Academy of Scientific & Innovative Research (AcSIR), CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu, 180001, India.
Cancer Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Jammu, 180001, India.
Breast Cancer Res Treat. 2019 Sep;177(2):307-323. doi: 10.1007/s10549-019-05301-0. Epub 2019 Jun 7.
More than 90% of the breast cancer deaths occur due to the metastasis of the cancer cells to secondary organ sites. Increased Glucose-regulated protein 78 (GRP78) expression is critical for epithelial-mesenchymal transition (EMT) and invasion in breast cancer resulting in poor patient survival outcomes. Therefore, there is an urgent need of potential inhibitors of GRP78 for the abrogation of invasion and metastasis in breast cancer.
We investigated the effect of IKM5 (2-(1-(1H-indol-3-yl)octyl)-3-hydroxy-6-(hydroxymethyl)-4H-pyran-4-one) (a novel Indolylkojyl methane analogue) on invasion abilities of human breast cancer cells employing invadopodia formation, Matrigel invasion assays, and mouse models for metastasis. The mechanism underlying the anti-invasive effect of IKM5 was examined through molecular docking, immunoblotting, immunocytochemistry, co-immunoprecipitation analysis, siRNA silencing, and sub-cellular fractionation studies.
Treatment with IKM5 at its sub-toxic concentration (200 nM) suppressed invasion and invadopodia formation, and growth factor-induced cell scattering of aggressive human breast cancer MDA-MB-231, MDA-MB-468, and MCF7 cells. IKM5 spontaneously binds to GRP78 (Ki = 1.35 µM) and downregulates its expression along with the EMT markers MMP-2, Twist1, and Vimentin. Furthermore, IKM5 amplified the expression and nuclear translocation of tumor suppressor Par-4 to control NF-kB-mediated pro-EMT activities. Interestingly, IKM5 disrupts the interaction between GRP78 and TIMP-1 by inhibiting GRP78 in a Par-4-dependent manner. Moreover, IKM5 inhibited tumor growth and lung metastasis at a safe dose of 30 mg/kg/body weight.
Our study warrants IKM5, a potential anticancer agent that can abrogate invasion and metastasis, suggesting its clinical development for the treatment of patients with advanced breast cancer.
超过 90%的乳腺癌死亡是由于癌细胞转移到次级器官部位。葡萄糖调节蛋白 78（GRP78）表达增加对于乳腺癌中的上皮间质转化（EMT）和侵袭至关重要，导致患者预后不良。因此，迫切需要潜在的 GRP78 抑制剂来阻断乳腺癌的侵袭和转移。
我们研究了 IKM5（2-（1-（1H-吲哚-3-基）辛基）-3-羟基-6-（羟甲基）-4H-吡喃-4-酮）（一种新型吲哚基壳聚糖类似物）对人乳腺癌细胞侵袭能力的影响，采用侵袭小窝形成、Matrigel 侵袭试验和转移的小鼠模型。通过分子对接、免疫印迹、免疫细胞化学、共免疫沉淀分析、siRNA 沉默和亚细胞分级研究，研究了 IKM5 抗侵袭作用的机制。
在亚毒性浓度（200 nM）下，IKM5 处理可抑制侵袭和侵袭小窝形成，以及侵袭性人乳腺癌 MDA-MB-231、MDA-MB-468 和 MCF7 细胞生长因子诱导的细胞散射。IKM5 可自发与 GRP78 结合（Ki=1.35 μM），并下调其表达以及 EMT 标志物 MMP-2、Twist1 和 Vimentin。此外，IKM5 扩增肿瘤抑制因子 Par-4 的表达并将其核易位，以控制 NF-kB 介导的促 EMT 活性。有趣的是，IKM5 通过依赖于 Par-4 的方式抑制 GRP78 来破坏 GRP78 与 TIMP-1 的相互作用。此外，IKM5 在安全剂量 30 mg/kg/体重下抑制肿瘤生长和肺转移。
我们的研究证明了 IKM5 是一种潜在的抗癌药物，可以阻断侵袭和转移，这表明其在治疗晚期乳腺癌患者方面具有临床开发潜力。
