Pancreatic cancer tumorspheres are cancer stem-like cells with increased chemoresistance and reduced metabolic potential

Abstract

Cancer stem cells are a population of slow-cycling cells within the tumour bulk, with self-renewal capacity that attracts interest as a therapeutic target. In highly heterogeneous tumours, like pancreatic ductal adenocarcinoma (PDAC) however, the characterisation of cancer stem cells has led to controversial results due to the lack of consensus on specific markers. Here we investigated the characteristics of a population of pancreatic cancer tumorspheres derived from different human pancreatic cancer cell lines and a primary line from a genetically engineered KPC mouse model, using flow cytometry and western blotting to analyse surface and stemness markers. We analysed tumorspheres tumorigenic potential using anchorage-independent soft agar assay as well as their metabolic plasticity and chemoresistance. Pancreatic cancer tumorspheres display a heterogeneous pattern of surface and stemness markers, nevertheless they are characterised by an increased tumorigenic potential and higher chemoresistance. In addition, we have shown that pancreatic cancer tumorspheres have a unique metabolic profile with reduced metabolic potential. Together our results indicate that, despite the heterogeneity characterising pancreatic cancer tumorspheres, we can identify a functional vulnerability that represents a window for pharmacological intervention and development of novel therapeutic strategies.

Keywords: Cancer spheroids; Tumorigenic potential; Tumour initiating cells.