Knockdown of LRP/LR Induces Apoptosis in Breast and Oesophageal Cancer Cells

PLoS One. 2015 Oct 1;10(10):e0139584. doi: 10.1371/journal.pone.0139584. eCollection 2015.

Abstract

Cancer is a global burden due to high incidence and mortality rates and is ranked the second most diagnosed disease amongst non-communicable diseases in South Africa. A high expression level of the 37kDa/67kDa laminin receptor (LRP/LR) is one characteristic of cancer cells. This receptor is implicated in the pathogenesis of cancer cells by supporting tumor angiogenesis, metastasis and especially for this study, the evasion of apoptosis. In the current study, the role of LRP/LR on cellular viability of breast MCF-7, MDA-MB 231 and WHCO1 oesophageal cancer cells was investigated. Western blot analysis revealed that total LRP expression levels of MCF-7, MDA-MB 231 and WHCO1 were significantly downregulated by targeting LRP mRNA using siRNA-LAMR1. This knockdown of LRP/LR resulted in a significant decrease of viability in the breast and oesophageal cancer cells as determined by an MTT assay. Transfection of MDA-MB 231 cells with esiRNA-RPSA directed against a different region of the LRP mRNA had similar effects on LRP/LR expression and cell viability compared to siRNA-LAMR1, excluding an off-target effect of siRNA-LAMR1. This reduction in cellular viability is as a consequence of apoptosis induction as indicated by the exposure of the phosphatidylserine protein on the surface of breast MCF-7, MDA-MB 231 and oesophageal WHCO1 cancer cells, respectively, detected by an Annexin-V/FITC assay as well as nuclear morphological changes observed post-staining with Hoechst. These observations indicate that LRP/LR is crucial for the maintenance of cellular viability of breast and oesophageal cancer cells and recommend siRNA technology targeting LRP expression as a possible novel alternative technique for breast and oesophageal cancer treatment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis*
  • Base Sequence
  • Blotting, Western
  • Breast Neoplasms / genetics
  • Breast Neoplasms / metabolism
  • Breast Neoplasms / pathology*
  • Cell Proliferation
  • Esophageal Neoplasms / genetics
  • Esophageal Neoplasms / metabolism
  • Esophageal Neoplasms / pathology*
  • Female
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Microscopy, Fluorescence
  • Molecular Sequence Data
  • RNA, Small Interfering / genetics*
  • Receptors, Laminin / antagonists & inhibitors
  • Receptors, Laminin / genetics
  • Receptors, Laminin / metabolism
  • Ribosomal Proteins
  • Tumor Cells, Cultured

Substances

  • RNA, Small Interfering
  • RPSA protein, human
  • Receptors, Laminin
  • Ribosomal Proteins

Grants and funding

This work was supported by the National Research Foundation, the Republic of South Africa, the Republic of South Africa. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s), and therefore, the National Research Foundation does not accept any liability in this regard thereto. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.