PURPOSE Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with poor survival outcomes. Metformin has been shown to have antitumor effects by lowering serum levels of the mitogen insulin and having pleiotropic effects on cancer cell signaling pathways. BMS-754807 is a potent and reversible inhibitor of both insulin-like growth factor 1 receptor (IGF-1R) and insulin receptor (IR). Both drugs have been reported to have some efficacy in TNBC. However, it is unclear whether the combination of the two drugs is more effective than single drug treatment in TNBC. METHODS We treated a panel of TNBC cell lines with metformin and BMS-754807 alone and in combination and tested cell viability using MTS assays. We used the CompuSyn software to analyze for additivity, synergism, or antagonism. We also examined the molecular mechanism by performing reverse phase protein assay (RPPA) to detect the candidate pathways altered by single drugs and the drug combination and used Western blotting to verify and expand the findings. RESULTS The combination of metformin and BMS-754807 showed synergy in 11 out of 13 TNBC cell lines tested (85%). RPPA analysis detected significant alterations by the drug combination of multiple proteins known to regulate cell cycle and tumor growth. In particular, the drug combination significantly increased levels of total and phosphorylated forms of the cell cycle inhibitor p27Kip1 and decreased the level of the p27Kip1 E3 ligase SCFSkp2. CONCLUSIONS We conclude that the combination of metformin and BMS-754807 is more effective than either drug alone in inhibiting cell proliferation in the majority of TNBC cell lines, and that one important mechanism may be suppression of SCFSkp2 and subsequent stabilization of the cell cycle inhibitor p27Kip1. This combination treatment may represent an effective targeted therapy for a significant subset of TNBC cases and should be further evaluated.

中文翻译：

---

二甲双胍和胰岛素/IGF-1 受体抑制剂在阻断三阴性乳腺癌的生长方面具有协同作用。

目的三阴性乳腺癌 (TNBC) 是一种侵袭性乳腺癌亚型，生存结果较差。二甲双胍已被证明通过降低有丝分裂原胰岛素的血清水平和对癌细胞信号通路具有多效作用而具有抗肿瘤作用。BMS-754807 是一种有效且可逆的胰岛素样生长因子 1 受体 (IGF-1R) 和胰岛素受体 (IR) 抑制剂。据报道，这两种药物对 TNBC 都有一定的疗效。然而，目前尚不清楚两种药物联合治疗是否比单药治疗在 TNBC 中更有效。方法 我们用二甲双胍和 BMS-754807 单独和组合处理一组 TNBC 细胞系，并使用 MTS 分析测试细胞活力。我们使用 CompuSyn 软件来分析可加性、协同作用或拮抗作用。我们还通过执行反相蛋白质测定 (RPPA) 来检测由单一药物和药物组合改变的候​​选途径，并使用蛋白质印迹来验证和扩展发现，从而检验了分子机制。结果二甲双胍和 BMS-754807 的组合在测试的 13 个 TNBC 细胞系中的 11 个（85%）中显示出协同作用。RPPA 分析通过已知可调节细胞周期和肿瘤生长的多种蛋白质的药物组合检测到显着改变。特别是，该药物组合显着增加了细胞周期抑制剂 p27Kip1 的总和磷酸化形式的水平，并降低了 p27Kip1 E3 连接酶 SCFSkp2 的水平。结论 我们得出结论，二甲双胍和 BMS-754807 的组合在抑制大多数 TNBC 细胞系的细胞增殖方面比单独使用任何一种药物更有效，并且一个重要的机制可能是抑制 SCFSkp2 和随后的细胞周期抑制剂 p27Kip1 的稳定. 这种联合治疗可能代表一种有效的靶向治疗，适用于 TNBC 的重要子集，应进一步评估。