Establishment of an organoid model of nasopharyngeal carcinoma and its in vitro chemosensitivity profile

Abstract

Objective To explore the method for in vitro culture of an organoid model of nasopharyngeal carcinoma (NPC) and examine its in vitro chemosensitivity profile. Methods Fresh specimens of NPC tissues were obtained from clinical patients during nasopharyngoscopic biopsy or nasal endoscopic surgeries. The tumor tissues were cut into pieces, digested with mixed digestive juice and filtered. The NPC cells were isolated by centrifugation, resuspended with Matrix gel and AMDM/F12, and inoculated in a Petri dish for three-dimensional culture of the organoids. Paraffin sections of the NPC organoids cultured for 5 to 7 d were prepared for morphological examination and immunohistochemistry for Ki67 and CD133, CD44 immunofluorescence assay, and EBER in situ hybridization. The NPC organoids cultured for 5 d were tested for chemosensitivity to paclitaxel, cisplatin, carboplatin, gemcitabine and vinorelbine by assessing the cell viability with neutral red staining following treatments with the drugs. Results The cultured NPC organoids showed obvious nuclear atypia, which was consistent with that of the source NPC tissues. The NPC organoids were strongly positive for CD133 and CD44, suggesting the enrichment of tumor stem cells in the organoids. Nearly 30% of the cells in the organoids were positive for Ki67, indicating the proliferative capacity of the organoids. Chemosensitivity tests showed that the NPC organoids were highly sensitive to carboplatin, cisplatin and vinorelbine, and moderately sensitive to gemcitabine, but with a low sensitivity to tigio. Conclusion We successfully established an in vitro culture system of NPC organoids, which can serve as a new NPC model for testing drug sensitivities.

Keywords

• nasopharyngeal carcinoma
• three-dimensional culture
• organoids
• tumor stem cells
• drug sensitivity test