基于咪唑并噻唑的 BRAF V600E 强效抑制剂克服了 PLX4032 耐药性黑色素瘤中 RAF 二聚化的获得性耐药抑制。

Potent Imidazothiazole-based Inhibitor of BRAF V600E Overcomes Acquired Resistance Inhibition of RAF Dimerization in PLX4032-resistant Melanoma.

机构信息

College of Pharmacy, Chosun University, Gwangju, Republic of Korea.

Center for Biomaterials, Korea Institute of Science and Technology, Seoul, Republic of Korea.

出版信息

Anticancer Res. 2022 Jun;42(6):2911-2921. doi: 10.21873/anticanres.15773.

DOI:10.21873/anticanres.15773

PMID:35641256

Abstract

BACKGROUND/AIM: The B-raf proto-oncogene, serine/threonine kinase (BRAF) V600E mutation is frequent in patients with advanced melanoma. PLX4032, an inhibitor of BRAFV600E kinase, is effective for the treatment of melanoma in BRAF V600E-positive patients; however, resistance eventually develops due to paradoxical activation of the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinases (ERK) pathway resulting from RAF dimerization. In this study, we investigated the inhibitory effects of a novel imidazothiazole-based compound, KS28, on RAF dimerization and resistance to PLX4032 in melanoma.

MATERIALS AND METHODS

The effects of KS28 were examined by immunoblotting, cell viability, terminal deoxynucleotidyl transferase dUTP nick-end labeling, reporter-gene, and soft-agar assays.

RESULTS

KS28 treatment inhibited RAF dimerization in PLX4032-resistant A375 (A375R) cells, leading to suppression of the MEK/ERK pathway. In addition, KS28 reduced activator protein 1 transactivation in A375R cells, reduced cell viability, and increased DNA fragmentation. Moreover, treatment with KS28 suppressed anchorage-independent growth of A375R cells. Similarly, in an orthotopic tumor xenograft model, KS28 treatment suppressed the growth of tumors formed by A375R cells in BALB/c mice.

CONCLUSION

KS28 plays a vital role in overcoming PLX4032 resistance in melanoma by down-regulating the MEK/ERK pathway.

摘要

背景/目的：B-raf 原癌基因，丝氨酸/苏氨酸激酶（BRAF）V600E 突变在晚期黑色素瘤患者中频繁发生。PLX4032，一种 BRAFV600E 激酶的抑制剂，对 BRAF V600E 阳性的黑色素瘤患者的治疗有效；然而，由于 RAF 二聚化导致丝裂原活化蛋白激酶激酶（MEK）/细胞外信号调节激酶（ERK）途径的反常激活，最终会产生耐药性。在这项研究中，我们研究了一种新型咪唑并噻唑基化合物 KS28 对黑色素瘤中 RAF 二聚化和对 PLX4032 耐药性的抑制作用。

材料和方法

通过免疫印迹、细胞活力、末端脱氧核苷酸转移酶 dUTP 缺口末端标记、报告基因和软琼脂测定来检查 KS28 的作用。

结果

KS28 处理抑制了 PLX4032 耐药的 A375（A375R）细胞中的 RAF 二聚化，从而抑制了 MEK/ERK 途径。此外，KS28 降低了 A375R 细胞中的激活蛋白 1 反式激活作用，降低了细胞活力并增加了 DNA 片段化。此外，KS28 抑制了 A375R 细胞的锚定非依赖性生长。同样，在原位肿瘤异种移植模型中，KS28 处理抑制了 BALB/c 小鼠中 A375R 细胞形成的肿瘤的生长。