 was determined, followed by the validation of the relationship between miR-495 and HOXC6. Subsequently, gain- and loss-function approach was performed to detect the role of miR-495 and HOXC6 in cell proliferation, migration, invasion, cell cycle entry, apoptosis, and epithelial-mesenchymal transition (EMT) of CSCs in OSCC, as well as the tumor growth in vivo. RESULTS: HOXC6 was highly expressed while miR-495 was poorly expressed in OSCC. HOXC6 was verified to be a target gene of miR-495, and miR-495 could inhibit the activation of the TGF-ß signaling pathway. CSCs with miR-495 overexpression or HOXC6 silencing exhibited reversed EMT process; reduced abilities of proliferation, migration, and invasion; and promoted cell apoptosis in vitro. Moreover, inhibited tumor growth was observed in vivo after injection with miR-495 agomir or sh-HOXC6. In contrast, the downregulation of miR-495 showed an induced role in the progression of OSCC. CONCLUSION: These findings suggest that miR-495 may suppress HOXC6 to inhibit EMT, proliferation, migration, and invasion while promoting apoptosis of CSCs in OSCC by inhibiting the TGF-ß signaling pathway.

FZD8 Indicates a Poor Prognosis and Promotes Gastric Cancer Invasion and Metastasis via B-Catenin Signaling Pathway.

FZD8, a G protein-coupled receptor protein belonging to the Frizzled family, is considered to play an important role in cancer invasion and metastasis. However, the function of FZD8 in the invasion and metastasis of gastric cancer (GC) has not been elucidated. In this study, we first confirm that FZD8 protein expression was significantly upregulated in gastric cancer tissue and has a potential to be an independent predictor of poor prognosis for patients with GC. In vivo and in vitro evidences were provided that support the idea of FZD8 being able to suppress GC cell invasion and metastasis. Further studies show that FZD8 promotes the markers expression related to invasion and metastasis. FZD8 exerts biological function through the ß-catenin pathway which plays an important role in invasion and metastasis of gastric cancer cells. Finally, FZD8 could activate the ß-catenin pathway and its target gene's expression. In conclusion, our findings show that FZD8 promotes GC invasion and metastasis via the ß-catenin pathway.

MicroRNA-1305 Inhibits the Stemness of LCSCs and Tumorigenesis by Repressing the UBE2T-Dependent Akt-Signaling Pathway.

MicroRNAs (miRNAs) are involved in the maintenance of the cancer stem cell (CSC) phenotype by binding to genes and proteins that modulate cell proliferation and/or cell apoptosis. In our study, we aimed to investigate the role of miR-1305 in the proliferation and self-renewal of liver CSCs (LCSCs) via the ubiquitin-conjugating enzyme E2T (UBE2T)-mediated Akt-signaling pathway. Differentially expressed genes in human hepatocellular carcinoma (HCC) were obtained by in silico analysis. The relationship between miR-1305 and UBE2T was verified by dual luciferase reporter gene assay. qRT-PCR and western blot analysis were performed to determine the expression of UBE2T, the Akt-signaling pathway, and stemness-related factors in LCSCs. In addition, miR-1305 disrupted the activation of the Akt-signaling pathway by targeting UBE2T, and, ultimately, it repressed the sphere formation, colony formation, and proliferation, as well as tumorigenicity of LCSCs. In summary, miR-1305 targeted UBE2T to inhibit the Akt-signaling pathway, thereby suppressing the self-renewal and tumorigenicity of LCSCs. Those findings may provide an enhanced understanding of miR-1305 as a therapeutic target to limit the progression of LCSCs.

miR­21 inhibitor facilitates the anticancer activity of doxorubicin loaded nanometer in melanoma.

MicroRNA­21 (miR­21) is a potential therapeutic target for melanoma. Whether miR­21 inhibitor affects the anti­cancer activity of doxorubicin assisted by c(RGDyK)­modified liposome (DLN) in melanoma and the underlying mechanisms are largely unknown. In this study, in vitro and animal models were used to explore the effect of DLN combined with miR­21 inhibitor on melanoma cells. The data demonstrated that treatment with 5 µl DLN (final concentration of doxorubicin 5 mg/ml) for 72 h effectively inhibited melanoma cell growth (~75% inhibition). The experiments were then divided into five groups: Control group, vector group, DLN group, miR­21 inhibitor group and miR­21 inhibitor + DLN group. Compared with the control group, DLN (5 µl) or miR­21 inhibitor significantly reduced migration and invasion of melanoma cells, promoted apoptosis and arrested cells at the G1 phase. Notably, the combined application of DLN with miR­21 inhibitor further promoted the anti­cancer effects (reducing migration and invasion of melanoma cells, promoting apoptosis and arresting cells at G1 phase) compared with individual application of DLN or miR­21 inhibitor. Mechanically, DLN did not function by reducing miR­21 expression, whereas DLN and miR­21 inhibitor downregulated B­cell lymphoma-2 (BCL­2) expression, and facilitated BCL­2­associated X protein (Bax) and P53 expression in melanoma cells. DLN and miR­21 inhibitor together displayed stronger effects on Bcl­2, Bax and P53 expression that each alone. In vivo data further demonstrated that DLN inhibited tumor growth further than a similar dose of doxorubicin only. Furthermore, miR­21 inhibitor and DLN exerted the optimal anti­cancer effect compared with single application of DLN or miR­21 inhibitor. Together, the findings demonstrated miR­21 inhibitor facilitated the anti­cancer activity of DLN in melanoma, and the mechanisms involved Bcl­2, Bax and P53 expression.

c[RGDyk]-coated liposomes loaded with adriamycin and miR-21 mimics inhibit the growth of hepatoma cell line SMCC-7721 via up-regulating Bax and p53.

BACKGROUND: This study was conducted to investigate the effects of c[RGDyk]-coated liposomes loaded with Adriamycin (nanodrug) and miR-21 mimics on hepatoma cell line SMCC-7721. METHODS: SMCC-7721 cells were divided into five groups: control (receiving no treatment), nanodrug, miR-21 mimics + nanodrug and miR-21 mimics and empty vector. The concentration and duration of treatments were determined using the MTT assay. Cell apoptosis was detected using flow cytometer. The expression of Bax, Bcl-2 and p53 was measured using qPCR and Western blot analysis. RESULTS: MTT showed that the nanodrug inhibited cell proliferation. Nanodrug and miR-21 led to cell arrest at S phase and apoptosis. qPCR showed that cells treated with nanodrug and miR-21 increased the expression of Bax and p53. Western blot analysis indicated that Bcl-2 expression was significantly reduced. CONCLUSIONS: Our work demonstrates that nanodrug and miR-21 have inhibitory effect on SMCC-7721 cells via up-regulating Bax and p53.

Advances in the T7 phage display system (Review).

The present review describes the advantages and updated applications of the T7 phage display system in bioscience and medical science. Current phage display systems are based on various bacteriophage vectors, including M13, T7, T4 and f1. Of these, the M13 phage display is the most frequently used, however, the present review highlights the advantages of the T7 system. As a phage display platform, M13 contains single­stranded DNA, while the T7 phage consists of double­stranded DNA, which exhibits increased stability and is less prone to mutation during replication. Additional characteristics of the T7 phage include the following: The T7 phage does not depend on a protein secretion pathway in the lytic cycle; expressed peptides and proteins are usually located on the C­terminal region of capsid protein gp10B, which avoids problems associated with steric hindrance; and T7 phage particles exhibit high stability under various extreme conditions, including high temperature and low pH, which facilitates effective high­throughput affinity elutriation. Recent applications of the T7 phage display system have been instrumental in uncovering mechanisms of molecular interaction, particularly in the fields of antigen discovery, vaccine development, protein interaction, and cancer diagnosis and treatment.