[Expression of phosphatidylinositol 3-kinase and effects of wortmannin on the expression of tumor necrosis factor-alpha in ulcerative colitis].
OBJECTIVE
To elucidate the role of phosphatidylinositol 3-kinase (PI3K)/Akt in the pathogenesis of ulcerative colitis (UC) and provide experimental evidence that PI3K inhibitor wortmannin can be used as a possible novel approach for treatment of UC.


METHODS
Samples of intestinal mucosa were collected from 30 UC patients, 22 males and 8 females, aged 35 +/- 11, during enteroscopy. Samples of normal intestinal mucosa 10 cm beyond the cancerous tissues were collected from 15 patients with intestinal cancer, 9 males and 6 females, aged 40 +/- 9, as normal controls. The samples underwent pathological examination and immunohistochemistry. Another tissues of intestinal mucosa were cultured and divided into 3 groups: UC + wortmannin group, (n = 10, wortmannin, an inhibitor of PI3K/Akt pathway, of the concentration of 0.002 nmol/microl was added), UC control group (n = 10, without addition of wortmannin), and peri-cancer normal intestinal tissue group (n = 10). 4.5 hours after the culture, immunohistochemistry was used to detect the expression of phosphorylated Akt (p-Akt) in the intestinal mucosa and ELISA was used to detect the content of tumor necrosis factor (TNF-alpha) in intestinal mucosa.


RESULTS
(1) The A value of p-Akt in the intestinal mucosa of the UC control group was 73.6 +/- 5.2, significantly higher than that of the normal control group (18.0 +/- 2.6, P < 0.05), the positive area of the UC control group was 720 +/- 58, significantly larger than that of the normal control group (133 +/- 29, P < 0.05). (2) The level of TNF-alpha in intestinal mucosa of the UC + wortmannin group was 135 +/- 11, significantly lower than that of the UC control group (296 +/- 39, P < 0.05), however, still significantly higher than that of the normal control group (26 +/- 5, P < 0.05). (3) The A value of p-Akt in the intestinal mucosa biopsy specimens of the UC + wortmannin group was 35.3 +/- 5.6, significantly lower than that of the UC control group (72.3 +/- 6.2, P < 0.05), however, still significantly higher than that of the normal control group (18.0 +/- 2.2, P < 0.05); and the positive area of the UC + wortmannin group was 351 +/- 50, significantly lower than that of the UC control group (716 +/- 94, P < 0.05), however, still significantly higher than that of the normal control group (129 +/- 30, P < 0.05).


CONCLUSIONS
(1) PI3K/Akt signal transduction pathway is a critical factor in regulating the expression of pro-inflammatory cytokine, and plays a role in the pathogenesis of UC. (2) Decreasing the levels of relevant cytokines in UC by inhibiting PI3K/Akt signal transduction pathway, wortmannin may be a novel approach for the treatment of UC.
Huang
Xiao-Li
XL
Department of Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China.
Yi
Wen-Quan
WQ
Zhang
Meng
M
Ouyang
Qin
Q
Gan
Hua-Tian
HT
D000328:Adult; D000730:Androstadienes / Q000627:therapeutic use*; D003093:Colitis, Ulcerative / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D019869:Phosphatidylinositol 3-Kinases / Q000096:biosynthesis; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D015398:Signal Transduction / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*; D000077191:Wortmannin
D000730:Androstadienes; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D014409:Tumor Necrosis Factor-alpha; D000077191:Wortmannin