ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effects of arsenic trioxide (AsO) on K562 cell proliferation by regulating cell cycle protein D1 and cyclin-dependent kinase inhibitor p27kip1.</p><p><b>METHODS</b>MTT was used to detect the effect of AsOon K562 cell proliferation, so as to screen out the appropriate drug concentration. Furthermore, the K562 cell apoptosis was observed by microscopy. The expression of CyclinD1 and p27kip1 in K562 cells treated with AsOwas analyzed by reverse transcription-polymerase chain reaction(RT-PCR), immunohistochemistry and Western blot.</p><p><b>RESULTS</b>AsOcould inhibit the proliferation of K562 cells in a dose- and time- dependent manner (r= 0.967). And the apoptosis cell number in AsOgroup was significantly higher than that in the control group(P<0.05). AsOcould markedly inhibit the expression of CyclinD1 in K562 cells(P<0.05), but the expression of P27kip1 was not significantly changed after AsOtreatment.</p><p><b>CONCLUSIONS</b>AsOcan induce K562 cell apoptosis and inhibit K562 cell proliferation by regulating the expression of CyclinD1.</p>
ABSTRACT
To analyze the protein composition of Brucea javanica seeds and evaluate the cytotoxicity of its gulbulin hydrolysates. Four protein fractions of albumin, gulbulin, prolamin and glutelin were sequentially extracted and then quantified by Kjeldahl method. Different kinds of proteases were applied to hydrolyze B.javanica gulbulin, and MTT assay was used to evaluate the cytotoxicity of low molecular weight hydrolysates (≤3 kDa) on human breast cancer MCF-7 cell. The results showed that： the total protein content of B.javanica seeds was 17.47%, albumin, gulbulin, coxin, glutelin and residue protein accounted for 15.01%, 8.11%, 2.47%, 44.92% and 23.62% of the total protein content, respectively. The hydrolysates (≤3 kDa) of B.javanica globulin produced by pepsin showed significant growth inhibitory activity on MCF-7 cells, and the IC₅₀ value was（6.52±0.01） mg•L⁻¹ after 72 h of incubation. Protein was abundant in B.javanica seeds, and its peptides demonstrated specific cytotoxicity on MCF-7 cell line in vitro, suggesting antitumor active ingredient can be further generated from B.javanica seeds.