De Palma Fatima Domenica Elisa, Pol Jonathan G, Carbonnier Vincent, Scuderi Sarah Adriana, Mannino Deborah, Montégut Léa, Sauvat Allan, Perez-Lanzon Maria, Uribe-Carretero Elisabet, Guarracino Mario, Granata Ilaria, Calogero Raffaele, Del Monaco Valentina, Montanaro Donatella, Stoll Gautier, Botti Gerardo, D'Aiuto Massimiliano, Baldi Alfonso, D'Argenio Valeria, Guigó Roderic, Rezsohazy René, Kroemer Guido, Maiuri Maria Chiara, Salvatore Francesco
CEINGE-Biotecnologie Avanzate Franco Salvatore, Naples, Italy.
Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy.
Cell Death Differ. 2025 Apr;32(4):730-744. doi: 10.1038/s41418-024-01430-2. Epub 2025 Jan 20.
Accumulating evidence suggests that genetic and epigenetic biomarkers hold potential for enhancing the early detection and monitoring of breast cancer (BC). Epigenetic alterations of the Homeobox A2 (HOXA2) gene have recently garnered significant attention in the clinical management of various malignancies. However, the precise role of HOXA2 in breast tumorigenesis has remained elusive. To address this point, we conducted high-throughput RNA sequencing and DNA methylation array studies on laser-microdissected human BC samples, paired with normal tissue samples. Additionally, we performed comprehensive in silico analyses using large public datasets: TCGA and METABRIC. The diagnostic performance of HOXA2 was calculated by means of receiver operator characteristic curves. Its prognostic significance was assessed through immunohistochemical studies and Kaplan-Meier Plotter database interrogation. Moreover, we explored the function of HOXA2 and its role in breast carcinogenesis through in silico, in vitro, and in vivo investigations. Our work revealed significant hypermethylation and downregulation of HOXA2 in human BC tissues. Low HOXA2 expression correlated with increased BC aggressiveness and unfavorable patient survival outcomes. Suppression of HOXA2 expression significantly heightened cell proliferation, migration, and invasion in BC cells, and promoted tumor growth in mice. Conversely, transgenic HOXA2 overexpression suppressed these cellular processes and promoted apoptosis of cancer cells. Interestingly, a strategy of pharmacological demethylation successfully restored HOXA2 expression in malignant cells, reducing their neoplastic characteristics. Bioinformatics analyses, corroborated by in vitro experimentations, unveiled a novel implication of HOXA2 in the lipid metabolism of BC. Specifically, depletion of HOXA2 leaded to a concomitantly decreased expression of PPARγ and its target CIDEC, a master regulator of lipid droplet (LD) accumulation, thereby resulting in reduced LD abundance in BC cells. In summary, our study identifies HOXA2 as a novel prognosis-relevant tumor suppressor in the mammary gland.
越来越多的证据表明，基因和表观遗传生物标志物在加强乳腺癌（BC）的早期检测和监测方面具有潜力。同源框A2（HOXA2）基因的表观遗传改变最近在各种恶性肿瘤的临床管理中受到了广泛关注。然而，HOXA2在乳腺肿瘤发生中的具体作用仍不清楚。为了解决这一问题，我们对激光显微切割的人BC样本及其配对的正常组织样本进行了高通量RNA测序和DNA甲基化阵列研究。此外，我们使用大型公共数据集（TCGA和METABRIC）进行了全面的计算机分析。通过受试者工作特征曲线计算HOXA2的诊断性能。通过免疫组织化学研究和Kaplan-Meier Plotter数据库查询评估其预后意义。此外，我们通过计算机、体外和体内研究探索了HOXA2的功能及其在乳腺癌发生中的作用。我们的研究发现，人BC组织中HOXA2存在显著的高甲基化和下调。HOXA2低表达与BC侵袭性增加和患者生存结果不良相关。抑制HOXA2表达显著增强了BC细胞的增殖、迁移和侵袭，并促进了小鼠肿瘤的生长。相反，转基因HOXA2过表达抑制了这些细胞过程，并促进了癌细胞的凋亡。有趣的是，药物去甲基化策略成功地恢复了恶性细胞中HOXA2的表达，降低了它们的肿瘤特性。体外实验证实的生物信息学分析揭示了HOXA2在BC脂质代谢中的新作用。具体而言，HOXA2的缺失导致PPARγ及其靶标CIDEC（脂滴（LD）积累的主要调节因子）的表达随之降低，从而导致BC细胞中LD丰度降低。总之，我们的研究将HOXA2确定为乳腺中一种新的与预后相关的肿瘤抑制因子。
