Establishment, functional and genetic characterization of three novel patient-derived rectal cancer cell lines

ARTICLE HIGHLIGHTS

Research background

It is well known that ultra-low passage and in-depth characterized patient-derived tumor models are highly desirable for basic research and for predicting individual responses to current or novel therapy regimens.

Research motivation

To establish individual tumor models of rectal cancer from patient-derived tumor samples to gain further insights into the biological behavior of rectal cancer.

Research objectives

Main objective of the study was the establishing and profound characterization of new patient-derived rectal cancer cell lines with corresponding patient-derived xenograft models that allow testing of drug response, translational and basic research.

Research methods

Establishment of cell lines could be achieved by direct in vitro culturing and in vivo xenografting with following in vitro culturing. Profound analysis of morphological features, invasive and migratory behavior, phenotype, molecular profile including mutational analysis, and protein expression was done. Responsiveness to current chemotherapeutic drugs was evaluated and sensitivity to radiation and combined radio-chemotherapy was examined. At last the positron emission tomography (PET) tracers ¹⁸F-fluorodeoxyglucose (FDG) and ¹⁸F-fluorothymidine were used to assess glucose metabolism and proliferation activity respectively.

Research results

Three individual ultra-low passage rectal cancer cell lines could be established. In vitro and in vivo experiments demonstrated that all cell lines retained their malignant properties. Molecular analysis classified all three cell lines as sporadic type (CIMP-0/non-MSI-H). Mutational analysis revealed an individual mutational profile of each cell line (HROC126: APC^wt, TP53^wt, KRAS^wt, BRAF^wt, PTEN^wt; HROC239 T0 M1: APC^mut, P53^wt, KRAS^mut, BRAF^wt, PTEN^mut and HROC284Met: APC^wt, P53^mut, KRAS^mut, BRAF^wt, PTEN^mut). The cell lines demonstrated a heterogeneous response to chemotherapy, radiation and combined radio-chemotherapy. Interestingly, analysis of glucose metabolism showed a markedly reduced uptake of the PET tracer ¹⁸F-FDG after combined radio-chemotherapy of all three cell lines.

Research conclusions

Taken together, this study describes the development and in-depth characterization of three patient-derived rectal cancer cell lines that could be established from fresh patients´ tumor samples for the first time. These powerful matched in vitro and in vivo models provide useful tools not only to perform basic research to better understand the biology of rectal cancer, but also to test and establish novel therapy regimens.

Research perspectives

This descriptive study exemplifies the methodology and characterization of rectal cancer cell lines obtained directly from patients´ tumor material. This is an important step to extend the abilities of personalized tumor therapy in the near future.