結構相似性類黃酮素化合物對上皮生長因子誘導上皮腫瘤細胞A431增生作用之抑制活性研究

中文摘要經由上皮生長因子(EGF)所誘導的訊息傳遞路徑已被證實與腫瘤的發生有密切的關聯性，而能夠抑制上皮生長因子所誘導之細胞增生的藥物則可能用來預防癌症的形成。人體內的環氧脢(cyclooxygenase, COX)在生理與病理上扮演重要的角色，其中COX-2在最近的研究中指出與許多癌症的形成和惡化有關，其反應產物PGE2也會促使癌細胞轉移並侵犯周圍組織。本實驗中我們針對九種具有結構相關性的類黃酮素包括：flavone，3-OH flavone (flavonol)，5-OH flavone (primuletin)，7-OH flavone，kaempferol，quercetin， myricetin，baicalein，以及morin探討其對上皮生長因子誘導A431表皮癌化細胞增生的抑制作用。當以EGF(10 ng/ml)處理A431細胞時，可使細胞大量增生並且促使上皮生長因子受器(EGFR)與ERKs磷酸化。而對於total EGFR，JNK，p38則沒有影響。以EGF處理的細胞也可以觀察到具有時間依循性的COX-2誘導現象。當前處理MAPK專一性抑制劑PD98059後，可以阻斷EGF所誘導的MAPK磷酸化，COX-2活化及細胞增生。非類固醇消炎藥(NSAIDs)如aspirin與diclofenac則可經由抑制COX-2活性達到抑制EGF誘導的PGE2生成與細胞增生的效果。若在培養液裡外加PGE2則可以使PD98059，NSAIDs，3-OH flavone所抑制的細胞增生復原。在菌落形成(colony formation)與轉移(metastasis)實驗中，PD98059，NSAIDs，3-OH flavone可以抑制受EGF所誘導的A431轉型(transformation)與轉移活性(metastasis activity)。由實驗的結果發現，PGE2是EGF誘導細胞增生時重要的介質，而EGF所活化的COX-2則位在MAPK磷酸化的下游。從分析flavones對EGF誘導增生的抑制作用發現，3-OH flavone對EGF誘導的A431細胞中EGFR與MAPK磷酸化，COX-2活化以及細胞增生有明顯的抑制作用。我們認為3-OH flavone應可做為預防細胞受到EGF刺激而增生的有效藥物。

關鍵字

類黃酮素；上皮生長因子

並列摘要

Abstract Activation of epidermal growth factor (EGF)-induced signaling transduction has been demonstrated to be associated closely with the occurrence of tumor, and agent inhibited EGF-induced proliferation was proposed to be beneficial in preventing cancer formation. Cyclooxygenase (COX) has been demonstrated to be important in tumorgenesis and malignant properties. On the other hand, PGE2, the product of COX-2 enzymetic reaction, also involved in tumor migration and invasion. Here, we investigated the inhibitory effects of nine structure-related flavones including flavone, 3-OH flavone (flavonol), 5-OH flavone (primuletin), 7-OH flavone, kaempferol, quercetin, myricetin, baicalein, and morin on EGF-induced signaling transduction and proliferation in A431 epidermoid carcinoma cells. Treatment of A431 cells with EGF (10 ng/ml) induced proliferation, accompanied by phosphorylation of EGF receptor (EGFR) and extracellular activated protein kinases (ERKs). However, total EGFR, phosphorylated c-Jun N-terminal kinases (JNK), phosphorylated p38 proteins were remained unchanged. Time dependent induction of cyclooxygenase 2 (COX-2) protein was detected in EGF-treated cells. Pretreatment of cells with PD98059, a specific inhibitor of MAPKs, blocked EGF-induced MAPK phosphorylation, COX-2 activation and cellular proliferation. NSAIDs including aspirin and diclofenac significantly inhibited EGF-induced PGE2 production, at the same time, suppressed EGF-induced proliferation through blocking the activity of COX-2. Treatment with exogenous PGE2 can recover cell proliferation inhibited by PD98059, NSAIDs and 3-OH flavone. In colony formation assay and metastasis assay, PD98059, NSAIDs and 3-OH flavone can inhibit EGF-induced A431 transformation and metastasis activity. These data indicated PGE2 is a proliferative molecule in EGF-induced proliferation, and activation of COX-2 located at the down-stream of MAPK phosphorylation. Upon analysis of the inhibitory effects of flavones on EGF-induced proliferation, the results appeared that 3-OH flavone showed the significant inhibition on EGF-induced EGFR phosphorylation, MAPK phosphorylation, COX-2 activation and proliferation in A431 cells. We proposed that 3-OH flavone is an effective agent in preventing cells from EGF-induced proliferation.

並列關鍵字

flavones ； epidermal growth factor

參考文獻

1. 行政院衛生署九十年公告台灣地區主要死因 2. Ebert AD, Wechselberger C, Martinez-Lacaci I, Bianco C, Weitzel HK, Salomon DS. Expression and function of EGF-related peptides and their receptors in gynecological cancer — from basic science to therapy? J. Recep. Signal Transduction Res. 20(1):1-46, 2000 3. Yoshida J, Ishibashi T, Nishio M. Growth-inhibitory effect of a streptococcal antitumor glycoprotein on human epidermoid carcinoma A431 cells: involvement of dephosphorylation of epidermal growth factor receptor. Cancer Res. 61: 6151-6157, 2001 4. Yarden Y. The EGFR family and its ligands in human cancer: signalling mechanism and therapeutic opportunities. Eur. J. Cancer 37 Suppl. 4: S3-S8, 2001 5. Wells A. EGF receptor. The Int. J. of Biochem. and Cell Biol. 31(6): 637-643, 1999 6. Bishayee S. Role of conformational alteration in the epidermal growth factor receptor (EGFR) function. Biochem. Pharmacol. 60: 1217-1223, 2000 7. Dempke W, Rie C, Grothey A, Schmoll H-J. Cyclooxygenase-2: a novel target for cancer chemotherapy? J. Cancer Res. Clin. Oncol. 127(7): 411-417, 2001 8. Dannhardt G, Kiefer W. Cyclooxygenase inhibitors — current status and future prospects. Eur. J. Med. Chem. 36: 109-126, 2001 9. Watanabe K, Kawamori T, Nakatsugi S, Wakabayashi K. COX-2 and iNOS, good targets for chemoprevention of colon cancer. Biofactors 12(1-4): 129-133, 2000 10. Chen WS, Wei SJ, Liu JM, Hsiao M, Lin JK, Yang WK. Tumor invasiveness and liver metastasis of colon cancer cells correlated with cyclooxygenase-2 (COX-2) expression and inhibited by a COX-2-selective inhibitor, etodolac. Int. J. Cancer 91: 894-899, 2001

Google Scholar

國際替代計量

結構相似性類黃酮素化合物對上皮生長因子誘導上皮腫瘤細胞A431增生作用之抑制活性研究

未授權

主題瀏覽