Department of Microbiology, Tumor and Cell biology (MTC), Karolinska Institutet, 171 77, Stockholm, Sweden.
Department of Oncology-Pathology, Karolinska Institutet, 171 76, Stockholm, Sweden.
Cell Oncol (Dordr). 2017 Dec;40(6):631-638. doi: 10.1007/s13402-017-0340-x. Epub 2017 Jul 4.
Multidrug resistance (MDR) is a major cause of treatment failure. In cancer cells, MDR is often caused by an increased efflux of therapeutic drugs mediated by an up-regulation of ATP binding cassette (ABC) transporters. It has previously been shown that oncogenic ΔNp73 plays an important role in chemo-resistance. Here we aimed at unraveling the role of ΔNp73 in regulating multidrug resistance in breast cancer and melanoma cells.
KEGG pathway analysis was used to identify pathways enriched in breast cancer samples with a high ΔNp73 expression. We found that the ABC transporter pathway was most enriched. The expression of selected ABC transporters was analyzed using qRT-PCR upon siRNA/shRNA-mediated knockdown or exogenous overexpression of ΔNp73 in the breast cancer-derived cell lines MCF7 and MDA-MB-231, as well as in primary melanoma samples and in the melanoma-derived cell line SK-MEL-28. The ability to efflux doxorubicin and the concomitant effects on cell proliferation were assessed using flow cytometry and WST-1 assays.
We found that high ΔNp73 levels correlate with a general up-regulation of ABC transporters in breast cancer samples. In addition, we found that exogenous expression of ΔNp73 led to an increase in the expression of ABCB1 and ABCB5 in the breast cancer-derived cell lines tested, while knocking down of ΔNp73 resulted in a reduction in ABCB1 and ABCB5 expression. In addition, we found that ΔNp73 reduction leads to an intracellular retention of doxorubicin in MDA-MB-231 and MCF7 cells and a concomitant decrease in cell proliferation. The effect of ΔNp73 on ABCB5 expression was further confirmed in metastases from melanoma patients and in the melanoma-derived cell line SK-MEL-28.
Our data support a role for ΔNp73 in the multidrug-resistance of breast cancer and melanoma cells.
多药耐药（MDR）是治疗失败的主要原因。在癌细胞中，MDR 通常是由 ATP 结合盒（ABC）转运蛋白的上调介导的治疗药物的外排增加引起的。先前已经表明，致癌ΔNp73 在化疗耐药中起着重要作用。在这里，我们旨在揭示ΔNp73 在调节乳腺癌和黑色素瘤细胞多药耐药中的作用。
使用 KEGG 途径分析来鉴定ΔNp73 高表达的乳腺癌样本中富集的途径。我们发现 ABC 转运体途径最丰富。使用 qRT-PCR 分析 siRNA/shRNA 介导的敲低或外源性过表达ΔNp73 后，在乳腺癌衍生细胞系 MCF7 和 MDA-MB-231 以及原发性黑色素瘤样本和黑色素瘤衍生细胞系 SK-MEL-28 中分析选定的 ABC 转运体的表达。使用流式细胞术和 WST-1 测定评估阿霉素外排的能力以及对细胞增殖的伴随影响。
我们发现高ΔNp73 水平与乳腺癌样本中 ABC 转运体的普遍上调相关。此外，我们发现外源性表达ΔNp73 导致测试的乳腺癌衍生细胞系中 ABCB1 和 ABCB5 的表达增加，而ΔNp73 的敲低导致 ABCB1 和 ABCB5 表达减少。此外，我们发现ΔNp73 减少导致 MDA-MB-231 和 MCF7 细胞内阿霉素的保留和细胞增殖的相应减少。在黑色素瘤患者的转移灶和黑色素瘤衍生细胞系 SK-MEL-28 中进一步证实了ΔNp73 对 ABCB5 表达的影响。
我们的数据支持ΔNp73 在乳腺癌和黑色素瘤细胞的多药耐药中的作用。
