新生霉素钠是新生霉素的钠盐,其抗菌谱与青霉素相似,主要用于耐药性金黄色葡萄球菌引起的感染,如肺炎、败血症等。尽管对严重感染疗效较差,但易引起细菌耐药性,因此宜与其他抗菌药物配伍使用。
新生霉素是从雪白链霉菌(Streptomyces niveus)的发酵中获得的一种抗生素,对抗青霉素耐药的葡萄球菌和某些变形杆菌有效。其抗菌作用在于抑制DNA复制,并通过干扰DNA解旋酶(拓扑异构酶)的作用来实现。
生物活性Novobiocin钠盐(Albamycin、Cathomycin)是一种高效的细菌DNA旋转酶抑制剂,同时也是一种人体有机阴离子转运体,能够作用于hOAT1、hOAT3和hOAT4,其Ki值分别为14.87±0.40μM、4.77±1.12μM 和 90.50±7.50μM。
靶点Target | Value |
---|---|
Topoisomerase II | |
Topoisomerase IV |
Novobiocin与Hsp90结合,改变了分子伴侣对geldanamycin和radicicol的亲和力,进而影响了依赖于Hsp90的关键调节激酶,包括V形Src、RAF-1和P185(ErbB2)在体内外水平上的表达。此外,Novobiocin还干扰共伴侣Hsc70和p23对Hsp90的结合,并以浓度依赖性方式特异性地抑制血红素调节eIF2α激酶(HRI)的成熟。
Novobiocin通过诱导Hsp90与CDC37从未成熟HRI解离,而Hsp90共分子伴侣P23、FKBP52和蛋白磷酸酶5仍然与未成熟HRI结合。这种作用导致了细胞形态和生化变化,进而引发细胞凋亡。
此外,Novobiocin作为HSP90抑制剂,能够降低SMYD3的表达,并剂量依赖性地抑制MDA-MB-231人乳腺癌细胞的增殖和迁移。它还能够通过下调SMYD3抑制乳腺癌细胞的迁移。
Novobiocin作为一种氨基酮类抗生素,干扰了热休克蛋白90(Hsp90)和缺氧诱导因子依赖基因表达的过程,从而损害了细胞的存活能力。在体外实验中,500 μM浓度的Novobiocin显著增加了胞内钙离子浓度、减少了前向散射、增强了膜联蛋白-V结合以及促进了ceramide的形成。
同时,它还能刺激红细胞死亡,这可能与细胞外Ca²⁺的进入和ceramide的产生有关。
Polymerase theta (Polθ) acts in DNA replication and repair, and its inhibition is synthetic lethal in BRCA1 and BRCA2-deficient tumor cells. Novobiocin (NVB) is a first-in-class inhibitor of the Polθ ATPase activity, and it is currently being tested in clinical trials as an anti-cancer drug. Here, we investigated the molecular mechanism of NVB-mediated Polθ inhibition. Using hydrogen deuterium exchange-mass spectrometry (HX-MS), biophysical, biochemical, computational and cellular assays, we found NVB is a non-competitive inhibitor of ATP hydrolysis. NVB sugar group deletion resulted in decreased potency and reduced HX-MS interactions, supporting a specific NVB binding orientation. Collective results revealed that NVB binds to an allosteric site to block DNA binding, both in vitro and in cells. Comparisons of The Cancer Genome Atlas (TCGA) tumors and matched controls implied that POLQ upregulation in tumors stems from its role in replication stress responses to increased cell proliferation: this can now be tested in fifteen tumor types by NVB blocking ssDNA-stimulation of ATPase activity, required for Polθ function at replication forks and DNA damage sites. Structural and functional insights provided in this study suggest a path for developing NVB derivatives with improved potency for Polθ inhibition by targeting ssDNA binding with entropically constrained small molecules.