666-15 is a selective cyclic AMP response element binding protein (CREB) inhibitor with an IC50 value of 0.081±0.04μM[1]. 666-15 also inhibits the expression of endogenous CREB target genes, namely the transcription level of nuclear receptor-related protein 1 (Nurr1/NR4A2)[1]. CREB is a nuclear transcription factor that can be activated by a variety of extracellular signals (including growth factors and hormones)[2]. 666-15 blocks the neuroprotective effect of necrotizing inhibitor necrotizing inhibitor necrotizing inhibitor 1 (nec-1), which is a specific and effective inhibitor of necroptosis[3].
In vitro, treatment of newborn rat cardiomyocytes (NRCMs) with 666-15 (1µM) for 2h effectively inhibited phenylephrine-induced CREB phosphorylation, but had no significant effect on p38 phosphorylation[4]. Treatment of aged guinea pig chondrocytes with 666-15 (0-500nM) significantly reduced the protein level of p-CREB1 and increased cell viability[5]. 666-15 (0-10µM) treatment of HEK293T cells transfected with different transcription factors for 5-7h showed little or no inhibition of Gal4-MLL, Gal4-c-Myb, Gal4-TEAD4/YAP1, and serum response factor (SRF)-mediated gene transcription[6].
In vivo, 666-15 (10mg/kg) was intraperitoneally injected into mice transplanted with triple-negative breast cancer (TNBC) cells and inhibited breast cancer growth. Combination with docetaxel (DOC) showed better effects and had no significant effect on mouse body weight[7].
References:
[1] Xie F, Li B X, Kassenbrock A, et al. Identification of a potent inhibitor of CREB-mediated gene transcription with efficacious in vivo anticancer activity[J]. Journal of medicinal chemistry, 2015, 58(12): 5075-5087.
[2] Shaywitz A J, Greenberg M E. CREB: a stimulus-induced transcription factor activated by a diverse array of extracellular signals[J]. Annual review of biochemistry, 1999, 68(1): 821-861.
[3] Yang C, Li T, Xue H, et al. Inhibition of necroptosis rescues SAH-induced synaptic impairments in hippocampus via CREB-BDNF pathway[J]. Frontiers in neuroscience, 2019, 12: 990.
[4] Zhang B, Zhang P, Tan Y, et al. C1q-TNF-related protein-3 attenuates pressure overload-induced cardiac hypertrophy by suppressing the p38/CREB pathway and p38-induced ER stress[J]. Cell death & disease, 2019, 10(7): 520.
[5] Wang Y, Wu Z, Yan G, et al. The CREB1 inhibitor 666-15 maintains cartilage homeostasis and mitigates osteoarthritis progression[J]. Bone & Joint Research, 2024, 13(1): 4-18.
[6] Li B X, Gardner R, Xue C, et al. Systemic inhibition of CREB is well-tolerated in vivo[J]. Scientific Reports, 2016, 6(1): 34513.
[7] Qin Y, Chen W, Jiang G, et al. Interfering MSN-NONO complex-activated CREB signaling serves as a therapeutic strategy for triple-negative breast cancer. Sci Adv 6: eaaw9960[J]. 2020.
666-15是一种选择性环磷酸腺苷反应元件结合蛋白（CREB）抑制剂，IC50值为0.081±0.04μM[1]。666-15还抑制内源性CREB靶基因表达，即核受体相关蛋白1（Nurr1/NR4A2）的转录水平[1]。CREB是一种核转录因子，可被多种细胞外信号（包括生长因子和激素）激活[2]。666-15会阻碍坏死抑制素-1（nec-1）的神经保护作用，nec-1是一种特异性、有效的坏死性凋亡抑制剂[3]。
在体外，666-15（1µM）处理新生大鼠心肌细胞（NRCMS）2h，有效抑制了苯肾上腺素诱导的CREB磷酸化，但是对p38磷酸化没有显著影响[4]。666-15（0-500nM）处理老年豚鼠软骨细胞，显著降低了p-CREB1的蛋白水平，提高了细胞活力[5]。666-15（0-10µM）处理用不同转录因子转染的HEK293T 细胞5-7h，对Gal4-MLL、Gal4-c-Myb、Gal4-TEAD4/YAP1、和血清反应因子（SRF）介导的基因转录表现出很少或没有抑制[6]。
在体内，666-15（10mg/kg）通过腹腔注射治疗移植了三阴性乳腺癌（TNBC）细胞的小鼠，抑制了乳腺癌的生长，与多西他赛（DOC）联合使用显示出更好的效果，且对小鼠体重没有明显影响[7]。