Department of Biology, College of Science, Sultan Qaboos University, P. O. Box 36, Muscat, Oman.
Department of Genetics, College of Medicine, Sultan Qaboos University, P. O. Box 35, Muscat, Oman.
BMC Cancer. 2018 May 5;18(1):533. doi: 10.1186/s12885-018-4446-y.
Neuropilin-1 (NRP-1), a non-tyrosine kinase glycoprotein receptor, is associated with poor prognosis breast cancer, however transcriptomic changes triggered by NRP-1 overexpression and its association with chemoresistance in breast cancer have not yet been explored.
BT-474 NRP-1 variant cells were generated by stable overexpression of NRP-1 in the BT-474 breast cancer cell line. RNA sequencing and qRT-PCR were conducted to identify differentially expressed genes. The role of an upregulated oncogene, Tenascin C (TNC) and its associated pathway was investigated by siRNA-mediated knockdown. Resistant variants of the control and BT-474 NRP-1 cells were generated by sequential treatment with four cycles of Adriamycin/Cyclophosphamide (4xAC) followed by four cycles of Paclitaxel (4xAC + 4xPAC).
NRP-1 overexpression increased cellular tumorigenic behavior. RNA sequencing identified upregulation of an oncogene, Tenascin-C (TNC) and downregulation of several tumor suppressors in BT-474 NRP-1 cells. Additionally, protein analysis indicated activation of the TNC-associated integrin β3 (ITGB3) pathway via focal adhesion kinase (FAK), Akt (Ser473) and nuclear factor kappa B (NF-kB) p65. siRNA-mediated TNC knockdown ablated the migratory capacity of BT-474 NRP-1 cells and inactivated FAK/Akt473 signaling. NRP-1 overexpressing cells downregulated breast cancer resistance protein (BCRP/ABCG2). Consequently, sequential treatment with Adriamycin/Cyclophosphamide (AC) cytotoxic drugs to generate resistant cells indicated that BT-474 NRP-1 cells increased sensitivity to treatment by inactivating NRP-1/ITGB3/FAK/Akt/NF-kB p65 signaling compared to wild-type BT-474 resistant cells.
We thus report a novel mechanism correlating high baseline NRP-1 with upregulated TNC/ITGB3 signaling, but decreased ABCG2 expression, which sensitizes BT-474 NRP-1 cells to Adriamycin/Cyclophosphamide. The study emphasizes on the targetability of the NRP-1/ITGB3 axis and its potential as a predictive biomarker for chemotherapy response.
神经纤毛蛋白-1（NRP-1）是一种非酪氨酸激酶糖蛋白受体，与预后不良的乳腺癌相关，但 NRP-1 过表达引发的转录组变化及其与乳腺癌化疗耐药性的关系尚未得到探索。
通过在 BT-474 乳腺癌细胞系中稳定过表达 NRP-1 生成 BT-474 NRP-1 变异细胞。进行 RNA 测序和 qRT-PCR 以鉴定差异表达基因。通过 siRNA 介导的敲低研究上调的癌基因，腱生蛋白 C（TNC）及其相关途径的作用。通过用阿霉素/环磷酰胺（4xAC）进行 4 个周期的序贯处理，然后用紫杉醇（4xAC+4xPAC）进行 4 个周期，生成对照和 BT-474 NRP-1 细胞的耐药变体。
NRP-1 过表达增加了细胞的致瘤行为。RNA 测序鉴定出 BT-474 NRP-1 细胞中一种癌基因，腱生蛋白 C（TNC）的上调和几个肿瘤抑制因子的下调。此外，蛋白质分析表明，通过粘着斑激酶（FAK）、Akt（Ser473）和核因子 kappa B（NF-kB）p65，TNC 相关整合素 β3（ITGB3）途径被激活。siRNA 介导的 TNC 敲低使 BT-474 NRP-1 细胞的迁移能力减弱，并使 FAK/Akt473 信号失活。NRP-1 过表达的细胞下调乳腺癌耐药蛋白（BCRP/ABCG2）。因此，用阿霉素/环磷酰胺（AC）细胞毒性药物进行序贯处理以生成耐药细胞表明，与野生型 BT-474 耐药细胞相比，BT-474 NRP-1 细胞通过失活 NRP-1/ITGB3/FAK/Akt/NF-kB p65 信号来增加对治疗的敏感性。
因此，我们报告了一种新的机制，该机制将高基线 NRP-1 与上调的 TNC/ITGB3 信号相关联，但下调 ABCG2 表达，使 BT-474 NRP-1 细胞对阿霉素/环磷酰胺敏感。该研究强调了 NRP-1/ITGB3 轴的靶向性及其作为化疗反应预测生物标志物的潜力。
