Collagen Gel Overlay Induces Apoptosis of Epithelial Cells

• Main Authors: Hu, Jeng-Jay, 胡政杰
• Other Authors: Tang Ming-Jer
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/18118420913367585384

碩士 === 國立成功大學 === 生理學研究所 === 84 === In this study, I attempted to investigate the response of epithelial cellswhen they interact with the extracellular matrix in an inappropriate orient-ation. Cell lines of epithelial (MDCK, LLC-PK1), endothelial (BAEC) and mesen-chymal (ESK-4 and NIH-3T3) origins were employed. Under collagen gel overlay,MDCK cells lost the epithelial morphology and underwent cell-cell dissociationas early as 12 hr and they transformed into tubule- like structure at about 24hr. However,they developed apoptosis, as confirmed by fragmented DNA analysis,Hoechst 33258 staning and also flow cytometrical analysis, within 24-48 hrafter collagen gel overlay. Finally, widespread of apoptosis was observedwithin 3 days of collagen overlay. The cell death was not caused by the physi-cal effect (eg. gravity), because agarose gel overlay did not induce any mor-phological changes. LLC-PK1 and BAEC cells also developed similar phenomenon.In contrast, collagen gel overlay did not inhibit the growth of fibroblasts atall. The collagen gel overlay-induced apoptosis seems to be a unique phenome-non for polarized cells. We have termed this phenomenon as "disoriented celldeath". Furthermoore, cycloheximide-treated MDCK cells could circumvent dis-oriented cell death, indicating that newly synthesized proteins were involvedin the mechanism. Neither the treatment of scatter factor (HGF), nor low celldensity could prevent MDCK cells from disoriented cell death. However, over-expression of bcl-2 conferred resistance to disoriented cell death. Finally, since disoriented cell death could be alleviated by monoclonal antibodiesagainst a2 integrin subunit, signals tranduced from a2 integrin seemed to me-diate collagen gel overlay-induced response.