bims-glucam 2020-11-08 papers

Issue of 2020‒11‒08
six papers selected by
Sreeparna Banerjee
Middle East Technical University

Transl Oncol. 2020 Oct 30. pii: S1936-5233(20)30412-5. [Epub ahead of print]14(1): 100920

Targeted inhibition of glutamine metabolism enhances the antitumor effect of selumetinib in KRAS-mutant NSCLC.

Meng Xia, Xuena Li, Yao Diao, Bulin Du, Yaming Li.

Regulated by the tumor microenvironment, the metabolic network of the tumor is reprogrammed, driven by oncogenes and tumor suppressor genes. The metabolic phenotype of tumors of different driven-genes and different tissue types is extremely heterogeneous. KRAS-mutant non-small cell lung cancer (NSCLC) has glutamine dependence. In this study, we demonstrated that glutamine utilization of KRAS-mutant NSCLC was higher than that of KRAS wild-type. CB839, an efficient glutaminase inhibitor, synergized with the MEK inhibitor selumetinib to enhance antitumor activity in KRAS-mutant NSCLC cells and xenografts, and the therapeutic response could be well identified by 18F-FDG PET imaging. Combination therapy induced redox stress, manifesting as a decrease in mitochondrial membrane potential and an increase in ROS levels, and energetic stress manifesting as suppression of glycolysis and glutamine degradation. The phosphorylation of AKT was also suppressed. These effects combined to induce autophagy and thereby caused cancer cell death. Our results suggest that dual inhibition of the MEK-ERK pathway and glutamine metabolism activated by KRAS mutation may be an effective treatment strategy for KRAS-driven NSCLC.

Keywords: Autophagy; Glutaminase; KRAS; Microenvironment

DOI: https://doi.org/10.1016/j.tranon.2020.100920

Cell Signal. 2020 Oct 30. pii: S0898-6568(20)30297-7. [Epub ahead of print] 109820

p53-dependent glutamine usage determines susceptibility to oxidative stress in radioresistant head and neck cancer cells.

Hyo Won Chang, MyungJin Lee, Yoon Sun Lee, Song Hee Kim, Jong Cheol Lee, Jung Je Park, Hae Yun Nam, Mi Ra Kim, Myung Woul Han, Seong Who Kim, Sang Yoon Kim.

The manner in which p53 maintains redox homeostasis and the means by which two key metabolic elements, glucose and glutamine, contribute to p53-dependent redox stability remain unclear. To elucidate the manner in which p53 deals with glucose-deprived, reactive oxygen species (ROS)-prone conditions in this regard, two isogenic cancer subclones (HN3R-A and HN3R-B) bearing distinct p53 mutations as an in vitro model of intratumoral p53 heterogeneity were identified. Following cumulative irradiation, the subclones showed a similar metabolic shift to aerobic glycolysis and increasing NADPH biogenesis for cellular defense against oxidative damage irrespective of p53 status. The radioresistant cancer cells became more sensitive to glycolysis-targeting drugs. However, in glucose-deprived and ROS-prone conditions, HN3R-B, the subclone with the original p53 increased the utilization of glutamine by GLS2, thereby maintaining redox homeostasis and ATP. Conversely, HN3R-A, the p53-deficient radioresistant subclone displayed an impairment in glutamine usage and high susceptibility to metabolic stresses as well as ROS-inducing agents despite the increased ROS scavenging system. Collectively, our findings suggest that p53 governs the alternative utilization of metabolic ingredients, such as glucose and glutamine, in ROS-prone conditions. Thus, p53 status may be an important biomarker for selecting cancer treatment strategies, including metabolic drugs and ROS-inducing agents, for recurrent cancers after radiotherapy.

Keywords: Glutamine; Glycolytic shift; Radioresistant cancer cells; Reactive oxygen species; p53

DOI: https://doi.org/10.1016/j.cellsig.2020.109820

ACS Omega. 2020 Oct 27. 5(42): 27304-27313

Isolation and Metabolic Assessment of Cancer Cell Mitochondria.

Nguyen Phuoc Long, Jung Eun Min, Nguyen Hoang Anh, Sun Jo Kim, Seongoh Park, Hyung Min Kim, Sang Jun Yoon, Johan Lim, Seul Ji Lee, Sung Won Kwon.

Mitochondrial metabolism plays an essential role in various biological processes of cancer cells. Herein, we established an experimental procedure for the metabolic assessment of mitochondria in cancer cells. We examined procedures for mitochondrial isolation coupled with various mitochondrial extraction buffers in three major cancer cell lines (PANC1, A549, and MDA-MB-231) and identified a potentially optimal and generalized approach. The purity of the mitochondrial fraction isolated by the selected protocol was verified using specific protein markers of cellular components, and the ultrastructure of the isolated mitochondria was also analyzed by transmission electron microscopy. The isolation procedure, involving a bead beater for cell lysis, a modified sucrose buffer, and differential centrifugation, appeared to be a suitable method for the extraction of mitochondria from cancer cells. Electron micrographs indicated an intact two-layer membrane and inner structures of mitochondria isolated by this procedure. Metabolomic and lipidomic analyses were conducted to examine the metabolic phenotypes of the mitochondria-enriched fractions and associated bulk cancer cells. A total of 44 metabolites, including malate and succinate, occurred at significantly higher levels in the mitochondrial fractions, whereas 51 metabolites, including citrate, oxaloacetate, and fumarate of the Krebs cycle and the oncometabolites glutamine and glutamate, were reduced in mitochondria compared to that in the corresponding bulk cells of PANC1. Similar patterns were observed in mitochondria and bulk cells of MDA-MB-231 and A549 cell lines. A clear difference between the lipid profiles of bulk PANC1, MDA-MB-231, and A549 and corresponding mitochondrial fractions of these cell lines was detected by principal component analysis. In conclusion, we developed an experimental procedure for a large-scale metabolic assessment for suborganelle metabolic profiling and multiple omics data integration in cancer cells with broad applications.

DOI: https://doi.org/10.1021/acsomega.0c03612

Arch Biochem Biophys. 2020 Oct 31. pii: S0003-9861(20)30668-8. [Epub ahead of print] 108659

Metabolic interventions: A new insight into the cancer immunotherapy.

Tao Yu, Tianhan Dong, Haniyeh Eyvani, Yuanzhang Fang, Xiyu Wang, Xinna Zhang, Xiongbin Lu.

Metabolic reprogramming confers cancer cells plasticity and viability under harsh conditions. Such active alterations lead to cell metabolic dependency, which can be exploited as an attractive target in development of effective antitumor therapies. Similar to cancer cells, activated T cells also execute global metabolic reprogramming for their proliferation and effector functions when recruited to the tumor microenvironment (TME). However, the high metabolic activity of rapidly proliferating cancer cells can compete for nutrients with immune cells in the TME, and consequently, suppressing their anti-tumor functions. Thus, therapeutic strategies could aim to restore T cell metabolism and anti-tumor responses in TME by targeting the metabolic dependence of cancer cells. In this review, we highlight current research progress on metabolic reprogramming and the interplay between cancer cells and immune cells. We also discuss potential therapeutic intervention strategies for targeting metabolic pathways to improve tumor immunotherapy efficacy.

Keywords: Metabolic reprogramming; Nutrients competing; Tumor microenvironment; Tumor-infiltrating lymphocytes

DOI: https://doi.org/10.1016/j.abb.2020.108659

Elife. 2020 Nov 02. pii: e60151. [Epub ahead of print]9

eIF4E S209 phosphorylation licenses Myc-and stress-driven oncogenesis.

Hang Ruan, Xiangyun Li, Xiang Xu, Brian J Leibowitz, Jingshan Tong, Lujia Chen, Luoquan Ao, Wei Xing, Jianhua Luo, Yanping Yu, Robert E Schoen, Nahum Sonenberg, Xinghua Lu, Lin Zhang, Jian Yu.

To better understand a role of eIF4E S209 in oncogenic translation, we generated EIF4ES209A/+ heterozygous knockin (4EKI) HCT 116 human colorectal cancer (CRC) cells. 4EKI had little on total eIF4E levels, cap binding or global translation, while markedly reduced HCT 116 cell growth in spheroids and mice, and CRC organoid growth. 4EKI strongly inhibited Myc and ATF4 translation, the integrated Stress Response (ISR)-dependent glutamine metabolic signature, AKT activation and proliferation in vivo. 4EKI inhibited polyposis in ApcMin/+ mice by suppressing Myc protein and AKT activation. Furthermore, p-eIF4E was highly elevated in CRC precursor lesions in mouse and human. p-eIF4E cooperated with mutant KRAS to promote Myc and ISR-dependent glutamine addiction in various CRC cell lines, characterized by increased cell death, transcriptomic heterogeneity and immune suppression upon deprivation. These findings demonstrate a critical role of eIF4E S209-dependent translation in Myc and stress-driven oncogenesis and as a potential therapeutic vulnerability.

Keywords: cancer biology; human; mouse

DOI: https://doi.org/10.7554/eLife.60151

Inflammation. 2020 Oct 31.

L-Glutamine and Physical Exercise Prevent Intestinal Inflammation and Oxidative Stress Without Improving Gastric Dysmotility in Rats with Ulcerative Colitis.

Raisa de Oliveira Santos, Geovane da Silva Cardoso, Lara da Costa Lima, Mickael Laudrup de Sousa Cavalcante, Mariana Sousa Silva, Ana Karolina Martins Cavalcante, Juliana Soares Severo, Francisca Beatriz de Melo Sousa, Gabriella Pacheco, Even Herlany Pereira Alves, Lívia Maria Soares Nobre, Jand Venes Rolim Medeiros, Roberto Cesar Lima-Junior, Armênio Aguiar Dos Santos, Moisés Tolentino.

The aim of this study was to evaluate the effects of glutamine supplementation or exercise on gastric emptying and intestinal inflammation in rats with ulcerative colitis (UC). Strength exercise consisted of jump training 4 × 10 repetitions/5 days a week/8 weeks with progressive overload. Endurance exercise consisted of swimming without overload for a period of 1 h a day/5 days a week/8 weeks. Another group (sedentary) of animals was supplemented with L-glutamine (1 g/kg of body weight) orally for 8 weeks before induction of UC. Colitis was induced by intra-colonic administration of 1 mL of 4% acetic acid. We assessed gastric emptying, macroscopic and microscopic scoring, oxidative stress markers, and IL-1β, IL-6, and (TNF-α) levels. The UC significantly increased (p < 0.05) the gastric emptying compared with the saline control group. We observed a significantly decrease (p < 0.05) in body weight gain in UC rats compared with the control groups. Both exercise interventions and L-glutamine supplementation significantly prevented (p < 0.05) weight loss compared with the UC group. Strength and endurance exercises significantly prevented (p < 0.05) the increase of microscopic scores and oxidative stress (p < 0.05). L-glutamine supplementation in UC rats prevented hemorrhagic damage and improved oxidative stress markers (p < 0.05). Strength and endurance exercises and glutamine decreased the concentrations of inflammatory cytokines IL-1β, IL-6, and TNF-α compared with the UC group (p < 0.05). Strength and endurance exercises and L-glutamine supplementation prevented intestinal inflammation and improved cytokines and oxidative stress levels without altering gastric dysmotility in rats with UC.

Keywords: L-glutamine; gastric emptying; intestinal inflammation; physical exercise; ulcerative colitis

DOI: https://doi.org/10.1007/s10753-020-01361-3