Department of Pathology, Affiliated Tumor Hospital of Nantong University, No.30 North Tongyang Road, Pingchao, Nantong, 226361, Jiangsu, China.
Department of Head and Neck Surgery, Affiliated Tumor Hospital of Nantong University, No.30 North Tongyang Road, Pingchao, Nantong, 226361, Jiangsu, China.
Breast Cancer Res. 2024 Jun 5;26(1):92. doi: 10.1186/s13058-024-01845-2.
Identifying new targets in triple negative breast cancer (TNBC) remains critical. REG3A (regenerating islet-derived protein 3 A), a calcium-dependent lectin protein, was thoroughly investigated for its expression and functions in breast cancer.
Bioinformatics and local tissue analyses were employed to identify REG3A expression in breast cancer. Genetic techniques were employed to modify REG3A expression, and the resulting effects on the behaviors of breast cancer cells were examined. Subcutaneous xenograft models were established to investigate the involvement of REG3A in the in vivo growth of breast cancer cells.
Analysis of the TCGA database uncovered increased REG3A levels in human breast cancer tissues. Additionally, REG3A mRNA and protein levels were elevated in TNBC tissues of locally treated patients, contrasting with low expression in adjacent normal tissues. In primary human TNBC cells REG3A shRNA notably hindered cell proliferation, migration, and invasion while triggering caspase-mediated apoptosis. Similarly, employing CRISPR-sgRNA for REG3A knockout showed significant anti-TNBC cell activity. Conversely, REG3A overexpression bolstered cell proliferation and migration. REG3A proved crucial for activating the Akt-mTOR cascade, as evidenced by decreased Akt-S6K1 phosphorylation upon REG3A silencing or knockout, which was reversed by REG3A overexpression. A constitutively active mutant S473D Akt1 (caAkt1) restored Akt-mTOR activation and counteracted the proliferation inhibition and apoptosis induced by REG3A knockdown in breast cancer cells. Crucially, REG3A played a key role in maintaining mTOR complex integrity. Bioinformatics identified zinc finger protein 680 (ZNF680) as a potential REG3A transcription factor. Knocking down or knocking out ZNF680 reduced REG3A expression, while its overexpression increased it in primary breast cancer cells. Additionally, enhanced binding between ZNF680 protein and the REG3A promoter was observed in breast cancer tissues and cells. In vivo, REG3A shRNA significantly inhibited primary TNBC cell xenograft growth. In REG3A-silenced xenograft tissues, reduced REG3A levels, Akt-mTOR inhibition, and activated apoptosis were evident.
ZNF680-caused REG3A overexpression drives tumorigenesis in breast cancer possibly by stimulating Akt-mTOR activation, emerging as a promising and innovative cancer target.
在三阴性乳腺癌（TNBC）中鉴定新的靶点仍然至关重要。REG3A（再生胰岛衍生蛋白 3A）是一种钙依赖性凝集素蛋白，其在乳腺癌中的表达和功能已被深入研究。
采用生物信息学和局部组织分析方法鉴定乳腺癌中 REG3A 的表达。采用基因技术修饰 REG3A 的表达，观察其对乳腺癌细胞行为的影响。建立皮下异种移植模型，研究 REG3A 在乳腺癌细胞体内生长中的作用。
TCGA 数据库分析显示，人乳腺癌组织中 REG3A 水平升高。此外，局部治疗的 TNBC 患者组织中 REG3A mRNA 和蛋白水平升高，而相邻正常组织中表达水平较低。在原发性人 TNBC 细胞中，REG3A shRNA 显著抑制细胞增殖、迁移和侵袭，同时触发半胱天冬酶介导的细胞凋亡。同样，采用 CRISPR-sgRNA 敲除 REG3A 显示出显著的抗 TNBC 细胞活性。相反，REG3A 过表达增强了细胞增殖和迁移。REG3A 被证明对激活 Akt-mTOR 级联反应至关重要，因为 REG3A 沉默或敲除后 Akt-S6K1 磷酸化减少，而 REG3A 过表达则逆转了这一现象。组成型激活的 Akt1（caAkt1）突变体恢复了 Akt-mTOR 的激活，并抵消了 REG3A 敲低对乳腺癌细胞增殖抑制和凋亡的诱导作用。至关重要的是，REG3A 在维持 mTOR 复合物完整性方面发挥了关键作用。生物信息学鉴定锌指蛋白 680（ZNF680）为 REG3A 的潜在转录因子。在原发性乳腺癌细胞中，敲低或敲除 ZNF680 降低了 REG3A 的表达，而过表达 ZNF680 则增加了 REG3A 的表达。此外，在乳腺癌组织和细胞中观察到 ZNF680 蛋白与 REG3A 启动子之间的结合增强。在体内，REG3A shRNA 显著抑制原发性 TNBC 细胞异种移植的生长。在 REG3A 沉默的异种移植组织中，REG3A 水平降低、Akt-mTOR 抑制和激活的细胞凋亡明显。
ZNF680 引起的 REG3A 过表达可能通过刺激 Akt-mTOR 的激活来驱动乳腺癌的肿瘤发生，成为一种有前途和创新的癌症靶点。
