Prostate cancer development and progression is associated with the stromal microenvironment which is comprised of various cell populations such as cancer-associated fibroblasts (CAFs) and immune cells with the latter including mast cells. Mast cells play a key role in the inflammatory process. When activated, a mast cell rapidly releases its various chemical mediators into the interstitium. However, little is known about their role in cancer tissue. The aim of this study is to clarify the multiple cellular interactions between human tumour stromal fibroblasts and mast cells on epithelial cell morphology and motility.
The multi-cellular interaction in the prostate microenvironment was examined using a novel 3D cellularised matrix co-culture model. Patient-matched CAFs and non-malignant prostatic fibroblasts (NPFs) isolated and validated from prostatectomy specimens were seeded and stimulated for extracellular matrix deposition, before labelled benign epithelia (BPH-1) was added and co-cultured further. Human mast cells (HMC-1) were co-cultured with CAFs or NPFs and benign epithelia to determine their specific impact on epithelial transformation. Motility (migration speed and displacement) was determined using time-lapse videomicroscopy. Following culture, cells were fixed, stained, and quantitative cell morphometric analyses of epithelial cell shape factor, spread area and orientation was determined using Metamorph software.
After 2 days of co-culture, CAFs, but not NPFs, altered BPH-1 epithelial morphology in a novel in vitro co-culture model. When BPH-1 cell morphology on NPFs or CAFs co-cultured with HMC-1 mast cells and supernatant of HMC-1 cell were compared, mast cells potentiated CAF effects on the epithelium, (shape factor, spread area, migration speed and displacement).
In summary, using a novel quantitative co-culture method in vitro, this study demonstrates mast cell-fibroblast interactions in prostate cancer microenvironment, with mast cell’s potentiating CAF effects on the epithelium.