p53－－控制細胞生長及凋零的重要因子

p53-The Main Control Factor of Cell Proliferation and Apoptosis

p53是控制細胞增殖主要的因素之一，其可抑制細胞的生長和轉形。一個普遍的觀念，認為p53扮演著“基因庫的守衛者”的角色，藉由阻止帶有損傷的DNA之細胞進行增殖，而可暫時的將細胞環之進行停止，直到損傷被修復；另外，又可永久的藉由將受損的細胞推向不可逆的細胞凋零機轉，導致細胞死亡。近來的研究顯示：p53的活化基因p21cip1/waf1/sdi1為－cyclin-kinase的抑制者，可調控p53依賴性的細胞環停止，故當DNA受損導致細胞計劃性死亡，需要轉錄活化p53，卻不需活化p21cip1/waf1/sdi1。本文之目的，即在闡明p53與P21cip1/waf1/sdi1在控制癌細胞的增殖，與腫瘤的細胞凋零上，所扮演的角色。

P53 is one of the major factors controlling cell proliferation, suppressing both growth and transformation of cells. A prevalent idea is that p53 acts as ”guardian of the genome” by preventing cells bearing damaged DNA form proliferating, either temporarily, by arresting the cell division cycle until damage is repaired, or permanently, by pushing the damaged cell down an irreversible apoptotic pathway of cell suicide. Current research highlights the action of a p53-activated gene, p21cip1/waf1/sdi1, which encodes a cyclin-kinase inhibitor important in mediating p53-dependent cell-cycle arrest, while programmed cell death in response to DNA damage requires tran-scriptionally active p53 but not activation of p21cip1/waf1/sdi1. This review will examine the roles of p53 and p21cip1/waf1/sdi1 in controlling cancer cell proliferation and tumor apoptosis.