Anti-PI15 (aa 128-141) polyclonal antibody

Background: We aimed to screen a specific secretory protein that could serve as blood diagnostic marker for cholangiocarcinoma (CCA). Methods: Starting with the analysis of gene expression profiles in tumor tissues and matched normal tissues from cases with CCA and hepatocellular carcinoma (HCC), we identified peptidase inhibitor 15 (PI15) was a potential diagnostic marker for CCA. We demonstrated PI15 expression levels in CCA, HCC, and normal liver tissues. Furthermore, quantitative enzyme-linked immunosorbent assay (ELISA) assessed plasma PI15 levels in CCA (n = 61), HCC (n = 72), benign liver disease (n = 28), chronic hepatitis B (CHB) patients (n = 45), and healthy individuals (n = 45). The diagnostic value of PI15 was estimated by the area under the receiver operating characteristic (ROC) curve (AUC). Findings: The positive rate of PI15 expression was 70% in CCA and only 9.1% in HCC; PI15 was not detected in normal liver tissue. High levels of plasma PI15 were evident in CCA patients, whereas only low levels were observed in cases involving HCC, benign liver disease, CHB patients, and healthy individuals. Plasma PI15 levels in CCA patients were obviously reduced (p = .0014) after surgery. The AUC of plasma PI15 for discriminating between CCA and HCC was 0.735. Furthermore, with a specificity of 94.44%, the combination of CA19-9 (<98.5 U/ml) and PI15 (>13 ng/ml) yielded a sensitivity of 80.39% for CCA and HCC. Interpretation: PI15 exhibits promise as a novel marker for predicting the diagnosis and follow-up of CCA patients. (C) 2018 Published by Elsevier B.V.

Molecular identification of protein molecules surrounding nanoparticles (NPs) may provide useful information that influences NP clearance, biodistribution, and toxicity. Hence, nanoproteomics provides specific information about the environment that NPs interact with and can therefore report on the changes in protein distribution that occurs during tumorigenesis. Therefore, we hypothesized that characterization and identification of protein molecules that interact with 20 nm AuNPs from cancer and noncancer cells may provide mechanistic insights into the biology of tumor growth and metastasis and identify new therapeutic targets in ovarian cancer. Hence, in the present study, we systematically examined the interaction of the protein molecules with 20 nm AuNPs from cancer and noncancerous cell lysates. Time-resolved proteomic profiles of NP-protein complexes demonstrated electrostatic interaction to be the governing factor in the initial time-points which are dominated by further stabilization interaction at longer time-points as determined by ultraviolet visible spectroscopy (UV-vis), dynamic light scattering (DLS), measurements, transmission electron microscopy (TEM), and tandem mass spectrometry (MS/MS). Reduction in size, charge, and number of bound proteins were observed as the protein-NP complex stabilized over time. Interestingly, proteins related to mRNA processing were overwhelmingly represented on the NP-protein complex at all times. More importantly, comparative proteomic analyses revealed enrichment of a number of cancer-specific proteins on the AuNP surface. Network analyses of these proteins highlighted important hub nodes that could potentially be targeted for maximal therapeutic advantage in the treatment of ovarian cancer. The importance of this methodology and the biological significance of the network proteins were validated by a functional study of three hubs that exhibited variable connectivity, namely, PPA1, SMNDC1, and PI15. Western blot analysis revealed overexpression of these proteins in ovarian cancer cells when compared to normal cells. Silencing of PPA1, SMNDC1, and PI15 by the siRNA approach significantly inhibited proliferation of ovarian cancer cells and the effect correlated with the connectivity pattern obtained from our network analyses.