@article{71bad4c0ba15439d84fe85e03897b044,
title = "Targeting BCR-ABL-independent TKI resistance in chronic myeloid leukemia by mTOR and autophagy inhibition",
abstract = "Background: Imatinib and second-generation tyrosine kinase inhibitors (TKIs) nilotinib and dasatinib have statistically significantly improved the life expectancy of chronic myeloid leukemia (CML) patients; however, resistance to TKIs remains a major clinical challenge. Although ponatinib, a third-generation TKI, improves outcomes for patients with BCR-ABL-dependent mechanisms of resistance, including the T315I mutation, a proportion of patients may have or develop BCR-ABL-independent resistance and fail ponatinib treatment. By modeling ponatinib resistance and testing samples from these CML patients, it is hoped that an alternative drug target can be identified and inhibited with a novel compound. Methods: Two CML cell lines with acquired BCR-ABL-independent resistance were generated following culture in ponatinib. RNA sequencing and gene ontology (GO) enrichment were used to detect aberrant transcriptional response in ponatinib-resistant cells. A validated oncogene drug library was used to identify US Food and Drug Administration-approved drugs with activity against TKI-resistant cells. Validation was performed using bone marrow (BM)-derived cells from TKI-resistant patients (n = 4) and a human xenograft mouse model (n = 4-6 mice per group). All statistical tests were two-sided. Results: We show that ponatinib-resistant CML cells can acquire BCR-ABL-independent resistance mediated through alternative activation of mTOR. Following transcriptomic analysis and drug screening, we highlight mTOR inhibition as an alternative therapeutic approach in TKI-resistant CML cells. Additionally, we show that catalytic mTOR inhibitors induce autophagy and demonstrate that genetic or pharmacological inhibition of autophagy sensitizes ponatinib-resistant CML cells to death induced by mTOR inhibition in vitro (% number of colonies of control[SD], NVP-BEZ235 vs NVP-BEZ235+HCQ: 45.0[17.9]% vs 24.0[8.4]%, P = 002) and in vivo (median survival of NVP-BEZ235-vs NVP-BEZ235+HCQ-treated mice: 38.5 days vs 47.0 days, P = 04). Conclusion: Combined mTOR and autophagy inhibition may provide an attractive approach to target BCR-ABL-independent mechanism of resistance.",
author = "Rebecca Mitchell and Hopcroft, {Lisa E.M.} and Pablo Baquero and Allan, {Elaine K.} and Kay Hewit and Daniel James and Graham Hamilton and Arunima Mukhopadhyay and Jim O'Prey and Alan Hair and Melo, {Junia V.} and Edmond Chan and Ryan, {Kevin M.} and V{\'e}ronique Maguer-Satta and Druker, {Brian J.} and Clark, {Richard E.} and Subir Mitra and Pawel Herzyk and Nicolini, {Franck E.} and Paolo Salomoni and Emma Shanks and Bruno Calabretta and Holyoake, {Tessa L.} and Helgason, {G. Vignir}",
note = "Funding Information: Centre (C596/A18076) and the BSU facilities at the Cancer Research UK Beatson Institute (C596/A17196), Scottish Universities Life Science Alliance (MSD23_G_Holyoake-Chan), Scottish National Blood Transfusion Service, Cancer Research UK programme funding (C11074/A11008), the Howat Foundation and Friends of Paul O{\textquoteright}Gorman (flow cytometry support). GVH is a Kay Kendall Leukaemia Fund (KKLF) Intermediate Research Fellow (KKL698)/Leadership Fellow/John Goldman Fellow. LH is a KKLF Intermediate Research Fellow (KKL1148)/John Goldman Fellow. BC is supported, in part, by National Cancer Institute grant CA95111. PS is funded by the Brain Tumour Charity, Cancer Research UK (CRUK) and Association for International Cancer Research (AICR) and is supported by the National Institute for Health Research University College London Hospitals Biomedical Research Centre. BJD is funded by the Howard Hughes Medical Institute and National Institutes of Health grant R37CA065823. Funding Information: TLH has previously received research support from Bristol-Myers Squibb and Novartis. FEN is a consultant for Novartis, ARIAD, and Pfizer, has received research grants from Novartis, Funding Information: The next-generation sequencing was performed by Glasgow Polyomics and supported by the Wellcome Trust (105614/Z/14/ Z). Firefly luciferase vector (pLenti CMV Puro LUC) was kindly provided by Mike Olson. mRFP-GFP-LC3 was kindly provided by Tamotsu Yoshimori. We thank A. Michie and K. Dunn for assisting with in vivo work (MRC/AstraZeneca project grants: Ref: MR/ K014854/1), the National Health Service GGC Bio-repository Unit, Paolo Gallipoli and Susan Rhodes for collection of normal and TKI-resistant patient samples, UK Haematologists, and patients with chronic myeloid leukemia. We thank Bristol-Myers Squibb and ARIAD Pharmaceuticals for providing dasatinib and ponatinib, respectively. Funding Information: This work was supported by Medical Research Council (G0600782 and G0900882, CHOICES, ISCRTN No. 61568166), the Kay Kendall Leukaemia Fund (KKL404 and KKL501), Leuka, Glasgow Experimental Cancer Medicine Centre, which is funded by Cancer Research UK and the Chief Scientist{\textquoteright}s Office (Scotland), Cancer Research UK Glasgow Publisher Copyright: {\textcopyright} The Author 2017. Published by Oxford University Press.",
year = "2018",
month = may,
day = "1",
doi = "10.1093/jnci/djx236",
language = "English (US)",
volume = "110",
pages = "467--478",
journal = "Journal of the National Cancer Institute",
issn = "0027-8874",
publisher = "Oxford University Press",
number = "5",
}