Yun Chen1, Huang-Wen Tsai2, Ya-Hui Tsai3, Sheng-Hong Tseng4. 1. Department of Surgery, Far Eastern Memorial Hospital, Pan-Chiao, New Taipei, Taiwan; Graduate Institute of Medicine and Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li, Taoyuan, Taiwan. 2. Department of Surgery, Far Eastern Memorial Hospital, Pan-Chiao, New Taipei, Taiwan. 3. Department of Surgery, Far Eastern Memorial Hospital, Pan-Chiao, New Taipei, Taiwan; Graduate Institute of Medicine and Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li, Taoyuan, Taiwan. Electronic address: yahuitsi@gmail.com. 4. Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan. Electronic address: shenghongtseng@gmail.com.
Abstract
BACKGROUND: The phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is closely related to oncogenesis. PI3K/mTOR inhibitors are considered capable of counteracting the feedback mechanisms within the pathway. In this study, we investigated the antitumor effects of VS-5584, an orally administered PI3K/mTOR dual inhibitor, on neuroblastomas. METHODS: The effects of VS-5584 on proliferation, cell cycle distribution, and related signaling molecules were examined in neuroblastoma cells using the (3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide)-based colorimetric assay, flow cytometry, and western blotting, respectively. Nude mice were subcutaneously inoculated with human neuroblastoma cells, followed by VS-5584 treatment for two weeks. Tumor growth was tracked and tumor tissues were subjected to immunohistochemical investigations. RESULTS: In neuroblastoma cells, VS-5584 significantly inhibited proliferation and induced G0/G1 cell cycle arrest. Additionally, VS-5584 decreased the expression of phospho-S6 kinase 1 (p-S6K1), p-retinoblastoma protein, p-cyclin-dependent kinase 2, and cyclin E1, and increased the expression of p21 and p27 in neuroblastoma cells. In mice, VS-5584 significantly suppressed tumor growth in neuroblastomas and downregulated the expression of p-mTOR and p-S6K1 in tumor tissues. CONCLUSIONS: VS-5584 blocks the PI3K/mTOR pathway, induces a G0/G1 cell cycle arrest, and exerts antitumor effects on neuroblastomas both in vitro and in vivo.
BACKGROUND: The phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is closely related to oncogenesis. PI3K/mTOR inhibitors are considered capable of counteracting the feedback mechanisms within the pathway. In this study, we investigated the antitumor effects of VS-5584, an orally administered PI3K/mTOR dual inhibitor, on neuroblastomas. METHODS: The effects of VS-5584 on proliferation, cell cycle distribution, and related signaling molecules were examined in neuroblastoma cells using the (3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide)-based colorimetric assay, flow cytometry, and western blotting, respectively. Nude mice were subcutaneously inoculated with humanneuroblastoma cells, followed by VS-5584 treatment for two weeks. Tumor growth was tracked and tumor tissues were subjected to immunohistochemical investigations. RESULTS: In neuroblastoma cells, VS-5584 significantly inhibited proliferation and induced G0/G1 cell cycle arrest. Additionally, VS-5584 decreased the expression of phospho-S6 kinase 1 (p-S6K1), p-retinoblastoma protein, p-cyclin-dependent kinase 2, and cyclin E1, and increased the expression of p21 and p27 in neuroblastoma cells. In mice, VS-5584 significantly suppressed tumor growth in neuroblastomas and downregulated the expression of p-mTOR and p-S6K1 in tumor tissues. CONCLUSIONS:VS-5584 blocks the PI3K/mTOR pathway, induces a G0/G1 cell cycle arrest, and exerts antitumor effects on neuroblastomas both in vitro and in vivo.