Glucose-6-phosphate dehydrogenase blockade potentiates tyrosine kinase inhibitor effect on breast cancer cells through autophagy perturbation

Mele, L., La Noce, M., Paino, F., Regad, T. ORCID: 0000-0003-4028-6368, Wagner, S., Liccardo, D., Papaccio, G., Lombardi, A., Caraglia, M., Tirino, V., Desiderio, V. and Papaccio, F., 2019. Glucose-6-phosphate dehydrogenase blockade potentiates tyrosine kinase inhibitor effect on breast cancer cells through autophagy perturbation. Journal of Experimental & Clinical Cancer Research, 38: 160. ISSN 1756-9966

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Abstract

Background:

Glucose-6-phospate dehydrogenase (G6PD) is the limiting enzyme of the pentose phosphate pathway (PPP) correlated to cancer progression and drug resistance. We previously showed that G6PD inhibition leads to Endoplasmic Reticulum (ER) stress often associated to autophagy deregulation. The latter can be induced by target-based agents such as Lapatinib, an anti-HER2 tyrosine kinase inhibitor (TKI) largely used in breast cancer treatment.

Methods:

Here we investigate whether G6PD inhibition causes autophagy alteration, which can potentiate Lapatinib effect on cancer cells. Immunofluorescence and flow cytometry for LC3B and lysosomes tracker were used to study autophagy in cells treated with lapatinib and/or G6PD inhibitors (polydatin). Immunoblots for LC3B and p62 were performed to confirm autophagy flux analyses together with puncta and colocalization studies. We generated a cell line overexpressing G6PD and performed synergism studies on cell growth inhibition induced by Lapatinib and Polydatin using the median effect by Chou-Talay. Synergism studies were additionally validated with apoptosis analysis by annexin V/PI staining in the presence or absence of autophagy blockers.

Results:

We found that the inhibition of G6PD induced endoplasmic reticulum stress, which was responsible for the deregulation of autophagy flux. Indeed, G6PD blockade caused a consistent increase of autophagosomes formation independently from mTOR status. Cells engineered to overexpress G6PD became resilient to autophagy and resistant to lapatinib. On the other hand, G6PD inhibition synergistically increased lapatinib-induced cytotoxic effect on cancer cells, while autophagy blockade abolished this effect. Finally, in silico studies showed a significant correlation between G6PD expression and tumour relapse/resistance in patients.

Conclusions:

These results point out that autophagy and PPP are crucial players in TKI resistance, and highlight a peculiar vulnerability of breast cancer cells, where impairment of metabolic pathways and autophagy could be used to reinforce TKI efficacy in cancer treatment.

Item Type: Journal article
Publication Title: Journal of Experimental & Clinical Cancer Research
Creators: Mele, L., La Noce, M., Paino, F., Regad, T., Wagner, S., Liccardo, D., Papaccio, G., Lombardi, A., Caraglia, M., Tirino, V., Desiderio, V. and Papaccio, F.
Publisher: BioMed Central
Date: 12 April 2019
Volume: 38
ISSN: 1756-9966
Identifiers:
NumberType
10.1186/s13046-019-1164-5DOI
Rights: © The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
Divisions: Schools > School of Science and Technology
Depositing User: Jill Tomkinson
Date Added: 01 May 2019 09:37
Last Modified: 01 May 2019 09:37
URI: http://irep.ntu.ac.uk/id/eprint/36364

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