bims-meluca Biomed News
on Metabolism of non-small cell lung carcinoma
Issue of 2019‒05‒26
eight papers selected by
Cristina Muñoz Pinedo
L’Institut d’Investigació Biomèdica de Bellvitge

  1. Br J Cancer. 2019 May 22.
    Sellers K, Allen TD, Bousamra M, Tan J, Méndez-Lucas A, Lin W, Bah N, Chernyavskaya Y, MacRae JI, Higashi RM, Lane AN, Fan TW, Yuneva MO.
      BACKGROUND: Previous studies suggested that the metabolism is differently reprogrammed in the major subtypes of non-small cell lung cancer (NSCLC), squamous cell carcinomas (SCC) and adenocarcinomas (AdC). However, a comprehensive analysis of this differential metabolic reprogramming is lacking.METHODS: Publicly available gene expression data from human lung cancer samples and cell lines were analysed. Stable isotope resolved metabolomics were performed on SCC and ADC tumours in human patients and in freshly resected tumour slices.
    RESULTS: Analysis of multiple transcriptomics data from human samples identified a SCC-distinguishing enzyme gene signature. SCC tumours from patients infused with [U-13C]-glucose and SCC tissue slices incubated with stable isotope tracers demonstrated differential glucose and glutamine catabolism compared to AdCs or non-cancerous lung, confirming increased activity through pathways defined by the SCC metabolic gene signature. Furthermore, the upregulation of Notch target genes was a distinguishing feature of SCCs, which correlated with the metabolic signature. Notch and MYC-driven murine lung tumours recapitulated the SCC-distinguishing metabolic reprogramming. However, the differences between SCCs and AdCs disappear in established cell lines in 2D culture.
    CONCLUSIONS: Our data emphasise the importance of studying lung cancer metabolism in vivo. They also highlight potential targets for therapeutic intervention in SCC patients including differentially expressed enzymes that catalyse reactions in glycolysis, glutamine catabolism, serine, nucleotide and glutathione biosynthesis.
  2. Elife. 2019 May 20. pii: e45572. [Epub ahead of print]8
    Kang YP, Torrente L, Falzone A, Elkins CM, Liu M, Asara JM, Dibble CC, DeNicola G.
      NRF2 is emerging as a major regulator of cellular metabolism. However, most studies have been performed in cancer cells, where co-occurring mutations and tumor selective pressures complicate the influence of NRF2 on metabolism. Here we use genetically engineered, non-transformed primary murine cells to isolate the most immediate effects of NRF2 on cellular metabolism. We find that NRF2 promotes the accumulation of intracellular cysteine and engages the cysteine homeostatic control mechanism mediated by cysteine dioxygenase 1 (CDO1), which catalyzes the irreversible metabolism of cysteine to cysteine sulfinic acid (CSA). Notably, CDO1 is preferentially silenced by promoter methylation in human non-small cell lung cancers (NSCLC) harboring mutations in KEAP1, the negative regulator of NRF2. CDO1 silencing promotes proliferation of NSCLC by limiting the futile metabolism of cysteine to the wasteful and toxic byproducts CSA and sulfite (SO32-), and depletion of cellular NADPH. Thus, CDO1 is a metabolic liability for NSCLC cells with high intracellular cysteine, particularly NRF2/KEAP1 mutant cells.
    Keywords:  biochemistry; cancer biology; chemical biology; human; mouse
  3. J Biol Chem. 2019 May 24. pii: jbc.RA119.007784. [Epub ahead of print]
    Lypova N, Telang S, Chesney J, Imbert-Fernandez Y.
      Constitutive activation of the epidermal growth factor receptor (EGFR) due to somatic mutations of the EGFR gene is commonly observed in tumors of non-small cell lung cancer (NSCLC) patients. Consequently, tyrosine kinase inhibitors (TKI) targeting the EGFR are among the most effective therapies for patients with sensitizing EGFR mutations. Clinical responses to the EGFR-targeting TKIs are evaluated through 2-[18F]-fluoro-2-deoxy-glucose (18FDG-PET) uptake, which is decreased in patients responding favorably to therapy and is positively correlated with survival. Recent studies have reported that EGFR signaling drives glucose metabolism in NSCLC cells; however, the precise downstream effectors required for this EGFR-driven metabolic effect are largely unknown. 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase  (PFKFB3) is an essential glycolytic regulator that is consistently overexpressed in lung cancer. Here, we found that PFKFB3 is an essential target of EGFR signaling and that PFKFB3 activation is required for glycolysis stimulation upon EGFR activation. We demonstrate that exposing NSCLC cells harboring either wildtype or mutated EGFR to EGF rapidly increases PFKFB3 phosphorylation, expression, and activity, and that PFKFB3 inhibition markedly reduces the EGF-mediated increase in glycolysis. Furthermore, we found that prolonged NSCLC cell exposure to the TKI erlotinib drives PFKFB3 expression and that chemical PFKFB3 inhibition synergizes with erlotinib in increasing erlotinib's anti-proliferative activity in NSCLC cells. We conclude that PFKFB3 has a key role in mediating glucose metabolism and survival of NSCLC cells in response to EGFR signaling. These results support the potential clinical utility of using PFKFB3 inhibitors in combination with EGFR-TKIs to manage NSCLC.
    Keywords:  6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase; PFKFB3; epidermal growth factor (EGF); epidermal growth factor receptor (EGFR); erlotinib; glycolysis; lung cancer; metabolism; tumorigenesis; tyrosine kinase inhibitor
  4. BMC Cancer. 2019 May 20. 19(1): 474
    Van Nest SJ, Nicholson LM, Pavey N, Hindi MN, Brolo AG, Jirasek A, Lum JJ.
      BACKGROUND: Radiation therapy is a standard form of treating non-small cell lung cancer, however, local recurrence is a major issue with this type of treatment. A better understanding of the metabolic response to radiation therapy may provide insight into improved approaches for local tumour control. Cyclic hypoxia is a well-established determinant that influences radiation response, though its impact on other metabolic pathways that control radiosensitivity remains unclear.METHODS: We used an established Raman spectroscopic (RS) technique in combination with immunofluorescence staining to measure radiation-induced metabolic responses in human non-small cell lung cancer (NSCLC) tumour xenografts. Tumours were established in NOD.CB17-Prkdcscid/J mice, and were exposed to radiation doses of 15 Gy or left untreated. Tumours were harvested at 2 h, 1, 3 and 10 days post irradiation.
    RESULTS: We report that xenografted NSCLC tumours demonstrate rapid and stable metabolic changes, following exposure to 15 Gy radiation doses, which can be measured by RS and are dictated by the extent of local tissue oxygenation. In particular, fluctuations in tissue glycogen content were observed as early as 2 h and as late as 10 days post irradiation. Metabolically, this signature was correlated to the extent of tumour regression. Immunofluorescence staining for γ-H2AX, pimonidazole and carbonic anhydrase IX (CAIX) correlated with RS-identified metabolic changes in hypoxia and reoxygenation following radiation exposure.
    CONCLUSION: Our results indicate that RS can identify sequential changes in hypoxia and tumour reoxygenation in NSCLC, that play crucial roles in radiosensitivity.
    Keywords:  Hypoxia; Immunofluorescence; Ionizing radiation; Non-small cell lung cancer; Raman spectroscopy; Reoxygenation
  5. J Cell Biochem. 2019 May 20.
    Yan J, Zhang D, Han Y, Wang Z, Ma C.
      SR splicing-factors (SRSFs) play a vital role in carcinogenesis. SRSF5 was demonstrated to be upregulated in lung cancer and identified as a novel prognostic indicator for small-cell lung cancer. However, the role of SRSF5 in the pathogenesis of non-small cell lung cancer (NSCLC) and the molecular mechanism involved are still undefined. The expression of SRSF5 in NSCLC cells was detected by quantitative real-time polymerase chain reaction and Western blot analysis. The proliferation of cells was evaluated by cell counting kit-8 and BrdU assays. Apoptosis was assessed by flow cytometry and Western blot analysis of apoptosis-associated proteins including B-cell lymphoma 2 (Bcl-2), Bax, and cytochrome C (Cyt C). Glycolysis was detected by determining glucose consumption, lactate production, and pyruvate kinase M2 (PKM2) expression. We found that SRSF5 messenger RNA and protein levels were elevated in NSCLC cells. SRSF5 knockdown inhibited the proliferation and Ki67 expression in NSCLC cells. SRSF5 silencing increased the apoptotic rate, upregulated Bax and Cyt C, and decreased Bcl-2 level in NSCLC cells. Moreover, Knockdown of SRSF5 repressed glycolysis in NSCLC cells via reducing PKM2 expression. Enhanced glycolysis by PKM2 overexpression attenuated the effects of SRSF5 silencing on NSCLC cell proliferation and apoptosis. Overall, knockdown of SRSF5 inhibited proliferative ability and induced apoptosis by suppressing PKM2 expression in NSCLC cells.
    Keywords:  NSCLC; PKM2; SRSF5; apoptosis; glycolysis; proliferation
  6. Clin Chim Acta. 2019 May 16. pii: S0009-8981(19)31863-7. [Epub ahead of print]
    Tang Y, Li Z, Lazar L, Fang Z, Tang C, Zhao J.
      Lung cancer is one of the most common cancers in the world. Due to the limitations of current diagnostic techniques and methods, most lung cancers are diagnosed at the advanced stage, which is not conducive to early treatment. The rise of metabolomics has provided new ideas for the early diagnosis of lung cancer. As a method for the comprehensive analysis of endogenous metabolites of the biological system, metabolomics has shown significant application potential for the early diagnosis and individualized treatment of various cancers including lung cancers. Via advanced analytical techniques and bioinformatics tools, the metabolome was excavated to find biomarkers related to cancer and its prognosis. In this review, the research methods and workflow of metabolomics are summarized, with an emphasis on the recent discovery of biomarkers and major metabolic pathways for lung cancers.
    Keywords:  Biomarker; Lung cancer; Metabolic pathways; Metabolomics; Workflow
  7. Mol Oncol. 2019 May 22.
    Tavassoly I, Hu Y, Zhao S, Mariottini C, Boran A, Chen Y, Li L, Tolentino RE, Jayaraman G, Goldfarb J, Gallo J, Iyengar R.
      The ability to predict responsiveness to drugs in individual patients is limited. We hypothesized that integrating molecular information from databases would yield predictions that could be experimentally tested to develop transcriptomic signatures for specific drugs. We analyzed lung adenocarcinoma patient data from The Cancer Genome Atlas (TCGA) and identified a subset of patients in which xanthine dehydrogenase expression correlated with decreased survival. We tested allopurinol, an FDA-approved drug that inhibits xanthine dehydrogenase, on human Non-Small Cell Lung Cancer (NSCLC) cell lines obtained from the Broad Institute Cancer Cell Line Encyclopedia (CCLE), and identified sensitive and resistant cell lines. We utilized the transcriptomic profiles of these cell lines to identify six-gene signatures for allopurinol-sensitive and -resistant cell lines. Transcriptomic networks identified JAK2 as an additional target in allopurinol-resistant lines. Treatment of resistant cell lines with allopurinol and CEP-33779 (a JAK2 inhibitor) resulted in cell death. The effectiveness of allopurinol alone or allopurinol and CEP-33779 were verified in vivo using tumor formation in NCR-nude mice. We utilized the six-gene signatures to predict five additional allopurinol-sensitive NSCLC cell lines, and four allopurinol-resistant cell lines susceptible to combination therapy. We searched the transcriptomic data from a library of patient-derived NSCLC tumors from Jackson Laboratory to identify tumors that would be predicted to be sensitive to allopurinol or allopurinol + CEP-33779 treatment. Patient-derived tumors showed the predicted drug sensitivity in vivo. These data indicate that we can use integrated molecular information from cancer databases to predict drug responsiveness in individual patients and thus enable precision medicine.
    Keywords:   CCLE ; TCGA ; Cancer Genomics; Gene Signature; Lung cancer; Precision Oncology
  8. PLoS One. 2019 ;14(5): e0217131
    Suzuki A, Puri S, Leland P, Puri A, Moudgil T, Fox BA, Puri RK, Joshi BH.
      Pyruvate kinase M2 (PKM2) is an alternatively spliced variant, which mediates the conversion of glucose to lactate in cancer cells under normoxic conditions, known as the Warburg effect. Previously, we demonstrated that PKM2 is one of 97 genes that are overexpressed in non-small-cell lung cancer (NSCLC) cell lines. Herein, we demonstrate a novel role of subcellular PKM2 expression as a biomarker of therapeutic response after targeting this gene by shRNA or small molecule inhibitor (SMI) of PKM2 enzyme activity in vitro and in vivo. We examined two established lung cancer cell lines, nine patients derived NSCLC and three normal lung fibroblast cell lines for PKM2 mRNA, protein and enzyme activity by RT-qPCR, immunocytochemistry (ICC), and Western blot analysis. All eleven NSCLC cell lines showed upregulated PKM2 enzymatic activity and protein expression mainly in their cytoplasm. Targeting PKM2 by shRNA or SMI, NSCLC cells showed significantly reduced mRNA, enzyme activity, cell viability, and colony formation, which also downregulated cytosolic PKM2 and upregulated nuclear enzyme activities. Normal lung fibroblast cell lines did not express PKM2, which served as negative controls. PKM2 targeting by SMI slowed tumor growth while gene-silencing significantly reduced growth of human NSCLC xenografts. Tumor sections from responding mice showed >70% reduction in cytoplasmic PKM2 with low or undetectable nuclear staining by immunohistochemistry (IHC). In sharp contrast, non-responding tumors showed a >38% increase in PKM2 nuclear staining with low or undetectable cytoplasmic staining. In conclusion, these results confirmed PKM2 as a target for cancer therapy and an unique function of subcellular PKM2, which may characterize therapeutic response to anti-PKM2 therapy in NSCLC.