Advertisement

Assessment of Stabilization and Activity of the HIFs Important for Hypoxia-Induced Signalling in Cancer Cells

  • David Kung-Chun Chiu
  • Misty Shuo Zhang
  • Aki Pui-Wah Tse
  • Carmen Chak-Lui WongEmail author
Protocol
Part of the Methods in Molecular Biology book series (MIMB, volume 1928)

Abstract

Blood vessels in tumors contain chaotic branching structures and leaky vessel lumens, resulting in uneven supply of oxygen in the tumor microenvironment. High metabolic and proliferation rate of tumor cells further depletes the local oxygen supply. Therefore, hypoxia is a common phenomenon in multiple solid malignancies. Hypoxia-inducible factors (HIFs) regulate the transcription of a spectrum of genes, which are vitally important for tumor cell adaption under hypoxia, and shape the tumor microenvironment to become more favorable for progression. HIFs are involved in almost every step of cancer development through inducing angiogenesis, metabolic reprogramming, metastasis, cancer stemness maintenance, chemoresistance, and immune evasion. Here, we describe methods for the assessment of HIF activity, as well as identification of novel transcriptional targets of HIFs in vitro and in vivo.

Key words

Hypoxia HIF qPCR Western blotting Luciferase reporter assay ChIP assay Immunohistochemistry 

References

  1. 1.
    Semenza GL (2012) Hypoxia-inducible factors in physiology and medicine. Cell 148(3):399–408.  https://doi.org/10.1016/j.cell.2012.01.021CrossRefPubMedPubMedCentralGoogle Scholar
  2. 2.
    Epstein AC, Gleadle JM, McNeill LA, Hewitson KS, O’Rourke J, Mole DR, Mukherji M, Metzen E, Wilson MI, Dhanda A, Tian YM, Masson N, Hamilton DL, Jaakkola P, Barstead R, Hodgkin J, Maxwell PH, Pugh CW, Schofield CJ, Ratcliffe PJ (2001) C. elegans EGL-9 and mammalian homologs define a family of dioxygenases that regulate HIF by prolyl hydroxylation. Cell 107(1):43–54CrossRefGoogle Scholar
  3. 3.
    Kaelin WG Jr, Ratcliffe PJ (2008) Oxygen sensing by metazoans: the central role of the HIF hydroxylase pathway. Mol Cell 30(4):393–402.  https://doi.org/10.1016/j.molcel.2008.04.009CrossRefPubMedGoogle Scholar
  4. 4.
    Wang GL, Jiang BH, Rue EA, Semenza GL (1995) Hypoxia-inducible factor 1 is a basic-helix-loop-helix-PAS heterodimer regulated by cellular O2 tension. Proc Natl Acad Sci U S A 92(12):5510–5514CrossRefGoogle Scholar
  5. 5.
    Semenza GL (2012) Hypoxia-inducible factors: mediators of cancer progression and targets for cancer therapy. Trends Pharmacol Sci 33(4):207–214.  https://doi.org/10.1016/j.tips.2012.01.005CrossRefPubMedPubMedCentralGoogle Scholar
  6. 6.
    Hansen WJ, Ohh M, Moslehi J, Kondo K, Kaelin WG, Welch WJ (2002) Diverse effects of mutations in exon II of the von Hippel-Lindau (VHL) tumor suppressor gene on the interaction of pVHL with the cytosolic chaperonin and pVHL-dependent ubiquitin ligase activity. Mol Cell Biol 22(6):1947–1960CrossRefGoogle Scholar
  7. 7.
    Maxwell PH, Wiesener MS, Chang GW, Clifford SC, Vaux EC, Cockman ME, Wykoff CC, Pugh CW, Maher ER, Ratcliffe PJ (1999) The tumour suppressor protein VHL targets hypoxia-inducible factors for oxygen-dependent proteolysis. Nature 399(6733):271–275.  https://doi.org/10.1038/20459CrossRefPubMedGoogle Scholar
  8. 8.
    Morris MR, Maina E, Morgan NV, Gentle D, Astuti D, Moch H, Kishida T, Yao M, Schraml P, Richards FM, Latif F, Maher ER (2004) Molecular genetic analysis of FIH-1, FH, and SDHB candidate tumour suppressor genes in renal cell carcinoma. J Clin Pathol 57(7):706–711.  https://doi.org/10.1136/jcp.2003.011767CrossRefPubMedPubMedCentralGoogle Scholar
  9. 9.
    Pollard PJ, Briere JJ, Alam NA, Barwell J, Barclay E, Wortham NC, Hunt T, Mitchell M, Olpin S, Moat SJ, Hargreaves IP, Heales SJ, Chung YL, Griffiths JR, Dalgleish A, McGrath JA, Gleeson MJ, Hodgson SV, Poulsom R, Rustin P, Tomlinson IP (2005) Accumulation of Krebs cycle intermediates and over-expression of HIF1alpha in tumours which result from germline FH and SDH mutations. Hum Mol Genet 14(15):2231–2239.  https://doi.org/10.1093/hmg/ddi227CrossRefPubMedGoogle Scholar
  10. 10.
    Selak MA, Armour SM, MacKenzie ED, Boulahbel H, Watson DG, Mansfield KD, Pan Y, Simon MC, Thompson CB, Gottlieb E (2005) Succinate links TCA cycle dysfunction to oncogenesis by inhibiting HIF-alpha prolyl hydroxylase. Cancer Cell 7(1):77–85.  https://doi.org/10.1016/j.ccr.2004.11.022CrossRefPubMedPubMedCentralGoogle Scholar
  11. 11.
    Liu MY, Poellinger L, Walker CL (2003) Up-regulation of hypoxia-inducible factor 2alpha in renal cell carcinoma associated with loss of Tsc-2 tumor suppressor gene. Cancer Res 63(10):2675–2680PubMedGoogle Scholar
  12. 12.
    Zundel W, Schindler C, Haas-Kogan D, Koong A, Kaper F, Chen E, Gottschalk AR, Ryan HE, Johnson RS, Jefferson AB, Stokoe D, Giaccia AJ (2000) Loss of PTEN facilitates HIF-1-mediated gene expression. Genes Dev 14(4):391–396PubMedPubMedCentralGoogle Scholar
  13. 13.
    Hirota K, Semenza GL (2006) Regulation of angiogenesis by hypoxia-inducible factor 1. Crit Rev Oncol Hematol 59(1):15–26.  https://doi.org/10.1016/j.critrevonc.2005.12.003CrossRefPubMedGoogle Scholar
  14. 14.
    Forsythe JA, Jiang BH, Iyer NV, Agani F, Leung SW, Koos RD, Semenza GL (1996) Activation of vascular endothelial growth factor gene transcription by hypoxia-inducible factor 1. Mol Cell Biol 16(9):4604–4613CrossRefGoogle Scholar
  15. 15.
    Kim JW, Tchernyshyov I, Semenza GL, Dang CV (2006) HIF-1-mediated expression of pyruvate dehydrogenase kinase: a metabolic switch required for cellular adaptation to hypoxia. Cell Metab 3(3):177–185.  https://doi.org/10.1016/j.cmet.2006.02.002CrossRefPubMedGoogle Scholar
  16. 16.
    Fantin VR, St-Pierre J, Leder P (2006) Attenuation of LDH-A expression uncovers a link between glycolysis, mitochondrial physiology, and tumor maintenance. Cancer Cell 9(6):425–434.  https://doi.org/10.1016/j.ccr.2006.04.023CrossRefPubMedGoogle Scholar
  17. 17.
    Semenza GL, Jiang BH, Leung SW, Passantino R, Concordet JP, Maire P, Giallongo A (1996) Hypoxia response elements in the aldolase A, enolase 1, and lactate dehydrogenase A gene promoters contain essential binding sites for hypoxia-inducible factor 1. J Biol Chem 271(51):32529–32537CrossRefGoogle Scholar
  18. 18.
    Iyer NV, Kotch LE, Agani F, Leung SW, Laughner E, Wenger RH, Gassmann M, Gearhart JD, Lawler AM, Yu AY, Semenza GL (1998) Cellular and developmental control of O2 homeostasis by hypoxia-inducible factor 1 alpha. Genes Dev 12(2):149–162CrossRefGoogle Scholar
  19. 19.
    Kim JW, Gao P, Liu YC, Semenza GL, Dang CV (2007) Hypoxia-inducible factor 1 and dysregulated c-Myc cooperatively induce vascular endothelial growth factor and metabolic switches hexokinase 2 and pyruvate dehydrogenase kinase 1. Mol Cell Biol 27(21):7381–7393.  https://doi.org/10.1128/MCB.00440-07CrossRefPubMedPubMedCentralGoogle Scholar
  20. 20.
    Semenza GL, Roth PH, Fang HM, Wang GL (1994) Transcriptional regulation of genes encoding glycolytic enzymes by hypoxia-inducible factor 1. J Biol Chem 269(38):23757–23763PubMedGoogle Scholar
  21. 21.
    Fukuda R, Zhang H, Kim JW, Shimoda L, Dang CV, Semenza GL (2007) HIF-1 regulates cytochrome oxidase subunits to optimize efficiency of respiration in hypoxic cells. Cell 129(1):111–122.  https://doi.org/10.1016/j.cell.2007.01.047CrossRefPubMedGoogle Scholar
  22. 22.
    Lai RK, Xu IM, Chiu DK, Tse AP, Wei LL, Law CT, Lee D, Wong CM, Wong MP, Ng IO, Wong CC (2016) NDUFA4L2 fine-tunes oxidative stress in hepatocellular carcinoma. Clin Cancer Res 22(12):3105–3117.  https://doi.org/10.1158/1078-0432.CCR-15-1987CrossRefPubMedGoogle Scholar
  23. 23.
    Tello D, Balsa E, Acosta-Iborra B, Fuertes-Yebra E, Elorza A, Ordonez A, Corral-Escariz M, Soro I, Lopez-Bernardo E, Perales-Clemente E, Martinez-Ruiz A, Enriquez JA, Aragones J, Cadenas S, Landazuri MO (2011) Induction of the mitochondrial NDUFA4L2 protein by HIF-1alpha decreases oxygen consumption by inhibiting Complex I activity. Cell Metab 14(6):768–779.  https://doi.org/10.1016/j.cmet.2011.10.008CrossRefPubMedGoogle Scholar
  24. 24.
    Krishnamachary B, Zagzag D, Nagasawa H, Rainey K, Okuyama H, Baek JH, Semenza GL (2006) Hypoxia-inducible factor-1-dependent repression of E-cadherin in von Hippel-Lindau tumor suppressor-null renal cell carcinoma mediated by TCF3, ZFHX1A, and ZFHX1B. Cancer Res 66(5):2725–2731.  https://doi.org/10.1158/0008-5472.CAN-05-3719CrossRefPubMedGoogle Scholar
  25. 25.
    Yang MH, Wu MZ, Chiou SH, Chen PM, Chang SY, Liu CJ, Teng SC, Wu KJ (2008) Direct regulation of TWIST by HIF-1alpha promotes metastasis. Nat Cell Biol 10(3):295–305.  https://doi.org/10.1038/ncb1691CrossRefPubMedGoogle Scholar
  26. 26.
    Krishnamachary B, Berg-Dixon S, Kelly B, Agani F, Feldser D, Ferreira G, Iyer N, LaRusch J, Pak B, Taghavi P, Semenza GL (2003) Regulation of colon carcinoma cell invasion by hypoxia-inducible factor 1. Cancer Res 63(5):1138–1143PubMedGoogle Scholar
  27. 27.
    Gilkes DM, Xiang L, Lee SJ, Chaturvedi P, Hubbi ME, Wirtz D, Semenza GL (2014) Hypoxia-inducible factors mediate coordinated RhoA-ROCK1 expression and signaling in breast cancer cells. Proc Natl Acad Sci U S A 111(3):E384–E393.  https://doi.org/10.1073/pnas.1321510111CrossRefPubMedGoogle Scholar
  28. 28.
    Erler JT, Bennewith KL, Nicolau M, Dornhofer N, Kong C, Le QT, Chi JT, Jeffrey SS, Giaccia AJ (2006) Lysyl oxidase is essential for hypoxia-induced metastasis. Nature 440(7088):1222–1226.  https://doi.org/10.1038/nature04695CrossRefPubMedGoogle Scholar
  29. 29.
    Gilkes DM, Bajpai S, Wong CC, Chaturvedi P, Hubbi ME, Wirtz D, Semenza GL (2013) Procollagen lysyl hydroxylase 2 is essential for hypoxia-induced breast cancer metastasis. Mol Cancer Res 11(5):456–466.  https://doi.org/10.1158/1541-7786.MCR-12-0629CrossRefPubMedPubMedCentralGoogle Scholar
  30. 30.
    Gilkes DM, Chaturvedi P, Bajpai S, Wong CC, Wei H, Pitcairn S, Hubbi ME, Wirtz D, Semenza GL (2013) Collagen prolyl hydroxylases are essential for breast cancer metastasis. Cancer Res 73(11):3285–3296.  https://doi.org/10.1158/0008-5472.CAN-12-3963CrossRefPubMedPubMedCentralGoogle Scholar
  31. 31.
    Wong CC, Tse AP, Huang YP, Zhu YT, Chiu DK, Lai RK, Au SL, Kai AK, Lee JM, Wei LL, Tsang FH, Lo RC, Shi J, Zheng YP, Wong CM, Ng IO (2014) Lysyl oxidase-like 2 is critical to tumor microenvironment and metastatic niche formation in hepatocellular carcinoma. Hepatology 60(5):1645–1658.  https://doi.org/10.1002/hep.27320CrossRefPubMedGoogle Scholar
  32. 32.
    Zhang H, Wong CC, Wei H, Gilkes DM, Korangath P, Chaturvedi P, Schito L, Chen J, Krishnamachary B, Winnard PT Jr, Raman V, Zhen L, Mitzner WA, Sukumar S, Semenza GL (2012) HIF-1-dependent expression of angiopoietin-like 4 and L1CAM mediates vascular metastasis of hypoxic breast cancer cells to the lungs. Oncogene 31(14):1757–1770.  https://doi.org/10.1038/onc.2011.365CrossRefPubMedGoogle Scholar
  33. 33.
    Erler JT, Bennewith KL, Cox TR, Lang G, Bird D, Koong A, Le QT, Giaccia AJ (2009) Hypoxia-induced lysyl oxidase is a critical mediator of bone marrow cell recruitment to form the premetastatic niche. Cancer Cell 15(1):35–44.  https://doi.org/10.1016/j.ccr.2008.11.012CrossRefPubMedPubMedCentralGoogle Scholar
  34. 34.
    Wong CC, Gilkes DM, Zhang H, Chen J, Wei H, Chaturvedi P, Fraley SI, Wong CM, Khoo US, Ng IO, Wirtz D, Semenza GL (2011) Hypoxia-inducible factor 1 is a master regulator of breast cancer metastatic niche formation. Proc Natl Acad Sci U S A 108(39):16369–16374.  https://doi.org/10.1073/pnas.1113483108CrossRefPubMedPubMedCentralGoogle Scholar
  35. 35.
    Bonnet D, Dick JE (1997) Human acute myeloid leukemia is organized as a hierarchy that originates from a primitive hematopoietic cell. Nat Med 3(7):730–737CrossRefGoogle Scholar
  36. 36.
    Bar EE, Lin A, Mahairaki V, Matsui W, Eberhart CG (2010) Hypoxia increases the expression of stem-cell markers and promotes clonogenicity in glioblastoma neurospheres. Am J Pathol 177(3):1491–1502.  https://doi.org/10.2353/ajpath.2010.091021CrossRefPubMedPubMedCentralGoogle Scholar
  37. 37.
    Ohnishi S, Maehara O, Nakagawa K, Kameya A, Otaki K, Fujita H, Higashi R, Takagi K, Asaka M, Sakamoto N, Kobayashi M, Takeda H (2013) hypoxia-inducible factors activate CD133 promoter through ETS family transcription factors. PLoS One 8(6):e66255.  https://doi.org/10.1371/journal.pone.0066255CrossRefPubMedPubMedCentralGoogle Scholar
  38. 38.
    Mathieu J, Zhang Z, Zhou W, Wang AJ, Heddleston JM, Pinna CM, Hubaud A, Stadler B, Choi M, Bar M, Tewari M, Liu A, Vessella R, Rostomily R, Born D, Horwitz M, Ware C, Blau CA, Cleary MA, Rich JN, Ruohola-Baker H (2011) HIF induces human embryonic stem cell markers in cancer cells. Cancer Res 71(13):4640–4652.  https://doi.org/10.1158/0008-5472.CAN-10-3320CrossRefPubMedPubMedCentralGoogle Scholar
  39. 39.
    Ma B, Chen Y, Chen L, Cheng H, Mu C, Li J, Gao R, Zhou C, Cao L, Liu J, Zhu Y, Chen Q, Wu S (2015) Hypoxia regulates Hippo signalling through the SIAH2 ubiquitin E3 ligase. Nat Cell Biol 17(1):95–103.  https://doi.org/10.1038/ncb3073CrossRefPubMedGoogle Scholar
  40. 40.
    Xiang L, Gilkes DM, Hu H, Takano N, Luo W, Lu H, Bullen JW, Samanta D, Liang H, Semenza GL (2014) Hypoxia-inducible factor 1 mediates TAZ expression and nuclear localization to induce the breast cancer stem cell phenotype. Oncotarget 5(24):12509–12527.  https://doi.org/10.18632/oncotarget.2997CrossRefPubMedPubMedCentralGoogle Scholar
  41. 41.
    Wang Y, Liu Y, Malek SN, Zheng P, Liu Y (2011) Targeting HIF1alpha eliminates cancer stem cells in hematological malignancies. Cell Stem Cell 8(4):399–411.  https://doi.org/10.1016/j.stem.2011.02.006CrossRefPubMedPubMedCentralGoogle Scholar
  42. 42.
    Comerford KM, Wallace TJ, Karhausen J, Louis NA, Montalto MC, Colgan SP (2002) Hypoxia-inducible factor-1-dependent regulation of the multidrug resistance (MDR1) gene. Cancer Res 62(12):3387–3394PubMedGoogle Scholar
  43. 43.
    Gottesman MM, Fojo T, Bates SE (2002) Multidrug resistance in cancer: role of ATP-dependent transporters. Nat Rev Cancer 2(1):48–58.  https://doi.org/10.1038/nrc706CrossRefPubMedGoogle Scholar
  44. 44.
    Rohwer N, Cramer T (2011) Hypoxia-mediated drug resistance: novel insights on the functional interaction of HIFs and cell death pathways. Drug Resist Updat 14(3):191–201.  https://doi.org/10.1016/j.drup.2011.03.001CrossRefPubMedGoogle Scholar
  45. 45.
    Lu H, Samanta D, Xiang L, Zhang H, Hu H, Chen I, Bullen JW, Semenza GL (2015) Chemotherapy triggers HIF-1-dependent glutathione synthesis and copper chelation that induces the breast cancer stem cell phenotype. Proc Natl Acad Sci U S A 112(33):E4600–E4609.  https://doi.org/10.1073/pnas.1513433112CrossRefPubMedPubMedCentralGoogle Scholar
  46. 46.
    Casazza A, Laoui D, Wenes M, Rizzolio S, Bassani N, Mambretti M, Deschoemaeker S, Van Ginderachter JA, Tamagnone L, Mazzone M (2013) Impeding macrophage entry into hypoxic tumor areas by Sema3A/Nrp1 signaling blockade inhibits angiogenesis and restores antitumor immunity. Cancer Cell 24(6):695–709.  https://doi.org/10.1016/j.ccr.2013.11.007CrossRefPubMedGoogle Scholar
  47. 47.
    Chiu DK, Xu IM, Lai RK, Tse AP, Wei LL, Koh HY, Li LL, Lee D, Lo RC, Wong CM, Ng IO, Wong CC (2016) Hypoxia induces myeloid-derived suppressor cell recruitment to hepatocellular carcinoma through chemokine (C-C motif) ligand 26. Hepatology 64(3):797–813.  https://doi.org/10.1002/hep.28655CrossRefPubMedGoogle Scholar
  48. 48.
    Du R, Lu KV, Petritsch C, Liu P, Ganss R, Passegue E, Song H, Vandenberg S, Johnson RS, Werb Z, Bergers G (2008) HIF1alpha induces the recruitment of bone marrow-derived vascular modulatory cells to regulate tumor angiogenesis and invasion. Cancer Cell 13(3):206–220.  https://doi.org/10.1016/j.ccr.2008.01.034CrossRefPubMedPubMedCentralGoogle Scholar
  49. 49.
    Grimshaw MJ, Wilson JL, Balkwill FR (2002) Endothelin-2 is a macrophage chemoattractant: implications for macrophage distribution in tumors. Eur J Immunol 32(9):2393–2400.  https://doi.org/10.1002/1521-4141(200209)32:9<2393::AID-IMMU2393>3.0.CO;2-4CrossRefPubMedGoogle Scholar
  50. 50.
    Leek RD, Hunt NC, Landers RJ, Lewis CE, Royds JA, Harris AL (2000) Macrophage infiltration is associated with VEGF and EGFR expression in breast cancer. J Pathol 190(4):430–436.  https://doi.org/10.1002/(SICI)1096-9896(200003)190:4<430::AID-PATH538>3.0.CO;2-6CrossRefPubMedGoogle Scholar
  51. 51.
    Matschurat S, Knies UE, Person V, Fink L, Stoelcker B, Ebenebe C, Behrensdorf HA, Schaper J, Clauss M (2003) Regulation of EMAP II by hypoxia. Am J Pathol 162(1):93–103.  https://doi.org/10.1016/S0002-9440(10)63801-1CrossRefPubMedPubMedCentralGoogle Scholar
  52. 52.
    Murdoch C, Giannoudis A, Lewis CE (2004) Mechanisms regulating the recruitment of macrophages into hypoxic areas of tumors and other ischemic tissues. Blood 104(8):2224–2234.  https://doi.org/10.1182/blood-2004-03-1109CrossRefPubMedGoogle Scholar
  53. 53.
    Tripathi C, Tewari BN, Kanchan RK, Baghel KS, Nautiyal N, Shrivastava R, Kaur H, Bhatt ML, Bhadauria S (2014) Macrophages are recruited to hypoxic tumor areas and acquire a pro-angiogenic M2-polarized phenotype via hypoxic cancer cell derived cytokines Oncostatin M and Eotaxin. Oncotarget 5(14):5350–5368.  https://doi.org/10.18632/oncotarget.2110CrossRefPubMedPubMedCentralGoogle Scholar
  54. 54.
    Zhang X, Mosser DM (2008) Macrophage activation by endogenous danger signals. J Pathol 214(2):161–178.  https://doi.org/10.1002/path.2284CrossRefPubMedPubMedCentralGoogle Scholar
  55. 55.
    Facciabene A, Peng X, Hagemann IS, Balint K, Barchetti A, Wang LP, Gimotty PA, Gilks CB, Lal P, Zhang L, Coukos G (2011) Tumour hypoxia promotes tolerance and angiogenesis via CCL28 and T(reg) cells. Nature 475(7355):226–230.  https://doi.org/10.1038/nature10169CrossRefPubMedGoogle Scholar
  56. 56.
    Bosco MC, Reffo G, Puppo M, Varesio L (2004) Hypoxia inhibits the expression of the CCR5 chemokine receptor in macrophages. Cell Immunol 228(1):1–7.  https://doi.org/10.1016/j.cellimm.2004.03.006CrossRefPubMedGoogle Scholar
  57. 57.
    Sica A, Saccani A, Bottazzi B, Bernasconi S, Allavena P, Gaetano B, Fei F, LaRosa G, Scotton C, Balkwill F, Mantovani A (2000) Defective expression of the monocyte chemotactic protein-1 receptor CCR2 in macrophages associated with human ovarian carcinoma. J Immunol 164(2):733–738CrossRefGoogle Scholar
  58. 58.
    Kuang DM, Zhao Q, Peng C, Xu J, Zhang JP, Wu C, Zheng L (2009) Activated monocytes in peritumoral stroma of hepatocellular carcinoma foster immune privilege and disease progression through PD-L1. J Exp Med 206(6):1327–1337.  https://doi.org/10.1084/jem.20082173CrossRefPubMedPubMedCentralGoogle Scholar
  59. 59.
    Ye LY, Chen W, Bai XL, Xu XY, Zhang Q, Xia XF, Sun X, Li GG, Hu QD, Fu QH, Liang TB (2016) Hypoxia-induced epithelial-to-mesenchymal transition in hepatocellular carcinoma induces an immunosuppressive tumor microenvironment to promote metastasis. Cancer Res 76(4):818–830.  https://doi.org/10.1158/0008-5472.CAN-15-0977CrossRefPubMedGoogle Scholar
  60. 60.
    Chiu DK, Tse AP, Xu IM, Di Cui J, Lai RK, Li LL, Koh HY, Tsang FH, Wei LL, Wong CM, Ng IO, Wong CC (2017) Hypoxia inducible factor HIF-1 promotes myeloid-derived suppressor cells accumulation through ENTPD2/CD39L1 in hepatocellular carcinoma. Nat Commun 8(1):517.  https://doi.org/10.1038/s41467-017-00530-7CrossRefPubMedPubMedCentralGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  • David Kung-Chun Chiu
    • 1
  • Misty Shuo Zhang
    • 1
  • Aki Pui-Wah Tse
    • 1
  • Carmen Chak-Lui Wong
    • 1
    Email author
  1. 1.Department of PathologyQueen Mary Hospital, The University of Hong KongPokfulamHong Kong

Personalised recommendations