Patient-Derived Nasopharyngeal Cancer Organoids for Disease Modeling and Radiation Dose Optimization

Abstract

Effective radiation treatment (RT) for recurrent nasopharyngeal cancers (NPC), featuring an intrinsic hypoxic sub-volume, remains a clinical challenge. Lack of disease‐specific in-vitro models of NPC, together with difficulties in establishing patient derived xenograft (PDX) models, have further hindered development of personalized therapeutic options. Herein, we established two NPC organoid lines from recurrent NPC PDX models and further characterized and compared these models with original patient tumors using RNA sequencing analysis. Organoids were cultured in hypoxic conditions to examine the effects of hypoxia and radioresistance. These models were then utilized to determine the radiobiological parameters, such as α/β ratio and oxygen enhancement ratio (OER), characteristic to radiosensitive normoxic and radioresistant hypoxic NPC, using simple dose-survival data analytic tools. The results were further validated in-vitro and in-vivo, to determine the optimal boost dose and fractionation regimen required to achieve effective NPC tumor regression. Despite the differences in tumor microenvironment due to the lack of human stroma, RNA sequencing analysis revealed good correlation of NPC PDX and organoid models with patient tumors. Additionally, the established models also mimicked inter-tumoral heterogeneity. Hypoxic NPC organoids were highly radioresistant and had high α/β ratio compared to its normoxic counterparts. In-vitro and in-vivo fractionation studies showed that hypoxic NPC was less sensitive to RT fractionation scheme and required a large bolus dose or 1.4 times of the fractionated dose that was effective against normoxic cells in order to compensate for oxygen deficiency. This study is the first direct experimental evidence to predict optimal RT boost dose required to cause sufficient damage to recurrent hypoxic NPC tumor cells, which can be further used to develop dose-painting algorithms in clinical practice.

The Stromal and Immune Landscape of Nasopharyngeal Carcinoma and Its Implications for Precision Medicine Targeting the Tumor Microenvironment

“…However, functional analysis on NPC greatly suffers from the lack of reliable animal models. It is needed to establish a humanized mouse model with a competent human-originated immune system so that NPCmediated immune regulation can be studied in vivo and predict clinical outcomes in NPC patients (131). Currently, NPC organoid is also underdeveloped in multiple groups around the world which can also serve an important alternative to study the function and interaction in vivo from NPC patient derived tissues, and to study the feasibility and efficacy of proposed therapeutic strategies (132).…”

Establishment of a patient-derived organoid model and living biobank for nasopharyngeal carcinoma

“…In January 2021, Professor Sasidharan Swarnalatha Lucky published an article saying that PDX-derived nasopharyngeal carcinoma organoids were established for the study of nasopharyngeal carcinoma radiotherapy ( 19 ). In June of the same year, Professor Deng publicized the establishment of nasopharyngeal carcinoma organoids for the study of the molecular mechanism of nasopharyngeal carcinoma ( 20 ).…”

Application of immune enhanced organoids in modeling personalized Merkel cell carcinoma research

“…Establishing positive predictive value will be a necessary endpoint in future studies. Finally, although radiation is a potential treatment options for MCC, we did not incorporate this treatment parameter in our study as previously described in other primaries 33 .…”