Research Paper Volume 9, Issue 11 pp 2352—2375
Targeted elimination of senescent Ras-transformed cells by suppression of MEK/ERK pathway
- 1 Institute of Cytology, Russian Academy of Sciences, St-Petersburg, Russia
received: September 27, 2017 ; accepted: November 4, 2017 ; published: November 14, 2017 ;https://doi.org/10.18632/aging.101325
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Copyright: Kochetkova et al. This is an open‐access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
The Ras-Raf-MEK-ERK pathway plays a central role in tumorigenesis and is a target for anticancer therapy. The successful strategy based on the activation of cell death in Ras-expressing cells is associated with the suppression of kinases involved in Ras pathway. However, activation of cytoprotective autophagy overcomes antiproliferative effect of the inhibitors and develops drug resistance. We studied whether cellular senescence induced by HDAC inhibitor sodium butyrate in E1a+cHa-Ras-transformed rat embryo fibroblasts (ERas) and A549 human Ki-Ras mutated lung adenocarcinoma cells would enhance the tumor suppressor effect of MEK/ERK inhibition. Treatment of control ERas cells with PD0325901 for 24 h results in mitochondria damage and apoptotic death of a part of cellular population. However, the activation of AMPK-dependent autophagy overcomes pro-apoptotic effects of MEK/ERK inhibitor and results in restoration of the mitochondria and rescue of viability. Senescent ERas cells do not develop cytoprotective autophagy upon inhibition of MEK/ERK pathway due to spatial dissociation of lysosomes and autophagosomes in the senescent cells. Senescent cells are unable to form the autophagolysosomes and to remove the damaged mitochondria resulting in apoptotic death. Our data show that suppression of MEK/ERK pathway in senescent cells provides a new strategy for elimination of Ras-expressing cells.
NaBut: sodium butyrate; TEM: transmission electron microscopy; MOMP: mitochondrial outer membrane permeabilization; mTOR: mammalian Target of Rapamycin; mTORC1: mammalian Target of Rapamycin Complex 1; ERK: extracellular signal-regulated kinase; MEK: mitogen-activated protein kinase kinase; SQSTM1: Sequestosome 1; LC3: microtubule-associated protein light chain 3; DMEM: Dulbecco’s modified Eagle medium; FBS: fetal bovine serum; MTT: (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; TMRM: Tetramethylrhodamine, Methyl Ester, Perchlorate; SDS: sodium dodecyl sulphate; DMSO: dimethyl sulfoxide; BSA: bovine serum albumin; DAPI: 4,6-diamidino-2-phenylindole; TBS: Tris-buffered solution; CHAPS: 3-[(3-Cholamidopropyl) dimethylammonio]-1-propanesulfonate hydrate.