[Inhibitive effect and mechanism of monoclonal antibody targeted SEA on human bladder cancer cell line BIU-87].
OBJECTIVE
To investigate the in vitro inhibitive effect and apoptotic mechanism of BDI-1 monoclonal antibody targeted SEA on human bladder cancer cell line BIU-87.


METHODS
Human peripheral blood mononuclear cells (PBMC) and human bladder cancer cell line BIU-87 were used as effector and target cells respectively in three experimental groups, control group, SEA group and monoclonal antibody targeted SEA group, treated with different concentrations of SEA and targeted SEA respectively in the latter two. The inhibition rates of target cells were measured by cell counting kit-8 (CCK-8) assay. Apoptosis was determined by fluorescent Hocehst 33258 staining and flow cytometry (FCM). The expression of Bax, Bcl-2 proteins and cytokine concentration of co-culture supernatants were detected by Western blot and ELISA respectively.


RESULTS
Compared with those of control group (from 5.8% +/- 3.0% to 16.5% +/- 4.0%) and SEA group (from 20.7% +/- 2.1% to 68.6% +/- 4.0%), the inhibition rates in targeted SEA group increased significantly (from 31.2% +/- 2.6% to 88.7% +/- 3.0%, P < 0.05). Characteristic changes of apoptosis were observed in both experimental treatment groups, especially in targeted SEA group. FCM also showed more prominent apoptosis induced in targeted SEA group (from 14.6% +/- 0.7% to 66.5% +/- 3.3%), significantly higher than those of control group (from 4.6% +/- 0.7% to 6.5% +/- 0.3%) and SEA group (from 9.1% +/- 0.6% to 29.9% +/- 1.3%, P < 0.05). In addition, Western blot analysis indicated that the ratio of Bax/Bcl-2 significantly increased to (3.29 +/- 0.34) by targeted SEA treatment at an extremely low concentration, significantly higher than those of SEA group (1.21 +/- 0.05) and control group (0.45 +/- 0.15) (P < 0.05). While at the same time ELISA assay showed no significant difference of IL-2, TNF-alpha, IFN-gamma concentrations between SEA and targeted SEA groups.


CONCLUSIONS
Monoclonal antibody targeted SEA significantly increases the inhibitive effect of BIU-87 cell line possibly through the up-regulation of Bax/Bcl-2 ratio to promote the cellular apoptosis.
Gong
Zhen
Z
School of Clinical Medicine, Southeast University, Nanjing 210009, China.
Zhang
Pei-ying
PY
Han
Cong-hui
CH
Hao
Lin
L
Yang
Jian-jun
JJ
Wang
Tao
T
Tang
Wen-hao
WH
D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology*; D000942:Antigens, Bacterial / Q000276:immunology*; D017209:Apoptosis; D045744:Cell Line, Tumor; D004768:Enterotoxins / Q000276:immunology*; D006801:Humans; D013211:Staphylococcus aureus / Q000276:immunology*; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy*
D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D004768:Enterotoxins