Expression of ribosomal proteins in normal and cancerous human prostate tissue

PLoS One. 2017 Oct 10;12(10):e0186047. doi: 10.1371/journal.pone.0186047. eCollection 2017.

Abstract

Few quantifiable tissue biomarkers for the diagnosis and prognosis of prostate cancer exist. Using an unbiased, quantitative approach, this study evaluates the potential of three proteins of the 40S ribosomal protein complex as putative biomarkers of malignancy in prostate cancer. Prostate tissue arrays, constructed from 82 patient samples (245 tissue cores, stage pT3a or pT3b), were stained for antibodies against three ribosomal proteins, RPS19, RPS21 and RPS24. Semi-automated Ox-DAB signal quantification using ImageJ software revealed a significant change in expression of RPS19, RPS21 and RPS24 in malignant vs non-malignant tissue (p<0.0001). Receiver operating characteristics curves were calculated to evaluate the potential of each protein as a biomarker of malignancy in prostate cancer. Positive likelihood ratios for RPS19, RPS21 and RPS24 were calculated as 2.99, 4.21, and 2.56 respectively, indicating that the overexpression of the protein is correlated with the presence of disease. Triple-labelled, quantitative, immunofluorescence (with RPS19, RPS21 and RPS24) showed significant changes (p<0.01) in the global intersection coefficient, a measure of how often two fluorophore signals intersect, for RPS19 and RPS24 only. No change was observed in the co-localization of any other permutations of the three proteins. Our results show that RPS19, RPS21 or RPS24 are upregulated in malignant tissue and may serve as putative biomarkers for prostate cancer.

MeSH terms

  • Aged
  • Biomarkers, Tumor / genetics*
  • Biomarkers, Tumor / metabolism
  • Fluorescent Antibody Technique
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Image Interpretation, Computer-Assisted
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Prostate / metabolism
  • Prostate / pathology
  • Prostatic Neoplasms / diagnosis*
  • Prostatic Neoplasms / genetics
  • Prostatic Neoplasms / metabolism
  • Prostatic Neoplasms / pathology
  • ROC Curve
  • Retrospective Studies
  • Ribosomal Proteins / genetics*
  • Ribosomal Proteins / metabolism
  • Ribosomes / genetics
  • Ribosomes / metabolism
  • Ribosomes / pathology
  • Tissue Array Analysis

Substances

  • Biomarkers, Tumor
  • RPS24 protein, human
  • Ribosomal Proteins
  • ribosomal protein S19
  • ribosomal protein S21

Grants and funding

This research was funded by the Prostate Cancer Research Centre charity (registered UK charity no. 1156027), Grant Number AA1. Open access for this article was funded by King's College London. Aquila Biomedical provided support in the form of salaries for author (MB), but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the 'author contributions' section.