P-158 YI Antiinflammatory Effects of Protein Kinase Inhibitor Pyrrole Derivate Having Antitumor Activity

Abstract

In our previous studies we showed antitumor activity of pyrrole derivate 1-(4-Cl-benzyl)-3-Cl-4-(CF3-fenylamino)-1H-pyrrol-2,5-dione (MI-1) on in vitro (cell lines of human colorectal adenocarcinoma COLO205, SW-620) and in vivo (1,2-dimethylhydrazine-induced rat colon cancer) models. MI-1 is an inhibitor of protein kinases EGFR, VEGFR, IGF1R, Src, PDK1, which are overexpressed in human colorectal tumors. It is known that EGFR and IGF1R can activate PI3K/Akt and following NF-κB signaling pathways. EGFR can also activate Jak/STAT pathway. PDK1 and Src are the key effectors of PI3K/Akt pathway. The consequence of activation of these signaling pathways, in addition to the induction of cell proliferation and survival, are pro-inflammatory effect. Furthermore, the roles of inflammation and oxidative stress in tumor initiation and progression are acknowledged, as well as their close relationship. So antiinflammatory properties of MI-1 as an inhibitor of named kinases were assumed, and the antiinflammatory and antioxidant effects of MI-1 on rat ulcerative colitis model were aimed to be discovered. Acetic acid induced ulcerative colitis model was used. Forty Male Wistar rats were induced by 2 rectal applications of 4% acetic acid (1 mL) weekly. MI-1 (2.7 mg/kg) and a reference drug prednisolone (0.7 mg/kg) administrations were provided daily for 14 days starting simultaneously with the 1st acetic acid application. The internal bowel surface was visually inspected, the integrity of bowel mucosa and inflammatory features were evaluated by 10 and 11 grade scales on macro- (Sehirli A, 2009) and light microscopy levels (Appleyard CB, 1995) respectively, and the grade of total injury (GTI) was calculated. Thiobarbituric acid active products (TBAP), protein carbonyl groups (PCG), intracellular superoxide dismutase (SOD) and catalase (CAT) activities as indicators of colon mucosa redox status were measured spectrophotometrically in bowel mucosa homogenates. Colonic clefts and small ulcers, edema, epithelium desquamation and inflammatory features manifested by submucosa lymphoid and histiocytic infiltration and extravasation appeared under colitis condition. GTI was equal to 10 (GTIcontrol = 0). Increase of TBAP (by 89%) and PCG (by 60%) and decrease of SOD (by 40%) in bowel mucosa were observed. Prednisolone escaped the ulcers, edema and epithelium desquamation, and decreased GTI to 3—some inflammatory features (lymphoid and histiocytic infiltration of submucosa) were persisted. SOD activity was leveled by prednisolone, but TBAP and PCG remained higher than control ones by 52% and 42% respectively. MI-1 restored colon mucosa integrity, decreased mucosa inflammation down to local foci of lymphocytes and histiocytes (GTI = 1), leveled TBAP, PCG and SOD. MI-1 possessed antiinflammatory properties more expressed that prednisolone ones, as well as normalized mucosa redox balance. Since antiinflammatory effects of glucocorticoids are realized through inhibition of phospholipase A2 followed prostaglandins synthesis decrease, and less through COX-2 inhibition, thereat effects of MI-1 through inflammatory signaling pathways are multiple, probably determining MI-1 more expressed and complex impact on inflammatory process. Thus MI-1 has a prospect for correction of inflammatory and carcinogenesis processes through multiple mechanisms of action.