Development and Radiation Response Assessment in A Novel Syngeneic Mouse Model of Tongue Cancer: 2D Culture, 3D Organoids and Orthotopic Allografts

Abstract

Oral squamous cell carcinoma (OSCC) are aggressive cancers that contribute to significant morbidity and mortality in humans. Although numerous human xenograft models of OSCC have been developed, only a few syngeneic models of OSCC exist. Here, we report on a novel murine model of OSCC, RP-MOC1, derived from a tongue tumor in a C57Bl/6 mouse exposed to the carcinogen 4-nitroquinoline-1-oxide. Phenotypic characterization and credentialing (STR profiling, exome sequencing) of RP-MOC1 cells was performed in vitro. Radiosensitivity was evaluated in 2D culture, 3D organoids, and in vivo using orthotopic allografts. RP-MOC1 cells exhibited a stable epithelial phenotype with proliferative, migratory and invasive properties. Exome sequencing identified several mutations commonly found in OSCC patients. The LD50 for RP-MOC1 cells in 2D culture and 3D organoids was found to be 2.4 Gy and 12.6 Gy, respectively. Orthotopic RP-MOC1 tumors were pan-cytokeratin+ and Ki-67+. Magnetic resonance imaging of orthotopic RP-MOC1 tumors established in immunocompetent mice revealed marked growth inhibition following 10 Gy and 15 Gy fractionated radiation regimens. This radiation response was completely abolished in tumors established in immunodeficient mice. This novel syngeneic model of OSCC can serve as a valuable platform for the evaluation of combination strategies to enhance radiation response against this deadly disease.

Use of 3D Spheroid Models for the Assessment of RT Response in Head and Neck Cancer

“…In HNC especially, preclinical studies show higher radiosensitivity for HPV-positive HNC when compared to HPV-negative HNC [ 3 , 17 ]. However, data comparing the RT response of HPV-positive versus HPV-negative HNC in 3D spheroids to the existing gold-standard 2D and in vivo models are missing [ 15 , 18 , 19 ]. In this study, we validated the use of 3D spheroids in the RT response to HNC by comparing the RT responses of HPV-positive and HPV-negative 3D spheroids to those of 2D and in vivo models.…”

Animal Models for Radiotherapy Research: All (Animal) Models Are Wrong but Some Are Useful

“…For example, Cosper et al [ 15 ] review the approaches, biological advantages and potential pitfalls of patient-derived models in head and neck cancer. In a corollary article, Vincent-Chong and Seshadri [ 16 ] present a novel syngeneic mouse model of oral squamous cell carcinoma derived from a chemically-induced tongue tumour in a C57BL/6 mouse. The RP-MOOC1 model has mutational and histological similarities to human disease and may prove to be a valuable platform for the evaluation of novel drug-radiotherapy combination strategies, including the use of immune-checkpoint inhibitors (ICIs).…”

Breakdown of Symbiosis in Radiation-Induced Oral Mucositis

“…Furthermore, researchers have developed human mini-3D oral organoids and already exposed them to RT to examine its multiple side effects on the mucosa [ 88 ]. Therefore, exposing oral organoids to oral microbes could provide a novel way to identify mechanisms of host–commensal interactions and eventually to discover novel microbiome-based therapy aimed at solving the fastidious host-microbiome breakdown of symbiosis in RT induced OM.…”

“…Studies in which tongue-derived adult stem cells have been used for tongue organoid cultures have led researchers to rethink the OM models [ 87 ]. A shift towards the use of 3D human organoids is already evident in investigations of mucositis in the gut, as has been seen with the exploitation of “tumoroids” in the study of tumors [ 88 ]. A substantial limitation of these models is the absence of human immune cells and vasculature, but the cocultivation of heterogenous organoids to better study system complexities is already under development.…”