RESUMEN
OBJECTIVE To evaluate the anti-tumor activities of WX-127-07,a new microtubule-tar-geting agent invitroand probe its molecular mechanism. METHODS The well-known microtubule-targe-ting anti-tumor drugs taxol,vincristine and anti-gout drug colchicine were used as positive controls. The anti-proliferation activity was examined in five different cell lines after treatment with WX-127-07(0.3 -300 nmol·L-1 )for 72 h by SRB assay. The cell cycle arrest profile was assayed by flow cytometry. The multiparameters of cytotoxicity,cell morphology,apoptosis and different signaling pathways related to tumorigenesis and inflammation were analyzed using the high content analysis platform. Tubulin tryptic digestion and competition inhibition assay for colchicine or vinblastine site were used to confirm the bind-ing site in microtubules at a molecular level. RESULTS All the tested compounds obviously inhibited the growth of A549,HepG2,HeLa,HLF and HUVEC cells. The lC50 values of WX-127-07 were 4.47±0.05, 5.18±0.08,4.90±0.19,4.10±0.16 and(5.04±0.08)nmol·L-1 respectively,lower than those of colchicine〔the lC50 values were 21. 17 ± 1. 22,14. 19 ± 0. 53,43. 80 ± 1. 64,145. 89 ± 10. 97 and( 27. 67 ± 1.79)nmol·L-1 ,respectively〕and those of vincristine〔the lC50 values were 16.51±0.36,16.76±0.33, 27.80±2.75,43.80±1.48 and(9.15±0.78)nmol·L-1 ,respectively〕,but were similar to or lower than those of taxol〔the lC50 values were 10. 68 ± 0. 61,12. 86 ± 0. 25,4. 81 ± 0. 61,102. 07 ± 15. 17 and( 3. 04 ± 0.12)nmol·L-1 ,respectively〕. High content multi-parameter analysis revealed that WX-127-07 induced a concentration-dependent microtubular depolymerization(P=0.0075)with the same pattern as colchicine and vincristine,but at a lower concentration. Both WX-127-07 and positive drugs could induce cell cycle arrest in A549 cells,increase nuclear membrane permeability and early signs of apoptosis in HepG2 cells,but neither cancer related pathways nor inflammation related pathways were affected. Microtubular competition inhibition assay showed that WX-127-07 inhibited the binding of colchicine with tubulin(P =0.0259). Tryptic digestion of tubulin-WX-127-07 premixture showed a similar electrophoretic band to that of tubulin-colchicine premixture. CONCLUSION WX-127-07 is a novel microtubule-depolymerizing agent with anti-proliferation activity and acting on the colchicine binding site.