bims-meluca Biomed News
on Metabolism of non-small cell lung carcinoma
Issue of 2019‒07‒28
seven papers selected by
Cristina Muñoz Pinedo
L’Institut d’Investigació Biomèdica de Bellvitge

  1. J Biol Chem. 2019 Jul 23. pii: jbc.RA119.008743. [Epub ahead of print]
    Fan TWM, Bruntz RC, Yang Y, Song H, Chernyavskaya Y, Deng P, Zhang Y, Shah PP, Beverly LJ, Qi Z, Mahan AL, Higashi RM, Dang CV, Lane AN.
      Nucleotide synthesis is essential to proliferating cells but the preferred precursors for de novo biosynthesis are not defined in human cancer tissues. We have employed multiplexed Stable Isotope Resolved Metabolomics (mSIRM) to track the metabolism of 13C6-glucose, D2-glycine, 13C2-glycine, and D3-serine into purine nucleotides in freshly resected cancerous and matched non-cancerous lung tissues from non-small cell lung cancer (NSCLC) patients and compared the metabolism with established NSCLC PC9 and A549 cell lines in vitro.  Surprisingly, 13C6-glucose was the best carbon source for purine synthesis in human NSCLC tissues, in contrast to the non-cancerous lung tissues from the same patient, which showed lower mitotic indices and MYC expression. We also observed that D3-Ser was preferentially incorporated into purine rings over D2-glycine in both tissues and cell lines. MYC suppression attenuated 13C6-glucose, D3-serine, and 13C2-glycine incorporation into purines and reduced proliferation in PC9 but not in A549 cells. Using detailed kinetic modeling, we showed that the preferred use of glucose as a carbon source for purine ring synthesis in NSCLC tissues involves cytoplasmic activation/compartmentation of the glucose-to-serine pathway and enhanced reversed one-carbon fluxes that attenuate exogenous serine incorporation into purines. Our findings also indicate that the substrate for de novo nucleotide synthesis differs profoundly between cancer cell lines and fresh human lung cancer tissues; the latter preferred glucose to exogenous serine or glycine but not the former. This distinction in substrate utilization in purine synthesis in human cancer tissues should be considered when targeting one-carbon metabolism for cancer therapy.
    Keywords:  dynamic compartmentation; ex vivo human lung tissue slice cultures; lung cancer; metabolic tracer; metabolism; multiplexed Stable Isotope-Resolved Metabolomics (mSIRM); nucleoside/nucleotide biosynthesis; one-carbon metabolism
  2. J Thorac Oncol. 2019 Jul 16. pii: S1556-0864(19)30560-X. [Epub ahead of print]
    Goeman F, De Nicola F, Scalera S, Sperati F, Gallo E, Ciuffreda L, Pallocca M, Pizzuti L, Krasniqi E, Barchiesi G, Vici P, Barba M, Buglioni S, Casini B, Visca P, Pescarmona E, Mazzotta M, De Maria R, Fanciulli M, Ciliberto G, Maugeri-Saccà M.
      INTRODUCTION: Molecular characterization studies revealed recurrent KEAP1/NFE2L2 alterations in non-small cell lung cancer (NSCLC). These genes encode two interacting proteins (stress response pathway, SRP) that mediate a cytoprotective response to oxidative stress and xenobiotics. Nevertheless, whether KEAP1/NFE2L2 mutations impact on clinical outcomes is unclear.METHODS: We performed amplicon-based next-generation sequencing to characterize the SRP in metastatic NSCLC patients (IRE cohort, N=88) treated with first-line chemotherapy. Mutations in the DNA damage response (TP53, ATM and ATR) were concomitantly analyzed. In lung adenocarcinoma (LAC), we also determined the expression of pATR and pATM. Two independent cohorts (MSKCC and TCGA) containing data from ∼1,400 advanced LAC were used to assess the reproducibility of the results.
    RESULTS: In the IRE cohort, patients whose tumors carried mutations in the KEAP1/NFE2L2 pathway had significantly shorter progression-free survival (PFS) and overall survival (OS) then their wild-type counterparts (log-rank p=0.006 and p=0.018, respectively). This association was driven by LAC where KEAP1/NFE2L2 mutations were overrepresented in fast progressors and associated with an increased risk of disease progression and death. LACs carrying KEAP1/NFE2L2 mutations were characterized by elevated expression of pATR and pATM, in association with a pattern of mutual exclusivity with TP53 alterations. The relationship between KEAP1/NFE2L2 mutations and shorter survival was validated in the MSKCC cohort (N=1,256, log-rank p<0.001) and in the TCGA cohort (N=162, log-rank p=0.039).
    CONCLUSIONS: These findings suggest that mutant SRP represents a negative prognostic/predictive factor in metastatic LAC, and that KEAP1/NFE2L2 mutations may define a molecular subtype of chemo-resistant and rapidly progressing LAC.
    Keywords:  Fast Progressors; KEAP1/NFE2L2,Stress Response Pathway; Lung Adenocarcinoma
  3. Biochem Biophys Res Commun. 2019 Jul 19. pii: S0006-291X(19)31383-X. [Epub ahead of print]
    Zhao Y, Wang XX, Wu W, Long H, Huang J, Wang Z, Li T, Tang S, Zhu B, Chen D.
      Lung cancer is the most commonly diagnosed cancer and accounts for most cancer-related mortalities worldwide. The high expression of programmed death ligand 1 (PD-L1) is an important factor that promotes immune escape of lung cancer, thus aggravates chemotherapy resistance and poor prognosis. Therefore, understanding the regulatory mechanism of PD-L1 in lung cancer is critical for tumor immunotherapy. Enhancer of Zeste homolog2 (EZH2), an epigenetic regulatory molecule with histone methyltransferase activity, promotes the formation of an immunosuppressive microenvironment. This study aimed to investigate the role of EZH2 in PD-L1 expression and in the progression of lung tumors. We found that EZH2 was upregulated in lung cancer tissues and positively correlated with PD-L1 levels and poor prognosis. Further, shRNA-expressing lentivirus mediated EZH2 knockdown suppressed both the mRNA and protein expression level of PD-L1, thus delaying lung cancer progression in vivo by enhancing anti-tumor immune responses. Moreover, the regulatory effect of EZH2 on PD-L1 depended on HIF-1α. The present results indicate that EZH2 regulates the immunosuppressive molecule PD-L1 expression via HIF-1α in non-small cell lung cancer cells.
    Keywords:  EZH2; HIF-1α; PD-L1; lung cancer
  4. Cancer Discov. 2019 Jul 26. pii: CD-18-1261. [Epub ahead of print]
    Hollstein PE, Eichner LJ, Brun SN, Kamireddy A, Svensson RU, Vera LI, Ross DS, Rymoff TJ, Hutchins A, Galvez HM, Williams AE, Shokhirev MN, Screaton RA, Berdeaux R, Shaw RJ.
      Mutations in the LKB1 (STK11) tumor suppressor are the third most frequent genetic alteration in non-small-cell lung cancer (NSCLC). LKB1 encodes a serine/threonine kinase that directly phosphorylates and activates 14 AMPK family kinases ("AMPKRs"). The function of many of the AMPKRs remains obscure, and which are most critical to the tumor suppressive function of LKB1 remains unknown. Here we combine CRISPR and genetic analysis of the AMPKR family in NSCLC cell lines and mouse models, revealing a surprising critical role for the SIK subfamily. Conditional genetic loss of Sik1 revealed increased tumor growth in mouse models of Kras-dependent lung cancer, which were further enhanced by loss of the related kinase Sik3. As most known substrates of the SIKs control transcription, gene expression analysis was performed, revealing upregulation of AP-1 and IL6 signaling in common between LKB1- and SIK1/3-deficient tumors. The SIK substrate CRTC2 was required for this effect, as well as proliferation benefits from SIK-loss.
  5. Bioorg Med Chem Lett. 2019 Jul 19. pii: S0960-894X(19)30485-8. [Epub ahead of print]
    He S, Wang Q.
      Human lactate dehydrogenase 5 (hLDH5) is an important metabolic enzyme playing critical roles in the anaerobic glycolysis. Herein, we employed an in silico method and biological validation to identify a novel hLDH5 inhibitor with a promising cellular activity under hypoxia condition. The identified compound 9 bound to hLDH5 with a Kd value of 1.02 µM, and inhibited the enzyme with an EC50 value of 0.7 µM. Compound 9 exhibited a weak potency against NCI-H1975 cell proliferation under normal condition (IC50 = 36.5 µM), while dramatically increased to 5.7 µM under hypoxia condition. In line with the observation, hLDH5 expression in NCI-H1975 cell under hypoxia condition is much higher as compared to the normal oxygenated condition, indicating the hLDH5 inhibition may contribute to the cancer cell death.
    Keywords:  Anticancer; Biochemical activity; Cancer metabolism; Human lactate dehydrogenase 5
  6. Int J Mol Sci. 2019 Jul 11. pii: E3415. [Epub ahead of print]20(14):
    Wang K, Chen B, Yin T, Zhan Y, Lu Y, Zhang Y, Chen J, Wu W, Zhou S, Mao W, Tan Y, Du B, Liu X, Ho HI, Xiao J.
      The main mechanistic function of most chemotherapeutic drugs is mediated by inducing mitochondria-dependent apoptosis. Tumor cells usually respond to upregulate autophagy to eliminate impaired mitochondria for survival. Hypothetically, inhibiting autophagy might promote mitochondria-dependent apoptosis, thus enhancing the efficacy of chemotherapeutic therapies. We previously identified N-methylparoxetine (NMP) as an inducer of mitochondrial fragmentation with subsequent apoptosis in non-small cell lung cancer (NSCLC) cells. We discovered that ROS was accumulated in NMP-treated NSCLC cells, followed by c-Jun N-terminal kinase (JNK) and p38 MAP kinase (p38) activation. This was reversed by the application of a reactive oxygen species (ROS) scavenger, N-acetylcysteine (NAC), leading to a reduction in apoptosis. Our data suggested that NMP induced apoptosis in NSCLC cells by activating mitogen-activated protein kinase (MAPK) pathway. We further speculated that the remarkable increase of ROS in NMP-treated NSCLC cells might result from an inhibition of autophagy. Our current data confirmed that NMP blocked autophagy flux at late stage wherein lysosomal acidification was inhibited. Taken together, this study demonstrated that NMP could exert dual apoptotic functions-mitochondria impairment and, concomitantly, autophagy inhibition. NMP-related excessive ROS accumulation induced apoptosis by activating the MAPK pathway in NSCLC cells.
    Keywords:  MAPK; N-Methylparoxetine; NSCLC; ROS; apoptosis; autophagy inhibition
  7. Am J Clin Oncol. 2019 Jul 19.
    Fatehi Hassanabad A, McBride SA.
      Lung cancer is the most common cancer worldwide. It also has the highest malignancy-associated mortality rate. Treatment options are limited by cancer and tumor heterogeneity, resistance to treatment options, and an advanced stage at time of diagnosis, all of which are common. Statins are a class of lipid-lowering medications that have been studied for their antitumor effects in various types of cancers. Multiple mechanisms have been proposed to explain their observed off-target effects. Most of these hypotheses focus largely on statin-induced upregulation of proapoptotic signaling pathways and mediators, and the downregulation of antineoplastic factors secondary to statin use. Preclinical and clinical studies support their use for conferring a mortality benefit and improving treatment effect in some chemotherapy-resistant subtypes of lung cancer. However, their exact mechanism of action, class-dependent effect, dose-dependent effect, potential use as adjuvant chemotherapeutics, and markers of statin-sensitivity in specific lung cancer subtypes remain areas of ongoing investigation. Herein, we review the latest literature pertinent to the role statins can play in the management of lung cancers.