title: Knockdown of AKT2 expression by RNA interference inhibits proliferation, enhances apoptosis, and increases chemosensitivity to the anticancer drug VM-26 in U87 glioma cells.
abstract: The AKT2 kinase (protein kinas Bβ) is frequently overexpressed in malignant gliomas. In this study, the human glioblastoma cell line U87 was stably transfected with a lentivirus vector expressing a short hairpin RNA (shRNA) targeting AKT2. Knockdown of AKT2 by the shRNA inhibited U87 cell proliferation and increased the rate of apoptosis. Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blot analysis revealed that cells stably underexpressing AKT2 showed lower expression of the anti-apoptotic protein B-cell lymphoma-2 (Bcl-2) and enhanced expression of the apoptosis effector caspase-3 compared to U87 cells stably transfected with a control vector. Furthermore, expression levels of AKT2 were correlated with the IC50 of the antitumor drug VM-26 (teniposide); the VM-26 IC50 was reduced from 6.46±0.42μg/ml in control glioma cells to 1.15±0.22μg/ml in U87 cells underexpressing AKT2. Combined AKT2 knockdown and VM-26 treatment inhibited cell proliferation in vitro more effectively than either treatment alone. Knockdown of AKT2 expression was associated with decreased expression of the multidrug resistance-associated protein 1 (MRP1) without affecting MRP1 mRNA expression. However, the mRNA and protein levels of MDR1 (p-glycoprotein) were unaffected by AKT2 knockdown. These results indicate that inhibition of AKT2 expression may be an effective means for overcoming AKT2-associated chemoresistance in human malignant glioma cells and may represent a potential gene-targeting approach to treat glioma.
authors: Department of Neurosurgery, Changzheng Hospital, Second Military Medical University, No. 415 FengYang Road, Shanghai 200003, People's Republic of China.
authors: Yong
authors: Y
authors: Cui
authors: Qi
authors: Q
authors: Wang
authors: Junyu
authors: J
authors: Wang
authors: Yan
authors: Y
authors: Dong
authors: Chun
authors: C
authors: Luo
authors: Guohan
authors: G
authors: Hu
authors: Yicheng
authors: Y
authors: Lu
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D005910:Glioma / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics* / Q000378:metabolism; D034622:RNA Interference; D013713:Teniposide / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D013713:Teniposide; D051057:Proto-Oncogene Proteins c-akt