Overexpression of cyclin D1 promotes tumor cell growth and confers resistance to cisplatin-mediated apoptosis in an elastase-myc transgene-expressing pancreatic tumor cell line
Overexpression of cyclin D1 promotes tumor cell growth and confers resistance to cisplatin-mediated apoptosis in an elastase-myc transgene-expressing pancreatic tumor cell line
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DOI：
10.1158/1078-0432.ccr-04-2419
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发表时间：
2005-08-15
影响因子：
11.5
通讯作者：
Liao, JD
中科院分区：
文献类型：
--
作者：
Biliran, H;Wang, Y;Liao, JD
目的：胰腺癌细胞周期蛋白D1升高与预后不良相关。由于胰腺癌总是对化疗有耐药性，本研究的目的是研究胰腺癌细胞的耐药是否部分归因于cyclin D1过表达。实验设计：在新建立的Ela-myc胰腺肿瘤细胞系中稳定过表达和siRNA介导的细胞周期蛋白D1的下调。通过3-（4,5-二甲基噻唑-2-基）-2,5-二苯基溴化四唑、克隆性和凋亡测定[DNA片段、亚g(1)和聚（adp -核糖）聚合酶裂解分析]来确定对照细胞、过表达细胞和sirna转染细胞的顺铂敏感性。采用EMSA和Western blotting分别检测核因子κ B和凋亡蛋白在细胞周期蛋白d1介导的化疗耐药中的作用。结果：cyclin D1在Ela-myc胰腺肿瘤细胞中过表达，促进细胞增殖和非锚定生长。此外，通过3-（4,5-二甲基噻唑-2-基）-2,5-二苯基溴化四唑和克隆致生实验，cyclin D1 -过表达的细胞在顺铂治疗后表现出明显降低的化学敏感性和更高的存活率。虽然细胞周期蛋白D1的过表达使细胞对顺铂诱导的凋亡更有抵抗力，但sirna定向抑制细胞周期蛋白D1的表达导致细胞对顺铂介导的凋亡的易感性增强。顺铂诱导的细胞死亡在cyclin D1 -过表达细胞中的衰减与核因子κ B活性的上调和bcl-2和bcl-xl蛋白水平的维持有关。结论：cyclin D1的过度表达可能参与胰腺癌细胞的化疗耐药，这是因为cyclin D1具有促进细胞增殖和抑制药物诱导的细胞凋亡的双重作用。
Purpose: Elevated cyclin D1 in human pancreatic cancer correlates with poor prognosis. Because pancreatic cancer is invariably resistant to chemotherapy, the goal of this study was to examine whether the drug resistance of pancreatic cancer cells is in part attributed to cyclin D1 overexpression.Experimental Design: Stable overexpression and small interfering RNA (siRNA)- mediated knockdown of cyclin D1 were done in the newly established Ela-myc pancreatic tumor cell line. Cisplatin sensitivity of control, overexpressing, and siRNA-transfected cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, clonogenic, and apoptotic assays [DNA fragmentation, sub-G(1), and poly (ADP-ribose) polymerase cleavage analysis]. The role of nuclear factor-kappa B and apoptotic proteins in cyclin D1-mediated chemoresistance was examined by EMSA and Western blotting, respectively.Results: Overexpression of cyclin D1 in Ela-myc pancreatic tumor cells promoted cell proliferation and anchorage-independent growth. Moreover, cyclin D1 - overexpressing cells exhibited significantly reduced chemosensitivity and a higher survival rate upon cisplatin treatment, as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and clonogenic assays, respectively. Although overexpression of cyclin D1 rendered cells more resistant to cisplatin-induced apoptosis, siRNA-directed suppression of cyclin D1 expression resulted in enhanced susceptibility to cisplatin-mediated apoptosis. The attenuation of cisplatin-induced cell death in cyclin D1 - overexpressing cells was correlated with the up-regulation of nuclear factor-kappa B activity and maintenance of bcl-2 and bcl-xl protein levels.Conclusions: These results suggest that overexpression of cyclin D1 can contribute to chemoresistance of pancreatic cancer cells because of the dual roles of cyclin D1 in promoting cell proliferation and in inhibiting drug-induced apoptosis.