Purpose

Fibroblast growth factor receptors (FGFR) and pathways are important players in breast cancer (BC) development. They are commonly altered, and BCs exhibiting FGFR gene amplification are currently being studied for drug development. Here, we aimed to compare the effects of three FGFR inhibitors (FGFRis), i.e., non-selective TKI258 and selective BGJ398 and AZD4547, on different BC-derived cell lines (BCCs) and primary tissues.

Methods

The human BCCs MCF-7 and MDA-MB-231(SA) (wild-type FGFR) and MFM223 (amplified FGFR1 and FGFR2) were analyzed for FGFR expression using qRT-PCR, and the effects of FGFRis on FGFR signaling by Western blotting. The effects of FGFRis on proliferation, viability, migration and invasion of BCCs were assessed in 2D cultures using live-cell imaging, and in 3D cultures using phenotypic analysis of organoids. To study radio-sensitization, FGFRi treatment was combined with irradiation. Patient-derived BC samples were treated with FGFRis in explant cultures and immunostained for Ki67 and cleaved caspase 3.

Results

We found that all FGFRis tested decreased the growth and viability of BC cells in 2D and 3D cultures. BGJ398 and AZD4547 were found to be potent at low concentrations in FGFR-amplified MFM233 cells, whereas higher concentrations were required in non-amplified MCF7 and MDA-MB-231(SA) cells. TKI258 inhibited the migration and invasion, whereas BGJ398 and AZD4547 only inhibited the invasion of MDA-MB-231(SA) cells. FGFRi treatment of MCF7 and MFM223 cells enhanced the inhibitory effect of radiotherapy, but this effect was not observed in MDA-MB-231(SA) cells. FGFRi-treated primary BC explants with moderate FGFR levels showed a tendency towards decreased proliferation and increased apoptosis.

Conclusions

Our results indicate that, besides targeting FGFR-amplified BCs with selective FGFRis, also BCs without FGFR amplification/activation may benefit from FGFRi-treatment. Combination with other treatment modalities, such as radiotherapy, may allow the use of FGFRis at relatively low concentrations and, thereby, contribute to better BC treatment outcomes.

中文翻译：

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FGFR 抑制剂 TKI258、BGJ398 和 AZD4547 对 2D、3D 和组织外植体培养中乳腺癌细胞的影响

目的

成纤维细胞生长因子受体 (FGFR) 和通路是乳腺癌 (BC) 发展的重要参与者。它们通常被改变，目前正在研究显示 FGFR 基因扩增的 BCs 以用于药物开发。在这里，我们旨在比较三种 FGFR 抑制剂 (FGFRis)，即非选择性 TKI258 和选择性 BGJ398 和 AZD4547，对不同 BC 衍生细胞系 (BCC) 和原代组织的影响。

方法

使用 qRT-PCR 分析人类 BCCs MCF-7 和 MDA-MB-231(SA)（野生型FGFR）和 MFM223（扩增的FGFR1和FGFR2）的 FGFR 表达，并通过蛋白质印迹分析 FGFRis 对 FGFR 信号传导的影响. FGFRis 对 BCC 增殖、活力、迁移和侵袭的影响在 2D 培养物中使用活细胞成像进行评估，在 3D 培养物中使用类器官的表型分析进行评估。为了研究放射致敏作用，FGFRi 治疗与辐射相结合。患者来源的 BC 样本在外植体培养物中用 FGFRis 处理，并对 Ki67 和裂解的半胱天冬酶 3 进行免疫染色。

结果

我们发现所有测试的 FGFRi 都降低了 2D 和 3D 培养物中 BC 细胞的生长和活力。发现 BGJ398 和 AZD4547 在FGFR扩增的 MFM233 细胞中以低浓度有效，而在未扩增的 MCF7 和 MDA-MB-231(SA) 细胞中需要更高的浓度。TKI258 抑制迁移和侵袭，而 BGJ398 和 AZD4547 仅抑制 MDA-MB-231(SA) 细胞的侵袭。MCF7 和 MFM223 细胞的 FGFRi 处理增强了放疗的抑制作用，但在 MDA-MB-231(SA) 细胞中未观察到这种作用。具有中等 FGFR 水平的 FGFRi 处理的初级 BC 外植体显示出增殖减少和细胞凋亡增加的趋势。

结论

我们的结果表明，除了用选择性 FGFRi靶向FGFR扩增的 BCs 外，没有 FGFR 扩增/激活的 BCs 也可能受益于 FGFRi 处理。与其他治疗方式（如放疗）相结合，可能允许使用相对低浓度的 FGFRi，从而有助于获得更好的 BC 治疗结果。