大多数乳腺癌死亡是由转移引起的。我们之前报道过 DNA 修复因子和组蛋白伴侣 Aprataxin PNK 样因子 (APLF) 参与三阴性乳腺癌 (TNBC) 细胞的 EMT 相关转移。然而，非转移细胞也表达 APLF，其对疾病进展的影响仍不确定。在这里，我们证明乳腺癌细胞的转移预后可能由 APLF 的细胞定位决定。使用 TNBC 患者样本和细胞系，我们发现 APLF 定位于细胞核和细胞质，而乳腺癌的其他亚型则定位于细胞质或核周。为了研究体外和体内的转移特性，我们通过在不存在假定的 APLF NLS 的情况下在管腔亚型 MCF7 细胞中稳定产生 APLF 标记的核定位信号 (NLS) 来模拟 APLF 差异定位。非转移性 MCF7 细胞中的核 APLF 表现出明显的迁移、侵袭和转移潜力。我们从分子研究中获得了以下机制：PARP1 可以促进 APLF 从细胞质转运至细胞核，协助与 EMT 相关的 TNBC 细胞的转移。用奥拉帕尼抑制 PARP1 酶活性会消除 APLF 的核表达，并导致与 EMT 相关的基因表达丧失。因此，我们的研究结果表明，APLF 的细胞定位可以预测乳腺癌转移的风险，因此可以用来确定疾病进展。我们预计，抑制胞质 PARP1-APLF 相互作用可能有助于预防 TNBC 患者的乳腺癌转移。版权所有 © 2024 Elsevier B.V. 保留所有权利。

Most breast cancer deaths result from metastases. We previously reported that DNA repair factor and histone chaperone Aprataxin PNK-like Factor (APLF) is involved in EMT-associated metastasis of triple negative breast cancer (TNBC) cells. However, non-metastatic cells also expressed APLF, the implications of which in disease advancement remain uncertain. Here, we demonstrate that the metastatic prognosis of breast cancer cells may be determined by the cellular localization of APLF. Using TNBC patient samples and cell lines, we discovered that APLF was localized in the nucleus and cytoplasm, whereas other subtypes of breast cancer had cytosolic or perinuclear localization. To investigate metastatic properties in vitro and in vivo, we modeled APLF differential localization by stably producing APLF-tagged nuclear localization signal (NLS) in the luminal subtype MCF7 cells in the absence of putative APLF NLS. Nuclear APLF in non-metastatic MCF7 cells demonstrated pronounced migration, invasion and metastatic potential. We obtained the mechanistic insight from molecular studies that PARP1 could facilitate the transport of APLF from the cytosol to the nucleus, assisting in the metastasis of TNBC cells linked with EMT. Inhibition of PARP1 enzymatic activity with olaparib abrogated the nuclear expression of APLF with loss in expression of genes associated with EMT. Thus, our findings reveal that cellular localization of APLF may predict the risk of breast cancer to metastasize and hence could be exploited to determine the disease progression. We anticipate that the inhibition of cytosolic PARP1-APLF interaction may potentially aid in the prevention of breast cancer metastasis in TNBC patients.Copyright © 2024 Elsevier B.V. All rights reserved.