Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand.
Int J Oncol. 2012 Nov;41(5):1723-32. doi: 10.3892/ijo.2012.1625. Epub 2012 Sep 11.
There is a need for the development of new safe and efficacious drug therapies for the treatment of estrogen receptor (ER)‑negative breast cancers. 1-Methyl-3,5-bis[(E)-4-pyridyl)methylidene]-4-piperidone (RL66) is a second generation curcumin analog that exhibits potent cytotoxicity towards a variety of ER-negative breast cancer cells. Therefore, we have further examined the mechanism of this novel drug in in vitro and in vivo models of ER-negative breast cancer. The mechanistic studies demonstrated that RL66 (2 µM) induced cell cycle arrest in the G2/M phase of the cell cycle. Moreover, RL66 (2 µM) caused 40% of SKBr3 cells to undergo apoptosis after 48 h and this effect was time-dependent. This correlated with an increase in cleaved caspase-3 as shown by western blot analysis. RL66 (2 µM) also decreased HER2/neu phosphorylation and increased p27 in SKBr3 cells, while in MDA-MB-231 and MDA-MB-468 cells RL66 (2 µM) significantly decreased Akt phosphorylation and transiently increased the stress kinases JNK1/2 and MAPK p38. In addition, RL66 exhibited anti-angiogenic potential in vitro as it inhibited HUVEC cell migration 46% and the ability of these cells to form tube‑like networks. RL66 (8.5 mg/kg) suppressed the growth of MDA-MB-468 xenograft tumors by 48% compared to vehicle control following 10 weeks of daily oral administration. Microvessel density in the tumors from treated mice was also decreased 57% compared to control. Thus our findings demonstrate that RL66 has potent proapoptotic and anti-angiogenic properties in vivo and in vitro and has the potential to be further developed as a drug for the treatment of ER‑negative breast cancer.
需要开发新的安全有效的药物疗法来治疗雌激素受体（ER）阴性乳腺癌。1-甲基-3,5-双[(E)-4-吡啶基)亚甲基]-4-哌啶酮（RL66）是一种第二代姜黄素类似物，对多种 ER 阴性乳腺癌细胞具有强烈的细胞毒性。因此，我们进一步研究了这种新型药物在 ER 阴性乳腺癌的体外和体内模型中的作用机制。机制研究表明，RL66（2 μM）诱导细胞周期停滞在细胞周期的 G2/M 期。此外，RL66（2 μM）在 48 小时后使 40%的 SKBr3 细胞发生凋亡，且这种作用呈时间依赖性。Western blot 分析显示，这与 cleaved caspase-3 的增加有关。RL66（2 μM）还降低了 SKBr3 细胞中 HER2/neu 的磷酸化并增加了 p27，而在 MDA-MB-231 和 MDA-MB-468 细胞中 RL66（2 μM）显著降低了 Akt 的磷酸化并短暂增加了应激激酶 JNK1/2 和 MAPK p38。此外，RL66 在体外表现出抗血管生成潜力，因为它抑制 HUVEC 细胞迁移 46%并抑制这些细胞形成管状网络的能力。与 vehicle 对照组相比，RL66（8.5 mg/kg）在 10 周的每日口服给药后抑制 MDA-MB-468 异种移植肿瘤的生长 48%。与对照组相比，治疗小鼠肿瘤中的微血管密度也降低了 57%。因此，我们的研究结果表明，RL66 在体内和体外具有强大的促凋亡和抗血管生成特性，有潜力进一步开发为治疗 ER 阴性乳腺癌的药物。
