Protection of glioblastoma cells from cisplatin cytotoxicity via protein kinase Cι-mediated attenuation of p38 MAP kinase signaling
Protection of glioblastoma cells from cisplatin cytotoxicity via protein kinase Cι-mediated attenuation of p38 MAP kinase signaling
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DOI：
10.1038/sj.onc.1209312
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发表时间：
2006-05-01
期刊：
影响因子：
8
通讯作者：
Lorimer, I. A. J.
中科院分区：
文献类型：
--
作者：
Baldwin, R. M.;Garratt-Lalonde, M.;Lorimer, I. A. J.
多形性胶质母细胞瘤是一种侵袭性的脑癌，对化疗反应差，通常是无法治愈的。这种癌症对化疗反应差的原因尚不清楚。非典型蛋白激酶C(PKC Iota和PKC Zeta)以前被认为与白血病细胞的化疗耐药有关。为探讨非典型PKC在胶质母细胞瘤细胞化疗耐药中的作用，采用RNA干扰技术耗尽人胶质母细胞瘤细胞的PKC。用两种不同的针对PKC的RNA双链中的任何一种对化疗药物顺铂诱导的细胞死亡部分敏感。为了筛选PKC IOTA介导的化疗耐药的可能机制，对未经处理或PKC IOTA缺失的胶质母细胞瘤细胞的RNA进行了基因表达的微阵列分析。这确定了一组受PKC IOTA正向或负向调控的基因。在被PKC IOTA负调控的一组基因中，进一步研究了p38丝裂原活化蛋白激酶(MAP)信号的增强子GMFβ编码基因的功能，因为p38 MAP激酶途径已被确定为顺铂细胞毒性的关键介质。当PKC I耗尽时，GMFb mRNA和蛋白的表达均增加，并伴随着顺铂激活的p38 MAP激酶信号的增加。GMFb的瞬时过表达增加了顺铂激活的p38 MAP激酶信号，并使细胞对顺铂的细胞毒性变得敏感。P38丝裂原活化蛋白激酶抑制剂SKF86002可阻断PKCI耗竭引起的顺铂细胞毒性增加。这些数据表明，PKCi可以通过抑制GMFβ介导的p38 MAP激酶信号的增强而使胶质母细胞瘤细胞对顺铂产生部分耐药。
Glioblastoma multiforme is an aggressive form of brain cancer that responds poorly to chemotherapy and is generally incurable. The basis for the poor response of this cancer to chemotherapy is not well understood. The atypical protein kinases C ( PKC iota andPKC zeta) have previously been implicated in leukaemia cell chemoresistance. To assess the role of atypical PKC in glioblastoma cell chemoresistance, RNA interference was used to deplete human glioblastoma cells of PKC iota. Transfection of cells with either of two different RNA duplexes specific for PKC iota causeda partial sensitisation to cell death induced by the chemotherapy agent cisplatin. To screen for possible mechanisms for PKC iota- mediated chemoresistance, microarray analysis of gene expression was performed on RNA from glioblastoma cells that were either untreated or depleted of PKC iota. This identified sets of genes that were regulated either positively or negatively by PKC iota. Within the set of genes that were negatively regulated by PKC iota, the function of the gene coding for GMF beta, an enhancer of p38 mitogen- activated-protein kinase ( MAP kinase) signaling, was investigated further, as the p38 MAP kinase pathway has been previously identified as a key mediator of cisplatin cytotoxicity. The expression of both GMFb mRNA and protein increased upon PKC iota depletion, and this was accompanied by an increase in cisplatin- activated p38 MAP kinase signaling. Transient overexpression of GMFb increased cisplatin-activated p38 MAP kinase signaling and also sensitised cells to cisplatin cytotoxicity. The increase in cisplatin cytotoxicity seen with PKCi depletion was blocked by the p38 MAP kinase inhibitor SKF86002. These data show that PKCi can confer partial resistance to cisplatin in glioblastoma cells by suppressing GMF beta- mediated enhancement of p38 MAP kinase signaling.