抑制HSF-1增强PS-341诱导胶质瘤细胞凋亡

目的探索HSF1是否能诱导HSPs的高表达,以及抑制HSF1是否能够增强PS-341诱导胶质瘤细胞凋亡。方法 Western检测HSP70、HSF1的表达,以及JNK的磷酸化。转染siRNA敲除HSF1,胎盘蓝染色及sub-G1检测细胞凋亡。结果胶质瘤细胞中HSP70及HSF1的表达明显高于正常脑组织。敲除HSF1能通过抑制HSP70明显增强PS-341诱导的胶质瘤细凋亡,并能增强及延长JNK通路的活化。在HSF1+/+细胞中,PS-341能够强烈诱导HSP70的表达;而在HSF1–/–细胞中,PS-341诱导并延长了JNK通路的激活。热休克预处理对两种细胞活性都没明显影响,但能明显增强HSF1+/+细胞对抗PS-341诱导凋亡的能力。结论胶质瘤细胞中,HSF1的激活能促进HSPs的表达,进而对抗PS-341诱导的细胞凋亡。抑制HSF-1能增强PS-341诱导胶质瘤细胞凋亡,这有望成为一种新的胶质瘤治疗途径。

Inhibition of heat shock factor1 response enhances PS-341-mediated glioma cell apoptosis

Objective Proteasome inhibitor have profound effects on tumor growth and cause cells to undergo apoptosis .PS-341,as an extremely potent and selective proteasome inhibitor , which is the first proteasome inhibitor to be used in clinical practice with the approve of FDA , can induces cell death via JNK pathway in vitro in glioma .However,suppressing proteasome complex by PS-341 may induce activation of heat shock factor 1 （ HSF1 ） , which can induce the expression of heat shock proteins （ HSPs ） to against cellular stress .In this study , we explored whether HSF 1 could induce expression of HSPs and whether inhibition of HSF 1 could enhance cell damage induced by PS-341 in glioma cells.Methods Surgically excised specimens from 30 patients with glioma （gradeⅡ-Ⅳ） and 10 normal brain control specimens obtained at autopsy were collected from the Department of Neurosurgery ,The First Affiliated Hospital of Harbin Medical University , China.The histological characteristics of 30 patients with glioma were established based on World Health Organization （WHO） criteria.The collected tissues were immediately snap-frozen in liquid nitrogen and stored at -80℃for Western blot analysis .Human U251MG and A172 glioblastoma cell lines were obtained from the Japanese Cancer Research Resources Bank .Western was used to detect the expression of HSPs , HSF1 and the activation of JNK .HSF1 was knocked down by siRNA ,then PS-341-induced cell damage was examined by Trypan blue exclusion assay and sub-G1 detection .Results HSP70 and HSF1 level were markedly higher in glioma tissues than in normal brain tissues .HSF1 knockdown significantly enhanced and prolonged JNK activation with strong inhibition of HSP 70.HSP70 was strongly induced by PS-341 in HSF1 ＋/＋cells, while PS-341 induced enhancement and prolongation of JNK activation in HSF1-/-cells.Pretreatment by heat shock had no effect on cell viability of both cells and significantly antagonized PS-341-induced cell death in HSF 1 ＋/＋cells.Conclutions Our resu