Open Access

Chromatin remodeling factor lymphoid-specific helicase inhibits ferroptosis through lipid metabolic genes in lung cancer progression

Contributed equally
Chinese Journal of Cancer201736:82

https://doi.org/10.1186/s40880-017-0248-x

Received: 21 August 2017

Accepted: 19 September 2017

Published: 16 October 2017

Ferroptosis, a novel mode of non-apoptotic cell death, involves a metabolic dysfunction that results in the production of iron-dependent reactive oxygen species (ROS), an iron carrier protein (transferrin), intracellular metabolic process, and related regulators (e.g., p53 protein). Previous studies have linked ferroptosis with oncogenic Ras [1], and p53 tumor suppressor positively regulates ferroptosis by transcriptionally inhibiting the expression of the cysteine/glutamate antiporter, which is encoded by the SLC7A11 gene in human [1, 2]. Whether other factors such as epigenetic factors are involved in the process remains less known.

Chromatin modifier lymphoid specific helicase (LSH) contributes to the malignant progression of nasopharyngeal carcinoma and glioma [3]. We recently indicated that LSH was shown to co-operate with partners, such as G9a, to drive cancer progression [4, 5]. However, the molecular mechanisms, particularly in lung cancer, are not well understood. Importantly, the impact of ferroptosis in cancer progression especially in chromatin remodeling is still far from fully understood. Based on the study reported in the article entitled “EGLN1/c-Myc induced lymphoid-specific helicase inhibits ferroptosis through lipid metabolic gene expression changes,” which was recently published in Theranostics by Jiang et al. [6], such an interplay between epigenetic controls in chromatin remodeling and ferroptosis has been addressed.

Using RNA sequencing and the gene ontology analysis, we first identified a significant enrichment in pathways that related to metabolic process and the Warburg effect [6]. Moreover, the link between LSH and metabolic genes prompted us to assess the expression of two groups of metabolic genes. The first group comprised glucose transporters (GLUTs), which were important in glucose transport, and the other group comprised fatty acid desaturases (FADSs), which were dependent on reduced nicotinamide adenine dinucleotide phosphate (NAPDH). We demonstrated that LSH contributes to lung cancer progression by directly up-regulating metabolic genes including stearoyl-CoA desaturase 1 (SCD1) and FADS2. LSH-mediated increases in metabolic gene expression may occur through a DNA methylation-independent mechanism rather than through chromatin regulation [4, 7]. Furthermore, our findings provided evidence for an interaction between LSH and WD repeat domain 76 (WDR76), which is a nuclear protein containing tandem copies of WD repeats (also known as WD40 or β-transducin repeats) that has unknown function in mammals. The LSH-dependent recruitment of WDR76 to the metabolic gene promoters and the subsequent chromatin modification that leads to metabolic gene activation links epigenetic regulation by LSH to up-regulation of the emerging metabolic genes.

The ferroptotic mode of programmed necrosis was recently discovered as an apoptosis-independent form of cell death in Ras-transformed cells; the K-ras mutant is common in lung cancer [8]. Ferroptotic death is morphologically, biochemically, and genetically distinct from apoptosis, necrosis (various forms), and autophagy. This process is characterized by an overwhelming, iron-dependent accumulation of lethal lipid ROS [1, 2]. We next demonstrated that LSH decreases the lipid ROS and iron concentrations, which supports an inhibitory role of LSH in ferroptosis [6]. We demonstrated that LSH is resistant to ferroptotic cell death in cancer cells after the treatment of erastin, a ferroptosis inducer, and inhibits ferroptosis by inhibiting the cysteine/glutamate antiporter system. RNA sequencing analysis results also showed that LSH is significantly associated with the metabolic process, indicating that LSH inhibits ferroptosis by affecting these metabolic genes [6]. Interestingly, antioxidant reagents, vitamin C, and aspirin do not affect the expression of LSH or mitochondria related genes [6]. Vitamin E is regarded as a highly efficient ferroptosis inhibitor. However, vitamin E did not affect LSH expression, indicating that types of cells and diseases might affect the efficiency of ferroptosis inhibitors. Lipid ROS and iron accumulation is a key characteristic of ferrotosis; we showed that both SCD1 and FADS2, which are linked with lipid metabolism, influenced ferroptosis by affecting the lipid ROS and iron levels [6]. Moreover, inducing ferroptosis including well-designed nanomedicines might provide a new insight to treat cancer.

The iron-dependent enzymes Egl nine homolog (EGLNs) catalyze hypoxia-inducible factor (HIF) prolyl hydroxylation, which leads to HIF-1α and HIF-2α degradation. HIF-1α regulates oxygen-dependent glucose and glutamine metabolism, playing a critical role in cancer progression [9]. In fact, EGLN1 inhibition causes accumulation of circulating metabolites [9]. Interestingly, some oncometabolites stimulate EGLN activity, which leads to diminished HIF levels. For example, high extracellular glutamate levels inhibit the xCT glutamate-cysteine antiporter (a glial transporter protein that exports substantial amounts of glutamate into the extracellular fluid) and thereby interfere with cysteine uptake, which results in decreased intracellular cysteine levels [9]. Decreased intracellular cysteine levels inhibit EGLN activity and stabilize HIF-1α [10]. We found previously that oncometabolites also activated LSH expression [4]; on the basis of this, our recent study found that EGLN1 up-regulated LSH expression by inhibiting HIF‐1α, which highlights HIF‐1α as a key repressor of LSH expression [6]. EGLN2 is essential for cell death and is a candidate driver of iron chelation-mediated inhibition of cell death. Interestingly, HIF-1α and c-Myc counteract each other. Our study found that c-Myc was recruited to the HIF-1α-binding site on the LSH promoter in the normoxic state [6].

In summary, we demonstrated the crucial role of LSH in ferroptosis (Fig. 1) and considered LSH a potential therapeutic target for cancer treatment. Our findings demonstrate that ferroptosis is epigenetically regulated by LSH, which promotes lipid metabolic genes, including SCD1 and FADS2; both FADS2 and SCD1 link with the glutamate antiporter. Our results suggest that a preferential triggering of ferroptosis in cancer cells may serve as a viable therapeutic option.
Fig. 1

LSH-mediated inhibition of ferroptosis and enhancement of lung tumorigenesis. In this model, LSH acts as a novel inhibitor of ferroptosis by regulating several metabolism-related genes. LSH expression is up-regulated by c-Myc, which is enriched at the LSH promoter by the EGLN1-mediated repression of HIF-. The induced LSH interacts with WDR76, which, in turn, up-regulates the lipid metabolic genes including SCD1 and FADS2. These metabolic genes inhibit the accumulation of lipid ROS and intracellular iron, which are required for ferroptosis, and inhibition of ferroptosis by LSH ultimately promotes cancer progression. HIF-1α hypoxia-inducible factor-1α, EGLN1/3 Egl-9 family hypoxia-inducible factor 1/3, LSH lymphoid-specific helicase, WDR76 WD repeat-containing protein 76, SCD1 stearoyl-CoA desaturase 1, FADS2 fatty acid desaturase 2, ROS reactive oxygen species

Notes

Declarations

Authors’ contributions

YJ and YH drafted this paper. SL and YT designed and revised this paper. All authors read and approved the final manuscript.

Acknowledgements

We would like to thank all laboratory members for their critical discussion of this manuscript, and apologize to those not mentioned due to space limitations.

Competing interests

The authors declare that they no competing interests.

Availability of data and materials

Not applicable.

Consent for publication

Not applicable.

Ethics approval and consent to participate

Not applicable.

Funding

This work was supported by the National Natural Science Foundation of China [81372427 and 81672787 (Y. Tao), 81271763 and 81672991 (S. Liu)], and the National Basic Research Program of China [2015CB553903 (Y. Tao)].

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Authors’ Affiliations

(1)
Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Xiangya Hospital, Central South University
(2)
Key Laboratory of Carcinogenesis, Ministry of Health, Cancer Research Institute, School of Basic Medicine, Central South University
(3)
Institute of Medical Sciences, Xiangya Hospital, Central South University
(4)
Department of Thoracic Surgery, Second Xiangya Hospital, Central South University

References

  1. Dixon SJ, Lemberg KM, Lamprecht MR, Skouta R, Zaitsev EM, Gleason CE, Patel DN, Bauer AJ, Cantley AM, Yang WS, Morrison B 3rd, Stockwell BR. Ferroptosis: an iron-dependent form of nonapoptotic cell death. Cell. 2012;149:1060–72.View ArticlePubMedPubMed CentralGoogle Scholar
  2. Jiang L, Kon N, Li T, Wang SJ, Su T, Hibshoosh H, Baer R, Gu W. Ferroptosis as a p53-mediated activity during tumour suppression. Nature. 2015;520:57–62.View ArticlePubMedPubMed CentralGoogle Scholar
  3. Xiao D, Huang J, Pan Y, Li H, Fu C, Mao C, Cheng Y, Shi Y, Chen L, Jiang Y, Yang R, Liu Y, Zhou J, Cao Y, Liu S, Tao Y. Chromatin remodeling factor LSH is upregulated by the LRP6-GSK3beta-E2F1 axis linking reversely with survival in gliomas. Theranostics. 2017;7:132–43.View ArticlePubMedPubMed CentralGoogle Scholar
  4. He X, Yan B, Liu S, Jia J, Lai W, Xin X, Tang CE, Luo D, Tan T, Jiang Y, Shi Y, Liu Y, Xiao D, Chen L, Liu S, Mao C, Yin G, Cheng Y, Fan J, Cao Y, Muegge K, Tao Y. Chromatin remodeling factor LSH drives cancer progression by suppressing the activity of fumarate hydratase. Can Res. 2016;76:5743–55.View ArticleGoogle Scholar
  5. Liu S, Tao YG. Chromatin remodeling factor LSH affects fumarate hydratase as a cancer driver. Chin J Cancer. 2016;35:72.View ArticlePubMedPubMed CentralGoogle Scholar
  6. Jiang Y, Yang R, Yan B, Shi Y, Liu X, Lai W, Liu Y, Wang X, Xiao D, Zhou H, Cheng Y, Yu F, Cao Y, Liu S, Yan Q, Tao Y. EGLN1/c-Myc induced lymphoid-specific Helicase inhibits ferroptosis through lipid metabolic gene expression changes. Theranostics. 2017;7:3293–305.View ArticlePubMedPubMed CentralGoogle Scholar
  7. Liu S, Tao Y. Interplay between chromatin modifications and paused RNA polymerase II in dynamic transition between stalled and activated genes. Biol Rev Camb Philos Soc. 2013;88:40–8.View ArticlePubMedGoogle Scholar
  8. Wang P, Sun YC, Lu WH, Huang P, Hu Y. Selective killing of K-ras—transformed pancreatic cancer cells by targeting NAD(P)H oxidase. Chin J Cancer. 2015;34:166–76.PubMedGoogle Scholar
  9. Olenchock BA, Moslehi J, Baik AH, Davidson SM, Williams J, Gibson WJ, Chakraborty AA, Pierce KA, Miller CM, Hanse EA, Kelekar A, Sullivan LB, Wagers AJ, Clish CB, Vander Heiden MG, Kaelin WG Jr. EGLN1 inhibition and rerouting of alpha-ketoglutarate suffice for remote ischemic protection. Cell. 2016;164:884–95.View ArticlePubMedPubMed CentralGoogle Scholar
  10. Briggs KJ, Koivunen P, Cao S, Backus KM, Olenchock BA, Patel H, Zhang Q, Signoretti S, Gerfen GJ, Richardson AL, Witkiewicz AK, Cravatt BF, Clardy J, Kaelin WG Jr. Paracrine induction of HIF by glutamate in breast cancer: EglN1 senses cysteine. Cell. 2016;166:126–39.View ArticlePubMedPubMed CentralGoogle Scholar

Copyright

© The Author(s) 2017

Advertisement