Dimethyl Fumarate Inhibits the Nuclear Factor B Pathway in Breast Cancer Cells by Covalent Modification of p65 Protein
Dimethyl Fumarate Inhibits the Nuclear Factor B Pathway in Breast Cancer Cells by Covalent Modification of p65 Protein
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DOI：
10.1074/jbc.m115.679704
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发表时间：
2016-02-12
影响因子：
4.8
通讯作者：
Frasor, Jonna
中科院分区：
文献类型：
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作者：
Kastrati, Irida;Siklos, Marton I.;Frasor, Jonna
在乳腺肿瘤中，核因子B （NFB）途径的激活促进了侵袭性疾病的生存、迁移、侵袭、血管生成、干细胞样特性和对治疗表型的抵抗，而治疗选择仍然有限。在乳腺癌治疗中加入抗炎/抗nfb药物将是有益的，但没有这种药物被批准作为单一疗法或辅助疗法。为了满足这一需求，我们研究了富马酸二甲酯（DMF），一种临床用于多发性硬化症的抗炎药物，是否可以抑制NFB途径。我们发现DMF在多种乳腺癌细胞系中有效阻断NFB活性，并消除NFB依赖性乳腺球形成，表明DMF具有抗癌干细胞特性。此外，DMF抑制细胞增殖并显著损害异种移植物肿瘤的生长。在机制上，DMF阻止p65核易位并减弱其DNA结合活性，但对NFB途径中的上游蛋白没有影响。琥珀酸二甲酯是DMF的无活性类似物，缺乏富马酸的亲电双键，不能抑制NFB的活性。此外，细胞渗透性巯基n -乙酰半胱氨酸逆转DMF对NFB途径的抑制，支持亲电试剂DMF通过共价修饰起作用的观点。为了确定DMF是否直接与p65相互作用，我们合成并使用了一种新的DMF化学探针，结合炔官能，发现DMF共价修饰p65，半胱氨酸38是DMF活性所必需的。这些结果表明DMF是一种具有抗肿瘤活性的NFB抑制剂，可能在治疗侵袭性乳腺癌中增加治疗价值。
In breast tumors, activation of the nuclear factor B (NFB) pathway promotes survival, migration, invasion, angiogenesis, stem cell-like properties, and resistance to therapyall phenotypes of aggressive disease where therapy options remain limited. Adding an anti-inflammatory/anti-NFB agent to breast cancer treatment would be beneficial, but no such drug is approved as either a monotherapy or adjuvant therapy. To address this need, we examined whether dimethyl fumarate (DMF), an anti-inflammatory drug already in clinical use for multiple sclerosis, can inhibit the NFB pathway. We found that DMF effectively blocks NFB activity in multiple breast cancer cell lines and abrogates NFB-dependent mammosphere formation, indicating that DMF has anti-cancer stem cell properties. In addition, DMF inhibits cell proliferation and significantly impairs xenograft tumor growth. Mechanistically, DMF prevents p65 nuclear translocation and attenuates its DNA binding activity but has no effect on upstream proteins in the NFB pathway. Dimethyl succinate, the inactive analog of DMF that lacks the electrophilic double bond of fumarate, is unable to inhibit NFB activity. Also, the cell-permeable thiol N-acetyl l-cysteine, reverses DMF inhibition of the NFB pathway, supporting the notion that the electrophile, DMF, acts via covalent modification. To determine whether DMF interacts directly with p65, we synthesized and used a novel chemical probe of DMF by incorporating an alkyne functionality and found that DMF covalently modifies p65, with cysteine 38 being essential for the activity of DMF. These results establish DMF as an NFB inhibitor with anti-tumor activity that may add therapeutic value in the treatment of aggressive breast cancers.