Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, P. R. China.
Breast Tumor Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong, P. R. China.
Cancer Commun (Lond). 2023 Nov;43(11):1244-1266. doi: 10.1002/cac2.12495. Epub 2023 Oct 19.
As a rapid-progressing tumor, breast malignant phyllodes tumors (PTs) are challenged by the lack of effective therapeutic strategies and suitable prognostic markers. This study aimed to clarify the role and mechanism of CD146 on promoting PTs malignant progression, and to identify a novel prognosis marker and treatment target of breast malignant PTs.
The expression and prognostic significance of CD146 in PTs was detected through single-cell RNA-sequencing (scRNA-seq), immunostaining, real-time PCR and other methodologies. Functional experiments including proliferation assay, colony formation assay, transwell assay, and collagen contraction assay were conducted to validate the role of CD146 in malignant progression of PTs. The efficacy of anti-CD146 monoclonal antibody AA98 against malignant PTs was corroborated by a malignant PT organoid model and a PT patient-derived xenograft (PDX) model. Transcriptome sequencing, proteomic analysis, co-immunoprecipitation, and pull-down assay was employed to identify the modulating pathway and additional molecular mechanism.
In this study, the scRNA-seq analysis of PTs disclosed a CD146-positive characteristic in the α-SMA fibroblast subset. Furthermore, a progressive elevation in the level of CD146 was observed with the malignant progression of PTs. More importantly, CD146 was found to serve as an independent predictor for recurrence in PT patients. Furthermore, CD146 was found to augment the viability and invasion of PTs. Mechanistically, CD146 acted as a protective "shield" to prevent the degradation of Discoidin, CUB, and LCCL domain-containing protein 2 (DCBLD2), thereby activating the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway and enhancing malignant behaviors of PT cells. In the malignant PT organoid and PDX model, a significant suppression of malignant PT growth was observed after the application of AA98.
These findings suggested that CD146 served as an efficacious marker for predicting PT malignant progression and showed promise as a prognosis marker and treatment target of breast malignant PTs. The study further unveiled the essential role of the CD146-DCBLD2/PI3K/AKT axis in the malignant progression of PTs.
乳腺叶状肿瘤（PTs）是一种快速进展的肿瘤，缺乏有效的治疗策略和合适的预后标志物是其面临的挑战。本研究旨在阐明 CD146 在促进 PTs 恶性进展中的作用和机制，并确定一种新的乳腺恶性 PTs 的预后标志物和治疗靶点。
通过单细胞 RNA 测序（scRNA-seq）、免疫染色、实时 PCR 等方法检测 CD146 在 PTs 中的表达及预后意义。增殖实验、集落形成实验、Transwell 实验和胶原收缩实验等功能实验验证 CD146 在 PTs 恶性进展中的作用。利用恶性 PT 类器官模型和 PT 患者来源异种移植（PDX）模型验证抗 CD146 单克隆抗体 AA98 的疗效。通过转录组测序、蛋白质组分析、共免疫沉淀和下拉实验鉴定调控通路和其他分子机制。
本研究通过 PTs 的 scRNA-seq 分析发现 CD146 在 α-SMA 成纤维细胞亚群中呈阳性特征。此外，随着 PTs 的恶性进展，CD146 的水平逐渐升高。更重要的是，CD146 被发现是 PT 患者复发的独立预测因子。此外，CD146 增强了 PTs 的活力和侵袭性。在机制上，CD146 充当了 Discoidin、CUB 和 LCCL 结构域包含蛋白 2（DCBLD2）的保护性“盾牌”，防止其降解，从而激活磷酸肌醇 3-激酶（PI3K）/蛋白激酶 B（AKT）信号通路，增强 PT 细胞的恶性行为。在恶性 PT 类器官和 PDX 模型中，应用 AA98 后明显抑制了恶性 PT 的生长。
这些发现表明 CD146 可作为预测 PT 恶性进展的有效标志物，并有望成为乳腺恶性 PTs 的预后标志物和治疗靶点。本研究进一步揭示了 CD146-DCBLD2/PI3K/AKT 轴在 PTs 恶性进展中的重要作用。
