Poster Presentation Advances in Neuroblastoma Research Congress 2016

TLR3-Mediated innate immune response in the treatment of neuroblastoma (#216)

Li-Ling Lin 1 , Wen-Ming Hsu 2 , Chao-Cheng Huang 3 , Hsinyu Lee 4 , Pei-Yi Wu 4 , Min-Tsui Wu 5 , Hui-Ching Chuang 6 , Chia-Ling Wu 5 , Jiin-Haur Chuang 5
  1. Department of Pediatric Surgery, Department of Medical Research, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
  2. Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan
  3. Biobank and Tissue Bank and Department of Pathology, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, and Chang Gung University College of Medicine, Tao-Yuan, Kaohsiung, Taiwan
  4. Department of Life Science and Institute of Zoology, National Taiwan University, Taipei, Taiwan
  5. Department of Pediatric Surgery, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
  6. Department of Otolaryngology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung , Taiwan

Purpose

Toll-like receptor 3 (TLR3), an initiator of the innate immune response to pathogens, predicts a favorable prognosis when highly expressed in neuroblastoma (NB). In vitro, TLR3 showed a high expression in MYC-nonamplified NB cells. Since the expression of c-MYC/MYCN proteins is high in aggressive NB, it is uncertain to what degree that TLR3 agonists may exert their effects on NB cell death.

Materials and Methods

92 NB patients, 47 nonobese/severe combined immunodeficiency mice, six human NB cell lines were involved in this study. Treatment with TLR3 agonist-polyinosinic-polycytidylic acid [poly(I:C)] was used to examine cell viability, apoptosis and tumor growth in NB. TLR3- induced signaling patterns in NB cell lines were detected by Western blot and in human or mice NB tissue samples were evaluated by immunohistochemistry or quantitative RT-PCR.

Results

Poly(I:C) significantly suppressed the tumor growth of SK-N-AS mice, but not of SK-N-DZ mice. Significant downregulation of c-MYC and upregulation of p-IRF3, active NF-kB, MnSOD, 8-OHdG, activate caspase-3 and cleaved poly (ADP-ribose) polymerase were induced by poly(I:C) in SK-N-AS mice. Knockdown of TLR3 attenuated the inhibition of c-MYC protein expression regulated by poly(I:C) in SK-N-AS cells. In children with NB, positive melanoma differentiation-associated gene 5 (MDA5) staining strongly correlated with MYCN non-amplified NB tissues. In AS cells, simultaneously targeting MDA5 and TLR3 showed the best effect to rescue poly(I:C) induced up-regulation of mitochondrial antiviral signaling protein, caspase-9, active caspase-3, and apoptosis. Patients with double positive staining of MDA5 and TLR3 had the most favorable clinical outcome.  

Conclusion

c-MYC overexpression may increase sensitivity to poly(I:C) treatment in NB, and be suppressed by TLR3 to induce ROS-mediated apoptosis. Activation of MDA5 may serve as a complementary role in the TLR3 activated suppression of NB. The role of TLR3, c-MYC and MDA5 expression in NB may not only shed light on the pathogenesis of NB but also point out a potential therapy of NB by targeting innate immune system.