Click-chemistry mediated synthesis of podophyllotoxin triazole ether derivatives: Inhibiting human CRC tumor growth via dual targeting of AKT1 and tubulin.

Podophyllotoxin (PPT) is an aryltetralin lignan with tubulin-inhibiting and potential anti-colorectal cancer (CRC) properties. However, its cytotoxicity and tendency to induce drug resistance limit its clinical utility. The AKT signaling pathway is pivotal in tumor cell proliferation, metabolic reprogramming, and drug resistance. Inhibiting AKT activity can enhance tumor cell sensitivity to microtubule-targeting drugs. In this study, a molecular library of PPT derivatives (10,800 compounds) was generated based on the PPT scaffold using structure-activity relationship (SAR) analysis. Screening identified 11 AKT1/tubulin dual-targeting PPT-1,2,3-triazole ether derivatives with potential anti-colorectal cancer activity. The most potent compound, 2b (IC50 = 0.77 ± 0.05 μmol/L), demonstrated significant antiproliferative effects on HCT-116 cells, surpassing PPT (IC50 = 3.83 ± 0.25 μmol/L) and gefitinib (IC50 = 42.87 ± 3.39 μmol/L) by 4.9-fold and 55.7-fold, respectively. Compound 2b inhibited HCT-116 cell colony formation, arrested the cell cycle at G2/M phase, suppressed cell migration, and induced apoptosis. Molecular docking and dynamics simulations revealed that 2b could dual-target AKT1 and tubulin with higher binding stability than PPT. Laser confocal microscopy demonstrated its efficacy in promoting tubulin depolymerization. Mechanistic investigations showed that 2b downregulated p-AKT expression, inhibiting AKT signaling pathway activation. Notably, compound 2b exhibited good water solubility and significantly inhibited tumor growth in mouse xenograft models. In conclusion, compound 2b, as an AKT1/tubulin dual inhibitor, has great potential in CRC treatment and is worthy of further research.