Structure-based design and synthesis of KX-01 analogs as potent antitumor agents targeting the tubulin colchicine binding site

  • Eur J Med Chem. 2026 Aug 5:312:118849. doi: 10.1016/j.ejmech.2026.118849.
Chufeng Zhang  1 ,  Yilin Wang  1 ,  Chenke Gao  2 ,  Maoru Sun  1 ,  Minghai Tang  3 ,  Fang Wang  1 ,  Hongxiu Chen  1 ,  Shuai Zhang  1 ,  Li Liu  1 ,  Qingqing Li  1 ,  Xue Cui  3 ,  Xiuying Hu  1 ,  Zhuang Yang  4 ,  Jianhong Yang  5 ,  Yong Li  6
Affiliations
  • 1. Innovation Center of Nursing Research and Nursing Key Laboratory of Sichuan Province, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/West China School of Nursing, Sichuan University, Chengdu, Sichuan, 610041, China.
  • 2. State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, 610041, China.
  • 3. Laboratory of Natural and Targeted Small Molecule Drugs, Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.
  • 4. Laboratory of Natural and Targeted Small Molecule Drugs, Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China. Electronic address: [email protected].
  • 5. Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China. Electronic address: [email protected].
  • 6. Innovation Center of Nursing Research and Nursing Key Laboratory of Sichuan Province, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/West China School of Nursing, Sichuan University, Chengdu, Sichuan, 610041, China. Electronic address: [email protected].
PMID: 42001543 DOI: 10.1016/j.ejmech.2026.118849
Abstract

Our preliminary studies indicated that KX-01 inhibits tubulin polymerization in a reversible and concentration-dependent manner, resulting in dramatically low toxicity across various solid and liquid tumor types. However, KX-01 has not yet been approved as an Anticancer agent due to its insufficient efficacy, and research on its derivatives remains limited. To improve its antitumor activity and investigate the structure-activity relationships (SARs), sixty-seven KX-01 analogs were designed and synthesized based on the KX-01-tubulin cocrystal structure. Among them, compound 8h exhibited the most potent antiproliferative activity, with IC50 values of 3.5 ± 0.6, 2.4 ± 0.2, 15.7 ± 3.1, 22.1 ± 1.9, and 7.3 ± 1.1 nM against HCT116, HeLa, A2780S, A2780T, and HT29 cells, respectively, indicating its potential to overcome multidrug resistance. Replacing the endocyclic nitrogen atom in the pyridine ring of KX-01 with an exocyclic fluorine atom directly results in the loss of Src inhibitory activity. The cocrystal of 8h-tubulin complex revealed that it simultaneously occupies the colchicine site in β-tubulin and a cavity in α-tubulin. In the HT29 xenograft model, orally administered 8h (5 mg/kg, once daily) showed marginally superior in vivo antitumor efficacy than KX-01.

Keywords
Colchicine site; KX-01; Microtubule depolymerization.
Products