Chongdong Liu

Proteomic analysis of human serum for Finding pathogenic factors and potential biomarkers in preeclampsia

OBJECTIVE(S) To apply a novel proteomic method to discover potential pathogenic factors and biomarkers of preeclampsia. STUDY DESIGN Sera from five patients complicated with preeclampsia and five healthy pregnant controls were separately pooled. Each pool was treated with peptide ligand library beads (PLLBs) to remove high abundance proteins by affinity and thus enrich low abundance proteins. The proteins from the eluate were analyzed by a combination of 1D Gel-LC-MS/MS. Protein expression levels were quantified using spectral counts and the extracted ion current. RESULTS 1172 unique proteins in preeclampsia and 1149 in healthy controls were identified in the present study. 51 proteins were differentially expressed between preeclampsia and healthy pregnant women including chorionic somatommammptropin hormone (CSH) and fibulin-1. 31 proteins identified were up-regulated and 20 were down-regulated. CONCLUSIONS The results demonstrate that peptide ligand library combining with 1D gel-LC-MS/MS analysis is an efficient method to identify differentially expressed proteins in sera and two biological processes of complement and coagulation activations and lipid metabolism were involved in the pathogenesis of preeclampsia.

Transthyretin as a novel candidate biomarker for preeclampsia

Preeclampsia (PE) is considered to be a potentially fatal complication during pregnancy. However, no effective laboratory assessment has been developed to enable early diagnosis and monitoring of PE. The present study aimed to identify differentially expressed transthyretin (TTR) during severe PE and evaluate TTR as a possible biomarker of this disease. TTR levels were determined in the different gestational weeks of normal pregnancy (before 20 weeks, n=41; after 20 weeks, n=39) using enzyme-linked immunosorbent assay (ELISA). TTR concentrations in pregnant females with severe PE (n=43) were compared with those in healthy matched control subjects (n=37) using western blot analysis and ELISA. The median TTR concentration during severe PE in each month of gestation was significantly lower than the concentrations recorded during normal pregnancy. TTR levels in females with severe PE were significantly downregulated compared with the control subjects (P<0.001; area under the curve, 0.834–0.967). Thus, TTR may be used as a potential biomarker of PE.

Proteomics Analysis for Finding Serum Markers of Ovarian Cancer

A combination of peptide ligand library beads (PLLB) and 1D gel liquid chromatography-mass spectrometry/mass spectrometry (1DGel-LC-MS/MS) was employed to analyze serum samples from patients with ovarian cancer and from healthy controls. Proteomic analysis identified 1200 serum proteins, among which 57 proteins were upregulated and 10 were downregulated in the sera from cancer patients. Retinol binding protein 4 (RBP4) is highly upregulated in the ovarian cancer serum samples. ELISA was employed to measure plasma concentrations of RBP4 in 80 samples from ovarian cancer patients, healthy individuals, myoma patients, and patients with benign ovarian tumor, respectively. The plasma concentrations of RBP4 ranging from 76.91 to 120.08 ng/mL with the mean value 89.13 ± 1.67 ng/mL in ovarian cancer patients are significantly higher than those in healthy individuals (10.85 ± 2.38 ng/mL). Results were further confirmed with immunohistochemistry, demonstrating that RBP4 expression levels in normal ovarian tissue were lower than those in ovarian cancer tissues. Our results suggested that RBP4 is a potential biomarker for diagnostic of screening ovarian cancer.

Serum markers of pre‐eclampsia identified on proteomics

Pre‐eclampsia (PE) is a disorder of pregnancy associated with maternal and fetal mortality and morbidity. The aim of the present study was to use proteomics to identify biomarkers of, and elucidate the pathogenesis of, PE.

Phosphoproteomics Analysis of Endometrium in Women with or without Endometriosis.

Background:The molecular mechanisms underlying the endometriosis are still not completely understood. In order to test the hypothesis that the approaches in phosphoproteomics might contribute to the identification of key biomarkers to assess disease pathogenesis and drug targets, we carried out a phosphoproteomics analysis of human endometrium. Methods:A large-scale differential phosphoproteome analysis, using peptide enrichment of titanium dioxide purify and sequential elution from immobilized metal affinity chromatography with linear trap quadrupole-tandem mass spectrometry, was performed in endometrium tissues from 8 women with or without endometriosis. Results:The phosphorylation profiling of endometrium from endometriosis patients had been obtained, and found that identified 516 proteins were modified at phosphorylation level during endometriosis. Gene ontology annotation analysis showed that these proteins were enriched in cellular processes of binding and catalytic activity. Further pathway analysis showed that ribosome pathway and focal adhesion pathway were the top two pathways, which might be deregulated during the development of endometriosis. Conclusions:That large-scale phosphoproteome quantification has been successfully identified in endometrium tissues of women with or without endometriosis will provide new insights to understand the molecular mechanisms of the development of endometriosis.

Recurrence‑associated factors of laparoscopic adenomyomectomy for severely symptomatic adenomyoma

The present study aimed to identify which patients with adenomyoma would benefit from sparing the uterus and which patients should undergo a hysterectomy to avoid secondary surgery. Patients with pathology-proven adenomyoma admitted to Beijing Chao-Yang Hospital between November 2005 and November 2015 were retrospectively reviewed. Relief and reappearance of dysmenorrhea following laparoscopic adenomyomectomy were evaluated. All 49 patients (mean age, 40.6±5.2 years; age range, 26–51 years) presented with severe dysmenorrhea prior to surgery. Dysmenorrhea was identified to be relieved in 83.7% (41/49) of patients at the 6-month follow-up. No factors were revealed to have a significant effect on the surgical outcome. The median follow-up period was 4.6 (1–11) years; and 24.5% (12/49) of patients experienced recurrence of dysmenorrhea. Multivariate analysis identified preoperative serum cancer antigen 125 (CA 125) levels [hazard ratio (HR), 2.356; 95% confidence interval (CI), 1.271–3.570; P=0.011], postoperative gonadotropin-releasing hormone agonist (GnRH-a) treatment (HR, 0.540; 95% CI, 0.241–0.873; P=0.017) and accompanying endometriosis (HR, 2.182; 95% CI, 1.556–3.031; P=0.003) as independent risk factors for relapse. Laparoscopic adenomyomectomy is effective for alleviating dysmenorrhea in patients with adenomyoma. Patients with lower preoperative serum CA 125 levels without accompanying endometriosis benefited greater from adenomyomectomy compared with all other patients. Postoperative GnRH-a treatment strengthens therapeutic effects.

RBP4 regulates trophoblastic cell proliferation and invasion via the PI3K/AKT signaling pathway

Insufficient trophoblast invasion is associated with preeclampsia (PE) development. Retinol-binding protein 4 (RBP4) is important for regulating cell differentiation, migration and invasion. The aim of the present study was to determine RBP4 expression and function in the human placenta and to examine the underlying mechanisms. In the present study, RBP4 expression was determined in serum samples from 35 pregnant women with PE and 30 healthy pregnant women using enzyme-linked immunosorbent assays. Cell proliferation was assessed by Cell Counting Kit-8 assays, and cell invasion was examined with transwell assays. RBP4 concentrations were significantly lower in the PE group when compared with the control group. RBP4 overexpression enhanced HTR8/SVneo cell proliferation and invasion, and the levels of phosphorylated (p-) phosphoinositide 3-kinase (PI3K) and p-protein kinase B (AKT) in HTR8/SVneo cells. RBP4 knockdown significantly inhibited HTR8/SVneo cell proliferation and invasion, and repressed the expression of matrix metalloproteinases. In addition, RBP4 knockdown significantly reduced the levels of p-PI3K and p-AKT in HTR8/SVneo cells. Taken together, the results of the present study demonstrated that RBP4 overexpression increased HTR8/SVneo cell proliferation and invasion by suppressing PI3K/AKT signaling and RBP4 knockdown induced the opposite effects.

Expression and prognostic value of CLIC1 in epithelial ovarian cancer

The clinical significance of the chloride intracellular channel 1 (CLIC1) protein in ovarian cancer is yet to be determined. The present study aimed to investigate the association between CLIC1 expression, and clinicopathological features and prognosis of patients with epithelial ovarian cancer. In this retrospective study, CLIC1 level was determined by reverse transcription-quantitative polymerase chain reaction, western blotting and immunohistochemical staining. The association between CLIC1 expression and clinicopathological characteristics were evaluated. Progression-free survival and overall survival were assessed by univariate, and multivariate analyses. mRNA and protein levels of CLIC1 were significantly higher in cancerous tissues than in healthy ovarian tissues (P<0.001). CLIC1 signals in epithelial ovarian cancer tissues were significantly higher than that in healthy tissues (P<0.001). CLIC1 expression was significantly higher in higher-grade tumors than in low-grade tumors (P<0.001). Moreover, overexpression of CLIC1 was associated with cisplatin resistance (P<0.001). CLIC1 expression was an independent factor that predicted shorter progression-free survival (P=0.006) and overall survival (P=0.002) for patients with epithelial ovarian cancer. These findings indicate that CLIC1 is overexpressed and is associated with poor prognosis in patients with epithelial ovarian cancer.

Prognostic values of long noncoding RNA PVT1 in various carcinomas: An updated systematic review and meta-analysis

Cancers have been a worldwide health problem with a high mortality rate, but ideal biomarkers are not available to effectively screen and diagnose patients. Currently, an increasing number of long noncoding RNAs have been reported to be abnormally expressed in human carcinomas and play a vital role in tumourigenesis. Plasmacytoma variant translocation 1 (PVT1) is upregulated in various carcinomas, and its overexpression is associated with poor survival in cancer patients. We conduct an updated meta‐analysis to determine its potential in prognosis for tumours. In total, 14 studies comprising 2435 patients were enrolled according to Reporting Recommendations for Tumour Marker Prognostic Studies guidelines. High PVT1 expression indicated poor overall survival (hazard ratio [HR] = 1.98, 95% confidence interval [CI]: 1.62‐2.42, P < 0.00001) and disease‐free survival (HR = 1.63, 95% CI: 1.45‐1.84, P < 0.00001). Additionally, increased PVT1 expression was positively associated with lymphatic node metastasis (odd ratio [OR] = 2.87, 95% CI: 1.66‐4.96, P = 0.0002), distant metastasis (OR = 2.47, 95% CI: 1.74‐3.50, P < 0.00001), advanced tumour‐node‐metastasis stages (OR = 2.59, 95% CI: 1.38‐4.88, P = 0.003). New findings highlight that PVT1 acts as competing RNA to microRNAs to protect mRNAs from miRNAs repression. Therefore, we also discuss PVT1‐related microRNAs and their interaction in tumourigenesis. In conclusion, PVT1 may be a potential biomarker of poor prognosis for patients with different cancer types.