Published online Sep 7, 2018. doi: 10.3748/wjg.v24.i33.3749
Peer-review started: March 1, 2018
First decision: April 18, 2018
Revised: June 14, 2018
Accepted: June 16, 2018
Article in press: June 16, 2018
Published online: September 7, 2018
Only a few gastrointestinal neuroendocrine tumor lines have been published in the last decades. A major problem is the very heterogeneous pathological terminology when trying to classify these cell lines according to the lately revised WHO classification with regard to their original tumors. Particularly, reports of poorly differentiated neuroendocrine carcinoma (NEC) are very scarce mainly due to their low incidence.
Gaining insights in the biology of large cell NEC is essential for the identification of potentially therapeutic molecular targets of this highly malignant neoplasia. Individual tumor models deliver exceptional tools for further research of these objectives. However, well characterized and low passage NEC models are still rare.
Main objective of the study was the establishing and profound characterization of an patient derived ultra-low passage NEC cell line and corresponding patient-derived xenograft (PDX) model that allows drug response testing and prediction.
Cell line establishment could be realized from direct in vitro culturing of colonic NEC tissue. In addition, a PDX model could be established from frozen tumor samples. Profound analysis of morphological features, invasive and migratory behavior as well as expression of neuroendocrine markers was done. Detailed phenotypic analysis was performed by microscopy and multicolor flow cytometry. Chromosomal aberrations were mapped by array comparative genomic hybridization and DNA profiling was analyzed by DNA fingerprinting. At last drug responsiveness was evaluated and the sensitivity against chemotherapeutic agents assessed.
The cell line displayed characteristic morphological and molecular features of large cell NEC with KI-67 > 50%. In vitro and in vivo experiments demonstrated that the cell line retained their malignant properties. Molecular-pathological analysis revealed a CpG island promoter methylation positive cell line with microsatellite instability being absent. The KRAS gene was not mutated whereas a BRAF V600E mutation was detected. A high sensitivity to such drugs as etoposide, cisplatin and 5-FU could be observed with a more resistant phenotype to rapamycin.
Taken together, this study describes the development and basic characterization of powerful matched in vitro and in vivo patient-derived models not only to perform basic research to better understand the biology of NECs, but also to establish novel therapeutic options.
This descriptive study exemplifies the methodology and characterization of a large cell NEC cell line directly from original patients’ tumor material. This will help to improve the ability for personalizing tumor therapy in the near future.