Small interfering RNA of cyclooxygenase-2 induces growth inhibition and apoptosis independently of Bcl-2 in human myeloma RPMI8226 cells.
OBJECTIVE
To investigate the effects of small interfering RNA of cyclooxygenase-2 (COX-2) on the proliferation and apoptosis of human multiple myeloma RPMI8226 cells and its relation with the Bcl-2 family in vitro.


METHODS
Transcription and expression of COX-2 in human myeloma RPMI8226 cells were checked by RT-PCR and Western blot analysis, respectively. The COX-2 siRNA fragment targeting exon 5 of COX-2 gene was transfected into the cells with the Amaxa nucleofection technique. The inhibition of cell growth was detected by 3-(4,5-dimethyl-2- thiazolyl)-2,5-diphenyl-2H-tetrazolium (MTT) assay. Apoptosis was estimated by Annexin-V/ propidium iodide double-labeled cytometry and confirmed by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay. Bcl-2 and Bax expression was evaluated by Western blot analysis.


RESULTS
The COX-2 siRNA fragment could be successfully transfected into RPMI8226 cells, which resulted in the significant inhibition of transcription and expression of COX-2 in the myeloma cells. Proliferation of the transfected cells was inhibited and apoptosis was induced (6.52%+/-0.32%, 12.53%+/-2.52%, 24.39%+/-3.51% and 36.48%+/-4.96% for 0, 12, 24, and 48 h, respectively) in a time-dependent manner (P<0.01). However, the expression of Bcl-2 and Bax in the RPMI8226 cells had no significant changes after nucleofection.


CONCLUSIONS
COX-2 siRNA transfection can suppress COX-2 expression in human myeloma RPMI8226 cells, which leads to growth inhibition and apoptosis independent of Bcl-2.
Li
Qiu-bai
QB
Department of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
Chen
Zhi-chao
ZC
You
Yong
Y
Zou
Ping
P
D017209:Apoptosis / Q000502:physiology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D051546:Cyclooxygenase 2 / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D009101:Multiple Myeloma / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism*; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D051028:bcl-2-Associated X Protein; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human