bims-meluca Biomed News
on Metabolism of non-small cell lung carcinoma
Issue of 2020‒10‒04
eight papers selected by
Cristina Muñoz Pinedo
L’Institut d’Investigació Biomèdica de Bellvitge

  1. Cancer Metab. 2020 ;8 22
      Abstract: Background: Rewiring of metabolism induced by oncogenic K-Ras in cancer cells involves both glucose and glutamine utilization sustaining enhanced, unrestricted growth. The development of effective anti-cancer treatments targeting metabolism may be facilitated by the identification and rational combinatorial targeting of metabolic pathways.
    Methods: We performed mass spectrometric metabolomics analysis in vitro and in vivo experiments to evaluate the efficacy of drugs and identify metabolic connectivity.
    Results: We show that K-Ras-mutant lung and colon cancer cells exhibit a distinct metabolic rewiring, the latter being more dependent on respiration. Combined treatment with the glutaminase inhibitor CB-839 and the PI3K/aldolase inhibitor NVP-BKM120 more consistently reduces cell growth of tumor xenografts. Maximal growth inhibition correlates with the disruption of redox homeostasis, involving loss of reduced glutathione regeneration, redox cofactors, and a decreased connectivity among metabolites primarily involved in nucleic acid metabolism.
    Conclusions: Our findings open the way to develop metabolic connectivity profiling as a tool for a selective strategy of combined drug repositioning in precision oncology.
    Keywords:  Combinatorial drug treatment; Glutamine; Glycolysis; Metabolic cancer therapy; Metabolic connectivity; Metabolic rewiring; Metabolic signature; Precision oncology
  2. Nat Cancer. 2020 May;1(5): 533-545
      Cancer cells express high levels of PD-L1, a ligand of the PD-1 receptor on T cells, allowing tumors to suppress T cell activity. Clinical trials utilizing antibodies that disrupt the PD-1/PD-L1 checkpoint have yielded remarkable results, with anti-PD-1 immunotherapy approved as first-line therapy for lung cancer patients. We used CRISPR-based screening to identify regulators of PD-L1 in human lung cancer cells, revealing potent induction of PD-L1 upon disruption of heme biosynthesis. Impairment of heme production activates the integrated stress response (ISR), allowing bypass of inhibitory upstream open reading frames in the PD-L1 5' UTR, resulting in enhanced PD-L1 translation and suppression of anti-tumor immunity. We demonstrated that ISR-dependent PD-L1 translation requires the translation initiation factor eIF5B. eIF5B overexpression, which is frequent in lung adenocarcinomas and associated with poor prognosis, is sufficient to induce PD-L1. These findings illuminate mechanisms of immune checkpoint activation and identify targets for therapeutic intervention.
  3. Mol Metab. 2020 Sep 30. pii: S2212-8778(20)30167-8. [Epub ahead of print] 101093
      OBJECTIVE: Tumor cells experience hypoxia, acidosis, and hypoglycemia. Metabolic adaptation to a glucose shortage is essential to maintain tumor cell survival because of their high glucose requirement. This study aimed to study the hypothesis that acidosis might promote tumor survival during a glucose shortage and if so, to explore a novel drug targeting metabolic vulnerability to glucose shortage.METHODS: Cell survival and bioenergetics metabolism were assessed in lung cancer cell lines. Our in-house small-molecule compounds were screened to identify those that kill cancer cells under low-glucose conditions. Cytotoxicity against non-cancerous cells was also assessed. Tumor growth was evaluated in vivo using a mouse engraft model.
    RESULTS: Acidosis limited the cellular consumption of glucose and ATP, causing tumor cells to enter a metabolically dormant but energetically economic state, which promoted tumor cell survival during glucose deficiency. We identified ESI-09, a previously known exchange protein directly activated by cAMP (EAPC) inhibitor, as an anticancer compound that inhibited cancer cells under low-glucose conditions, even when associated with acidosis. Bioenergetic studies showed that independent of EPAC inhibition, ESI-09 was a safer mitochondrial uncoupler than a classical uncoupler and created a futile cycling of mitochondrial respiration leading to decreased ATP production, increased ATP dissipation, and fuel scavenging. Accordingly, ESI-09 exhibited more cytotoxic effects under low-glucose conditions than under normal glucose conditions. ESI-09 was also more effective than actively proliferating cells on quiescent glucose-restricted cells. Cisplatin showed opposite effects. ESI-09 inhibited tumor growth in lung-cancer engraft mice.
    CONCLUSIONS: This study highlights the acidosis-induced promotion of tumor survival during glucose shortage and demonstrates that ESI-09 is a novel potent anticancer mitochondrial uncoupler that targets a metabolic vulnerability to glucose shortage even when associated with acidosis. The higher cytotoxicity under lower than normal glucose conditions suggests that ESI-09 is safer than conventional chemotherapy, can target the metabolic vulnerability of tumor cells to low-glucose stress, and is applicable to many cancer cell types.
    Keywords:  acidosis; glucose; lung cancer; mitochondrion; uncoupler
  4. Ther Adv Chronic Dis. 2020 ;11 2040622320957143
      Background: HPV16 E6/E7 proteins are the main oncogenes and only long-term persistent infection causes lung cancer. Our previous studies have shown that HPV16 E6/E7 protein up-regulates the expression of GLUT1 in lung cancer cells. However, whether E6 and E7 protein can promote the glucose uptake of GLUT1 and its molecular mechanism are unclear.Methods: The regulatory relationships of E6 or E7, miR-451, CAB39, PI3K/AKT, and GLUT1 were detected by double directional genetic manipulations in lung cancer cell lines. Immunofluorescence and flow cytometry were used to detect the effect of CAB39 on promoting the translocation to the plasma membrane of GLUT1. Flow cytometry and confocal microscopy were performed to detect the glucose uptake levels of GLUT1.
    Results: The overexpression both E6 and E7 proteins significantly down-regulated the expression level of miR-451, and the loss of miR-451 further up-regulated the expression of its target gene CAB39 at both protein and mRNA levels. Subsequently, CAB39 up-regulated the expression of GLUT1 at both protein and mRNA levels. Our results demonstrated that HPV16 E6/E7 up-regulated the expression and activation of GLUT1 through the HPV-miR-451-CAB39-GLUT1 axis. More interestingly, we found that CAB39 prompted GLUT1 translocation to the plasma membrane and glucose uptake, and this promotion depended on the PI3K/AKT pathway.
    Conclusion: Our findings provide new evidence to support the critical roles of miR-451 and CAB39 in the pathogenesis of HPV-related lung cancer.
    Keywords:  CAB39; GLUT1; HPV16; PI3K/AKT; lung cancer; miR-451
  5. J Surg Oncol. 2020 Oct 01.
      BACKGROUND: The aim of this study was to investigate the clinicopathological and prognostic features of operable non-small cell lung cancer (NSCLC) patients with diabetes mellitus (DM).METHODS: A total of 1231 surgically resected NSCLC patients were retrospectively reviewed. Clinicopathological characteristics were compared between patients with DM (DM group, n = 139) and those without DM (non-DM group, n = 1092). The clinical factors associated with postoperative complications and prognostic factors were identified.
    RESULTS: The DM group had distinct clinicopathological features. No significant differences in histological invasiveness or stage were found. The presence and control status of DM were independent predictors of postoperative complications. No significant differences in recurrence-free survival or cancer-specific survival were observed; however, the DM group had worse overall survival (OS). The DM group had a higher number of deaths from other diseases than the non-DM group, and these patients had significantly higher postoperative hemoglobin A1c levels than patients with cancer-related death.
    CONCLUSION: The presence and control status of preoperative DM are useful predictors of both postoperative complications and OS in operable NSCLC patients. Concomitant diabetes-related complications have a negative effect on long-term survival in diabetic NSCLC patients, and long-term glycemic control is important to prolong OS.
    Keywords:  diabetes mellitus; non-small cell lung cancer; prognostic factors
  6. Onco Targets Ther. 2020 ;13 8951-8961
      Background: Lung cancer is one of the most common causes of cancer-related deaths worldwide, metabolic disorders are also a problem that puzzles mankind. SREBP is overexpressed in non-small-cell lung cancer (NSCLC) and is also a key regulator of lipid synthesis. However, the mechanisms by which SREBP regulates the proliferation, migration and invasion in NSCLC remain unclear.Materials and Methods: CCK-8, colony formation assay, soft agar assay, scratch wound healing assay and transwell assays were performed to detect proliferation, and invasion in NSCLC cells, respectively. In addition, Western blotting assay, qPCR and immunofluorescence were applied to detect the expressions of SREBP1, SREBP2, ki-67, PCNA, Bax, bcl-2, E-cadherin, N-cadherin, Vimentin, PI3K, p-PI3k, AKT, p-AKT, mTOR, p-mTOR in NSCLC cells.
    Results: In this study, downregulation of SREBP significantly inhibited the proliferation, migration and invasion of A549 and H1299 cells. Moreover, the method of piecewise inhibition was adopted to prove that SREBP is a downstream molecule of the PI3K/Akt/mTOR signaling pathway.
    Conclusion: Our study indicated that downregulation of SREBP inhibited the growth in NSCLC cells via PI3K/AKT/mTOR signaling pathway. Thus, we suggested SREBP may serve as a potential target for the treatment of patients with NSCLC.
    Keywords:  PI3K/AKT/mTOR; SREBP; invasion; non-small-cell lung cancer; proliferation
  7. Front Genet. 2020 ;11 962
      Circular RNA mediator of cell motility 1 (circ-MEMO1) was identified as an oncogene in non-small cell lung cancer (NSCLC). Nevertheless, the working mechanism behind circ-MEMO1-mediated progression of NSCLC is barely known. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to detect the expression of circ-MEMO1, microRNA-101-3p (miR-101-3p), and KRAS proto-oncogene, GTPase (KRAS). Cell proliferation and aerobic glycolysis were detected by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and glycolysis detection kits. Flow cytometry was used to evaluate cell cycle progression and apoptosis of NSCLC cells. Western blot assay was used to measure the protein expression of hexokinase 2 (HK2), lactate dehydrogenase A (LDHA), KRAS, CD9, CD81, tumor susceptibility 101 (TSG101), and Golgi matrix protein 130 kDa (GM130). The target relationship between miR-101-3p and circ-MEMO1 or KRAS was predicted by StarBase software and confirmed by dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay, and RNA-pull down assay. In vivo tumor growth assay was conducted to assess the effect of circ-MEMO1 in vivo. Exosomes were isolated using the ExoQuick precipitation kit. Circ-MEMO1 was up-regulated in NSCLC, and high expression of circ-MEMO1 predicted poor prognosis in NSCLC patients. Circ-MEMO1 accelerated the proliferation, cell cycle progression, and glycolytic metabolism and inhibited the apoptosis of NSCLC cells. Circ-MEMO1 negatively regulated the expression of miR-101-3p through direct interaction, and si-circ-MEMO1-induced biological effects were attenuated by the introduction of anti-miR-101-3p. MiR-101-3p directly interacted with the 3' untranslated region (3' UTR) of KRAS messenger RNA (mRNA), and KRAS level was regulated by circ-MEMO1/miR-101-3p axis. Circ-MEMO1 silencing suppressed the NSCLC tumor growth in vivo. ROC curve analysis revealed that high expression of serum exosomal circ-MEMO1 (exo-circ-MEMO1) might be a valuable diagnostic marker for NSCLC. Circ-MEMO1 facilitated the progression and glycolysis of NSCLC through regulating miR-101-3p/KRAS axis.
    Keywords:  KRAS; NSCLC; circ-MEMO1; exosome; glycolysis; miR-101-3p
  8. Exp Oncol. 2020 09;42(3): 192-196
      BACKGROUND: Taking into account differences in the bioenergetics between malignant and normal cells a search of antitumor drugs among the modifiers of tumor metabolism has a reasonable excuse. Earlier it was found that the cytotoxic/cytostatic action of sodium dichloroacetate (DCA) against Lewis lung carcinoma (LLC) cells in vitro was enhanced in the case of its combination with metformin (MTF).AIM: To study the antitumor action of DCA in combination with MTF against LLC in vivo.
    MATERIALS AND METHODS: LLC/R9, a low metastatic variant of LLC cells, was used. LLC/R9 bearing mice were treated with MTF (at a total dose 0.15 g/kg b.w.) alone or in combination with DCA (at a total dose of 0.75 g/kg b.w.). LLC/R9 growth kinetics and the primary tumor growth and metastasis indices on the 23rd day after tumor cell inoculation were evaluated by routine procedures. The state of the electron transport chain of mitochondria in tumor cells was studied using electron paramagnetic resonance. The content of lactate and glucose in blood plasma from mice was measured by enzymatic methods using biochemical analyzer. The number of tumor-associated macrophages (TAMs) and their distribution by M1/M2 phenotype were estimated by flow cytometry using antibodies against CD68 and CD206.
    RESULTS: In LLC/R9-bearing mice treated with DCA in combination with MTF, tumor growth and metastasis indices, as well as circulating glucose and lactate levels were not significantly different from those in the control group. The level of nitrosylation of non-heme and heme proteins and the content of iron-sulfur centers in the mitochondria of tumor cells in LLC/R9-bearing mice administered with DCA in combination with MTF did not also differ from the corresponding indices in control. Instead, in tumors treated with MTF alone and in combination with DCA the total CD68+ TAMs count was almost 27% (p < 0.05) and 43% lower (p < 0.05) correspondingly than that in control, but this decrease was not accompanied by redistribution of CD68+/CD206+ and CD68+/D206- subsets.
    CONCLUSION: DCA in combination with MTF, at least in doses applied, did not affect LLC/R9 growth and metastasis in vivo. The complete absence of an antitumor effect of DCA in combination with MTF was simultaneously associated with the absence of significant changes in the functional state of electron transport chain of mitochondria in tumor cells, circulating glucose and lactate levels, and the decrease of the TAMs amount in tumors. It suggests that the antitumor activity of DCA and MTF could be determined by both their local effects within a tumor and their multiple systemic impacts.