Department of Anesthesiology, Huizhou Municipal Central Hospital, Huizhou, 516001, China.
Department of Anesthesiology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, Guangzhou, 510060, China.
BMC Cancer. 2022 Dec 2;22(1):1248. doi: 10.1186/s12885-022-10368-y.
Dopamine receptors have been reported to play important roles in cancer progression. However, the role of dopamine receptor D3 (DRD3) in hepatocellular carcinoma (HCC) remains unclear.
The expression of DRD3 was detected by immunohistochemistry and real-time qPCR. The prognostic value of DRD3 in patients was investigated by analyzing selected databases, including cBioPortal and Kaplan-Meier plotter. Cell growth was tested by CCK8 assay, and Transwell assays were performed to assess cancer cell migration and invasion. The cAMP/ERK/CREB signaling pathway was evaluated by Western blot analysis and ELISA. An HCC xenograft model was established for in vivo experiments.
DRD3 mRNA expression was significantly higher in nontumor tissues than in tumor tissues. Lower protein expression of DRD3 was related to poor recurrence-free survival (RFS) and overall survival (OS). Kaplan-Meier plotter analysis showed that higher expression of DRD3 mRNA was associated with better OS, RFS, disease-specific survival (DSS), and progression-free survival (PFS). cBioPortal analysis revealed that the alteration group, which harbored genetic mutations in DRD3, exhibited poor OS, RFS, DSS and PFS. According to CCK8 and Transwell assays, stable DRD3 overexpression cell line (ex-DRD3-SK-HEP-1) showed weaker proliferation, migration and invasion behaviors. PD128907, a DRD3 agonist, suppressed proliferation, migration and invasion in HCC cell lines, while U99194, a DRD3 antagonist, enhanced proliferation, migration and invasion in HCC cell lines. Western blot analysis and ELISA revealed that stable DRD3 knock-down cell line (sh-DRD3-PLC/PRF/5) and U99194 both increased the protein levels of cAMP, p-ERK and p-CREB; on the other hand, ex-DRD3-SK-HEP-1 and PD128907 decreased the protein levels of cAMP, p-ERK and p-CREB. SCH772984, an ERK antagonist, abolished the effect of U99194 on the malignant biological behaviors of HCC cells. In vivo, PD128907 suppressed tumor growth, and U99194 enhanced tumor growth.
Our results suggest that down-regulation of DRD3 is strongly involved in the progression of HCC, and DRD3 might be consider as an independent prognostic factor for HCC. Furthermore, DRD3 agonists may be a promising strategy for HCC therapy.
多巴胺受体已被报道在癌症进展中发挥重要作用。然而，多巴胺受体 D3（DRD3）在肝细胞癌（HCC）中的作用尚不清楚。
通过免疫组织化学和实时 qPCR 检测 DRD3 的表达。通过分析包括 cBioPortal 和 Kaplan-Meier plotter 在内的选定数据库，研究 DRD3 在患者中的预后价值。通过 CCK8 测定和 Transwell 测定检测细胞生长，评估癌细胞迁移和侵袭。通过 Western blot 分析和 ELISA 评估 cAMP/ERK/CREB 信号通路。建立 HCC 异种移植模型进行体内实验。
DRD3 mRNA 表达在非肿瘤组织中明显高于肿瘤组织。DRD3 蛋白表达水平较低与无复发生存（RFS）和总生存（OS）不良相关。Kaplan-Meier plotter 分析显示，DRD3 mRNA 高表达与更好的 OS、RFS、疾病特异性生存（DSS）和无进展生存（PFS）相关。cBioPortal 分析显示，DRD3 发生基因突变的改变组 OS、RFS、DSS 和 PFS 不良。根据 CCK8 和 Transwell 测定，稳定过表达 DRD3 的细胞系（ex-DRD3-SK-HEP-1）表现出较弱的增殖、迁移和侵袭行为。DRD3 激动剂 PD128907 抑制 HCC 细胞系的增殖、迁移和侵袭，而 DRD3 拮抗剂 U99194 增强 HCC 细胞系的增殖、迁移和侵袭。Western blot 分析和 ELISA 显示，稳定敲低 DRD3 的细胞系（sh-DRD3-PLC/PRF/5）和 U99194 均增加了 cAMP、p-ERK 和 p-CREB 的蛋白水平；另一方面，ex-DRD3-SK-HEP-1 和 PD128907 降低了 cAMP、p-ERK 和 p-CREB 的蛋白水平。ERK 拮抗剂 SCH772984 消除了 U99194 对 HCC 细胞恶性生物学行为的影响。体内，PD128907 抑制肿瘤生长，而 U99194 促进肿瘤生长。
我们的结果表明，DRD3 的下调强烈参与 HCC 的进展，DRD3 可能被视为 HCC 的独立预后因素。此外，DRD3 激动剂可能是 HCC 治疗的一种有前途的策略。
