title: Notch2-induced COX-2 expression enhancing gastric cancer progression.
abstract: Gastric carcinoma is one of the most common and mortal types of malignancy worldwide. To date, the mechanisms controlling its aggressiveness are not yet fully understood. Notch signal pathway can function as either an oncogene or a tumor suppressor in tumorigenesis. Four members (Notch1-4) of Notch receptors were found in mammals and each exhibits distinct roles in tumor progression. Previous study showed that the activated Notch1 receptor promoted gastric cancer progression through cyclooxygenase-2 (COX-2). This study addressed whether Notch2 signal pathway is also involved in gastric cancer progression. Constitutive expression of Notch2 intracellular domain (N2IC), the activated form of Notch2 receptor, promoted both cell proliferation and xenografted tumor growth of human stomach adenocarcinoma SC-M1 cells. The colony formation, migration, invasion, and wound-healing abilities of SC-M1 cells were enhanced by N2IC expression, whereas these abilities were suppressed by Notch2 knockdown. Similarly, Notch2 knockdown inhibited cancer progressions of AGS and AZ521 gastric cancer cells. Expression of N2IC also caused epithelial-mesenchymal transition in SC-M1 cells. Furthermore, N2IC bound to COX-2 promoter and induced COX-2 expression through a CBF1-dependent manner in SC-M1 cells. The ability of N2IC to enhance tumor progression in SC-M1 cells was suppressed by knockdown of COX-2 or treatment with NS-398, a COX-2 inhibitor. Moreover, the suppression of tumor progression by Notch2 knockdown in SC-M1 cells was reversed by exogenous COX-2 or its major enzymatic product PGE(2) . Taken together, this study is the first to demonstrate that the Notch2-COX-2 signaling axis plays an important role in controlling gastric cancer progression.
authors: Department of Anatomy and Cell Biology, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors: Yun-Chien
authors: YC
authors: Tseng
authors: Yu-Hui
authors: YH
authors: Tsai
authors: Min-Jen
authors: MJ
authors: Tseng
authors: Kai-Wen
authors: KW
authors: Hsu
authors: Min-Chieh
authors: MC
authors: Yang
authors: Kuo-Hung
authors: KH
authors: Huang
authors: Anna Fen-Yau
authors: AF
authors: Li
authors: Chin-Wen
authors: CW
authors: Chi
authors: Rong-Hong
authors: RH
authors: Hsieh
authors: Hung-Hai
authors: HH
authors: Ku
authors: Tien-Shun
authors: TS
authors: Yeh
mesh_terms: D000818:Animals; D001483:Base Sequence; D045744:Cell Line, Tumor; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D017931:DNA Primers; D018450:Disease Progression; D055785:Gene Knockdown Techniques; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D060888:Real-Time Polymerase Chain Reaction; D051883:Receptor, Notch2 / Q000235:genetics / Q000502:physiology*; D013274:Stomach Neoplasms / Q000235:genetics / Q000473:pathology*
chemical_list: D017931:DNA Primers; C497764:NOTCH2 protein, human; D051883:Receptor, Notch2; D051546:Cyclooxygenase 2