Low expression of PinX1 is associated with malignant behavior in basal-like breast cancer.
Low expression of PinX1 is associated with malignant behavior in basal-like breast cancer.
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PinX1 的低表达与基底样乳腺癌的恶性行为相关
DOI：
10.3892/or.2017.5696
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发表时间：
2017-07
期刊：
影响因子：
4.2
通讯作者：
Shi R
中科院分区：
文献类型：
--
作者：
Feng YZ;Zhang QY;Fu MT;Zhang ZF;Wei M;Zhou JY;Shi R
人类Pinx1蛋白与Shelterin蛋白相关，被广泛发现为单倍体缺陷的肿瘤抑制因子。越来越多的证据表明，在不同的癌症中，PinX1的调控被解除。然而，PinX1在基底样癌中的缺失状态及其诊断、预后和临床病理意义仍不清楚。本研究采用定量逆转录聚合酶链式反应和免疫印迹法检测了乳腺癌组织中PinX1的表达水平。免疫组织化学(IHC)法检测PinX1在组织芯片上的表达。通过受试者工作特征(ROC)曲线分析确定PinX1阳性的最佳阈值。为了阐明PinX1在BLBC中的可能作用，利用CRISPR-Cas9系统和基因转染技术构建了稳定过表达的PinX1基因敲除细胞系。采用CCK-8比色法、创伤愈合实验、Transwell实验、流式细胞仪分析和caspase-3裂解蛋白免疫印迹等方法，观察PinX1表达与细胞增殖、迁移和凋亡的关系。结果表明，在乳腺癌组织中，PinX1mRNA和蛋白的表达均下调(P<；0.05)。在免疫组化分析中，PinX1阳性表达的最佳截断值为62.5%(AUC值为0.749，P<0.01)。PinX1在管腔亚型中阳性率为76.9%(10/14)，在Her2富集型中阳性率为50%(5/10)，在基底细胞样亚型中阳性率为27.3%(9/33)。此外，在59例浸润性导管癌中，PinX1的表达与组织学分级呈负相关(P<；0.05)，与PR状态(P<；0.05)和ER状态(P<；0.05)呈正相关。这些结果表明，PinX1的低表达与乳腺癌侵袭性的临床病理意义有关，尤其是在基底细胞样亚型。此外，我们还发现PinX1过表达抑制了BLBC的增殖率和迁移能力，增加了细胞的凋亡率。我们的研究结果表明，PinX1的低表达与基底细胞样亚型乳腺癌的恶性行为有关。PinX1可能是BLBC的一个可行的生物标志物和分子靶点。
Human Pinx1 protein, associated with shelterin proteins, is widely revealed as a haploinsufficient tumor suppressor. Growing evidence has manifested the deregulation of PinX1 in distinct cancers. Nonetheless, the loss status of PinX1 and its diagnostic, prognostic and clinicopathological significance in Basal-like breast cancer are still unclear. In the present study, the PinX1 expression levels of breast cancer tissues were investigated by qRT-PCR and immunoblotting assays. Then immunohistochemistry (IHC) was performed to detect PinX1 expression on a tissue microarray. The optimal threshold for PinX1 positivity was determined by receiver operating characteristic (ROC) curve analysis. To clarify the probable role of PinX1 in BLBC, the PinX1 knockout and stably over-expressed MDA-MB-231 cell lines were constructed by the CRISPR-Cas9 system and gene transfection. The association of PinX1 expression with cell proliferation, migration and apoptosis of MDA-MB-231 cells were observed by CCK-8 assay, wound healing assay, Transwell assay, flow cytometric analysis and immunoblotting of the cleaved caspase-3 protein level. Our results showed that both PinX1 mRNA and protein expression were downregulated in breast cancer tissues (P<0.05). In IHC analysis, the optimal cut-off parameter for PinX1 positive expression was 62.5% (the AUC was 0.749, P<0.01). PinX1 positivity was 76.9% (10/14) in luminal subtypes, 50% (5/10) in Her2-enriched breast cancer and 27.3% (9/33) in basal-like subtypes. Besides, in 59 invasive ductal breast carcinomas, PinX1 expression was inversely related to histology grade (P<0.05) while it was positively associated with PR status (P<0.05) and ER status (P<0.05). These results indicated that low expression of PinX1 correlated with aggressive clinicopathological significance of breast cancer, especially in the basal-like subtype. Besides, we identified that overexpression of PinX1 inhibited the proliferation rates and migration ability and increased the apoptosis rates of BLBC. Our findings demonstrated that low expression of PinX1 was associated with malignant behaviors in basal-like subtype of breast cancer. PinX1 is likely a feasible biomarker and molecular target of BLBC.