The Hsp90 inhibitor FW-04-806 suppresses Bcr/Abl-mediated growth of leukemia cells by inhibiting proliferation and inducing apoptosis / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the antitumor efficacy and mechanism of HSP90 inhibitor FW-04-806 against Bcr/Abl(+) leukemia K562 and HL60 cells and their mechanisms of action.</p><p><b>METHODS</b>MTT assay was used to assess the proliferation-inhibiting effect of FW-04-806. Cell cycle was analyzed with propidium iodide by flow cytometry. Cell apoptosis was determined using the FITC mV apoptosis detection kit. Western blot was applied to reveal the protein expression of related proliferative and apoptotic signaling pathways. The changes of mitochondrial membrane potential were detected by flow cytometry. Protein-protein interactions was shown by co-immunoprecipitation. The level of mRNA was assessed by real-time RT-PCR.</p><p><b>RESULTS</b>FW-04-806 obviously inhibited cell proliferation in the HL60, K562 and HL60/Bcr-Abl cell lines, with an IC50 of (30.89 ± 0.12) µmol/L, (9.76 ± 0.19) µmol/L and (8.03 ± 0.26) µmol/L, respectively (P<0.001). Compared with the vehicle group, the two increasing doses of FW-04-806 showed inhibition of tumor growth at a rate of (17.40 ± 0.34)% and (34.33 ± 5.00)%, respectively, in the K562 cell line groups (P=0.003), and (18.90 ± 1.45)% and (35.60 ± 3.55)% (P=0.001) in the HL60/Bcr-Abl cell line groups. FW-04-806 dissociated Hsp90/Cdc37 chaperon/co-chaperon complex, followed by degradation of the Hsp90 proteins through proteasome pathway without affecting mRNA expression. FW-04-806 induced apoptosis and led to G2/M arrest.</p><p><b>CONCLUSION</b>Our findings indicate that FW-04-806 displays potential antitumor effect by suppressing the proliferation and apoptosis in Bcr/Abl(+) leukemia cells in vivo.</p>

Efficacy and mechanism of FW-04-806 against HER2-positive gastric cancer cell lines / 中国药理学通报

Aim To investigate the efficacy and mech-anism of FW-04-806 against HER2-positive gastric cancer cell lines,and the combination effect of FW-04-806 with lapatinib. Methods MTT assay was used to assess cell proliferous inhibition of FW-04-806 . The in-hibitory effect of colony formation was tested by colony formation. The protein expression, apoptotic induction and cell cycle arrest were detected by flow cytometry. Co-immunoprecipitation was used to investigate protein-protein interactions. The expression change of proteins was showed by immunohistochemistry. Western blot was applied to reveal the protein expression of related pro-liferous and apoptotic signaling pathway. The tumor growth inhibition was evaluated in tumor xenograft model. Results FW-04-806 obviously inhibited cell proliferation and colony formation in HER2 positive gastric cancer cell lines NCI-N87, OE19, with IC50 of (24. 17 ± 0. 02 ) , ( 29. 61 ± 0. 03 ) μmol · L-1 , re-spectively;FW-04-806 induced G2-M arrest and apop-tosis in a dose-dependent manner;200 mg · kg-1 of FW-04-806 showed tumor growth inhibition of 48. 0%( P < 0. 01 ) . In addition, FW-04-806 dissociated Hsp90/CDC37 complex, followed by degradation of HER2 and Akt,inhibiting the phosporylation of HER2, Akt and ERK, and increasing expression of apoptotic proteins,such as cleaved caspase-3 and cleaved parp. Furthermore,the combination of FW-04-806 with lapa-tinib in vitro was synergistic in NCI-N87 , which en-hanced the inhibition of cell proliferation and increased apoptotic rates. Conclusions FW-04-806 shows po-tent efficacy against HER2-positive gastric cancer cell lines in vitro and in vivo;FW-04-806 is synergistic with lapatinib.