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.