[Impact of STAT6 signaling pathway blockade on apoptosis of human colon cancer cells].
OBJECTIVE
To investigate the relationship between the signal transducer and activator of transcription 6 (STAT6) and human colon cancer.


METHODS
Four STAT6-specific recombinant plasmid vectors, pshRNA-STAT6-1, 2, 3, and 4 were constructed and transfected into the cultured human colon cancer cells of the line HT-29. Seventy-two hours later RT-PCR was used to detect the mRNA expression of STAT6 and the apoptosis-related genes Bcl-2 and Bax, flow cytometry (FCM) was used to detect the protein expression of phopho-STAT6 (pSTAT6). HT-29 cells were inoculated into a plate and transfected with pshRNA-STAT6-1 or pshRNA-STAT6-4, and HT-29 cells without transfection were used as controls. Seventy-two hours later FCM was used to observe the cell apoptosis. Another HT-29 cells were inoculated into a plate and transfected with pshRNA-STAT6-1 or pshRNA-STAT6-4, or blank liposome as controls. Seventy-two hours later. Western blotting was used to detect the protein expression of Bcl-2 and Bax genes.


RESULTS
The p-STAT6 protein expression rate was 3.2% +/- 0.6% in the pshRNA-STAT6-1 group, significantly lower than that of the blank control group (18.2% +/- 0.9%, P < 0.01) with an inhibition rate of 82.4%, and was 7.9% +/- 0.4% in the pshRNA-STAT6-4 group, significantly lower than that in the blank control group too (P < 0.01) with an inhibition rate of 56.6%. And the p-STAT6 protein expression rates of the pshRNA-STAT6-2 and pshRNA-STAT6-3 groups were 16.6% +/- 0.5% and 17.1% +/- 0.7% respectively, both not significant different from that of the blank control group (both P > 0.05). The early cell apoptosis rates of the pshRNA-STAT6-1 and pshRNA-STAT6-4 groups were 13.0% and 8.8% respectively, both significantly higher than that of the blank control group (0.4%, both P < 0.05). The mRNA expression of Bcl-2 was significantly lower and the mRNA expression of Bax was significantly higher in the pshRNA-STAT6-1 and pshRNA-STAT6-4 groups than in the blank control and blank liposome groups (all P < 0.01). The protein expression patterns of Bcl-2 and Bax was consistent with that of their protein expression.


CONCLUSIONS
STAT6 signaling pathway inhibits the apoptosis of colon cancer cells by regulation of the Bcl-2 and Bax genes.
Zhang
Ming-sheng
MS
Depmartment of Cancer Radio-Chemotherapy, Zhongnan Hospital of Wuhan University, Wuhan 430071, China.
Zhou
Yun-feng
YF
Xie
Cong-Hua
CH
Zhang
Wen-jie
WJ
Zhou
Fu-xiang
FX
Qu
Xue-ju
XJ
D017209:Apoptosis / Q000235:genetics / Q000502:physiology*; D015153:Blotting, Western; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D005434:Flow Cytometry; D019073:HT29 Cells; D006801:Humans; D010766:Phosphorylation; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050800:STAT6 Transcription Factor / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D014162:Transfection; D051028:bcl-2-Associated X Protein / Q000378:metabolism
C494826:BAX protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D050800:STAT6 Transcription Factor; D051028:bcl-2-Associated X Protein