Tsai Yi-Fang, Tseng Ling-Ming, Hsu Chih-Yi, Yang Muh-Hwa, Chiu Jen-Hwey, Shyr Yi-Ming
Comprehensive Breast Health Center & Division of General Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan, Republic of China.
Institute of Clinical Medicine, Institute of Traditional Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China.
PLoS One. 2017 Jun 12;12(6):e0178173. doi: 10.1371/journal.pone.0178173. eCollection 2017.
There is good evidence that the tumor microenvironment plays an important role in cancer metastasis and progression. Our previous studies have shown that brain-derived neurotrophic factor (BDNF) participates in the process of metastasis and in the migration of cancer cells. The aim of this study was to investigate the role of BDNF on the tumor cell microenvironment, namely, the cancer cell-endothelial cell interaction of TNBC cells.
We conducted oligoneucleotide microarray analysis of potential biomarkers that are able to differentiate recurrent TNBC from non-recurrent TNBC. The MDA-MB-231 and human endothelial HUVEC lines were used for this study and our approaches included functional studies, such as migration assay, as well as Western blot and real-time PCR analysis of migration and angiogenic signaling. In addition, we analyzed the survival outcome of TNBC breast cancer patients according to their expression level of BDNF using clinical samples.
The results demonstrated that BDNF was able to bring about autocrinal (MDA-MB-231) and paracrinal (HUVECs) regulation of BDNF-TrkB gene expression and this affected cell migratory activity. The BDNF-induced migratory activity was blocked by inhibitors of ERK, PI3K and TrkB when MDA-MB-231 cells were examined, but only an inhibitor of ERK blocked this activity when HUVEC cells were used. Furthermore, decreased migratory activity was found for △BDNF and △TrkB cell lines. Ingenuity pathway analysis (IPA) of MDA-MB-231 cells showed that BDNF is a key factor that is able to regulate a network made up of metalloproteases and calmodulin. Protein expression levels in a tissue array of tumor slices were found to be correlated with patient prognosis and the results showed that there was significant correlation of TrkB expression, but not of BDNF. expressionwith patient DFS and OS.
Our study demonstrates that up-regulation of the BDNF signaling pathway seems tobe involved in the mechanism associated with early recurrence in triple negative breast cancer cell. In addition, BDNF can function in either an autocrine or a paracrine manner to increase the migration ability of both MDA-MB-231 cells and HUVEC cells. Finally, overexpression of TrkB, but not of BDNF, is significantly associated with a poor survival outcome for TNBC patients.
有充分证据表明肿瘤微环境在癌症转移和进展中起重要作用。我们之前的研究表明，脑源性神经营养因子（BDNF）参与转移过程以及癌细胞的迁移。本研究的目的是探讨BDNF在肿瘤细胞微环境中的作用，即三阴性乳腺癌（TNBC）细胞的癌细胞 - 内皮细胞相互作用。
我们对能够区分复发性TNBC和非复发性TNBC的潜在生物标志物进行了寡核苷酸微阵列分析。本研究使用了MDA-MB-231和人内皮HUVEC细胞系，我们的方法包括功能研究，如迁移试验，以及对迁移和血管生成信号的蛋白质印迹和实时PCR分析。此外，我们使用临床样本根据BDNF的表达水平分析了TNBC乳腺癌患者的生存结果。
结果表明，BDNF能够引起BDNF-TrkB基因表达的自分泌（MDA-MB-231）和旁分泌（HUVECs）调节，这影响了细胞迁移活性。在检测MDA-MB-231细胞时，BDNF诱导的迁移活性被ERK、PI3K和TrkB的抑制剂阻断，但在使用HUVEC细胞时，只有ERK抑制剂阻断了这种活性。此外，发现△BDNF和△TrkB细胞系的迁移活性降低。对MDA-MB-231细胞的 Ingenuity 通路分析（IPA）表明，BDNF是能够调节由金属蛋白酶和钙调蛋白组成的网络的关键因子。在肿瘤切片组织阵列中的蛋白质表达水平与患者预后相关，结果表明TrkB表达与患者DFS和OS有显著相关性，而BDNF表达无显著相关性。
我们的研究表明，BDNF信号通路的上调似乎参与了三阴性乳腺癌细胞早期复发相关的机制。此外，BDNF可以以自分泌或旁分泌方式发挥作用，以增加MDA-MB-231细胞和HUVEC细胞的迁移能力。最后，TrkB的过表达而非BDNF的过表达与TNBC患者的不良生存结果显著相关。
