A Critical Role of Glutamine and Asparagine γ-Nitrogen in Nucleotide Biosynthesis in Cancer Cells Hijacked by an Oncogenic Virus

Zhu, Ying; Li, Tingting; Silva, Suzane Ramos da; Lee, Jae Jin; Liu, Chun; Eoh, Hyungjin; Jung, Jae U.; Gao, Shou‐Jiang

doi:10.1128/mbio.01179-17

Cited by 64 publications

(67 citation statements)

References 51 publications

(84 reference statements)

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“…Glutamine is required by many cancer cells for their survival. Studies demonstrate that KSHV has evolved to exploit the cellular metabolism for its survival and maintenance of latently infected cells and to require glutamine for anabolic proliferation of KSHV-transformed cells (64,65) and maintenance of endothelial cells latently infected with KSHV (42). Loss of HACE1 has been linked with ROS-dependent increased glutamine uptake in mouse embryonic fibroblasts (43).…”

Section: Discussionmentioning

confidence: 99%

HACE1, an E3 Ubiquitin Protein Ligase, Mitigates Kaposi’s Sarcoma-Associated Herpesvirus Infection-Induced Oxidative Stress by Promoting Nrf2 Activity

Kumar

Roy

Asha

et al. 2019

J Virol

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Kaposi's sarcoma-associated herpesvirus (KSHV)-induced activation of nuclear factor erythroid 2-related factor 2 (Nrf2) is essential for both the expression of viral genes (latency) and modulation of the host antioxidant machinery. Reactive oxygen species (ROS) are also regulated by the ubiquitously expressed HACE1 protein (HECT domain and ankyrin repeat containing E3 ubiquitin protein ligase 1), which targets the Rac1 protein for proteasomal degradation, and this blocks the generation of ROS by Rac1-dependent NADPH oxidases. In this study, we examined the role of HACE1 in KSHV infection. Elevated levels of HACE1 expression were observed in de novo KSHV-infected endothelial cells, KSHV latently infected TIVE-LTC and PEL cells, and Kaposi's sarcoma skin lesion cells. The increased HACE1 expression in the infected cells was mediated by KSHV latent protein kaposin A. HACE1 knockdown resulted in high Rac1 and Nox 1 (NADPH oxidase 1) activity, increased ROS (oxidative stress), increased cell death, and decreased KSHV gene expression. Loss of HACE1 impaired KSHV infection-induced phosphoinositide 3-kinase (PI3-K), protein kinase C-(PKC-), extracellular signal-regulated kinase 1/2 (ERK1/2), NF-B, and Nrf2 activation and nuclear translocation of Nrf2, and it reduced the expression of Nrf2 target genes responsible for balancing the oxidative stress. In the absence of HACE1, glutamine uptake increased in the cells to cope with the KSHV-induced oxidative stress. These findings reveal for the first time that HACE1 plays roles during viral infection-induced oxidative stress and demonstrate that HACE1 facilitates resistance to KSHV infectioninduced oxidative stress by promoting Nrf2 activity. Our studies suggest that HACE1 could be a potential target to induce cell death in KSHV-infected cells and to manage KSHV infections. IMPORTANCE ROS play important roles in several cellular processes, and increased ROS cause several adverse effects. KSHV infection of endothelial cells induces ROS, which facilitate virus entry by amplifying the infection-induced host cell signaling cascade, which, in turn, induces the nuclear translocation of phospho-Nrf2 protein to regulate the expression of antioxidative genes and viral genes. The present study demonstrates that KSHV infection induces the E3 ligase HACE1 protein to regulate KSHV-induced oxidative stress by promoting the activation of Nrf2 and nuclear translocation. Absence of HACE1 results in increased ROS and cellular death and reduced nuclear Nrf2, antioxidant, and viral gene expression. Together, these studies suggest that HACE1 can be a potential target to induce cell death in KSHV-infected cells.

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Section: Discussionmentioning

confidence: 99%

HACE1, an E3 Ubiquitin Protein Ligase, Mitigates Kaposi’s Sarcoma-Associated Herpesvirus Infection-Induced Oxidative Stress by Promoting Nrf2 Activity

Kumar

Roy

Asha

et al. 2019

J Virol

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“…We have previously shown that KSHV suppresses glucose uptake and aerobic glycolysis but upregulates glutamine metabolism to promote cell survival and growth proliferation in KSHV-transformed cells (12,13). In this report, we have demonstrated that KSHV regulates ASS1 expression to maintain NO production, which is essential for the survival and proliferation of KSHV-transformed cells.…”

Section: Discussionmentioning

confidence: 57%

“…ASS1 is upregulated in KSHV-infected and -transformed cells. We have previously shown that KSHV-transformed cells depend on glutamine for anabolic proliferation (12). Because active glutamine consumption is tightly regulated, we hypothesized that KSHV-transformed cells would have an active citrulline-NO cycle.…”

Section: Resultsmentioning

confidence: 99%

Oncogenic Kaposi’s Sarcoma-Associated Herpesvirus Upregulates Argininosuccinate Synthase 1, a Rate-Limiting Enzyme of the Citrulline-Nitric Oxide Cycle, To Activate the STAT3 Pathway and Promote Growth Transformation

Zhu

Cheng

et al. 2019

J Virol

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Cancer cells are required to rewire existing metabolic pathways to support their abnormal proliferation. We have previously shown that, unlike glucose-addicted cancers, Kaposi’s sarcoma-associated herpesvirus (KSHV)-transformed cells depend on glutamine rather than glucose for energy production and amino acid and nucleotide syntheses. High-level consumption of glutamine is tightly regulated and often coupled with the citrulline-nitric oxide (NO) cycle. We have found that KSHV infection accelerates nitrogen efflux by upregulating the expression of argininosuccinate synthase 1 (ASS1), a key enzyme in the citrulline-NO cycle. KSHV utilizes multiple microRNAs to upregulate ASS1 expression. Depletion of either ASS1 or inducible nitric oxide synthase (iNOS) in KSHV-transformed cells suppresses growth proliferation, abolishes colony formation in soft agar, and decreases NO generation. Furthermore, by maintaining intracellular NO levels, ASS1 expression facilitates KSHV-mediated activation of the STAT3 pathway, which is critical for virus-induced transformation. These results illustrate a novel mechanism by which an oncogenic virus hijacks a key metabolic pathway to promote growth transformation and reveal a potential novel therapeutic target for KSHV-induced malignancies. IMPORTANCE We have previously shown that Kaposi’s sarcoma-associated herpesvirus (KSHV)-transformed cells depend on glutamine rather than glucose for energy production and amino acid and nucleotide syntheses. In this study, we have further examined how the KSHV-reprogramed metabolic pathways are regulated and discovered that KSHV hijacks the citrulline-nitric oxide (NO) cycle to promote growth proliferation and transformation. Multiple KSHV-encoded microRNAs upregulate argininosuccinate synthase 1 (ASS1), a key enzyme in the citrulline-NO cycle. ASS1 is required for KSHV-induced proliferation, colony formation in soft agar, and NO generation of KSHV-transformed cells, which also depends on inducible nitric oxide synthase. By maintaining intracellular NO levels, ASS1 mediates KSHV activation of the STAT3 pathway, which is essential for KSHV-induced abnormal cell proliferation and transformation. These results illustrate a novel mechanism by which an oncogenic virus hijacks a key metabolic pathway to promote growth transformation and reveal a potential novel therapeutic target for KSHV-induced malignancies.

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“…A new study indicates that asparagine controls breast cancer metastasis in an animal model 27 . Asparagine is also important for cancer cell proliferation in multiple cancer cells, especially in the absence of glutamine, due to the requirement for various functions of asparagine 23,24,28,49,50 . The key role of asparagine bioavailability in cancer development might, at least partly, account for its limited supply in mammalian cells.…”

Section: Discussionmentioning

confidence: 99%

“…For example, asparagine acts as a metabolic regulator of TCA cycle intermediates and the cellular supply of nitrogen (which supports the synthesis of non-essential amino acids); and for cancer cells, asparagine bioavailability is essential for survival, proliferation and tumor development 23,24,27,28 . Asparagine is also important for supporting kaposi’s sarcoma-associated herpes virus (KSHV) transformed cancer cell proliferation during glutamine depletion 29 . However, the role of asparagine and its availability in virus replication has not been explored.…”

mentioning

confidence: 99%

Asparagine availability is an essential limiting factor for poxvirus protein synthesis

Pant

Cao

Yang

2018

Preprint

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27Virus actively interfaces with host metabolism because viral replication relies on host cells to 28 provide nutrients and energy. For efficient viral replication in culture, vaccinia virus (VACV; the 29 prototype poxvirus) prefers glutamine to glucose, to the extent that in glutamine-free medium, 30VACV replication is inefficient. Remarkably, VACV replication can be fully rescued from 31 glutamine depletion by asparagine supplementation. By global metabolic profiling, genetic and 32 chemical intervening of asparagine supply, we provide evidence demonstrating that the 33 requirement of asparagine for efficient viral replication accounts for VACV's preference of 34 glutamine to glucose, rather than because glutamine is superior to glucose in feeding the 35 tricarboxylic acid (TCA) cycle. Further, we show that asparagine availability is a critical factor for 36 efficient viral protein synthesis. Our study highlights that the asparagine metabolism, whose 37 regulation has been evolutionarily tailored in mammalian cells, presents a critical barrier to 38 poxvirus replication, suggesting new directions of anti-viral strategy development. 40 41Protein synthesis 42 3 Viruses do not have metabolisms; so viral replication relies on the supply and availability of host 43 nutrients and energy. Not surprisingly, metabolism is a key interface of virus-host interactions, 44 with many viral infections characterized by requirements for particular metabolites (e.g., 45glutamine, glucose or fatty acids) for optimal replication. Conceivably, many viruses induce 46 alterations in metabolic pathways such as glycolysis, synthesis of fatty acids and nucleotides, 47 and energy metabolism, and these changes shape the outcomes of viral infections 1-4 . 49Vaccinia virus (VACV) is the prototype poxvirus, with a large double-stranded DNA genome that 50 encodes more than 200 annotated genes 5,6 . Many poxviruses cause fatal diseases, including 51 smallpox, one of the most devastating infectious diseases in human history. Although 52 eradicated in nature, smallpox is still a valid national-security concern through potential 53 unregistered stocks or de novo synthesis of live variola virus, the causative agent of smallpox 7-54 9 . Poxviruses not only cause deadly epidemics, however, because poxviruses are practically 55 useful as oncolytic agents for cancer treatments, vectors for vaccine development, and 56 recombinant protein production 10-13 . For efficient VACV replication in cell culture, VACV prefers 57 glutamine to glucose, i.e. depletion of glutamine, but not glucose, from culture medium 58 significantly decreases VACV production 14,15 . In line with this finding, VACV infection 59 upregulates glutamine metabolism 16 . Nevertheless, why VACV prefers glutamine to glucose for 60 replication remains unknown. 62Glutamine is a non-essential amino acid that is abundantly utilized by mammalian cells beyond 63 its role as a protein building block 17 . Glutamine feeds the tricarboxylic acid cycle (TCA cycle; 64 Fig. 1A) through glutamate and al...

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A Critical Role of Glutamine and Asparagine γ-Nitrogen in Nucleotide Biosynthesis in Cancer Cells Hijacked by an Oncogenic Virus

Cited by 64 publications

References 51 publications

HACE1, an E3 Ubiquitin Protein Ligase, Mitigates Kaposi’s Sarcoma-Associated Herpesvirus Infection-Induced Oxidative Stress by Promoting Nrf2 Activity

HACE1, an E3 Ubiquitin Protein Ligase, Mitigates Kaposi’s Sarcoma-Associated Herpesvirus Infection-Induced Oxidative Stress by Promoting Nrf2 Activity

Oncogenic Kaposi’s Sarcoma-Associated Herpesvirus Upregulates Argininosuccinate Synthase 1, a Rate-Limiting Enzyme of the Citrulline-Nitric Oxide Cycle, To Activate the STAT3 Pathway and Promote Growth Transformation

Asparagine availability is an essential limiting factor for poxvirus protein synthesis

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