Khumalo Thandokuhle, Ferreira Eloise, Jovanovic Katarina, Veale Rob B, Weiss Stefan F T
School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, The Republic of South Africa (RSA).
PLoS One. 2015 Oct 1;10(10):e0139584. doi: 10.1371/journal.pone.0139584. eCollection 2015.
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.
由于高发病率和死亡率，癌症成为一项全球性负担，在南非的非传染性疾病中，它是第二大最常被诊断出的疾病。37kDa/67kDa层粘连蛋白受体（LRP/LR）的高表达水平是癌细胞的一个特征。该受体通过支持肿瘤血管生成、转移，尤其是在本研究中涉及的逃避凋亡，参与癌细胞的发病机制。在当前研究中，研究了LRP/LR对乳腺癌MCF-7、MDA-MB 231和WHCO1食管癌细胞细胞活力的作用。蛋白质印迹分析显示，使用siRNA-LAMR1靶向LRP mRNA可显著下调MCF-7、MDA-MB 231和WHCO1的总LRP表达水平。通过MTT试验测定，LRP/LR的这种敲低导致乳腺癌和食管癌细胞的活力显著降低。与siRNA-LAMR1相比，用针对LRP mRNA不同区域的esiRNA-RPSA转染MDA-MB 231细胞对LRP/LR表达和细胞活力具有相似的影响，排除了siRNA-LAMR1的脱靶效应。细胞活力的这种降低是凋亡诱导的结果，这分别通过膜联蛋白-V/FITC试验检测到乳腺癌MCF-7、MDA-MB 231和食管WHCO1癌细胞表面磷脂酰丝氨酸蛋白的暴露以及用Hoechst染色后观察到的核形态变化得以表明。这些观察结果表明，LRP/LR对于维持乳腺癌和食管癌细胞的细胞活力至关重要，并推荐将靶向LRP表达的siRNA技术作为乳腺癌和食管癌治疗的一种可能的新型替代技术。
