Department of General Surgery, Chinese Academy of Medical Sciences, Medical College Hospital, Peking Union Medical College, Beijing, P.R. China.
Arch Med Res. 2011 Jan;42(1):8-14. doi: 10.1016/j.arcmed.2011.01.006.
Bcl-2 was previously shown to be associated with apoptosis and chemoresistance and carry multiple regulating pathways. However, the roles and mechanisms of miRNA (miR)-21 in regulation of Bcl-2 in pancreatic cancer remain to be elucidated. The aim of this study was to explore the regulation of Bcl-2 expression by miR-21 and its impact on apoptosis, chemoresistance and growth of pancreatic cancer cells using a pancreatic cancer cell line, MIA PaCa-2.
miR-21 mimics and inhibitor were transfected to MIA PaCa-2 pancreatic cancer cells, respectively. Alteration in Bcl-2/Bax expression was subsequently evaluated. Then, luciferase activity was observed after miR-21 mimics and pRL-TK plasmids containing wild-type and mutant 3'UTRs of Bcl-2 mRNA were co-transfected. Finally, apoptosis, chemosensitivity to gemcitabine and cell proliferation were evaluated.
Upregulation of Bcl-2 expression was detected in cells transfected with miR-21 mimics, accompanied by downregulated Bax expression, less apoptosis, lower caspase-3 activity, decreased chemosensitivity to gemcitabine and increased proliferation compared with the control cells. Cells transfected with miR-21 inhibitor revealed an opposite trend. There was a significant increase in luciferase activity in the cells transfected with the wild-type pRL-TK plasmid, in contrast to those transfected with the mutant one, indicating that miR-21 promotes Bcl-2 expression by binding directly to the 3'UTR of Bcl-2 mRNA.
Upregulation of Bcl-2 directly induced by miR-21 is associated with apoptosis, chemoresistance and proliferation of MIA PaCa-2 pancreatic cancer cells.
Bcl-2 先前被证明与细胞凋亡和化学耐药性有关，并携带多种调节途径。然而，miRNA（miR）-21 在调节胰腺癌细胞中 Bcl-2 中的作用和机制仍有待阐明。本研究旨在通过胰腺癌细胞系 MIA PaCa-2 探讨 miR-21 对 Bcl-2 表达的调节及其对胰腺癌细胞凋亡、化学耐药性和生长的影响。
分别转染 miR-21 模拟物和抑制剂至 MIA PaCa-2 胰腺癌细胞，随后评估 Bcl-2/Bax 表达的变化。然后，观察 miR-21 模拟物和含有 Bcl-2 mRNA 野生型和突变 3'UTR 的 pRL-TK 质粒共转染后荧光素酶活性的变化。最后，评估细胞凋亡、吉西他滨的化学敏感性和细胞增殖。
转染 miR-21 模拟物的细胞中检测到 Bcl-2 表达上调，同时 Bax 表达下调，凋亡减少，caspase-3 活性降低，对吉西他滨的化学敏感性降低，增殖增加，与对照细胞相比。转染 miR-21 抑制剂的细胞则呈现相反的趋势。转染野生型 pRL-TK 质粒的细胞中荧光素酶活性显著增加，而转染突变型的细胞则没有，这表明 miR-21 通过直接结合 Bcl-2 mRNA 的 3'UTR 促进 Bcl-2 表达。
miR-21 直接上调 Bcl-2 与 MIA PaCa-2 胰腺癌细胞的凋亡、化学耐药性和增殖有关。
