de la Peña Avalos Bárbara, Tropée Romain, Duijf Pascal H G, Dray Eloïse
University of Texas Health Science Center at San Antonio.
Queensland University of Technology.
Res Sq. 2023 May 15:rs.3.rs-2917471. doi: 10.21203/rs.3.rs-2917471/v1.
The Eyes Absent (EYA) family of proteins is an atypical group of four dual-functioning protein phosphatases, which have been linked to many vital cellular processes and organogenesis pathways. Like the other isoforms, EYA4 possesses transcriptional activation and phosphatase functions, with serine/threonine and tyrosine phosphatase domains. EYA4 has been associated with several human cancers, with tumor-suppressing and tumor-promoting roles. However, EYA4 is the least well-characterized member of this unique family of phosphatases, with its biological functions and molecular mechanisms in cancer progression, particularly in breast cancer, still largely unknown. In the present study, we found that the over-expression of EYA4 in breast tissue leads to an aggressive and invasive breast cancer phenotype, while the inhibition of EYA4 reduced tumorigenic properties of breast cancer cells and . Cellular changes downstream of EYA4, including cell proliferation and migration, may explain the increased metastatic power of breast cancer cells over-expressing EYA4. Mechanistically, EYA4 prevents genome instability by inhibiting the accumulation of replication-associated DNA damage. Its depletion results in polyploidy as a consequence of endoreplication, a phenomenon that can occur in response to stress. The absence of EYA4 leads to spontaneous replication stress characterized by the activation of the ATR pathway, sensitivity to hydroxyurea, and accumulation of endogenous DNA damage as indicated by increased γH2AX levels. In addition, we show that EYA4, specifically its serine/threonine phosphatase domain, plays an important and so far, unexpected role in replication fork progression. This phosphatase activity is essential for breast cancer progression and metastasis. Taken together, our data indicate that EYA4 is a novel breast cancer oncogene that supports primary tumor growth and metastasis. Developing therapeutics aimed at the serine/threonine phosphatase activity of EYA4 represents a robust strategy for killing breast cancer cells, to limit metastasis and overcome chemotherapy resistance caused by endoreplication and genomic rearrangements.
无眼（EYA）蛋白家族是一组由四种具有双重功能的非典型蛋白磷酸酶组成的蛋白，它们与许多重要的细胞过程和器官发生途径有关。与其他亚型一样，EYA4具有转录激活和磷酸酶功能，含有丝氨酸/苏氨酸和酪氨酸磷酸酶结构域。EYA4与多种人类癌症相关，具有肿瘤抑制和肿瘤促进作用。然而，EYA4是这个独特的磷酸酶家族中特征最少的成员，其在癌症进展，尤其是乳腺癌中的生物学功能和分子机制仍 largely 未知。在本研究中，我们发现 EYA4 在乳腺组织中的过表达导致侵袭性乳腺癌表型，而抑制 EYA4 则降低了乳腺癌细胞的致瘤特性。EYA4 下游的细胞变化，包括细胞增殖和迁移，可能解释了过表达 EYA4 的乳腺癌细胞转移能力的增加。从机制上讲，EYA4 通过抑制复制相关 DNA 损伤的积累来防止基因组不稳定。其缺失导致因核内复制而产生的多倍体，这是一种可因应激而发生的现象。EYA4 的缺失导致以 ATR 途径激活、对羟基脲敏感以及 γH2AX 水平升高所表明的内源性 DNA 损伤积累为特征的自发复制应激。此外，我们表明 EYA4，特别是其丝氨酸/苏氨酸磷酸酶结构域，在复制叉进展中发挥了重要且迄今为止意想不到的作用。这种磷酸酶活性对于乳腺癌进展和转移至关重要。综上所述，我们的数据表明 EYA4 是一种新型乳腺癌癌基因，支持原发性肿瘤生长和转移。开发针对 EYA4 丝氨酸/苏氨酸磷酸酶活性的疗法是杀死乳腺癌细胞、限制转移并克服由核内复制和基因组重排引起的化疗耐药性的有力策略。
