KRAS mutations in the parental tumour accelerate in vitro growth of tumoroids established from colorectal adenocarcinoma

Abstract

The aim of the present study was to characterize a patient-derived in vitro 3D model (ie tumoroid) established from colorectal adenocarcinoma. This study investigated the growth rate of tumoroids and whether the Kirsten rat sarcoma (KRAS) mutations in the parental tumour accelerate this rate. The tumoroids were established from surgical resections of primary and metastatic colorectal adenocarcinoma from 26 patients. The in vitro growth rate of these tumoroids was monitored by automated imaging and recorded as relative growth rate. The KRAS hotspot mutations were investigated on the parental tumours by Ion Torrent^™ next-generation sequencing. The KRAS mutations were detected in 58% of the parental tumours, and a significantly higher growth rate was observed for tumoroids established from the KRAS-mutated tumours compared to wild-type tumours (P < 0.0001). The average relative growth rate (log10) on day 10 was 0.360 ± 0.180 (mean ± SD) for the KRAS-mutated group and 0.098 ± 0.135 (mean ± SD) for the KRAS wild-type group. These results showed that the presence of KRAS mutations in parental tumours is associated with an acceleration of the growth rate of tumoroids. The future perspective for such a model could be the implementation of chemoassays for personalized medicine.

Keywords: 3D in vitro culture; Kirsten rat sarcoma mutation; colorectal cancer; gastrointestinal pathology; tumoroids.

Figure 1

Tumoroids stained with haematoxylin and eosin. Tumoroids recapitulate the glandular structure of the colorectal epithelium. The cells in the tumoroids show a high nuclear‐cytoplasmic ratio, which indicates the hyperproliferative potential of these cells (a: patient no. 8; b: patient no. 10; c: patient no. 14). (bar = 50 μm) [Colour figure can be viewed at wileyonlinelibrary.com]

Figure 2

Scatter plot with fitted regression line showing log10 values of different relative rate of growth area for tumoroids. Each dot represents the relative rate of growth area in a specific culture‐well for a specific patient. The growth rate of tumoroids established from the parental tumours with mutated KRAS was higher that the growth rate for tumoroids established from the tumours with wild‐type (wt) KRAS ( P < 0.0001) [Colour figure can be viewed at wileyonlinelibrary.com]