Article | Published:

CDKN1A regulates Langerhans cell survival and promotes Treg cell generation upon exposure to ionizing irradiation

Nature Immunology volume 16, pages 10601068 (2015) | Download Citation


Treatment with ionizing radiation (IR) can lead to the accumulation of tumor-infiltrating regulatory T cells (Treg cells) and subsequent resistance of tumors to radiotherapy. Here we focused on the contribution of the epidermal mononuclear phagocytes Langerhans cells (LCs) to this phenomenon because of their ability to resist depletion by high-dose IR. We found that LCs resisted apoptosis and rapidly repaired DNA damage after exposure to IR. In particular, we found that the cyclin-dependent kinase inhibitor CDKN1A (p21) was overexpressed in LCs and that Cdkn1a−/− LCs underwent apoptosis and accumulated DNA damage following IR treatment. Wild-type LCs upregulated major histocompatibility complex class II molecules, migrated to the draining lymph nodes and induced an increase in Treg cell numbers upon exposure to IR, but Cdkn1a−/− LCs did not. Our findings suggest a means for manipulating the resistance of LCs to IR to enhance the response of cutaneous tumors to radiotherapy.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


Primary accessions

Gene Expression Omnibus


  1. 1.

    , , & DNA-damage response in tissue-specific and cancer stem cells. Cell Stem Cell 8, 16–29 (2011).

  2. 2.

    , & New paradigms and future challenges in radiation oncology: an update of biological targets and technology. Sci. Transl. Med. 5, 173sr172 (2013).

  3. 3.

    et al. Toll-like receptor 4-dependent contribution of the immune system to anticancer chemotherapy and radiotherapy. Nat. Med. 13, 1050–1059 (2007).

  4. 4.

    et al. Radiation-induced equilibrium is a balance between tumor cell proliferation and T cell-mediated killing. J. Immunol. 190, 5874–5881 (2013).

  5. 5.

    et al. STING-dependent cytosolic DNA sensing promotes radiation-induced type I interferon-dependent antitumor immunity in immunogenic tumors. Immunity 41, 843–852 (2015).

  6. 6.

    et al. Therapeutic effects of ablative radiation on local tumor require CD8+ T cells: changing strategies for cancer treatment. Blood 114, 589–595 (2009).

  7. 7.

    Spinning molecular immunology into successful immunotherapy. Nat. Rev. Immunol. 2, 227–238 (2002).

  8. 8.

    et al. Safety, activity, and immune correlates of anti-PD-1 antibody in cancer. N. Engl. J. Med. 366, 2443–2454 (2012).

  9. 9.

    , , , & Transient regulatory T cell ablation deters oncogene-driven breast cancer and enhances radiotherapy. J. Exp. Med. 210, 2435–2466 (2013).

  10. 10.

    & Oncology meets immunology: the cancer-immunity cycle. Immunity 39, 1–10 (2013).

  11. 11.

    et al. Dendritic cells, monocytes and macrophages: a unified nomenclature based on ontogeny. Nat. Rev. Immunol. 14, 571–578 (2014).

  12. 12.

    , & Origin, homeostasis and function of Langerhans cells and other langerin-expressing dendritic cells. Nat. Rev. Immunol. 8, 935–947 (2008).

  13. 13.

    et al. Langerhans cells renew in the skin throughout life under steady-state conditions. Nat. Immunol. 3, 1135–1141 (2002).

  14. 14.

    & The role of antigen-presenting cells in triggering graft-versus-host disease and graft-versus-leukemia. Blood 110, 9–17 (2007).

  15. 15.

    , & Dendritic cell and macrophage heterogeneity in vivo. Immunity 35, 323–335 (2011).

  16. 16.

    et al. Exposure to Ionizing Radiation Induces the Migration of Cutaneous Dendritic Cells by a CCR7-Dependent Mechanism. J. Immunol. 189, 4247–4257 (2012).

  17. 17.

    , , & Migration of skin dendritic cells in response to ionizing radiation exposure. Radiat. Res. 171, 687–697 (2009).

  18. 18.

    et al. CCR7 governs skin dendritic cell migration under inflammatory and steady-state conditions. Immunity 21, 279–288 (2004).

  19. 19.

    & γ-H2AX - A novel biomarker for DNA double-strand breaks. In Vivo 22, 305–309 (2008).

  20. 20.

    & The comet assay: a method to measure DNA damage in individual cells. Nat. Protoc. 1, 23–29 (2006).

  21. 21.

    , , & An optimized method for measurement of gamma-H2AX in blood mononuclear and cultured cells. Nat. Protoc. 3, 1187–1193 (2008).

  22. 22.

    et al. Prevention of UV radiation-induced immunosuppression by IL-12 is dependent on DNA repair. J. Exp. Med. 201, 173–179 (2005).

  23. 23.

    & p21 in cancer: intricate networks and multiple activities. Nat. Rev. Cancer 9, 400–414 (2009).

  24. 24.

    et al. p21WAF1 expression is associated with improved survival after adjuvant chemoradiation for pancreatic cancer. Surgery 128, 520–530 (2000).

  25. 25.

    et al. The cell cycle inhibitor p21 controls T-cell proliferation and sex-linked lupus development. Nat. Med. 6, 171–176 (2000).

  26. 26.

    et al. Loss of p21 CDKN1A impairs entry to quiescence and activates a DNA damage response in normal fibroblasts induced to quiescence. Cell Cycle 8, 105–114 (2009).

  27. 27.

    et al. Two distinct types of Langerhans cells populate the skin during steady state and inflammation. Immunity 37, 905–916 (2012).

  28. 28.

    & P53 and radiation responses. Oncogene 22, 5774–5783 (2003).

  29. 29.

    et al. Transcription factor Foxo3 controls the magnitude of T cell immune responses by modulating the function of dendritic cells. Nat. Immunol. 10, 504–513 (2009).

  30. 30.

    et al. The ataxia telangiectasia mutated kinase pathway regulates IL-23 expression by human dendritic cells. J. Immunol. 190, 3246–3255 (2013).

  31. 31.

    et al. Specialized role of migratory dendritic cells in peripheral tolerance induction. J. Clin. Invest. 123, 844–854 (2013).

  32. 32.

    p21(WAF1/Cip1): more than a break to the cell cycle? Biochimica Biophysica Acta Rev. Cancer 1471, M43–M56 (2000).

  33. 33.

    & The role of the cyclin-dependent kinase inhibitor p21 in apoptosis. Mol. Cancer Ther. 1, 639–649 (2002).

  34. 34.

    , , & Loss of p21Waf1/Cip1 sensitizes tumors to radiation by an apoptosis-independent mechanism. Cancer Res. 57, 4703–4706 (1997).

  35. 35.

    & p53-dependent apoptosis or growth arrest induced by different forms of radiation in U2OS cells: p21WAF1/CIP1 repression in UV induced apoptosis. Oncogene 18, 5403–5412 (1999).

  36. 36.

    , , & A p53 and apoptotic independent role for p21waf1 in tumour response to radiation therapy. Oncogene 18, 6540–6545 (1999).

  37. 37.

    , , & bcl-xL is critical for dendritic cell survival in vivo. J. Immunol. 173, 4425–4432 (2004).

  38. 38.

    et al. Langerhans cells facilitate epithelial DNA damage and squamous cell carcinoma. Science 335, 104–108 (2012).

  39. 39.

    et al. Langerhans cells are required for UVR-induced immunosuppression. J. Invest. Dermatol. 130, 1419–1427 (2010).

  40. 40.

    , & The mechanism of action of radiosensitization of conventional chemotherapeutic agents. Semin. Radiat. Oncol. 13, 13–21 (2003).

  41. 41.

    et al. Radiation enhances regulatory T cell representation. Int. J. Radiat. Oncol. Biol. Phys. 81, 1128–1135 (2011).

  42. 42.

    & Combining radiotherapy and cancer immunotherapy: a paradigm shift. J. Natl. Cancer Inst. 105, 256–265 (2013).

  43. 43.

    , & Strategies to improve radiotherapy with targeted drugs. Nat. Rev. Cancer 11, 239–253 (2011).

  44. 44.

    Mechanisms of suppression by suppressor T cells. Nat. Immunol. 6, 338–344 (2005).

  45. 45.

    et al. The efficacy of radiotherapy relies upon induction of type i interferon-dependent innate and adaptive immunity. Cancer Res. 71, 2488–2496 (2011).

  46. 46.

    et al. Low-dose irradiation programs macrophage differentiation to an iNOS+/M1 phenotype that orchestrates effective T cell immunotherapy. Cancer Cell 24, 589–602 (2013).

  47. 47.

    et al. The origin and development of nonlymphoid tissue CD103+ DCs. J. Exp. Med. 206, 3115–3130 (2009).

  48. 48.

    B16 as a mouse model for human melanoma. Current Protocols in Immunology 2001 (May, Chapter 20, Unit 20).

  49. 49.

    et al. Deciphering the transcriptional network of the dendritic cell lineage. Nat. Immunol. 13, 888–899 (2012).

  50. 50.

    , , & Statistics of the Comet assay: a key to discriminate between genotoxic effects. Mutagenesis 18, 159–166 (2003).

Download references


We thank J. Manfredi and S. Aronson (Icahn School of Medicine at Mount Sinai) for Trp53−/− mice; P. Heeger (Icahn School of Medicine at Mount Sinai) for FoxP3-DTR mice; M.C. Nussenzweig (The Rockefeller University) for Ly75−/− mice; S. Ghaffari (Icahn School of Medicine at Mount Sinai) for Foxo3−/− mice; C. Rivera for help in maintaining mouse colonies; R. Bagnell (University of North Carolina) for the Image-J CometScore module; A. Nussenzweig for input on the manuscript; the Flow Cytometry, Microscopy, and Irradiator Shared Resource Facilities of the Icahn School of Medicine at Mount Sinai for contributions; and the Immunological Genome Project Consortium for resources. Supported by the US National Institutes of Health (T32 CA078207-14 and T32 GM007280 to J.G.P.), the American Medical Association (J.G.P.), the National Institute of Arthritis, Musculoskeletal and Skin Diseases of the US National Institutes of Health (R00 AR062595 to J.I.) and the National Cancer Institute of the US National Institutes of Health (R01 CA173861 and R01 CA154947 to M.M.).

Author information

Author notes

    • Juliana Idoyaga

    Present address: Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA.

    • Jeremy G Price
    •  & Juliana Idoyaga

    These authors contributed equally to this work.


  1. Department of Oncological Sciences and Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.

    • Jeremy G Price
    • , Juliana Idoyaga
    • , Hélène Salmon
    • , Brandon Hogstad
    • , Saghi Ghaffari
    • , Marylene Leboeuf
    •  & Miriam Merad
  2. Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.

    • Jeremy G Price
    • , Juliana Idoyaga
    • , Hélène Salmon
    • , Brandon Hogstad
    • , Marylene Leboeuf
    •  & Miriam Merad
  3. Laboratory of Cellular Physiology and Immunology and Chris Browne Center for Immunology and Immune Diseases, The Rockefeller University, New York, New York, USA.

    • Juliana Idoyaga
  4. Department of Developmental & Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.

    • Carolina L Bigarella
    •  & Saghi Ghaffari
  5. Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA.

    • Saghi Ghaffari
  6. Department of Medicine, Division of Hematology, Oncology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.

    • Saghi Ghaffari


  1. Search for Jeremy G Price in:

  2. Search for Juliana Idoyaga in:

  3. Search for Hélène Salmon in:

  4. Search for Brandon Hogstad in:

  5. Search for Carolina L Bigarella in:

  6. Search for Saghi Ghaffari in:

  7. Search for Marylene Leboeuf in:

  8. Search for Miriam Merad in:


J.G.P., J.I. and M.M. contributed to the design of and discussions of the work; J.G.P. and J.I. performed experiments, analyzed data and prepared the figures; H.S. contributed to in vivo tumor experiments; B.H. contributed to RT-PCR experiments; C.L.B. and S.G. developed protocols for the comet assay and provided Foxo3−/− mice; M.L. contributed to the maintenance of animal colonies and generation of BM chimeras; J.G.P., J.I. and M.M. wrote the manuscript; and all authors edited the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Miriam Merad.

Integrated supplementary information

Supplementary information

PDF files

  1. 1.

    Supplementary Text and Figures

    Figures 1–6

  2. 2.

    Supplementary Table 1

    List of antibodies for flow cytometry

About this article

Publication history





Further reading