[Inhibitory effect of 4-chlorobenzoyl berbamine on imatinib-resistant K562 cells in vitro and in vivo].
OBJECTIVE
To observe the inhibitory effect of 4-chlorobenzoyl berbamine (BBD9) on imatinib-resistant cell line K562 (K562/IR) in vitro and in vivo and explore the mechanisms.


METHODS
The IC50 of BBD9 and berbamine (BBM) was determined by MTT assay. The expressions of p210(Bcr-Abl), IKKa, cytoplasmic and nuclear NF-κBp65 were determined using Western blotting in K562/IR cells following a 48-h exposure to 0.5 µg/ml BBD9 or 8 µg/ml BBM. Flow cytometry was used to analyze the cell viability, apoptosis and necrosis; Western blotting was employed to determine the expressions of PARP, caspase-3, caspase-9 and LC3II in K562/IR cells exposed to different concentrations of BBD9 for 48 h. In nude mouse models bearing K562/IR cell xenograft, the tumor weight, tumor regression, and body weight changes of the mice were measured after treatments with 15 mg/kg and 30 mg/kg BBD9 and 100 mg/kg imatinib.


RESULTS
The IC50 of BBD9 and BBM was 0.73 µg/ml and 5.43 µg/ml, respectively. In K562/IR cell cultures, the expressions of p210(Bcr-Abl), IKKa and nuclear NF-κB p65 were all decreased following BBD9 and BBM treatments, but BBD9 produced more potent effect; cytoplasmic NF-κB p65 showed no obvious changes after the treatments. The cell apoptosis and necrosis increased with the concentrations of BBD9, which also dose-dependently increased the levels of cleaved caspase-3, csapase-9, PARP, and LC3II expression. In the tumor-bearing mouse model, BBD9 showed stronger effects than imatinib in reducing the tumor weight, promoting tumor regression, and increasing the body weight.


CONCLUSIONS
BBD9 can effectively inhibit the growth of K562/IR cells in vitro and in vivo by activating cell apoptosis, necrosis and autophage pathways, down-regulating expressions of p210(Bcr-Abl) and IKKa and suppressing the cytoplasm-to- nucleus translocation of NF-κBp65.
Department of Hematology, Zhejiang University, Hangzhou, China. michaelzyf@163.com
Yun-feng
YF
Zhang
Gen-bo
GB
Xu
Yi-chao
YC
Gan
Xiao-hua
XH
Xu
Rong-zhen
RZ
Xu
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001549:Benzamides; D044182:Benzylisoquinolines / Q000494:pharmacology* / Q000627:therapeutic use; D019008:Drug Resistance, Neoplasm; D005260:Female; D016044:Fusion Proteins, bcr-abl / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism; D000068877:Imatinib Mesylate; D020014:K562 Cells; D008114:Liver Neoplasms, Experimental / Q000188:drug therapy* / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D010879:Piperazines / Q000494:pharmacology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011743:Pyrimidines / Q000494:pharmacology*; D051996:Transcription Factor RelA / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
C548958:4-chlorobenzoylberbamine; D000970:Antineoplastic Agents; D001549:Benzamides; D044182:Benzylisoquinolines; D010879:Piperazines; D011743:Pyrimidines; D051996:Transcription Factor RelA; D000068877:Imatinib Mesylate; D011505:Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl; D051550:I-kappa B Kinase