Department of Dermatology, University Hospital St. Poelten, Karl Landsteiner University of Health Sciences, A-3100 St. Poelten, Austria.
Department of Internal Medicine III, Division of Gastroenterology and Hepatology, Medical University of Vienna, A-1090 Vienna, Austria.
Int J Oncol. 2021 Sep;59(3). doi: 10.3892/ijo.2021.5250. Epub 2021 Jul 28.
The overexpression of chondroitin sulfate proteoglycan 4 (CSPG4) is associated with several tumor types, including malignant melanoma, squamous cell carcinoma, triple‑negative breast carcinoma, oligodendrocytomas or gliomas. Due to its restricted distribution in normal tissues, CSPG4 has been considered a potential target for several antitumor approaches, including monoclonal antibody (mAb) therapies. The aim of the present study was to characterize the impact of the CSPG4‑specific mAb clone 9.2.27 on its own or in combination with the commonly used BRAF‑selective inhibitor, PLX4032, on different functions of melanoma cells to assess the potential synergistic effects. The BRAF V600‑mutant human melanoma cell lines, M14 (CSPG4‑negative) and WM164 (CSPG4‑positive), were exposed to the CSPG4‑specific 9.2.27 mAb and/or PLX4032. Cell viability and colony formation capacity were evaluated. A 3D‑cell culture spheroid model was used to assess the invasive properties of the treated cells. In addition, flow cytometric analysis of apoptosis and cell cycle analyses were performed. Incubation of the WM164 cell line with CSPG4‑specific 9.2.27 mAb decreased viability, colony formation ability and the invasive capacity of CSPG4‑positive tumor cells, which was not the case for the CSPG4‑negative M14 cell line. Combined treatment of the WM164 cells with 9.2.27 mAb plus PLX4032 did not exert any significant additional effect in comparison to treatment with PLX4032 alone in the clonogenic and invasion assays. M14 cell cycle distribution was not influenced by the CSPG4‑specific 9.2.27 mAb. By contrast, the exposure of WM164 cells to the mAb resulted in an arrest of the cells in the S phase. Moreover, combined treatment of the WM164 cells led to a significantly increased accumulation of cells in the subG1 phase, combined with a decrease of cells in the G2/M phase. On the whole, findings of the present study indicate that the CSPG4‑specific 9.2.27 mAb exerts an anti‑invasive effect on CSPG4‑positive melanoma spheroids, which is not enhanced by BRAF inhibition. These findings provide the basis for further investigations on the effects of anti‑CSPG4‑based treatments of CSPG4‑positive tumors.
硫酸软骨素蛋白聚糖 4（CSPG4）的过表达与多种肿瘤类型相关，包括恶性黑色素瘤、鳞状细胞癌、三阴性乳腺癌、少突胶质细胞瘤或神经胶质瘤。由于其在正常组织中的分布有限，CSPG4 已被认为是几种抗肿瘤方法的潜在靶点，包括单克隆抗体（mAb）治疗。本研究的目的是研究 CSPG4 特异性 mAb 克隆 9.2.27 对 BRAF 选择性抑制剂 PLX4032 的单独或联合作用对不同黑色素瘤细胞功能的影响，以评估潜在的协同作用。将 BRAF V600 突变的人黑色素瘤细胞系 M14（CSPG4 阴性）和 WM164（CSPG4 阳性）暴露于 CSPG4 特异性 9.2.27 mAb 和/或 PLX4032 中。评估细胞活力和集落形成能力。使用 3D 细胞培养球体模型评估处理细胞的侵袭特性。此外，还进行了凋亡和细胞周期分析的流式细胞术分析。用 CSPG4 特异性 9.2.27 mAb 孵育 WM164 细胞系可降低 CSPG4 阳性肿瘤细胞的活力、集落形成能力和侵袭能力，而 CSPG4 阴性 M14 细胞系则并非如此。与单独用 PLX4032 治疗相比，用 9.2.27 mAb 加 PLX4032 联合治疗 WM164 细胞在集落形成和侵袭测定中未产生任何显著的附加作用。CSPG4 特异性 9.2.27 mAb 不影响 M14 细胞的细胞周期分布。相比之下，用该 mAb 孵育 WM164 细胞导致细胞在 S 期停滞。此外，联合治疗 WM164 细胞导致亚 G1 期细胞的显著积累增加，同时 G2/M 期细胞减少。总的来说，本研究的结果表明，CSPG4 特异性 9.2.27 mAb 对 CSPG4 阳性黑色素瘤球体具有抗侵袭作用，而 BRAF 抑制不能增强该作用。这些发现为进一步研究基于抗 CSPG4 的治疗对 CSPG4 阳性肿瘤的影响提供了依据。
