Despite considerable progress in understanding the biology and genetics of cancer progression, the development of effective therapies against cancer need physiological and predictive preclinical models. In this context, patient-derived xenograft (PDX) models has become a standard tool as they reproduce accurately the behavior of tumor of origin, in term of histological and molecular phenotype and response to chemotherapy. Although PDXs in vivo models are indispensable for preclinical studies, they suffer from some limitations due to study costs related to tumor maintenance on mice, variable engraftment rate, growth delay and limited throughput for large-scale drug screening. To address this problem and propose a time a cost effective preclinical screening tool, we developed a panel of PDX-derived low-passage 2D cell lines as a convenient in vitro pre-screening platform to profile compound activity. Different PDX models including breast, lung, colon, melanoma, glioblastoma and hepatoblastoma were tested for their capacity to generate cell lines maintaining the characteristics of the parental PDX tumor and usable for in vitro assays. Today, we succeeded with a series of 50 PDX models with 83% success rate. Tumor cells isolated from PDX tumor tissue were cultured under different media and matrix conditions, allowing at least 5 passages in culture. A Short Tandem Repeat (STR) comparison profile was done with the parental PDX before performing a master bank. We performed short term 2D cytotoxicity assays and long term colony assays to compare cell lines in vitro drug sensitivity with their parental PDX in vivo drug response and overall, the results show that this panel reproduced the drug response profile of the original PDXs with chemotherapies, PARP inhibitors, an ADC (T-DM1) and FGFR-targeting therapies. Moreover, cellular models engrafted back onto mice showed in vivo response to chemotherapies similar to that of the parental PDX confirming the identical behavior of cell line/PDX couples. As the use of cellular models is still considered as a standard for early preclinical test to evaluate drug response before moving to in vivo assays, our PDX-derived cell line platform appeared to be a robust and relevant tool. Furthermore, since the main concern when using in vitro models is the representativeness of the results obtained when transposed to in vivo models, the similarities between cell lines and parental PDX should maximize success of further in vivo preclinical drug development.

Citation Format: Olivier Deas, Sophie Banis, Kathleen Flosseau, Lea Sinayen, Enora Le Ven, Jean-Gabriel Judde, Stefano Cairo. A preclinical platform of PDX-derived cell lines as a tool for pharmacological screening and functional studies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3014.