Ebp1 protein expression in cervical cancer tissue and its significance

Identification of diagnostic biomarkers via weighted correlation network analysis in colorectal cancer using a system biology approach

Colorectal cancer (CRC) is the third most frequent cancer to be diagnosed in both females and males necessitating identification of effective biomarkers. An in-silico system biology approach called weighted gene co-expression network analysis (WGCNA) can be used to examine gene expression in a complicated network of regulatory genes. In the current study, the co-expression network of DEGs connected to CRC and their target genes was built using the WGCNA algorithm. GO and KEGG pathway analysis were carried out to learn more about the biological role of the DEmRNAs. These findings revealed that the genes were mostly enriched in the biological processes that were involved in the regulation of hormone levels, extracellular matrix organization, and extracellular structure organization. The intersection of genes between hub genes and DEmRNAs showed that DKC1, PA2G4, LYAR and NOLC1 were the clinically final hub genes of CRC.

PA2G4 promotes the metastasis of hepatocellular carcinoma by stabilizing FYN mRNA in a YTHDF2-dependent manner

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide with high mortality. Advanced stage upon diagnosis and cancer metastasis are the main reasons for the dismal prognosis of HCC in large part. The role of proliferation associated protein 2G4 (PA2G4) in tumorigenesis and cancer progression has been widely investigated in various cancers. However, whether and how PA2G4 participates in HCC metastasis is still underexplored.

RESULTS

We found that the mRNA and protein levels of PA2G4 were higher in HCC samples than in normal liver tissues, and high expression of PA2G4 in HCC was correlated with a poor prognosis, by an integrative analysis of immunohistochemistry (IHC), western blot and bioinformatic approach. Moreover, the expression of PA2G4 was elevated in HCC patients with metastases than those metastasis-free. Cell migration, invasion, phalloidin staining and western blot analyses demonstrated that PA2G4 promoted epithelial to mesenchymal transition (EMT) of HCC cells in vitro. And a lung metastasis animal model exhibited that PA2G4 enhanced metastatic ability of HCC cells in vivo. RNA-sequencing combined with dual luciferase reporter assay and evaluation of mRNA half-time indicated that PA2G4 increased FYN expression by stabilizing its mRNA transcript. Recovering the impaired FYN level induced by PA2G4 knockdown rescued the impeded cell mobilities. Furthermore, endogenous immunoprecipitation (IP) and in-situ immunofluorescence (IF) showed that YTH N6-methyladenosine RNA binding protein 2 (YTHDF2) was the endogenous binding patterner of PA2G4. In addition, RNA binding protein immunoprecipitation (RIP) and anti- N6-methyladenosine immunoprecipitation (MeRIP) assays demonstrated that FYN mRNA was N6-methyladenosine (m6A) modified and bound with PA2G4, as well as YTHDF2. Moreover, the m6A catalytic ability of YTHDF2 was found indispensable for the regulation of FYN by PA2G4. At last, the correlation of expression levels between PA2G4 and FYN in HCC tissues was verified by IHC and western blot analysis.

CONCLUSIONS

These results indicate that PA2G4 plays a pro-metastatic role by increasing FYN expression through binding with YTHDF2 in HCC. PA2G4 may become a reliable prognostic marker or therapeutic target for HCC patients.

Increased PA2G4 Expression Is an Unfavorable Factor in Nasopharyngeal Carcinoma

PA2G4 plays a dual role in tumors. However, the correlation of its expression with clinical feature and prognosis has never been reported in nasopharyngeal carcinoma (NPC). Using immunohistochemical staining, we examined PA2G4 protein level in clinicopathologically characterized 201 NPC cases (138 male and 63 female) with age ranging from 21 to 83 years and 45 nasopharyngeal (NP) tissues. Statistical methods were used to assess the difference in PA2G4 expression and its relationship with clinical parameters and prognosis in NPC. Immunohistochemical analysis showed that the protein expression of PA2G4 examined in NPC tissues was higher than that in the nasopharyngeal tissues (P=0.005). In addition, high levels of PA2G4 protein were positively correlated with tumor size (T classification) (P<0.001), the status of lymph node metastasis (N classification) (P<0.001), distant metastasis (P=0.029), and clinical stage (P<0.001) of NPC patients. Patients with higher PA2G4 expression had a significantly shorter overall survival time than did patients with low PA2G4 expression. Stratified analysis indicated that high expression of PA2G4 showed the inversed survival time in clinical stages III-IV, but not stages I-II. Finally, multivariate analysis suggested that the level of PA2G4 expression was an independent prognostic indicator (P<0.001) for the survival of patients with NPC. Elevated protein expression of PA2G4 was significantly shown, which plays an unfavorable outcome for NPC patient survival.

Understanding Cervical Cancer through Proteomics

Cancer is one of the leading public health issues worldwide, and the number of cancer patients increases every day. Particularly, cervical cancer (CC) is still the second leading cause of cancer death in women from developing countries. Thus, it is essential to deepen our knowledge about the molecular pathogenesis of CC and propose new therapeutic targets and new methods to diagnose this disease in its early stages. Differential expression analysis using high-throughput techniques applied to biological samples allows determining the physiological state of normal cells and the changes produced by cancer development. The cluster of differential molecular profiles in the genome, the transcriptome, or the proteome is analyzed in the disease, and it is called the molecular signature of cancer. Proteomic analysis of biological samples of patients with different grades of cervical intraepithelial neoplasia (CIN) and CC has served to elucidate the pathways involved in the development and progression of cancer and identify cervical proteins associated with CC. However, several cervical carcinogenesis mechanisms are still unclear. Detecting pathologies in their earliest stages can significantly improve a patient's survival rate, prognosis, and recurrence. The present review is an update on the proteomic study of CC.

ErbB3-binding protein 1 (EBP1) represses HNF4α-mediated transcription and insulin secretion in pancreatic β-cells

HNF4α (hepatocyte nuclear factor 4α) is one of the master regulators of pancreatic β-cell development and function, and mutations in the HNF4α gene are well-known monogenic causes of diabetes. As a member of the nuclear receptor family, HNF4α exerts its gene regulatory function through various molecular interactions; however, there is a paucity of knowledge of the different functional complexes in which HNF4α participates. Here, to find HNF4α-binding proteins in pancreatic β-cells, we used yeast two-hybrid screening, a mammalian two-hybrid assay, and glutathione S-transferase pulldown approaches, which identified EBP1 (ErbB3-binding protein 1) as a factor that binds HNF4α in a LXXLL motif-mediated manner. In the β-cells, EBP1 suppressed the expression of HNF4α target genes that are implicated in insulin secretion, which is impaired in HNF4α mutation-driven diabetes. The crystal structure of the HNF4α ligand-binding domain in complex with a peptide harboring the EBP1 LXXLL motif at 3.15Å resolution hinted at the molecular basis of the repression. The details of the structure suggested that EBP1's LXXLL motif competes with HNF4α coactivators for the same binding pocket and thereby prevents recruitment of additional transcriptional coactivators. These findings provide further evidence that EBP1 plays multiple cellular roles and is involved in nuclear receptor-mediated gene regulation. Selective disruption of the HNF4α-EBP1 interaction or tissue-specific EBP1 inactivation can enhance HNF4α activities and thereby improve insulin secretion in β-cells, potentially representing a new strategy for managing diabetes and related metabolic disorders.

Distinct Interactions of EBP1 Isoforms with FBXW7 Elicits Different Functions in Cancer

The ErbB3 receptor-binding protein EBP1 encodes two alternatively spliced isoforms P48 and P42. While there is evidence of differential roles for these isoforms in tumorigenesis, little is known about their underlying mechanisms. Here, we demonstrate that EBP1 isoforms interact with the SCF-type ubiquitin ligase FBXW7 in distinct ways to exert opposing roles in tumorigenesis. EBP1 P48 bound to the WD domain of FBXW7 as an oncogenic substrate of FBXW7. EBP1 P48 binding sequestered FBXW7α to the cytosol, modulating its role in protein degradation and attenuating its tumor suppressor function. In contrast, EBP1 P42 bound to both the F-box domain of FBXW7 as well as FBXW7 substrates. This adapter function of EBP1 P42 stabilized the interaction of FBXW7 with its substrates and promoted FBXW7-mediated degradation of oncogenic targets, enhancing its overall tumor-suppressing function. Overall, our results establish distinct physical and functional interactions between FBXW7 and EBP1 isoforms, which yield their mechanistically unique isoform-specific functions of EBP1 in cancer. Cancer Res; 77(8); 1983-96. ©2017 AACR.