ASF-4-1 fibroblast-rich culture increases chemoresistance and mTOR expression of pancreatic cancer BxPC-3 cells at the invasive front in vitro, and promotes tumor growth and invasion in vivo

Pancreatic cancer develops dense stromal tissue through the desmoplastic reaction. The aim of the present study was to assess the effects of a fibroblast-rich environment on the malignant potential of pancreatic cancer. Cells from the human pancreatic cancer cell line BxPC-3 were mixed at a ratio of 1:3 (fibroblast-rich) or 1:1 (fibroblast-poor) with cells from the human skin fibroblast line ASF-4-1. In the fibroblast-rich co-culture, tumor budding was observed and BxPC-3 cells were found to be more resistant to gemcitabine than those in the fibroblast-poor co-culture. Immunohistochemistry revealed that the expression of mammalian target of rapamycin was increased at the invasive front of fibroblast-rich co-cultures. In addition, in mouse xenografts of fibroblast-rich co-cultures, tumors were larger and had a higher Ki-67 index compared with that of the fibroblast-poor co-culture xenografts. These results indicate that fibroblast-rich co-cultures may promote the malignant potential of the pancreatic cancer cell line BxPC-3, both in vitro and in vivo.