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

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.

Laminin degradation by matrix metalloproteinase 9 promotes ketamine‐induced neuronal apoptosis in the early developing rat retina

“…22,31 Our study tion, invasion, angiogenesis, ECM remodeling, and apoptosis. 22,32,33 However, laminin-integrin binding has also been reported to modulate neuronal survival through the Akt or focal adhesion kinase signaling pathway. 16,34 Whether the laminin-integrin signaling pathway is involved in ketamine-induced apoptosis needs further investigation.…”

Tumour cell blebbing and extracellular vesicle shedding: key role of matrikines and ribosomal protein SA

“…The correlation between RPSA expression and tumour aggressiveness proposes RPSA as a promising strong target in fight against cancer but also in prion diseases and Alzheimer's disease. 18 Therefore, by its multiple functions like maintenance of nuclear structures and translational processes, 58 Only the pharmacological approaches (green tea polyphenol EGCG) can overcome this difficulty.…”

Knockdown of LRP/LR induces apoptosis in pancreatic cancer and neuroblastoma cells through activation of caspases

“…Besides its normal roles in mediating cell viability, cellular adhesion and functioning as a member of the ribosomal translational machinery, LRP/LR has been implicated in a number of pathological processes including cancer and metastasis [45] . However, the induction of apoptosis in response to downregulation of LRP/LR, as shown here and previously for MCF-7, MDA-MB231and WHCO1 cells [32] , suggests that this may not be a practical approach without specific targeting to avoid inducing apoptosis in non-tumourigenic cells. Interestingly, though, we have previously shown that shRNA mediated downregulation of LRP/LR had no significant effect on the viability of non-cancerous HEK293 cells suggesting that this protein might be crucial for cell survival in certain cell types only [17] .…”

“…Due to the involvement of LRP/LR in these aforementioned numerous tumourigenic processes, the role of this receptor in cell survival and viability has become an attractive topic of research [29] . Recent studies showed reductions in the viability of liver (Hep3b) [30] , lung (A549) [31] , cervical (HeLa) [31] , breast (MCF-7 and MDA-MB231) [32] and oesophageal cancer (WHCO1) [32] cells after siRNA-mediated downregulation of LRP/LRthus suggesting that LRP/LR plays a pivotal role in the maintenance of tumour cell viability. Furthermore it has been shown that LRP/LR plays an important role in apoptosis [30][31][32] .…”

“…There are two main pathways by which caspases can be activated and thereby induce apoptosis, namely the death receptor (extrinsic) pathway and the mitochondrial (intrinsic) pathway [34] . Recent studies made use of siRNA technology to downregulate LRP/LR and assess the effects of this down-regulation on apoptosis [31,32] . siRNAmediated LRP/LR down-regulation was shown to significantly reduce cellular viability of lung (A549) and cervical cancer (HeLa) cells and increase the levels of caspase-3 activity in both cell lines, thus suggesting that LRP/LR is pivotal in the maintenance of cellular viability as well as the evasion of apoptosis in tumour cells.…”