Differential Expression of PKC Isoforms and Their Tumoricidal Activity in Two Macrophage Cell Lines: Involvement of Nitric Oxide-dependent Mechanisms  

两种巨噬细胞系中PKC亚型表达的差别与其抗瘤活性的比较:依赖一氧化氮的杀瘤机制(英文)

作　　者：刘辉[1] 曹惠芳[1] 孙为民[1] 徐仁宝[1] 吴孟超[1] 王红阳[1] 

机构地区：[1]上海第二军医大学东方肝胆外科医院,国际合作信号转导研究所,200438

出　　处：《The Chinese-German Journal of Clinical Oncology》2004年第2期101-105,126,127,共7页中德临床肿瘤学杂志（英文版）

摘　　要：Objective: To investigate the role of PKC isoforms in the regulation of LPS-triggered tumoricidal activity in macrophages and further elucidate its signal mechanisms. Methods: Two macrophage cell lines (P388D1 and RAW264.7) were stimulated by LPS alone, or with long-term of PMA pretreatment. Then cytotoxicities to P815 cells (by MTT assay) and IL-1, TNF- (by ELISA) and nitric oxide (NO) production (by Griess reagent) in supernatants were measured. Western blot for PKC isoforms after long-term PMA pretreatment was analyzed. Results: RAW264.7 cells were stimulated with LPS to kill target tumor cells P815, whereas P388D1 cells failed to develop such an ability. Down-regulation of PKC isoforms by chronic treatment with PMA significantly inhibited the LPS-induced cytotoxicity in RAW264.7 cells. In unstimulated state, Western blotting with rabbit antiserum specific for the PKC, 1, 2, or showed all 5 isoforms were detected in P388D1 cells, while only PKC, PKC1 and PKC were detected in RAW264.7 cells. Exposure of the cells to long-term of PMA treatment significantly down-regulated the expression of PKC, PKC1 and PKC in RAW264.7 cells. But in P388D1 cells, although PKC, PKC and PKC were down-regulated, the expression of PKC1 and PKC2 could not be regulated. Comparing with LPS-induced IL-1, TNF- and NO production by the two macrophage cell lines, P388D1 failed to produce NO. In RAW264.7 cells, LPS-induced NO production and antitumor activity was attenuated by the addition of L-NAME, an iNOS inhibitor. Conclusion: The results indicated a critical role of PKC in LPS-induced antitumor activity and this cytotoxicity is mainly due to PKC- mediated NO production by RAW264.7 cells, but not a direct cytotoxic activity.

关 键 词：lippolysaccaride PKC isoforms MACROPHAGES nitric oxide CYTOTOXICITY 

分 类 号：R73-36[医药卫生—肿瘤]