Aim of the study: The aim of this study was to validate a novel 3D spheroid co-culture model of pancreatic ductal adenocarcinoma (PDAC) cells and pancreatic stellate cells (PSCs), and to use said model as to investigate the effects of PDAC cell and PSC cross-talk on cell proliferation, cell death, migration and chemo-resistance.

Methods: An eGFP-positive PSC line and PDAC cell lines were cultured in 3D spheroid mono- and co-cultures. Activation of the PSCs within the co-culture model was investigated by real time PCR for whole spheroids and spheroid populations sorted by fluorescence activated cell sorting (FACS). To investigate cell proliferation the cell numbers within the cultures were followed over time and the proportions of the different cell types within the co-cultures were monitored by FACS.

Results: The mRNA expression of the PSC activation marker ASMA as well as the ECM proteins collagen I, laminin and lumican, the PDGFbeta receptor (PDGFRb) and the transforming growth factor beta1 (TGFb-1) downstream effector connective tissue growth factor (CTGF), were increased in PSCs within co-cultures compared to mono-cultures. PSCs were initially expanding but then diminished within 3D spheroid co-cultures together with two separate PDAC cell lines (Panc-1 and HPAF-II). Panc-1 cell numbers were seemingly unaffected by the presence of PSCs, but with higher proportions of PSCs the Panc1 cell numbers within the co-cultures initially were lagging behind but then caught up to the numbers within the mono-cultures. This growth switch was correlated with the opposite switch seen for the PSCs. The proliferation of HPAF-II cells, was on the other hand induced within the co-cultures compared to mono-cultures.

Conclusions: PSCs are activated within the 3D spheroid co-cultures. Both tumor cell and PSC proliferation is influenced by co-culturing the cells in the 3D spheroid model. Different PDAC cell – PSC combinations are affected differently. We currently are investigating the effects on cell death and apoptosis, migration and chemo-resistance.

Citation Format: Jessica K. Norberg, Salvatore Nania, Rainer L. Heuchel, Matthias J. Löhr. Pancreatic cancer and stroma cell cross-talk affects cell proliferation in a 3D spheroid co-culture model. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr C40.