Combining immunotherapy with high-dose radiation therapy (HDRT) significantly inhibits tumor growth in a syngeneic mouse model of high-risk neuroblastoma

Shuobo Boboila; Shunpei Okochi; Debarshi Banerjee; Sunjay Barton; Cherease Street; Ariela L Zenilman; Qi Wang; Robyn D Gartrell; Yvonne M Saenger; David Welch; Cheng-Chia Wu; Angela Kadenhe-Chiweshe; Darrell J Yamashiro; Eileen P Connolly

doi:10.1016/j.heliyon.2023.e17399

Combining immunotherapy with high-dose radiation therapy (HDRT) significantly inhibits tumor growth in a syngeneic mouse model of high-risk neuroblastoma

Heliyon. 2023 Jun 19;9(6):e17399. doi: 10.1016/j.heliyon.2023.e17399. eCollection 2023 Jun.

Authors

Affiliations

¹ Department of Radiation Oncology, Columbia University Irving Medical Center, New York, NY 10032, USA.
² Department of Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA.
³ Department of Pediatrics, Columbia University Irving Medical Center, New York, NY 10032, USA.
⁴ Department of Medicine, Columbia University Irving Medical Center, New York, NY 10032, USA.
⁵ Department of Pathology, Columbia University Irving Medical Center, New York, NY 10032, USA.

Abstract

Purpose: The mortality in patients with MYCN-amplified high-risk neuroblastoma remains greater than 50% despite advances in multimodal therapy. Novel therapies are urgently needed that requires preclinical evaluation in appropriate mice models. Combinatorial treatment with high-dose radiotherapy (HDRT) and immunotherapy has emerged as an effective treatment option in a variety of cancers. Current models of neuroblastoma do not recapitulate the anatomic and immune environment in which multimodal therapies can be effectively tested, and there is a need for an appropriate syngeneic neuroblastoma mice model to study interaction of immunotherapy with host immune cells. Here, we develop a novel syngeneic mouse model of MYCN-amplified neuroblastoma and report the relevance and opportunities of this model to study radiotherapy and immunotherapy.

Materials and methods: A syngeneic allograft tumor model was developed using the murine neuroblastoma cell line 9464D derived a tumor from TH-MYCN transgenic mouse. Tumors were generated by transplanting 1 mm³ portions of 9464D flank tumors into the left kidney of C57Bl/6 mice. We investigated the effect of combining HDRT with anti-PD1 antibody on tumor growth and tumor microenvironment. HDRT (8 Gy x 3) was delivered by the small animal radiation research platform (SARRP). Tumor growth was monitored by ultrasound. To assess the effect on immune cells tumors sections were co-imuunostained for six biomarkers using the Vectra multispectral imaging platform.

Results: Tumor growth was uniform and confined to the kidney in 100% of transplanted tumors. HDRT was largely restricted to the tumor region with minimal scattered out-of-field dose. Combinatorial treatment with HDRT and PD-1 blockade significantly inhibited tumor growth and prolonged mice survival. We observed augmented T-lymphocyte infiltration, especially CD3⁺CD8⁺ lymphocytes, in tumors of mice which received combination treatment.

Conclusion: We have developed a novel syngeneic mouse model of MYCN amplified high-risk neuroblastoma. We have utilized this model to show that combining immunotherapy with HDRT inhibits tumor growth and prolongs mice survival.

Keywords: Cancer therapeutics; Combination therapy; High dose radiation therapy; Immunotherapy; MYCN-amplified neuroblastoma; Neuroblastoma; Novel syngeneic mouse model.