Background Biliary tract carcinomas (BTCs) are epithelial malignancies arising in the region between the intrahepatic bile ducts and the ampulla of Vater at the distal end of the common bile duct. Although patients with inoperable BTCs generally receive a chemotherapy regimen of gemcitabine and cisplatin, the effect of these drugs is limited and the 5-year survival rates of patients are very low. The newly developed 3D culture system known as “organoid culture” allows long-term expansion of stem cells into budding cyst-like structures (organoids) with properties resembling those of the original tissues. The aim of this study is to establish in vitro preclinical models for patients with BTCs using the organoid culture technology.

Methods We established organoids using cancer tissues obtained from patients with BTCs. Alterations of genome, gene expression profiles including microRNAs and drug sensitivity were analyzed in BTC organoids.

Results We were successful in establishment and long-term in vitro culture of five organoid lines derived from human BTCs including intrahepatic cholangiocarcinoma, gallbladder cancer and neuroendocrine carcinoma of the ampulla of Vater. These BTC organoids can be stably cultured over a year, whereas organoids derived from non-cancer bile duct and gallbladder tissues ceased proliferating after 15 passages or six months. H&E staining and immunohistochemistry of BTC organoids and the primary tissues demonstrated that BTC organoids closely recapitulate the histopathological features of the primary tumors. The tumor suppressor microRNA miR-34a was suppressed in organoids derived from one case of intrahepatic cholangiocarcinoma, and enforced expression of miR-34a markedly suppressed the growth of these organoids with down-regulation of its target oncogenes. We also examined the effect of the DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-Aza-CdR) on BTC organoids. Treatment with 5-Aza-CdR suppressed the proliferation of all BTC organoids by inducing an anti-viral immune response including activation of interferon-responsive genes.

Conclusions Studies using organoids derived from various BTC cases could potentially pave the way for development of precision medicine for patients with BTCs. These preclinical models for refractory cancers may fill the gap between basic cancer research and patients trials and allow personalized cancer therapy.

Citation Format: Yoshimasa Saito, Toshihide Muramatsu, Yuko Sugiyama, Ryoei Uchida, Ryo Furukawa, Nao Yoshikawa, Tomoko Yamaguchi, Yae Kanai, Hidetsugu Saito. Establishment and long-term in vitro culture of organoids derived from human biliary tract carcinomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4089.