MDR1-P-glycoprotein behaves as an oncofetal protein that promotes cell survival in gastric cancer cells
MDR1-P-glycoprotein behaves as an oncofetal protein that promotes cell survival in gastric cancer cells
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DOI：
10.1038/labinvest.2012.100
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发表时间：
2012-10-01
影响因子：
5
通讯作者：
Nardone, Gerardo
中科院分区：
文献类型：
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作者：
Rocco, Alba;Compare, Debora;Nardone, Gerardo
P-糖蛋白（P-gp）传统上与癌症不良预后和多药耐药性有关，在正常胃粘膜中检测不到，但在胃癌（GC）中过度表达。我们推测P-gp可能通过抑制细胞凋亡参与幽门螺杆菌（Hp）相关的胃癌发生。该研究的目的是评估胎儿胃中 P-gp 的表达和 Hp 相关胃癌发生、多药耐药 1 (MDR1) 基因的表观遗传控制、P-gp 和 Bcl-x(L) 之间的定位和相互作用以及选择性沉默 P-gp 对细胞存活的影响。通过免疫组织化学方法评估 28 名自然流产人类胎儿、66 名 Hp 阴性受试者、138 名 Hp 阳性慢性胃炎 (CG) 患者（其中 28 名肠化生 (IM) 和 45 名肠型 GC）的 P-gp 和 Bcl-xl 表达。在 GC 细胞系 AGS 和 MKN-28 以及肝细胞癌细胞系 Hep-G2 中，在基础条件下和应激诱导凋亡后，通过共聚焦免疫荧光显微镜研究了 P-gp/Bcl-x(L) 共定位，并通过共免疫沉淀研究了蛋白质相互作用。通过在应激的 AGS 和 MKN-28 细胞系中用特定的小干扰 RNA 敲低 P-gp 的表达来评估 P-gp 在控制细胞凋亡中的作用。 P-gp 在所有人类胎儿的胃粘膜中表达，而在成人正常粘膜中检测不到，并在 30/110 Hp 阳性非 IM-CG、28/28 IM-CG 和 40/45 GC 中重新表达。 P-gp 表达与 Bcl-x(L) 表达以及 MDR1 基因启动子低甲基化直接相关。在 GC 细胞系中，P-gp 定位在质膜和线粒体上，与 Bcl-x(L) 共定位。免疫共沉淀证实了 AGS、MKN-28 和 Hep-G2 中 P-gp 和 Bcl-x(L) 之间在基础水平和应激诱导细胞凋亡后的物理相互作用。 P-gp 的选择性沉默使 GC 细胞对应激诱导的细胞凋亡敏感。 P-gp 是一种癌胚蛋白，通过与 Bcl-x(L) 相互作用，在 Hp 相关胃癌发生中充当抗凋亡剂。实验室调查 (2012) 92, 1407-1418; doi：10.1038/labinvest.2012.100； 2012 年 7 月 2 日在线发布
P-glycoprotein (P-gp), traditionally linked to cancer poor prognosis and multidrug resistance, is undetectable in normal gastric mucosa and overexpressed in gastric cancer (GC). We propose that P-gp may be involved in Helicobacter pylori (Hp)-related gastric carcinogenesis by inhibiting apoptosis. Aim of the study was to evaluate the expression of P-gp in fetal stomach and in Hp-related gastric carcinogenesis, the epigenetic control of the multi-drug resistance-1 (MDR1) gene, the localization and interaction between P-gp and BcI-x(L) and the effect of the selective silencing of P-gp on cell survival. P-gp and Bcl-xl expression was evaluated by immunohistochemistry on 28 spontaneously abortive human fetuses, 66 Hp-negative subjects, 138 Hp-positive chronic gastritis (CG) of whom 28 with intestinal metaplasia (IM) and 45 intestinal type GCs. P-gp/BcI-x(L) colocalization was investigated by confocal immunofluorescence microscopy and protein protein interaction by co-immunoprecipitation, in basal conditions and after stress-induced apoptosis, in GC cell lines AGS and MKN-28 and hepatocellular carcinoma cell line Hep-G2. The role of P-gp in controlling apoptosis was evaluated by knocking down its expression with a specific small interfering RNAs in stressed AGS and MKN-28 cell lines. P-gp is expressed in the gastric mucosa of all human fetuses while, it is undetectable in adult normal mucosa and re-expressed in 30/110 Hp-positive non-IM-CG, 28/28 IM-CG and 40/45 GCs. P-gp expression directly correlates with that of BcI-x(L) and with the promoter hypomethylation of the MDR1 gene. In GC cell lines, P-gp is localized on the plasma membrane and mitochondria where it colocalizes with BcI-x(L). Co-immunoprecipitation confirms the physical interaction between P-gp and Bcl-x(L) in AGS, MKN-28 and Hep-G2, at both basal level and after stress-induced apoptosis. The selective silencing of P-gp sensitizes GC cells to stress-induced apoptosis. P-gp behaves as an oncofetal protein that, by cross-talking with Bcl-x(L), acts as an anti-apoptotic agent in Hp-related gastric carcinogenesis. Laboratory Investigation (2012) 92, 1407-1418; doi:10.1038/labinvest.2012.100; published online 2 July 2012