GM-1111 reduces radiation-induced oral mucositis in mice by targeting pattern recognition receptor-mediated inflammatory signaling

PLoS One. 2021 Mar 26;16(3):e0249343. doi: 10.1371/journal.pone.0249343. eCollection 2021.


Purpose: Oral mucositis (OM) is a common, painful side effect of radiation therapy used for the treatment of head and neck cancer (HNC). Activation of the innate immune system upon irradiation has been identified as a key precipitating event of OM. To better understand OM's pathogenesis, we studied pattern recognition receptors (PRRs) and their downstream pro-inflammatory cytokines in a mouse model of radiation-induced OM. We also tested therapeutic efficacy of GM-1111 that targets innate immune system to reduce radiation-induced OM.

Methods and materials: The pathogenesis of OM was studied in a single X-ray induced mouse model. The severity of OM was measured by visual and microscopical examinations. The irradiation-induced changes of PRRs and their downstream effector cytokine gene expression levels were determined. The efficacy of GM-1111 to reduce OM was tested in single and fractionated irradiation mouse models. The impact of the drug on tumor response to radiation therapy was also tested in a mouse model of human HNC.

Results: Radiation-induced tissue ulcerations were radiation-dosage and -time dependent. The lesions showed selective increases in PRR and pro-inflammatory cytokine gene expression levels. Once daily administration of GM-1111 (≥30 mg/kg, s.c.) significantly reduced the severity and the incidence of OM. The drug had little effect on PRRs but significantly inhibited downstream pro-inflammatory cytokine genes. GM-1111 did not interfere radiation therapy to induce HNC SCC-25 tumor regression. Instead, we observed significant drug-induced tumor regression.

Conclusions: Radiation induces tissue damages. The increased expression levels of PRRs and their downstream pro-inflammatory cytokine genes in the damaged tissues suggest their important contribution to the pathogenesis of OM. Drug GM-1111 that targets these innate immune molecules may be a potential drug candidate as an intervention for OM.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Indans / pharmacology*
  • Inflammation / pathology
  • Male
  • Mice
  • Molecular Targeted Therapy
  • Radiation Injuries / drug therapy*
  • Radiation Injuries / pathology*
  • Receptors, Pattern Recognition / metabolism*
  • Signal Transduction / drug effects*
  • Signal Transduction / radiation effects
  • Stomatitis / drug therapy*
  • Stomatitis / pathology*
  • Thiazoles / pharmacology*


  • 6-amino-2-(N, N-di-n-propylamino)thiazolo(4,5-f)indan
  • Indans
  • Receptors, Pattern Recognition
  • Thiazoles