Chaudhary Amit Kumar, Mondal Goutam, Kumar Virender, Kattel Krishna, Mahato Ram I
Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198, USA.
Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198, USA.
Cancer Lett. 2017 Aug 28;402:1-8. doi: 10.1016/j.canlet.2017.05.007. Epub 2017 May 20.
Treatment of pancreatic cancer with gemcitabine (GEM) is limited due to its rapid plasma metabolism and development of chemoresistance. MicroRNA (miRNA) regulates cancer stem cell (CSC) maintenance and induces chemoresistance in cancer cells. In this study, we observed differential downregulation of miR-205 (miR-205-5p) in human pancreatic cancer tissues and cells. Compared to GEM-sensitive MIA PaCa-2 cells, miR-205 was highly downregulated in GEM-resistant MIA PaCa-2R cells. Lentivirus-mediated overexpression of miR-205 inhibits MIA PaCa-2R cell proliferation after GEM-treatment. Further investigation confirmed that miR-205 alone significantly reduces the proliferation of CSCs and tumor growth in mouse models. However, miR-205 in combination with GEM was more efficient in reducing the proliferation of CSCs and 3D spheroids. Moreover, miR-205 overexpressing MIA PaCa-2R cells induced orthotopic tumor growth was significantly inhibited after intravenous administration of GEM-conjugated methoxy poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate)-graft-gemcitabine-graft-dodecanol (mPEG-b-PCC-g-GEM-g-DC) (mPEG-b-PCC-g-GEM-g-DC) polymeric micelles. Also, a reduction in CSCs, EMT and chemoresistance markers was observed in miR-205 overexpressing MIA PaCa-2R cells. Immunohistochemical analysis of orthotopic tumors showed a decrease in drug resistance protein caveolin-1 and cell proliferation marker Ki-67 in combination treatment. Overall, our findings suggest that miR-205 resensitizes GEM-resistant pancreatic cancer cells to GEM and acts as a tumor suppressor miRNA.
由于吉西他滨（GEM）在血浆中快速代谢以及化疗耐药性的产生，其对胰腺癌的治疗效果有限。微小RNA（miRNA）可调节癌症干细胞（CSC）的维持，并诱导癌细胞产生化疗耐药性。在本研究中，我们观察到miR-205（miR-205-5p）在人胰腺癌组织和细胞中存在差异性下调。与对GEM敏感的MIA PaCa-2细胞相比，miR-205在对GEM耐药的MIA PaCa-2R细胞中高度下调。慢病毒介导的miR-205过表达可抑制GEM处理后MIA PaCa-2R细胞的增殖。进一步研究证实，单独使用miR-205可显著降低小鼠模型中CSC的增殖和肿瘤生长。然而，miR-205与GEM联合使用在降低CSC和三维球体增殖方面更有效。此外，静脉注射吉西他滨共轭甲氧基聚（乙二醇）-嵌段-聚（2-甲基-2-羧基-碳酸丙烯酯）-接枝-吉西他滨-接枝-十二烷醇（mPEG-b-PCC-g-GEM-g-DC）（mPEG-b-PCC-g-GEM-g-DC）聚合物胶束后，过表达miR-205的MIA PaCa-2R细胞诱导的原位肿瘤生长受到显著抑制。同时，在过表达miR-205的MIA PaCa-2R细胞中观察到CSC、上皮-间质转化（EMT）和化疗耐药标志物减少。原位肿瘤的免疫组织化学分析显示，联合治疗后耐药蛋白小窝蛋白-1和细胞增殖标志物Ki-67减少。总体而言,我们的研究结果表明，miR-205使对GEM耐药的胰腺癌细胞对GEM重新敏感，并作为一种肿瘤抑制性miRNA发挥作用。
