Sendon-Lago Juan, Seoane Samuel, Eiro Noemi, Bermudez Maria A, Macia Manuel, Garcia-Caballero Tomas, Vizoso Francisco J, Perez-Fernandez Roman
Department of Physiology- Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), School of Medicine, University of Santiago de Compostela, Praza do Obradoiro, Santiago de Compostela, 15782, Spain.
Unidad de Investigación, Fundacion Hospital de Jove, Avenida Eduardo Castro, Gijón, 33290, Spain.
Breast Cancer Res. 2014 Dec 20;16(6):505. doi: 10.1186/s13058-014-0505-8.
The POU class 1 homeobox 1 transcription factor (POU1F1, also known as Pit-1) is expressed in the mammary gland and its overexpression induces profound phenotypic changes in proteins involved in cell proliferation, apoptosis, and invasion. Patients with breast cancer and elevated expression of Pit-1 show a positive correlation with the occurrence of distant metastasis. In this study we evaluate the relationship between Pit-1 and two collagenases: matrix metalloproteinase-1 (MMP-1) and matrix metalloproteinase-13 (MMP-13), which have been related to metastasis in breast cancer.
We began by transfecting the MCF-7 and MDA-MB-231 human breast adenocarcinoma cell lines with the Pit-1 overexpression vector (pRSV-hPit-1). Afterward, the mRNA, protein, and transcriptional regulation of both MMP-1 and MMP-13 were evaluated by real-time PCR, Western blot, chromatin immunoprecipitation (ChIP), and luciferase reporter assays. We also evaluated Pit-1 overexpression with MMP-1 and MMP-13 knockdown in a severe combined immunodeficiency (SCID) mouse tumor xenograft model. Finally, by immunohistochemistry we correlated Pit-1 with MMP-1 and MMP-13 protein expression in 110 human breast tumors samples.
Our data show that Pit-1 increases mRNA and protein of both MMP-1 and MMP-13 through direct transcriptional regulation. In SCID mice, knockdown of MMP-13 completely blocked lung metastasis in Pit-1-overexpressing MCF-7 cells injected into the mammary fat pad. In breast cancer patients, expression of Pit-1 was found to be positively correlated with the presence of both MMP-1 and MMP-13.
Our data indicates that Pit-1 regulates MMP-1 and MMP-13, and that inhibition of MMP-13 blocked invasiveness to lung in Pit-1-overexpressed breast cancer cells.
POU1F1（也称为Pit-1）是一种POU家族1类同源异型盒转录因子，在乳腺中表达，其过表达会诱导参与细胞增殖、凋亡和侵袭的蛋白质发生深刻的表型变化。乳腺癌患者中Pit-1表达升高与远处转移的发生呈正相关。在本研究中，我们评估了Pit-1与两种胶原酶（基质金属蛋白酶-1（MMP-1）和基质金属蛋白酶-13（MMP-13））之间的关系，这两种酶与乳腺癌转移有关。
我们首先用Pit-1过表达载体（pRSV-hPit-1）转染MCF-7和MDA-MB-231人乳腺腺癌细胞系。随后，通过实时PCR、蛋白质印迹、染色质免疫沉淀（ChIP）和荧光素酶报告基因检测评估MMP-1和MMP-13的mRNA、蛋白质和转录调控。我们还在严重联合免疫缺陷（SCID）小鼠肿瘤异种移植模型中评估了Pit-1过表达与MMP-1和MMP-13敲低的情况。最后，通过免疫组织化学，我们将110例人乳腺肿瘤样本中的Pit-1与MMP-1和MMP-13蛋白表达进行了关联分析。
我们的数据表明，Pit-1通过直接转录调控增加MMP-1和MMP-13的mRNA和蛋白质水平。在SCID小鼠中，敲低MMP-13完全阻断了注射到乳腺脂肪垫中的Pit-1过表达MCF-7细胞的肺转移。在乳腺癌患者中，发现Pit-1的表达与MMP-1和MMP-13的存在呈正相关。
我们的数据表明，Pit-1调节MMP-1和MMP-13，并且抑制MMP-13可阻断Pit-1过表达的乳腺癌细胞向肺的侵袭。
