In non-small-cell lung cancer (NSCLC), one-fifth of patients have KRAS mutations, which are considered a negative predictive factor to first-line therapy. Evidence is emerging that not all KRAS mutations have the same biological activities and possible remodeling of cell metabolism by KRAS activation might complicate the scenario. An open question is whether different KRAS mutations at codon-12 affect cellular metabolism differently with possible implications for different responses to cancer treatments.We applied an explorative mass spectrometry-based untargeted metabolomics strategy to characterize the largest possible number of metabolites that might distinguish isogenic NSCLC cells overexpressing mutated forms of KRAS at codon-12 (G12C, G12D, G12V) and the wild-type. The glutamine deprivation assay and real-time PCR were used to confirm the involvement of some of the metabolic pathways highlighted.Cell clones indicated distinct metabolomic profiles in KRAS wild-type and mutants. Clones harboring different KRAS mutations at codon-12 also had different metabolic remodeling, such as a different redox buffering system and different glutamine-dependency not driven by the transcriptional state of enzymes involved in glutaminolysis.These findings indicate that KRAS mutations at codon-12 are associated with different metabolomic profiles that might affect the responses to cancer treatments.

KRAS mutations seem to indicate a poor outcome in Non-Small-Cell Lung Cancer (NSCLC) but such evidence is still debated. The aim of this planned ancillary study within the TAILOR trial was to assess the prognostic value of KRAS mutations in advanced NSCLC patients treated with platinum-based first-line chemotherapy. Patients (N = 540), enrolled in the study in 52 Italian hospitals, were centrally genotyped twice in two independent laboratories for EGFR and KRAS mutational status.Of these, 247 patients were eligible and included in the present study. The primary endpoint was overall survival (OS) according to KRAS mutational status in patients harboring EGFR wild-type.Sixty (24.3%) out of 247 patients harbored KRAS mutations. Median OS was 14.3 months and 10.6 months in wild-type and mutated KRAS patients, respectively (unadjusted Hazard Ratio [HR]=1.41, 95%Confidence Interval [CI]: 1.03-1.94 P = 0.032; adjusted HR=1.39, 95%CI: 1.00-1.94 P = 0.050). This study, with all consecutive patients genotyped, indicates that the presence of KRAS mutations has a mild negative impact on OS in advanced NSCLC patient treated with a first-line platinum-containing regimen. Trial Registration: clinicaltrials.gov identifier NCT00637910

LKB1 mutations, especially when combined with KRAS mutations, may define a specific and more aggressive NSCLC subtype. Metformin synergizes with cisplatin against KRAS/LKB1 co-mutated tumors, and may prevent or delay the onset of resistance to cisplatin by targeting CD133 cancer stem cells. This study lays the foundations for combining metformin with standard platinum-based chemotherapy in the treatment of KRAS/LKB1 co-mutated NSCLC.

KRAS mutations in NSCLC are supposed to indicate a poor prognosis and poor response to anticancer treatments but this feature lacks a mechanistic basis so far. In tumors, KRAS was found to be mutated mostly at codons 12 and 13 and a pool of mutations differing in the base alteration and the amino acid substitution have been described. The different KRAS mutations may differently impact on cancerogenesis and drug sensitivity. On this basis, we hypothesized that a different KRAS mutational status in NSCLC patients determines a different profile in the tumor response to treatments. In this paper, isogenic NSCLC cell clones expressing mutated forms of KRAS were used to determine the response to cisplatin, the main drug used in the clinic against NSCLC. Cells expressing the KRAS(G12C) mutation were found to be less sensitive to treatment both in vitro and in vivo. Systematic analysis of drug uptake, DNA adduct formation and DNA damage responses implicated in cisplatin adducts removal revealed that the KRAS(G12C) mutation might be particular because it stimulates Base Excision Repair to rapidly remove platinum from DNA even before the formation of cross-links.The presented results suggest a different pattern of sensitivity/resistance to cisplatin depending on the KRAS mutational status and these data might provide proof of principle for further investigations on the role of the KRAS status as a predictor of NSCLC response.

Oncogenes induce metabolic reprogramming on cancer cells. Recently, G12C KRAS mutation in isogenic NSCLC cell line has been shown to be a key player in promoting metabolic rewiring mainly through the regulation of glutamine metabolism to fuel growth and proliferation. Even though cell lines possessing many of the genetic backgrounds of the primary cancer they derive from could be a valuable pre-clinical model, they do not have the additional complexity present in the whole tumor that impact metabolism. This preliminary study is aimed to explore how cancer cell metabolism in culture might recapitulate the metabolic alterations present in vivo. Our result highlighted that the gross metabolic changes observed in G12C KRAS mutant cells growing in culture were also maintained in the derived xenograft model, suggesting that a simple in vitro cell model can give important insights into the metabolic alterations induced by cancer. This is of relevance for guiding effective targeting of those metabolic traits that underlie tumor progression and anticancer treatment responses.

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.Electronic supplementary materialThe online version of this article (10.1186/s13046-018-0954-5) contains supplementary material, which is available to authorized users.

The RAS/RAF/MEK signaling pathway plays a central role in mediating both proliferation and survival of cancer cells. These proteins are a group of serine/threonine kinases activated in response to a variety of extracellular stimuli and mediate signal transduction from the cell surface towards both nuclear and cytosolic targets. In combination with several other signaling pathways, they can differentially alter phosphorylation status of the transcription factors. A controlled regulation of these cascades is involved in cell proliferation and differentiation, whereas an unregulated activation of these kinases can result in oncogenesis. Dysregulation of the RAS/RAF/MEK pathway has been detected in more than 30% of human tumors, however mutations in the MEK1 and MEK2 genes are seldom, so that hyperactivation of MEK1/2 usually results from gain-of-function mutations in RAS and/or B-RAF. In addition, alteration of the pathways is often associated with drug resistance in the clinic, such as the case of K-RAS mutant expressing tumors. Since RAS protein is a difficult target, alternative ways altering post-translational modifications using farnesyl transferase inhibitors have been adopted. Drug discovery programs have therefore largely focused on B-RAF and MEK. In this review we will discuss the most promising strategies developed to target these kinases and the most recent inhibitors facing the preclinical and clinical setting, also considering their structure-activity relationship (SAR).

RAS family proteins are important signaling molecules that regulate cell growth, survival and differentiation by coupling receptor activation to downstream effector pathways. Three distinct genes encode for the three different proteins H-, K-, and N- RAS. These proteins share high sequence homology, particularly at the N-Terminal domain. Among them, K-RAS is one of the most frequently mutated in human cancer. The majority of the mutations present in K-RAS are at codon 12 (from 80 to 100%) followed by codon 13 and 61. In all cases, aminoacid change leads to a constitutively activated protein. K-RAS mutations have a role in tumor development as well as in tumor progression and resistance. Despite the various studies which have been published, the prognostic and predictive role of K-RAS mutations is still under debate. Keeping in mind that the glycine present at position 12 can be substituted by valine, aspartic acid or cysteine, it could be well understood that each different substitution plays a different role in K-RAS-dependent processes. The present article focuses on the molecular and biological characteristics of K-RAS protein, its role in NSCLC tumor development and progression. We also present an overview of the preclinical models both in vitro and in vivo available to determine the role of K-RAS in tumor progression and response to treatment and on the recent results obtained in this field. Finally, we have considered the impact of KRAS mutations in clinical practice, analyzing the different recent trials that have taken into consideration K-RAS.