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Preventive and therapeutic effects of Smad7 on radiation-induced oral mucositis

Nature Medicine volume 19, pages 421428 (2013) | Download Citation


We report that K5.Smad7 mice, which express a Smad7 transgene under the control of a keratin 5 promoter, were resistant to radiation-induced oral mucositis, a painful oral ulceration. In addition to nuclear factor κB (NF-κB) activation, which is known to contribute to oral mucositis, we found activated transforming growth factor β (TGF-β) signaling in cells from this condition. Smad7 dampened both pathways to attenuate inflammation, growth inhibition and apoptosis. Additionally, Smad7 promoted oral epithelial migration to close the wound. Further analyses revealed that TGF-β signaling Smads and their co-repressor C-terminal binding protein 1 (CtBP1) transcriptionally repressed Rac1, and that Smad7 abrogated this repression. Knocking down Rac1 expression in mouse keratinocytes abrogated Smad7-induced migration. Topical application of Smad7 protein conjugated with a cell-permeable Tat tag to oral mucosa showed prophylactic and therapeutic effects on radiation-induced oral mucositis in mice. Thus, we have identified new molecular mechanisms involved in oral mucositis pathogenesis, and our data suggest an alternative therapeutic strategy to block multiple pathological processes in this condition.

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This work was supported by NIH grants AR061792 and DE015953 to X.-J.W., R01CA115468 to Q.Z. and R03DA033982 to R.Z. and Q.Z. and the Colorado State/University of Colorado Bioscience Discovery Evaluation grant to X.-J.W., Q.Z. and Y.R. and was partially supported by NIH grant P30CA046934 to the University of Colorado Cancer Center. L.B. was supported by a grant (81060189) from The National Natural Science Foundation of China (NSFC). F.L. was supported by grants from the NSFC (81102596), The Shanghai Rising-Star Program (12QA1403300) and The Innovation Program of Shanghai Municipal Education Commission (12YZ067). The authors thank S. Said, C. Marshall and C. Liu for searching human oral mucositis clinical samples and C.Y. Li and G. Gang for their input on radiotherapy in patients with oral cancer. The authors also thank P. Garl for proofreading the manuscript.

Author information

Author notes

    • Gangwen Han
    • , Li Bian
    •  & Fulun Li

    These authors contributed equally to this work.


  1. Department of Pathology, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado, USA.

    • Gangwen Han
    • , Li Bian
    • , Fulun Li
    • , Donna Wang
    •  & Xiao-Jing Wang
  2. Department of Pathology, The First Affiliated Hospital of Kunming Medical University, Kunming, China.

    • Li Bian
    •  & Jianbo Lu
  3. Department of Dermatology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.

    • Fulun Li
  4. Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health (NIH), Bethesda, Maryland, USA.

    • Ana Cotrim
    •  & J Silvio Gutkind
  5. Department of Dermatology, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado, USA.

    • Yu Deng
    • , Gregory Bird
    • , Yosef Refaeli
    •  & Qinghong Zhang
  6. Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, USA.

    • Anastasia Sowers
    •  & James B Mitchell
  7. Department of Molecular Genetics and Biochemistry, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.

    • Rui Zhao
  8. Department of Radiation Oncology, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado, USA.

    • David Raben
  9. Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands.

    • Peter ten Dijke


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G.H., Q.Z. and X.-J.W. designed experiments and wrote the manuscript. D.R. provided input in radiotherapy dosing and regimens in oral cancer treatment and clinical care of radiation-induced oral mucositis and the MSK921 cell line. G.H., L.B., F.L. and D.W. performed the radiation-induced oral mucositis animal experiments and other histopathological and molecular analyses at the University of Colorado Denver, Anschutz Medical Campus. A.C., A.S. and J.B.M. performed radiation-induced oral mucositis animal experiments at the NIH. Y.D., G.B. and Q.Z. performed protein purification. R.Z., Y.R. and Q.Z. contributed to optimization of Tat-Smad7 protein production. J.S.G. provided NOK-SI cells. P.t.D. provided Smad7-specific antibody. L.B. and J.L. provided human samples and performed immunostaining on those samples. D.R., J.B.M. and J.S.G. provided suggestions for manuscript revisions.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Qinghong Zhang or Xiao-Jing Wang.

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