Department of Biochemistry and Molecular Biology, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100005, China.
Weifang Medical University, Weifang, 261000, China.
Cell Commun Signal. 2018 Oct 4;16(1):65. doi: 10.1186/s12964-018-0267-5.
Our previous work revealed that rhomboid domain-containing protein 1 (RHBDD1) participates in the modulation of cell growth and apoptosis in colorectal cancer cells. This study aimed to investigate the function of RHBDD1 in regulating breast cancer progression and its underlying molecular basis.
Immunohistochemistry was performed to evaluate RHBDD1 expression in 116 breast cancer tissue and 39 adjacent normal tissue and expression of RHBDD1, phospho-Akt (p-Akt) and cyclin-dependent kinase 2 (CDK2) in the same 84 breast cancer specimens. RHBDD1-knock-out cells were established using breast cancer cell lines. In vitro studies were carried out to estimate the function of RHBDD1 in cell proliferation, migration and invasion. Fluorescence microscopy assay and flow cytometric analysis were used to measure apoptosis and cell cycle regulation. RNA sequencing and western blot analysis were used to investigate the molecular mechanisms of RHBDD1.
RHBDD1 was highly up-regulated in breast cancer tissue compared with that in normal tissue and associated with pathological tumor (pT) stage, pathological tumor-node-metastasis (pTNM) stage and estrogen receptor (ER) expression. RHBDD1 up-regulation was associated with poor prognosis in several subtypes of breast cancer. Deletion of RHBDD1 promoted apoptosis and suppressed proliferation, migration and invasion in breast cancer cells. RHBDD1 deletion suppressed Akt activation and decreased CDK2 protein level via proteasome pathway, thus inhibited cell cycle progression and G1/S phase transition. Moreover, the protein level of RHBDD1, p-Akt and CDK2 was significantly positively correlated in breast cancer tissue.
Our study reveals that RHBDD1 promotes breast cancer progression by regulating p-Akt and CDK2 protein levels, and might be a potential biomarker and prognostic indicator for breast cancer patients.
我们之前的工作表明，菱形结构域蛋白 1（RHBDD1）参与调节结直肠癌细胞的生长和凋亡。本研究旨在探讨 RHBDD1 在调节乳腺癌进展中的作用及其潜在的分子基础。
采用免疫组织化学法检测 116 例乳腺癌组织和 39 例癌旁正常组织中 RHBDD1 的表达，并检测 84 例乳腺癌组织中 RHBDD1、磷酸化 Akt（p-Akt）和周期蛋白依赖性激酶 2（CDK2）的表达。利用乳腺癌细胞系建立 RHBDD1 敲除细胞。进行体外研究以评估 RHBDD1 在细胞增殖、迁移和侵袭中的功能。荧光显微镜检测和流式细胞术分析用于测量细胞凋亡和细胞周期调控。RNA 测序和 Western blot 分析用于研究 RHBDD1 的分子机制。
与正常组织相比，RHBDD1 在乳腺癌组织中高表达，与病理肿瘤（pT）分期、病理肿瘤-淋巴结-转移（pTNM）分期和雌激素受体（ER）表达相关。RHBDD1 上调与多种乳腺癌亚型的不良预后相关。RHBDD1 缺失促进乳腺癌细胞凋亡，抑制增殖、迁移和侵袭。RHBDD1 缺失通过蛋白酶体途径抑制 Akt 激活和降低 CDK2 蛋白水平，从而抑制细胞周期进程和 G1/S 期转换。此外，乳腺癌组织中 RHBDD1、p-Akt 和 CDK2 的蛋白水平呈显著正相关。
本研究表明，RHBDD1 通过调节 p-Akt 和 CDK2 蛋白水平促进乳腺癌进展，可能是乳腺癌患者的潜在生物标志物和预后指标。
