Downregulation of uPAR and cathepsin B induces apoptosis via regulation of Bcl-2 and Bax and inhibition of the PI3K/Akt pathway in gliomas.
Downregulation of uPAR and cathepsin B induces apoptosis via regulation of Bcl-2 and Bax and inhibition of the PI3K/Akt pathway in gliomas.
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DOI：
10.1371/journal.pone.0013731
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发表时间：
2010-10-29
期刊：
影响因子：
3.7
通讯作者：
Rao JS
中科院分区：
文献类型：
--
作者：
Malla R;Gopinath S;Alapati K;Gondi CS;Gujrati M;Dinh DH;Mohanam S;Rao JS
胶质瘤是最常见的原发性脑肿瘤，其特征在于侵袭性和浸润性行为。已知uPAR和组织蛋白酶B在高级别胶质瘤中过表达，并且与侵袭性癌症表型强烈相关。在本研究中，我们观察到，同时下调uPAR和组织蛋白酶B诱导上调一些促凋亡基因和抑制抗凋亡基因在人脑胶质瘤细胞。uPAR和组织蛋白酶B（pCU）下调的细胞表现出Bcl-2/Bax比值的降低，并引发线粒体膜电位的崩溃。我们还观察到广泛的caspase抑制剂Z-Asp-2，6-dichlorobenzoylmethylketone在U251细胞中挽救了pCU诱导的凋亡，但在5310细胞中没有。Caspase-9免疫沉淀物的Apaf-1的免疫印迹分析表明，uPAR和组织蛋白酶B敲低激活U251细胞中的溶酶体复合物的形成。U251和5310细胞中uPAR和组织蛋白酶B的下调也阻碍了核转位并干扰了CREB的DNA结合活性。进一步的蛋白质印迹分析表明uPAR和组织蛋白酶B的下调显著降低了信号分子p-PDGFR-β、p-PI 3 K和p-Akt的表达。裸鼠脑肿瘤切片和脑组织裂解物中TUNEL阳性细胞数量的增加、Bax表达的增加和Bcl-2表达的减少证实了我们的体外结果。总之，RNAi介导的uPAR和组织蛋白酶B的下调在U251细胞中启动caspase依赖性线粒体凋亡，在5310细胞中启动caspase非依赖性线粒体凋亡。因此，使用siRNA靶向uPAR和组织蛋白酶B介导的信号传导可作为治疗神经胶质瘤的新的治疗策略。
Glioma is the most commonly diagnosed primary brain tumor and is characterized by invasive and infiltrative behavior. uPAR and cathepsin B are known to be overexpressed in high-grade gliomas and are strongly correlated with invasive cancer phenotypes. In the present study, we observed that simultaneous downregulation of uPAR and cathepsin B induces upregulation of some pro-apoptotic genes and suppression of anti-apoptotic genes in human glioma cells. uPAR and cathepsin B (pCU)-downregulated cells exhibited decreases in the Bcl-2/Bax ratio and initiated the collapse of mitochondrial membrane potential. We also observed that the broad caspase inhibitor, Z-Asp-2, 6-dichlorobenzoylmethylketone rescued pCU-induced apoptosis in U251 cells but not in 5310 cells. Immunoblot analysis of caspase-9 immunoprecipitates for Apaf-1 showed that uPAR and cathepsin B knockdown activated apoptosome complex formation in U251 cells. Downregulation of uPAR and cathepsin B also retarded nuclear translocation and interfered with DNA binding activity of CREB in both U251 and 5310 cells. Further western blotting analysis demonstrated that downregulation of uPAR and cathepsin B significantly decreased expression of the signaling molecules p-PDGFR-β, p-PI3K and p-Akt. An increase in the number of TUNEL-positive cells, increased Bax expression, and decreased Bcl-2 expression in nude mice brain tumor sections and brain tissue lysates confirm our in vitro results. In conclusion, RNAi-mediated downregulation of uPAR and cathepsin B initiates caspase-dependent mitochondrial apoptosis in U251 cells and caspase-independent mitochondrial apoptosis in 5310 cells. Thus, targeting uPAR and cathepsin B-mediated signaling using siRNA may serve as a novel therapeutic strategy for the treatment of gliomas.
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影响因子：
5.2
作者：
Gondi CS;Talluri L;Dinh DH;Gujrati M;Rao JS
通讯作者：
Rao JS
影响因子：
8
作者：
Gopinath, Sreelatha;Vanamala, Sravan K.;Gujrati, Meena;Klopfenstein, Jeffrey D.;Dinh, Dzung H.;Rao, Jasti S.
通讯作者：
Rao, Jasti S.
影响因子：
3.7
作者：
Gopinath S;Malla RR;Gondi CS;Alapati K;Fassett D;Klopfenstein JD;Dinh DH;Gujrati M;Rao JS
通讯作者：
Rao JS
影响因子：
5.7
作者：
Gondi, Christopher S.;Kandhukuri, Neelima;Rao, Jasti S.
通讯作者：
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影响因子：
4.8
作者：
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通讯作者：
Montminy, M