Jiang Xuejun, Kim Hyun-Eui, Shu Hongjun, Zhao Yingming, Zhang Haichao, Kofron James, Donnelly Jennifer, Burns Dave, Ng Shi-Chung, Rosenberg Saul, Wang Xiaodong
Howard Hughes Medical Institute, Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
Science. 2003 Jan 10;299(5604):223-6. doi: 10.1126/science.1076807.
A small molecule, alpha-(trichloromethyl)-4-pyridineethanol (PETCM), was identified by high-throughput screening as an activator of caspase-3 in extracts of a panel of cancer cells. PETCM was used in combination with biochemical fractionation to identify a pathway that regulates mitochondria-initiated caspase activation. This pathway consists of tumor suppressor putative HLA-DR-associated proteins (PHAP) and oncoprotein prothymosin-alpha (ProT). PHAP proteins promoted caspase-9 activation after apoptosome formation, whereas ProT negatively regulated caspase-9 activation by inhibiting apoptosome formation. PETCM relieved ProT inhibition and allowed apoptosome formation at a physiological concentration of deoxyadenosine triphosphate. Elimination of ProT expression by RNA interference sensitized cells to ultraviolet irradiation-induced apoptosis and negated the requirement of PETCM for caspase activation. Thus, this chemical-biological combinatory approach has revealed the regulatory roles of oncoprotein ProT and tumor suppressor PHAP in apoptosis.
一种小分子α-(三氯甲基)-4-吡啶乙醇（PETCM），通过高通量筛选被鉴定为一组癌细胞提取物中半胱天冬酶-3的激活剂。PETCM与生化分级分离相结合，以鉴定一条调节线粒体启动的半胱天冬酶激活的途径。该途径由肿瘤抑制因子假定的HLA-DR相关蛋白（PHAP）和癌蛋白前胸腺素α（ProT）组成。PHAP蛋白在凋亡小体形成后促进半胱天冬酶-9的激活，而ProT通过抑制凋亡小体的形成对半胱天冬酶-9的激活起负调节作用。PETCM解除了ProT的抑制作用，并在生理浓度的三磷酸脱氧腺苷下使凋亡小体形成。通过RNA干扰消除ProT的表达使细胞对紫外线照射诱导的凋亡敏感，并消除了PETCM对半胱天冬酶激活的需求。因此，这种化学生物学组合方法揭示了癌蛋白ProT和肿瘤抑制因子PHAP在凋亡中的调节作用。
