Co-occurring KRAS mutation/LKB1 loss in non-small cell lung cancer cells results in enhanced metabolic activity susceptible to caloric restriction: an in vitro integrated multilevel approach

Elisa Caiola,Roberta Pastorelli,Massimo Broggini,Mirko Marabese,Francesca Falcetta,Laura Brunelli,Marina C Garassino,Silvia Giordano

doi:10.1186/s13046-018-0954-5

Abstract

BackgroundNon–small-cell lung cancer (NSCLC) is a heterogeneous disease, with multiple different oncogenic mutations. Approximately 25–30% of NSCLC patients present KRAS mutations, which confer poor prognosis and high risk of tumor recurrence. About half of NSCLCs with activating KRAS lesions also have deletions or inactivating mutations in the serine/threonine kinase 11 (LKB1) gene. Loss of LKB1 on a KRAS-mutant background may represent a significant source of heterogeneity contributing to poor response to therapy.MethodsHere, we employed an integrated multilevel proteomics, metabolomics and functional in-vitro approach in NSCLC H1299 isogenic cells to define their metabolic state associated with the presence of different genetic background. Protein levels were obtained by label free and single reaction monitoring (SRM)-based proteomics. The metabolic state was studied coupling targeted and untargeted mass spectrometry (MS) strategy. In vitro metabolic dependencies were evaluated using 2-deoxy glucose (2-DG) treatment or glucose/glutamine nutrient limitation.ResultsHere we demonstrate that co-occurring KRAS mutation/LKB1 loss in NSCLC cells allowed efficient exploitation of glycolysis and oxidative phosphorylation, when compared to cells with each single oncologic genotype. The enhanced metabolic activity rendered the viability of cells with both genetic lesions susceptible towards nutrient limitation.ConclusionsCo-occurrence of KRAS mutation and LKB1 loss in NSCLC cells induced an enhanced metabolic activity mirrored by a growth rate vulnerability under limited nutrient conditions relative to cells with the single oncogenetic lesions. Our results hint at the possibility that energy stress induced by calorie restriction regimens may sensitize NSCLCs with these co-occurring lesions to cytotoxic chemotherapy.

Highlights

Non–small-cell lung cancer (NSCLC) is a heterogeneous disease, with multiple different oncogenic mutations
Growth properties of cells with different genetic lesions From our well-characterized NCI-H1299 derived clones expressing KRASWT or KRASG12C [35, 36], we generated two clones characterized by LKB1 loss taking advantage of the CRISPR/Cas9 technology, which allows locus-specific gene editing
We previously demonstrated that metabolic traits observed in KRAS-mutated NSCLC cells in culture translate into a murine model of human NSCLC cell xenografts [54]

Summary

Introduction

Non–small-cell lung cancer (NSCLC) is a heterogeneous disease, with multiple different oncogenic mutations. About half of NSCLCs with activating KRAS lesions have deletions or inactivating mutations in the serine/threonine kinase 11 (LKB1) gene. Non–small cell lung cancer (NSCLC) is a heterogeneous disease, with multiple different oncogenic driver mutations representing potential therapeutic targets [1,2,3]. Half of NSCLC patients with activating KRAS lesions have deletions or inactivating mutations in the serine/threonine kinase 11 gene (LKB1/STK11) [17,18,19,20]. LKB1 is a tumor suppressor that phosphorylates and activates several downstream targets to regulate signal transduction, energy sensing and cell polarity [21, 22] It has a pivotal role in metabolic reprogramming and nutrient sensing, mainly through its ability to activate AMP-activated protein kinase (AMPK) [19, 23,24,25,26]. Inactivated LKB1 is found in a wide range of human cancers including those of the pancreas, cervix and lung [27, 28]

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