Wang Wen-Ke, Lin Hui-Yu, Lin Che-Hsuan, Lee Hsun-Hua, Chen Yen-Lin, Lin Yu-Hsien Kent, Chiu Hui-Wen, Sheen-Chen Shry-Ming, Lin Yuan-Feng
Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, 11031, Taiwan.
Department of Surgery, Taipei Medical University Hospital, Taipei Medical University, Taipei, 11031, Taiwan.
Breast Cancer Res. 2024 Dec 31;26(1):193. doi: 10.1186/s13058-024-01953-z.
Triple negative breast cancer (TNBC) belongs to the worst prognosis of breast cancer subtype probably because of distant metastasis to other organs, e.g. lungs. However, the mechanism underlying TNBC metastasis remains largely unknown.
Bioinformatics analysis was conducted to evaluate the mRNA/protein expression and prognostic significance of G protein-coupled receptor kinase 6 (GRK6) in BC subtypes. RT-PCR assays were used to test the GRK6 expression in human BC tissues and cell lines. The in vitro cellular migration and in vivo lung colony-forming assays were established to estimate the metastatic potentials of TNBC cells. Western blotting was employed to examine protein phosphorylation, translocation and expression in the designed experiments.
Here we show that GRK6 upregulation is extensively detected in TNBC compared to normal mammary tissues and other BC subtypes and correlates with an increased risk for distant metastasis in TNBC patients. GRK6 knockdown suppressed but overexpression potentiated the cellular migration and lung colony-forming abilities of TNBC cells. Moreover, our data demonstrated that the posttranslational palmitoylation of GRK6 is extremely critical for activating β-Arrestin 2/mitogen-activated protein kinases (MAPKs)/NF-κB signaling axis and fostering the metastatic potentials of TNBC cells. Accordingly, the pharmaceutical inhibition of GRK6 kinase activity dramatically suppressed the activation of β-Arrestin 2, MAPKs and NF-κB and the cellular migration ability of highly metastatic MDA-MB231 cells. Sequentially blocking the β-Arrestin 2/MAPKs/NF-κB axis with their inhibitors predominantly mitigated the GRK6-promoted migration ability of poorly metastatic HCC1937 cells.
Our results not only provide a novel mechanism for TNBC metastasis but also offer a new therapeutic strategy to combat metastatic TNBC via targeting GRK6 activity.
三阴性乳腺癌（TNBC）可能因其向其他器官（如肺）的远处转移而属于乳腺癌亚型中预后最差的类型。然而，TNBC转移的潜在机制在很大程度上仍不清楚。
进行生物信息学分析以评估G蛋白偶联受体激酶6（GRK6）在乳腺癌亚型中的mRNA/蛋白表达及预后意义。采用逆转录-聚合酶链反应（RT-PCR）检测人乳腺癌组织和细胞系中GRK6的表达。建立体外细胞迁移和体内肺集落形成试验以评估TNBC细胞的转移潜能。在设计的实验中采用蛋白质免疫印迹法检测蛋白质磷酸化、转位和表达。
我们发现，与正常乳腺组织和其他乳腺癌亚型相比，TNBC中广泛检测到GRK6上调，且与TNBC患者远处转移风险增加相关。GRK6敲低抑制但过表达增强TNBC细胞的迁移和肺集落形成能力。此外，我们的数据表明，GRK6的翻译后棕榈酰化对于激活β-抑制蛋白2/丝裂原活化蛋白激酶（MAPKs）/核因子κB（NF-κB）信号轴以及促进TNBC细胞的转移潜能极其关键。因此，GRK6激酶活性的药物抑制显著抑制了β-抑制蛋白2、MAPKs和NF-κB的激活以及高转移性MDA-MB231细胞的细胞迁移能力。依次用其抑制剂阻断β-抑制蛋白2/MAPKs/NF-κB轴主要减轻了GRK6促进的低转移性HCC1937细胞的迁移能力。
我们的结果不仅为TNBC转移提供了一种新机制，还通过靶向GRK6活性为对抗转移性TNBC提供了一种新的治疗策略。
