Hypoxia-Induced Cisplatin Resistance in Non-Small Cell Lung Cancer Cells Is Mediated by HIF-1α and Mutant p53 and Can Be Overcome by Induction of Oxidative Stress.

Christophe Deben,Patrick Pauwels,Jolien Van Den Bossche,Christian Rolfo,Vanessa Deschoolmeester,Filip Lardon,Evelien Smits,An Wouters,Marc Peeters,Julie Jacobs,Jorrit De Waele

doi:10.3390/cancers10040126

Christophe Deben, Patrick Pauwels + Show 9 more

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https://doi.org/10.3390/cancers10040126

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Journal: Cancers	Publication Date: Apr 21, 2018
Citations: 46	License type: CC BY 4.0

Affiliation: University of Antwerp, Antwerp University Hospital

Abstract

The compound APR-246 (PRIMA-1MET) is a known reactivator of (mutant) p53 and inducer of oxidative stress which can sensitize cancer cells to platinum-based chemotherapeutics. However, the effect of a hypoxic tumor environment has been largely overlooked in this interaction. This study focusses on the role of hypoxia-inducible factor-1α (HIF-1α) and the p53 tumor suppressor protein in hypoxia-induced cisplatin resistance in non-small cell lung cancer (NSCLC) cells and the potential of APR-246 to overcome this resistance. We observed that hypoxia-induced cisplatin resistance only occurred in the p53 mutant NCI-H2228Q331* cell line, and not in the wild type A549 and mutant NCI-H1975R273H cell lines. Cisplatin reduced HIF-1α protein levels in NCI-H2228Q331* cells, leading to a shift in expression from HIF-1α-dependent to p53-dependent transcription targets under hypoxia. APR-246 was able to overcome hypoxia-induced cisplatin resistance in NCI-H2228Q331* cells in a synergistic manner without affecting mutant p53Q331* transcriptional activity, but significantly depleting total glutathione levels more efficiently under hypoxic conditions. Synergism was dependent on the presence of mutant p53Q331* and the induction of reactive oxygen species, with depletion of one or the other leading to loss of synergism. Our data further support the rationale of combining APR-246 with cisplatin in NSCLC, since their synergistic interaction is retained or enforced under hypoxic conditions in the presence of mutant p53.

Highlights

Lung cancer remains the leading cause of cancer-related deaths worldwide and is characterized by a poor overall survival
We focused on hypoxia-induced cisplatin resistance, on the interaction between p53 and hypoxia-inducible factor-1α (HIF-1α), to restore treatment response in a panel of non-small cell lung cancer (NSCLC) cell lines with different p53 status using the compound APR-246 (PRIMA-1MET )
We show that hypoxia-induced cisplatin resistance only occurred when cisplatin affected Hypoxia-inducible factor (HIF)-1α protein levels

Summary

Introduction

Lung cancer remains the leading cause of cancer-related deaths worldwide and is characterized by a poor overall survival. HIF-1α has been shown to regulate p53 tumor suppressor protein levels in response to hypoxia, while on the other hand p53 can negatively regulate HIF-1α protein levels This complex interaction is strongly dependent on oxygen levels, the duration of hypoxic exposure, and even cell type, as proposed by the model of Sermeus and Michiels [6]. Numerous studies have shown that under mild hypoxic conditions, p53 protein levels are decreased, thereby protecting the cells against apoptosis and promoting cell survival as an adaptive mechanism to the hypoxic environment, a process regulated by HIF-1α. High levels of HIF-1α have been reported to negatively influence the response to cisplatin treatment in various tumor types, including lung cancer [9,10,11]. It has been shown that a positive selection pressure exists for p53-deficient (mutant) cells in hypoxic tumor regions, allowing clonal expansion of cells with decreased apoptotic potential, chemoresistant properties, and high metastatic capabilities [6,7,12,13]

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