Abstract 2397: Cross-talk of mouse lung fibroblasts with human NSCLC cells in vitro and in vivo: Possible implications for xenograft studies
Authors: Schueler Julia B. , Oswald Eva , Rudisch Albin , Loehr Anne , Sommergruber Wolfgang 
Published: August 2015

One major drawback of preclinical xenograft based models is the lack of most parts of the human tumor microenvironment. Human cancer associated fibroblasts are replaced by murine fibroblasts infiltrating the growing tumor. The determination of tumor-stroma crosstalk between human tumor cells and murine fibroblast will help to understand the biology of these models.

Human lung cancer cell lines Calu-1 and NCI-H1437 were cultured in the presence and absence of primary murine lung fibroblast (MLF) for up to 120 hours. 3×104 cells were cultured either in mono- or co-culture (ratio 1:1) in 24well plates with direct cell-cell contact or in transwell plates. Supernatants were harvested after 8h, 24h, 48h, and 120h. ELISA was performed in triplicates on the following cytokines: human and murine mouse variant of GM-CSF, CXCL1, IL-8, IL-6, MIF, CCL-5 and VEGF. In addition, the proliferation rate of fibroblasts and tumor cells in mono-and co-culture was determined. Growth behavior and metastatic pattern of both NSCLC cell lines was determined in vivo in NOG mice.

In general, human cytokine pattern differed not only between mono- and co-culture but also between the two different tumor cell lines. Human CXCL1 was highly expressed by NCI-H1437 in mono-culture and significantly down regulated by co-cultivation with MLF. In contrast to Calu-1, human IL-6 was significantly up-regulated in a co-culture of NCI-H1437 and MLF. NCI-H1437 cells secreted high amounts of IL-8 and MIF in mono- as well as co-cultures. Again, Calu-1 secreted 10-fold less IL-8 and MIF. Human VEGF secretion was up-regulated in Calu-1 in the presence of MLF. Interestingly, NCI-H1437 secreted high amounts of VEGF regardless of the absence or presence of MLF. Mouse VEGF secretion was up-regulated in co-culture with NCI-H1437 and Calu-1 compared to mono-culture of MLF alone. NCI-H1437 proliferated faster when co-cultured with MLF compared to mono-culture. Calu-1 showed similar proliferation pattern in mono-or co-culture. MLF proliferation was enhanced in co-culture with both human NSCLC lines. Implanted into the lung of NOG mice, both cell lines exhibited similar growth behavior and metastasis rates regardless of the tumor cell´s invasiveness (NCI-H1437 is a grade I, e.g. less invasive adenocarcinoma, whereas Calu-1 is a generally more aggressive grade III epidermoid carcinoma).

Cytokines reported to play an important role in tumor biology were significantly influenced by the presence of MLF. Depending on the investigated cytokine and tumor cell line the presence of MLF induced different cytokine release patterns. NSCLC cell lines enhanced the proliferation rate of MLF indicating an inter-species cross-talk. A deeper understanding of the tumor-stroma crosstalk across species barriers will allow to critically evaluate the predictivity of xenograft models as a drug discovery platform and as a consequence help to improve them.

Citation Format: Julia B. Schueler, Eva Oswald, Albin Rudisch, Anne Loehr, Wolfgang Sommergruber. Cross-talk of mouse lung fibroblasts with human NSCLC cells in vitro and in vivo: Possible implications for xenograft studies. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2397. doi:10.1158/1538-7445.AM2015-2397