Yan Zhou1, Rui-hua Zhao2, Kuo-fu Tseng3, Kun-peng Li1, Zhi-gang Lu4, Yuan Liu4, Kun Han1, Zhi-hua Gan1, Shu-chen Lin1, Hai-yan Hu1, Da-liu Min1. 1. Department of Oncology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China. 2. Department of Oncology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China. 3. Department of Biophysics, Oregon State University, ALS-2139 Corvallis, OR 97330, USA. 4. Department of Hematology, Zhujiang Hospital Affiliated with Southern Medical University, Guangzhou 510282, China.
Abstract
AIM: Multi-drug resistance poses a critical bottleneck in chemotherapy. Given the up-regulation of mTOR pathway in many chemoresistant cancers, we examined whether sirolimus (rapamycin), a first generation mTOR inhibitor, might induce human osteosarcoma (OS) cell apoptosis and increase the sensitivity of OS cells to anticancer drugs in vitro. METHODS: Human OS cell line MG63/ADM was treated with sirolimus alone or in combination with doxorubicin (ADM), gemcitabine (GEM) or methotrexate (MTX). Cell proliferation and apoptosis were detected using CCK-8 assay and flow cytometry, respectively. MiRNAs in the cells were analyzed with miRNA microarray. The targets of miR-34b were determined based on TargetScan analysis and luciferase reporter assays. The expression of relevant mRNA and proteins was measured using qRT-PCR and Western blotting. MiR-34, PAK1 and ABCB1 levels in 40 tissue samples of OS patients were analyzed using qRT-PCR and in situ hybridization assays. RESULTS: Sirolimus (1-100 nmol/L) dose-dependently suppressed the cell proliferation (IC50=23.97 nmol/L) and induced apoptosis. Sirolimus (10 nmol/L) significantly sensitized the cells to anticancer drugs, leading to decreased IC50 values of ADM, GEM and MTX (from 25.48, 621.41 and 21.72 μmol/L to 4.93, 73.92 and 6.77 μmol/L, respectively). Treatment of with sirolimus increased miR-34b levels by a factor of 7.5 in the cells. Upregulation of miR-34b also induced apoptosis and increased the sensitivity of the cells to the anticancer drugs, whereas transfection with miR-34b-AMO, an inhibitor of miR-34b, reversed the anti-proliferation effect of sirolimus. Two key regulators of cell cycle, apoptosis and multiple drug resistance, PAK1 and ABCB1, were demonstrated to be the direct targets of miR-34b. In 40 tissue samples of OS patients, significantly higher miR-34 ISH score and lower PAK5 and ABCB1 scores were detected in the chemo-sensitive group. CONCLUSION: Sirolimus increases the sensitivity of human OS cells to anticancer drugs in vitro by up-regulating miR-34b interacting with PAK1 and ABCB1. A low miR-34 level is an indicator of poor prognosis in OS patients.
AIM: Multi-drug resistance poses a critical bottleneck in chemotherapy. Given the up-regulation of mTOR pathway in many chemoresistant cancers, we examined whether sirolimus (rapamycin), a first generation mTOR inhibitor, might induce humanosteosarcoma (OS) cell apoptosis and increase the sensitivity of OS cells to anticancer drugs in vitro. METHODS:Human OS cell line MG63/ADM was treated with sirolimus alone or in combination with doxorubicin (ADM), gemcitabine (GEM) or methotrexate (MTX). Cell proliferation and apoptosis were detected using CCK-8 assay and flow cytometry, respectively. MiRNAs in the cells were analyzed with miRNA microarray. The targets of miR-34b were determined based on TargetScan analysis and luciferase reporter assays. The expression of relevant mRNA and proteins was measured using qRT-PCR and Western blotting. MiR-34, PAK1 and ABCB1 levels in 40 tissue samples of OS patients were analyzed using qRT-PCR and in situ hybridization assays. RESULTS:Sirolimus (1-100 nmol/L) dose-dependently suppressed the cell proliferation (IC50=23.97 nmol/L) and induced apoptosis. Sirolimus (10 nmol/L) significantly sensitized the cells to anticancer drugs, leading to decreased IC50 values of ADM, GEM and MTX (from 25.48, 621.41 and 21.72 μmol/L to 4.93, 73.92 and 6.77 μmol/L, respectively). Treatment of with sirolimus increased miR-34b levels by a factor of 7.5 in the cells. Upregulation of miR-34b also induced apoptosis and increased the sensitivity of the cells to the anticancer drugs, whereas transfection with miR-34b-AMO, an inhibitor of miR-34b, reversed the anti-proliferation effect of sirolimus. Two key regulators of cell cycle, apoptosis and multiple drug resistance, PAK1 and ABCB1, were demonstrated to be the direct targets of miR-34b. In 40 tissue samples of OS patients, significantly higher miR-34 ISH score and lower PAK5 and ABCB1 scores were detected in the chemo-sensitive group. CONCLUSION:Sirolimus increases the sensitivity of human OS cells to anticancer drugs in vitro by up-regulating miR-34b interacting with PAK1 and ABCB1. A low miR-34 level is an indicator of poor prognosis in OS patients.
Authors: Melissa C Paoloni; Christina Mazcko; Elizabeth Fox; Timothy Fan; Susan Lana; William Kisseberth; David M Vail; Kaylee Nuckolls; Tanasa Osborne; Samuel Yalkowsy; Daniel Gustafson; Yunkai Yu; Liang Cao; Chand Khanna Journal: PLoS One Date: 2010-06-08 Impact factor: 3.240
Authors: G M Viera; K B Salomao; G R de Sousa; M Baroni; L E A Delsin; J A Pezuk; M S Brassesco Journal: Clin Transl Oncol Date: 2019-04-04 Impact factor: 3.405