Bufalin induces apoptosis in osteosarcoma U-2OS and U-2OS methotrexate 300-resistant cell lines in vitro / 中华肿瘤杂志

ABSTRACT

<p><b>OBJECTIVE</b>To study the growth inhibition and apoptosis induction effects of bufalin on human osteosarcoma cell lines in vitro.</p><p><b>METHODS</b>U-2OS and U-2OS/methotrexate (MTX) 300-resistant cell lines were treated with bufalin. Cell viability was assessed by MTT assay. Cell-cycle status, apoptosis-inducing effects, and the expression of apoptosis-related proteins were evaluated by flow cytometry, fluorescent staining, DNA fragmentation assay, and Western blotting.</p><p><b>RESULTS</b>Bufalin inhibited cell growth in both U-2OS and U-2OS/MTX300 cells. The IC(50) values of bufalin for U-2OS and U-2OS/MTX300 cells were (8.49 ± 2.1) ng/ml and (10.19 ± 1.7) ng/ml, respectively. The induction of G(2)/M cell-cycle arrest was also seen in the bufalin-treated cells. The bufalin-induced apoptosis was confirmed by increased expression of tumor suppressor protein p53, bax and decreased expression of bcl-2.</p><p><b>CONCLUSION</b>Bufalin inhibits the growth of and induces apoptosis in both MTX-sensitive and MTX-resistant human osteosarcoma U-2OS cell lines. The apoptosis-inducing effect of bufalin is not influenced by the presence of high levels of DHFR.</p>