In discovery of HDAC inhibitors with improved activity and selectivity, fluorine substitution was performed on our previously derived lead compound. The synthesized molecules N-(2-amino-4-fluorophenyl)-4-[bis-(2-chloroethyl)-amino]-benzamide (FNA) exhibited class I (HDAC1, 2, and 3) selectivity in the in vitro enzymatic assay and especially potent against HDAC3 activity (IC₅₀: 95.48 nM). The results of in vitro antiproliferative assay indicated that FNA exhibited solid tumor cell inhibitory activities with IC₅₀ value of 1.30 μM against HepG2 cells compared with SAHA (17.25 μM). Moreover, the in vivo xenograft model study revealed that FNA could inhibit tumor growth with tumor growth inhibition (TGI) of 48.89% compared with SAHA (TGI of 48.13%). Further HepG2 cell–based apoptosis and cell cycle studies showed that promotion of apoptosis and G2/M phase arrest make contributions to the antitumor activity of FNA. In addition, drug combination results showed that 0.5 μM of FNA could improve the anticancer activity of taxol and camptothecin. The present studies revealed the potential of FNA utilized as a high potent lead compound for further discovery of isoform selective HDAC inhibitors.

在发现具有改进的活性和选择性的HDAC抑制剂后，对我们先前衍生的铅化合物进行了氟取代。合成分子N-（2-氨基-4-氟苯基）-4- [bis-（2-氯乙基）-氨基]-苯甲酰胺（FNA）在I类（HDAC1、2和3）中具有选择性 体外酶促测定，尤其对HDAC3活性有效（IC ₅₀：95.48 nM）。结果体外抗增殖试验表明，与SAHA（17.25μM）相比，FNA对HepG2细胞表现出实体瘤细胞抑制活性，IC ₅₀值为1.30μM。而且，体内异种移植模型研究表明，与SAHA（TGI为48.13％）相比，FNA可以抑制肿瘤生长，其中TGI为48.89％。进一步的基于HepG2细胞的凋亡和细胞周期研究表明，促进凋亡和G2 / M期阻滞有助于FNA的抗肿瘤活性。此外，药物联合结果显示0.5μMFNA可以提高紫杉醇和喜树碱的抗癌活性。本研究揭示了FNA作为高效先导化合物用于进一步发现同工型选择性HDAC抑制剂的潜力。