Tirbanibulin (KX2-391) is a highly selective Src kinase inhibitor that has demonstrated efficacy in pre-Clinicalal animal models of colon, pancreatic, prostate and breast cancer. It is a substrate-targeted kinase inhibitor. KX2-391, belongs to an emerging new family of targeted cancer treatments called protein kinase inhibitors.

Src (HuH-7):9 nM(GI50), Src (HepG2):60 nM(GI50), Src (Hep3B):26 nM(GI50), Src (PLC/PRF/5):13 nM(GI50)

Tirbanibulin是一种针对Src底物口袋的Src抑制剂。在四种肝细胞癌（HCC）细胞系—Huh7（GI 50 = 9 nM）、PLC/PRF/5（GI 50 = 13 nM）、Hep3B（GI 50 = 26 nM）和HepG2（GI 50 = 60 nM）—中，Tirbanibulin展示了陡峭的剂量-响应曲线。[1] Tirbanibulin还被发现能抑制某些对当前市售药物具有抗性的白血病细胞，如带有T3151突变的慢性白血病细胞。在NIH3T3/c-Src527F和SYF/c-Src527F细胞的工程化Src驱动细胞增长评估中，Tirbanibulin分别显示出23 nM和39 nM的GI50。[2]

在临床前的癌症动物模型中，口服KX2-391能够抑制原发性肿瘤生长并抑制转移。[2]

Liver cell lines including Huh7, PLC/PRF/5, Hep3B, and HepG2 (NutriCyte, Buffalo, NY) are routinely cultured and maintained in basal medium containing 2% fetal bovine serum (FBS) at 37 °C and 5% CO2. Cells are seeded at 4.0 × 103/190 μL and 8.0 × 103/190 μL per well of 96-well plate in basal medium containing 1.5% FBS. These are cultured overnight at 37 °C and 5% CO2 prior to the addition of KX2-391, at concentrations ranging from 6,564 to 0.012 nM in triplicates. Treated cells are incubated for 3 days. Ten microliters of 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide (MTT) solution (5 mg/mL) is then added to each well on day 3 and cells incubated for 4 hours. The formazan product is dissolved with 10% SDS in dilute HCl. Optical density at 570 nm is measured by using BioTek Synergy HT multiplatform microplate reader. For comparison of activity and potency, parallel experiments are performed using KX2-391. Growth inhibition curves, 50% inhibition concentration (GI50), and 80% inhibition concentration (GI80) are determined using GraphPad Prism 5 statistical software. Data are normalized to represent percentage of maximum response as well as reported in optical density at wavelength of 570 nm (OD570) signal format.</ (Only for Reference)