PO.TB03.02 · 肿瘤生物学
基质MTA1沉默重编程间充质干细胞以抑制三阴性乳腺癌中的EMT和远处转移
Stromal MTA1 silencing reprograms mesenchymal stem cells to suppress EMT and distant metastasis in triple-negative breast cancer
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
背景：转移相关蛋白-1（MTA1）是一种染色质调控因子，在包括三阴性乳腺癌（TNBC）在内的侵袭性癌症中驱动上皮-间质转化（EMT）、侵袭和转移能力。虽然肿瘤细胞MTA1的作用已有充分记录，但其在间充质干细胞（MSC，肿瘤微环境的关键调控因子）中的基质贡献在很大程度上仍未被探索。我们研究了在人MSC中基因沉默MTA1是否会重编程肿瘤微环境以抑制TNBC进展和远处转移。
方法：将人MSC用MTA1-shRNA或加扰对照稳定转染。通过qPCR和免疫印迹确认敲低。功能实验包括MMP-2活性、成骨分化标志物（RUNX2、DMP1）、内皮管形成，以及TNBC（MDA-MB-231）三维球体迁移、侵袭和EMT分析。在NSG小鼠中建立原位MSC-TNBC球体共植入（n=5-8/组），以评估肿瘤生长、肺和脑转移，以及组织学EMT和增殖标志物。使用宏转移评分、H&E染色、IHC以及肺和全身的micro-CT对转移进行定量。
结果：MTA1敲低使MSC-MTA1表达降低>80%，并使MMP-2活性抑制66%。成骨分化明显减少（RUNX2和DMP1各下降>60%），血管生成管形成减少61%。在三维共培养中，MTA1-KD的MSC使TNBC迁移减少（下降54%）和侵袭减少（下降57%），并诱导EMT逆转，伴随E-cadherin增加以及Vimentin和Snail减少。在体内，MTA1-KD的MSC显著抑制肿瘤生长（在第56天减少约48%）。肺和脑转移大幅减少，肺微转移灶减少93%，并通过宏转移评分、H&E、IHC和micro-CT成像得到验证。肿瘤和转移病灶显示Ki-67、N-cadherin和Vimentin减少，证实增殖和EMT信号受损。
结论：我们的数据揭示MTA1作为转移能力的主要基质决定因子，在MSC中抑制它可显著抑制驱动EMT、侵袭和器官趋向性定植的肿瘤-基质串扰。肺和脑转移的显著减少——通过宏观、组织学、免疫表型和成像平台得到验证——凸显了靶向基质表观遗传程序而非仅靶向肿瘤细胞所获得的治疗优势。这些发现提名基质MTA1抑制作为一种强大的、机制上有依据的策略，以重塑转移生态位，并为工程化基于MSC的干预措施治疗高危TNBC提供了强有力的转化策略。
查看英文原文 English abstract
Background: Metastasis-associated protein-1 (MTA1) is a chromatin regulator that drives epithelial-to-mesenchymal transition (EMT), invasion, and metastatic competence in aggressive cancers including triple-negative breast cancer (TNBC). While tumor-cell MTA1 roles are well documented, its stromal contribution within mesenchymal stem cells (MSCs)-key regulators of the tumor microenvironment-remains largely unexplored. We investigated whether genetic silencing of MTA1 in human MSCs reprograms the tumor microenvironment to restrain TNBC progression and distant metastasis.
Methods: Human MSCs were stably transfected with MTA1-shRNA or scrambled control. Knockdown was confirmed by qPCR and immunoblotting. Functional assays included MMP-2 activity, osteogenic differentiation markers (RUNX2, DMP1), endothelial tube formation, and TNBC (MDA-MB-231) 3D spheroid migration, invasion, and EMT profiling. Orthotopic MSC-TNBC spheroid co-implants were established in NSG mice (n=5-8/group) to assess tumor growth, lung and brain metastases, and histologic EMT and proliferation markers. Metastasis was quantified using macrometastatic scoring, H&E staining, IHC, and micro-CT of the lungs and whole body.
Results: MTA1 knockdown reduced MSC-MTA1 expression by >80% and suppressed MMP-2 activity by 66%. Osteogenic differentiation was markedly reduced (RUNX2 and DMP1 each ↓>60%), and angiogenic tube formation decreased by 61%. In 3D co-culture, MTA1-KD MSCs reduced TNBC migration (↓54%) and invasion (↓57%) and induced EMT reversal with increased E-cadherin and decreased Vimentin and Snail. In vivo, MTA1-KD MSCs significantly inhibited tumor growth (~48% reduction at day 56). Lung and brain metastases were profoundly reduced, with a 93% decrease in lung micrometastatic foci validated by macrometastasis scoring, H&E, IHC, and micro-CT imaging. Tumors and metastatic lesions showed reduced Ki-67, N-cadherin, and Vimentin, confirming impaired proliferation and EMT signaling.
Conclusion: Our data reveal that MTA1 acts as a master stromal determinant of metastatic competence and that its suppression in MSCs yields marked inhibition of tumor-stroma crosstalk driving EMT, invasion, and organotropic colonization. The profound reduction of lung and brain metastases-validated across macroscopic, histologic, immunophenotypic, and imaging platforms-highlights the therapeutic leverage gained by targeting stromal epigenetic programs rather than tumor cells alone. These findings nominate stromal MTA1 inhibition as a powerful, mechanistically grounded strategy to remodel the metastatic niche and provide a strong translational strategy for engineering MSC-based interventions for high-risk TNBC.
利益披露 Disclosure
A. Mutahar, None..
B. Salimath, None.