Expression of ribosome-binding protein 1 correlates with shorter survival in Her-2 positive breast cancer

Mechanism Analysis of Metabolic Fatty Liver on Largemouth bass (Micropterus salmoides) Based on Integrated Lipidomics and Proteomics

Metabolic fatty liver disease caused by high-starch diet restricted the intensive and sustainable development of carnivorous fish such as largemouth bass. In this study, the combination liver proteomic and lipidomic approach was employed to investigate the key signaling pathways and identify the critical biomarkers of fatty liver in largemouth bass. Joint analysis of the correlated differential proteins and lipids revealed nine common metabolic pathways; it was determined that FABP1 were significantly up-regulated in terms of transporting more triglycerides into the liver, while ABCA1 and VDAC1 proteins were significantly down-regulated in terms of preventing the transport of lipids and cholesterol out of the liver, leading to triglyceride accumulation in hepatocyte, eventually resulting in metabolic fatty liver disease. The results indicate that FABP1, ABCA1 and VDAC1 could be potential biomarkers for treating metabolic fatty liver disease of largemouth bass.

CircVPS13C promotes pituitary adenoma growth by decreasing the stability of IFITM1 mRNA via interacting with RRBP1

CircRNAs play important roles in a variety of biological processes by acting as microRNA sponges and protein scaffolds or by encoding functional proteins. However, their functions and underlying mechanisms remain largely unknown. Distinctive circRNA patterns were explored by comparing nonfunctioning pituitary adenomas (NFPAs) and normal pituitary tissues with a circRNA array. The biological functions of selected circRNAs were determined in vitro and in vivo. RNA-seq and circRNA pulldown assays were applied to investigate the underlying mechanisms. The circRNA profile of NFPAs is tremendously different from that of normal pituitary tissues. CircVPS13C is significantly upregulated in NFPA samples and cell lines. Gain- and loss-of-function experiments demonstrate that silencing circVPS13C inhibits the proliferation of pituitary tumor cells in vitro and in vivo. Mechanistically, circVPS13C silencing increases the expression of IFITM1 and subsequently activates its downstream genes involved in MAPK- and apoptosis-associated signaling pathways. Rescue experiments show that IFITM1 overexpression partly reverses the biological effects of circVPS13C. Further studies reveal that circVPS13C inhibits IFITM1 expression through a novel mechanism mainly by competitively interacting with RRBP1, a ribosome-binding protein of the endoplasmic reticulum membrane, and thereby alleviating the stability of IFITM1 mRNA. Clinically, circVPS13C expression is markedly higher in high-risk NFPA samples and is downregulated in patient serum 7 days post-transsphenoidal adenoma resection. Our findings suggest that circVPS13C is a critical regulator in the proliferation and development of NFPAs through a novel mechanism, whereby regulating mRNA stability via interacting with ribosome-binding proteins on the endoplasmic reticulum membrane.

A novel bioavailable curcumin-galactomannan complex modulates the genes responsible for the development of chronic diseases in mice: A RNA sequence analysis

BACKGROUND

Chronic diseases or non-communicable diseases are a major burden worldwide due to the lack of highly efficacious treatment modalities and the serious side effects associated with the available therapies.

PURPOSE/STUDY DESIGN

A novel self-emulsifying formulation of curcumin with fenugreek galactomannan hydrogel scaffold as a water-dispersible non-covalent curcumin-galactomannan molecular complex (curcumagalactomannosides, CGM) has shown better bioavailability than curcumin and can be used for the prevention and treatment of chronic diseases. However, the exact potential of this formulation has not been studied, which would pave the way for its use for the prevention and treatment of multiple chronic diseases.

METHODS

The whole transcriptome analysis (RNAseq) was used to identify differentially expressed genes (DEGs) in the liver tissues of mice treated with LPS to investigate the potential of CGM on the prevention and treatment of chronic diseases. Expression analysis using DESeq2 package, GO, and pathway analysis of the differentially expressed transcripts was performed using UniProtKB and KEGG-KAAS server.

RESULTS

The results showed that 559 genes differentially expressed between the liver tissue of control mice and CGM treated mice (100 mg/kg b.wt. for 14 days), with adjusted p-value below 0.05, of which 318 genes were significantly upregulated and 241 were downregulated. Further analysis showed that 33 genes which were upregulated (log2FC > 8) in the disease conditions were significantly downregulated, and 32 genes which were downregulated (log2FC < -8) in the disease conditions were significantly upregulated after the treatment with CGM.

CONCLUSION

Overall, our study showed CGM has high potential in the prevention and treatment of multiple chronic diseases.

USP35 mitigates endoplasmic reticulum stress-induced apoptosis by stabilizing RRBP1 in non-small cell lung cancer

Deubiquitinating enzymes (DUBs) serve to maintain cellular homeostasis via protein ubiquitination and exert diverse regulatory functions in cancers and other diseases. Much progress has been made in characterizing biological roles of DUBs over the decades, yet the specific functions of many subclass members remain largely unexplored. It was not until recent years that the role of ubiquitin‐specific‐processing protease 35 (USP35) in cancers began to be understood. Here, we focus on delineating the roles and underlying mechanisms of USP35 in non‐small cell lung cancer (NSCLC). The isobaric tags for relative and absolute quantitation (iTRAQ) comparative proteomic approach were employed to identify differentially expressed proteins (DEPs) in H1299 cells induced by USP35 overexpression or silencing. Among the potential interactome of USP35, ribosome‐binding protein 1 (RRBP1), a membrane‐bound protein in endoplasmic reticulum (ER), captured our attentions. RRBP1 expression was found to positively correlate with USP35 levels in both genetically modified cells and human NSCLC tissues. Concordantly, both RRBP1 expression and USP35 expression were found to positively correlate with poor prognoses in lung adenocarcinoma patients. At the molecular level, USP35 was verified to directly interact with RRBP1 to prevent it from proteasomal‐dependent degradation. Functionally, USP35 alleviated ER stress‐induced cell apoptosis by stabilizing RRBP1 in NSCLC cells. Collectively, these findings indicate that USP35 plays a critical role in resisting ER stress‐induced cell death through deubiquitinating RRBP1, hence providing a rationale to target the USP35‐RRBP1 axis as an alternative therapeutic option for NSCLC.

Hypomethylated RRBP1 Potentiates Tumor Malignancy and Chemoresistance in Upper Tract Urothelial Carcinoma

Ribosome-binding protein 1 (RRBP1) is a potential oncogene in several cancer types. However, the correlation between RRBP1 expression and the prognosis of patients with upper tract urothelial carcinoma (UTUC) remains unclear. In this study, we identified that RRBP1 is associated with carcinogenesis and metastasis in UTUC using a methylation profiling microarray. High correlations between RRBP1 and cancer stages, nodal metastasis status, molecular subtypes, and prognosis in bladder urothelial cancer (BLCA) were found. Aberrant DNA methylation in the gene body region of RRBP1 was determined in UTUC tissues by methylation-specific PCR. RRBP1 expression was significantly increased in UTUC tissues and cell lines, as determined by real-time PCR and immunohistochemistry. RRBP1 depletion significantly reduced BFTC909 cell growth induced by specific shRNA. On the other hand, molecular subtype analysis showed that the expression of RRBP1 was associated with genes related to cell proliferation, epithelial-mesenchymal transition, and basal markers. A patient-derived organoid model was established to analyze patients' responses to different drugs. The expression of RRBP1 was related to chemoresistance. Taken together, these results provide the first evidence that RRBP1 gene body hypomethylation predicts RRBP1 high expression in UTUC. The data highlight the importance of RRBP1 in UTUC malignancy and chemotherapeutic tolerance.

Proteomic Analysis of Hepatocellular Carcinoma Tissues With Encapsulation Shows Up-regulation of Leucine Aminopeptidase 3 and Phosphoenolpyruvate Carboxykinase 2

BACKGROUND/AIM

Cancer is the most fatal disease worldwide whose most lethal characteristics are invasion and metastasis. Hepatocellular carcinoma (HCC) is one of the most fatal cancers worldwide. HCC often shows encapsulation, which is related to better prognosis. In this study, proteomic analysis of HCC tissues with and without encapsulation was performed, in order to elucidate the factors which play important roles in encapsulation.

MATERIALS AND METHODS

Five HCC tissues surrounded by a capsule and five HCC tissues which broke the capsule were obtained from patients diagnosed with HCC who underwent surgical liver resection. Protein samples from these tissues were separated by two-dimensional gel electrophoresis (2-DE), and the protein spots whose expression was different between encapsulated and non-encapsulated HCC tissues were identified through gel imaging analysis software. The selected protein spots were analyzed and identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

RESULTS

Two-DE analysis showed 14 spots whose expression was different between encapsulated and non-encapsulated HCC tissues. Of these, 9 were up-regulated and 5 were down-regulated in HCC tissues without encapsulation. The validation by Western blot confirmed that leucine aminopeptidase 3 (LAP3) and phosphoenolpyruvate carboxykinase mitochondrial (PCK2) were up-regulated significantly in HCC tissues with a capsule, compared to HCC tissues that broke the capsule.

CONCLUSION

These findings suggest that LAP3 and PCK2 could be factors responsible for the maintenance of encapsulation in HCC tissues.

Isobaric Tags for Relative and Absolute Quantitation in Proteomic Analysis of Potential Biomarkers in Invasive Cancer, Ductal Carcinoma In Situ, and Mammary Fibroadenoma

OBJECTIVES

Breast malignancy is a serious threat to women's health around the world. Following the rapid progress in the field of cancer diagnostics and identification of pathological markers, breast tumor treatment methods have been greatly improved. However, for invasive, ductal carcinomas and mammary fibroadenoma, there is an urgent demand for better breast tumor-linked biomarkers. The current study was designed to identify diagnostic and/or therapeutic protein biomarkers for breast tumors.

METHODS

A total of 140 individuals were included, comprising 35 healthy women, 35 invasive breast cancers (IBC), 35 breast ductal carcinomas in situ (DCIS), and 35 breast fibroadenoma patients. Isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis was employed to characterize differentially expressed proteins for potential biomarkers in IBC, DCIS, and fibroadenomas by comparisons with their matched adjacent tissues and/or normal breast tissues. The public databases Metascape and String were used for bioinformatic analyses.

RESULTS

Using the proteomics approach, we identified differentially expressed proteins in tissues of different breast tumors compared to normal/adjacent breast tissues, including 100 in IBC, 52 in DCIS, and 44 in fibroadenoma. Among the 100 IBC differentially expressed proteins, 37 were found to be specific to this type of cancer only. Additionally, four proteins were specifically expressed in DCIS and four in fibroadenoma. Compared to corresponding adjacent tissues and normal breast tissues, 18 step-changing proteins were differentially expressed in IBC, 14 in DCIS, and 13 in fibroadenoma, respectively. Compared to DCIS and normal breast tissues, 65 proteins were differentially expressed in IBC with growing levels of malignancy.

CONCLUSIONS

The identified potential protein biomarkers may be used as diagnostic and/or therapeutic targets in breast tumors.

Ribosome Binding Protein 1 Correlates with Prognosis and Cell Proliferation in Bladder Cancer

Introduction

Ribosome binding protein 1 (RRBP1) is reported to be correlated with tumor formation and progression. However, the role of RRBP1 in bladder cancer is unclear. In this study, we aimed to investigate the expression of RRBP1 and its influence on cell proliferation in bladder cancer.

Methods

Quantification real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC) were used to detect the expression levels of RRBP1 in 138 bladder cancer and matched adjacent normal bladder tissues. Then, the clinical significance of RRBP1 in bladder cancer was evaluated. The effect of RRBP1 on cell proliferation and its potential mechanism were further explored.

Results

Results show that the mRNA levels of RRBP1 in bladder cancer were significantly higher compared with those in normal tissues (P< 0.001). IHC results show the high-expression rate of RRBP1 in bladder cancer was 68.8%, which was significantly greater than those in normal tissues (40.6%, P< 0.001). RRBP1 high-expression was significantly associated with differentiation, T stage and lymph node metastasis in bladder cancer (P< 0.05). The overall survival time of patients with RRBP1 high-expression was significantly reduced compared to those with RRBP1 low-expression. Moreover, RRBP1 overexpression significantly promoted cell proliferation, which was correlated with Smad1/Smad3/TGF-β1 signal pathway.

Conclusion

RRBP1 high-expression correlates with prognosis and promotes cell proliferation in bladder cancer, which could be a potential biomarker.

Correlation between reticulum ribosome-binding protein 1 (RRBP1) overexpression and prognosis in cervical squamous cell carcinoma

Our purpose was to evaluate the correlation between endoplasmic reticulum ribosomal binding protein 1 (RRBP1) expression in cervical squamous cell carcinoma (CSCC) and poor patient prognosis. RRBP1 is a nascent transporter that is situated on the rough endoplasmic reticulum (ER). It adjusts to the secretion of proteins in cells and alleviates ER stress, thus stimulating cell proliferation. An immunohistochemical (IHC) study was conducted to detect the expression level of RRBP1 on 96 CSCC tissue samples. Western blot and Quantitative real-time polymerase chain reaction (qRT-PCR) were performed to compare the expression levels of RRBP1 in cervical squamous cell carcinoma with healthy cervical tissues. An overexpression of RRBP1 was observed in CSCC tissues, and the expression level was associated with FIGO stage (Stage I vs. II: 52.6% vs. 74.1%, p = 0.030), and lymph node metastasis (No vs. Yes: 61.5% vs. 92.3%, p = 0.031) but not patient age and tissue differentiation. Univariate survival analysis indicated that prognosis was associated with the expression level of RRBP1 and tissue differentiation and lymph node metastasis. Analysis of the multi-factor survival Cox model proved that RRBP1 was an independent prognostic factor. In conclusion, compared with healthy cervical tissues, RRBP1 was overexpressed in CSCC tissues, illustrating that RRBP1 may be a new biomarker for the diagnosis of CSCC. The study on RRBP1 may contribute to exploring the pathogenesis of CSCC and may also guide targeted therapy for CSCC in the future.

Mass spectrometry proteomics reveals a function for mammalian CALCOCO1 in MTOR-regulated selective autophagy

Macroautophagy/autophagy is suppressed by MTOR (mechanistic target of rapamycin kinase) and is an anticancer target under active investigation. Yet, MTOR-regulated autophagy remains incompletely mapped. We used proteomic profiling to identify proteins in the MTOR-autophagy axis. Wild-type (WT) mouse cell lines and cell lines lacking individual autophagy genes (Atg5 or Ulk1/Ulk2) were treated with an MTOR inhibitor to induce autophagy and cultured in media with either glucose or galactose. Mass spectrometry proteome profiling revealed an elevation of known autophagy proteins and candidates for new autophagy components, including CALCOCO1 (calcium binding and coiled-coil domain protein 1). We show that CALCOCO1 physically interacts with MAP1LC3C, a key protein in the machinery of autophagy. Genetic deletion of CALCOCO1 disrupted autophagy of the endoplasmic reticulum (reticulophagy). Together, these results reveal a role for CALCOCO1 in MTOR-regulated selective autophagy. More generally, the resource generated by this work provides a foundation for establishing links between the MTOR-autophagy axis and proteins not previously linked to this pathway. Abbreviations: ATG: autophagy-related; CALCOCO1: calcium binding and coiled-coil domain protein 1; CALCOCO2/NDP52: calcium binding and coiled-coil domain protein 2; CLIR: MAP1LC3C-interacting region; CQ: chloroquine; KO: knockout; LIR: MAP1LC3-interacting region; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MEF: mouse embryonic fibroblast; MLN: MLN0128 ATP-competitive MTOR kinase inhibitor; MTOR: mechanistic target of rapamycin kinase; reticulophagy: selective autophagy of the endoplasmic reticulum; TAX1BP1/CALCOCO3: TAX1 binding protein 1; ULK: unc 51-like autophagy activating kinase; WT: wild-type.

Compound C enhances the anticancer effect of aspirin in HER-2-positive breast cancer by regulating lipid metabolism in an AMPK-independent pathway

Various clinical studies have determined that aspirin shows anticancer effects in many human malignant cancers, including human epidermal growth factor receptor-2 (HER-2)-positive breast cancer. However, the anti-tumor mechanism of aspirin has not been fully defined. The aim of this study was to determine the role of Compound C in enhancing the anticancer effect of aspirin. HER-2-positive breast cancer cell lines were treated with aspirin with or without Compound C pre-treatment; their phenotypes and mechanisms were then analyzed in vitro and in vivo. Aspirin exhibited anticancer effects in HER-2-positive breast cancer by inhibiting cell growth and inducing apoptosis through the activation of AMP-activated protein kinase (AMPK). Unexpectedly, pre-treatment with Compound C, a widely used AMPK inhibitor, induced robust anticancer effects in cells compared to aspirin monotherapy. This anticancer effect was not distinct in HER-2 negative breast cancer MDA-MB-231 cells and may be due to the inhibition of lipid metabolism mediated by c-myc. Besides, c-myc re-expression or palmitic acid supply could partially restored cell proliferation. Aspirin exhibits anticancer effects in HER-2-positive breast cancer by regulating lipid metabolism mediated by c-myc, and Compound C strengthens these effects in an AMPK-independent manner. Our results potentially provide a novel therapeutic strategy exploiting combined aspirin and Compound C therapy for HER-2-positive breast cancer, which acts by reducing de novo lipid synthesis.

Expression of RRBP1 in epithelial ovarian cancer and its clinical significance

Hematopoietic pre-B cell leukemia transcription factor (PBX)-interacting protein (RRBP1) has been shown to participate in various aspects of malignancies. The clinical significance of RRBP1 and its involvement in the epithelial ovarian cancer have yet to be studied. The aim of the present study was to investigate the expression of RRBP1 in epithelial ovarian cancer (EOC) and its relationship with clinical characteristics and prognosis. We evaluated the mRNA and protein expression levels of RRBP1 by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting (n=45). Immunohistochemistry and data analysis were used to examine the relationship between the expression level of RRBP1 and the clinicopathological features and prognosis of epithelial ovarian cancer. RRBP1 was highly expressed in EOC (P<0.001). The specimens were obtained from 108 patients undergoing surgery to treat epithelial ovarian cancer. RRBP1 expression was obviously related to Federation International of Gynecologie and Obstetrigue (FIGO) stage (P<0.001), histological grade (P=0.021), histological type (P=0.004), and lymph node metastasis (P=0.012) but was not related to patient age (P=0.385) or preoperative carbohydrate antigen125 (CA125) level (P=0.238). Univariate analysis showed that the prognosis of the epithelial ovarian cancer patients was related to the age of the patients, the FIGO stage, and the expression level of RRBP1 (P<0.05). Patients with higher RRBP1 expression had significantly worse overall survival (OS) (P=0.003) and disease-free survival (DFS) (P<0.001). Multivariate survival analysis proved that RRBP1 was an independent predictor of OS (P=0.003) and DFS (P<0.001). RRBP1 plays an important role in predicting the prognosis of EOC. These results show that RRBP1 is a potential target for the treatment of epithelial ovarian cancer.

RRBP1 is highly expressed in prostate cancer and correlates with prognosis

Objective: Recently, ribosome binding protein 1 (RRBP1) is reported to be involved in tumorigenesis. However, the expression and clinical significance of RRBP1 in prostate cancer (PCa) remains unknown. This study is aimed to investigate the expression and clinical significance of RRBP1 in PCa.

Materials and methods: RRBP1 expression was firstly detected in 6 cases of PCa and matched adjacent non-cancerous prostate tissues by reverse transcription-quantitative PCR (RT-qPCR) and Western blot. Then, RRBP1 expression was further detected in 127 cases of PCa and 40 cases of non-cancerous prostate tissues by immunohistochemistry (IHC). The relationship of RRBP1 with clinical-pathological characters and patients’ prognosis was analyzed in PCa.

Results: RT-qPCR and Western blot analysis showed that RRBP1 expression levels in PCa tissues were significantly higher compared with those in matched adjacent non-cancerous prostate tissues. IHC results shown that the high-expression rate of RRBP1 in PCa was 69.3%, which was significantly greater than those in non-cancerous prostate tissues (15.0%, P<0.001). RRBP1 expression was significantly associated with T stage, lymph node metastasis, PSA and Gleason score in PCa. Survival analysis indicated that patients with RRBP1 low-expression presented longer survival time compared with those with RRBP1 high-expression. Moreover, RRBP1 as well as T stage, lymph node metastasis and Gleason score could serve as independent prognostic factors in PCa.

Conclusion: RRBP1 is highly expressed in PCa and correlates with prognosis, which may serve as a potential biomarker in PCa.

RRBP1 overexpression is associated with progression and prognosis in endometrial endometrioid adenocarcinoma

Background

Currently, ribosome-binding protein 1 (RRBP1) is considered to be a novel oncogene that is overexpressed in colorectal cancer, lung cancer, mammary cancer, esophageal cancer and other carcinomas. However, the relationship between RRBP1 and endometrioid-type endometrial carcinoma (EC) remains unknown. Our purpose is to explore the function of RRBP1 in endometrioid-type endometrial carcinoma.

Methods

We investigated the expression of RRBP1 protein by immunohistochemistry on paraffin-embedded surgical specimens from one hundred thirty patients with endometrioid-type endometrial carcinoma. We also evaluated the differences in RRBP1 expression between endometrial cancer samples (n = 35) and normal endometrial tissues (n = 19) by western blotting.

Results

RRBP1 was more highly expressed in endometrial cancer samples than in normal samples (P < 0.05). High levels of expression of RRBP1 were strongly correlated with pathological features, such as the Federation of Gynecology and Obstetrics (FIGO) stage, histological grade, depth of myometrial invasion and lymph node metastasis (P < 0.05). Furthermore, RRBP1 expression was an independent prognostic factor for overall survival (OS) and disease-free survival (DFS) in patients with EC (both P < 0.05).

Conclusion

This experiment identifies the utility of RRBP1 in predicting EC prognosis, revealing that it may be a potential target for therapeutics of EC.

Loss of conserved ubiquitylation sites in conserved proteins during human evolution

Ubiquitylation of lysine residues in proteins serves a pivotal role in the efficient removal of misfolded or unused proteins and in the control of various regulatory pathways by monitoring protein activity that may lead to protein degradation. The loss of ubiquitylated lysines may affect the ubiquitin‑mediated regulatory network and result in the emergence of novel phenotypes. The present study analyzed mouse ubiquitylation data and orthologous proteins from 62 mammals to identify 193 conserved ubiquitylation sites from 169 proteins that were lost in the Euarchonta lineage leading to humans. A total of 8 proteins, including betaine homocysteine S‑methyltransferase, clin and CBS domain divalent metal cation transport mediator 3, ribosome‑binding protein 1 and solute carrier family 37 member 4, lost 1 conserved lysine residue, which was ubiquitylated in the mouse ortholog, following the human‑chimpanzee divergence. A total of 17 of the lost ubiquitylated lysines are also known to be modified by acetylation and/or succinylation in mice. In 8 cases, a novel lysine evolved at positions flanking the lost conserved lysine residues, potentially as a method of compensation. We hypothesize that the loss of ubiquitylation sites during evolution may lead to the development of advantageous phenotypes, which are then fixed by selection. The ancestral ubiquitylation sites identified in the present study may be a useful resource for investigating the association between loss of ubiquitylation sites and the emergence of novel phenotypes during evolution towards modern humans.

Expression and significance of RRBP1 in esophageal carcinoma

Objective

This study was to investigate the expression and clinical significance of RRBP1 in esophageal carcinoma.

Materials and methods

RRBP1 expression was detected in 120 esophageal carcinoma and matched adjacent normal tissues, and the relationship of RRBP1 with clinicopathological characteristics and prognosis was analyzed.

Results

RRBP1 was highly expressed in esophageal carcinoma tissues compared with matched adjacent normal tissues (P<0.05). Moreover, RRBP1 expression was associated with T stage, lymph node metastasis, and TNM stage in esophageal carcinoma (P<0.05). Survival analysis revealed that RRBP1, T stage, lymph node metastasis, and TNM stage were significantly associated with patients’ prognosis.

Conclusion

RRBP1 is highly expressed in esophageal carcinoma and can serve as a potential biomarker to predict patients’ prognosis.

PSAT1 is regulated by ATF4 and enhances cell proliferation via the GSK3β/β-catenin/cyclin D1 signaling pathway in ER-negative breast cancer

Background

A growing amount of evidence has indicated that PSAT1 is an oncogene that plays an important role in cancer progression and metastasis. In this study, we explored the expression and function of PSAT1 in estrogen receptor (ER)-negative breast cancer.

Method

The expression level of PSAT1 in breast cancer tissues and cells was analyzed using real-time-PCR (RT-PCR), TCGA datasets or immunohistochemistry (IHC). The overall survival of patients with ER-negative breast cancer stratified by the PSAT1 expression levels was evaluated using Kaplan-Meier analysis. The function of PSAT1 was analyzed using a series of in vitro assays. Moreover, a nude mouse model was used to evaluate the function of PSAT1 in vivo. qRT-PCR and western blot assays were used to evaluate gene and protein expression, respectively, in the indicated cells. In addition, we demonstrated that PSAT1 was activated by ATF4 by chromatin immunoprecipitation (ChIP) assays.

Results

mRNA expression of PSAT1 was up-regulated in ER-negative breast cancer. A tissue microarray that included 297 specimens of ER-negative breast cancer was subjected to an immunohistochemistry assay, which demonstrated that PSAT1 was overexpressed and predicted a poor clinical outcome of patients with this disease. Our data showed that PSAT1 promoted cell proliferation and tumorigenesis in vitro and in vivo. We further found that PSAT1 induced up-regulation of cyclin D1 via the GSK3β/β-catenin pathway, which eventually led to the acceleration of cell cycle progression. Furthermore, ATF4 was also overexpressed in ER-negative breast cancers, and a positive correlation between the ATF4 and PSAT1 mRNA levels was observed in ER-negative breast cancers. We further demonstrated that knockdown of ATF4 by siRNA reduced PSAT1 expression. Finally, chromatin immunoprecipitation (ChIP) assays showed that PSAT1 was a target of ATF4.

Conclusions

PSAT1, which is overexpressed in ER-negative breast cancers, is activated by ATF4 and promotes cell cycle progression via regulation of the GSK3β/β-catenin/cyclin D1 pathway.

Electronic supplementary material

The online version of this article (doi: 10.1186/s13046-017-0648-4) contains supplementary material, which is available to authorized users.

Expression profile of rrbp1 genes during embryonic development and in adult tissues of Xenopus laevis

Recent studies suggest that ribosome-binding protein 1 (RRBP1) is involved in multiple diseases such as tumorigenesis and cardiomyopathies. However, its function during embryonic development remains largely unknown. We searched Xenopus laevis database with human RRBP1 protein sequence and identified two cDNA sequences encoding Xenopus orthologs of RRBP1 including rrbp1a (NM_001089623) and rrbp1b (NM_001092468). Both genes were firstly detected at blastula stage 8 with weak signals in animal hemisphere by whole mount in situ hybridization. Evident expression of rrbp1 was mainly detected in cement gland and notochord at neurula and tailbud stages. Heart expression of rrbp1 was detected at stage 36. RT-PCR results indicated that very weak expression of rrbp1a was firstly detected in oocytes, followed by increasing expression until stage 39. Differently, very weak expression of rrbp1b was firstly observed at stage 2, and then maintained at a lower level to stage 17 followed by an intense expression from stages 19-39. Moreover, both expression profiles were also different in adult tissues. This study reports Xenopus rrbp1 expression during early embryonic development and in adult tissues. Our study will facilitate the functional analysis of Rrbp1 family during embryonic development.

ALK oncoproteins in atypical inflammatory myofibroblastic tumours: novel RRBP1-ALK fusions in epithelioid inflammatory myofibroblastic sarcoma

ALK oncogenic activation mechanisms were characterized in four conventional spindle-cell inflammatory myofibroblastic tumours (IMT) and five atypical IMT, each of which had ALK genomic perturbations. Constitutively activated ALK oncoproteins were purified by ALK immunoprecipitation and electrophoresis, and were characterized by mass spectrometry. The four conventional IMT had TPM3/4-ALK fusions (two cases) or DCTN1-ALK fusions (two cases), whereas two atypical spindle-cell IMT had TFG-ALK and TPM3-ALK fusion in one case each, and three epithelioid inflammatory myofibroblastic sarcomas had RANBP2-ALK fusions in two cases, and a novel RRBP1-ALK fusion in one case. The epithelioid inflammatory myofibroblastic sarcoma with RRBP1-ALK fusion had cytoplasmic ALK expression with perinuclear accentuation, different from the nuclear membranous ALK localization in epithelioid inflammatory myofibroblastic sarcomas with RANBP2-ALK fusions. Evaluation of three additional uncharacterized epithelioid inflammatory myofibroblastic sarcomas with ALK cytoplasmic/perinuclear- accentuation expression demonstrated RRBP1-ALK fusion in two cases. These studies show that atypical spindle-cell IMT can utilize the same ALK fusion mechanisms described previously in conventional IMT, whereas in clinically aggressive epithelioid inflammatory myofibroblastic sarcoma we identify a novel recurrent ALK oncogenic mechanism, resulting from fusion with the RRBP1 gene. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Proteomic Analysis of the Peri-Infarct Area after Human Umbilical Cord Mesenchymal Stem Cell Transplantation in Experimental Stroke

Among various therapeutic approaches for stroke, treatment with human umbilical cord mesenchymal stem cells (hUC-MSCs) has acquired some promising results. However, the underlying mechanisms remain unclear. We analyzed the protein expression spectrum of the cortical peri-infarction region after ischemic stroke followed by treatment with hUC-MSCs, and found 16 proteins expressed differentially between groups treated with or without hUC-MSCs. These proteins were further determined by Gene Ontology term analysis and network with CD200-CD200R1, CCL21-CXCR3 and transcription factors. Three of them: Abca13, Grb2 and Ptgds were verified by qPCR and ELISA. We found the protein level of Abca13 and the mRNA level of Grb2 consistent with results from the proteomic analysis. Finally, the function of these proteins was described and the potential proteins that deserve to be further studied was also highlighted. Our data may provide possible underlying mechanisms for the treatment of stroke using hUC-MSCs.

Comprehensive Analysis of in Vivo Phosphoproteome of Mouse Liver Microsomes

Protein phosphorylation at serine, threonine, and tyrosine residues are some of the most widespread reversible post-translational modifications. Microsomes are vesicle-like bodies, not ordinarily present within living cells, which form from pieces of the endoplasmic reticulum (ER), plasma membrane, mitochondria, or Golgi apparatus of broken eukaryotic cells. Here we investigated the total phosphoproteome of mouse liver microsomes (MLMs) using TiO2 enrichment of phosphopeptides coupled to on-line 2D-LC-MS/MS. In total, 699 phosphorylation sites in 527 proteins were identified in MLMs. When compared with the current phosphoSitePlus database, 155 novel phosphoproteins were identified in MLM. The distributions of phosphosites were 89.4, 8.0, and 2.6% for phosphoserine, phosphotheronine, and phosphotyrosine, respectively. By Motif-X analysis, eight Ser motifs and one Thr motif were found, and five acidic, two basophilic-, and two proline-directed motifs were assigned. The potential functions of phosphoproteins in MLM were assigned by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. In GO annotation, phosphorylated microsomal proteins were involved in mRNA processing, mRNA metabolic processes, and RNA splicing. In the KEGG pathway analysis, phosphorylated microsomal proteins were highly enriched in ribosome protein processing in ER and ribosomes and in RNA transport. Furthermore, we determined that 52 and 23 phosphoproteins were potential substrates of cAMP-dependent protein kinase A and casein kinase II, respectively, many of which are 40S/60S ribosomal proteins. Overall, our results provide an overview of features of protein phosphorylation in MLMs that should be a valuable resource for the future understanding of protein synthesis or translation involving phosphorylation.

High expression of DDR1 is associated with the poor prognosis in Chinese patients with pancreatic ductal adenocarcinoma

BACKGROUND

Discoidin domain receptors 1 (DDR1), a subtype of DDRs, has been reported as a critical modulator of cellular morphogenesis, differentiation, migration and invasion.

METHODS AND RESULTS

In this study, we investigated the expression of DDR1 and its clinical association in Chinese patients with pancreatic ductal adenocarcinoma (PDAC). Across a cohort of 30 patients, we examined DDR1 expression in paired PDAC and corresponding adjacent non-tumor tissues by real-time quantitative PCR (RT-qPCR), or western blotting. DDR1 expression is significantly higher in PDAC, as compared to normal adjacent tissue, confirming results from the Oncomine databases. We validated DDR1 expression by immunohistochemistry across a non-overlapping cohort of 205 PDAC specimens. Kaplan-Meier survival curves indicate that increased expression of DDR1 is associated with a poor prognosis in PDAC patients (P = 0.013). Multivariate Cox regression analysis identified DDR1 expression, age, N classification and liver metastasis as independent prognostic factors in PDAC.

CONCLUSIONS

This study demonstrated that DDR1 can well serve as a novel prognostic biomarker in PDAC.

Endoplasmic reticulum ribosome-binding protein 1, RRBP1, promotes progression of colorectal cancer and predicts an unfavourable prognosis

BACKGROUND

Ribosome-binding protein 1 (RRBP1) has been implicated in the regulation of unfolded protein response, which is involved in almost every aspect of cancer development. We aimed to explore the significance of RRBP1 in the progression and prognosis of colorectal cancer (CRC).

METHODS

The study population consisted of 856 patients with stage I-III CRC from two hospitals. RRBP1 expression was examined by immunohistochemistry (IHC) in colorectal tissues. The correlation of RRBP1 expression and CRC occurrence was assessed in paired cancer-adjacent tissues. Factors contributing to prognosis were evaluated in a training-validation design with univariate and multivariate Cox analysis. Colorectal cancer aggressiveness caused by RRBP1 knockdown or overexpression was evaluated in CRC cells.

RESULTS

RRBP1 was aberrantly overexpressed in CRC. Compared with low-RRBP1 patients, high-RRBP1 patients had shorter disease-specific survival in the training (hazard ratio (HR), 2.423; 95% confidence interval (CI), 1.531-3.835) and validation cohorts (HR, 3.749; 95% CI, 2.166-6.448) in multivariate Cox analysis. High-RRBP1 independently predicted a shorter disease-free survival (HR, 4.821; 95% CI, 3.220-7.218) in the validation cohort. RRBP1 knockdown reduced the aggressiveness of CRC cells in vitro and inhibited the growth of CRC xenografts in vivo.

CONCLUSIONS

High RRBP1 expression facilitates CRC progression and predicts an unfavourable post-operative prognosis.