Dataset Information

Effect of mTORC1 and 2 inhibition on myofibroblast global gene expression

ABSTRACT: Background: Mechanistic target of rapamycin (mTOR) is a nodal serine/threonine protein kinase critical for the control of fundamental cellular processes. Dysregulated mTOR signalling has been shown in cancer, COPD and idiopathic pulmonary fibrosis (IPF). mTOR forms the catalytic subunit of 2 protein complexes: mTORC1 and mTORC2 which differ in upstream inputs, downstream effects and sensitivity to the allosteric inhibitor rapamycin. Aim: To compare the effects of the mTORC1 inhibitor rapamycin with an ATP-competitive inhibitor of mTORC1/2, AZD8055, on TGFβ1 induced transcriptional responses during myofibroblast differentiation by RNA-Seq analysis. Methods: Primary human lung fibroblasts were treated with TGFβ1 for 24h to induce myofibroblast differentiation and extra cellular matrix (ECM) production in the presence of rapamycin or AZD8055. Fibroblasts were also treated with rapamycin or AZD8055 without TGFβ1. Total mRNA was analysed by RNA-Seq. Results: On a global transcriptomic level, TGFβ1 significantly affected the expression of ~4,200 genes by more than 1.5 fold, of which ~1,100 changes were reversed by pan-mTORC1/2 inhibition, while being insensitive to rapamycin. Only 15 gene changes were reversed exclusively by rapamycin. Analysis of the rapamycin-insensitive, mTOR sensitive myofibroblast transcriptome revealed ECM-receptor interaction, metabolism and actin cytoskeleton regulation as major affected pathways. Conclusions: Our data support the conclusion that therapeutic approaches aimed at interfering with TGFb1 induced myofibroblast differentiation and ECM production require dual mTOR1/2 inhibition and may, in part, explain the lack of clinical efficacy of everolimus in the context of IPF.

ORGANISM(S): Homo sapiens

PROVIDER: GSE102674 | GEO | 2019/05/01

REPOSITORIES: GEO

ACCESS DATA

Similar Datasets

Project description:Introduction: Mammalian target of rapamycin (mTOR) represents a key downstream intermediate for a myriad of oncogenic receptor tyrosine kinases. In the case of the insulin-like growth factor (IGF) pathway, the mTOR complex (mTORC1) mediates IGF-1 receptor (IGF-1R)-induced estrogen receptor alpha (ERÎ±) phosphorylation/activation and leads to increased proliferation and growth in breast cancer cells. As a result, the prevalence of mTOR inhibitors combined with hormonal therapy has increased in recent years. Conversely, activated mTORC1 provides negative feedback regulation of IGF signaling via insulin receptor substrate (IRS)-1/2 serine phosphorylation and subsequent proteasomal degradation. Thus, the IGF pathway may provide escape (e.g. de novo or acquired resistance) from mTORC1 inhibitors. It is therefore plausible that combined inhibition of mTORC1 and IGF-1R for select subsets of ER-positive breast cancer patients presents as a viable therapeutic option. Methods: Using hormone-sensitive breast cancer cells stably transfected with the aromatase gene (MCF-7/AC-1), works presented herein describe the in vitro and in vivo antitumor efficacy of the following compounds: dalotuzumab (DALO; âMK-0646â; anti-IGF-1R antibody), ridaforolimus (RIDA; âMK-8669â; mTORC1 small molecule inhibitor) and letrozole (âLETâ, aromatase inhibitor). Results: With the exception of MK-0646, all single agent and combination treatment arms effectively inhibited xenograft tumor growth, albeit to varying degrees. Correlative tissue analyses revealed MK-0646 alone and in combination with LET induced insulin receptor alpha A (InsR-A) isoform upregulation (both mRNA and protein expression), thereby further supporting a triple therapy approach. Conclusion: These data provide preclinical rationalization towards the combined triple therapy of LET plus MK-0646 plus MK-8669 as an efficacious anti-tumor strategy for ER-positive breast tumors. 46 samples, 28 days post treatment

Dataset Information

Effect of mTORC1 and 2 inhibition on myofibroblast global gene expression

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure